Bound and spontaneously released toxic products of NAG vibrios cultivated in minimal synthetic media

Abstract

Properties of toxic substances released spontaneously and by ultrasonic disintegration from NAG vibrio cells cultivated in minimal synthetic medium were compared. The released material was separated on the AMICON ultramembranes, dialysed and fractionated on the column of Sephadex G-100. This procedure revealed three fractions released by ultrasonic disintegration. The culture released spontaneously only one fraction separated by the above mentioned procedure. The molecular weight estimated by the elution from calibrated G-100 column of the fractions released by the ultrasound was a follows: first fraction (H1) over 100,000, second fraction (H2) 25,000-30,000 and third one (H3) below 10,000. The molecular weight of the spontaneously released fraction (F1) was over 100,000. The biological activity of the fractions was tested by the rabbit skin test and by the rabbit ligated ileal loop test. The fractions H1, H2 and F1 were positive in both while the fraction H3 was negative. Fraction F1 was inactivated at 56 degrees C while at 100 degrees C its activity was restored. In agar gel diffusion test, the presence of endotoxin in fraction F1 was proved by means of specific antiserum. Results show that the toxic substances of enterotoxin nature are bound also to cell structures. They reveal the biological activity qualitatively and quantitatively different of the spontaneously released substances. Besides the endotoxin also other cell components can contribute to these effects.