Metabolic Aspects of Cyanophage AS-l Replication and Reproduction in Cyanobacterium Anacystis nidulans

Abstract

Summary The intracellular stages of the cyanophage AS-l replication cycle were investigated under conditions that impair the metabolic functions of the host, Anacystis nidulans . The reproductive cycle of the cyanophage consists of an eclipse period (3.5 h), latent period (7 h) and finally lysis of cells after 14 h with the release of 100–120 PFU/infected cell. Viral multiplication was inhibited in dark. Withdrawal of light before the eclipse period or incubation of the infected cells in the dark for 6 h followed by illumination, decreased the final yield of virus and prolonged the reproductive cycle. The inhibitor of Photosystem II, DCMU, prolonged the latent period and reduced the burst-size to 50–60 % of the control. Inhibitor of electron transport, CCCP, abolished the viral growth completely. Treatment of infected cells with chloramphenicol (100 µ/ml) upto 4 h during the latent period completely abolished the phage growth. However, after 6 h of phage development the infective centres became refractory to chloramphenicol action. Rifampicin and actinomycin D (lOO µ/ml) abolished AS-1 development when treatments were given before the eclipse period. These results demonstrated the dependent virulent nature of the cyanophage AS-1.