Project description:Microbiome and transcriptomic analysis of cathodic biofilms of MEC and anaerobic granular sludge of an UASB, with DNA and RNA extraction
Project description:The gene expression profile of wild-type Desulfovibrio vulgaris grown on cathodic hydrogen, generated at an iron electrode surface with an imposed negative potential of -1.1 V (cathodic protection conditions). The gene expression profile of cells grown on cathodic hydrogen was compared to that of cells grown with gaseous hydrogen bubbling through the culture. Relative to the latter, the electrode-grown cells over-expressed two hydrogenases, the hyn1 genes for [NiFe] hydrogenase-1, and the hyd genes, encoding [Fe] hydrogenase. The hmc genes for the high molecular weight cytochrome (Hmc) complex, which allows electron flow from the hydrogenases across the cytoplasmic membrane, were also over-expressed. In contrast, cells grown on gaseous hydrogen over-expressed the hys genes for [NiFeSe] hydrogenase. Cells growing on the electrode also over-expressed genes encoding proteins which promote biofilm formation. Although the gene expression profiles for these two modes of growth were distinct, they were more closely related to each other than to that for cells grown in a lactate- and sulfate-containing medium. Electrochemically measured corrosion rates were lower for iron electrodes covered with hyn1-, hyd-, and hmc-mutant biofilms, as compared to wild-type biofilms. This confirms the importance, suggested by the gene expression studies, of the corresponding gene products in D. vulgaris-mediated iron corrosion. Keywords: Growth on Iron Electrode and Biofilm formation For each condition 2 unique biological samples were hybridized to 4 arrays that each contained duplicate spots. Genomic DNA was used as universal reference.
Project description:The gene expression profile of wild-type Desulfovibrio vulgaris grown on cathodic hydrogen, generated at an iron electrode surface with an imposed negative potential of -1.1 V (cathodic protection conditions). The gene expression profile of cells grown on cathodic hydrogen was compared to that of cells grown with gaseous hydrogen bubbling through the culture. Relative to the latter, the electrode-grown cells over-expressed two hydrogenases, the hyn1 genes for [NiFe] hydrogenase-1, and the hyd genes, encoding [Fe] hydrogenase. The hmc genes for the high molecular weight cytochrome (Hmc) complex, which allows electron flow from the hydrogenases across the cytoplasmic membrane, were also over-expressed. In contrast, cells grown on gaseous hydrogen over-expressed the hys genes for [NiFeSe] hydrogenase. Cells growing on the electrode also over-expressed genes encoding proteins which promote biofilm formation. Although the gene expression profiles for these two modes of growth were distinct, they were more closely related to each other than to that for cells grown in a lactate- and sulfate-containing medium. Electrochemically measured corrosion rates were lower for iron electrodes covered with hyn1-, hyd-, and hmc-mutant biofilms, as compared to wild-type biofilms. This confirms the importance, suggested by the gene expression studies, of the corresponding gene products in D. vulgaris-mediated iron corrosion. Keywords: Growth on Iron Electrode and Biofilm formation
