title: Thermal regulation of membrane lipid fluidity by a two-component system in Bacillus subtilis.
abstract: 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.
authors.affiliation: Departamento de Química Biológica and IQUIFIB (UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina. bredes@qb.ffyb.uba.ar.
authors.forename: L M
authors.initials: LM
authors.lastname: Bredeston
authors.forename: D
authors.initials: D
authors.lastname: Marciano
authors.forename: D
authors.initials: D
authors.lastname: Albanesi
authors.forename: D
authors.initials: D
authors.lastname: De Mendoza
authors.forename: J M
authors.initials: JM
authors.lastname: Delfino
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D000090943:Delta-5 Fatty Acid Desaturase; D004794:Enzyme Repression; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008560:Membrane Fluidity; D011401:Promoter Regions, Genetic; D013696:Temperature; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D003470:Culture Media; D000090943:Delta-5 Fatty Acid Desaturase; D005231:Fatty Acids, Unsaturated; D044943:Fatty Acid Desaturases; D001616:beta-Galactosidase