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Scientific Reports Nov 2020Hydrogen is a key intermediate element in microbial electrosynthesis as a mediator of the reduction of carbon dioxide (CO) into added value compounds. In the present...
Hydrogen is a key intermediate element in microbial electrosynthesis as a mediator of the reduction of carbon dioxide (CO) into added value compounds. In the present work we aimed at studying the biological production of hydrogen in biocathodes operated at - 1.0 V vs. Ag/AgCl, using a highly comparable technology and CO as carbon feedstock. Ten bacterial strains were chosen from genera Rhodobacter, Rhodopseudomonas, Rhodocyclus, Desulfovibrio and Sporomusa, all described as hydrogen producing candidates. Monospecific biofilms were formed on carbon cloth cathodes and hydrogen evolution was constantly monitored using a microsensor. Eight over ten bacteria strains showed electroactivity and H production rates increased significantly (two to eightfold) compared to abiotic conditions for two of them (Desulfovibrio paquesii and Desulfovibrio desulfuricans). D. paquesii DSM 16681 exhibited the highest production rate (45.6 ± 18.8 µM min) compared to abiotic conditions (5.5 ± 0.6 µM min), although specific production rates (per 16S rRNA copy) were similar to those obtained for other strains. This study demonstrated that many microorganisms are suspected to participate in net hydrogen production but inherent differences among strains do occur, which are relevant for future developments of resilient biofilm coated cathodes as a stable hydrogen production platform in microbial electrosynthesis.
Topics: Bacteria; Bacterial Physiological Phenomena; Bioelectric Energy Sources; Biofilms; Biosensing Techniques; Electrochemical Techniques; Hydrogen; RNA, Ribosomal, 16S; Stress, Physiological
PubMed: 33199799
DOI: 10.1038/s41598-020-76694-y -
International Journal of Dentistry 2018This study describes the biofilm formation and the corrosive capacity of sulfate-reducing bacteria (SRB) on the metallic structure of used endodontic files.
AIM
This study describes the biofilm formation and the corrosive capacity of sulfate-reducing bacteria (SRB) on the metallic structure of used endodontic files.
METHODS
Sulfate-reducing bacteria (SRB) ( oral and or environmental) were inoculated into the culture media (Postgate C culture medium or modified Postgate E culture medium). The biocorrosive potential of these bacteria will be an important component of a biopharmaceutical under development called BACCOR. Afterwards, four used endodontic files (UEFs) were separately inoculated into a specific culture media for 445 days at 30°C in an incubator. The four UEFs were placed in a scanning electron microscope (SEM) and analyzed by the energy-dispersive X-ray spectrometry (EDS).
RESULTS
The confocal laser scanning microscopic images indicate the presence of biofilm in the four samples. The SEM and SEM-EDS revealed the presence of rough, irregular structures adhering along the metallic surface of the used endodontic files, suggesting a mature calcified biofilm with a high concentration of Ca, P, C, and S.
CONCLUSION
The formation of SRB biofilms on used endodontic files shows characteristics that may contribute to the biocorrosion of these files, and the results may also provide complementary data for a biopharmaceutical, which is still under development to assist in the removal of fractured endodontic files inside root channels.
PubMed: 29861730
DOI: 10.1155/2018/8303450 -
JCI Insight Oct 2018We hypothesized that the gut microbiota influences survival of murine cardiac allografts through modulation of immunity. Antibiotic pretreated mice received vascularized...
We hypothesized that the gut microbiota influences survival of murine cardiac allografts through modulation of immunity. Antibiotic pretreated mice received vascularized cardiac allografts and fecal microbiota transfer (FMT), along with tacrolimus immunosuppression. FMT source samples were from normal, pregnant (immune suppressed), or spontaneously colitic (inflammation) mice. Bifidobacterium pseudolongum (B. pseudolongum) in pregnant FMT recipients was associated with prolonged allograft survival and lower inflammation and fibrosis, while normal or colitic FMT resulted in inferior survival and worse histology. Transfer of B. pseudolongum alone resulted in reduced inflammation and fibrosis. Stimulation of DC and macrophage lines with B. pseudolongum induced the antiinflammatory cytokine IL-10 and homeostatic chemokine CCL19 but induced lesser amounts of the proinflammatory cytokines TNFα and IL-6. In contrast, LPS and Desulfovibrio desulfuricans (D. desulfuricans), more abundant in colitic FMT, induced a more inflammatory cytokine response. Analysis of mesenteric and peripheral lymph node structure showed that B. pseudolongum gavage resulted in a higher laminin α4/α5 ratio in the lymph node cortical ridge, indicative of a suppressive environment, while D. desulfuricans resulted in a lower laminin α4/α5 ratio, supportive of inflammation. Discrete gut bacterial species alter immunity and may predict graft outcomes through stimulation of myeloid cells and shifts in lymph node structure and permissiveness.
Topics: Allografts; Animals; Anti-Bacterial Agents; Cell Line, Tumor; Colitis; Cytokines; Disease Models, Animal; Fecal Microbiota Transplantation; Female; Gastrointestinal Microbiome; Graft Rejection; Graft Survival; Heart Transplantation; Humans; Immunity, Innate; Immunosuppressive Agents; Lymph Nodes; Mice; Myocardium; Pregnancy; RAW 264.7 Cells; Tacrolimus; Treatment Outcome
PubMed: 30282817
DOI: 10.1172/jci.insight.121045 -
Environmental Science & Technology Oct 2016The disposal of elemental mercury (Hg(0)) wastes in mining and manufacturing areas has caused serious soil and groundwater contamination issues. Under anoxic conditions,...
The disposal of elemental mercury (Hg(0)) wastes in mining and manufacturing areas has caused serious soil and groundwater contamination issues. Under anoxic conditions, certain anaerobic bacteria can oxidize dissolved elemental mercury and convert the oxidized Hg to neurotoxic methylmercury. In this study, we conducted experiments with the Hg-methylating bacterium Desulfovibrio desulfuricans ND132 to elucidate the role of cellular thiols in anaerobic Hg(0) oxidation. The concentrations of cell-surface and intracellular thiols were measured, and specific fractions of D. desulfuricans ND132 were examined for Hg(0) oxidation activity and analyzed with extended X-ray absorption fine structure (EXAFS) spectroscopy. The experimental data indicate that intracellular thiol concentrations are approximately six times higher than those of the cell wall. Cells reacted with a thiol-blocking reagent were severely impaired in Hg(0) oxidation activity. Spheroplasts lacking cell walls rapidly oxidized Hg(0) to Hg(II), while cell wall fragments exhibited low reactivity toward Hg(0). EXAFS analysis of spheroplast samples revealed that multiple different forms of Hg-thiols are produced by the Hg(0) oxidation reaction and that the local coordination environment of the oxidized Hg changes with reaction time. The results of this study indicate that Hg(0) oxidation in D. desulfuricans ND132 is an intracellular process that occurs by reaction with thiol-containing molecules.
PubMed: 27654630
DOI: 10.1021/acs.est.6b03299 -
Revista Espanola de Quimioterapia :... Dec 2023
Identification of curved Gram-negative rods by MALDI-TOF mass spectrometer in a patient with Fournier ́s gangrene. A bacteremia caused by Desulfovibrio desulfuricans and Escherichia coli.
Topics: Humans; Desulfovibrio desulfuricans; Escherichia coli; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Gangrene; Bacteremia; Gram-Negative Bacteria
PubMed: 37767548
DOI: 10.37201/req/026.2023 -
Microbial Biotechnology Sep 2021Desulfovibrio desulfuricans reduces Pd(II) to Pd(0)-nanoparticles (Pd-NPs) which are catalytically active in 2-pentyne hydrogenation. To make Pd-NPs, resting cells are...
Desulfovibrio desulfuricans reduces Pd(II) to Pd(0)-nanoparticles (Pd-NPs) which are catalytically active in 2-pentyne hydrogenation. To make Pd-NPs, resting cells are challenged with Pd(II) ions (uptake), followed by addition of electron donor to promote bioreduction of cell-bound Pd(II) to Pd(0) (bio-Pd). Application of radiofrequency (RF) radiation to prepared 5 wt% bio-Pd catalyst (60 W power, 60 min) increased the hydrogenation rate by 70% with no adverse impact on selectivity to cis-2-pentene. Such treatment of a 5 wt% Pd/carbon commercial catalyst did not affect the conversion rate but reduced the selectivity. Lower-dose RF radiation (2-8 W power, 20 min) was applied to the bacteria at various stages before and during synthesis of the bio-scaffolded Pd-NPs. The reaction rate (μ mol 2-pentyne converted s ) was increased by ~threefold by treatment during bacterial catalyst synthesis. Application of RF radiation (2 or 4 W power) to resting cells prior to Pd(II) exposure affected the catalyst made subsequently, increasing the reaction rate by 50% as compared to untreated cells, while nearly doubling selectivity for cis 2-pentene. The results are discussed with respect to published and related work which shows altered dispersion of the Pd-NPs made following or during RF exposure.
Topics: Alkenes; Biological Transport; Desulfovibrio desulfuricans; Hydrogenation; Magnetic Fields
PubMed: 34216193
DOI: 10.1111/1751-7915.13878 -
Scientific Reports Jul 2017Molybdenum and tungsten are taken up by bacteria and archaea as their soluble oxyanions through high affinity transport systems belonging to the ATP-binding cassette...
Molybdenum and tungsten are taken up by bacteria and archaea as their soluble oxyanions through high affinity transport systems belonging to the ATP-binding cassette (ABC) transporters. The component A (ModA/TupA) of these transporters is the first selection gate from which the cell differentiates between MoO, WO and other similar oxyanions. We report the biochemical characterization and the crystal structure of the apo-TupA from Desulfovibrio desulfuricans G20, at 1.4 Å resolution. Small Angle X-ray Scattering data suggests that the protein adopts a closed and more stable conformation upon ion binding. The role of the arginine 118 in the selectivity of the oxyanion was also investigated and three mutants were constructed: R118K, R118E and R118Q. Isothermal titration calorimetry clearly shows the relevance of this residue for metal discrimination and oxyanion binding. In this sense, the three variants lost the ability to coordinate molybdate and the R118K mutant keeps an extremely high affinity for tungstate. These results contribute to an understanding of the metal-protein interaction, making it a suitable candidate for a recognition element of a biosensor for tungsten detection.
Topics: Amino Acid Substitution; Calorimetry; Crystallography, X-Ray; DNA Mutational Analysis; Desulfovibrio desulfuricans; Membrane Transport Proteins; Models, Molecular; Protein Conformation; Substrate Specificity; Tungsten Compounds
PubMed: 28724964
DOI: 10.1038/s41598-017-06133-y -
Microbiology Resource Announcements Aug 2019We report the complete genome sequence of the anaerobic, sulfonate-respiring, sulfate-reducing bacterium IC1. The genome was assembled into a single 3.25-Mb circular...
We report the complete genome sequence of the anaerobic, sulfonate-respiring, sulfate-reducing bacterium IC1. The genome was assembled into a single 3.25-Mb circular chromosome with 2,680 protein-coding genes identified. Sequencing of sulfonate-metabolizing anaerobes is key for understanding sulfonate degradation and its role in the sulfur cycle.
PubMed: 31371536
DOI: 10.1128/MRA.00456-19 -
Systematic and Applied Microbiology Sep 2020Two strains of sulfate-reducing bacteria (J.5.4.2-L4.2.8 and J.3.6.1-H7) were isolated from a pyrite-forming enrichment culture and were compared phylogenetically and...
Desulfolutivibrio sulfoxidireducens gen. nov., sp. nov., isolated from a pyrite-forming enrichment culture and reclassification of Desulfovibrio sulfodismutans as Desulfolutivibrio sulfodismutans comb. nov.
