Wyniki wyszukiwania

1

Large-conductance K+ channel openers induce death of human glioma cells

100%

Debska-Vielhaber G., Godlewski M. M., Kicinska A., Skalska J., Kulawiak B., Piwonska M., Zablocki K., Kunz W. S., Szewczyk A., Motyl T.

Journal of Physiology and Pharmacology

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2009

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tom 60

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nr 4

27-36

Large-conductance Ca2+-activated K+ channels (BKCa channels) are highly expressed in human glioma cells. It has been reported that BKCa channels are present in the inner mitochondrial membrane of the human glioma cell line LN229. In the present study we investigated whether BKCa-channel openers, such as CGS7181 (ethyl 2-hydroxy-1-[[(4-methylphenyl)amino]oxo]-6-trifluoromethyl-1H-indole-3-carboxylate) and CGS7184 (ethyl 1-[[(4-chlorophenyl) amino]oxo]-2-hydroxy-6-trifluoromethyl-1H-indole-3-carboxylate), affect the functioning of LN229 glioma cell mitochondria in situ. In the micromolar concentration range CGS7181 and CGS7184 induced glioma cell death. Morphological and cytometric analyses confirmed that both substances trigger the glioma cell death. This effect was not inhibited by the pan-caspase inhibitor z-VAD-fmk. Lack of DNA laddering, PARP cleavage, and caspase 3 activation suggested that glioma cell death was not of the apoptotic type. We examined the effect of CGS7184 on mitochondrial membrane potential and mitochondrial respiration. Potassium channel opener CGS7184 increased cell respiration and induced mitochondrial membrane depolarization. The latter was dependent on the presence of Ca2+ in the external medium. It was shown that CGS7184 induced an increase of cytosolic Ca2+ concentration due to endoplasmic reticulum store depletion. In conclusion, our results show that CGS7181 and CGS7184 induce glioma cell death by increasing the cytosolic calcium concentration followed by activation of calpains.

2

Histochemical studies on developing embryo of Fasciola hepatica. III. Selected enzymes of respiratory chain

100%

Humiczewska M.

Zoologica Poloniae

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1996

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tom 41

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nr 1-4

3

Role of the non-catalytic subunits of the eukaryotic respiratory complexes. Why are these complexes much larger than their prokaryotic equivalents?

100%

Boumans H., Berden J. A., Grivell L. A.

Cellular and Molecular Biology Letters

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1998

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tom 03

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nr 3

The eukaryotic respiratory complexes carry out conserved reactions compared to their prokaryotic equivalents and contain conserved catalytic subunits. Despite these resemblances, eukaryotic complexes are more complex, containing additional subunits. Various lines of evidence suggest that these additional subunits protect against proteolysis, modulate catalytic activity and/or play a role in assembly. We suggest, however, that none of the present-day functions was the original driving force for their acquisition by the complex during evolution of the mitochondrial respiratory chain and that the incorporation was largely accidental, the small accessory subunits possibly being derived from imported presequences.

4

The respiratory chain of rat liver mitochondria as a probe for toxicological tests in water

100%

Bragadin M., Manente S., Jero A., Perin G.

Polish Journal of Environmental Studies

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1998

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tom 07

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nr 3

The respiratory rate of the mitochondrial respiratory chain is very sensitive to many toxins; some toxins enhance, while others slow the respiratory rate. We propose, therefore, a new simple "in vitro" method in order to assess acute toxicity in water using the response of the mitochondrial respiratory chain from rat liver. On the basis of the response we subdivided all tested toxins into two categories and for each toxin the EC50I value (which is the dose of toxin necessary to halve the maximal respiratory rate) and the EC50u value (which is the uncoupler dose necessary to stimulate the respiratory rate up to fifty percent of its maximum value) are calculated. The comparison between EC50 and LC50 values obtained by fish method allowed us to conclude that our method is a good tool for predicting the toxicity response in fish.

5

Cd2plus-promoted mitochondrial permeability transition: a comparison with other heavy metals

84%

Belyaeva E. A., Glazunov V. V., Korotkov S. M.

Acta Biochimica Polonica

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2004

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tom 51

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nr 2

We compared action of Cd2+, Hg2+, and Cu2+ on isolated rat liver mitochondria in the absence of added Ca2+ and Pi. The heavy-metal ions produced dose-dependently: (1) enhanced membrane permeabilizaton manifested in mitochondrial swelling and activation of basal respiration, (2) inhibition of uncoupler-stimulated respiration, and (3) membrane potential dissipation. Among the metals, Cu2+ exhibited maximal stimulatory effect on basal respiration and minimal inhibitory action on DNP-uncoupled respiration whilst Cd2+ promoted the strongest depression of uncoupled respiration and the largest swelling in NH4NO3 medium. Dithiothreitol induced a basal respiration release if added after high [Cd2+] and [Hg2+], and the stimulation was CsA-insensitive.

