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Applied Microbiology and Biotechnology Jun 2023Microbiologically influenced corrosion is a common problem in the industrial field due to the deterioration of metals in the presence of various microorganisms, in...
Microbiologically influenced corrosion is a common problem in the industrial field due to the deterioration of metals in the presence of various microorganisms, in particular sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB). A common method to reduce microbiologically influenced corrosion is the application of biocides. The limited number of suitable biocides and the resulting development of resistance, high dosage, and high application rate hinder an effective application. An environmentally friendly alternative could be the application of antimicrobial peptides (AMP), which have already been established in the field of medical devices for a while. Here, the successful treatment of different AMPs against 3 SRB and 1 SOB was demonstrated. The peptide L5K5W was favored due to its broad activity, high stability, and simple structure resulting in low synthesis costs. An alanine scan showed that substitution of leucine with tryptophan increased the activity of this peptide twofold compared to the original peptide against D. vulgaris, the main representative of SRB. Additional optimization of this modified peptide through changes in amino acid composition and lipidations significantly increased the effectiveness, finally resulting in a minimum inhibitory concentration (MIC) of 15.63 μg/mL against Desulfovibrio vulgaris. Even against the marine SRB Desulfovibrio indonesiensis with a required salt concentration of min. 2%, an activity of the peptides can be observed (MIC: 31.25 μg/mL). The peptides also remained stable and active for 7 days in the supernatant of the bacterial culture. KEY POINTS: • Antimicrobial peptides provide an alternative to combat biocorrosive bacteria. • Optimization of the peptide sequence leads to a significant increase in activity. • The investigated peptides exhibit high stability, both in the medium and in the bacterial supernatant.
Topics: Antimicrobial Peptides; Biofilms; Desulfovibrio vulgaris; Bacteria; Disinfectants; Desulfovibrio; Corrosion
PubMed: 37154907
DOI: 10.1007/s00253-023-12562-9 -
Nature Communications Feb 2023Deep sea cold seep sediments host abundant and diverse microbial populations that significantly influence biogeochemical cycles. While numerous studies have revealed...
Deep sea cold seep sediments host abundant and diverse microbial populations that significantly influence biogeochemical cycles. While numerous studies have revealed their community structure and functional capabilities, little is known about genetic heterogeneity within species. Here, we examine intraspecies diversity patterns of 39 abundant species identified in sediment layers down to 430 cm below the sea floor across six cold seep sites. These populations are grouped as aerobic methane-oxidizing bacteria, anaerobic methanotrophic archaea and sulfate-reducing bacteria. Different evolutionary trajectories are observed at the genomic level among these physiologically and phylogenetically diverse populations, with generally low rates of homologous recombination and strong purifying selection. Functional genes related to methane (pmoA and mcrA) and sulfate (dsrA) metabolisms are under strong purifying selection in most species investigated. These genes differ in evolutionary trajectories across phylogenetic clades but are functionally conserved across sites. Intrapopulation diversification of genomes and their mcrA and dsrA genes is depth-dependent and subject to different selection pressure throughout the sediment column redox zones at different sites. These results highlight the interplay between ecological processes and the evolution of key bacteria and archaea in deep sea cold seep extreme environments, shedding light on microbial adaptation in the subseafloor biosphere.
Topics: Phylogeny; Acclimatization; Archaea; Desulfovibrio; Sulfates
PubMed: 36854684
DOI: 10.1038/s41467-023-36877-3 -
Scientific Reports Jul 2023Mediation by sulphate-reducing bacteria (SRB) is responsible for pyrite (FeS) formation. The origin of the Dachang tin polymetallic ore field is related to the...
