[Comparative study of the replication difference of HearNPV in infected exponential and stationary host cells]

Real-time quantitative PCR was used to characterize HearNPV DNA replication in exponential and stationary phases of HzAM1 cells. Results showed that the doubling time of HzAM1 cells was 22 h in exponential phases. Most of the exponential cells were in S phase (48.6%), and most of the stationary cells in G2/M phase (72.6%). The replication of viral DNA was completed within 60 h post infection (h p. i.) in different phases of HzAM1 cells. During 14 to 20 h p. i., the doubling time of HearNPV replica-tion was 1.8 h in exponential cells and 1.9 h in stationary cells, and no significant difference was found between them. But the amounts of BV entering and releasing, the final progeny virions and viral protein products in the infected exponential phase cells were obviously higher than that in the stationary phase cells. 25% of the total synthesized viral DNAs were released from infected exponential phase cells, but on-ly 13% from the infected stationary phase cells. Viral DNA started to be replicated from 7-8 h p. i. both in infected exponential phase and in stationary phase cells. But in infected exponential phase cells, BVs were started to release from 18-20 h p. i., and BVs were started to release from 22-25 h p. i. from infected sta-tionary phase cells. During 30-60 h p. i., the BV releasing rate was about 483 copies/cell/h in the expo-nential phase cells, but was 100 copies/cell/h in the stationary-phase cells. The initial viral DNA entering into exponential phase cells was much more than that entered into the stationary phase cells. The data of cell membrane fluidity at exponential and stationary phases suggested that the fluidity of cell membrane played an important role during virus entry.