Physiology of toxin production by Clostridium botulinum types A and B. I. Growth, autolysis, and toxin production.

The classical concept of exotoxin implies that the toxin is actively excreted into the external environment as a direct product of the organism's metabolic processes. On the other hand, endotoxin is assumed to be a structural component of the cell. From the many reports during the past decade it is apparent that this sharp distinction between the extracellular and intracellular nature of these two classes of bacterial toxins is not completely valid. The three classical exotoxins of Corynebacteriumn diphtheriae, Clostridium tetani, and Clostridium botulinum can be recovered in considerable quantity from the cells by means of solvents (Raynaud and Second, 1949; Boroff et al., 1952; Stone, 1954) and endotoxins can be found in cell-free filtrates (van Heyningen, 1950). Autolysis has been accepted as a general characteristic of the genus Clostridium for many years but it was only recently that a correlation was shown to exist between the autolytic process and the appearance of toxin in the extracellular environment (Boroff, 1955; Stone, 1954). However in view of the conflicting reports found in the literature concerning the rate of toxin production by C. botulinum (Dozier, 1924; Elberg and MIeyer, 1939; Dack et al., 1928; Raynaud et at., 1954, 1955), an investigation was carried out that attempted to correlate the kinetics of cell multiplication and subsequent autolysis, with the appearance of toxin in the extracellular environment.