SUMMARYAutolytic glucanase and protease activity was detected in cell walls of some pythium species prepared by ultrasonic treatment. The glucanase activity was correlated with mycelial development. Maximal glucose release was detected in growing cultures during the linear growth period of the fungus. Assays of glucanase activity in cell walls prepared from mycelium harvested at different times showed that the enzymic activity increased with the age of mycelium from which the cell walls were prepared. The relationship between autolytic enzymes and mycelial development is discussed.
Hyphal cell walls were prepared by ultrasonication. Glucose was the only sugar detected in both species. Evidence was obtained indicating that the Pythium butleri Subram. glucan is beta 1,2-linked, and that the glucan of Pythium myriotylum Drechsler is beta 1,4-linked. Sixteen amino acids were detected in P. butleri cell wall hydrolysates. Four of these amino acids were absent from P. myriotylum preparations. Similar quantities of lipid were found in both species. The significance of these data for fungal classification is discussed.
Abstract. Germinating peanut cotyledons and germinating castor bean endosperm have been compared with respect to their rates of fat dissimilation and with respect to the anatomical distribution of respiratory activity. The lipid mobilization is much slower in peanut cotyledons than in castor bean endosperm. Light hais essentially no effect on either system. As germination progresses, the majority of the succinic dehydrogenase and cytochrome oxidase activities become looalized in the vein regions of peanut cotyledons. In the castor bean endosperm these two activities are uniformly distributed throughout the storage parenchyma and increase with germination until the organ becomes soft and visibly senescent.Castor bean endosperm and peanut cotyledons have been used frequently for biochemical studies on the fate of storage fats during germination. Recently soluble preparations which are able to catalyze the ,8-oxidation of higher fatty acvl-CoA derivatives were obtained from castor bean endosperm (17) and peanut cotyledons (12, 13, 14). The possibility that these soluble preparations might be obtained byr damaging the mitochondria during isolation has not been excluded but this appears unlikely in viewv of the mild procedure used, involving low-speed blending in buffers containing hypertonic sucrose. Regardless of the actual localization of these enzymes, it seems probable that the utilization of storage lipids is dependent uipon mitochondrial activity because ATP is required for the activation of fatty acids and because the reduced pyridine and flavin nucleotides formed during the fl-oxidation pathway must be re-oxidized by the mitochondria in order to produce ATP. In resting seeds the mitochondrial activity is extrenmely low. Mitochondrial development has been studied in germinating peanut cotyledons (, 6, 8) and castor bean endosperm (1, 2).
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