Characterization of host-range mutants of cyanophage N-1.
Fifteen host-range (h) mutants of cyanophage N-1 were characterized with reference to their efficiency of plating, time of appearance, morphology and size of plaques on Nostoc muscorum and its three phage-resistant (Nm 1/N-1, Nm 2/N-1 and Nm 8/N-1) mutants. While phage N-1 did not adsorb to the three phage-resistant mutants, the h mutants differed one from the other in having lower or higher adsorption rate constants on N. muscorum or the phage-resistant mutants. The inability of majority of h mutants isolated on Nm 1/N-1 to grow in Nm 8/N-1 was shown to be due to a failure of adsorption. The h mutants also differed one from the other in their reversion (back mutation) frequencies. The lethal doses (LD37) required to kill 37% of free phage particles after UV-irradiation, heating and ethylenediamine tetraacetate (EDTA) treatment greatly varied. Most of the h mutants were found to be considerably more sensitive to UV and thermic inactivation than N-1 while they were resistant to EDTA. The h mutants except five of them were unable to multiply at 40 degrees C. The significance of these features is discussed.
Sarma
T A
TA
Department of Botany, Punjabi University, Patiala, India.
Kaur
B
B
D001435:Bacteriophages / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000528:radiation effects; D000458:Cyanobacteria / Q000821:virology*; D004492:Edetic Acid / Q000494:pharmacology; D006358:Hot Temperature; D009154:Mutation; D014466:Ultraviolet Rays; D010948:Viral Plaque Assay
D004492:Edetic Acid