Studies on group A (phage tail) bacteriocins of Serratia marcescens. VI. Calcium ion-dependent biological activity of subgroup II bacteriocins.

The biological activity of subgroup II group A (phage tail) bacteriocins of Serratia marcescens against susceptible indicator cells was completely abolished on two defined, Agarose-containing media. The addition of 0.002 M CaC12 to these two media fully restored the lethal activity of these phage tails. Subgroup I phage tail bacteriocins, on the other hand, were found to have no requirement for divalent cations. These observations furnished an additional biological criterion for the differentiation of subgroup I and II phage tail bacteriocins of S. marcescens.