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排序方式: 共有825条查询结果,搜索用时 406 毫秒
251.
Mujahid Yusufi Sanjeev Banerjee Momin Mohammad Sandhya Khatal K. Venkateswara Swamy Ejazuddin M. Khan Amro Aboukameel Fazlul H. Sarkar Subhash Padhye 《Bioorganic & medicinal chemistry letters》2013,23(10):3101-3104
Thymoquinone (TQ), isolated from the seeds of Nigella sativa, show moderate efficacy against pancreatic cancer. In the present work we report synthesis and characterization of novel TQ analogs appended with gallate and fluorogallate pharmacophores and evaluation of their effects against pancreatic cancer cell lines for cell viability and induction of apoptosis. The efficacy of the analogs alone or in combination with Gemcitabine was assessed in vitro. LC–MS spectra of ATQTHB and ATQTFB showed major peaks corresponding to expected M+1 fragment at 316.34 and 322.34 respectively. Molecular docking studies revealed good fit for these analogs in the COX-2 protein cavity with better binding energies compared to parent TQ compound. Present TQ analogs exhibit superior anti-proliferative activity, excellent chemo-sensitizing activity against pancreatic cancer in vitro and in combination with Gemcitabine. 相似文献
252.
Atul Kondaskar Shilpi Kondaskar James C. Fishbein Brandon A. Carter-Cooper Rena G. Lapidus Mariola Sadowska Martin J. Edelman Ramachandra S. Hosmane 《Bioorganic & medicinal chemistry》2013,21(3):618-631
Judicial structural modifications of 5:7-fused ring-expanded nucleosides (RENs), based on molecular modeling studies with one of its known targets, human RNA helicase (hDDX3), led to the lead, novel, 5:7-5-fused tricyclic heterocycle (1). The latter exhibited promising broad-spectrum in vitro anti-cancer activity against a number of cancer cell lines screened. This paper describes our systematic, albeit limited, structure–activity relationship (SAR) studies on this lead compound, which produced a number of analogs with broad-spectrum in vitro anti-cancer activities against lung, breast, prostate, and ovarian cancer cell lines, in particular compounds 15i, 15j, 15m and 15n which showed IC50 values in submicromolar to micromolar range, and are worthy of further explorations. The SAR data also enabled us to propose a tentative SAR model for future SAR efforts for ultimate realization of optimally active and minimally toxic anti-cancer compounds based on the diimidazo[4,5-d:4′,5′-f][1,3]diazepine structural skeleton of the lead compound 1. 相似文献
253.
Sarosh Bejai Ramachandra Niranjan Raj Sathyanarayana Sivaramakrishnan Subramonium Shekar Hunthrike Shetty 《Journal of Phytopathology》2011,159(5):382-389
Sequence analysis of plant disease resistance genes shows similarity among themselves, with the presence of conserved motifs common to the nucleotide‐binding site (NBS). Oligonucleotide degenerate primers designed from the conserved NBS motifs encoded by several plant disease resistance genes were used to amplify resistance gene analogues (RGAs) corresponding to the NBS sequences from the genomic DNA of various plant species. Using specific primers designed from the conserved NBS regions, 22 RGAs were cloned and sequenced from pearl millet (Pennisetum glaucum L. Br.). Phylogenetic analysis of the predicted amino acid sequences grouped the RGAs into nine distinct classes. GenBank database searches with the consensus protein sequences of each of the nine classes revealed their conserved NBS domains and similarity to other known R genes of various crop species. One RGA 213 was mapped onto LG1 and LG7 in the pearl millet linkage map. This is the first report of the isolation and characterization of RGAs from pearl millet, which will facilitate the improvement of marker‐assisted breeding strategies. 相似文献
254.
Two carboxylesterases (ME-III and ME-IV) have been purified to apparent homogeneity from the seeds of Mucuna pruriens employing ammonium sulfate fractionation, cation exchange chromatography on CM-cellulose, gel-permeation chromatography on Sephadex G-100 and preparative PAGE. The homogeneity of the purified preparations was confirmed by polyacrylamide gel electrophoresis (PAGE), gel-electrofocussing and SDS–PAGE. The molecular weights determined by gel-permeation chromatography on Sephadex G-200 were 20.89 kDa (ME-III) and 31.62 kDa (ME-IV). The molecular weights determined by SDS–PAGE both in the presence and absence of 2-mercaptoethanol were 21 kDa (ME-III) and 30.2 kDa (ME-IV) respectively, suggesting a monomeric structure for both the enzymes. The enzymes were found to have Stokes radius of 2.4 nm (ME-III) and 2.7 nm (ME-IV). The isoelectric pH values of the enzymes, ME-III and ME-IV, were 6.8 and 7.4, respectively. ME-III and ME-IV were classified as carboxylesterases employing PAGE in conjunction with substrate and inhibitor specificity. The Km of ME-III and ME-IV with 1-naphthyl acetate as substrate was 0.1 and 0.166 mM while with 1-naphthyl propionate as substrate the Km was 0.052 and 0.0454 mM, respectively. As the carbon chain length of the acyl group increased, the affinity of the substrate to the enzyme increased indicating hydrophobic nature of the acyl group binding site. The enzymes exhibited an optimum temperature of 45 °C (ME-III) and 37 °C (ME-IV), an optimum pH of 7.0 (ME-III) and 7.5 (ME-IV) and both the enzymes (ME-III and ME-IV) were stable up to 120 min at 35 °C. Both the enzymes were inhibited by organophosphates (dichlorvos and phosphamidon), but resistant towards carbamates (carbaryl and eserine sulfate) and sulphydryl inhibitors (p-chloromercuricbenzoate, PCMB). 相似文献
255.
