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Bibliography on: Symbiosis

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Robert J. Robbins is a biologist, an educator, a science administrator, a publisher, an information technologist, and an IT leader and manager who specializes in advancing biomedical knowledge and supporting education through the application of information technology. More About:  RJR | OUR TEAM | OUR SERVICES | THIS WEBSITE

RJR: Recommended Bibliography 12 Jul 2020 at 01:47 Created: 

Symbiosis

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®)

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RevDate: 2020-07-11

Ferguson S, Major AS, Sullivan JT, et al (2020)

Rhizobium leguminosarum bv. trifolii NodD2 enhances competitive nodule colonisation in the clover-rhizobium symbiosis.

Applied and environmental microbiology pii:AEM.01268-20 [Epub ahead of print].

Establishment of the symbiotic relationship that develops between rhizobia and their legume hosts is contingent upon an interkingdom signal exchange. In response to host legume flavonoids, NodD proteins from compatible rhizobia activate expression of nodulation (nod) genes that produce lipochitin oligosaccharide signalling molecules known as Nod factors. Root nodule formation commences upon legume recognition of compatible Nod factor. Rhizobium leguminosarum was previously considered to contain one copy of nodD; here we show that some strains of the Trifolium (clover) microsymbiont R. leguminosarum bv. trifolii (Rlt) contain a second copy designated nodD2. nodD2 genes were present in eight out of 13 strains of Rlt interrogated but were absent from the genomes of 16 R. leguminosarum bv. viciae strains. Analysis of single and double nodD1 and nodD2 mutants in Rlt strain TA1 revealed that NodD2 was functional and enhanced nodule colonisation competitiveness. However, NodD1 showed significantly greater capacity to induce nod gene expression and infection thread (IT) formation. Clover species are either annual or perennial and this phenological distinction is rarely crossed by individual Rlt microsymbionts for effective symbiosis. Of 13 strains with genome sequences available, seven of the eight effective microsymbionts of perennial hosts contained nodD2 whereas the three microsymbionts of annual hosts did not. We hypothesise that NodD2 inducer recognition differs from NodD1, and NodD2 functions to enhance competition and effective symbiosis, which may discriminate in favour of perennial hosts.IMPORTANCE Establishment of the rhizobium-legume symbiosis requires a highly specific and complex signal exchange between both participants. Rhizobia perceive legume flavonoid compounds through LysR-type NodD regulators. Often, rhizobia encode multiple copies of nodD, which is one determinant of host specificity. In some species of rhizobia, the presence of multiple copies of NodD extends their symbiotic host-range. Here we identified and characterised a second copy of nodD present in some strains of the clover microsymbiont Rhizobium leguminosarum bv. trifolii The second nodD gene contributed to the competitive ability of the strain on white clover, an important forage legume. A screen for strains containing nodD2 could be utilised as one criterion to select strains with enhanced competitive ability for use as inoculants for pasture production.

RevDate: 2020-07-11

Lunge A, Gupta R, Choudhary E, et al (2020)

The unfoldase ClpC1 of Mycobacterium tuberculosis regulates the expression of a distinct subset of proteins having intrinsically disordered termini.

The Journal of biological chemistry, 295(28):9455-9473.

The human pathogen Mycobacterium tuberculosis (Mtb) harbors a well-orchestrated Clp (caseinolytic protease) proteolytic machinery consisting of two oligomeric segments, a barrel-shaped heterotetradecameric protease core comprising the ClpP1 and ClpP2 subunits, and hexameric ring-like ATP-dependent unfoldases composed of ClpX or ClpC1. The roles of the ClpP1P2 protease subunits are well-established in Mtb, but the potential roles of the associated unfoldases, such as ClpC1, remain elusive. Using a CRISPR interference-mediated gene silencing approach, here we demonstrate that clpC1 is indispensable for the extracellular growth of Mtb and for its survival in macrophages. The results from isobaric tags for relative and absolute quantitation-based quantitative proteomic experiments with clpC1- and clpP2-depleted Mtb cells suggested that the ClpC1P1P2 complex critically maintains the homeostasis of various growth-essential proteins in Mtb, several of which contain intrinsically disordered regions at their termini. We show that the Clp machinery regulates dosage-sensitive proteins such as the small heat shock protein Hsp20, which exists in a dodecameric conformation. Further, we observed that Hsp20 is poorly expressed in WT Mtb and that its expression is greatly induced upon depletion of clpC1 or clpP2 Remarkably, high Hsp20 protein levels were detected in the clpC1(-) or clpP2(-) knockdown strains but not in the parental bacteria, despite significant induction of hsp20 transcripts. In summary, the cellular levels of oligomeric proteins such as Hsp20 are maintained post-translationally through their recognition, disassembly, and degradation by ClpC1, which requires disordered ends in its protein substrates.

RevDate: 2020-07-10

Nguyen TT, Nguyen TT, An Binh Q, et al (2020)

Co-culture of microalgae-activated sludge for wastewater treatment and biomass production: Exploring their role under different inoculation ratios.

Bioresource technology, 314:123754 pii:S0960-8524(20)31026-9 [Epub ahead of print].

In this study, mixed culture (microalgae:activated sludge) of a photobioreactor (PBR) were investigated at different inoculation ratios (1:0, 9:1, 3:1, 1:1, 0:1 wt/wt). This work was not only to determine the optimal ratio for pollutant remediation and biomass production but also to explore the role of microorganisms in the co-culture system. The results showed high total biomass concentrations were obtained from 1:0 and 3:1 ratio being values of 1.06, 1.12 g L-1, respectively. Microalgae played a dominant role in nitrogen removal via biological assimilation while activated sludge was responsible for improving COD removal. Compared with the single culture of microalgae, the symbiosis between microalgae and bacteria occurred at 3:1 and 1:1 ratio facilitated a higher COD removal by 37.5-45.7 %. In general, combined assessment based on treatment performance and biomass productivity facilitated to select an optimal ratio of 3:1 for the operation of the co-culture PBR.

RevDate: 2020-07-10

Jannat MAH, Lee J, Shin SG, et al (2020)

Long-term enrichment of anaerobic propionate-oxidizing consortia: Syntrophic culture development and growth optimization.

Journal of hazardous materials, 401:123230 pii:S0304-3894(20)31219-X [Epub ahead of print].

Propionate is a quantitatively important methanogenic intermediate in anaerobic digesters and only limited number of microbes can utilize it under syntrophic association with methanogens. The syntrophic propionate oxidizing bacterias are known to be slow growers due to the low energy yield. Thus, propionate get accumulated frequently in anaerobic digesters and it negatively affect digester performance. In this study, propionate degrading consortia from four different seeding sources were enriched in sequential bath mode in two phases; first adaption phase with 1 g/L of propionate concentration and later, high-strength phase with 3 g/L. From 16s rRNA gene based metagenomics analysis of the former phase, four syntrophic microbial groups, Syntrophaceae, Syntrophomonadaceae, Methanobacterium and Methanosaeta were found to be dominant with complete degradation of propionate. The substrate accelerated microbial shifts were observed at high-strength phase with significant decrease of Syntrophaceae up to 26.9 %. Using Response Surface Methodology, pH 6.8-6.9 and temperature 34.5-34.9 °C were found to be optimum growth conditions for the propionate degradation culture. Observed results could be useful to improve degradation efficiencies and obtained enriched culture can be used to recover propionate-accumulated digesters by bio-augmentation.

RevDate: 2020-07-10

Behr M, Baldacci-Cresp F, Kohler A, et al (2020)

Alterations in the phenylpropanoid pathway affect poplar ability for ectomycorrhizal colonisation and susceptibility to root-knot nematodes.

Mycorrhiza pii:10.1007/s00572-020-00976-6 [Epub ahead of print].

This study investigates the impact of the alteration of the monolignol biosynthesis pathway on the establishment of the in vitro interaction of poplar roots either with a mutualistic ectomycorrhizal fungus or with a pathogenic root-knot nematode. Overall, the five studied transgenic lines downregulated for caffeoyl-CoA O-methyltransferase (CCoAOMT), caffeic acid O-methyltransferase (COMT), cinnamoyl-CoA reductase (CCR), cinnamyl alcohol dehydrogenase (CAD) or both COMT and CAD displayed a lower mycorrhizal colonisation percentage, indicating a lower ability for establishing mutualistic interaction than the wild-type. The susceptibility to root-knot nematode infection was variable in the five lines, and the CAD-deficient line was found to be less susceptible than the wild-type. We discuss these phenotypic differences in the light of the large shifts in the metabolic profile and gene expression pattern occurring between roots of the CAD-deficient line and wild-type. A role of genes related to trehalose metabolism, phytohormones, and cell wall construction in the different mycorrhizal symbiosis efficiency and nematode sensitivity between these two lines is suggested. Overall, these results show that the alteration of plant metabolism caused by the repression of a single gene within phenylpropanoid pathway results in significant alterations, at the root level, in the response towards mutualistic and pathogenic associates. These changes may constrain plant fitness and biomass production, which are of economic importance for perennial industrial crops such as poplar.

RevDate: 2020-07-10

Wiley CA (2020)

Emergent Viral Infections of the CNS.

Journal of neuropathology and experimental neurology pii:5869577 [Epub ahead of print].

Biological evolution of the microbiome continually drives the emergence of human viral pathogens, a subset of which attack the nervous system. The sheer number of pathogens that have appeared, along with their abundance in the environment, demand our attention. For the most part, our innate and adaptive immune systems have successfully protected us from infection; however, in the past 5 decades, through pathogen mutation and ecosystem disruption, a dozen viruses emerged to cause significant neurologic disease. Most of these pathogens have come from sylvatic reservoirs having made the energetically difficult, and fortuitously rare, jump into humans. But the human microbiome is also replete with agents already adapted to the host that need only minor mutations to create neurotropic/toxic agents. While each host/virus symbiosis is unique, this review examines virologic and immunologic principles that govern the pathogenesis of different viral CNS infections that were described in the past 50 years (Influenza, West Nile Virus, Zika, Rift Valley Fever Virus, Hendra/Nipah, Enterovirus-A71/-D68, Human parechovirus, HIV, and SARS-CoV). Knowledge of these pathogens provides us the opportunity to respond and mitigate infection while at the same time prepare for inevitable arrival of unknown agents.

RevDate: 2020-07-10

Fan Y, Wang X, Li H, et al (2020)

Anthocyanin, a novel and user-friendly reporter for convenient, non-destructive, low cost, directly visual selection of transgenic hairy roots in the study of rhizobia-legume symbiosis.

Plant methods, 16:94 pii:638.

Background: Agrobacterium rhizogenes-mediated hairy root transformation provides a powerful tool for investigating the functions of plant genes involved in rhizobia-legume symbiosis. However, in the traditional identification methods of transgenic hairy roots based on reporter genes, an expensive chemical substrate or equipment is required.

Results: Here, we report a novel, low cost, and robust reporter for convenient, non-destructive, and directly visual selection of transgenic hairy roots by naked eye, which can be used in the study of rhizobia-legume symbiosis. The reporter gene AtMyb75 in Arabidopsis, encoding an R2R3 type MYB transcription factor, was ectopically expressed in hairy roots-mediated by A. rhizogenes, which induced purple/red colored anthocyanin accumulation in crop species like soybean (Glycine max (L.) Merr.) and two model legume species, Lotus japonicas and Medicago truncatula. Transgenic hairy roots of legumes containing anthocyanin can establish effective symbiosis with rhizobia. We also demonstrated the reliability of AtMyb75 as a reporter gene by CRISPR/Cas9-targeted mutagenesis of the soybean resistance to nodulation Rfg1 gene in the soybean PI377578 (Nod-) inoculated with Sinorhizobium fredii USDA193. Without exception, mature nitrogen-fixation nodules, were formed on purple transgenic hairy roots containing anthocyanin.

Conclusions: Anthocyanin is a reliable, user-friendly, convenient, non-destructive, low cost, directly visual reporter for studying symbiotic nitrogen-fixing nodule development and could be widely applied in broad leguminous plants.

RevDate: 2020-07-10

He C, Wang W, J Hou (2020)

Plant performance of enhancing licorice with dual inoculating dark septate endophytes and Trichoderma viride mediated via effects on root development.

BMC plant biology, 20(1):325 pii:10.1186/s12870-020-02535-9.

BACKGROUND: This study aimed to assess whether licorice (Glycyrrhiza uralensis) can benefit from dual inoculation by Trichoderma viride and dark septate endophytes (DSE) isolated from other medicinal plants.

METHODS: First, we isolated and identified three DSE (Paraboeremia putaminum, Scytalidium lignicola, and Phoma herbarum) and Trichoderma viride from medicinal plants growing in farmland of China. Second, we investigated the influences of these three DSE on the performance of licorice at different T. viride densities (1 × 106, 1 × 107, and 1 × 108 CFU/mL) under sterilised condition in a growth chamber.

RESULTS: Three DSE strains could colonize the roots of licorice, and they established a positive symbiosis with host plants depending on DSE species and T. viride densities. Inoculation of P. putaminum increased the root biomass, length, surface area, and root:shoot ratio. S. lignicola increased the root length, diameter and surface area and decreased the root:shoot ratio. P. herbarum increased the root biomass and surface area. T. viride increased the root biomass, length, and surface area. Structural equation model (SEM) analysis showed that DSE associated with T. viride augmented plant biomass and height, shoot branching, and root surface area. Variations in root morphology and biomass were attributed to differences in DSE species and T. viride density among treatments. P. putaminum or P. herbarum with low- or medium T. viride density and S. lignicola with low- or high T. viride density improved licorice root morphology and biomass.

CONCLUSIONS: DSE isolated from other medicinal plants enhanced the root growth of licorice plants under different densities T. viride conditions and may also be used to promote the cultivation of medicinal plants.

RevDate: 2020-07-10
CmpDate: 2020-07-10

Yu X, Yu K, Huang W, et al (2020)

Thermal acclimation increases heat tolerance of the scleractinian coral Acropora pruinosa.

The Science of the total environment, 733:139319.

Field ecological observations indicate that scleractinian coral exposed to early thermal stress are likely to develop higher tolerance to subsequent heat stress. The causes of this phenomenon, however, remain enigmatic. To unravel the mechanisms underlying the increased heat tolerance, we applied different thermal treatments to the scleractinian coral Acropora pruinosa and studied the resulting differences in appearance, physiological index, Symbiodiniaceae and bacterial communities, and transcriptome response. We found that early heat stress improved the thermal tolerance of the coral holobiont. After thermal acclimation, the community structure and symbiotic bacterial diversity in the microbiota were reorganized, whereas those of Symbiodiniaceae remained stable. RNA-seq analysis revealed that the downregulated coral host genes were mainly involved in pathways relating to metabolism, particularly the nitrogen metabolism pathway. This indicates that thermal acclimation led to decrease in the metabolism level in the coral host, which might be a self-protection mechanism. We suggest that thermal acclimation may increase scleractinian coral thermal tolerance by slowing host metabolism, altering the dominant bacterial population, and increasing bacterial diversity. This study offers new insights into the adaptive potential of scleractinian coral to heat stress from global warming.

RevDate: 2020-07-10
CmpDate: 2020-07-10

Lanctôt CM, Bednarz VN, Melvin S, et al (2020)

Physiological stress response of the scleractinian coral Stylophora pistillata exposed to polyethylene microplastics.

Environmental pollution (Barking, Essex : 1987), 263(Pt A):114559.

We investigated physiological responses including calcification, photosynthesis and alterations to polar metabolites, in the scleractinian coral Stylophora pistillata exposed to different concentrations of polyethylene microplastics. Results showed that at high plastic concentrations (50 particles/mL nominal concentration) the photosynthetic efficiency of photosystem II in the coral symbiont was affected after 4 weeks of exposure. Both moderate and high (5 and 50 particles/mL nominal) concentrations of microplastics caused subtle but significant alterations to metabolite profiles of coral, as determined by Nuclear Magnetic Resonance (NMR) spectroscopy. Specifically, exposed corals were found to have increased levels of phosphorylated sugars and pyrimidine nucleobases that make up nucleotides, scyllo-inositol and a region containing overlapping proline and glutamate signals, compared to control animals. Together with the photo-physiological stress response observed and previously published literature, these findings support the hypothesis that microplastics disrupt host-symbiont signaling and that corals respond to this interference by increasing signaling and chemical support to the symbiotic zooxanthellae algae. These findings are also consistent with increased mucus production in corals exposed to microplastics described in previous studies. Considering the importance of coral reefs to marine ecosystems and their sensitivity to anthropogenic stressors, more research is needed to elucidate coral response mechanisms to microplastics under realistic exposure conditions.

RevDate: 2020-07-10
CmpDate: 2020-07-10

Melo CR, Oliveira BMS, Santos ACC, et al (2020)

Synergistic effect of aromatic plant essential oils on the ant Acromyrmex balzani (Hymenoptera: Formicidae) and antifungal activity on its symbiotic fungus Leucoagaricus gongylophorus (Agaricales: Agaricaceae).

Environmental science and pollution research international, 27(14):17303-17313.

