| influenza a virus reassortants with surface glycoprotein genes of the avian parent viruses: effects of ha and na gene combinations on virus aggregation. | a series of 33 human-avian and human-mammalian influenza virus reassortant clones possessing either ha or both ha and na genes of the avian or mammalian virus was obtained by crosses of a/ussr/90/77 (h1n1) human virus with 5 avian and 1 mammalian influenza virus strains. all of the reassortants possessing na genes of the h1n1 human parent virus and ha gene of an avian or mammalian parent virus had high values of infectivity/ha activity ratio. since this feature could result from a limited virion ... | 1993 | 8257298 |
| isolation of influenza a viruses from migratory waterfowls in san-in district, western japan in winters of 1980-1982. | in the two winters of 1980-1982, we surveyed migratory waterfowl of some species staying in san-in district, western japan for influenza virus at a few stations. from november 1980 to april 1981, only two strains of influenza virus, h13n1 and h11n6 subtypes, were isolated from 465 fecal samples from pintails but none from 255 samples from whistling swans nor from 625 black-tailed gulls. from november 1981 to march 1982, 17 viruses were isolated from 1156 fecal samples. fourteen viruses, 10 h7n3, ... | 1987 | 3673333 |
| postreassortment changes in a model system: ha-na adjustment in an h3n2 avian-human reassortant influenza virus. | in our previous studies we described the postreassortment changes in the hemagglutinin (ha) of h2n1, h3n1, h4n1 and h13n1 influenza a virus reassortants with has derived from avian viruses and low-functional neuraminidase (na) of a human parent virus a/ussr/90/77 (h1n1). the changes involved amino acid substitutions that increased the negative local charge in the vicinity of the receptor-binding pocket and decreased the affinity of ha to sialic acid receptors. in the present report we describe t ... | 2005 | 15789269 |
| [isolation of influenza virus a (orthomyxoviridae, influenza a virus), dhori virus (orthomyxoviridae, thogotovirus), and newcastle's disease virus (paromyxoviridae, avulavirus) on the malyi zhemchuzhnyi island in the north-western area of the caspian sea]. | the paper presents the results of the 2003 and 2006 environmental virological monitoring surveys on the malyi zhemchuzhnyi island where a large breeding colony of sea gull (laridae) is located. in the past several years, expansion of cormorants (phalacrocorax carbo) has enhanced the intensity of populational interactions. the investigators isolated 13 strains of influenza a virus (orthomyxoviridae, influenza a virus) subtype h13n1 (from sea gulls (n = 4), cormorants (n = 9) 1 strain of dhori vir ... | 2008 | 18590134 |
| using nested rt-pcr analyses to determine the prevalence of avian influenza viruses in passerines in western slovakia, during summer 2007. | the prevalence of avian influenza virus (aiv), together with the distribution of different aiv subtypes, was studied in migratory waterfowl and terrestrial birds caught in western slovakia during summer 2007. both oropharyngeal and cloacal swabs were collected. screening of samples revealed that 18% of oropharyngeal and 18% of cloacal samples were positive for aiv. samples from both the oropharynx and cloaca were positive in only 6.6% of cases. a total of 10 different subtypes of haemagglutinin ... | 2008 | 18777249 |
| [reduction of the functional match of influenza virus hemagglutinin and neuraminidase after reassortation of genes]. | influenza virus a (flua) reassortants with low-functional neuraminidase (na) of subtype n1 and hemagglutinin (ha) of subtypes h2, h3, h4, and h13 display virion aggregation and accumulate to a lower titer because sialyl residues are not completely removed from virion components. nonaggregating variants of flua (h13n1) were shown to result from a mutation that reduces the ha affinity for sialyl substrates. amino acid substitution k156e, which increases a negative charge at the edge of the recepto ... | 2001 | 11443933 |