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目的了解盐城市禽流感H7N9病毒株HA基因和NA基因分子进化特征,为更好预防和治疗人感染禽流感H7N9病例提供科学依据。方法通过荧光定量PCR方法对标本进行流感病毒分型检测,对禽流感H7N9病毒荧光PCR阳性的标本,采用一步法RT-PCR方法对H7N9病毒HA基因和NA基因全长编码区进行扩增,扩增产物经纯化测序,采用相应的生物信息软件进行核苷酸及氨基酸序列比对及基因种系进化特征分析。结果盐城市禽流感H7N9病毒株HA基因和NA基因有着独特的进化方式,A/JSYC/1/2016(H7N9)病毒株HA裂解位点附近氨基酸序列为PEIPKGR/GL,属于低致病性禽流感病毒。HA基因编码蛋白受体结合位点出现了G186V、Q226L氨基酸位点的变化,增强了病毒对人的感染能力,NA基因编码蛋白主要可能的神经氨酸酶抑制剂耐药位点未发生E120G、R153K、H276Y、R294K的变异。结论 2016年盐城市禽流感H7N9病毒株HA基因和NA基因处于基因点突变的抗原漂移变化中,某些变异位点具备了感染人的某些分子特征。
Objective To understand the molecular evolution characteristics of HA gene and NA gene of H7N9 strain of avian influenza in Yancheng and provide a scientific basis for better prevention and treatment of human H7N9 infection. Methods Fluorescent quantitative PCR was used to detect the influenza virus type in specimens. The H7N9 virus HA gene and NA gene full-length coding region were amplified by one-step reverse transcriptase polymerase chain reaction (RT-PCR) The purified product was purified and sequenced, and the nucleotide and amino acid sequence alignment and evolutionary characteristics of the germline gene were analyzed by corresponding bioinformatics software. Results The HA gene and NA gene of H7N9 strain of Yancheng City had a unique evolutionary pattern. The amino acid sequence near the HA cleavage site of strain A / JSYC / 1/2016 (H7N9) was PEIPKGR / GL, which belonged to low pathogenic avian influenza virus. HA gene encoding protein binding site appeared G186V, Q226L amino acid site changes, enhance the ability of the virus in humans, NA gene encoding protein major possible neuraminidase inhibitor drug-resistant sites did not occur E120G, Variation of R153K, H276Y, R294K. Conclusion In 2016, the HA gene and NA gene of H7N9 strain of avian influenza in Yancheng City were under the change of antigenic drift of point mutations. Some of the variation sites possessed some molecular characteristics of infecting humans.