title: Temperature- and growth-phase-regulated changes in lipid fatty acid structures of psychrotolerant groundwater Proteobacteria.
abstract: Cellular fatty acid compositions of five psychrotolerant groundwater isolates representing alpha- and beta-Proteobacteria were studied at temperatures ranging from 8 to 25 degrees C. Unsaturation of straight-chain fatty acids was the most common response to decreasing temperature and was detected in four of the isolates. On solid media, decrease of temperature resulted in a decrease of cyclopropane fatty acids in beta-proteobacterial isolates. The formation of cyclopropane fatty acids depended, however, to a greater extent on the growth phase than the temperature and increased drastically as the cells entered stationary phase. The alpha-proteobacterial isolates contained a branched C(19:1) fatty acid. The formation of the branched C(19:1) increased during growth in the same way as the cyclopropane fatty acids in beta-proteobacterial strains, indicating possibly an analogous formation of the branched fatty acid by methylation of the 18:1 fatty acid. Sphingomonas sp. K6 possessed a novel temperature-induced modification of lipid fatty acids. As temperature decreased from 25 to 8 degrees C, the fatty acid composition shifted from predominantly even-carbon fatty acids to odd-carbon fatty acids. The results show completely different fatty acid modifications in two strains of the same genus Sphingomonas.
authors.affiliation: Institute of Environmental Engineering and Biotechnology, Tampere University of Technology, P.O. Box 541, 33101 Tampere, Finland. minna.mannisto@metla.fi
authors.forename: M K
authors.initials: MK
authors.lastname: Männistö
authors.forename: J A
authors.initials: JA
authors.lastname: Puhakka
mesh_terms: D000222:Adaptation, Physiological; D020561:Alphaproteobacteria / Q000737:chemistry / Q000254:growth & development*; D020562:Betaproteobacteria / Q000737:chemistry / Q000254:growth & development*; D003080:Cold Temperature; D003470:Culture Media; D005227:Fatty Acids / Q000032:analysis*; D005618:Fresh Water / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial; D013696:Temperature
chemical_list: D003470:Culture Media; D005227:Fatty Acids