[Mechanisms of mitochondrial dysfunction development in vessels upon peroxidizes LDL influence].

The mechanisms of mitochondrial dysfunction development in vessels upon peroxodized LDL (pLDL) influence are discussed. Is is shown that the components of pLDL induce the formation of covalent complexes with cell proteins and destabilize cellular membrane microdomain structure that leads to membrane proteins dysfunction, Ca2+ liberation into cytosol from its stores, endoplasmic reticulum stress, increase in reactive oxygen species production by NADPH-oxidases. These effects cause disturbances in mitochondria of target cells, increases in reactive oxygen species production, mitochondrial pathway of cell death. The processes under discussion contribute to the atherosclerotic leisure development.

[Comparative analysis of mitochondrial and nuclear DNA topoisomerase I from maize].

We conducted a comparative study of the properties of topoisomerase I isolated from maize nuclei and mitochondria. We found that nuclear and mitochondrial enzymes possess different ability to bind single stranded DNA. Study of the enzyme activity dependence on Mg2+ demonstrated an absolute dependence of the mitochondrial topoisomerase activity. Contrary, nuclear enzyme activity was not absolutely dependent but stimulated by the magnesium cation. Mitochondrial topoisomerase formed covalent bond with the 5'-end of the cleaved DNA what is unique property of prokaryotic topoisomerase I. Nuclear enzyme bound covalently to the 3'-end like all eukaryotic topoisomerases I. The search through databases revealed genes which could encode mitochondrial topoisomerase I in the genomes of higher plants. Using both cDNA sequencing and in silico methods we demonstrated an existence of the ortholog gene in the maize genome. This gene shares significant homology with prokaryotic topoisomerase I genes that may explain differences in the properties of the mitochondrial and nuclear enzyme. Data obtained is of a significant interest both from the point of view of plant organelle evolution and mitochondrial genome expression mechanisms study.

[Isolation of mitochondrial DNA binding proteins which are specific for maize cox1 promoter].

We purified DNA binding proteins which interact with the promoter region of cox1 gene from maize mitochondria. Presence of poly[dIdC-dIdC] and KCl in concentrations up to 500 mM had no influence on binding efficiency demonstrating high specificity of complexes formed. Surprisingly, we did not detect DNA binding when probes containing promoter regions of other mitochondrial genes (cox3, rrn26) were used. Mobility shift competition studies also suggest that the protein posseses binding specificity towards cox1 promoter. The core motif AAGTA proved to be necessary for DNA binding. Using combination of EMSA and elution of proteins from PAG we showed that DNA-protein complex formed contains three polypeptides with molecular mass 60, 44 and 22 kD. We suggest that the isolated proteins may play an important role in the regulation of plant cox1 gene transcription.

[Editing of the mitochondrial cox3 transcript may yield a new site of protein-protein interactions in wild cereal Elymus sibiricus L]. / Redaktirovanie transkripta gena cox3 v mitokhondriiakh dikorastushchego zlaka Elumus sibiricus L. mozhet privodit' k obrazovaniiu novogo uchastka belok-belkovogo vzaimodeistviia.

With PCR, RT-PCR, and direct sequencing, complete nucleotide sequences were established for the Elymus sibiricus mitochondrial cytochrome c oxidase subunit 3 gene (cox3) and its cDNA. The cox3 transcript was shown to have 12 editing sites with changes affecting the amino acid sequence of the protein product. The editing of the primary cox3 transcript was found to change the position of a site of protein-protein interactions. The results demonstrate again the important role of mRNA editing in posttranscriptional regulation of the expression of plant mitochondrial genes.

[Reconstruction of the phylogenetic position of larch (Larix sukaczewii Dylis) by sequencing data for the trnK intron of chloroplast DNA]. / Rekonstruktsiia sistematicheskogo polozheniia listvennitsy sukacheva (Larix sukaczewii Dylis) po dannym sekvenirovaniia trnK introna khloroplastnoi DNK.

To reconstruct the systematic relationships of larch Larix sukaczewii, we used the chloroplast trnK intron sequences of L. decidua, L. sukaczewii, L. sibirica, L. czekanovskii, and L. gmelinii. Analysis of phylogenetic trees constructed using the maximum parsimony and maximum likelihood methods showed a clear divergence of the trnK intron sequences between L. sukaczewii and L. sibirica. This divergence reaches intraspecific level, which supports a previously published hypothesis on the taxonomic isolation of L. sukaczewii.

[Specific features of nucleic acid synthesis in mitochondria of Elymus sibiricus from different natural populations]. / Osobennosti sinteza nukleinovykh kislot v mitokhondriiakh pyreinika sibirskogo (Elymus sibiricus) raznykh prirodnykh populiatsii.

Conditions and kinetic characteristics of nucleic acid synthesis were studied in the isolated mitochondria of Elymus sibiricus from different natural populations. The results showed the reciprocal dependence of RNA and DNA synthesis rates in the mitochondrial genetic system of E. sibiricus seedlings of different genotypes.

Identification of highly conserved hydrophobic amino acid motif in deduced amino acid sequence of Elymus sibiricus L. mitochondrial S13 ribosomal protein.