Leaf-cutting ants have great potential for damage to agricultural and forest crops. Although chemical control is the most used method for the management of this pest, more friendly alternative methods have been investigated. Thus, this study aimed to evaluate the insecticidal and antifungal potential of essential oils obtained from Aristolochia trilobata, as well as the potential of two chemotypes of Myrcia lundiana and their major compounds (isopulegol and citral) on Acromyrmex balzani and its symbiotic fungus Leucoagaricus gongylophorus. Toxicity and synergism and/or antagonism tests were performed using essential oils and their major compounds on A. balzani ants. The antifungal activity of these compounds was tested on the fungus L. gongylophorus. The essential oils and their major compounds were toxic to A. balzani. The mixture of essential oils of A. trilobata with those of M. lundiana had higher toxicity to the ants. This synergistic effect is mainly due to the interactions between the citral compound and the major compounds present in A. trilobata essential oil. The essential oils of M. lundiana chemotypes showed antifungal properties against L. gongylophorus, and the citral compound proved to have fungicidal activity. These results show that the use of M. lundiana and A. trilobata essential oils and their major compounds is a potential alternative for the management of leaf-cutting ants A. balzani, as they have a toxic effect on worker ants and antifungal activity on their symbiotic fungus.

RevDate: 2020-07-10
CmpDate: 2020-07-10

Sommariva M, Le Noci V, Bianchi F, et al (2020)

The lung microbiota: role in maintaining pulmonary immune homeostasis and its implications in cancer development and therapy.

Cellular and molecular life sciences : CMLS, 77(14):2739-2749.

Like other body districts, lungs present a complex bacteria community. An emerging function of lung microbiota is to promote and maintain a state of immune tolerance, to prevent uncontrolled and not desirable inflammatory response caused by inhalation of harmless environmental stimuli. This effect is mediated by a continuous dialog between commensal bacteria and immune cells resident in lungs, which express a repertoire of sensors able to detect microorganisms. The same receptors are also involved in the recognition of pathogens and in mounting a proper immune response. Due to its important role in preserving lung homeostasis, the lung microbiota can be also considered a mirror of lung health status. Indeed, several studies indicate that lung bacterial composition drastically changes during the occurrence of pulmonary pathologies, such as lung cancer, and the available data suggest that the modifications of lung microbiota can be part of the etiology of tumors in lungs and can influence their progression and response to therapy. These results provide the scientific rationale to analyze lung microbiota composition as biomarker for lung cancer and to consider lung microbiota a new potential target for therapeutic intervention to reprogram the antitumor immune microenvironment. In the present review, we discussed about the role of lung microbiota in lung physiology and summarized the most relevant data about the relationship between lung microbiota and cancer.

RevDate: 2020-07-09

He C, C Zhu (2020)

Nesting and foraging behavior of Xylocopa valga in the Ejina Oasis, China.

PloS one, 15(7):e0235769 pii:PONE-D-20-02490.

Xylocopa valga is extinct in Latvia and Lithuania and is critically endangered in Poland, and its distribution in the Ejina Oasis, China, is currently unknown. Studies on the biology of X. valga are scarce, and thus, conservation efforts for this species are currently limited. Here, we investigated the morphological characteristics, nest architecture, nest structure and food type of offspring in the nest cells of X. valga. This research was conducted in the Populus euphratica forest reserve in the Ejina Oasis, China, between July 2014 and June 2019. The primary investigation methods included visual inspection, photography, observation and measurements of nest anatomy, and examination of pollen stores by microscopy. We found that in the Ejina Oasis, China, X. valga builds its nests in the dead wood of P. euphratica. X. valga is univoltine. Its lifestyle varies from solitude to symbiosis. When many females nest near each other, several females may share a single nest entrance, based on which they build their own cells. The nests are branched. According to our results, there is a significant difference between the thickness of the inner cell partition and that of the outermost cell partition in the branched tunnel. In the P. euphratica forest area, the food for the progeny of X. valga is mainly composed of the pollen and nectar of Sophora alopecuroide and Populus euphratica. Therefore, X. valga and S. alopecuroides exhibit close ecological interactions in the P. euphratica forest ecosystem.

RevDate: 2020-07-09

Sun K, Zhang W, Yuan J, et al (2020)

Nitrogen fertilizer-regulated plant-fungi interaction is related to root invertase-induced hexose generation.

FEMS microbiology ecology pii:5869223 [Epub ahead of print].

The mechanisms underlying nitrogen (N)-regulated plant-fungi interactions are not well understood. N application modulates plant carbohydrate (C) sinks and is involved in the overall plant-fungal association. We hypothesized that N regulates plant-fungi interactions by influencing the carbohydrate metabolism. The mutualistic fungus Phomopsis liquidambaris was found to prioritize host hexose resources through in vitro culture assays and in planta inoculation. Rice-Ph. liquidambaris systems were exposed to N gradients ranging from N-deficient to N-abundant conditions to study whether and how the sugar composition was involved in the dynamics of N-mediated fungal colonization. We found that root soluble acid invertases were activated, resulting in increased hexose fluxes in inoculated roots. These fluxes positively influenced fungal colonization, especially under N-deficient conditions. Further experiments manipulating the carbohydrate composition and root invertase activity through sugar feeding, chemical treatments, and the use of different soil types revealed that the external disturbance of root invertase could reduce endophytic colonization and eliminate endophyte-induced host benefits under N-deficient conditions. Collectively, these results suggest that the activation of root invertase is related to N deficiency-enhanced endophytic colonization via increased hexose generation. Certain combinations of farmland ecosystems with suitable N inputs could be implemented to maximize the benefits of plant-fungi associations.

RevDate: 2020-07-09
CmpDate: 2020-07-09

Vikuk V, Young CA, Lee ST, et al (2019)

Infection Rates and Alkaloid Patterns of Different Grass Species with Systemic Epichloë Endophytes.

Applied and environmental microbiology, 85(17):.

Symbiotic Epichloë species are fungal endophytes of cool-season grasses that can produce alkaloids with toxicity to vertebrates and/or invertebrates. Monitoring infections and presence of alkaloids in grasses infected with Epichloë species can provide an estimate of possible intoxication risks for livestock. We sampled 3,046 individuals of 13 different grass species in three regions on 150 study sites in Germany. We determined infection rates and used PCR to identify Epichloë species diversity based on the presence of different alkaloid biosynthesis genes, then confirmed the possible chemotypes with high-performance liquid chromatography (HPLC)/ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) measurements. Infections of Epichloë spp. were found in Festuca pratensis Huds. (81%), Festuca ovina L. aggregate (agg.) (73%), Lolium perenne L. (15%), Festuca rubra L. (15%) and Dactylis glomerata L. (8%). The other eight grass species did not appear to be infected. For the majority of Epichloë-infected L. perenne samples (98%), the alkaloids lolitrem B and peramine were present, but ergovaline was not detected, which was consistent with the genetic evaluation, as dmaW, the gene encoding the first step of the ergot alkaloid biosynthesis pathway, was absent. Epichloë uncinata in F. pratensis produced anti-insect loline compounds. The Epichloë spp. observed in the F. ovina agg. samples showed the greatest level of diversity, and different intermediates of the indole-diterpene pathway could be detected. Epichloë infection rates alone are insufficient to estimate intoxication risks for livestock, as other factors, like the ability of the endophyte to produce the alkaloids, also need to be assessed.IMPORTANCE Severe problems of livestock intoxication from Epichloë-infected forage grasses have been reported from New Zealand, Australia, and the United States, but much less frequently from Europe, and particularly not from Germany. Nevertheless, it is important to monitor infection rates and alkaloids of grasses with Epichloë fungi to estimate possible intoxication risks. Most studies focus on agricultural grass species like Lolium perenne and Festuca arundinacea, but other cool-season grass species can also be infected. We show that in Germany, infection rates and alkaloids differ between grass species and that some of the alkaloids can be toxic to livestock. Changes in grassland management due to changing climate, especially with a shift toward grasslands dominated with Epichloë-infected species such as Lolium perenne, may result in greater numbers of intoxicated livestock in the near future. We therefore suggest regular monitoring of grass species for infections and alkaloids and call for maintaining heterogenous grasslands for livestock.

RevDate: 2020-07-08

Satani H, Kuwata M, A Shimizu (2020)

Simple and environmentally friendly preparation of cellulose hydrogels using an ionic liquid.

Carbohydrate research, 494:108054 pii:S0008-6215(20)30009-4 [Epub ahead of print].

In this study, we developed an easy process for the production of cellulose hydrogels over a wide concentration range by using an ionic liquid/DMSO mixed solution that can easily be recycled at room temperature and has low environmental impact. Cellulose was completely dissolved at 6 to 20 wt% with respect to the [BMIm][OAc]/DMSO mixed solution at room temperature and ambient pressure. Placing the cellulose solution in a mold and immersing it in deionized water caused solvent replacement of the [BMIm][OAc]/DMSO mixed solution with deionized water, making it easy to obtain a cellulose hydrogel without using a crosslinking agent. Approximately 80% of the ionic liquid could be reused by constructing a system that recovers the ionic liquid discharged from the cellulose solution during solvent replacement. The pore size, water content and mechanical strength of the cellulose hydrogel strongly depended on the concentration of the cellulose solution prepared using the [BMIm][OAc]/DMSO mixture. However, the crystallinity and thermal stability did not show a concentration dependence.

RevDate: 2020-07-08

Li F, MC Simon (2020)

Cancer Cells Don't Live Alone: Metabolic Communication within Tumor Microenvironments.

Developmental cell pii:S1534-5807(20)30497-4 [Epub ahead of print].

Solid tumors reside in harsh tumor microenvironments (TMEs) together with various stromal cell types. During tumor progression and metastasis, both tumor and stromal cells undergo rapid metabolic adaptations. Tumor cells metabolically coordinate or compete with their "neighbors" to maintain biosynthetic and bioenergetic demands while escaping immunosurveillance or therapeutic interventions. Here, we provide an update on metabolic communication between tumor cells and heterogeneous stromal components in primary and metastatic TMEs and discuss emerging strategies to target metabolic communications for improved cancer treatments.

RevDate: 2020-07-08

Tran KN, Pham N, Jang SH, et al (2020)

Purification and characterization of a novel medium-chain ribitol dehydrogenase from a lichen-associated bacterium Sphingomonas sp.

PloS one, 15(7):e0235718 pii:PONE-D-20-11764.

Sugar alcohols (polyols) are abundant carbohydrates in lichen-forming algae and transported to other lichen symbionts, fungi, and bacteria. Particularly, ribitol is an abundant polyol in the lichen Cetraria sp. Polyols have important physiological roles in lichen symbiosis, but polyol utilization in lichen-associated bacteria has been largely unreported. Herein, we purified and characterized a novel ribitol dehydrogenase (RDH) from a Cetraria sp.-associated bacterium Sphingomonas sp. PAMC 26621 grown on a minimal medium containing D-ribitol (the RDH hereafter referred to as SpRDH). SpRDH is present as a trimer in its native form, and the molecular weight of SpRDH was estimated to be 39 kDa by SDS-PAGE and 117 kDa by gel filtration chromatography. SpRDH converted D-ribitol to D-ribulose using NAD+ as a cofactor. As far as we know, SpRDH is the first RDH belonging to the medium-chain dehydrogenase/reductase family. Multiple sequence alignments indicated that the catalytic amino acid residues of SpRDH consist of Cys37, His65, Glu66, and Glu157, whereas those of short-chain RDHs consist of Ser, Tyr, and Lys. Furthermore, unlike other short-chain RDHs, SpRDH did not require divalent metal ions for its catalytic activity. Despite SpRDH originating from a psychrophilic Arctic bacterium, Sphingomonas sp., it had maximum activity at 60°C and exhibited high thermal stability within the 4-50°C range. Further studies on the structure/function relationship and catalytic mechanism of SpRDH will expand our understanding of its role in lichen symbiosis.

RevDate: 2020-07-08

Ingraffia R, Amato G, Sosa-Hernández MA, et al (2020)

Nitrogen Type and Availability Drive Mycorrhizal Effects on Wheat Performance, Nitrogen Uptake and Recovery, and Production Sustainability.

Frontiers in plant science, 11:760.

Plant performance is strongly dependent on nitrogen (N), and thus increasing N nutrition is of great relevance for the productivity of agroecosystems. The effects of arbuscular mycorrhizal (AM) fungi on plant N acquisition are debated because contradictory results have been reported. Using 15N-labeled fertilizers as a tracer, we evaluated the effects of AM fungi on N uptake and recovery from mineral or organic sources in durum wheat. Under sufficient N availability, AM fungi had no effects on plant biomass but increased N concentrations in plant tissue, plant N uptake, and total N recovered from the fertilizer. In N-deficient soil, AM fungi led to decreased aboveground biomass, which suggests that plants and AM fungi may have competed for N. When the organic source had a low C:N ratio, AM fungi favored both plant N uptake and N recovery. In contrast, when the organic source had a high C:N ratio, a clear reduction in N recovery from the fertilizer was observed. Overall, the results indicate an active role of arbuscular mycorrhizae in favoring plant N-related traits when N is not a limiting factor and show that these fungi help in N recovery from the fertilizer. These results hold great potential for increasing the sustainability of durum wheat production.

RevDate: 2020-07-08

Ravenscraft A, Thairu MW, Hansen AK, et al (2020)

Continent-Scale Sampling Reveals Fine-Scale Turnover in a Beneficial Bug Symbiont.

Frontiers in microbiology, 11:1276.

Many members of animal-associated microbial communities, including the gut flora, are acquired from their host's environment. While many of these communities are species rich, some true bugs (Hemiptera) in the superfamilies Lygaeoidea and Coreidae allow only ingested Burkholderia to colonize and reproduce in a large portion of the midgut. We studied the spatial structuring of Burkholderia associated with a widespread omnivorous bug genus, Jalysus (Berytidae). We sampled Wickham's stilt bug, Jalysus wickhami, across the United States and performed limited sampling of its sister species, the spined stilt bug Jalysus spinosus. We asked: (1) What Burkholderia strains are hosted by Jalysus at different locations? (2) Does host insect species, host plant species, or location influence the strain these insects acquire? (3) How does Burkholderia affect the development and reproductive fitness of J. wickhami? We found: (1) Sixty-one Burkholderia strains were present across a sample of 352 individuals, but one strain dominated, accounting for almost half of all symbiont reads. Most strains were closely related to other hemipteran Burkholderia symbionts. (2) Many individuals hosted more than one strain of Burkholderia. (3) J. wickhami and J. spinosus did not differ in the strains they hosted. (4) Insects that fed on different plant species tended to host different Burkholderia, but this accounted for only 4% of the variation in strains hosted. In contrast, the location at which an insect was collected explained 27% of the variation in symbiont strains. (5) Burkholderia confers important fitness benefits to J. wickhami. In laboratory experiments, aposymbiotic (Burkholderia-free) insects developed more slowly and laid fewer eggs than symbiotic (Burkholderia-colonized) insects. (6) In the lab, nymphs sometimes acquired Burkholderia via indirect exposure to adults, indicating that horizontal symbiont transmission can occur via adult insect-mediated enrichment of Burkholderia in the local environment - a phenomenon not previously reported in bug-Burkholderia relationships. Taken together, the results suggest that for these bugs, critical nutritional requirements are outsourced to a highly diverse and spatially structured collection of Burkholderia strains acquired from the environment and, occasionally, from conspecific adults.

RevDate: 2020-07-08

Uchiumi Y, A Sasaki (2020)

Evolution of division of labour in mutualistic symbiosis.

Proceedings. Biological sciences, 287(1930):20200669.

Mutualistic symbiosis can be regarded as interspecific division of labour, which can improve the productivity of metabolites and services but deteriorate the ability to live without partners. Interestingly, even in environmentally acquired symbiosis, involved species often rely exclusively on the partners despite the lethal risk of missing partners. To examine this paradoxical evolution, we explored the coevolutionary dynamics in symbiotic species for the amount of investment in producing their essential metabolites, which symbiotic species can share. Our study has shown that, even if obtaining partners is difficult, 'perfect division of labour' (PDL) can be maintained evolutionarily, where each species perfectly specializes in producing one of the essential metabolites so that every member entirely depends on the others for survival, i.e. in exchange for losing the ability of living alone. Moreover, the coevolutionary dynamics shows multistability with other states including a state without any specialization. It can cause evolutionary hysteresis: once PDL has been achieved evolutionarily when obtaining partners was relatively easy, it is not reverted even if obtaining partners becomes difficult later. Our study suggests that obligate mutualism with a high degree of mutual specialization can evolve and be maintained easier than previously thought.

RevDate: 2020-07-08

Takeshita K, Y Kikuchi (2020)

Genomic Comparison of Insect Gut Symbionts from Divergent Burkholderia Subclades.

Genes, 11(7): pii:genes11070744.

Stink bugs of the superfamilies Coreoidea and Lygaeoidea establish gut symbioses with environmentally acquired bacteria of the genus Burkholderia sensu lato. In the genus Burkholderia, the stink bug-associated strains form a monophyletic clade, named stink bug-associated beneficial and environmental (SBE) clade (or Caballeronia). Recently, we revealed that members of the family Largidae of the superfamily Pyrrhocoroidea are associated with Burkholderia but not specifically with the SBE Burkholderia; largid bugs harbor symbionts that belong to a clade of plant-associated group of Burkholderia, called plant-associated beneficial and environmental (PBE) clade (or Paraburkholderia). To understand the genomic features of Burkholderia symbionts of stink bugs, we isolated two symbiotic Burkholderia strains from a bordered plant bug Physopellta gutta (Pyrrhocoroidea: Largidae) and determined their complete genomes. The genome sizes of the insect-associated PBE (iPBE) are 9.5 Mb and 11.2 Mb, both of which are larger than the genomes of the SBE Burkholderia symbionts. A whole-genome comparison between two iPBE symbionts and three SBE symbionts highlighted that all previously reported symbiosis factors are shared and that 282 genes are specifically conserved in the five stink bug symbionts, over one-third of which have unknown function. Among the symbiont-specific genes, about 40 genes formed a cluster in all five symbionts; this suggests a "symbiotic island" in the genome of stink bug-associated Burkholderia.

