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Avian influenza A viruses could get across the species barrier and be fatal to humans. Highly pathogenic avian influenza H5N1 virus was an example. The mechanism of interspecies transmission is not clear as yet. In this research, the protein sequences of 237 influenza A viruses with different subtypes were transformed into pseudo-signals. The energy features were extracted by the method of wavelet packet decomposition and used for virus classification by the method of hierarchical clustering. The clustering results showed that five patterns existed in avian influenza A viruses, which associated with the phenotype of interspecies transmission, and that avian viruses with patterns C and E could across species barrier and those with patterns A, B and D might not have the abilities. The results could be used to construct an early warning system to predict the transmissibility of avian influenza A viruses to humans. 相似文献
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The influenza A viral heterotrimeric polymerase complex (PA, PB1, PB2) is known to be involved in many aspects of viral replication and to interact with host factors, thereby having a role in host specificity. The polymerase protein sequences from the 1918 human influenza virus differ from avian consensus sequences at only a small number of amino acids, consistent with the hypothesis that they were derived from an avian source shortly before the pandemic. However, when compared to avian sequences, the nucleotide sequences of the 1918 polymerase genes have more synonymous differences than expected, suggesting evolutionary distance from known avian strains. Here we present sequence and phylogenetic analyses of the complete genome of the 1918 influenza virus, and propose that the 1918 virus was not a reassortant virus (like those of the 1957 and 1968 pandemics), but more likely an entirely avian-like virus that adapted to humans. These data support prior phylogenetic studies suggesting that the 1918 virus was derived from an avian source. A total of ten amino acid changes in the polymerase proteins consistently differentiate the 1918 and subsequent human influenza virus sequences from avian virus sequences. Notably, a number of the same changes have been found in recently circulating, highly pathogenic H5N1 viruses that have caused illness and death in humans and are feared to be the precursors of a new influenza pandemic. The sequence changes identified here may be important in the adaptation of influenza viruses to humans. 相似文献
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禽流感及人感染高致病性禽流感的危害和防治措施 总被引:5,自引:0,他引:5
王志强 《科技情报开发与经济》2006,16(13):119-120
阐述了禽流感病毒的特点及其流行病学特征,着重介绍了人感染高致病性禽流感的致病机制、治疗措施和预防的方法。 相似文献
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家禽胚胎干细胞的研究进展 总被引:1,自引:0,他引:1
王丙云 《佛山科学技术学院学报(自然科学版)》2002,20(4):67-70
阐述了干细胞及胚胎干细胞的概念,它的发展历程,着重讨论了家禽胚胎发育的特点以及家禽胚胎干细胞的分离与体外培养方法及应用前景,将来的发展方向。 相似文献
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2011年春季采用样线法对贵州草海自然保护区的鸟类进行调查,按照生境特征分为农田、蔬菜地、草甸、水域、树林5个鸟类群落,共记录到鸟类89种,隶属15目34科.其中,树林鸟类群落的密度(MD)最高(13.81只·hm-2),草甸鸟类群落的现存生物量(EB)最高(25 057 g·hm-2),水域生境中的物种数(47种)、... 相似文献