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Biochemistry Sep 2023Nickel-substituted rubredoxin (NiRd) from has previously been shown to act as both a structural and functional mimic of the [NiFe] hydrogenase. However, improvements...
Nickel-substituted rubredoxin (NiRd) from has previously been shown to act as both a structural and functional mimic of the [NiFe] hydrogenase. However, improvements both in turnover frequency and overpotential are needed to rival the native [NiFe] hydrogenase enzymes. Characterization of a library of NiRd mutants with variations in the secondary coordination sphere suggested that protein dynamics played a substantial role in modulating activity. In this work, rubredoxin scaffolds were selected from diverse organisms to study the effects of distal sequence variation on catalytic activity. It was found that though electrochemical catalytic activity was only slightly impacted across the series, the Rd sequence from a psychrophilic organism exhibited substantially higher levels of solution-phase hydrogen production. Additionally, Eyring analyses suggest that catalytic activation properties relate to the growth temperature of the parent organism, implying that the general correlation between the parent organism environment and catalytic activity often seen in naturally occurring enzymes may also be observed in artificial enzymes. Selecting protein scaffolds from hosts that inhabit diverse environments, particularly low-temperature environments, represents an alternative approach for engineering artificial metalloenzymes.
Topics: Hydrogenase; Rubredoxins; Catalysis; Oxidation-Reduction
PubMed: 37579005
DOI: 10.1021/acs.biochem.3c00249 -
Journal of Hazardous Materials Oct 2023Sulfate-reducing bacteria (SRB) were effective in stabilizing Sb. However, the influence of electron donors and acceptors during SRB remediation, as well as the...
Sulfate-reducing bacteria (SRB) were effective in stabilizing Sb. However, the influence of electron donors and acceptors during SRB remediation, as well as the ecological principles involved, remained unclear. In this study, Desulfovibrio desulfuricans ATCC 7757 was utilized to stabilize soil Sb within microcosm. Humic acid (HA) or sodium sulfate (NaSO) were employed to enhance SRB capacity. The SRB+HA treatment exhibited the highest Sb stabilization rate, achieving 58.40%. Bacterial community analysis revealed that SRB altered soil bacterial diversity, community composition, and assembly processes, with homogeneous selection as the predominant assembly processes. When HA and NaSO significantly modified the stimulated microbial community succession trajectories, shaped the taxonomic composition and interactions of the bacterial community, they showed converse effect in shaping bacterial community which were both helpful for promoting dissimilatory sulfate reduction. NaSO facilitated SRB-mediated anaerobic reduction and promoted interactions between SRB and bacteria involved in nitrogen and sulfur cycling. The HA stimulated electron generation and storage, and enhanced the interactions between SRB and bacteria possessing heavy metal tolerance or carbohydrate degradation capabilities.
Topics: Antimony; Oxidation-Reduction; Soil; Biological Availability; Desulfovibrio; Bacteria; Sulfates
PubMed: 37567138
DOI: 10.1016/j.jhazmat.2023.132256 -
Journal of Hazardous Materials Oct 2023This paper describes a unique molecular mechanism for the EPS-mediated synthesis of CdS QDs by sulfate-reducing bacteria (SRB) under carbon source-induced reinforcement....
This paper describes a unique molecular mechanism for the EPS-mediated synthesis of CdS QDs by sulfate-reducing bacteria (SRB) under carbon source-induced reinforcement. Under the induced by carbon sources (HCOONa, CHCOONa and CHO), there was a significant increase in EPS production of SRB, particularly in protein, and the capacity of Cd(II) adsorption was further enhanced. CdS QDs were extracellularly synthesized by adding S after Cd(II) adsorption. The results showed that CdS QDs were wrapped or adhered by EPS, and the most significant increase in Arg and Lys among basic amino acids in EPS after HCOONa-induced was 133.34% and 63.89%, respectively. This may serve as a biological template for QD synthesis, producing protein gels with a large number of microcavities and controlling the nucleation of CdS QDs. The highest yield of HCOONa-CdS was achieved after induction, with 23.59 g/g biomass per unit strain, which was 447.34% higher than that before induction and was at a high level in previous studies. The synthesized CdS QDs were uniform in size distribution and had higher luminescence activity and a larger specific surface area than those synthesized by the chemical synthesis route, provides a new idea for EPS treatment of heavy metal wastewater and metal biorecovery.
