| Abstract: | The utilization of glucose by Scenedesmus quadricauda has beenstudied by manometric methods. With small amounts the oxidationonly goes to about 16 per cent. of completion, the remainderof the glucose being built up into an acid-hydrolysable polysaccharidewhich is not starch, and which is built up from a hexose otherthan fructose. The extent of the oxidation is not affected by sodium azideor 2:4-dinitro-phenol, but can be varied by altering the pHof the suspension medium; more oxygen is absorbed per unit weightof glucose at pH 8 than at pH 5. It is suggested that there is no fixed relation between thetwo processes of oxidation and synthesis, as has previouslybeen suggested, but that the glucose, after phosphorylation,saturates the oxidation system, and the excess hexose-phosphateis built up into a polysaccharide. Mannose is also utilized in the same way, but at a slower rate,and less oxygen is used up compared with glucose. Galactosegives only a slight stimulation of the respiratory rate, andfructose, sucrose, and lactose are not absorbed. |
