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Abstract
SUMMARY: Radioactive glucose has been supplied to starved and unstarved cells of the fungus Zygorrhynchus moelleri for short periods of time, and a partial analysis was made of the nature of those substances incorporating radiocarbon from labelled glucose. It was found that although glucose was metabolized more rapidly by unstarved cells it rapidly entered the cells in both nutritional states and was converted to a number of other substances within the first 15 sec. Differences were found in the pattern of incorporation of labelled carbon between starved and unstarved cells, suggesting that starvation resulted in a disturbance of the balance of the relative metabolic pathways utilized for glucose metabolism in unstarved cells.
In further experiments cells were prepared in four physiological states: growing, resting after growth, starved in buffer, and after metabolizing glucose for several hours subsequent to starvation. By use of substrates variously labelled with radiocarbon it was found that the extent of recycling in the tricarboxylic acid cycle, which is similar in growing and resting cells, rose considerably when the cells were starved, and remained high for several hours during the incubation of starved cells with glucose. The minimum percentage of glucose which was metabolized primarily at the Ci position rose from 11 % in growing cells to 19 % in resting cells, fell nearly to zero immediately following starvation, and increased to 5 % after some hours in the presence of glucose.
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