Viewport Size Code:
Login | Create New Account


About | Classical Genetics | Timelines | What's New | What's Hot

About | Classical Genetics | Timelines | What's New | What's Hot


Bibliography Options Menu

Hide Abstracts   |   Hide Additional Links
Long bibliographies are displayed in blocks of 100 citations at a time. At the end of each block there is an option to load the next block.

Bibliography on: Microbial Ecology

The Electronic Scholarly Publishing Project: Providing world-wide, free access to classic scientific papers and other scholarly materials, since 1993.


ESP: PubMed Auto Bibliography 29 May 2020 at 01:45 Created: 

Microbial Ecology

Wikipedia: Microbial Ecology (or environmental microbiology) is the ecology of microorganisms: their relationship with one another and with their environment. It concerns the three major domains of life — Eukaryota, Archaea, and Bacteria — as well as viruses. Microorganisms, by their omnipresence, impact the entire biosphere. Microbial life plays a primary role in regulating biogeochemical systems in virtually all of our planet's environments, including some of the most extreme, from frozen environments and acidic lakes, to hydrothermal vents at the bottom of deepest oceans, and some of the most familiar, such as the human small intestine. As a consequence of the quantitative magnitude of microbial life (Whitman and coworkers calculated 5.0×1030 cells, eight orders of magnitude greater than the number of stars in the observable universe) microbes, by virtue of their biomass alone, constitute a significant carbon sink. Aside from carbon fixation, microorganisms' key collective metabolic processes (including nitrogen fixation, methane metabolism, and sulfur metabolism) control global biogeochemical cycling. The immensity of microorganisms' production is such that, even in the total absence of eukaryotic life, these processes would likely continue unchanged.

Created with PubMed® Query: "microbial ecology" NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2020-05-28

Möhlmann TWR, Vogels CBF, Göertz GP, et al (2020)

Impact of Gut Bacteria on the Infection and Transmission of Pathogenic Arboviruses by Biting Midges and Mosquitoes.

Microbial ecology pii:10.1007/s00248-020-01517-6 [Epub ahead of print].

Tripartite interactions among insect vectors, midgut bacteria, and viruses may determine the ability of insects to transmit pathogenic arboviruses. Here, we investigated the impact of gut bacteria on the susceptibility of Culicoides nubeculosus and Culicoides sonorensis biting midges for Schmallenberg virus, and of Aedes aegypti mosquitoes for Zika and chikungunya viruses. Gut bacteria were manipulated by treating the adult insects with antibiotics. The gut bacterial communities were investigated using Illumina MiSeq sequencing of 16S rRNA, and susceptibility to arbovirus infection was tested by feeding insects with an infectious blood meal. Antibiotic treatment led to changes in gut bacteria for all insects. Interestingly, the gut bacterial composition of untreated Ae. aegypti and C. nubeculosus showed Asaia as the dominant genus, which was drastically reduced after antibiotic treatment. Furthermore, antibiotic treatment resulted in relatively more Delftia bacteria in both biting midge species, but not in mosquitoes. Antibiotic treatment and subsequent changes in gut bacterial communities were associated with a significant, 1.8-fold increased infection rate of C. nubeculosus with Schmallenberg virus, but not for C. sonorensis. We did not find any changes in infection rates for Ae. aegypti mosquitoes with Zika or chikungunya virus. We conclude that resident gut bacteria may dampen arbovirus transmission in biting midges, but not so in mosquitoes. Use of antimicrobial compounds at livestock farms might therefore have an unexpected contradictory effect on the health of animals, by increasing the transmission of viral pathogens by biting midges.

RevDate: 2020-05-28

Yang M, Shi J, Wang B, et al (2020)

Control of Hydraulic Load on Bacterioplankton Diversity in Cascade Hydropower Reservoirs, Southwest China.

Microbial ecology pii:10.1007/s00248-020-01523-8 [Epub ahead of print].

Hydroelectric reservoirs are highly regulated ecosystems, where the understanding on bacterioplankton has been very limited so far. In view of significant changes in river hydrological conditions by dam construction, hydraulic load (i.e., the ratio of mean water depth to water retention time) was assumed to control bacterioplankton diversity in cascading hydropower reservoirs. To evaluate this hypothesis, we investigated bacterioplankton composition and diversity using high-throughput sequencing and related environmental variables in eleven reservoirs on the Wujiang River, Southwest China. Our results showed a decrease of bacterioplankton diversity index with an increase of reservoir hydraulic load. This is because hydraulic load governs dissolved oxygen variation in the water column, which is a key factor shaping bacterioplankton composition in these hydroelectric reservoirs. In contrast, bacterioplankton abundance was mainly affected by nutrient-related environmental factors. Therefore, from a hydrological perspective, hydraulic load is a decisive factor for the bacterioplankton diversity in the hydroelectric reservoirs. This study can improve the understanding of reservoir bacterial ecology, and the empirical relationship between hydraulic load and bacterioplankton diversity index will help to quantitatively evaluate ecological effects of river damming.

RevDate: 2020-05-28

Flanagan E, Lamport D, Brennan L, et al (2020)

Nutrition and the ageing brain: Moving towards clinical applications.

Ageing research reviews pii:S1568-1637(20)30214-2 [Epub ahead of print].

The global increases in life expectancy and population have resulted in a growing ageing population and with it a growing number of people living with age-related neurodegenerative conditions and dementia, shifting focus towards methods of prevention, with lifestyle approaches such as nutrition representing a promising avenue for further development. This overview summarises the main themes discussed during the 3rd Symposium on "Nutrition for the Ageing Brain: Moving Towards Clinical Applications" held in Madrid in August 2018, enlarged with the current state of knowledge on how nutrition influences healthy ageing and gives recommendations regarding how the critical field of nutrition and neurodegeneration research should move forward into the future. Specific nutrients are discussed as well as the impact of multi-nutrient and whole diet approaches, showing particular promise to combatting the growing burden of age-related cognitive decline. The emergence of new avenues for exploring the role of diet in healthy ageing, such as the impact of the gut microbiome and development of new techniques (imaging measures of brain metabolism, metabolomics, biomarkers) are enabling researchers to approach finding answers to these questions. But the translation of these findings into clinical and public health contexts remains an obstacle due to significant shortcomings in nutrition research or pressure on the scientific community to communicate recommendations to the general public in a convincing and accessible way. Some promising programs exist but further investigation to improve our understanding of the mechanisms by which nutrition can improve brain health across the human lifespan is still required.

RevDate: 2020-05-28

Roelofs D, Zwaenepoel A, Sistermans T, et al (2020)

Multi-faceted analysis provides little evidence for recurrent whole-genome duplications during hexapod evolution.

BMC biology, 18(1):57 pii:10.1186/s12915-020-00789-1.

BACKGROUND: Gene duplication events play an important role in the evolution and adaptation of organisms. Duplicated genes can arise through different mechanisms, including whole-genome duplications (WGDs). Recently, WGD was suggested to be an important driver of evolution, also in hexapod animals.

RESULTS: Here, we analyzed 20 high-quality hexapod genomes using whole-paranome distributions of estimated synonymous distances (KS), patterns of within-genome co-linearity, and phylogenomic gene tree-species tree reconciliation methods. We observe an abundance of gene duplicates in the majority of these hexapod genomes, yet we find little evidence for WGD. The majority of gene duplicates seem to have originated through small-scale gene duplication processes. We did detect segmental duplications in six genomes, but these lacked the within-genome co-linearity signature typically associated with WGD, and the age of these duplications did not coincide with particular peaks in KS distributions. Furthermore, statistical gene tree-species tree reconciliation failed to support all but one of the previously hypothesized WGDs.

CONCLUSIONS: Our analyses therefore provide very limited evidence for WGD having played a significant role in the evolution of hexapods and suggest that alternative mechanisms drive gene duplication events in this group of animals. For instance, we propose that, along with small-scale gene duplication events, episodes of increased transposable element activity could have been an important source for gene duplicates in hexapods.

RevDate: 2020-05-27

De Boeck I, van den Broek MFL, Allonsius CN, et al (2020)

Lactobacilli Have a Niche in the Human Nose.

Cell reports, 31(8):107674.

Although an increasing number of beneficial microbiome members are characterized for the human gut and vagina, beneficial microbes are underexplored for the human upper respiratory tract (URT). In this study, we demonstrate that taxa from the beneficial Lactobacillus genus complex are more prevalent in the healthy URT than in patients with chronic rhinosinusitis (CRS). Several URT-specific isolates are cultured, characterized, and further explored for their genetic and functional properties related to adaptation to the URT. Catalase genes are found in the identified lactobacilli, which is a unique feature within this mostly facultative anaerobic genus. Moreover, one of our isolated strains, Lactobacillus casei AMBR2, contains fimbriae that enable strong adherence to URT epithelium, inhibit the growth and virulence of several URT pathogens, and successfully colonize nasal epithelium of healthy volunteers. This study thus demonstrates that specific lactobacilli are adapted to the URT and could have a beneficial keystone function in this habitat.

RevDate: 2020-05-27

Alderliesten JB, Duxbury SJN, Zwart MP, et al (2020)

Effect of donor-recipient relatedness on the plasmid conjugation frequency: a meta-analysis.

BMC microbiology, 20(1):135 pii:10.1186/s12866-020-01825-4.

BACKGROUND: Conjugation plays a major role in the transmission of plasmids encoding antibiotic resistance genes in both clinical and general settings. The conjugation efficiency is influenced by many biotic and abiotic factors, one of which is the taxonomic relatedness between donor and recipient bacteria. A comprehensive overview of the influence of donor-recipient relatedness on conjugation is still lacking, but such an overview is important to quantitatively assess the risk of plasmid transfer and the effect of interventions which limit the spread of antibiotic resistance, and to obtain parameter values for conjugation in mathematical models. Therefore, we performed a meta-analysis on reported conjugation frequencies from Escherichia coli donors to various recipient species.

RESULTS: Thirty-two studies reporting 313 conjugation frequencies for liquid broth matings and 270 conjugation frequencies for filter matings were included in our meta-analysis. The reported conjugation frequencies varied over 11 orders of magnitude. Decreasing taxonomic relatedness between donor and recipient bacteria, when adjusted for confounding factors, was associated with a lower conjugation frequency in liquid matings. The mean conjugation frequency for bacteria of the same order, the same class, and other classes was 10, 20, and 789 times lower than the mean conjugation frequency within the same species, respectively. This association between relatedness and conjugation frequency was not found for filter matings. The conjugation frequency was furthermore found to be influenced by temperature in both types of mating experiments, and in addition by plasmid incompatibility group in liquid matings, and by recipient origin and mating time in filter matings.

CONCLUSIONS: In our meta-analysis, taxonomic relatedness is limiting conjugation in liquid matings, but not in filter matings, suggesting that taxonomic relatedness is not a limiting factor for conjugation in environments where bacteria are fixed in space.

RevDate: 2020-05-27

Xu J, Bu F, Zhu W, et al (2020)

Microbial Consortiums of Hydrogenotrophic Methanogenic Mixed Cultures in Lab-Scale Ex-Situ Biogas Upgrading Systems under Different Conditions of Temperature, pH and CO.

Microorganisms, 8(5): pii:microorganisms8050772.

In this study, hydrogenotrophic methanogenic mixed cultures taken from 13 lab-scale ex-situ biogas upgrading systems under different temperature (20-70 °C), pH (6.0-8.5), and CO (0-10%, v/v) variables were systematically investigated. High-throughput 16S rRNA gene sequencing was used to identify the microbial consortia, and statistical analyses were conducted to reveal the microbial diversity, the core functional microbes, and their correlative relationships with tested variables. Overall, bacterial community was more complex than the archaea community in all mixed cultures. Hydrogenotrophic methanogens Methanothermobacter, Methanobacterium, and Methanomassiliicoccus, and putative syntrophic acetate-oxidizing bacterium Coprothermobacter and Caldanaerobacter were found to predominate, but the core functional microbes varied under different conditions. Multivariable sensitivity analysis indicated that temperature (p < 0.01) was the crucial variable to determine the microbial consortium structures in hydrogenotrophic methanogenic mixed cultures. pH (0.01 < p < 0.05) significantly interfered with the relative abundance of dominant archaea. Although CO did not affect community (p > 0.1), some potential CO-utilizing syntrophic metabolisms might be enhanced. Understanding of microbial consortia in the hydrogenotrophic methanogenic mixed cultures related to environmental variables was a great advance to reveal the microbial ecology in microbial biogas upgrading process.

RevDate: 2020-05-26

Zhang H, Zhang B, Wang S, et al (2020)

Spatiotemporal vanadium distribution in soils with microbial community dynamics at vanadium smelting site.

Environmental pollution (Barking, Essex : 1987), 265(Pt A):114782 pii:S0269-7491(20)31876-5 [Epub ahead of print].

Whereas the adverse effects of vanadium released from smelting activities on soil microbial ecology have been widely recognized, little is known about spatiotemporal vanadium distribution and microbial community dynamics in typical contaminated sites. This study describes vanadium contents associated with health risk and microbial responses in both topsoil and subsoil during four consecutive seasons around an ongoing-production smelter in Panzhihua, China. Higher levels of vanadium concentration exceeding soil background value in China (82 mg/kg) were found close to the smelter. Vanadium concentrations decreased generally with the increase in distance to the smelter and depth below surface, as soil vanadium pollution is induced mainly by atmospheric deposition of vanadium bearing dust during smelting. Residual fraction was the predominated vanadium form in soils, with pronounced increase in bioavailable vanadium during rainfall period due to frequent drought-rewetting process. Topsoil close to the smelter exhibited significant contamination, inducing high probability of adverse health effects. Spatiotemporal vanadium distribution creates filtering effects on soil microorganisms, promoting metal tolerant genera in topsoil (e.g. Microvirga) and subsoil (e.g. Bacillus, Geobacter), which is the key in maintaining the community structure by promoting cooperative relation with other taxa. Our results reveal spatiotemporal vanadium distribution in soils at site scale with potential health risk and microbial responses, which is helpful in identifying severe contamination and implementing bioremediation.

RevDate: 2020-05-26

Lourenço KS, Suleiman AKA, Pijl A, et al (2020)

Dynamics and resilience of soil mycobiome under multiple organic and inorganic pulse disturbances.

The Science of the total environment, 733:139173 pii:S0048-9697(20)32690-5 [Epub ahead of print].

Disturbances in soil can cause short-term soil changes, consequently changes in microbial community what may result in long-lasting ecological effects. Here, we evaluate how multiple pulse disturbances effect the dynamics and resilience of fungal community, and the co-occurrence of fungal and bacterial communities in a 389 days field experiment. We used soil under sugarcane cultivation as soil ecosystem model, and organic residue (vinasse - by-product of sugarcane ethanol production) combined or not with inorganic (organic residue applied 30 days before or together with mineral N fertilizer) amendments as disturbances. Application of organic residue alone as a single disturbance or 30 days prior to a second disturbance with mineral N resulted in similar changes in the fungal community. The simultaneous application of organic and mineral N as a single pulse disturbance had the greatest impact on the fungal community. Organic amendment increased the abundance of saprotrophs, fungal species capable of denitrification, and fungi described to have copiotrophic and oligotrophic lifestyles. Furthermore, the changes in the fungal community were not correlated with the changes in the bacterial community. The fungal community was neither resistant nor resilient to organic and inorganic disturbances over the one-year sampling period. Our findings provide insights on the immediate and delayed responses of the fungal community over one year to disturbance by organic and inorganic amendments.

RevDate: 2020-05-26

Nettles R, Ricks KD, RT Koide (2020)

The Dynamics of Interacting Bacterial and Fungal Communities of the Mouse Colon Following Antibiotics.

Microbial ecology pii:10.1007/s00248-020-01525-6 [Epub ahead of print].

We tested two hypotheses concerning the dynamics of intestinal microbial communities of young mice following antibiotic-induced disturbance. The first is that disturbance of the bacterial community causes disturbance of the fungal community. Our results were consistent with that hypothesis. Antibiotics significantly altered bacterial community structure. Antibiotics also altered fungal community structure, significantly increasing the relative abundance of Candida lusitaniae, a known pathogen, while simultaneously significantly decreasing the relative abundances of several other common fungal species. The result was a temporary decrease in fungal diversity. Moreover, bacterial load was negatively correlated with the relative abundances of Candida lusitaniae and Candida parapsilosis, while it was positively correlated with the relative abundances of many other fungal species. Our second hypothesis is that control mice serve as a source of probiotics capable of invading intestines of mice with disturbed microbial communities and restoring pre-antibiotic bacterial and fungal communities. However, we found that control mice did not restore disturbed microbial communities. Instead, mice with disturbed microbial communities induced disturbance in control mice, consistent with the hypothesis that antibiotic-induced disturbance represents an alternate stable state that is easier to achieve than to correct. Our results indicate the occurrence of significant interactions among intestinal bacteria and fungi and suggest that the stimulation of certain bacterial groups may potentially be useful in countering the dominance of fungal pathogens such as Candida spp. However, the stability of disturbed microbial communities could complicate recovery.

RevDate: 2020-05-26

Sichert A, Corzett CH, Schechter MS, et al (2020)

Verrucomicrobia use hundreds of enzymes to digest the algal polysaccharide fucoidan.

Nature microbiology pii:10.1038/s41564-020-0720-2 [Epub ahead of print].

Brown algae are important players in the global carbon cycle by fixing carbon dioxide into 1 Gt of biomass annually, yet the fate of fucoidan-their major cell wall polysaccharide-remains poorly understood. Microbial degradation of fucoidans is slower than that of other polysaccharides, suggesting that fucoidans are more recalcitrant and may sequester carbon in the ocean. This may be due to the complex, branched and highly sulfated structure of fucoidans, which also varies among species of brown algae. Here, we show that 'Lentimonas' sp. CC4, belonging to the Verrucomicrobia, acquired a remarkably complex machinery for the degradation of six different fucoidans. The strain accumulated 284 putative fucoidanases, including glycoside hydrolases, sulfatases and carbohydrate esterases, which are primarily located on a 0.89-megabase pair plasmid. Proteomics reveals that these enzymes assemble into substrate-specific pathways requiring about 100 enzymes per fucoidan from different species of brown algae. These enzymes depolymerize fucoidan into fucose, which is metabolized in a proteome-costly bacterial microcompartment that spatially constrains the metabolism of the toxic intermediate lactaldehyde. Marine metagenomes and microbial genomes show that Verrucomicrobia including 'Lentimonas' are abundant and highly specialized degraders of fucoidans and other complex polysaccharides. Overall, the complexity of the pathways underscores why fucoidans are probably recalcitrant and more slowly degraded, since only highly specialized organisms can effectively degrade them in the ocean.

RevDate: 2020-05-25
CmpDate: 2014-03-05

Han SI, Lee JC, Lee HJ, et al (2013)

Planifilum composti sp. nov., a thermophile isolated from compost.

International journal of systematic and evolutionary microbiology, 63(Pt 12):4557-4561.

Two thermophilic bacteria, designated strains P8(T) and P12, were isolated from compost in Korea. The isolates grew aerobically from 50 to 75 °C (optimum at 55 °C) and at pH 4.0-9.0 (optimum pH 6.5). Aerial mycelia were not observed. Single spores were produced along the substrate hypha. The predominant menaquinone was MK-7. Major fatty acids were iso-C17 : 0, iso-C15 : 0 and iso-C16 : 0. The cell wall contained meso-diaminopimelic acid and the polar lipids were phosphatidylethanolamine, an aminophospholipid and sphingoglycolipid. The DNA G+C contents were 55.9-56.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains P8(T) and P12 belonged to the genus Planifilum in the family Thermoactinomycetaceae with sequence similarities of 96.1-97.2 %. Levels of DNA-DNA relatedness between strain P8(T) and the type strains of recognized species of the genus Planifilum ranged from 28.9 to 38.2 %. On the basis of data from the present polyphasic study, strains P8(T) and P12 are considered to represent a novel species of the genus Planifilum, for which the name Planifilum composti sp. nov. is proposed. The type strain is P8(T) (= KACC 16581(T) = NBRC 108858(T)).

