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1.
《Phytomedicine》2021
BackgroundCyclooxygenase-2 (COX-2) is an important enzyme with numerous biological functions. Overexpression of COX-2 has been associated with various inflammatory-related diseases and therefore, projected as an important pharmacological target.PurposeWe aimed to investigate the inhibitory potential of isolated bioactive compounds, 3-caffeoyl-4-dihydrocaffeoyl quinic acid (CDQ) and isorhamnetin 3-O-β-d-glucopyranoside (IDG), from Salicornia herbacea against COX-2 using both computational and in vitro approaches.MethodsComputational analysis, including molecular docking, molecular dynamics (MD) simulations, and post-simulations analysis, were employed to estimate the binding affinity and stability of CDQ and IDG in the catalytic pocket of COX-2 against Celecoxib as positive control. These predictions were further evaluated using in vitro enzyme inhibition as well as gene expression mediation in macrophages cells.ResultsMolecular docking analysis revealed substantial binding energy of CDQ (-6.1 kcal/mol) and IDG (-5.9 kcal/mol) with COX-2, which are lower than Celecoxib (-8.1 kcal/mol). MD simulations (100 ns) and post simulation analysis exhibited the substantial stability and binding affinity of docked CDQ and IDG compounds with COX-2. In vitro assays indicated significant COX-2 inhibition by CDQ (IC50 = 76.91 ± 2.33 μM) and IDG (IC50 = 126.06 ± 9.44 μM). This result supported the inhibitory potential of isolated bioactive compounds against COX-2. Also, a cellular level study revealed a downregulation of COX-2 expression in tumor necrosis factor-alpha stimulated RAW 264.7 macrophages treated with CDQ and IDG.ConclusionComputational and experimental analysis of CDQ and IDG from S. herbacea established their potential in the inhibition and mediation of COX-2. Hence, CDQ and IDG can be considered for therapeutic development against COX-2 linked disorders, such as inflammation and cancer. Furthermore, CDQ and IDG structures can be served as a lead compound for the development of advanced novel anti-inflammatory drugs. 相似文献
2.
Shan-Qing Wang Guang-Ze Wang Yu-Chun Li Feng Meng Shi-Gan Lin Zhen-Hu Zhu Ding-Wei Sun Chang-Hua He Xi-Min Hu Jian-Wei Du 《The Korean journal of parasitology》2015,53(1):35-41
Pyronaridine and artesunate have been shown to be effective in falciparum malaria treatment. However, pyronaridine is rarely used in Hainan Island clinically, and artesunate is not widely used as a therapeutic agent. Instead, conventional antimalarial drugs, chloroquine and piperaquine, are used, explaining the emergence of chloroquine-resistant Plasmodium falciparum. In this article, we investigated the sensitivity of P. falciparum to antimalarial drugs used in Hainan Island for rational drug therapy. We performed in vivo (28 days) and in vitro tests to determine the sensitivity of P. falciparum to antimalarial drugs. Total 46 patients with falciparum malaria were treated with dihydroartemisinin/piperaquine phosphate (DUO-COTECXIN) and followed up for 28 day. The cure rate was 97.8%. The mean fever clearance time (22.5±10.6 hr) and the mean parasite clearance time (27.3±12.2 hr) showed no statistical significance with different genders, ages, temperatures, or parasite density (P>0.05). The resistance rates of chloroquine, piperaquine, pyronarididine, and artesunate detected in vitro were 71.9%, 40.6%, 12.5%, and 0%, respectively (P<0.0001). The resistance intensities decreased as follows: chloroquine>piperaquine>pyronarididine>artesunate. The inhibitory dose 50 (IC50) was 3.77×10-6 mol/L, 2.09×10-6 mol/L, 0.09×10-6 mol/L, and 0.05×10-6 mol/L, and the mean concentrations for complete inhibition (CIMC) of schizont formation were 5.60×10-6 mol/L, 9.26×10-6 mol/L, 0.55×10-6 mol/L, and 0.07×10-6 mol/L, respectively. Dihydroartemisinin showed a strong therapeutic effect against falciparum malaria with a low toxicity. 相似文献
3.
