RADIOSENSITIVITY OF SEVERAL DEHYDROGENASES AND TRANSAMINASES DURING SPOROGENESIS OF BACILLUS SUBTILIS

Abstract

Rowley , D. B. (Syracuse University, Syracuse, N.Y.), and H. R. Newcomb . Radiosensitivity of several dehydrogenases and transaminases during sporogenesis of Bacillus subtilis . J. Bacteriol. 87: 701–709. 1964.—Cells of Bacillus subtilis grown in a chemically defined medium for 17 hr, subsequently washed, and transferred to a phosphate solution containing CaCl 2 sporulated in a reproducible pattern. The synthesis of dipicolinic acid essentially paralleled the appearance of thermoresistant cells. X-ray resistant cells appeared 2 to 3 hr before the appearance of thermoresistant cells and the formation of dipicolinic acid. Changes in enzyme activity of cells undergoing sporogenesis varied among the enzymes studied. The transaminases exhibited a marked decrease in activity during early sporogenesis, whereas the dehydrogenases exhibited maximal activity. The determination of enzyme radioresistance in extracts of sporulating cells indicated that the resistance of transaminases remained essentially unchanged, whereas the dehydrogenases exhibited a decreased resistance early in sporogenesis. Although both glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase (GOT) were demonstrated in vegetative cells, only the latter was detected in mature spores. The radioresistance of GOT in vegetative-cell extracts was two to three times greater than in spore extracts.