Topics: Cadmium; Desulfovibrio desulfuricans; Carbon; Metals, Heavy; Desulfovibrio
PubMed: 37499495
DOI: 10.1016/j.jhazmat.2023.132146 -
Emerging Infectious Diseases Aug 2023An 84-year-old man in Japan who had undergone endovascular aortic repair 9 years earlier had an infected aneurysm develop. We detected Desulfovibrio desulfuricans MB at...
An 84-year-old man in Japan who had undergone endovascular aortic repair 9 years earlier had an infected aneurysm develop. We detected Desulfovibrio desulfuricans MB at the site. The patient recovered after surgical debridement, artificial vessel replacement, and appropriate antimicrobial therapy. Clinicians should suspect Desulfovibrio spp. infection in similar cases.
Topics: Male; Humans; Aged, 80 and over; Desulfovibrio desulfuricans; Aneurysm; Japan
PubMed: 37486321
DOI: 10.3201/eid2908.230403 -
Bioelectrochemistry (Amsterdam,... Oct 2023Effect of exogenous riboflavin on sulfate-reducing bacteria (SRB) corrosion of a spirally welded joint (WJ) of X80 steel was investigated by SEM/EDS, XPS, 3D ultra-depth...
Effect of exogenous riboflavin on sulfate-reducing bacteria (SRB) corrosion of a spirally welded joint (WJ) of X80 steel was investigated by SEM/EDS, XPS, 3D ultra-depth microscopy and electrochemical measurements. The main style of SRB corrosion of the WJ is local corrosion. The local corrosion sensitivity of the heating affected zone (HAZ) of the WJ was always lower than that of the weld zone (WZ) and base metal (BM) in all the SRB-inoculated mediums. SRB corrosion of the WJ is selective. With the dosage increase of riboflavin, the selective pitting corrosion of the WJ becomes more pronounced.
Topics: Desulfovibrio desulfuricans; Biofilms; Corrosion; Desulfovibrio; Steel; Riboflavin
PubMed: 37235890
DOI: 10.1016/j.bioelechem.2023.108469 -
Chemosphere Jul 2023Heap leaching ionic rare earth tailings might be prone to nourish sulfate reducing bacteria (SRB), but the SRB community in terrestrial ecosystems, such as tailings, has...
Heap leaching ionic rare earth tailings might be prone to nourish sulfate reducing bacteria (SRB), but the SRB community in terrestrial ecosystems, such as tailings, has never been studied. This work was conducted to investigate the SRB communities in revegetated and bare tailings in Dingnan county, Jiangxi province, China, incorporating with indoor experiments to isolate SRB strain in bioremediation of Cd contamination. Significant increases in richness, accompanied by reductions in evenness and diversity, were found in the SRB community in revegetated tailings compared to bare tailings. At genus taxonomic level, two distinct dominant SRB were observed in samples from bare and revegetated tailings, with Desulfovibrio dominating in the former and Streptomyces dominating in the latter, respectively. A single SRB strain was screened out from the bare tailings (REO-01). The cell of REO-01 was rod-shaped and belonged to family Desulfuricans and genus Desulfovibrio. The Cd resistance of the strain was further examined, no changes in cell morphology were observed at 0.05 mM Cd, additionally, the atomic ratios of S, Cd, and Fe changed with the increase in Cd dosages, indicating FeS and CdS were produced simultaneously, XRD results further confirmed the production changed gradually from FeS to CdS with increasing Cd dosages from 0.05 to 0.2 mM. FT-IR analysis showed that functional groups containing amide, polysaccharide glycosidic linkage, hydroxyl, carboxy, methyl, phosphodiesters and sulfhydryl groups in extracellular polymeric substances (EPS) of REO-01 might have affinity with Cd. This study demonstrated the potential of a single SRB strain isolated from ionic rare earth tailings in bioremediation of Cd contamination.
Topics: Cadmium; Biodegradation, Environmental; Ecosystem; Spectroscopy, Fourier Transform Infrared; Sulfates; Desulfovibrio; Metals, Rare Earth
PubMed: 37023895
DOI: 10.1016/j.chemosphere.2023.138615 -
Microorganisms Jan 2023belongs to Sulfate-reducing bacteria (SRB), which are widely present in anaerobic environments, including the human gut. has been associated with many human diseases,...
belongs to Sulfate-reducing bacteria (SRB), which are widely present in anaerobic environments, including the human gut. has been associated with many human diseases, including chronic liver disease. However, the characteristics and difference of from fecal samples of healthy volunteers (HV) and patients with liver cirrhosis (LC) have not been fully elucidated. Here, we isolated from the feces of 6 HV and 9 LC, and 88 strains were obtained. In the feces of HV, 55% of isolated strains were , followed by (15%), D. (11%), (9%), (4%), (4%) and (2%). However, only (60%) and (40%) were isolated from fecal samples of patients with LC. Our results suggest that there was a significant difference in the desulfurization ability and the HS production ability of different . . Furthermore, we found that isolated from the patients with LC generally had a higher hydrogen sulfide production capacity, gastrointestinal tolerance, and levels of antibiotic resistance than the same species isolated from HV. Our findings suggested that may be associated with the occurrence and development of liver cirrhosis.
PubMed: 36838242
DOI: 10.3390/microorganisms11020276 -
Biomedicines Nov 2022Chronic diarrhea is associated with enteric dysbiosis and provokes the overuse of antibiotics. Fecal microbiota transplantation (FMT) is a promising therapy, but it...
Chronic diarrhea is associated with enteric dysbiosis and provokes the overuse of antibiotics. Fecal microbiota transplantation (FMT) is a promising therapy, but it shows discrepant clinical efficacy. Bacterial colonization in recipients has been studied, although little is known about the role of gut fungi and Archaea after FMT. In this study, we evaluated the efficacy of human-derived FMT on spontaneous chronic diarrhea cynomolgus monkeys and revealed the effector mechanisms. We demonstrated that FMT can mitigate the appearance of diarrheal symptoms and inhibit the increase in interleukin-6, interleukin-8, interleukin-1β, and interferon-γ and the decrease in interleukin-10 in serum. We confirmed that FMT restored the disturbance of gut bacteria by reducing the relative abundances of potential pathogens, including 5_2_54FAA, and 21_3, and increasing the levels of and CAG_367 in diarrheal monkeys. The metabolic pathways of healthy and FMT monkeys' gut bacteria were enriched in amino acid metabolism, carbohydrate metabolism, and lipid metabolism, while the metabolic pathways of pre-FMT monkeys' gut bacteria were enriched in antibiotic production. Moreover, a higher Ascomycota/Basidiomycota ratio, higher levels, and lower abundance were present in intestinal fungi after FMT. Although the abundance of the Archaea did not change significantly, it was inversely correlated with the anti-inflammatory factor IL-4 after FMT. These results support the further development and application of FMT for chronic diarrhea.
PubMed: 36551772
DOI: 10.3390/biomedicines10123016 -
New Biotechnology Dec 2022A range of Desulfovibrio spp. can reduce metal ions to form metallic nanoparticles that remain attached to their surfaces. The bioreduction of palladium (Pd) has been...
