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Environmental Science & Technology Dec 2021Microbial extracellular electron transfer plays an important role in diverse biogeochemical cycles, metal corrosion, bioelectrochemical technologies, and anaerobic...
Microbial extracellular electron transfer plays an important role in diverse biogeochemical cycles, metal corrosion, bioelectrochemical technologies, and anaerobic digestion. Evaluation of electron uptake from pure Fe(0) and stainless steel indicated that, in contrast to previous speculation in the literature, and are not able to directly extract electrons from solid-phase electron-donating surfaces. grew with Fe(III) as the electron acceptor, but did not. reduced Fe(III) oxide occluded within porous alginate beads, suggesting that it released a soluble electron shuttle to promote Fe(III) oxide reduction. Conductive atomic force microscopy revealed that the pili are electrically conductive and the expression of a gene encoding an aromatics-rich putative pilin was upregulated during growth on Fe(III) oxide. The expression of genes for multi-heme -type cytochromes was not upregulated during growth with Fe(III) as the electron acceptor, and genes for a porin-cytochrome conduit across the outer membrane were not apparent in the genome. The results suggest that has adopted a novel combination of strategies to enable extracellular electron transport, which may be of biogeochemical and technological significance.
Topics: Desulfovibrio; Electron Transport; Electrons; Ferric Compounds; Geobacter; Oxidation-Reduction
PubMed: 34748326
DOI: 10.1021/acs.est.1c04071 -
Scientific Reports Sep 2018The intestinal microbiota plays a key role in the maintenance of human health. Alterations in this microbiota have been described in several autoimmune diseases,...
The intestinal microbiota plays a key role in the maintenance of human health. Alterations in this microbiota have been described in several autoimmune diseases, including nervous system diseases. Nevertheless, the information regarding neuromuscular conditions is still limited. In this study, we aimed at characterizing the intestinal microbiota composition in myasthenia gravis patients (MG). To this end fecal samples were taken from ten patients, with antibodies against the acetylcholine receptor, and ten age and sex matched controls from the same population (Asturias region, Spain). Fecal samples were submitted to microbiota analyses by 16S rRNA gene profiling, bifidobacterial ITS-region profiling and qPCR. The fecal levels of short chain fatty acids were determined by gas chromatography. MG patients were found to harbor lower relative proportions of Verrucomicrobiaceae and Bifidobacteriaceae, among others, and increased of the phylum Bacteroidetes and the family Desulfovibrionaceae. The increase of these latter microbial groups was also confirmed at quantitative level by qPCR. In contrast, no statistically significant differences were found between MG patients and the control group in the bifidobacterial population at the species level or in short chain fatty acids profiles. Our data indicates an altered fecal microbiota pattern in MG patients and point out at specific microbiota targets for intervention in this population.
Topics: Aged; Aged, 80 and over; Bacteroidetes; Bifidobacterium; Desulfovibrionaceae; Feces; Female; Gastrointestinal Microbiome; Humans; Male; Middle Aged; Myasthenia Gravis; RNA, Ribosomal, 16S; Transcriptome; Verrucomicrobia
PubMed: 30258104
DOI: 10.1038/s41598-018-32700-y -
Platinum Group Metal-free Catalysts for Hydrogen Evolution Reaction in Microbial Electrolysis Cells.Chemical Record (New York, N.Y.) Jul 2017Hydrogen gas is a green energy carrier with great environmental benefits. Microbial electrolysis cells (MECs) can convert low-grade organic matter to hydrogen gas with... (Review)
Review
Hydrogen gas is a green energy carrier with great environmental benefits. Microbial electrolysis cells (MECs) can convert low-grade organic matter to hydrogen gas with low energy consumption and have gained a growing interest in the past decade. Cathode catalysts for the hydrogen evolution reaction (HER) present a major challenge for the development and future applications of MECs. An ideal cathode catalyst should be catalytically active, simple to synthesize, durable in a complex environment, and cost-effective. A variety of noble-metal free catalysts have been developed and investigated for HER in MECs, including Nickel and its alloys, MoS , carbon-based catalysts and biocatalysts. MECs in turn can serve as a research platform to study the durability of the HER catalysts. This personal account has reviewed, analyzed, and discussed those catalysts with an emphasis on synthesis and modification, system performance and potential for practical applications. It is expected to provide insights into the development of HER catalysts towards MEC applications.
