Effect of physical and chemical agents on the blue-green algal virus N-1

The stability of the blue-green algal virus N-1, infecting the blue-green alga Nostoc muscorum, against temperature, EDTA and pH was studied. Ninety per cent thermal inactivation of virus occured at 55 degrees C in 20 minutes with an average inactivation rate constant of 0.07 per minute; at 60 degrees C the virus was completely inactivated within 5 minutes. 10(-4) M EDTA inactivated 30 per cent of free virus in 60 minutes; 10(-3) M EDTA was completely lethal. Intracellular virus was comparatively resistant to EDTA. The virus was stable in the pH range from 6.7 to 10.5 and was inactivated at acidic pH.