Thermal regulation of membrane lipid fluidity by a two‐component system in Bacillus subtilis

• Published in: Biochemistry and molecular biology education 2011-09, Vol.39 (5), p.362-366
• Main Authors: Bredeston, L.M., Marciano, D., Albanesi, D., De Mendoza, D., Delfino, J. M.
• Format: Article
• Language: English
• Subjects: Bacillus subtilis - genetics; Bacillus subtilis - growth & development; Bacillus subtilis - metabolism; beta-Galactosidase - metabolism; Biochemistry; Cell Membrane - metabolism; Cold shock; College Science; Culture Media - chemistry; Enzyme Repression; Fatty Acid Desaturases - genetics; Fatty Acid Desaturases - metabolism; Fatty Acids, Unsaturated - metabolism; Gene Expression Regulation, Bacterial; Genes, Bacterial; Genetics; Laboratory Experiments; Membrane Fluidity; Promoter Regions, Genetic; Science Instruction; Science Laboratories; Scientific Principles; signal transduction; Temperature; Transcription, Genetic; transcriptional regulation
• ISSN: 1470-8175; 1539-3429
• DOI: 10.1002/bmb.20510

This article describes a simple and robust laboratory exercise on the regulation of membrane unsaturated fatty acid composition in bacteria by a decrease in growth temperature. We take advantage of the well characterized Des pathway of Bacillus subtilis, composed of a Δ5‐desaturase (encoded by the des gene) and the canonical two‐component system DesK‐DesR, to study the transcriptional regulation of des during cold shock. Students analyze the expression of a reporter transcriptional fusion between the des promoter and the bacterial lacZ gene in a wild‐type B. subtilis strain and in des or desK‐desR mutants grown under different culture conditions. Measurements of β‐galactosidase activity allow them to investigate how the Des pathway works and to assess the role of each component of this regulatory system. Biochemistry and Molecular Biology Education, 2011