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1.
Birendra K. Bhattacharya Mohan V. Chari Ross H. Durland Ganapathi R. Revankar 《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):45-63
Abstract A convenient synthesis of 1-(2-deoxy-β-D-erythro-pentofuranosyl)quinazoline-2,4(3H)-dione ( 6 ) has been accomplished. The structural conformation of ( 6 ) was derived by 2D NMR, COSY and NOESY experiments. Nucleoside ( 6 ) was incorporated into G-rich triplex forming oligonucleotides (TFOs) by solid-support, phosphoramidite method. The triplex forming capabilities of modified TFOs (S2, S3 and S4) has been evaluated in antiparallel motif with a target duplex (duplex-31) 5′d(GTCACTGGCCCTTCCTCCTTCCCGGTCTCAG)3′-5′d(CAGTGACCGGGAAGGAGGAAGGGCCAGAGT)3′ (D1) at pH 7.6. The parallel triplex formation of a shorter TFO (S6) containing Q has also been studied with a target duplex-11 (D2) at pH 5.0. 相似文献
2.
Michael P. Groziak Ronghui Lin William C. Stevens Linda L. Wotring Leroy B. Townsend J. Balzarini 《Nucleosides, nucleotides & nucleic acids》2013,32(5):1041-1057
Abstract ROESY and NOESY NMR spectroscopic analyses of the ribofuranosyl (1a), 2′-deoxyribofuranosyl (1b), and arabinofuranosyl (1c) derivatives of 6-formyluracil in (CD3)2SO and D2O solutions have established that each exclusive 7,05′-cyclic hemiacetal diastereomer of 1a,b and the major 7,O2′-cyclic hemiacetal diastereomer of 1c possess the 7R configuration. In addition, (7R)-1c has been shown to be thermodynamically more stable than (7S)-1c, contrary to our previous indication. A new, higher yielding synthetic route to 1a has been developed, 1b has been obtained for the first time in crystalline form, the route to 1c has been modified to better accommodate large scale preparations, and a new, fourth member of this class, 6-formylthymidine (1d), has been synthesized and its solution structures in (CD3)2SO, D2O, and CD3OD have been determined. Antitumor and antiviral evaluations of 1a-c have revealed no significant levels of activity. 相似文献
3.
Nazlaa Zaher Ioannis Nicolaou Vassilis J. Demopoulos 《Journal of enzyme inhibition and medicinal chemistry》2013,28(2):131-135
Abstract2,2-Dimethyl-4-hydroxy-4-androstene-3,17-dione (4) has been synthesized and has been shown to be a powerful competitive inhibitor of aromatase (Ki = 11.4nM). However, compound 4 does not cause time-dependent loss of enzyme activity, in contrast to the unmethylated parent compound, 4-OHA. 相似文献
4.
S. A. Ranade Anil Kumar Mamta Goswami Nuzhat Farooqui P. V. Sane 《Journal of biosciences》1997,22(4):457-464
Amaranths are an important group of plants and include grain, vegetable and ornamental types. Despite the economic importance
of the amaranths, there is very little information available about the extent and nature of genetic diversity present in the
genus
Amaranthus
at molecular level. We now report the randomly amplified polymorphic DNA (RAPD) profiles of different species of
Amaranthus
as well as different accessions of the species. These RAPD analyses have been carried out using 65 arbitrary sequence decamer
primers. From the RAPD data, an UPGMA dendrogram illustrating the inter-as well as intra-species relationships has been computed.
The putative hybrid origin of A.dubious
from
A. hybridus
and
A. spinosus
is also ruled out by the RAPD data. The trends of species relationships amongst the amaranths determined by RAPDs is consistent
with their cytogenetic and evolutionary relationships that have already been determined.
NBRI Communication No:464 (N.S.). 相似文献
5.
