Seasonal variations in frog liver glycogen metabolism (author's transl)

Glycogen metabolism in frog (Rana ridibunda) liver is subject to seasonal variations. Hepatic glycogen and glycogen synthase levels are highest in the fall and winter months and lowest in the summer months, whereas glycogen phosphorylase activity is highest in spring and summer and lowest in fall and winter months. Blood glucose levels show a clear increase during the months of March, June-July and November over the mean level for the rest of year (19.0 +/- 5.5 mg glucose/100 ml serum). Results indicate that the animal accumulated glycogen in the fall to be consumed during the winter. Glycogen levels are in direct proportion to glycogen synthase activity levels (I-form and total activity) and in inverse proportion to glycogen phosphorylase (phosphorylated form) activity levels, which would suggest that these enzymes exercise a direct control over glycogen levels.     

Histochemistry of the carbohydrate metabolism in cysts of Toxoplasma gondii (author's transl)]

Mice were infected with cysts of the ALT strain Toxoplasma by intraperitoneal injection. After 2-8 weeks disseminated cysts could be demonstrated in the brain tissue. All cysts showed identical histochemical characteristics, independent of their sizes or their cell number. The encysted organisms were intensely stained after the PAS-reaction. This polysaccharide is highly diastase and acid resistant. Glycogen synthetase activity could not be demonstrated, but phosphorylase activity was very high. The energy metabolism was characterized by a high lactate dehydrogenase activity, whereas the reaction for succinate dehydrogenase activity only leads to sparse deposits of reaction products. The carbohydrate content is interpreted to be not only a store of energy substrate but also a store of biosynthetic substrate. It is assumed that a part of the liberated glucose at high activities of G-6-P-DH and 6-P-G-DH is metabolized by the hexose monophosphate shunt, the pentoses of which may contribute to nucleic acid synthesis which is necessary for the proliferation of the encysted organisms.     

An improved mouse metabolism cage and its performance tests (author's transl)

An improved mouse metabolism cage, remodeled after the conventional makeshift type to permit accurate measurement of urine volume, avoiding or minimizing fecal contamination of urinary constituents and undue stress on the animal under test, is described. The structure of the cage is illustrated in detail in Figures 1 and 2. The principal points of modification include: 1) a semi-level top surface of the glass globe separator to accommodate the mouse in a less stressful posture of reduced instability; 2) a steeper gradient of the lateral spherical surface of the glass globe separator avoid contamination of urine by feces, drinking water leaks and debris of diet, along with a shortened urine collecting tail (27 mm) and a receptacle for water leaks; and 3) an insulator installed at the bottom to prevent escape of the animal. Performance tests of the cage demonstrated accurate measurements of urine output and water intake and assays of urinary constituents, with complete prevention against escape of mice.