Viewport Size Code:
Login | Create New Account
picture

  MENU

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

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

icon

Bibliography Options Menu

icon
QUERY RUN:
HITS:
PAGE OPTIONS:
Hide Abstracts   |   Hide Additional Links
NOTE:
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.

More About:  ESP | OUR CONTENT | THIS WEBSITE | WHAT'S NEW | WHAT'S HOT

ESP: PubMed Auto Bibliography 05 Jun 2020 at 01:44 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: 2020-06-04

Van den Abbeele P, Duysburgh C, Rakebrandt M, et al (2020)

Dried Yeast Cell Walls High in Beta-Glucan and Mannan-Oligosaccharides Positively Affect Microbial Composition and Activity in the Canine Gastrointestinal Tract in Vitro.

Journal of animal science pii:5851475 [Epub ahead of print].

The outer cell wall of yeast is characterized by high levels of β-glucans and mannan-oligosaccharides (MOS), which have been linked with beneficial effects on intestinal health and immune status in dogs. In this study, a standardized in vitro simulation of the canine gastrointestinal tract (Simulator of the Canine Intestinal Microbial Ecosystem; SCIME™) was used to evaluate the effect of a Saccharomyces cerevisiae-based product, consisting of 27.5% β-glucans and 22.5% MOS, on the activity (as assessed by measurement of fermentative metabolites) and composition (as assessed by 16S-targeted Illumina sequencing) of canine intestinal microbiota. The Saccharomyces cerevisiae-based product was tested at 3 different dosages, i.e. 0.5 g/day, 1.0 g/day and 2.0 g/day. A dose-dependent fermentation pattern was observed along the entire length of the colon, as shown by the increased production of the health-related acetate, propionate and butyrate for the three concentrations tested (0.5, 1.0 and 2.0 g/day). A consistent finding for all three tested concentrations was the increased propionate production (p<0.05) in the simulated proximal and distal colon. These changes in terms of fermentative metabolites could be linked to specific microbial alterations at family level, such as the specific stimulation of the propionate-producing families Porphyromonadaceae and Prevotellaceae upon in vitro exposure to the Saccharomyces cerevisiae-based product. Other consistent changes in community composition upon repeated exposure included the decrease in the Enterobacteriaceae and the Fusobacteriaceae families, which both contain several potentially opportunistic pathogens. Altogether, the generated data support a possible health-promoting role of a product high in β-glucans and MOS when supplemented to the dogs' diet.

RevDate: 2020-06-04

Xiong J, Li X, Yan M, et al (2020)

Comparable Ecological Processes Govern the Temporal Succession of Gut Bacteria and Microeukaryotes as Shrimp Aged.

Microbial ecology pii:10.1007/s00248-020-01533-6 [Epub ahead of print].

Understanding the rules that govern the successions of gut microbiota is prerequisite for testing general ecological theories and sustaining a desirable microbiota. However, the ignorance of microeukaryotes raises the question of whether gut microeukaryotes are assembled according to the same rules as bacteria. We tracked the shrimp gut bacterial and microeukaryotic communities by a longitudinal dense sampling. The successions of both domains were significantly correlated with host age, with relatively stable microeukaryotic communities in adult shrimp. Gut microeukaryotes exhibited significantly higher turnover rate, but fewer transient species, lower proportion of temporal generalists, and narrower habitat niche breadth than bacteria. The γ-diversity partitioning analysis revealed that the successions of gut microbiotas were primarily ascribed to the high dissimilarity as shrimp aged ([Formula: see text]IntraTimes), whereas the relative importance of [Formula: see text]IntraTimes was significantly higher for microeukaryotes than that for bacteria. Compared with contrasting ecological processes in governing free-living bacteria and microeukaryotes, the ecological patterns were comparable between host-associated gut counterparts. However, the gut microeukaryotes were governed more strongly by deterministic selection relative to nestedness compared with the gut bacteria, which supports the "size-plasticity" hypothesis. Our results highlight the importance of independently interpreting free-living and host-associated meta-communities for a comprehensive understanding of the processes that govern microbial successions.

RevDate: 2020-06-04

Monteiro DA, Fonseca EDS, Rodrigues RAR, et al (2020)

Structural and functional shifts of soil prokaryotic community due to Eucalyptus plantation and rotation phase.

Scientific reports, 10(1):9075 pii:10.1038/s41598-020-66004-x.

Agriculture, forestry and other land uses are currently the second highest source of anthropogenic greenhouse gases (GHGs) emissions. In soil, these gases derive from microbial activity, during carbon (C) and nitrogen (N) cycling. To investigate how Eucalyptus land use and growth period impact the microbial community, GHG fluxes and inorganic N levels, and if there is a link among these variables, we monitored three adjacent areas for 9 months: a recently planted Eucalyptus area, fully developed Eucalyptus forest (final of rotation) and native forest. We assessed the microbial community using 16S rRNA gene sequencing and qPCR of key genes involved in C and N cycles. No considerable differences in GHG flux were evident among the areas, but logging considerably increased inorganic N levels. Eucalyptus areas displayed richer and more diverse communities, with selection for specific groups. Land use influenced communities more extensively than the time of sampling or growth phase, although all were significant modulators. Several microbial groups and genes shifted temporally, and inorganic N levels shaped several of these changes. No correlations among microbial groups or genes and GHG were found, suggesting no link among these variables in this short-rotation Eucalyptus study.

