Genetische und physiologische Beziehungen zwischen den Bakteriophagen T1 und D 20

Summary

The close relationship between phages T 1 and D 20 was confirmed by genetical crosses. D 20 could be shown to differ from T 1 by at least two genes, both affecting the host range of the phage. The geneDs will render a phage capable of multiplying on the original host of “D 20”, SF;Ha will enable the phage to lyse B/1. D 20 may thus be formulated as T 1HaDs. Both genes could be localized within the T 1 linkage map, in the vicinity of the geneHr, which is known to control the host range specifity against B/1. The results of genetical, adsorption, and serological studies can be interpreted by the assumption that each gene controls the synthesis of a specific protein, responsible for the adsorption behaviour of the particular phage. A phage will adsorb to SF according to itsDs genotype, to B or its phage resistant mutants according to itsHa genotype. These proteins do not, however, exert their functions independently. Therates of adsorption and neutralization are influenced by the presence or absence of proteins not required for the particular reaction under investigation.