Topics: Bioelectric Energy Sources; Carbon; Catalysis; Desulfovibrio; Electrolysis; Geobacter; Hydrogen; Metals; Platinum
PubMed: 28375578
DOI: 10.1002/tcr.201700007 -
BMC Microbiology Dec 2021Bilophila wadsworthia, a strictly anaerobic, sulfite-reducing bacterium and common member of the human gut microbiota, has been associated with diseases such as...
BACKGROUND
Bilophila wadsworthia, a strictly anaerobic, sulfite-reducing bacterium and common member of the human gut microbiota, has been associated with diseases such as appendicitis and colitis. It is specialized on organosulfonate respiration for energy conservation, i.e., utilization of dietary and host-derived organosulfonates, such as taurine (2-aminoethansulfonate), as sulfite donors for sulfite respiration, producing hydrogen sulfide (HS), an important intestinal metabolite that may have beneficial as well as detrimental effects on the colonic environment. Its taurine desulfonation pathway involves the glycyl radical enzyme (GRE) isethionate sulfite-lyase (IslAB), which cleaves isethionate (2-hydroxyethanesulfonate) into acetaldehyde and sulfite.
RESULTS
We demonstrate that taurine metabolism in B. wadsworthia 3.1.6 involves bacterial microcompartments (BMCs). First, we confirmed taurine-inducible production of BMCs by proteomic, transcriptomic and ultra-thin sectioning and electron-microscopical analyses. Then, we isolated BMCs from taurine-grown cells by density-gradient ultracentrifugation and analyzed their composition by proteomics as well as by enzyme assays, which suggested that the GRE IslAB and acetaldehyde dehydrogenase are located inside of the BMCs. Finally, we are discussing the recycling of cofactors in the IslAB-BMCs and a potential shuttling of electrons across the BMC shell by a potential iron-sulfur (FeS) cluster-containing shell protein identified by sequence analysis.
CONCLUSIONS
We characterized a novel subclass of BMCs and broadened the spectrum of reactions known to take place enclosed in BMCs, which is of biotechnological interest. We also provided more details on the energy metabolism of the opportunistic pathobiont B. wadsworthia and on microbial HS production in the human gut.
Topics: Bacterial Proteins; Bilophila; Cell Compartmentation; Gastrointestinal Microbiome; Gene Expression Profiling; Humans; Hydrogen Sulfide; Isethionic Acid; Proteomics; Sulfites; Taurine
PubMed: 34903181
DOI: 10.1186/s12866-021-02386-w -
Scientific Reports Jul 2017Surface nanopatterning of metals has been an effective technique for improved performance and functionalization. However, it is of great challenge to fabricate...
Surface nanopatterning of metals has been an effective technique for improved performance and functionalization. However, it is of great challenge to fabricate nanostructure on carbon steels despite their extensive use and urgent needs to maintain the performance reliability and durability. Here, we report a one-step anodization technique to nanopattern a carbon steel in 50 wt.% NaOH solution for highly effective anti-adhesion by sulphate reducing bacteria (SRB), i.e., Desulfovibrio desulfuricans subsp. desulfuricans (Beijerinck) Kluyver and van Niel. We characterize the morphology, structure, composition, and surface roughness of the nanostructured film formed on the steel as a function of anodizing potential. We quantify the surface hydrophobicity by contact angle measurements, and the SRB adhesion by fluorescent analysis. The optimal anodization potential of 2.0 V is determined for the best performance of anti-adhesion of SRB to the steel, resulting in a 23.5 times of reduction of SRB adhesion compared to bare steel. We discuss the mechanisms for the film formation on the steel during anodization, and the high-performance anti-adhesion of bacteria to nanopatterned steels. Our technique is simple, cost-effective and environment-friendly, providing a promising alternative for industry-scale surface nanopatterning of carbon steels for effective controlling of bacterial adhesion.