RevDate: 2020-07-08

Popay AJ, Jensen JG, WJ Mace (2020)

Root Herbivory: Grass Species, Epichloë Endophytes and Moisture Status Make a Difference.

Microorganisms, 8(7): pii:microorganisms8070997.

The root-feeding scarab insect Costelytra giveni causes severe damage to pasture ecosystems in New Zealand. Loline alkaloids produced by some Epichloë endophytes deter this insect. In two experiments, tall fescue infected with E. coenophiala, strain AR584, and endophyte-free (Nil) controls were subjected to pulse drought stress (DS) or well-watered conditions (WW). The second experiment also included meadow fescue infected with E. uncinata. After 4-6 weeks exposure to the different conditions, roots were excised and fed to C. giveni larvae for 7 days. Relative root consumption (RC), frass production, and relative weight change (RWC) of larvae were measured and the loline content of roots determined. RC and frass output were higher for larvae feeding on Nil DS tall fescue than WW and reduced by AR584. RWC was also greater on DS than on WW Nil plants but reduced by endophyte only in DS plants. RC, frass output, and RWC of larvae were reduced by endophyte in DS and WW meadow fescue, but the effect was greater for WW plants. Loline alkaloid concentration in roots was significantly higher in DS than WW tall fescue in Experiment I but higher in WW than DS meadow fescue in Experiment II. These experiments have demonstrated that moisture status interacts with endophyte to differentially affect root herbivory in tall fescue and meadow fescue.

RevDate: 2020-07-08
CmpDate: 2020-07-08

Farinholt T, Dinh C, A Kuspa (2019)

Microbiome management in the social amoeba Dictyostelium discoideum compared to humans.

The International journal of developmental biology, 63(8-9-10):447-450.

Social amoebae and humans use common strategies to orchestrate their interactions with the bacteria in their respective environments and within their bodies. These strategies include the elimination of bacteria by phagocytosis, the establishment of mutualistic interactions, the elaboration of physical barriers, and the deployment of innate immune cells. Many of the molecular mechanisms that humans and social amoebae employ differ, but there are striking similarities that may inform studies in each organism. In this topical review we highlight the similarities and consider what we might learn by comparing these highly divergent species. We focus on recent work in Dictyostelium discoideum with hopes of stimulating work in this area and with the expectation that new mechanistic details uncovered in social amoebae-bacteria interactions will inform microbiome management in humans.

RevDate: 2020-07-07

Shi X, Gao G, Tian J, et al (2020)

Symbiosis of sulfate-reducing bacteria and methanogenic archaea in sewer systems.

Environment international, 143:105923 pii:S0160-4120(20)31878-X [Epub ahead of print].

Sulfide and methane emissions always simultaneously exist in natural environment and constitute a major topic of societal concern. However, the metabolic environments between sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) exist a great difference, which seems to be opposite to the coexisting phenomenon. To explore this issue, the comprehensive biofilm structures, substrate consuming and metabolism pathways of SRB and MA were investigated in a case study of urban sewers. The results showed that, due to the stricter environmental requirements of MA than SRB, SRB became the preponderant microorganism which promoted the rapid generation of sulfide in the initial period of biofilm formation. According to a metagenomic analysis, the SRB appeared to be more preferential than MA in sewers, and the preponderant SRB could provide a key medium (Methyl-coenzyme M) for methane metabolism. Therefore, the diversity of MA gradually increased, and the symbiosis system formed preliminarily. In addition, via L-cysteine, methane metabolism also participated in sulfide consumption which was involved in cysteine and methionine metabolism. This phenomenon of sulfide consumption led to the forward reaction of sulfide metabolism, which could promote sulfide generation while stabilizing the pH value (H+ concentration) and S2- concentrations which should have inhibited SRB and MA production. Therefore, the heavily intertwined interactions between sulfide and methane metabolism provided environmental security for SRB and MA, and completely formed the symbiosis between SRB and MA. Based on these findings, an ecological model involving synergistic mechanism between sulfide and methane generation is proposed and this model can also improve understanding on the symbiosis of SRB and MA in the natural environment.

RevDate: 2020-07-07

Meglouli H, Fontaine J, A Lounès-Hadj Sahraoui (2020)

Dioxins/furans disturb the life cycle of the arbuscular mycorrhizal fungus, Rhizophagus irregularis and chicory root elongation grown under axenic conditions.

International journal of phytoremediation [Epub ahead of print].

Arbuscular mycorrhizal fungi (AMF)-assisted phytoremediation is a promising technology for sustainable removal of hazardous pollutants like dioxins/furans (PCDD/F) from the soil. However, little is known on AMF development in the presence of the persistent organic pollutants, PCDD/F. Thus, the present work aims at investigating the impact of increasing PCDD/F concentrations on the development of both partners of the symbiosis: the AMF, Rhizophagus irregularis and the chicory roots, Cichorium intybus L. grown under axenic conditions. Our results show that even R. irregularis spore germination is not affected by PCDD/F, it occurred mainly in linear way. However, root colonization, extra-radical hyphal elongation and sporulation are reduced by 40, 30, and 75%, respectively, at the highest PCDD/F concentration. In addition, while non-mycorrhizal root growth (length and dry weight) decreased at the highest PCDD/F concentration, no negative effect was observed on the dry weight of mycorrhizal roots. In conclusion, our findings show that although high PCDD/F concentrations disturb the main stages of R. irregularis development, the AMF remains able to fulfill its life cycle in the presence of PCDD/F. Moreover, the mycorrhizal inoculation protects the host plant against PCDD/F phytotoxicity. AMF could thus represent an interesting amendment option to assist phytoremediation of PCDD/F contaminated soils.

RevDate: 2020-07-07

Tanaka A, Kamiya S, Ozaki Y, et al (2020)

A nuclear protein NsiA from Epichloë festucae interacts with a MAP kinase MpkB and regulates the expression of genes required for symbiotic infection and hyphal cell fusion.

Molecular microbiology [Epub ahead of print].

The endophytic fungus Epichloë festucae systemically colonizes the intercellular spaces of cool-season grasses to establish a mutualistic symbiosis. Hyphal growth of the endophyte within the host plant is tightly regulated and synchronized with the growth of the host plant. A genetic screen to identify symbiotic genes identified mutant FR405 that had an antagonistic interaction with the host plant. Perennial ryegrass infected with the FR405 mutant were stunted and underwent premature senescence and death. The disrupted gene in FR405 encodes a nuclear-localized protein, designated as NsiA for nuclear protein for symbiotic infection. Like previously isolated symbiotic mutants the nsiA mutant is defective in hyphal cell fusion. NsiA interacts with Ste12, a C2H2 zinc-finger transcription factor, and a MAP kinase MpkB. Both are known as essential components for cell fusion in other fungal species. In E. festucae, MpkB, but not Ste12, is essential for cell fusion. Expression of several genes required for cell fusion and symbiosis, including proA/adv-1, pro41/ham-6, ham7, ham8 and ham9 were down-regulated in the nsiA mutant. However, the NsiA orthologue in Neurospora crassa was not essential for hyphal cell fusion. These results demonstrate that the roles of NsiA and Ste12 orthologues in hyphal cell fusion are distinctive between fungal species.

RevDate: 2020-07-07

Samim SA, Singh A, P Ravi (2020)

Modified Early Warning System: Quality Improvement with the Help of Healthcare Failure Modes and Effect Analysis.

Hospital topics [Epub ahead of print].

INTRODUCTION: Hospitals struggle to implement MEWS. This study aims to improve MEWS implementation in the studied hospital.

OBJECTIVE: Improve the implementation of MEWS with the help of HFMEA. Materials: HFMEA together with training is used to improve the implementation.

RESULTS: The pre-intervention RPN got reduced from 1558 to 516 in the post-implementation phase. Application: This demonstrates improvement in the implementation of MEWS with the help of HFMEA, this study design can be widely used.

CONCLUSION: The HFMEA is an effective tool to use for the improvement of MEWS implementation by the hospital nurses.

RevDate: 2020-07-07

Carter ME, Carpenter SCD, Dubrow ZE, et al (2020)

A TAL effector-like protein of an endofungal bacterium increases the stress tolerance and alters the transcriptome of the host.

Proceedings of the National Academy of Sciences of the United States of America pii:2003857117 [Epub ahead of print].

Symbioses of bacteria with fungi have only recently been described and are poorly understood. In the symbiosis of Mycetohabitans (formerly Burkholderia) rhizoxinica with the fungus Rhizopus microsporus, bacterial type III (T3) secretion is known to be essential. Proteins resembling T3-secreted transcription activator-like (TAL) effectors of plant pathogenic bacteria are encoded in the three sequenced Mycetohabitans spp. genomes. TAL effectors nuclear-localize in plants, where they bind and activate genes important in disease. The Burkholderia TAL-like (Btl) proteins bind DNA but lack the N- and C-terminal regions, in which TAL effectors harbor their T3 and nuclear localization signals, and activation domain. We characterized a Btl protein, Btl19-13, and found that, despite the structural differences, it can be T3-secreted and can nuclear-localize. A btl19-13 gene knockout did not prevent the bacterium from infecting the fungus, but the fungus became less tolerant to cell membrane stress. Btl19-13 did not alter transcription in a plant-based reporter assay, but 15 R. microsporus genes were differentially expressed in comparisons both of the fungus infected with the wild-type bacterium vs. the mutant and with the mutant vs. a complemented strain. Southern blotting revealed btl genes in 14 diverse Mycetohabitans isolates. However, banding patterns and available sequences suggest variation, and the btl19-13 phenotype could not be rescued by a btl gene from a different strain. Our findings support the conclusion that Btl proteins are effectors that act on host DNA and play important but varied or possibly host genotype-specific roles in the M. rhizoxinica-R. microsporus symbiosis.

RevDate: 2020-07-07

Bendová B, Piálek J, Ďureje Ľ, et al (2020)

How being synanthropic affects the gut bacteriome and mycobiome: comparison of two mouse species with contrasting ecologies.

BMC microbiology, 20(1):194 pii:10.1186/s12866-020-01859-8.

BACKGROUND: The vertebrate gastrointestinal tract is colonised by microbiota that have a major effect on the host's health, physiology and phenotype. Once introduced into captivity, however, the gut microbial composition of free-living individuals can change dramatically. At present, little is known about gut microbial changes associated with adaptation to a synanthropic lifestyle in commensal species, compared with their non-commensal counterparts. Here, we compare the taxonomic composition and diversity of bacterial and fungal communities across three gut sections in synanthropic house mouse (Mus musculus) and a closely related non-synanthropic mound-building mouse (Mus spicilegus).

RESULTS: Using Illumina sequencing of bacterial 16S rRNA amplicons, we found higher bacterial diversity in M. spicilegus and detected 11 bacterial operational taxonomic units with significantly different proportions. Notably, abundance of Oscillospira, which is typically higher in lean or outdoor pasturing animals, was more abundant in non-commensal M. spicilegus. ITS2-based barcoding revealed low diversity and high uniformity of gut fungi in both species, with the genus Kazachstania clearly dominant.

CONCLUSIONS: Though differences in gut bacteria observed in the two species can be associated with their close association with humans, changes due to a move from commensalism to captivity would appear to have caused larger shifts in microbiota.

RevDate: 2020-07-07
CmpDate: 2020-07-07

Hafer-Hahmann N, C Vorburger (2020)

Parasitoids as drivers of symbiont diversity in an insect host.

Ecology letters, 23(8):1232-1241.

Immune systems have repeatedly diversified in response to parasite diversity. Many animals have outsourced part of their immune defence to defensive symbionts, which should be affected by similar evolutionary pressures as the host's own immune system. Protective symbionts provide efficient and specific protection and respond to changing selection pressure by parasites. Here we use the aphid Aphis fabae, its protective symbiont Hamiltonella defensa, and its parasitoid Lysiphlebus fabarum to test whether parasite diversity can maintain diversity in protective symbionts. We exposed aphid populations with the same initial symbiont composition to parasitoid populations that differed in their diversity. As expected, single parasitoid genotypes mostly favoured a single symbiont that was most protective against that particular parasitoid, while multiple symbionts persisted in aphids exposed to more diverse parasitoid populations, which in turn affected aphid population density and rates of parasitism. Parasite diversity may be crucial to maintaining symbiont diversity in nature.

RevDate: 2020-07-07
CmpDate: 2020-07-07

Anyasi RO, HI Atagana (2019)

Endophyte: Understanding the Microbes and its Applications.

Pakistan journal of biological sciences : PJBS, 22(4):154-167.

The ability of endophytes to colonize every plant tissue has led to the opportunity of using the microorganism in a lot of biological applications. Endophytes are beneficial to their host cells as such its application is observed in every aspects of life. This study therefore endeavored to give an analysis of endophytes, what they were and what they had been used for till the present time. Sampling of several literature studies in endophytes was done in this study to enable a complete understanding of the mechanism of application of the actions of endophytes, so as to be able to do a thorough assessment of the current state in the knowledge of the microbes. From the complete analysis of the literature on the application and use of endophytes, in nutrient asquition and increase the stress tolerance in plants. This study provided a platform for further research gaps through the presentation of what endophytes were, what they had been used for till date, the mechanism of operation of the micro-organism and the type of interaction between them and their hosts. There are still ways to improve on the methods of application of endophytes as a type of biological organism. This will be done by adjusting to the current trends in biological studies using molecular mechanization, following an intensive further study on endophyte mechanisms.

RevDate: 2020-07-07
CmpDate: 2020-07-07

Robbins SJ, Singleton CM, Chan CX, et al (2019)

A genomic view of the reef-building coral Porites lutea and its microbial symbionts.

Nature microbiology, 4(12):2090-2100.

Corals and the reef ecosystems that they support are in global decline due to increasing anthropogenic pressures such as climate change1. However, effective reef conservation strategies are hampered by a limited mechanistic understanding of coral biology and the functional roles of the diverse microbial communities that underpin coral health2,3. Here, we present an integrated genomic characterization of the coral species Porites lutea and its microbial partners. High-quality genomes were recovered from P. lutea, as well as a metagenome-assembled Cladocopium C15 (the dinoflagellate symbiont) and 52 bacterial and archaeal populations. Comparative genomic analysis revealed that many of the bacterial and archaeal genomes encode motifs that may be involved in maintaining association with the coral host and in supplying fixed carbon, B-vitamins and amino acids to their eukaryotic partners. Furthermore, mechanisms for ammonia, urea, nitrate, dimethylsulfoniopropionate and taurine transformation were identified that interlink members of the holobiont and may be important for nutrient acquisition and retention in oligotrophic waters. Our findings demonstrate the critical and diverse roles that microorganisms play within the coral holobiont and underscore the need to consider all of the components of the holobiont if we are to effectively inform reef conservation strategies.

RevDate: 2020-07-07
CmpDate: 2020-07-07

Spiga L, SE Winter (2019)

Using Enteric Pathogens to Probe the Gut Microbiota.

Trends in microbiology, 27(3):243-253.

Enteric pathogens have evolved to manipulate the interface between the host and commensal microbial communities, making these pathogenic organisms superb research tools to interrogate the function of the gut microbiota during inflammatory flares. Here, we provide an overview of conceptual insights gained from experimental infection with enteric pathogens, such as Salmonella enterica serovar Typhimurium. Metabolic pathways at the host-microbe intersection will be a particular area of focus. A better understanding of the cellular and molecular mechanisms that control host-microbe interactions during episodes of inflammation may aid in the rational design of microbiota-targeting therapies.

RevDate: 2020-07-06

Lima RM, Kylarová S, Mergaert P, et al (2020)

Unexplored Arsenals of Legume Peptides With Potential for Their Applications in Medicine and Agriculture.

Frontiers in microbiology, 11:1307.

During endosymbiosis, bacteria live intracellularly in the symbiotic organ of their host. The host controls the proliferation of endosymbionts and prevents their spread to other tissues and organs. In Rhizobium-legume symbiosis the major host effectors are secreted nodule-specific cysteine-rich (NCR) peptides, produced exclusively in the symbiotic cells. NCRs have evolved in the Inverted Repeat Lacking Clade (IRLC) of the Leguminosae family. They are secreted peptides that mediate terminal differentiation of the endosymbionts, forming polyploid, non-cultivable cells with increased membrane permeability. NCRs form an extremely large family of peptides, which have four or six conserved cysteines but otherwise highly diverse amino acid sequences, resulting in a wide variety of anionic, neutral and cationic peptides. In vitro, many synthetic NCRs have strong antimicrobial activities against both Gram-negative and Gram-positive bacteria, including the ESKAPE strains and pathogenic fungi. The spectra and minimal bactericidal and anti-fungal concentrations of NCRs differ, indicating that, in addition to their charge, the amino acid composition and sequence also play important roles in their antimicrobial activity. NCRs attack the bacteria and fungi at the cell envelope and membrane as well as intracellularly, forming interactions with multiple essential cellular machineries. NCR-like peptides with similar symbiotic functions as the NCRs also exist in other branches of the Leguminosae family. Thus, legumes provide countless and so far unexplored sources of symbiotic peptides representing an enormous resource of pharmacologically interesting molecules.

RevDate: 2020-07-06
CmpDate: 2020-07-06

Liu M, Zhao Z, Chen L, et al (2020)

Influences of arbuscular mycorrhizae, phosphorus fertiliser and biochar on alfalfa growth, nutrient status and cadmium uptake.

Ecotoxicology and environmental safety, 196:110537.