Yalamanchili N Syed R Chandra M Satti V Rao R Mohammed AH Nanne KM 《Indian journal of human genetics》2011,17(1):17-21
INTRODUCTION:
Designing a rapid, reliable and sensitive assay for detection of hepatitis B virus (HBV) variants by real-time PCR is challenging at best. A recent approach for quantifying the viral load using a sensitive fluorescent principle was brushed in this study.MATERIALS AND METHODS
: A total of 250 samples were collected from the outpatient unit, CLRD. Complete Human HBVDNA sequences (n = 944) were selected from the National Centre for Biotechnology Information (NCBI), primers and probes were designed and synthesized from the core, surface, and x region. Real-time based quantification was carried out using a standard kit and in-house generated standards and RT-PCR protocols.RESULTS AND DISCUSSION:
The standard calibration curve was generated by using serial dilution 102 to 108. The calibration curve was linear in a range from 102 to 108 copies/ml, with an R2 value of 0.999. Reproducibility as measured by dual testing of triplicates of serum samples was acceptable, with coefficients of variation at 6.5%, 7.5%, and 10.5%. Our results showed that amplification performance was good in the case of the x-region-based design (98%). Out of 100 negative samples screened by enzyme linked immunosorbent assay and the standard RT-PCR kit, one sample was detected as positive with the in-house developed RT-PCR assay, the positivity of the sample was confirmed by sequencing the amplified product, NCBI accession . EU684022CONCLUSION:
This assay is reproducible showing limited inter- and intra-assay variability. We demonstrate that the results of our assay correlated well with the standard kit for the HBV viral load monitor. 相似文献256.
Nabil A M Sultan Bhaskar G Maiya Musti J Swamy 《European journal of biochemistry》2004,271(15):3274-3282
Owing to the use of porphyrins in photodynamic therapy for the treatment of malignant tumors, and the preferential interaction of lectins with tumor cells, studies on lectin-porphyrin interaction are of significant interest. In this study, the interaction of several free-base and metalloporphyrins with Momordica charantia (bitter gourd) lectin (MCL) was investigated by absorption spectroscopy. Difference absorption spectra revealed that significant changes occur in the Soret band region of the porphyrins on binding to MCL. These changes were monitored to obtain association constants (Ka) and stoichiometry of binding. The tetrameric MCL binds four porphyrin molecules, and the stoichiometry was unaffected by the presence of the specific sugar, lactose. In addition, the agglutination activity of MCL was unaffected by the presence of the porphyrins used in this study, clearly indicating that porphyrin and carbohydrate ligands bind at different sites. Both cationic and anionic porphyrins bind to the lectin with comparable affinity (Ka =10(3)-10(5) m(-1)). The thermodynamic parameters associated with the interaction of several porphyrins, obtained from the temperature dependence of the Ka values, were found to be in the range: DeltaH degrees = -98.1 to -54.4 kJ.mol(-1) and DeltaS degrees =-243.9 to -90.8 J.mol(-1).K(-1). These results indicate that porphyrin binding to MCL is governed by enthalpic forces and that the contribution from binding entropy is negative. Enthalpy-entropy compensation was observed in the interaction of different porphyrins with MCL, underscoring the role of water structure in the overall binding process. Analysis of CD spectra of MCL indicates that this protein contains about 13%alpha-helix, 36%beta-sheet, 21%beta-turn, and the rest unordered structures. Binding of porphyrins does not significantly alter the secondary and tertiary structures of MCL. 相似文献
257.
258.
Priya BS Anil Kumar C Nanjunda Swamy S Basappa Naveen S Shashidhara Prasad J Rangappa KS 《Bioorganic & medicinal chemistry letters》2007,17(10):2775-2780
Compounds containing amide bond play a pivotal role in various pharmaceutical applications. 2-(2-(2-Ethoxybenzoylamino)-4-chlorophenoxy)-N-(2-ethoxybenzoyl)benzamine 4 is shown to be a potent antiangiogenic agent. In this study, we report the microwave-assisted synthesis, single crystal X-ray structure, and antiangiogenic effect of compound 4 in EAT cell induced angiogenesis. Treatment with compound 4 in vivo demonstrated down regulation of the secretion of VEGF in EAT cells and inhibition of blood vessel formation indicating the potential angioinhibitory effect of the compound in EAT cells. 相似文献
259.
Ujjinamatada RK Baier A Borowski P Hosmane RS 《Bioorganic & medicinal chemistry letters》2007,17(8):2285-2288
The title compound (4) was synthesized by the reaction of ethyl 1-(2,3,5-tri-O-benzoyl-beta-d-ribofuranosyl)-5-formylimidazole-4-carboxylate with excess guanidine in ethanol at reflux. Compound 4 was evaluated in vitro against NTPases/helicases of four different viruses of the Flaviviridae family, including the West Nile virus (WNV), hepatitis C virus (HCV), dengue virus (DENV), and the Japanese encephalitis virus (JEV), employing both an RNA and a DNA substrate. The compound showed activity against NTPase/helicase of WNV and HCV with an IC(50) of 23 and 37 microM, respectively, when a DNA substrate was employed, while no activity was observed when an RNA substrate was used. There was no activity against the NTPase/helicase of either DENV or JEV irrespective of whether an RNA or a DNA substrate was employed. Considering that Flaviviridae are RNA viruses, the observed absence of activity against an RNA substrate, but the presence of activity against a DNA substrate is intriguing and somewhat surprising. The preliminary studies show that compound 4 does not form a tight complex with either an RNA or a DNA substrate, suggesting that its mechanism of action may involve direct interaction with the enzyme. 相似文献
260.