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目的 了解人甲型流感病毒H9N2亚型毒株的来源及从分子生物学角度来弄清不同宿主来源的H9N2亚型毒株间相互关系。方法 病毒在鸡胚中传代 ,从收获的尿囊液中提取病毒粒RNA ,通过逆转录合成cDNA。cDNA通过PCR进行扩增 ,接着PCR产物用纯化试剂盒进行纯化。而后 ,RNA序列测定是采用双脱氧链末端终止和克隆法。最后用MegAlign( 1.0 3版 )和Editseq( 3.69版 )软件进行种系发生学分析。结果 从中国所分离出的H9N2亚型毒株。它们的HA1与HA2间裂解部位的氨基酸序列均为R S S R ,除一株鸽病毒其HA蛋白分子上仅含 7个潜在的糖基化位点外 ,而其余的均含 8个。 6株H9N2毒株HA蛋白分子上氨基酸序列有 2 - 16个不同 ,这些不同分布在 2 4个不同的位点上。近来在中国同时流行着多种HA基因系的H9N2亚型毒株。结论 人甲型流感病毒H9N2亚型毒株可能性最大来自鸡的H9N2毒株 ,而不是来源于鸽的H9N2毒株。但 ,H9N2毒株是否具有人传人能力 ,至今仍不清楚。在中国同时流行着多种HA基因系的H9N2毒株。
Objective To understand the origin of H9N2 subtype strains of human influenza A virus and to clarify the relationship between H9N2 subtypes strains from different host sources from the perspective of molecular biology. Methods Viruses were passaged in chicken embryos and virion RNA was extracted from harvested allantoic fluid and cDNA was synthesized by reverse transcription. The cDNA is amplified by PCR and then the PCR product is purified using a purification kit. RNA sequencing then uses dideoxy chain termination and cloning. Finally phylogenetic analysis was performed using MegAlign (version 1.0 3) and Editseq (version 3.69) software. Results H9N2 subtype strains isolated from China. The amino acid sequence of the cleavage site between HA1 and HA2 was RsSR, except that there was only 7 potential glycosylation sites on the HA protein molecule of a pigeon virus, while the rest contained 8. The 6 strains of H9N2 strain HA protein molecules have 2 - 16 different amino acid sequences, these differences are distributed in 24 different sites. Recently, a number of H9N2 subtypes of HA gene lines have been prevalent in China at the same time. Conclusions Human influenza A virus H9N2 subtype strain is most likely to be derived from the H9N2 strain of chickens rather than from the pigeon-producing H9N2 strain. However, whether the H9N2 strain has human-descendant capabilities remains unclear. H9N2 strains of various HA gene lines are also prevalent in China.