The effect of the cultivation method and the growth phase on the lipopolysaccharide composition of Yersinia pseudotuberculosis

Effects of the cultivation method (suspension cultures in a liquid nutrient broth or colonies on a solid agarized medium) and the growth phase on the lipopolysaccharide (LPS) composition of Yersinia pseudotuberculosis (O : Ib serovar, strain KS 3058) grown in cold (5 degreesC) were studied. The amou nt of the LPS synthesized by cells depended on the bacteria, growth phase f or both media. The LPS acylation degree was constant, whereas the length of the O-specific polysaccharide chain varied with the culture age and for bo th media achieved maximum in the stationary growth phase. The bacteria cult ivation on the nutrient agar stimulated more intensive synthesis of LPS, wh ich were extracted more easily, had longer polysaccharide O-chains, and wer e more toxic than LPS of the bacteria cultivated in the liquid medium. It w as proposed that the cultivation of Yersinia pseudotuberculosis in cold as colonies on the agar surface increases the bacterial virulence.