Project description:Geobacter sulfurreducens PCA was put under selective pressure for rapid Fe(III) oxide reduction. The resultant strain, V1, contained five confirmed mutations and reduced Fe(III) oxide 17 times faster. Whole genome DNA microarray analysis was performed in order to determine which genes are up- or down-regulated in V1 compared to PCA, both grown with ferric citrate as an electron acceptor.
Project description:This SuperSeries is composed of the following subset Series: GSE22497: Transcriptome analysis of Geobacter sulfurreducens under multiple growth conditions GSE22503: ChIP-chip of Geobacter sulfurreducens PCA with antibody against RNAP and RpoD under various conditions GSE22511: Genome-wide transcription start site determination of Geobacter sulfurreducens under multiple growth conditions Refer to individual Series
Project description:The effects of increasing addition of green tea in dietary changes the bacterial populations in broiler ileum were evaluated. Four hundreds of AA broilers were randomly assigned to four groups with green tea addition of 0, 0.5, 1 and 2 percent in the diet. The body weight showed no difference but a digital increase positively correlated with addition of green tea. The content of green tea had a linear effect of lengthening the ileum villi. The barcoded DNA pyrosequencing method was used to reveal 15 phyla, 1157phylotypes and 3098 16S operational taxonomic units (OTUs). The most predominant bacterial phyla were Firmicutes (56.89%), Actinobacteria (30.58%), Proteobacteria (8.61%) and Bacteroidetes (2.72%). As the proportion of additional green tea increased, the abundance of phylum Actinobacteria (p=0.003) and Proteobacteria (p=0.049) almost linearly increased, while the proportion of Firmicutes (p=0.027) linearly decreased. Only 2 OTUs were significantly affected by the increased additive, Corynebacteriaceae (p=0.011) and Staphylococcaceae (p= 0.006). Triplot analysis suggested that the dominant phyla of Verrucomicrobia, TM7 and Actinobacteria were clearly related to the addition of green tea. Moreover, green tea addition influenced the construction of microbiota, and lengthened the villus in ileum by Monte Carlo permutation test. These findings provide a new understanding of the ileal microbial ecology, which may be useful in modulating the gut microbiome, and also the proper usage of powdered green tea.
Project description:Geobacter sulfurreducens PCA was put under selective pressure for rapid Fe(III) oxide reduction. The resultant strain, V1, contained five confirmed mutations and reduced Fe(III) oxide 17 times faster. Whole genome DNA microarray analysis was performed in order to determine which genes are up- or down-regulated in V1 compared to PCA, both grown with ferric citrate as an electron acceptor. Three biological replicates were hybridized in duplicate. Experimental (V1) was labeled with cy5, control (wild type PCA) was labeled with cy3.
Project description:In this study, we investigated Mn3+-cycling microbial populations enriched from Lake Matano, Indonesia using metagenomics and metaproteomics. Lake Matano contains an active Mn cycle that links the oxic-anoxic interface with anoxic deep waters that are enriched in iron and manganese, and depleted in sulfate, phosphate, and oxidized nitrogen (Crowe et al., 2008; Jones et al., 2011). Sediments were incubated with sequential transfers for ~1 year with Mn3+ as the sole electron acceptor and methane as organic carbon until achieving sediment-free conditions. Here we investigate this novel species of Dechloromonas (Betaproteobacteria), “Candidatus Dechloromonas occultata,” which was the dominant population in enrichment cultures with active Mn3+ reduction. “Ca. D. occultata” expressed electron conduits related to those involved in Fe2+ oxidation (Mto-like), as well as a novel cytochrome c-rich gene cluster putatively involved in extracellular electron transfer, and an atypical nitrous oxide reductase. According to ribosomal counts, Dechloromonas outnumber Geobacter. In terms of functional genes, Dechloromonas expresses a wider variety and number of genes. Dechloromonas therefore seems to have a (selective?) advantage over Geobacter. Previous experiments revealed that Dechloromonas express nitrogen regulators, reductases and scavenging genes, as well as many carbon central metabolic pathways, and aromatic carbon degradation pathways. Dechloromonas is a beta proteobacteria, and these are "experts" in nitrogen metabolism. Geobacter, on the other hand, is well known for carbon degradation. Our previous experiments lead to our hypothesis that Dechloromonas is more active because they are more successful at acquiring nitrogen, a limiting nutrient for Geobacter. This would further suggest that carbon is not the limiting nutrient. We will test 2 hypotheses with the next suite of experiments 1) pyrophosphate supports the community, by allowing carbon fixation , 2)Dechloromonas has a (selective?) advantage over Geobacter. To test this hypothesis, bioreactors will be used to grow biotriplicate cultures of (1)- CH4 vs. pyrophosphate and (2)-CH4 vs. Mn(III) pyrophosphate. Here we have analyzed whole cell pellets using gas phase fractionations on the Q Exactive. Are Dechloromonas capable of out-competing Geobacter when grown in media with methane as the only carbon source bioreactors because they are capable of acquiring more nitrogen? Source of inoculum. Lake Matano is a metal-rich, ancient ocean analog (Crowe et al. 2011, Jones et al. 2011). Organic carbon in Lake Matano is mostly mineralized via methanogenesis before reaching the iron-rich sediments, limiting organic matter bioavailability for metal-reducers (Kuntz et al. 2015). A 15-cm sediment core from 200 m water depth in Lake Matano, Sulawesi Island, Indonesia (02°26′27.1′′S, 121°15′12.3′′E; in situ sediment temperature ~27°C) was sampled in November 2014 and sub-sampled at 5 cm increments. Sediments were sealed in gas-tight Mylar bags with no headspace (Hansen et al. 2000) and stored at 4°C until incubations began in December 2015.