Bacteriophate-Induced Functions in Escherichia coli K(λ) Infected with rII Mutants of Bacteriophage T4

Abstract

RUTBERG, BLANKA (Karolinska Institutet, Stockholm, Sweden), AND LARS RUTBERG. Bacteriophage-induced functions in Escherichia coli K(X) infected with rII mutants of bacteriophage T4. J. Bacteriol. 91:76-80. 1966.-When Escherichia coli K(X) was infected with rII mutants of phage T4, deoxycytidine triphosphatase, one of the phage-induced early enzymes, was produced at initially the same rate as in r+-infected cells. Deoxyribonuclease activity was one-third to one-half of that of r+infected cells. This lower deoxyribonuclease activity was observed also in other hosts or when infection was made with rI or rIII mutants. Presence of chloramphenicol did not allow a continued synthesis of phage deoxyribonucleic acid in rIh-infected K(X). No phage lysozyme was detected nor was any antiphage serum-blocking antigen found in rIh-infected K(X). It is suggested that the rII gene is of significance for the expression of phage-induced late functions in the host K(X). The structure of the rII gene of phage T4 is known in its most intimate details (4), but the physiology of the rII gene is still largely unknown (9, 11, 13, 20). The aim of the present work was to study some phage-specific products induced by infection with T4rII of its nonpermissive host Escherichia coli K(X). Production of deoxycytidine triphosphatase and deoxyribonuclease was chosen to represent early functions of the phage genome; among late functions, phage lysozyme and antiphage serum-blocking antigen were studied. In the experiments concerning deoxyribonuclease activity, rI and rIII mutants were included. MATERIALS AND METHODS Bacterial strains. E. coli B, E. coli Bc (E. coli B cured from its defective prophage) E. coli K (C 600 of Appleyard (3)), and E. coli K(X). The bacterial strains were kindly provided by G. Bertani.

Bacteriocinlike killing action of a temperate bacteriophage phiBA1 of Bacillus aneurinolyticus

“…Physiology of infected cells. Physiological changes of host cells have been reported in the course of killing by bacteriocin (38) or by phage which showed abortive infection (8,10,27,32,33,38,42). To clarify the events occurring in the course of killing in the KA10-4BA1 system, we examined the physiological changes in KA10 cells after XBA1 infection, using KA23 as the control.…”

“…abortive infection (8,10,27,32,33,38,42), killing-sensitive bacteria carry a prophage or harbor a plasmid. Screening for plasmid DNA in B. aneurinolyticus strains revealed the existence of three or more covalently closed circular DNA of different molecular sizes in some of the killing-sensitive strains (e.g., KA17; approximate molecular sizes of 2, 7, and 20 megadaltons).…”

“…In some bacteria-virus interactions, an abortive infection has been reported as a phenomenon in which no progeny phage are produced and the host cell is killed (8,10,27,32,33,38,42). In these cases, phage DNA is injected normally into the host cell and the normal infectious process starts, but the presence of a prophage or a plasmid dictates that the normal events cease before the production of progeny.…”

“…Although a number of particulate and soluble bacteriocins from different sources have been shown to possess killing activity on a narrow range of related bacteria (for high-molecular-weight bacteriocins, see reference 4), little is known about bacteriocinlike killing action of a complete phage which does not accompany the expression of the phage genome. The limited cases of killing action of a complete phage include the abortive infection of Escherichia coli phage (8,10,27,33), Salmonella phage (38), and Bacillus subtilis phage (32,42) onto sensitive hosts which are lysogenic for another prophage or carry a plasmid. We are not aware of any example of killing activity of a complete phage which is independent of the expression of phage DNA or which is active on an apparently prophagefree host.…”

Control of Gene Function in Bacteriophage T4

“…DNA but not of late proteins (7) and the T4 synthesis in rII-infected K(X) without concomitant appearance of late proteins (10,14) show that phage DNA synthesis is not a sufficient condition for transcription of late T4 genes, although it is a necessary one. If it were also a necessary condition for maintaining the synthesis of late T4 messenger (m) ribonucleic acid (RNA), interruption of DNA synthesis should arrest the synthesis of late T4 mRNA.…”