RESUMO
Objective To study the nucleotide and amino acid sequences of norovirus G Ⅱ.4/Sydney 2012 variants,in China.Methods Twenty-two stool specimens,confirmed as G Ⅱ.4/Sydney 2012-positive were collected from Beijing in the winter of 2012-2013.RT-PCR was performed to target the complete capsid gene.G Ⅱ.4/Sydney 2012 strains from other regions in China were searched and obtained from the GenBank.Nucleotide and amino acid sequences of G Ⅱ.4/Sydney 2012 strains were analyzed,using the CLUSTAL X (Version 1.83)and followed by phylogenetic analysis using Mega version 5.1.Results The complete major capsid nucleotide sequences of thirty-eight G Ⅱ.4/Sydney 2012 strains from seven regions in China were obtained.The VP1 nucleotide and amino acid sequences diversity were 0.1％-3.3％ and 0-3.1％,respectively.Result from phylogenetic analysis demonstrated that the G Ⅱ.4/Sydney 2012 variant shared a common ancestor with both the dominant norovirus G Ⅱ.4 variants Apeldoom 2008 and the New Orleans 2009.G Ⅱ.4/Sydney 2012 variants appeared to have had two A/D/E site combinations at the amino acid level,TSRN-GTT-SNT and TSRN-STT-SNT.Conclusion G Ⅱ.4/Sydney 2012 variant had been circulating in many regions in China.There seemed a high nucleotide and amino acid identity among G Ⅱ.4/Sydney 2012 strains collected from China.G Ⅱ.4/Sydney 2012 variants showed different A/D/E site combination from other pandemic G Ⅱ.4 variants.
RESUMO
Objective To study the composition of variant and point mutations of Norovirus GⅡ.4 in Guiyang regions.Methods From June to November 2010,cases information and fecal specimens were collected from guard-hospitals in Guiyang regions,who had caught the acute-gastroenteritis.Noroviruses in specimens were detected by a real-time reverse transcription polymerase chain reaction(real-time RT-PCR),and then partial genotyped norovirus-positive clinical samples (in random) were cloned and sequenced in VP1 gene code.Furthermore,the gene sequences were compared with the published variants at home and abroad of norovirus(GⅡ.4),including the phylogenetic analyses of genomes and variation of amino acids within individual sites.Results Those 267 specimens were GⅡ-norovirus-positive(62.68％) in 426 clinical samples.There were nine GⅡ.4-norovirus-positive VP1 gene-sequences available,and two subtype-norovirus variants (GⅡ.4 2008a and G Ⅱ.4 2008b variant) were epidemic in 2010,Guizhou province.The homology between and in subgroups were 95.90％-96.72％ and 99.45％-100％.Two amino acids within individual sites were apt to mutate.Conclusion Norovirus GⅡ genotype were predominant in summer and fall acute gastroenteritis in 2010 for Guiyang regions,and the variants were diversity.
