[Molecular characteristics of the chitin-binding peroxidases of plants].

The chitin-binding ability of isoperoxidases isolated from 23 plants of different species was studied. The activation of peroxidases in a protein extract in the presence of this polysaccharide was found for 14 of the studied plants. Anionic isoperoxidases were shown to be sorbed on chitin and eluted from them with 1 M NaCl for 16 of the plant species. Cationic isoforms of the peroxidases of some species of the Fabaceae and Cucurbitaceae plant families also bound to chitin. An immunochemical similarity was found between the chitin-binding isoperoxidases of taxonomically distant plant species (the Pomaceous, Fabaceae, and gourd families). Moreover, a high homology of the molecular structures of the polysaccharide-binding sites was revealed for the anionic peroxidases of rice, wheat, oat, zucchini, cucumber, and radish. We propose the existence of a special class of plant peroxidases that bind with polysaccharides (chitin) and participate in the protective reactions of plants against pathogens.

Kininase of the Latrodectus tredecimguttatus venom: a study of its enzyme substrate specificity.

The specificity of the peptide hydrolyzing action of a highly purified preparation of kininase from Latrodectus Tredecimguttatus venom was studied by the method of TLC on silica gel with the use of various synthetic peptides as substrates. It was shown that the enzyme cleaves the -Pro(7)-Phe(8)-bonds in BK and AI molecules liberating, correspondingly, the C-terminal dipeptide and tripeptide. Exopeptidase specificity was not revealed in the enzyme activity with the use of a number of free and N-substituted tri- and pentapeptides. The results obtained characterize the spider venom kininase as a thiol endopeptidase, which cleaves internal peptide bonds at the proline carboxyl end.

[Effect of chronic gamma irradiation on the protein composition and cholesterol content of the blood of dogs]. / Vliianie khronicheskogo gamma-oblucheniia na belkovyi sostav i soderzhanie kholesterina v krovi sobak.

In a chronic experiment dogs were exposed to irradiation in doses of 190, 360 and 560 rad for 3 years. As compared to the unirradiated controls they showed a slower recovery of the albumin and cholesterol content in the blood. The cholesterol content varied, depending on the dose of chronic irradiation, whereas the protein content did not show such a correlation.

[Changes in the sugar content in the blood of dogs during 6 years of chronic gamma irradiation]. / Izmeneniia soderzhaniia sakhara v krovi u sobak pri 6-letnem khronicheskom gamma-obluchenii.

The paper presents the results of a many-year investigation of the sugar content in dogs irradiated with total doses of 125, 370, 720, 750, 1130 rad. During the first year the sugar content tended to increase and later to decrease. Irradiated and untreated animals showed different reactions to additional loads (running, thermal exposure, acute irradiation). The differences included the direction and level of changes in the sugar content. There was no correlation between the changes and the dose rate. The changes returned to normal after termination of the exposure.

Physiological and hematological effects of chronic irradiation.

The information available for assessing radiation hazard involved in prolonged space missions is so far insufficient. Therefore, a three-year experiment was carried out in which 180 dogs were exposed to irradiation, simulating the dose value and rate of exposure that may occur in a real space flight of long duration. The exposure included a chronic irradiation (with dose rates of 21, 62 and 125 rads/year) and a combined irradiation during which the animals were exposed to chronic and acute irradiations with a dose of 8 or 42 rads applied three times every year, the annual total dose being 120 or 188 rads, respectively. Insignificant hematopoietic changes, e.g. the ratio of red to white blood cells, their decrease in the peripheral blood, were found. Distinct changes in the reproductive function were noted. The general condition of the animals was satisfactory. Most animals endured well an additional physical load and retained conditioned reflexes developed before irradiation. The experimental findings suggest that the effects are early symptoms of the first stage of chronic radiation damage.