Characterization of extracellular substance of Vibrio anguillarum toxic for rainbow trout and mice.

An extracellular toxic substance was separated from the cell-free culture filtrate of Vibrio anguillarum (strain NCMB571). Two fractions (GI and GII + III) obtained by Sephadex G-200 chromatography following DEAE-cellulose chromatography were lethal to rainbow trout and mice. Material separated from the GI fraction by Sepharose 4B affinity chromatography (GI-A fraction) was lethal to these animals. By sodium dodecylsulfate polyacrylamide gel electrophoresis, the GI and GI-A fractions were found to be composed of components with molecular weights of 44K and 34K, and 44K, respectively. The 44K protein band was associated with carbohydrate. Peripheral vascular disorder was observed in fish and mice that died after inoculation with GI or GI-A fraction. The toxic substance was sensitive to potassium periodate but was resistant to trypsin and acetone. Heat inactivation of the toxic substance was almost complete at 100 C for 20 min and complete at 121 C for 20 min. The toxic activity was not associated with hemolytic or proteolytic activity. Homologous antitoxin completely neutralized the toxic activity.