Full text loading...
Abstract
SUMMARY: Mycoplasma laidlawii and M. gallisepticum were found to incorporate [14C]acetate from the growth medium mainly into their polar lipids, whereas M. hominis and M. orale incorporated the acetate mainly into their neutral lipids. M. mycoides var. mycoides, Mycoplasma sp. strain 14 and M. fermen-tans did not incorporate acetate, although they were found to possess acetokinase activity. Most of the radioactivity of incorporated acetate was found in the fatty acid fraction of M. laidlawii lipids. Palmitic and stearic acids almost completely inhibited acetate incorporation by this organism, whereas oleic acid did not, indicating that the major part of the acetate incorporated by M. laidlawii was used for the synthesis of saturated fatty acids. Washed M. laidlawii required glucose, coenzyme A (CoA) and Mg2+ for acetate uptake. The uptake process was temperature-dependent and pH-dependent and was inhibited by several metabolic inhibitors, in particular iodoacetate. Pyruvate considerably enhanced acetate incorporation into M. laidlawii lipids without raising the low degree of radioactivity in the cell fraction soluble in cold trichloroacetic acid. Pyruvate did not replace glucose as an energy source for acetate uptake. Propionate and butyrate markedly decreased the acetate uptake, probably by inhibition of the acetokinase activity of the organisms.
- Accepted:
- Published Online: