Phycoerythrin Association with Photosystem II in the Cryptophyte Alga Rhodomonas salina.

# Deceased. Cryptophyte algae belong to a special group of oxygenic photosynthetic organisms containing pigment combination unique for plastids - phycobiliproteins and chlorophyll a/c-containing antenna. Despite the progress in investigation of morphological and ecological features, as well as genome-based systematics of cryptophytes, their photosynthetic apparatus remains poorly understood. The ratio of the photosystems (PS)s I and II is unknown and information on participation of the two antennal complexes in functions of the two photosystems is inconsistent. In the present work we demonstrated for the first time that the cryptophyte alga Rhodomonas salina had the PSI to PSII ratio in thylakoid membranes equal to 1 : 4, whereas this ratio in cyanobacteria and higher plants was known to be 3 : 1 and 1 : 1, respectively. Furthermore, it was established that contrary to the case of cyanobacteria the phycobiliprotein antenna represented by phycoerythrin-545 (PE-545) in R. salina was associated only with the PSII, which indicated specific spatial organization of these protein pigments within the thylakoids that did not facilitate interaction with the PSI.

DNA Aptamers to Thrombin Exosite I. Structure-Function Relationships and Antithrombotic Effects.

DNA aptamers (oligonucleotides) interacting with thrombin exosite I contain G-quadruplex, two T-T, and one T-G-T loops in their structure. They prevent exosite I binding with fibrinogen and thrombin receptors on platelet surface, thereby suppressing thrombin-stimulated formation of fibrin from fibrinogen and platelet aggregation. Earlier, we synthesized original antithrombin aptamer RE31 (5'-GTGACGTAGGTTGGTGTGGTTGGGGCGTCAC-3') that contained (in addition to G-quadruplex) a hinge region connected to six pairs of complementary bases (duplex region). In this study, we compared properties of RE31 aptamer and its analogues containing varying number of bases in the duplex region and nucleotide insertions in the hinge region. Reduction in the number of nucleotides in the duplex region by 1 to 4 pairs (in comparison with RE31 aptamer) resulted in the decrease of the structural stability of aptamers (manifested as lower melting temperatures) and their ability to inhibit thrombin-stimulated fibrin formation in human blood plasma in tests of thrombin, prothrombin, and activated partial thromboplastin times. However, an increase in the number of bases by 1 to 2 pairs did not cause significant changes in the stability and antithrombin activity of the aptamers. Insertions into the hinge region of RE31 aptamer decreased its antithrombin activity. Investigation of RE31 antithrombotic properties demonstrated that RE31 (i) slowed down thrombin formation in human blood plasma (thrombin generation test), (ii) accelerated lysis of fibrin clot by tissue plasminogen activator in in vitro model, and (iii) suppressed arterial thrombosis in in vivo model. Based on the obtained data, RE31 aptamer can be considered as a potentially effective antithrombotic compound.

[Study of the quantity of interleukin-6 by SDS-PAAG electrophoresis and immuno-enzyme analysis in mixed saliva after rinsing the oral cavity with oligonucleotide specific.]

The selective properties of a solution of oligonucleotide specific to IL-6 on the concentration of IL-6 in mixed saliva of patients with oral inflammatory processes were studied using SDS-PAGE by electrophoresis and enzyme immunoassay. The application of these methods showed that in the mixed saliva of patients after rinsing with a solution of an oligonucleotide specific for IL-6, the amount of IL-6 decreases. The ELISA Kit and 20% SDS-PAGE showed the highest sensitivity to determine the concentration of IL-6 in saliva, which should be considered in clinical laboratory practice.

[Biological effect of extracellular peptide factor from Lateococcus japonicas subsp. casei on probiotic bacteria].

The biological effect of the extracellular peptide reactivating factor (RF) from Luteococcus casei on cells of probiotic cultures was studied. The RF showed the protective and reactivating effects on the Bifidobacterium bifidum cells under the action of bile salts and an acidic stress. Also, it acted as a cryoprotector during lyophilisation and long-term culture storage. The RF and the L. casei culture liquid (CL) were shown to have bifidogenic properties. The degree of protection and reactivation of lactic-acid bacteria under the action of bile salts depended on the particular strain properties. The maximum degree of protection (more than thirteen-fold) and reactivation (close to three-fold) was found in Lactobacillus casei, while the minimum values were characteristic of Lactobacillus reuterii. The resistance of lactobacilli to bile was increased in the row of L. acidophilus, L. casei, L. plantarum, L. rhamnosus, and L. reuterii correlating with the RF protection degree.

[Antistress cross-effects of extracellular metabolites of bacteria, archaea, and yeasts: a review].

This paper reviews examples of specific and global responses of microorganisms and the characteristics of stress responses involving extracellular signaling metabolites. Information regarding the protective and reactivating effects produced by active exometabolites of representatives of domains of bacteria, archaea, and eukaryotes is summarized, and interdomain cross-responses to stressors are demonstrated.

[Cardioprotective effect of cytoflavine on a model of doxorubicin-induced cardiomyopathy].

Experimental data on the influence of repeated administration of doxorubicin in a dose of 2.24 mg/kg on the glutathione exchange in heart tissues and erythrocytes of white outbred rats are presented. It was shown that disorders in the natural cytoprotection system caused by the introduction of this cardiotropic agent, can be corrected using a combined preparation of cytoflavin.