The objective of the study was to explore the influences of arbuscular mycorrhizae (AM), phosphorus (P) fertiliser, biochar application (BC) and their interactions on Medicago sativa growth, nutrient, Cd content and AM fungi-plant symbioses. Applications of both P fertiliser and BC significantly increased total biomass and P and potassium (K) uptake, regardless of AM. When no P fertiliser or BC was used, the shoot biomass and nitrogen (N), P, and K contents in the +AM treatments were 1.39, 1.54, 4.53 and 2.06 times higher than those in the -AM treatments, respectively. AM fungi only elevated the total P uptake by 44.03% when P fertiliser was applied at a rate of 30 mg P kg-1 in the absence of BC addition. With BC application or high-P fertiliser input (100 mg P kg-1), the soil available P was significantly higher than that in the other treatments, and AM fungi significantly reduced the shoot biomass. The minimum Cd concentration occurred in the shoots of alfalfas treated with BC and high-P fertiliser inputs; this concentration was lower than the maximum permitted concentration in China. Although the BC and high-P inputs could eliminate the positive mycorrhizal response, the results suggested that BC application in combination with high-P fertiliser input could not only increase forage yields but also lower Cd concentrations to meet the forage safety standards by the dilution effect.

RevDate: 2020-07-06
CmpDate: 2020-07-06

Pearson T, Sahl JW, Hepp CM, et al (2020)

Pathogen to commensal? Longitudinal within-host population dynamics, evolution, and adaptation during a chronic >16-year Burkholderia pseudomallei infection.

PLoS pathogens, 16(3):e1008298.

Although acute melioidosis is the most common outcome of Burkholderia pseudomallei infection, we have documented a case, P314, where disease severity lessened with time, and the pathogen evolved towards a commensal relationship with the host. In the current study, we used whole-genome sequencing to monitor this long-term symbiotic relationship to better understand B. pseudomallei persistence in P314's sputum despite intensive initial therapeutic regimens. We collected and sequenced 118 B. pseudomallei isolates from P314's airways over a >16-year period, and also sampled the patient's home environment, recovering six closely related B. pseudomallei isolates from the household water system. Using comparative genomics, we identified 126 SNPs in the core genome of the 124 isolates or 162 SNPs/indels when the accessory genome was included. The core SNPs were used to construct a phylogenetic tree, which demonstrated a close relationship between environmental and clinical isolates and detailed within-host evolutionary patterns. The phylogeny had little homoplasy, consistent with a strictly clonal mode of genetic inheritance. Repeated sampling revealed evidence of genetic diversification, but frequent extinctions left only one successful lineage through the first four years and two lineages after that. Overall, the evolution of this population is nonadaptive and best explained by genetic drift. However, some genetic and phenotypic changes are consistent with in situ adaptation. Using a mouse model, P314 isolates caused greatly reduced morbidity and mortality compared to the environmental isolates. Additionally, potentially adaptive phenotypes emerged and included differences in the O-antigen, capsular polysaccharide, motility, and colony morphology. The >13-year co-existence of two long-lived lineages presents interesting hypotheses that can be tested in future studies to provide additional insights into selective pressures, niche differentiation, and microbial adaptation. This unusual melioidosis case presents a rare example of the evolutionary progression towards commensalism by a highly virulent pathogen within a single human host.

RevDate: 2020-07-06
CmpDate: 2020-07-06

Montesinos-Navarro A, Díaz G, Torres P, et al (2019)

Phylogenetic rewiring in mycorrhizal-plant interaction networks increases community stability in naturally fragmented landscapes.

Communications biology, 2:452.

Although ecological networks are usually considered a static representation of species' interactions, the interactions can change when the preferred partners are absent (rewiring). In mutualistic networks, rewiring with non-preferred partners can palliate extinction cascades, contributing to communities' stability. In spite of its significance, whether general patterns can shape the rewiring of ecological interactions remains poorly understood. Here, we show a phylogenetic constraint in the rewiring of mycorrhizal networks, so that rewired interactions (i.e., with non-preferred hosts) tend to involve close relatives of preferred hosts. Despite this constraint, rewiring increases the robustness of the fungal community to the simulated loss of their host species. We identify preferred and non-preferred hosts based on the probability that, when the two partners co-occur, they actually interact. Understanding general patterns in the rewiring of interactions can improve our predictions of community responses to interactions' loss, which influences how global changes will affect ecosystem stability.

RevDate: 2020-07-06
CmpDate: 2020-07-06

Witchley JN, Penumetcha PM, SM Noble (2019)

Visualization of Candida albicans in the Murine Gastrointestinal Tract Using Fluorescent In Situ Hybridization.

Journal of visualized experiments : JoVE.

Candida albicans is a fungal component of the gut microbiota in humans and many other mammals. Although C. albicans does not cause symptoms in most colonized hosts, the commensal reservoir does serve as a repository for infectious disease, and the presence of high fungal titers in the gut is associated with inflammatory bowel disease. Here, we describe a method to visualize C. albicans cell morphology and localization in a mouse model of stable gastrointestinal colonization. Colonization is established using a single dose of C. albicans in animals that have been treated with oral antibiotics. Segments of gut tissue are fixed in a manner that preserves the architecture of luminal contents (microorganisms and mucus) as well as the host mucosa. Finally, fluorescent in situ hybridization is performed using probes against fungal rRNA to stain for C. albicans and hyphae. A key advantage of this protocol is that it allows for simultaneous observation of C. albicans cell morphology and its spatial association with host structures during gastrointestinal colonization.

RevDate: 2020-07-06
CmpDate: 2020-07-06

Ulrich DEM, Sevanto S, Ryan M, et al (2019)

Plant-microbe interactions before drought influence plant physiological responses to subsequent severe drought.

Scientific reports, 9(1):249.

We examined the effect of soil microbial communities on plant physiological responses to drought. Bouteloua gracilis seeds were planted in sterilized sand with (inoculated) and without (controls) soil microbial communities. After substantial growth, drought was imposed by completely withholding water. Before soil moisture declined to zero, inoculated plants germinated faster, were significantly taller, and maintained greater soil moisture than controls. The greater soil moisture of the inoculated plants allowed greater photosynthesis but also induced lower tissue drought tolerance (as indicated by turgor loss point) compared to controls. The inoculated plants were more susceptible to severe drought compared to control plants as indicated by significantly lower mean stomatal conductance, as well as marginally significantly greater mean wilting score, for the entire severe drought period after soil moisture declined to zero. Inoculated plants exhibited enhanced growth and photosynthesis and dampened drought stress over short timescales, but also increased susceptibility to drought over long timescales. This work demonstrates (1) an unexpected insight that microbes can have positive initial effects on plant performance, but negative impacts on plant performance during severe drought, and (2) that microbially altered effects on plant function during well-watered and moderate drought conditions can influence plant function under subsequent severe drought.

RevDate: 2020-07-05

Morvan S, Meglouli H, Lounès-Hadj Sahraoui A, et al (2020)

Into the wild blueberry (Vaccinium angustifolium) rhizosphere microbiota.

Environmental microbiology [Epub ahead of print].

The ability of wild blueberries to adapt to their harsh environment is believed to be closely related to their symbiosis with ericoid mycorrhizal fungi which produce enzymes capable of organic matter mineralization. Although some of these fungi have been identified and characterized, we still know little about the microbial ecology of wild blueberry. Our study aims to characterize the fungal and bacterial rhizosphere communities of Vaccinium angustifolium (the main species encountered in wild blueberry fields). Our results clearly show that the fungal order Helotiales was the most abundant taxon associated with V. angustifolium. Helotiales contains most of the known ericoid mycorrhizal fungi which are expected to dominate in such a biotope. Furthermore, we found the dominant bacterial order was the nitrogen-fixing Rhizobiales. The Bradyrhizobium genus whose members are known to form nodules with legumes, was among the ten most abundant genera in the bacterial communities. In addition, Bradyrhizobium and Roseiarcus sequences significantly correlated with higher leaf-nitrogen content. Overall our data documented fungal and bacterial community structure differences in three wild blueberry production fields. This article is protected by copyright. All rights reserved.

RevDate: 2020-07-04

Heryanto C, I Eleftherianos (2020)

Nematode endosymbiont competition: Fortune favors the fittest.

Molecular and biochemical parasitology pii:S0166-6851(20)30062-1 [Epub ahead of print].

Endosymbiotic bacteria that obligately associate with entomopathogenic nematodes as a complex are a unique model system to study competition. These nematodes seek an insect host and provide entry for their endosymbionts. Through their natural products, the endosymbionts nurture their nematodes by eliminating secondary infection, providing nutrients through bioconversion of the insect cadaver, and facilitating reproduction. On one hand, they cooperatively colonize the insect host and neutralize other opportunistic biotic threats. On the other hand, inside the insect cadaver as a fighting pit, they fiercely compete for the fittest partnership that will grant them the reproductive dominance. Here, we review the protective and nurturing nature of endosymbiotic bacteria for their nematodes and how their selective preference shapes the superior nematode-endosymbiont pairs as we know today.

RevDate: 2020-07-04

Yu L, Li T, Li L, et al (2020)

SAGER: a database of Symbiodiniaceae and Algal Genomic Resource.

Database : the journal of biological databases and curation, 2020:.

Symbiodiniaceae dinoflagellates are essential endosymbionts of reef building corals and some other invertebrates. Information of their genome structure and function is critical for understanding coral symbiosis and bleaching. With the rapid development of sequencing technology, genome draft assemblies of several Symbiodiniaceae species and diverse marine algal genomes have become publicly available but spread in multiple separate locations. Here, we present a Symbiodiniaceae and Algal Genomic Resource Database (SAGER), a user-friendly online repository for integrating existing genomic data of Symbiodiniaceae species and diverse marine algal gene sets from MMETSP and PhyloDB databases. Relevant algal data are included to facilitate comparative analyses. The database is freely accessible at http://sampgr.org.cn. It provides comprehensive tools for studying gene function, expression and comparative genomics, including search tools to identify gene information from Symbiodiniaceae species, and BLAST tool to find orthologs from marine algae and protists. Moreover, SAGER integrates transcriptome datasets derived from diverse culture conditions of corresponding Symbiodiniaceae species. SAGER was developed with the capacity to incorporate future Symbiodiniaceae and algal genome and transcriptome data, and will serve as an open-access and sustained platform providing genomic and molecular tools that can be conveniently used to study Symbiodiniaceae and other marine algae. Database URL: http://sampgr.org.cn.

RevDate: 2020-07-04

Cesaro P, Massa N, Cantamessa S, et al (2020)

Tomato responses to Funneliformis mosseae during the early stages of arbuscular mycorrhizal symbiosis.

Mycorrhiza pii:10.1007/s00572-020-00973-9 [Epub ahead of print].

The concept of symbiosis can be described as a continuum of interactions between organisms ranging from mutualism to parasitism that can also change over time. Arbuscular mycorrhizal fungi (AMF) are among the most important obligate plant symbionts. Once the symbiosis is well established, mycorrhizal plants are more tolerant to biotic or abiotic stresses, so the AMF relationship with the host plant is generally described as mutualistic. However, little is known about AMF effects on the plant during the early stages of root colonization. The aim of this work was to assess the type of interaction (mutualistic or parasitic) between the arbuscular mycorrhizal (AM) fungus Funelliformis mosseae and Solanum lycopersicum cv. Rio Grande plants, at 7, 14, 21, and 28 days after inoculation (DAI), considering that in the adopted experimental design (one plant per pot), the seedling was the only carbon source for fungus development in the absence of common mycorrhizal networks with other plants. At each harvest, mycorrhizal colonization, shoot and root weights, morphometric parameters, and photosynthetic efficiency were evaluated. The presence of the AM fungus in the tomato root system was observed starting from the 14th DAI, and its level increased over time. Few effects of the fungus presence on the considered parameters were observed, and no stress symptoms ever appeared; so, we can state that the fungus behaved as a mutualistic symbiont during the early stages of plant growth. Moreover, a trend towards a positive effect on plant growth was observed at 28 DAI in mycorrhizal plants.

RevDate: 2020-07-04

Nimkar S, Joshi S, Kinikar A, et al (2020)

Mullen Scales of Early Learning Adaptation for Assessment of Indian Children and Application to Tuberculous Meningitis.

Journal of tropical pediatrics pii:5867268 [Epub ahead of print].

INTRODUCTION: Tuberculous meningitis (TBM) results in significant morbidity and mortality among children worldwide. Associated neurocognitive complications are common but not well characterized. The Mullen Scales of Early Learning (MSEL), a well-established measure for assessment of neurodevelopment, has not yet been adapted for use in India. This study's goal was to adapt the MSEL for local language and culture to assess neurocognition among children in India, and apply the adapted measure for assessment of children with TBM.

METHODS: Administration of MSEL domains was culturally adapted. Robust translation procedures for instructions took place for three local languages: Marathi, Hindi and Tamil. Multilingual staff compared instructions against the original version for accuracy. The MSEL stimuli and instructions were reviewed by psychologists and pediatricians in India to identify items concerning for cultural bias.

RESULTS: MSEL stimuli unfamiliar to children in this setting were identified and modified within Visual Reception, Fine-Motor, Receptive Language and Expressive Language Scales. Item category was maintained for adaptations of items visually or linguistically different from those observed in daily life. Adjusted items were administered to six typically developing children to determine modification utility. Two children diagnosed with confirmed TBM (ages 11 and 29 months) were evaluated with the adapted MSEL before receiving study medications. Skills were below age-expectation across visual reception, fine motor and expressive language domains.

CONCLUSIONS: This is the first study to assess children with TBM using the MSEL adapted for use in India. Future studies in larger groups of Indian children are warranted to validate the adapted measure.

RevDate: 2020-07-03

Si Z, Guan N, Zhou Y, et al (2020)

A Methionine Sulfoxide Reductase B is Required for the Etablishment of Astragalus sinicus-Mesorhizobium Symbiosis.

Plant & cell physiology pii:5866985 [Epub ahead of print].

Methionine sulfoxide reductase B (MsrB) is involved in oxidative stress or defense responses in plants. However, little is known about its role in legume-rhizobium symbiosis. In this work, an MsrB gene was identified from Astragalus sinicus and its function in symbiosis was characterized. AsMsrB was induced under phosphorus starvation and displayed different expression patterns under symbiotic and non-symbiotic conditions. Hydrogen peroxide or methyl viologen treatment enhanced the transcript level of AsMsrB in roots and nodules. Subcellular localization showed that AsMsrB was localized in the cytoplasm of onion epidermal cells and co-localized with rhizobia in nodules. Plants with AsMsrB-RNAi hairy roots exhibited significant decreases in nodule number, nodule nitrogenase activity and fresh weight of aerial part, as well as abnormal nodule and symbiosome development. Statistics of infection events showed that plants with AsMsrB-RNAi hairy roots had significant decreases in the number of root hair curling events, infection threads and nodule primordia compared with the control. The content of hydrogen peroxide increased in AsMsrB-RNAi roots while decreased in AsMsrB over-expression roots at the early stage of infection. The transcriptome analysis showed synergistic modulations of the expression of genes involved in ROS generation and scavenging, defense and pathogenesis, and early nodulation. In addition, a candidate protein interacting with AsMsrB was identified and confirmed by bimolecular fluorescence complementation. Taken together, our results indicate that AsMsrB plays an essential role in nodule development and symbiotic nitrogen fixation by affecting the redox homeostasis in roots and nodules.

RevDate: 2020-07-03

Jang SW, Yoou MH, Hong WJ, et al (2020)

Re-Analysis of 16S Amplicon Sequencing Data Reveals Soil Microbial Population Shifts in Rice Fields under Drought Condition.

Rice (New York, N.Y.), 13(1):44 pii:10.1186/s12284-020-00403-6.

Rice (Oryza sativa. L) has been intensively studied to ensure a stable global supply of this commodity in the face of rapid global climate change. A critical factor that decreases crop yield is drought, which has been analyzed in various ways through many researches. Microbiome-based studies of rice investigate the symbiosis between rice and bacteria, which has been proposed as a way to overcome problems caused by drought. Several rice-associated metagenomic profiles obtained under drought conditions have been reported since the advent of next generation sequencing (NGS) technology. To elucidate the future diversity of plants and microorganisms and to promote sustainable agriculture, we reanalyzed 64 of the publicly available 16S amplicon sequencing data produced under drought condition. In the process of integrating data sets, however, we found an inconsistency that serves as a bottleneck for microbiome-based sustainability research. While this report provides clues about the composition of the microbiome under the drought conditions, the results are affected by differences in the location of the experiments, sampling conditions, and analysis protocols. Re-analysis of amplicon sequencing data of the soil microbiome in rice fields suggests that microbial composition shifts in response to drought condition and the presence of plants. Among the bacteria involved, the phylum Proteobacteria appears to play the most important role in the survival of rice under drought condition.

RevDate: 2020-07-03

Preethish-Kumar V, Shah A, Kumar M, et al (2020)

In Vivo Evaluation of White Matter Abnormalities in Children with Duchenne Muscular Dystrophy Using DTI.

AJNR. American journal of neuroradiology pii:ajnr.A6604 [Epub ahead of print].

BACKGROUND AND PURPOSE: Duchenne muscular dystrophy is an X-linked disorder characterized by progressive muscle weakness and prominent nonmotor manifestations, such as a low intelligence quotient and neuropsychiatric disturbance. We investigated WM integrity in patients with Duchenne muscular dystrophy using DTI.

