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Bibliography on: Symbiosis

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ESP: PubMed Auto Bibliography 25 Oct 2020 at 01:50 Created: 


Symbiosis refers to an interaction between two or more different organisms living in close physical association, typically to the advantage of both. Symbiotic relationships were once thought to be exceptional situations. Recent studies, however, have shown that every multicellular eukaryote exists in a tight symbiotic relationship with billions of microbes. The associated microbial ecosystems are referred to as microbiome and the combination of a multicellular organism and its microbiota has been described as a holobiont. It seems "we are all lichens now."

Created with PubMed® Query: symbiosis NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)


RevDate: 2020-10-24

Palmer TM, Riginos C, Milligan PD, et al (2020)

Frenemy at the gate: invasion by Pheidole megacephala facilitates a competitively subordinate plant ant in Kenya.

Ecology [Epub ahead of print].

Biological invasions can lead to the reassembly of communities, and understanding and predicting the impacts of exotic species on community structure and functioning is a key challenge in ecology. We investigated the impact of a predatory species of invasive ant, Pheidole megacephala, on the structure and function of a foundational mutualism between Acacia drepanolobium and its associated acacia-ant community in an East African savanna. Invasion by P. megacephala was associated with the extirpation of three extrafloral nectar-dependent Crematogaster acacia ant species and strong increases in the abundance of a competitively subordinate and locally rare acacia ant species, Tetraponera penzigi, which does not depend on host plant nectar. Using a combination of long-term monitoring of invasion dynamics, observations and experiments, we demonstrate that P. megacephala directly and indirectly facilitates T. penzigi by reducing the abundance of T. penzigi's competitors (Crematogaster spp), imposing recruitment limitation on these competitors, and generating a landscape of low-reward host plants that favor colonization and establishment by the strongly dispersing T. penzigi. Seasonal variation in use of host plants by P. megacephala may further increase the persistence of T. penzigi colonies in invaded habitat. The persistence of the T. penzigi-A. drepanolobium symbiosis in invaded areas afforded host plants some protection against herbivory by elephants (Loxodonta africana), a key browser that reduces tree cover. However, elephant damage on T. penzigi-occupied trees was higher in invaded than in uninvaded areas, likely owing to reduced T. penzigi colony size in invaded habitats. Our results reveal the mechanisms underlying the disruption of this mutualism and suggest that P. megacephala invasion may drive long-term declines in tree cover, despite the partial persistence of the ant-acacia symbiosis in invaded areas.

RevDate: 2020-10-24

Jackrel SL, Yang JW, Schmidt KC, et al (2020)

Host specificity of microbiome assembly and its fitness effects in phytoplankton.

The ISME journal pii:10.1038/s41396-020-00812-x [Epub ahead of print].

Insights into symbiosis between eukaryotic hosts and their microbiomes have shifted paradigms on what determines host fitness, ecology, and behavior. Questions remain regarding the roles of host versus environment in shaping microbiomes, and how microbiome composition affects host fitness. Using a model system in ecology, phytoplankton, we tested whether microbiomes are host-specific, confer fitness benefits that are host-specific, and remain conserved in time in their composition and fitness effects. We used an experimental approach in which hosts were cleaned of bacteria and then exposed to bacterial communities from natural environments to permit recruitment of microbiomes. We found that phytoplankton microbiomes consisted of a subset of taxa recruited from these natural environments. Microbiome recruitment was host-specific, with host species explaining more variation in microbiome composition than environment. While microbiome composition shifted and then stabilized over time, host specificity remained for dozens of generations. Microbiomes increased host fitness, but these fitness effects were host-specific for only two of the five species. The shifts in microbiome composition over time amplified fitness benefits to the hosts. Overall, this work solidifies the importance of host factors in shaping microbiomes and elucidates the temporal dynamics of microbiome compositional and fitness effects.

RevDate: 2020-10-24

Aschtgen MS, Brennan CA, Nikolakakis K, et al (2019)

Insights into flagellar function and mechanism from the squid-vibrio symbiosis.

NPJ biofilms and microbiomes, 5(1):32 pii:10.1038/s41522-019-0106-5.

Flagella are essential and multifunctional nanomachines that not only move symbionts towards their tissue colonization site, but also play multiple roles in communicating with the host. Thus, untangling the activities of flagella in reaching, interacting, and signaling the host, as well as in biofilm formation and the establishment of a persistent colonization, is a complex problem. The squid-vibrio system offers a unique model to study the many ways that bacterial flagella can influence a beneficial association and, generally, other bacteria-host interactions. Vibrio fischeri is a bioluminescent bacterium that colonizes the Hawaiian bobtail squid, Euprymna scolopes. Over the last 15 years, the structure, assembly, and functions of V. fischeri flagella, including not only motility and chemotaxis, but also biofilm formation and symbiotic signaling, have been revealed. Here we discuss these discoveries in the perspective of other host-bacteria interactions.

RevDate: 2020-10-23

Li M, Liu H, Guo Y, et al (2020)

Single symbiotic cell transcriptome sequencing of coral.

Genomics pii:S0888-7543(20)31978-9 [Epub ahead of print].

Zooxanthellae and coral can form an intracellular symbiotic system. Yet, little is known about the molecular mechanism underlying this symbiosis. In this study, we characterized the symbiosis based on analyses of gene expression at the single-cell level. Among 9110 single coral cells, we identified 4871 symbiotic cells based on the detection of both coral and zooxanthellae gene transcripts within a single cell. Using the bioinformatics tool Seurat, symbiotic cells were further clustered into five groups, 52 genes exhibited differential expression between groups. We proposed an index called the "symbiosis index", to indicate the degree of gene expression of both species in a single symbiotic cell. Interestingly, the index differed distinctly among the five groups. The symbiosis index was highly correlated with the expression of the coral gene gfas1.m1.6761 (ANKRD40), which encodes ankyrin repeat domain-containing protein 40 and is involved in DNA replication (r = 0.76). Two metabolism-related genes, DAGLA and betaGlu, were highly expressed in cells with a high symbiosis index. Four zooxanthellae genes, PRPF19, ATRN, aAA-ATPases and AK812-SmicGene44833, exhibited substantial changes in expression levels when zooxanthellae lived within coral. A trajectory analysis suggested that cells with a higher symbiosis index may be derived from those with a lower index during coral colony development. Taken together, our results provide evidence for zooxanthellae residing within coral, forming a symbiotic system. The symbiosis index is an effective indicator of different cell groups, with lineage relationships among groups. Additionally, we identified specific genes that exhibit expression changes in the symbiotic system.

RevDate: 2020-10-23

Morais LH, Schreiber HL, SK Mazmanian (2020)

The gut microbiota-brain axis in behaviour and brain disorders.

Nature reviews. Microbiology pii:10.1038/s41579-020-00460-0 [Epub ahead of print].

In a striking display of trans-kingdom symbiosis, gut bacteria cooperate with their animal hosts to regulate the development and function of the immune, metabolic and nervous systems through dynamic bidirectional communication along the 'gut-brain axis'. These processes may affect human health, as certain animal behaviours appear to correlate with the composition of gut bacteria, and disruptions in microbial communities have been implicated in several neurological disorders. Most insights about host-microbiota interactions come from animal models, which represent crucial tools for studying the various pathways linking the gut and the brain. However, there are complexities and manifest limitations inherent in translating complex human disease to reductionist animal models. In this Review, we discuss emerging and exciting evidence of intricate and crucial connections between the gut microbiota and the brain involving multiple biological systems, and possible contributions by the gut microbiota to neurological disorders. Continued advances from this frontier of biomedicine may lead to tangible impacts on human health.

RevDate: 2020-10-23

Batstone RT, O'Brien AM, Harrison TL, et al (2020)

Experimental evolution makes microbes more cooperative with their local host genotype.

Science (New York, N.Y.), 370(6515):476-478.

Advances in microbiome science require a better understanding of how beneficial microbes adapt to hosts. We tested whether hosts select for more-cooperative microbial strains with a year-long evolution experiment and a cross-inoculation experiment designed to explore how nitrogen-fixing bacteria (rhizobia) adapt to legumes. We paired the bacterium Ensifer meliloti with one of five Medicago truncatula genotypes that vary in how strongly they "choose" bacterial symbionts. Independent of host choice, E. meliloti rapidly adapted to its local host genotype, and derived microbes were more beneficial when they shared evolutionary history with their host. This local adaptation was mostly limited to the symbiosis plasmids, with mutations in putative signaling genes. Thus, cooperation depends on the match between partner genotypes and increases as bacteria adapt to their local host.

RevDate: 2020-10-23

Bergstrom K, Shan X, Casero D, et al (2020)

Proximal colon-derived O-glycosylated mucus encapsulates and modulates the microbiota.

Science (New York, N.Y.), 370(6515):467-472.

Colon mucus segregates the intestinal microbiota from host tissues, but how it organizes to function throughout the colon is unclear. In mice, we found that colon mucus consists of two distinct O-glycosylated entities of Muc2: a major form produced by the proximal colon, which encapsulates the fecal material including the microbiota, and a minor form derived from the distal colon, which adheres to the major form. The microbiota directs its own encapsulation by inducing Muc2 production from proximal colon goblet cells. In turn, O-glycans on proximal colon-derived Muc2 modulate the structure and function of the microbiota as well as transcription in the colon mucosa. Our work shows how proximal colon control of mucin production is an important element in the regulation of host-microbiota symbiosis.

RevDate: 2020-10-23

Marczak M, Wójcik M, Żebracki K, et al (2020)

PssJ Is a Terminal Galactosyltransferase Involved in the Assembly of the Exopolysaccharide Subunit in Rhizobium Leguminosarum bv. Trifolii.

International journal of molecular sciences, 21(20): pii:ijms21207764.

Rhizobium leguminosarum bv. trifolii produces exopolysaccharide (EPS) composed of glucose, glucuronic acid, and galactose residues at a molar ratio 5:2:1. A majority of genes involved in the synthesis, modification, and export of exopolysaccharide are located in the chromosomal Pss-I region. In the present study, a ΔpssJ deletion mutant was constructed and shown to produce EPS lacking terminal galactose in the side chain of the octasaccharide subunit. The lack of galactose did not block EPS subunit translocation and polymerization. The in trans delivery of the pssJ gene restored the production of galactose-containing exopolysaccharide. The mutant was compromised in several physiological traits, e.g., motility and biofilm production. An impact of the pssJ mutation and changed EPS structure on the symbiotic performance was observed as improper signaling at the stage of molecular recognition, leading to formation of a significant number of non-infected empty nodules. Terminal galactosyltransferase PssJ was shown to display a structure typical for the GT-A class of glycosyltransferases and interact with other GTs and Wzx/Wzy system proteins. The latter, together with PssJ presence in soluble and membrane protein fractions indicated that the protein plays its role at the inner membrane interface and as a component of a larger complex.

RevDate: 2020-10-23

Engl T, Schmidt THP, Kanyile SN, et al (2020)

Metabolic Cost of a Nutritional Symbiont Manifests in Delayed Reproduction in a Grain Pest Beetle.

Insects, 11(10): pii:insects11100717.

Animals engage in a plethora of mutualistic interactions with microorganisms that can confer various benefits to their host but can also incur context-dependent costs. The sawtoothed grain beetle Oryzaephilus surinamensis harbors nutritional, intracellular Bacteroidetes bacteria that supplement precursors for the cuticle synthesis and thereby enhance desiccation resistance of its host. Experimental elimination of the symbiont impairs cuticle formation and reduces fitness under desiccation stress but does not disrupt the host's life cycle. For this study, we first demonstrated that symbiont populations showed the strongest growth at the end of metamorphosis and then declined continuously in males, but not in females. The symbiont loss neither impacted the development time until adulthood nor adult mortality or lifespan. Furthermore, lifetime reproduction was not influenced by the symbiont presence. However, symbiotic females started to reproduce almost two weeks later than aposymbiotic ones. Thus, symbiont presence incurs a metabolic and context-dependent fitness cost to females, probably due to a nutrient allocation trade-off between symbiont growth and sexual maturation. The O. surinamensis symbiosis thereby represents an experimentally amenable system to study eco-evolutionary dynamics under variable selection pressures.

RevDate: 2020-10-23
CmpDate: 2020-10-23

Hwang IY, MW Chang (2020)

Engineering commensal bacteria to rewire host-microbiome interactions.

Current opinion in biotechnology, 62:116-122.

There has been a growing emphasis on understanding the important relationship between human-associated microbial communities and disease development. With technological advancements, we are able to gain further insights into host-microbiome interactions at a deeper level. In order to fully leverage the close associations between microbes and their host, development of therapeutics targeting the microbiome has surged in recent years. In this review, we discuss advances made in engineering gut bacteria to develop novel therapeutic modalities that aim to rewire host-microbiome interactions such as host metabolism and immune functions for prevention and treatment of various diseases. In particular, applications of these engineered bacteria against diseases such as metabolic, immune disorders and cancer are covered.

RevDate: 2020-10-23
CmpDate: 2020-10-23

Erban T, Sopko B, Kadlikova K, et al (2019)

Varroa destructor parasitism has a greater effect on proteome changes than the deformed wing virus and activates TGF-β signaling pathways.

Scientific reports, 9(1):9400 pii:10.1038/s41598-019-45764-1.

Honeybee workers undergo metamorphosis in capped cells for approximately 13 days before adult emergence. During the same period, Varroa mites prick the defenseless host many times. We sought to identify proteome differences between emerging Varroa-parasitized and parasite-free honeybees showing the presence or absence of clinical signs of deformed wing virus (DWV) in the capped cells. A label-free proteomic analysis utilizing nanoLC coupled with an Orbitrap Fusion Tribrid mass spectrometer provided a quantitative comparison of 2316 protein hits. Redundancy analysis (RDA) showed that the combination of Varroa parasitism and DWV clinical signs caused proteome changes that occurred in the same direction as those of Varroa alone and were approximately two-fold higher. Furthermore, proteome changes associated with DWV signs alone were positioned above Varroa in the RDA. Multiple markers indicate that Varroa activates TGF-β-induced pathways to suppress wound healing and the immune response and that the collective action of stressors intensifies these effects. Furthermore, we indicate JAK/STAT hyperactivation, p53-BCL-6 feedback loop disruption, Wnt pathway activation, Wnt/Hippo crosstalk disruption, and NF-κB and JAK/STAT signaling conflict in the Varroa-honeybee-DWV interaction. These results illustrate the higher effect of Varroa than of DWV at the time of emergence. Markers for future research are provided.

RevDate: 2020-10-23
CmpDate: 2020-10-23

Slattery M, Pankey MS, MP Lesser (2019)

Annual Thermal Stress Increases a Soft Coral's Susceptibility to Bleaching.

Scientific reports, 9(1):8064 pii:10.1038/s41598-019-44566-9.

Like scleractinian corals, soft corals contain photosymbionts (Family Symbiodiniaceae) that provide energy for the host. Recent thermal events have resulted in soft coral bleaching in four of five years on Guam, where they dominated back-reef communities. Soft coral bleaching was examined in Sinularia maxima, S. polydactyla, and their hybrid S. maxima x polydactyla. Results from annual field surveys indicated that S. maxima and the hybrid were more susceptible to bleaching than S. polydactyla, and this was related to differences in their Symbiodiniaceae communities in 2016 and 2017. The photosymbionts of S. polydactyla were apparently more stress tolerant and maintained higher photosynthetic potential through three years of bleaching, in contrast to the other species that exhibited a decline in photosynthetic potential after the first year of bleaching. Nonetheless, by the 2017 bleaching event all soft coral populations exhibited significant bleaching-mediated declines and loss of photosynthetic efficiency suggesting a declining resiliency to annual thermal stress events. While S. polydactyla initially looked to succeed the other species as the dominant space occupying soft coral on Guam back-reefs, cumulative bleaching events ultimately turned this "winner" into a "loser", suggesting the trajectory for coral reefs is towards continued loss of structure and function.

RevDate: 2020-10-23
CmpDate: 2020-10-23

Dunphy CM, Gouhier TC, Chu ND, et al (2019)

Structure and stability of the coral microbiome in space and time.

Scientific reports, 9(1):6785 pii:10.1038/s41598-019-43268-6.

Although it is well established that the microbial communities inhabiting corals perform key functions that promote the health and persistence of their hosts, little is known about their spatial structure and temporal stability. We examined the natural variability of microbial communities associated with six Caribbean coral species from three genera at four reef sites over one year. We identified differences in microbial community composition between coral genera and species that persisted across space and time, suggesting that local host identity likely plays a dominant role in structuring the microbiome. However, we found that microbial community dissimilarity increased with geographical distance, which indicates that regional processes such as dispersal limitation and spatiotemporal environmental heterogeneity also influence microbial community composition. In addition, network analysis revealed that the strength of host identity varied across coral host genera, with species from the genus Acropora having the most influence over their microbial community. Overall, our results demonstrate that despite high levels of microbial diversity, coral species are characterized by signature microbiomes that are stable in both space and time.

RevDate: 2020-10-22

McPolin MC, JM Kranabetter (2020)

Influence of endemic versus cosmopolitan species on the local assembly of ectomycorrhizal fungal communities.

An enduring question of community ecology is how remarkably speciose communities can coexist, particularly in light of competitive exclusion (Hutchinson, 1961). Ectomycorrhizal fungal (EMF) communities are no exception to this paradox; in a survey of old-growth Pseudotsuga menziesii stands, Kranabetter et al. (2018) reported a metacommunity (γ diversity or regional species pool) of approximately 360 EMF species on mesotrophic sites across a single watershed. Efforts to experimentally test EMF species interactions and community assembly can be insightful, but also hampered by the sheer number of taxa and difficulties in culturing an obligatory symbiosis under laboratory conditions (Kennedy, 2010; Branco, 2019). Similarly, the quantification of key morphological traits related to species distribution patterns, such as spore size and shape, can be instructive but inconclusive (Halbwachs et al., 2015; Kilvin, 2020). Given the challenges involved in an inductive approach, it may be advisable to employ perspectives from broader theoretical models to better understand the assembly of this ecologically important group. In this essay we describe how distinctions in geographical range for EMF species (regional to continental) can be used to better understand spatial processes governing local community assembly.

RevDate: 2020-10-22

Kidaj D, Krysa M, Susniak K, et al (2020)

Biological activity of Nod factors.

Acta biochimica Polonica pii:5353 [Epub ahead of print].

Chemically, the Nod factors (NFs) are lipochitooligosaccharides, produced mainly by bacteria of the Rhizobium genus. They are the main signaling molecules involved in the initiation of symbiosis between rhizobia and legume plants. Nod factors affect plant tissues at very low concentrations, even as low as 10-12 mol/L. They induce root hair deformation, cortical cell division, and root nodules' formation in the host plant. At the molecular level, the cytoskeleton is reorganized and expression of genes encoding proteins called nodulins is induced in response to Nod factors in the cell. Action of Nod factors is highly specific because it depends on the structure of a particular Nod factor involved, as well as the plant receptor reacting with it.

