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1.
为了解2008~2009年珠海市H3N2亚型流感病毒HA1基因变异情况,选择珠海市2008~2009年期间不同时间点的经狗肾传代细胞(MDCK)培养分离的H3N2亚型流感毒株20株,提取病毒RNA,通过RT-PCR扩增HA1基因片段,将产物纯化并测序,推导氨基酸序列,进行基因进化特性分析。与同时期的疫苗株比较,2008年珠海市流行的H3N2亚型流感毒株HA1区抗原决定簇的氨基酸位点变异数少于4个;2009年珠海市流行的H3N2亚型流感毒株除09-0056外,HA1区存在5个位于抗原决定簇内的变异氨基酸位点。2008年H3N2亚型流感毒株的HA1区的糖基化位点与疫苗株一致;2009年H3N2亚型流感毒株HA1区丢失第144位糖基化位点。2008~2009年H3N2亚型流感毒株RBS氨基酸序列未见明显变异。与2008年H3N2亚型流感毒株比较,2009年H3N2亚型流感毒株HA1区抗原决定簇内存在多个位点的氨基酸替换。这些说明2008年珠海市流行的H3N2亚型流感病毒不是新变种;2009年流行的H3N2亚型流感病毒为新的变异株,这可能是H3N2亚型流感病毒在2009年6-9月为珠海地区季节性流感流行优势株的原因。  相似文献   

2.
【目的】为了解中国地区2009?2015年甲型H1N1流感病毒流行态势,分析血凝素(Hemagglutinin,HA)基因的变异情况及其遗传进化特征。【方法】汇集国家流感中心2009?2015年流感周报的流感流行数据,分析甲型H1N1流感的流行病学特征;从全球共享禽流感数据倡议组织数据库及美国国家生物技术中心数据库下载甲型H1N1流感病毒HA基因序列,采用生物学软件进行系统进化和遗传特性的分析。【结果】2009?2015年全国共发生4次甲型H1N1流感的流行高峰。2009?2015年毒株与参考毒株A/California/07/2009(H1N1)的HA基因同源性逐年降低。遗传进化分析显示同一年份的毒株在系统进化树上基本呈现集中分布,2011年的毒株独立形成2个分支。分子特征表现为HA基因的4个抗原决定簇氨基酸位点均有变异,其中Ca区的203位、Sa区的163位和Sb区的185位氨基酸位点逐渐替换为新的氨基酸。除2010年与2012年,其他年份的毒株通过不同模型均得到正向压力选择HA氨基酸位点240。【结论】甲型H1N1流感在中国地区成为主要流行的亚型之一。HA基因与其编码的氨基酸逐年变异,未来进一步的流感监测能力还需加强。  相似文献   

3.
目的研究甲型流感病毒(H1N1)暴发流行以来中国各地甲型流感病毒血凝素(HA)的特征。方法搜索甲型流感病毒(H1N1)暴发流行以来中国各地报道的血凝素(HA)的氨基酸序列,比较当年不同时期血凝素(HA)的氨基酸序列的变化,并比较2009年报道的血凝素(HA)的氨基酸序列和2008年、2007年报道的血凝素(HA)的氨基酸序列作比较,以分析和前2年血凝素(HA)氨基酸序列相比所发生的变化。结果2009年中国各地甲型流感病毒(H1N1)的血凝素(HA)的氨基酸序列(人源)的同源性为99%-100%,但和2008年以及2007年的同源性非常低,分别为70%-77%和71%-90%。结论2009年暴发流行的甲型流感病毒(H1N1)的血凝素氨基酸序列较往年发生了很大程度的变异,这可能是今年甲型流感病毒(H1N1)暴发流行的主要原因。  相似文献   

