Bacterial adaptive response to osmotic stress. Proteome alterations

Project Report from the year 2014 in the subject Biology - Micro- and Molecular Biology, grade: 2,0, LMU Munich, language: English, abstract: Escherichia coli inhabits the mammalian gastrointestinal tract anaerobically at high osmolarity as well as the soil aerobically where it is faced with rapid variations in osmolarities. Fermentation technology using E. coli followed by IEF-2D-PAGE was implied to visualize global proteome alterations under normal aerobic conditions and conditions of high osmolarity (0.4M NaCl). The protein profile revealed an up-regulation in the expression of ProX, HchA, OsmY and OtsB in osmotic stress induced cells, as well a down- regulation of two proteins named FliC and MetF in cells under hyper-osmotic conditions. Another protein, GlnA seemed to be expressed at equal rates under both conditions.The aim of this work was a comparative qualitative analysis of the proteome of E. coli grown under normal and high osmolarity conditions by employing fermentation technology and 2D- electrophoresis for protein analysis. Following the hypothesis that it is necessary for bacteria to up-regulate de expression of certain proteins under osmotic stress conditions, the underlying experiments were aimed at identifying global alterations in protein expression under two different environmental conditions.