RevDate: 2020-10-22

Suzuki M, Numazaki R, Nakagawa T, et al (2020)

Cytoplasmic interaction of LysM receptors contributes to the formation of symbiotic receptor complex.

Plant biotechnology (Tokyo, Japan), 37(3):359-362.

Receptor complex formation at the cell surface is a key step to initiate downstream signaling but the contribution of this process for the regulation of the direction of downstream responses is not well understood. In the plant-microbe interactions, while CERK1, an Arabidopsis LysM-RLK, mediates chitin-induced immune responses, NFR1, a Lotus homolog of CERK1, regulates the symbiotic process with rhizobial bacteria through the recognition of Nod factors. Concerning the mechanistic insight of the regulation of such apparently opposite biological responses by the structurally related RLKs, Nakagawa et al. previously showed that the addition of YAQ sequence, conserved in NFR1 and other symbiotic LysM-RLKs, to the kinase domain of CERK1 switched downstream responses from defense to symbiosis using a set of chimeric receptors, NFR1-CERK1s. These results indicated that such a subtle difference in the cytoplasmic domain of LysM-RLKs could determine the direction of host responses from defense to symbiosis. On the other hand, it is still not understood how such structural differences in the cytoplasmic domains determine the direction of host responses. We here analyzed the interaction between chimeric NFR1s and NFR5, a partner receptor of NFR1, by co-immunoprecipitation (Co-IP) of these proteins transiently expressed in Nicotiana benthamiana. These results indicated that the cytoplasmic interaction between the LysM-RLKs is important for the symbiotic receptor complex formation and the YAQ containing region of NFR1 contributes to trigger symbiotic signaling through the successful formation of NFR1/NFR5 complex.

RevDate: 2020-10-22

Mason RAB, Wall CB, Cunning R, et al (2020)

High light alongside elevated PCO2 alleviates thermal depression of photosynthesis in a hard coral (Pocillopora acuta).

The Journal of experimental biology, 223(Pt 20): pii:223/20/jeb223198.

The absorbtion of human-emitted CO2 by the oceans (elevated PCO2) is projected to alter the physiological performance of coral reef organisms by perturbing seawater chemistry (i.e. ocean acidification). Simultaneously, greenhouse gas emissions are driving ocean warming and changes in irradiance (through turbidity and cloud cover), which have the potential to influence the effects of ocean acidification on coral reefs. Here, we explored whether physiological impacts of elevated PCO2 on a coral-algal symbiosis (Pocillopora acuta-Symbiodiniaceae) are mediated by light and/or temperature levels. In a 39 day experiment, elevated PCO2 (962 versus 431 µatm PCO2) had an interactive effect with midday light availability (400 versus 800 µmol photons m-2 s-1) and temperature (25 versus 29°C) on areal gross and net photosynthesis, for which a decline at 29°C was ameliorated under simultaneous high-PCO2 and high-light conditions. Light-enhanced dark respiration increased under elevated PCO2 and/or elevated temperature. Symbiont to host cell ratio and chlorophyll a per symbiont increased at elevated temperature, whilst symbiont areal density decreased. The ability of moderately strong light in the presence of elevated PCO2 to alleviate the temperature-induced decrease in photosynthesis suggests that higher substrate availability facilitates a greater ability for photochemical quenching, partially offsetting the impacts of high temperature on the photosynthetic apparatus. Future environmental changes that result in moderate increases in light levels could therefore assist the P. acuta holobiont to cope with the 'one-two punch' of rising temperatures in the presence of an acidifying ocean.

RevDate: 2020-10-21

Tang J, Wu Z, Wan L, et al (2020)

Differential enrichment and physiological impacts of ingested microplastics in scleractinian corals in situ.

Journal of hazardous materials, 404(Pt B):124205 pii:S0304-3894(20)32195-6 [Epub ahead of print].

Microplastics are emerging contaminants and widespread in the ocean, but their impacts on coral reef ecosystems are poorly understood, and in situ study is still lacking. In the present study, the distribution patterns of microplastics in the environment and inhabiting organisms were investigated along the east coast of Hainan Island, South China Sea, and the physiological impacts of the microplastics on scleractinian corals were analyzed. We documented average microplastic concentrations of 14.90 particlesL-1 in seawater, 343.04 particleskg-1 in sediment, 4.97 particlescm-2 in corals, and 0.67-3.12 particlescm-1 in Tridacnidae, Trochidae and fish intestines. Further analysis revealed that the characteristics of microplastics in the organisms were different from those in the environment, indicating preferential enrichment in the organisms. Furthermore, there was an obvious correlation between microplastic concentration and symbiotic density in corals. Furthermore, caspase3 activity was significantly positively correlated with the microplastic content in the small-polyp coral Pocillopora damicornis, but the large-polyp coral Galaxea fascicularis showed higher tolerance to microplastics. Taken together, our results suggest that microplastics are selectively enriched in corals and other reef-dwellers, in which they exact differential stress (apoptotic) effects, with the potential to impact the coral-Symbiodiniaceae symbiosis and alter the coral community structure.

RevDate: 2020-10-21

Stone LBL, MJ Bidochka (2020)

The multifunctional lifestyles of Metarhizium: evolution and applications.

Applied microbiology and biotechnology pii:10.1007/s00253-020-10968-3 [Epub ahead of print].

The genus Metarhizium is comprised of a diverse group of common soil fungi that exhibit multifunctional lifestyles with varying degrees of saprotrophic, endophytic, and insect pathogenic modes of nutrient acquisition. The transcriptome of these species is modulated to reflect immediate needs of the fungus and availability of resources-a form of transcriptional plasticity that allows for physiological adaptation to environments with diverse and dynamic exploitable nutrient sources. In this review, we discuss the endophytic, insect pathogenic lifestyles of Metarhizium spp., including their symbiotic interface, origins, and evolution, and agricultural applications. Isotope labeling experiments have demonstrated that a mutually beneficial exchange of limiting nutrients occurs between the fungus and its host plant, with nitrogen derived via insect pathogenesis being translocated from Metarhizium to host plants in exchange for fixed carbon in the form of photosynthate. Thus, the endophytic and entomopathogenic abilities of Metarhizium spp. are not exclusive of one another, but rather are interdependent and reciprocal in nature. Although endophytic, insect pathogenic fungi (EIPF) could certainly have evolved from insect pathogenic fungi, phylogenomic evidence indicates that this genus is more closely related to plant-associated fungi than animal pathogens, suggesting that Metarhizium evolved from a lineage of plant symbionts, which subsequently acquired genes for insect pathogenesis. Entomopathogenicity may have been an adaptive trait, allowing for procurement of insect-derived nitrogen that could be translocated to host plants and bartered for fixed carbon, thereby improving the stability of fungal-plant symbioses. Given their ability to simultaneously parasitize soil insects, including a number of pests of agriculturally important crops, as well as promote plant health, growth, and productivity, Metarhizium spp. are considered promising alternatives to the chemical pesticides and fertilizers that have wreaked havoc on the health and integrity of ecosystems. KEY POINTS: • Metarhizium is a fungus that is an insect pathogen as well as a plant symbiont. • The genus Metarhizium has specialist and generalist insect pathogens. • Metarhizium is phylogenetically most closely related to plant endophytes.

RevDate: 2020-10-21

Pyle AE, Johnson AM, TA Villareal (2020)

Isolation, growth, and nitrogen fixation rates of the Hemiaulus-Richelia (diatom-cyanobacterium) symbiosis in culture.

PeerJ, 8:e10115 pii:10115.

Nitrogen fixers (diazotrophs) are often an important nitrogen source to phytoplankton nutrient budgets in N-limited marine environments. Diazotrophic symbioses between cyanobacteria and diatoms can dominate nitrogen-fixation regionally, particularly in major river plumes and in open ocean mesoscale blooms. This study reports the successful isolation and growth in monocultures of multiple strains of a diatom-cyanobacteria symbiosis from the Gulf of Mexico using a modified artificial seawater medium. We document the influence of light and nutrients on nitrogen fixation and growth rates of the host diatom Hemiaulus hauckii Grunow together with its diazotrophic endosymbiont Richelia intracellularis Schmidt, as well as less complete results on the Hemiaulus membranaceus-R. intracellularis symbiosis. The symbioses rates reported here are for the joint diatom-cyanobacteria unit. Symbiont diazotrophy was sufficient to support both the host diatom and cyanobacteria symbionts, and the entire symbiosis replicated and grew without added nitrogen. Maximum growth rates of multiple strains of H. hauckii symbioses in N-free medium with N2 as the sole N source were 0.74-0.93 div d-1. Growth rates followed light saturation kinetics in H. hauckii symbioses with a growth compensation light intensity (EC) of 7-16 µmol m-2s-1and saturation light level (EK) of 84-110 µmol m-2s-1. Nitrogen fixation rates by the symbiont while within the host followed a diel pattern where rates increased from near-zero in the scotophase to a maximum 4-6 h into the photophase. At the onset of the scotophase, nitrogen-fixation rates declined over several hours to near-zero values. Nitrogen fixation also exhibited light saturation kinetics. Maximum N2 fixation rates (84 fmol N2 heterocyst-1h-1) in low light adapted cultures (50 µmol m-2s-1) were approximately 40-50% of rates (144-154 fmol N2 heterocyst-1h-1) in high light (150 and 200 µmol m-2s-1) adapted cultures. Maximum laboratory N2 fixation rates were ~6 to 8-fold higher than literature-derived field rates of the H. hauckii symbiosis. In contrast to published results on the Rhizosolenia-Richelia symbiosis, the H. hauckii symbiosis did not use nitrate when added, although ammonium was consumed by the H. hauckii symbiosis. Symbiont-free host cell cultures could not be established; however, a symbiont-free H. hauckii strain was isolated directly from the field and grown on a nitrate-based medium that would not support DDA growth. Our observations together with literature reports raise the possibility that the asymbiotic H. hauckii are lines distinct from an obligately symbiotic H. hauckii line. While brief descriptions of successful culture isolation have been published, this report provides the first detailed description of the approaches, handling, and methodologies used for successful culture of this marine symbiosis. These techniques should permit a more widespread laboratory availability of these important marine symbioses.

RevDate: 2020-10-21

Khakisahneh S, Zhang XY, Nouri Z, et al (2020)

Gut Microbiota and Host Thermoregulation in Response to Ambient Temperature Fluctuations.

mSystems, 5(5):.

Ambient temperature (Ta) is an important factor in shaping phenotypic plasticity. Plasticity is generally beneficial for animals in adapting to their environments. Gut microbiota are crucial in regulating host physiological and behavioral processes. However, whether the gut microbiota play a role in regulating host phenotypic plasticity under the conditions of repeated fluctuations in environmental factors has rarely been examined. We used intermittent Ta acclimations to test the hypothesis that the plasticity of gut microbiota confers on the host a metabolic adaptation to Ta fluctuations. Mongolian gerbils (Meriones unguiculatus) were acclimated to intermittent 5°C to 23°C, 37°C to 23°C or 23°C to 23°C conditions for 3 cycles (totally 3 months). Intermittent Ta acclimations induced variations in resting metabolic rate (RMR), serum thyroid hormones, and core body temperature (Tb). We further identified that the β-diversity of the microbial community varied with Ta and showed diverse responses during the 3 cycles. Some specific bacteria were more sensitive to Ta and were associated with host dynamic metabolic plasticity during Ta acclimations. In addition, depletion of gut microbiota in antibiotic-treated gerbils impaired metabolic plasticity, particularly at low Ta , whereas supplementation with propionate as an energy resource improved the inhibited thermogenic capacity and increased the survival rate in the cold. These findings demonstrate that both gut microbiota and their host were more adaptive after repeated acclimations, and dynamic gut microbiota and their metabolites may confer host plasticity in thermoregulation in response to Ta fluctuations. It also implies that low Ta is a crucial cue in driving symbiosis between mammals and their gut microbiota during evolution.IMPORTANCE Whether gut microbiota play a role in regulating host phenotypic plasticity in small mammals living in seasonal environments has rarely been examined. The present study, through an intermittent temperature acclimation model, indicates that both gut microbiota and their host were more adaptive after repeated acclimations. It also demonstrates that dynamic gut microbiota confer host plasticity in thermoregulation in response to intermittent temperature fluctuations. Furthermore, low temperature seems to be a crucial cue in driving the symbiosis between mammals and their gut microbiota during evolution.

RevDate: 2020-10-21

Duplouy A, Pranter R, Warren-Gash H, et al (2020)

Towards unravelling Wolbachia global exchange: a contribution from the Bicyclus and Mylothris butterflies in the Afrotropics.

BMC microbiology, 20(1):319 pii:10.1186/s12866-020-02011-2.

BACKGROUND: Phylogenetically closely related strains of maternally inherited endosymbiotic bacteria are often found in phylogenetically divergent, and geographically distant insect host species. The interspecies transfer of the symbiont Wolbachia has been thought to have occurred repeatedly, facilitating its observed global pandemic. Few ecological interactions have been proposed as potential routes for the horizontal transfer of Wolbachia within natural insect communities. These routes are however likely to act only at the local scale, but how they may support the global distribution of some Wolbachia strains remains unclear.

RESULTS: Here, we characterize the Wolbachia diversity in butterflies from the tropical forest regions of central Africa to discuss transfer at both local and global scales. We show that numerous species from both the Mylothris (family Pieridae) and Bicyclus (family Nymphalidae) butterfly genera are infected with similar Wolbachia strains, despite only minor interclade contacts across the life cycles of the species within their partially overlapping ecological niches. The phylogenetic distance and differences in resource use between these genera rule out the role of ancestry, hybridization, and shared host-plants in the interspecies transfer of the symbiont. Furthermore, we could not identify any shared ecological factors to explain the presence of the strains in other arthropod species from other habitats, or even ecoregions.

CONCLUSION: Only the systematic surveys of the Wolbachia strains from entire species communities may offer the material currently lacking for understanding how Wolbachia may transfer between highly different and unrelated hosts, as well as across environmental scales.

RevDate: 2020-10-21
CmpDate: 2020-10-21

Huang H, Ren L, Li H, et al (2020)

The nesting preference of an invasive ant is associated with the cues produced by actinobacteria in soil.

PLoS pathogens, 16(9):e1008800.

Soil-dwelling animals are at risk of pathogen infection in soils. When choosing nesting sites, animals could reduce this risk by avoiding contact with pathogens, yet there is currently little evidence. We tested this hypothesis using Solenopsis invicta as a model system. Newly mated queens of S. invicta were found to nest preferentially in soil containing more actinobacteria of Streptomyces and Nocardiopsis and to be attracted to two volatiles produced by these bacteria, geosmin and 2-methylisoborneol. Actinobacteria-rich soil was favored by S. invicta and this soil contained fewer putative entomopathogenic fungi than adjacent areas. Queens in such soil benefited from a higher survival rate. In culture, isolated actinobacteria inhibited entomopathogenic fungi, suggested that their presence may reduce the risk of fungal infection. These results indicated a soil-dwelling ant may choose nest sites presenting relatively low pathogen risk by detecting the odors produced by bacteria with anti-fungal properties.

RevDate: 2020-10-21
CmpDate: 2020-10-21

Mehta AP, Ko Y, Supekova L, et al (2019)

Toward a Synthetic Yeast Endosymbiont with a Minimal Genome.

Journal of the American Chemical Society, 141(35):13799-13802.

Based on the endosymbiotic theory, one of the key events that occurred during mitochondrial evolution was an extensive loss of nonessential genes from the protomitochondrial endosymbiont genome and transfer of some of the essential endosymbiont genes to the host nucleus. We have developed an approach to recapitulate various aspects of endosymbiont genome minimization using a synthetic system consisting of Escherichia coli endosymbionts within host yeast cells. As a first step, we identified a number of E. coli auxotrophs of central metabolites that can form viable endosymbionts within yeast cells. These studies provide a platform to identify nonessential biosynthetic pathways that can be deleted in the E. coli endosymbionts to investigate the evolutionary adaptations in the host and endosymbiont during the evolution of mitochondria.

RevDate: 2020-10-21
CmpDate: 2020-10-21

Villasante A, Ramírez C, Rodríguez H, et al (2019)

In-depth analysis of swim bladder-associated microbiota in rainbow trout (Oncorhynchus mykiss).

Scientific reports, 9(1):8974 pii:10.1038/s41598-019-45451-1.

Our knowledge regarding microbiota associated with the swim bladder of physostomous, fish with the swim bladder connected to the esophagus via the pneumatic duct, remains largely unknown. The goal of this study was to conduct the first in-depth characterization of the swim bladder-associated microbiota using high-throughput sequencing of the V4 region of the 16 S rRNA gene in rainbow trout (Oncorhynchus mykiss). We observed major differences in bacterial communities composition between swim bladder-associated microbiota and distal intestine digesta microbiota in fish. Whilst bacteria genera, such as Cohnella, Lactococcus and Mycoplasma were more abundant in swim bladder-associated microbiota, Citrobacter, Rhodobacter and Clavibacter were more abundant in distal intestine digesta microbiota. The presumptive metabolic function analysis (PICRUSt) revealed several metabolic pathways to be more abundant in the swim bladder-associated microbiota, including metabolism of carbohydrates, nucleotides and lipoic acid as well as oxidative phosphorylation, cell growth, translation, replication and repair. Distal intestine digesta microbiota showed greater abundance of nitrogen metabolism, amino acid metabolism, biosynthesis of unsaturated fatty acids and bacterial secretion system. We demonstrated swim bladder harbors a unique microbiota, which composition and metabolic function differ from microbiota associated with the gut in fish.

RevDate: 2020-10-20

Dal Forno M, Lawrey JD, Sikaroodi M, et al (2020)

Extensive photobiont sharing in a rapidly-radiating cyanolichen clade.

Molecular ecology [Epub ahead of print].

Recent studies have uncovered remarkable diversity Dictyonema basidiolichens, here recognized as subtribe Dictyonemateae. This group includes five genera and 148 species, but hundreds more await description. The photobionts of these lichens belong to Rhizonema, a recently resurrected cyanobacterial genus known by a single species. To further investigate photobiont diversity within Dictyonemateae, we generated 765 new cyanobacterial sequences from 635 specimens collected from 18 countries. The ITS barcoding locus supported the recognition of 200 mycobiont (fungal) species among these samples, but the photobiont diversity was comparatively low. Our analyses revealed three main divisions of Rhizonema, with two repeatedly recovered as monophyletic (proposed as new species), and the third mostly paraphyletic. The paraphyletic lineage corresponds to R. interruptum and partnered with mycobionts from all five genera in Dictyonemateae. There was no evidence of photobiont-mycobiont co-speciation, but one of the monophyletic lineages of Rhizonema appears to partner predominantly with one of the two major clades of Cora (mycobiont) with samples collected largely from the northern Andes. Molecular clock estimations indicate the Rhizonema species are much older than the fungal species in the Dictyonemateae, suggesting that these basidiolichens obtained their photobionts from older ascolichen lineages and the photobiont variation in extant lineages of Dictyonemateae is the result of multiple photobiont switches. These results support the hypothesis of lichens representing "fungal farmers", in which diverse mycobiont lineages associate with a substantially lower diversity of photobionts by sharing those photobionts best suited for the lichen symbiosis among multiple and often unrelated mycobiont lineages.

