Degradation of lipopolysaccharide of Escherichia coli by a hot phenol extraction

Abstract

The extraction of lipopolysaccharides (LPS) from Escherichia coli 6234 was studied. It was found that approximately one-half of LPS was extracted with cold phenol-water without stirring (4-LPS). The remaining LPS was extracted with hot phenol-water with stirring (470-LPS). When the cells were extracted directly with hot phenol-water, all LPS was extracted in the aqueous layer (70-LPS). The three preparations were partially purified and their chemical compositions were examined. Marked differences in the chemical compositions were observed between the 4-LPS and 470- or 70-LPS. The 4-LPS was rich in fatty acids and hexosamine in lipid A moiety. The 470- and 70-LPSs showed similar chemical compositions. When the 4-LPS was treated with hot phenol-water, a partial degradation of the lipid A moiety was observed. These results were discussed with respect to the native state of LPS in the outer membrane of the envelope. © 1975, The Japanese Society of Fisheries Science. All rights reserved.