SEPARATION OF 2 LIPOPOLYSACCHARIDE POPULATIONS WITH DIFFERENT CONTENTS OF O-ANTIGEN FACTOR 122 IN SALMONELLA-ENTERICA SEROVAR TYPHIMURIUM

Lipopolysaccharide (LPS) extraction from smooth-type Salmonella enterica sv. Typhimurium was carried out with the modified phenol/chloroform/petroleum ether method (volume ratio 5:5:8). In this procedure, LPS was precipitated from 90% phenol sequentially with water and acetone to yield LPS-H2O (minute amounts) and LPS-Ac (major amounts), respectively. Chemical analyses of the LPS fractions revealed that in the O antigen of LPS-H2O position C4 of the D-galactose was extensively glucosylated, corresponding to the O-antigen factor 12(2). In LPS-Ac, this glucosylation was negligible. Inspection of the LPS fractions by sodium dodecyl sulphate/polyacrylamide gel electrophoresis and silver staining suggested that the glucosylation in LPS-H2O WaS Present only in LPS species with a chain length higher than six repeating units.