Project description:We investigated the anode-specific responses of Shewanella oneidensis MR-1, an exoelectroactive ammaproteobacterium, using for the first time iTRAQ and 2D-LC MS/MS driven membrane proteomics to compare protein abundances in S. oneidensis when generating power in MFCs, and growing in a continuous culture.
Project description:We combined high-resolution tiling microarrays and 5'-end RNA sequencing to obtain a genome-wide map of transcription start sites (TSSs) for Shewanella oneidensis MR-1. To test the reliability of these TSSs, we compared our result to those from differential RNA sequencing (dRNA-seq), which discriminates primary and processed ends of transcripts. We found that our identified TSSs tend to have significantly more mapped reads in the TEX(+) sample than the TEX(-) sample. Overall, the dRNA-seq results support the validity of our predictions for TSS.
Project description:High-resolution tiling analysis of the MR-1 transcriptome under diverse growth conditions The conditions include aerobic growth in Luria-Bertani broth (LB), aerobic growth in defined lactate minimal medium, anaerobic growth in defined lactate minimal medium with 20mM dimethyl sulfoxide as the electron acceptor, anaerobic growth in defined lactate minimal medium with 10mM iron (III) citrate as the electron acceptor, 10 minutes post heat shock at 42oC see GSE39468 for tiling data on lactate minimal media
Project description:Purpose: The goals of this study are to find out the differential expression genes in the fadR mutant strain(ΔfadR) compared with wild-type (WT) and to further explore the regulation mechanisms of fadR. Methods: Shewanella oneidensis MR-1 WT and ΔfadR were collected in log phage(OD~0.6). RNA extraction was performed using the RNeasy minikit (Qiagen) and the RNA was quantified by using a NanoVue spectrophotometer (GE Healthcare). RNA seq was performed using Illumina NextSeq 500, 2×150 bp. Results: Our study represents that the expression of 146 genes were decreased and 94 genes were increased inΔfadR compared with WT. Branched-chain keto acid dehydrogenase (BKD) produces corresponding branched-chain acyl coenzyme A which further participating branchend-chain fatty acids synthesis. The expression of bkdA2 was also promoted in △fadR compared with WT. Conclusions: Combined with our expression results, it declared that FadR can suppress bkd operon in some degree,which further increase the synthesis of branched-chain fatty acids in ΔfadR.
Project description:The central metabolic fluxes of Shewanella oneidensis MR-1 were examined under carbon-limited (aerobic) and oxygen-limited (microaerobic) chemostat conditions, using 13C-labeled lactate as the sole carbon source. The carbon labeling patterns of key amino acids in biomass were probed using both gas chromatography-mass spectrometry (GC-MS) and 13C nuclear magnetic resonance (NMR). Based on the genome annotation, a metabolic pathway model was constructed to quantify the central metabolic flux distributions. The model showed that the tricarboxylic acid (TCA) cycle is the major carbon metabolism route under both conditions. The Entner-Doudoroff and pentose phosphate pathways were utilized primarily for biomass synthesis (with a flux below 5% of the lactate uptake rate). The anaplerotic reactions (pyruvate to malate and oxaloacetate to phosphoenolpyruvate) and the glyoxylate shunt were active. Under carbon-limited conditions, a substantial amount (9% of the lactate uptake rate) of carbon entered the highly reversible serine metabolic pathway. Under microaerobic conditions, fluxes through the TCA cycle decreased and acetate production increased compared to what was found for carbon-limited conditions, and the flux from glyoxylate to glycine (serine-glyoxylate aminotransferase) became measurable. Although the flux distributions under aerobic, microaerobic, and shake flask culture conditions were different, the relative flux ratios for some central metabolic reactions did not differ significantly (in particular, between the shake flask and aerobic-chemostat groups). Hence, the central metabolism of S. oneidensis appears to be robust to environmental changes. Our study also demonstrates the merit of coupling GC-MS with 13C NMR for metabolic flux analysis to reduce the use of 13C-labeled substrates and to obtain more-accurate flux values.