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Alteration of a Host Character by Infection with RNA Phage Qβ
Author(s) -
Miyake Tadashi,
Yanagisawa Keiko,
Watanabe Itaru
Publication year - 1966
Publication title -
japanese journal of microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0021-5139
DOI - 10.1111/j.1348-0421.1966.tb00302.x
Subject(s) - biology , lactose , rna , lac operon , population , microbiology and biotechnology , strain (injury) , enzyme , lactose permease , gene , genetics , permease , biochemistry , escherichia coli , demography , anatomy , sociology
ABSTRACT An F + strain of E. coli K 12, W‐2241 has a genetic constitution lac – ( i + z + y – ), str‐r . The inability of this strain to utilize lactose is due to a deletion at the y locus controlling formation of an enzyme permease and therefore, a true lac + revertant can not be expected. The strain, however, produces many colonies on minimal lactose agar medium, when it is plated after infection with RNA phage Qβ, while much fewer colonies are observed on the same medium seeded with uninfected cells. In analyzing this phenomenon, we discovered that these LAC + colonies were not the result of a mechanism similar to transduction but produced by a mechanism related to phage liberation, and that the colonies originated from Qβ + , const cells. The data suggest the following working hypothesis for the mechanism by which LAC + colonies are produced in a population of W‐2241 cells infected with phage Qβ. Constitutive cells carrying Qβ produce intracellular β‐galactosidase and at the stage of phage liberation, the enzyme is liberated into the medium, hydrolyzing lactose to form glucose. Since glucose could be utilized by all of the cells on the medium, the Qβ + , const cell acts as a colony forming center. The phenomenon described in this paper shows a new type of virus‐host relationship which may have some bearing on the influence of animal or plant viruses on host tissues.