RevDate: 2020-10-20

Ori F, Leonardi M, Faccio A, et al (2020)

Synthesis and ultrastructural observation of arbutoid mycorrhizae of black truffles (Tuber melanosporum and T. aestivum).

Mycorrhiza pii:10.1007/s00572-020-00985-5 [Epub ahead of print].

Arbutus unedo (the strawberry tree) is a Mediterranean shrub which forms arbutoid mycorrhizae with a variety of Asco- and Basidiomycetes. After the discovery of the mycorrhizal symbiosis between A. unedo and Tuber borchii, in this study, arbutoid mycorrhizae were synthetized in greenhouse with Tuber aestivum and Tuber melanosporum. Six months after inoculation, both species colonized the roots of all inoculated A. unedo seedlings, but mature mycorrhizae were only observed after 12 months. Ultrastructure analysis of Tuber arbutoid mycorrhizae was described for the first time, showing, as observed in typical endosymbiosis, a rearrangement of host cells and the creation of an interface compartment with both truffle species. Immunolabelling experiments suggested that pectins are not present in the interface matrix surrounding the intracellular hyphae. Thus, the ability to establish symbiosis with A. unedo seems to be a common feature in the genus Tuber, opening up the possibility to use this plant for mycorrhization with valuable truffles. This could represent an important economic opportunity in Mediterranean areas by combining the production of truffles, edible fruits and valued honey.

RevDate: 2020-10-19

van Capelleveen G, Amrit C, Zijm H, et al (2020)

Toward building recommender systems for the circular economy: Exploring the perils of the European Waste Catalogue.

Journal of environmental management, 277:111430 pii:S0301-4797(20)31355-4 [Epub ahead of print].

The growth in the number of industries aiming at more sustainable business processes is driving the use of the European Waste Catalogue (EWC). For example, the identification of industrial symbiosis opportunities, in which a user-generated item description has to be annotated with exactly one EWC tag from an a priori defined tag ontology. This study aims to help researchers understand the perils of the EWC when building a recommender system based on natural language processing techniques. We experiment with semantic enhancement (an EWC thesaurus) and the linguistic contexts of words (learned by Word2vec) for detecting term vector similarity in addition to direct term matching algorithms, which often fail to detect an identical term in the short text generated by users. Our in-depth analysis provides an insight into why the different recommenders were unable to generate a correct annotation and motivates a discussion on the current design of the EWC system.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Schneider SA, JS Lapolla (2020)

Trophobiosis between a new species of Williamsrhizoecus (Hemiptera: Coccomorpha: Rhizoecidae) and Acropyga silvestrii (Hymenoptera: Formicidae) in Tanzania.

Zootaxa, 4853(2):zootaxa.4853.2.9 pii:zootaxa.4853.2.9.

A new myrmecophilous species of root mealybug, Williamsrhizoecus udzungwensis sp. n., is described from individuals found living within a nest of Acropyga silvestrii in the Udzungwa Mountains of Tanzania. Acropyga ants are highly specialized, obligate associates of scale insects, typically members of the scale family Xenococcidae. Acropyga are best known for vertically transmitting trophobiotic partners during their nuptial flights and for housing them within brood chambers. This article presents the first record of trophobiosis between a species of Williamsrhizoecus and Acropyga, and only the second record of an association between Acropyga and rhizoecids in the Old World. This discovery contributes important information about the few species of Rhizoecidae confirmed to engage in these unique symbioses, each putatively the result of a past horizontal transmission event from a xenococcid to a rhizoecid lineage. Included is a discussion on the diagnosis of Williamsrhizoecus and an updated key to the species.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Ashour DS, AA Othman (2020)

Parasite-bacteria interrelationship.

Parasitology research, 119(10):3145-3164.

Parasites and bacteria have co-evolved with humankind, and they interact all the time in a myriad of ways. For example, some bacterial infections result from parasite-dwelling bacteria as in the case of Salmonella infection during schistosomiasis. Other bacteria synergize with parasites in the evolution of human disease as in the case of the interplay between Wolbachia endosymbiont bacteria and filarial nematodes as well as the interaction between Gram-negative bacteria and Schistosoma haematobium in the pathogenesis of urinary bladder cancer. Moreover, secondary bacterial infections may complicate several parasitic diseases such as visceral leishmaniasis and malaria, due to immunosuppression of the host during parasitic infections. Also, bacteria may colonize the parasitic lesions; for example, hydatid cysts and skin lesions of ectoparasites. Remarkably, some parasitic helminths and arthropods exhibit antibacterial activity usually by the release of specific antimicrobial products. Lastly, some parasite-bacteria interactions are induced as when using probiotic bacteria to modulate the outcome of a variety of parasitic infections. In sum, parasite-bacteria interactions involve intricate processes that never cease to intrigue the researchers. However, understanding and exploiting these interactions could have prophylactic and curative potential for infections by both types of pathogens.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Vidal LMR, Venas TM, Gonçalves ARP, et al (2020)

Rapid screening of marine bacterial symbionts using MALDI-TOF MS.

Archives of microbiology, 202(8):2329-2336.

Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) is a rapid, cost-effective and high-throughput method for bacteria characterization. However, most previous studies focused on clinical isolates. In this study, we evaluated the use of MALDI-TOF MS as a rapid screening tool for marine bacterial symbionts. A set of 255 isolates from different marine sources (corals, sponge, fish and seawater) was analyzed using cell lysates to obtain a rapid grouping. Cluster analysis of mass spectra and 16S rRNA showed 18 groups, including Vibrio, Bacillus, Pseudovibrio, Alteromonas and Ruegeria. MALDI-TOF distance similarity scores ≥ 60% and ≥ 70% correspond to ≥ 98.7% 16S rRNA gene sequence similarity and ≥ 95% pyrH gene sequence similarity, respectively. MALDI-TOF MS is a useful tool for Vibrio species groups' identification.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Hall AR, Ashby B, Bascompte J, et al (2020)

Measuring Coevolutionary Dynamics in Species-Rich Communities.

Trends in ecology & evolution, 35(6):539-550.

Identifying different types of coevolutionary dynamics is important for understanding biodiversity and infectious disease. Past work has often focused on pairs of interacting species, but observations of extant communities suggest that coevolution in nature occurs in networks of antagonism and mutualism. We discuss challenges for measuring coevolutionary dynamics in species-rich communities, and we suggest ways that established approaches used for two-species interactions can be applied. We propose ways that such data can be complemented by genomic information and linked back to extant communities via network structure, and we suggest avenues for new theoretical work to strengthen these connections. Quantifying coevolution in species-rich communities has several potential benefits, such as identifying coevolutionary units within networks and uncovering coevolutionary interactions among pathogens of humans, livestock, and crops.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Song C, Von Ahn S, Rohr RP, et al (2020)

Towards a Probabilistic Understanding About the Context-Dependency of Species Interactions.

Trends in ecology & evolution, 35(5):384-396.

Observational and experimental studies have shown that an interaction class between two species (be it mutualistic, competitive, antagonistic, or neutral) may switch to a different class, depending on the biotic and abiotic factors within which species are observed. This complexity arising from the evidence of context-dependencies has underscored a difficulty in establishing a systematic analysis about the extent to which species interactions are expected to switch in nature and experiments. Here, we propose an overarching theoretical framework, by integrating probabilistic and structural approaches, to establish null expectations about switches of interaction classes across environmental contexts. This integration provides a systematic platform upon which it is possible to establish new hypotheses, clear predictions, and quantifiable expectations about the context-dependency of species interactions.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Caruso R, Lo BC, G Núñez (2020)

Host-microbiota interactions in inflammatory bowel disease.

Nature reviews. Immunology, 20(7):411-426.

The mammalian intestine is colonized by trillions of microorganisms that have co-evolved with the host in a symbiotic relationship. The presence of large numbers of symbionts near the epithelial surface of the intestine poses an enormous challenge to the host because it must avoid the activation of harmful inflammatory responses to the microorganisms while preserving its ability to mount robust immune responses to invading pathogens. In patients with inflammatory bowel disease, there is a breakdown of the multiple strategies that the immune system has evolved to promote the separation between symbiotic microorganisms and the intestinal epithelium and the effective killing of penetrant microorganisms, while suppressing the activation of inappropriate T cell responses to resident microorganisms. Understanding the complex interactions between intestinal microorganisms and the host may provide crucial insight into the pathogenesis of inflammatory bowel disease as well as new avenues to prevent and treat the disease.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Fast D, Petkau K, Ferguson M, et al (2020)

Vibrio cholerae-Symbiont Interactions Inhibit Intestinal Repair in Drosophila.

Cell reports, 30(4):1088-1100.e5.

Pathogen-mediated damage to the intestinal epithelium activates compensatory growth and differentiation repair programs in progenitor cells. Accelerated progenitor growth replenishes damaged tissue and maintains barrier integrity. Despite the importance of epithelial renewal to intestinal homeostasis, we know little about the effects of pathogen-commensal interactions on progenitor growth. We find that the enteric pathogen Vibrio cholerae blocks critical growth and differentiation pathways in Drosophila progenitors, despite extensive damage to epithelial tissue. We show that the inhibition of epithelial repair requires interactions between the Vibrio cholerae type six secretion system and a community of common symbiotic bacteria, as elimination of the gut microbiome is sufficient to restore homeostatic growth in infected intestines. This work highlights the importance of pathogen-symbiont interactions for intestinal immune responses and outlines the impact of the type six secretion system on pathogenesis.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Ke F, You S, Huang S, et al (2019)

Herbivore range expansion triggers adaptation in a subsequently-associated third trophic level species and shared microbial symbionts.

Scientific reports, 9(1):10314 pii:10.1038/s41598-019-46742-3.

Invasive species may change the life history strategies, distribution, genetic configuration and trophic interactions of native species. The diamondback moth, Plutella xylostella L., is an invasive herbivore attacking cultivated and wild brassica plants worldwide. Here we present phylogeographic analyses of P. xylostella and one of its major parasitoids, Cotesia vestalis, using mitochondrial markers, revealing the genetic diversity and evolutionary history of these two species. We find evidence that C. vestalis originated in Southwest China, then adapted to P. xylostella as a new host by ecological sorting as P. xylostella expanded its geographic range into this region. Associated with the expansion of P. xylostella, Wolbachia symbionts were introduced into local populations of the parasitoid through horizontal transfer from its newly associated host. Insights into the evolutionary history and phylogeographic system of the herbivore and its parasitoid provide an important basis for better understanding the impacts of biological invasion on genetic configuration of local species.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Hoadley KD, Lewis AM, Wham DC, et al (2019)

Host-symbiont combinations dictate the photo-physiological response of reef-building corals to thermal stress.

Scientific reports, 9(1):9985 pii:10.1038/s41598-019-46412-4.

High sea surface temperatures often lead to coral bleaching wherein reef-building corals lose significant numbers of their endosymbiotic dinoflagellates (Symbiodiniaceae). These increasingly frequent bleaching events often result in large scale coral mortality, thereby devasting reef systems throughout the world. The reef habitats surrounding Palau are ideal for investigating coral responses to climate perturbation, where many inshore bays are subject to higher water temperature as compared with offshore barrier reefs. We examined fourteen physiological traits in response to high temperature across various symbiotic dinoflagellates in four common Pacific coral species, Acropora muricata, Coelastrea aspera, Cyphastrea chalcidicum and Pachyseris rugosa found in both offshore and inshore habitats. Inshore corals were dominated by a single homogenous population of the stress tolerant symbiont Durusdinium trenchii, yet symbiont thermal response and physiology differed significantly across coral species. In contrast, offshore corals harbored specific species of Cladocopium spp. (ITS2 rDNA type-C) yet all experienced similar patterns of photoinactivation and symbiont loss when heated. Additionally, cell volume and light absorption properties increased in heated Cladocopium spp., leading to a greater loss in photo-regulation. While inshore coral temperature response was consistently muted relative to their offshore counterparts, high physiological variability in D. trenchii across inshore corals suggests that bleaching resilience among even the most stress tolerant symbionts is still heavily influenced by their host environment.

RevDate: 2020-10-20
CmpDate: 2020-10-20

Di Salvo M, Calcagnile M, Talà A, et al (2019)

The Microbiome of the Maculinea-Myrmica Host-Parasite Interaction.

Scientific reports, 9(1):8048 pii:10.1038/s41598-019-44514-7.

Maculinea (=Phengaris) are endangered butterflies that are characterized by a very complex biological cycle. Maculinea larvae behave as obligate parasites whose survival is strictly dependent on both particular food plants and species-specific Myrmica ants. In this interaction, Maculinea caterpillars induce Myrmica workers to retrieve and rear them in the nest by chemical and acoustic deception. Social insect symbiotic microorganisms play a key role in intraspecific and interspecific communication; therefore, it is possible that the Maculinea caterpillar microbiome might be involved in the chemical cross-talk by producing deceptive semiochemicals for host ants. To address this point, the microbiota of Maculinea alcon at different larval stages (phytophagous early larvae, intermediate larvae, carnivorous late larvae) was analyzed by using 16S rRNA-guided metabarcoding approach and compared to that of the host ant Myrmica scabrinodis. Structural and deduced functional profiles of the microbial communities were recorded, which were used to identify specific groups of microorganisms that may be involved in the chemical cross-talk. One of the most notable features was the presence in all larval stages and in the ants of two bacteria, Serratia marcescens and S. entomophila, which are involved in the chemical cross-talk between the microbes and their hosts.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Rouzé H, Lecellier G, Pochon X, et al (2019)

Unique quantitative Symbiodiniaceae signature of coral colonies revealed through spatio-temporal survey in Moorea.

Scientific reports, 9(1):7921 pii:10.1038/s41598-019-44017-5.

One of the mechanisms of rapid adaptation or acclimatization to environmental changes in corals is through the dynamics of the composition of their associated endosymbiotic Symbiodiniaceae community. The various species of these dinoflagellates are characterized by different biological properties, some of which can confer stress tolerance to the coral host. Compelling evidence indicates that the corals' Symbiodiniaceae community can change via shuffling and/or switching but the ecological relevance and the governance of these processes remain elusive. Using a qPCR approach to follow the dynamics of Symbiodiniaceae genera in tagged colonies of three coral species over a 10-18 month period, we detected putative genus-level switching of algal symbionts, with coral species-specific rates of occurrence. However, the dynamics of the corals' Symbiodiniaceae community composition was not driven by environmental parameters. On the contrary, putative shuffling event were observed in two coral species during anomalous seawater temperatures and nutrient concentrations. Most notably, our results reveal that a suit of permanent Symbiodiniaceae genera is maintained in each colony in a specific range of quantities, giving a unique 'Symbiodiniaceae signature' to the host. This individual signature, together with sporadic symbiont switching may account for the intra-specific differences in resistance and resilience observed during environmental anomalies.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Zabel B, Yde CC, Roos P, et al (2019)

Novel Genes and Metabolite Trends in Bifidobacterium longum subsp. infantis Bi-26 Metabolism of Human Milk Oligosaccharide 2'-fucosyllactose.

Scientific reports, 9(1):7983 pii:10.1038/s41598-019-43780-9.

Human milk oligosaccharides (HMOs) function as prebiotics for beneficial bacteria in the developing gut, often dominated by Bifidobacterium spp. To understand the relationship between bifidobacteria utilizing HMOs and how the metabolites that are produced could affect the host, we analyzed the metabolism of HMO 2'-fucosyllactose (2'-FL) in Bifidobacterium longum subsp. infantis Bi-26. RNA-seq and metabolite analysis (NMR/GCMS) was performed on samples at early (A600 = 0.25), mid-log (0.5-0.7) and late-log phases (1.0-2.0) of growth. Transcriptomic analysis revealed many gene clusters including three novel ABC-type sugar transport clusters to be upregulated in Bi-26 involved in processing of 2'-FL along with metabolism of its monomers glucose, fucose and galactose. Metabolite data confirmed the production of formate, acetate, 1,2-propanediol, lactate and cleaving of fucose from 2'-FL. The formation of acetate, formate, and lactate showed how the cell uses metabolites during fermentation to produce higher levels of ATP (mid-log compared to other stages) or generate cofactors to balance redox. We concluded that 2'-FL metabolism is a complex process involving multiple gene clusters, that produce a more diverse metabolite profile compared to lactose. These results provide valuable insight on the mode-of-action of 2'-FL utilization by Bifidobacterium longum subsp. infantis Bi-26.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Wang HL, Lei T, Xia WQ, et al (2019)

Insight into the microbial world of Bemisia tabaci cryptic species complex and its relationships with its host.

Scientific reports, 9(1):6568 pii:10.1038/s41598-019-42793-8.

The 37 currently recognized Bemisia tabaci cryptic species are economically important species and contain both primary and secondary endosymbionts, but their diversity has never been mapped systematically across the group. To achieve this, PacBio sequencing of full-length bacterial 16S rRNA gene amplicons was carried out on 21 globally collected species in the B. tabaci complex, and two samples from B. afer were used here as outgroups. The microbial diversity was first explored across the major lineages of the whole group and 15 new putative bacterial sequences were observed. Extensive comparison of our results with previous endosymbiont diversity surveys which used PCR or multiplex 454 pyrosequencing platforms showed that the bacterial diversity was underestimated. To validate these new putative bacteria, one of them (Halomonas) was first confirmed to be present in MED B. tabaci using Hiseq2500 and FISH technologies. These results confirmed PacBio is a reliable and informative venue to reveal the bacterial diversity of insects. In addition, many new secondary endosymbiotic strains of Rickettsia and Arsenophonus were found, increasing the known diversity in these groups. For the previously described primary endosymbionts, one Portiera Operational Taxonomic Units (OTU) was shared by all B. tabaci species. The congruence of the B. tabaci-host and Portiera phylogenetic trees provides strong support for the hypothesis that primary endosymbionts co-speciated with their hosts. Likewise, a comparison of bacterial alpha diversities, Principal Coordinate Analysis, indistinct endosymbiotic communities harbored by different species and the co-divergence analyses suggest a lack of association between overall microbial diversity with cryptic species, further indicate that the secondary endosymbiont-mediated speciation is unlikely to have occurred in the B. tabaci species group.

