Adsorption of bacteriophage under various physiological conditions of the host

Abstract

The first step in the growth of bacteriophage is the combination of phage with the susceptible bacterial host. The rate of this combination is, under simple conditions, proportional to both the bacterial concentration and to the phage concentration. Various aspects of this process have been studied quantitatively by previous workers (1, 2). Their results will be analyzed and discussed in the sections entitled "Residual free phage," and "Theory of adsorption rates." The main purpose of this paper was the study of a detail of the adsorption process that had not previously received attention, namely the dependence of the rate constant of adsorption on the physiological state of the bacterial host. Such a dependence must be anticipated for two reasons. First, it is known that the size of a bacterium changes very considerably depending on its phase of growth in a given culture medium, and an increased cell surface should lead to an increase of the adsorption rate on to a given number of bacteria. Second, for motile bacteria, like E. coli, the adsorption will be faster when the bacteria move about rapidly than when their motility is reduced by adverse physiological conditions. Our experiments show that the rate constant under optimal conditions is more than sixty times greater than under poor conditions.

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