Summary. The two fMLF-OMe analogues For-Met-β3hAc6c-Phe-OMe (6) and For-Met-β2hAc6c-Phe-OMe (12) and their corresponding N-Boc derivatives 5 and 11 have been synthesized and their biological activity towards human neutrophils evaluated. The N-formyl peptides 6 and 12 exhibit good activity as chemoattractans and 12 is highly active in superoxide anion production. The preferred solution conformation of the two N-formyl derivatives has been discussed. 相似文献
6.
《Bioscience, biotechnology, and biochemistry》2013,77(11):2122-2128
Nineteen carotenoids were identified in extracts of petals of orange- and yellow-flowered cultivars of calendula (Calendula officinalis L.). Ten carotenoids were unique to orange-flowered cultivars. The UV–vis absorption maxima of these ten carotenoids were at longer wavelengths than that of flavoxanthin, the main carotenoid of calendula petals, and it is clear that these carotenoids are responsible for the orange color of the petals. Six carotenoids had a cis structure at C-5 (C-5′), and it is conceivable that these (5Z)-carotenoids are enzymatically isomerized at C-5 in a pathway that diverges from the main carotenoid biosynthesis pathway. Among them, (5Z,9Z)-lycopene (1), (5Z,9Z,5′Z,9′Z)-lycopene (3), (5′Z)-γ-carotene (4), and (5′Z,9′Z)-rubixanthin (5) has never before been identified. Additionally, (5Z,9Z,5′Z)-lycopene (2) has been reported only as a synthesized compound. 相似文献
7.
Pia N⊘ncgaard J⊘rgensen Margit L. Svendsen Claus Nielsen Jesper Wengel 《Nucleosides, nucleotides & nucleic acids》2013,32(3-5):921-924
Abstract The stereoselective synthesis of 3′-C-hydroxymethylthymidine (5) in five steps from thymidine has been accomplished and this nucleoside has been incorporated into oligodeoxynucleotides (ODNs) in different ways. 相似文献
8.
Romualdo Caputo Annalisa Guaragna Giovanni Palumbo Silvana Pedatella 《Nucleosides, nucleotides & nucleic acids》2013,32(4-5):651-652
Abstract 2-[[O-(p-Methoxybenzyl)-oxy]methyl]-5,6-dihydro-1,4-dithiin 1 is a versatile three carbon homologation reagent which has been conveniently used in the synthesis of enantiomerically pure modified nucleosides. 相似文献
9.
Charles A. Krauth Anita T. Shortnacy John K Montgomery John A. Secrist III 《Nucleosides, nucleotides & nucleic acids》2013,32(5-6):915-917
Abstract The antiviral activity of adenosine-N1-oxide (1) and a variety of substituted 1-(benzyloxy) adenosines (2) has been re-investigated and significant in vitro activity vs. Vaccinia virus has been shown. In vivo activity in mice has also been demonstrated. 相似文献
10.
【背景】近些年,越来越多的研究集中在红球菌上,很少有研究人员对现有文献进行全面回顾。【目的】为了探究国内外红球菌领域的研究热点、前沿和未来发展趋势,以便为后续研究人员提供全面直观的参考。【方法】对近10年发表在Web of Science的红球菌领域论文进行统计分析和文献计量分析。通过VOSviewer文献可视化软件绘制作者标签视图和关键词共现网络图。【结果】全球有关红球菌领域的发文量总体呈逐年上升趋势,发表期刊多为微生物学领域的专科期刊,中国和美国的文章发表数和引用数远超其他国家,红球菌的研究内容也主要集中在生物催化、生物降解和非核糖体肽合成酶等方面。【结论】红球菌在世界范围内越来越受到重视,并逐渐成为研究热点,国家和研究机构应继续加强合作,推动红球菌领域的继续发展。 相似文献
11.