[Experimental study on cytoflavin pharmacological correction of cyclophosphamide-induced toxic affections of the liver and kidneys].

The experimental data concerning the influence of repeated administration of cyclophosphamide in a total dose of 200 mg/kg on the glutathione metabolism and lipid peroxidation in the liver and kidneys of albino noninbred rats are presented. The possibility of the natural cytoprotection system correction by the use of cycloflavin was shown. The cytoprotection action mechanisms of the pharmacological agent are discussed.

Complex formation with protamine prolongs the thrombin-inhibiting effect of DNA aptamer in vivo.

Antithrombin DNA aptamersRE31 are single-chain oligonucleotides that fold into three-dimensional forms allowing them to bind the enzyme with high affinity and inhibit its activity in vivo. They are rapidly degraded by a nonspecific nuclease, and, to prolong the lifetime of the aptamer DNA in the bloodstream, it is necessary to coat it with a polymer envelope. A new approach to solving this problem based on preparation of DNA-polyelectrolyte complexes with a minimal particle size that can circulate with blood flow. In our experiments, the negatively charged aptamer DNA RE31 was coated step-by-step with positively charged protamine. They had protamine/aptamer ratios of 0.2/1 and 0.4/1 by charge, with particle size being determined by dynamic light scattering. The aptamer DNA-protamine complexes were administered to rats, followed by ex vivo analysis of blood samples. The results showed that prothrombin time (PT) increased by a factor of 5.6-6.7 within 2 h after injection and remained at approximately the same level for 6 h, while injections of pure protamine did not lead to any noticeable change in clotting time. Thus, complexation with protamine proved to prolong the inhibitory activity of the RE31 DNA aptamer.

[Glutathione metabolism in rat cardiac tissues in acute doxorubicin-induced intoxication].

Experimental data are presented on the influence of acute doxorubicin intoxication with 7.47 and 2.34 mg/kg body mass on glutathione metabolism in cardiac tissues of albino non-inbred rats. Doxorubicin toxic effect resulted in such marked changes as decreased concentration of reduced glutathione and abnormal levels of glutathione reductase, glucoso-6-phoshate dehydrogenase, glutathione peroxidase and glutathione-S-transferase. Possible causes of such biochemical changes as well as their role in causation of doxorubicin cytotoxic effect are discussed. New methods of prophylaxis and lab diagnosis of doxorubicin-induced cardiomyopathy are suggested.

[Correction of free radical processes by a succinic acid drug (reamberine) in intensive care of patients with acute neurotropic poisoning]. / Korrektsiia svobodnoradikal'nykh protsessov preparatom iantarnoi kisloty (reamberinom) v intensivnoi terapii ostrykh otravlenii neirotropnymi iadami.

Sixty-six patients with acute poisonings with neurotropic toxins (soporiphics, neuroleptics, antidepressants, ethanol and its surrogates) were examined and treated. Clinical data and correction of disorders in free-radical processes in acute poisonings with these toxins indicate the efficiency of adding reamberine to combined therapy of this patient population.

[Stress-protective and cross action of the extracellular reactivating factor of the microorganisms of the domains Bacteria, Archaea, and Eukaryota].

Cross protection of members of the domains Bacteria, Archaea, and lower Eukaryota from stress factors due to the action of extracellular low-molecular metabolites with adaptogenic functions was shown. The adaptogen produced by Luteococcus japonicus subsp. casei and described previously as a reactivating factor (RF) was shown to protect the yeasts Saccharomyces cerevisiae, archaea Haloarcula marismorti, and the cells of higher eukaryotes (HeLa) against weak stressor impacts. Production of an archaeal extracellular metabolite with a weak adaptogenic effect of the producer cells and capable of a threefold increase in survival of heat-inactivated yeast cells was discovered. Our results confirm the similarity of the compensatory adaptive reactions in prokaryotes (bacteria and archaea) and eukaryotes.

[Structure of the intracellular part of the motility apparatus of halobacteria].

The electron microscopic study of the structure of the motility apparatus of the archaea Halobacterium salinarium 4W12 and Natronobacterium magadii confirmed our earlier observation that the motility apparatus of halobacteria contains an intracellular disk-shaped lamellar structure (DLS). Polar cap structures (PCSs) isolated from the halobacterium were preliminarily identified as the DLSs. The PCSs in complexes with flagella were also isolated from the haloalkaliphilic bacterium N. magadii. The specific structure of the archaeal motility apparatus is discussed.

[Chemiluminescence in the peroxidase oxidation of luminol with hydrogen peroxide in various media]. / Khemiliuminestsentsiia pri peroksidaznoi reaktsii okisleniia liuminola perekis'iu vodoroda v razlichnykh sredakh.

The effects of culture media of various compositions on chemiluminescence developing in peroxidase oxidation of luminol with hydrogen peroxide were under study. The findings evidence that the presence of carbonate and bicarbonate ions in the medium results in a two-staged chemiluminescence kinetics and in more intensive chemiluminescence in the peroxidase-luminol-hydrogen peroxide system. This fact has brought the authors to a conclusion that carbonate and bicarbonate-containing media are more effective for the detection of low peroxidase concentrations by the chemiluminescence technique.