CHARACTERIZATION OF LIPOLYTIC-ACTIVITY ASSOCIATED WITH A VIBRIO SPECIES OF BACTERIUM ISOLATED FROM FISH INTESTINES

Cultures of a species of Vibrio isolated from fish intestines and know n to synthesize the polyunsaturated fatty acid eicosapentaenoic acid ( 20:5n-3) were incubated with di-[1-C-14]palmitoyl phosphatidylcholine to determine if lipolytic enzymes are produced by the bacteria. After two days of culture, most radioactivity was recovered in the phospholi pids of the bacterial cells. When supernatants from cultures of the Vi brio were incubated with either di-[1-C-14]palmitoyl phosphatidylcholi ne, 1-palmitoyl-2-[1-C-14]linoleoyl phosphatidylcholine or 1-[1-C-14]p almitoyl lysophosphatidylcholine almost all radioactivity was recovere d in the free fatty acid fraction after 24 h. Only very small levels o f radioactivity from di-[1-C-14]palmitoyl phosphatidylcholine were rec overed in diacylglycerols and phosphatidic acid. Over the same incubat ion period 61% and 5% of the radioactivity originally present in glyce rol tri-[1-C-14]oleate and cholesteroyl [1-C-14]oleate, respectively, was released to free fatty acids. Soybean phosphatidylcholine and cod roe phosphatidylcholine, which differed in polyunsaturated fatty acid profile, were both hydrolyzed by culture supernatant. The results sugg est that the Vibrio species examined produces a phospholipase B capabl e of hydrolyzing both intact phospholipids and lysophospholipids.