David J. Hearn 《Brittonia》2007,59(4):308-327
Four new species and one new combination ofAdenia are presented, along with a vegetative key and diagnostic characters of the Madagascan species. Additional notes are provided
about unusual specimens and field observations.Adenia kigogoensis from Tanzania is shown to be distinct fromA. stenodactyla (its putative closest relative) andA. digitata based on anther connation and other floral traits. The remaining new taxa are from Madagascar.Adenia litoralis has been observed from one coastal locality in northern Madagascar. It is distinctive in fruit size and leaf form.Adenia metamorpha is the only Madagascan taxon with a narrow cylindrical trunk and large napiform tuber; it is also known from only one locality
in Madagascar in the Ankarana Reserve.Adenia mcdadiana is a robust liana with highly reduced glands and leaves that appear to be neotenic compared to its closest putative relative,A. sphaerocarpa. Finally, the position ofA. stylosa has been clarified. This species was once treated asA. firingalavensis var.stylosa, and prior to that asA. epigea var.stylosa, but molecular and morphological data suggest it is separate from these species. 相似文献
12.
David R. Armstrong John E. Davies Neil Feeder Elinor Lamb John J. Longridge Jeremy M. Rawson Ronald Snaith Andrew E. H. Wheatley 《Journal of molecular modeling》2000,6(2):234-247
Reaction of o-mercaptopyridine (o-MPH) and trithiocyanuric acid (TTCyH3) with one equivalent of BunLi in the presence of HMPA yields the mono-lithiated salts MPLi.HMPA (1) and TTCyH2Li.2HMPA (2) respectively, which have been characterised by NMR spectroscopy and X-ray crystallography. Reaction of three equivalents of BunLi with anhydrous TTCyH3 in THF yields the tri-lithiated species TTCyLi3.4THF (3). In all three compounds the lithium centres have N,S-bridged coordination modes. Whereas 1 is dimeric in the solid state, 2 has an unusual monomeric structure and 3, which is a very rare example of a structurally characterised tri-lithiated compound, has an unprecedented polymeric structure incorporating (NCSLi)
n
(n = 1, 2) rings. The structural diversities displayed by 1 and 2 have been probed, and thereby in part rationalised, by ab initio (6-31G*/RHF, 6-31G**/RHF and 6-31G*/MP2 levels) MO calculations on both their thio-keto and thiol isomers and on their uncomplexed and complexed lithiated derivatives. In particular, the optimised structures predict and reproduce the N,S-bridging coordination modes found for lithium and explain why structure 1 is dimeric whereas 2 is monomeric.Electronic Supplementary Material available. 相似文献
13.
Summary An azocasein assay has been developed for determination of alkaline protease in fermentation broth from a complex substrate containing ca. 50 g/l protein which to a high degree interferes with azocasein. Methods described in the literature have been found inaccurate as results deviate ca. 50% from true activity, so one of the methods is modified in order to eliminate interference. Proportionality between the relative azocasein concentration and the deviation from true activity is found. An azocasein concentration of 350 mg azocasein per ml sample gives satisfactory results with an accuracy of ±5%. Application of a standard addition method also improves the accuracy, but is laborious and less precise.Abbreviations
a
true enzyme activity
-
a
s
activity determined from standard curve
-
AU
Anson unit
-
c
A/T
relative azocasein concentration (mg azocasein per mg total protein)
-
r
ratio between measured and true enzyme activity
-
RD
relative deviation from true value (%)
-
RSD
relative standard deviation (%)
-
TCA
trichloroacetic acid 相似文献
14.
A. A. Ivanov V. I. Salyanov S. A. Strel’tsov N. A. Cherepanova E. S. Gromova A. L. Zhuze 《Russian Journal of Bioorganic Chemistry》2011,37(4):472-482
Five fluorescent symmetrical dimeric bisbenzimidazoles DB(n) containing four 2,6-substituted benzimidazole cores and differing in the length of the oligomethylene linker between two
bisbenzimidazole rings (n = 3, 4, 5, 7, 11) have been synthesized. The ability of the dimeric bisbenzimidazoles to form complexes with the double-stranded
DNA has been shown by spectral methods. Upon binding to the double-stranded DNA, DB(n) are localized in the narrow groove. The data on the inhibition of the DNA methyltransferase Dnmt3a by DB(n) indicate that dimeric bisbenzimidazoles DB(3) and DB(11) site-specifically bind to the oligonucleotide duplex. 相似文献
15.
