| Effect of trisodium phosphate adaptation on changes in membrane lipid composition, verotoxin secretion, and acid resistance of Escherichia coli O157:H7 in simulated gastric fluid. | |
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MedLine Citation:
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PMID: 16213051 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Escherichia coli O157:H7 (HEC), E. coli O157:H7 rpoS mutant (HEC-RM), and nonpathogenic E. coli (NPEC) were step-wise adapted to trisodium phosphate (TSP) by incubation in broths of increasing concentration, from 0% to 0.6%, at 37 degrees C for 24 h. After incubation at each concentration, each population was examined for acid resistance (D value) in simulated gastric fluid of pH 1.5, cell envelope membrane lipid composition, and intracellular and extracellular verotoxin concentrations. The ratio of cis-vaccenic acid (18:1omega7c) to palmitic acid (16:0) increased, indicating increased membrane fluidity with increasing TSP concentration up to 0.4%, but decreased at 0.6%. HEC and HEC-RM adapted at 0.4% TSP had the highest verotoxin concentrations of 1805 and 1879 ng/ml, respectively. In addition, with HEC the ratio of extracellular to intracellular verotoxin concentration decreased at higher TSP concentrations. In contrast, the ratio for HEC-RM increased at 0.4% TSP. HEC adapted to 0.4% TSP had the greatest survival in gastric fluid (58 min D value) among all treatments. For HEC, the increase in membrane fluidity was associated with increased acid resistance and extracellular verotoxin concentration for cells adapted to 0.4% TSP. In contrast, the increase in membrane fluidity was associated with decreased acid resistance of TSP adapted HEC-RM although the extracellular verotoxin concentration increased. Therefore, the deletion of the rpoS gene appeared to affect the changes in verotoxin concentration and acid resistance of TSP adapted E. coli O157:H7. |
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Authors:
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Hyun-Gyun Yuk; Douglas L Marshall |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2005-10-05 |
Journal Detail:
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Title: International journal of food microbiology Volume: 106 ISSN: 0168-1605 ISO Abbreviation: Int. J. Food Microbiol. Publication Date: 2006 Jan |
Date Detail:
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Created Date: 2005-12-26 Completed Date: 2006-02-21 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8412849 Medline TA: Int J Food Microbiol Country: Netherlands |
Other Details:
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Languages: eng Pagination: 39-44 Citation Subset: IM |
Affiliation:
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Department of Food Science, Nutrition, and Health Promotion, Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, Box 9805, Mississippi State, MS 39762-9805, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological* Dose-Response Relationship, Drug Escherichia coli / drug effects, genetics, growth & development Escherichia coli O157* / drug effects, genetics, growth & development Food Microbiology Gastric Acid* / physiology Hydrogen-Ion Concentration Membrane Lipids / chemistry* Mutation Phosphates / pharmacology* Shiga Toxins / analysis*, biosynthesis Time Factors |
| Chemical | |
Reg. No./Substance:
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0/Membrane Lipids; 0/Phosphates; 0/Shiga Toxins; 7632-05-5/sodium phosphate |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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