RevDate: 2020-10-19
CmpDate: 2020-10-19

Wang L, Ren L, Li C, et al (2019)

Effects of endophytic fungi diversity in different coniferous species on the colonization of Sirex noctilio (Hymenoptera: Siricidae).

Scientific reports, 9(1):5077 pii:10.1038/s41598-019-41419-3.

Diversity of endophyte communities of the host tree affects the oviposition behavior of Sirex noctilio and the growth of its symbiotic fungus Amylostereum areolatum. In this study, we evaluated the structure and distribution of endophyte communities in the host tree (Pinus sylvestris var. mongolica) of S. noctilio and eight potential host tree species in China. Overall, 1626 fungal strains were identified by using internal transcribed spacer sequencing and morphological features. Each tree species harbored a fungal endophyte community with a unique structure, with the genus Trichoderma common to different communities. The isolation and colonization rate of endophytes from Pinus tabulaeformis, followed by P. sylvestris var. mongolica, were lower than those of other species. The proportion of endophytic fungi that strongly inhibited S. noctilio and symbiotic fungus growth was significantly lower in P. tabulaeformis, P. sylvestris var. mongolica and P. yunnanensis. Further, the diversity of the endophyte communities appeared to be predominantly influenced by tree species and the region, and, to a lesser extent, by the trunk height. Collectively, the data indicated that P. tabulaeformis might be at a higher risk of invasion and colonization by S. noctilio than other trees.

RevDate: 2020-10-20
CmpDate: 2020-10-20

Landler L, Skelton J, Painter MS, et al (2019)

Ectosymbionts alter spontaneous responses to the Earth's magnetic field in a crustacean.

Scientific reports, 9(1):3105.

Magnetic sensing is used to structure every-day, non-migratory behaviours in many animals. We show that crayfish exhibit robust spontaneous magnetic alignment responses. These magnetic behaviours are altered by interactions with Branchiobdellidan worms, which are obligate ectosymbionts. Branchiobdellidan worms have previously been shown to have positive effects on host growth when present at moderate densities, and negative effects at relatively high densities. Here we show that crayfish with moderate densities of symbionts aligned bimodally along the magnetic northeast-southwest axis, similar to passive magnetic alignment responses observed across a range of stationary vertebrates. In contrast, crayfish with high symbiont densities failed to exhibit consistent alignment relative to the magnetic field. Crayfish without symbionts shifted exhibited quadramodal magnetic alignment and were more active. These behavioural changes suggest a change in the organization of spatial behaviour with increasing ectosymbiont densities. We propose that the increased activity and a switch to quadramodal magnetic alignment may be associated with the use of systematic search strategies. Such a strategy could increase contact-rates with conspecifics in order to replenish the beneficial ectosymbionts that only disperse between hosts during direct contact. Our results demonstrate that crayfish perceive and respond to magnetic fields, and that symbionts influence magnetically structured spatial behaviour of their hosts.

RevDate: 2020-10-19

Guo DJ, Singh RK, Singh P, et al (2020)

Complete Genome Sequence of Enterobacter roggenkampii ED5, a Nitrogen Fixing Plant Growth Promoting Endophytic Bacterium With Biocontrol and Stress Tolerance Properties, Isolated From Sugarcane Root.

Frontiers in microbiology, 11:580081.

Sugarcane is the leading economic crop in China, requires huge quantities of nitrogen in the preliminary plant growth stages. However, the use of an enormous amount of nitrogen fertilizer increases the production price, and have detrimental results on the environment, causes severe soil and water pollution. In this study, a total of 175 endophytic strains were obtained from the sugarcane roots, belonging to five different species, i.e., Saccharum officinarum, Saccharum barberi, Saccharum robustum, Saccharum spontaneum, and Saccharum sinense. Among these, only 23 Enterobacter strains were chosen based on nitrogen fixation, PGP traits, hydrolytic enzymes production, and antifungal activities. Also, all selected strains were showed diverse growth range under different stress conditions, i.e., pH (5-10), temperature (20-45°C), and NaCl (7-12%) and 14 strains confirmed positive nifH, and 12 strains for acdS gene amplification, suggested that these strains could fix nitrogen along with stress tolerance properties. Out of 23 selected strains, Enterobacter roggenkampii ED5 was the most potent strain. Hence, this strain was further selected for comprehensive genome analysis, which includes a genome size of 4,702,851 bp and 56.05% of the average G + C content. Genome annotations estimated 4349 protein-coding with 83 tRNA and 25 rRNA genes. The CDSs number allocated to the KEGG, COG, and GO database were 2839, 4028, and 2949. We recognized a total set of genes that are possibly concerned with ACC deaminase activity, siderophores and plant hormones production, nitrogen and phosphate metabolism, symbiosis, root colonization, biofilm formation, sulfur assimilation and metabolism, along with resistance response toward a range of biotic and abiotic stresses. E. roggenkampii ED5 strain was also a proficient colonizer in sugarcane (variety GT11) and enhanced growth of sugarcane under the greenhouse. To the best of our knowledge, this is the first information on the whole-genome sequence study of endophytic E. roggenkampii ED5 bacterium associated with sugarcane root. And, our findings proposed that identification of predicted genes and metabolic pathways might describe this strain an eco-friendly bioresource to promote sugarcane growth by several mechanisms of actions under multi-stresses.

RevDate: 2020-10-19

Dias T, Pimentel V, Cogo AJD, et al (2020)

The Free-Living Stage Growth Conditions of the Endophytic Fungus Serendipita indica May Regulate Its Potential as Plant Growth Promoting Microbe.

Frontiers in microbiology, 11:562238.

Serendipita indica (former Piriformospora indica) is a non-obligate endophytic fungus and generally a plant growth and defence promoter with high potential to be used in agriculture. However, S. indica may switch from biotrophy to saprotrophy losing its plant growth promoting traits. Our aim was to understand if the free-living stage growth conditions (namely C availability) regulate S. indica's phenotype, and its potential as plant-growth-promoting-microbe (PGPM). We grew S. indica in its free-living stage under increasing C availabilities (2-20 g L-1 of glucose or sucrose). We first characterised the effect of C availability during free-living stage growth on fungal phenotype: colonies growth and physiology (plasma membrane proton pumps, stable isotopic signatures, and potential extracellular decomposing enzymes). The effect of the C availability during the free-living stage of the PGPM was evaluated on wheat. We observed that C availability during the free-living stage regulated S. indica's growth, ultrastructure and physiology, resulting in two distinct colony phenotypes: compact and explorer. The compact phenotype developed at low C, used peptone as the major C and N source, and displayed higher decomposing potential for C providing substrates; while the explorer phenotype developed at high C, used glucose and sucrose as major C sources and casein and yeast extract as major N sources, and displayed higher decomposing potential for N and P providing substrates. The C availability, or the C/N ratio, during the free-living stage left a legacy to the symbiosis stage, regulating S. indica's potential to promote plant growth: wheat growth promotion by the explorer phenotype was ± 40% higher than that by the compact phenotype. Our study highlights the importance of considering microbial ecology in designing PGPM/biofertilizers. Further studies are needed to test the phenotypes under more extreme conditions, and to understand if the in vitro acquired characteristics persist under field conditions.

RevDate: 2020-10-19

Goulet TL, Erill I, Ascunce MS, et al (2020)

Conceptualization of the Holobiont Paradigm as It Pertains to Corals.

Frontiers in physiology, 11:566968.

Corals' obligate association with unicellular dinoflagellates, family Symbiodiniaceae form the foundation of coral reefs. For nearly a century, researchers have delved into understanding the coral-algal mutualism from multiple levels of resolution and perspectives, and the questions and scope have evolved with each iteration of new techniques. Advances in genetic technologies not only aided in distinguishing between the multitude of Symbiodiniaceae but also illuminated the existence and diversity of other organisms constituting the coral microbiome. The coral therefore is a meta-organism, often referred to as the coral holobiont. In this review, we address the importance of including a holistic perspective to understanding the coral holobiont. We also discuss the ramifications of how different genotypic combinations of the coral consortium affect the holobiont entity. We highlight the paucity of data on most of the coral microbiome. Using Symbiodiniaceae data, we present evidence that the holobiont properties are not necessarily the sum of its parts. We then discuss the consequences of the holobiont attributes to the fitness of the holobiont and the myriad of organisms that contribute to it. Considering the complexity of host-symbiont genotypic combinations will aid in our understanding of coral resilience, robustness, acclimation, and/or adaptation in the face of environmental change and increasing perturbations.

RevDate: 2020-10-18

Creed RP, Skelton J, Farrell KJ, et al (2020)

Strong effects of a mutualism on freshwater community structure.

Ecology [Epub ahead of print].

Numerous mutualisms have been described from terrestrial and marine communities and many of these mutualisms have significant effects on community structure and function. In contrast, there are far fewer examples of mutualisms from freshwater habitats and there is no evidence that any mutualism has community-wide or ecosystem-level consequences. Northern hemisphere crayfish are host to a variety of ectosymbiotic worms called branchiobdellidans. The association between some of these "crayfish worms" and their hosts is a mutualism. The outcome of the association is context dependent and can be influenced by host size, symbiont number and the environment. Here we document in two experiments that the mutualism between crayfish and these worms alters the effect of crayfish on stream community structure and sediment deposition, an important ecosystem variable. We enclosed crayfish stocked with 0 worms, intermediate (3-6) and high worm densities (12) in cages in streams in Boone, NC and Clemson, SC, USA. At both locations, there was a negative relationship between initial worm density and final macroinvertebrate abundance. There was a significant effect of worm treatment on macroinvertebrate community structure in both the Boone and Clemson experiments. In Boone, there were effects on both overall macroinvertebrate abundance and community composition, while in Clemson, changes to community structure were primarily driven by changes in total abundance. There was a negative relationship between benthic sediment volume and initial worm density in both experiments, primarily later in the experiments, though these effects were influenced by sediment deposition rates. Our results are the first to demonstrate strong effects of a mutualism on freshwater communities. Both members of this mutualism are found throughout the northern hemisphere, so similar impacts may occur in many other waterways. Given that various species in addition to crayfish function as keystone species and ecosystem engineers in freshwater systems throughout the world, mutualisms involving these strongly interacting species may be as important to the structure and functioning of freshwater systems as comparable mutualisms in marine and terrestrial systems.

RevDate: 2020-10-18

Skalny AV, Rossi Lima TR, Ke T, et al (2020)

Toxic metal exposure as a possible risk factor for COVID-19 and other respiratory infectious diseases.

Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association pii:S0278-6915(20)30699-2 [Epub ahead of print].

Multiple medical, lifestyle, and environmental conditions, including smoking and particulate pollution, have been considered as risk factors for COronaVIrus Disease 2019 (COVID-19) susceptibility and severity. Taking into account the high level of toxic metals in both particulate matter (PM2.5) and tobacco smoke, the objective of this review is to discuss recent data on the role of heavy metal exposure in development of respiratory dysfunction, immunotoxicity, and severity of viral diseases in epidemiological and experimental studies, as to demonstrate the potential crossroads between heavy metal exposure and COVID-19 severity risk. The existing data demonstrate that As, Cd, Hg, and Pb exposure is associated with respiratory dysfunction and respiratory diseases (COPD, bronchitis). These observations corroborate laboratory findings on the role of heavy metal exposure in impaired mucociliary clearance, reduced barrier function, airway inflammation, oxidative stress, and apoptosis. The association between heavy metal exposure and severity of viral diseases, including influenza and respiratory syncytial virus has been also demonstrated. The latter may be considered a consequence of adverse effects of metal exposure on adaptive immunity. Therefore, reduction of toxic metal exposure may be considered as a potential tool for reducing susceptibility and severity of viral diseases affecting the respiratory system, including COVID-19.

RevDate: 2020-10-19

Rodrigues TF, Bender FR, Sanzovo AWS, et al (2020)

Impact of pesticides in properties of Bradyrhizobium spp. and in the symbiotic performance with soybean.

World journal of microbiology & biotechnology, 36(11):172 pii:10.1007/s11274-020-02949-5.

Soybean [Glycine max (L.) Merr.] has great economic and nutritional importance mainly due to its high protein content. All plant's N needs can be met by the symbiosis with elite Bradyrhizobium strains applied as inoculants to the seeds at sowing time; however, the increasing use of pesticides in seed treatments can impair the contribution of the biological nitrogen fixation. In this study, we report decreases in cell survival of two strains, B. japonicum SEMIA 5079 and B. elkanii SEMIA 587 in seeds inoculated and treated with StandakTop™, composed of the fungicides pyraclostrobin and thiophanate-methyl and the insecticide fipronil, the pesticides most used in soybean seed treatment in several countries. Cell death was enhanced with the time of exposure to the pesticides, and B. elkanii was less tolerant, with almost no detectable viable cells after 15 days. Change in colony morphology with smaller colonies was observed in the presence of the pesticides, being more drastic with the time of exposure, and attributed to an adaptive response towards survival in the presence of the abiotic stress. However, morphological changes were reversible after elimination of the stressing agent and symbiotic performance under controlled greenhouse conditions was similar between strains that had been or not exposed to the pesticides. In addition, no changes in DNA profiles (BOX-PCR) of both strains were observed after the contact with the pesticides. In two field experiments, impacting effects of the pesticides were observed mainly on the total N accumulated in grains of plants relying on both N2-fixation and N-fertilizer. Our data indicate that StandakTop® affects parameters never reported before, including colony morphology of Bradyrhizobium spp. and N metabolism and/or N remobilization to soybean grains.

RevDate: 2020-10-17

Mabaso N, Tinarwo P, N Abbai (2020)

Lack of association between Mycoplasma hominis and Trichomonas vaginalis symbiosis in relation to metronidazole resistance.

Parasitology research pii:10.1007/s00436-020-06930-x [Epub ahead of print].

Resistance mechanisms of Trichomonas vaginalis to metronidazole are still not well understood. It has been shown that Mycoplasma hominis has the ability to establish an endosymbiotic relationship with T. vaginalis. This study investigated the association between T. vaginalis and M. hominis symbiosis in relation to metronidazole resistance. This study included 362 pregnant women from the King Edward VIII hospital in South Africa. The women provided self-collected vaginal swabs for the diagnosis of T. vaginalis by culture. Metronidazole susceptibility using the broth-microdilution assay was performed. Detection of the 16S rRNA from M. hominis using T. vaginalis genomic DNA as the template was performed. All statistical analysis was conducted in R statistical computing software. A total of 21 culture positive isolates were obtained resulting in a prevalence of 5.8% for T. vaginalis in the study population. Under anaerobic incubation, 52.4% (11/21) of the isolates were susceptible to metronidazole (MIC ≤ 1 μg/ml). Intermediate resistance (MIC of 2 μg/ml) and full resistance (4 μg/ml) was observed in 38.1% (8/21) and 9.5% (2/21) of the isolates, respectively. The majority of the isolates 95% (19/20) were susceptible to metronidazole under aerobic conditions. Only one isolate had a MIC of 50 μg/ml. M. hominis was shown to be present in 85.7% (18/21) of the T. vaginalis isolates. However, there was no significant association between metronidazole susceptibility and T. vaginalis-M. hominis symbiosis. This study provides evidence of emerging metronidazole resistance in T. vaginalis. However, these resistance profiles were not associated with M. hominis symbiosis.

RevDate: 2020-10-17

Mens C, Hastwell AH, Su H, et al (2020)

Characterisation of Medicago truncatula CLE34 and CLE35 in nitrate and rhizobia regulation of nodulation.

The New phytologist [Epub ahead of print].

Legumes form a symbiosis with N2 -fixing soil rhizobia, resulting in new root organs called nodules that enable N2 -fixation. Nodulation is a costly process that is tightly regulated by the host through Autoregulation of Nodulation (AON) and nitrate-dependent regulation of nodulation. Both pathways require legume-specific CLAVATA/ESR-related (CLE) peptides. Nitrogen-induced nodulation-suppressing CLE peptides have not previously been investigated in Medicago truncatula, with only rhizobia-induced MtCLE12 and MtCLE13 characterised. Here, we report on novel peptides MtCLE34 and MtCLE35 in nodulation control. The nodulation-suppressing CLE peptides of five legume species were classified into three clades based on sequence homology and phylogeny. This approached identified MtCLE34 and MtCLE35 and four new CLE peptide orthologues of Pisum sativum. Whereas MtCLE12 and MtCLE13 are induced by rhizobia, MtCLE34 and MtCLE35 respond to both rhizobia and nitrate. MtCLE34 was identified as a pseudogene lacking a functional CLE-domain. MtCLE35 was found to inhibit nodulation in a SUNN- and RDN1-dependent manner via overexpression analysis. Together, our findings indicate that MtCLE12 and MtCLE13 have a specific role in AON, while MtCLE35 regulates nodule numbers in response to both rhizobia and nitrate. MtCLE34 likely had a similar role to MtCLE35 but its function was lost due to a premature nonsense mutation.

RevDate: 2020-10-17

Koch EJ, Bongrand C, Bennett BD, et al (2020)

The cytokine MIF controls daily rhythms of symbiont nutrition in an animal-bacterial association.

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

The recent recognition that many symbioses exhibit daily rhythms has encouraged research into the partner dialogue that drives these biological oscillations. Here we characterized the pivotal role of the versatile cytokine macrophage migration inhibitory factor (MIF) in regulating a metabolic rhythm in the model light-organ symbiosis between Euprymna scolopes and Vibrio fischeri As the juvenile host matures, it develops complex daily rhythms characterized by profound changes in the association, from gene expression to behavior. One such rhythm is a diurnal shift in symbiont metabolism triggered by the periodic provision of a specific nutrient by the mature host: each night the symbionts catabolize chitin released from hemocytes (phagocytic immune cells) that traffic into the light-organ crypts, where the population of V. fischeri cells resides. Nocturnal migration of these macrophage-like cells, together with identification of an E. scolopes MIF (EsMIF) in the light-organ transcriptome, led us to ask whether EsMIF might be the gatekeeper controlling the periodic movement of the hemocytes. Western blots, ELISAs, and confocal immunocytochemistry showed EsMIF was at highest abundance in the light organ. Its concentration there was lowest at night, when hemocytes entered the crypts. EsMIF inhibited migration of isolated hemocytes, whereas exported bacterial products, including peptidoglycan derivatives and secreted chitin catabolites, induced migration. These results provide evidence that the nocturnal decrease in EsMIF concentration permits the hemocytes to be drawn into the crypts, delivering chitin. This nutritional function for a cytokine offers the basis for the diurnal rhythms underlying a dynamic symbiotic conversation.

RevDate: 2020-10-19

Murarkar S, Gothankar J, Doke P, et al (2020)

Prevalence and determinants of undernutrition among under-five children residing in urban slums and rural area, Maharashtra, India: a community-based cross-sectional study.