RevDate: 2020-05-25
CmpDate: 2014-04-29

Kim SJ, Ahn JH, Lee TH, et al (2013)

Reyranella soli sp. nov., isolated from forest soil, and emended description of the genus Reyranella Pagnier et al. 2011.

International journal of systematic and evolutionary microbiology, 63(Pt 9):3164-3167.

A Gram-stain-negative, non-motile, rod-shaped bacterial strain, designated KIS14-15(T), was isolated from forest soil of Baengnyeong Island in the Yellow Sea in Korea and its taxonomic position was investigated by using a polyphasic study. Strain KIS14-15(T) grew optimally at 30 °C, at pH 6.0-7.0 and without NaCl. In the neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, strain KIS14-15(T) formed a cluster with the strains of Reyranella massiliensis with a bootstrap resampling value of 100%. Strain KIS14-15(T) exhibited 16S rRNA gene sequence similarity values of 98.0% to R. massiliensis 521(T) and of less than 89% to the type strains of other taxa. The mean level of DNA-DNA relatedness between strain KIS14-15(T) and R. massiliensis KACC 16548(T) was 21% (reciprocal, 24%). The predominant ubiquinone found in strain KIS14-15(T) and R. massiliensis KACC 16548(T) was ubiquinone-10 (Q-10). The predominant fatty acids of strain KIS14-15(T) and R. massiliensis KACC 16548(T) were C(18:1)ω7c, C(18:1) 2-OH and 11-methyl C(18:1)ω7c. Total polar lipids of strain KIS14-15(T) were phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unknown aminolipid and one unknown lipid. Differential phenotypic properties, together with phylogenetic and genetic distinctiveness, demonstrated that strain KIS14-15(T) is distinguishable from R. massiliensis. On the basis of the data presented, strain KIS14-15(T) is considered to represent a novel species of the genus Reyranella, for which the name Reyranella soli sp. nov. is proposed. The type strain is KIS14-15(T) (= KACC 13034(T) =NBRC 108950(T)).

RevDate: 2020-05-25
CmpDate: 2013-11-19

Lee HR, Han SI, Rhee KH, et al (2013)

Mucilaginibacter herbaticus sp. nov., isolated from the rhizosphere of the medicinal plant Angelica sinensis.

International journal of systematic and evolutionary microbiology, 63(Pt 8):2787-2793.

A strictly aerobic, Gram-staining-negative, non-motile and rod-shaped bacterial strain, DR-9(T), was isolated from rhizosphere soil of the medicinal herb Angelica sinensis. Strain DR-9(T) grew at 20-40 °C, at pH 4.0-9.0 and in the presence of 0-1 % (w/v) NaCl. The major fatty acids were iso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c and/or iso-C15 : 0 2-OH), MK-7 was the major isoprenoid quinone, and phosphatidylethanolamine and an unidentified aminophospholipid were the major polar lipids. A phylogenetic tree based on 16S rRNA gene sequences showed that strain DR-9(T) formed a lineage within the genus Mucilaginibacter and was closely related to Mucilaginibacter polysacchareus DRP28(T) (96.1 % sequence similarity), Mucilaginibacter myungsuensis HMD1056(T) (95.9 % sequence similarity), Mucilaginibacter ximonensis XM-003(T) (95.8 %) and Mucilaginibacter boryungensis BDR-9(T) (95.1 %). The status of strain DR-9(T) as a representative of a separate species was confirmed by DNA hybridization, with 38.6, 36.3 and 29.9 % DNA-DNA relatedness with M. polysacchareus DRP28(T), M. ximonensis XM-003(T) and M. boryungensis BDR-9(T), respectively. The genomic DNA G+C content of strain DR-9(T) was 49.8 %. These data suggest that strain DR-9(T) should be considered as a representative of a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter herbaticus sp. nov. is proposed. The type strain is DR-9(T) (= KACC 16469(T) = NBRC 108839(T)).

RevDate: 2020-05-25
CmpDate: 2013-09-25

Kim SJ, Weon HY, Ahn JH, et al (2013)

Roseomonas aerophila sp. nov., isolated from air.

International journal of systematic and evolutionary microbiology, 63(Pt 6):2334-2337.

An aerobic, Gram-stain-negative, motile, mesophilic bacterium, designated strain 7515T-07(T), was isolated from an air sample in the Taean region, Republic of Korea. The strain grew at 4-40 °C (optimum, 30 °C) and pH 5.0-9.0 (optimum, pH 7.0). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 7515T-07(T) was related to members of the genus Roseomonas and had highest 16S rRNA gene sequence similarity with Roseomonas ludipueritiae 170/96(T) (96.7%). 16S RNA gene sequence similarity between strain 7515T-07(T) and Roseomonas gilardii ATCC 49956(T) (the type species of the genus Roseomonas) was 93.4%. Strain 7515T-07(T) contained Q-10 as the ubiquinone and C18:1ω7c and C19:0 cyclo ω8c as the dominant fatty acids (>10%). The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and two unidentified aminolipids. The DNA G+C content was 73.0 mol%. Combined data from phenotypic, phylogenetic and chemotaxonomic studies demonstrated that strain 7515T-07(T) is a representative of a novel species of the genus Roseomonas, for which the name Roseomonas aerophila sp. nov. is proposed. The type strain is 7515T-07(T) (=KACC 16529(T)=NBRC 108923(T)).

RevDate: 2020-05-25
CmpDate: 2013-06-18

Álvarez-Pérez S, Lievens B, Jacquemyn H, et al (2013)

Acinetobacter nectaris sp. nov. and Acinetobacter boissieri sp. nov., isolated from floral nectar of wild Mediterranean insect-pollinated plants.

International journal of systematic and evolutionary microbiology, 63(Pt 4):1532-1539.

The taxonomic status of 14 strains of members of the genus Acinetobacter isolated from floral nectar of wild Mediterranean insect-pollinated plants, which did not belong to any previously described species within this genus, was investigated following a polyphasic approach. Confirmation that these strains formed two separate lineages within the genus Acinetobacter was obtained from comparative analysis of the partial sequences of the 16S rRNA gene and the gene encoding the β-subunit of RNA polymerase (rpoB), DNA-DNA reassociation data, determination of the DNA G+C content and physiological tests. The names Acinetobacter nectaris sp. nov. and Acinetobacter boissieri sp. nov. are proposed. The type strain of A. nectaris sp. nov. is SAP 763.2(T) (= LMG 26958(T) = CECT 8127(T)) and that of A. boissieri sp. nov. is SAP 284.1(T) (= LMG 26959(T) = CECT 8128(T)).

RevDate: 2020-05-24
CmpDate: 2014-03-05

Vandamme P, De Brandt E, Houf K, et al (2013)

Burkholderia humi sp. nov., Burkholderia choica sp. nov., Burkholderia telluris sp. nov., Burkholderia terrestris sp. nov. and Burkholderia udeis sp. nov.: Burkholderia glathei-like bacteria from soil and rhizosphere soil.

International journal of systematic and evolutionary microbiology, 63(Pt 12):4707-4718.

Analysis of partial gyrB gene sequences revealed six taxa in a group of 17 Burkholderia glathei-like isolates which were further examined by (GTG)5-PCR fingerprinting, 16S rRNA gene sequence analysis, DNA-DNA hybridizations, determination of the DNA G+C content, whole-cell fatty acid analysis and an analysis of cell and colony morphology and more than 180 biochemical characteristics. The results demonstrated that one taxon consisting of three human clinical isolates represented Burkholderia zhejiangensis, a recently described methyl-parathion-degrading bacterium isolated from a wastewater-treatment system in China. The remaining taxa represented five novel species isolated from soil or rhizosphere soil samples, and could be distinguished by both genotypic and phenotypic characteristics. We therefore propose to formally classify these bacteria as Burkholderia humi sp. nov. (type strain, LMG 22934(T) = CCUG 63059(T)), Burkholderia choica sp. nov. (type strain, LMG 22940(T) = CCUG 63063(T)), Burkholderia telluris sp. nov. (type strain, LMG 22936(T) = CCUG 63060(T)), Burkholderia udeis sp. nov. (type strain, LMG 27134(T) = CCUG 63061(T)) and Burkholderia terrestris sp. nov. (type strain, LMG 22937(T) = CCUG 63062(T)).

RevDate: 2020-05-23

Schröer L, De Kock T, Cnudde V, et al (2020)

Differential colonization of microbial communities inhabiting Lede stone in the urban and rural environment.

The Science of the total environment, 733:139339 pii:S0048-9697(20)32856-4 [Epub ahead of print].

Air pollution is one of the main actors of stone deterioration. It influences not only the material itself but also prokaryotes colonizing rocks. Prokaryotes can affect rock substrates and biological colonization will most likely become relatively more important during the course of the 21st century. Therefore, it is necessary to understand the effects of air pollution on biological colonization and on the impact of this colonization on rock weathering. For this reason, we studied the prokaryotic community of Lede stone from two deteriorated monuments in Belgium: one in the urban and one in the rural environment. This research conducts 16S rRNA gene Next Generation Sequencing combined with an isolation campaign. It revealed diverse and complex prokaryotic communities with more specialized bacteria present in the urban environment, while archaea were barely detected. Some genera could cause biodeterioration but the isolates did not produce a significant amount of acid. Soluble salts analysis revealed an important effect of salts on the prokaryotic community. Colour measurements at least indicate that a main effect of prokaryotes might be on the aesthetics: In the countryside prokaryotic communities seemed to discolour Lede stone, while pollution most likely blackened building stones in the urban environment.

RevDate: 2020-05-23

Spielmann J, Ahmadi H, Scheepers M, et al (2020)

The two copies of the zinc and cadmium ZIP6 transporter of Arabidopsis halleri have distinct effects on cadmium tolerance.

Plant, cell & environment [Epub ahead of print].

Plants have the ability to colonize highly diverse environments. The zinc and cadmium hyperaccumulator Arabidopsis halleri has adapted to establish populations on soils covering an extreme range of metal availabilities. The A. halleri ZIP6 gene presents several hallmarks of hyperaccumulation candidate genes: it is constitutively highly expressed in roots and shoots and is associated with a zinc accumulation quantitative trait locus. Here, we show that AhZIP6 is duplicated in the A. halleri genome. The two copies are expressed mainly in the vasculature in both A. halleri and A. thaliana, indicative of conserved cis regulation, and acquired partial organ specialization. Yeast complementation assays determined that AhZIP6 is a zinc and cadmium transporter. AhZIP6 silencing in A. halleri or expression in A. thaliana alters cadmium tolerance, but has no impact on zinc and cadmium accumulation. AhZIP6-silenced plants display reduced cadmium uptake upon short-term exposure, adding AhZIP6 to the limited number of Cd transporters supported by in planta evidence. Altogether, our data suggest that AhZIP6 is key to fine-tune metal homeostasis in specific cell-types. This study additionally highlights the distinct fates of duplicated genes in A. halleri. This article is protected by copyright. All rights reserved.

RevDate: 2020-05-23

Zhang R, Li Y, Yan W, et al (2020)

Viral control of biomass and diversity of bacterioplankton in the deep sea.

Communications biology, 3(1):256 pii:10.1038/s42003-020-0974-5.

Viral abundance in deep-sea environments is high. However, the biological, ecological and biogeochemical roles of viruses in the deep sea are under debate. In the present study, microcosm incubations of deep-sea bacterioplankton (2,000 m deep) with normal and reduced pressure of viral lysis were conducted in the western Pacific Ocean. We observed a negative effect of viruses on prokaryotic abundance, indicating the top-down control of bacterioplankton by virioplankton in the deep-sea. The decreased bacterial diversity and a different bacterial community structure with diluted viruses indicate that viruses are sustaining a diverse microbial community in deep-sea environments. Network analysis showed that relieving viral pressure decreased the complexity and clustering coefficients but increased the proportion of positive correlations for the potentially active bacterial community, which suggests that viruses impact deep-sea bacterioplankton interactions. Our study provides experimental evidences of the crucial role of viruses in microbial ecology and biogeochemistry in deep-sea ecosystems.

RevDate: 2020-05-23

van Tilburg Bernardes E, Pettersen VK, Gutierrez MW, et al (2020)

Intestinal fungi are causally implicated in microbiome assembly and immune development in mice.

Nature communications, 11(1):2577 pii:10.1038/s41467-020-16431-1.

The gut microbiome consists of a multi-kingdom microbial community. Whilst the role of bacteria as causal contributors governing host physiological development is well established, the role of fungi remains to be determined. Here, we use germ-free mice colonized with defined species of bacteria, fungi, or both to differentiate the causal role of fungi on microbiome assembly, immune development, susceptibility to colitis, and airway inflammation. Fungal colonization promotes major shifts in bacterial microbiome ecology, and has an independent effect on innate and adaptive immune development in young mice. While exclusive fungal colonization is insufficient to elicit overt dextran sulfate sodium-induced colitis, bacterial and fungal co-colonization increase colonic inflammation. Ovalbumin-induced airway inflammation reveals that bacterial, but not fungal colonization is necessary to decrease airway inflammation, yet fungi selectively promotes macrophage infiltration in the airway. Together, our findings demonstrate a causal role for fungi in microbial ecology and host immune functionality, and therefore prompt the inclusion of fungi in therapeutic approaches aimed at modulating early life microbiomes.

RevDate: 2020-05-22

Murrell JC, McGenity TJ, AT Crombie (2020)

Microbial metabolism of isoprene: a much-neglected climate-active gas.

Microbiology (Reading, England) [Epub ahead of print].

The climate-active gas isoprene is the major volatile produced by a variety of trees and is released into the atmosphere in enormous quantities, on a par with global emissions of methane. While isoprene production in plants and its effect on atmospheric chemistry have received considerable attention, research into the biological isoprene sink has been neglected until recently. Here, we review current knowledge on the sources and sinks of isoprene and outline its environmental effects. Focusing on degradation by microbes, many of which are able to use isoprene as the sole source of carbon and energy, we review recent studies characterizing novel isoprene degraders isolated from soils, marine sediments and in association with plants. We describe the development and use of molecular methods to identify, quantify and genetically characterize isoprene-degrading strains in environmental samples. Finally, this review identifies research imperatives for the further study of the environmental impact, ecology, regulation and biochemistry of this interesting group of microbes.

RevDate: 2020-05-22

Des Marteaux LE, Kullik SA, Habash M, et al (2020)

Terrestrial Isopods Porcellio scaber and Oniscus asellus (Crustacea: Isopoda) Increase Bacterial Abundance and Modify Microbial Community Structure in Leaf Litter Microcosms: a Short-Term Decomposition Study.

Microbial ecology pii:10.1007/s00248-020-01527-4 [Epub ahead of print].

Invasive terrestrial isopods are likely to have altered leaf litter decomposition processes in North American forests, but the mechanisms underlying these alterations and the degree to which they differ among isopod species are poorly characterized. Using mixed-deciduous leaf litter microcosms, we quantified the effects of two common, invasive isopods (Oniscus asellus and Porcellio scaber) on short-term leaf litter decomposition and microbial community structure and function. Microcosms containing ground litter and a microbial inoculant were exposed to one of the two isopod species or no isopods for 21 days. Mass loss was then quantified as the change in litter dry mass after leaching, and microbial respiration was quantified as the mass of CO2 absorbed by soda lime. Litter leachates were plated on agar to quantify culturable bacterial and fungal abundance, and denaturing gradient gel electrophoresis of amplified leachate microbial DNA was used to characterize shifts in microbial community structure. Isopod presence increased litter mass loss by a modest ~ 6%, but did not affect litter microbial respiration. Bacterial abundance increased significantly in the presence of isopods, while fungal abundance was either unchanged or reduced. Overall litter microbial species richness was reduced by isopods, with O. asellus specifically reducing fungal abundance and diversity. Isopods modified the microbial community structure by suppressing four bacterial and one fungal species, while promoting growth of four other bacterial species (two unique to each isopod species) and two fungal species (one which was unique to O. asellus).

RevDate: 2020-05-22

Grimes DJ (2020)

The Vibrios: Scavengers, Symbionts, and Pathogens from the Sea.

Microbial ecology pii:10.1007/s00248-020-01524-7 [Epub ahead of print].

Bacteria belonging to the genus Vibrio are major carbon cycle drivers in marine and estuarine environments. As is the case for most carbon cycle participants, the vibrios metabolize degradable compounds such as sugars and amino acids; they can also degrade some more recalcitrant compounds including hydrocarbons and lignins. Several vibrios are symbionts and even fewer are pathogenic for animals, including humans and marine animals and plants. This paper reviews Vibrio ecology, metabolism, and survival, and it also discusses select vibrios-V. alginolyticus, V. cholerae, V. coralliilyticus, V. cortegadensis, V. fischeri, V. harveyi, V. harveyi var. carahariae, V. ordalii, V. parahaemolyticus, and V. vulnificus.

RevDate: 2020-05-22

Torralba MG, Kuelbs C, Moncera KJ, et al (2020)

Characterizing Microbial Signatures on Sculptures and Paintings of Similar Provenance.

Microbial ecology pii:10.1007/s00248-020-01504-x [Epub ahead of print].

The preservation of artwork challenges museums, collectors, and art enthusiasts. Currently, reducing moisture, adjusting the type of lighting, and preventing the formation of mold are primary methods to preserving and preventing deterioration. Other methods such as ones based in detailed knowledge of molecular biology such as microbial community characterization using polymerase chain reaction (PCR) and sequencing have yet to be explored. Such molecular biology approaches are essential to explore as some environmental bacteria are capable of oxidizing nonpolar chemical substances rich in hydrocarbons such as oil-based paints. Using 16S rDNA Illumina Sequencing, we demonstrate a novel finding that there are differing bacterial communities for artwork from roughly the same era when comparing paintings on wood, paintings on canvases, and sculptures made of stone and marble. We also demonstrate that there are specific genera such as Aeromonas known for having oxidase positive strains, present on paintings on wood and paintings on canvas that could potentially be responsible for deterioration and fading as such organisms produce water or hydrogen peroxide as a byproduct of cytochrome c oxidase activity. The advantages of these genomics-based approaches to characterizing the microbial population on deteriorating artwork provides immense potential by identifying potentially damaging species that may not be detected using conventional methods in addition to addressing challenges to identification, restoration, and preservation efforts.

RevDate: 2020-05-22

Zheng P, Li Y, Wu J, et al (2020)

Erratum: Perturbed Microbial Ecology in Myasthenia Gravis: Evidence from the Gut Microbiome and Fecal Metabolome.

Advanced science (Weinheim, Baden-Wurttemberg, Germany), 7(10):2001296 pii:ADVS202001296.

[This corrects the article DOI: 10.1002/advs.201901441.].

RevDate: 2020-05-22

Kirchner N, Cano-Prieto C, van der Voort M, et al (2020)

Draft Genome Sequence of Lipopeptide-Producing Strain Pseudomonas fluorescens DSM 11579 and Comparative Genomics with Pseudomonas sp. Strain SH-C52, a Closely Related Lipopeptide-Producing Strain.

Microbiology resource announcements, 9(21): pii:9/21/e00304-20.

