Abstract
Monovalent cations such as Cs+, Rb+, K+ and Na+, and, to a lesser extent, NH4+ had an inactivating effect on HM 2 phage (group I) and HM 7 phage (group III). The critical concentration of Na+ for inactivation of the phage was between 0.4 and 0.02M with its maximum at 0.1M. Divalent cations such as Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+ and Ni2+, and, to a lesser extent, Cd2+ and Zn2+, had a protective effect on the inactivation of the phage by monovalent cations. The molarity of Na+ for maximum inactivation of the phage was shifted by increasing concentration of Mg2+ added (5×10-4, 1×10-3, 2.5×10-3, 5×10-3 and 1×10-2M, respectively) from 0.1M to 0.3, 0.5, 0.7, 0.9 and 1.5M, respectively. Polyamines such as putrescine and spermidine also had a similar protective effect.