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美國研究人員日前在最新一期《BMC 微生物學雜志》上發表研究報告說，經過與以往造成流感大流行的致命流感病毒進行對比，他們認為目前在全球蔓延的甲型H1N1流感病毒并不像人們擔心的那么嚴重。 人類曾經歷過幾次流感大流行。美國利弗莫爾勞倫斯國家實驗所的喬納森·艾倫和湯姆·斯萊扎克從被保留下來的、造成以往幾次流感大流行的病毒毒株中鑒別出34種基因標記物，這些標記物與病毒宿主特異性和高致死率有關，影響著流感的嚴重程度；與此同時，他們從甲型H1N1流感病毒毒株樣本中鑒別出17種影響流感嚴重程度的基因標記物。在對這些基因標記物進行對比后發現，甲型H1N1流感病毒樣本中的基因標記物與致命流感病毒中的基因標記物沒有相似性。 研究人員認為，這表明甲型H1N1流感病毒缺少以往出現的致命流感病毒所具有的特性。但他們也同時強調說，這一研究結果并不表示目前的甲型H1N1流感不嚴重，而且，對此作出定論還有待進一步研究。 生物谷推薦原始出處： BMC Microbiology 2009, 9:77doi:10.1186/1471-2180-9-77 Conserved amino acid markers from past influenza pandemic strains Jonathan E Allen , Shea N Gardner , Elizabeth A Vitalis and Tom R Slezak Abstract (provisional) Background Finding the amino acid mutations that affect the severity of influenza infections remains an open and challenging problem. Of special interest is better understanding how current circulating influenza strains could evolve into a new pandemic strain. Influenza proteomes from distinct viral phenotype classes were searched for class specific amino acid mutations conserved in past pandemics, using reverse engineered linear classifiers. Results Thirty-four amino acid markers associated with host specificity and high mortality rate were found. Some markers had little impact on distinguishing the functional classes by themselves, however in combination with other mutations they improved class prediction. Pairwise combinations of influenza genomes were checked for reassortment and mutation events needed to acquire the pandemic conserved markers. Evolutionary pathways involving H1N1 human and swine strains mixed with avian strains show the potential to acquire the pandemic markers with a double reassortment and one or two amino acid mutations. Conclusion The small mutation combinations found at multiple protein positions associated with viral phenotype indicate that surveillance tools could monitor genetic variation beyond single point mutations to track influenza strains. Finding that certain strain combinations have the potential to acquire pandemic conserved markers through a limited number of reassortment and mutation events illustrates the potential for reassortment and mutation events to lead to new circulating influenza strains. (責任編輯：Doctor001) |
