China ; epidemiology ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Humans ; Influenza B virus ; genetics ; Influenza, Human ; epidemiology ; genetics

In Taiwan, the first human-infecting H6N1 avian influenza virus was isolated in 2013. To better understand the origin, evolutionary relationship and pathogenesis of the H6N1 virus, we studied the adaptive evolution and evolutionary dynamics of the hemagglutinin (HA) genes of the H6N1 virus in Taiwan. We felt that such studies woud contribute to the further study and control of the virus. Datasets were gained from the Flu and Global Initiative on Sharing All Influenza Data (GISAID) databases. Then, phylogenetic trees and evolutionary dynamics were reconstructed. The evolutionary rate and characterization of adaptive evolution were analyzed by bioinformatic methods. Results indicated that the HA genes of H6N1 in Taiwan were divided into at least five types, and that the new types that the infected human H6N1 belonged to could be local advantage type at present. Evolutionary dynamics revealed the viral population expanded first at the end of 1971, reduced sharply in 2008, and then increased slightly. Three sites were identified under positive selection, suggesting that various sites might increase the adaptive ability of the virus. Eighty-nine sites were under negative selection, revealing that these sites might play an important role in the replication and epidemiology of the virus. Interestingly, site 329 upstream from the cleavage site was also under negative selection, suggesting that this site might be associated with the virulence of H6N1. These data suggest that the HA genes of the Taiwanese H6N1 virus have been undergoing adaptive evolution, and that an outbreak may occur again. Hence, more attention should be paid to the identified sites, to enable timely monitoring and control of a future epidemic.
Animals ; Birds ; Evolution, Molecular ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Influenza A virus ; genetics ; Influenza in Birds ; virology ; Taiwan

The expression of the hemagglutinins of Avian influenza virus H5 H7and H9 subtypes was studied in this article by Pichia pastoris, one of the eukaryotis expression systems. Three reconstructed expression plasmids and engineering strains, named pPIC9K-H5HA, pPIC9K-H7HA, pPIC9K-H9HA and GS115/pPIC9K-H5HA, GS115/pPIC9K-H7HA, GS115/pPIC9K-H9HA repectively, were obtained. The reconstructed yeast engineering strains were identified by MD and MM plate selecting and PCR. The induced interests proteins were examined by SDS-PAGE and Western-bloting,the results showed that the interest genes were expressed exactly. And this will be helpful in the future study of antigen detection and antibody detection kit, as well in the subunit vaccines developing.
Animals ; Hemagglutinin Glycoproteins, Influenza Virus ; biosynthesis ; genetics ; Influenza A Virus, H5N1 Subtype ; genetics ; Influenza A Virus, H7N7 Subtype ; genetics ; Influenza A Virus, H9N2 Subtype ; genetics ; Pichia ; genetics ; metabolism

Evolution, Molecular ; Humans ; Influenza A virus ; genetics ; Influenza, Human ; epidemiology

To understand the genetic characteristics of hemagglutinin (HA) and neuraminidase (NA) of type B influenza viruses in Guangzhou in 2006, three virus strains from etiology surveillance and seven strains from outbreaks were investigated. Genome RNAs of type B influenza viruses were extracted and reverse-transcripted into cDNAs using random primers. The whole-length DNA of HA and NA were amplified by polymerase chain reaction (PCR), cloned into T-A plasmid and sequenced, and analyzed phylogenetically by DNAstar software. The results showed that the HA of type B influenza viruses were similar and the homology were more than 99%. The type B influenza viruses belong to Victoria lineage. The NA of the type B influenza viruses were similar and the homology were more than 98%. Phylogenetic trees of HA and NA showed that the isolates from etiology surveillance formed a cluster, and the isolates from outbreaks were separated from the cluster. The homology of the type B influenza viruses with B/Shanghai/361/2002, which is the WHO recommended influenza vaccine strain in 2005-2006, were 88.9%-89.7%. It suggested the protective effect of influenza vaccine against type B influenza viruses used in 2005-2006 in Guangzhou may not be afforded.
China ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Influenza B virus ; genetics ; Neuraminidase ; genetics ; Phylogeny ; Time Factors

OBJECTIVETo determine if global warming has an impact on the evolution of hemagglutinins from influenza A viruses, because both global warming and influenza pandemics/epidemics threaten the world.

METHODS4 706 hemagglutinins from influenza A viruses sampled from 1956 to 2009 were converted to a time-series to show their evolutionary process and compared with the global, northern hemisphere and southern hemisphere temperatures, to determine if their trends run in similar or opposite directions. Point-to-point comparisons between temperature and quantified hemagglutinins were performed for all species and for the major prevailing species.

RESULTSThe comparisons show that the trends for both hemagglutinin evolution and temperature change run in a similar direction.

CONCLUSIONGlobal warming has a consistent and progressive impact on the hemagglutinin evolution of influenza A viruses.

