MUTUAL INFLUENCE OF PLASMID PROFILE AND GROWTH TEMPERATURE ON THE LIPID COMPOSITION OF YERSINIA PSEUDOTUBERCULOSIS BACTERIA

Abstract The effect of a 82 MDa plasmid or its 25 MDa DNA fragment and growth temperature on the qualitative and the quantitative fatty acid and phospholipid composition of Yersinia pseudotuberculosis cells has been examined. In the cold, plasmid-containing and plasmid-free strains failed to differ appreciably in the contents of phospholipid and fatty acid. The exceptions were an elevated proportion of diphosphatidylglycerine and a decreased fatty acid unsaturation index in the plasmidless cells and those harbouring an incomplete 57 MDa plasmid in comparison with the strain containing the 82 MDa plasmid. At 37°C, the lack of the 82 MDa plasmid or its 25 MDa fragment gave rise to a phospholipid of unknown structure, led to a sharp decrease in phospholipid content, in PE amount in particular, with a concurrent increase in the quantities of CL and LPE, and with a reduction in index of fatty acid unsaturation. The 82 MDa plasmid seems to be associated with a cancelling a temperature-dependent regulation of lipid synthesis and as a result, both the ‘cold’ and the ‘warm’ variants of the plasmid-containing strain possessed basically the close related lipid contents. Changes in composition of the polar head groups of the membrane phospholipids and in the extent of fatty acid unsaturation were suggested to be connected with an antibiotic hypersensitivity revealed earlier in plasmid-free Y. pseudotuberculosis .