期刊
MICROBIOLOGY-SGM
卷 148, 期 -, 页码 1655-1666出版社
SOC GENERAL MICROBIOLOGY
DOI: 10.1099/00221287-148-6-1655
关键词
pathogenesis; intestinal colonization; CTXphi receptor
类别
资金
- NIAID NIH HHS [AI-42347] Funding Source: Medline
The toxin-coregulated pilus (TCP) is a critical determinant of the pathogenicity of Vibrio cholerae. This bundle-forming pilus is an essential intestinal colonization factor and also serves as a receptor for CTXphi, the filamentous phage that encodes cholera toxin (CT). TCP is a polymer of repeating subunits of the major pilin protein TcpA and tcpA is found within the Vibrio pathogenicity island (VPI). In this study genetic variation at the tcpA locus in toxigenic isolates of V. cholerae was investigated and three novel TcpA sequences from V. cholerae strains V46, V52 and V54, belonging to serogroups 0141, 037 and 08, respectively, were identified. These novel tcpA alleles grouped into three distinct clonal lineages. The polymorphisms in TcpA were predominantly located in the carboxyl region of TcpA in surface-exposed regions of TCP fibres. Comparison of the genetic diversity among V. cholerae isolates at the tcpA locus with that of aldA, another locus within the VPI, and mdh, a chromosomal locus, revealed that tcpA sequences are far more diverse than these other loci. Most likely, this diversity is a reflection of diversifying selection in adaptation to the host immune response or to CTXphi susceptibility. An assessment of the functional properties of the variant tcpA sequences in the non-01 V. cholerae strains was carried out by analysing whether these strains could be infected by CTXphi and colonize the suckling mouse. Similar to El Tor strains of V. cholerae 01, in vitro CTXphi infection of these strains required the exogenous expression of toxT, suggesting that in these strains ToxT regulates TCP expression and that these TcpA variants can serve as CTXphi receptors. All the V. cholerae non-01 serogroup isolates tested were capable of colonizing the suckling mouse small intestine, suggesting that the different TcpA variants could function as colonization factors.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据