Xiaobing Xu Wenya Lan Xinxin Jin Bin Wang Hongbo Yan Xi Chen Xiaowei Lai Li Zhang Xiaohua Zhang Zhaoshen Li 《PloS one》2014,9(12)
Background
This study was designed to examine a novel role of COX-2/PGE2 signaling as a regulator of PTPRJ expression in endothelial cells.Methods
A bioinformatics analysis of a whole genome array was carried out to search for regulators of PTPRJ expression in endothelial cells. PTPRJ expression was also measured in endothelial cells derived from a balloon injury-induced neointimal hyperplasia model in male New Zealand Rabbits. Changes in PTPRJ expression in HUVEC cells was examined by RT-PCR and western blotting after transfection of COX-2 plasmids or treatment with varying concentrations of a COX-2 inhibitor.Results
A significant correlation was identified between COX-2 and PTPRJ in (Pearson correlation coefficient = −0.87; n = 22; P<0.01, two-tailed). PTPRJ expression was reduced during the progression of neointimal hyperplasia after balloon injury, which correlated with an increase in COX-2 expression. In HUVECs, after transfection with 1 µg/ml, 0.5 µg/ml, or 0.25 µg/ml COX-2 plasmids, PTPRJ protein expression was reduced to 0.60- (±0.08), 0.75- (±0.09), and 0.88- (±0.04) fold, respectively, while mRNA expression was reduced to 0.15- (±0.03), 0.26- (±0.05), and 0.47- (±0.09) fold, respectively. After treatment of HUVECs with 10 µmol/L or 20 µmol/L celecoxib, the reduction in PTPRJ expression induced by COX-2 over-expression was not only rescued but in fact increased by 2.05-fold (±0.28) and 3.34-fold (±0.37), respectively, compared with control. GSE39264Conclusions
Our results suggest that COX-2/PGE2 signaling may function as a negative regulator of PTPRJ expression in endothelial cells both in vivo and vitro. 相似文献4.
Kinetic models provide the means to understand and predict the dynamic behaviour of enzymes upon different perturbations. Despite their obvious advantages, classical parameterizations require large amounts of data to fit their parameters. Particularly, enzymes displaying complex reaction and regulatory (allosteric) mechanisms require a great number of parameters and are therefore often represented by approximate formulae, thereby facilitating the fitting but ignoring many real kinetic behaviours. Here, we show that full exploration of the plausible kinetic space for any enzyme can be achieved using sampling strategies provided a thermodynamically feasible parameterization is used. To this end, we developed a General Reaction Assembly and Sampling Platform (GRASP) capable of consistently parameterizing and sampling accurate kinetic models using minimal reference data. The former integrates the generalized MWC model and the elementary reaction formalism. By formulating the appropriate thermodynamic constraints, our framework enables parameterization of any oligomeric enzyme kinetics without sacrificing complexity or using simplifying assumptions. This thermodynamically safe parameterization relies on the definition of a reference state upon which feasible parameter sets can be efficiently sampled. Uniform sampling of the kinetics space enabled dissecting enzyme catalysis and revealing the impact of thermodynamics on reaction kinetics. Our analysis distinguished three reaction elasticity regions for common biochemical reactions: a steep linear region (0> ΔGr >-2 kJ/mol), a transition region (-2> ΔGr >-20 kJ/mol) and a constant elasticity region (ΔGr <-20 kJ/mol). We also applied this framework to model more complex kinetic behaviours such as the monomeric cooperativity of the mammalian glucokinase and the ultrasensitive response of the phosphoenolpyruvate carboxylase of Escherichia coli. In both cases, our approach described appropriately not only the kinetic behaviour of these enzymes, but it also provided insights about the particular features underpinning the observed kinetics. Overall, this framework will enable systematic parameterization and sampling of enzymatic reactions. 相似文献
5.
