Inhibition of Binding of the AB5-Type Enterotoxins LT-I and Cholera Toxin to Ganglioside GM1 by Galactose-Rich Dietary Components

P.M. Becker, H.C.A. Widjaja-Greefkes, P.G. van Wikselaar

Research output: Contribution to journalArticleAcademicpeer-review

14 Citations (Scopus)

Abstract

Cholera, travelers' diarrhea, or colibacillosis in pigs can possibly be prevented or attenuated by dietary provision of competitive inhibitors that react with the GM1-binding sites of the enterotoxins cholera toxin (CT), human Escherichia coli heat-labile enterotoxin of serogroup I (LTh-I), and porcine LT-I (LTp-I). The interfering efficiency of natural substances with binding of the toxins to the gangliosid receptor GM1 was tested using a specially adapted GM1-coated-microtiter-well enzyme-linked immunosorbent assay. The substances tested for their GM1 displacing capacity were galactose-containing or -related saccharides from bovine milk, skim milk powder, galactan from gum arabic, food stabilizers as well as ground fenugreek seed and soy bean constituents that contain galactomannans, the galactopolysaccharides agar and agarose, and larch wood and other plant materials that contain arabinogalactans. Skim milk powder, compared with the pure milk saccharides tested, interfered to a higher extent with LTh-I (65–66% inhibition at 5mg test substance/mL) and CT binding (63–67% inhibition at 5mg test substance/mL) when supplied before or simultaneously with the toxins in the GM1-enzyme-linked immunosorbent assay. Ground fenugreek seed counteracted GM1 binding of 5ng LTh-I/mL as well as 5ng and 1µg LTp-I/mL (43–65% inhibition at 5mg test substance/mL), and 4ng CT/mL (61–92% inhibition at 5mg test substance/mL) very efficiently when supplied before the toxin–GM1 complex had formed. With 50mg/mL fenugreek seed, inhibition percentages of even 92–99% were reached for LTh-I and CT binding. Efforts to resolve already bound toxin from GM1 with the test substances were less effective than preincubations and concurrent incubations.
Original languageEnglish
Pages (from-to)225-233
JournalFoodborne Pathogens and Disease
Volume7
Issue number3
DOIs
Publication statusPublished - 2010

Keywords

  • heat-labile enterotoxin
  • escherichia-coli
  • receptor antagonists
  • crystal-structure
  • b-pentamer
  • human-milk
  • oligosaccharides
  • plasmids
  • identification
  • strains

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