| Popis: |
A sequential extraction procedure was used to provide 3 endotoxin fractions from Pasteurella haemolytica with distinct biological and solubility properties. After acetone dessication, extraction with phenol, chloroform, and petroleum ether (2:5:8) provided a fraction designated rough lipopolysaccharide (LPS). Subsequent extraction of the cells with 45% phenol at 68 C yielded a fraction designated smooth LPS, which was further divided into smooth precipitate and smooth supernatant, based on sedimentation at 105,000 x g for 4 hours. Yields of the 3 fractions were 1.5%, 3%, and 5.5% of the dry weight of the cells. The polysaccharide moieties of the rough LPS amd smooth precipitate fractions were obtained by partial acid hydrolysis followed by chloroform extraction. Biological activities of all 5 fractions were compared with activities of standard LPS fractions from Serratia marcescens and Salmonella typhimurium. Results of chicken embryo lethality, the local Shwartzman's phenomenon, nonspecific resistance enhancement ot challenge exposure by S typhimurium pyrogenicity, and the Limulus amebocyte lysate assay were reported. |
