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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 -
Journal of Nanoparticle Research : An... 2015Early studies have focused on the synthesis of palladium nanoparticles within the periplasmic layer or on the outer membrane of and on the S-layer protein of . However,...
Early studies have focused on the synthesis of palladium nanoparticles within the periplasmic layer or on the outer membrane of and on the S-layer protein of . However, it has remained unclear whether the synthesis of palladium nanoparticles also takes place in the bacterial cell cytoplasm. This study reports the use of high-resolution scanning transmission electron microscopy with a high-angle annular dark field detector and energy dispersive X-ray spectrometry attachment to investigate the intracellular synthesis of palladium nanoparticles (Pd NPs). We show the intracellular synthesis of Pd NPs within cells of two anaerobic strains of and an aerobic strain of using hydrogen and formate as electron donors. The Pd nanoparticles were small and largely monodispersed, between 0.2 and 8 nm, occasionally from 9 to 12 nm with occasional larger nanoparticles. With NCIMB 8307 (but not . NCIMB 8326) and with NCIMB 12555, the NPs were larger when made at the expense of formate, co-localizing with phosphate in the latter, and were crystalline, but were amorphous when made with H with no phosphorus association. The intracellular Pd nanoparticles were mainly icosahedrons with surfaces comprising {111} facets and about 5 % distortion when compared with that of bulk palladium. The particles were more concentrated in the cell cytoplasm than the cell wall, outer membrane, or periplasm. We provide new evidence for synthesis of palladium nanoparticles within the cytoplasm of bacteria, which were confirmed to maintain cellular integrity during this synthesis.
PubMed: 27004043
DOI: 10.1007/s11051-015-3067-5 -
Molecular Microbiology Dec 2016In silico analyses identified a Crp/Fnr family transcription factor (HcpR) in sulfate-reducing bacteria that controls expression of the hcp gene, which encodes the...
In silico analyses identified a Crp/Fnr family transcription factor (HcpR) in sulfate-reducing bacteria that controls expression of the hcp gene, which encodes the hybrid cluster protein and contributes to nitrosative stress responses. There is only one hcpR gene in the model sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough, but two copies in Desulfovibrio desulfuricans 27774, which can use nitrate as an alternative electron acceptor to sulfate. Structures of the D. desulfuricans hcpR1, hcpR2 and hcp operons are reported. We present evidence that hcp expression is regulated by HcpR2, not by HcpR1, and that these two regulators differ in both their DNA-binding site specificity and their sensory domains. HcpR1 is predicted to be a b-type cytochrome. HcpR1 binds upstream of the hcpR1 operon and its synthesis is regulated coordinately with hcp in response to NO. In contrast, hcpR2 expression was not induced by nitrate, nitrite or NO. HcpR2 is an iron-sulfur protein that reacts with NO and O . We propose that HcpR1 and HcpR2 use different sensory mechanisms to regulate subsets of genes required for defense against NO-induced nitrosative stress, and that diversification of signal perception and DNA recognition by these two proteins is a product of D. desulfuricans adaptation to its particular environmental niche.
Topics: Amino Acid Sequence; Bacterial Proteins; Computational Biology; Computer Simulation; Desulfovibrio desulfuricans; Iron-Sulfur Proteins; Nitrates; Nitrites; Nitrosation; Operon; Transcription Factors
PubMed: 27671526
DOI: 10.1111/mmi.13540 -
Canadian Journal of Microbiology Sep 2018Growth of two dissimilatory sulfate-reducing bacteria, Desulfosporosinus orientis (gram-positive) and Desulfovibrio desulfuricans (gram-negative), in a chemically...
Growth of two dissimilatory sulfate-reducing bacteria, Desulfosporosinus orientis (gram-positive) and Desulfovibrio desulfuricans (gram-negative), in a chemically defined culture medium resulted in similar growth rates (doubling times for each culture = 2.8 h) and comparable rates of HS generation (D. orientis = 0.19 nmol/L S per cell per h; D. desulfuricans = 0.12 nmol/L S per cell per h). Transmission electron microscopy of whole mounts and thin sections revealed that the iron sulfide mineral precipitates produced by the two cultures were morphologically different. The D. orientis culture flocculated, with the minerals occurring as subhedral plate-like precipitates, which nucleated on the cell wall during exponential growth producing extensive mineral aggregates following cell autolysis and endospore release. In contrast, the D. desulfuricans culture produced fine-grained colloidal or platy iron sulfide precipitates primarily within the bulk solution. Mineral analysis by scanning electron microscopy - energy dispersive spectroscopy indicated that neither culture promoted advanced mineral development beyond a 1:1 Fe:S stoichiometry. This analysis did not detect pyrite (FeS). The average Fe:S ratios were 1 : 1.09 ± 0.03 at 24 h and 1 : 1.08 ± 0.03 at 72 h for D. orientis and 1 : 1.05 ± 0.02 at 24 h and 1 : 1.09 ± 0.07 at 72 h for D. desulfuricans. The formation of "biogenic" iron sulfides by dissimilatory sulfate-reducing bacteria is influenced by bacterial cell surface structure, chemistry, and growth strategy, i.e., mineral aggregation occurred with cell autolysis of the gram-positive bacterium.
