AIM: To investigate the distribution of 12 high-pathogenicity island (HPI) genes and the relation between HPI genes and expression of yersiniabactin (Ybt) in enteroaggregative E.coli(EAggEC) isolated from Chinese diar...AIM: To investigate the distribution of 12 high-pathogenicity island (HPI) genes and the relation between HPI genes and expression of yersiniabactin (Ybt) in enteroaggregative E.coli(EAggEC) isolated from Chinese diarrhea patients.METHODS: The distribution of 12 HPI genes was investigated by PCR and DNA hybridization in two prototype strains of EAggEC, EAggEC 17-2, EAggEC O42, and 6 clinical EAggEC isolates from China. The production of siderophore Ybt in HPI-positive strains was detected by reporter gene bioassay to determine the relation between HPI genes and expression of Ybt. Flow cytometry was used to detect fluorescent signal of the reporter strain that could designate production of Ybt.RESULTS: Seven strains were HPI-positive and one strain was HPI-negative. Six of the seven HPI-positive strains were inserted into asnT-tRNA site. Moreover, seven EAggEC HPI-positive strains revealed enhanced fluorescence signal but the EAggEC HPI-negative strain did not. However, there was a difference in Ybt expression condition and level among these seven EAggEC HPI-positive strains. Although UFT073 strain, the prototype strain of uropathogenic E.coli(UPEC), carried the complete HPI core part, we did not detect the expression of Ybt in it.CONCLUSION: EAggEC HPI-positive strains can express the Ybt system, but the presence of HPI core part does not mean the functional expression of Ybt.展开更多
The aim of this study is to carry out genotyping of 61 Y. pestts strmns tsolated trom lwarmota baibacina-Spermophilus undulates Plague Focus of Tianshan Mountains in China. Primer pairs targeting the 22 DFRs were desi...The aim of this study is to carry out genotyping of 61 Y. pestts strmns tsolated trom lwarmota baibacina-Spermophilus undulates Plague Focus of Tianshan Mountains in China. Primer pairs targeting the 22 DFRs were designed for detecting the genotypes of 61 strains. As a result, 61 strains of Y. pestis were divided into four genotypes 1, 2, 3, and 4. Genotypes 1, 2 and 3 were found from west part in Northern Tianshan Mountains Plague Focus, but type 1 was only from Nileke county. The type of strains from Aheqi was different from those of Atushi counties in Southern Tianshan Mountains and similar to strains in Northern Tianshan Mountains Plague Focus. The type 4 distributed over Atushi county, which was identical with that of strains from Marmota caudae Plague Focus of the Pamiri Plateau. It is concluded that geonotyping is identical with ecotyping made by Shuli Ji. Tianshan Mountains Plague Focus and Marmota caudae Plague Focus of the Pamiri Plateau have a cross spreading profile.展开更多
基金Supported by the National Basic Research Program of Ministry of Science and Technology of China, No. G1999054101
文摘AIM: To investigate the distribution of 12 high-pathogenicity island (HPI) genes and the relation between HPI genes and expression of yersiniabactin (Ybt) in enteroaggregative E.coli(EAggEC) isolated from Chinese diarrhea patients.METHODS: The distribution of 12 HPI genes was investigated by PCR and DNA hybridization in two prototype strains of EAggEC, EAggEC 17-2, EAggEC O42, and 6 clinical EAggEC isolates from China. The production of siderophore Ybt in HPI-positive strains was detected by reporter gene bioassay to determine the relation between HPI genes and expression of Ybt. Flow cytometry was used to detect fluorescent signal of the reporter strain that could designate production of Ybt.RESULTS: Seven strains were HPI-positive and one strain was HPI-negative. Six of the seven HPI-positive strains were inserted into asnT-tRNA site. Moreover, seven EAggEC HPI-positive strains revealed enhanced fluorescence signal but the EAggEC HPI-negative strain did not. However, there was a difference in Ybt expression condition and level among these seven EAggEC HPI-positive strains. Although UFT073 strain, the prototype strain of uropathogenic E.coli(UPEC), carried the complete HPI core part, we did not detect the expression of Ybt in it.CONCLUSION: EAggEC HPI-positive strains can express the Ybt system, but the presence of HPI core part does not mean the functional expression of Ybt.
文摘The aim of this study is to carry out genotyping of 61 Y. pestts strmns tsolated trom lwarmota baibacina-Spermophilus undulates Plague Focus of Tianshan Mountains in China. Primer pairs targeting the 22 DFRs were designed for detecting the genotypes of 61 strains. As a result, 61 strains of Y. pestis were divided into four genotypes 1, 2, 3, and 4. Genotypes 1, 2 and 3 were found from west part in Northern Tianshan Mountains Plague Focus, but type 1 was only from Nileke county. The type of strains from Aheqi was different from those of Atushi counties in Southern Tianshan Mountains and similar to strains in Northern Tianshan Mountains Plague Focus. The type 4 distributed over Atushi county, which was identical with that of strains from Marmota caudae Plague Focus of the Pamiri Plateau. It is concluded that geonotyping is identical with ecotyping made by Shuli Ji. Tianshan Mountains Plague Focus and Marmota caudae Plague Focus of the Pamiri Plateau have a cross spreading profile.