4.
新发甲型H1N1流感病毒HA分子的变异分析   总被引:1,自引:0,他引:1  
目的:从分子进化水平上分析流感的起源及发展问题,研究目前爆发的H1N1病毒的HA分子的变异行为.方法:以GenBank公布的甲型流感H1N1病毒血凝素(hemagglutinin,HA)核酸序列和我国及世界范围内近几年来报告的H1N1流感病毒HA的核酸及氨基酸序列为研究对象,利用CLUSTAL 1.83和NetNGlyc 1.0等生物信息学软件对HA核酸和氨基酸序列进行了比对分析;将其糖基化位点、氨基酸序列和抗原决定簇与以往流感病毒进行了比较.同时,还将人源和猪源甲型H1N1流感病毒的HA氨基酸序列进行了序列比对和系统发育分析.结果:最新爆发的甲型H1N1流感病毒的HA除了在60,259,453,512位点高度保守区域与之前爆发的流感病毒一致外,在249位点新出现1个"-NTT-"的糖基化位点.发现所有的甲型病毒的氨基酸序列在8个氨基酸位点均发生改变,而8个氨基酸位点位于6个抗原抗原决定簇上.结论:糖基化位点的增加,氨基酸位点的改变导致抗原决定簇的改变,即抗原性漂移现象,都成为引起其传染性改变的重要原因.  相似文献   

5.
本文通过比较2011年分离培养的1株季节性甲型H1N1流行性感冒(简称流感)病毒(A/Shanghai/1167/2011(H1N1))与历年季节性甲型H1N1流感病毒的血凝素(HA)基因,追溯该病毒的基因变异与来源,探讨该毒株的出现对流感防控工作的意义.采用反转录-聚合酶链反应(RT-PCR)方法扩增病毒的HA和神经氨酸酶(NA)片段,并进行测序;应用分子生物学软件对获得的序列进行分析,绘制基因进化树;同时,通过血凝抑制试验检测2011年下半年健康人群中该流感病毒的抗体水平.结果显示,A/Shanghai/1167/2011(H1N1)的HA基因序列与世界卫生组织(WHO)2007~2008年季节性甲型H1N1流感病毒疫苗株A/Brisbane/59/2007(H1N1)最接近,同源性达99.2%,与新型甲型H1N1流感病毒A/California/07/2009疫苗株同源性仅为72.4%.其HA基因裂解位点为PSIQSR↓GLF,尚未出现高致病性的分子特征.HA片段共编码557个氨基酸,有9个潜在的糖基化位点,序列与2009年前WHO疫苗株A/NewCaledonia/20/1999(H1N1)、A/SolomonIslands/3/2006(H1N1)和/Brisbane/59/2007(H1N1)相比,分别有15、12和4处不同,这些差异分布在Sa、Sb、Ca1、Ca2、Cb 5个抗原决定簇的氨基酸差异分别有5、5和2处.该毒株在健康人群血清的抗体阳性率为34.33%,几何平均效价(GMT)为10.38.A/Shanghai/1167/2011(H1N1)是2011年出现在上海地区的一个季节性甲型H1N1流感病毒毒株,其抗原变异与既往季节性甲型H1N1流感病毒相比不大,但在以A(H1N1)pdm09为主要流行株的年份检测到散在发生的既往季节性甲型H1N1流感病毒毒株应当引起重视,其在人群中的抗体水平较低,易引起流行,需要提高对类流感人群中此种毒株的持续监测.  相似文献   

6.
因HA基因的头部重链区(HA1)是流感病毒的抗原位点和受体结合位点,所以了解流感病毒的HA1基因特性可以评估当前WHO推荐的疫苗株的预防效果。本文选取新余市2013~2014年通过狗肾传代细胞(MDCK)培养分离到的H1N1流感毒株12株,提取病毒RNA,反转录-聚合酶链反应(RT-PCR)扩增HA1基因片段。对序列分析发现2013~2014年新余市甲型H1N1流感病毒HA1基因序列与疫苗推荐株有较高的同源性,核苷酸同源性97.9%~98.5%。2013年的6株毒株HA1区与疫苗株比较,氨基酸变异位点7~11个,其中3株有2个变异位点在不同的抗原决定簇区。而2014年毒株单独集中在进化树的一支。以上提示,目前流感疫苗对2014年的流感人群仍有保护作用,对2013年的部分流行的H1N1预防效果有限;甲型H1N1爆发流行的可能性很大,应加强防控。  相似文献   

7.
在2009~2010年监测年度开展甲型H1N1流感病毒学监测并进行病原学分离鉴定,以及对血凝素基因(HA)和神经氨酸酶基因(NA)特性分析,研究其基因变异情况。采集了17 126份发热患者的鼻、咽拭子标本,采用逆转录实时荧光定量RT-PCR(Real-Time RT-PCR)进行核酸检测,其中甲型H1N1流感病毒核酸检测阳性4004份,总阳性率为23.38%。对阳性标本开展病毒分离,并对分离的甲型H1N1流感病毒的HA、NA基因序列进行测序。利用DNAStar软件对序列进行同源性分析发现与WHO推荐的疫苗株相比,山东省甲型H1N1流感流行株HA、NA基因同源性分别为96.9%~99.3%和99.1%~99.6%;利用Mega 4.0软件进行基因进化分析和氨基酸进化分析发现,与WHO推荐的疫苗株相比,山东省甲型H1N1流感流行株有21个血凝素基因的氨基酸发生替换,其中11个氨基酸位点位于抗原决定簇区,一个糖基化位点发生改变;有16个神经氨酸酶基因的氨基酸发生了替换,一个糖基化位点发生改变;未发生神经氨酸酶蛋白275位H→Y的替换。结果显示山东省甲型H1N1流感暴发流行株HA基因和NA基因均具有高度同源性,HA蛋白和NA蛋白均存在不同程度的氨基酸替换,部分流行株抗原决定簇和糖基化位点发生改变,所有病毒均对达菲类药物敏感。  相似文献   

8.
2005年在广东进行流行病学调查时分离到一株鹦鹉源禽流感病毒,经鉴定为H5N2亚型禽流感病毒(A/Parrot/Guangdong/268/2005)。该毒株的HA裂解位点附近的氨基酸序列为RETRGLF,只含有一个碱性氨基酸,符合低致病性禽流感病毒的HA裂解位点附近氨基酸序列的分子特征;与H5N2亚型禽流感代表毒株相比,该毒株HA和NA基因的糖基化位点、HA基因的受体结合位点编码区、NA基因的耐药性位点均未发生变异。将该毒株全基因组序列与GenBank已公布的19株H5N2亚型禽流感病毒株的相应序列进行比较分析并绘制系统进化树后发现:其与低致病性禽流感毒株A/Pheasant/NJ/1355/1998(H5N2)-like的亲缘关系最近,位于以A/Chicken/Pennsylvania/1/1983(H5N2)为代表的美洲进化分支。  相似文献   

9.
目的分析1株甲型H1N1流感达菲耐药病毒株的全基因特征,为指导流感临床治疗与防控提供依据。方法采用鸡胚进行病毒分离,提取病毒RNA,通过RT-PCR扩增其全基因组8个基因片段,测定核苷酸序列,利用生物信息软件拼接全基因组序列,绘制基因进化树并分析重要基因位点变异情况。结果 A/Fuzhou/SWL11609/2013(H1N1)流感毒株的8个节段基因均处于2013-2014年度进化簇中,且与A/California/07/2009(H1N1)疫苗株高度同源,8个基因同源性均在97.4%以上;其HA和NA基因与A/Hubei-Wuchang/SWL1322/2013(H1N1)达菲耐药株同源性最高,分别为100.0%和99.6%;初步判断该毒株未发生重配现象,其重要致病性基因位点未发生变异;NA基因中具有H275Y典型达菲耐药位点特征,缺失一个糖基化位点(N386K),降低了基因结构的稳定性,同时在V241I和N369K的作用下降低了病毒的适应性。结论本次研究的甲型H1N1流感达菲耐药病毒株表现为低致病性流感病毒特征,但具备较好的人传人能力,需进一步加强监测,谨防耐药株的广泛流行。  相似文献   

10.
2009年6月12日,江苏确诊首例甲型H1N1(2009)病例。通过细胞和鸡胚分离系统,我们分离到一株具有较高血凝活性的病毒,命名为A/Jiangsu/1/2009。为了跟踪病毒的变异情况,我们开展了病毒的全基因组测序工作,在此基础上对其血凝素基因(Haemagglutinin,HA)的遗传特性进行了详细研究。分离株HA蛋白不具有多碱基HA裂解位点,具有低致病性流感病毒特点。与参考株A/California/04/2009相比,分离株A/Jiangsu/1/2009HA蛋白的有4个氨基酸发生了突变,但都不在已知的抗原位点上。分离株有5个潜在糖基化位点,这与近年来古典猪H1N1和北美三源重配猪H1病毒完全一致,保留了古典猪H1的特点。与禽流感H1病毒相比,分离株HA蛋白受体结合位点上的E190D和G225D发生突变,这可能成为新甲型H1N1(2009)在人际间传播的一个重要分子基础。此外,其它受体结合位点上相关氨基酸同时具有人和猪流感病毒的特点。本研究首次对早期流行的甲型H1N1(2009)流感病毒的HA蛋白的分子遗传特征进行了详细研究,对进一步监测病原变异具有重要指导意义。  相似文献   