Topics: Bacteriolysis; Cell Wall; Desulfovibrio desulfuricans; Iron; Minerals; Oxidation-Reduction; Peptococcaceae; Sulfates; Sulfides
PubMed: 30169128
DOI: 10.1139/cjm-2017-0545 -
The Science of the Total Environment Sep 2018The removals of heavy metals and sulfate in the synthetic acid mine drainages (AMDs) by Desulfovibrio desulfuricans, sulfate-reducing bacteria (SRB), and the indigenous...
The removals of heavy metals and sulfate in the synthetic acid mine drainages (AMDs) by Desulfovibrio desulfuricans, sulfate-reducing bacteria (SRB), and the indigenous bacteria isolated from the mine area soil sample were studied to compare the AMD treatment efficiencies. The AMD treatment by the D. desulfuricans grown in the Desulfovibrio medium was used to represent bioaugmentation, while the AMD treatment by the indigenous bacteria grown in the Desulfovibrio medium was used to represent biostimulation. The consumption of lactate and sulfate suggested that the zinc (Zn) removal in the Zn-spiked Desulfovibrio medium by D. desulfuricans involved chemical precipitation and biosorption. The complete Zn removal by D. desulfuricans took 24 h, while the indigenous bacteria took 360 h. The significantly lower rate can probably be attributed to the composition of the culture. The removal of Zn in the sulfate-rich synthetic AMD-containing Desulfovibrio medium (i.e., AMD) was adversely affected by the presence of other heavy metals. Also, the sulfate reduction by D. desulfuricans and the indigenous bacteria was reduced from 47% to 20% and from 36% to 6%, respectively. The inhibitive effects on the removal of heavy metals and sulfate were greater with the Zn/Cu-spiked AMD than the Zn-spiked AMD. Overall, the indigenous bacteria showed potential for removing heavy metals and sulfate in AMDs, while the removal efficiency was lower than D. desulfuricans. The continuous supply of carbon sources with an adaptation period may be required to enhance the AMD treatment efficiency by the indigenous bacteria.
Topics: Bacteria; Biodegradation, Environmental; Desulfovibrio desulfuricans; Metals, Heavy; Mining; Sulfates; Water Pollutants, Chemical
PubMed: 29710584
DOI: 10.1016/j.scitotenv.2018.04.231 -
Biometals : An International Journal on... Oct 2019Sulfate-reducing bacteria have been suggested to have an etiological role in the development of inflammatory bowel diseases and ulcerative colitis in humans....
Sulfate-reducing bacteria have been suggested to have an etiological role in the development of inflammatory bowel diseases and ulcerative colitis in humans. Traditionally. bismuth compounds have been administered to alleviate gastrointestinal discomfort and disease symptoms. One mechanism by which this treatment occurs is through binding bacterial derived hydrogen sulfide in the intestines. With the addition of bismuth-deferiprone, bismuth-citrate and bismuth subsalicylate to reactions containing cells of D. desulfuricans ATCC 27774, the oxidation of H with sulfate as the electron acceptor was inhibited but H oxidation with nitrate, nitrite and sulfite was not reduced. Our research suggests that a target for bismuth inhibition of D. desulfuricans is the F subunit of the ATP synthase and, thus, dissimilatory sulfate reduction does not occur. At sublethal concentrations, bismuth as Bi(III) is precipitated by hydrogen sulfide produced from respiratory sulfate reduction by D. desulfuricans. Nanocrystals of bismuth sulfide were determined to be BiS through the use of high resolution transmission electron microscopy imaging with X-ray energy-dispersive spectroscopy analysis. In the absence of sulfate, D. desulfuricans oxidizes H with the reduction of Bi(III) to Bi and this was also established by X-ray energy-dispersive spectroscopy analysis.
Topics: Adenosine Triphosphatases; Anaerobiosis; Bismuth; Desulfovibrio desulfuricans; Microbial Sensitivity Tests; Nanoparticles
PubMed: 31549273
DOI: 10.1007/s10534-019-00213-4 -
Gut Microbes 2024Diet is a key player in gut-liver axis. However, the effect of different dietary patterns on gut microbiota and liver functions remains unclear. Here, we used rodent...