RevDate: 2020-06-03

Semiatizki A, Weiss B, Bagim S, et al (2020)

Effects, interactions, and localization of Rickettsia and Wolbachia in the house fly parasitoid, Spalangia endius.

Microbial ecology pii:10.1007/s00248-020-01520-x [Epub ahead of print].

Many insect species harbor facultative microbial symbionts that affect their biology in diverse ways. Here, we studied the effects, interactions, and localization of two bacterial symbionts-Wolbachia and Rickettsia-in the parasitoid Spalangia endius. We crossed between four S. endius colonies-Wolbachia only (W), Rickettsia only (R), both (WR), and none (aposymbiotic, APS) (16 possible crosses) and found that Wolbachia induces incomplete cytoplasmic incompatibility (CI), both when the males are W or WR. Rickettsia did not cause reproductive manipulations and did not rescue the Wolbachia-induced CI. However, when R females were crossed with W or WR males, significantly less offspring were produced compared with that of control crosses. In non-CI crosses, the presence of Wolbachia in males caused a significant reduction in offspring numbers. Females' developmental time was significantly prolonged in the R colony, with adults starting to emerge one day later than the other colonies. Other fitness parameters did not differ significantly between the colonies. Using fluorescence in situ hybridization microscopy in females, we found that Wolbachia is localized alongside Rickettsia inside oocytes, follicle cells, and nurse cells in the ovaries. However, Rickettsia is distributed also in muscle cells all over the body, in ganglia, and even in the brain.

RevDate: 2020-06-03

Hejduková E, Elster J, L Nedbalová (2020)

Annual Cycle of Freshwater Diatoms in the High Arctic Revealed by Multiparameter Fluorescent Staining.

Microbial ecology pii:10.1007/s00248-020-01521-w [Epub ahead of print].

Diatoms (Bacillariophyceae) are important primary producers in a wide range of hydro-terrestrial habitats in polar regions that are characterized by many extreme environmental conditions. Nevertheless, how they survive periods of drought and/or freeze remains unknown. A general strategy of microorganisms to overcome adverse conditions is dormancy, but morphologically distinct diatom resting stages are rare. This study aimed to evaluate the annual cycle of freshwater diatoms in the High Arctic (Central Spitsbergen) and provide an insight into their physiological cell status variability. The diversity and viability of diatom cells were studied in samples collected five times at four study sites, tracing the key events for survival (summer vegetative season, autumn dry-freezing, winter freezing, spring melting, summer vegetative season [again]). For viability evaluation, a multiparameter fluorescent staining was used in combination with light microscopy and allowed to reveal the physiological status at a single-cell level. The proportions of the cell categories were seasonally and locality dependent. The results suggested that a significant portion of vegetative cells survive winter and provide an inoculum for the following vegetative season. The ice thickness significantly influenced spring survival. The thicker the ice layer was, the more dead cells and fewer other stages were observed. The influence of the average week max-min temperature differences in autumn and winter was not proven.

RevDate: 2020-06-03

Aliyu H, Mohr T, Cowan D, et al (2020)

Time-Course Transcriptome of Parageobacillus thermoglucosidasius DSM 6285 Grown in the Presence of Carbon Monoxide and Air.

International journal of molecular sciences, 21(11): pii:ijms21113870.

Parageobacillus thermoglucosidasius is a metabolically versatile, facultatively anaerobic thermophile belonging to the family Bacillaceae. Previous studies have shown that this bacterium harbours co-localised genes coding for a carbon monoxide (CO) dehydrogenase (CODH) and Ni-Fe hydrogenase (Phc) complex and oxidises CO and produces hydrogen (H2) gas via the water-gas shift (WGS) reaction. To elucidate the genetic events culminating in the WGS reaction, P. thermoglucosidasius DSM 6285 was cultivated under an initial gas atmosphere of 50% CO and 50% air and total RNA was extracted at ~8 (aerobic phase), 20 (anaerobic phase), 27 and 44 (early and late hydrogenogenic phases) hours post inoculation. The rRNA-depleted fraction was sequenced using Illumina NextSeq, v2.5, 1x75bp chemistry. Differential expression revealed that at 8 vs 20, 20 vs 27 and 27 vs 44 hours post inoculation, 2190, 2118 and 231 transcripts were differentially (FDR < 0.05) expressed. Cluster analysis revealed 26 distinct gene expression trajectories across the four time points. Of these, two similar clusters, showing overexpression at 20 relative to 8 hours and depletion at 27 and 44 hours, harboured the CODH and Phc transcripts, suggesting possible regulation by O2. The transition between aerobic respiration and anaerobic growth was marked by initial metabolic deterioration, as reflected by up-regulation of transcripts linked to sporulation and down-regulation of transcripts linked to flagellar assembly and metabolism. However, the transcriptome and growth profiles revealed the reversal of this trend during the hydrogenogenic phase.

RevDate: 2020-06-03

Du R, Wu Q, Y Xu (2020)

Chinese Liquor Fermentation: Identification of Key Flavor-Producing Lactobacillus spp. by Quantitative Profiling with Indigenous Internal Standards.

