ABSTRACT
@#Abstract: Objective To understand the phenotypic and genetic characteristics of Yersinia pestis strains isolated from Himalayan marmot natural focus area and domestic rat plague focus area in southern China, and provide reference for mastering the pathogenic characteristics of Yersinia pestis of two plague foci. Methods A total of 412 of Yersinia pestis strains isolated from Himalayan marmot plague focus and domestic rat plague focus of southern China were subjected to to sorbitol fermentation assays, virulence factor, different region (DFR) typing, and clustered regularly interspaced palindromic repeats (CRISPR) typing. Results The biochemical types of Y. pestis from the two plague foci showed distinct regional distribution features. Five biochemical phenotypes were identified in Yersinia pestis isolated from Himalayan marmot natural focus area, while only one biochemical phenotype was identified in strains isolated from the domestic rat plague focus of Southern China. Most of the Yersinia pestis isolated from the two plague foci were capable of producing the virulence factors of Fl and PstI. Among the strains from Himalayan marmot focus, 70.53% (201/285) were VW-positive, 75.09% (214/285) were Pgm-positive, 20.00% (57/285) of the strains were Pgm-negative, and 5.26% (15/285) were Pgm mixed-type strains. Among strains from domestic rat plague focus of southern China, 37.80% (48/127) were VW-positive, 29.13% (37/127) were Pgm-positive, 58.27% (74/127) were Pgm-negative, and 12.60% (16/127) were Pgm mixed-type strains. DFR typing revealed 22 genotypes of Y. pestis from the Himalayan marmot plague focus, with the main genotypes being type 5, 7, 8, 10, 19, 32 and 49. All strains from domestic rat plague focus area in southern China belonged to type 9. CRISPR typing revealed that all strains from the Himalayan marmot natural focus were classified into 7 CRISPR gene clusters and 14 CRISPR genotypes, with the main genotypes being G7, G22, G26-a1'and G22-A1'. All strains from domestic rat plague focus area in southern China belonged to CRISPR genotype G30, with the gene cluster being Ca8. Conclusions The phenotypes and genotypes of the Yersinia pestis of Himalayan marmot plague focus are diverse, with an obvious characteristics of geographical distribution. The phenotype and genotype of the Yersinia pestis of domestic rat plague focus of Southern China are single. DFR and CRISPR genotyping methods with phenotypic characteristics can effectively identify the Yersinia pestis isolated from the two plague foci, thereby meeting the needs of identification and traceability research.
ABSTRACT
@# Objective: To investigate the mechanisms of miR-375 affecting the proliferation and invasion of hepatoma cells via targeting YAP (Yes-associated protein). Methods: The cancerous tissues and corresponding para-cancerous tissues of 70 patients with hepatocellular carcinoma (HCC) who underwent surgical resection at the Second Affiliated Hospital of Henan University of Traditional Chinese Medicine from January 2015 to December 2016, as well as the hepatoma cell lines SMMC-7721, Hb611, HepG2 and BEL-7405 were collected for this study. qPCR method was used to detect the expression level of miR-375 in collected HCC tissues and different hepatoma cell lines; Dual luciferase reporter gene assay was used to verify the interaction between miR-375 and YAP; The relationship between miR-375 and clinicopathological features of HCC patients was also analyzed; MTT assay was used to detect the effect of miR375 on the proliferation of hepatoma cells; Transwell invasion assay was used to detect the invasive ability of hepatoma cells after inhibiting the expression of miR-375; Western blotting was used to detect the expression of YAP in HepG2 cells. The nude mouse model of subcutaneously transplanted xenograft was established, and the tumor volume and mass of transplanted hepatoma cells were detected after inhibiting the expression of miR-375. The expression of YAP in xenograft of nude mice was detected by immunohistochemistry and Western blotting. Results: The expression of miR-375 and YAP in HCC tissues was significantly higher than that in para-cancerous tissues (all P<0.05). The expression of miR-375 in HepG2 cells was the highest (P<0.05). miR-375 could specifically bind to the 3' UTR of YAP and regulate the expression activity of YAP. After inhibiting the expression of miR-375, the proliferation and invasion abilities of HepG2 cells were reduced (all P<0.05); The tumor volume and mass of transplanted xenografts were significantly reduced (both P<0.05); The expression of YAP protein in the transplanted xenografts was down-regulated (P<0.05). Conclusion: miR-375 plays an important role in the occurrence and development of liver cancer, and can influence the malignant biological behaviors of hepatoma cells by targeting and regulating the expression ofYAP.