Phospholipids of Clostridium butyricum. V. Effects of growth temperature on fatty acid, alk-1-enyl ether group, and phospholipid composition.

Many anaerobic bacteria have a high proportion of 1-alk-1'-enyl ethers (plasmalogens) among their phospholipids. We have examined the effects of growth temperature on the phospholipid, fatty acid, and alk-1-enyl group compositions of Clostridium butyricum. When the growth temperature was decreased from 37 degrees C to 25 degrees C, the proportion of glycerol phosphoglycerides (the sum of phosphatidylglycerol and the corresponding plasmalogen) increased at the expense of the ethanolamine and N-methylethanolamine phosphoglycerides. Analysis of the proportion of these lipids present in the diacyl and 1-alk-1'-enyl-2-acyl forms has shown a substantial increase in the plasmalogen form of the glycerol phosphoglycerides and a decrease in the plasmalogen forms of the ethanolamine and N-methylethanolamine phosphoglycerides. An analysis of the fatty acids and alk-1-enyl groups isolated from the total phospholipids of cells grown at 25 degrees C, 30 degrees C, and 37 degrees C has shown a general increase in the proportions of unsaturated and cyclopropane hydrocarbon chains at lower growth temperatures. When the temperature was lowered from 37 degrees C to 25 degrees C, the fatty acids had progressively more unsaturated and cyclopropane chains and fewer saturated chains. The alk-1-enyl groups, in particular those from the ethanolamine and N-methylethanolamine plasmalogens, were more saturated at 30 degrees C than at 37 degrees C. When the growth temperature was lowered to 25 degrees C, there was little further change in the degree of unsaturation of the alk-1-enyl groups.