INTRA-STRAIN VARIATION IN EXPRESSION OF LIPOPOLYSACCHARIDE BY HELICOBACTER-PYLORI

Intra-strain variation in the expression of lipopolysaccharide (LPS) b y two clinical isolates of Helicobacter pylori was examined. Lipopolys accharide was prepared from successive cultures of individual colonies from each strain, separated by SDS-PAGE, and detected by silver stain ing and by immunoblotting. The genetic 'relatedness' of the colonies w as investigated using PCR-RFLP analysis of-the urease and vacuolating cytotoxin genes. Although individual colonies of each of the two strai ns examined appeared to have the same genetic origins, variation in th e expression of their long-chain LPS was observed. The same LPS profil es were maintained by individual colonies over four subcultures on sol id media containing 10% (v/v) defibrinated horse blood.