Relative gene expression in acid-adapted Escherichia coli O157:H7 during lactoperoxidase and lactic acid challenge in Tryptone Soy Broth
| dc.contributor.author | Parry-Hanson, Angela Araba Bondzewaa | |
| dc.contributor.author | Jooste, Piet J. | |
| dc.contributor.author | Buys, E.M. (Elna Maria) | |
| dc.contributor.email | elna.buys@up.ac.za | en |
| dc.date.accessioned | 2010-02-01T07:31:24Z | |
| dc.date.available | 2010-02-01T07:31:24Z | |
| dc.date.issued | 2010 | |
| dc.description.abstract | Cross-protection of acid-adapted Escherichia coli O157:H7 against inimical stresses is mediated by the glucose-repressed sigma factor RpoS. However, many food systems in which E. coli O157:H7 occurs are complex and contain glucose. This study was aimed at investigating the contribution of acid and lactoperoxidase(LP)-inducible genes to cross- protection of E. coli O157:H7 against LP system and lactic acid(LA)in Tryptone Soy Broth(TSB). Acid-adapted and non-adapted E. coli O157:H7 were challenged to activated LP and LA at pH4.0 and 5.0 in TSBf or 6 h at 25 1C followed by expression of acid and LP- inducible genes. Acid-adapted E. coli showed cross-protection against activated LP and LA. All the acid-inducible genes tested were repressed at pH4.0 with or without activated LP system. At pH7.4, gadA, ompC and ompF were induced in acid-adapted cells. Induction of corA occurred in non-adapted cells but was repressed in acid-adapted cells. Although acid-inducible genes were repressed at pH4.0, high resistance of acid-adapted cells indicates that expression of acid-inducible genes occurred during acid adaptation and not the actual challenge. Repression of rpoS indicates that RpoS-independent systems contribute to cross-protection in acid-adapted E. coli O157:H7. | en |
| dc.identifier.citation | Parry-Hanson AA, et al. Relative gene expression in acid-adapted Escherichia coli O157:H7 during lactoperoxidase and lactic acid challenge in Tryptone Soy Broth. Microbiol Res 2006;(2009),doi:10.1016/j.micres.2009.11.003 | en |
| dc.identifier.issn | 0944-5013 | |
| dc.identifier.other | 10.1016/j.micres.2009.11.003 | |
| dc.identifier.uri | http://hdl.handle.net/2263/12808 | |
| dc.language.iso | en | en |
| dc.publisher | Elsevier | en |
| dc.rights | Elsevier | en |
| dc.subject | Cross-protection | en |
| dc.subject | Lactoperoxidase | en |
| dc.subject | Acid-adaptation | en |
| dc.subject | Real-time PCR | en |
| dc.subject.lcsh | Escherichia coli O157:H7 | en |
| dc.subject.lcsh | Gene expression | en |
| dc.subject.lcsh | Lactic acid | en |
| dc.title | Relative gene expression in acid-adapted Escherichia coli O157:H7 during lactoperoxidase and lactic acid challenge in Tryptone Soy Broth | en |
| dc.type | Postprint Article | en |