| RRC ID |
35526
|
| 著者 |
Carter MQ, Louie JW, Fagerquist CK, Sultan O, Miller WG, Mandrell RE.
|
| タイトル |
Evolutionary silence of the acid chaperone protein HdeB in enterohemorrhagic Escherichia coli O157:H7.
|
| ジャーナル |
Appl Environ Microbiol
|
| Abstract |
The periplasmic chaperones HdeA and HdeB are known to be important for cell survival at low pH (pH < 3) in Escherichia coli and Shigella spp. Here we investigated the roles of HdeA and HdeB in the survival of various enterohemorrhagic E. coli (EHEC) following exposure to pH 2.0. Similar to K-12 strains, the acid protections conferred by HdeA and HdeB in EHEC O145 were significant: loss of HdeA and HdeB led to over 100- to 1,000-fold reductions in acid survival, depending on the growth condition of prechallenge cells. However, this protection was much less in E. coli O157:H7 strains. Deletion of hdeB did not affect the acid survival of cells, and deletion of hdeA led to less than a 5-fold decrease in survival. Sequence analysis of the hdeAB operon revealed a point mutation at the putative start codon of the hdeB gene in all 26 E. coli O157:H7 strains analyzed, which shifted the ATG start codon to ATA. This mutation correlated with the lack of HdeB in E. coli O157:H7; however, the plasmid-borne O157-hdeB was able to restore partially the acid resistance in an E. coli O145ΔhdeAB mutant, suggesting the potential function of O157-HdeB as an acid chaperone. We conclude that E. coli O157:H7 strains have evolved acid survival strategies independent of the HdeA/B chaperones and are more acid resistant than nonpathogenic K-12 for cells grown under nonfavorable culturing conditions such as in Luria-Bertani no-salt broth at 28°C. These results suggest a divergent evolution of acid resistance mechanisms within E. coli.
|
| 巻・号 |
78(4)
|
| ページ |
1004-14
|
| 公開日 |
2012-2-1
|
| DOI |
10.1128/AEM.07033-11
|
| PII |
AEM.07033-11
|
| PMID |
22179243
|
| PMC |
PMC3273018
|
| MeSH |
Acids / toxicity*
Codon, Initiator
DNA, Bacterial / chemistry
DNA, Bacterial / genetics
Escherichia coli O157 / drug effects*
Escherichia coli O157 / genetics
Escherichia coli O157 / physiology
Escherichia coli Proteins / genetics*
Escherichia coli Proteins / metabolism*
Evolution, Molecular*
Gene Deletion
Genetic Complementation Test
Hydrogen-Ion Concentration
Microbial Viability / drug effects*
Molecular Sequence Data
Mutation, Missense
Point Mutation
Sequence Analysis, DNA
Stress, Physiological
|
| IF |
4.016
|
| 引用数 |
22
|
|
WOS 分野
|
BIOTECHNOLOGY & APPLIED MICROBIOLOGY
MICROBIOLOGY
|
| リソース情報 |
| 原核生物(大腸菌) |
ME9062(BW25113)
JW3478-KC
JW5669-KC |
