Purification and Chemistry of Bacteriophage ϰ

Abstract

From a stock of ϰ phage grown on Salmonella , a host-range mutant which attacks Escherichia coli was isolated. As in the case of Salmonella , only motile strains of E. coli are sensitive to ϰ. The phage shows an eclipse period of 35 min and a minimal latent period of 52 min. The adsorption rate constant is 3 × 10 −9 ml/min. Adsorption shows a marked dependence on temperature. Bacteriophage ϰ was purified by differential centrifugation and CsCl density gradient centrifugation. It contains deoxyribonucleic acid (DNA) which is double-stranded. The DNA has a molecular weight of 42 million and a guanine plus cytosine content of 57%. Of 68 molecules of DNA inspected, 7 were circular. The phage particle weight is about 90 million.