Studies of enterotoxin of Shigella dysenteriae type 1. I. Effect of aeration on the production of enterotoxin and suitability of laboratory animals for its biological assay

Abstract

Shigella dysenteriae type 1 was used to study the influence of aeration on enterotoxin production and the suitability of laboratory animals for the toxin assay. The enterotoxin produced under aerobic shake culture conditions gave a gut dilatory response of 1.436 but that obtained in aerobic and anaerobic stationary cultures exerted no activity. The toxin fractionated on Sephadex G-150 column was more effective than that obtained by ammonium sulphate precipitation. Only Sephadex column fraction II had a toxic activity. Among the three laboratory animal models tested, the rabbit ileal loop was suitable for the assay of toxin. The skin permeability test was unsatisfactory for enterotoxicity assay.