LIPID COMPOSITION AND SYNTHESIS IN THE PLEUROPNEUMONIA-LIKE ORGANISM MYCOPLASMA GALLISEPTICUM

Abstract

A simple method of extracting lipids from cells of M. gallisepticum by use of siiicic-acid columns is described. Proteolipids (peptides) extracted with chloroform-methanol (2:1) by other methods were not extracted with the lipid by this method, nor were proteins and nucleic-acids. Fractionation of lipids of M. gallisepticum demonstrated the presence of saturated hydrocarbons, free fatty-acids, cholesterol, cholesterol-esters, di- and triglycerides, phosphatidic-acids, cephalins, inositides, phosphatidyl-choline and sphingomyelin. The fatty-acid composition of the various fractions was also determined. The positive identification of cholesterol and cholesterol esters in this organism by chromatography, melting point and infrared spectroscopy confirms reports by others that cholesterol is present in the pleuropneumonia group of microorganisms. The incorporation of P32 orthophosphate into four phospholipid fractions, of oleic-acid-1-C14 into neutral and phospholipids and cholesterol-4-C14 into cholesterol-esters clearly demonstrated the ability of M. gallisepticum to synthesize these lipids from simpler compounds. Between 70 and 80% of the lipid of this organism was found in the membrane.