BMC public health, 20(1):1559 pii:10.1186/s12889-020-09642-0.

BACKGROUND: Undernutrition among under five children in India is a major public health problem. Despite India's growth in the economy, the child mortality rate due to undernutrition is still high in both urban and rural areas. Studies that focus on urban slums are scarce. Hence the present study was carried out to assess the prevalence and determinants of undernutrition in children under five in Maharashtra, India.

METHODS: A community-based cross-sectional study was conducted in 16 randomly selected clusters in two districts of Maharashtra state, India. Data were collected through house to house survey by interviewing mothers of under five children. Total 2929 mothers and their 3671 under five children were covered. Multivariate logistic regression analysis was carried out to identify the determinants of child nutritional status seperately in urban and rural areas.

RESULTS: The mean age of the children was 2.38 years (±SD 1.36) and mean age of mothers was 24.25 years (± SD 6.37). Overall prevalence of stunting among children under five was 45.9%, wasting was 17.1 and 35.4% children were underweight. Prevalence of wasting, stunting and underweight were more seen in an urban slum than a rural area. In the rural areas exclusive breast feeding (p < 0.001) and acute diarrhea (p = 0.001) were associated with wasting, children with birth order 2 or less than 2 were associated with stunting and exclusive breast feeding (p < 0.05) and low maternal education were associated with underweight. Whereas in the urban slums exclusive breast feeding (p < 0.05) was associated with wasting, sex of the child (p < 0.05) and type of family (p < 0.05) were associated with stunting,and low income of the family (p < 0.05) was associated with underweight.

CONCLUSIONS: Factors like sex of the child, birth order,exclusive breast feeding,economic status of the family, type of family,acute diarrhea and maternal education have influence on nutritional status of the child. Improvement of maternal education will improve the nutritional status of the child. Strategies are needed to improve the economic status of the community.

TRIAL REGISTRATION: Trial registration number: CTRI/2017/12/010881 ; Registration date:14/12/2017. Retrospectively registered.

RevDate: 2020-10-16

Hoysted GA, Bidartondo MI, Duckett JG, et al (2020)

Phenology and function in lycopod-Mucoromycotina symbiosis.

Lycopods represent a significant diversification point on the land plant phylogenetic tree, being the earliest divergent extant tracheophyte lineage (Kenrick, 1994) and marking the transition from non-vascular to vascular plants. Several lycophytes (Huperzia, Lycopodium, Lycopodiella and Phylloglossum; Supplementary Fig. 1a) possess an "alternation of generations" lifecycle (Kenrick, 1994) which features fully independent gametophyte (haploid) and dominant sporophyte (diploid) generations (Haufler et al, 2016; Supplementary Fig. 1b).

RevDate: 2020-10-19

Pons S, Fournier S, Chervin C, et al (2020)

Phytohormone production by the arbuscular mycorrhizal fungus Rhizophagus irregularis.

PloS one, 15(10):e0240886 pii:PONE-D-20-23648.

Arbuscular mycorrhizal symbiosis is a mutualistic interaction between most land plants and fungi of the glomeromycotina subphylum. The initiation, development and regulation of this symbiosis involve numerous signalling events between and within the symbiotic partners. Among other signals, phytohormones are known to play important roles at various stages of the interaction. During presymbiotic steps, plant roots exude strigolactones which stimulate fungal spore germination and hyphal branching, and promote the initiation of symbiosis. At later stages, different plant hormone classes can act as positive or negative regulators of the interaction. Although the fungus is known to reciprocally emit regulatory signals, its potential contribution to the phytohormonal pool has received little attention, and has so far only been addressed by indirect assays. In this study, using mass spectrometry, we analyzed phytohormones released into the medium by germinated spores of the arbuscular mycorrhizal fungus Rhizophagus irregularis. We detected the presence of a cytokinin (isopentenyl adenosine) and an auxin (indole-acetic acid). In addition, we identified a gibberellin (gibberellin A4) in spore extracts. We also used gas chromatography to show that R. irregularis produces ethylene from methionine and the α-keto γ-methylthio butyric acid pathway. These results highlight the possibility for AM fungi to use phytohormones to interact with their host plants, or to regulate their own development.

RevDate: 2020-10-16

Das M, V Kale (2020)

Extracellular vesicles: Mediators of embryo-maternal crosstalk during pregnancy and a new weapon to fight against infertility.

European journal of cell biology pii:S0171-9335(20)30064-9 [Epub ahead of print].

In modern-day life, infertility is one of the major issues that can affect an individual, both physically and psychologically. Several anatomical, physiological, and genetic factors might contribute to the infertility of an individual. Intercellular communication between trophectoderm and endometrial epithelium triggers successful embryo implantation and thereby establishes pregnancy. Recent studies demonstrate that Extracellular vesicles (EVs) are emerging as one of the crucial components that are involved in embryo-maternal communication and promote pregnancy. Membrane-bound EVs release several secreted factors within the uterine fluid, which mediates an intermolecular transfer of EVs' cargos between blastocysts and endometrium. Emerging evidences indicate that several events like imbalance in the release of endometrial or placenta-derived EVs (exosomes/MVs), uptake of their content, failure of embryo selection might lead to implantation failure. Here in this review, we have discussed the current knowledge of the involvement of EVs in maternal-fetal communications during implantation and also highlighted the EVs' rejuvenating ability to overcome infertility-related issues. We also discussed the alteration of the EVs' cargo in different pathological conditions that lead to infertility. Therefore, this review would give a better understanding of EVs' contribution in successful embryo implantation, which could help in the development of new diagnostic tools and cell-free biologics to improve the in vivo reproductive process and to treat infertility by restoring normal reproductive functions.

RevDate: 2020-10-15

Herrera-Belaroussi A, Normand P, Pawlowski K, et al (2020)

Candidatus Frankia nodulisporulans sp. nov., an Alnus glutinosa-infective Frankia species unable to grow in pure culture and able to sporulate in-planta.

Systematic and applied microbiology, 43(6):126134 pii:S0723-2020(20)30089-8 [Epub ahead of print].

We describe a new Frankia species, for three non-isolated strains obtained from Alnus glutinosa in France and Sweden, respectively. These strains can nodulate several Alnus species (A. glutinosa, A. incana, A. alnobetula), they form hyphae, vesicles and sporangia in the root nodule cortex but have resisted all attempts at isolation in pure culture. Their genomes have been sequenced, they are significantly smaller than those of other Alnus-infective species (5Mb instead of 7.5Mb) and are very closely related to one another (ANI of 100%). The name Candidatus Frankia nodulisporulans is proposed. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene and draft genome sequences reported in this study for AgTrS, AgUmASt1 and AgUmASH1 are MT023539/LR778176/LR778180 and NZ_CADCWS000000000.1/CADDZU010000001/CADDZW010000001, respectively.

RevDate: 2020-10-15

Khasa R, Sharma P, Vaidya A, et al (2020)

Proteins involved in actin filament organization are key host factors for Japanese encephalitis virus life-cycle in human neuronal cells.

Microbial pathogenesis pii:S0882-4010(20)30931-1 [Epub ahead of print].

Multiple membrane trafficking networks operate in the eukaryotic cell and are hijacked by viruses to establish infection. Recent studied have highlighted that viruses can exploit distinct pathways depending on the cell type. Japanese encephalitis virus (JEV), a neurotropic flavivirus, can infect neuronal cells through a clathrin-independent endocytic mechanism. To further characterize the membrane trafficking requirements for JEV infection of neuronal cells, we have performed a RNA interference-based study targeting 136 proteins in the human cell line IMR-32. Through quantitative RT-PCR and plaque assays we have validated that JEV infection in neuronal cells was independent of clathrin, and identified host-factors that were crucial for establishment of infection. Several of these proteins were involved in regulation of actin filament organization such as RHOA, RAC1, proteins of the ARP2/3 complex and N-WASP family, LIMK1, PAK1 and ROCK2. The small molecule inhibitors of ARP2/3 complex, CK-548 and of the N-WASP, Wiskostatin inhibited virus replication highlighting the important roles of these proteins in the virus life-cycle. We also identified ATG12, BECN1, VAPA, VAPB and VCP proteins as crucial host-factors for JEV replication across epithelial and neuronal cell lineages.

RevDate: 2020-10-15

Prakash S, N Marimuthu (2020)

Notes on some crinoid associated decapod crustaceans (Crustacea: Decapoda) of Lakshadweep Archipelago, Central Indian Ocean.

Zootaxa, 4766(1):zootaxa.4766.1.4 pii:zootaxa.4766.1.4.

Decapod crustaceans symbiotic with echinoderms (sea stars, brittle stars, feather stars, basket stars, sea cucumbers, and sea urchins) possess remarkable diversification in the Indo-Pacific. In the present study, seven species of decapod crustaceans symbiotic with crinoids are recorded based on collections from selected Islands (Agatti, Amini, Bangaram, Kavaratti, Kalpeni, and Minicoy) of Lakshadweep Archipelago. Of these decapods, five caridean shrimps (Alpheidae: Synalpheus carinatus (de Man, 1888), S. comatularum (Haswell, 1882), S. stimpsonii (de Man, 1888); Palaemonidae: Palaemonella pottsi (Borradaile, 1915), Pontoniopsis comanthi (Borradaile, 1915), one brachyuran crab [Pilumnidae: Permanotus purpureus (Gordon, 1934)] and one squat lobster [Galatheidae: Allogalathea elegans (Adams White, 1848)] were identified. The caridean shrimps have associated with the crinoids Comaster multifidus (Müller, 1841), Phanogenia gracilis (Hartlaub, 1893), P. distincta (Carpenter, 1888), P. multibrachiata (Carpenter, 1888) and Stephanometra indica (Smith, 1876). The brachyuran crab was observed in association with the crinoid Phanogenia gracilis whereas the squat lobsters were associated with Stephanometra tenuipinna (Hartlaub, 1890) and S. indica. Except S. stimpsonii and P. purpureus, all other species were recorded for the first time from India. Here, we provide details on morphology, distribution, habitat, and hosts for all species. We recommend further exploration of the sub-shallow coral reef areas of Lakshadweep as there will be many species that certainly remain to be discovered.

RevDate: 2020-10-15

Neves K (2020)

A new species of the shrimp genus Typton Costa, 1844 (Malacostraca, Decapoda, Palaemonidae) from the Cabo Verde Archipelago.

Zootaxa, 4768(2):zootaxa.4768.2.7 pii:zootaxa.4768.2.7.

A new species of sponge-dwelling palaemonid shrimp of the genus Typton Costa, 1844 is described based on specimens collected in Enseada de Corais da Matiota, São Vicente Island, Cabo Verde. Typton anaramosae sp. nov., is the twentieth species known in this genus and is morphologically most similar to T. prionurus from the western Atlantic and T. granulosus and T. serratus from the eastern Pacific, all four sharing the serrated distal part of the outer margin of the uropodal exopod and the absence of a median tooth on the posterodorsal margin of the sixth pleonite. The more specific features, which distinguish the new species from its related congeners are discussed.

RevDate: 2020-10-15

Anker A, Al-Kandari M, S DE Grave (2020)

On two species of the alpheid shrimp genus Salmoneus Holthuis, 1955 from Kuwait, one of them new to science (Malacostraca: Decapoda: Caridea).

Zootaxa, 4780(1):zootaxa.4780.1.3 pii:zootaxa.4780.1.3.

The alpheid genus Salmoneus Holthuis, 1955 is reported from Kuwait for the first time, with two species. One species, Salmoneus ikaros sp. nov., is described based on a single specimen from Failaka Island, extracted from the burrow of the callianassid ghost-shrimp Balsscallichirus masoomi (Tirmizi, 1970), together with the host. The new species is characterised by its peculiar eyes, which together with other characters separate it from all previously described species of Salmoneus. The second species, Salmoneus gracilipes Miya, 1972, is reported from Kuwait based on three specimens from two different localities and different habitats. Two specimens were found under coral rocks at a depth of about 7 m off Kubbar Island, whereas the third specimen was extracted from the burrow of the echiuran worm, Listriolobus cf. brevirostris Chen Yeh, 1958, at the type locality of S. ikaros sp. nov. at Failaka Island. Material identified as S. gracilipes from across its wide distribution range appears to be morphologically heterogeneous, possibly containing more than one species, and thus will need further studies.

RevDate: 2020-10-15

Awais M, Ghayvat H, Krishnan Pandarathodiyil A, et al (2020)

Healthcare Professional in the Loop (HPIL): Classification of Standard and Oral Cancer-Causing Anomalous Regions of Oral Cavity Using Textural Analysis Technique in Autofluorescence Imaging.

Sensors (Basel, Switzerland), 20(20): pii:s20205780.

Oral mucosal lesions (OML) and oral potentially malignant disorders (OPMDs) have been identified as having the potential to transform into oral squamous cell carcinoma (OSCC). This research focuses on the human-in-the-loop-system named Healthcare Professionals in the Loop (HPIL) to support diagnosis through an advanced machine learning procedure. HPIL is a novel system approach based on the textural pattern of OML and OPMDs (anomalous regions) to differentiate them from standard regions of the oral cavity by using autofluorescence imaging. An innovative method based on pre-processing, e.g., the Deriche-Canny edge detector and circular Hough transform (CHT); a post-processing textural analysis approach using the gray-level co-occurrence matrix (GLCM); and a feature selection algorithm (linear discriminant analysis (LDA)), followed by k-nearest neighbor (KNN) to classify OPMDs and the standard region, is proposed in this paper. The accuracy, sensitivity, and specificity in differentiating between standard and anomalous regions of the oral cavity are 83%, 85%, and 84%, respectively. The performance evaluation was plotted through the receiver operating characteristics of periodontist diagnosis with the HPIL system and without the system. This method of classifying OML and OPMD areas may help the dental specialist to identify anomalous regions for performing their biopsies more efficiently to predict the histological diagnosis of epithelial dysplasia.

RevDate: 2020-10-15

Mayasari NR, Ho DKN, Lundy DJ, et al (2020)

Impacts of the COVID-19 Pandemic on Food Security and Diet-Related Lifestyle Behaviors: An Analytical Study of Google Trends-Based Query Volumes.

Nutrients, 12(10): pii:nu12103103.

The severe acute respiratory syndrome coronavirus (SARS-CoV)-2 disease (COVID)-19 is having profound effects on the global economy and food trade. Limited data are available on how this pandemic is affecting our dietary and lifestyle-related behaviors at the global level. Google Trends was used to obtain worldwide relative search volumes (RSVs) covering a timeframe from before the COVID-19 pandemic 1 June 2019 to 27 April 2020. Spearman's rank-order correlation coefficients were used to measure relationships between daily confirmed cases and aforementioned RSVs between 31 December 2019 and 15 April 2020. RSV curves showed increased interest in multiple keywords related to dietary and lifestyle behaviors during the COVID-19 lockdown period in March and April 2020. Spearman's correlation analysis showed that the strongest variables in each keyword category were (1) food security (food shortage: r = 0.749, food bank: r = 0.660, and free food: r = 0.555; all p < 0.001), (2) dietary behaviors (delivery: r = 0.780, restaurant: r = -0.731, take-away: r = 0.731, and food-delivery: r = 0.693; all p < 0.001), (3) outdoor-related behaviors (resort: r = -0.922, hotel: r = -0.913, cinema: r = -0.844, park: r = -0.827, fitness: r = -0.817, gym: r = -0.811; plant: r = 0.749, sunbathing: r = 0.668, and online: r = 0.670; all p < 0.001), and (4) immune-related nutrients/herbs/foods (vitamin C: r = 0.802, vitamin A: r = 0.780, zinc: r = 0.781, immune: r = 0.739, vitamin E: r = 0.707, garlic: r = 0.667, omega-3 fatty acid: r = -0.633, vitamin D: r = 0.549, and turmeric: r = 0.545; all p < 0.001). Restricted movement has affected peoples' dietary and lifestyle behaviors as people tend to search for immune-boosting nutrients/herbs and have replaced outdoor activities with sedentary indoor behaviors.

RevDate: 2020-10-14

Knudsen L, Brandenberger C, M Ochs (2020)

Stereology as the 3D tool to quantitate lung architecture.

Histochemistry and cell biology pii:10.1007/s00418-020-01927-0 [Epub ahead of print].

Stereology is the method of choice for the quantitative assessment of biological objects in microscopy. It takes into account the fact that, in traditional microscopy such as conventional light and transmission electron microscopy, although one has to rely on measurements on nearly two-dimensional sections from fixed and embedded tissue samples, the quantitative data obtained by these measurements should characterize the real three-dimensional properties of the biological objects and not just their "flatland" appearance on the sections. Thus, three-dimensionality is a built-in property of stereological sampling and measurement tools. Stereology is, therefore, perfectly suited to be combined with 3D imaging techniques which cover a wide range of complementary sample sizes and resolutions, e.g. micro-computed tomography, confocal microscopy and volume electron microscopy. Here, we review those stereological principles that are of particular relevance for 3D imaging and provide an overview of applications of 3D imaging-based stereology to the lung in health and disease. The symbiosis of stereology and 3D imaging thus provides the unique opportunity for unbiased and comprehensive quantitative characterization of the three-dimensional architecture of the lung from macro to nano scale.

RevDate: 2020-10-16

Shelly A, Gupta P, Ahuja R, et al (2020)

Impact of Microbiota: A Paradigm for Evolving Herd Immunity against Viral Diseases.

Viruses, 12(10): pii:v12101150.

Herd immunity is the most critical and essential prophylactic intervention that delivers protection against infectious diseases at both the individual and community level. This process of natural vaccination is immensely pertinent to the current context of a pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection around the globe. The conventional idea of herd immunity is based on efficient transmission of pathogens and developing natural immunity within a population. This is entirely encouraging while fighting against any disease in pandemic circumstances. A spatial community is occupied by people having variable resistance capacity against a pathogen. Protection efficacy against once very common diseases like smallpox, poliovirus or measles has been possible only because of either natural vaccination through contagious infections or expanded immunization programs among communities. This has led to achieving herd immunity in some cohorts. The microbiome plays an essential role in developing the body's immune cells for the emerging competent vaccination process, ensuring herd immunity. Frequency of interaction among microbiota, metabolic nutrients and individual immunity preserve the degree of vaccine effectiveness against several pathogens. Microbiome symbiosis regulates pathogen transmissibility and the success of vaccination among different age groups. Imbalance of nutrients perturbs microbiota and abrogates immunity. Thus, a particular population can become vulnerable to the infection. Intestinal dysbiosis leads to environmental enteropathy (EE). As a consequence, the generation of herd immunity can either be delayed or not start in a particular cohort. Moreover, disparities of the protective response of many vaccines in developing countries outside of developed countries are due to inconsistencies of healthy microbiota among the individuals. We suggested that pan-India poliovirus vaccination program, capable of inducing herd immunity among communities for the last 30 years, may also influence the inception of natural course of heterologous immunity against SARS-CoV-2 infection. Nonetheless, this anamnestic recall is somewhat counterintuitive, as antibody generation against original antigens of SARS-CoV-2 will be subdued due to original antigenic sin.

