Effect of serotonin on the yield of UV- and x ray-induced DNA damage

Using two-dimensional thin-layer chromatography, the effect of serotonin on the yield of thymine dimers and on cleavage of the N-glycosidic bond in the DNA irradiated with ultraviolet (UV) light and X-ray was studied. Bound serotonin was shown to reduce the synthesis of UV-induced thymine dimers but had no effect on the number of X-ray-induced breaks in the N-glycoside bonds in thymidine residues. The data obtained are discussed in terms of the mechanisms of serotonin involvement in the photoprotection of yeast cells from the lethal action of UV and X-ray irradiations.     

Effect of cortisol, its polymeric derivative and adenylate cyclase activators on the content of cyclic AMP in rat thymocytes

In has been shown that cortisol immobilized on polyvinylpyrrolidone (PVP-GC) affects cyclic AMP production stimulated by adenosine and isoproterenol in rat thymocytes. This effect of PVP-GC is specific for cortisol: antiglucocorticoid progesterone (at a concentration of 10(-5) M) inhibited completely the action of PVP-GC on the intracellular cAMP level. It is suggested that cortisol effect on cAMP production is one of the mechanisms of glucocorticoid hormone action in target cells.     

Cadmium removal from human plasma by Cibacron Blue F3GA and thionein incorporated into polymeric microspheres

Poly(2-hydroxyethylmethacrylate–ethyleneglycoldimethacrylate) [poly(HEMA–EGDMA)] microspheres carrying Cibacron Blue F3GA and/or thionein were prepared and used for the removal of cadmium ions Cd(II) from human plasma. The poly(HEMA–EGDMA) microspheres, in the size range of 150–200 μm in diameter, were produced by a modified suspension copolymerization of HEMA and EGDMA. The reactive triazinyl dye-ligand Cibacron Blue F3GA was then covalently incorporated into the microspheres. The maximum dye incorporation was 16.5 μmol/g. Then, thionein was bound onto the Cibacron Blue F3GA-incorporated microspheres under different conditions. The maximum amount of thionein bound was 14.3 mg/g. The maximum amounts of Cd(II) ions removed from human plasma by poly(HEMA–EGDMA)–Cibacron Blue F3GA and poly(HEMA–EGDMA)–Cibacron Blue F3GA–thionein were of 17.5 mg/g and 38.0 mg/g, respectively. Cd(II) ions could be repeatedly adsorbed and desorbed with both types of microspheres without significant loss in their adsorption capacity.     

Synthesis,Molecular Modeling,and Biological Evaluation of Novel Chiral Thiosemicarbazone Derivatives as Potent Anticancer Agents

A series of new chiral thiosemicarbazones derived from homochiral amines in both enantiomeric forms were synthesized and evaluated for their in vitro antiproliferative activity against A549 (human alveolar adenocarcinoma), MCF‐7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma), and HGC‐27 (human stomach carcinoma) cell lines. Some of compounds showed inhibitory activities on the growth of cancer cell lines. Especially, compound 17b exhibited the most potent activity (IC₅₀ 4.6 μM) against HGC‐27 as compared with the reference compound, sindaxel (IC₅₀ 10.3 μM), and could be used as a lead compound to search new chiral thiosemicarbazone derivatives as antiproliferative agents. Chirality 27:177–188, 2015. © 2014 Wiley Periodicals, Inc.     

Relation between the structural, metabolic and "adhesive" properties of nuclear and cytoplasmic non-ribosomal RNA

Nuclear RNAs release from nucleoproteins of isolated nuclei absorbed on a celite column in a wide range of dissociating conditions (from 1 M LiCl--2 M urea at 2 degrees C to 4 M LiCl--8 M urea at 70-80 degrees C) was demonstrated. Such a high "adhesive" heterogeneity of nuclear RNAs (i.e., variations in the tightness of RNA-protein bonds) appears to be due to the association of nuclear matrix proteins. A direct correlation was found to exist between the metabolic turnover of RNA and the tightness of its association with the nuclear matrix. Actually, the pulse label which rapidly incorporates into the RNAt greater than 50 degrees, the RNA fraction being most tenaciously bound to the matrix, could be chased later into RNAs weakly bound to it. As the RNA-matrix binding weakens, the metabolic and structural properties of a given RNA change, e.g., sedimentation coefficients decrease, while the poly(A)+-RNA content and stability increase. The "adhesive" heterogeneity was found to be inherent in not only nuclear RNAs but also in cytoplasmic non-ribosomal RNAs, showing the same correlation, i.e., the tighter the RNA--protein complex, the higher the rate of RNA turnover. Cytoplasmic RNAs which differ in their adhesiveness may fulfil various intracellular functions, since polyribosomal mRNPs and informosomal mRNPs appear to be enriched in tightly and weakly bound RNA fractions, respectively. The interrelationships between nuclear and cytoplasmic RNAs are discussed.     

Changes in the mucosa of the duodenum and stomach as a result of experimental duodenal ulcers and vagotomy

By means of the transmissive and scanning electron microscopy methods and radioautography, structure of mucous membrane of the stomach and duodenum has been studied under experimentally induced duodenal ulcers before and after vagotomy during various time. The vagotomy results in accelerated healing of the ulcer defect. This is connected with an increased proliferative activity in the crypta cells, however, this is accompanied with deceleration of their differentiation. Under the duodenal ulcers the amount of chief and parietal cells increases in the gastric mucous membrane, this depends on gastrostasis produced by stenosis of the pylorus. At vagotomy the amount of the chief and parietal cells in the fundal glands of the mucous membrane decreases; this is accompanied with a lowered secretory activity.     

Competitive interaction of serotonin and the dye acridine orange with DNA

The interaction of serotonin and acridine orange dye with DNA isolated from bacterium Escherichia coli and the yeast Candida utilis has been analysed by spectrofluorimetric method. Using data on competitive binding to DNA of serotonin and acridine orange, known as DNA intercalator, a conclusion concerning the formation of intercalated complex between serotonin and DNA has been made. It is shown that for yeast DNA the constant of intercalated binding of serotonin is 3,5-fold smaller than for the bacterial one.     

Magnetic interaction of manganese with pheophytin anion-radical and chlorophyll cation-radical in reaction centers of the photosystem II

The influence of Mn on saturation curves of ESR spectra of Ph(-) and P(+)(680) at 1-200K in samples with different content of Mn has been studied. An analysis of these data and those on photoinduced changes of fluorescence yield of chlorophyll leads to the conclusion that the Mn-containing centre in Photosystem 2 is a cluster of 4 Mn atoms, two of which can be replaced by Mg(2+) or any other divalent metal. The distances between Mn Na Ph as well as between Mn and P(680) have been estimated.     

Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections

A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules.