Search

The total lipids increased with decrease in total phospholipids in Mycobacterium tuberculosis H37Rv grown at 30 degrees as compared to 37 degrees. Oleic and elaidic acid supplemented to the growth medium resulted in a higher total lipid and phospholipid content, but the content was lower in cells grown in the presence of palmitoleic acid. Cellular content of mannophosphoinositides decreased, whereas that of phosphatidylethanolamine and cardiolipin increased at the lower temperature. A decrease in mannophosphoinositides and an increase in cardiolipin were noted with all fatty acid supplements; however, phosphatidylethanolamine behaved differently. The unsaturated to saturated fatty acids ratio increased at low temperature with oleic and elaidic acid supplements, but it decreased with palmitoleic acid. Cells from media supplemented with palmitoleic acid were found to be most virulent to guinea-pigs. Possible correlation of altered lipid composition and virulence of M. tuberculosis H37Rv has been discussed.

Nocardia polychromogenes (saprophytic) and Nocardia asteroides (pathogenic) showed characteristic patterns in changes of cellular lipids during growth. Total lipids and total phospholipids decreased with the age of the culture in the saprophytic strain, whereas in the pathogenic strain total lipids increased throughout the culture period and the total phospholipids decreased in the late stationary phase. The decrease in total phospholipids in saprophytic strain was reflected in the individual phosphatides. In the pathogenic strain, the phosphatidylinositomannoside content doubled in early stationary phase. Differences were observed in fatty acid composition of phosphatides at various stages of growth, but the ratio of saturated to unsaturated fatty acids remained unaltered.