Studies on the lipid and fatty acid composition of Micrococcus radiodurans

Graduation date: 1965Comparatively little work has been done on bacterial lipids.\ud There are profound differences between bacterial lipids in general\ud and lipids of the higher forms of life in such respects as the absence\ud of sterols, phospholipids low in nitrogen but high in inositol\ud and carbohydrate, the presence of large proportions of free fatty\ud acids and the presence of certain fatty acids unique to microorganisms.\ud The purpose of this investigation was to characterize the fatty\ud acids of Micrococcus radiodurans, a gram positive, red-pigmented\ud aerobe, which was isolated from meat, in this laboratory. Lipids\ud were extracted from lyophilized cell extracts of this organism. Free\ud fatty acids were separated using column chromatography methods. The\ud pattern of the various lipid classes was observed on thin-layer\ud chromatograms. Methyl esters of fatty acids were characterized\ud using reversed-phase partition thin-layer chromatography and gas-liquid chromatography techniques.\ud The results of these investigations showed that the organism\ud possesses a spectrum of fatty acids ranging from 12-C to 22-C chain\ud length. The free fatty acid fraction contains a greater percentage\ud of unsaturated fatty acids than saturated fatty acids. Some\ud of these fatty acids have been reported for the first time in a microorganism.\ud The investigation revealed the presence of several long\ud chain poly-unsaturated fatty acids; this could be a major factor responsible\ud for the high resistance of this organism to gamma radiation