Results 1 - 10 of 7656
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[en] This patent describes a radioactively labeled protein comprising a protein, and a radioactive nucloeside or nucleotide, wherein a radioactive moiety is present in the nucleoside or nucleotide. The protein is convalently linked to the nucleoside or nucleotide
[en] A new ceramid (2S*, 3S*, 4E, 8E)-2N-(hexadecanoyl)-4 (E), 8 (E)-docosadiene-1, 3-diol (1), along with the previously identified one (2S*, 3S*, 4E, 8E)-2N-(tetradecanoyl)-4 (E), 8 (E)-icosadiene-1, 3-diol (2), and the dihydroxy steroid, 24-methyl-cholest-5 (E), 22 (E)-dien-3?,7?-diol (3) were identified from the Red Sea black coral Antipathies dichotoma. Extensive spectroscopic data 1D and 2D- NMR, UV, IR and MS were the bases for structure elucidation of all isolated metabolites. The spectral values for compound 3 are reported here for the first time. All compounds have been estimated toward their cytotoxicity, against several cancer cell lines; HepG2, WI 38, VERO and MCF-7. They showed strong to moderate cytotoxic activities. Compounds 1 and 2 displayed strong antiproliferative activities against HepG2 and MCF-7 cell lines. 3 displayed almost weak activity towards all investigated cell lines. (author)
[en] Cyclo-nucleosides are complex DNA damages implying both bases and sugar residues. They are generated by free radicals, in particular by the effect of ionizing radiations, and are not easily covered by cellular mechanisms. Using a protein trapping technique on probes containing these injuries, the negative influence of cyclo-nucleosides on the recognition of its target sequence by a DREF transcription factor and on the interactions of PARP1 with DNA have been identified. Interactions between Fpg bacterial glycosylase and cyclo-nucleosides have been analysed and it has been found that this enzyme has an affinity for them, without excision activity. Finally, a Thermococcus gammatolerans radiation resistant archae has been studied: the formation of simple and complex oxidation injuries at strong radiation doses has been measured and the action mechanism of two new glycosylases has been explained. (author)
[fr]Les cyclonucleosides sont des dommages complexes de l'ADN qui impliquent a la fois la base et le residu de sucre. Ils sont generes via les radicaux libres, notamment sous l'effet des rayonnements ionisants, et ils sont difficilement pris en charge par les mecanismes cellulaires. En utilisant une technique de piegeage de proteines sur les sondes comportant ces lesions, nous avons identifie l'influence negative des cyclonucleosides sur la reconnaissance de sa sequence cible par un facteur de transcription DREF, et sur les interactions de PARP1 avec l'ADN. Nous avons egalement analyse les interactions entre une glycosylase bacterienne Fpg et les cyclonucleosides et trouve que cette enzyme possede une affinite pour eux, sans activite d'excision. Enfin, une archee radioresistante Thermococcus gammatolerans a ete etudiee: la formation des lesions d'oxydations simples et complexes a forte dose d'irradiation a ete evaluee, et le mecanisme d'action de deux nouvelles glycosylases a ete elucide
[en] Structural features and biological properties of natural disaccharide nucleosides and related compounds are considered. The main methods for the synthesis of these compounds are described and their advantages and disadvantages are discussed. These methods include condensations of a protected disaccharide with a heterocyclic base or of a protected nucleoside with an activated monosaccharide.
[en] This paper describes the racemic and stereoselective synthetic route for a novel 4'α-phenyl and 6'α-methyl doubly branched carbocyclic nucleosides from an acyclic 2-hydroxy acetophenone. The installation of phenyl group at the 4'-position of carbocyclic nucleoside was successfully accomplished via a sequential [3,3]- sigmatropic rearrangement. The stereoselective introduction of a methyl group in the 6'α-position was accomplished by Felkin-Anh controlled alkylation. Bis-vinyl 11 compound was successfully cyclized using a Grubbs' catalyst II to desired carbocycles. The natural bases (adenine and cytosine) were efficiently coupled using a Pd(0) catalyst. Although all the synthesized compounds were examined for their activity against several viruses such as HIV-1, HSV-1, HSV-2 and HCMV, only cytosine analogues 17 exhibited weak antiviral activity against HCMV
[en] An efficient synthetic route for preparing novel 4'α-C phenyl branched carbocyclic nucleoside is described. The installation of phenyl group at the 4'-position of carbocyclic nucleoside was successfully accomplished via a sequential [3,3]-sigmatropic rearrangement and ring-closing metathesis (RCM) beginning from simple ketone such as 2-hydroxy acetophenone
[en] 3'-O-Acetylthymidine was converted to the β-acetoxy aldehyde using a modified Swern oxidation procedure. The crude product was reduced with sodium borodeuteride to give, after chromatography, [5'-2H]-3'-O-acetylthymidine in 68% overall yield. The extent of deuterium incorporation was >95% as judged by 1H NMR spectroscopy. (author)
[en] The known methods for the synthesis of 2'-functionalised nucleosides, oligonucleotides and their conjugates are systematised. The applications of 2'-modified nucleosides and oligonucleotides are discussed.