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21.
Andrey A. Rosenkranz Sergey V. Yachmenev David A. Jans Natalya V. Serebryakova Vitaly I. Murav''ev Reiner Peters Alexander S. Sobolev 《Experimental cell research》1992,199(2):323-329
A soluble construct consisting of a plasmid carrying the gene of the SV40 large T-antigen and an insulin-poly-L-lysine conjugate is able to selectively transfect PLC/PRF/5 human hepatoma cells which possess insulin receptors. Transfection can be efficiently competed by excess free insulin. To examine intracellular transport of the construct, it was fluorescently labeled and its accumulation on and in cells visualized by video-enhanced microscopy and quantitative confocal laser scanning microscopy. After 2 h at 37 degrees C, the labeled construct was found predominantly in intracellular acidic compartments, with a substantial portion of fluorescence localized both near and in the cell nucleus. Binding, endocytosis, and nuclear localization of the labeled conjugate could all be competed by excess free insulin, thus indicating that entry of the conjugate into cells was specifically mediated by the insulin receptor. 相似文献
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Dr. Michael A. Belenky Vladimir K. Chetverukhin Andrey L. Polenov 《Cell and tissue research》1979,204(2):333-342
The distribution of monoaminergic structures was studied in the proximal neurosecretory contact region and neurohypophysis of the lamprey by light and electron microscopic radioautography. Only weak radioautographic reactions were found in the proximal neurosecretory contact region 1 h after injection of 3H-dopamine. High-resolution radioautography revealed some labeled neurosecretory terminals mainly in contact with the basement membrane of the connective tissue layer separating the proximal neurosecretory contact region from the hypophysial pars distalis. The number of silver grains as well as the number of neurosecretory terminals marked by the presence of labeled dopamine was much higher in the neurohypophysis of the same species. In the latter, labeled neurosecretory terminals were found in contact with the connective tissue layer containing blood vessels of the general circulation. Some neurosecretory terminals make synaptoid contacts with tanycyte perikarya and their basal processes. According to their ultrastructure and the size of their granules, the labeled neurosecretory terminals are identical with the B type terminals described in both neurohemal regions (transmission electron microscopy). No labeled neurosecretory terminals were observed in the proximal neurosecretory contact region and the neurohypophysis of lampreys treated with the serotonin precursor, 3H-5-hydroxytryptophan. 相似文献
24.
A cytological study of the Cedrus libani mature pollen from 3 culture areas (Italy, France, USSR) has shown that 69-71% of pollen grains have two-celled protallium and antheridial cell. About 5% of pollen grains are characterized by accelerated of delayed development, otherwise apparently normal. The pollen sterility (up to 30% of grains) is due to the abortive spore development. Anomalous cenocyte and multinuclear pollen grains were found thus suggesting that multicellular haploid structures capable of further growth and development may arise in the course of natural anther development. 相似文献
25.
Luiz Henrique Soares de Andrade Wilson Max Almeida Monteiro de Moraes Eduardo Hiroshi Matsuo Junior Elizabeth de Orleans Carvalho de Moura Hanna Karen Moreira Antunes Jairo Montemor Ednei Luiz Antonio Danilo Sales Bocalini Andrey Jorge Serra Paulo José Ferreira Tucci Patricia Chakur Brum Alessandra Medeiros 《Molecular and cellular biochemistry》2015,402(1-2):193-202
26.