Mediation by sulphate-reducing bacteria (SRB) is responsible for pyrite (FeS) formation. The origin of the Dachang tin polymetallic ore field is related to the mineralisation of submarine hydrothermal vent sediments. Here, we investigated SRB in these ores via morphological, chemical, and isotopic analyses. Polarised and scanning electron microscopy indicated that trace SRB fossils in the metal sulphide ore were present in the form of tubular, beaded, and coccoidal bodies comprising FeS and were enclosed within a pyrrhotite (FeS) matrix in the vicinity of micro-hydrothermal vents. The carbon (C), nitrogen (N), and oxygen (O) contents in the FeS synthesised by SRB were high, and a clear biological Raman signal was detected. No such signals were discerned in the peripheral FeS. This co-occurrence of FeS, FeS, and the remains of bacteria (probably chemoautotrophic bacteria) was interpreted as the coprecipitation process of SRB-mediated FeS formation, which has, to the best of our knowledge, not been reported before. Our study also illustrates that combined energy-dispersive X-ray spectroscopy, Raman spectroscopy, and isotopic analysis can be used as a novel methodology to document microbial-mediated processes of mineral deposition in submarine hydrothermal vent ecology on geological time scales.
Topics: Tin; China; Sulfides; Bacteria; Desulfovibrio; Sulfates
PubMed: 37468706
DOI: 10.1038/s41598-023-38827-x -
Bioelectrochemistry (Amsterdam,... Apr 2022The eutrophication of seawater is not only harmful to the environment, but also influence microbes' proliferation and then influence biocorrosion of marine engineering...
The eutrophication of seawater is not only harmful to the environment, but also influence microbes' proliferation and then influence biocorrosion of marine engineering materials to a great extent. This study investigated the microbiologically influenced corrosion (MIC) of Cu immersed in the Desulfovibrio vulgaris (a sulfate reducing bacterium) medium with four defined nutritional degrees: total nutrition, P lacking, N lacking, and P&N lacking. When D. vulgaris was cultured in more nutritional medium, more HS was generated and more serious corrosion of Cu occurred. The concentration of HS corresponding to the medium with total nutrition was as high as 4.9 × 10(±913.0) ppm. The weight loss of Cu in medium with total nutrition increased by at least 50% compared with other nutritional conditions. The depth of pitting pits on Cu increased obviously with more abundant nutrient elements N and P. The electrochemical tests supported the weight loss and also showed that an obvious passivation zone was formed on the anodic polarization curve. This indicated that a protective film was formed on the surface of Cu against uniform corrosion. The analyses of thermodynamics and experiment data indicated that metabolite MIC (M-MIC) account for the Cu corrosion by D. vulgaris.
Topics: Desulfovibrio vulgaris
PubMed: 34959026
DOI: 10.1016/j.bioelechem.2021.108040 -
MicrobiologyOpen Aug 2023In medical, environmental, and industrial processes, the accumulation of bacteria in biofilms can disrupt many processes. Antimicrobial peptides (AMPs) are receiving...
In medical, environmental, and industrial processes, the accumulation of bacteria in biofilms can disrupt many processes. Antimicrobial peptides (AMPs) are receiving increasing attention in the development of new substances to avoid or reduce biofilm formation. There is a lack of parallel testing of the effect against biofilms in this area, as well as in the testing of other antibiofilm agents. In this paper, a high-throughput screening was developed for the analysis of the antibiofilm activity of AMPs, differentiated into inhibition and removal of a biofilm. The sulfate-reducing bacterium Desulfovibrio vulgaris was used as a model organism. D. vulgaris represents an undesirable bacterium, which is considered one of the major triggers of microbiologically influenced corrosion. The application of a 96-well plate and steel rivets as a growth surface realizes real-life conditions and at the same time establishes a flexible, simple, fast, and cost-effective assay. All peptides tested in this study demonstrated antibiofilm activity, although these peptides should be individually selected depending on the addressed aim. For biofilm inhibition, the peptide DASamP1 is the most suitable, with a sustained effect for up to 21 days. The preferred peptides for biofilm removal are S6L3-33, in regard to bacteria reduction, and Bactenecin, regarding total biomass reduction.
Topics: Antimicrobial Peptides; Desulfovibrio vulgaris; Biofilms; Biomass; Corrosion
PubMed: 37642483
DOI: 10.1002/mbo3.1376 -
Applied and Environmental Microbiology Feb 2000To explore the physiological role of tetraheme cytochrome c(3) in the sulfate-reducing bacterium Desulfovibrio desulfuricans G20, the gene encoding the preapoprotein was...
To explore the physiological role of tetraheme cytochrome c(3) in the sulfate-reducing bacterium Desulfovibrio desulfuricans G20, the gene encoding the preapoprotein was cloned, sequenced, and mutated by plasmid insertion. The physical analysis of the DNA from the strain carrying the integrated plasmid showed that the insertion was successful. The growth rate of the mutant on lactate with sulfate was comparable to that of the wild type; however, mutant cultures did not achieve the same cell densities. Pyruvate, the oxidation product of lactate, served as a poor electron source for the mutant. Unexpectedly, the mutant was able to grow on hydrogen-sulfate medium. These data support a role for tetraheme cytochrome c(3) in the electron transport pathway from pyruvate to sulfate or sulfite in D. desulfuricans G20.
Topics: Amino Acid Sequence; Base Sequence; Cloning, Molecular; Conjugation, Genetic; Cytochrome c Group; Desulfovibrio; Molecular Sequence Data; Mutation; Periplasm; Plasmids; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Transcription, Genetic
PubMed: 10653734
DOI: 10.1128/AEM.66.2.671-677.2000 -
Environmental Science & Technology Jun 2019Recent studies have identified HgcAB proteins as being responsible for mercury [Hg(II)] methylation by certain anaerobic microorganisms. However, it remains...
Recent studies have identified HgcAB proteins as being responsible for mercury [Hg(II)] methylation by certain anaerobic microorganisms. However, it remains controversial whether microbes take up Hg(II) passively or actively. Here, we examine the dynamics of concurrent Hg(II) adsorption, uptake, and methylation by both viable and inactivated cells (heat-killed or starved) or spheroplasts of the sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 in laboratory incubations. We show that, without addition of thiols, >60% of the added Hg(II) (25 nM) was taken up passively in 48 h by live and inactivated cells and also by cells treated with the proton gradient uncoupler, carbonylcyanide-3-chlorophenylhydrazone (CCCP). Inactivation abolished Hg(II) methylation, but the cells continued taking up Hg(II), likely through competitive binding or ligand exchange of Hg(II) by intracellular proteins or thiol-containing cellular components. Similarly, treatment with CCCP impaired the ability of spheroplasts to methylate Hg(II) but did not stop Hg(II) uptake. Spheroplasts showed a greater capacity to adsorb Hg(II) than whole cells, and the level of cytoplasmic membrane-bound Hg(II) correlated well with MeHg production, as Hg(II) methylation is associated with cytoplasmic HgcAB. Our results indicate that active metabolism is not required for cellular Hg(II) uptake, thereby providing an improved understanding of Hg(II) bioavailability for methylation.
Topics: Desulfovibrio desulfuricans; Mercury; Methylation; Methylmercury Compounds; Sulfhydryl Compounds
PubMed: 31075193
DOI: 10.1021/acs.est.9b00047 -
ACS Chemical Biology Jul 2022Metal-dependent formate dehydrogenases are important enzymes due to their activity of CO reduction to formate. The tungsten-containing FdhAB formate dehydrogenase from...
Metal-dependent formate dehydrogenases are important enzymes due to their activity of CO reduction to formate. The tungsten-containing FdhAB formate dehydrogenase from Hildenborough is a good example displaying high activity, simple composition, and a notable structural and catalytic robustness. Here, we report the first spectroscopic redox characterization of FdhAB metal centers by EPR. Titration with dithionite or formate leads to reduction of three [4Fe-4S] clusters, and full reduction requires Ti(III)-citrate. The redox potentials of the four [4Fe-4S] centers range between -250 and -530 mV. Two distinct W signals were detected, W and W, which differ in only the -value. This difference can be explained by small variations in the twist angle of the two pyranopterins, as determined through DFT calculations of model compounds. The redox potential of W was determined to be -370 mV when reduced by dithionite and -340 mV when reduced by formate. The crystal structure of dithionite-reduced FdhAB was determined at high resolution (1.5 Å), revealing the same structural alterations as reported for the formate-reduced structure. These results corroborate a stable six-ligand W coordination in the catalytic intermediate W state of FdhAB.
Topics: Catalysis; Desulfovibrio; Desulfovibrio vulgaris; Dithionite; Electron Spin Resonance Spectroscopy; Formate Dehydrogenases; Formates; Metals; Oxidation-Reduction
PubMed: 35766974
DOI: 10.1021/acschembio.2c00336 -
Bioresource Technology Oct 2022Signaling molecules are useful in biofilm formation, but the mechanism for biofilm construction still needs to be explored. In this study, a signaling molecule,...
Signaling molecules are useful in biofilm formation, but the mechanism for biofilm construction still needs to be explored. In this study, a signaling molecule, N-butyryl-l-Homoserine lactone (C-HSL), was supplied to enhance the construction of the sulfate-reducing bacteria (SRB) bio-cathode biofilm in microbial electrolysis cell (MEC). The sulfate reduction efficiency was more than 90% in less time under the system with C-HSL addition. The analysis of SRB bio-cathode biofilms indicated that the activity, distribution, microbial population, and secretion of extracellular polymers prompted by C-HSL, which accelerate the sulfate reduction, in particular for the assimilatory sulfate reduction pathway. Specifically, the relative abundance of acidogenic fermentation bacteria increased, and Desulfovibrio was co-metabolized with acidogenic fermentation bacteria. This knowledge will help to reveal the potential of signaling molecules to enhance the SRB bio-cathode biofilm MEC construction and improve the performance of treating sulfate-containing wastewater.
Topics: Biofilms; Desulfovibrio; Electrodes; Electrolysis; Sulfates; Sulfur Oxides; Wastewater
PubMed: 35905879
DOI: 10.1016/j.biortech.2022.127695 -
The ISME Journal Nov 2020Elevated nitrate in the environment inhibits sulfate reduction by important microorganisms of sulfate-reducing bacteria (SRB). Several SRB may respire nitrate to survive...
Elevated nitrate in the environment inhibits sulfate reduction by important microorganisms of sulfate-reducing bacteria (SRB). Several SRB may respire nitrate to survive under elevated nitrate, but how SRB that lack nitrate reductase survive to elevated nitrate remains elusive. To understand nitrate adaptation mechanisms, we evolved 12 populations of a model SRB (i.e., Desulfovibrio vulgaris Hildenborough, DvH) under elevated NaNO for 1000 generations, analyzed growth and acquired mutations, and linked their genotypes with phenotypes. Nitrate-evolved (EN) populations significantly (p < 0.05) increased nitrate tolerance, and whole-genome resequencing identified 119 new mutations in 44 genes of 12 EN populations, among which six functional gene groups were discovered with high mutation frequencies at the population level. We observed a high frequency of nonsense or frameshift mutations in nitrosative stress response genes (NSR: DVU2543, DVU2547, and DVU2548), nitrogen regulatory protein C family genes (NRC: DVU2394-2396, DVU2402, and DVU2405), and nitrate cluster (DVU0246-0249 and DVU0251). Mutagenesis analysis confirmed that loss-of-functions of NRC and NSR increased nitrate tolerance. Also, functional gene groups involved in fatty acid synthesis, iron regulation, and two-component system (LytR/LytS) known to be responsive to multiple stresses, had a high frequency of missense mutations. Mutations in those gene groups could increase nitrate tolerance through regulating energy metabolism, barring entry of nitrate into cells, altering cell membrane characteristics, or conferring growth advantages at the stationary phase. This study advances our understanding of nitrate tolerance mechanisms and has important implications for linking genotypes with phenotypes in DvH.
Topics: Desulfovibrio; Desulfovibrio vulgaris; Genotype; Nitrates; Nitrogen Oxides; Oxidation-Reduction; Sulfates
PubMed: 32934357
DOI: 10.1038/s41396-020-00753-5