Project description:Comparisson of expression profiling of a etrA deletion mutant strain (experimental sample) with that of the wild type Shewanella oneidensis MR-1 strain to assess global direct/indirect genetic regulation EtrA in Shewanella oneidensis MR-1 shares 73.6% and 50.8% amino acid sequence identity with the oxygen-sensing regulator Fnr in E. coli and Anr in Pseudomonas aeruginosa, respectively; however, its regulatory role of anaerobic metabolism in Shewanella spp. is complex and not well understood. Whole-genome expression profiling using a etrA gene deletion mutant as the experimental sample and the wild type strain as the reference, determine that EtrA fine-tunes the expression of genes involved in various anaerobic metabolic pathways, including nitrate, fumarate and dimethyl sulfoxide reduction. Moreover, genes involved in prophage activation and and genes implicated in aerobic metabolism were also differentially expressed. In contrast to previous studies that attributed a minor regulatory role to EtrA in Shewanella spp., this study demonstrates that EtrA acts as a global transcriptional regulator and cofers physiological advantages to the strain under certain growth conditions.
Project description:To identify the transcriptional targets of the DNA-binding response regulator HnoC (SO_2540), mRNA transcript levels in Shewanella oneidensis were measured using whole genome microarray analysis. Transcript levels were compared between WT Shewanella oneidensis and a hnoC deletion strain.
Project description:Purpose : Identification of the regulons directly and indirectly affected by the main regulators of flagellation in Shewanella putrefaciens CN-32 Methods : mRNA profiles were generated for Shewanella putrefaciens CN-32 samples by deep sequencing. The removal of ribosomal RNA was performed using the Ribo-Zero Bacteria Kit (Illumina) and cDNA libraries were generated with the ScriptSeq v2 Kit (Illumina) . The samples were sequenced in single end mode on an Illumina HiSeq 2500 device and mRNA reads were trimmed using the tool ‘cutadapt’ (version 3.5) with default settings and mapped to the NC_009438.1 (Shewanella putrefaciens CN-32) reference genome from NCBI using ‘bowtie2’ (version 2.3.5.1) with default settings for single-end sequencing.
Project description:Shewanella spp. possess a broad respiratory versatility, which contributes to the occupation of hypoxic/anoxic environmental or host-associated niches. Here we observed a strain-specific induction of biofilm formation in response to supplementation with the anaerobic electron acceptors dimethyl sulfoxide (DMSO) and nitrate in a panel of Shewanella algae isolates. The respiration-driven biofilm response is not observed in DMSO and nitrate reductase deletion mutants of the type strain S. algae CECT 5071, and can be restored upon complementation with the corresponding reductase operon(s) but not by an operon containing a catalytically inactive nitrate reductase. The distinct transcriptional changes, proportional to the effect of these compounds on biofilm formation, include cyclic di-GMP (c-di-GMP) turnover genes. In support, ectopic expression of the c-di-GMP phosphodiesterase YhjH of Salmonella Typhimurium but not its catalytically inactive variant decreased biofilm formation. The respiration-dependent biofilm response of S. algae may permit differential colonization of environmental or host niches.