Phosphorus Metabolism in Yeast Accompanying an Inhibition of Cell Division by X-Rays

Carbohydrate Metabolism in Yeast Accompanying an Inhibition of Cell Division by X-Rays

“…The changes in carbohydrate constituents of the unirradiated rapidly growing cells in these experiments show, as do the phosphorus compound changes reported in the previous paper (Spoerl and Looney, 1958), the types of biochemical change which must occur in growing -cultures in an unrenewed medium. Changes such as these have only been inferred from differences in lag periods (Prescott, 1957) and other physiological responses.…”

“…A previously used strain of Saccharomyces cerevisiae isolated from a cake of Fleishmann's baker's yeast was used in these studies. Details of culture and handling techniques were described in a previous report (Spoerl and Looney, 1958). Control and continuously irradiated cultures were sampled for analysis at 0, 2, 4, and 6 hr as part of the experiments described previously.…”

“…Growth flasks were aerated by shaking and were incubated at 28.5 C. The yeast carbohydrates were separated into water-extractable, trichloracetic acid (TCA)-extractable, mannan, glucan, and glycogen fractions by the methods of Chung and Nickerson (1954). Cells were centrifuged from the prepared suspension of water washed cells (Spoerl and Looney, 1958), extracted for 30 min with water at room temperature, and then by cold 10 per cent TCA for 10 min. A hot alkali extraction removed mannan and part of the glycogen from the TCA residue.…”

“…Cells were counted in a hemocytometer, and paired cells were counted as two cells if the smaller had a diameter greater than approximately one-half that of the larger cell. Phosphorus and nitrogen analyses of wash waters were by methods described previously (Spoerl and Looney, 1958). A GE Maxitron X-ray machine, operated at 250 kvp and 30 ma, was used for continuous irradiation of yeast cultures.…”

Glucose Uptake and Dissimilation by X-Irradiated, Starved, and Division-Inhibited Yeast

“…were X-irradiated for a 2-hr period (Spoerl and Looney, 1958a;Spoerl et al, 1960). A dose of 2 kr/hr was used (250 kv, 30 ma, 0.5 mm Cu plus 1.0 mm Al added filtration).…”