Diet is a key player in gut-liver axis. However, the effect of different dietary patterns on gut microbiota and liver functions remains unclear. Here, we used rodent standard chow and purified diet to mimic two common human dietary patterns: grain and plant-based diet and refined-food-based diet, respectively and explored their impacts on gut microbiota and liver. Gut microbiota experienced a great shift with notable increase in , gut bile acid (BA) levels elevated significantly, and liver inflammation was observed in mice fed with the purified diet. Liver inflammation and elevated gut BA levels also occurred in mice fed with the chow diet after receiving ATCC 29,577 (DSV). Restriction of sulfur-containing amino acids (SAAs) prevented liver injury mainly through higher hepatic antioxidant and detoxifying ability and reversed the elevated BA levels due to excess . fermentation of human fecal microbiota with primary BAs demonstrated that DSV enhanced production of secondary BAs. Higher concentration of both primary and secondary BAs were found in the gut of germ-free mice after receiving DSV. In conclusion, Restriction of SAAs in diet may become an effective dietary intervention to prevent liver injury associated with excess in the gut.
Topics: Animals; Gastrointestinal Microbiome; Mice; Liver; Humans; Desulfovibrio; Male; Mice, Inbred C57BL; Bile Acids and Salts; Amino Acids; Diet; Feces; Sulfur; Amino Acids, Sulfur
PubMed: 38935546
DOI: 10.1080/19490976.2024.2370634 -
Acta Chimica Slovenica Mar 2022The present work investigates on anodisation of aluminium in 1.0 M sodium oxalate and methodically evaluates the influence of zirconium silicate as an additive. The...
The present work investigates on anodisation of aluminium in 1.0 M sodium oxalate and methodically evaluates the influence of zirconium silicate as an additive. The effect of additive upon structure, morphology, micro hardness and composition of the coating formed under various anodising conditions has been examined comprehensively. The surface of the coating was modified by stearic acid and its immersion time was optimized. The dependence of surface morphology, kinetic parameters, and microstructural characteristics of the coating on electrolyte /additive concentration, anodising time, and the temperature has also been inspected. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) combined with EDAX studies indicates the beneficial role of zirconium silicate towards the formation of crystalline coating with improved corrosion-resistant characteristics. The static water contact angle on the surface-modified coatings was 122° ± 0.4°. This contact angle of super hydrophobic coating has been improved by KOH treatment (152.76o ± 0.4°) which is obtained under optimized conditions exhibit the corrosion resistance (1.68 × 108 Ω cm-1)which is nearly 8 times higher than that of bare aluminium (8.36 × 101 Ω cm-1). The efficacies of the surface-modified coatings against bacteria that are commonly encountered in marine (Desulfovibrio desulfuricans) and medical applications (Staphylococcus aureus and Escherichia coli) are also demonstrated.
Topics: Corrosion; Hydrophobic and Hydrophilic Interactions; Silicates; Zirconium
PubMed: 35298023
DOI: 10.17344/acsi.2021.6519 -
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 -
Nature Communications Oct 2020Six CO fixation pathways are known to operate in photoautotrophic and chemoautotrophic microorganisms. Here, we describe chemolithoautotrophic growth of the...
Six CO fixation pathways are known to operate in photoautotrophic and chemoautotrophic microorganisms. Here, we describe chemolithoautotrophic growth of the sulphate-reducing bacterium Desulfovibrio desulfuricans (strain G11) with hydrogen and sulphate as energy substrates. Genomic, transcriptomic, proteomic and metabolomic analyses reveal that D. desulfuricans assimilates CO via the reductive glycine pathway, a seventh CO fixation pathway. In this pathway, CO is first reduced to formate, which is reduced and condensed with a second CO to generate glycine. Glycine is further reduced in D. desulfuricans by glycine reductase to acetyl-P, and then to acetyl-CoA, which is condensed with another CO to form pyruvate. Ammonia is involved in the operation of the pathway, which is reflected in the dependence of the autotrophic growth rate on the ammonia concentration. Our study demonstrates microbial autotrophic growth fully supported by this highly ATP-efficient CO fixation pathway.
Topics: Adenosine Triphosphate; Ammonia; Autotrophic Processes; Bacterial Proteins; Carbon Dioxide; Desulfovibrio desulfuricans; Gene Expression Profiling; Genome, Bacterial; Glycine; Metabolomics
PubMed: 33037220
DOI: 10.1038/s41467-020-18906-7