共查询到20条相似文献,搜索用时 15 毫秒
1.
《Nucleosides, nucleotides & nucleic acids》2013,32(8-9):505-533
ABSTRACT A series of eleven heterodimers containing both a nucleoside analogue (d4U, d4T) and a non-nucleoside type inhibitor (Trovirdine analogue) were synthesized and evaluated for their ability to inhibit HIV replication. Unfortunately, the (N-3)d4U-Trovirdine conjugates (9a–e) and (N-3)d4T-Trovirdine conjugates (10a–f) were found to be inactive suggesting that the two individual inhibitor compounds do not bind simultaneously in their respective sites. 相似文献
2.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):791-795
Abstract CycloSal-d4TMP and two different bis(benzyl) phosphate triesters of the antivirally active nucleoside analog d4T were studied with regard to their chemical hydrolysis behavior at pH 7.3, in CEM/0 cell extracts, and their anti-HIV activity. In contrast to triesters 2–4, bis-(o-AB)-d4TMP 1 was found to be chemically exquisitely stable. All compounds led to the formation of d4TMP in cell extracts and all triesters achieved the TK-bypass. 相似文献
3.
《Journal of receptor and signal transduction research》2013,33(1-4):421-430
ABSTRACTThe coat colour in mammals is determined by the relative amounts of eumelanin (black/brown) and phaeomelanin (red/yellow), produced in melanocytes, which are controlled by melanocyte stimulating hormone receptor (MSH-R). Melanocyte stimulating hormone receptor is activated by α-melanocyte-stimulating hormone (α-MSH). Stimulated MSH-R activates adenylyl cyclase (AC), thereby increasing the amount of cyclic AMP in the cell, which activates the enzyme tyrosinase resulting in eumelanin synthesis. In this study the complete coding sequences of five alleles of the MSH-R gene found in Holstein, Red Holstein, Simmental, and Brown Swiss cattle were cloned into a mammalian expression vector and transfected into human embryonic kidney (HEK) 293 cells. The expressed receptors were analyzed for their ability to increase intracellular cAMP in response to stimulation by α-MSH. The recessive red allele (e) found in Red Holstein and Simmental and the dominant black allele (ED) found in Holstein were unresponsive to a wide range of α-MSH concentrations. Two alleles from Brown Swiss (Ed1, Ed2) and one allele found in the Simmental breed (ef) responded to stimulation by α-MSH in a dose-dependent manner. When compared to Ed1 and Ed2, the cells transfected with the ef MSH-R allele, however, reached the corresponding intracellular cAMP concentrations at a 10-fold higher concentration of α-MSH. In conjunction with the mode of inheritance of coat colour, the results indicate that the e MSH-R allele is a non-functional receptor, ED is constitutively activated receptor, and Ed1 and Ed2 are hormonally activated receptors. The delay in ef MSH-R response may explain the similarity between the e and ef phenotypes. 相似文献
4.
Jingling Shao Rongwei Shi Cheng Wang Xiaolei Zhu Xiaohua Lu 《Journal of molecular modeling》2010,16(5):939-950
The geometrical structures, potential energy surface, stability, and bonding character of low-energy isomers of planar C3B3 were systematically explored and investigated at the B3LYP/6-311+G(d)// CCSD(T)/6-311+G(d) level for the first time. A large
number of planar structures for low-energy isomers of C3B3 are located and reported. In particular, isomers 1 (Cs,2A’) and 2 (Cs,2A’), with a belt-like structure corresponding to the lowest-energy structures of planar C3B3, are revealed. Based on molecular orbital (MO) and natural bond orbital (NBO) analyses, delocalized σ MOs, multi-centered
σ MOs, and delocalized π MOs play an important role in stabilizing the structures of low-energy isomers of C3B3. It is interesting to note from isomerization analysis that the interconversion of isomers 2 and 7 can be realized through two isomerization channels. The results demonstrate that isomers 1, 2, 3, 4, 7, 9, 12, 17, 19, and 20 of C3B3 are stable both thermodynamically and kinetically at the B3LYP/ 6-311+G(d)//CCSD(T)/ 6-311+G(d) level, and that they are
observable in the laboratory, which is helpful for future experimental studies of C3B3. 相似文献
5.
目的:探讨一种声弹性成像定量分析方法用于评价深静脉血栓(DVT)患者血栓进展的情况。方法:经处理得12条大隐静脉标本,采用声弹性成像技术分别在1d、3d、6d、9d采集静脉标本中血凝块声弹性图像;应用等硬度区域面积测量技术(AMEHR)进行处理,计算血凝块区域在静脉标本中所占的比例,并进行数据分析。结果:经由AMEHR技术分析,在1d、3d、6d、9d静脉标本中,血凝块区所占比例分别为46.72%±12.16%,71.93%±7.24%,82.17%±5.17%,91.92%±3.69%。随着血栓时间的增加,血凝块区域所占比例逐渐增加,且差异有统计学意义(P0.05);随着时间的进展,血凝块增长的速率逐渐降低(1-3d:25.21%,3-6d:10.24%,6-9d:9.75%)。结论:AMEHR技术对血栓形成时间的评估上有一定的应用价值,有望为评估血栓形成时间提供参考。 相似文献
6.
[目的] 研究核桃壳提取液(walnut shell extracts,WSE)对单针藻Monoraphidium sp.QLZ-3生长和油脂积累的影响。[方法] 向BG-11培养基中添加不同量的WSE(培养基中保留有BG-11中全部营养成分)。[结果] 结果显示,当BG-11培养基中的WSE含量为40%时,单针藻的生物量产率及油脂产率达到(534.70±4.07)mg/(L·d)和(296.35±15.36)mg/(L·d),相比对照组分别提高了的14.82%和33.50%,蛋白质和碳水化合物含量分别有不同程度的上调和下调。与对照组相比,微藻中谷胱甘肽(glutathione,GSH)和超氧化物歧化酶(superoxide dismutase,SOD)含量与活性均上调。此外,WSE作用下,微藻对多酚的移除达到84.37%,同时上调了核酮糖1,5-二磷酸羧化酶基因(ribulose 1,5-bisphosphate carboxylase/oxygenase,rbcL)和乙酰辅酶A羧化酶(acetyl coenzyme A carboxylase,accD)基因的表达量。[结论] 研究表明,WSE联合BG-11可以提高微藻的生物量产率和油脂产率,降低微藻培养的原料成本,为核桃壳的资源化利用及微藻的工业化生产提供了一定的技术支撑。 相似文献
7.
N. Escaja E. Pedroso S. A. Salisbury C. Gonzàlez 《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):1601-1602
Abstract The refined NMR structures of the cyclic octamers d?pATTCATTC?1 and d?pGCTCGCTT?2 are consistent with the reported Crystallographic data of 1 and the linear heptamer d(GCATGCT), respectively. The NMR study of four new cyclic octamers shows that in all cases a dimeric bi-loop structure is observed in equilibrium with a monomeric form. 相似文献
8.
Abstract The base pairing ambiguity of 7-deaza-2′-deoxyinosine (c7Id, 2) was studied and was found to be the same as that of 2′-deoxyinosine. The duplex stability decreases in the order [d(c7I-C) > d(c7I-A) > d(c7I-T) > d(c7I-G)]. Modified nucleosides were used to probe the various base pair motifs which were the same for dl and c7Id. The 7-deazapurine nucleoside (2) is extremely stable against acid or base. As oligonucleotides can be prepared using phosphoramidite chemistry and DNA is accessible by enzymic polymerisation of the triphosphate of 2, the latter can be used as an universal nucleoside for the sequencing of DNA by chemical degradation and is otherwise a facile substitute of 2′-deoxyinosine when stability in acidic or alkaline solution is required. 相似文献
9.
L. De Napoli A. Messere D. Montesarchio G. Piccialli C. Santacroce 《Nucleosides, nucleotides & nucleic acids》2013,32(9):981-992
Abstract 2′,3′-dideoxy- and 2′,3′-dideoxy-2′,3′-didehydrocy-tidine (d2C and d4C) have been synthesized in good yields from 2′-deoxyuridine via dichlorinated derivatives 7a-b. The same synthetic strategy was used in the synthesis of d2CMe and d4CMe from thymidine. Following this method the evaluable 3′-chloro-2′-deoxycytidine derivatives 9-12 can easily be obtained. 相似文献
10.
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
11.
