小肠结肠炎耶尔森菌尿素酶基因多态性及尿素酶活性分析

Analysis on polymorphism of Yersinia enterocolitica urease gene and urease activity

目的了解小肠结肠炎耶尔森菌尿素酶基因的多态性以及不同致病力菌株尿素酶活性之间的关联性。方法选取43株不同致病能力的小肠结肠炎耶尔森菌用PCR扩增尿素酶基因并进行序列测定。连同4株NCBI上尿素酶基因参考序列一起进行比对和构建聚类树。同时选取8株不同致病力的小肠结肠炎耶尔森菌进行尿素酶活性实验。结果在低致病性小肠结肠炎耶尔森菌中,全部的18株O∶3血清型菌株的尿素酶基因7个开放读码框(ureABCEFGD)的基因序列完全一致;在全部17株O∶9血清型菌株中,尿素酶基因7个开放读码框(ureABCEFGD)的基因序列完全一致的有16株,仅1株2/O∶9(NX1997-IE419)与其他血清型菌株的尿素酶基因序列不同;高致病性的O∶8血清型小肠结肠炎耶尔森菌以及非致病菌的尿素酶基因序列与低致病性O∶3、O∶9血清型菌株的尿素酶基因序列不同且各菌株之间基因序列差异也较大。尿素酶活性实验显示不同致病能力的小肠结肠炎耶尔森菌尿素酶活性存在多样性,无明显的规律发现。结论低致病性O∶3、O∶9血清型的小肠结肠炎耶尔森菌的尿素酶基因分别表现出高度的保守性,NX1997-IE419的尿素酶基因可能是由O∶3血清型小肠结肠炎耶尔森菌的尿素酶基因演变而来。高致病性的1B/O∶8小肠结肠炎耶尔森菌及非致病性小肠结肠炎的尿素酶基因相对不保守。尿素酶活性试验提示我们小肠结肠炎耶尔森菌的尿素酶活性大小与其致病性的强弱可能无关联。

The poiymorphism of Yersinia enterocolitica urease gene and the correlation of urease activation between dif- ferent pathogenicity strain was investigated in this study. We chose 43 Yersinia enterocolitica strains, which had different path- ogenicity. After PCR and sequencing, we conducted sequence alignment with 4 NCBI reference sequences and constructed clus- ter tree. Then we chose 8 Yersinia enterocolitica strains which had different pathogenicity to perform urease activity experi- ment. It was found that in low pathogenic Yersinia enterocolitica, seven ORF of urease gene of all 18 serotype O ： 3 strain made no difference. Seven ORF of urease gene of 16 serotype O ： 9 strain made no difference except NX199？-IE419（2/ ： 9）. Sequence of high pathogenic strain and none pathogenic strain were not conserved, not only between low pathogenic strains but also between themselves. In urease activity experiment, we found that urease activity of Yersinia enterocolitica that had differ- ent pathogenic capability was not the same. It had no relationship between pathogenicity and urease activation. The results demonstrated that seven ORF of urease gene complex were highly conserved among serotype O ： 3 strain and serotype O ： 9 strain respectively. Urease gene of NX1997-IE419 may evolve from serotype O ＇ 3 strain. Sequences of high-pathogenic strain and non-pathogenic strain were not conserved. Urease activity experiment suggested that pathogenicity and urease activation might not have correlation.