The nucleotide sequence of mitochondrial ribosomal protein rps13 gene from wild perennial grass Elymus sibiricus is presented. It was determined by the method of PCR amplification with specific oligonucleotide primers and the direct sequencing of the amplification product. The sequence of E. sibiricus mitochondrial gene for S13 predicts a hydrophobic ribosomal protein of 116 amino acids that shows strong similarity to those of wheat (99.7% identity) and maize (98%). The deduced amino acid sequence of S13 protein from E. sibiricus and homologous plant's (Zea mays, Daucus carota, Nicotiana tabacum, Marchantia polymorpha) and nonplant's (Escherichia coli) proteins shows the presence of hydrophobic amino acids' motif -L-X10-L-X10-M-X10-L-X10-L-. Slightly modified it can be found in many other ribosomal proteins. This conserved motif is presumed to be particularly important for association of the ribosomal S13 protein with other proteins in the small subunit of the mitochondrial ribosome.

[An unusual leucine motif in amino acid sequences of subunit 9 of ATP-synthase from plant mitochondria, modified by mRNA editing]. / Neobychnyi leitsinovyi motiv v aminokislotnykh posledovatel'nostiakh sub''edinitsy 9 ATP-sintazy rastitel'nykh mitokhondrii, modifitsiruemyi putem redaktirovaniia mRNK.

The amino acid sequences of subunit 9 of plant mitochondrial ATP-synthase contain a leucine motif which differs from the leucine repeat earlier detected within the composition of proteinaceous products of Myc, Fos, and Jun proto-oncogens. The structural organization of this repeat in proteolipid sequences can be modified via transformation of serine triplets into leucine ones as a result of editing of an appropriate mRNA.

[Changes in oxidative phosphorylation in rat liver mitochondria during the development of cholestasis]. / Izmeneniia okislitel'nogo fosforilirovaniia v mitokhondriiakh pecheni krys pri razvitii kholestaza.

Kinetic patterns of oxydative phosphorylation were studied in rat liver mitochondria in dynamics of cholestasis and after addition of bile acids to mitochondria in vitro. Within the 1 and 3 days of cholestasis mitochondrial synthesis of ATP was decreased due to inhibition of ATP and ADP transport by the bile acids. At the period within 3 and 15 days uncoupling of the oxidative phosphorylation occurred; the phenomenon observed might be a result of impairment in the structure of inner mitochondrial membrane.

[Relationship between the systems of activation of fatty acids and ademine nucleotide translocase in the mitochondria]. / Vzaimootnoshenie sistemy aktivatsii zhirnykh kislot i adeninnukleotidtranslokazy v mitokhondriiakh.

Experiments were conducted on freshly isolated rat liver mitochondria and mitochondria subjected to ageing by two different methods. It was shown that the work of the mitochondrial system of fatty acid activation could lead to inhibition of the adenine nucleotide transport through the internal mitochondrial membrane. Inhibition of adenine nucleotide translocase was eliminated by preincubation of mitochondria with carnitine. The presence in the mitochondrial preparations of fatty acids in the concentration adequate for induction of inhibition of addition of CoA and ATP served as a preculiarity of adenine nucleotide translocase inhibition of the ageing mitochondria. The data obtained permitted to make a supposition on the participation of acyl-CoA formed by the mitochondrial acyl-CoA-synthetase in the regulation of adenine nucleotide transport into the mitochondria.

[Mitochondrial respiration and the state of adenine nucleotide phosphorylation in rat liver following multiple administration of 3-methylcholanthrene and phenobarbital]. / Dykhanie mitokhondrii i sostoianie fosforilirovaniia adeninnukleotidov pecheni krys pri mnogokratnom vvedenii 3-metilkholantrena i fenobarbitals

After 4 injections of phenobarbital (PB), 3-methylcholantrene in olive oil (MC) or olive oil alone the corresponding concentrations of acyl-CoAs in the liver (in per cent to control) were: 73, 167, 230. The liver mitochondria from rats injected with oil and MC showed inhibition of the metabolic state 3 respiratory rate after Chance, Preincubation with carnitine elimated this inhibition. In accordance with these data the blood ketone body level in the administration of PB, MC and oil were 31, 136, and 342%, respectively. The phosphate potential value declined only after the injections of olive oil when the ATP concentration in the liver was markedly diminished. The AMP concentration doubled in the liver of rats after the PB and oil injection. Comparison of the data on the induction of microsomal monoxigenases by PB and MC permitted to draw a conclusion that there was a different metabolic fate of acyl-CoAs in these two cases.

[Possible role of adenine nucleotide transport in regulating the respiration of rat liver mitochondria]. / Vozmozhnaia rol' transporta adeninukleotidov v reguliatsii dykhaniia mitokhondrii pecheni krys

Studies with liver mitochondria from rats which starved for 48 hours showed the rate of ADP-stimulated respiration to be 20% lower than in the presence of an uncoupler. This effect was eliminated by preincubation of mitochondria with carnitine. Mitochondria from fed rats were characterized by a considerable decrease of states 3 and 4 respiration. In this case carnitine produced no effect. Preincubation of mitochondria from the liver of fed rats with alpha-ketoglutarate resulted in a substantial increase of the states 3 and 4 respiratory rates. There proved to exist at least two types of regulation of adenine nucleotide transport through the inner mitochondrial membrane depending on the metabolic state of the organism, i.e. by inhibition of adenine-nucleotide translocase by cytoplasmic acyl-CoAs and by control of intramitochondrial adenine nucleotide pool.