Molecular evolution of human influenza H3N2 virus hemagglutinin genes in Guangdong China / 病毒学报

The molecular characterization and phylogenetic analysis of hemagglutinin (HA) genes of human influenza H3N2 viruses in Guangdong, China from 2007 to 2010 were studied in this study. By space-time sampling of strains, the HA genes of H3N2 strains from Guangdong were sequenced and searched from Internet, and then the variation and evolution of HA genes were conducted by Lasergene 7.1 and Mega 5.05 and evolutionary rates were analyzed by epidemiological data. The phylogenetic tree was established by alignment of 17 Guangdong strains and 26 global reference strains. Ks rates and Ka rates of HA genes were 2.06 x 10(-3)-2.23 x 10(-3) Nt/Year and 1.05 x 10(-3)-1.21 x 10(3) Nt/Year during 2007-2010, while the velocity of HA1 evolution of Ka was 3. 13 times than that of HA2 evolution. Compared with HA of vaccine strain A/Perth/16/2009, the genetic homologies of Guangdong strains in 2009 reached to 98.8%-99.7% and of Guangdong strains in 2010 reached to 98.0%-98.4%. There were some amino acid substitutions in five epitope regions of HA1 during 2007-2010, especially in B region (N160K) and D region (K174R/N); the K189E/N/Q and T228A in RBS (receptor-binding site) occurred in 2010 as two glycoproteins sites substituted impacted on the HA1 antigenicity. The antigenicity of epidemic H3N2 strains in 2010 was to some degree different that of the vaccine strain A/ Perth/16/2009. According to that there were variations of B and D epitopes and two sites of RBS and two glycoprotein in Guangdong H3N2 HA1 genes, WHO/ CDC should recommend new representative strains during 2011-2012 influenza seasons if H3N2 HA genes further evolve in the near future.

Molecular typing of Listeria monocytogenes isolated from foodstuff in Guangdong province by pulsed-field gel electrophoresis / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish molecular typing of Listeria monocytogenes isolates by pulsed-field gel electrophoresis (PFGE) for studying the epidemiologic characteristics of Listeria monocytogenes isolated from foodstuff in Guangdong province and to build up PFGE typing database of Listeria monocytogenes isolates for identifying the infectious resource of the outbreaks and other epidemiologic investigation.</p><p><b>METHODS</b>"Standardized Protocol for Molecular Subtyping of Listeria monocytogenes by PFGE" was followed. BioNumerics software was applied on image analysis, database establishment, comparative and corresponding analysis.</p><p><b>RESULTS</b>107 Listeria monocytogenes isolates were typed by PFGE, 41 PFGE types were observed among the isolates. The PFGE types were dispersive among these isolates. Listeria monocytogenes isolates were most frequently isolated in raw chicken while the most PFGE types were found in this type of food. The positive rate was relatively high in cold and iced foods. Only 1-2 DNA fragment difference occurred in 26 Listeria monocytogenes isolates by PFGE, so high degree of relatedness remained among these isolates. There were unique PFGE patterns in the regions of Shaoguan and Huizhou. From time to time, a number of isolates remained close relationship.</p><p><b>CONCLUSION</b>PFGE typing of the 107 Guangdong Listeria monocytogenes isolates demonstrated relative genetic diversity but a number of the isolates showed close relatedness.</p>

Molecular Evolution of Guangdong Influenza Virus Isolates in Influenza Outbreak in 1996 / 中国病毒学

It was demonstrated that there was significantly antigeni c drift in the influenza virus strains from Guangdong in 1996. It was the molecu lar basis of the variation on A、B、C、D and E domain encoded by HA gene, especi ally on A、C and E domain while the change of receptor binding domain played the slight roles in the 1996 influenza outbreak. In the other hand, the variation of No 145 and No 193 encoded by HA gene resulted in biological-feature changes of epidemical influenza isolates, which could be isolated and cultured by MDCK c ell-lines, but difficultly by embryonated-eggs.