MATERIALS AND METHODS: Fractional anisotropy and mean, axial, and radial diffusivity (DTI measures) were used to assess WM microstructural integrity along with neuropsychological evaluation in patients with Duchenne muscular dystrophy (n = 60) and controls (n = 40). Exon deletions in the DMD gene were confirmed using multiplex ligation-dependent probe amplification. Patients were classified into proximal (DMD Dp140+) and distal (DMD Dp140-) subgroups based on the location of the exon deletion and expression of short dystrophin Dp140 isoform. WM integrity was examined using whole-brain Tract-Based Spatial Statistics and atlas-based analysis of DTI data. The Pearson correlation was performed to investigate the possible relationship between neuropsychological scores and DTI metrics.

RESULTS: The mean ages of Duchenne muscular dystrophy and control participants were 8.0 ± 1.2 years and 8.2 ± 1.4 years, respectively. The mean age at disease onset was 4.1 ± 1.8 years, and mean illness duration was 40.8 ± 25.2 months. Significant differences in neuropsychological scores were observed between the proximal and distal gene-deletion subgroups, with more severe impairment in the distal-deletion subgroup (P < .05). Localized fractional anisotropy changes were seen in the corpus callosum, parietal WM, and fornices in the patient subgroup with Dp140+, while widespread changes were noted in the Dp140- subgroup. The Dp140+ subgroup showed increased axial diffusivity in multiple WM regions relative to the Dp140- subgroup. No significant correlation was observed between clinical and neuropsychological scores and diffusion metrics.

CONCLUSIONS: Widespread WM differences are evident in patients with Duchenne muscular dystrophy relative to healthy controls. Distal mutations in particular are associated with extensive WM abnormalities and poor neuropsychological profiles.

RevDate: 2020-07-03

Koch EJ, Moriano-Gutierrez S, Ruby EG, et al (2020)

The impact of persistent colonization by Vibrio fischeri on the metabolome of the host squid Euprymna scolopes.

The Journal of experimental biology pii:jeb.212860 [Epub ahead of print].

Associations between animals and microbes affect not only the immediate tissues where they occur, but also the entire host. Metabolomics, the study of small biomolecules generated during metabolic processes, provides a window into how mutualistic interactions shape host biochemistry. The Hawaiian bobtail squid, Euprymna scolopes, is amenable to metabolomic studies of symbiosis because the host can be reared with or without its species-specific symbiont, Vibrio fischeri In addition, unlike many invertebrates, the host squid has a closed circulatory system. This feature allows a direct sampling of the refined collection of metabolites circulating through the body, a focused approach that has been highly successful with mammals. Here, we show that rearing E. scolopes without its natural symbiont significantly affected one quarter of the more than 100 hemolymph metabolites defined by gas chromatography mass-spectrometry analysis. Further, as in mammals, which harbor complex consortia of bacterial symbionts, the metabolite signature oscillated on symbiont-driven daily rhythms and was dependent on the sex of the host. Thus, our results provide evidence that the population of even a single symbiont species can influence host hemolymph biochemistry as a function of symbiotic state, host sex, and circadian rhythm.

RevDate: 2020-07-03

Bréchignac F (2020)

Neglecting the ecosystemic dimension of life hinders efficient environmental protection from radiation and other hazards.

International journal of radiation biology [Epub ahead of print].

Purpose Recent efforts undertaken by the radioecology community to protect the environment against radiation have largely ignored the ecosystem concept. Instead, it has simply transferred to non human biota the concepts and methods developped for human radioprotection. This oversimplification, rooted within a narrow anthropocentric view dominating radiation protection, is prone to lead ecological risk assessment to miss its objectives.Conclusions One key challenge for radiation research when facing this general context is to widen traditional radiation biology, focused on DNA and cells of individual organisms, towards radiation ecology featuring an ecosystem-centered conceptualization. If life is driven by processes that act at subsystem level, i.e. the molecular engineering that founds the organisms' physiology, it depends as well on processes that act at system level, i.e. emergent properties of the ecosystem dimension (life support, symbiosis, resilience, biodiversity,…) since both types of processes have jointly emerged through evolution. It is worthwhile strengthening that this problem is not specific to radiation protection only. Organisms and populations of species only exist as embedded within an ecosystem featuring multispecies interactions. Ecosystems exhibit specific behaviors that find pertinent explanation through the complex systems theory, and this leads to several implications for ecological risk assessment in general. Environment protection measures that are developed exclusively from subsystem understanding (dose-response curves established for individual organisms) for practical reasons, as in current protection guidance, may actually miss their protection objective and explain some recently reported discrepancies in assessing ecological impact. Indeed, one observes that none of the methodologies in use today for environmental risk assessment has allowed to predict the ongoing dramatic biodiversity decline. It is strengthened finally that most current critical environmental issues such as global change, biodiversity decline, pollutions impact, etc…, are ecosystem-centered, and as such, they cannot be correctly understood without adopting more ecocentric approaches.

RevDate: 2020-07-03
CmpDate: 2020-07-03

Russell SL, Chappell L, W Sullivan (2019)

A symbiont's guide to the germline.

Current topics in developmental biology, 135:315-351.

Microbial symbioses exhibit astounding adaptations, yet all symbionts face the problem of how to reliably associate with host offspring every generation. A common strategy is vertical transmission, in which symbionts are directly transmitted from the female to her offspring. The diversity of symbionts and vertical transmission mechanisms is as expansive as the diversity of eukaryotic host taxa that house them. However, there are several common themes among these mechanisms based on the degree to which symbionts associate with the host germline during transmission. In this review, we detail three distinct vertical transmission strategies, starting with associations that are transmitted from host somatic cells to offspring somatic cells, either due to lacking a germline or avoiding it. A second strategy involves somatically-localized symbionts that migrate into the germline during host development. The third strategy we discuss is one in which the symbiont maintains continuous association with the germline throughout development. Unexpectedly, the vast majority of documented vertically inherited symbionts rely on the second strategy: soma-to-germline migration. Given that not all eukaryotes contain a sequestered germline and instead produce offspring from somatic stem cell lineages, this soma-to-germline migration is discussed in the context of multicellular evolution. Lastly, as recent genomics data have revealed an abundance of horizontal gene transfer events from symbiotic and non-symbiotic bacteria to host genomes, we discuss their impact on eukaryotic host evolution.

RevDate: 2020-07-02

Rizzo AE, Almeida Dos Santos S, E da Conceição Guerreiro Couto (2020)

First report of Labrorostratus caribensis (Annelida, Oenonidae) as endoparasite of Haplosyllis rosenalessoae (Annelida, Syllidae) from Brazil.

International journal for parasitology. Parasites and wildlife, 12:64-66 pii:S2213-2244(20)30038-9.

In this study, we report the second endoparasitic relationship for the oenonid Labrorostratus caribensis, previously described parasitizing a nereid polychaete. The new host is the syllid Haplosyllis rosenalessoae, in which it occupies 2/3 of its body cavity host. This is the second endoparasitic relationship between polychaetes and the first between both partners in known for Brazil, as well as the first record of the parasite outside the type locality (Caribbean) and of the host in the State of Bahia. We discuss on the interest of the finding of these king of parasitic relationships and provide an identification key to all knwon species of Labrorostratus.

RevDate: 2020-07-02

Ranjbar Sistani N, Desalegn G, Kaul HP, et al (2020)

Seed Metabolism and Pathogen Resistance Enhancement in Pisum sativum During Colonization of Arbuscular Mycorrhizal Fungi: An Integrative Metabolomics-Proteomics Approach.

Frontiers in plant science, 11:872.

Pulses are one of the most important categories of food plants, and Pea (Pisum sativum L.) as a member of pulses is considered a key crop for food and feed and sustainable agriculture. Integrative multi-omics and microsymbiont impact studies on the plant's immune system are important steps toward more productive and tolerant food plants and thus will help to find solutions against food poverty. Didymella pinodes is a main fungal pathogen of pea plants. Arbuscular mycorrhizal fungi (AMF) promote plant growth and alleviate various stresses. However, it remained unclear as to how the AMF effect on seed metabolism and how this influences resistance against the pathogen. This study assesses the AMF impacts on yield components and seed quality upon D. pinodes infection on two different P. sativum cultivars, susceptible versus tolerant, grown in pots through phenotypic and seed molecular analyses. We found that AMF symbiosis affects the majority of all tested yield components as well as a reduction of disease severity in both cultivars. Seeds of mycorrhizal pea plants showed strong responses of secondary metabolites with nutritional, medicinal, and pharmaceutical attributes, also involved in pathogen response. This is further supported by proteomic data, functionally determining those primary and secondary metabolic pathways, involved in pathogen response and induced upon AMF-colonization. The data also revealed cultivar specific effects of AMF symbiosis that increase understanding of genotype related differences. Additionally, a suite of proteins and secondary metabolites are presented, induced in seeds of P. sativum upon AMF-colonization and pathogen attack, and possibly involved in induced systemic resistance against D. pinodes, useful for modern breeding strategies implementing microsymbionts toward increased pathogen resistance.

RevDate: 2020-07-02

Egan S, Fukatsu T, MP Francino (2020)

Opportunities and Challenges to Microbial Symbiosis Research in the Microbiome Era.

Frontiers in microbiology, 11:1150.

RevDate: 2020-07-02

Hashimoto S, Goto K, Pyromyou P, et al (2020)

Type III Secretion System of Bradyrhizobium sp. SUTN9-2 Obstructs Symbiosis with Lotus spp.

Microbes and environments, 35(3):.

The rhizobial type III secretion system secretes effector proteins into host plant cells, which may either promote or inhibit symbiosis with legumes. We herein demonstrated that the type III secretion system of Bradyrhizobium sp. SUTN9-2 obstructed symbiosis with Lotus japonicus Miyakojima, L. japonicus Gifu, and Lotus burttii. A mutant of SUTN9-2 that is unable to secrete effector proteins showed better nodulation and plant growth promotion than wild-type SUTN9-2 when paired with these Lotus spp. We propose that SUTN9-2 is a useful strain for understanding the mechanisms by which effector proteins obstruct symbiosis between Bradyrhizobium and Lotus spp.

RevDate: 2020-07-02
CmpDate: 2020-07-02

Roossinck MJ (2019)

Viruses in the phytobiome.

Current opinion in virology, 37:72-76.

The phytobiome, defined as plants and all the entities that interact with them, is rich in viruses, but with the exception of plant viruses of crop plants, most of the phytobiome viruses remain very understudied. This review focuses on the neglected portions of the phytobiome, including viruses of other microbes interacting with plants, viruses in the soil, viruses of wild plants, and relationships between viruses and the vectors of plant viruses.

RevDate: 2020-07-02
CmpDate: 2020-07-02

Seo SU, MN Kweon (2019)

Virome-host interactions in intestinal health and disease.

Current opinion in virology, 37:63-71.

The enteric virome consists largely of bacteriophages and prophages related to commensal bacteria. Bacteriophages indirectly affect the host immune system by targeting their associated bacteria; however, studies suggest that bacteriophages also have distinct pathways that enable them to interact directly with the host. Eukaryotic viruses are less abundant than bacteriophages but are more efficient in the stimulation of host immune responses. Acute, permanent, and latent viral infections are detected by different types of pattern recognition receptors and induce host immune responses, including the antiviral type I interferon response. Understanding the complex interplay between commensal microorganisms and the host immune system is a prerequisite to elucidating their role in intestinal diseases.

RevDate: 2020-07-02
CmpDate: 2020-07-02

Beller L, J Matthijnssens (2019)

What is (not) known about the dynamics of the human gut virome in health and disease.

Current opinion in virology, 37:52-57.

The human gut virome has an important role in human health but its dynamics remain poorly understood. Few longitudinal studies in healthy adults showed a stable temporal gut virome, with high inter-individual diversity. In contrast, the infant virome shows a high temporal intra-individual diversity. Unfortunately, these virome studies ignore an enormous amount of unknown 'dark matter' sequences, leading to incomplete analyses and possibly incorrect conclusions. Also, the interactions between prokaryotes and bacteriophages in the gut seem to be too complex for currently available models. Therefore, there is a huge need of larger longitudinal cohort studies focusing on both the bacterial and viral component of the microbiome to be able to describe and understand this complex ecosystem.

RevDate: 2020-07-02
CmpDate: 2020-07-02

Winkler ES, LB Thackray (2019)

A long-distance relationship: the commensal gut microbiota and systemic viruses.

Current opinion in virology, 37:44-51.

Recent advances defining the role of the commensal gut microbiota in the development, education, induction, function, and maintenance of the mammalian immune system inform our understanding of how immune responses govern the outcome of systemic virus infection. While characterization of the impact of the local oral, respiratory, dermal and genitourinary microbiota on host immune responses and systemic virus infection is in its infancy, the gut microbiota interacts with host immunity systemically and at distal non-gastrointestinal tract sites to modulate the pathogenesis of systemic viruses. Gut microbes, microbe-associated molecular patterns, and microbe-derived metabolites engage receptors expressed on the cell surface, in the endosome, or in the cytoplasm to orchestrate optimal innate and adaptive immune responses important for controlling systemic virus infection.

RevDate: 2020-07-02
CmpDate: 2020-07-02

Thu MJ, Qiu Y, Kataoka-Nakamura C, et al (2019)

Isolation of Rickettsia, Rickettsiella, and Spiroplasma from Questing Ticks in Japan Using Arthropod Cells.

Vector borne and zoonotic diseases (Larchmont, N.Y.), 19(7):474-485.

Ticks are blood-sucking ectoparasites that transmit zoonotic pathogens to humans and animals. Ticks harbor not only pathogenic microorganisms but also endosymbionts. Although some tick endosymbionts are known to be essential for the survival of ticks, their roles in ticks remain poorly understood. The main aim of this study was to isolate and characterize tick-borne microorganisms from field-collected ticks using two arthropod cell lines derived from Ixodes scapularis embryos (ISE6) and Aedes albopictus larvae (C6/36). A total of 170 tick homogenates originating from 15 different tick species collected in Japan were inoculated into each cell line. Bacterial growth was confirmed by PCR amplification of 16S ribosomal DNA (rDNA) of eubacteria. During the 8-week observation period, bacterial isolation was confirmed in 14 and 4 samples using ISE6 and C6/36 cells, respectively. The sequencing analysis of the 16S rDNA PCR products indicated that they were previously known tick-borne pathogens/endosymbionts in three different genera: Rickettsia, Rickettsiella, and Spiroplasma. These included four previously validated rickettsial species namely Rickettsia asiatica (n = 2), Rickettsia helvetica (n = 3), Rickettsia monacensis (n = 2), and Rickettsia tamurae (n = 3) and one uncharacterized genotype Rickettsia sp. LON (n = 2). Four isolates of Spiroplasma had the highest similarity with previously reported Spiroplasma isolates: Spiroplasma ixodetis obtained from ticks in North America and Spiroplasma sp. Bratislava 1 obtained from Ixodes ricinus in Europe, while two isolates of Rickettsiella showed 100% identity with Rickettsiella sp. detected from Ixodes uriae at Grimsey Island in Iceland. To the best of our knowledge, this is the first report on successful isolation of Rickettsiella from ticks. The isolates obtained in this study can be further analyzed to evaluate their pathogenic potential in animals and their roles as symbionts in ticks.

RevDate: 2020-07-01

Attané C, C Muller (2020)

Drilling for Oil: Tumor-Surrounding Adipocytes Fueling Cancer.

Trends in cancer, 6(7):593-604.

Over the past decade, it has become apparent that metabolic reprogramming is a key event in tumor progression. The tumor microenvironment (TME) is a source of metabolites for tumor cells. Lipid-filled mature adipocytes are frequently found in proximity to invasive human tumors and release free fatty acids (FFAs) through lipolysis. These FFAs are taken up by tumor cells and used to promote tumor progression by mechanisms that include mitochondrial fatty acid oxidation (FAO). This review discusses recent advances in our understanding of this metabolic symbiosis between adipocytes and cancer cells and underlines the differences in this metabolic crosstalk between the various types of cancer and their localization.

RevDate: 2020-07-01

Cabello AM, Turk-Kubo KA, Hayashi K, et al (2020)

Unexpected presence of the nitrogen-fixing symbiotic cyanobacterium UCYN-A in Monterey Bay, California.

Journal of phycology [Epub ahead of print].

In the last decade, the known biogeography of nitrogen fixation in the ocean has been expanded to colder and nitrogen-rich coastal environments. The symbiotic nitrogen-fixing cyanobacteria group A (UCYN-A) has been revealed as one of the most abundant and widespread nitrogen-fixers, and includes several sublineages that live associated with genetically distinct but closely related prymnesiophyte hosts. The UCYN-A1 sublineage is associated with an open ocean picoplanktonic prymnesiophyte, whereas UCYN-A2 is associated with the coastal nanoplanktonic coccolithophore Braarudosphaera bigelowii, suggesting that different sublineages may be adapted to different environments. Here, we study the diversity of nifH genes present at the Santa Cruz Municipal Wharf in the Monterey Bay (MB), California, and report for the first time the presence of multiple UCYN-A sublineages, unexpectedly dominated by the UCYN-A2 sublineage. Sequence and quantitative PCR data over an 8-year time-series (2011-2018) show a shift towards increasing UCYN-A2 abundances after 2013, and a marked seasonality for this sublineage which was present during summer-fall months, coinciding with the upwelling-relaxation period in the MB. Increased abundances corresponded to positive temperature anomalies in MB, and we discuss the possibility of a benthic life stage of the associated coccolithophore host to explain the seasonal pattern. The dominance of UCYN-A2 in coastal waters of the MB underscores the need to further explore the habitat preference of the different sublineages in order to provide additional support for the hypothesis that UCYN-A1 and UCYN-A2 sublineages are different ecotypes.

