Serial Production of Phage from Intracellular Phage Precursor. ∗

Abstract

Recently experimental evidence was advanced indicating that phage production occurs according to the reaction: inactive phage precursor + phage → phage. 1 The particular point of interest in this concept is the dissociation of phage production from what was previously held to be an essential conditioning factor, namely, bacterial growth. Furthermore, there exist authentic models for such a reaction in the autocatalytic transformation of inactive enzyme precursors into the active enzymes when the precursors are brought in contact with small amounts of active enzyme.

To summarize the experimental data it was found by Krueger and Baldwin 1 that under certain conditions cell-free ultrafiltrates of staphylococci added to solutions of bacteriophage resulted in 100% increases in phage activity. In studying the effect of salts on the phage-bacterium reaction it was found that the presence of sodium chloride 2 or sodium sulphate 3 during the phage-bacterium reaction produced a prelytic plateau in the bacterial growth curve for as much as 0.8 hour during which time phage production continued at a normal rate despite the absence of cellular reproduction. Later 4 experiments were reported in which phage production was dissociated from bacterial growth by means of changes in temperature and pH of the medium. Unfortunately these data do not offer conclusive proof that the phage precursor-phage reaction is the normal mode of phage production largely because the yields of precursor in ultrafiltrates are small and irregular and also because the methods used to detect Δ [bacteria] in the pH-temperature experiments were not sufficiently sensitive. Continued attempts to improve the methods for extracting precursor were unsuccessful and for the past year we have been working with a method which demonstrates the phage precursor within the bacterium. The present paper deals with the serial production of phage in separate aliquots, of precursor-containing-bacteria.