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ObjectiveTo determine the genomic characteristics of a subgenus B human adenovirus strain isolated in Shanghai in 2021. MethodsAn adenovirus type 55 strain was isolated and identified from a patient with acute hemorrhagic conjunctivitis （AHC）. Complete genome of the strain was obtained using the next-generation sequencing （NGS）. Phylogenetic trees were reconstructed based on the sequences of Hexon， Fiber， Penton and complete genome to genomically characterize this strain. ResultsPhylogenetic analysis based on the complete genome classified this strain （MH2021001） into subgenus B， subspecies B2 of HAdV-55. Hexon gene of MH2021001 had close phylogenetic relationship with HAdV-11， while Fiber and Penton genes had close relationship with HAdV-14. The MH2021001 showed high nucleotide identity with currently prevalent HAdV⁃55 strains （>99.90%）. The complete genome had 99.96% nucleotide identity to the 73-GD_CHN_2016 strain isolated in Guangdong. In addition， the amino acid sequence of MH2021001 had several substitutions in regions coding for E1B， L4， E3 and L5. ConclusionThis strain has been classified to HAdV-B55. No recombination event is identified in the complete genome. Due to multiple amino acid substitutions， the biological characteristics of the strain need to be further identified.
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Objective To study whether the human bone marrow mesenchymal stem cells (HBMSCs) can repair damaged neural cells induced by okadaic acid (OA).Methods Neuroblastoma cell line SH-SY5Y cells were used to incubate with 20nmol/L okadaic acid for 24h,establishing Alzheimer's Disease cell model;Three groups were set up:normal group,okadaic acid-damaged (OA-damaged) group,hBMSCs-treatment group.The cells were injured for 24h with 20nmol/L OA in OA-damaged group,and treated with conditioned medium obtaining hBMSCs for 24h after 24h OA injury in the treatment group.Then CCK-8 was used for detecting cell vitality,immune fluorescence dyed microtubules and micro filaments for determining the dendritic cell length and fluorescence intensity,in addition,Western blotting for analyzing the protein level of phosphorylated tau and total tau proteins.Results Okadaic acid damaged SH-SY5Y cells,contributed to shrinkage,collapse,cavitation of the SH-SY5Y cell body,dendritic shortening and fracture,and irregular arrangement of microtubule microfilaments;while BMSCs conditioned medium made SHSYSY cell body become round and longer,dendrites restored,and microtubules and microfilaments arranged regularly,fluorescence intensity enhanced.Meanwhile,it also down-regulated the level of OA-induced tau phosphorylation.Conclusion hBMSCs have repair effects on the neural cell damage induced by okadaic acid.