Applied and environmental microbiology, 86(12): pii:AEM.00456-20.

Identifying the functional microbes in spontaneous food fermentation is important for improving food quality. To identify the key flavor producers in Chinese liquor fermentation, we propose a novel quantitative microbiome profiling method that uses indigenous internal standards to normalize high-throughput amplicon sequencing results. We screened Lactobacillus acetotolerans and Lactobacillus jinshani as indigenous internal standards based on their high distribution frequencies and relative abundances. After determining the absolute abundance of indigenous internal standards using quantitative PCR with species-specific primers, the liquor-fermented bacterial community and its dynamics were better characterized by internal standards normalization. Based on quantitative microbiome profiling, we identified that Lactobacillus was a key flavor producer correlated with eight flavor compounds. Metatranscriptomic analysis indicated that Lactobacillus was active in transcribing genes involving the biosynthesis of flavor compounds and their precursors. This work has developed a novel and extensible absolute quantification method for microbiota that will alleviate concerns in the statistical analyses based on relative microbiome profiling, and shed insights into the function of Lactobacillus in food fermentation. It can potentially be applied to other microbial ecology studies.IMPORTANCE In this study, we developed a novel strategy using indigenous internal standards to normalize the high-throughput amplicon sequencing results. We chose two Lactobacillus species as indigenous internal standards and characterized the absolute abundance of the bacterial community. Further, we identified Lactobacillus as the key flavor producer using quantitative microbiome profiling combined with multivariate statistics and metatranscriptomic analysis. This work developed a novel strategy for absolute quantitative abundance analysis of microbiota and expanded our understanding of the role of Lactobacillus in food fermentation.

RevDate: 2020-06-03
CmpDate: 2013-03-07

Lee HJ, Han SI, KS Whang (2012)

Catenulispora graminis sp. nov., a rhizobacterium from bamboo (Phyllostachys nigro var. henonis) rhizosphere soil.

International journal of systematic and evolutionary microbiology, 62(Pt 11):2589-2592.

A novel actinobacterium, designated strain BR-34(T), was isolated from rhizosphere soil of bamboo (Phyllostachys nigro var. henonis) sampled in Damyang, Korea. The strain was found to have morphological and chemotaxonomic characteristics typical of the genus Catenulispora. The strain contained iso-C(16 : 0) as the major fatty acid and MK-9(H(4)), MK-9(H(6)) and MK-9(H(8)) as major isoprenoid quinones. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain BR-34(T) formed a cluster separate from members of the genus Catenulispora and was related most closely to Catenulispora acidiphila ID139908(T) (97.4% similarity), Catenulispora rubra Aac-30(T) (97.3%), Catenulispora yoronensis TT N02-20(T) (97.3%) and Catenulispora subtropica TT 99-48(T) (97%). However, the level of DNA-DNA relatedness between strain BR-34(T) and C. acidiphila ID139908(T) was only 45.32%. Based on DNA-DNA relatedness, morphological and phenotypic data, strain BR-34(T) could be distinguished from the type strains of phylogenetically related species. It is therefore considered to represent a novel species of the genus Catenulispora, for which the name Catenulispora graminis sp. nov. is proposed. The type strain is BR-34(T) (=KACC 15070(T)=NBRC 107755(T)).

RevDate: 2020-06-03
CmpDate: 2014-05-16

Lee HJ, Han SI, KS Whang (2012)

Streptomyces gramineus sp. nov., an antibiotic-producing actinobacterium isolated from bamboo (Sasa borealis) rhizosphere soil.

International journal of systematic and evolutionary microbiology, 62(Pt 4):856-859.

Two actinobacterial strains, JR-43T and JR-4, were isolated from bamboo (Sasa borealis) rhizosphere soil. The isolates produced grey aerial mycelium and a yellow soluble pigment on ISP 4. Microscopic observation revealed that strains JR-43T and JR-4 produced rectiflexibiles spore chains with spiny surfaces. Both isolates had antibacterial activity against plant-pathogenic bacteria, such as Xanthomonas campestris LMG 568T and Xanthomonas axonopodis pv. vesicatoria LMG 905. The isolates contained iso-C14:0, iso-C15:0, anteiso-C15:0 and iso-C16:0 as the major fatty acids and MK-9(H6) and MK-9(H8) as the major isoprenoid quinones. Phylogenetic analysis of the 16S rRNA gene sequences of strains JR-43T and JR-4 showed that they grouped within Streptomyces cluster II and had highest sequence similarity to Streptomyces seoulensis NBRC 16668T and Streptomyces recifensis NBRC 12813T (both 98.2 % 16S rRNA gene sequence similarity). DNA-DNA relatedness between strain JR-43T and S. seoulensis NBRC 16668T and S. recifensis NBRC 12813T ranged from 31.42 to 42.92 %. Based on DNA-DNA relatedness and morphological and phenotypic data, strains JR-43T and JR-4 could be distinguished from the type strains of phylogenetically related species. They are therefore considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces gramineus sp. nov. is proposed. The type strain is JR-43T (=KACC 15079T=NBRC 107863T). Strain JR-4 (=KACC 15078= NBRC 107864) is a reference strain [corrected].

