Project description:Dissimilatory sulfate reduction (DSR) mediated by sulfate-reducing microorganisms (SRMs) plays a pivotal role in global sulfur, carbon, oxygen, and iron cycles since ~3.5 billion years ago. The canonical DSR pathway is believed to be sulfate reduction to sulfide. Herein, we report a new DSR pathway in phylogenetically diverse SRMs through which zero-valent sulfur (ZVS) is directly generated. We identified that approximately 8.9% of sulfate reduction was directed toward ZVS with S8 as a predominant product, and the ratio of sulfate-to-ZVS could be changed with SRMs’ growth conditions, particularly the medium salinity. Further coculturing experiments and metadata analyses revealed that DSR-derived ZVS supported the growth of various ZVS-metabolizing microorganisms, highlighting this new pathway as an essential component of the sulfur biogeochemical cycle
Project description:The effect of nitrate reduction (anaerobic cultivation in the presence of heme, vitamin K2 and nitrate) was compared with anaerobic cultivation supplemented with citrate (Lactobacillus plantarum). The medium was chemically defined medium with mannitol as main carbon source Two-condition experiment, nitrate vs citrate reducing cells. Biological replicates: 4 nitrate reducing cultures, 4 citrate reducing cultures, independently grown and harvested. Two slides were used, each slide contained 8 Arrays. Citrate reducing cultures are called reactor 1-4, Nitrate reducing cultures are called reactor A-D
Project description:The sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough possesses four periplasmic hydrogenases to facilitate the oxidation of molecular hydrogen. These include an [Fe], a [NiFeSe] and two [NiFe] hydrogenases encoded by the hyd, hys, hyn1 and hyn2 genes, respectively. In order to understand their cellular functions the expression levels of these hydrogenases, along with the growth rate analysis of mutant strains, was determined during growth on defined media under 3 different conditions. These conditions incuded lactate or hydrogen at either 5% or 50% (vol/vol) used as the sole electron donor for sulfate reduction. Keywords: Electron donor change
Project description:The sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough possesses four periplasmic hydrogenases to facilitate the oxidation of molecular hydrogen. These include an [Fe], a [NiFeSe] and two [NiFe] hydrogenases encoded by the hyd, hys, hyn1 and hyn2 genes, respectively. In order to understand their cellular functions the expression levels of these hydrogenases, along with the growth rate analysis of mutant strains, was determined during growth on defined media under 3 different conditions. These conditions incuded lactate or hydrogen at either 5% or 50% (vol/vol) used as the sole electron donor for sulfate reduction. Keywords: Electron donor change For each condition 2 unique biological samples were hybridized to 4 arrays that each contained duplicate spots. Genomic DNA was used as universal reference. After total intensity normalization the SAM (significance analysis of microarrays) was used to find differentially expressed genes.
Project description:Sulfate-reducing bacteria (SRB) colonize the guts of ~50% of humans. We used genome-wide transposon mutagenesis and insertion-site sequencing (INSeq), RNA-Seq, plus mass spectrometry to characterize genetic and environmental factors that impact the niche of Desulfovibrio piger, the most common SRB in a surveyed cohort of healthy USA adults. Gnotobiotic mice were colonized with an assemblage of sequenced human gut bacterial species with or without D. piger and fed diets with different levels and types of carbohydrates and sulfur sources. Diet was a major determinant of functions expressed by this artificial 9-member community and of the genes that impact D. piger fitness; the latter includes high- and low-affinity systems for utilizing ammonia, a limiting resource for D. piger in mice consuming a polysaccharide-rich diet. While genes involved in hydrogen consumption and sulfate reduction are necessary for its colonization, varying dietary free sulfate levels did not significantly alter levels of D. piger, which can obtain sulfate from the host in part via cross-feeding mediated by Bacteroides-encoded sulfatases. Chondroitin sulfate, a common dietary supplement, increased D. piger and H2S levels without compromising gut barrier integrity. A chondroitin sulfate-supplemented diet together with D. piger impacted the assemblage’s substrate utilization preferences, allowing consumption of more reduced carbon sources, and increasing the abundance of the H2-producing Actinobacterium, Collinsella aerofaciens. Our findings provide genetic and metabolic details of how this H2-consuming SRB shapes the responses of a microbiota to diet ingredients, and a framework for examining how individuals lacking D. piger differ from those that harbor it. 8 samples total, 2 gropus of 4 mice: Proximal colon gene expression profiles of gnotobiotic mice colonized with an artificial gut community composed of 8 human gut species (group 1: NoDp) and from mice colonized with the same community plus D. piger (Dp). Mice were fed a HF/HS diet supplemented with 3% chondroitin sulfate. Animals were sacrificed 2 weeks after colonization