11.
A comparison of the evolutionary tree of new influenza A (H1N1) viruses to that of old H1N1 viruses which disappeared in 1957 was performed. The evolutionary trees of the hemagglutinin (HA) molecule based on amino acid sequences of the HA1 polypeptide were constructed with old and new H1N1 viruses isolated from 1947 to 1957 and 1986 to 2000, respectively. The evolutionary history of recent H1N1 viruses was similar to that of old H1N1 viruses just before the disappearance in two respects. Firstly, both viruses did not originate from the viruses of the previous H1N1 epidemic season but originated from the viruses branched off at the same point on the mainstream stem as the viruses of two H1N1 epidemic seasons earlier. Secondly, recent H1N1 viruses mainly circulating in Japan have a deletion at amino acid residue 134, located close to residue 131, which was deleted in old H1N1 viruses at the time of the disappearance. However, different from the evolutionary history of old H1N1 viruses, in the 1999/2000 H1N1 epidemic season, the H1N1 viruses which were located on the same lineage as the previous epidemic viruses were also isolated sporadically in Japan.  相似文献   

12.
In the second half of 2005, a large-scale outbreak of influenza in poultry and wild birds was caused by a highly pathogenic H5N1 influenza virus in Russia. The level of pathogenicity is a polygenic trait, and most individual genes contribute to the influenza A virus pathogenicity in birds, animals, and humans. The full-length nucleotide sequences were determined for H5N1 strains isolated in the Kurgan region (Western Siberia). The structure of viral proteins was analyzed using the deduced amino acid sequences. The receptor-binding site of hemagglutinin (HA) in strains A/chicken/Kurgan/05/2005 and A/duck/Kurgan/08/2005 was typical for avian influenza viruses and contained Glu and Gly at positions 226 and 228, respectively. The structure of the basic amino acid cluster located within the HA cleavage site was identical in all isolates: QGERRRKKR. According to the neuraminidase structure, all H5N1 isolates from the Kurgan region were assigned to the Z genotype. Amino acid residues typical for the avian influenza virus were revealed in 30 out of 32 positions of M1, M2, NP, PA, and PB2, determining the host range specificity. One of the strains contained Lys at position 627 of PB2. Isolates from the Kurgan region were shown to have a remantadine-sensitive genotype. Both strains contained Glu at position 92 of NS1, indicating that the virus is interferon-resistant. Phylogenetic analysis related the Kurgan isolates to subclade 2 of clade 2 of highly pathogenic H5N1 influenza viruses.  相似文献   

13.
Pandemic influenza H1N1 virus (A[H1N1]pdm09) emerged in 2009. To determine the phylogeography of A(H1N1)pdm09 in a single population, 70 strains of the virus were isolated from university students or trainee doctors at Tobetsu, Hokkaido, Japan, between September and December 2009. The nucleotide sequences of the HA1 region of the HA genes and described phylogenetic relationships of the strains circulating among them were analyzed. It was found that the 70 isolates could be phylogenetically separated into three groups and that two epidemics were caused by different groups of the virus. The three groups were also distinguishable from each other by three amino acid changes: A197T, S203T and Q293H. The substitution of S203T, which is located in the antigenic site, suggests antigenic drift of the virus.  相似文献   

14.
对2009 年长沙麓山国际学校流感暴发疫情进行实验室诊断, 并探索新分离的A(H1N1)亚型流感病毒血凝素(HA)的基因特性。对流感暴发疫情的25 份鼻/咽拭子标本进行RT-PCR检测和流感病毒分离, 然后利用CEQ?8000 Genetic Analysis System对病毒分离株(A/Yuelu/314/2009)进行测序, 测序结果提交至GenBank(登录号: FJ912843)并用ClustalX和Mega4.1软件进行序列分析。结果显示, 分离出A(H1N1)亚型流感毒株18株, 检出21份A(H1N1)亚型流感病毒核酸阳性; A/Yuelu/314/2009(H1N1) HA基因序列与2008~2009 年疫苗株(A/Brisbane/59/2007)比较显示: 核苷酸和氨基酸同源性均为99%, 有6个位点的氨基酸发生了变异(V148A、S158N、G202A、I203D、A206T、W435R), 其中一个S158N氨基酸变异位于B抗原表位, HA基因序列上共有潜在糖基化位点9 个(27、28、40、71、151、176、303、497、536), 与A/Brisbane/59/2007相同且氨基酸序列保守。本实验诊断出此次流感暴发疫情的病原体为A(H1N1)型季节性流感病毒, 研究还发现A/Yuelu/314/2009(H1N1)长沙分离株与A/Brisbane/59/2007 疫苗株基因序列比较显示并未形成一个新的变种, 推测是由于分离株与疫苗株之间基因特性的改变和人群对A(H1N1)亚型流感病毒免疫力降低导致了此次长沙麓山国际学校A(H1N1)亚型流感的暴发。  相似文献   

15.
对2005年11月8日安徽省铜陵市人民医院报告的一例孕妇不明原因肺炎病例的死亡病因进行研究。采集病人的气管吸出物及血液标本,用RT-PCR和Real-ti me PCR方法检测流感病毒A/M、A/H5N1、A/H7N7、A/H9N1亚型特异性核苷酸片段;气管吸出物接种SPF鸡胚进行病毒分离,并对分离物进行鉴定和序列测定及分析;利用血凝抑制试验检测血清标本抗体。结果表明病人气管吸出物可以检测到甲型流感病毒M片段及H5亚型的特异性HA基因。2005年11月9日采集的血清标本用Real-ti me PCR检测到甲型流感病毒M基因。从病人的气管吸出物中分离到H5N1病毒(A/Anhui/1/2005),对病毒的HA基因序列结果进行分析表明病毒是禽源的,其主要依据是受体结合位点第226~228位氨基酸位点(QSG)为禽流感病毒所特异,HA受体连接肽仍为9个碱性氨基酸(LRERRRKRP);基因进化树分析显示,HA基因与禽源病毒进化距离接近。发病后7、8、9d的血清H5N1禽流感病毒HI抗体小于20。对该病例的病原学研究证明,该病例为H5N1禽流感感染病例。  相似文献   

16.
We mapped the hemagglutinin (HA) antigenic epitopes of a highly pathogenic H5N1 influenza virus on the three-dimensional HA structure by characterizing escape mutants of a recombinant virus containing A/Vietnam/1203/04 (H5N1) ΔHA and neuraminidase genes in the genetic background of A/Puerto Rico/8/34 (H1N1) virus. The mutants were selected with a panel of eight anti-HA monoclonal antibodies (MAbs), seven to A/Vietnam/1203/04 (H5N1) virus and one to A/Chicken/Pennsylvania/8125/83 (H5N2) virus, and the mutants’ HA genes were sequenced. The amino acid changes suggested three MAb groups: four MAbs reacted with the complex epitope comprising parts of the antigenic site B of H3 HA and site Sa of H1 HA, two MAbs reacted with the epitope corresponding to the antigenic site A in H3 HA, and two MAbs displayed unusual behavior: each recognized amino acid changes at two widely separate antigenic sites. Five changes were detected in amino acid residues not previously reported as changed in H5 escape mutants, and four others had substitutions not previously described. The HA antigenic structure differs substantially between A/Vietnam/1203/04 (H5N1) virus and the low-pathogenic A/Mallard/Pennsylvania/10218/84 (H5N2) virus we previously characterized (N. V. Kaverin et al., J. Gen. Virol. 83:2497-2505, 2002). The hemagglutination inhibition reactions of the MAbs with recent highly pathogenic H5N1 viruses were consistent with the antigenic-site amino acid changes but not with clades and subclades based on H5 phylogenetic analysis. These results provide information on the recognition sites of the MAbs widely used to study H5N1 viruses and demonstrate the involvement of the HA antigenic sites in the evolution of highly pathogenic H5N1 viruses, findings that can be critical for characterizing pathogenesis and vaccine design.  相似文献   

