Chlorella viruses evoke a rapid release of K+ from host cells during the early phase of infection.

Infection of Chlorella NC64A cells by PBCV-1 produces a rapid depolarization of the host probably by incorporation of a viral-encoded K(+) channel (Kcv) into the host membrane. To examine the effect of an elevated conductance, we monitored the virus-stimulated efflux of K(+) from the chlorella cells. The results indicate that all 8 chlorella viruses tested evoked a host specific K(+) efflux with a concomitant decrease in the intracellular K(+). This K(+) efflux is partially reduced by blockers of the Kcv channel. Qualitatively these results support the hypothesis that depolarization and K(+) efflux are at least partially mediated by Kcv. The virus-triggered K(+) efflux occurs in the same time frame as host cell wall degradation and ejection of viral DNA. Therefore, it is reasonable to postulate that loss of K(+) and associated water fluxes from the host lower the pressure barrier to aid ejection of DNA from the virus particles into the host.