Andrey M. Grishin Eunice Ajamian Linhua Zhang Isabelle Rouiller Mihnea Bostina Miroslaw Cygler 《The Journal of biological chemistry》2012,287(45):37986-37996
Microbial anaerobic and so-called hybrid pathways for degradation of aromatic compounds contain β-oxidation-like steps. These reactions convert the product of the opening of the aromatic ring to common metabolites. The hybrid phenylacetate degradation pathway is encoded in Escherichia coli by the paa operon containing genes for 10 enzymes. Previously, we have analyzed protein-protein interactions among the enzymes catalyzing the initial oxidation steps in the paa pathway (Grishin, A. M., Ajamian, E., Tao, L., Zhang, L., Menard, R., and Cygler, M. (2011) J. Biol. Chem. 286, 10735–10743). Here we report characterization of interactions between the remaining enzymes of this pathway and show another stable complex, PaaFG, an enoyl-CoA hydratase and enoyl-Coa isomerase, both belonging to the crotonase superfamily. These steps are biochemically similar to the well studied fatty acid β-oxidation, which can be catalyzed by individual monofunctional enzymes, multifunctional enzymes comprising several domains, or enzymatic complexes such as the bacterial fatty acid β-oxidation complex. We have determined the structure of the PaaFG complex and determined that although individually PaaF and PaaG are similar to enzymes from the fatty acid β-oxidation pathway, the structure of the complex is dissimilar from bacterial fatty acid β-oxidation complexes. The PaaFG complex has a four-layered structure composed of homotrimeric discs of PaaF and PaaG. The active sites of PaaF and PaaG are adapted to accept the intermediary components of the Paa pathway, different from those of the fatty acid β-oxidation. The association of PaaF and PaaG into a stable complex might serve to speed up the steps of the pathway following the conversion of phenylacetyl-CoA to a toxic and unstable epoxide-CoA by PaaABCE monooxygenase. 相似文献
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The Middle Longcraig Limestone (late Visean) at Catcraig, Scotland, is densely covered with large (about 1 m in diameter) hollows, which are surrounded by numerous fossilized roots. The latter represent the positions of tree-sized plants belonging to a fossil forest. This paper aims to reconstruct its ecology based on paleosol properties, size and spatial distribution of root-casts, rooting system morphology and characteristics of coalified plant remnants. The obtained data are consistent with the supposition that the Visean peat wetland forest of Catcraig represents a Cordaitalean dominated community composed of mono-sized, most probably, even-aged giant trees. The peaty paleosol (Histosol) contains pyrite and siderite, indicating reducing and acidic conditions, whilst the abundant presence of gypsum testifies periods of elevated salinity. The adaptation of trees to such conditions is supported by morphologically evident large root mass (typically more than 1000 individual roots per cast). Good preservation of plant tissues in peat, in addition to other paleosol and rooting system characteristics allow us to conclude that the trees occupied seacoast settings or lagoons, which were not permanently flooded. 相似文献
29.
Henrik Gislason Jeremy Collie Brian R. MacKenzie Anders Nielsen Maria de Fatima Borges Teresa Bottari Corina Chaves Andrey V. Dolgov Jakov Dul
i Daniel Duplisea Heino O. Fock Didier Gascuel Luís Gil de Sola Jan Geert Hiddink Remment ter Hofstede Igor Isajlovi Jnas Pll Jonasson Ole Jrgensen Kristjn Kristinsson Gudrun Marteinsdottir Hicham Masski Sanja Mati‐Skoko Mark R. Payne Melita Peharda Jakup Reinert Jn Slmundsson Cristina Silva Lilja Stefansdottir Francisco Velasco Nedo Vrgo
《Global Ecology and Biogeography》2020,29(5):842-856
30.
Alexander N. Prutkov Andrey V. Matveev Lyubov E. Grebenkina Mikhail G. Akimov Yulia V. Berezovskaya 《Nucleosides, nucleotides & nucleic acids》2020,39(7):943-963
AbstractSome 5-substituted ribavirin analogues have a high antiviral and anticancer activity, but their mechanisms of action are obviously not the same as their parent compound. The SAR studies performed on 3 (5)-substituted 1,2,4-triazole nucleosides have shown a high dependency between the structure of the 3 (5)-substituent and the level of antiviral/anticancer activity. The most active substances of the row contain coplanar with the 1,2,4-triazole ring aromatic substituent which is connected by a rigid ethynyl bond. However, the compounds with the trans-vinyl linker also had antiviral activity. We decided to study the antitumor activity of ribavirin analogues with alkyl/aryl vinyl substituents in the 5th position of the 1,2,4-triazole ring. Protected nucleoside analogues with various 5-alkylvinyl substituents were obtained by Horner-Wadsworth-Emmons reaction from the common precursor and converted to the nucleosides. Arylvinyl nucleosides were synthesised according the reported procedures. All compounds did not show significant antiproliferative activity on several tumour cell lines. Coplanar aromatic motif in the 5-substituent for the anticancer activity manifestation was confirmed. 相似文献