To understand the evolutionary characterization of HA1 of H1N1 influenza virus HA gene circulaing from 1981 to 2005 in China, viral RNAs of 370 H1N1 strains were extracted and transcribed into cDNA by reverse transcriptase and amplified by PCR. The products of PCR were sequenced. The sequences were analyzed through biometic software. The results showed that all the four antigenic sites were mutated, bigger change occurred on the Sb and Ca sites; the 130 loop of receptor binding sites(RBS) of HA1 amino acid deleted at the 134th site in 1991 firstly, then the number of the deleted strains were increasing, since 2000, all the strains had deleted at the 134th site, and simultaneously, the amino acid at 137th site was substituted by S for T. The change of HA1 glycosylation sites was found and 7 sites kept stable from 2000 to 2005. The H1N1 strains of the same year almost clustered in the same group on the phylogenetic tree and were irrelevant to virus isolated time and area. There appeared two groups of 2005 H1N1 virus strains that differed in time of virus isolation.
China ; Genes, Viral ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Influenza A Virus, H1N1 Subtype ; genetics ; Phylogeny ; Time Factors

Objective: To analyze the genetic characteristics of the first human infection with the G4 genotype of Eurasian avian H1N1 swine influenza virus (EA H1N1 SIV) in Shaanxi Province. Methods: The patient's throat swab samples were collected, and MDCK cells were inoculated for virus isolation to obtain the virus strain. The whole genome deep sequencing method was used to obtain the eight gene segments of the isolated strain. The nucleotide homology analysis was conducted through the Blast program in the GenBank database, and a phylogenetic tree was constructed to analyze the genetic characteristics of the virus. Results: The throat swab specimens of the case were confirmed as EA H1N1 SIV in the laboratory, and the isolated strain was named A/Shaanxi-Weicheng/1351/2022(H1N1v). Homology analysis found that the PB2, NP, HA, NA, and M genes of this isolate had the highest nucleotide homology with A/swing/Beijing/0301/2018 (H1N1), about 98.29%, 98.73%, 97.41%, 97.52%, and 99.08%, respectively. The phylogenetic tree showed that the isolate belonged to G4 genotype EA H1N1 SIV, with PB2, PB1, PA, NP and M genes from pdm/09 H1N1, HA and NA genes from EA H1N1, and NS gene from Triple-reassortant H1N1. The cleavage site of the HA protein was IPSIQSR↓G, which was the molecular characteristic of the low pathogenic influenza virus. No amino acid mutations associated with neuraminidase inhibitors were found in the NA protein. PB2 protein 701N mutation, PA protein P224S mutation, NP protein Q357K mutation, M protein P41A mutation, and NS protein 92D all indicated its enhanced adaptability to mammals. Conclusion: The patient is the first human infection with G4 genotype EA H1N1 SIV in Shaanxi province. The virus is low pathogenic, but its adaptability to mammals is enhanced. Therefore, it is necessary to strengthen the monitoring of such SIVs.
Swine ; Humans ; Animals ; Influenza A Virus, H1N1 Subtype/genetics* ; Phylogeny ; Genotype ; Influenza A virus ; China ; Birds ; Mammals

Objective: To analyze the genetic characteristics of the first human infection with the G4 genotype of Eurasian avian H1N1 swine influenza virus (EA H1N1 SIV) in Shaanxi Province. Methods: The patient's throat swab samples were collected, and MDCK cells were inoculated for virus isolation to obtain the virus strain. The whole genome deep sequencing method was used to obtain the eight gene segments of the isolated strain. The nucleotide homology analysis was conducted through the Blast program in the GenBank database, and a phylogenetic tree was constructed to analyze the genetic characteristics of the virus. Results: The throat swab specimens of the case were confirmed as EA H1N1 SIV in the laboratory, and the isolated strain was named A/Shaanxi-Weicheng/1351/2022(H1N1v). Homology analysis found that the PB2, NP, HA, NA, and M genes of this isolate had the highest nucleotide homology with A/swing/Beijing/0301/2018 (H1N1), about 98.29%, 98.73%, 97.41%, 97.52%, and 99.08%, respectively. The phylogenetic tree showed that the isolate belonged to G4 genotype EA H1N1 SIV, with PB2, PB1, PA, NP and M genes from pdm/09 H1N1, HA and NA genes from EA H1N1, and NS gene from Triple-reassortant H1N1. The cleavage site of the HA protein was IPSIQSR↓G, which was the molecular characteristic of the low pathogenic influenza virus. No amino acid mutations associated with neuraminidase inhibitors were found in the NA protein. PB2 protein 701N mutation, PA protein P224S mutation, NP protein Q357K mutation, M protein P41A mutation, and NS protein 92D all indicated its enhanced adaptability to mammals. Conclusion: The patient is the first human infection with G4 genotype EA H1N1 SIV in Shaanxi province. The virus is low pathogenic, but its adaptability to mammals is enhanced. Therefore, it is necessary to strengthen the monitoring of such SIVs.
Swine ; Humans ; Animals ; Influenza A Virus, H1N1 Subtype/genetics* ; Phylogeny ; Genotype ; Influenza A virus ; China ; Birds ; Mammals

Genes, Viral ; genetics ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; Influenza, Human ; epidemiology ; virology ; Reassortant Viruses ; genetics