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

The effect of a 82 MDa plasmid or its 25 MDa DNA fragment and growth t emperature on the qualitative and the quantitative fatty acid and phos pholipid composition of Yersinia pseudotuberculosis cells has been exa mined, 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 cell s and those harbouring an incomplete 57 MDa plasmid in comparison with the strain containing the 82 MDa plasmid, At 37 degrees C, the lack o f the 82 MDa plasmid or its 25 MDa fragment gave rise to a phospholipi d of unknown structure, led to a sharp decrease in phospholipid conten t, in PE amount in particular, with a concurrent increase in the quant ities of CL and LPE, and with a reduction in index of fatty acid unsat uration, 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 stra in possessed basically the close related lipid contents, Changes in co mposition of the polar head groups of the membrane phospholipids and i n the extent of fatty acid unsaturation were suggested to be connected with an antibiotic hypersensitivity revealed earlier in plasmid-free Y. pseudotuberculosis.