Bright Yaw Vigbedor Clement Osei Akoto Ralph Kwakye Jonathan Osei-Owusu David Neglo Pius Kwashie 《International Journal of Biochemistry and Molecular Biology》2022,13(6):60
Background: Afzelia africana is a tropical plant with numerous ethno-medicinal benefits. The plant has been used for the treatment of pain, hernia, fever, malaria, inflammation and microbial infections. Objectives: To perform bioassay-guided fractionation, antioxidant and antimicrobial activities of the bark of Afzelia africana. Methods: Column chromatography fractionation, antioxidant activity (% (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 1,1-diphenyl picrylhydrazyl (DPPH) scavenging activity))), antimicrobial activity (microbroth dilution: Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), MBC/MIC ratio), and synergistic activities (Checkerboard assay: Fraction Inhibitory Concentration Index (FICI)). Results: Bioassay-guided fractionation of A. africana produced four fractions that displayed promising free radical scavenging activities in the ABTS (54-93)% and the DPPH (35-76)% assays in the ranking order of F1(93-54)>F4(81-58)>F2(74-58)>F3(72-55) and F3(77-42)>F1(64-46)>F4(55-44)>F2(47-35) respectively at a concentration range of 1.0-0.01 mg/mL. The fraction F1 (MBC: 2.5-5.0 mg/mL) and F4 (MBC: 1.25-10.0 mg/mL) exhibited broad spectrum of superior bactericidal effects than F2 (MBC≥100.0 mg/mL) and F3 (MBC: 12.5-100.0 mg/mL) against Staphylococcus mutans, Staphylococcus aureus, Escherichia coli, fluconazole-resistant Candida albicans, methicillin-resistant S. aureus, Bacillus subtilis, Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella typhi, and Candida albicans (standard strain). The two most active fractions (F1 and F4) reported synergistic effects (FICI≤0.5) against S. typhi whilst the F4 reported additional synergism against E. coli, K. pneumonia, and S. typhi when combined with ciprofloxacin. Furthermore, the two fractions reported synergistic effects against Escherichia coli, Klebsiella pneumonia, Salmonella typhi, and Pseudomonas aeruginosa when combined with tetracycline whilst F1 reported antifungal synergism against fluconazole resistant Candida albicans when combined with fluconazole and ketoconazole. Conclusion: The study has confirmed the antioxidant, antimicrobial and synergistic uses of A. africana for the treatment of both infectious and non-infectious disease. 相似文献
6.
Induction of leaf abscission in cotton is a common effect of urea- and adenine-type cytokinins 总被引:3,自引:0,他引:3
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Grossmann K 《Plant physiology》1991,95(1):234-237
Cytokinins of the urea and adenine type induced leaf abscission in young cotton (Gossypium hirsutum) plants in the following order of activity: N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (thidiazuron) » N-phenyl-N′-(2-chloro-4-pyridyl)urea > isopentenyladenine ≥ 6-benzyladenine > zeatin = dihydrozeatin > kinetin. It is suggested that ethylene production is implicated in this response because it was stimulated by the compounds in cotton leaf discs with nearly the same effectiveness. Moreover, similar to thidiazuron (JC Suttle [1985] Plant Physiol 78: 272-276), isopentenyladenine-induced defoliation was inhibited by aminoethoxyvinylglycine, and the effect was restored by 1-aminocyclopropane-1-carboxylic acid. 相似文献
7.
Chloramphenicol or its isomers, if supplied within 4 hr after the addition of Mn+2, prevented sporulation of Bacillus megaterium at concentrations that partially inhibited protein synthesis but which were neither bacteriostatic nor bactericidal. Likewise, sub-bactericidal quantities of the compounds, if supplied within 2 hr after the addition of Mn+2, suppressed formation of bacitracin by B. licheniformis. In contrast to previous reports that chloramphenicol is less active than its isomers against sporulation and peptide formation, the results of the present study indicated that the order and extent of these activities of the compounds is similar to that of their ability to prevent growth and to suppress protein synthesis; i.e., d(-)-threo > l(+)-erythro > d(-)-erythro. 相似文献
8.
Nada H. El-Dershaby Soad A. El-Hawash Shaymaa E. Kassab Hoda G. Dabees Ahmed E. Abdel Moneim Ibrahim A. Abdel Wahab Mohammad M. Abd-Alhaseeb Mostafa M. M. El-Miligy 《Journal of enzyme inhibition and medicinal chemistry》2022,37(1):1737
A new series of co-drugs was designed based on hybridising the dihydropteroate synthase (DHPS) inhibitor sulphonamide scaffold with the COX-2 inhibitor salicylamide pharmacophore through biodegradable linkage to achieve compounds with synergistic dual inhibition of COX-2/PGE2 axis and DHPS enzyme to enhance antibacterial activity for treatment of septicaemia. Compounds 5 b, 5j, 5n and 5o demonstrated potent in vitro COX-2 inhibitory activity comparable to celecoxib. 5j and 5o exhibited ED50 lower than celecoxib in carrageenan-induced paw edoema test with % PGE2 inhibition higher than celecoxib. Furthermore, 5 b, 5j and 5n showed gastric safety profile like celecoxib. Moreover, in vivo antibacterial screening revealed that, 5j showed activity against S.aureus and E.coli higher than sulfasalazine. While, 5o revealed activity against E.coli higher than sulfasalazine and against S.aureus comparable to sulfasalazine. Compound 5j achieved the target goal as potent inhibitor of COX-2/PGE2 axis and in vivo broad-spectrum antibacterial activity against induced septicaemia in mice. 相似文献
9.
