MODIFICATION BY HEXITOLS AND SUGARS OF CHANGES INDUCED IN YEAST BY STARVATION. II. CELLULAR DEPLETIONS AND SUGAR BINDING.
ARMY MEDICAL RESEARCH LAB FORT KNOX KY
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Losses of 260 millimicrons absorbing material from yeast cells during incubation in solutions of hexitols or sugars were not correlated with the capacity of incubated cells to produce CO2 from glucose. Depending upon the compound used, resulting rates of CO2 output were greater as well as less than that of cells incubated in water. NAD content was not related, but ATP contents below average occurred in cells showing a lag period and low rates of output thiamine pyrophosphate and decarboxylase activity levels reduced output in some cases. Glucose, sorbose and mannitol uptake was immediate and was high in cells with high rates of CO2 output, and calculated internal concentrations of sorbose and mannitol exceeded medium concentrations in these cases. Both cell size and intracellular sugar space were similar in incubated cells, except for the small cells resulting from incubation in 0.1M glucose. Measurements of sorbose and mannitol exit showed that binding of these compounds occurred. Binding resistant to extraction by boiling water was not as extensive as that shown by exit measurements. Chromatograms of cell extracts showed that sorbose and mannitol were not converted to other compounds, and chemical assays confirmed that uptake was greater by cells incubated in hexitols and certain sugars. Thus, high sugar uptake depended upon binding, and was correlated with high rates of CO2 output the data indicate that compartmentation of cell intermediates also was involved in regulating CO2 output. Author