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:In this study we further investigate the previously observed syntrophic interaction between Geobacter sulfurreducens and Pseudomonas aeruginosa. In early coculture establishment, two genetic variants of G. sulfurreducens emerged that were strongly selected for throughout coculture evolution. Single nucleotide polymorphism (SNP) variants occurred in fabI and tetR genes of G. sulfurreducens. The tetR variants displayed upregulation of adenylate cyclase transporter, CyaE and of RND efflux pump proteins as determined through SWATH-MS proteomics.
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
Project description:Geobacter sulfurreducens was originally considered a strict anaerobe. However, this bacterium was later shown to not only tolerate but also to use oxygen as terminal electron acceptor. Research performed has so far only revealed the general ability of G. sulfurreducens to reduce oxygen, but the oxygen consumption rate has not been quantified, nor has evidence been provided as to how the bacterium achieves oxygen consumption. The microaerobic growth of G. sulfurreducens under more controlled operating conditions was investigated here and a transcriptome analysis was performed to elucidate possible metabolic mechanisms important for oxygen consumption in G. sulfurreducens. The experiments revealed that growth with oxygen is possible to the same extent as with fumarate when a maximum oxygen load per cell of 95 mgO2gcdw-1h-1 is applied. When oxygen concentrations are too high, growth is completely inhibited and there is no partial consumption. Transcriptome analysis suggests a menaquinol oxidase to be the enzyme responsible for oxygen reduction. Transcriptome analysis has further revealed three different survival strategies, depending on the oxygen concentration present. When prompted with small amounts of oxygen, G. sulfurreducens will try to escape the microaerobic area; if concentrations are higher cells will focus on rapid and complete reduction; and ultimately cells will form protective layers if a complete reduction becomes impossible. The results presented here have important implications for understanding how G. sulfurreducens survives exposure to oxygen.