Sandra Gouveia-Figueira Jessica Karlsson Alessandro Deplano Sanaz Hashemian Mona Svensson Marcus Fredriksson Sundbom Cenzo Congiu Valentina Onnis Christopher J. Fowler 《PloS one》2015,10(9)
Background
Increased endocannabinoid tonus by dual-action fatty acid amide hydrolase (FAAH) and substrate selective cyclooxygenase (COX-2) inhibitors is a promising approach for pain-relief. One such compound with this profile is 2-(2-fluorobiphenyl-4-yl)-N-(3-methylpyridin-2-yl)propanamide (Flu-AM1). These activities are shown by Flu-AM1 racemate, but it is not known whether its two single enantiomers behave differently, as is the case towards COX-2 for the parent flurbiprofen enantiomers. Further, the effects of the compound upon COX-2-derived lipids in intact cells are not known.Methodology/Principal Findings
COX inhibition was determined using an oxygraphic method with arachidonic acid and 2-arachidonoylglycerol (2-AG) as substrates. FAAH was assayed in mouse brain homogenates using anandamide (AEA) as substrate. Lipidomic analysis was conducted in unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Both enantiomers inhibited COX-2 in a substrate-selective and time-dependent manner, with IC50 values in the absence of a preincubation phase of: (R)-Flu-AM1, COX-1 (arachidonic acid) 6 μM; COX-2 (arachidonic acid) 20 μM; COX-2 (2-AG) 1 μM; (S)-Flu-AM1, COX-1 (arachidonic acid) 3 μM; COX-2 (arachidonic acid) 10 μM; COX-2 (2-AG) 0.7 μM. The compounds showed no enantiomeric selectivity in their FAAH inhibitory properties. (R)-Flu-AM1 (10 μM) greatly inhibited the production of prostaglandin D2 and E2 in both unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Levels of 2-AG were not affected either by (R)-Flu-AM1 or by 10 μM flurbiprofen, either alone or in combination with the FAAH inhibitor URB597 (1 μM).Conclusions/Significance
Both enantiomers of Flu-AM1 are more potent inhibitors of 2-AG compared to arachidonic acid oxygenation by COX-2. Inhibition of COX in lipopolysaccharide + interferon γ- stimulated RAW 264.7 cells is insufficient to affect 2-AG levels despite the large induction of COX-2 produced by this treatment. 相似文献10.
Karel Pauk Iveta Zadražilová Aleš Imramovský Jarmila Vinšová Michaela Pokorná Martina Masaříková Alois Čížek Josef Jampílek 《Bioorganic & medicinal chemistry》2013,21(21):6574-6581
Three series of salicylanilides, esters of N-phenylsalicylamides and 2-hydroxy-N-[1-(2-hydroxyphenylamino)-1-oxoalkan-2-yl]benzamides, in total thirty target compounds were synthesized and characterized. The compounds were evaluated against seven bacterial and three mycobacterial strains. The antimicrobial activities of some compounds were comparable or higher than the standards ampicillin, ciprofloxacin or isoniazid. Derivatives 3f demonstrated high biological activity against Staphylococcus aureus (?0.03 μmol/L), Mycobacterium marinum (?0.40 μmol/L) and Mycobacterium kansasii (1.58 μmol/L), 3g shows activity against Clostridium perfringens (?0.03 μmol/L) and Bacillus cereus (0.09 μmol/L), 3h against Pasteurella multocida (?0.03 μmol/L) and M. kansasii (?0.43 μmol/L), 3i against methicillin-resistant S. aureus and B. cereus (?0.03 μmol/L). The structure–activity relationships are discussed for all the compounds. 相似文献
11.
Incorporation of a cationic aminopropyl chain in DNA hairpins: thermodynamics and hydration 总被引:1,自引:1,他引:0
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We report on the physicochemical effects resulting from incorporating a 5-(3-aminopropyl) side chain onto a 2′-deoxyuridine (dU) residue in a short DNA hairpin. A combination of spectroscopy, calorimetry, density and ultrasound techniques were used to investigate both the helix–coil transition of a set of hairpins with the following sequence: d(GCGACTTTTTGNCGC) [N = dU, deoxythymidine (dT) or 5-(3-aminopropyl)-2′-deoxyuridine (dU*)], and the interaction of each hairpin with Mg2+. All three molecules undergo two-state transitions with melting temperatures (TM) independent of strand concentration that indicates their intramolecular hairpin formation. The unfolding of each hairpin takes place with similar TM values of 64–66°C and similar thermodynamic profiles. The unfavorable unfolding free energies of 6.4–6.9 kcal/mol result from the typical compensation of unfavorable enthalpies, 36–39 kcal/mol, and favorable entropies of ~110 cal/mol. Furthermore, the stability of each hairpin increases as the salt concentration increases, the TM-dependence on salt yielded slopes of 2.3–2.9°C, which correspond to counterion releases of 0.53 (dU and dT) and 0.44 (dU*) moles of Na+ per mole of hairpin. Absolute volumetric and compressibility measurements reveal that all three hairpins have similar hydration levels. The electrostatic interaction of Mg2+ with each hairpin yielded binding affinities in the order: dU > dT > dU*, and a similar release of 2–4 electrostricted water molecules. The main result is that the incorporation of the cationic 3-aminopropyl side chain in the major groove of the hairpin stem neutralizes some local negative charges yielding a hairpin molecule with lower charge density. 相似文献
12.