Two strains of sulfate-reducing bacteria (J.5.4.2-L4.2.8 and J.3.6.1-H7) were isolated from a pyrite-forming enrichment culture and were compared phylogenetically and physiologically to the closest related type strain Desulfovibrio sulfodismutans DSM 3696. The isolated strains were vibrio-shaped, motile rods that stained Gram-negative. Growth occurred from 15 to 37°C and within a pH range of 6.5-8.5. Both strains used sulfate, thiosulfate, sulfite, and dimethyl sulfoxide (DMSO) as electron acceptor when grown with lactate. Lactate was incompletely oxidized to acetate. Formate and H were used as electron donor in the presence of acetate. Dismutation of thiosulfate and pyrosulfite was observed. The two new isolates differed from D. sulfodismutans by the utilization of DMSO as electron acceptor, 82% genome-wide average nucleotide identity (ANI) and 32% digital DNA-DNA hybridization (dDDH), thus representing a novel species. The type strain of the type species Desulfovibrio desulfuricans Essex6 revealed merely 88% 16S rRNA gene identity and 49% genome-wide average amino acid identity (AAI) to the new isolates as well as to D. sulfodismutans. Furthermore, the dominance of menaquinone MK-7 over MK-6 and the dominance of ai-C fatty acids were observed not only in the two new isolated strains but also in D. sulfodismutans. Therefore, the definition of a new genus is indicated for which the name Desulfolutivibrio is proposed. We propose for strains J.5.4.2-L4.2.8 and J.3.6.1-H7 the name Desulfolutivibrio sulfoxidireducens gen. nov. sp. nov. with strain J.5.4.2-L4.2.8 defined as type strain. In addition, we propose the reclassification of Desulfovibrio sulfodismutans as Desulfolutivibrio sulfodismutans comb. nov.
Topics: Bacterial Typing Techniques; Culture Media; Desulfovibrio; Dimethyl Sulfoxide; Fatty Acids; Genes, rRNA; Genome, Bacterial; Hydrogen-Ion Concentration; Iron; Oxidation-Reduction; Phylogeny; RNA, Ribosomal, 16S; Sewage; Sulfates; Sulfides; Temperature
PubMed: 32847780
DOI: 10.1016/j.syapm.2020.126105 -
Frontiers in Bioengineering and... 2022Sulfate-reducing bacteria (SRB) catalyse the dissimilatory reduction of sulfate to hydrogen sulfide using a wide range of small molecular weight organic compounds, and...
Sulfate-reducing bacteria (SRB) catalyse the dissimilatory reduction of sulfate to hydrogen sulfide using a wide range of small molecular weight organic compounds, and hydrogen, as electron donors. Here we report the effects of different combinations of small molecular weight alcohols on the performance and bacterial composition of a moderately low pH sulfidogenic bioreactor (pH 4.0-5.5) operated at 35°C in continuous flow mode. Ethanol alone and methanol or ethanol used in combination with glycerol were evaluated based on their equivalent amounts of carbon. Although evidenced that methanol was utilised as electron donor to fuel sulfidogenesis at pH 5.5, rates of sulfate reduction/sulfide production were negatively impacted when this alcohol was first introduced to the system, though these rates increased in subsequent phases as a result of adaptation of the microbial community. Further increased dosage of methanol again caused rates of sulfidogenesis to decrease. Methanol addition resulted in perturbations of the bioreactor microbial community, and species not previously detected were present in relatively large abundance, including the sulfate-reducer . Ethanol utilization was evidenced by the increase in rates of sulfidogenesis as the dosage of ethanol increased, with rates being highest when the bioreactor was fed with ethanol alone. Concentrations of acetate in the effluent liquor also increased (up to 8 mM) as a result of incomplete oxidation of ethanol. This alcohol continued to be used as the electron donor for sulfate reduction when the bioreactor pH was decreased incrementally (to pH 4.0), but rates of sulfidogenesis decreased. The relative abundance of diminished as the bioreactor pH was lowered, while that of the acidophilic increased. This study has shown that all three alcohols can be used to fuel microbial sulfidogenesis in moderately acidic liquors, though the cost-effectiveness, availability and toxicity to the microbial community will dictate the choice of substrate.
PubMed: 36032724
DOI: 10.3389/fbioe.2022.937987