RevDate: 2020-10-16
CmpDate: 2020-10-16

Vera-Ponce de León A, Jahnes BC, Duan J, et al (2020)

Cultivable, Host-Specific Bacteroidetes Symbionts Exhibit Diverse Polysaccharolytic Strategies.

Applied and environmental microbiology, 86(8):.

Beneficial gut microbes can facilitate insect growth on diverse diets. The omnivorous American cockroach, Periplaneta americana (Insecta: Blattodea), thrives on a diet rich in plant polysaccharides and harbors a species-rich gut microbiota responsive to host diet. Bacteroidetes are among the most abundant taxa in P. americana and other cockroaches, based on cultivation-independent gut community profiling, and these potentially polysaccharolytic bacteria may contribute to host diet processing. Eleven Bacteroidetes isolates were cultivated from P. americana digestive tracts, and phylogenomic analyses suggest that they were new Bacteroides, Dysgonomonas, Paludibacter, and Parabacteroides species distinct from those previously isolated from other insects, humans, and environmental sources. In addition, complete genomes were generated for each isolate, and polysaccharide utilization loci (PULs) and several non-PUL-associated carbohydrate-active enzyme (CAZyme)-coding genes that putatively target starch, pectin, and/or cellulose were annotated in each of the isolate genomes. Type IX secretion system (T9SS)- and CAZyme-coding genes tagged with the corresponding T9SS recognition and export C-terminal domain were observed in some isolates, suggesting that these CAZymes were deployed via non-PUL outer membrane translocons. Additionally, single-substrate growth and enzymatic assays confirmed genomic predictions that a subset of the Bacteroides and Dysgonomonas isolates could degrade starch, pectin, and/or cellulose and grow in the presence of these substrates as a single sugar source. Plant polysaccharides enrich P. americana diets, and many of these gut isolates are well equipped to exploit host dietary inputs and potentially contribute to gut community and host nutrient accessibility.IMPORTANCE Gut microbes are increasingly being recognized as critical contributors to nutrient accessibility in animals. The globally distributed omnivorous American cockroach (Periplaneta americana) harbors many bacterial phyla (e.g., Bacteroidetes) that are abundant in vertebrates. P. americana thrives on a highly diverse plant-enriched diet, making this insect a rich potential source of uncharacterized polysaccharolytic bacteria. We have cultivated, completely sequenced, and functionally characterized several novel Bacteroidetes species that are endemic to the P. americana gut, and many of these isolates can degrade simple and complex polysaccharides. Cultivation and genomic characterization of these Bacteroidetes isolates further enable deeper insight into how these taxa participate in polysaccharide metabolism and, more broadly, how they affect animal health and development.

RevDate: 2020-10-16
CmpDate: 2020-10-16

Jiang L, Liu X, Dong C, et al (2020)

"Candidatus Desulfobulbus rimicarensis," an Uncultivated Deltaproteobacterial Epibiont from the Deep-Sea Hydrothermal Vent Shrimp Rimicaris exoculata.

Applied and environmental microbiology, 86(8):.

The deep-sea hydrothermal vent shrimp Rimicaris exoculata largely depends on a dense epibiotic chemoautotrophic bacterial community within its enlarged cephalothoracic chamber. However, our understanding of shrimp-bacterium interactions is limited. In this report, we focused on the deltaproteobacterial epibiont of R. exoculata from the relatively unexplored South Mid-Atlantic Ridge. A nearly complete genome of a Deltaproteobacteria epibiont was binned from the assembled metagenome. Whole-genome phylogenetic analysis reveals that it is affiliated with the genus Desulfobulbus, representing a potential novel species for which the name "Candidatus Desulfobulbus rimicarensis" is proposed. Genomic and transcriptomic analyses reveal that this bacterium utilizes the Wood-Ljungdahl pathway for carbon assimilation and harvests energy via sulfur disproportionation, which is significantly different from other shrimp epibionts. Additionally, this epibiont has putative nitrogen fixation activity, but it is extremely active in directly taking up ammonia and urea from the host or vent environments. Moreover, the epibiont could be distinguished from its free-living relatives by various features, such as the lack of chemotaxis and motility traits, a dramatic reduction in biosynthesis genes for capsular and extracellular polysaccharides, enrichment of genes required for carbon fixation and sulfur metabolism, and resistance to environmental toxins. Our study highlights the unique role and symbiotic adaptation of Deltaproteobacteria in deep-sea hydrothermal vent shrimps.IMPORTANCE The shrimp Rimicaris exoculata represents the dominant faunal biomass at many deep-sea hydrothermal vent ecosystems along the Mid-Atlantic Ridge. This organism harbors dense bacterial epibiont communities in its enlarged cephalothoracic chamber that play an important nutritional role. Deltaproteobacteria are ubiquitous in epibiotic communities of R. exoculata, and their functional roles as epibionts are based solely on the presence of functional genes. Here, we describe "Candidatus Desulfobulbus rimicarensis," an uncultivated deltaproteobacterial epibiont. Compared to campylobacterial and gammaproteobacterial epibionts of R. exoculata, this bacterium possessed unique metabolic pathways, such as the Wood-Ljungdahl pathway, as well as sulfur disproportionation and nitrogen fixation pathways. Furthermore, this epibiont can be distinguished from closely related free-living Desulfobulbus strains by its reduced genetic content and potential loss of functions, suggesting unique adaptations to the shrimp host. This study is a genomic and transcriptomic analysis of a deltaproteobacterial epibiont and largely expands the understanding of its metabolism and adaptation to the R. exoculata host.

RevDate: 2020-10-16
CmpDate: 2020-10-16

Speare L, Smith S, Salvato F, et al (2020)

Environmental Viscosity Modulates Interbacterial Killing during Habitat Transition.

mBio, 11(1):.

Symbiotic bacteria use diverse strategies to compete for host colonization sites. However, little is known about the environmental cues that modulate interbacterial competition as they transition between free-living and host-associated lifestyles. We used the mutualistic relationship between Eupyrmna scolopes squid and Vibrio fischeri bacteria to investigate how intraspecific competition is regulated as symbionts move from the seawater to a host-like environment. We recently reported that V. fischeri uses a type VI secretion system (T6SS) for intraspecific competition during host colonization. Here, we investigated how environmental viscosity impacts T6SS-mediated competition by using a liquid hydrogel medium that mimics the viscous host environment. Our data demonstrate that although the T6SS is functionally inactive when cells are grown under low-viscosity liquid conditions similar to those found in seawater, exposure to a host-like high-viscosity hydrogel enhances T6SS expression and sheath formation, activates T6SS-mediated killing in as little as 30 min, and promotes the coaggregation of competing genotypes. Finally, the use of mass spectrometry-based proteomics revealed insights into how cells may prepare for T6SS competition during this habitat transition. These findings, which establish the use of a new hydrogel culture condition for studying T6SS interactions, indicate that V. fischeri rapidly responds to the physical environment to activate the competitive mechanisms used during host colonization.IMPORTANCE Bacteria often engage in interference competition to gain access to an ecological niche, such as a host. However, little is known about how the physical environment experienced by free-living or host-associated bacteria influences such competition. We used the bioluminescent squid symbiont Vibrio fischeri to study how environmental viscosity impacts bacterial competition. Our results suggest that upon transition from a planktonic environment to a host-like environment, V. fischeri cells activate their type VI secretion system, a contact-dependent interbacterial nanoweapon, to eliminate natural competitors. This work shows that competitor cells form aggregates under host-like conditions, thereby facilitating the contact required for killing, and reveals how V. fischeri regulates a key competitive mechanism in response to the physical environment.

RevDate: 2020-10-16
CmpDate: 2020-10-16

Znaidi S (2020)

mSphere of Influence: Decoding Transcriptional Regulatory Networks To Illuminate the Mechanisms of Microbial Pathogenicity.

mSphere, 5(1):.

Sadri Znaidi works in the field of molecular mycology with a focus on functional genomics in Candida albicans In this mSphere of Influence article, he reflects on how the paper "An iron homeostasis regulatory circuit with reciprocal roles in Candida albicans commensalism and pathogenesis" by Chen et al. (C. Chen, K. Pande, S. D. French, B. B. Tuch, and S. M. Noble, Cell Host Microbe 10:118-135, 2011, made an impact on his research on how transcriptional regulatory networks function to control C. albicans' ability to efficiently interact with the host environment.

RevDate: 2020-10-15
CmpDate: 2020-10-15

Wall CB, Kaluhiokalani M, Popp BN, et al (2020)

Divergent symbiont communities determine the physiology and nutrition of a reef coral across a light-availability gradient.

The ISME journal, 14(4):945-958.

Reef corals are mixotrophic organisms relying on symbiont-derived photoautotrophy and water column heterotrophy. Coral endosymbionts (Family: Symbiodiniaceae), while typically considered mutualists, display a range of species-specific and environmentally mediated opportunism in their interactions with coral hosts, potentially requiring corals to rely more on heterotrophy to avoid declines in performance. To test the influence of symbiont communities on coral physiology (tissue biomass, symbiont density, photopigmentation) and nutrition (δ13C, δ15N), we sampled Montipora capitata colonies dominated by a specialist symbiont Cladocopium spp. or a putative opportunist Durusdinium glynnii (hereafter, C- or D-colonies) from Kāne'ohe Bay, Hawai'i, across gradients in photosynthetically active radiation (PAR) during summer and winter. We report for the first time that isotope values of reef corals are influenced by Symbiodiniaceae communities, indicative of different autotrophic capacities among symbiont species. D-colonies had on average 56% higher symbiont densities, but lower photopigments per symbiont cell and consistently lower δ13C values in host and symbiont tissues; this pattern in isotope values is consistent with lower symbiont carbon assimilation and translocation to the host. Neither C- nor D-colonies showed signs of greater heterotrophy or nutritional plasticity; instead changes in δ13C values were driven by PAR availability and photoacclimation attributes that differed between symbiont communities. Together, these results reveal Symbiodiniaceae functional diversity produces distinct holobionts with different capacities for autotrophic nutrition, and energy tradeoffs from associating with opportunist symbionts are not met with increased heterotrophy.

RevDate: 2020-10-15
CmpDate: 2020-10-15

Arai H, Lin SR, Nakai M, et al (2020)

Closely Related Male-Killing and Nonmale-Killing Wolbachia Strains in the Oriental Tea Tortrix Homona magnanima.

Microbial ecology, 79(4):1011-1020.

Wolbachia are inherited intracellular bacteria that cause male-specific death in some arthropods, called male-killing. To date, three Wolbachia strains have been identified in the oriental tea tortrix Homona magnanima (Tortricidae, Lepidoptera); however, none of these caused male-killing in the Japanese population. Here, we describe a male-killing Wolbachia strain in Taiwanese H. magnanima. From field-collected H. magnanima, two female-biased host lines were established, and antibiotic treatments revealed Wolbachia (wHm-t) as the causative agent of male-killing. The wsp and MLST genes in wHm-t are identical to corresponding genes in the nonmale-killing strain wHm-c from the Japanese population, implying a close relationship of the two strains. Crossing the Japanese and Taiwanese H. magnanima revealed that Wolbachia genotype rather than the host genetic background was responsible for the presence of the male-killing phenotype. Quantitative PCR analyses revealed that the density of wHm-t was higher than that of other Wolbachia strains in H. magnanima, including wHm-c. The densities of wHm-t were also heterogeneous between host lines. Notably, wHm-t in the low-density and high-density lines carried identical wsp and MLST genes but had distinct lethal patterns. Furthermore, over 90% of field-collected lines of H. magnanima in Taiwan were infected with wHm-t, although not all host lines harboring wHm-t showed male-killing. The host lines that showed male-killing harbored a high density of Wolbachia compared to the host lines that did not show male-killing. Thus, the differences in the phenotypes appear to be dependent on biological and genetic characteristics of closely related Wolbachia strains.

RevDate: 2020-10-15
CmpDate: 2020-10-15

Khan KA, Al-Ghamdi AA, Ghramh HA, et al (2020)

Structural diversity and functional variability of gut microbial communities associated with honey bees.

Microbial pathogenesis, 138:103793.

Microbial consortia accompanied to all eukaryotes can be inherited from ancestors, environment, and/or from various food source. Gut microbiota study is an emerging discipline of biological sciences that expands our understanding of the ecological and functional dynamics of gut environments. Microorganisms associated with honey bees play an important role in food digestion, colony performance, immunity, pollination, antagonistic effect against different pathogens, amelioration of food and many more. Although, many repots about honey bee gut microbiota are well documented, microbiome with other key components of honey bees such as larvae, adults, their food (pollen, beebread, and honey), honey combs, and floral nectar are poorly understood. Mutual interactions and extent of the roles of microbial communities associated with honey bees are still unclear and demand for more research on the nutritional physiology and health benefits of this ecologically and economically important group. Here in this study, we highlighted all the honey bee microbiome that harbored from different life stages and other relevant components. The anatomical parts of honey bee (larvae, adults), food source (pollen, beebread, and honey), honey combs, and floral nectar were highly flourished by numerous microorganisms like bacteria (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Actinobacteria, Actinomycetes, Bacilli, Bacteroidetes, Cocci, Clostridia, Coliforms, Firmicutes, Flavobacteriia, Mollicutes) and fungi (Dothideomycetes, Eurotiomycetes, Mucormycotina, Saccharomycetes, Zygomycetes, Yeasts, Molds). Some distinctive microbial communities of a taxonomically constrained species have coevolved with social bees. This contribution is to enhance the understanding of honey bee gut microbiota, to accelerate bee microbiota and microbiome research in general and to aid design of future experiments in this growing field.

RevDate: 2020-10-15
CmpDate: 2020-10-15

Pontarollo G, Mann A, Brandão I, et al (2020)

Protease-activated receptor signaling in intestinal permeability regulation.

The FEBS journal, 287(4):645-658.

Protease-activated receptors (PARs) are a unique class of G-protein-coupled transmembrane receptors, which revolutionized the perception of proteases from degradative enzymes to context-specific signaling factors. Although PARs are traditionally known to affect several vascular responses, recent investigations have started to pinpoint the functional role of PAR signaling in the gastrointestinal (GI) tract. This organ is exposed to the highest number of proteases, either from the gut lumen or from the mucosa. Luminal proteases include the host's digestive enzymes and the proteases released by the commensal microbiota, while mucosal proteases entail extravascular clotting factors and the enzymes released from resident and infiltrating immune cells. Active proteases and, in case of a disrupted gut barrier, even entire microorganisms are capable to translocate the intestinal epithelium, particularly under inflammatory conditions. Especially PAR-1 and PAR-2, expressed throughout the GI tract, impact gut permeability regulation, a major factor affecting intestinal physiology and metabolic inflammation. In addition, PARs are critically involved in the onset of inflammatory bowel diseases, irritable bowel syndrome, and tumor progression. Due to the number of proteases involved and the multiple cell types affected, selective regulation of intestinal PARs represents an interesting therapeutic strategy. The analysis of tissue/cell-specific knockout animal models will be of crucial importance to unravel the intrinsic complexity of this signaling network. Here, we provide an overview on the implication of PARs in intestinal permeability regulation under physiologic and disease conditions.

RevDate: 2020-10-14
CmpDate: 2020-10-14

Santolamazza-Carbone S, Durán-Otero M, M Calviño-Cancela (2019)

Context dependency, co-introductions, novel mutualisms, and host shifts shaped the ectomycorrhizal fungal communities of the alien tree Eucalyptus globulus.

Scientific reports, 9(1):7121 pii:10.1038/s41598-019-42550-x.

The identity and relevance of the ectomycorrhizal (ECM) fungal partners of Eucalyptus globulus was investigated in NW Spain, to detect which symbionts mainly support its invasiveness. Root tips of E. globulus and of three common native plant species (Quercus robur, Pinus pinaster and Halimium lasianthum) were collected in eucalypt plantations, Q. robur forests, P. pinaster plantations and shrublands. Fungal taxonomical identity was ascertained by use of rDNA and direct sequencing. We studied diversity, composition and colonization rate of the ECM fungal communities of E. globulus to determine if fungal assemblages are host specific (i.e. similar in different habitats) or more dependent on the neighbourhood context. We also identified the type of associations formed (i.e. co-introductions, familiar or novel associations). Twenty-six ECM taxa were associated with E. globulus. Most of them engaged in novel associations with eucalypts, whereas only three fungal species were co-introduced Australian aliens. Eucalypt fungal richness, diversity and colonization rate differed between habitats, being higher in native oak forests, whereas in shrublands E. globulus showed the lowest colonization rate and diversity. The Australian fungus Descolea maculata dominated the eucalypt fungal assemblage and also spread to the native host plants, in all the habitats, posing the risk of further co-invasion.

RevDate: 2020-10-15
CmpDate: 2020-10-15

Zhu B, Macleod LC, Newsome E, et al (2019)

Aggregatibacter actinomycetemcomitans mediates protection of Porphyromonas gingivalis from Streptococcus sanguinis hydrogen peroxide production in multi-species biofilms.

Scientific reports, 9(1):4944 pii:10.1038/s41598-019-41467-9.

Mixed species biofilms are shaped and influenced by interactions between species. In the oral cavity, dysbiosis of the microbiome leads to diseases such as periodontitis. Porphyromonas gingivalis is a keystone pathogen of periodontitis. In this study, we showed that polymicrobial biofilm formation promoted the tolerance of Porphyromonas gingivalis to oxidative stress under micro-aerobic conditions. The presence of Streptococcus sanguinis, an oral commensal bacterium, inhibited the survival of P. gingivalis in dual-species biofilms via the secretion of hydrogen peroxide (H2O2). Interestingly, this repression could be attenuated by the presence of Aggregatibacter actinomycetemcomitans in tri-species biofilms. It was also shown that the katA gene, encoding a cytoplasmic catalase in A. actinomycetemcomitans, was responsible for the reduction of H2O2 produced by S. sanguinis, which consequently increased the biomass of P. gingivalis in tri-species biofilms. Collectively, these findings reveal that polymicrobial interactions play important roles in shaping bacterial community in biofilm. The existence of catalase producers may support the colonization of pathogens vulnerable to H2O2, in the oral cavity. The catalase may be a potential drug target to aid in the prevention of periodontitis.

RevDate: 2020-10-13

Stoy KS, Gibson AK, Gerardo NM, et al (2020)

A need to consider the evolutionary genetics of host-symbiont mutualisms.

Journal of evolutionary biology [Epub ahead of print].

