title: Genes of Escherichia coli O157:H7 that are involved in high-pressure resistance.
abstract: Seventeen Escherichia coli O157:H7 strains were treated with ultrahigh pressure at 500 MPa and 23 +/- 2 degrees C for 1 min. This treatment inactivated 0.6 to 3.4 log CFU/ml, depending on the strain. The diversity of these strains was confirmed by pulsed-field gel electrophoresis (PFGE) analysis, and there was no apparent association between PFGE banding patterns and pressure resistance. The pressure-resistant strain E. coli O157:H7 EC-88 (0.6-log decrease) and the pressure-sensitive strain ATCC 35150 (3.4-log decrease) were treated with a sublethal pressure (100 MPa for 15 min at 23 +/- 2 degrees C) and subjected to DNA microarray analysis using an E. coli K-12 antisense gene chip. High pressure affected the transcription of many genes involved in a variety of intracellular mechanisms of EC-88, including the stress response, the thiol-disulfide redox system, Fe-S cluster assembly, and spontaneous mutation. Twenty-four E. coli isogenic pairs with mutations in the genes regulated by the pressure treatment were treated with lethal pressures at 400 MPa and 23 +/- 2 degrees C for 5 min. The barotolerance of the mutants relative to that of the wild-type strains helped to explain the results obtained by DNA microarray analysis. This study is the first report to demonstrate that the expression of Fe-S cluster assembly proteins and the fumarate nitrate reductase regulator decreases the resistance to pressure, while sigma factor (RpoE), lipoprotein (NlpI), thioredoxin (TrxA), thioredoxin reductase (TrxB), a trehalose synthesis protein (OtsA), and a DNA-binding protein (Dps) promote barotolerance.
authors.affiliation: Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Road, Columbus, OH 43210, USA.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Malone
authors.forename: Yoon-Kyung
authors.initials: YK
authors.lastname: Chung
authors.forename: Ahmed E
authors.initials: AE
authors.lastname: Yousef
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016521:Electrophoresis, Gel, Pulsed-Field; D019453:Escherichia coli O157 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005519:Food Preservation / Q000379:methods; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D006801:Humans; D006874:Hydrostatic Pressure; D020411:Oligonucleotide Array Sequence Analysis
chemical_list: D001426:Bacterial Proteins