RevDate: 2020-07-01

Altamia MA, Lin Z, Trindade-Silva AE, et al (2020)

Secondary Metabolism in the Gill Microbiota of Shipworms (Teredinidae) as Revealed by Comparison of Metagenomes and Nearly Complete Symbiont Genomes.

mSystems, 5(3): pii:5/3/e00261-20.

Shipworms play critical roles in recycling wood in the sea. Symbiotic bacteria supply enzymes that the organisms need for nutrition and wood degradation. Some of these bacteria have been grown in pure culture and have the capacity to make many secondary metabolites. However, little is known about whether such secondary metabolite pathways are represented in the symbiont communities within their hosts. In addition, little has been reported about the patterns of host-symbiont co-occurrence. Here, we collected shipworms from the United States, the Philippines, and Brazil and cultivated symbiotic bacteria from their gills. We analyzed sequences from 22 shipworm gill metagenomes from seven shipworm species and from 23 cultivated symbiont isolates. Using (meta)genome sequencing, we demonstrate that the cultivated isolates represent all the major bacterial symbiont species and strains in shipworm gills. We show that the bacterial symbionts are distributed among shipworm hosts in consistent, predictable patterns. The symbiotic bacteria harbor many gene cluster families (GCFs) for biosynthesis of bioactive secondary metabolites, only <5% of which match previously described biosynthetic pathways. Because we were able to cultivate the symbionts and to sequence their genomes, we can definitively enumerate the biosynthetic pathways in these symbiont communities, showing that ∼150 of ∼200 total biosynthetic gene clusters (BGCs) present in the animal gill metagenomes are represented in our culture collection. Shipworm symbionts occur in suites that differ predictably across a wide taxonomic and geographic range of host species and collectively constitute an immense resource for the discovery of new biosynthetic pathways corresponding to bioactive secondary metabolites.IMPORTANCE We define a system in which the major symbionts that are important to host biology and to the production of secondary metabolites can be cultivated. We show that symbiotic bacteria that are critical to host nutrition and lifestyle also have an immense capacity to produce a multitude of diverse and likely novel bioactive secondary metabolites that could lead to the discovery of drugs and that these pathways are found within shipworm gills. We propose that, by shaping associated microbial communities within the host, the compounds support the ability of shipworms to degrade wood in marine environments. Because these symbionts can be cultivated and genetically manipulated, they provide a powerful model for understanding how secondary metabolism impacts microbial symbiosis.

RevDate: 2020-07-01

Lefoulon E, Clark T, Borveto F, et al (2020)

Pseudoscorpion Wolbachia symbionts: diversity and evidence for a new supergroup S.

BMC microbiology, 20(1):188 pii:10.1186/s12866-020-01863-y.

BACKGROUND: Wolbachia are the most widely spread endosymbiotic bacteria, present in a wide variety of insects and two families of nematodes. As of now, however, relatively little genomic data has been available. The Wolbachia symbiont can be parasitic, as described for many arthropod systems, an obligate mutualist, as in filarial nematodes or a combination of both in some organisms. They are currently classified into 16 monophyletic lineage groups ("supergroups"). Although the nature of these symbioses remains largely unknown, expanded Wolbachia genomic data will contribute to understanding their diverse symbiotic mechanisms and evolution.

RESULTS: This report focuses on Wolbachia infections in three pseudoscorpion species infected by two distinct groups of Wolbachia strains, based upon multi-locus phylogenies. Geogarypus minor harbours wGmin and Chthonius ischnocheles harbours wCisc, both closely related to supergroup H, while Atemnus politus harbours wApol, a member of a novel supergroup S along with Wolbachia from the pseudoscorpion Cordylochernes scorpioides (wCsco). Wolbachia supergroup S is most closely related to Wolbachia supergroups C and F. Using target enrichment by hybridization with Wolbachia-specific biotinylated probes to capture large fragments of Wolbachia DNA, we produced two draft genomes of wApol. Annotation of wApol highlights presence of a biotin operon, which is incomplete in many sequenced Wolbachia genomes.

CONCLUSIONS: The present study highlights at least two symbiont acquisition events among pseudoscorpion species. Phylogenomic analysis indicates that the Wolbachia from Atemnus politus (wApol), forms a separate supergroup ("S") with the Wolbachia from Cordylochernes scorpioides (wCsco). Interestingly, the biotin operon, present in wApol, appears to have been horizontally transferred multiple times along Wolbachia evolutionary history.

RevDate: 2020-07-01
CmpDate: 2020-07-01

Suzuki K (2020)

Diversified IgA-Bacteria Interaction in Gut Homeostasis.

Advances in experimental medicine and biology, 1254:105-116.

Immunoglobulin A (IgA) is the major immunoglobulin isotype produced by the gut immune system, and many studies revealed key roles of IgA in establishing host-bacteria mutualism. This chapter will review current understandings for the function of gut IgA in regulating commensal microbiota. IgA specifically recognizes bacterial species that strongly stimulate host's immune responses, and suppresses their overgrowth or reduces the expressions of bacterial pro-inflammatory genes. On the other hand, IgA coatings on symbiotic bacteria enhance bacteria-mucus and bacteria-bacteria interactions, which induce production of metabolites enforcing mucosal barrier functions. Such diversified effects suggest that multiple factors may be involved in the mechanisms of IgA-bacteria interactions, including IgA specificity to microbial epitopes, mode of cellular responses of IgA synthesis (T-dependent and T-independent) and post-translational modifications of IgA proteins, such as glycosylation.

RevDate: 2020-07-01
CmpDate: 2020-07-01

Martignoni MM, Hart MM, Tyson RC, et al (2020)

Diversity within mutualist guilds promotes coexistence and reduces the risk of invasion from an alien mutualist.

Proceedings. Biological sciences, 287(1923):20192312.

Biodiversity is an important component of healthy ecosystems, and thus understanding the mechanisms behind species coexistence is critical in ecology and conservation biology. In particular, few studies have focused on the dynamics resulting from the co-occurrence of mutualistic and competitive interactions within a group of species. Here we build a mathematical model to study the dynamics of a guild of competitors who are also engaged in mutualistic interactions with a common partner. We show that coexistence as well as competitive exclusion can occur depending on the competition strength and on strength of the mutualistic interactions, and we formulate concrete criteria for predicting invasion success of an alien mutualist based on propagule pressure, alien traits (such as its resource exchange ability) and composition of the recipient community. We find that intra guild diversity promotes the coexistence of species that would otherwise competitively exclude each other, and makes a guild less vulnerable to invasion. Our results can serve as a useful framework to predict the consequences of species manipulation in mutualistic communities.

RevDate: 2020-07-01
CmpDate: 2020-07-01

Trevelline BK, Sosa J, Hartup BK, et al (2020)

A bird's-eye view of phylosymbiosis: weak signatures of phylosymbiosis among all 15 species of cranes.

Proceedings. Biological sciences, 287(1923):20192988.

In numerous animal clades, the evolutionary history of host species drives patterns of gut microbial community structure, resulting in more divergent microbiota with increasing phylogenetic distance between hosts. This phenomenon, termed phylosymbiosis, has been observed in diverse evolutionary lineages, but has been difficult to detect in birds. Previous tests of phylosymbiosis among birds have been conducted using wild individuals, and thus interspecific differences in diet and environment may have masked a phylogenetic signal. Therefore, we tested for phylosymbiosis among all 15 species of cranes (family Gruidae) housed in the same captive environment and maintained on identical diets. 16S rRNA sequencing revealed that crane species harbour distinct gut microbiota. Overall, we detected marginally significant patterns of phylosymbiosis, the strength of which was increased when including the estimates of absolute microbial abundance (rather than relative abundance) derived from microbial densities determined by flow cytometry. Using this approach, we detected the statistically significant signatures of phylosymbiosis only after removing male cranes from our analysis, suggesting that using mixed-sex animal cohorts may prevent the detection of phylosymbiosis. Though weak compared with mammals (and especially insects), these results provide evidence of phylosymbiosis in birds. We discuss the potential differences between birds and mammals, such as transmission routes and host filtering, that may underlie the differences in the strength of phylosymbiosis.

RevDate: 2020-07-01
CmpDate: 2020-07-01

Ibañez S, Medina MI, E Agostini (2020)

Vicia: a green bridge to clean up polluted environments.

Applied microbiology and biotechnology, 104(1):13-21.

Vicia species, commonly known as vetches, include legume plants which nowadays can be found in many countries around the world. Their use to improve soil health and productivity is crucial in management schemes that make sustainable agriculture possible, but they can also play a part in the phytoremediation of polluted environments. Furthermore, they harbor a large community of rhizospheric microorganisms, such as biodegradative bacteria and plant growth-promoting rhizobacteria, which can help to increase phytoremediation efficiency. Their mutualistic association with Rhizobium sp. has also been proposed as an attractive bioremediation tool. Thus, Vicia species could make a remarkable difference in the ecological restoration of polluted soils, thanks to their dual role as cover crops and phytoremediator plants. This mini-review discusses recent advances in the use of Vicia. Challenges and opportunities connect with the application of these species will also be revised, as well as aspects that remain to be explored.

RevDate: 2020-06-30

Rix L, Ribes M, Coma R, et al (2020)

Heterotrophy in the earliest gut: a single-cell view of heterotrophic carbon and nitrogen assimilation in sponge-microbe symbioses.

The ISME journal pii:10.1038/s41396-020-0706-3 [Epub ahead of print].

Sponges are the oldest known extant animal-microbe symbiosis. These ubiquitous benthic animals play an important role in marine ecosystems in the cycling of dissolved organic matter (DOM), the largest source of organic matter on Earth. The conventional view on DOM cycling through microbial processing has been challenged by the interaction between this efficient filter-feeding host and its diverse and abundant microbiome. Here we quantify, for the first time, the role of host cells and microbial symbionts in sponge heterotrophy. We combined stable isotope probing and nanoscale secondary ion mass spectrometry to compare the processing of different sources of DOM (glucose, amino acids, algal-produced) and particulate organic matter (POM) by a high-microbial abundance (HMA) and low-microbial abundance (LMA) sponge with single-cell resolution. Contrary to common notion, we found that both microbial symbionts and host choanocyte (i.e. filter) cells and were active in DOM uptake. Although all DOM sources were assimilated by both sponges, higher microbial biomass in the HMA sponge corresponded to an increased capacity to process a greater variety of dissolved compounds. Nevertheless, in situ feeding data demonstrated that DOM was the primary carbon source for both the LMA and HMA sponge, accounting for ~90% of their heterotrophic diets. Microbes accounted for the majority (65-87%) of DOM assimilated by the HMA sponge (and ~60% of its total heterotrophic diet) but <5% in the LMA sponge. We propose that the evolutionary success of sponges is due to their different strategies to exploit the vast reservoir of DOM in the ocean.

RevDate: 2020-06-29

Chambers SA, SD Townsend (2020)

Like mother, like microbe: human milk oligosaccharide mediated microbiome symbiosis.

Biochemical Society transactions pii:225551 [Epub ahead of print].

Starting shortly after parturition, and continuing throughout our lifetime, the gut microbiota coevolves with our metabolic and neurological programming. This symbiosis is regulated by a complex interplay between the host and environmental factors, including diet and lifestyle. Not surprisingly, the development of this microbial community is of critical importance to health and wellness. In this targeted review, we examine the gut microbiome from birth to 2 years of age to characterize the role human milk oligosaccharides play in early formation of microbial flora.

RevDate: 2020-06-30

Prado-Garcia H, Campa-Higareda A, S Romero-Garcia (2020)

Lactic Acidosis in the Presence of Glucose Diminishes Warburg Effect in Lung Adenocarcinoma Cells.

Frontiers in oncology, 10:807.

Lactic acidosis (3 to 40 mM, pH < 6.9) is a condition found in solid tumors because tumor cells have a high rate of glucose consumption and lactate production even in the presence of oxygen; nevertheless, the microenvironment might still provide a sufficient glucose supply. Lactic acidosis has been proposed to shift metabolism from aerobic glycolysis toward oxidative phosphorylation (OXPHOS). We tested if lung tumor cells cultured under lactic acidosis shift their metabolism from glycolysis to OXPHOS by consuming extracellular lactate, increasing growth rate. We analyzed lung adenocarcinoma (A-549, A-427) cell lines and non-transformed fibroblast cells (MRC-5), which were cultured using RPMI-1640 medium initially containing lactate (2 mM) and glucose (10 mM), at pH 7.2 or 6.2 and oxygen tension 21% O2 (normoxia) or 2% O2 (hypoxia). We obtained growth curves, as well as glucose consumption and lactate production rates (measured during exponential growth) for each cell line. HIF-1α (Hypoxia-inducible factor 1 α), CS (citrate synthase) and AMPK (AMP-activated protein kinase) transcript levels were analyzed using RT-qPCR. By flow cytometry, we determined: (a) expression of glucose transporters (GLUT)1 and 4; (b) lactate transporters (MCT)1 and 4; (c) cell cycle profile, and (d) protein levels of HIF-1α, total and phosphorylated AMPK (pAMPK). Mitochondrial functionality was evaluated by measuring O2 consumption in tumor cells using polarography and a Clark-type electrode. Tumor and non-transformed cells used both aerobic glycolysis and OXPHOS for obtaining energy. As of 48 h of culture, lactate levels ranged from (4.5-14 mM), thus forming a lactic environment. Lactic acidosis diminished GLUT1/GLUT4 expression and glucose consumption in A-549, but not in A-427 cells, and induced differential expression of HIF-1α, AMPK, and CS transcripts. A-427 cells increased pAMPK and HIF-1α levels and shifted their metabolism increasing OXPHOS; thus supporting cell growth. Conversely, A-549 cells increased HIF-1α protein levels, but did not activate AMPK and diminished OXPHOS. A-549 cells survived by arresting cells in G1-phase. Our findings show that lactic acidosis diminishes Warburg effect in tumor cells, but this change does not necessarily promote a shift to OXPHOS. Hence, lung adenocarcinomas show a differential metabolic response even when they are under the same microenvironmental conditions.

RevDate: 2020-06-30

Feng Y, Wu P, Fu W, et al (2020)

The Lotus japonicus Ubiquitin Ligase SIE3 Interacts With the Transcription Factor SIP1 and Forms a Homodimer.

Frontiers in plant science, 11:795.

The symbiosis receptor kinase SymRK plays an essential role in symbiotic signal transduction and nodule organogenesis. Several proteins bind to SymRK, but how the symbiosis signals are transduced from SymRK to downstream components remains elusive. We previously demonstrated that both SymRK interacting protein 1 (SIP1, an ARID-type DNA-binding protein) and SymRK interacting E3 ligase [SIE3, a RING (Really Interesting New Gene)-containing E3 ligase] interact with SymRK to regulate downstream cellular responses in Lotus japonicus during the legume-rhizobia symbiosis. Here, we show that SIE3 interacts with SIP1 in both yeast cells and Nicotiana benthamiana. SIE3 associated with itself and formed a homodimer. The cysteine 266 residue was found to be essential for SIE3 dimerization and for promoting nodulation in transgenic hairy roots of L. japonicus. Our findings provide a foundation for further investigating the regulatory mechanisms of the SymRK-mediated signaling pathway, as well as the biological function of E3 ligase dimerization in nodule organogenesis.

RevDate: 2020-06-29

Tominaga T, Yamaguchi K, Shigenobu S, et al (2020)

The effects of gibberellin on the expression of symbiosis-related genes in Paris-type arbuscular mycorrhizal symbiosis in Eustoma grandiflorum.

Plant signaling & behavior [Epub ahead of print].

Arbuscular mycorrhiza (AM) is a symbiotic interaction in terrestrial plants that is colonized by fungi in the Glomeromycotina. The morphological types of AM, including the Arum-type and Paris-type, are distinct, depending on the host plant species. A part of the regulatory pathways in Arum-type AM symbiosis has been revealed because most model plants form the Arum-type AM with a model AM fungus, Rhizophagus irregularis. Moreover, gibberellin (GA) is known to severely inhibit AM fungal colonization in Arum-type AM symbiosis. Recently, we showed that exogenous GA treatment significantly promoted AM fungal colonization in Paris-type AM symbiosis in Eustoma grandiflorum. In this study, we focused on the transcriptional changes in AM symbiosis-related genes in GA-treated E. grandiflorum. The expression levels of all examined E. grandiflorum genes were maintained or increased by GA treatment compared with those of the control treatment. Our new results suggest that signaling pathway(s) required for establishing AM symbiosis in E. grandiflorum may be distinct from the well-characterized pathway for that in model plants.

RevDate: 2020-06-29
CmpDate: 2020-06-29

Hazarika DJ, Gautom T, Parveen A, et al (2020)

Mechanism of interaction of an endofungal bacterium Serratia marcescens D1 with its host and non-host fungi.

PloS one, 15(4):e0224051.

Association of bacteria with fungi is a major area of research in infection biology, however, very few strains of bacteria have been reported that can invade and reside within fungal hyphae. Here, we report the characterization of an endofungal bacterium Serratia marcescens D1 from Mucor irregularis SS7 hyphae. Upon re-inoculation, colonization of the endobacterium S. marcescens D1 in the hyphae of Mucor irregularis SS7 was demonstrated using stereo microscopy. However, S. marcescens D1 failed to invade into the hyphae of the tested Ascomycetes (except Fusarium oxysporum) and Basidiomycetes. Remarkably, Serratia marcescens D1 could invade and spread over the culture of F. oxysporum that resulted in mycelial death. Prodigiosin, the red pigment produced by the Serratia marcescens D1, helps the bacterium to invade fungal hyphae as revealed by the increasing permeability in fungal cell membrane. On the other hand, genes encoding the type VI secretion system (T6SS) assembly protein TssJ and an outer membrane associated murein lipoprotein also showed significant up-regulation during the interaction process, suggesting the involvement of T6SS in the invasion process.