Despite the ubiquity and importance of mutualistic interactions, we know little about the evolutionary genetics underlying their long-term persistence. As in antagonistic interactions, mutualistic symbioses are characterized by substantial levels of phenotypic and genetic diversity. In contrast to antagonistic interactions, however, we, by and large, do not understand how this variation arises, how it is maintained, nor its implications for future evolutionary change. Currently, we rely on phenotypic models to address the persistence of mutualistic symbioses, but the success of an interaction almost certainly depends heavily on genetic interactions. In this review, we argue that evolutionary genetic models could provide a framework for understanding the causes and consequences of diversity and why selection may favor processes that maintain variation in mutualistic interactions.

RevDate: 2020-10-13

Miyauchi S, Kiss E, Kuo A, et al (2020)

Large-scale genome sequencing of mycorrhizal fungi provides insights into the early evolution of symbiotic traits.

Nature communications, 11(1):5125 pii:10.1038/s41467-020-18795-w.

Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.

RevDate: 2020-10-12

Singh A, Jha A, S Purbey (2020)

Identification of Measures Affecting Job Satisfaction and Levels of Perceived Stress and Burnout among Home Health Nurses of a Developing Asian Country.

Hospital topics [Epub ahead of print].

BACKGROUND: Factors affecting job satisfaction of home health nurses are studied.

METHODS: PSS-10, CBI and HHNJS are used to measure the perceived stress, burnout of home health nurses and Job Satisfaction.

RESULTS: The significant predictors for Job satisfaction were Relationship with organization, Autonomy and control, Salary and Benefits as 82% of variation in job satisfaction was explained by these, (F change (3, 144) = 236.72, p < .001).

CONCLUSION: Agencies should work upon improving the dimensions such as the "relationship with the organization", "Autonomy and control" and "Salary and Benefits" to increases the Job satisfaction of home health nurses.

RevDate: 2020-10-12

Robledo M, García-Tomsig NI, Matia-González AM, et al (2020)

Synthetase of the methyl donor S-adenosylmethionine from nitrogen-fixing α-rhizobia can bind functionally diverse RNA species.

RNA biology [Epub ahead of print].

Function of bacterial small non-coding RNAs (sRNAs) and overall RNA metabolism is largely shaped by a vast diversity of RNA-protein interactions. However, in non-model bacteria with defined non-coding transcriptomes the sRNA interactome remains almost unexplored. We used affinity chromatography to capture proteins associated in vivo with MS2-tagged trans-sRNAs that regulate nutrient uptake (AbcR2 and NfeR1) and cell cycle (EcpR1) mRNAs by antisense-based translational inhibition in the nitrogen-fixing α-rhizobia Sinorhizobium meliloti. The three proteomes were rather distinct, with that of EcpR1 particularly enriched in cell cycle-related enzymes, whilst sharing several transcription/translation-related proteins recurrently identified associated with sRNAs. Strikingly, MetK, the synthetase of the major methyl donor S-adenosylmethionine, was reliably recovered as a binding partner of the three sRNAs, which reciprocally co-immunoprecipitated with a FLAG-tagged MetK variant. Induced (over)expression of the trans-sRNAs and MetK depletion did not influence canonical riboregulatory traits, `for example, protein titration or sRNA stability, respectively. An in vitro filter assay confirmed binding of AbcR2, NfeR1 and EcpR1 to MetK and further revealed interaction of the protein with other non-coding and coding transcripts but not with the 5S rRNA. These findings uncover a broad specificity for RNA binding as an unprecedented feature of this housekeeping prokaryotic enzyme.

RevDate: 2020-10-12

Vohník M (2020)

Ericoid mycorrhizal symbiosis: theoretical background and methods for its comprehensive investigation.

Mycorrhiza pii:10.1007/s00572-020-00989-1 [Epub ahead of print].

Despite decades of intensive research (especially from 1970s to 1990s), the ericoid mycorrhizal (ErM) hair root is still largely terra incognita and this simplified guide is intended to revive and promote the study of its mycobiota. Basic theoretical knowledge on the ErM symbiosis is summarized, followed by practical advices on Ericaceae root sample collection and handling, microscopic observations and photo-documentation of root fungal colonization, mycobiont isolation, maintenance and identification and resynthesis experiments with ericoid plants. The necessity of a proper selection of the root material and its surface sterilization prior to mycobiont isolation is stressed, together with the need of including suitable control treatments in inoculation experiments. The culture-dependent approach employing plating of single short (~ 2 mm) hair root segments on nutrient media is substantiated as a useful tool for characterization of Ericaceae root-associated fungal communities; it targets living mycelium and provides metabolically active cultures that can be used in physiological experiments and taxonomic studies, thus providing essential reference material for culture-independent approaches. On the other hand, it is stressed that not every mycobiont isolated from an ericoid hair root necessarily represent an ErM fungus. Likewise, not every intracellular hyphal coil formed in the Ericaceae rhizodermis necessarily represents the ErM symbiosis. Taxonomy of the most important ericoid mycobionts is updated, mutualism in the ErM symbiosis is briefly discussed from the mycobiont perspective, and some interesting lines of possible future research are highlighted.

RevDate: 2020-10-13

Roux N, Salis P, Lee SH, et al (2020)

Anemonefish, a model for Eco-Evo-Devo.

EvoDevo, 11:20.

Anemonefish, are a group of about 30 species of damselfish (Pomacentridae) that have long aroused the interest of coral reef fish ecologists. Combining a series of original biological traits and practical features in their breeding that are described in this paper, anemonefish are now emerging as an experimental system of interest for developmental biology, ecology and evolutionary sciences. They are small sized and relatively easy to breed in specific husbandries, unlike the large-sized marine fish used for aquaculture. Because they live in highly structured social groups in sea anemones, anemonefish allow addressing a series of relevant scientific questions such as the social control of growth and sex change, the mechanisms controlling symbiosis, the establishment and variation of complex color patterns, and the regulation of aging. Combined with the use of behavioral experiments, that can be performed in the lab or directly in the wild, as well as functional genetics and genomics, anemonefish provide an attractive experimental system for Eco-Evo-Devo.

RevDate: 2020-10-13

Sharma MP, Grover M, Chourasiya D, et al (2020)

Deciphering the Role of Trehalose in Tripartite Symbiosis Among Rhizobia, Arbuscular Mycorrhizal Fungi, and Legumes for Enhancing Abiotic Stress Tolerance in Crop Plants.

Frontiers in microbiology, 11:509919.

Drought is a critical factor limiting the productivity of legumes worldwide. Legumes can enter into a unique tripartite symbiotic relationship with root-nodulating bacteria of genera Rhizobium, Bradyrhizobium, or Sinorhizobium and colonization by arbuscular mycorrhizal fungi (AMF). Rhizobial symbiosis provides nitrogen necessary for growth. AMF symbiosis enhances uptake of diffusion-limited nutrients such as P, Zn, Cu, etc., and also water from the soil via plant-associated fungal hyphae. Rhizobial and AMF symbioses can act synergistically in promoting plant growth and fitness, resulting in overall yield benefits under drought stress. One of the approaches that rhizobia use to survive under stress is the accumulation of compatible solutes, or osmolytes, such as trehalose. Trehalose is a non-reducing disaccharide and an osmolyte reported to accumulate in a range of organisms. High accumulation of trehalose in bacteroids during nodulation protects cells and proteins from osmotic shock, desiccation, and heat under drought stress. Manipulation of trehalose cell concentrations has been directly correlated with stress response in plants and other organisms, including AMF. However, the role of this compound in the tripartite symbiotic relationship is not fully explored. This review describes the biological importance and the role of trehalose in the tripartite symbiosis between plants, rhizobia, and AMF. In particular, we review the physiological functions and the molecular investigations of trehalose carried out using omics-based approaches. This review will pave the way for future studies investigating possible metabolic engineering of this biomolecule for enhancing abiotic stress tolerance in plants.

RevDate: 2020-10-12

Rosset SL, Oakley CA, Ferrier-Pagès C, et al (2020)

The Molecular Language of the Cnidarian-Dinoflagellate Symbiosis.

Trends in microbiology pii:S0966-842X(20)30232-8 [Epub ahead of print].

The cnidarian-dinoflagellate symbiosis is of huge importance as it underpins the success of coral reefs, yet we know very little about how the host cnidarian and its dinoflagellate endosymbionts communicate with each other to form a functionally integrated unit. Here, we review the current knowledge of interpartner molecular signaling in this symbiosis, with an emphasis on lipids, glycans, reactive species, biogenic volatiles, and noncoding RNA. We draw upon evidence of these compounds from recent omics-based studies of cnidarian-dinoflagellate symbiosis and discuss the signaling roles that they play in other, better-studied symbioses. We then consider how improved knowledge of interpartner signaling might be used to develop solutions to the coral reef crisis by, for example, engineering more thermally resistant corals.

RevDate: 2020-10-12

Brown JJ, Rodríguez-Ruano SM, Poosakkannu A, et al (2020)

Ontogeny, species identity, and environment dominate microbiome dynamics in wild populations of kissing bugs (Triatominae).

Microbiome, 8(1):146 pii:10.1186/s40168-020-00921-x.

BACKGROUND: Kissing bugs (Triatominae) are blood-feeding insects best known as the vectors of Trypanosoma cruzi, the causative agent of Chagas' disease. Considering the high epidemiological relevance of these vectors, their biology and bacterial symbiosis remains surprisingly understudied. While previous investigations revealed generally low individual complexity but high among-individual variability of the triatomine microbiomes, any consistent microbiome determinants have not yet been identified across multiple Triatominae species.

METHODS: To obtain a more comprehensive view of triatomine microbiomes, we investigated the host-microbiome relationship of five Triatoma species sampled from white-throated woodrat (Neotoma albigula) nests in multiple locations across the USA. We applied optimised 16S rRNA gene metabarcoding with a novel 18S rRNA gene blocking primer to a set of 170 T. cruzi-negative individuals across all six instars.

RESULTS: Triatomine gut microbiome composition is strongly influenced by three principal factors: ontogeny, species identity, and the environment. The microbiomes are characterised by significant loss in bacterial diversity throughout ontogenetic development. First instars possess the highest bacterial diversity while adult microbiomes are routinely dominated by a single taxon. Primarily, the bacterial genus Dietzia dominates late-stage nymphs and adults of T. rubida, T. protracta, and T. lecticularia but is not present in the phylogenetically more distant T. gerstaeckeri and T. sanguisuga. Species-specific microbiome composition, particularly pronounced in early instars, is further modulated by locality-specific effects. In addition, pathogenic bacteria of the genus Bartonella, acquired from the vertebrate hosts, are an abundant component of Triatoma microbiomes.

CONCLUSION: Our study is the first to demonstrate deterministic patterns in microbiome composition among all life stages and multiple Triatoma species. We hypothesise that triatomine microbiome assemblages are produced by species- and life stage-dependent uptake of environmental bacteria and multiple indirect transmission strategies that promote bacterial transfer between individuals. Altogether, our study highlights the complexity of Triatominae symbiosis with bacteria and warrant further investigation to understand microbiome function in these important vectors. Video abstract.

RevDate: 2020-10-12

Chaturvedi R, Favas PJC, Pratas J, et al (2020)

Harnessing Pisum sativum-Glomus mosseae symbiosis for phytoremediation of soil contaminated with lead, cadmium, and arsenic.

International journal of phytoremediation [Epub ahead of print].

This study investigates the impact of Glomus mosseae on heavy metal(loid) (HM) uptake efficiency of pea (Pisum sativum L.) plants along with physiological and biochemical parameters. Plants were grown in soil spiked with HMs (Pb and As: 50 and 100 mg kg-1; Cd: 25 and 50 mg kg-1) and a multi-metal(loid) (Mm: Pb + Cd + As) combination, inoculated/non-inoculated with G. mosseae. A dose-dependent increase in HM accumulation was observed in plants upon harvest at 60 days. Plant growth, concentration of photosynthetic pigments, total nitrogen, and carbohydrates reduced, whereas enzymatic [catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX)] and non-enzymatic (proline and total phenolics) antioxidants increased upon HM stress. Inoculation with G. mosseae led to an increase in plant growth, concentration of photosynthetic pigments, carbohydrate, nitrogen, and defence antioxidants (whereas proline decreased) which was statistically significant (p ≤ 0.05). This symbiosis can be applied for onsite remediation of Pb and Cd contaminated soil by virtue of accumulation efficiency and adaptive response of pea plants inoculated with G. mosseae. Since the amount of HMs in edible parts exceeded the maximum permissible limits recommended by FAO/WHO, pea must not be cultivated in HM-contaminated soil for agricultural purpose due to associated toxicity. Novelty statement To our knowledge, phytoremediation potential of Pea in synchronization with Glomus mosseae has not been evaluated previously. This study highlights: • Pea-AMF symbiosis can be applied for Pb and/or Cd phytoremediation. • Target Hazard Quotient >1 for Pb, Cd and As; caution to food chain exposure required. • Nonenzymatic (proline, TPC) and enzymatic (CAT, SOD, APX) antioxidants play a key role in ROS detoxification.

RevDate: 2020-10-13

Wang J, Lei Z, Wei Y, et al (2020)

Behavior of algal-bacterial granular sludge in a novel closed photo-sequencing batch reactor under no external O2 supply.

Bioresource technology, 318:124190 pii:S0960-8524(20)31464-4 [Epub ahead of print].

Algal-bacterial aerobic granular sludge (AB-AGS) as a symbiosis system possesses high potential for being operated without external O2 supply. In this study, a novel lab-scale closed photo-sequencing batch reactor (PSBR) was developed for AB-AGS operation under successively open (Phase Ⅰ) and closed (Phase Ⅱ) conditions. Results show that AB-AGS maintained almost 100% of organics removal, exhibiting higher removals of phosphate (63 ± 20%), K+ (19 ± 12%) and Mg2+ (26 ± 12%), and higher chlorophylls content during Phase II. Meanwhile, only O2 besides N2 was detectable in the headspace of PSBR. The change of granular structure and faster algae growth during Phase Ⅱ may contribute to the increase of microbial activity and phosphorus bioavailability, in which lower extracellular polymeric substances content may account for low biomass retention. Results from this closed PSBR imply that AB-AGS has the potential to reduce some greenhouse gases like CO2 and CH4 emission.

RevDate: 2020-10-10

Scardaci R, Varese F, Manfredi M, et al (2020)

Enterococcus faecium NCIMB10415 responds to norepinephrine by altering protein profiles and phenotypic characters.

Journal of proteomics pii:S1874-3919(20)30371-7 [Epub ahead of print].

The long-term established symbiosis between gut microbiota and humans is based upon a dynamic equilibrium that, if unbalanced, could lead to the development of diseases. Despite the huge amount of data concerning the microbiota-gut-brain-axis, little information is available on what happens at the molecular level in bacteria, when exposed to human signals. In the present study, the physiological effects exerted by norepinephrine (NE), a human hormone present in significant amounts in the host gut, were analyzed using the commensal/probiotic strain Enterococcus faecium NCIMB10415 as a target. The aim was to compare the protein profiles of treated and untreated bacteria and relating these proteome patterns to some phenotypic modifications important for bacteria-host interaction. Actually, to date, only pathogens were considered. Combining a gel-free/label-free proteomic analysis with the evaluation of bile salts resistance, biofilm formation and autoaggregation ability (as well as with the bacterial growth kinetics), allowed to detect changes induced by NE treatment on all the tested probiotic properties. Furthermore, exposure to the bioactive molecule increased the abundance of proteins related to stress response and to host-microbe interaction, such as moonlight proteins involved in adhesion and immune stimulation. The results of this investigation demonstrated that, not only pathogens, but also commensal gut bacteria are affected by host-derived hormones, underlining the importance of a correct cross-signalling in the maintenance of gut homeostasis. SIGNIFICANCE: The crucial role played by the human gut microbiota in ensuring host homeostasis and health is definitively ascertained as suggested by the holobiome concept. The present research was intended to shed light on the endocrinological perturbations possibly affecting microbiota. The microbial model used in this study belongs to Enterococcus faecium species, whose controversial role as gut commensal and opportunistic pathogen in the gut ecosystem is well recognized. The results obtained in the present investigation clearly demonstrate that E. faecium NCIMB10415 can sense and respond to norepinephrine, a human hormone abundant at the gut level, by changing protein profiles and physiology, inducing changes that could favor survival and colonization of the host tissues. To our knowledge, this is the first report concerning the impact of human hormones on commensal/probiotic bacteria, since previous research has focused on exploring the effects of neuroendocrine molecules on growth and virulence of pathogenic species.

RevDate: 2020-10-11

Diller M, Johnson E, Hicks A, et al (2020)

A realism-based approach to an ontological representation of symbiotic interactions.

BMC medical informatics and decision making, 20(1):258.

BACKGROUND: The symbiotic interactions that occur between humans and organisms in our environment have a tremendous impact on our health. Recently, there has been a surge in interest in understanding the complex relationships between the microbiome and human health and host immunity against microbial pathogens, among other things. To collect and manage data about these interactions and their complexity, scientists will need ontologies that represent symbiotic interactions as they occur in reality.

METHODS: We began with two papers that reviewed the usage of 'symbiosis' and related terms in the biology and ecology literature and prominent textbooks. We then analyzed several prominent standard terminologies and ontologies that contain representations of symbiotic interactions, to determine if they appropriately defined 'symbiosis' and related terms according to current scientific usage as identified by the review papers. In the process, we identified several subtypes of symbiotic interactions, as well as the characteristics that differentiate them, which we used to propose textual and axiomatic definitions for each subtype of interaction. To both illustrate how to use the ontological representations and definitions we created and provide additional quality assurance on key definitions, we carried out a referent tracking analysis and representation of three scenarios involving symbiotic interactions among organisms.

RESULTS: We found one definition of 'symbiosis' in an existing ontology that was consistent with the vast preponderance of scientific usage in biology and ecology. However, that ontology changed its definition during the course of our work, and discussions are ongoing. We present a new definition that we have proposed. We also define 34 subtypes of symbiosis. Our referent tracking analysis showed that it is necessary to define symbiotic interactions at the level of the individual, rather than at the species level, due to the complex nature in which organisms can go from participating in one type of symbiosis with one organism to participating in another type of symbiosis with a different organism.

CONCLUSION: As a result of our efforts here, we have developed a robust representation of symbiotic interactions using a realism-based approach, which fills a gap in existing biomedical ontologies.

RevDate: 2020-10-09

Mansour S, Swanson E, Pesce C, et al (2020)

Draft Genome Sequences for the Frankia sp. strains CgS1, CcI156 and CgMI4, Nitrogen-Fixing Bacteria Isolated from Casuarina sp. in Egypt.

Journal of genomics, 8:84-88.