A range of Desulfovibrio spp. can reduce metal ions to form metallic nanoparticles that remain attached to their surfaces. The bioreduction of palladium (Pd) has been given considerable attention due to its extensive use in areas of catalysis and electronics and other technological domains. In this study we report, for the first time, evidence for Pd(II) reduction by the highly corrosive Desulfovibrio ferrophilus IS5 strain to form surface attached Pd nanoparticles, as well as rapid formation of Pd(0) coated microbial nanowires. These filaments reached up to 8 µm in length and led to the formation of a tightly bound group of interconnected cells with enhanced ability to attach to a low carbon steel surface. Moreover, when supplied with high concentrations of Pd (≥ 100 mmol Pd(II) g dry cells), both Desulfovibrio desulfuricans and D. ferrophilus IS5 formed bacteria/Pd hybrid porous microstructures comprising millions of cells. These three-dimensional structures reached up to 3 mm in diameter with a dose of 1200 mmol Pd(II) g dry cells. Under suitable hydrodynamic conditions during reduction, two-dimensional nanosheets of Pd metal were formed that were up to several cm in length. Lower dosing of Pd(II) for promoting rapid synthesis of metal coated nanowires and enhanced attachment of cells onto metal surfaces could improve the efficiency of various biotechnological applications such as microbial fuel cells. Formation of biologically stimulated Pd microstructures could lead to a novel way to produce metal scaffolds or nanosheets for a wide variety of applications.
Topics: Palladium; Desulfovibrio desulfuricans; Desulfovibrio; Catalysis
PubMed: 36396027
DOI: 10.1016/j.nbt.2022.11.001 -
Chinese Medicine Oct 2022As a first-line chemotherapeutic agent, 5-fluorouracil (5-FU) exhibits many side effects, weakening its efficacy in cancer treatment. In this study, we hypothesize that...
BACKGROUND
As a first-line chemotherapeutic agent, 5-fluorouracil (5-FU) exhibits many side effects, weakening its efficacy in cancer treatment. In this study, we hypothesize that Poria cocos polysaccharides (PCP), a traditional Chinese herbal medicine with various bioactivities and prebiotic effects, might improve the therapeutic effect of 5-FU by restoring the homeostasis of the gut microenvironment and the commensal gut microflora.
METHODS
Apc mice were employed to evaluate the anti-cancer effect of 5-FU in conjunction with PCP treatment. Body weight and food consumption were monitored weekly. Polyp count was used to assess the anti-cancer effect of PCP and 5-FU. Expressions of mucosal cytokines and gut epithelial junction molecules were measured using qRT-PCR. 16S rRNA gene sequencing of fecal DNAs was used to evaluate the compositional changes of gut microbiota (GM). Transplantation of Lactobacillus johnsonii and Bifidobacterium animalis were performed to verify the prebiotic effects of PCP in improving the efficacy of 5-FU.
RESULTS
The results showed that PCP treatment alleviated the weight loss caused by 5-FU treatment and reduced the polyp burden in Apc mice. Additionally, PCP treatment eased the cytotoxic effects of 5-FU by reducing the expressions of pro-inflammatory cytokines, increasing the anti-inflammatory cytokines; and significantly improving the gut barriers by enhancing the tight junction proteins and associated adhesion molecules. Furthermore, 16S rRNA gene sequencing data showed that PCP alone or with 5-FU could stimulate the growth of probiotic bacteria (Bacteroides acidifaciens, Bacteroides intestinihominis, Butyricicoccus pullicaecorum, and the genera Lactobacillus, Bifidobacterium, Eubacterium). At the same time, it inhibited the growth of potential pathogens (e.g., Alistipes finegoldii, Alistipes massiliensis, Alistipes putredinis., Citrobacter spp., Desulfovibrio spp., and Desulfovibrio desulfuricans). Moreover, the results showed that transplantation of L.johnsonii and B.animalis effectively reduced the polyp burden in Apc mice being treated with 5-FU.
CONCLUSION
Our study showed that PCP could effectively improve the anti-cancer effect of 5-FU by attenuating its side effects, modulating intestinal inflammation, improving the gut epithelial barrier, and modulating the gut microbiota of Apc mice.
PubMed: 36192796
DOI: 10.1186/s13020-022-00667-8