The Inheritance of Requirements for Adsorption Cofactors in the Bacterial Virus T4

Abstract

A stock prepn. of the bacteriophage T4 contained 3.9 X 1011 plaque-forming particles/ml. on its host Escherichia coli strain B, grown on Difco nutrient agar (N), but only 2.6 X 108 particles/ml. forming plaques on B grown on ammonium lactate agar (F). Individual plaques or clones from this stock appearing on N agar were suspended in F medium and assayed. They gave much lower counts on F agar than on N agar, and this characteristic persisted in sub-clones from these plaques, whether formed on F or on N agar. The majority of individual clones appearing in assay of the stock on F agar, as well as their sub-clones, whether they arose on B or F or on N agar, produced as many plaques on F agar as they did on N agar. The particles in the stock which are efficient in forming plaques on F agar can be removed by absorption on the host in F medium, but more effectively in the presence of the adsorption cofactor for T4, l-tryptophan. It is concluded that the degree of cofactor requirement is inherited in clones of T4.