RESUMO
The growth of cyanophage N-1 in the cyanobacterium Nostoc muscorum under the influence of heavy metal ions, namely Co2+, Cr6+, Cu2+, Mn2+ and Ni2+ has been studied. One-step growth experiments revealed that heavy metal ions extended the latent period by 1-2 hrs with a concomitant decrease in the phage burst size. The latter was reduced in the order Cu2/Mn2+, Ni2+, Co2+ and Cr6+. The treatment of the phage-infected bacteria with heavy metal ions did not induce mutations affecting either the phage plaque morphology or burst size. The final phage titer after such a treatments was lowest with Co2+, Cu2+ and Cr6+. The inhibition of the phage growth under the influence of heavy metal ions is discussed in context with the interaction of cyanophage N-1 with the photosynthetic reactions in the host bacteria.