目的研究霍乱弧菌埃尔托型(EVC)新类型溶源性噬菌体(CTXφ)和核心区不含ctxAB基因的溶源性噬菌体(nct-CTXφ)基因组的结构。方法采用基因扩增、测序及序列生物信息学等方法进行观察与分析。结果在我国EVC中,存在仅携带古典型(class)nct-CTXφ、CTXφ或埃尔托型(ET)CTXφ基因组类型,并发现nct-CTXclassφ和CTXETφ共存、nct-CTXnewETφ和CTXclassφ共存的新类型。CTXφ和nct-CTXφ基因组zot基因3′末端,60bp序列中40%位点不同,推测的氨基酸序列中60%位点不同。class、ET和newET类型ig 1、rstR和ig 2基因序列同源性分别为77.0%~97.4%,10.4%~17.9%,9.6%~64.8%,RstR同源性9.2%~24.1%。CTXφ基因组均位于染色体TLC基因簇附近。上述不同类型EVC的tcpA、TcpA、ctxA、ctxB、CtxA和CtxB与GenBank中EVC和O139群产毒株的同源性分别〉99%,99%,99%,98%,98%和96%。结论首次在EVC中发现nct-CTXclassφ和CTXETφ、nct-CTX^newET φ和CTX^classφ共存的新类型。
Objeetive To study on structures of new types of CTXφ and net- CTXφ genomes of EI Tor biotype vibrio cholerae. Methods PCR, sequencing and sequence analysis were conducted. Results Only net - CTX^clamφ CTX^clamφ or CTX^ETφ genome type, net - CTX^clamφ and CTX^clamφ nct - CTX^clamφ and CTX^ETφ genomes coexisted types in El Tor strains isolated from China were found. Different rates of last 60 bp of zot gene and Zot of CTXφ and net - CTXφ were 40 % and 60%. Identities of ig1, rstR, ig2 gene and RstR of class,ET and newET types were 77.0% -97.4%, 10.4% - 17.9%, 9.6 % - 64.8 %, and 9.2 % - 24.1% differentially. Different types of CTXφ genome were found near TLC duster. Identities of tcpA, TcpA, ctxA, ctxB, CtxA, and CtxB of strains in this study with others toxic EVC and O139 VC were over 99%, 99%, 99%, 98%, 98%, and 96%. Conclusion net - CTX^clamφ and CTX^ETφ net - CTX^clamφETφ and CTX^clamφ genomes coexisted types in EI Tor were found first.