Toshio Shida Mitsuaki Suda Junichi Sekiguchi 《Nucleosides, nucleotides & nucleic acids》2013,32(1-3):575-584
Abstract To clarify the reasons for the high fidelity of repetitive telomeric sequences, a series of d(TTXGGG)4 (X: A, G, C, and T) were synthesized and characterized by UV absorption, CD, chemical modification, and resistance to nucleases. d(TTCGGG)4, which is lacking in nature, has similar structural stability and resistance to nucleases, compared with d(TTAGGG)4, which is widely present at the telomeres of many organisms. d(TTGGGG)4 is the most stable as a result of formation of the four G-quartet layers in the presence of potassium ion. 相似文献
12.
目的:研究Ghrelin对大鼠脑出血后脑水肿及脑组织中基质金属蛋白酶-9(MMP-9)表达的影响。方法:选取雄性SD大鼠80只,随机分为对照组(NC组)20只、假手术组(SHAM组)20只、脑出血组(ICH组)20只、Ghrelin治疗组(Ghrelin组)20只。利用自体动脉血注入法建立大鼠脑出血模型;Ghrelin组于建立脑出血模型后经股静脉注射Ghrelin 10 nmol/Kg·d。分别于12 h、24 h、3d、5 d、7 d时间点根据Berderson评分法评估各组大鼠神经系统功能;利用干湿重法测定各组大鼠脑组织含水量;利用蛋白质免疫印迹法(WB)检测脑组织中MMP-9表达情况。结果:在12 h、24 h、3 d、5 d、7 d,ICH组、Ghrelin组大鼠Berderson评分及脑组织含水量高于NC组、SHAM组(P0.05);在5 d、7 d,ICH组大鼠Berderson评分及脑组织含水量高于Ghrelin组(P0.05)。WB结果表明在12 h、24 h、3 d、5 d、7 d,ICH组大鼠脑组织中MMP-9的表达均高于NC组、SHAM组(P0.05);Ghrelin组MMP-9的表达在12 h、24 h、3 d高于NC组、SHAM组(P0.05),在5 d、7 d,与NC组、SHAM组无明显差异(P0.05);在5 d、7 d,ICH组MMP-9表达高于Ghrelin组(P0.05)。结论:在本研究中,Ghrelin可以在5 d后降低脑出血大鼠脑组织中MMP-9的表达程度,从而减轻脑水肿,改善脑出血大鼠神经功能。 相似文献
13.
Zhongshan Gao Eric W van de Weg Catarina I Matos Paul Arens Suzanne THP Bolhaar Andre C Knulst Yinghui Li Karin Hoffmann-Sommergruber Luud JWJ Gilissen 《BMC plant biology》2008,8(1):116
Background
Mal d 1 is a major apple allergen causing food allergic symptoms of the oral allergy syndrome (OAS) in birch-pollen sensitised patients. The Mal d 1 gene family is known to have at least 7 intron-containing and 11 intronless members that have been mapped in clusters on three linkage groups. In this study, the allelic diversity of the seven intron-containing Mal d 1 genes was assessed among a set of apple cultivars by sequencing or indirectly through pedigree genotyping. Protein variant constitutions were subsequently compared with Skin Prick Test (SPT) responses to study the association of deduced protein variants with allergenicity in a set of 14 cultivars. 相似文献14.
This work presents a computational study on the molecular structure and tautomeric equilibria of a novel Schiff base L derived from pyridoxal (PL) and o-phenylenediamine by using the density functional method B3LYP with basis sets 6-31 G(d,p), 6-31++G(d,p), 6-311 G(d,p) and
6-311++G(d,p). The optimized geometrical parameters obtained by B3LYP/6-31 G(d,p) method showed the best agreement with the
experimental values. Tautomeric stability study of L inferred that the enolimine form is more stable than its ketoenamine form in both gas phase and solution. However, protonation
of the pyridoxal nitrogen atom (LH) have accelerated the formation of ketoenamine form, and therefore, both ketoenamine and enolimine forms could be present
in acidic media. 相似文献
15.
