The effect of myelopid on antibody formation in gamma-irradiated animals

The effect of a new immunocorrecting preparation, Myelopid, on the antibody-forming cell content of mouse spleen after gamma-irradiation (1-3 Gy) has been investigated. The preparation administered after immunization of mice with sheep erythrocytes increases the number of antibody-forming cells in the spleen, the effect being a function of radiation dose and time interval between the exposure and immunization. The preparation is ineffective when delivered after irradiation, but prior to immunization.     

Use of Saccharomyces cerevisiae for the clarification of fruit juices

Summary The present work demonstrates that a strain of Saccharomyces cerevisiae that exibits all three types of pectinolytic activities is able to degrade pectins with varying esterification levels.thus participating in the clarification phenomena of fruit juices.We finally compare the clarification potential of that strain with the one of several commercially available pectinolytic mixes.     

Biological activity of gamma-irradiated serum albumin

Gamma-irradiated serum albumin activated L-tyrosine oxidation to 3,4-dioxyphenyl alanine (DOPA) and forms adducts with DOPA oxidation products. These adducts are more resistant to proteolysis and have bactericidal and mutagenic capacity. A possible role of such adducts in a radiation damage to the organism is discussed.     

The effect of physiologically active compounds on the production of ethylene and the activity of polygalacturonase inhibiting protein in fruits

The treatment of apple and banana fruits with 2-CEFA and ethacyde induced the production of ethylene and accelerated the ripening and accumulation of ACC in apple fruits. Inhibitors AOA, AVG, and CoCl₂ acted at the different steps of ethylene biosynthesis, inhibited the physiological aging process and increased storage longevity. Treatment with astaxantine and BOA delayed the pick of ethylene production by fruits. The content of PGIP was correlated with intensity of ethylene production. The infection of fruits with phytopathogenic microorganisms lowered as the result of the inhibition of pathogen PG. The dynamics of PGIP activity in fruits suggests its important role in the processes of ripening.     

The effect of lead on DNA repair in thymocytes of gamma-irradiated mice

The effects of Pb on the repair of DNA have been studied in the thymocytes of gamma-irradiated mice exposed to diacetate lead in the drinking water (up to 20 mg/l) for 14-50 days. It is found that lead causes no DNA degradation by itself and renders its genotoxic action indirectly, via inhibiting the repair of single-strand DNA breaks induced by acute gamma-irradiation of mice. Genotoxic effect of lead is reversible that becomes evident when exposed animals are maintained on Pb-free drinking water for 1-2 weeks.     

The dynamics of the ornithine decarboxylase activity in chronically gamma-irradiated rats]

Ornithine decarboxylase activity changes in some tissues of chronically gamma-irradiated rats (0.54 cGy/h). The radiation effect is a function of the life span of continuously exposed animals. The data obtained indicate that adaptation is possible, at a metabolic level, with the restricted chronic gamma-irradiation of animals.     

The effect of sulfite on the yeast Saccharomyces cerevisiae

After a short period of tolerance, living cells of Saccharomyces cerevisiae were irreversibly damaged by low concentrations of sulfite. The length of the period of tolerance and the rate of the damaging effect depended on the concentration on sulfite, pH-value, temperature, the physiological state of the cells, and incubation time.Inhibitors of protein synthesis and mitochondrial ATP synthesis did not alter the deleterious effect of sulfite on living cells. Furthermore, cell damage leading to inhibition of colony formation occured under aerobic as well as under anaerobic conditions.Prior to cell inactivation sulfite induced the formation of respiratory deficient cells.The active agent was shown to be SO₂.     

The effect of repeated bouts of backward walking on physiologic efficiency

Previous studies have demonstrated an increased energy expenditure with novel tasks. With practice, the energy cost decreases as the body more efficiently recruits motor units. This study examined whether one becomes more efficient after repeated bouts of backward walking. The subjects were 7 healthy subjects between the ages of 23 and 49 years. A backward walking speed was calculated to elicit a VO(2) equal to 60% of the VO(2)max. There were 18 training sessions at the prescribed walking speed 3 d x wk(-1) for 20 min x d(-1). The backward walking speed required to elicit a fixed VO(2) increased between weeks 4 and 6 of the training period. This finding suggests that backward walking is indeed a novel task and that motor learning occurs as a result of practice, leading to a more efficient recruitment of motor units.     

Antiviral effect of commercial juices and beverages.

Nineteen commercial juices or beverages were tested for inactivation of poliovirus type 1. Grape and apple juices and tea were particularly antiviral. Although antiviral in aqueous solution, ascorbic acid was ineffective after addition to juices.     

The effect of superhelical density on the yield of single-strand breaks in gamma-irradiated plasmid DNA.

Using agarose gel electrophoresis, the formation of DNA single-strand breaks (SSBs) by 137Cs gamma irradiation was quantified in negatively supercoiled topological isomers of plasmid pUC18. The G value for SSB formation falls slightly from 1 x 10(8) to 8 x 10(-9) SSB Gy-1 Da-1 as the superhelical density varies from 0.00 to -0.08. This result is not in agreement with recent observations by others which suggest that increasing the negative superhelical density of plasmid DNA increases its sensitivity to X irradiation.     

Antiviral effect of commercial juices and beverages.

Nineteen commercial juices or beverages were tested for inactivation of poliovirus type 1. Grape and apple juices and tea were particularly antiviral. Although antiviral in aqueous solution, ascorbic acid was ineffective after addition to juices.     

The effect of inorganic phosphate on the ethylene production in tomato and apple fruits

Tomato fruits on stems immersed in phosphate solution 0.2 M K₂HPO₄ produced less ethylene than control fruits on stems immersed in water. Phosphate mediated inhibition of ethylene production was found to be the highest in fruits in the pink stage of maturity, which produced ethylene at the highest rate. Phosphate also inhibited ethylene production in slices prepared from maturing fruits, both apple and tomato. We suggest that phosphate is an inhibitor of ethylene biosynthesis in sufficiently mature tomato and apple fruits in which the rise of ethylene production is already very rapid. Presented at the International Symposium “Plant Growth Regulators” held on June 18–22, 1984 at Liblice, Czechoslovakia.     

A comparative analysis of the antioxidant activity of Kalanchoe juices

A study of the biological, including the antioxidant, activity of various medicinal plants with the aim of searching for the most active sources of biologically active compounds among them is, at present, of interest. In the present work, a comparative analysis of the antioxidant activity of juices from 14 Kalanchoe species, measured by the ammetric, voltammetric, and chemiluminescence methods has been performed. Among the samples examined, two members of the Kalanchoe genus were shown to have the highest antioxidant activity: Kalanchoe scapigera and K. rhombopilosa. They may appear to be richer sources of biologically active compounds compared with the currently used Kalanchoe species.     

Proteinase activity of the peripheral blood cell nuclei of gamma-irradiated rats

Immediately after gamma-irradiation of rats a dose-dependent increase in the activity of alkaline and Ca-dependent proteinases was exhibited by leukocyte nuclei. In nuclei of granulocytes, in contrast to those of lymphocytes, radiation activation of proteinases was more pronounced.