Pseudomonas fluorescens DSM 11579 is known to be a producer of the lipopeptides brabantamide and thanamycin. Its draft genome gives insight into the complete secondary metabolite production capacity of the strain and builds the basis for a comparative study with Pseudomonas sp. strain SH-C52, a lipopeptide-producing strain involved in natural disease-suppressive soils.

RevDate: 2020-05-21

Hooban B, Joyce A, Fitzhenry K, et al (2020)

The role of the natural aquatic environment in the dissemination of extended spectrum beta-lactamase and carbapenemase encoding genes: A scoping review.

Water research, 180:115880 pii:S0043-1354(20)30417-6 [Epub ahead of print].

The natural aquatic environment is a significant contributor to the development and circulation of clinically significant antibiotic resistance genes (ARGs). The potential for the aquatic environment to act as a reservoir for ARG accumulation in areas receiving anthropogenic contamination has been thoroughly researched. However, the emergence of novel ARGs in the absence of external influences, as well as the capacity of environmental bacteria to disseminate ARGs via mobile genetic elements remain relatively unchallenged. In order to address these knowledge gaps, this scoping literature review was established focusing on the detection of two important and readily mobile ARGs, namely, extended spectrum beta-lactamase (ESBL) and carbapenemase genes. This review included 41 studies from 19 different countries. A range of different water bodies including rivers (n = 26), seawaters (n = 6) and lakes (n = 3), amongst others, were analysed in the included studies. ESBL genes were reported in 29/41 (70.7%) studies, while carbapenemase genes were reported in 13/41 (31.7%), including joint reporting in 9 studies. The occurrence of mobile genetic elements was evaluated, which included the detection of integrons (n = 22), plasmids (n = 18), insertion sequences (n = 4) and transposons (n = 3). The ability of environmental bacteria to successfully transfer resistance genes via conjugation was also examined in 11 of the included studies. The findings of this scoping review expose the presence of clinically significant ARGs in the natural aquatic environment and highlights the potential ability of environmental isolates to disseminate these genes among different bacterial species. As such, the results presented demonstrate how anthropogenic point discharges may not act as the sole contributor to the development and spread of clinically significant antibiotic resistances. A number of critical knowledge gaps in current research were also identified. Key highlights include the limited number of studies focusing on antibiotic resistance in uncontaminated aquatic environments as well as the lack of standardisation among methodologies of reviewed investigations.

RevDate: 2020-05-21

Van Landuyt J, Cimmino L, Dumolin C, et al (2020)

Microbial enrichment, functional characterization and isolation from a cold seep yields piezotolerant obligate hydrocarbon degraders.

FEMS microbiology ecology pii:5841521 [Epub ahead of print].

Deep-sea environments can become contaminated with petroleum hydrocarbons. The effects of hydrostatic pressure in the deep sea on microbial oil degradation is poorly understood. Here we performed long-term enrichments (100 days) from a natural cold seep while providing optimal conditions to sustain high hydrocarbon degradation rates. Through enrichments performed at increased hydrostatic pressure (HP) and ambient pressure (AP) and by using control enrichments with marine broth, we demonstrated that both pressure and carbon source can have a big impact on the community structure. In contrast to previous studies, hydrocarbonoclastic OTUs remained dominant at both AP and increased HP, suggesting piezotolerance of these OTUs over the tested pressure range. Twenty-three isolates were obtained after isolation and dereplication. After re-cultivation at increased HP, an Alcanivorax sp. showed promising piezotolerance in axenic culture. Furthermore, preliminary co-cultivation tests indicated synergistic growth between some isolates, which shows promise for future synthetic community construction. Overall, more insights into the effect of increased HP on oil degrading communities was obtained as well as several interesting isolates, e.g. a piezotolerant hydrocarbonoclastic bacterium for future deep-sea bioaugmentation investigation.

RevDate: 2020-05-21

Rocha KF, Kuramae EE, Borges BMF, et al (2020)

Microbial N-cycling gene abundance is affected by cover crop specie and development stage in an integrated cropping system.

Archives of microbiology pii:10.1007/s00203-020-01910-2 [Epub ahead of print].

Grasses of the Urochloa genus have been widely used in crop-livestock integration systems or as cover crops in no-till systems such as in rotation with maize. Some species of Urochloa have mechanisms to reduce nitrification. However, the responses of microbial functions in crop-rotation systems with grasses and its consequence on soil N dynamics are not well-understood. In this study, the soil nitrification potential and the abundance of ammonifying microorganisms, total bacteria and total archaea (16S rRNA gene), nitrogen-fixing bacteria (NFB, nifH), ammonia-oxidizing bacteria (AOB, amoA) and archaea (AOA, amoA) were assessed in soil cultivated with ruzigrass (Urochloa ruziziensis), palisade grass (Urochloa brizantha) and Guinea grass (Panicum maximum). The abundance of ammonifying microorganisms was not affected by ruzigrass. Ruzigrass increased the soil nitrification potential compared with palisade and Guinea grass. Ruzigrass increased the abundance of N-fixing microorganisms at the middle and late growth stages. The abundances of nitrifying microorganisms and N-fixers in soil were positively correlated with the soil N-NH4+ content. Thus, biological nitrogen fixation might be an important input of N in systems of rotational production of maize with forage grasses. The abundance of microorganisms related to ammonification, nitrification and nitrogen fixing and ammonia-oxidizing archea was related to the development stage of the forage grass.

RevDate: 2020-05-21

Minich JJ, Petrus S, Michael JD, et al (2020)

Temporal, Environmental, and Biological Drivers of the Mucosal Microbiome in a Wild Marine Fish, Scomber japonicus.

mSphere, 5(3): pii:5/3/e00401-20.

Changing ocean conditions driven by anthropogenic activities may have a negative impact on fisheries by increasing stress and disease. To understand how environment and host biology drives mucosal microbiomes in a marine fish, we surveyed five body sites (gill, skin, digesta, gastrointestinal tract [GI], and pyloric ceca) from 229 Pacific chub mackerel, Scomber japonicus, collected across 38 time points spanning 1 year from the Scripps Institution of Oceanography Pier (La Jolla, CA). Mucosal sites had unique microbial communities significantly different from the surrounding seawater and sediment communities with over 10 times more total diversity than seawater. The external surfaces of skin and gill were more similar to seawater, while digesta was more similar to sediment. Alpha and beta diversity of the skin and gill was explained by environmental and biological factors, specifically, sea surface temperature, chlorophyll a, and fish age, consistent with an exposure gradient relationship. We verified that seasonal microbial changes were not confounded by regional migration of chub mackerel subpopulations by nanopore sequencing a 14,769-bp region of the 16,568-bp mitochondria across all temporal fish specimens. A cosmopolitan pathogen, Photobacterium damselae, was prevalent across multiple body sites all year but highest in the skin, GI, and digesta between June and September, when the ocean is warmest. The longitudinal fish microbiome study evaluates the extent to which the environment and host biology drives mucosal microbial ecology and establishes a baseline for long-term surveys linking environment stressors to mucosal health of wild marine fish.IMPORTANCE Pacific chub mackerel, Scomber japonicus, are one of the largest and most economically important fisheries in the world. The fish is harvested for both human consumption and fish meal. Changing ocean conditions driven by anthropogenic stressors like climate change may negatively impact fisheries. One mechanism for this is through disease. As waters warm and chemistry changes, the microbial communities associated with fish may change. In this study, we performed a holistic analysis of all mucosal sites on the fish over a 1-year time series to explore seasonal variation and to understand the environmental drivers of the microbiome. Understanding seasonality in the fish microbiome is also applicable to aquaculture production for producers to better understand and predict when disease outbreaks may occur based on changing environmental conditions in the ocean.

RevDate: 2020-05-20

Jakubovics NS, W Shi (2020)

A New Era for the Oral Microbiome.

Journal of dental research, 99(6):595-596.

RevDate: 2020-05-20

Fu X, Li Y, Yuan Q, et al (2020)

Continental-Scale Microbiome Study Reveals Different Environmental Characteristics Determining Microbial Richness, Composition, and Quantity in Hotel Rooms.

mSystems, 5(3): pii:5/3/e00119-20.

Culture-independent microbiome surveys have been conducted in homes, hospitals, schools, kindergartens and vehicles for public transport, revealing diverse microbial distributions in built environments. However, microbiome composition and the associated environmental characteristics have not been characterized in hotel environments. We presented here the first continental-scale microbiome study of hotel rooms (n = 68) spanning Asia and Europe. Bacterial and fungal communities were described by amplicon sequencing of the 16S rRNA gene and internal transcribed spacer (ITS) region and quantitative PCR. Similar numbers of bacterial (4,344) and fungal (4,555) operational taxonomic units were identified in the same sequencing depth, but most fungal taxa showed a restricted distribution compared to bacterial taxa. Aerobic, ubiquitous bacteria dominated the hotel microbiome with compositional similarity to previous samples from building and human nasopharynx environments. The abundance of Aspergillus was negatively correlated with latitude and accounted for ∼80% of the total fungal load in seven low-latitude hotels. We calculated the association between hotel microbiome and 16 indoor and outdoor environmental characteristics. Fungal composition and absolute quantity showed concordant associations with the same environmental characteristics, including latitude, quality of the interior, proximity to the sea, and visible mold, while fungal richness was negatively associated with heavy traffic (95% confidence interval [CI] = -127.05 to -0.25) and wall-to-wall carpet (95% CI = -47.60 to -3.82). Bacterial compositional variation was associated with latitude, quality of the interior, and floor type, while bacterial richness was negatively associated with recent redecoration (95% CI -179.00 to -44.55) and mechanical ventilation (95% CI = -136.71 to -5.12).IMPORTANCE This is the first microbiome study to characterize the microbiome data and associated environmental characteristics in hotel environments. In this study, we found concordant variation between fungal compositional variation and absolute quantity and discordant variation between community variation/quantity and richness. Our study can be used to promote hotel hygiene standards and provide resource information for future microbiome and exposure studies associated with health effects in hotel rooms.

RevDate: 2020-05-19

Venturini AM, Nakamura FM, Gontijo JB, et al (2020)

Robust DNA protocols for tropical soils.

Heliyon, 6(5):e03830 pii:e03830.

Studies in the Amazon are being intensified to evaluate the alterations in the microbial communities of soils and sediments in the face of increasing deforestation and land-use changes in the region. However, since these environments present highly heterogeneous physicochemical properties, including contaminants that hinder nucleic acids isolation and downstream techniques, the development of best molecular practices is crucial. This work aimed to optimize standard protocols for DNA extraction and gene quantification by quantitative real-time PCR (qPCR) based on natural and anthropogenic soils and sediments (primary forest, pasture, Amazonian Dark Earth, and várzea, a seasonally flooded area) of the Eastern Amazon. Our modified extraction protocol increased the fluorometric DNA concentration by 48%, reaching twice the original amount for most of the pasture and várzea samples, and the 260/280 purity ratio by 15% to values between 1.8 to 2.0, considered ideal for DNA. The addition of bovine serum albumin in the qPCR reaction improved the quantification of the 16S rRNA genes of Archaea and Bacteria and its precision among technical replicates, as well as allowed their detection in previously non-amplifiable samples. It is concluded that the changes made in the protocols improved the parameters of the DNA samples and their amplification, thus increasing the reliability of microbial communities' analysis and its ecological interpretations.

RevDate: 2020-05-20

Oliveira BG, Mendes LW, Smyth EM, et al (2020)

Assessment of microbial diversity associated with CH4 emission from sugarcane vinasse storage and transportation systems.

Journal of environmental management, 269:110748 pii:S0301-4797(20)30680-0 [Epub ahead of print].

Sugarcane bioethanol has favorable energy and greenhouse gas balance, although the production process generates several residues including vinasse, which deserves attention because of its significant methane (CH4) emission during storage and transportation stages. Considering that CH4 emissions are dependent on the structure and abundance of microbial communities, we hypothesized that different vinasse transportation systems would harbor different microbial community composition, resulting in distinct CH4 patterns. To test this hypothesis, we used high-throughput 16S rRNA sequencing with real-time PCR to evaluate the composition and abundance of microorganisms in the two main systems of vinasse storage and transportation (i.e. open channels and tanks systems) in Brazil. Our results showed higher microbial diversity and CH4 emissions in channel system, especially in the uncoated section. Significant differences in microbial community structure, diversity, and abundance between the uncoated/coated open channel and tanks indicated a clear selection at taxonomic and functional levels, especially in relation to CH4 production. These responses included higher methanogens diversity in the uncoated section of the channel and are in agreement with the methanogen abundance determined by mcrA and mba genes copy number (1.5 × 107 and 4.3 × 1010) and subsequent positive correlation with CH4 emissions (R2 = 0.8). The most representative methanogen genus across the samples was Methanobrevibacter. The results observed herein shows that the use of the coating in the bottom of channels and tanks prevent the growth and development of a methanogen-related community. We concluded that the improvements in vinasse storage and transportation systems would significantly change the microbial community and reduce CH4 emissions, thereby making bioethanol a greener biofuel.

RevDate: 2020-05-19

Grajal-Puche A, Murray CM, Kearley M, et al (2020)

Microbial Assemblage Dynamics Within the American Alligator Nesting Ecosystem: a Comparative Approach Across Ecological Scales.

Microbial ecology pii:10.1007/s00248-020-01522-9 [Epub ahead of print].

Understanding the ecological processes that shape species assemblage patterns is central to community ecology. The effects of ecological processes on assemblage patterns are scale-dependent. We used metabarcoding and shotgun sequencing to determine bacterial taxonomic and functional assemblage patterns among varying defined focal scales (micro-, meso-, and macroscale) within the American alligator (Alligator mississippiensis) nesting microbiome. We correlate bacterial assemblage patterns among eight nesting compartments within and proximal to alligator nests (micro-), across 18 nests (meso-), and between 4 geographic sampling sites (macro-), to determine which ecological processes may drive bacterial assemblage patterns within the nesting environment. Among all focal scales, bacterial taxonomic and functional richness (α-diversity) did not statistically differ. In contrast, bacterial assemblage structure (β-diversity) was unique across all focal scales, whereas functional pathways were redundant within nests and across geographic sites. Considering these observed scale-based patterns, taxonomic bacterial composition may be governed by unique environmental filters and dispersal limitations relative to microbial functional attributes within the alligator nesting environment. These results advance pattern-process dynamics within the field of microbial community ecology and describe processes influencing the American alligator nest microbiome.

RevDate: 2020-05-20

Cheng CC, Duar RM, Lin X, et al (2020)

Ecological Importance of Cross-Feeding of the Intermediate Metabolite 1,2-Propanediol between Bacterial Gut Symbionts.

Applied and environmental microbiology, 86(11): pii:AEM.00190-20.

Cross-feeding based on the metabolite 1,2-propanediol has been proposed to have an important role in the establishment of trophic interactions among gut symbionts, but its ecological importance has not been empirically established. Here, we show that in vitro growth of Lactobacillus reuteri (syn. Limosilactobacillus reuteri) ATCC PTA 6475 is enhanced through 1,2-propanediol produced by Bifidobacterium breve UCC2003 and Escherichia coli MG1655 from the metabolization of fucose and rhamnose, respectively. Work with isogenic mutants showed that the trophic interaction is dependent on the pduCDE operon in L. reuteri, which encodes the ability to use 1,2-propanediol, and the l-fucose permease (fucP) gene in B. breve, which is required for 1,2-propanediol formation from fucose. Experiments in gnotobiotic mice revealed that, although the pduCDE operon bestows a fitness burden on L. reuteri ATCC PTA 6475 in the mouse digestive tract, the ecological performance of the strain was enhanced in the presence of B. breve UCC2003 and the mucus-degrading species Bifidobacterium bifidum The use of the respective pduCDE and fucP mutants of L. reuteri and B. breve in the mouse experiments indicated that the trophic interaction was specifically based on 1,2-propanediol. Overall, our work established the ecological importance of cross-feeding relationships based on 1,2-propanediol for the fitness of a bacterial symbiont in the vertebrate gut.IMPORTANCE Through experiments in gnotobiotic mice that employed isogenic mutants of bacterial strains that produce (Bifidobacterium breve) and utilize (Lactobacillus reuteri) 1,2-propanediol, this study provides mechanistic insight into the ecological ramifications of a trophic interaction between gut symbionts. The findings improve our understanding on how cross-feeding influences the competitive fitness of L. reuteri in the vertebrate gut and revealed a putative selective force that shaped the evolution of the species. The findings are relevant since they provide a basis to design rational microbial-based strategies to modulate gut ecosystems, which could employ mixtures of bacterial strains that establish trophic interactions or a personalized approach based on the ability of a resident microbiota to provide resources for the incoming microbe.

RevDate: 2020-05-19
CmpDate: 2014-06-25

Lee HJ, KS Whang (2014)

Streptomyces graminisoli sp. nov. and Streptomyces rhizophilus sp. nov., isolated from bamboo (Sasa borealis) rhizosphere soil.

International journal of systematic and evolutionary microbiology, 64(Pt 5):1546-1551.

Four strains of actinomycete, designated strains JR-19T, JR-12, JR-29 and JR-41T were isolated from bamboo (Sasa borealis) rhizosphere soil. Phylogenetic, morphological, chemotaxonomic and phenotypic analysis demonstrated that the four strains belong to the genus Streptomyces. Microscopic observation revealed that the four strains produced spirales spore chains with spiny surfaces. The cell-wall peptidoglycan of the four strains contained ll-diaminopimelic acid, glutamic acid, alanine and glycine. Whole-cell hydrolysates mainly contained glucose and ribose. The predominant menaquinones were MK-9 (H6) and MK-9 (H8). Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that these strains and the members of the genus Streptomyces exhibited moderately high 16S rRNA gene sequence similarities of 98.3-99.3%, with the most closely related strains being Streptomyces shenzhenensis 172115T and Streptomyces gramineus JR-43T. Based on the phenotypic and genotypic data, the four strains are considered to represent two novel species of the genus Streptomyces, for which the names Streptomyces graminisoli sp. nov. [to accommodate strains JR-19T (type strain; =KACC 16472T=NBRC 108883T), JR-12 (=KACC 16471) and JR-29 (=KACC 16473)] and Streptomyces rhizophilus sp. nov. [for strain JR-41T (=KACC 16580T=NBRC 108885T)] are proposed.

RevDate: 2020-05-18

Xing J, Jia X, Wang H, et al (2020)

The legacy of bacterial invasions on soil native communities.

Environmental microbiology [Epub ahead of print].

Soil microbial communities are often not resistant to the impact caused by microbial invasions, both in terms of structure and functionality, but it remains unclear whether these changes persist over time. Here we used 3 strains of Escherichia coli O157:H7 (E. coli O157:H7), a species used for modelling bacterial invasions, to evaluate the resilience of the bacterial communities from four Chinese soils to invasion. The impact of E. coli O157:H7 strains on soil native communities was tracked for 120 days by analysing bacterial community composition as well as their metabolic potential. We showed that soil native communities were not resistant to invasion, as demonstrated by a decline in bacterial diversity and shifts in bacterial composition in all treatments. The resilience of native bacterial communities (diversity and composition) was inversely correlated with invader's persistence in soils (R2 = 0.487, P < 0.001). Microbial invasions also impacted the functionality of the soil communities (niche breadth and community niche), the degree of resilience being dependent on soil or native community diversity. Collectively, our results indicate that bacteria invasions can potentially leave a footprint in the structure and functionality of soil communities, indicating the need of assessing the legacy of introducing exotic species in soil environments. This article is protected by copyright. All rights reserved.

RevDate: 2020-05-17

Gallego S, Barkay T, NL Fahrenfeld (2020)

Tagging the vanA gene in wastewater microbial communities for cell sorting and taxonomy of vanA carrying cells.

