Tag Archives: hydrogen peroxide

Nicotinamide influence on pancreatic cells viability

Т. М. Kuchmerovska1, G. V. Donchenko1, T. M. Tychonenko1, M. M. Guzyk1,
R. V. Stavniichuk1, L. V. Yanitska2, S. P. Stepanenko1, А. P. Klimenko1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Bogomolets National Medical University, Kyiv, Ukraine;
e-mail: kuch@biochem.kiev.ua

The study was undertaken to investigate the modulating effect of nicotinamide (NAm) in different concentrations and under different glucose concentrations on the viability and oxidative stress induced by streptozotocin (STZ, 5 mmol/l) and hydrogen peroxide (H2O2, 100 µmol/l) on isolated rat pancreatic cells of the Langerhans islets in vitro. Cell viability did not depend on the concentration of glucose in the range of 5-20 mmol/l, and in subsequent studies we used glucose in concentration of 10 mmol/l to protect cells against its hypo- and hyperglycemic action. Cytoprotective effect of NAm in concentrations from 5 to 20 mmol/l on cells survival was the same. It was found that the destructive action of STZ and H2O2 during 24 hours on isolated cells of the pancreas resulted in the significant cell death. It was revealed that NAm in concentration of 5 mmol/l not only had cytoprotective effects against STZ and H2O2 but also partially reduced the level of oxidative stress in the investigated cells induced by these compounds. High concentration of NAm, 35 mmol/l, causes cytotoxic effect on the viability of pancreatic islet cells and increase of oxidative stress induced by STZ and H2O2.
Most likely these effects could be associated with direct modulatory action of NAm on important effector mechanisms involved in cell death, including PARP-dependent processes, or/and indirectly, through metabolic and antioxidant effects of the compound.

Generation of active oxygen forms in rat tymocytes under action of hydrogen peroxide and fullerene C(60)

S. M. Grebinyk, I. I. Grynyuk, S. V. Prylutska, O. P. Matyshevska

Taras Shevchenko Kyiv National University, Ukraine;
e-mail: grebnik_z@yahoo.com

The dynamics of active oxygen forms (AOF) generation in rat thymocytes 50 min after treatment with 0.1 and 0.5 mM H2O2 was estimated with the use of fluorescent probe DCFDA. Both enhanced AOF generation, which was dependent on H2O2 concentration, and glutathione peroxidase and superoxide dismutase activation, followed by a decrease of thymocytes viability were demonstrated.
Preincubation of cells with 10-5 M fullerene C60 was shown not only to prevent H2O2 – induced AOF generation but to increase viability of H2O2-treated thymocytes at more prolonged time period. The data obtained indicate to fullerene C60 ability to prevent oxidative stress in thymocytes.

Signal function of cytokinin 6-benzylaminopurine in the reaction of Triticum aestivum L. mesophyll cells to hyperthermia

M. M. Musienko, V. V. Zhuk, L. M. Batsmanova

ESC Institute of Biology, Taras Shevchenko National University of Kyiv, Ukraine;
e-mail: zhuk_bas@voliacable.com

The signaling effect of 6-benzylaminopurine (BAP) on leaf mesophyll cells of Triticum aestivum L. under hyperthermic conditions was studied­. It was found that BAP regulated photosynthetic pigment, hydrogen peroxide content and activity of antioxidant enzymes, namely superoxide dismutase, ascorbate peroxidase and catalase under high-temperature conditions. The additive effect of BAP and high temperature on the activation of cell antioxidant systems was demonstrated. BAP regulated reducing processes in mesophyll leaf cells under high-temperature conditions.

The influence of iron ions on ATP-hydrolases activity of cell membranes of rat colon smooth muscle and kidney

A. A. Kaplia

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: kaplya@biochem.kiev.ua

To elucidate the specific features of the АТР- hydrolases structural resistance in the membrane under the action of the prooxidants: Fe2+ and hydrogen peroxide, and N-ethylmaleimide (NEM)  the colonic smooth muscle (CSM) Na+,K+-AТРase activity was compared with activities of the corresponding Mg2+-АТР-hydrolase and ATP-ases from kidney medullar layer of rats. The inhibition study of the CSM Na+,K+-AТРase by divalent iron shows the decrease of the activity by 30% at 0.1 µM FeSO4 and in the range of 0.1-10 µM – to 45% of residual activity. When comparing with kidney enzyme (represents exclusively α1-isozyme) the CSM Na+,K+-AТРase sensitivity to Fe2+ is reliably higher at its submicromolar concentration. CSM Mg2+-АТРase is much more resistant to iron ions effect, than kidney one. However for two tissues Mg2+-АТРase activi­ty is always more resistant as compared with corresponding Na+,K+-AТРase activity. Against 1 mM EGTA Na+,K+-AТРase and Mg2+-АТРase activities of GMOK and kidneys are equally insensitive to effect of hydrogen peroxide in concentration up to 1 mM. But in the presence of 20 µM FeSO4 in the concentration range of 1 nМ – 1 mM of Н2О2 the Na+,K+-AТРase is inhibited to greater extent, than Mg2+-АТРase activity. NEM sensitivity of the two АТР-hydrolase systems corresponds to prooxidant sensitivity that indicates the distinct importance of SH-groups for their functioning. It is concluded that Na+,K+-AТРase can serve as a marker of membrane sensitivity to oxidation, Mg2+-АТРase is resistant to oxidation and can be considered as criterion of the oxidation resistance when comparing  membrane enzyme complexes, especially in GMOK.

Analysis of creatine kinase activity with evaluation of protein expression under the effect of heat and hydrogen peroxide

A. D. Rakhmetov1, Lee Sang Pil2, L. I. Ostapchenko1, Chae Ho Zoon2

1Education and Science Center Institute of Biology Taras Shevchenko National University of Kyiv, Ukraine;
2Chonnam National University, Gwangju, South Korea;
e-mail: anar.rakhmetov@gmail.com

Protein oxidation has detrimental effects on the brain functioning, which involves inhibition of the crucial enzyme, brain type creatine kinase (CKBB), responsible for the CK/phosphocreatine shuttle system. Here we demonstrate a susceptibility of CKBB to several ordinary stressors. In our study enzymatic activity of purified recombinant brain-type creatine kinase was evaluated. We assayed 30 nM concentration of CKBB under normal and stress conditions. In the direction of phosphocreatine formation hydrogen peroxide and heat treatments altered CKBB activity down to 26 and 14%, respectively. Also, examination of immunoblotted membrane patterns by SDS-PAGE electrophoresis and western blot analysis showed a decrease in expression levels of intrinsic CKBB enzyme in HeLa and A549 cells. Hence, our results clearly show that cytosolic CKBB is extremely sensitive to oxidative stress and heat induced inactivation. Therefore, due to its susceptibility, this enzyme may be defined as a potential target in brain damage.