INFLUENCE OF UNSATURATED FATTY-ACIDS, MEMBRANE FLUIDITY AND OXYGENATION ON THE SURVIVAL OF AN ESCHERICHIA-COLI FATTY-ACID AUXOTROPH FOLLOWING GAMMA-IRRADIATION

Escherichia coli K1060, a fatty acid auxotroph unable to either synthesize or degrade unsaturated fatty acids (uFAs), was used to study the effect of membrane fluidity on survival after exposure to ionizing radiation. Using this strain of E. coli, significant alterations in the fatty acid composition of the membrane have been produced and verified by gas chromatography. Linolenic, oleic, elaidic and palmitelaidic acids were the uFAs used. Survival above the transition temperature (Tt) (liquid crystalgel) was comparable for these fatty-acid-supplemented membranes after exposure to γirradiation, whereas γirradiation below Tt resulted in a significant decrease in survival. An oxygen enhancement effect was observed for each experimental condition employed. © 1979 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.