Open AccessCONTROL OF FATTY ACID COMPOSITION IN PHOSPHOLIPIDS OF Escherichia coli : RESPONSE TO FATTY ACID SUPPLEMENTS IN A FATTY ACID AUXOTROPH
Author(s) -
Mohammad Reza Esfahani,
Eugene M. Barnes,
Salih J. Wakil
Publication year - 1969
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.64.3.1057
Subject(s) - fatty acid , biochemistry , unsaturated fatty acid , composition (language) , auxotrophy , phospholipid , chemistry , escherichia coli , lysis , food science , biology , gene , linguistics , philosophy , membrane
The effect of exogenous unsaturated fatty acids on the fatty acid composition of phospholipids of a mutant ofE. coli has been examined. These exogenous acids serve as growth factors for an auxotroph requiring unsaturated fatty acids. When each member of a structurally homologous series ofcis -unsaturated fatty acids serves as a growth factor, the percentage of unsaturated fatty acid present in phospholipids increases with increasing chain length or decreasing number of double bonds in the apolar chain of the supplement. At 37°,trans -octadecenoic acids support growth and are incorporated into phospholipids at levels higher than the correspondingcis -acids. However, a temperature shift to 27° withtrans -acids results in loss of viability and lysis. Utilization ofcis -acids as supplements at decreasing temperatures between 42° and 27° results in increasing amounts of unsaturated fatty acids in phospholipids with decreasing temperature. These observations suggest the operation of a regulatory mechanism which controls the composition of saturated versus unsaturated acids in order to maintain the physical properties of phospholipids within narrow limits.