RevDate: 2020-06-30
CmpDate: 2020-06-30

Zhang T (2020)

DREPP in Nanodomains Regulates Microtubule Fragmentation during Symbiotic Infection.

The Plant cell, 32(5):1357-1358.

RevDate: 2020-06-30
CmpDate: 2020-06-30

Kaczmarek Ł, Roszkowska M, Poprawa I, et al (2020)

Integrative description of bisexual Paramacrobiotus experimentalis sp. nov. (Macrobiotidae) from republic of Madagascar (Africa) with microbiome analysis.

Molecular phylogenetics and evolution, 145:106730.

In a moss samples collected on Madagascar two populations of Paramacrobiotus experimentalis sp. nov. were found. Paramacrobiotus experimentalis sp. nov. with the presence of a microplacoid and areolatus type of eggs is similar to Pam. danielae, Pam. garynahi, Pam. hapukuensis, Pam. peteri, Pam. rioplatensis and Pam. savai, but it differs from them by some morphological and morphometric characters of the eggs. The p-distance between two COI haplotypes of Pam. experimentalis sp. nov. was 0.17%. In turn, the ranges of uncorrected genetic p-distances of all Paramacrobiotus species available in GenBank was from 18.27% (for Pam. lachowskae) to 25.26% (for Pam. arduus) with an average distance of 20.67%. We also found that Pam. experimentalis sp. nov. is bisexual. This observation was congruent on three levels: (i) morphological - specimen size dimorphism; (ii) structural (primary sexual characteristics) - females have an unpaired ovary while males have an unpaired testis and (iii) molecular - heterozygous and homozygous strains of the ITS-2 marker. Although symbiotic associations of hosts with bacteria (including endosymbiotic bacteria) are common in nature and these interactions exert various effects on the evolution, biology and reproductive ecology of hosts, there is still very little information on the bacterial community associated with tardigrades. To fill this gap and characterise the bacterial community of Pam. experimentalis sp. nov. populations and microbiome of its microhabitat, high throughput sequencing of the V3-V4 hypervariable regions in the bacterial 16S rRNA gene fragment was performed. The obtained 16S rRNA gene sequences ranged from 92,665 to 131,163. In total, 135 operational taxonomic units (OTUs) were identified across the rarefied dataset. Overall, both Pam. experimentalis sp. nov. populations were dominated by OTUs ascribed to the phylum Proteobacteria (89-92%) and Firmicutes (6-7%). In the case of samples from tardigrades' laboratory habitat, the most abundant bacterial phylum was Proteobacteria (51-90%) and Bacteroides (9-48%). In all compared microbiome profiles, only 16 of 137 OTUs were shared. We found also significant differences in beta diversity between the partly species-specific microbiome of Pam. experimentalis sp. nov. and its culturing environment. Two OTUs belonging to a putative bacterial endosymbiont were identified - Rickettsiales and Polynucleobacter. We also demonstrated that each bacterial community was rich in genes involved in membrane transport, amino acid metabolism, and carbohydrate metabolism.

RevDate: 2020-06-29
CmpDate: 2020-06-29

Jeudy S, Bertaux L, Alempic JM, et al (2020)

Exploration of the propagation of transpovirons within Mimiviridae reveals a unique example of commensalism in the viral world.

The ISME journal, 14(3):727-739.

Acanthamoeba-infecting Mimiviridae are giant viruses with dsDNA genome up to 1.5 Mb. They build viral factories in the host cytoplasm in which the nuclear-like virus-encoded functions take place. They are themselves the target of infections by 20-kb-dsDNA virophages, replicating in the giant virus factories and can also be found associated with 7-kb-DNA episomes, dubbed transpovirons. Here we isolated a virophage (Zamilon vitis) and two transpovirons respectively associated to B- and C-clade mimiviruses. We found that the virophage could transfer each transpoviron provided the host viruses were devoid of a resident transpoviron (permissive effect). If not, only the resident transpoviron originally isolated from the corresponding virus was replicated and propagated within the virophage progeny (dominance effect). Although B- and C-clade viruses devoid of transpoviron could replicate each transpoviron, they did it with a lower efficiency across clades, suggesting an ongoing process of adaptive co-evolution. We analysed the proteomes of host viruses and virophage particles in search of proteins involved in this adaptation process. This study also highlights a unique example of intricate commensalism in the viral world, where the transpoviron uses the virophage to propagate and where the Zamilon virophage and the transpoviron depend on the giant virus to replicate, without affecting its infectious cycle.

RevDate: 2020-06-29
CmpDate: 2020-06-29

Ju JF, Bing XL, Zhao DS, et al (2020)

Wolbachia supplement biotin and riboflavin to enhance reproduction in planthoppers.

The ISME journal, 14(3):676-687.

Symbiont-mediated nutritional mutualisms can contribute to the host fitness of insects, especially for those that feed exclusively on nutritionally unbalanced diets. Here, we elucidate the importance of B group vitamins in the association of endosymbiotic bacteria Wolbachia with two plant-sap feeding insects, the small brown planthopper, Laodelphax striatellus (Fallén), and the brown planthopper, Nilaparvata lugens (Stål). Infected planthoppers of both species laid more eggs than uninfected planthoppers, while the experimental transfer of Wolbachia into uninfected lines of one planthopper species rescued this fecundity deficit. The genomic analysis showed that Wolbachia strains from the two planthopper species encoded complete biosynthesis operons for biotin and riboflavin, while a metabolic analysis revealed that Wolbachia-infected planthoppers of both species had higher titers of biotin and riboflavin. Furthermore, experimental supplementation of food with a mixture of biotin and riboflavin recovered the fecundity deficit of Wolbachia-uninfected planthoppers. In addition, comparative genomic analysis suggested that the riboflavin synthesis genes are conserved among Wolbachia supergroups. Biotin operons are rare in Wolbachia, and those described share a recent ancestor that may have been horizontally transferred from Cardinium bacteria. Our research demonstrates a type of mutualism that involves a facultative interaction between Wolbachia and plant-sap feeding insects involving vitamin Bs.

RevDate: 2020-06-29
CmpDate: 2020-06-29

Ansorge R, Romano S, Sayavedra L, et al (2019)

Functional diversity enables multiple symbiont strains to coexist in deep-sea mussels.

Nature microbiology, 4(12):2487-2497.

Genetic diversity of closely related free-living microorganisms is widespread and underpins ecosystem functioning, but most evolutionary theories predict that it destabilizes intimate mutualisms. Accordingly, strain diversity is assumed to be highly restricted in intracellular bacteria associated with animals. Here, we sequenced metagenomes and metatranscriptomes of 18 Bathymodiolus mussel individuals from four species, covering their known distribution range at deep-sea hydrothermal vents in the Atlantic. We show that as many as 16 strains of intracellular, sulfur-oxidizing symbionts coexist in individual Bathymodiolus mussels. Co-occurring symbiont strains differed extensively in key functions, such as the use of energy and nutrient sources, electron acceptors and viral defence mechanisms. Most strain-specific genes were expressed, highlighting their potential to affect fitness. We show that fine-scale diversity is pervasive in Bathymodiolus sulfur-oxidizing symbionts, and hypothesize that it may be widespread in low-cost symbioses where the environment, rather than the host, feeds the symbionts.

RevDate: 2020-06-30
CmpDate: 2020-06-30

Watanabe T, Suzuki N, Tomonaga K, et al (2019)

Neo-virology: The raison d'etre of viruses.

Virus research, 274:197751.

Given that approximately 1031 virus particles exist on Earth and all of them are parasitic in living organisms, it is not hard to imagine how virus infection might affect the physiology of hosts and their ecosystems. However, traditional virology research tends to focus on viral pathogenicity or the individual pathogenic viruses; hence, the significance of viruses and viral-mediated processes in the global ecosystem has been poorly understood. To identify the previously unrecognized "raison d'etre of viruses" in nature, we established a research community, designated as the 'Neo-virology' consortium. In this consortium, we define a virus as a component of the global ecosystem and our aim is to elucidate its key roles in host organisms, that is, the intra-host ecosystem.

RevDate: 2020-06-29
CmpDate: 2020-06-29

Yu K, Pieterse CMJ, Bakker PAHM, et al (2019)

Beneficial microbes going underground of root immunity.

Plant, cell & environment, 42(10):2860-2870.

Plant roots interact with an enormous diversity of commensal, mutualistic, and pathogenic microbes, which poses a big challenge to roots to distinguish beneficial microbes from harmful ones. Plants can effectively ward off pathogens following immune recognition of conserved microbe-associated molecular patterns (MAMPs). However, such immune elicitors are essentially not different from those of neutral and beneficial microbes that are abundantly present in the root microbiome. Recent studies indicate that the plant immune system plays an active role in influencing rhizosphere microbiome composition. Moreover, it has become increasingly clear that root-invading beneficial microbes, including rhizobia and arbuscular mycorrhiza, evade or suppress host immunity to establish a mutualistic relationship with their host. Evidence is accumulating that many free-living rhizosphere microbiota members can suppress root immune responses, highlighting root immune suppression as an important function of the root microbiome. Thus, the gate keeping functions of the plant immune system are not restricted to warding off root-invading pathogens but also extend to rhizosphere microbiota, likely to promote colonization by beneficial microbes and prevent growth-defense tradeoffs triggered by the MAMP-rich rhizosphere environment.

RevDate: 2020-06-29
CmpDate: 2020-06-29

Rees DJ, Noever C, Finucci B, et al (2019)

De novo innovation allows shark parasitism and global expansion of the barnacle Anelasma squalicola.

Current biology : CB, 29(12):R562-R563.

The barnacle Anelasma squalicola is a marine epibiont found on members of the species-rich, deep-sea lantern shark family Etmopteridae (Figure 1A) but is unlike any other epibiotic thoracian barnacles [1]. While many barnacle species are associated with various marine animals including turtles and whales, with the exception of Anelasma these all retain a filter-feeding lifestyle and have a commensal relationship with their host; despite often being deeply embedded in the dermis, no other species has been reported as feeding on its host. Although Anelasma is fully equipped with cirri (thoracic appendages), these are no longer used for filter feeding [1]. Instead, Anelasma embeds a stalk with root-like structures into the flesh of the shark (Figure S1C in Supplemental Information, published with this article online) that it uses to parasitize its host. Here, we show that specimens of Anelasma sampled from all over the world show very little genetic differentiation, suggesting that this innovation coincided with a rapid worldwide expansion.

RevDate: 2020-06-30
CmpDate: 2020-06-30

Hols P, Ledesma-García L, Gabant P, et al (2019)

Mobilization of Microbiota Commensals and Their Bacteriocins for Therapeutics.

Trends in microbiology, 27(8):690-702.

With the specter of resurgence of pathogens due to the propagation of antibiotic-resistance genes, innovative antimicrobial strategies are needed. In this review, we summarize the beneficial aspects of bacteriocins, a set of miscellaneous peptide-based bacterium killers, compared with classical antibiotics, and emphasize their use in cocktails to curb the emergence of new resistance. We highlight that their prey spectrum, their molecular malleability, and their multiple modes of production might lead to specific and personalized treatments to prevent systemic disorders. Complementarily, we discuss how we might exploit prevailing bacterial commensals, such as Streptococcus salivarius, and deliberately mobilize their bacteriocin arsenal 'on site' to cure multiresistant infections or finely reshape the endogenous microbiota for prophylaxis purposes.

RevDate: 2020-06-30
CmpDate: 2020-06-30

Mazel-Sanchez B, Yildiz S, M Schmolke (2019)

Ménage à trois: Virus, Host, and Microbiota in Experimental Infection Models.

Trends in microbiology, 27(5):440-452.

Infections of mammals with pathogenic viruses occur mostly in the polymicrobial environment of mucosal surfaces or the skin. In recent years our understanding of immune modulation by the commensal microbiota has increased dramatically. The microbiota is today accepted as the prime educator and maintainer of innate and adaptive immune functions. It became further apparent that some viral pathogens profit from the presence of commensal bacteria and their metabolites, especially in the intestinal tract. We further learned that the composition and abundance of the microbiota can change as a consequence of acute and chronic viral infections. Here we discuss recent developments in our understanding of the triangular relationship of virus, host, and microbiota under experimental infection settings.

RevDate: 2020-06-27

Alemneh AA, Zhou Y, Ryder MH, et al (2020)

Mechanisms in plant growth-promoting rhizobacteria that enhance the legume-rhizobial symbiosis.

Journal of applied microbiology [Epub ahead of print].

Nitrogen fixation is an important biological process in terrestrial ecosystems and for global crop production. Legume nodulation and N2 fixation has been improved using nodule-enhancing rhizobacteria (NER) under both regular and stressed conditions. The positive effect of NER on legume-rhizobia symbiosis can be facilitated by plant growth-promoting mechanisms, some of which remain to be identified. NER that produce aminocyclopropane-1-carboxylic acid (ACC) deaminase and indoleacetic acid (IAA) enhance the legume-rhizobia symbiosis through (a) enhancing the nodule induction, (b) improving the competitiveness of rhizobia for nodulation, (c) prolonging functional nodules by suppressing nodule senescence and (d) upregulating genes associated with legume-rhizobia symbiosis. The means by which these processes enhance the legume-rhizobia symbiosis is the focus of this review. Through a better understanding of the mechanisms by which PGPR operate, and how they can be altered, will provide an opportunity to enhance legume rhizobial interactions, to provide new advances in plant growth promotion and N2 fixation.

RevDate: 2020-06-27

Sproles AE, Oakley CA, Krueger T, et al (2020)

Sub-cellular imaging shows reduced photosynthetic carbon and increased nitrogen assimilation by the non-native endosymbiont Durusdinium trenchii in the model cnidarian Aiptasia.

Environmental microbiology [Epub ahead of print].

Hosting different symbiont species can affect inter-partner nutritional fluxes within the cnidarian-dinoflagellate symbiosis. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we measured the spatial incorporation of photosynthetically-fixed 13 C and heterotrophically-derived 15 N into host and symbiont cells of the model symbiotic cnidarian Aiptasia (Exaiptasia pallida) when colonised with its native symbiont Breviolum minutum or the non-native Durusdinium trenchii. B. minutum exhibited high photosynthetic carbon assimilation per cell and translocation to host tissue throughout symbiosis establishment, while D. trenchii assimilated significantly less carbon, but obtained more host nitrogen. These findings suggest that D. trenchii has less potential to provide photosynthetically-fixed carbon to the host despite obtaining considerable amounts of heterotrophically-derived nitrogen. These sub-cellular events help explain previous observations that demonstrate differential effects of D. trenchii compared to B. minutum on the host transcriptome, proteome, metabolome, and host growth and asexual reproduction. Together, these differential effects suggest that the non-native host-symbiont pairing is sub-optimal with respect to the host's nutritional benefits under normal environmental conditions. This contributes to our understanding of the ways in which metabolic integration impacts the benefits of a symbiotic association, and the potential evolution of novel host-symbiont pairings. This article is protected by copyright. All rights reserved.

RevDate: 2020-06-27

Regaiolo A, Dominelli N, Andresen K, et al (2020)

The biocontrol agent and insect pathogen Photorhabdus luminescens interacts with plant roots.

Applied and environmental microbiology pii:AEM.00891-20 [Epub ahead of print].

Sustainable agriculture techniques are rising to improve pest management and environmental safety: biological control agents are used to enhance disease resistance and abiotic stress tolerance in crops. Here we investigated the capacity of Photorhabdus luminescens secondary variant to react to plant root exudates and its behaviour towards microorganisms in the rhizosphere. P. luminescens is known to live in symbiosis with entomopathogenic nematodes (EPNs) and to be highly pathogenic towards insects. The P. luminescens-EPNs relationship has been widely studied and used as a biological control agent, however, not much attention has been given on a putative lifestyle of P. luminescens in the rhizosphere. We performed transcriptome analysis to show how P. luminescens responds to plant root exudates. The analysis highlighted genes involved in chitin degradation, biofilm regulation, flagella formation and type VI secretion system. Furthermore, we provide evidence that P. luminescens can inhibit growth of phytopathogenic fungi. Finally, we demonstrated a specific interaction of P. luminescens with plant roots. Understanding the role and the function of this bacterium in the rhizosphere might accelerate the progress in biocontrol manipulation and elucidate the peculiar mechanisms adopted by plant growth-promoting rhizobacteria in plant roots interaction.Importance of the study Insect pathogenic Photorhabdus luminescens bacteria are widely used in biocontrol strategies against pests. Very little is known about the life of these bacteria in the rhizosphere. Here we show that P. luminescens can specifically react to and interact with plant roots. Understanding the adaptation of P. luminescens in the rhizosphere is highly important for the biotechnological application of entomopathogenic bacteria and could improve future sustainable pest management in agriculture.

RevDate: 2020-06-27

Kang W, Jiang Z, Chen Y, et al (2020)

Plant transcriptome analysis reveals specific molecular interactions between alfalfa and its rhizobial symbionts below the species level.

BMC plant biology, 20(1):293 pii:10.1186/s12870-020-02503-3.

BACKGROUND: Leguminous plants alter patterns of gene expression in response to symbiotic colonization and infection by their cognate rhizobial bacteria, but the extent of the transcriptomic response has rarely been examined below the species level. Here we describe the identification of 12 rhizobial biotypes of Ensifer meliloti, which form nitrogen-fixing nodules in the roots of alfalfa (Medicago sativa L.), followed by a comparative RNA-seq analysis of four alfalfa cultivars each inoculated with two E. meliloti strains varying in symbiotic performance and phylogenetic relatedness.

