Chemical and Biological Properties of Lipopolysaccharide from a Marine Bacterium, <i>Photobacterium phosphoreum</i> PJ‐1

Abstract

Abstract The chemical and biological properties of the lipopolysaccharide (LPS) isolated from a marine bacterium, Photobacterium phosphoreum PJ‐1, were studied. This LPS consists of 40.6% carbohydrate, 27.3% fatty acid, 0.2% 2‐keto‐3‐deoxyoctonate (KDO) and other components. One characteristic of this LPS is its small amount of KDO, the basic component of the usual LPS. Electrophoresis in sodium dodecylsulfate polyacrylamide gel revealed at least two staining bands for carbohydrates. These bands were continuous and broad, and showed rapid electrophoretic mobility which corresponded closely to the fastest moving band of LPS from Salmonella typhimurium . This LPS preparation had adjuvant activity, lethality for ddY mice, and the ability to gel Limulus amebocyte lysate, and the strength of these activities corresponded closely to those of LPS preparations from Escherichia coli 0111:B4 and S. typhimurium . In the test for lethality of the LPS for ddY mice, the lethal action appeared in two phases depending on the dose used for intravenous (i.v.) injection : the early lethal action appeared within 30 min after injection of 250 μg or less, and the late lethal action occurred gradually after 16 hr at doses of 500 μg or more. The total (both phases) LD50 of this LPS (i.v.) for ddY mice was 265 μg per mouse and in only the late phase it was 500 μg. These results show that in spite of structual differences in regard to KDO content, LPS from P. phosphoreum PJ‐1 has some biological properties similar to those of LPS from E. coli 0111:B4 and S. typhimurium but it shows no immunological cross‐reaction with other LPS.