Role of carbohydrate in determining the immunochemical properties of the major glycoprotein (gp71) of Friend murine leukemia virus.

Treatment of Friend leukemia virus gp71 with protease-free glycosidase enzymes results in removal of the major portion of the carbohydrate without affecting the amount of protein present. The digested material migrates as protein of about 60,000 to 65,000 molecular weight on sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Analyses of the serological properties of gp71 after enzyme treatment indicated that the type, group, and interspecies determinants were not destroyed. In contrast, treatment with proteolytic enzymes led to the complete destruction of the gp71 molecule, including the total elimination of its serological reactivity as measured by direct and competition radioimmunoassay and by a serum cytotoxicity assay. We conclude that the carbohydrate portion of gp71 is not of major significance in defining the antigenic determinants of this viral glycoprotein.     

Some effects of ouabain on cellular ions and water in epithelial cells of toad urinary bladder

The Journal of Membrane Biology - Transepithelial sodium transport was virtually abolished when toad urinary hemibladders, mounted in chambers and short-circuited, were exposed on their serosal...     

Biochemical maturation of human central nervous system myelin.

—A developmental study of the lipid and protein composition of human CNS myelin was undertaken. The relative concentrations of the major lipid classes, cholesterol, glycolipids and phospholipids exhibited little change except for a modest decrease in the concentration of the phospholipids. In contrast to the total phospholipids, marked variations in the relative concentrations of individual phospholipids were found. Sphingomyelin increased over two-fold, and phosphatidyl choline decreased to almost half its original concentration. While the concentration of total myelin protein remained constant during maturation, variations in the concentrations of individual proteins were observed. Basic protein constituted 8·5 per cent of the total myelin proteins in the newborn brain and increased to about 30 per cent of the protein in the older ages. The concentrations of proteolipid protein and DM-20 seemed to increase with age, while the relative amounts of high molecular weight proteins decreased. The presence of myelin basic protein in newborn human brain was confirmed by electrophoretic studies involving several different polyacrylamide gel systems and by immunodiffusion experiments which showed a reaction of identity between a constituent present in the fraction containing the presumptive myelin basic protein and authentic myelin basic protein isolated from adult human brain.     

Die flavonolglykoside von Equisetum silvaticum

Ten glycosides of kaempferol and quercetin, including the hitherto unknown kaempferol and quercetin 3-rutinoside-7-rhamnosides, have been isolated from Equisetum silvaticum L.     

Microbodies and glyoxylate-cycle enzyme activities in filamentous fungi

Summary From compartmental analysis of radioisotope elution measurements, concentrations and fluxes of K⁺, Na⁺ and Cl^- were estimated for cortical cells in root segments of onion, Allium cepa L., relative to a complete nutrient solution. The transported fraction of the total efflux was estimated separately. With the Ussing-Teorell flux ratio equation as the criterion, it was concluded that all three ions were actively accumulated from the outside medium into the cytoplasm and that only Na⁺ was actively accumulated into the vacuole. K⁺ and Cl^- moved passively, in both directions across the tonoplast. Failure to account for leakage from the stele via the segment cut ends resulted in an over-estimate of exchange across the tonoplast but did not alter the conclusions qualitatively. The consequences of changing the assumed value of the tonoplast electrical potential (from 0 to+10- mV), and the effects of different experimental procedures, were also assessed, and found not to affect the main conclusions significantly. Separate measurement of ions leaking from the segment ends revealed that Na⁺ was transported almost exclusively in an acropetal direction in the stele. Cl^- appeared at both ends of the segments in similar amounts and K⁺ was transported mainly in the basipetal direction. The implications of these findings for the mechanism and site of ion selectivity are discussed.     

Biochemical studies on mammalian cardiac muscles: I. distribution pattern of myoglobin in different chambers of the heart of some mammals.

The myoglobin content of atria and ventricles of hearts of some mammals has been studied. The hearts of various mammals exhibit variations in their myoglobin concentration in contrast to earlier reports on various mammals. A definite gradation in the distribution pattern of myoglobin in mammalian cardiac muscles with Left atrium less than Right atrium less than Right ventricle less than Left ventricle, is discernible. There seems to be a close correlation of ventricular myocardium and their functional requirements.