Ontology highlight
ABSTRACT:
PROVIDER: PRJNA891906 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:The formation of electroactive biofilms is a crucial process for the generation of bioelectricity and bioremediation. G. sulfurreducens is a dissimilatory metal-reducing microorganism that can couple oxidation of organic matter with extracellular electron transfer to different insoluble electron acceptors. It has the capability to form biofilms in insoluble metal oxides and electroconductive biofilms in electrodes in bioelectrochemical systems. The formation of electroactive biofilms in this microorganism is a process that has been studied from a physiological, genetic, physical, and electrochemical approach. In G. sulfurreducens, we found that the transcriptional regulator GSU1771 participates in the gene expression of essential genes involved in electron transfer and biofilm formation. Strains deficient in GSU1771 increases Fe(III) reduction, produces more c-type cytochromes and exopolysaccharides. Furthermore, the biofilms produced are thicker and more electroactive than wild-type. In this work, we investigate the global gene expression profile performing RNA-seq comparing Δgsu1771 mutant biofilm grown in non-conductive support (glass) and respiring-graphite electrode. RNA-seq analysis of Δgsu1771 biofilm grown in glass support revealed a total of 467 (167 upregulated and 300 downregulated) differentially expressed genes versus the wild-type biofilm. Meanwhile, in Δgsu1771 biofilm developed in respiring-electrode graphite, we detect 119 (79 upregulated and 40 downregulated) differentially expressed genes with respect to wild-type biofilm. Moreover, transcriptional changes of 67 (56 with the same regulation and in 11 counterregulation) genes were shared in Δgsu1771 biofilm developed in glass and graphite electrodes. We locate upregulated in Δgsu1771 biofilms potential target genes, involved in exopolysaccharide synthesis (gsu1961-63, gsu1959, gsu1972-73, gsu1976-77). We confirmed the upregulation of gsu1979, gsu0972, gsu0783, pgcA, omcM, aroG, panC gnfK, gsu2507, and the downregulation of asnA, ato-1, gsu0810, pilA, csrA, ppcD, and gsu3356 genes by RT-qPCR. DNA-protein binding assay shows direct binding of the GSU1771 regulator to the promoter region of pgcA, pulF, relA, and gsu3356. Also, heme-staining and western blotting revealed an increase of c-type cytochromes in Δgsu1771 biofilms such as OmcS and OmcZ. In general, our data shows that GSU1771 is a global regulator involved in controlling the extracellular electron transfer and exopolysaccharide synthesis, processes required for electroconductive biofilm development.
2023-06-19 | GSE223184 | GEO
Project description:Microbial extracellular electron uptake (EEU) is central to bioelectrochemical processes and biocorrosion, yet its molecular mechanisms remain incompletely understood. Here, we investigate how excess Fe2+ modulates EEU in Desulfovibrio ferrophilus IS5, a strain that causes severe anaerobic iron corrosion via outer-membrane cytochromes (OMCs)-mediated electron uptake. We show that IS5 grown with elevated Fe2+ exhibits substantially enhanced EEU. This enhancement arises through two complementary mechanisms: (i) increased abundance of functional OMCs via upregulation of a cytochrome assembly protein, and (ii) an additional electron transfer route mediated by FeS nanoparticles precipitated on the IS5 outer membrane. Remarkably, IS5 with low OMCs expression but biosynthesized FeS can rapidly shift to EEU before OMCs induction. These findings suggest that during iron corrosion, when IS5 cells are embedded within thick corrosion crusts and biofilms and face both high Fe2+ concentrations and organic limitation, they exploit OMCs and FeS nanoparticles in parallel to sustain high-rate EEU from iron. This study advances the mechanistic understanding of EEU-driven iron corrosion and highlights a potential avenue for manipulating bioelectrochemical systems.
2026-03-24 | GSE313310 | GEO