6

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Effects of nitroglycerin on energy metabolism of rat reticulocytes

67%

Maletic S. D., Kostic M. M.

Journal of Physiology and Pharmacology

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1999

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tom 50

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nr 1

7

The influence of depletion of voltage dependent anion selective channel on protein import into the yeast Saccharomyces cerevisiae mitochondria

67%

Szczechowicz A., Hryniewiecka L., Kmita H.

Acta Biochimica Polonica

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2001

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tom 48

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nr 3

The supply of substrates to the respiratory chain as well as of other metabolites (e.g. ATP) into inner compartments of mitochondria is crucial to preprotein import into these organelles. Transport of the compounds across the outer mitochondrial membrane is enabled by mitochondrial porin, also known as the voltage-dependent an- ion-selective channel (VDAC). Our previous studies led to the conclusion that the transport of metabolites through the outer membrane of the yeast Saccharomyces cerevisiae mitochondria missing VDAC (now termed YVD AC 1) is considerably restricted. Therefore we expected that depletion of YVDAC1 should also hamper protein import into the mutant mitochondria. We report here that YVD AC 1-depleted mitochondria are able to import a fusion protein termed pSu9-DHFR in the amount comparable to that of wild type mitochondria, although over a considerably longer time. The rate of import of the fusion protein into YVD AC 1-depleted mitochondria is dis-tinctly lower than into wild type mitochondria probably due to restricted ATP access to the intermembrane space and is additionally influenced by the way the supporting respiratory substrates are transported through the outer membrane. In the presence of ethanol, diffusing freely through lipid membranes, YVDAC1-depleted mitochon- dria are able to import the fusion protein at a higher rate than in the presence of external NADH which is, like ATP, transported through the outer membrane by facilitated diffusion. It has been shown that transport of external NADH across the outer membrane of YVDAC1-depleted mitochondria is supported by the protein import machin- ery, i.e. the TOM complex (Kmita & Budziñska, 2000, Biochim. Biophys. Acta 1509, 86.94.). Since theTOMcomplex might also contribute to the permeability of themem-brane to ATP, it seems possible that external NADH and ATP as well as the imported preprotein could compete with one another for the passage through the outer mem- brane in YVDAC1-depleted mitochondria.

8

Interaction of an anticancer ruthenium complex HInd[RuInd2CI4] with cytochrome C

67%

Trynda-Lemiesz L.

Acta Biochimica Polonica

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2004

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tom 51

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nr 1

Cytochrome c is an important electron transfer protein in the respiratory chain, shuttling electrons from cytochrome c reductase to cytochrome c oxidase. Extensive chemical modification studies indicate significant electrostatic interactions between these proteins and show that all structural and conformational changes of cytochrome c can influence the electron transport. In the present work we examine the effect of an anticancer ruthenium complex, trans-Indazolium (bisindazole) tetra- chlororuthenate(III) (HInd[RuInd2Cl4]), on the conformation of cytochrome c, the state of the heme moiety, formation of the protein dimer and on the folding state of apocytochrome c. For this purpose, gel-filtration chromatography, absorption second derivative spectroscopy, circular dichroism (CD) and inductively coupled plasma atomic emission spectroscopy (ICP(AES)) were used. The present data have revealed that binding of the potential anticancer drug HInd[RuInd2Cl4] complex to cytochrome c induces a conformation of the protein with less organized secondary and tertiary structure.

Ograniczanie wyników

Large-conductance K+ channel openers induce death of human glioma cells

Histochemical studies on developing embryo of Fasciola hepatica. III. Selected enzymes of respiratory chain

Role of the non-catalytic subunits of the eukaryotic respiratory complexes. Why are these complexes much larger than their prokaryotic equivalents?

The respiratory chain of rat liver mitochondria as a probe for toxicological tests in water

Cd2plus-promoted mitochondrial permeability transition: a comparison with other heavy metals

Effects of nitroglycerin on energy metabolism of rat reticulocytes

The influence of depletion of voltage dependent anion selective channel on protein import into the yeast Saccharomyces cerevisiae mitochondria

Interaction of an anticancer ruthenium complex HInd[RuInd2CI4] with cytochrome C