共查询到20条相似文献,搜索用时 15 毫秒
1.
YU SWETT T. 《动物分类学报》1966,(2)
The present paper deals with 3 new "Capritermes typus" termites belonging toMirocapritermes, Procapritermes and Homallotermes respectively. Holotypes, morphotypes,paratypes and thier duplications are deposited in Huanan Tropical Crops College, Tan-hsien, Hainan Is., China. 相似文献
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《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):435-447
ABSTRACT A method has been found for the regioselective alkylation of the nitrogen at the 1-position of 2′-deoxyguanosine. This consists in the reaction, in tetrahydrofuran solution, of a fully protected form of dG, namely the 3′5′-O-bis(tert-butyldimethylsilyl)-N 2-dimethylaminomethylene derivative, with an alkyl halide in the presence of cesium carbonate. The yields of these previously unavailable derivatives of 2′-deoxyguanosine range from good to excellent. Confirmation of the structure of these substances comes from a comparison of their spectroscopic properties with those of the known 1-methyl homologue. In particular, the UV spectra of these new derivatives and the known 1-methyl homologue are essentially identical. 相似文献
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《古生物学报》1988,(2)
The 2nd Congress of the Paleobotanical Society of Palaeontological Society and the Paleobolanical symposium (1987) held from November 24th to 27th at Nanjing, Jiangsu. Present at the meeting were 86 Chinese paleobotanists and several students from research institutes, universities, colleges, natural historical museums and geological, coal- and petroleum-prospecting parties. 相似文献
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《Nucleosides, nucleotides & nucleic acids》2013,32(4-7):1243-1246
In order to clarify whether L-enantiomers of natural 2′-deoxyribonucleoside 5′-triphosphates (dNTPs) are recognized by human telomerase, a quantitative telomerase assay based on the ‘stretch PCR’ method was developed and used for kinetic analysis. Among the four L-dNTPs, L-dTTP and L-dGTP inhibited telomerase activity and the others showed slight or no inhibitory effect. Lineweaver-Burk plot analysis showed that the inhibition mode L-dGTP was competitive with dGTP. 相似文献
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Abstract A novel approach to 2′-O-alkylpyrimidine nucleosides involving a 3′- hydroxyl assisted intramolecular delivery of a divalent metal alkoxide leads to a regiospecific opening of the anhydropyrimidine linkage at the 2′-position. Thus, reaction of 5′-protected 2,2′-anhydrouridine with magnesium or calcium alkoxides in DMF affords exclusively the corresponding 2′-O-alkyluridines in reasonable yields. 相似文献
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Abstract Two nucleoside analogs were synthesized to test the ribose conformational and electronic effects on phosphate hydrolysis at the 3′ position. It was found that under alkaline conditions, a 2′-fluoro-nucleoside (C3′-endo) resulted in a phosphate degradation that was ten times faster than the 2′-deoxynucleoside analog (C2′-endo). In addition to kinetic differences, product distributions will be presented. 相似文献
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《Nucleosides, nucleotides & nucleic acids》2013,32(5-7):577-580
Starting from 2-C-methyl-ribonolactone, 1,2,3,5-tetra-O-acetyl-2-C-methyl-4-thioribofuranose was synthesized and condensed with heterocyclic bases to afford 2′-C-methyl-4′-thioribonucleosides. 相似文献
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《Nucleosides, nucleotides & nucleic acids》2013,32(5-7):691-694
C8-Arylamine-dG adducts were converted into their corresponding 5′-O-DMTr-3′-O-phosphoramidite-C8-arylamine-dG derivatives. These compounds were used for the automated synthesis of site-specifically modified oligonucleotides. The oligonucleotides were studied for their CD properties, Tm values, and their effects on primer extension assays using human DNA-polymerase β. 相似文献
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《Nucleosides, nucleotides & nucleic acids》2013,32(4-7):1225-1228
The structures of the bound 13C/2H double-labelled 2′(R/S), 5′(R/S)-2H2-1′,2′,3′,4′,5′-13C5-2′-deoxyadenosine and the corresponding 2′-deoxycytidine moieties in the complexes with human deoxycytidine kinase (dCK) have been characterized for the first time by the solution NMR spectroscopy, using Transferred Dipole-Dipole Cross-correlated Relaxation and Transferred nOe experiments. It has been shown that the ligand adopts a South-type sugar conformation when bound to dCK. 相似文献
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《Nucleosides, nucleotides & nucleic acids》2013,32(8):1449-1461
We report the synthesis of the triphosphate of 5-methyl 4-N-[6-(p-bromobenzamido)hex-1-yl]-2′-O-deoxycytidine 3A . We also analyzed the formation of intramolecular H-bonds of 5-methyl 4-N-{n-[6-(p-bromobenzamido) caproyl amino]alk-1-yl}-2′-deoxycytidine compounds, and confirmed their presence by 1H-NMR studies. In vitro DNA labeling with modified nucleotides is preliminarily evaluated. 相似文献
12.
《Nucleosides, nucleotides & nucleic acids》2013,32(4-7):689-693
Fluorinated analogs of 2′- and 3′-deoxy-5′-methylthioadenosine 1–4 caused irreversible inactivation of AdoHcy hydrolase. Based on the ESI-Mass spectra analysis of the inactivated enzyme with the fluorinated analog 1 a mechanism of inactivation is proposed. 相似文献
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J. E. Pritchard 《CMAJ》1931,24(5):689-692
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《Nucleosides, nucleotides & nucleic acids》2013,32(11-12):891-901
ABSTRACT Synthesis and antiviral activity of several new 8-substituted carbocyclic analogs of D-2′,3′-dideoxyadenosine are described. The new 8-substituted analogs were synthesized via lithiation of carbocyclic 2′,3′-dideoxy adenosine followed by quenching with electrophiles. This methodology allows for a divergent synthesis of a variety of 8-substituted analogs from carbocyclic 2′,3′-dideoxyadenosine in high yields. 8-Methyl and 8-halogenated carbocyclic 2′,3′-dideoxyadenosine analogs showed 6–25 fold more activity against hepatitis B virus than the unsubstituted carbocyclic D-2′,3′-dideoxyadenosine. 相似文献
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The temperature coefficient of the action of β-rays from radium upon the egg of Nereis lies between 1.1 and 1.2. This is of a magnitude characteristic of photochemical reactions. 相似文献
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