Giorgio Forti 《Plant biosystems》2013,147(1-3):291-293
Abstract PARTIAL PURIFICATION OF DPN-KINASE FROM PEA LEAVES. — The presence of DPN-kinase has been demonstrated in pea leaves. The enzyme has been purified about 100 fold from this material. The possible significance of DPN-kinase and TPN-phosphatase (FORTI et Al., 1962) in the interconversion of pyridine nucleotides is discussed. 相似文献
16.
17.
Both ribofuranoside (3) and ribopyranoside (5) of 4-amino-5-cyano-6-methy lmercaptopyr-rolo[2,3-d]pyrimidine (analogs of toyocamycin) have been synthesized for the first time by the fusion procedure using bis-(p-nitrophenyl) hydrogen phosphate as catalyst. Evidence for the β-configuration has been provided by analyzing the NMR spectra and ORD curves. The tumor-inhibitory activity of 3 against EhrIich ascites carcinoma in mice has also been examined. 相似文献
18.
《Nucleosides, nucleotides & nucleic acids》2013,32(12):1849-1864
The formation of a disaccharide nucleoside (11) by O3′‐glycosylation of 5′‐O‐protected 2′‐deoxyadenosine or its N 6‐benzoylated derivative has been observed to be accompanied by anomerisation to the corresponding α‐anomeric product (12). The latter reaction can be explained by instability of the N‐glycosidic bond of purine 2′‐deoxynucleosides in the presence of Lewis acids. An independent study on the anomerisation of partly blocked 2′‐deoxyadenosine has been carried out. Additionally, transglycosylation has been utilized in the synthesis of 3′‐O‐β‐d‐ribofuranosyl‐2′‐deoxyadenosines and its α‐anomer. 相似文献
19.
Vishnumurthy R. Hegde Katherine L. Seley Xing Chen Stewart W. Schneller 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1905-1910
Abstract The chiral synthesis of (1S,3S,4S)-1-(3,4-dihydroxycyclopent-1-yl)-1H?thymine (carbocyclic 5′-nor thymidine, 4) has been achieved in 5 steps from (+)-(lR,4S)-4-hydroxy-2-cyclopenten-1-yl acetate (5) and N3?benzoylthymine. Compound 4 is viewed as a monomeric building block for poly-T-like oligomers. 相似文献
20.
Yingying Liu 《Plant Ecology & Diversity》2016,9(1):55-62
Background: Tropical rainforests represent the most species-rich and at the same time the most fragmented terrestrial biome on Earth. Fragmentation of tropical rainforests is having wide-ranging consequences for the maintenance of local species diversity and community assembly patterns.Aims: To examine floristic changes and changes in community phylogenetic structure in the forest fragment over the past five decades.Methods: A new taxonomic diversity algorithm (within-family diversity) was developed to assess floristic changes in the forest fragment. Community phylogenetic structure was then compared before and after fragmentation.Results: Taxonomic diversity changed greatly among families, with changes occurring randomly across the phylogeny. The forest fragment had higher phylogenetic diversity, higher mean pair-wise phylogenetic distance, but lower mean nearest-neighbour distance. The community phylogenetic structure has changed significantly from clustering to dispersion.Conclusions: High species turnover occurred in the forest fragment. While shade-tolerant species have been lost, and ruderal and alien species have been added, overall phylogenetic diversity has increased with species being more phylogenetically distant. Competitive exclusion, which was related to the relatively drier conditions in the forest after fragmentation, led the plant community phylogenetic structure to be more dispersed. 相似文献