Birendra K. Bhattacharya Rodrigo V. Devivar Ganapathi R. Revankar 《Nucleosides, nucleotides & nucleic acids》2013,32(6):1269-1287
Abstract A convenient synthesis of N1-methyl-2′-deoxy-ψ-uridine (ψ-thymidine, ψT, 7a) has been accomplished in good yield. The structural conformation of 7a was derived by 2D NMR and 1D NOE experiments. The nucleoside 7a has been incorporated into G-rich triplex forming oligonucleotides (TFOs) by solid-support, phosphoramidite method. The triplex forming capabilities of the modified TFOs (S4, S5 and S6) containing ψT has been evaluated in antiparallel motif with a target duplex (duplex-31) 5′d(CTGAGACCGGGAAGGAGGAAGGGCCAGTGAC)3′-5′d(GACTCTGGCCCTTCCTCCTTCCCGGTCACTG)3′(D1) at pH 7.6. The triplex formation of modified homopyrimidine-oligomers (S1, S2 and S3) has also been studied in parallel motif with a duplex-10 (A10:T10) at pH 7.0. 相似文献
16.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1309-1311
Abstract An efficient synthesis of adenosine bearing pyrrolepolyamide 1 was achieved by coupling of 3 with 2. The CD spectra obtained at several [ligand ]/[duplex] ratios allowed verification of the formation complex of the DNA duplex [d(CGCAAATTGGC)/d(GCCAATTTGCG)] with 1. 相似文献
17.
Andrea Giacometti 《Journal of biomolecular structure & dynamics》2013,31(5):671-676
Abstract The nucleic acid triplexes poly d(T)·poly d(A)·poly d(T), poly (U)·poly (A)·poly (U), and poly (I)·poly (A)·poly (I) display a sort of continuity between each other. However, their morphologies present their own individuality which, considering those of their parent duplexes, are quite unexpected. This comparison helps to understand triplex structure-function relationship. While helical parameters are functions of the sugar pucker, low values of WC and Hoogsteen base-pair propellers is commonplace for triplexes and the Hoogsteen base-pair geometry monitors the effects of the interstrand phosphates charge-charge repulsion. Synopsis The nucleic acid triplexes poly d(T)·poly d(A)·poly d(T), poly(U)·poly(A)·poly(U), and poly (I)·poly (A)·poly (I) present distinct morphologies. Considering those of their parent duplexes, they are also quite unexpected. 相似文献
18.
Abstract The syntheses of 2′,3′-didehydro-2′,3′-dideoxyisoinosine (d4isoI, 4) as well as 7-deaza-2′,3′-didehydro-2′,3′-dideoxyisoinosine (d4c7isoI, 5) are described. Compounds 4 and 5 show both strong fluorescence. Compound 4 is oxidized by xanthine oxidase to give the corresponding xanthine 2′,3′-dideoxy-2′,3′-didehydronucleosides. A preparative chemo-enzymatic synthesis of 2′-deoxyxanthosine (3) is described. 相似文献
19.
Abstract The effect of methylation of the 0–6 position of guanine in short segments of double helical DNA has been investigated by molecular mechanical simulations on the sequences d(CGCGCG)2, d(CGC+AFs-OMG+AF0-CG)2, d(CGT+AFs-OMG+AF0-CG)2, d(CGC+AFs-OMC+AF0-CG/(CGCGCG), d(CGC+AFs-OMG+AF0-CG/d(CGTGCG), d(CGCGAATTCGCG)2 and d(CGCGAATTC+AFs-OMG+AF0-CG)2. Guanines methylated at the 0–6 position are found to form hydrogen bonds of roughly equal strength to cytosine and thymine. The optimum structure of these modified base pairs are not dramatically different from normal GC pairs, but both involve some bifurcation of the proton donors of cytosine (4NH2) or thymine (3NH) between the guanine N3 and O6 groups. 相似文献
20.
Marie Zarevúcka Martin Rejzek Milan Pavlík Zdeněk Wimmer Jan Zima Marie-Dominique Legoy 《Biotechnology letters》1994,16(8):807-812
Summary The racemic cis and trans isomers 1a and 1b of 2-(4-methoxybenzyl)-1-cyclohexanol were subjects of an enzyme mediated resolution via esterification in organic solvents, in which the chiral esters 2a and 2b of the corresponding alcohols 4a and 4b, and the chiral alcohols 3a and 3b were obtained. The chemical yield and enantioselectivity of this enzymatic reaction have been found to depend mainly on (a) the structure of the substrate (cis or trans), (b) temperature, (c) the nature of the enzyme selected, and (d) the nature of the solvent. 相似文献