The Science of the total environment, 732:138865 pii:S0048-9697(20)32382-2 [Epub ahead of print].

Failure to understand the microbial ecology driving the proliferation of antibiotic resistance in the environment prevents us from developing strategies to limit the spread of antibiotic resistant infectious disease. In this study, we developed for the first time a tyramide signal amplification-fluorescence in situ hybridization-fluorescence-activated cell sorting protocol (TSA-FISH-FACS) for the characterization of all vanA carrying bacteria in wastewater samples. Firstly, we validated the TSA-FISH protocol through microscopy in pure cultures and wastewater influent. Then, samples were sorted and quantified by FACS and qPCR. Significantly higher percentage tagging of cells was detected in vanA carrying pure cultures and wastewater samples spiked with vanA carrying cells as compared to vanA negative Gram positive strains and non-spiked wastewater samples respectively. qPCR analysis targeting vanZ, a regulating gene in the vanA cluster, showed its relative abundance was significantly greater in Enterococcus faecium ATCC 700221-spiked and positively sorted samples compared to the E. faecium spiked and negatively sorted samples. Phylogenetic analysis was then performed. Although further efforts are needed to overcome technical problems, we have, for the first time, demonstrated sorting bacterial-cells carrying antibiotic resistance genes from wastewater samples through a TSA-FISH-FACS protocol and provided insight into the microbial ecology of vancomycin resistant bacteria. Future potential applications using this approach will include the separation of members of an environmental microbial community (cultured and hard-to-culture) to allow for metagenomics on single cells or, in the case of clumping, targeting a smaller portion of the community with a priori knowledge that the target gene is present.

RevDate: 2020-05-16

Pajares S, Varona-Cordero F, DU Hernández-Becerril (2020)

Spatial Distribution Patterns of Bacterioplankton in the Oxygen Minimum Zone of the Tropical Mexican Pacific.

Microbial ecology pii:10.1007/s00248-020-01508-7 [Epub ahead of print].

Microbial communities within oxygen minimum zones (OMZs) are crucial drivers of marine biogeochemical cycles; however, we still lack an understanding of how these communities are distributed across an OMZ. We explored vertical (from 5 to 500 m depth) and horizontal (coast to open ocean) distribution of bacterioplankton and its relationships with the main oceanographic conditions in three transects of the tropical Mexican Pacific OMZ. The distribution of the microbial diversity and the main clades changed along the transition from oxygen-rich surface water to the OMZ core, demonstrating the sensitivity of key bacterial groups to deoxygenation. The euphotic zone was dominated by Synechococcales, followed by Flavobacteriales, Verrucomicrobiales, Rhodobacterales, SAR86, and Cellvibrionales, whereas the OMZ core was dominated by SAR11, followed by SAR406, SAR324, SAR202, UBA10353 marine group, Thiomicrospirales and Nitrospinales. The marked environmental gradients along the water column also supported a high potential for niche partitioning among OMZ microorganisms. Additionally, in the OMZ core, bacterial assemblages from the same water mass were more similar to each other than those from another water mass. There were also important differences between coastal and open-ocean communities: Flavobacteriales, Verrucomicrobiales, Rhodobacterales, SAR86, and Cellvibrionales were more abundant in coastal areas, while Synechococcales, SAR406, SAR324, SAR202, UBA10353 marine group, and Thiomicrospirales were more abundant in the open ocean. Our results suggest a biogeographic structure of the bacterioplankton in this OMZ region, with limited community mixing across water masses, except in upwelling events, and little dispersion of the community by currents in the euphotic zone.

RevDate: 2020-05-16

Jiang W, Wang Y, Luo J, et al (2020)

Antimicrobial peptide GH12 prevents dental caries by regulating dental plaque microbiota.

Applied and environmental microbiology pii:AEM.00527-20 [Epub ahead of print].

Due to the complex microecology and microenvironment of dental plaque, novel caries prevention strategies require modulating the microbial communities ecologically and reducing the cariogenic properties effectively. Antimicrobial peptide GH12 reduced the lactic acid production and exopolysaccharides (EPS) synthesis of the Streptococcus mutans biofilm and the three-species biofilm in vitro in the previous studies. However, the anticaries effects and microecological effects of GH12 remained to be investigated in the complex biofilm model in vitro and the animal caries model in vivo In the present study, GH12 at 64 mg/mL showed the most effective inhibition on lactic acid production, EPS synthesis, pH decline and biofilm integrity of the human dental plaque-derived multispecies biofilms in vitro, and GH12 at 64 mg/L was therefore chosen for subsequent assays in vitro and in vivo When treated with 64 mg/L GH12, the dental plaque-derived multispecies biofilms sampled from the healthy volunteers maintained the microbial diversity and showed a similar microbial community structure to the control group. In the rat caries model with a caries-promoting diet, 64 mg/L GH12 regulated the microbiota of dental plaque, where the abundance of caries-associated bacteria was decreased and the abundance of commensal bacteria was increased. In addition, 64 mg/L GH12 significantly reduced the caries scores of sulcal and smooth surface caries in all locations. In conclusion, GH12 could inhibit the cariogenic properties of dental plaque without perturbing the dental plaque microbiota of healthy individuals, and GH12 could regulate the dysbiotic microbial ecology and arrest caries development under cariogenic conditions.Importance The anticaries effects and microecological regulation effects of antimicrobial peptide GH12 were evaluated systematically in vitro and in vivo GH12 inhibited the cariogenic virulence of dental plaque without over-intervening in the microbial ecology of healthy individuals in vitro GH12 regulated the microbial ecology of dental plaque to a certain extent in vivo under cariogenic conditions, increased the proportion of commensal bacteria, and decreased the abundance of caries-associated bacteria. GH12 could significantly suppress the incidence and severity of dental caries in vivo This study provided an alternative antimicrobial therapy for the treatment of dental caries.

RevDate: 2020-05-16

Kuramae EE, Derksen S, Schlemper TR, et al (2020)

Sorghum Growth Promotion by Paraburkholderia tropica and Herbaspirillum frisingense: Putative Mechanisms Revealed by Genomics and Metagenomics.

Microorganisms, 8(5): pii:microorganisms8050725.

Bacteria from the genera Paraburkholderia and Herbaspirillum can promote the growth of Sorghum bicolor, but the underlying mechanisms are not yet known. In a pot experiment, sorghum plants grown on sterilized substrate were inoculated with Paraburkholderia tropica strain IAC/BECa 135 and Herbaspirillumfrisingense strain IAC/BECa 152 under phosphate-deficient conditions. These strains significantly increased Sorghum bicolor cultivar SRN-39 root and shoot biomass. Shotgun metagenomic analysis of the rhizosphere revealed successful colonization by both strains; however, the incidence of colonization was higher in plants inoculated with P. tropica strain IAC/BECa 135 than in those inoculated with H. frisingense strain IAC/BECa 152. Conversely, plants inoculated with H. frisingense strain IAC/BECa 152 showed the highest increase in biomass. Genomic analysis of the two inoculants implied a high degree of rhizosphere fitness of P. tropica strain IAC/BECa 135 through environmental signal processing, biofilm formation, and nutrient acquisition. Both genomes contained genes related to plant growth-promoting bacterial (PGPB) traits, including genes related to indole-3-acetate (IAA) synthesis, nitrogen fixation, nodulation, siderophore production, and phosphate solubilization, although the P. tropica strain IAC/BECa 135 genome contained a slightly more extensive repertoire. This study provides evidence that complementary mechanisms of growth promotion in Sorghum might occur, i.e., that P. tropica strain IAC/BECa 135 acts in the rhizosphere and increases the availability of nutrients, while H. frisingense strain IAC/BECa 152 influences plant hormone signaling. While the functional and taxonomic profiles of the rhizobiomes were similar in all treatments, significant differences in plant biomass were observed, indicating that the rhizobiome and the endophytic microbial community may play equally important roles in the complicated plant-microbial interplay underlying increased host plant growth.

RevDate: 2020-05-16
CmpDate: 2014-06-25

Zhang YQ, Lee JC, Park DJ, et al (2014)

Roseivivax roseus sp. nov., an alphaproteobacterium isolated from a solar saltern soil sample.

International journal of systematic and evolutionary microbiology, 64(Pt 5):1743-1746.

A pink, Gram-stain-negative, motile, halotolerant bacterium with subpolar flagellum, designated strain BH87090T, was isolated from a saline soil sample collected from the south-west coastal area of South Korea (125° 58' 58.08″ E 34° 45' 37.32″ N). The isolate formed opaque pink to red colonies on marine agar plates at 30 °C. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, sulfoquinovosyl diacylglycerol, phosphatidylcholine and one unidentified phospholipid. The sole respiratory quinone was ubiquinone-10 (Q-10). The major cellular fatty acids were C18:1ω7c, C19:0 cyclo ω8c, C16:0 and 11-methyl C18:1ω7c. The genomic DNA G+C content was 61.8 mol%. These chemotaxonomic characteristics were all consistent with specific properties of the genus Roseivivax. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate affiliated to the cluster with members of the genus Roseivivax in the Roseobacter clade, which suggested that the strain belonged to the genus Roseivivax. However, the low 16S rRNA gene similarities (93.5-95.3%) of strain BH87090T with all the members of the genus Roseivivax indicated that it represented a novel species of the genus Roseivivax. On the basis of phenotypic and genotypic data, strain BH87090T should be classified as a novel species of the genus Roseivivax. The name Roseivivax roseus sp. nov. is proposed, with strain BH87090T (=DSM 23042T=KCTC 22650T) as the type strain.

RevDate: 2020-05-16
CmpDate: 2014-06-25

Han SI, Lee JC, Ohta H, et al (2014)

Sphingomonas oligoaromativorans sp. nov., an oligotrophic bacterium isolated from a forest soil.

International journal of systematic and evolutionary microbiology, 64(Pt 5):1679-1684.

A halo- and organo-sensitive oligotrophic bacterium, designated strain SY-6T, was isolated from humus forest soil at Gyeryong mountain in Korea. Cells of the strain were Gram-negative, strictly aerobic, non-motile rods and the strain formed yellow-pigmented colonies on 100-fold-diluted nutrient broth. Strain SY-6T grew at pH 6.0-7.0 (optimal growth at pH 7.0), at 10-37 °C (optimal growth at 28 °C) and at salinities of 0-0.5% (w/v) NaCl, growing optimally at 0.01% (w/v) NaCl. On the basis of 16S rRNA gene sequence analysis, strain SY-6T was shown to belong to the genus Sphingomonas and showed the closest phylogenetic similarity to Sphingomonas polyaromaticivorans B2-7T (96.7%). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and sphingoglycolipid. The predominant ubiquinone and polyamine were Q-10 and sym-homospermidine, respectively. The major fatty acids were C18:1ω7c and C16:0. The DNA G+C content of the novel isolate was 65.3 mol%. On the basis of the evidence from this polyphasic study, strain SY-6T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas oligoaromativorans sp. nov. is proposed. The type strain is SY-6T (=KACC 12948T=NBRC 105508T).

RevDate: 2020-05-15

Barbosa RG, Sleutels T, Verstraete W, et al (2020)

Hydrogen oxidizing bacteria are capable of removing orthophosphate to ultra-low concentrations in a fed batch reactor configuration.

Bioresource technology, 311:123494 pii:S0960-8524(20)30766-5 [Epub ahead of print].

This paper proposes the use of hydrogen oxidizing bacteria (HOB) for the removal of orthophosphate from surface water as treatment step to prevent cyanobacterial blooms. To be effective as an orthophosphate removal strategy, an efficient transfer of hydrogen to the HOB is essential. A trickling filter was selected for this purpose. Using this system, a removal rate of 11.32 ± 0.43 mg PO4-3-P/L.d was achieved. The HOB biomass, developed on the trickling filter, is composed of 1.25% phosphorus on dry matter, which suggests that the orthophosphate removal principle is based on HOB growth. Cyanobacterial growth assays of the untreated and treated water showed that Synechocystis sp was only able to grow in the untreated water. Orthophosphate was removed to average residual values of 0.008 mg/L. In this proof of principle study, it is shown that HOB are able to remove orthophosphate from water to concentrations that prevent cyanobacterial growth.

RevDate: 2020-05-15

Durán-Viseras A, Andrei AŞ, Vera-Gargallo B, et al (2020)

Culturomics-based genomics sheds light on the ecology of the new haloarchaeal genus Halosegnis.

Environmental microbiology [Epub ahead of print].

The development of culture-independent techniques has revolutioned our understanding of microbial ecology, especially through the illustration of the vast gap between the environmentally abundant microbial diversity and that accessible through cultivation. However, culture-based approaches are not only crucial for understanding the evolutionary, metabolic and ecological milieu of microbial diversity, but also for the development of novel biotechnological applications. In this study, we used a culturomics-based approach in order to isolate novel microbial taxa from hypersaline environments (i.e. Isla Cristina and Isla Bacuta salterns in Huelva, Spain). We managed to obtain axenic cultures of four haloarchaeal strains that belong to a new haloarchaeal genus, and to obtain their genomic sequences. The phylogenomic and phylogenetic analyses (together with AAI, ANI and digital DDH indices) showed that the isolates constitute two new species, for which we propose the names Halosegnis longus sp. nov. and Halosegnis rubeus sp. nov. The genomic-based metabolic reconstructions indicated that members of this new haloarchaeal genus have photoheterotrophic aerobic lifestyle with a typical salt-in signature. 16S rRNA gene sequence reads abundance profiles and genomic recruitment analyses revealed that the Halosegnis genus has a worldwide geographical distribution, reaching high abundance (up to 8%) in habitats with intermediate salinities. This article is protected by copyright. All rights reserved.

RevDate: 2020-05-15

Qureshi SS, Kedo M, ST Berthrong (2020)

Gender-neutral bathroom surfaces recolonized by microbes more quickly than single gender bathrooms.

Letters in applied microbiology [Epub ahead of print].

As humans become increasingly urban and spend more time inside the built environment, there will be increased interactions between the humans and shared public surface microbiomes. Recent cultural changes in the United States have led to increases gender-neutral bathrooms. Given that bathroom surfaces are frequently sanitized, we used this increased availability of gender-neutral bathrooms to examine how single or gender-neutral surfaces are recolonized with microbes. Given that male and female microbiomes vary, we hypothesized that rates of recolonization would differ between male, female, and gender-neutral bathroom surfaces. We collected swabs from common hand contacted surfaces in bathrooms and cultured microbes on selective and rich media to determine microbial abundance after cleaning. Recolonization was dominated by gram positive bacteria and was slowest on male, intermediate on female, and fastest on gender-neutral surfaces. These results imply that gender-neutral surfaces approach normal climax microbial communities more quickly than single gender bathrooms.

RevDate: 2020-05-15

Šimoliūnienė M, Tumėnas D, Kvederavičiūtė K, et al (2020)

Complete Genome Sequence of Bacillus cereus Bacteriophage vB_BceS_KLEB30-3S.

Microbiology resource announcements, 9(20): pii:9/20/e00348-20.

In this study, we present the genomic characterization of the temperate bacteriophage vB_BceS_KLEB30-3S (KLEB30-3S), which was induced from Bacillus cereus strain KR3M-30, isolated from a gypsum karst lake ecosystem in Lithuania. The 37,134-bp genome of KLEB30-3S contains 58 predicted protein-encoding genes and no tRNA genes.

RevDate: 2020-05-15

Köstlbacher S, Michels S, Siegl A, et al (2020)

Draft Genome Sequences of Chlamydiales Bacterium STE3 and Neochlamydia sp. Strain AcF84, Endosymbionts of Acanthamoeba spp.

Microbiology resource announcements, 9(20): pii:9/20/e00220-20.

Chlamydiales bacterium STE3 and Neochlamydia sp. strain AcF84 are obligate intracellular symbionts of Acanthamoeba spp. isolated from the biofilm of a littoral cave wall and gills from striped tiger leaf fish, respectively. We report the draft genome sequences of these two environmental chlamydiae affiliated with the family Parachlamydiaceae.

RevDate: 2020-05-14

Zwart MP, SF Elena (2020)

Modeling multipartite virus evolution: the genome formula facilitates rapid adaptation to heterogeneous environments†.

Virus evolution, 6(1):veaa022 pii:veaa022.

Multipartite viruses have two or more genome segments, and package different segments into different particle types. Although multipartition is thought to have a cost for virus transmission, its benefits are not clear. Recent experimental work has shown that the equilibrium frequency of viral genome segments, the setpoint genome formula (SGF), can be unbalanced and host-species dependent. These observations have reinvigorated the hypothesis that changes in genome-segment frequencies can lead to changes in virus-gene expression that might be adaptive. Here we explore this hypothesis by developing models of bipartite virus infection, leading to a threefold contribution. First, we show that the SGF depends on the cellular multiplicity of infection (MOI), when the requirements for infection clash with optimizing the SGF for virus-particle yield per cell. Second, we find that convergence on the SGF is very rapid, often occurring within a few cellular rounds of infection. Low and intermediate MOIs lead to faster convergence on the SGF. For low MOIs, this effect occurs because of the requirements for infection, whereas for intermediate MOIs this effect is also due to the high levels of variation generated in the genome formula (GF). Third, we explored the conditions under which a bipartite virus could outcompete a monopartite one. As the heterogeneity between environments and specificity of gene-expression requirements for each environment increased, the bipartite virus was more likely to outcompete the monopartite virus. Under some conditions, changes in the GF helped to exclude the monopartite competitor, highlighting the versatility of the GF. Our results show the inextricable relationship between MOI and the SGF, and suggest that under some conditions, the cost of multipartition can be outweighed by its benefits for the rapid tuning of viral gene expression.

RevDate: 2020-05-14

Pascual-García A, T Bell (2020)

Community-level signatures of ecological succession in natural bacterial communities.

Nature communications, 11(1):2386 pii:10.1038/s41467-020-16011-3.

A central goal in microbial ecology is to simplify the extraordinary biodiversity that inhabits natural environments into ecologically coherent units. We profiled (16S rRNA sequencing) > 700 semi-aquatic bacterial communities while measuring their functional capacity when grown in laboratory conditions. This approach allowed us to investigate the relationship between composition and function excluding confounding environmental factors. Simulated data allowed us to reject the hypothesis that stochastic processes were responsible for community assembly, suggesting that niche effects prevailed. Consistent with this idea we identified six distinct community classes that contained samples collected from distant locations. Structural equation models showed there was a functional signature associated with each community class. We obtained a more mechanistic understanding of the classes using metagenomic predictions (PiCRUST). This approach allowed us to show that the classes contained distinct genetic repertoires reflecting community-level ecological strategies. The ecological strategies resemble the classical distinction between r- and K-strategists, suggesting that bacterial community assembly may be explained by simple ecological mechanisms.

RevDate: 2020-05-14
CmpDate: 2014-03-31

Lee HJ, KS Whang (2014)

Streptomyces graminilatus sp. nov., isolated from bamboo litter.

International journal of systematic and evolutionary microbiology, 64(Pt 2):528-532.

A Gram-stain-positive, novel actinobacterium, designated strain JL-6(T), was isolated from the litter of a bamboo (Sasa borealis) forest in Damyang, Korea. Strain JL-6(T) had white-grey, smooth, cylindrical spores that were borne in straight, long spore-chains. The novel strain grew aerobically at 15-28 °C (optimum, 28 °C), pH 4.0-8.0 (optimum, pH 5.5) and with 0-1.5% (w/v) NaCl. The cell-wall peptidoglycan contained ll-diaminopimelic acid, glutamic acid, alanine and glycine. The predominant menaquinones were MK-9(H6) and MK-9(H8). Whole-cell hydrolysates mainly contained glucose and ribose. Phosphatidylinositol and phosphatidylcholine were the diagnostic phospholipids. The G+C content of the genomic DNA was 72.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JL-6(T) belonged to the genus Streptomyces with sequence similarities ranging from 97.3% to 98.3%. However, DNA-DNA hybridization between JL-6(T) and the closest related strain, Streptomyces turgidiscabies, ATCC 700248(T) and other closely related species in the genus Streptomyces showed <50% relatedness. Based on these observations, strain JL-6(T) is proposed to represent a novel species of the genus Streptomyces, for which the name Streptomyces graminilatus sp. nov. is proposed. The type strain is JL-6(T) (= KACC 16470(T) = NBRC 108882(T)).

RevDate: 2020-05-14
CmpDate: 2014-03-31

Whang KS, Lee JC, Lee HR, et al (2014)

Terriglobus tenax sp. nov., an exopolysaccharide-producing acidobacterium isolated from rhizosphere soil of a medicinal plant.

International journal of systematic and evolutionary microbiology, 64(Pt 2):431-437.

An exopolysaccharide-producing bacterium, designated strain DRP 35(T), was isolated from the rhizosphere soil of a medicinal herb, Angelica sinensis, at Geumsan in Korea. Cells were Gram-staining-negative, non-motile, catalase-positive and oxidase-negative short rods. The isolate grew aerobically from 15 to 45 °C (optimum 30 °C), pH 3.5-7.0 (optimum pH 5.0) and in the presence of 0-1.0% (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain DRP 35(T) belongs to the genus Terriglobus in the phylum Acidobacteria with a sequence similarity of 97.2% and 97.0% to Terriglobus saanensis SP1PR4(T) and Terriglobus roseus KBS63(T), respectively. The genomic DNA G+C content was 62.1 mol%. DNA-DNA relatedness between strain DRP 35(T) and the type strains of the other species of the genus Terriglobus, T. saanensis SP1PR4(T) and T. roseus KBS63(T), were 24.6 and 17.2%, respectively. The predominant menaquinone was MK-8. Major fatty acids were iso-C(15 : 0), C(16 : 1)ω7c and C(16 : 0). The polar lipids were phosphatidylethanolamine, unidentified aminophospholipid and unknown phospholipids. On the basis of polyphasic analysis from this study, strain DRP 35(T) represents a novel species of the genus Terriglobus for which the name Terriglobus tenax sp. nov. is proposed. The type strain is DRP 35(T) (= KACC 16474(T) = NBRC 109677(T)).

RevDate: 2020-05-14
CmpDate: 2014-03-25

Han SI, Lee HJ, KS Whang (2014)

Chitinophaga polysaccharea sp. nov., an exopolysaccharide-producing bacterium isolated from the rhizoplane of Dioscorea japonica.

International journal of systematic and evolutionary microbiology, 64(Pt 1):55-59.

A novel strain designated MRP-15(T), belonging to the class Sphingobacteriia (phylum Bacteroidetes), was isolated from the rhizoplane of Dioscorea japonica in South Korea and was characterized taxonomically using a polyphasic approach. The strain was found to comprise Gram-stain-negative, aerobic, non-motile, non-spore-forming rods. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain belonged to the genus Chitinophaga but was clearly separated from established species of the genus Chitinophaga. 16S rRNA gene sequence similarities between strain MRP-15(T) and type strains of established species of the genus Chitinophaga ranged from 90.3 to 97.8 %. Phenotypic and chemotaxonomic data (major menaquinone, MK-7; major fatty acids, iso-C15 : 0 and C16 : 1ω5c) supported the affiliation of strain MRP-15(T) with the genus Chitinophaga. Therefore strain MRP-15(T) represents a novel species of the genus Chitinophaga, for which the name Chitinophaga polysaccharea sp. nov. is proposed. The type strain is MRP-15(T) (= KACC 17184(T) = NCAIMB 02530(T)).

RevDate: 2020-05-13

Mahú I, Barateiro A, Rial-Pensado E, et al (2020)

Brain-Sparing Sympathofacilitators Mitigate Obesity without Adverse Cardiovascular Effects.

Cell metabolism pii:S1550-4131(20)30195-9 [Epub ahead of print].

Anti-obesity drugs in the amphetamine (AMPH) class act in the brain to reduce appetite and increase locomotion. They are also characterized by adverse cardiovascular effects with origin that, despite absence of any in vivo evidence, is attributed to a direct sympathomimetic action in the heart. Here, we show that the cardiac side effects of AMPH originate from the brain and can be circumvented by PEGylation (PEGyAMPH) to exclude its central action. PEGyAMPH does not enter the brain and facilitates SNS activity via theβ2-adrenoceptor, protecting mice against obesity by increasing lipolysis and thermogenesis, coupled to higher heat dissipation, which acts as an energy sink to increase energy expenditure without altering food intake or locomotor activity. Thus, we provide proof-of-principle for a novel class of exclusively peripheral anti-obesity sympathofacilitators that are devoid of any cardiovascular and brain-related side effects.

RevDate: 2020-05-13

Brunel C, Da Silva AF, R Gros (2020)

Environmental Drivers of Microbial Functioning in Mediterranean Forest Soils.

Microbial ecology pii:10.1007/s00248-020-01518-5 [Epub ahead of print].

Mediterranean forests own distinct characteristics resulting from climate, soil, and vegetation that affect soil microbial communities' assembly and their associated functions. We initiated a multi-scalar analysis of environmental drivers of soil functioning to (1) identify pertinent factorial scales and (2) determine the relative importance of soil, vegetation, and geoclimate influences in shaping soil microbial functions across the French Mediterranean forests. Soil samples (0-15 cm) were collected from 60 forest sites and soil physicochemical and microbiological properties were assessed across different factorial scales i.e., bioclimates, slope exposures, and forest stands. Patterns in microbial catabolic potential (i.e., extracellular enzymes and microbial respiration) and carbon (C) source utilization (i.e., catabolic-level physiological profiling) were partitioned between vegetation cover, soil characteristics, and geoclimate components. Our results reveal that the catabolic potential of soil microbes was strongly influenced by the forest stands and mainly relied on ammonium and nitrate contents. In contrast, variation in C source utilization was mainly explained by vegetation cover. Soil metabolic capacities of microorganisms and resulting C dynamics were largely constrained by climate parameters, which suggests potentially important consequences for soil C storage. Our study revealed diverse structuration patterns between the catabolic potential and the carbon source utilization of soil microbial communities, and gives insights into the underlying mechanisms of soil microbial functioning in Mediterranean forests.

RevDate: 2020-05-13

Mohr AE, Jäger R, Carpenter KC, et al (2020)

The athletic gut microbiota.

Journal of the International Society of Sports Nutrition, 17(1):24 pii:10.1186/s12970-020-00353-w.

The microorganisms in the gastrointestinal tract play a significant role in nutrient uptake, vitamin synthesis, energy harvest, inflammatory modulation, and host immune response, collectively contributing to human health. Important factors such as age, birth method, antibiotic use, and diet have been established as formative factors that shape the gut microbiota. Yet, less described is the role that exercise plays, particularly how associated factors and stressors, such as sport/exercise-specific diet, environment, and their interactions, may influence the gut microbiota. In particular, high-level athletes offer remarkable physiology and metabolism (including muscular strength/power, aerobic capacity, energy expenditure, and heat production) compared to sedentary individuals, and provide unique insight in gut microbiota research. In addition, the gut microbiota with its ability to harvest energy, modulate the immune system, and influence gastrointestinal health, likely plays an important role in athlete health, wellbeing, and sports performance. Therefore, understanding the mechanisms in which the gut microbiota could play in the role of influencing athletic performance is of considerable interest to athletes who work to improve their results in competition as well as reduce recovery time during training. Ultimately this research is expected to extend beyond athletics as understanding optimal fitness has applications for overall health and wellness in larger communities. Therefore, the purpose of this narrative review is to summarize current knowledge of the athletic gut microbiota and the factors that shape it. Exercise, associated dietary factors, and the athletic classification promote a more "health-associated" gut microbiota. Such features include a higher abundance of health-promoting bacterial species, increased microbial diversity, functional metabolic capacity, and microbial-associated metabolites, stimulation of bacterial abundance that can modulate mucosal immunity, and improved gastrointestinal barrier function.

RevDate: 2020-05-13

Colquhoun C, Duncan M, G Grant (2020)

Inflammatory Bowel Diseases: Host-Microbial-Environmental Interactions in Dysbiosis.

Diseases (Basel, Switzerland), 8(2): pii:diseases8020013.

Crohn's Disease (CD) and Ulcerative Colitis (UC) are world-wide health problems in which intestinal dysbiosis or adverse functional changes in the microbiome are causative or exacerbating factors. The reduced abundance and diversity of the microbiome may be a result of a lack of exposure to vital commensal microbes or overexposure to competitive pathobionts during early life. Alternatively, many commensal bacteria may not find a suitable intestinal niche or fail to proliferate or function in a protective/competitive manner if they do colonize. Bacteria express a range of factors, such as fimbriae, flagella, and secretory compounds that enable them to attach to the gut, modulate metabolism, and outcompete other species. However, the host also releases factors, such as secretory IgA, antimicrobial factors, hormones, and mucins, which can prevent or regulate bacterial interactions with the gut or disable the bacterium. The delicate balance between these competing host and bacteria factors dictates whether a bacterium can colonize, proliferate or function in the intestine. Impaired functioning of NOD2 in Paneth cells and disrupted colonic mucus production are exacerbating features of CD and UC, respectively, that contribute to dysbiosis. This review evaluates the roles of these and other the host, bacterial and environmental factors in inflammatory bowel diseases.

RevDate: 2020-05-12

Herren CM (2020)

Disruption of cross-feeding interactions by invading taxa can cause invasional meltdown in microbial communities.

Proceedings. Biological sciences, 287(1927):20192945.

The strength of biotic interactions within an ecological community affects the susceptibility of the community to invasion by introduced taxa. In microbial communities, cross-feeding is a widespread type of biotic interaction that has the potential to affect community assembly and stability. Yet, there is little understanding of how the presence of cross-feeding within a community affects invasion risk. Here, I develop a metabolite-explicit model where native microbial taxa interact through both cross-feeding and competition for metabolites. I use this model to study how the strength of biotic interactions, especially cross-feeding, influence whether an introduced taxon can join the community. I found that stronger cross-feeding and competition led to much lower invasion risk, as both types of biotic interactions lead to greater metabolite scarcity for the invader. I also evaluated the impact of a successful invader on community composition and structure. The effect of invaders on the native community was greatest at intermediate levels of cross-feeding; at this 'critical' level of cross-feeding, successful invaders generally cause decreased diversity, decreased productivity, greater metabolite availability, and decreased quantities of metabolites exchanged among taxa. Furthermore, these changes resulting from a successful primary invader made communities further susceptible to future invaders. The increase in invasion risk was greatest when the network of metabolite exchange between taxa was minimally redundant. Thus, this model demonstrates a case of invasional meltdown that is mediated by initial invaders disrupting the metabolite exchange networks of the native community.

RevDate: 2020-05-12

Paula CCP, Bichuette ME, MHR Seleghim (2020)

Nutrient availability in tropical caves influences the dynamics of microbial biomass.

MicrobiologyOpen [Epub ahead of print].

Few studies have evaluated the trophic level in tropical caves, and none related the microbial biomass dynamics in the immobilization of carbon and nitrogen. Here, four tropical caves of Terra Ronca State Park, Brazil, were studied: Angélica, São Bernardo, Terra Ronca I, and Terra Ronca II caves. Physical, chemical, and microbiological parameters (microbial biomass and respiration) were estimated in the dry and wet seasons. São Bernardo, Terra Ronca I, and Terra Ronca II caves presented higher nitrogen and microbial biomass nitrogen (MBN) values in the wet season than in the dry season. On the other hand, the Angélica cave showed larger amounts of nitrogen and lower MBN values in the dry season. These results indicate that caves can be adjusted in two ecological theories known as "stoichiometric decomposition" and "microbial nitrogen mining"-to the effects of nutrient availability on organic matter decomposition. The caves studied showed different environmental dynamics in relation to organic matter decomposition, which allows them to be considered unique and possess specific characteristics. Microbial biomass dynamics can be an important parameter to evaluate the availability of nutrients and ecological dynamics of the trophic network in subterranean environments.

RevDate: 2020-05-12

Koh H, N Zhao (2020)

A powerful microbial group association test based on the higher criticism analysis for sparse microbial association signals.

Microbiome, 8(1):63 pii:10.1186/s40168-020-00834-9.

BACKGROUND: In human microbiome studies, it is crucial to evaluate the association between microbial group (e.g., community or clade) composition and a host phenotype of interest. In response, a number of microbial group association tests have been proposed, which account for the unique features of the microbiome data (e.g., high-dimensionality, compositionality, phylogenetic relationship). These tests generally fall in the class of aggregation tests which amplify the overall group association by combining all the underlying microbial association signals, and, therefore, they are powerful when many microbial species are associated with a given host phenotype (i.e., low sparsity). However, in practice, the microbial association signals can be highly sparse, and this is especially the situation where we have a difficulty to discover the microbial group association.

METHODS: Here, we introduce a powerful microbial group association test for sparse microbial association signals, namely, microbiome higher criticism analysis (MiHC). MiHC is a data-driven omnibus test taken in a search space spanned by tailoring the higher criticism test to incorporate phylogenetic information and/or modulate sparsity levels and including the Simes test for excessively high sparsity levels. Therefore, MiHC robustly adapts to diverse phylogenetic relevance and sparsity levels.

RESULTS: Our simulations show that MiHC maintains a high power at different phylogenetic relevance and sparsity levels with correct type I error controls. We also apply MiHC to four real microbiome datasets to test the association between respiratory tract microbiome and smoking status, the association between the infant's gut microbiome and delivery mode, the association between the gut microbiome and type 1 diabetes status, and the association between the gut microbiome and human immunodeficiency virus status.

CONCLUSIONS: In practice, the true underlying association pattern on the extent of phylogenetic relevance and sparsity is usually unknown. Therefore, MiHC can be a useful analytic tool because of its high adaptivity to diverse phylogenetic relevance and sparsity levels. MiHC can be implemented in the R computing environment using our software package freely available at

RevDate: 2020-05-12
CmpDate: 2016-05-10

Lee HJ, KS Whang (2015)

Streptomyces sasae sp. nov., isolated from bamboo (Sasa borealis) rhizosphere soil.

International journal of systematic and evolutionary microbiology, 65(10):3547-3551.

A novel strain of Gram-staining-positive actinobacterium, designated strain JR-39T, was isolated from the rhizosphere soil of bamboo (Sasa borealis) sampled in Damyang, Korea, and its taxonomic position was investigated by a polyphasic approach. The isolate formed flexuous chains of spores that were cylindrical and smooth-surfaced. Strain JR-39T grew at 4–37 °C (optimum 28 °C). The pH range for growth was pH 5–10 (optimum pH 6–8) and the NaCl range for growth was 0–5 % (w/v) with optimum growth at 1 % NaCl. The cell-wall peptidoglycan contained ll-diaminopimelic acid, glutamic acid, alanine and glycine. Whole-cell hydrolysates mainly contained glucose, mannose, ribose and rhamnose. Predominant menaquinones were MK-9 (H6), MK-9 (H8) and MK-9 (H4). The major cellular fatty acids were anteiso-C15 : 0, iso-C16 : 0, iso-C15 : 0 and iso-C14 : 0. The G+C content of the DNA was 72.3 ± 0.34 mol%. Phylogenetic analyses based on 16S rRNA gene sequence analysis indicated that strain JR-39T belonged to the genus Streptomyces, showing the highest sequence similarity to Streptomyces panaciradicis 1MR-8T (99.4 %), Streptomyces capoamus JCM 4734T (98.8 %), Streptomyces galbus DSM 40089T (98.7 %), Streptomyces longwoodensis LMG 20096T (98.7 %), Streptomyces bungoensis NBRC 15711T (98.7 %) and Streptomyces rhizophilus JR-41T (98.7 %). However, DNA–DNA hybridization assays, as well as physiological and biochemical analyses, showed that strain JR-39T could be differentiated from its closest phylogenetic relatives. On the basis of the phenotypic and genotypic characteristics, strain JR-39T represents a novel species for which the name Streptomyces sasae sp. nov. is proposed. The type strain is JR-39T (= KACC 17182T = NBRC 109809T).

RevDate: 2020-05-11

He J, Xu S, Zhang B, et al (2020)

Gut microbiota and metabolite alterations associated with reduced bone mineral density or bone metabolic indexes in postmenopausal osteoporosis.

Aging, 12: pii:103168 [Epub ahead of print].

Reduced bone mineral density (BMD) is associated with an altered microbiota in senile osteoporosis. However, the relationship among gut microbiota, BMD and bone metabolic indexes remains unknown in postmenopausal osteoporosis. In this study, fecal microbiota profiles for 106 postmenopausal individuals with osteopenia (n=33) or osteoporosis (n=42) or with normal BMD (n=31) were determined. An integrated 16S rRNA gene sequencing and LC-MS-based metabolomics approach was applied to explore the association of estrogen-reduced osteoporosis with the gut microbiota and fecal metabolic phenotype. Adjustments were made using several statistical models for potential confounding variables identified from the literature. The results demonstrated decreased bacterial richness and diversity in postmenopausal osteoporosis. Additionally, showed significant differences in abundance levels among phyla and genera in the gut microbial community were found. Moreover, postmenopausal osteopenia-enriched N-acetylmannosamine correlated negatively with BMD, and distinguishing metabolites were closely associated with gut bacterial variation. Both serum procollagen type I N propeptide (P1NP) and C-terminal telopeptide of type I collagen (CTX-1) correlated positively with osteopenia-enriched Allisonella, Klebsiella and Megasphaera. However, we did not find a significant correlation between bacterial diversity and estrogen. These observations will lead to a better understanding of the relationship between bone homeostasis and the microbiota in postmenopausal osteoporosis.

RevDate: 2020-05-11

Obolski U, Perez PN, Villabona-Arenas CJ, et al (2019)

MVSE: An R-package that estimates a climate-driven mosquito-borne viral suitability index.

Methods in ecology and evolution, 10(8):1357-1370.

Viruses, such as dengue, Zika, yellow fever and chikungunya, depend on mosquitoes for transmission. Their epidemics typically present periodic patterns, linked to the underlying mosquito population dynamics, which are known to be driven by natural climate fluctuations. Understanding how climate dictates the timing and potential of viral transmission is essential for preparedness of public health systems and design of control strategies. While various alternative approaches have been proposed to estimate local transmission potential of such viruses, few open-source, ready to use and freely available software tools exist.We developed the Mosquito-borne Viral Suitability Estimator (MVSE) software package for the R programming environment. MVSE estimates the index P, a novel suitability index based on a climate-driven mathematical expression for the basic reproductive number of mosquito-borne viruses. By accounting for local humidity and temperature, as well as viral, vector and human priors, the index P can be estimated for specific host and viral species in different regions of the globe.We describe the background theory, empirical support and biological interpretation of the index P. Using real-world examples spanning multiple epidemiological contexts, we further demonstrate MVSE's basic functionality, research and educational potentials.

RevDate: 2020-05-11

Samad MS, Lee HJ, Cerbin S, et al (2020)

Niche Differentiation of Host-Associated Pelagic Microbes and Their Potential Contribution to Biogeochemical Cycling in Artificially Warmed Lakes.

Frontiers in microbiology, 11:582.

It has been proposed that zooplankton-associated microbes provide numerous beneficial services to their "host". However, there is still a lack of understanding concerning the effect of temperature on the zooplankton microbiome. Furthermore, it is unclear to what extent the zooplankton microbiome differs from free-living and particle-associated (PA) microbes. Here, we explicitly addressed these issues by investigating (1) the differences in free-living, PA, and zooplankton associated microbes and (2) the impact of temperature on these microbes in the water column of a series of lakes artificially warmed by two power plants. High-throughput amplicon sequencing of the 16S rRNA gene showed that diversity and composition of the bacterial community associated to zooplankton, PA, and bacterioplankton varied significantly from one another, grouping in different clusters indicating niche differentiation of pelagic microbes. From the abiotic parameters measured, temperature significantly affected the diversity and composition of all analyzed microbiomes. Two phyla (e.g., Proteobacteria and Bacteroidetes) dominated in zooplankton microbiomes whereas Actinobacteria was the dominant phylum in the bacterioplankton. The microbial species richness and diversity was lower in zooplankton compared to bacterioplankton and PA. Surprisingly, genera of methane-oxidizing bacteria, methylotrophs and nitrifiers (e.g., Nitrobacter) significantly associated with the microbiome of zooplankton and PA. Our study clearly demonstrates niche differentiation of pelagic microbes and their potential link to biogeochemical cycling in freshwater systems.

RevDate: 2020-05-11

Araújo CAS, Ferreira PC, Pupin B, et al (2020)

Osmotolerance as a determinant of microbial ecology: A study of phylogenetically diverse fungi.

Fungal biology, 124(5):273-288.

Osmotic stress induced by high solute concentration can prevent fungal metabolism and growth due to alterations in properties of the cytosol, changes in turgor, and the energy required to synthesize and retain compatible solutes. We used germination to quantify tolerance/sensitivity to the osmolyte KCl (0.1-4.5 M, in 0.1 M increments) for 71 strains (40 species) of ecologically diverse fungi. These include 11 saprotrophic species (17 strains, including two xerophilic species), five mycoparasitic species (five strains), six plant-pathogenic species (13 strains), and 19 entomopathogenic species (36 strains). A dendrogram obtained from cluster analyses, based on KCl inhibitory concentrations 50 % and 90 % calculated by Probit Analysis, revealed three groups of fungal isolates accordingly to their osmotolerance. The most-osmotolerant group (Group 3) contained the majority of saprotrophic fungi, and Aspergillus niger (F19) was the most tolerant. The highly xerophilic Aspergillus montevidense and Aspergillus pseudoglaucus were the second- and third-most tolerant species, respectively. All Aspergillus and Cladosporium species belonged to Group 3, followed by the entomopathogens Colletotrichum fioriniae, Simplicillium lanosoniveum, and Trichothecium roseum. Group 2 exhibited a moderate osmotolerance, and included plant-pathogens such as Colletotrichum and Fusarium, mycoparasites such as Clonostachys spp, some saprotrophs such as Mucor and Penicillium spp., and some entomopathogens such as Isaria, Lecanicillium, Mariannaea, Simplicillium, and Torrubiella. Group 1 contained the osmo-sensitive strains: the rest of the entomopathogens and the mycoparasitic Gliocladium and Trichoderma. Although stress tolerance did not correlate with their primary ecological niche, classification of these 71 fungal strains was more closely aligned with their ecology than with their phylogenetic relatedness. We discuss the implications for both microbial ecology and fungal taxonomy.

RevDate: 2020-05-10

Seward J, Carson MA, Lamit LJ, et al (2020)

Peatland Microbial Community Composition Is Driven by a Natural Climate Gradient.

Microbial ecology pii:10.1007/s00248-020-01510-z [Epub ahead of print].

Peatlands are important players in climate change-biosphere feedbacks via long-term net carbon (C) accumulation in soil organic matter and as potential net C sources including the potent greenhouse gas methane (CH4). Interactions of climate, site-hydrology, plant community, and groundwater chemical factors influence peatland development and functioning, including C dioxide (CO2) and CH4 fluxes, but the role of microbial community composition is not well understood. To assess microbial functional and taxonomic dissimilarities, we used high throughput sequencing of the small subunit ribosomal DNA (SSU rDNA) to determine bacterial and archaeal community composition in soils from twenty North American peatlands. Targeted DNA metabarcoding showed that although Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla on average, intermediate and rich fens hosted greater diversity and taxonomic richness, as well as an array of candidate phyla when compared with acidic and nutrient-poor poor fens and bogs. Moreover, pH was revealed to be the strongest predictor of microbial community structure across sites. Predictive metagenome content (PICRUSt) showed increases in specific genes, such as purine/pyrimidine and amino-acid metabolism in mid-latitude peatlands from 38 to 45° N, suggesting a shift toward utilization of microbial biomass over utilization of initial plant biomass in these microbial communities. Overall, there appears to be noticeable differences in community structure between peatland classes, as well as differences in microbial metabolic activity between latitudes. These findings are in line with a predicted increase in the decomposition and accelerated C turnover, and suggest that peatlands north of 37° latitude may be particularly vulnerable to climate change.

RevDate: 2020-05-10

Gnanasekaran G (2020)

Correction to: Disappearance of Quorum Sensing in Burkholderia Glumae During Experimental Evolution.

Following the publication of this article [1], authors Jae Yun Lim and Ingyu Hwang have stated that they were not aware of, nor were they involved in the drafting, submission, or revision of this manuscript.

RevDate: 2020-05-09

Loos BG, TE Van Dyke (2020)

The role of inflammation and genetics in periodontal disease.

Periodontology 2000, 83(1):26-39.

Periodontitis is a complex disease: (a) various causative factors play a role simultaneously and interact with each other; and (b) the disease is episodic in nature, and bursts of disease activity can be recognized, ie, the disease develops and cycles in a nonlinear fashion. We recognize that various causative factors determine the immune blueprint and, consequently, the immune fitness of a subject. Normally, the host lives in a state of homeostasis or symbiosis with the oral microbiome; however, disturbances in homeostatic balance can occur, because of an aberrant host response (inherited and/or acquired during life). This imbalance results from hyper- or hyporesponsiveness and/or lack of sufficient resolution of inflammation, which in turn is responsible for much of the disease destruction seen in periodontitis. The control of this destruction by anti-inflammatory processes and proresolution processes limits the destruction to the tissues surrounding the teeth. The local inflammatory processes can also become systemic, which in turn affect organs such as the heart. Gingival inflammation also elicits changes in the ecology of the subgingival environment providing optimal conditions for the outgrowth of gram-negative, anaerobic species, which become pathobionts and can propagate periodontal inflammation and can further negatively impact immune fitness. The factors that determine immune fitness are often the same factors that determine the response to the resident biofilm, and are clustered as follows: (a) genetic and epigenetic factors; (b) lifestyle factors, such as smoking, diet, and psychosocial conditions; (c) comorbidities, such as diabetes; and (d) local and dental factors, as well as randomly determined factors (stochasticity). Of critical importance are the pathobionts in a dysbiotic biofilm that drive the viscious cycle. Focusing on genetic factors, currently variants in at least 65 genes have been suggested as being associated with periodontitis based on genome-wide association studies and candidate gene case control studies. These studies have found pleiotropy between periodontitis and cardiovascular diseases. Most of these studies point to potential pathways in the pathogenesis of periodontal disease. Also, most contribute to a small portion of the total risk profile of periodontitis, often limited to specific racial and ethnic groups. To date, 4 genetic loci are shared between atherosclerotic cardiovascular diseases and periodontitis, ie, CDKN2B-AS1(ANRIL), a conserved noncoding element within CAMTA1 upstream of VAMP3, PLG, and a haplotype block at the VAMP8 locus. The shared genes suggest that periodontitis is not causally related to atherosclerotic diseases, but rather both conditions are sequelae of similar (the same?) aberrant inflammatory pathways. In addition to variations in genomic sequences, epigenetic modifications of DNA can affect the genetic blueprint of the host responses. This emerging field will yield new valuable information about susceptibility to periodontitis and subsequent persisting inflammatory reactions in periodontitis. Further studies are required to verify and expand our knowledge base before final cause and effect conclusions about the role of inflammation and genetic factors in periodontitis can be made.

RevDate: 2020-05-09

Cockburn CF, Gregory BRB, Nasser NA, et al (2020)

Intra-Lake Arcellinida (Testate Lobose Amoebae) Response to Winter De-icing Contamination in an Eastern Canada Road-Side "Salt Belt" Lake.

Microbial ecology pii:10.1007/s00248-020-01513-w [Epub ahead of print].

Salt contamination of lakes, due to the application of winter de-icing salts on roads, presents a significant environmental challenge in the "salt belt" region of eastern North America. The research reported here presents the first deployment of a previously published proxy tool based on Arcellinida (testate lobose amoebae) for monitoring road salt contamination. The research was conducted at Silver Lake in Eastern Ontario, a 4-km-long lake with the heavily traveled Trans-Canada Highway (HWY 7) transiting the entire southern shore. The lake showed elevated conductivity (297-310 μS/cm) and sub-brackish conditions (0.14-0.15 ppt). Sodium levels were also elevated near the roadside (median Na = 1020 ppm). Cluster analysis and nonmetric multidimensional scaling results revealed four distinct Arcellinida assemblages: "Stressed Cool Water Assemblage (SCWA)," "Deep Cold Water Assemblage (DCWA)," both from below the 8-m thermocline, and the shallower water "Shallow Water Assemblage 1 (SWA-1)" and "Shallow Water Assemblage 2 (SWA-2)". Redundancy analysis showed a minor response of Arcellinida to road salt contamination in shallower areas of the lake, with confounding variables significantly impacting assemblage distribution, particularly beneath the thermocline (e.g., water temperature, water depth, sediment runoff from catchment [Ti], sediment geochemistry [Ca, S]). The results of this study indicate that the trophic structure of the lake has to date only been modestly impacted by the cumulative nature of road salt contamination. Nonetheless, the Silver Lake results should be considered of concern and warrant continued arcellinidan biomonitoring to gauge the ongoing and long-term effects of road salt on its ecosystem.

RevDate: 2020-05-09

Vences A, Abushattal S, Matanza XM, et al (2020)

Highly Transferable pAQU-Related Plasmids Encoding Multidrug Resistance Are Widespread in the Human and Fish Pathogen Photobacterium damselae subsp. damselae in Aquaculture Areas in the Black Sea.

Microbial ecology pii:10.1007/s00248-020-01519-4 [Epub ahead of print].

The marine bacterium Photobacterium damselae subsp. damselae is a pathogen that causes disease in diverse marine animals, and is also a serious opportunistic human pathogen that can cause fatal infections. Strains of this pathogen isolated from diseased European sea bass in aquaculture facilities in the Turkish coast of the Black Sea were found to exhibit reduced sensitivity to multiple antimicrobials. Selected representative strains were subjected to complete genome sequencing and plasmid characterization. It was found that multidrug resistant (MDR) isolates harboured large conjugative plasmids sharing part of their sequence backbone with pAQU-group plasmids, hitherto reported exclusively in China and Japan. Four new pAQU-group versions of plasmids were identified in the present study, containing distinct combinations of the resistance determinants tetB, floR, sul2, qnrVC, dfrA and strAB. Conjugative transfer of pPHDD2-OG2, a representative plasmid of 170,998 bp, occurred at high frequencies (2.2 × 10-2 transconjugants per donor cell), to E. coli and to pathogenic P. damselae subsp. damselae and subsp. piscicida strains. Upon transfer, pPHDD2-OG2 conferred reduced susceptibility to a number of antimicrobials to the recipient strains. Comparative genomics analysis of host strains suggested that these MDR plasmids of the pAQU-group were acquired by different genetic lineages of Pdd. This study provides evidence that P. damselae subsp. damselae isolated from diseased fish constitute a reservoir for conjugative MDR pAQU-group plasmids in the Mediterranean basin, and have the potential to spread to diverse bacterial species.

RevDate: 2020-05-09

Glaub A, Huptas C, Neuhaus K, et al (2020)

Recommendations for bacterial ribosome profiling experiments based on bioinformatic evaluation of published data.

The Journal of biological chemistry pii:RA119.012161 [Epub ahead of print].

Ribosome profiling (RIBO-Seq) has improved our understanding of bacterial translation, including finding many unannotated genes. However, protocols for RIBO-Seq and corresponding data analysis are not yet standardized. Here, we analyzed 48 RIBO-Seq samples from 9 studies of Escherichia coli K12 grown in LB medium and particularly focused on the size-selection step. We show that for conventional expression analysis, a size range between 22 and 30 nucleotides is sufficient to obtain protein-coding fragments, which has the advantage of removing many unwanted rRNA and tRNA reads. More specific analyses may require longer reads and a corresponding improvement in rRNA/tRNA depletion. There is no consensus about the appropriate sequencing depth for RIBO-Seq experiments in prokaryotes, and studies vary significantly in total read number. Our analysis suggests that 20 million reads that are not mapping to rRNA/tRNA are required for global detection of translated annotated genes. We also highlight the influence of drug-induced ribosome stalling, which causes bias at translation start sites. The resulting accumulation of reads at the start site may be especially useful for detecting weakly expressed genes. As different methods suit different questions, it may not be possible to produce a "one-size-fits-all" ribosome profiling dataset. Therefore, experiments should be carefully designed in light of the scientific questions of interest. We propose some basic characteristics that should be reported with any new RIBO-Seq datasets. Careful attention to the factors discussed should improve prokaryotic gene detection and the comparability of ribosome profiling datasets.

RevDate: 2020-05-09

Kazou M, Tzamourani A, Panagou EZ, et al (2020)

Unraveling the Microbiota of Natural Black cv. Kalamata Fermented Olives through 16S and ITS Metataxonomic Analysis.

Microorganisms, 8(5): pii:microorganisms8050672.

Kalamata natural black olives are one of the most economically important Greek varieties. The microbial ecology of table olives is highly influenced by the co-existence of bacteria and yeasts/fungi, as well as the physicochemical parameters throughout the fermentation. Therefore, the aim of this study was the identification of bacterial and yeast/fungal microbiota of both olives and brines obtained from 29 cv. Kalamata olive samples industrially fermented in the two main producing geographical regions of Greece, namely Aitoloakarnania and Messinia/Lakonia. The potential microbial biogeography association between certain taxa and geographical area was also assessed. The dominant bacterial family identified in olive and brine samples from both regions was Lactobacillaceae, presenting, however, higher average abundances in the samples from Aitoloakarnania compared to Messinia/Lakonia. At the genus level, Lactobacillus, Celerinatantimonas, Propionibacterium and Pseudomonas were the most abundant. In addition, the yeasts/fungal communities were less diverse compared to those of bacteria, with Pichiaceae being the dominant family and Pichia, Ogataea, and Saccharomyces being the most abundant genera. To the best of our knowledge, this is the first report on the microbiota of both olives and brines of cv. Kalamata black olives fermented on an industrial scale between two geographical regions of Greece using metagenomics analysis.

RevDate: 2020-05-08

Floudas D, Bentzer J, Ahrén D, et al (2020)

Uncovering the hidden diversity of litter-decomposition mechanisms in mushroom-forming fungi.

The ISME journal pii:10.1038/s41396-020-0667-6 [Epub ahead of print].

Litter decomposing Agaricales play key role in terrestrial carbon cycling, but little is known about their decomposition mechanisms. We assembled datasets of 42 gene families involved in plant-cell-wall decomposition from seven newly sequenced litter decomposers and 35 other Agaricomycotina members, mostly white-rot and brown-rot species. Using sequence similarity and phylogenetics, we split the families into phylogroups and compared their gene composition across nutritional strategies. Subsequently, we used Raman spectroscopy to examine the ability of litter decomposers, white-rot fungi, and brown-rot fungi to decompose crystalline cellulose. Both litter decomposers and white-rot fungi share the enzymatic cellulose decomposition, whereas brown-rot fungi possess a distinct mechanism that disrupts cellulose crystallinity. However, litter decomposers and white-rot fungi differ with respect to hemicellulose and lignin degradation phylogroups, suggesting adaptation of the former group to the litter environment. Litter decomposers show high phylogroup diversity, which is indicative of high functional versatility within the group, whereas a set of white-rot species shows adaptation to bulk-wood decomposition. In both groups, we detected species that have unique characteristics associated with hitherto unknown adaptations to diverse wood and litter substrates. Our results suggest that the terms white-rot fungi and litter decomposers mask a much larger functional diversity.

RevDate: 2020-05-08

Zheng Y, Hu X, Jia Z, et al (2020)

Co-occurrence patterns among prokaryotes across an age gradient in pit mud of Chinese strong-flavor liquor.

Canadian journal of microbiology [Epub ahead of print].

It is widely believed that the quality and characteristics of Chinese strong-flavor liquor (CSFL) are closely related to the age of the pit mud; CSFL produced from older pit mud tastes better. This study aimed to investigate the alteration and interaction of prokaryotic communities across an age gradient in pit mud. Prokaryotic microbes in different-aged pit mud (1, 6, and 10 years old) were analyzed by Illumina MiSeq sequencing of the 16S rRNA gene. Analysis of the 16S rRNA gene indicated that the prokaryotic community was significantly altered with pit mud age. There was a significant increase in the genera Methanosarcina, Methanobacterium, and Aminobacterium with increased age of pit mud, while the genus Lactobacillus showed a significant decreasing trend. Network analysis demonstrated that both synergetic co-occurrence and niche competition were dominated by 68 prokaryotic genera. These genera formed 10 hubs of co-occurrence patterns, mainly under the phyla Firmicutes, Euryarchaeota, and Bacteroidetes, playing important roles on ecosystem stability of the pit mud. Environmental variables (pH, NH4+, available P, available K, and Ca2+) correlated significantly with prokaryotic community assembly. The interaction of prokaryotic communities in the pit mud ecosystem and the relationship among prokaryotic communities and environmental factors contribute to the higher quality of the pit mud in older fermentation pits.

RevDate: 2020-05-07

Hicks LC, Leizeaga A, Rousk K, et al (2020)

Simulated rhizosphere deposits induce microbial N-mining that may accelerate shrubification in the subarctic.

Ecology [Epub ahead of print].

Climate change is exposing high-latitude systems to warming and a shift towards more shrub-dominated plant communities, resulting in increased leaf-litter inputs at the soil surface, and more labile root-derived organic matter (OM) input in the soil profile. Labile OM can stimulate the mineralization of soil organic matter (SOM); a phenomenon termed "priming". In N-poor subarctic soils, it is hypothesized that microorganisms may "prime" SOM in order to acquire N ("microbial N-mining"). Increased leaf-litter inputs with a high C/N ratio might further exacerbate microbial N demand, and increase the susceptibility of N-poor soils to N-mining. We investigated the N-control of SOM mineralization by amending soils from climate change simulation treatments in the subarctic (+1.1°C warming, birch litter addition, willow litter addition, and fungal sporocarp addition) with labile OM either in the form of glucose (labile C; equivalent to 400 µg C g-1 fwt soil) or alanine (labile C + N; equivalent to 400 µg C and 157 µg N g-1 fwt soil), to simulate rhizosphere inputs. Surprisingly, we found that despite five-years of simulated climate change treatments, there were no significant effects of the field-treatments on microbial process rates, community structure or responses to labile OM. Glucose primed the mineralization of both C and N from SOM, but gross mineralization of N was stimulated more than that of C, suggesting that microbial SOM-use increased in magnitude and shifted to components richer in N (i.e. selective microbial N-mining). The addition of alanine also resulted in priming of both C and N mineralization, but the N mineralization stimulated by alanine was greater than that stimulated by glucose, indicating strong N-mining even when a source of labile OM including N was supplied. Microbial carbon use efficiency was reduced in response to both labile OM inputs. Overall, these findings suggest that shrub-expansion could fundamentally alter biogeochemical cycling in the subarctic, yielding more N available for plant uptake in these N-limited soils, thus driving positive plant-soil feedbacks.