RESULTS: Rhizobial biotypes were identified on the basis of their symbiotic performance, particularly shoot dry weight. Differentially expressed genes (DEGs) and metabolic pathways were determined by comparing the RNA-seq data with that of the uninoculated control plant. Significant differences were found between DEGs generated in each cultivar with the inoculation of two rhizobial strains in comparison (P < 0.01). A total of 8111 genes was differentially expressed, representing ~ 17.1% of the M. sativa genome. The proportion of DEGs ranges from 0.5 to 12.2% for each alfalfa cultivar. Interestingly, genes with predicted roles in flavonoid biosynthesis and plant-pathogen interaction (NBS-LRR) were identified as the most significant DEGs. Other DEGs include Medsa002106 and genes encoding nodulins and NCR peptides whose expression is specifically induced during the development of nitrogen-fixing nodules. More importantly, strong significant positive correlations were observed between plant transcriptomes (DEGs and KEGG pathways) and phylogenetic distances between the two rhizobial inoculants.

CONCLUSIONS: Alfalfa expresses significantly distinct sets of genes in response to infection by different rhizobial strains at the below-species levels (i.e. biotype or strain). Candidate genes underlying the specific interactions include Medsa002106 and those encoding nodulins and NCR peptides and proteins in the NBS-LRR family.

RevDate: 2020-06-26

Fang J, Liu M, Zhang S, et al (2020)

Complex chemical signaling interactions: A bark beetle-fungus symbiotic system and host/non-host trees.

Journal of experimental botany pii:5863268 [Epub ahead of print].

The symbiosis between the bark beetle (Ips subelongatus) and its fungal symbiont (Endoconidiophora fujiensis) poses a serious threat to larch forests. However, the signaling pathways between these symbiotic partners and their host/non-host trees are not fully understood. Inoculation of the host larch (Larix principis-rupprechtii) with two strains of E. fujiensis induced a rapid and long-term release of monoterpenes. Althouh the fungi had a level of tolerance to hese compounds, many monoterpenes inhibited fungal culture growth. Moreover, monoterpenes with stronger inhibitory effects on fungal growth exhibited weaker synergistic effects on the attraction of I. subelongatus to aggregation pheromone. Surprisingly, individual isomers of aggregation pheromone components promoted fungal symbiont growth in a culture medium. Non-host volatiles (NHVs) were tested and shown to completely inhibit the growth of fungal symbionts in culture but had no effects on beetle responses to aggregation pheromone with the exception of (Z)-3-hexen-1-ol. These results reveal convergence and mutualism patterns in the evolution of I. subelongatus and E. fujiensis with respect to host tree volatiles but not in response to NHVs. Ultimately, we put forward a hypothesis that host plants are ecological and evolutionary determinants of bark beetle-fungus symbioses in terms of their complex signaling interactions.

RevDate: 2020-06-26

Jiménez-Guerrero I, Acosta-Jurado S, Medina C, et al (2020)

The Sinorhizobium fredii HH103 Type III secretion system effector NopC blocks nodulation with Lotus japonicus Gifu.

Journal of experimental botany pii:5863328 [Epub ahead of print].

The broad host-range bacterium Sinorhizobium fredii HH103 cannot nodulate the model legume Lotus japonicus Gifu. This bacterium possesses a Type III secretion system (T3SS), a specialized secretion apparatus used to deliver effector proteins (T3E) into the host cell cytosol to alter host signaling and/or suppress host defence responses to promote infection. However, some of these T3E are recognized by specific plant receptors and hence trigger a strong defence response to block infection. In rhizobia, T3E are involved in nodulation efficiency, host-range determination and, in some cases, directly activate host symbiosis signalling in a Nod factor-independent manner. In this work, we show that HH103 RifR T3SS mutants, unable to secrete T3E, gain nodulation with L. japonicus Gifu through infection threads (IT), suggesting that plant recognition of a T3E could block the infection process. To identify the T3E involved, we performed nodulation assays with a collection of mutants affected in secretion of each T3E identified in HH103 RifR so far. The nopC mutant could infect L. japonicus Gifu by IT invasion and switch the infection mechanism in L. burttii from intercellular infection to IT formation. L. japonicus gene expression analysis indicated that the infection-blocking event occurs at early stages of the symbiosis.

RevDate: 2020-06-26

Montenegro F, S Indraccolo (2020)

Metabolism in the Tumor Microenvironment.

Advances in experimental medicine and biology, 1263:1-11.

From a general perspective, in the context of solid tumors, we can distinguish metabolic alterations of cancer cells from those of the stroma. These two components interact with each other and with the extracellular matrix (ECM), and these interactions can take the form of either metabolic competition or metabolic symbiosis. The aim of this chapter is to overview the canonical metabolic alterations of tumor and stroma cells and to present specific examples of metabolic competition and symbiosis. We will also discuss the complexity and plasticity of metabolism, which pose indeed a serious threat to our ability to target selective metabolic features of tumor microenvironment with drugs. Finally, we will highlight some limitations of state-of-the-art techniques used to study tumor metabolism and propose some innovative solutions to investigate the clinical relevance of metabolic alterations for patient management and treatment.

RevDate: 2020-06-26

Doerner P (2020)

Extreme environments: crucibles of potent abiotic stress tolerance.

Journal of experimental botany, 71(13):3761-3764.

RevDate: 2020-06-26

Wang S, Chen A, Xie K, et al (2020)

Functional analysis of the OsNPF4.5 nitrate transporter reveals a conserved mycorrhizal pathway of nitrogen acquisition in plants.

Proceedings of the National Academy of Sciences of the United States of America pii:2000926117 [Epub ahead of print].

Low availability of nitrogen (N) is often a major limiting factor to crop yield in most nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi are beneficial symbionts of most land plants that enhance plant nutrient uptake, particularly of phosphate. A growing number of reports point to the substantially increased N accumulation in many mycorrhizal plants; however, the contribution of AM symbiosis to plant N nutrition and the mechanisms underlying the AM-mediated N acquisition are still in the early stages of being understood. Here, we report that inoculation with AM fungus Rhizophagus irregularis remarkably promoted rice (Oryza sativa) growth and N acquisition, and about 42% of the overall N acquired by rice roots could be delivered via the symbiotic route under N-NO3- supply condition. Mycorrhizal colonization strongly induced expression of the putative nitrate transporter gene OsNPF4.5 in rice roots, and its orthologs ZmNPF4.5 in Zea mays and SbNPF4.5 in Sorghum bicolor OsNPF4.5 is exclusively expressed in the cells containing arbuscules and displayed a low-affinity NO3- transport activity when expressed in Xenopus laevis oocytes. Moreover, knockout of OsNPF4.5 resulted in a 45% decrease in symbiotic N uptake and a significant reduction in arbuscule incidence when NO3- was supplied as an N source. Based on our results, we propose that the NPF4.5 plays a key role in mycorrhizal NO3- acquisition, a symbiotic N uptake route that might be highly conserved in gramineous species.

RevDate: 2020-06-26

Kadam SB, Pable AA, VT Barvkar (2020)

Mycorrhiza induced resistance (MIR): a defence developed through synergistic engagement of phytohormones, metabolites and rhizosphere.

Functional plant biology : FPB pii:FP20035 [Epub ahead of print].

Plants get phosphorus, water and other soil nutrients at the cost of sugar through mycorrhizal symbiotic association. A common mycorrhizal network (CMN) - a dense network of mycorrhizal hyphae - provides a passage for exchange of chemicals and signals between the plants sharing CMN. Mycorrhisation impact plants at hormonal, physiological and metabolic level and successful symbiosis also regulates ecology of the plant rhizosphere. Apart from nutritional benefits, mycorrhisation provides an induced resistance to the plants known as mycorrhiza induced resistance (MIR). MIR is effective against soil as well as foliar pathogens and pest insects. In this review, molecular mechanisms underlying MIR such as role of phytohormones, their cross talk and priming effect are discussed. Evidence of MIR against economically important pathogens and pest insects in different plants is summarised. Mycorrhiza induces many plant secondary metabolites, many of which have a role in plant defence. Involvement of these secondary metabolites in mycorrhisation and their putative role in MIR are further reviewed. Controversies about MIR are also briefly discussed in order to provide insights on the scope for research about MIR. We have further extended our review with an open ended discussion about the possibilities for transgenerational MIR.

RevDate: 2020-06-26
CmpDate: 2020-06-26

Shao SC, Wang QX, Beng KC, et al (2020)

Fungi isolated from host protocorms accelerate symbiotic seed germination in an endangered orchid species (Dendrobium chrysotoxum) from southern China.

Mycorrhiza, 30(4):529-539.

To ensure long-term survival of epiphytic orchids through active reintroduction, more research on critical life cycle stages such as seed germination and seedling establishment are needed. In this study, we used in vitro germination experiments to investigate the role of mycorrhizal fungi in determining seed germination and growth in the endangered epiphytic orchid species, Dendrobium chrysotoxum. Symbiotic seed germination experiments were conducted for 90 days under different light conditions with fungal strains isolated from protocorms of D. chrysotoxum and three sister species. Molecular analyses showed that five strains belonged to the typical orchid mycorrhizal family Tulasnellaceae, whereas the other two strains belonged to the Sebacinaceae and the genus Coprinellus. Fungal inoculation, light conditions, and their interaction had a significant effect on protocorm formation and seedling development. Three fungal isolates, including two from D. chrysotoxum and one from D. catenatum, significantly stimulated protocorm formation and seedling development under light conditions. However, fungi isolated from host protocorms (GC-14 and GC-15) produced the highest number of seedlings after 50 days (49.5 ± 8.5%, 51.3 ± 9.0%, respectively), while the fungus isolated from D. catenatum protocorms produced the maximum number of seedlings only after 90 days (48.7 ± 16.1%). To conclude, this study has shown that light conditions and the identity of fungi had a strong effect on in vitro seed germination and seedling formation in an epiphytic orchid, with fungi isolated from host protocorms leading to accelerated germination and seedling formation. Therefore, fungal source should be taken into account when using seeds and compatible fungi for seedling propagation and in situ reintroduction.

RevDate: 2020-06-26
CmpDate: 2020-06-26

Marqués-Gálvez JE, Morte A, A Navarro-Ródenas (2020)

Spring stomatal response to vapor pressure deficit as a marker for desert truffle fruiting.

Mycorrhiza, 30(4):503-512.

The cultivation of desert truffle Terfezia claveryi using Helianthemum almeriense as a host plant has recently become a solid alternative crop in the Mediterranean region due to its adaptation to arid and semiarid ecosystems, which are expected to increase during the following years because of climate change. However, management models are still being developed in order to improve and stabilize the production, which varies greatly from one year to another. According to gatherers and farmers, one of the key factors for desert truffle production is the plant phenology in spring, which, in turn, depends on environmental conditions. In this manuscript, we have characterized the physiological, morphological, and molecular responses of the mycorrhizal plants in spring, coinciding with the fructification period of the plant and fungal species. Thanks to this characterization, a sigmoidal relationship between stomatal conductance and vapor pressure deficit (VPD) was found, which can be used as a marker of plant phenological switch. In order to confirm that this phenology status is related to desert truffle fructification, this marker has been successfully correlated to total truffle production. The results of this manuscript suppose a big step forward that will help to develop management models for the desert truffle crop.

RevDate: 2020-06-26
CmpDate: 2020-06-26

Aguilar-Rodríguez J, Fares MA, A Wagner (2019)

Chaperonin overproduction and metabolic erosion caused by mutation accumulation in Escherichia coli.

FEMS microbiology letters, 366(10):.

Bacterial cells adapting to a constant environment tend to accumulate mutations in portions of their genome that are not maintained by selection. This process has been observed in bacteria evolving under strong genetic drift, and especially in bacterial endosymbionts of insects. Here, we study this process in hypermutable Escherichia coli populations evolved through 250 single-cell bottlenecks on solid rich medium in a mutation accumulation experiment that emulates the evolution of bacterial endosymbionts. Using phenotype microarrays monitoring metabolic activity in 95 environments distinguished by their carbon sources, we observe how mutation accumulation has decreased the ability of cells to metabolize most carbon sources. We study if the chaperonin GroEL, which is naturally overproduced in bacterial endosymbionts, can ameliorate the process of metabolic erosion, because of its known ability to buffer destabilizing mutations in metabolic enzymes. Our results indicate that GroEL can slow down the negative phenotypic consequences of genome decay in some environments.

RevDate: 2020-06-26
CmpDate: 2020-06-26

De Filippo C, Di Paola M, Giani T, et al (2019)

Gut microbiota in children and altered profiles in juvenile idiopathic arthritis.

Journal of autoimmunity, 98:1-12.

Microbial diversity plays a key role in the maintenance of intestinal homeostasis and in the development of the immune system in the gut mucosa. Maybe one of the most important function of our gut microbiota is the immune system education, in particular the discrimination of friends from foes that occurs during childhood. In addition to bacterial antigens, several metabolites of microbial origin have a crucial role in training of the immune system, such as Short Chain Fatty Acids (SCFAs). There are many evidences on the role of the gut microbiota in rheumatic diseases, in particular modifications of microbiota composition causing dysbiosis that, in turn, can induce gut permeability, and thus immunological imbalance and trigger inflammation. In particular, immune cells can reach extra-intestinal sites, such as joints and trigger local inflammation. Childhood is a crucial period of life for development and evolution of the gut microbiota, especially for the acquisition of fundamental functions such as immunotolerance of commensal microorganisms. For this reason, gut dysbiosis is gaining interest as a potential pathogenetic factor for Juvenile Idiopathic Arthritis (JIA). Here we summarized the studies conducted on JIA patients in which a pro-arthritogenic microbial profiles has been observed; this, together with a depletion of microbial biodiversity, clearly distinguish patients' from healthy subjects' microbiota. Further studies are however needed to better clarify the role of microbiota in JIA pathogenesis.

RevDate: 2020-06-25

Ho LH, Lee YI, Hsieh SY, et al (2020)

GeSUT4 mediates sucrose import at the symbiotic interface for carbon allocation of heterotrophic Gastrodia elata (Orchidaceae).

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

Gastrodia elata, a fully mycoheterotrophic orchid without photosynthetic ability, only grows symbiotically with the fungus Armillaria. The mechanism of carbon distribution in this mycoheterotrophy is unknown. We detected high sucrose concentrations in all stages of Gastrodia tubers, suggesting sucrose may be the major sugar transported between fungus and orchid. Thick symplasm-isolated wall interfaces in colonized and adjacent large cells implied involvement of sucrose importers. Two sucrose transporter (SUT)-like genes, GeSUT4 and GeSUT3, were identified that are highly expressed in young Armillaria-colonized tubers. Yeast complementation and isotope tracer experiments confirmed that GeSUT4 functioned as a high-affinity sucrose-specific proton-dependent importer. Plasma- membrane/tonoplast localization of GeSUT4-GFP fusions, and high RNA expression of GeSUT4 in symbiotic and large cells indicated that GeSUT4 likely functions in active sucrose transport for intercellular allocation and intracellular homeostasis. Transgenic Arabidopsis overexpressing GeSUT4 had larger leaves but were sensitive to excess sucrose and roots were colonized with fewer mutualistic Bacillus, supporting the role of GeSUT4 in regulating sugar allocation. This is not only the first documented carbon import system in a mycoheterotrophic interaction, but also highlights the evolutionary importance of sucrose transporters for regulation of carbon flow in all types of plant-microbe interactions. This article is protected by copyright. All rights reserved.

RevDate: 2020-06-25

Signorelli S, Sainz M, Tabares-da Rosa S, et al (2020)

The Role of Nitric Oxide in Nitrogen Fixation by Legumes.

Frontiers in plant science, 11:521.

The legume-rhizobia symbiosis is an important process in agriculture because it allows the biological nitrogen fixation (BNF) which contributes to increasing the levels of nitrogen in the soil. Nitric oxide (⋅NO) is a small free radical molecule having diverse signaling roles in plants. Here we present and discuss evidence showing the role of ⋅NO during different stages of the legume-rhizobia interaction such as recognition, infection, nodule development, and nodule senescence. Although the mechanisms by which ⋅NO modulates this interaction are not fully understood, we discuss potential mechanisms including its interaction with cytokinin, auxin, and abscisic acid signaling pathways. In matures nodules, a more active metabolism of ⋅NO has been reported and both the plant and rhizobia participate in ⋅NO production and scavenging. Although ⋅NO has been shown to induce the expression of genes coding for NITROGENASE, controlling the levels of ⋅NO in mature nodules seems to be crucial as ⋅NO was shown to be a potent inhibitor of NITROGENASE activity, to induce nodule senescence, and reduce nitrogen assimilation. In this sense, LEGHEMOGLOBINS (Lbs) were shown to play an important role in the scavenging of ⋅NO and reactive nitrogen species (RNS), potentially more relevant in senescent nodules. Even though ⋅NO can reduce NITROGENASE activity, most reports have linked ⋅NO to positive effects on BNF. This can relate mainly to the regulation of the spatiotemporal distribution of ⋅NO which favors some effects over others. Another plausible explanation for this observation is that the negative effect of ⋅NO requires its direct interaction with NITROGENASE, whereas the positive effect of ⋅NO is related to its signaling function, which results in an amplifier effect. In the near future, it would be interesting to explore the role of environmental stress-induced ⋅NO in BNF.

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RJR Experience and Expertise

Researcher

Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.

Educator

Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.

Administrator

Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.

Technologist

Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.

Publisher

While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.

Speaker

Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.

Facilitator

Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.

Designer

Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.

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Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

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Curriculum Vitae for R J Robbins

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