[Effect of point substitutions of Asp-714 and Asp-720 residues on the structure and function of the H+ -ATPase of the yeast plasma membrane].

Membrane-spanning M5 and M6 segments, which play a role in the formation of cation transport sites in H(+)-, Ca2(+)-, K(+)-, Na(+)-, and other P2-ATPases, are connected by a short extracytoplasmic loop. In the yeast plasma membrane H(+)-ATPase, which belongs to a family of P2-ATPases, the loop is connected to M5 and M6 through the Asp-714 and Asp-720 residues. In this work, the effect of point amino, acidreplacements of Asp-714 and Asp-720 by Ala, Val, Asn, and Glu residues on the function of the enzyme was studied. The Asp714Asn point mutant possessed activities similar to those of the wild-type enzyme, whereas the replacement of Asp-714 by other amino acid residues disrupted biogenesis and led to a loss of activity. All mutants with substitution of Asp-720 were expressed and possessed relatively high activity. The D720V mutant displayed significantly reduced expression levels, activity, H+ transport, and ATP hydrolyzing activity. Thus, substitutions of Asp-714, except for the D714N mutant, led to significant defects in biogenesis and/or function of the enzyme. The results indicate the important role for the Asp-714 residue in biogenesis, structure stability, and enzyme function.

[Metabolic changes in wheat (Triticum aestivum L.) plants under action of bioregulator stifun].

Under action of growth-stimulating concentrations of bioregulator stifun on wheat plants, an increase of functional activity of nucleoli of meristematic cells; contents of lectin (wheat germ agglutinin); and activity of proteinases, tripsin inhibitors, and ATPase activity was established. The pool of free amino acids was increased under bioregulator use. Levels of methionine, phenylalanine, cysteine, lysine, and tyrosine were increased. It is likely that stifun could activate protein biosynthesis in wheat plants.

[Evaluation of the activity of hydrolases and their inhibitors using substrates immobilized on agarose gel].

A simple and convenient method for the quantitative evaluation of the activity of hydrolytic enzymes and their inhibitors has been proposed. This method is based on the immobilization of a substrate on agarose gel and the following evaluation of the enzyme activity by measuring the hydrolysis area around the well containing the enzyme solution. The method was shown to be applied to the evaluation of the activity of proteinases and amylases and the inhibitors of these enzymes in different biological objects.

[Human serum insulin-binding component in health and in type 1 diabetes mellitus].

Serum-affine components have been detected in the sera of healthy donors and patients with diabetes mellitus. Human serum has been ascertained to contain insulin-binding component. The latter has not been shown to be immunoglobulin, i.e. it contains no insulin-specific antibodies. The experimental findings suggest that there are human serum proteins that are involved in the transport of insulin.

[Hormonal balance of wheat infected with Helminthosporium sativum]. / Gormonal'nyi balans u pshenitsy, porazhennoi vozbuditelem kornevoi gnili Helminthosporium sativum.

Using immunoenzyme assay, we studied the levels of phytohormones in resistant and susceptible varieties of wheat infected with Helminthosporium sativum. The infection of wheat with this pathogen leads to an increase in cytokinins in plants of the resistant variety in the presence of stable IAA/ABA ratio. The level of ABA increases in the infected plants of the susceptible variety. The role of hormones in the mechanisms of plant resistance to fungal infections is discussed.

[Method for gastric resection with end-to-end gastroduodenal anastomosis]. / Sposob rezektsii zheludka s gastroduodenal'nym anastomozom konets v konets.

The authors suggest a method of stomach resection in which the gastroduodenal anastomosis is created by applying sutures to the layers after separating the sheaths of the organs into layers. The inner sheaths (muco-submucous) of the organs are butt joined after their excision almost at the base, while the outer sheaths (seromuscular) are sutured with rarely placed crimping sutures. The rare placing of the sutures and moderately tight tying of the ligatures prevent impairment of tissue nutrition, whereas crimping of the outer sheath provides wide contact of the serosa. Narrowing of the anastomosis does not occur because the inner sheath is sutured in a butt manner while the ridge formed on the outer sheath is outside the lumen. The wound of the anastomosis heals by first intention. The method was used in 251 patients with various diseases of the stomach and duodenum. Their ages ranged from 13 to 73 years. Most were seriously ill. Two patients died, one from the fibrinolysis syndrome, associated with massive transfusion of blood, and hepatorenal failure, the other died from pancreonecrosis. The sutures of the anastomosis were efficient in both cases. Incompetence of the anastomosis sutures was encountered in one patient. Incompetence of sutures of the closed part of the gastric stump was diagnosed in another patient. Perforation of acute ulcer of the gastric stump occurred in still another patient. All of these patients as well as the other patients recovered.