17.
During the latter half of 2005 a widespread outbreak caused by influenza highly pathogenic H5N1 virus among wild and domestic birds occurred in Russia. As pathogenicity level is a polygenic feature and majority of individual genes of influenza A viruses contribute to pathogenicity of influenza viruses to birds, animals and humans. Nucleotide sequencing of the entire genome of influenza H5N1 virus isolates obtained in Kurgan region (Western Siberia) was performed. Structure of viral proteins was analyzed according to the predicted amino acid sequences. HA receptor-binding site of A/chicken/Kurgan/05/2005 and A/duck/Kurgan/08/2005 strains was typical for avian influenza viruses and contained Glu and Gly at positions 226 and 228, respectively. Structure of the cluster of positively charged amino acid residues at the cleavage site was identical for all isolates: QGERRRKKR. According to the data of neuraminidase structure analysis NA of the H5N1 isolates tested was suggested to belong to Z genotype. Amino acid residues typical for birds were revealed in 30 out of 32 positions of M1, M2, NP, PA and PB2 proteins determining host range specificity. One strain isolated in Kurgan contained lysine in position 627 of PB2 protein. Kurgan isolates was shown to have remantadine-sensitive genotype. Glutamic acid was found at position 92 of NS1 protein in both strains indicating virus resistance to interferon. Phylogenetic analyses allowed relating Kurgan isolates to subclade II of clade II of highly pathogenic H5N1 influenza viruses.  相似文献   

18.
To study genetic evolution of Moroccan influenza A(H1N1)pdm09 virus strains, we conducted a molecular characterization of the hemagglutinin gene subunit 1 (HA1) of 36 influenza A(H1N1)pdm09 virus strains. The stains were collected from patients in Rabat and Casablanca during two influenza seasons 2009–2010 and 2010–2011. Nucleotide and amino acid sequences of 14 influenza A(H1N1)pdm09 virus strains from 2009 to 2010 were ~97 and 99 %, respectively, similar to the reference strain A/California/07/2009 (H1N1). Phylogenetic analysis of 22 influenza A(H1N1)pdm09 virus strains from 2010 to 2011 revealed a co-circulation of three well-described different genetic groups. Most important, none of the identified groups showed significant changes at the antigenic site of the virus HA1 subunit which may alter the efficacy of California/07/2009 (H1N1) vaccine.  相似文献   

19.
雍玮  乔梦凯  石利民  王璇  何敏  丁洁 《微生物学通报》2019,46(11):3058-3069
【背景】H5N1禽流感病毒可以感染人类导致重症呼吸道感染,致死率高。【目的】研究我中心确认的一例人感染高致病性禽流感H5N1病毒A/Nanjing/1/2015的可能起源及基因组分子特征。【方法】对病人痰液样本中的H5N1病毒进行全基因组测序,使用CLC Genomics Workbench 9.0对序列进行拼接,使用BLAST和MEGA 5.22软件进行同源性比对和各片段分子特征分析。【结果】该株禽流感病毒属于H5亚型的2.3.2.1c家系,其8个片段均与江浙地区禽类中分离的病毒高度同源,未发现有明显的重配。分子特征显示,该病毒血凝素(Hemagglutinin,HA)蛋白裂解位点为PQRERRRR/G,受体结合位点呈现禽类受体特点,但出现D94N、S133A和T188I氨基酸置换增强了病毒对人类受体的亲和性。神经氨酸酶(Neuraminidase,NA)蛋白颈部在49-68位缺失20个氨基酸,非结构蛋白1 (Non-structure protein,NS1)存在P42S置换和80-84位氨基酸的缺失。其他蛋白中也存在多个增强病毒致病力和对人类细胞亲和力的氨基酸突变。对耐药位点分析发现存在对奥司他韦的耐药突变H_274Y,病毒对金刚烷胺仍旧敏感。【结论】人感染高致病性禽流感H5N1病毒A/Nanjing/1/2015属于2.3.2.1c家系,禽类来源,关键位点较保守,但仍出现了多个氨基酸的进化与变异使其更利于感染人类。H5N1禽流感病毒进化活跃,持续动态监测不能放松。  相似文献   

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