Introduction: The PA-I38T substitution strongly reduced PA susceptibility to BXA.
Method: PA I38T mutation in pMP-PA-Gi /-Vic and absence of PCR introduced errors in purified plasmid DNA was confirmed by sequencing using gene-specific primers and vector-specific primers (Supplementary Table 2).
Method: Briefly, the complete set of eight vectors encoding the vRNA of wild type and variant rgA/Victoria/3/75 (rgH3N2-WT, rgH3N2-PA-I38T) and rgA/Giessen/6/2009 (rgH1N1-WT, rgH1N1-PA-I38T) were co-transfected into a co-culture of 293T/MDCK-II cells.
Method: Relevant primer pairs (Supplementary Table 1) were used for site-directed m
Host Adaptive Evolution of Avian-Origin H3N2 Canine Influenza Virus.
Result: For the NA protein, a T16A substitution occurs at a site located in the transmembrane region of this protein (Figure 4).
Result: Given the role of the NS1 protein in suppressing host cellular immune responses, the NS1-E227K mutation might be a molecular determinant to hone the function of the immune suppression by H3N2 CIV.
Result: However, it is interesting to note that 11 out of the 54 (20.37%) effective substitutions in H3N2 CIV, including HA-G146S, HA-V242I, HA-V418I, M1-V15I, M2-
Novel Clade 2.3.4.4b Highly Pathogenic Avian Influenza A H5N8 and H5N5 Viruses in Denmark, 2020.
Abstract: Genetic analyses of one of the H5N8 viruses revealed the presence of a substitution (PB2-M64T) that is highly conserved in human seasonal influenza A viruses.
Result: In addition, one of the H5N8 viruses (A/barnacle goose/Denmark/14139-3/2020) had a PB2-M64T amino acid substitution that is highly conserved in human influenza A H1N1, H2N2, and H3N2 viruses.
Result: The PB2-M64T substitution was not present in A/Astrakhan/3212/2020(H5N8) (EPI_ISL_1038924) virus detected in workers at a poultry farm in Russia on 12 December 2020.
Discussion: The genetic characterization revealed that one of the Danish H5N8 viruses contained a PB2-M64T substitution.
Dual R108K and G189D Mutations in the NS1 Protein of A/H1N1 Influenza Virus Counteract Host Innate Immune Responses.
Abstract: The 2018 virus harbored amino acid mutations (I123V and N205S) in important functional sites; however, 108R and 189G were highly conserved between A/California/07/2009 and the 2018 variant.
Abstract: To better understand interactions between influenza viruses and the human innate immune system, we generated and rescued seasonal 2009 H1N1 IAV mutants expressing an NS1 protein harboring a dual mutation (R108K/G189D) at these conserved residues and then analyzed its biological characteristics.
Introduction: Here, we sequenced a seasonal 2009 H1N1 influenza virus isolated in 2018 and confirmed the presence of mutations I123V and N205S in important functional sites.
Introduction: However, the NS
Molecular Characterization of Seasonal Influenza A and B from Hospitalized Patients in Thailand in 2018-2019.
Discussion: Among these additional substitutions, the V303I amino acid substitution has been reported in the A/H3N2 viruses with a low resistance to neuraminidase inhibitors.
Discussion: For H3N2 viruses, we did not detect the mutations conferring resistance to neuraminidase inhibitors such as E119V, D151E, I222V, R224K, E276D, N249S, R292K, and R371K in the NA gene segment of our H3N2 isolates.
Discussion: However, an additional mutation (S200P) was detected in the Thai A/H1N1 isolates.
Discussion: Our Flu B isolates
Identification of H3N2 NA and PB1-F2 genetic variants and their association with disease symptoms during the 2014-15 influenza season.
Abstract: In human nasal epithelial cell cultures, a virus with the novel NAg+F2P genotype replicated less well compared with a virus with the parental genotype.
Abstract: Retrospective analyses of clinical data showed that NAg+F2P genotype viruses were associated with increased cough and shortness of breath in infected patients.
Abstract: The NA and PB1-F2 mutations were present in a subset of clade 3C.2a viruses (NAg+F2P), which dominated during the subsequent influenza seasons.
Abstract: The isolates were classified by HA clade and the presence of a new set of co-selected mutations in NA (a glycosylation site, NAg+) and PB1-F2 (H75P).
Method: A/Colu
Dynamic residue interaction network analysis of the oseltamivir binding site of N1 neuraminidase and its H274Y mutation site conferring drug resistance in influenza A virus.
Discussion: 6 and 7 show that in the WT NA, the 150-loop region undergoes conformational changes with large fluctuations between the open and closed states, whereas in the H274Y mutant NA, the 150-loop remains open.
Discussion: After the H274Y mutation, however, the structural fluctuation of the 150-loop became much smaller.
Discussion: As already mentioned, the 150 loop of NA is reported to open after the H274Y mutation ().
Discussion: Figure 6 shows the conformational changes of the 150-loop region (residues 147-152) in the WT and H274Y mutant NA by superimposing 100 snapshot images obtained from the MD simulations.
Discussion: Figure 7 shows the structural fluctuations of each residu
Genetic characterisation of the influenza viruses circulating in Bulgaria during the 2019-2020 winter season.
Abstract: The HA genes of A(H3N2) viruses analysed belonged to clades 3C.3a (21 strains) and 3C.2a (5 strains): subclades 3C.2a1b + T131K, 3C.2a1b + T135K-B and 3C.2a1b + T135K-A.
Risk of Environmental Exposure to H7N9 Influenza Virus via Airborne and Surface Routes in a Live Poultry Market in Hebei, China.
PMID: 34164347
2021
Frontiers in cellular and infection microbiology
Abstract: More importantly, after 5 passages in mice, the virus acquired two adaptive mutations, PB1-H115Q and B2-E627K, exhibiting increased virulence and aerosol transmissibility.
Introduction: reported that mutations in PB2 (E627K), NA (R294K) and PA (V100A) were significantly correlated with increased mortality, while other mutations in HA (N276D) and PB2 (N559T) were distinctly correlated with mild cases.
Discussion: Based on our data, we found that H115Q in PMID: 34337007
2021
BioMed research international
Abstract: Our study suggested that the adaptation changes for the viral fitness to survive in a new host species (MDCK cells) might involve many genes, for example, the amino acid substitution 177G or 177W adjacent to the receptor-binding residues in the HA1 globular head and the substitution M315I in PB2.
Result: On the other hand, both the autopsy specimens and the virus isolates contained the S31N substitution in the M2 protein, indicating the amantadine and rimantadine resistance.
Result: The H274Y substitution, which indicated the oseltamivir and peramivir resistance, was not present in both the autopsy specimens and the virus isolates, even though the patient received a full course of oseltamivir treatment before his death.
IV mutation literature information.
PMID: 
2021
Frontiers in microbiology
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