Topics: Bacterial Adhesion; Desulfovibrio desulfuricans; Hydrophobic and Hydrophilic Interactions; Nanotubes, Carbon; Steel; Surface Properties
PubMed: 28706204
DOI: 10.1038/s41598-017-05626-0 -
Applied and Environmental Microbiology Apr 2024Sulfate-reducing prokaryotes (SRPs) are essential microorganisms that play crucial roles in various ecological processes. Even though SRPs have been studied for over a... (Review)
Review
Sulfate-reducing prokaryotes (SRPs) are essential microorganisms that play crucial roles in various ecological processes. Even though SRPs have been studied for over a century, there are still gaps in our understanding of their biology. In the past two decades, a significant amount of data on SRP ecology has been accumulated. This review aims to consolidate that information, focusing on SRPs in soils, their relation to the rare biosphere, uncultured sulfate reducers, and their interactions with other organisms in terrestrial ecosystems. SRPs in soils form part of the rare biosphere and contribute to various processes as a low-density population. The data reveal a diverse range of sulfate-reducing taxa intricately involved in terrestrial carbon and sulfur cycles. While some taxa like and are well studied, others are more enigmatic. For example, members of the Acidobacteriota phylum appear to hold significant importance for the terrestrial sulfur cycle. Many aspects of SRP ecology remain mysterious, including sulfate reduction in different bacterial phyla, interactions with bacteria and fungi in soils, and the existence of soil sulfate-reducing archaea. Utilizing metagenomic, metatranscriptomic, and culture-dependent approaches will help uncover the diversity, functional potential, and adaptations of SRPs in the global environment.
Topics: Ecosystem; Bacteria; Desulfovibrio; Sulfates; Sulfur; Soil
PubMed: 38551370
DOI: 10.1128/aem.01390-23 -
FEMS Microbiology Letters Mar 2020Short and branched chain fatty acid kinases participate in both bacterial anabolic and catabolic processes, including fermentation, through the reversible, ATP-dependent...
Short and branched chain fatty acid kinases participate in both bacterial anabolic and catabolic processes, including fermentation, through the reversible, ATP-dependent synthesis of acyl phosphates. This study reports biochemical properties of a predicted butyrate kinase from Desulfovibrio vulgaris str. Hildenborough (DvBuk) expressed heterologously and purified from Escherichia coli. Gel filtration chromatography indicates purified DvBuk is active as a dimer. The optimum temperature and pH for DvBuk activity is 44°C and 7.5, respectively. The enzyme displays enhanced thermal stability in the presence of substrates as observed for similar enzymes. Measurement of kcat and KM for various substrates reveals DvBuk exhibits the highest catalytic efficiencies for butyrate, valerate and isobutyrate. In particular, these measurements reveal this enzyme's apparent high affinity for C4 fatty acids relative to other butyrate kinases. These results have implications on structure and function relationships within the ASKHA superfamily of phosphotransferases, particularly regarding the acyl binding pocket, as well as potential physiological roles for this enzyme in Desulfovibrio vulgaris str. Hildenborough.
Topics: Chromatography, Gel; Desulfovibrio vulgaris; Enzyme Stability; Escherichia coli; Hydrogen-Ion Concentration; Phosphotransferases (Carboxyl Group Acceptor); Recombinant Proteins; Structure-Activity Relationship; Temperature
PubMed: 32166312
DOI: 10.1093/femsle/fnaa047 -
MBio Jan 2021Formation of multispecies communities allows nearly every niche on earth to be colonized, and the exchange of molecular information among neighboring bacteria in such...
Formation of multispecies communities allows nearly every niche on earth to be colonized, and the exchange of molecular information among neighboring bacteria in such communities is key for bacterial success. To clarify the principles controlling interspecies interactions, we previously developed a coculture model with two anaerobic bacteria, (Gram positive) and Hildenborough (Gram negative, sulfate reducing). Under conditions of nutritional stress for , the existence of tight cell-cell interactions between the two bacteria induced emergent properties. Here, we show that the direct exchange of carbon metabolites produced by allows to duplicate its DNA and to be energetically viable even without its substrates. We identify the molecular basis of the physical interactions and how autoinducer-2 (AI-2) molecules control the interactions and metabolite exchanges between and (or and ). With nutrients, produces a small molecule that inhibits the AI-2 activity and could act as an antagonist Sensing of AI-2 by could induce formation of an intercellular structure that allows directly or indirectly metabolic exchange and energetic coupling between the two bacteria. Bacteria have usually been studied in single culture in rich media or under specific starvation conditions. However, in nature they coexist with other microorganisms and build an advanced society. The molecular bases of the interactions controlling this society are poorly understood. Use of a synthetic consortium and reducing complexity allow us to shed light on the bacterial communication at the molecular level. This study presents evidence that quorum-sensing molecule AI-2 allows physical and metabolic interactions in the synthetic consortium and provides new insights into the link between metabolism and bacterial communication.
