Affiliation:
1. Department of Respiration, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
Abstract
ABSTRACT
Heat-labile enterotoxin (LT), the major virulence factor of enterotoxigenic
Escherichia coli
(ETEC), can lead to severe diarrhea and promotes ETEC adherence to intestinal epithelial cells. Most previous
in vitro
studies focused on ETEC pathogenesis were conducted under aerobic conditions, which do not reflect the real situation of ETEC infection because the intestine is anoxic. In this study, the expression and secretion of LT under anaerobic or microaerobic conditions were determined; LT was not efficiently secreted into the supernatant under anaerobic or microaerobic conditions unless terminal electron acceptors (trimethylamine
N
-oxide dihydrate [TMAO] or nitrate) were available. Furthermore, we found that the restoration effects of TMAO and nitrate on LT secretion could be inhibited by amytal or Δ
torCAD
and Δ
narG
E. coli
strains, indicating that LT secretion under anaerobic conditions was dependent on the integrity of the respiratory chain. At the same time, electron acceptors increase the ATP level of ETEC, but this increase was not the main reason for LT secretion. Subsequently, the relationship between the integrity of the respiratory chain and the function of the type II secretion system was determined. The GspD protein, the secretin of ETEC, was assembled under anaerobic conditions and was accompanied by LT secretion when TMAO or nitrate was added. Our data also demonstrated that TMAO and nitrate could not induce the GspD assembly and LT secretion in Δ
torCAD
and Δ
narG
strains, respectively. Moreover, GspD assembly under anaerobic conditions was assisted by the pilot protein YghG.
Funder
National Natural Science Foundation of China
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献