Tag Archives: reactive oxygen species
The ROS-generating and antioxidant systems in the liver of rats treated with prednisolone and vitamin D(3)
I. O. Shymanskyy, A. V. Khomenko, O. O. Lisakovska,
D. O. Labudzynskyi, L. I. Apukhovska, M. M. Veliky
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ishymansk@inbox.ru
The mechanisms of glucocorticoid-induced disturbances of liver function is currently not fully clarified. Vitamin D3 was previously shown to play an important role in the regulation of impaired oxidative metabolism and detoxification function of the liver associated with the effects of hepatotoxic compounds. The study was undertaken to define the intensity of oxidative metabolism in the rat liver and survival of hepatocytes after prolonged prednisolone administration and to assess whether vitamin D3 is capable to counter glucocorticoid-induced changes. It has been shown that prednisolone (0.5 mg per animal for 30 days) leads to 1.6-fold increase in the percentage of necrotic cells among isolated hepatocytes as compared with the control. The glucocorticoid-induced impairment of hepatocellular function was accompanied by enhanced generation of reactive oxygen species (ROS), accumulation of TBA-active products and carbonylated proteins but reduced levels of free SH-groups of low molecular weight compounds. It was demonstrated a decrease in the activities of key enzymes of antioxidant system (SOD, catalase, glutathione peroxidase), whereas the activities of pro-oxidant enzymes NAD(P)H-quinone oxidoreductase and semicarbazide-sensitive amine oxidase were shown to be increased. Vitamin D3 (and to greater extent in combination with α-tocopherol) administration (100 IU) on the background of glucocorticoid therapy caused normalizing effects on the level of ROS formation, oxidative modification of biomolecules and activity of antioxidant enzymes resulting in better survival of hepatocytes. These data suggest a potential role of vitamin D3 in the regulation of oxidative metabolism alterations related to hepatotoxic action of glucocorticoids.
Reactive oxygen species and stress signaling in plants
Yu. E. Kolupaev, Yu. V. Karpets
V. V. Dokuchaev Kharkiv National Agrarian University, Ukraine;
e-mail: plant_biology@mail.ru
Data on the basic processes and the compartments, involved in formation of reactive oxygen species (ROS) in plant cells, are generalised. The features of structure and regulation of NADPH-oxidase as the one of main enzymatic producers of ROS are characterized. The two-component histidine kinases, ROS-sensitive transcript-factors, ROS-sensitive protein kinase and redox-regulated ionic channels are discussed as the possible sensors of redox-signals in plant cells. The interaction between ROS and other signal mediators, in particular nitric oxide and calcium ions, is discussed. The ROS role as the signal mediators in the development of plant resistance to hyperthermia, osmotic shock and other abiotic stressors is analyzed.
The effect of ATP-dependent K(+)-channel opener on transmembrane potassium exchange and reactive oxygen species production upon the opening of mitochondrial pore
O. V. Akopova, L. I. Kolchinskaya, V. I. Nosar, V. A. Bouryi, I. N. Mankovska, V. F. Sagach
Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv;
e-mail: a-dubensky@mail.ru
The effect of mitochondrial ATP-dependent K+-channel (K+ATP-channel) opener diazoxide (DZ) on transmembrane potassium exchange and reactive oxygen species (ROS) formation under the opening of mitochondrial permeability transition pore (MPTP) was studied in rat liver mitochondria. The activation of K+-cycling (K+-uptake and K+/H+-exchange) by DZ was established with peak effect at ≤500 nM. It was shown that MPTP opening as well resulted in the activation of K+-cycling together with simultaneous activation of Ca2+-cycle in mitochondria. In the absence of depolarization Ca2+-cycle is supported by MPTP and Ca2+-uniporter. The stimulation of K+/H+-exchange by MPTP opening led to the activation of K+-cycle, but further activation of K+/H+-exchange resulted in MPTP inhibition. Under the same conditions the decrease in mitochondrial ROS production was observed. It was proposed that the decrease in ROS formation together with K+/Н+-exchange activation could be the constituents of the complex effect of MPTP inhibition induced by K+ATP-channel opener.
Metalloproteins during development of Walker-256 carcinosarcoma resistant phenotype
V. F. Chekhun, Yu. V. Lozovska, A. P. Burlaka, I. I. Ganusevich,
Yu. V. Shvets, N. Yu. Lukianova, I. M. Todor, D. V. Demash,
A. A. Pavlova, L. A. Naleskina
R. E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology,
National Academy of Sciences of Ukraine, Kyiv;
e-mial: Lozovskaya.2012@mail.ru
The study was focused on the detection of changes in serum and tumor metal-containing proteins in animals during development of doxorubicin-resistant phenotype in malignant cells after 12 courses of chemotherapy. We found that on every stage of resistance development there was a significant increase in content of ferritin and transferrin proteins (which take part in iron traffick and storage) in Walker-256 carcinosarcoma tissue. We observed decreased serum ferritin levels at the beginning stage of the resistance development and significant elevation of this protein levels in the cases with fully developed resistance phenotype. Transferrin content showed changes opposite to that of ferritin. During the development of resistance phenotype the tumor tissue also exhibited increased ‘free iron’ concentration that putatively correlate with elevation of ROS generation and levels of MMP-2 and MMP-9 active forms. The tumor non-protein thiol content increases gradually as well. The serum of animals with early stages of resistance phenotype development showed high ceruloplasmin activity and its significant reduction after loss of tumor sensitivity to doxorubicin. Therefore, the development of resistance phenotype in Walker-256 carcinosarcoma is accompanied by both the deregulation of metal-containing proteins in serum and tumor tissue and by the changes in activity of antioxidant defense system. Thus, the results of this study allow us to determine the spectrum of metal-containing proteins that are involved in the development of resistant tumor phenotype and that may be targeted for methods for doxorubicin sensitivity correction therapy.
Role of Ca ions in the induction of heat-resistance of wheat coleoptiles by brassinosteroids
Yu. E. Kolupaev1, A. A. Vayner1, T. O. Yastreb1, A. I. Oboznyi1, V. A. Khripach2
1V. V. Dokuchaev Kharkiv National Agrarian University, Ukraine;
e-mail: plant_biology@mail.ru;
2Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus;
e-mail: khripach@iboch.bas-net.by
The involvement of Ca2+ into the signal transduction of exogenous brassinosteroids (BS) (24-epibrassinolide – 24-EBL and 24-epicastasterone – 24 ECS) causing the increase of heat resistance of the cells of wheat (Triticum aestivum L.) coleoptiles was investigated using calcium chelator EGTA and inhibitor of phosphatidylinositol-specific phospholipase C – neomycin. Twenty-four-hour treatment of coleoptile segments with 10 nM solutions of 24-EBL and 24-ECS led to a transient increase in the generation of superoxide anion radical by cell surface and the subsequent activation of superoxide dismutase and catalase. Pretreatment of coleoptiles with EGTA and neomycin depressed to a considerable extent these effects and leveled the increase in heat resistance of wheat coleoptiles that were caused by BS. Possible mechanisms of involvement of calcium signaling into the formation of reactive oxygen species in plant cells and induction of heat resistance of plant cells by the action of exogenous BS have been discussed.