STUDIES ON INTERRELATION BETWEEN VIRUS AND HOST AT THE MOLECULAR LEVEL.

A procedure was devised to separate phage DNA from the cellular one, and to analyse patterns of DNA synthesis in phage epsilon 34kc-infected cells. The results suggest the followings: De novo synthesized phage DNA are at first of linear monomer, then recombine into dimers or polymers, and finally are fragmented into monomers of mature phage DNA size by mechanism requiring head protein synthesis. By using chemical mutagens, 64 ts mutants were isolated from phage epsilon 34k and classified into 10 cistrons by complementation tests. These cistrons plus additional 3 cristrons were mapped into circular form by genetic recombination. Although physically circular DNA has not been demonstrated, the DNA polymerization and the circularity of the map are consistent with each other. Early ts mutants were shown to be able to establish lysogeny without DNA replication in case of high multiplicity of infection. From comparison of adsorption with chemical structures of serological determinant oligosaccharides in various Salmonella strains, receptor for phage g341 has been shown to involve at least o-acetyl-alpha-galactose as an essential structure. On the other hand phage g341 was shown to carry a gene(s) responsible for repression of transacetylation of the host cell, and in regard to this activity genetic cooperation and recombination between phages g341 and epsilon 15a were demonstrated. The significances and bearings of the above findings are discussed. (Author)
See also AD-647 584.