Role of calcium and related ions in proliferation of lactic streptococcus bacteriophage.

Calcium is necessary for multiplication of several strains of lactic streptococcus bacteriophage while not required for growth of host bacteria (Shew, 1949; Reiter, 1949; Cherry and Watson, 1949; Collins et al., 1950; Potter and Nelson, 1952b). However, the mode of action of this ion has remained obscure. Calcium action in other bacteriophage systems has been investigated, but disagreement as to function of the ion is to be found in the literature. This may be due largely to differences in the details of the processes by which new viral particles are formed. Puck (1949) and Adams (1949) reported that, while calcium was required for multiplication, coliphages were adsorbed and stopped bacterial multiplication whether this ion was present or not. The latter author indicated that absence of calcium seemed to block bacteriophage development at a very early stage. Delbrukck (1948) demonstrated an adsorption cofactor role for calcium in the case of a mutant type of coliphage T4. Rountree (1951) found that calcium was required for adsorption of at least some staphylococcal bacteriophages. Kay (1952) concluded that the calcium requirement of a coliphage was for intracellular multiplication. The work to be presented in this paper strongly suggests that, in the case of the lactic streptococcus bacteriophage system, calcium and related ions function in the process of bacteriophage invasion of host cells. The term invasion as used here means penetration by attached bacteriophage or orientation of reactive groups of bac-