. The chemical activities of bacteria. Bacteria. 80 THE FORMATION OF ENZYMES IN Bx\CTERIA harvested at different ages of culture we find that {a) cells harvested very early in the growth period have neither enzyme; (6) cells harvested during the phase of linear growth possess a very active hydrogenase but no acetoacetic decarboxylase; and (c) cells harvested at the time of cessation of growth have no hydrogenase activity but a very active acetoacetic decarboxylase. These differences in time of formation can probably be correlated with the fact that the ^H of optimum activity of hydrogenase is
. The chemical activities of bacteria. Bacteria. 80 THE FORMATION OF ENZYMES IN Bx\CTERIA harvested at different ages of culture we find that {a) cells harvested very early in the growth period have neither enzyme; (6) cells harvested during the phase of linear growth possess a very active hydrogenase but no acetoacetic decarboxylase; and (c) cells harvested at the time of cessation of growth have no hydrogenase activity but a very active acetoacetic decarboxylase. These differences in time of formation can probably be correlated with the fact that the ^H of optimum activity of hydrogenase is 8-0, while that of acetoacetic acid decarboxylase is approximately 5, and the ct>>- NUMBERS. TIME OF GROWTH &» Fig. 7. joH of the medium falls from 7 to ca. 4-5 during the growth period. It might be thought that some changes in the chemical composition of the cell during its growth should be demon- strable in view of the marked alterations in enzymic constitu- tion. Changes in enzymic constitution involve changes in protein constitution, but these may relate to the organisation of the amino-acids within the molecules, rather than to gross changes in their proportions. However, in recent years, workers in Sweden have applied the technique of ultra-violet spectrophotography to bacteria and have found very significant changes in the composition of the cell during growth. Sub- stances containing purines'and pyrimidines, such as nucleotides. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Gale, E. F. (Ernest Frederick). New York, Academic Press
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Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectbacteria
