The Effect of Physical and Chemical Changes on the Liberation of Phage Particles by Lysogenic Strains of Salmonella

Publisher Website
Google Scholar
Abstract
In studies on 4 naturally occurring strains and 2 artifically prepared resistant-variant strains of S. thompson, the free-phage bacterium ratio was normally constant, but could be altered by many different physical and chemical stimuli. Phage production was not effected by aeration, anaerobic cultivation, NaCl concn., nor by the addition to the medium of a variety of substances such as proflavine, yeast extracts and many chemical and therapeutic agents. It was decreased by lowering the temp. of incubation to 22[degree], lowering the pH to 5.5 or by adding ascorbic acid, urethane, or high concns. of Na thiolacetate. Phage production was stimulated by the addition to the medium of sulfathiazole, thiolacetate or glutathione. Nitrogen mustard and mustard gas induced lysis in a similar manner to u.-v. and X-rays, and of all the substances tested these were the only 2 more lethal to the phage particles than to the bacteria. Various views on the phenomenon of lysogenicity are examined in the light of the above data.