Tag Archives: lipid peroxidation
The activity of prooxidant-antioxidant system in loach embryos under the action of microwave radiation
M. M. Yaremchuk, M. V. Dyka, D. I. Sanagursky
Ivan Franko National University of Lviv,Ukraine;
e-mail: m.yaremchuk@i.ua
Electromagnetic radiation (EMR) affects biological organisms, primarily on the cellular level. However, the effects of EMR at low-intensity exposure on animals and state of metabolic systems are not fully defined yet. Thus, research of microwave radiation influence on the processes of lipid peroxidation and antioxidant protection system is important for understanding the mechanisms of EMR action on the cell, in particular, and organism development on the whole. The content of lipid peroxidation products – lipid hydroperoxides, thiobarbituric acid reactive substances and the activity of antioxidant enzymes – superoxide dismutase, glutathione peroxidase and catalase in loach embryos under the action of microwave radiation (GSM-900 MHz, SAR = 1.1 Vt/kg) lasting 1; 5; 10 and 20 min during early embryogenesis were studied. It has been found that content of lipid peroxidation products in germ cells undergoes significant changes under the action of low-intensity EMR. The effect of microwave radiation (1, 5, 10 min) leads to the increase of superoxide dismutase activity, nevertheless, 20 min exposure decreased this index to the level of control values as it is shown. It has been established that EMR at frequencies used for mobile communications reduce the activity of antioxidant protection system components, especially catalase and glutathione peroxidase. The growth of catalase activity at the 10-cell stage of blastomere division (P < 0.05) is an exception. The results of two-way analysis of variance attest that microwave radiation factor causes the large part of all observable modifications.
Functions of tocopherols in the cells of plants and other photosynthetic organisms
V. M. Mokrosnop
M. G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv;
e-mail: VictoryM6@yandex.ua
Tocopherol synthesis has only been observed in photosynthetic organisms (plants, algae and some cyanobacteria). Tocopherol is synthesized in the inner membrane of chloroplasts and distributed between chloroplast membranes, thylakoids and plastoglobules. Physiological significance of tocopherols for human and animal is well-studied, but relatively little is known about their function in plant organisms. Among the best characterized functions of tocopherols in cells is their ability to scavenge and quench reactive oxygen species and fat-soluble by-products of oxidative stress. There are the data on the participation of different mechanisms of α-tocopherol action in protecting photosystem II (PS II) from photoinhibition both by deactivation of singlet oxygen produced by PS II and by reduction of proton permeability of thylakoid membranes, leading to acidification of lumen under high light conditions and activation of violaxanthin de-epoxidase. Additional biological activity of tocopherols, independent of its antioxidant functions have been demonstrated. Basic mechanisms for these effects are connected with the modulation of signal transduction pathways by specific tocopherols and, in some instances, by transcriptional activation of gene expression.
Laureates of the Palladin Prize of the National Academy of Sciences of Ukraine (1997–1998)
R. P. Vynogradova, V. M. Danilova
Palladin Insitute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: valdan@biochem.kiev.ua
V. A. Baraboi received the O.V. Palladin prize in 1997 for the series of works “The role of lipid peroxidation in the mechanism of ionizing radiation damage and stress”. O. Iu. Petrenko, O. M. Sukochov, L. P. Kravchenko were awarded the O.V. Palladin prize in 1998 for the series of works “The function of intracellular structures in isolated hepatocytes depending on the metabolic status and the effects of low temperatures”.