ID 111020
Author
Goto, Tsukie Tokushima University|Shikoku University
Tsuji, Makiko Kobe Women's Junior College
Keywords
Escherichia coli O157:H7
Shiga toxin
poly-γ-glutamate
Content Type
Journal Article
Description
We screened foods containing indigestible ingredients in the ability to adsorb Shiga toxin (Stx). When 5 mg of foods and dietary fibers such as dry vegetables and inulin were mixed and incubated with 0.5 mL of Stx solution (100 ng/mL) containing 0.5% bovine serum albumin, both Stx1 and Stx2 seemed to be adsorbed by only a fermented food, natto (a traditional Japanese food prepared from steamed soybeans by the biological action of Bacillus subtilis). We purified the Stx-adsorbing substance from natto by extraction with H 2 O, acid treatment, Proteinase K treatment, and an ion exchange chromatography. The purified substance showed an average molecular mass of about 600 kDa. We identified it as poly-γ -glutamate (PGA) by amino acid analysis of its hydrolysate and peptide analysis after its treatment with Proteinase K. Purified PGA (MW: molecular weight = about 600 kDa) was considered to adsorb both Stx1 and Stx2 when we separated adsorbed and unadsorbed Stxs (MW = about 72 kDa) by an ultrafiltration method with a centrifugal filter unit (MWCO: molecular weight cut-off = 100 K). However, PGA with the ability to adsorb Stx was an insoluble form precipitated in the filter unit during centrifugation. PGA precipitated beyond the saturated density was also confirmed to well adsorb both Stx1 and Stx2 by an equilibrated dialysis method. To the best of our knowledge, this is the 1st report on food-adsorbing Stx.
Journal Title
Journal of Food Science
ISSN
17503841
00221147
NCID
AA12164893
AA00698289
Publisher
Wiley
Volume
81
Issue
12
Start Page
M2977
End Page
M2981
Published Date
2016-10-28
Rights
©2016 Institute of Food Technologists®
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Author
departments
Bioscience and Bioindustry