Abstract
The lysis of bacteria by phage has been considered as a simple plasmolysis, quite different from autolysis, and in fact many attempts to detect protein split products in the solution after lysis have failed. Bronfenbrenner and Hetler, 1 however, did find evidence for the appearance of protein split-products in solution after lysis and hence concluded that lysis was due to hydrolysis of the protein of the bacterial cell.
Meyer, Palmer, Thompson, and Khorazo 2 have reported the appearance of non-protein nitrogen during lysis of Sarcina by lysozyme.
The detection of minute amounts of protein split-products in culture-media is a difficult matter but the loss of protein may be readily and accurately followed provided the culture-medium itself contains little or no protein.
In the present experiments bacteria were grown on the protein-free yeast-extract media previously described. 3 The quantity of cells in suspension was determined by comparing the turbidity of the suspension in water with that of a standard casein-suspension by means of a Klett photoelectric colorimeter. This figure was called “water-insoluble protein” and was found to agree quite closely with the protein-content of growing bacterial suspensions as determined by Kjeldahl determinations of the centrifuged and washed sediment.
A second turbidity-measurement was made on a sample of the suspension diluted in 2% trichloracetic acid. This figure is called “total protein.”
The relative changes in those 2 quantities is best shown by plotting the water-insoluble protein of each sample against the total protein for the same sample. The changes in water-insoluble protein and total protein during growth and lysis have been determined for Staphylococcus aureus, Staphylococcus musca, B. coli, and B. megatherium. The changes in the staphylococcal cultures during autolysis under anaerobic conditions 4 have also been determined.
Get full access to this article
View all access options for this article.