Topics: Clostridium acetobutylicum; Coculture Techniques; Culture Media; DNA Replication; DNA, Bacterial; Desulfovibrio vulgaris; Energy Metabolism; Fluoresceins; Genes, Reporter; Homoserine; Lactones; Luminescent Proteins; Quorum Sensing; Signal Transduction; Red Fluorescent Protein
PubMed: 33468690
DOI: 10.1128/mBio.02758-20 -
Archives of Microbiology May 2022Bacteria are important participants in sulfur cycle of the extremely haloalkaline environment, e.g. soda lake. The effects of physicochemical factors on the composition...
Bacteria are important participants in sulfur cycle of the extremely haloalkaline environment, e.g. soda lake. The effects of physicochemical factors on the composition of sulfide-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) in soda lake have remained elusive. Here, we surveyed the community structure of total bacteria, SOB and SRB based on 16S rRNA, soxB and dsrB gene sequencing, respectively, in five soda lakes with different physicochemical factors. The results showed that the dominant bacteria belonged to the phyla Proteobacteria, Bacteroidetes, Halanaerobiaeota, Firmicutes and Actinobacteria. SOB and SRB were widely distributed in lakes with different physicochemical characteristics, and the community composition were different. In general, salinity and inorganic nitrogen sources (NH-N, NO-N) were the most significant factors. Specifically, the communities of SOB, mainly including Thioalkalivibrio, Burkholderia, Paracoccus, Bradyrhizobium, and Hydrogenophaga genera, were remarkably influenced by the levels of NH-N and salinity. Yet, for SRB communities, including Desulfurivibrio, Candidatus Electrothrix, Desulfonatronospira, Desulfonatronum, Desulfonatronovibrio, Desulfonatronobacter and so on, the most significant determinants were salinity and NO-N. Besides, Rhodoplanes played a significant role in the interaction between SOB and SRB. From our results, the knowledge regarding the community structures of SOB and SRB in extremely haloalkaline environment was extended.
Topics: Bacteria; Desulfovibrio; Humans; Lakes; Oxidation-Reduction; Phylogeny; RNA, Ribosomal, 16S; Salinity; Sulfides; Sulfur
PubMed: 35567694
DOI: 10.1007/s00203-022-02925-7 -
FEMS Microbiology Ecology Jul 2023Arsenic (As) and antimony (Sb) from mining sites can seep into aquatic ecosystems by acid mine drainage (AMD). Here, the possibility of concomitantly removing As and Sb...
Arsenic (As) and antimony (Sb) from mining sites can seep into aquatic ecosystems by acid mine drainage (AMD). Here, the possibility of concomitantly removing As and Sb from acidic waters by precipitation of sulfides induced by sulfate-reducing bacteria (SRB) was investigated in a fixed-bed column bioreactor. The real AMD water used to feed the bioreactor contained nearly 1 mM As, while the Sb concentrations were increased (0.008 ± 0.006 to 1.01 ± 0.07 mM) to obtain an Sb/As molar ratio = 1. Results showed that the addition of Sb did not affect the efficiency of As bio-precipitation. Sb was removed efficiently (up to 97.9% removal) between the inlet and outlet of the bioreactor, together with As (up to 99.3% removal) in all conditions. Sb was generally removed as it entered the bioreactor. Appreciable sulfate reduction occurred in the bioreactor, which could have been linked to the stable presence of a major SRB operational taxonomic unit affiliated with the Desulfosporosinus genus. The bacterial community included polymer degraders, fermenters, and acetate degraders. Results suggested that sulfate reduction could be a suitable bioremediation process for the simultaneous removal of Sb and As from AMD.
Topics: Arsenic; Antimony; Sulfates; Ecosystem; Desulfovibrio; Bioreactors; Water Pollutants, Chemical
PubMed: 37407427
DOI: 10.1093/femsec/fiad075