RevDate: 2020-05-07

Masteling R, Voorhoeve L, IJsselmuiden J, et al (2020)

DiSCount: computer vision for automated quantification of Striga seed germination.

Plant methods, 16:60 pii:602.

Background: Plant parasitic weeds belonging to the genus Striga are a major threat for food production in Sub-Saharan Africa and Southeast Asia. The parasite's life cycle starts with the induction of seed germination by host plant-derived signals, followed by parasite attachment, infection, outgrowth, flowering, reproduction, seed set and dispersal. Given the small seed size of the parasite (< 200 μm), quantification of the impact of new control measures that interfere with seed germination relies on manual, labour-intensive counting of seed batches under the microscope. Hence, there is a need for high-throughput assays that allow for large-scale screening of compounds or microorganisms that adversely affect Striga seed germination.

Results: Here, we introduce DiSCount (Digital Striga Counter): a computer vision tool for automated quantification of total and germinated Striga seed numbers in standard glass fibre filter assays. We developed the software using a machine learning approach trained with a dataset of 98 manually annotated images. Then, we validated and tested the model against a total dataset of 188 manually counted images. The results showed that DiSCount has an average error of 3.38 percentage points per image compared to the manually counted dataset. Most importantly, DiSCount achieves a 100 to 3000-fold speed increase in image analysis when compared to manual analysis, with an inference time of approximately 3 s per image on a single CPU and 0.1 s on a GPU.

Conclusions: DiSCount is accurate and efficient in quantifying total and germinated Striga seeds in a standardized germination assay. This automated computer vision tool enables for high-throughput, large-scale screening of chemical compound libraries and biological control agents of this devastating parasitic weed. The complete software and manual are hosted at and the archived version is available at Zenodo with the DOI 10.5281/zenodo.3627138. The dataset used for testing is available at Zenodo with the DOI 10.5281/zenodo.3403956.

RevDate: 2020-05-07

Rifkin RF, Vikram S, Ramond JB, et al (2020)

Multi-proxy analyses of a mid-15th century Middle Iron Age Bantu-speaker palaeo-faecal specimen elucidates the configuration of the 'ancestral' sub-Saharan African intestinal microbiome.

Microbiome, 8(1):62 pii:10.1186/s40168-020-00832-x.

BACKGROUND: The archaeological incidence of ancient human faecal material provides a rare opportunity to explore the taxonomic composition and metabolic capacity of the ancestral human intestinal microbiome (IM). Here, we report the results of the shotgun metagenomic analyses of an ancient South African palaeo-faecal specimen.

METHODS: Following the recovery of a single desiccated palaeo-faecal specimen from Bushman Rock Shelter in Limpopo Province, South Africa, we applied a multi-proxy analytical protocol to the sample. The extraction of ancient DNA from the specimen and its subsequent shotgun metagenomic sequencing facilitated the taxonomic and metabolic characterisation of this ancient human IM.

RESULTS: Our results indicate that the distal IM of the Neolithic 'Middle Iron Age' (c. AD 1460) Bantu-speaking individual exhibits features indicative of a largely mixed forager-agro-pastoralist diet. Subsequent comparison with the IMs of the Tyrolean Iceman (Ötzi) and contemporary Hadza hunter-gatherers, Malawian agro-pastoralists and Italians reveals that this IM precedes recent adaptation to 'Western' diets, including the consumption of coffee, tea, chocolate, citrus and soy, and the use of antibiotics, analgesics and also exposure to various toxic environmental pollutants.

CONCLUSIONS: Our analyses reveal some of the causes and means by which current human IMs are likely to have responded to recent dietary changes, prescription medications and environmental pollutants, providing rare insight into human IM evolution following the advent of the Neolithic c. 12,000 years ago. Video Abtract.

RevDate: 2020-05-06

Zannoni A, Pietra M, Gaspardo A, et al (2020)

Non-invasive Assessment of Fecal Stress Biomarkers in Hunting Dogs During Exercise and at Rest.

Frontiers in veterinary science, 7:126.

Intense exercise causes to organisms to have oxidative stress and inflammation at the gastrointestinal (GI) level. The reduction in intestinal blood flow and the exercise-linked thermal damage to the intestinal mucosa can cause intestinal barrier disruption, followed by an inflammatory response. Furthermore, the adaptation to exercise may affect the gut microbiota and the metabolome of the biofluids. The aim of the present research was to evaluate the presence of a GI derangement in hunting dogs through a non-invasive sampling as a consequence of a period of intense exercise in comparison with samples collected at rest. The study included nine dogs that underwent the same training regime for hunting wild boar. In order to counterbalance physiological variations, multiple-day replicates were collected and pooled at each experimental point for each dog. The samples were collected immediately at rest before the training (T0), after 60 days of training (T1), after 60 days of hunting wild boar (T2), and finally, at 60 days of rest after hunting (T3). A number of potential stress markers were evaluated: fecal cortisol metabolites (FCMs) as a major indicator of altered physiological states, immunoglobulin A (IgA) as an indicator of intestinal immune protection, and total antioxidant activity [total antioxidant capacity (TAC)]. Since stool samples contain exfoliated cells, we investigated also the presence of some transcripts involved in GI permeability [occludin (OCLN), protease-activated receptor-2 (PAR-2)] and in the inflammatory mechanism [interleukin (IL)-8, IL-6, IL-1b, tumor necrosis factor alpha (TNFα), calprotectin (CALP), heme oxygenase-1 (HO-1)]. Finally, the metabolome and the microbiota profiles were analyzed. No variation in FCM and IgA content and no differences in OCLN and CALP gene expression between rest and training were observed. On the contrary, an increase in PAR-2 and HO-1 transcripts, a reduction in total antioxidant activity, and a different profile of microbiota and metabolomics data were observed. Collectively, the data in the present study indicated that physical exercise in our model could be considered a mild stressor stimulus.

RevDate: 2020-05-06

Coenen AR, Hu SK, Luo E, et al (2020)

A Primer for Microbiome Time-Series Analysis.

Frontiers in genetics, 11:310.

Time-series can provide critical insights into the structure and function of microbial communities. The analysis of temporal data warrants statistical considerations, distinct from comparative microbiome studies, to address ecological questions. This primer identifies unique challenges and approaches for analyzing microbiome time-series. In doing so, we focus on (1) identifying compositionally similar samples, (2) inferring putative interactions among populations, and (3) detecting periodic signals. We connect theory, code and data via a series of hands-on modules with a motivating biological question centered on marine microbial ecology. The topics of the modules include characterizing shifts in community structure and activity, identifying expression levels with a diel periodic signal, and identifying putative interactions within a complex community. Modules are presented as self-contained, open-access, interactive tutorials in R and Matlab. Throughout, we highlight statistical considerations for dealing with autocorrelated and compositional data, with an eye to improving the robustness of inferences from microbiome time-series. In doing so, we hope that this primer helps to broaden the use of time-series analytic methods within the microbial ecology research community.

RevDate: 2020-05-06

Bezuidt OKI, Lebre PH, Pierneef R, et al (2020)

Phages Actively Challenge Niche Communities in Antarctic Soils.

mSystems, 5(3): pii:5/3/e00234-20.

By modulating the structure, diversity, and trophic outputs of microbial communities, phages play crucial roles in many biomes. In oligotrophic polar deserts, the effects of katabatic winds, constrained nutrients, and low water availability are known to limit microbial activity. Although phages may substantially govern trophic interactions in cold deserts, relatively little is known regarding the precise ecological mechanisms. Here, we provide the first evidence of widespread antiphage innate immunity in Antarctic environments using metagenomic sequence data from hypolith communities as model systems. In particular, immunity systems such as DISARM and BREX are shown to be dominant systems in these communities. Additionally, we show a direct correlation between the CRISPR-Cas adaptive immunity and the metavirome of hypolith communities, suggesting the existence of dynamic host-phage interactions. In addition to providing the first exploration of immune systems in cold deserts, our results suggest that phages actively challenge niche communities in Antarctic polar deserts. We provide evidence suggesting that the regulatory role played by phages in this system is an important determinant of bacterial host interactions in this environment.IMPORTANCE In Antarctic environments, the combination of both abiotic and biotic stressors results in simple trophic levels dominated by microbiomes. Although the past two decades have revealed substantial insights regarding the diversity and structure of microbiomes, we lack mechanistic insights regarding community interactions and how phages may affect these. By providing the first evidence of widespread antiphage innate immunity, we shed light on phage-host dynamics in Antarctic niche communities. Our analyses reveal several antiphage defense systems, including DISARM and BREX, which appear to dominate in cold desert niche communities. In contrast, our analyses revealed that genes which encode antiphage adaptive immunity were underrepresented in these communities, suggesting lower infection frequencies in cold edaphic environments. We propose that by actively challenging niche communities, phages play crucial roles in the diversification of Antarctic communities.

RevDate: 2020-05-05

Muñoz-Leal S, Ramirez DG, Luz HR, et al (2020)

"Candidatus Borrelia ibitipoquensis," a Borrelia valaisiana-Related Genospecies Characterized from Ixodes paranaensis in Brazil.

Microbial ecology pii:10.1007/s00248-020-01512-x [Epub ahead of print].

Borrelia burgdorferi sensu lato (Bbsl) spirochetes include the agents of Lyme borreliosis in temperate regions of the Northern Hemisphere, and merge their transmission cycles mainly with ticks of the Ixodes ricinus complex. Twenty genospecies compose Bbsl currently, and with the exception of Borrelia chilensis, and Borrelia garinii, all have been described only for North America, Europe, North Africa, and Asia. Here, we collected specimens of Ixodes paranaensis, a tick associated with swifts in a Brazilian natural park from the state of Minas Gerais, and performed a molecular characterization of 11 borrelial genes. Based on comparisons of inter and intraspecific genetic divergences, and Bayesian phylogenetic trees inferred for 16S rRNA, flaB, p66, and concatenated clpA, clpX, pepX, pyrG, recG, nifS rlpB, and uvrA genes, we demonstrate the occurrence of a new genospecies of Bbsl. "Candidatus Borrelia ibitipoquensis" Ip37 is closely related to Borrelia sp. Am501, and Borrelia valaisiana, a spirochete transmitted by ticks of the I. ricinus complex in Eurasia that uses birds as reservoirs. In a similar ecological scenario involving ticks and avian hosts, the migratory swift Streptoprocne biscutata is the sole-documented bird associated with I. paranaensis, and, although not assessed in this study, could correspond to the vertebrate reservoir of this newly described genospecies in Brazil. Pathogenic roles of "Ca. B. ibitipoquensis" are still unknown. However, its possible vector I. paranaensis is not an anthropophilic tick, so human infections would be unlikely to occur. Our finding enhances the knowledge on Bbsl in South America, highlights the occurrence of ecologically and genetically related genospecies with vastly separated geographical distributions, and calls for the attention to explore a barely known diversity of spirochetes of this group in the region.

RevDate: 2020-05-05

Perricone V, Comi M, Giromini C, et al (2020)

Green Tea and Pomegranate Extract Administered During Critical Moments of the Production Cycle Improves Blood Antiradical Activity and Alters Cecal Microbial Ecology of Broiler Chickens.

Animals : an open access journal from MDPI, 10(5): pii:ani10050785.

Phytobiotics are usually tested in feed and throughout the production cycle. However, it could be beneficial to evaluate their effects when administered only during critical moments, such as changes in feeding phases. The aim of the trial was to investigate the effect of a commercial plant extract (PE; IQV-10-P01, InQpharm Animal Health, Kuala Lumpur, Malaysia) on growth performance, blood antiradical activity and cecal microbiome when administered in drinking water to broiler chickens during the post-hatching phase and at each change of diet. In the experiment, 480 1-day-old male broiler chicks were assigned to two groups in a 50-day trial. Broilers received drinking water (C) or drinking water plus PE (T) at a rate of 2 mL/L on days 0 to 4, 10-11 and 20-21. PE did not affect performance and water intake, while total antiradical activity was improved (p < 0.05). A greater abundance of lactic acid bacteria (false discovery rate (FDR) < 0.05) was found in the T group and the result was confirmed at a lower taxonomic level with higher Lactobacillaceae abundance (FDR < 0.05). Our findings suggest that PE administration during critical moments of the production cycle of broiler chickens may exert beneficial effects at a systemic level and on gut microbial ecology.

RevDate: 2020-05-04

Ramoneda J, Le Roux JJ, Frossard E, et al (2020)

Experimental assembly reveals ecological drift as a major driver of root nodule bacterial diversity in a woody legume crop.

FEMS microbiology ecology pii:5828728 [Epub ahead of print].

Understanding how plant-associated microbial communities assemble and the role they play in plant performance are major goals in microbial ecology. For nitrogen-fixing rhizobia, community assembly is generally driven by host plant selection and soil conditions. Here, we aimed to determine the relative importance of neutral and deterministic processes in the assembly of bacterial communities of root nodules of a legume shrub adapted to extreme nutrient limitation, rooibos (Aspalathus linearis Burm. Dahlgren). We grew rooibos seedlings in soil from cultivated land and wild habitats, and mixtures of these soils, sampled from a wide geographic area, and with a fertilization treatment. Bacterial communities were characterized using next generation sequencing of part of the nodA gene (i.e. common to the core rhizobial symbionts of rooibos), and part of the gyrB gene (i.e. common to all bacterial taxa). Ecological drift alone was a major driver of taxonomic turnover in the bacterial communities of root nodules (62.6% of gyrB communities). In contrast, the assembly of core rhizobial communities (genus Mesorhizobium) was driven by dispersal limitation in concert with drift (81.1% of nodA communities). This agrees with a scenario of rooibos-Mesorhizobium specificity in spatially separated subpopulations, and low host filtering of other bacteria colonizing root nodules in a stochastic manner.

RevDate: 2020-05-03

Liu W, Wu Y, Zhang S, et al (2020)

Successful granulation and microbial differentiation of activated sludge in anaerobic/anoxic/aerobic (A2O) reactor with two-zone sedimentation tank treating municipal sewage.

Water research, 178:115825 pii:S0043-1354(20)30362-6 [Epub ahead of print].

A continuous pilot-scale A2O reactor with a two-zone sedimentation tank (A2O-TST) was constructed for the formation of aerobic granular sludge (AGS) to treat real municipal sewage. The characteristics of sludge, nutrient removal performance and the corresponding microbial ecology dynamics were studied during granulation process. Experimental results indicated that AGS with a mean particle size of 210 μm and sludge volume index after 30 min of 47.5 mL/g was successfully formed with effluent COD, total nitrogen and total phosphorus concentrations in the reactor reaching 22.8, 3.5 and 0.2 mg/L, respectively. Furthermore, high throughput data indicated that granules in settling tank-1 (ST-1) harbored slow-growing autotrophic organisms like Nitrosomonas and Nitrospira, while the flocs in settling tank-2 (ST-2) were dominated by fast-growing heterotrophic organisms including Ca. Accumulibacter, Dechloromonas, Flavobacterium, Arcobacter and Halomonas. Simulation results using computational fluid dynamics and discrete element method (CFD-DEM) modeling verified that the selection pressure created by the TST separator contributed to the retention of heavy granules (>1.011 kg/m3 density) in ST-1 zone and the withdrawal of light flocs (<1.011 kg/m3 density) from ST-2 zone. Therefore, the segregation of biomass using the TST system provides an opportunity to select for desired microbial populations and to optimize the nitrogen and phosphorus removal performance of the A2O-TST reactor. This study could add a guiding sight into the application of two-sludge system based on AGS technology for upgrading traditional A2O process.

RevDate: 2020-05-03

Wang J, Zhang X, H Yao (2020)

Optimizing ultracentrifugation conditions for DNA-based stable isotope probing (DNA-SIP).

Journal of microbiological methods pii:S0167-7012(19)31101-7 [Epub ahead of print].

DNA-SIP (DNA-based stable isotope probing) is increasingly being employed in soil microbial ecology to identify those microbes assimilating the 13C/15N labelled substrate. Isopycnic gradient centrifugation is the primary experimental process for conducting DNA-SIP. However, diverse centrifugal conditions have been used in various recent studies. In order to get the optimum conditions of centrifugation for DNA-SIP, centrifugation time (36, 42, 48, 60 h), speed (45,000, 55,000 rpm) and the initial buoyant density (1.69, 1.71, 1.725 g ml-1), as were used extensively in related studies, were tested in this experiment with the Vti 65.2 rotor. DNA with either 13C-labelling or unlabelled was extracted from a paddy soil pre-incubated with either 13C-labelled or natural abundance glucose. After ultracentrifugation, the gene abundance of bacterial 16S rRNA, fungal 18S rRNA, bacterial and archaeal amoA within the fractioned DNA was detected. The results showed that centrifugation for 48 h was enough for the DNA to reach stabilization in the CsCl solution. The initial density of the mixed solution was best adjusted to 1.71 g ml-1 to ensure that most of the genes were concentrated on the middle fractions of the density gradient. Increasing the centrifugation speed would increase the density gradient of fractions; therefore, 45,000 rpm (184,000 g) was recommended so as to obtain the more widespread pattern of DNA in the centrifugal tube. We hope these findings will assist future researchers to conduct optimum ultracentrifugation for DNA-SIP.

RevDate: 2020-05-04

Castro MO, Hartman T, Coutinho T, et al (2020)

Current Understanding of the History, Global Spread, Ecology, Evolution, and Management of the Corn Bacterial Leaf Streak Pathogen, Xanthomonas vasicola pv. vasculorum.

Phytopathology [Epub ahead of print].

Bacterial leaf streak of corn, caused by Xanthomonas vasicola pv. vasculorum, has been present in South Africa for over 70 years, but is an emerging disease of corn in North and South America. The only scientific information pertaining to this disease on corn came from work done in South Africa, which primarily investigated host range on other African crops, such as sugarcane and banana. As a result, when the disease was first reported in the United States in 2016, there was very limited information on where this pathogen came from, how it infects its host, what plant tissue(s) it is capable of infecting, where initial inoculum comes from at the beginning of each crop season, how the bacterium spreads from plant to plant and long distance, what meteorological variables and agronomic practices favor disease development and spread, how many other plant species X. vasicola pv. vasculorum is capable of infecting or using as alternate hosts, and if the bacterium will be able to persist in all corn growing regions of the United States. There were also no rapid diagnostic assays available which initially hindered prompt identification prior to the development of molecular diagnostic tools. The goal of this synthesis is to review the history of X. vasicola pv. vasculorum and bacterial leaf streak in South Africa and its movement to North and South America, and highlight the recent research that has been done in response to the emergence of this bacterial disease.

RevDate: 2020-05-02

Li YJ, Chen X, Kwan TK, et al (2020)

Dietary Fiber Protects against Diabetic Nephropathy through Short-Chain Fatty Acid-Mediated Activation of G Protein-Coupled Receptors GPR43 and GPR109A.

Journal of the American Society of Nephrology : JASN pii:ASN.2019101029 [Epub ahead of print].

BACKGROUND: Studies have reported "dysbiotic" changes to gut microbiota, such as depletion of gut bacteria that produce short-chain fatty acids (SCFAs) through gut fermentation of fiber, in CKD and diabetes. Dietary fiber is associated with decreased inflammation and mortality in CKD, and SCFAs have been proposed to mediate this effect.

METHODS: To explore dietary fiber's effect on development of experimental diabetic nephropathy, we used streptozotocin to induce diabetes in wild-type C57BL/6 and knockout mice lacking the genes encoding G protein-coupled receptors GPR43 or GPR109A. Diabetic mice were randomized to high-fiber, normal chow, or zero-fiber diets, or SCFAs in drinking water. We used proton nuclear magnetic resonance spectroscopy for metabolic profiling and 16S ribosomal RNA sequencing to assess the gut microbiome.

