Analysis of the iron stimulon and fur regulon of Geobacter sulfurreducens [expression]
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ABSTRACT: G. sulfurreducens was cultured on a variety of different iron concentrations and differential expression analysis was used to identify the iron stimulon. Wild type G. sulfurreducens was cultured on fresh water media with trace concentrations of iron (iron sufficient condition) as well as no trace iron (iron deficient condition). It was also cultured in ferric citrate (iron excess condition) media
Project description:Fur is a transcriptional regulator whose activity is dependent on Fe(II) concentrations. Chromatin immunoprecipitation (ChIP) coupled to microarray analysis allowed for the identification of Fur binding sites within the G. sulfurreducens genome. Wild type G. sulfurreducnes was cultured on fresh water media (harvested during log phase), and ChIP was used to identify Fur binding regions.
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:We applied a ChIP-chip approach to elucidate the binding profiles of RNAP and RpoD experimentally under different growth conditions. This technique localizes DNA fragments within DNA-protein complexes enriched by chromatin immunoprecipitation using high-density oligonucleotide tilling arrays. A 21 ChIP-chip study using immunoprecipitated DNA (IP-DNA) from three culture conditions for RNAP and four culture conditions for RpoD. The high-density oligonucleotide tiling arrays used consisted of 381,174 oligonucleotide probes spaced 20 bp apart (30-bp overlap between two probes) across the G. sulfurreducens genome (NimbleGen). Experiments were conducted as three bioliogical replicates (different cultures).
Project description:Investigation of comprehensive information about the transcripts (boundary, level, etc.) across the entire G. sulfurreducens genome in mulitple growth conditions, including in biofilm and on electrode. A five array study using total RNA recovered from two separate culture conditions of G. sulfurreducens. G. sulfurreducens were harvested one week after growth on electrode or to form biofilm. The high-density oligonucleotide tiling arrays used consisted of 381,174 oligonucleotide probes spaced 20 bp apart (30-bp overlap between two probes) across the G. sulfurreducens genome (NimbleGen). Experiments were conducted as two (electrode) or three (biofilm) biological replicates (different cultures).
Project description:We applied a ChIP-chip approach to elucidate the binding profiles of sigma factors (RpH, RpoN and RpoS) experimentally under different growth conditions. This technique localizes DNA fragments within DNA-protein complexes enriched by chromatin immunoprecipitation using high-density oligonucleotide tilling arrays. A 10 ChIP-chip study using immunoprecipitated DNA (IP-DNA) from three culture condtions against three alternative sigma factors . The high-density oligonucleotide tiling arrays used were consisted of 381,174 oligonucleotide probes spaced 20 bp apart (30-bp overlap between two probes) across the G.sulfurreducens genome (NimbleGen). Experiments were conducted as three bioliogical replicates (different cultures).
Project description:The conductive pili of Geobacter sulfurreducens are essential for optimal extracellular electron transfer to Fe(III) and long-range electron transport through current-producing biofilms. The KN400 strain of G. sulfurreducens reduces poorly crystalline Fe(III) oxide more rapidly than the more extensively studied DL-1 strain. Deletion of the gene for PilA, the structural pilin protein, in strain KN400 inhibited Fe(III) oxide reduction. However, slow rates of Fe(III) reduction were detected after extended (> 30 days) incubation in the presence of Fe(III) oxide. After seven consecutive transfers the PilA-deficient strain adapted to reduce Fe(III) oxide as fast as the wild type. Microarray, proteomic, and gene deletion studies indicated that this adaptation was associated with greater production of the c-type cytochrome PgcA, which was released into the culture medium. It is proposed that the extracellular cytochrome acts as an electron shuttle, promoting electron transfer from the outer cell surface to Fe(III) oxides. The adapted PilA-deficient strain competed well with the wild-type strain when both were grown together on Fe(III) oxide. However, when 50% of the culture medium was replaced with fresh medium every three days, the wild-type strain out-competed the adapted strain. A possible explanation for this is that the necessity to produce additional PgcA, to replace the PgcA continually removed, put the adapted strain at a competitive disadvantage, similar to the apparent selection against electron-shuttling producing Fe(III) reducers in most soils and sediments. Despite increased extracellular cytochrome production, the adapted PilA-deficient strain produced low levels of current; consistent with the concept that long-range electron transport through G. sulfurreducens biofilms cannot be achieved without PilA-pili. An eight-chip study using total RNA recovered from four separate cultures of Geobacter sulfurreducens JS-1 (experimental condition) or Geobacter sulfurreducens KN400 (control condition) grown with acetate (10mM)-Fe(III) oxide (100 mmol l-1) exponential growth. Each chip measures the expression level of 3,328 genes from Geobacter sulfurreducens KN400 with nine 45-60-mer probe pairs (PM/MM) per gene, with three-fold technical redundancy.
Project description:This SuperSeries is composed of the following subset Series: GSE21312: Gene expression in a Geobacter sulfurreducens strain adapted for faster Fe(III) oxide reduction grown with ferric citrate as an electron acceptor GSE21313: Gene expression in a Geobacter sulfurreducens strain adapted for faster Fe(III) oxide reduction grown with fumarate as an electron acceptor Refer to individual Series
Project description:Investigation of whole genome changes in six serotypes of Actinobacillus pleuropneumoniae in control cultures compared to bacteria grown in media containg the iron chelator 2,2'-dipyridyl. A 48 chip study using total RNA recovered from four different control cultures and four different iron depleted cultures of Actinobacillus pleuropneumoniea serotype 1 (4074), serotype 2 (4226), serotype 3 (1421), serotype 5b(L209, serotype 6 (7712640) and serotype 7 (WF87).
Project description:This SuperSeries is composed of the following subset Series: GSE17834: Transcriptome analysis of Geobacter sulfurreducens grown with different nitrogen sources GSE17837: ChIP-chip of Geobacter sulfurreducens PCA with antibody against RpoN under various conditions. Refer to individual Series