Detection of the complex of chromatin DNase-tRNA by gel filtration

By gel filtration on Sephadex G-100, the formation of the complex of chromatin DNase-tRNA has been detected. The complex is reactivated after RNase treatment. The molecular weight of the enzyme-inhibitory complex is estimated to be 85,000.     

Intra- and interspecific host discrimination in Asobara (Hymenoptera) larval endo-parasitoids of Drosophilidae: Comparison between closely related and less closely related species

Host discrimination studies were conducted with different species of Asobara, which are larval endo-parasitoids of Drosophilidae. Results indicated variable host discrimination which depended on the relatedness of the species. The closely related sibling species Asobara tabida (Nees) and A. rufescens (Foerster) were not only capable of intraspecific discrimination, but also avoided multiparasitism by discriminating between unparasitized host larvae and larvae previously parasitized by females of the other species. This ability to discriminate interspecifically does not seem functional as each species occupies its own microhabitat. As it was shown to be absent in less closely related Asobara species we concluded that interspecific discrimination by A. tabida and A. rufescens was due to their close relationship.     

Stable paper indicator systems for rapid identification of microorganisms]

The authors prepared under experimental-industrial conditions paper indicator systems for the express identification of microbes, including carbohydrate discs (by the method of Nikitin et al.), and newly worked out types for the determination of the activity of cytochromoxidase, urease, indol formation, and indicator amino acid decarboxylases (lysin, ornithin, arginine). The use of paper indicator discs proved to be expedient for rationalization of laboratory diagnosis of bacterial intestinal infections.     

Characteristics of the normal gluconeogenesis effect of prostaglandin F2 alpha and in myocardial infarct

The effect of PGF2 alpha on glucose synthesis de novo in a healthy rat organism and those with coronary occlusion-myocardial infarction was studied. There was observed prostaglandin's metabolic action simultaneously at one direction: there was increased the concentration of non-nitric precursors of gluconeogenesis in blood of animals of both groups, final disintegration product of tissue proteins, the gluconeogenic activity of key enzymes and therefore the concentration of newly formed glucose went up as so as glycogen in liver, cardiac and skeletal muscle. Seemingly, PGF2 alpha stimulates the intensity not only of gluco-, but glyconeogenesis having cardioprotective action. At the same time metabolic effect of PGF2 alpha is strongly marked in coronary occlusion rat with myocardial infarction.     

Covalent interaction of L-2-amino-4-oxo-5-chloropentanoic acid with rat renal phosphate-dependent glutaminase. Evidence for a specific glutamate binding site and of subunit heterogeneity

Rat renal phosphate-dependent glutaminase is rapidly inactivated by incubating with L-2-amino-4-oxo-5-chloropentanoic scid. Concentrations of phosphate, which increase the glutaminase activity, decrease the rate of inactivation by chloroketone. In addition, inactivation is not blocked by glutamine. Instead, glutamate was shown to specifically reduce the rate of chloroketone inactivation. Upon sodium lauryl sulfate-polyacrylamide gel electrophoresis, the purified glutaminase preparation exhibits at least five protein staining bands which range in molecular weight from 57,000 to 75,000. Studies with 14C-labeled chloroketone indicate that this reagent reacts with each of these peptides. The mean stoichiometry of binding was calculated to be 1.3 mol/mol of enzyme. Therefore, these results indicate that the glutaminase may contain a specific site for binding glutamate and that the purified enzyme consists of a series of related peptides which may have resulted from partial proteolysis.