RESULTS: Diabetic mice fed a high-fiber diet were significantly less likely to develop diabetic nephropathy, exhibiting less albuminuria, glomerular hypertrophy, podocyte injury, and interstitial fibrosis compared with diabetic controls fed normal chow or a zero-fiber diet. Fiber beneficially reshaped gut microbial ecology and improved dysbiosis, promoting expansion of SCFA-producing bacteria of the genera Prevotella and Bifidobacterium, which increased fecal and systemic SCFA concentrations. Fiber reduced expression of genes encoding inflammatory cytokines, chemokines, and fibrosis-promoting proteins in diabetic kidneys. SCFA-treated diabetic mice were protected from nephropathy, but not in the absence of GPR43 or GPR109A. In vitro, SCFAs modulated inflammation in renal tubular cells and podocytes under hyperglycemic conditions.

CONCLUSIONS: Dietary fiber protects against diabetic nephropathy through modulation of the gut microbiota, enrichment of SCFA-producing bacteria, and increased SCFA production. GPR43 and GPR109A are critical to SCFA-mediated protection against this condition. Interventions targeting the gut microbiota warrant further investigation as a novel renoprotective therapy in diabetic nephropathy.

RevDate: 2020-05-01

Wang W, Li Z, Zeng L, et al (2020)

The oxidation of hydrocarbons by diverse heterotrophic and mixotrophic bacteria that inhabit deep-sea hydrothermal ecosystems.

The ISME journal pii:10.1038/s41396-020-0662-y [Epub ahead of print].

Hydrothermal activity can generate numerous and diverse hydrocarbon compounds. However, little is known about the influence of such hydrocarbons on deep-sea hydrothermal microbial ecology. We hypothesize that certain bacteria live on these hydrocarbons. Therefore, in this study, the distribution of hydrocarbons and their associated hydrocarbon-degrading bacteria were investigated at deep-sea hydrothermal vents at the Southern Mid-Atlantic Ridge, the Southwest Indian Ridge, and the East Pacific Rise. A variety of hydrocarbon-degrading consortia were obtained from hydrothermal samples collected at the aforementioned sites after low-temperature enrichment under high hydrostatic pressures, and the bacteria responsible for the degradation of hydrocarbons were investigated by DNA-based stable-isotope probing with uniformly 13C-labeled hydrocarbons. Unusually, we identified several previously recognized sulfur-oxidizing chemoautotrophs as hydrocarbon-degrading bacteria, e.g., the SAR324 group, the SUP05 clade, and Sulfurimonas, and for the first time confirmed their ability to degrade hydrocarbons. In addition, Erythrobacter, Pusillimonas, and SAR202 clade were shown to degrade polycyclic aromatic hydrocarbons for the first time. These results together with relatively high abundance in situ of most of the above-described bacteria highlight the potential influence of hydrocarbons in configuring the vent microbial community, and have made the importance of mixotrophs in hydrothermal vent ecosystems evident.

RevDate: 2020-04-30

Johnston-Monje D, J Lopez Mejia (2020)

Botanical microbiomes on the cheap: Inexpensive molecular fingerprinting methods to study plant-associated communities of bacteria and fungi.

Applications in plant sciences, 8(4):e11334 pii:APS311334.

High-throughput sequencing technologies have revolutionized the study of plant-associated microbial populations, but they are relatively expensive. Molecular fingerprinting techniques are more affordable, yet yield considerably less information about the microbial community. Does this mean they are no longer useful for plant microbiome research? In this paper, we review the past 10 years of studies on plant-associated microbiomes using molecular fingerprinting methodologies, including single-strand conformation polymorphism (SSCP), denaturing gradient gel electrophoresis (DGGE), amplicon length heterogeneity PCR (LH-PCR), ribosomal intergenic spacer analysis (RISA) and automated ribosomal intergenic spacer analysis (ARISA), and terminal restriction fragment length polymorphism (TRFLP). We also present data juxtaposing results from TRFLP methods with those generated using Illumina sequencing in the comparison of rhizobacterial populations of Brazilian maize and fungal surveys in Canadian tomato roots. In both cases, the TRFLP approach yielded the desired results at a level of resolution comparable to that of the MiSeq method, but at a fraction of the cost. Community fingerprinting methods (especially TRFLP) remain relevant for the identification of dominant microbes in a population, the observation of shifts in plant microbiome community diversity, and for screening samples before their use in more sensitive and expensive approaches.

RevDate: 2020-04-30

Kopprio GA, Neogi SB, Rashid H, et al (2020)

Vibrio and Bacterial Communities Across a Pollution Gradient in the Bay of Bengal: Unraveling Their Biogeochemical Drivers.

Frontiers in microbiology, 11:594.

The highly populated coasts of the Bay of Bengal are particularly vulnerable to water-borne diseases, pollution and climatic extremes. The environmental factors behind bacterial community composition and Vibrio distribution were investigated in an estuarine system of a cholera-endemic region in the coastline of Bangladesh. Higher temperatures and sewage pollution were important drivers of the abundance of toxigenic Vibrio cholerae. A closer relation between non-culturable Vibrio and particulate organic matter (POM) was inferred during the post-monsoon. The distribution of operational taxonomic units (OTUs) of Vibrio genus was likely driven by salinity and temperature. The resuspension of sediments increased Vibrio abundance and organic nutrient concentrations. The δ13C dynamic in POM followed an increasing gradient from freshwater to marine stations; nevertheless, it was not a marker of sewage pollution. Bacteroidales and culturable coliforms were reliable indicators of untreated wastewater during pre and post-monsoon seasons. The presumptive incorporation of depleted-ammonium derived from ammonification processes under the hypoxic conditions, by some microorganisms such as Cloacibacterium and particularly by Arcobacter nearby the sewage discharge, contributed to the drastic 15N depletion in the POM. The likely capacity of extracellular polymeric substances production of these taxa may facilitate the colonization of POM from anthropogenic origin and may signify important properties for wastewater bioremediation. Genera of potential pathogens other than Vibrio associated with sewage pollution were Acinetobacter, Aeromonas, Arcobacter, and Bergeyella. The changing environmental conditions of the estuary favored the abundance of early colonizers and the island biogeography theory explained the distribution of some bacterial groups. This multidisciplinary study evidenced clearly the eutrophic conditions of the Karnaphuli estuary and assessed comprehensively its current bacterial baseline and potential risks. The prevailing conditions together with human overpopulation and frequent natural disasters, transform the region in one of the most vulnerable to climate change. Adaptive management strategies are urgently needed to enhance ecosystem health.

RevDate: 2020-04-30

Lang M, Baumgartner M, Rożalska A, et al (2020)

Crypt residing bacteria and proximal colonic carcinogenesis in a mouse model of Lynch syndrome.

International journal of cancer [Epub ahead of print].

Colorectal cancer is a multifactorial disease involving inherited DNA mutations, environmental factors, gut inflammation, and intestinal microbiota. Certain germline mutations within the DNA mismatch repair system are associated with Lynch syndrome tumors including right-sided colorectal cancer with mucinous phenotype and presence of an inflammatory infiltrate. Such tumors are more often associated with bacterial biofilms, which may contribute to disease onset and progression. Inflammatory bowel diseases are also associated with colorectal cancer and intestinal dysbiosis. Herein we addressed the question, whether inflammation can aggravate colorectal cancer development under mismatch repair deficiency. MSH2loxP/loxP Vill-cre mice were crossed into the IL-10-/- background to study the importance of inflammation and mucosal bacteria as a driver of tumorigenesis in a Lynch syndrome mouse model. An increase in large bowel tumorigenesis was found in double knockout mice both under conventional housing and under specific pathogen-free conditions. This increase was mostly due to the development of proximal tumors, a hotspot for tumorigenesis in Lynch syndrome, and was associated with a higher degree of inflammation. Additionally, bacterial invasion into the mucus of tumor crypts was observed in the proximal tumors. Inflammation shifted fecal and mucosal microbiota composition and was associated with enrichment in Escherichia-Shigella as well as Akkermansia, Bacteroides, and Parabacteroides genera in fecal samples. Tumor-bearing double knockout mice showed a similar enrichment for Escherichia-Shigella and Parabacteroides. Lactobacilli, Lachnospiraceae and Muribaculaceae family members were depleted upon inflammation. In summary, chronic inflammation aggravates colonic tumorigenesis under mismatch repair deficiency and is associated with a shift in microbiota composition. This article is protected by copyright. All rights reserved.

RevDate: 2020-04-29

Duar RM, Henrick BM, Casaburi G, et al (2020)

Integrating the Ecosystem Services Framework to Define Dysbiosis of the Breastfed Infant Gut: The Role of B. infantis and Human Milk Oligosaccharides.

Frontiers in nutrition, 7:33.

Mounting evidence supports a connection between the composition of the infant gut microbiome and long-term health. In fact, aberrant microbiome compositions during key developmental windows in early life are associated with increased disease risk; therefore, making pertinent modifications to the microbiome during infancy offers significant promise to improve human health. There is growing support for integrating the concept of ecosystem services (the provision of benefits from ecosystems to humans) in linking specific microbiome functions to human well-being. This framework is widely applied in conservation efforts of macro-ecosystems and offers a systematic approach to guide restoration actions aimed to recover critical ecological functions. The aim of this work is to apply the ecosystem services framework to integrate recent studies demonstrating stable alteration of the gut microbiome of breastfed infants when Bifidobacterium longum subsp. infantis EVC001, a gut symbiont capable of efficiently utilizing human milk oligosaccharides into organic acids that are beneficial for the infant and lower intestinal pH, is reintroduced. Additionally, using examples from the literature we illustrate how the absence of B. infantis results in diminished ecosystem services, which may be associated with health consequences related to immune and metabolic disorders. Finally, we propose a model by which infant gut dysbiosis can be defined as a reduction in ecosystem services supplied to the host by the gut microbiome rather than merely changes in diversity or taxonomic composition. Given the increased interest in targeted microbiome modification therapies to decrease acute and chronic disease risk, the model presented here provides a framework to assess the effectiveness of such strategies from a host-centered perspective.

RevDate: 2020-04-28

López-García P, D Moreira (2020)

The Syntrophy hypothesis for the origin of eukaryotes revisited.

Nature microbiology, 5(5):655-667.

The discovery of Asgard archaea, phylogenetically closer to eukaryotes than other archaea, together with improved knowledge of microbial ecology, impose new constraints on emerging models for the origin of the eukaryotic cell (eukaryogenesis). Long-held views are metamorphosing in favour of symbiogenetic models based on metabolic interactions between archaea and bacteria. These include the classical Searcy's and Hydrogen hypothesis, and the more recent Reverse Flow and Entangle-Engulf-Endogenize models. Two decades ago, we put forward the Syntrophy hypothesis for the origin of eukaryotes based on a tripartite metabolic symbiosis involving a methanogenic archaeon (future nucleus), a fermentative myxobacterial-like deltaproteobacterium (future eukaryotic cytoplasm) and a metabolically versatile methanotrophic alphaproteobacterium (future mitochondrion). A refined version later proposed the evolution of the endomembrane and nuclear membrane system by invagination of the deltaproteobacterial membrane. Here, we adapt the Syntrophy hypothesis to contemporary knowledge, shifting from the original hydrogen and methane-transfer-based symbiosis (HM Syntrophy) to a tripartite hydrogen and sulfur-transfer-based model (HS Syntrophy). We propose a sensible ecological scenario for eukaryogenesis in which eukaryotes originated in early Proterozoic microbial mats from the endosymbiosis of a hydrogen-producing Asgard archaeon within a complex sulfate-reducing deltaproteobacterium. Mitochondria evolved from versatile, facultatively aerobic, sulfide-oxidizing and, potentially, anoxygenic photosynthesizing alphaproteobacterial endosymbionts that recycled sulfur in the consortium. The HS Syntrophy hypothesis accounts for (endo)membrane, nucleus and metabolic evolution in a realistic ecological context. We compare and contrast the HS Syntrophy hypothesis to other models of eukaryogenesis, notably in terms of the mode and tempo of eukaryotic trait evolution, and discuss several model predictions and how these can be tested.

RevDate: 2020-04-27

Pishchany G (2020)

Applying microbial ecology to antimicrobial discovery.

Current opinion in microbiology, 57:7-12 pii:S1369-5274(20)30039-4 [Epub ahead of print].

Introduction of antibiotics into clinical use has contributed to some of the greatest improvements to public health in the 20th century. Most antibiotics are based on antimicrobials that were isolated from environmental microorganisms over 50 years ago, but emerging resistance requires discovery of new molecules and development of these molecules into therapeutics. Bioinformatic analyses of microbial genomes indicate that many more microbial bioactive molecules remain undiscovered. Understanding when, where, and why these molecules are produced informs efforts to tap into the hidden unexplored chemical diversity. Expanding the search to undersampled ecological niches and improving culturing techniques will ensure discovery of new antibiotics.

RevDate: 2020-04-26

Sun H, Zhang Y, Tan S, et al (2020)

DMSP-Producing Bacteria Are More Abundant in the Surface Microlayer than Subsurface Seawater of the East China Sea.

Microbial ecology pii:10.1007/s00248-020-01507-8 [Epub ahead of print].

Microbial production and catabolism of dimethylsulfoniopropionate (DMSP), generating the climatically active gases dimethyl sulfide (DMS) and methanethiol (MeSH), have key roles in global carbon and sulfur cycling, chemotaxis, and atmospheric chemistry. Microorganisms in the sea surface microlayer (SML), the interface between seawater and atmosphere, likely play an important role in the generation of DMS and MeSH and their exchange to the atmosphere, but little is known about these SML microorganisms. Here, we investigated the differences between bacterial community structure and the distribution and transcription profiles of the key bacterial DMSP synthesis (dsyB and mmtN) and catabolic (dmdA and dddP) genes in East China Sea SML and subsurface seawater (SSW) samples. Per equivalent volume, bacteria were far more abundant (~ 7.5-fold) in SML than SSW, as were those genera predicted to produce DMSP. Indeed, dsyB (~ 7-fold) and mmtN (~ 4-fold), robust reporters for bacterial DMSP production, were also far more abundant in SML than SSW. In addition, the SML had higher dsyB transcripts (~ 3-fold) than SSW samples, which may contribute to the significantly higher DMSP level observed in SML compared with SSW. Furthermore, the abundance of bacteria with dmdA and their transcription were higher in SML than SSW samples. Bacteria with dddP and transcripts were also prominent, but less than dmdA and presented at similar levels in both layers. These data indicate that the SML might be an important hotspot for bacterial DMSP production as well as generating the climatically active gases DMS and MeSH, a portion of which are likely transferred to the atmosphere.

RevDate: 2020-04-25

Gorski G, Dailey H, Fisher AT, et al (2020)

Denitrification during infiltration for managed aquifer recharge: Infiltration rate controls and microbial response.

The Science of the total environment, 727:138642 pii:S0048-9697(20)32158-6 [Epub ahead of print].

Managed aquifer recharge (MAR) systems can be designed and operated to improve water supply and quality simultaneously by creating favorable conditions for contaminant removal during infiltration through shallow soils. We present results from laboratory flow-through column experiments, using intact soil cores from two MAR sites, elucidating conditions that are favorable to nitrate (NO3) removal via microbial denitrification during infiltration. Experiments focused on quantitative relations between infiltration rate and the presence or absence of a carbon-rich permeable reactive barrier (PRB) on both amounts and rates of nitrate removal during infiltration and associated shifts in microbial ecology. Experiments were conducted using a range of infiltration rates relevant to MAR (0.3-1.4 m/day), with PRBs made of native soil (NS), woodchips (WC) and a 50:50 mixture of woodchips and native soil (MIX). The latter two (carbon-rich) PRB treatments led to statistically significant increases in the amount of nitrate removed by increasing zero-order denitrification rates, both within the PRB materials and in the underlying soil. The highest fraction of nitrate removal occurred at the lowest infiltration rates for all treatments. However, the highest nitrogen mass removal (∆NL) was observed at 0.4-0.7 m/day for both the WC and MIX treatments. In contrast, the maximum ∆NL for the NS treatment was observed at the lowest infiltration rates measured (~0.3 m/day). Further, both carbon-rich PRBs had a substantial impact on the soil microbial ecology in the underlying soil, with lower overall diversity and a greater relative abundance of groups known to degrade carbon and metabolize nitrogen. These results demonstrate that infiltration rates and carbon availability can combine to create favorable conditions for denitrification during infiltration for MAR and show how these factors shape and sustain the microbial community structures responsible for nutrient cycling in associated soils.

RevDate: 2020-04-25

Moran MC, Beck LA, CT Richardson (2020)

A Spectrum of Skin Disease: How Staphylococcus aureus Colonization, Barrier Dysfunction, and Cytokines Shape the Skin.

The Journal of investigative dermatology, 140(5):941-944.

Cytokines are key mediators of skin homeostasis and disease through their effects on keratinocytes, skin barrier integrity, immune activation, and microbial ecology. Sirobhushanam et al. (2020) suggest that the IFN signature in lupus erythematosus (LE) alters expression of epithelial barrier and adhesin genes, which, in turn, promotes Staphylococcus aureus colonization. This work highlights the need to better understand both barrier function and S. aureus colonization in LE, two new potential therapeutic targets for the treatment of LE.

RevDate: 2020-04-24

Hanya G, Tackmann J, Sawada A, et al (2020)

Fermentation Ability of Gut Microbiota of Wild Japanese Macaques in the Highland and Lowland Yakushima: In Vitro Fermentation Assay and Genetic Analyses.

Microbial ecology pii:10.1007/s00248-020-01515-8 [Epub ahead of print].

Wild Japanese macaques (Macaca fuscata Blyth) living in the highland and lowland areas of Yakushima are known to have different diets, with highland individuals consuming more leaves. We aim to clarify whether and how these differences in diet are also reflected by gut microbial composition and fermentation ability. Therefore, we conduct an in vitro fermentation assay using fresh feces from macaques as inoculum and dry leaf powder of Eurya japonica Thunb. as a substrate. Fermentation activity was higher for feces collected in the highland, as evidenced by higher gas and butyric acid production and lower pH. Genetic analysis indicated separation of highland and lowland in terms of both community structure and function of the gut microbiota. Comparison of feces and suspension after fermentation indicated that the community structure changed during fermentation, and the change was larger for lowland samples. Analysis of the 16S rRNA V3-V4 barcoding region of the gut microbiota showed that community structure was clearly clustered between the two areas. Furthermore, metagenomic analysis indicated separation by gene and pathway abundance patterns. Two pathways (glycogen biosynthesis I and D-galacturonate degradation I) were enriched in lowland samples, possibly related to the fruit-eating lifestyle in the lowland. Overall, we demonstrated that the more leaf-eating highland Japanese macaques harbor gut microbiota with higher leaf fermentation ability compared with the more fruit-eating lowland ones. Broad, non-specific taxonomic and functional gut microbiome differences suggest that this pattern may be driven by a complex interplay between many taxa and pathways rather than single functional traits.


ESP Quick Facts

ESP Origins

In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

ESP Content

When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

ESP Help

Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

ESP Plans

With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

Electronic Scholarly Publishing
961 Red Tail Lane
Bellingham, WA 98226

E-mail: RJR8222 @

Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin (and even a collection of poetry — Chicago Poems by Carl Sandburg).


ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.


Biographical information about many key scientists.

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are now being automatically maintained and generated on the ESP site.

ESP Picks from Around the Web (updated 07 JUL 2018 )