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To select the adaptive strain of Dengue-III virus D9964 strain (China strain) in KMB17 cells, elucidate the biological characteristics and proliferation kinetics of adapted strain,and to lay the foundation for the development dengue inactivated vaccine and attenuated live vaccine. Dengue-III virus D9964 strain was firstly identified by amplification of the type-specific gene segment of dengue virus by RT-PCR, and the titer was determined. The virus was then subcultured in KMB17 cells with 4.0 MOI till completely adaptive to multiply in cell S. After subculturing in KMB17 cells for 10 consecutive passages, the adapted strain was screened, and purified through plaque. Virus titer of each passage was measured by microtitrimetry, and the antigenicity was detected by IFA. The purified virus RNA extraction of 3-8 day cultured from KMB17 cells, was performed to detect the proliferation kinetics of adapted strain. The results showed that after continuous subculture, dengue-III virus D9964 (China) strain could stably proliferate in KMB17 cells, a highly puried virus adapted strain was obtained through plaque purification. Purified strain maintained the good antigenicity with a highest replicating activity during the 5th-6th day.

To analyze the genomic sequence characteristics of a human Echovirus 9(ECHO-9) strain isolated from a child with Hand-foot-mouth disease (HFMD) in Kunming, Yunnan Province, in 2010. The complete genome sequence of a human echovirus 9 strain, MSH-KM812-2010 was determined. As other human enterovirus, its genome was 7,424 nucleotides (nts) in length and encoded for 2,203 amino acids (aas). In comparison to other human enteroviruses, MSH-KM812-2010 strain had the highest homology with other strains of human echovirus 9 in structural genomic regions and more homologous to other serotypes of B specie than to human echovirus 9 in non-structural genomic regions. Phylogenetic analysis based on complete VP1 gene revealed that the sequences of human echovirus 9 segregated into three distinct clades A, B and C with more than 15. 0% diversity between clades. All Chinese isolates belonged to the same clade. RDP3 and Blast revealed evident recombination in non-structural genomic regions. This report is the first to, describe the complete genome of the human echovirus 9 in China and provide an overview of the diversity of genetic characteristics of a circulating human echovirus 9.

To investigate E6 and E7 gene variations of human papillomavirus type 16 in Yunnan Province, DNA was extracted from 2000 gynecological outpatient samples. For Human papillomavirus (HPV) genotyping, the genomic DNA was first amplified by the consensus MY09/MY11 primer pair followed by nested PCR with GP5+/GP6+ primers, then the PCR products were subjected to direct DNA sequencing. A total of 20 HPV-16 viral DNAs were identified. E6 and E7 genes of HPV-16 viral DNA were then amplified using E6 and E7 specific primers, the PCR products were purified and sequenced. The results showed that mutations were found at nucleotide position 178 of HPV-16 E6 gene in 10 cases,the mutation rate was 50%; For HPV-16 E7 gene, the mutations were found at nucleotide position 647 in 10 cases; the mutation rate was 50%. Phylogenetic analysis showed that Asian (As) variants of HPV-16 were predominated in Yunnan, China. None of African-1, African-2 variants of HPV-16 was found in this region.