Escherichia coli enterotoxin. Purification and partial characterization.

F Dorner

doi:10.1016/s0021-9258(19)40730-8

Abstract

Enterotoxin, a diarrheagenic protein elaborated by pathogenic Escherichia coli strains has been isolated from the supernatant of fermenter cultures of E. coli strain P263, a porcine enteropathogen. Purification steps involving Bio-Gel agarose A-5m, Sephadex G-75 chromatography, and preparative isotachophoresis were used in the isolation. The resulting product appears to be pure according to immunoelectrophoretic, disc electrophoretic, ultracentrifugal, and immunologic criteria. The entertoxin has an apparent molecular weight of 102,000 as judged by gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis, and its isoelectric point is 6.90. The isolated product is highly active in inducing experimental diarrhea in adult rabbits and piglets. It also elicits, in small dosage, a marked increase in adenylate cyclase activity in broken cell preparations of cat heart tissue. The enterotoxin activity is acid-labile and is destroyed by heating at 65 degrees for 30 min. It is suggested that the heat-stable enterotoxin material is derived from heat-labile enterotoxin by forming a complex with endotoxin or capsular material present in the culture supernatant.

Highlights

Enterotoxin, a diarrheagenic protein elaborated by pathogenic Escherichia coli strains has been isolated from the supernatant of fermenter cultures of E. coli strain P263, a porcine enteropathogen
The V. cholerae enterotoxin has been isolated in a pure state and has been subjected to extensive physical and chemical characterization, whereas the E. coli enterotoxin has resisted efforts aimed at purification and characterization [7, 8]
This paper describes the purification and partial characterization of the heat-labile enterotoxin from a strain of E. coli reported to be associated with diarrhea1 disease in pigs

Summary

Introduction

Enterotoxin, a diarrheagenic protein elaborated by pathogenic Escherichia coli strains has been isolated from the supernatant of fermenter cultures of E. coli strain P263, a porcine enteropathogen. The severe losses of water and electrolytes which occur in E. coli infection appear to be caused by this toxin whose action is mediated by stimulation of adenylate cyclase activity in the epithelial cells of the small intestine with a consequent increase in the intracellular concentration of cyclic adenosine 3’:5’-monophosphate [4, 5]. In this respect the heat-labile E. coli enterotoxin shows some characteristics of Vibrio cholerae enterotoxin [6]. The methods that have been successfully used for the study of the pathophysiological effect of V. cholerae enterotoxin were, applied to elucidate the biological activities of the E. coli enterotoxin itself [9,10,11,12,13,14,15,16,17]

Methods

Results

Conclusion