The action of the tumour promoter, TPA, on mutagenesis induced by different agents (UV light, chemical and viral mutagens)

The present paper deals with effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the frequency of induced mutations to 6-mercaptopurine (6MP) and ouabain resistance in Chinese hamster and mouse cells. UV light, bovine adenovirus 3(BAV-3) and 5-bromodeoxyuridine (BrdU) were used as mutagens. TPA was shown to raise the frequency of gene mutations induced by UV light and BAV-3 but it did not enhance the mutagenic effect of BrdU. We also examined the ability of BAV-3 and BrdU to induce tumours in mice. BrdU was shown to have no carcinogenic effect. The results suggest that TPA enhances the mutagenic effect only for carcinogenic mutagens.     

Effect of carbohydrates and polyols on amide content and protein fragmentation in a lactoglobulin preparation

Certain carbohydrates and polyols are used at various stages of the production of immunobiological preparations as stabilizers of biological activity, particularly in the production of lactoglobulin (against opportunistic pathogens) using membrane ultrafiltration. This study concerns the effect of these substances on changes in the amide content in proteins of this lactoglobulin. Lactoglobulin was incubated in near-physiological (0.9% NaCl, pH 5.5) 10% solutions of glucose, fructose, and sorbitol at 4 and 35°C for 7, 14, and 28 days. A lactoglobulin solution in 0.9% NaCl, pH 5.5, was used as the control. All substances studied suppressed the reduction of the amide group content of asparagine and, in contrast, increased the rate of amide group removal from glutamine residues in proteins of lactoglobulin preparations.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 1, 2005, pp. 29–34.Original Russian Text Copyright © 2005 by Bibov, Vachaev, Sorokina, Lukash, Sinichkin, Yagovkin.     

Mutagenic activity of native and inactivated herpes simplex virus

The mutagenic activity of native and inactivated herpes simplex virus (HSV-1) has been studied. The native HSV-1 strain has been shown to induce the gene mutations of 6-mercaptopurine resistance in Chinese hamster cells. The 1.5- to 2-fold decrease of mutagenic activity is due to HSV inactivation by thiophosphamide and formalin treatment. These data indicate the possibility of the given agents application for decreasing of the genetic danger of antiviral vaccine.     

Iron-containing proteins and the proteolytic activity in the blood serum in hyperbaric oxygenation and the protective action of urea

The number and composition of ferro-containing proteins, the total number of iron, summary peroxidase activity and peptide-hydrolase activity have been determined under different hyperbaro-oxygenation (HBO) in blood serum. It has been established that under HBO the concentration of ferro-containing proteins increases, the fraction composition of serum and erythrocyte haemoglobin changes, the activity of acid peptide-hydrolases increases and the protamine-splitting peptide-hydrolase activity lowers. The administration of urea before HBO-experiments leads to the normalization of the most biochemical indicators of blood serum. The tests of oxygen intoxication depth assessment have been suggested.     

Changes in the proteolytic activity of tissues during aging

The intensity of proteolytic processes and qualitative composition of autolysis products of the brain, liver and testicle tissues of young and old rats were studied. The gel-chromatographic analysis (Sephadex G-15 and G-50) revealed no considerable amount of high-molecular peptides (1500 Da and over) before and after autolysis. The measurement of the quantity of free amino groups in the gel-chromatographic fraction after the complete acid hydrolysis has confirmed that result. The low-molecular peptides and free amino acids, are the main products of the tissue autolysis. The intensity of proteolytic processes, determined by an increase in the amount of amino acids depends on the autolysis duration and age of animals. The total increment of amino acids in the brain and liver tissues of old animals for the first hour of autolysis has been higher by 102 and 219% as compared to young ones. The autolysis of testicles of the young and old animals after the first hour of incubation is characterized by the same intensivity. Such a regularity is not revealed when analyzing the same processes by the Lowry method.