Frankia sp. strains CgS1, CcI156 and CgMI4 were isolated from Casuarina glauca and C. cunninghamiana nodules. Here, we report the 5.26-, 5.33- and 5.20-Mbp draft genome sequences of Frankia sp. strains CgS1, CcI156 and CgMI4, respectively. Analysis of the genome revealed the presence of high numbers of secondary metabolic biosynthetic gene clusters.

RevDate: 2020-10-10

Jeon YJ, Gil CH, Won J, et al (2020)

Symbiotic microbiome Staphylococcus aureus from human nasal mucus modulates IL-33-mediated type 2 immune responses in allergic nasal mucosa.

BMC microbiology, 20(1):301.

BACKGROUND: The host-microbial commensalism can shape the innate immune responses in respiratory mucosa and nasal microbiome also modulates front-line immune mechanism in the nasal mucosa. Inhaled allergens encounter the host immune system first in the nasal mucosa, and microbial characteristics of nasal mucus directly impact the mechanisms of initial allergic responses in nasal epithelium. However, the roles of the nasal microbiome in allergic nasal mucosa remain uncertain. We sought to determine the distribution of nasal microbiomes in allergic nasal mucosa and elucidate the interplay between nasal microbiome Staphylococcus species and Th2 cytokines in allergic rhinitis (AR) models.

RESULTS: Staphylococcus aureus (AR-SA) and S. epidermidis (AR-SE) were isolated from the nasal mucosa of patients with AR. The influence of nasal microbiome Staphylococcus species on allergic nasal mucosa was also tested with in vitro and in vivo AR models. Pyrosequencing data showed that colonization by S. epidermidis and S. aureus was more dominant in nasal mucus of AR subjects. The mRNA and protein levels of IL-33 and TSLP were significantly higher in AR nasal epithelial (ARNE) cells which were cultured from nasal mucosa of AR subjects, and exposure of ARNE cells to AR-SA reduced IL-33 mRNA and secreted protein levels. Particularly, ovalbumin-driven AR mice inoculated with AR-SA by intranasal delivery exhibited significantly reduced IL-33 in their nasal mucosa. In the context of these results, allergic symptoms and Th2 cytokine levels were significantly downregulated after intranasal inoculation of AR-SA in vivo AR mice.

CONCLUSION: Colonization by Staphylococcus species was more dominant in allergic nasal mucosa, and nasal commensal S. aureus from subjects with AR mediates anti-allergic effects by modulating IL-33-dependent Th2 inflammation. The results demonstrate the role of host-bacterial commensalism in shaping human allergic inflammation.

RevDate: 2020-10-07

Clowez S, Renicke C, Pringle JR, et al (2020)

Impact of menthol on growth and photosynthetic function of Breviolum minutum (Dinoflagellata, Dinophyceae, Symbiodiniaceae) and interactions with its Aiptasia host.

Journal of phycology [Epub ahead of print].

Environmental change, including global warming and chemical pollution, can compromise cnidarian (e.g., coral) -dinoflagellate symbioses and cause coral bleaching. Understanding the mechanisms that regulate these symbioses will inform strategies for sustaining healthy coral-reef communities. A model system for corals is the symbiosis between the sea anemone Exaiptasia pallida (common name Aiptasia) and its dinoflagellate partners (family Symbiodiniaceae). To complement existing studies of the interactions between these organisms, we examined the impact of menthol, a reagent often used to render cnidarians aposymbiotic, on the dinoflagellate Breviolum minutum, both in culture and in hospite. In both environments, the growth and photosynthesis of this alga were compromised at either 100 or 300 µM menthol. We observed reduction of PSII and PSI functions, the abundances of reaction-center proteins, and, at 300 µM menthol, of total cellular proteins. Interestingly, for free-living algae exposed to 100 µM menthol, an initial decline in growth, photosynthetic activities, pigmentation, and protein abundances reversed after 5-15 d, eventually approaching control levels. This behavior was observed in cells maintained in continuous light, but not in cells experiencing a light-dark regimen, suggesting that B. minutum can detoxify menthol or acclimate and repair damaged photosynthetic complexes in a light- and/or energy-dependent manner. Extended exposures of cultured algae to 300 µM menthol ultimately resulted in algal death. Most symbiotic anemones were also unable to survive this menthol concentration for 30 d. Additionally, cells impaired for photosynthesis by pre-treatment with 300 µM menthol exhibited reduced efficiency in re-populating the anemone host.

RevDate: 2020-10-09

Majumder R, Sutcliffe B, Taylor PW, et al (2020)

Fruit host-dependent fungal communities in the microbiome of wild Queensland fruit fly larvae.

Scientific reports, 10(1):16550.

Bactrocera tryoni (Froggatt), the Queensland fruit fly (Qfly), is a highly polyphagous tephritid fly that is widespread in Eastern Australia. Qfly physiology is closely linked with its fungal associates, with particular relationship between Qfly nutrition and yeast or yeast-like fungi. Despite animal-associated fungi typically occurring in multi-species communities, Qfly studies have predominately involved the culture and characterisation of single fungal isolates. Further, only two studies have investigated the fungal communities associated with Qfly, and both have used culture-dependant techniques that overlook non-culturable fungi and hence under-represent, and provide a biased interpretation of, the overall fungal community. In order to explore a potentially hidden fungal diversity and complexity within the Qfly mycobiome, we used culture-independent, high-throughput Illumina sequencing techniques to comprehensively, and holistically characterized the fungal community of Qfly larvae and overcome the culture bias. We collected larvae from a range of fruit hosts along the east coast of Australia, and all had a mycobiome dominated by ascomycetes. The most abundant fungal taxa belonged to the genera Pichia (43%), Candida (20%), Hanseniaspora (10%), Zygosaccharomyces (11%) and Penicillium (7%). We also characterized the fungal communities of fruit hosts, and found a strong degree of overlap between larvae and fruit host communities, suggesting that these communities are intimately inter-connected. Our data suggests that larval fungal communities are acquired from surrounding fruit flesh. It is likely that the physiological benefits of Qfly exposure to fungal communities is primarily due to consumption of these fungi, not through syntrophy/symbiosis between fungi and insect 'host'.

RevDate: 2020-10-07

Motoki K, Watsuji TO, Takaki Y, et al (2020)

Metatranscriptomics by In Situ RNA Stabilization Directly and Comprehensively Revealed Episymbiotic Microbial Communities of Deep-Sea Squat Lobsters.

mSystems, 5(5):.

Shinkaia crosnieri is an invertebrate that inhabits an area around deep-sea hydrothermal vents in the Okinawa Trough in Japan by harboring episymbiotic microbes as the primary nutrition. To reveal physiology and phylogenetic composition of the active episymbiotic populations, metatranscriptomics is expected to be a powerful approach. However, this has been hindered by substantial perturbation (e.g., RNA degradation) during time-consuming retrieval from the deep sea. Here, we conducted direct metatranscriptomic analysis of S. crosnieri episymbionts by applying in situ RNA stabilization equipment. As expected, we obtained RNA expression profiles that were substantially different from those obtained by conventional metatranscriptomics (i.e., stabilization after retrieval). The episymbiotic community members were dominated by three orders, namely, Thiotrichales, Methylococcales, and Campylobacterales, and the Campylobacterales members were mostly dominated by the Sulfurovum genus. At a finer phylogenetic scale, the episymbiotic communities on different host individuals shared many species, indicating that the episymbionts on each host individual are not descendants of a few founder cells but are horizontally exchanged. Furthermore, our analysis revealed the key metabolisms of the community: two carbon fixation pathways, a formaldehyde assimilation pathway, and utilization of five electron donors (sulfide, thiosulfate, sulfur, methane, and ammonia) and two electron accepters (oxygen and nitrate/nitrite). Importantly, it was suggested that Thiotrichales episymbionts can utilize intercellular sulfur globules even when sulfur compounds are not usable, possibly also in a detached and free-living state.IMPORTANCE Deep-sea hydrothermal vent ecosystems remain mysterious. To depict in detail the enigmatic life of chemosynthetic microbes, which are key primary producers in these ecosystems, metatranscriptomic analysis is expected to be a promising approach. However, this has been hindered by substantial perturbation (e.g., RNA degradation) during time-consuming retrieval from the deep sea. In this study, we conducted direct metatranscriptome analysis of microbial episymbionts of deep-sea squat lobsters (Shinkaia crosnieri) by applying in situ RNA stabilization equipment. Compared to conventional metatranscriptomics (i.e., RNA stabilization after retrieval), our method provided substantially different RNA expression profiles. Moreover, we discovered that S. crosnieri and its episymbiotic microbes constitute complex and resilient ecosystems, where closely related but various episymbionts are stably maintained by horizontal exchange and partly by their sulfur storage ability for survival even when sulfur compounds are not usable, likely also in a detached and free-living state.

RevDate: 2020-10-07

Hague MTJ, Caldwell CN, BS Cooper (2020)

Pervasive Effects of Wolbachia on Host Temperature Preference.

mBio, 11(5):.

Heritable symbionts can modify a range of ecologically important host traits, including behavior. About half of all insect species are infected with maternally transmitted Wolbachia, a bacterial endosymbiont known to alter host reproduction, nutrient acquisition, and virus susceptibility. Here, we broadly test the hypothesis that Wolbachia modifies host behavior by assessing the effects of eight different Wolbachia strains on the temperature preference of six Drosophila melanogaster subgroup species. Four of the seven host genotypes infected with A-group Wolbachia strains (wRi in Drosophila simulans, wHa in D. simulans, wSh in Drosophila sechellia, and wTei in Drosophila teissieri) prefer significantly cooler temperatures relative to uninfected genotypes. Contrastingly, when infected with divergent B-group wMau, Drosophila mauritiana prefers a warmer temperature. For most strains, changes to host temperature preference do not alter Wolbachia titer. However, males infected with wSh and wTei tend to experience an increase in titer when shifted to a cooler temperature for 24 h, suggesting that Wolbachia-induced changes to host behavior may promote bacterial replication. Our results indicate that Wolbachia modifications to host temperature preference are likely widespread, which has important implications for insect thermoregulation and physiology. Understanding the fitness consequences of these Wolbachia effects is crucial for predicting evolutionary outcomes of host-symbiont interactions, including how Wolbachia spreads to become common.IMPORTANCE Microbes infect a diversity of species, influencing the performance and fitness of their hosts. Maternally transmitted Wolbachia bacteria infect most insects and other arthropods, making these bacteria some of the most common endosymbionts in nature. Despite their global prevalence, it remains mostly unknown how Wolbachia influence host physiology and behavior to proliferate. We demonstrate pervasive effects of Wolbachia on Drosophila temperature preference. Most hosts infected with A-group Wolbachia prefer cooler temperatures, whereas the one host species infected with divergent B-group Wolbachia prefers warmer temperatures, relative to uninfected genotypes. Changes to host temperature preference generally do not alter Wolbachia abundance in host tissues, but for some A-group strains, adult males have increased Wolbachia titer when shifted to a cooler temperature. This suggests that Wolbachia-induced changes to host behavior may promote bacterial replication. Our results help elucidate the impact of endosymbionts on their hosts amid the global Wolbachia pandemic.

RevDate: 2020-10-06

Sogin EM, Leisch N, N Dubilier (2020)

Chemosynthetic symbioses.

Current biology : CB, 30(19):R1137-R1142.

Symbioses between chemosynthetic bacteria and eukaryotic hosts can be found almost everywhere in the ocean, from shallow-water seagrass beds and coral reef sediments to the deep sea. Yet no one knew these existed until 45 years ago, when teeming communities of animals were found thriving at hydrothermal vents two and a half kilometers below the sea surface. The discovery of these lightless ecosystems revolutionized our understanding of the energy sources that fuel life on Earth. Animals thrive at vents because they live in a nutritional symbiosis with chemosynthetic bacteria that grow on chemical compounds gushing out of the vents, such as sulfide and methane, which animals cannot use on their own. The symbionts gain energy from the oxidation of these reduced substrates to fix CO2 and other simple carbon compounds into biomass, which is then transferred to the host. By associating with chemosynthetic bacteria, animals and protists can thrive in environments in which there is not enough organic carbon to support their nutrition, including oligotrophic habitats like coral reefs and seagrass meadows. Chemosymbioses have evolved repeatedly and independently in multiple lineages of marine invertebrates and bacteria, highlighting the strong selective advantage for both hosts and symbionts in forming these associations. Here, we provide a brief overview of chemosynthesis and how these symbioses function. We highlight some of the current research in this field and outline several promising avenues for future research.

RevDate: 2020-10-06

Perry BJ, Ferguson S, Laugraud A, et al (2020)

Complete Genome Sequences of Trifolium spp. Inoculant Strains Rhizobium leguminosarum symbiovar trifolii TA1 and CC275e: Resources for Genomic Study of the Rhizobium-Trifolium Symbiosis.

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

Rhizobium leguminosarum sv. trifolii strains TA1 and CC275e are nitrogen-fixing microsymbionts of Trifolium spp. and have been used as commercial inoculant strains for clovers in pastoral agriculture in Australia and New Zealand. Here we present the complete genome sequences of both strains, resolving their multipartite genome structures and allowing for future studies using genomic approaches.

RevDate: 2020-10-06

Shan H, Liu Y, Luan J, et al (2020)

New insights into the transovarial transmission of the symbiont Rickettsia in whiteflies.

Science China. Life sciences pii:10.1007/s11427-020-1801-7 [Epub ahead of print].

Endosymbiont transmission via eggs to future host generations has been recognized as the main strategy for its persistence in insect hosts; however, the mechanisms for transmission have yet to be elucidated. Here, we describe the dynamic locations of Rickettsia in the ovarioles and eggs during oogenesis and embryogenesis in a globally significant pest whitefly Bemisia tabaci. Field populations of the whitefly have a high prevalence of Rickettsia, and in all Rickettsia-infected individuals, the bacterium distributes in the body cavity of the host, especially in the midgut, fat body, hemocytes, hemolymph, and near bacteriocytes. The distribution of Rickettsia was subjected to dynamic changes in the ovary during oogenesis, and our ultrastructural observations indicated that the bacteria infect host ovarioles during early developmental stages via two routes: (i) invasion of the tropharium by endocytosis and then transmission into vitellarium via nutritive cord and (ii) entry into vitellarium by hijacking bacteriocyte translocation. Most of the Rickettsia are degraded in the oocyte cytoplasm in late-stage oogenesis. However, a few reside beneath the vitelline envelope of mature eggs, spread into the embryo, and proliferate during embryogenesis to sustain high-fidelity transmission to the next generation. Our findings provide novel insights into the maternal transmission underpinning the persistence and spread of insect symbionts.

RevDate: 2020-10-08
CmpDate: 2020-10-08

Müller LM (2020)

An Evolutionary Perspective on LysM Receptors Reveals Conserved Mechanisms for Microbial Signal Perception.

Plant physiology, 184(2):562-563.

RevDate: 2020-10-06

Sun G, Putkaradze N, Bohnacker S, et al (2020)

Six uridine-diphosphate glycosyltransferases catalyze the glycosylation of bioactive C13-apocarotenols.

Plant physiology pii:pp.20.00953 [Epub ahead of print].

C13-apocarotenoids (norisoprenoids) are carotenoid-derived oxidation products that perform important physiological functions in plants. Although their biosynthetic pathways have been extensively studied, their metabolism including glycosylation remains poorly understood. Candidate uridine-diphosphate glycosyltransferase genes (UGTs) were selected based on their high transcript abundance in comparison with other UGTs in vegetative tissues of Nicotiana benthamiana and peppermint (Mentha × piperita), as these tissues are rich sources of apocarotenoid glucosides. Hydroxylated C13-apocarotenol substrates were produced by P450-catalyzed biotransformation and microbial/plant enzyme systems were established for the synthesis of glycosides. Natural substrates were identified by physiological aglycone libraries prepared from isolated plant glycosides. In total, we identified six UGTs that catalyze the glucosylation of C13-apocarotenols, where glucose is bound either to the cyclohexene ring or butane side chain. MpUGT86C10 is a superior novel enzyme that catalyzes the glucosylation of allelopathic 3-hydroxy-α-damascone, 3-oxo-α-ionol, 3-oxo-7,8-dihydro-α-ionol (Blumenol C), and 3-hydroxy-7,8-dihydro-β-ionol, whereas a germination test demonstrated the higher phytotoxic potential of a norisoprenoid glucoside in comparison to its aglycone. Glycosylation of C13-apocarotenoids has several functions in plants, including increased allelopathic activity of the aglycone, facilitating exudation by roots and allowing symbiosis with arbuscular mycorrhizal fungi. The results enable in-depth analyses of the roles of glycosylated norisoprenoid allelochemicals, the physiological functions of apocarotenoids during arbuscular mycorrhizal colonization and the associated maintenance of carotenoid homeostasis.

RevDate: 2020-10-06
CmpDate: 2020-10-06

Geretharan T, Jeyakumar P, Bretherton M, et al (2020)

Fluorine and white clover: Assessing fluorine's impact on Rhizobium leguminosarum.

Journal of environmental quality, 49(4):987-999.

The soil fluorine (F) concentration in New Zealand agricultural soils has increased with time as a direct result of the widespread application of phosphate fertilizer to land. Elevated soil F concentrations may potentially harm soil microorganisms, which are important for nutrient cycling and soil formation. Rhizobium leguminosarum is a N2 -fixing soil bacterium that is a fundamental component in New Zealand legume-based pastoral farming. Any impact of F on Rhizobium leguminosarum would have an adverse effect on New Zealand pasture production. In this study, F toxicity to Rhizobium leguminosarum was examined as a first step to develop F guideline values for New Zealand agricultural soils. Bottle-based experiments were conducted to examine the effect of the F- ion on Rhizobium-white clover (Trifolium repens L.) symbiosis by observing nodule morphology and growth. Results indicate that the F- concentration that causes 10% inhibition of Rhizobium respiration (IC10) for F- toxicity to Rhizobium leguminosarum was >100 mg F- L-1 . Significant morphological changes occurred when Rhizobium was exposed to F concentrations of 500 and 1000 mg L-1 . Both light and transmission electron micrographs confirmed that the Rhizobium leguminosarum-white clover interaction was not influenced by F- concentrations >100 mg L-1 . The toxic F- concentration for Rhizobium leguminosarum determined in this study is orders of magnitude higher than the F- concentration in New Zealand agriculture soils under "normal conditions." There appears to be no indication of imminent risk of soil F to Rhizobium leguminosarum.


ESP Quick Facts

ESP Origins

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

ESP Support

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

ESP Rationale

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

ESP Goal

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

ESP Usage

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

ESP Content

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

ESP Help

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

ESP Plans

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

Electronic Scholarly Publishing
961 Red Tail Lane
Bellingham, WA 98226

E-mail: RJR8222 @

Papers in Classical Genetics

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

Digital Books

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


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


Biographical information about many key scientists.

Selected Bibliographies

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

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