Fatty Acid Independent Adaptations of Bacterial Membranes to Cold Temperatures

• Applicant: Professor Dr. André Lipski
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: from 2014 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 258101465

One of the most important adaptations of microorganisms to cold temperatures is the control of cell membrane fluidity. Published data and own preliminary analyses indicate that membrane adaptation fluidity for bacteria is not only realized by changes of the fatty acid profile but other mechanisms which are not analyzed in detail so far. In this study we will analyze the participation of other constituent lipid structures of the membrane like quinones, hopanoids and carotenoids on membrane adaption. We will test the hypothesis that regulation of membrane fluidity can be regulated by increase of the concentration of these compounds. Four model organisms were selected for these analyses. These were bacterial isolates from different taxa, which were isolated from cold habitats in previous projects. Preliminary analyses have shown only small adaptations of their fatty acid profiles to low growth temperatures. The selected model strains will be subjected to a quantitative analyses of quinones, hopanoids and carotenoids related to the respective growth temperature. These analyses will be accompanied by measurement of membrane fluidity. Supplementation with external quinone and carotin will reveal the impact of these lipids on membrane fluidity. The accompanying lipid analyses will show the cellular reaction on this deflection. For the four strains a supplemental analysis of cold-regulated gene expression will be performed. The combination of lipid and gene expression analyses will provide reliable information about adaptation mechanisms other than fatty acid profile modification. The analyses will provide first information about the regulation of these adaptive responses by identification of up-regulated genes of the respective synthesis pathways under cold conditions.

• DFG Programme: Research Grants