RESUMEN
<p><b>OBJECTIVE</b>To determine the sequence of S2 gene of SARS-associated coronavirus (SARS-CoV) GD322 and analyze the phyletic evolution of S2 gene.</p><p><b>METHOD</b>S2 gene fragment was amplified from SARS-CoV GD322 genome with RT-PCR and ligated to pGEM-T vector for sequence analysis after transformation of the plasmid into E. coli DH5a. The variability of S2 genes and S2 proteins from 12 strains isolated in the early, intermediate and advanced stages of the SARS outbreak were analyzed and the phylogenetic tree was constructed with Lasergene, Clustal X, DNAman and Treeview. T cell antigen epitopes of S2 protein were predicted on the basis of Internet database.</p><p><b>RESULT</b>With the epidemic spread of SARS-CoV, the S2 genes of the virus tended to become stable. Homology of S2 genes of SARS-CoV isolated in advanced stage of the outbreak reached 99.9%. Prediction of T cell antigen epitope showed that mutation at the 57th amino acid effected T cell antigen epitope.</p><p><b>CONCLUSION</b>S2 gene of GD322 SARS-CoV is relatively stable during the epidemic spread of the virus, and mutation at the 57th amino acids of S2 protein may affect the T cell antigen epitope.</p>
Asunto(s)
Humanos , Escherichia coli , Genética , Variación Genética , Filogenia , Mutación Puntual , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo , Genética , Análisis de Secuencia de ADN , Síndrome Respiratorio Agudo Grave , Virología , Proteínas del Envoltorio Viral , GenéticaRESUMEN
<p><b>OBJECTIVE</b>To construct the cDNA subclones spanning the entire genome of dengue 2 virus NGC strain for further construction of full-length infectious viral cDNA clone.</p><p><b>METHODS</b>Two pairs of primers were designed according to the restriction endonuclease sites in the viral genome of dengue 2 virus NGC strain. After viral RNA extraction from the brain of infected new-born mice, two parts of full-length viral cDNA were amplified by long RT-PCR and cloned into the vector pCR-XL-TOPO. The partial sequence of the recombinant plasmid was determined.</p><p><b>RESULTS AND CONCLUSION</b>Sequence analysis and digestion with restriction enzymes demonstrated that the two cDNA subclones were specific for dengue 2 virus NGC strain, suggesting the successful construction of the two cDNA subclones of dengue 2 virus NGC strain.</p>
Asunto(s)
Animales , Ratones , Animales Recién Nacidos , Encéfalo , Virología , Clonación Molecular , ADN Complementario , Genética , ADN Viral , Genética , Dengue , Virología , Virus del Dengue , Clasificación , Genética , Genoma Viral , ARN Viral , Genética , Recombinación Genética , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Increased recognition of human parvovirus B19,as a significant human pathogen has resulted in intensive researches to understand the pathogenesis of B19 infection,to elucidate the nature of Th1-mediated cellular immune response,to improve diagnostic strategy that is deployed to detect B19 infection and blood-product contamination,and to lay a foundation that should contribute to the development of an effective vaccine to prevent B19 infection.In this review,the biologic characteristics and the pathogenesis of human parvovirus B19,and B19-related manifestations as well as laboratory diagnostic methods for B19 infection were comprehensively discussed.