RevDate: 2020-06-03
CmpDate: 2012-06-06

Han SI, Lee HJ, Lee HR, et al (2012)

Mucilaginibacter polysacchareus sp. nov., an exopolysaccharide-producing bacterial species isolated from the rhizoplane of the herb Angelica sinensis.

International journal of systematic and evolutionary microbiology, 62(Pt 3):632-637.

Three exopolysaccharide-producing bacteria, designated strains DRP28(T), DRP29 and DRP31, were isolated from the rhizoplane of Angelica sinensis from the Geumsan, Republic of Korea. Cells were straight rods, Gram reaction-negative, aerobic, non-motile, and catalase- and oxidase- positive. Flexirubin-type pigments were absent. Phylogenetic analysis of the 16S rRNA gene indicated that these bacteria belong to the genus Mucilaginibacter in the phylum Bacteroidetes. 16S rRNA gene sequence similarities to strains of recognized species of the genus Mucilaginibacter were 93.8-97.4%. The major fatty acids were iso-C(15:0) and summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH). The strains contained MK-7 as the major isoprenoid quinone. Strains DRP28(T), DRP29 and DRP31 formed a single, distinct genomospecies with DNA G+C contents of 41.9-42.7 mol% and DNA hybridization values of 82.6-86.8%; the strains exhibited DNA-DNA hybridization values of only 20.4-41.3% with related species of the genus Mucilaginibacter. On the basis of evidence presented in this study, strains DRP28(T), DRP29 and DRP31 were considered to represent a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter polysacchareus sp. nov. is proposed. The type strain is DRP28(T) (=KACC 15075(T) =NBRC 107757(T)).

RevDate: 2020-06-03
CmpDate: 2012-04-30

Justé A, Van Trappen S, Verreth C, et al (2012)

Characterization of Tetragenococcus strains from sugar thick juice reveals a novel species, Tetragenococcus osmophilus sp. nov., and divides Tetragenococcus halophilus into two subspecies, T. halophilus subsp. halophilus subsp. nov. and T. halophilus subsp. flandriensis subsp. nov.

International journal of systematic and evolutionary microbiology, 62(Pt 1):129-137.

Most bacteria recovered so far from sugar thick juice during storage represent strains of the species Tetragenococcus halophilus. Recently, several Gram-positive, non-motile, non-spore-forming cocci with other physiological and genetic traits were isolated from sugar thick juice samples from different origins. In this study, representative isolates were investigated using a polyphasic taxonomic approach. The 16S rRNA gene sequence similarity between these isolates and their closest relative, Tetragenococcus muriaticus, was 97.4%. The level of DNA-DNA relatedness between isolate T1(T), representing the newly found Tetragenococcus isolates, and T. muriaticus was 57%. Isolate T1(T) had a DNA G+C content of 36.7 mol%. Phylogenetic data and genomic and phenotypic features demonstrated that the isolates represent a novel species, for which the name Tetragenococcus osmophilus sp. nov. is proposed with T1(T) as the type strain (=LMG 26041(T) =DSM 23765(T)). Additionally, T. halophilus isolates from high-salt and high-sugar environments showed clear differences in several physiological and genetic characteristics like RAPD fingerprints and 16S rRNA gene sequences. DNA-DNA hybridizations, however, showed 79 to 80% relatedness between osmophilic and halophilic T. halophilus isolates, demonstrating that the different strains belong to the same species. Based on the phenotypic and genotypic differences observed, as well as the different origins of the strains and the industrial relevance of thick juice degradation, two subspecies of T. halophilus are described in this manuscript: T. halophilus subsp. halophilus subsp. nov. for the strains isolated from salt media and T. halophilus subsp. flandriensis subsp. nov. for the strains isolated from sugar-rich environments, which were first isolated in Flanders, Belgium. The type strains for the subspecies are IAM 1676(T) (=LMG 11490(T) =DSM 20339(T)) and T5(T) (=LMG 26042(T) =DSM 23766(T)), respectively.

RevDate: 2020-06-02

van Bergeijk DA, Terlouw BR, Medema MH, et al (2020)

Ecology and genomics of Actinobacteria: new concepts for natural product discovery.

Nature reviews. Microbiology pii:10.1038/s41579-020-0379-y [Epub ahead of print].

Actinobacteria constitute a highly diverse bacterial phylum with an unrivalled metabolic versatility. They produce most of the clinically used antibiotics and a plethora of other natural products with medical or agricultural applications. Modern 'omics'-based technologies have revealed that the genomic potential of Actinobacteria greatly outmatches the known chemical space. In this Review, we argue that combining insights into actinobacterial ecology with state-of-the-art computational approaches holds great promise to unlock this unexplored reservoir of actinobacterial metabolism. This enables the identification of small molecules and other stimuli that elicit the induction of poorly expressed biosynthetic gene clusters, which should help reinvigorate screening efforts for their precious bioactive natural products.

RevDate: 2020-06-02

Roach TNF, Little M, Arts MGI, et al (2020)

A multiomic analysis of in situ coral-turf algal interactions.

Proceedings of the National Academy of Sciences of the United States of America pii:1915455117 [Epub ahead of print].

