RESUMO
Apart from natural reassortment, co-circulation of different avian influenza virus strains in poultry populations can lead to generation of novel variants and reassortant viruses. In this report, we studied the genetics and functions of a reassorted non-structural gene (NS) of H9N2 influenza virus collected from back yard poultry (BYP) flock. Phylogenetic reconstruction based on hemagglutinin and neuraminidase genes indicates that an isolate from BYP belongs to H9N2. However, the NS gene-segment of this isolate cluster into genotype Z, clade 2.2 of the highly pathogenic H5N1. The NS gene plays essential roles in the host-adaptation, cell-tropism, and virulence of influenza viruses. However, such interpretations have not been investigated in naturally recombinant H9N2 viruses. Therefore, we compared the NS1 protein of H9N2 (H9N2/NS1) and highly pathogenic H5N1 (H5N1/NS1) in parallel for their abilities to regulate different signaling pathways, and investigated the molecular mechanisms of IFN-ß production in human, avian, and mink lung cells. We found that H9N2/NS1 and H5N1/NS1 are comparably similar in inhibiting TNF-α induced nuclear factor κB and double stranded RNA induced activator protein 1 and interferon regulatory factor 3 transcription factors. Thus, the production of IFN-ß was inhibited equally by both NS1s as demonstrated by IFN stimulatory response element and IFN-ß promoter activation. Moreover, both NS1s predominantly localized in the nucleus when transfected to human A549 cells. This study therefore suggests the possible increased virulence of natural reassortant viruses for their efficient invasion of host immune responses, and proposes that these should not be overlooked for their epizootic and zoonotic potential.
Assuntos
Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/isolamento & purificação , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Animais , Linhagem Celular , Núcleo Celular/química , Interações Hospedeiro-Patógeno , Humanos , Tolerância Imunológica , Virus da Influenza A Subtipo H5N1/genética , Interferon beta/antagonistas & inibidores , Vison , Paquistão , Filogenia , Aves Domésticas/virologia , Análise de Sequência de DNARESUMO
A new species of lizard of the genus Liolaemus from Neuquén Province, western Argentina, is described. The new species is a member of the Liolaemus rothi species complex, and mitochondrial and nuclear molecular data show it as sister taxon of the clade composed of (L. hermannunezi (L. tromen + L. loboi)), differing in size, squamation, coloration, and sexual dimorphism from the other species of this group. Liolaemus sitesi sp. nov. has a dark body coloration with series of notched blotches on the dorsum, with bright spots, and a very iridescent yellow-green coloration in natural light. Liolaemus sitesi sp. nov. is found only in the Auca Mahuida volcano and is terrestrial, dwelling on the stony slopes with sandy soil between 1300 m and the volcano summit.
Assuntos
Lagartos/classificação , Lagartos/genética , Animais , Argentina , Núcleo Celular/genética , Citocromos b/genética , Feminino , Lagartos/anatomia & histologia , Masculino , Proteínas Mitocondriais/genética , Filogenia , Reação em Cadeia da Polimerase , RNA/genética , RNA Mitocondrial , RNA Ribossômico/genéticaRESUMO
In 2009, a novel H1N1 influenza (pH1N1) virus caused the first influenza pandemic in 40 y. The virus was identified as a triple reassortant between avian, swine, and human influenza viruses, highlighting the importance of reassortment in the generation of viruses with pandemic potential. Previously, we showed that a reassortant virus composed of wild-type avian H9N2 surface genes in a seasonal human H3N2 backbone could gain efficient respiratory droplet transmission in the ferret model. Here we determine the ability of the H9N2 surface genes in the context of the internal genes of a pH1N1 virus to efficiently transmit via respiratory droplets in ferrets. We generated reassorted viruses carrying the HA gene alone or in combination with the NA gene of a prototypical H9N2 virus in the background of a pH1N1 virus. Four reassortant viruses were generated, with three of them showing efficient respiratory droplet transmission. Differences in replication efficiency were observed for these viruses; however, the results clearly indicate that H9N2 avian influenza viruses and pH1N1 viruses, both of which have occasionally infected pigs, have the potential to reassort and generate novel viruses with respiratory transmission potential in mammals.
Assuntos
Hemaglutininas Virais/metabolismo , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H9N2/genética , Neuraminidase/metabolismo , Infecções por Orthomyxoviridae/transmissão , Vírus Reordenados/genética , Proteínas Virais/metabolismo , Animais , Linhagem Celular , Cães , Ensaio de Imunoadsorção Enzimática , Furões , Hemaglutininas Virais/genética , Imuno-Histoquímica , Neuraminidase/genética , Infecções por Orthomyxoviridae/genética , Proteínas Virais/genéticaRESUMO
On June 11, 2009 the World Health Organization (WHO) declared a new H1N1 influenza pandemic. This pandemic strain is as transmissible as seasonal H1N1 and H3N2 influenza A viruses. Major concerns facing this pandemic are whether the new virus will replace, co-circulate and/or reassort with seasonal H1N1 and/or H3N2 human strains. Using the ferret model, we investigated which of these three possibilities were most likely favored. Our studies showed that the current pandemic virus is more transmissible than, and has a biological advantage over, prototypical seasonal H1 or H3 strains.
