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Objective:To analyze the variation and evolution characteristics of hemagglutinin (HA) and neuraminidase (NA) genes of influenza B virus circulating in Jining from 2017 to 2020.Methods:Throat swab specimens were collected from patients with influenza-like symptoms in sentinel hospitals and influenza outbreaks in Jining from 2017 to 2020 and tested for influenza B virus nucleic acid. After virus isolation, 20 representative strains of influenza B virus were selected to sequence the full length of HA and NA genes. Phylogenetic trees were constructed and the molecular characteristics were analyzed using bioinformatics software. Results:A total of 4 575 specimens were collected and 842 of them were positive for influenza virus, including 398 (8.7%, 398/4 575) influenza B virus-positive specimens. The positive rate of influenza B virus was 47.27% (398/842). The isolated influenza B virus strains of Victoria (BV) and Yamagata (BY) lineages from 2017 to 2020 shared 98.7%-98.8% and 98.5%-99.1% homology in HA gene with vaccine strains, respectively. The BV lineage strains isolated from 2018 to 2020 belonged to Victoria clade 1A branch and the BY lineage strains isolated from 2017 to 2018 belonged to Yamagata clade 3 branch. Mutations were detected in several antigenic sites, but not in the sites related to NA inhibitor resistance. Conclusions:Mutations in several antigenic sites caused antigenic changes in influenza B virus of BV and BY lineages, which might be related to the outbreaks of influenza B virus infection in Jining during 2017 to 2020.
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Objective@#To understand the epidemiological characteristics of outbreaks and analyze the genetic characteristics of the whole genome of influenza H3N2 virus among avian-human-swine, and to elaborate the source of influenza virus.@*Methods@#The epidemic information was collected using the case investigation, the pharyngeal swab samples from influenza-like-illness cases were detected by real-time PCR and virus isolation. The phylogeny and molecular features of whole-genome were analyzed with EditSeq and MEGA 5.05 software.@*Results@#The prevalence rate of this outbreak was 34.88%, 15 samples of throat swabs were collected, the positive rate of nucleic acid detection was 73.33%, 5 strains of seasonal influenza A (H3N2) influenza viruses were isolated. The phylogenetic analysis showed the eight gene segments of the isolated influenza viruses belonged to the same cluster with 2015-2016 influenza vaccine strain A/Switzerland/9715293/2013(H3N2), and no recombination was found. Compared with vaccine strain, 14 variant amino acids of protein of HA were identified, and 8 of them were located in antigenic sites. All strains were sensitive to neuraminidase inhibitors while they showed resistance to blockers of M2 ion channel. The glycosylation sites analysis showed that two new glycosylation sites NRT151-153 and NAT245-247were added.@*Conclusions@#The outbreak was caused by seasonal influenza A (H3N2) virus which had an antigenic drift and no genetic avian-human-swine recombination was found.
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Objective@#To study the interaction between hepatitis B virus X protein(HBx) and mitochondrial elongation factor G1 (EFG1) in yeast cells or hepatoma cells.@*Methods@#After verification the interaction between HBx and EFG1 by CytoTrap yeast two-hybrid system, EFG1 genome was amplified by means of polymerase chain reaction(PCR) and cloned into the pcDNA3.1/myc-His(-)A vector, following verification by sequencing. Expression of HBx and EFG1 protein was verified in Huh7 cells. Then the recombinant vector pcDNA3.1/myc-His(-)A-EFG1 and pFLAG-CMV-2-HBx were transfected into Huh7 cells; 48 h later, the cells were lysed. The direct interaction between HBx and EFG1 was further confirmed by the Co-immunoprecipitation (Co-IP) assay.@*Results@#The interaction between HBx and EFG1 was successfully verified by CytoTrap yeast two-hybrid system. The recombined plasmid pcDNA3.1/myc-His(-)A-EFG1 was obtained. Furthermore, Co-IP assay was used to confirm the interaction between HBx and EFG1 in Huh7 cells.@*Conclusions@#The direct interaction between HBx and EFG1 was confirmed. Therefore our findings provide experimental basis for the influence of HBx protein on the expression of mitochondrial protein and provide new insights into the pathogenesis of HBx in the development of hepatocellular carcinoma.