Viruses, microbes, and host macroorganisms form ecological units called holobionts. Here, a combination of metagenomic sequencing, metabolomic profiling, and epifluorescence microscopy was used to investigate how the different components of the holobiont including bacteria, viruses, and their associated metabolites mediate ecological interactions between corals and turf algae. The data demonstrate that there was a microbial assemblage unique to the coral-turf algae interface displaying higher microbial abundances and larger microbial cells. This was consistent with previous studies showing that turf algae exudates feed interface and coral-associated microbial communities, often at the detriment of the coral. Further supporting this hypothesis, when the metabolites were assigned a nominal oxidation state of carbon (NOSC), we found that the turf algal metabolites were significantly more reduced (i.e., have higher potential energy) compared to the corals and interfaces. The algae feeding hypothesis was further supported when the ecological outcomes of interactions (e.g., whether coral was winning or losing) were considered. For example, coral holobionts losing the competition with turf algae had higher Bacteroidetes-to-Firmicutes ratios and an elevated abundance of genes involved in bacterial growth and division. These changes were similar to trends observed in the obese human gut microbiome, where overfeeding of the microbiome creates a dysbiosis detrimental to the long-term health of the metazoan host. Together these results show that there are specific biogeochemical changes at coral-turf algal interfaces that predict the competitive outcomes between holobionts and are consistent with algal exudates feeding coral-associated microbes.

RevDate: 2020-06-02

Costa OYA, de Hollander M, Pijl A, et al (2020)

Cultivation-independent and cultivation-dependent metagenomes reveal genetic and enzymatic potential of microbial community involved in the degradation of a complex microbial polymer.

Microbiome, 8(1):76 pii:10.1186/s40168-020-00836-7.

BACKGROUND: Cultivation-independent methods, including metagenomics, are tools for the exploration and discovery of biotechnological compounds produced by microbes in natural environments. Glycoside hydrolases (GHs) enzymes are extremely desired and important in the industry of production for goods and biofuel and removal of problematic biofilms and exopolysaccharide (EPS). Biofilms and EPS are complex, requiring a wide range of enzymes for a complete degradation. The aim of this study was to identify potential GH microbial producers and GH genes with biotechnological potential, using EPS-complex structure (WH15EPS) of Acidobacteria Granulicella sp. strain WH15 as an enrichment factor, in cultivation-independent and cultivation-dependent methods. We performed stable isotope probing (SIP) combined with metagenomics on topsoil litter amended with WH15EPS and coupled solid culture-EPS amended medium with metagenomics.

RESULTS: SIP metagenome analysis of the soil litter demonstrated that phyla Proteobacteria, Actinobacteria, Acidobacteria, and Planctomycetes were the most abundant in WH15EPS amended and unamended treatments. The enrichment cultures in solid culture medium coupled to metagenomics demonstrated an enrichment in Proteobacteria, and the metagenome assembly of this enrichment cultures resulted in 4 metagenome-assembled genomes (MAGs) of microbes with low identity (42-86%) to known microorganisms. Among all carbohydrate-active enzymes (CAZymes) retrieved genes, glycoside transferase (GT) was the most abundant family, either in culture-independent or culture-based metagenome datasets. Within the glycoside hydrolases (GHs), GH13 was the most abundant family in both metagenome datasets. In the "heavy" fraction of the culture-independent metagenome SIP dataset, GH109 (α-N-acetylgalactosaminidases), GH117 (agarases), GH50 (agarases), GH32 (invertases and inulinases), GH17 (endoglucanases), and GH71 (mutanases) families were more abundant in comparison with the controls. Those GH families are affiliated to microorganism that are probably capable to degrade WH15EPS and potentially applicable for biofilm deconstruction. Subsequent in culture-based metagenome, the assembled 4 MAGs (unclassified Proteobacteria) also contained GH families of interest, involving mannosidases, lysozymes, galactosidases, and chitinases.

CONCLUSIONS: We demonstrated that functional diversity induced by the presence of WH15EPS in both culture-independent and culture-dependent approaches was enriched in GHs, such as amylases and endoglucanases that could be applied in chemical, pharmaceutical, and food industrial sectors. Furthermore, WH15EPS may be used for the investigation and isolation of yet unknown taxa, such as unclassified Proteobacteria and Planctomycetes, increasing the number of current cultured bacterial representatives with potential biotechnological traits. Video Abstract.

RevDate: 2020-06-01

Bagnoud A, Pramateftaki P, Bogard MJ, et al (2020)

Microbial Ecology of Methanotrophy in Streams Along a Gradient of CH4 Availability.

Frontiers in microbiology, 11:771.

Despite the recognition of streams and rivers as sources of methane (CH4) to the atmosphere, the role of CH4 oxidation (MOX) in these ecosystems remains poorly understood to date. Here, we measured the kinetics of MOX in stream sediments of 14 sites to resolve the ecophysiology of CH4 oxidizing bacteria (MOB) communities. The streams cover a gradient of land cover and associated physicochemical parameter and differed in stream- and porewater CH4 concentrations. Michealis-Menten kinetic parameter of MOX, maximum reaction velocity (Vmax), and CH4 concentration at half Vmax (KS) increased with CH4 supply. KS values in the micromolar range matched the CH4 concentrations measured in shallow stream sediments and indicate that MOX is mostly driven by low-affinity MOB. 16S rRNA gene sequencing identified MOB classified as Methylococcaceae and particularly Crenothrix. Their relative abundance correlated with pmoA gene counts and MOX rates, underscoring their pivotal role as CH4 oxidizers in stream sediments. Building on the concept of enterotypes, we identify two distinct groups of co-occurring MOB. While there was no taxonomic difference among the members of each cluster, one cluster contained abundant and common MOB, whereas the other cluster contained rare operational taxonomic units (OTUs) specific to a subset of streams. These integrated analyses of changes in MOB community structure, gene abundance, and the corresponding ecosystem process contribute to a better understanding of the distal controls on MOX in streams.

