Chemical characterization of the lipopolysaccharides from enteropathogenicEscherichia coli 0142 and 0158

Lipopolysaccharides (LPS) from two enteropathogenic strains of E. coli O142 and O158 were isolated by hot phenol-water extraction procedure. Polyacryl amide gel electrophoretic pattern of the LPS showed the typical ladder like pattern of smooth type of LPS. The LPS of E coli O158 was found to contain L-rhamnose, D-glucose and N-acetyl-D-galactosamine as major constituents t ogether with D-galactose, N-acetyl-D-glucosamine, L-glycero-D-manno-heptose and 2-keto-3-deoxy-D-manno-octulosonic acid (KDO) whereas LPS from E: coli O142 contained L-rhamnose, N-acetyl-D-glucosamine and N-acetyl-D-galactosa mine as major constituents together with D-glucose, D-galactose, N-acetyl-D -glucosamine, L-glycero-D-manno-heptose and 2-keto-3-deoxy-D-manno-octuloso nic acid (KDO). LPS was degraded by mild acid hydrolysis to yield a degrade d polysaccharide fraction and an insoluble lipid-A fraction. The main fatty acids of the lipid-A fraction of the LPS were C12:O, C14:O, and 3-OH C14:O for O158 strain whereas E, coli O142 lipid-A consisted of C12:O, C14:O, 3- OH C14:O, and C16:O. The degraded polysaccharide fraction on gel permeation chromatography gave a high, molecular weight O-chain fraction and a core o ligosaccharide and a fraction containing degraded sugars. The chemical comp osition of LPS and its fragmented products are reported in this communicati on.