- Adsorption of bacteriophage under various physiological conditions of the host. Delbrück, M. (1940). J. Gen. Physiol. 23:631-642. The first step in the growth of bacteriophage is the combination of phage with 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 (Krueger, 1931, J. Gen. Phsyiol. 14:493; Shlesinger, 1932, Infectionskrankh. 114:136-149). 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. Frist, 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 B. 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. [TOP OF PAGE]
- The growth of bacteriophage and lysis of the host. Delbrück, M. (1940). J. Gen. Physiol. 23:643-660. 1. A new strain of B. coli and of phage active against it is described, and the relation between phage growth and lysis has been studied. It has been found that the phage can lyse these bacteria in two distinct ways, which have been designated lysis from within and lysis from without.
2. Lysis from within is caused by infection of a bacterium by a single phage particle and multiplication of this particle up to a threshold value. The cell contents are then liberated into solution without deformation of the cell wall.
3. Lysis from without is caused by adsorption of phage above a threshold value. The cell contents are liberated by a distension and destruction of the cell wall. The adsorbed phage is not retrieved upon lysis. No new phage is formed.
4. The maximum yield of phage in a lysis from within is equal to the adsorption capacity.
5. Liberation of phage from a culture in which the bacteria have been singly infected proceeds at a constant rate, after the lapse of a minimum latent period, until all the infected bacteria are lysed.
6. If the bacteria are originally not highly in excess, this liberation is soon counterballanced by multiple adsorption of the liberated phage to bacteria that are already infected. This leads to a reduction in final yield. [TOP OF PAGE]
- Studies with bacteriophages active against mucoid strains of bacteria. Rakieten, M.L., Eggerth, A.H., Rakieten, T.L. (1940). J. Bacteriol. 40:529-545. [TOP OF PAGE]
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