RevDate: 2020-06-01

Zhang Z, van Kleunen M, Becks L, et al (2020)

Towards a General Understanding of Bacterial Interactions.

Trends in microbiology pii:S0966-842X(20)30136-0 [Epub ahead of print].

Understanding the general rules of microbial interactions is central for advancing microbial ecology. Recent studies show that interaction range, interaction strength, and community context determine bacterial interactions and the coexistence and evolution of bacteria. We highlight how these factors could contribute to a general understanding of bacterial interactions.

RevDate: 2020-06-01

Sedighian N, Krijger M, Taparia T, et al (2020)

Genome Resource of Two Potato Strains of Ralstonia solanacearum Biovar 2 (Phylotype IIB Sequevar 1) and Biovar 2T (Phylotype IIB Sequevar 25) Isolated from Lowlands in Iran.

Molecular plant-microbe interactions : MPMI [Epub ahead of print].

Ralstonia solanacearum, the causal agent of bacterial wilt and brown rot disease, is one of the major pathogens of solanaceous crops, including potato, around the globe. Biovar 2T (phylotype II/sequevar 25) of R. solanacearum is adapted to tropical lowlands and is only reported in South America and Iran. Thus far, no genome resource of the biovar 2T of the pathogen has been available. Here, we present the near-complete genome sequences of the biovar 2T strain CFBP 8697 as well as strain CFBP 8695 belonging to biovar 2 race 3, both isolated from potato in Iran. The genomic data of biovar 2T will extend our understanding of the virulence features of R. solanacearum and pave the way for research on biovar 2T functional and interaction genetics.

RevDate: 2020-05-31

Musonerimana S, Bez C, Licastro D, et al (2020)

Pathobiomes Revealed that Pseudomonas fuscovaginae and Sarocladium oryzae Are Independently Associated with Rice Sheath Rot.

Microbial ecology pii:10.1007/s00248-020-01529-2 [Epub ahead of print].

Rice sheath rot has been mainly associated with the bacterial pathogen Pseudomonas fuscovaginae and in some cases to the fungal pathogen Sarocladium oryzae; it is yet unclear if they are part of a complex disease. The bacterial and fungal community associated with rice sheath rot symptomatic and asymptomatic rice plants was determined/studied with the main aim to shed light on the pathogen(s) causing rice sheath rot. Plant samples were collected from different rice varieties in two locations (highland and lowland) in two rice-growing seasons (wet and dry season) in Burundi. Our results showed that the bacterial Pseudomonas genus was prevalent in highland in both rice-growing seasons and was not affected by rice plant varieties. Pseudomonas sequence reads displayed a significant high similarity to Pseudomonas fuscovaginae indicating that it is the causal agent of rice sheath rot as previously reported. The fungal Sarocladium genus was on the other hand prevalent in lowland only in the wet season; the sequence reads were most significantly similar to Sarocladium oryzae. These studies showed that plant microbiome analysis is very useful in determining the microorganisms involved in a plant disease. P. fuscovaginae and S. oryzae were prevalent in symptomatic samples in highland and lowland respectively being present independently and hence are not part of a complex disease. The significant presence of other bacterial and fungal taxa in symptomatic samples is also discussed possibly making this disease more complex. Finally, we also report the microbial communities that are associated with the plant sheath in symptomatic and asymptomatic plants from the same rice fields.

RevDate: 2020-05-31

Liu RR, Tian Y, Zhou EM, et al (2020)

Distinct Expression of the Two NO-Forming Nitrite Reductases in Thermus antranikianii DSM 12462T Improved Environmental Adaptability.

Microbial ecology pii:10.1007/s00248-020-01528-3 [Epub ahead of print].

Hot spring ecosystems are analogous to some thermal environments on the early Earth and represent ideal models to understand life forms and element cycling on the early Earth. Denitrification, an important component of biogeochemical nitrogen cycle, is highly active in hot springs. Nitrite (NO2-) reduction to nitric oxide (NO) is the significant and rate-limiting pathway in denitrification and is catalyzed by two types of nitrite reductases, encoded by nirS and nirK genes. NirS and NirK were originally considered incompatible in most denitrifying organisms, although a few strains have been reported to possess both genes. Herein, we report the functional division of nirS and nirK in Thermus, a thermophilic genus widespread in thermal ecosystems. Transcriptional levels of nirS and nirK coexisting in Thermus antranikianii DSM 12462T were measured to assess the effects of nitrite, oxygen, and stimulation time. Thirty-nine Thermus strains were used to analyze the phylogeny and distribution of nirS and nirK; six representative strains were used to assess the denitrification phenotype. The results showed that both genes were actively transcribed and expressed independently in T. antranikianii DSM 12462T. Strains with both nirS and nirK had a wider range of nitrite adaptation and revealed nir-related physiological adaptations in Thermus: nirK facilitated adaptation to rapid changes and extended the adaptation range of nitrite under oxygen-limited conditions, while nirS expression was higher under oxic and relatively stable conditions.

RevDate: 2020-05-30

Su L, Zhang L, Nie D, et al (2020)

Bacterial Tomato Pathogen Ralstonia solanacearum Invasion Modulates Rhizosphere Compounds and Facilitates the Cascade Effect of Fungal Pathogen Fusarium solani.

Microorganisms, 8(6): pii:microorganisms8060806.

Soil-borne pathogen invasions can significantly change the microbial communities of the host rhizosphere. However, whether bacterial Ralstonia solanacearum pathogen invasion influences the abundance of fungal pathogens remains unclear. In this study, we combined high-throughput sequencing, qPCR, liquid chromatography and soil culture experiments to analyze the rhizosphere fungal composition, co-occurrence of fungal communities, copy numbers of functional genes, contents of phenolic acids and their associations in healthy and bacterial wilt-diseased tomato plants. We found that R. solanacearum invasion increased the abundance of the soil-borne pathogen Fusarium solani. The concentrations of three phenolic acids in the rhizosphere soil of bacterial wilt-diseased tomato plants were significantly higher than those in the rhizosphere soil of healthy tomato plants. In addition, the increased concentrations of phenolic acids significantly stimulated F. solani growth in the soil. Furthermore, a simple fungal network with fewer links, nodes and hubs (highly connected nodes) was found in the diseased tomato plant rhizosphere. These results indicate that once the symptom of bacterial wilt disease is observed in tomato, the roots of the wilt-diseased tomato plants need to be removed in a timely manner to prevent the enrichment of other fungal soil-borne pathogens. These findings provide some ecological clues for the mixed co-occurrence of bacterial wilt disease and other fungal soil-borne diseases.

RevDate: 2020-05-29

Capson-Tojo G, Batstone DJ, Grassino M, et al (2020)

Purple phototrophic bacteria for resource recovery: Challenges and opportunities.

Biotechnology advances pii:S0734-9750(20)30064-1 [Epub ahead of print].

Sustainable development is driving a rapid focus shift in the wastewater and organic waste treatment sectors, from a "removal and disposal" approach towards the recovery and reuse of water, energy and materials (e.g. carbon or nutrients). Purple phototrophic bacteria (PPB) are receiving increasing attention due to their capability of growing photoheterotrophically under anaerobic conditions. Using light as energy source, PPB can simultaneously assimilate carbon and nutrients at high efficiencies (with biomass yields close to unity (1 g CODbiomass·g CODremoved-1)), facilitating the maximum recovery of these resources as different value-added products. The effective use of infrared light enables selective PPB enrichment in non-sterile conditions, without competition with other phototrophs such as microalgae if ultraviolet-visible wavelengths are filtered. This review reunites results systematically gathered from over 177 scientific articles, aiming at producing generalized conclusions. The most critical aspects of PPB-based production and valorisation processes are addressed, including: (i) the identification of the main challenges and potentials of different growth strategies, (ii) a critical analysis of the production of value-added compounds, (iii) a comparison of the different value-added products, (iv) insights into the general challenges and opportunities and (v) recommendations for future research and development towards practical implementation. To date, most of the work has not been executed under real-life conditions, relevant for full-scale application. With the savings in wastewater discharge due to removal of organics, nitrogen and phosphorus as an important economic driver, priorities must go to using PPB-enriched cultures and real waste matrices. The costs associated with artificial illumination, followed by centrifugal harvesting/dewatering and drying, are estimated to be 1.9, 0.3-2.2 and 0.1-0.3 $·kgdry biomass-1. At present, these costs are likely to exceed revenues. Future research efforts must be carried out outdoors, using sunlight as energy source. The growth of bulk biomass on relatively clean wastewater streams (e.g. from food processing) and its utilization as a protein-rich feed (e.g. to replace fishmeal, 1.5-2.0 $·kg-1) appears as a promising valorisation route.

RevDate: 2020-05-29

Rampal R, Wari N, Singh AK, et al (2020)

Retinoic Acid Is Elevated in the Mucosa of Patients With Active Ulcerative Colitis and Displays a Proinflammatory Role by Augmenting IL-17 and IFNγ Production.

Inflammatory bowel diseases pii:5848464 [Epub ahead of print].

BACKGROUND: All-trans retinoic acid (RA) plays a crucial role in promoting Foxp3+ Treg generation while reciprocally inhibiting Th1/Th17 generation. Our previous research highlighted that in the face of inflammatory conditions, RA plays a contrary role where it aggravates intestinal inflammation by promoting interferon (IFN) γ and interleukin (IL)-17 differentiation in vitro.

METHODS: In this study we translated our in vitro results into a clinical setting where we estimated mucosal and serum RA levels along with the immunophenotypic profile (IL-17, IFNγ, Foxp3, IL-10) in adaptive (CD4, CD8) and innate-like T cells (mucosal associated invariant T cells and γδ T cells) in patients with ulcerative colitis in remission or with active inflammation.

RESULTS: This is the first study to estimate RA levels in the human gut and shows that patients with active disease had increased mucosal RA levels as compared with patients in remission (4.0 vs 2.5 ng/mL; P < 0.01) and control patients (3.4 vs 0.8 ng/mL; P < 0.0001). This effect was accompanied by significantly elevated IL-17 and IFNγ in tissue CD4+, CD8+, mucosal associated invariant T+ cells, and γδ + T cells. Moreover, the raised RA levels in patients with active disease showed a positive correlation with proinflammatory cytokines (IL-17, IFNγ) and a negative correlation with IL-10. We also found that RA negatively correlated with IL-9, thereby reinstating our previous finding that RA inhibits Th9 differentiation.

CONCLUSIONS: These data confirm our previous in vitro results that in the presence of inflammation, RA plays a crucial role in maintaining gut inflammation by upregulating proinflammatory markers.

RevDate: 2020-05-29

Tschoeke D, Salazar VW, Vidal L, et al (2020)

Unlocking the Genomic Taxonomy of the Prochlorococcus Collective.

Microbial ecology pii:10.1007/s00248-020-01526-5 [Epub ahead of print].

Prochlorococcus is the most abundant photosynthetic prokaryote on our planet. The extensive ecological literature on the Prochlorococcus collective (PC) is based on the assumption that it comprises one single genus comprising the species Prochlorococcus marinus, containing itself a collective of ecotypes. Ecologists adopt the distributed genome hypothesis of an open pan-genome to explain the observed genomic diversity and evolution patterns of the ecotypes within PC. Novel genomic data for the PC prompted us to revisit this group, applying the current methods used in genomic taxonomy. As a result, we were able to distinguish the five genera: Prochlorococcus, Eurycolium, Prolificoccus, Thaumococcus, and Riococcus. The novel genera have distinct genomic and ecological attributes.

RevDate: 2020-05-29

Van den Abbeele P, Ghyselinck J, Marzorati M, et al (2020)

In Vitro Evaluation of Prebiotic Properties of a Commercial Artichoke Inflorescence Extract Revealed Bifidogenic Effects.

Nutrients, 12(6): pii:nu12061552.

: Background: Prebiotics used as a dietary supplement, stimulate health-related gut microbiota (e.g., bifidobacteria, lactobacilli, etc.). This study evaluated potential prebiotic effects of an artichoke aqueous dry extract (AADE) using in vitro gut model based on the Simulator of Human Intestinal Microbial Ecosystem (SHIME®).

METHODS: Short-term colonic fermentations (48 h) of AADE, fructo-oligosaccharides (FOS), and a blank were performed. Microbial metabolites were assessed at 0, 6, 24, and 48 h of colonic incubation via measuring pH, gas pressure, lactate, ammonium, and short-chain fatty acids (SCFAs) levels. Community composition was assessed via targeted qPCRs.

RESULTS: After 24 and 48 h of incubation, bifidobacteria levels increased 25-fold with AADE (p < 0.05) and >100-fold with FOS (p < 0.05) compared to blank. Lactobacillus spp. levels only tended to increase with AADE, whereas they increased 10-fold with FOS. At 6 h, pH decreased with AADE and FOS and remained stable until 48 h; however, gas pressure increased significantly till the end of study. Acetate, propionate, and total SCFA production increased significantly with both at all time-points. Lactate levels initially increased but branched SCFA and ammonium levels remained low till 48 h.

CONCLUSION: AADE displayed prebiotic potential by exerting bifidogenic effects that stimulated production of health-related microbial metabolites, which is potentially due to inulin in AADE.

RevDate: 2020-05-29

Jia X, Dini-Andreote F, J Falcão Salles (2020)

Comparing the Influence of Assembly Processes Governing Bacterial Community Succession Based on DNA and RNA Data.

Microorganisms, 8(6): pii:microorganisms8060798.

Quantifying which assembly processes structure microbiomes can assist prediction, manipulation, and engineering of community outcomes. However, the relative importance of these processes might depend on whether DNA or RNA are used, as they differ in stability. We hypothesized that. RNA-inferred community responses to (a)biotic fluctuations are faster than those inferred by DNA; the relative influence of variable selection is stronger in RNA-inferred communities (environmental factors are spatiotemporally heterogeneous), whereas homogeneous selection largely influences DNA-inferred communities (environmental filters are constant). To test these hypotheses, we characterized soil bacterial communities by sequencing both 16S rRNA amplicons from the extracted DNA and RNA transcripts across distinct stages of soil primary succession and quantified the relative influence of each assembly process using ecological null model analysis. Our results revealed that variations in α-diversity and temporal turnover were higher in RNA- than in DNA-inferred communities across successional stages, albeit there was a similar community composition; in line with our hypotheses, the assembly of RNA-inferred community was more closely associated with environmental variability (variable selection) than using the standard DNA-based approach, which was largely influenced by homogeneous selection. This study illustrates the need for benchmarking approaches to properly elucidate how community assembly processes structure microbial communities.

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 https://github.com/hk1785/MiHC.

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.

LOAD NEXT 100 CITATIONS

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 @ gmail.com

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).

Timelines

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

Biographies

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 )