Magis Mandapathil Miroslaw J. Szczepanski Marta Szajnik Jin Ren Edwin K. Jackson Jonas T. Johnson Elieser Gorelik Stephan Lang Theresa L. Whiteside 《The Journal of biological chemistry》2010,285(36):27571-27580
Adaptive regulatory T cells (Tr1) are induced in the periphery upon encountering cognate antigens. In cancer, their frequency is increased; however, Tr1-mediated suppression mechanisms are not yet defined. Here, we evaluate the simultaneous involvement of ectonucleotidases (CD39/CD73) and cyclooxygenase 2 (COX-2) in Tr1-mediated suppression. Human Tr1 cells were generated from peripheral blood mononuclear cell-derived, sorted CD4+CD25− T cells and incubated with autologous immature dendritic cells, irradiated COX-2+ or COX-2− tumor cells, and IL-2, IL-10, and IL-15 (each at 10–15 IU/ml) for 10 days as described (Bergmann, C., Strauss, L., Zeidler, R., Lang, S., and Whiteside, T. L. (2007) Cancer Immunol. Immunother. 56, 1429–1442). Tr1 were phenotyped by multicolor flow cytometry, and suppression of proliferating responder cells was assessed in carboxyfluorescein diacetate succinimidyl ester-based assays. ATP hydrolysis was measured using a luciferase detection assay, and levels of adenosine or prostaglandin E2 (PGE2) in cell supernatants were analyzed by mass spectrometry or ELISA, respectively. Intracellular cAMP levels were measured by enzyme immunoassay. The COX-2+ tumor induced a greater number of Tr1 than COX-2− tumor (p < 0.05). Tr1 induced by COX-2+ tumor were more suppressive, hydrolyzed more exogenous ATP (p < 0.05), and produced higher levels of adenosine and PGE2 (p < 0.05) than Tr1 induced by COX-2− tumor. Inhibitors of ectonucleotidase activity, A2A and EP2 receptor antagonists, or an inhibitor of the PKA type I decreased Tr1-mediated suppression (p < 0.05), whereas rolipram, a PDE4 inhibitor, increased the intracellular cAMP level in responder cells and their susceptibility to Tr1-mediated suppression. Tr1 present in tumors or the peripheral blood of head and neck squamous cell carcinoma patients co-expressed COX-2, CD39, and CD73. A concomitant inhibition of PGE2 and adenosine via the common intracellular cAMP pathway might be a novel approach for improving results of immune therapies for cancer. 相似文献
13.
The effects of 3′ single-strand dangling-ends of different lengths, sequence identity of hairpin loop, and hairpin loop biotinylation at different loop residues on DNA hairpin thermodynamic stability were investigated. Hairpins contained 16 bp stem regions and five base loops formed from the sequence, 5′-TAGTCGACGTGGTCC-N5-GGACCACGTCGACTAG-En-3′. The length of the 3′ dangling-ends (En) was n = 13 or 22 bases. The identities of loop bases at positions 2 and 4 were varied. Biotinylation was varied at loop base positions 2, 3 or 4. Melting buffers contained 25 or 115 mM Na+. Average tm values for all molecules were 73.5 and 84.0°C in 25 and 115 mM Na+, respectively. Average two-state parameters evaluated from van’t Hoff analysis of the melting curve shapes in 25 mM Na+ were ΔHvH = 84.8 ± 15.5 kcal/mol, ΔSvH = 244.8 ± 45.0 cal/K·mol and ΔGvH = 11.9 ± 2.1 kcal/mol. In 115 mM Na+, two-state parameters were not very different at ΔHvH = 80.42 ± 12.74 kcal/mol, ΔSvH = 225.24 ± 35.88 cal/K·mol and ΔGvH = 13.3 ± 2.0 kcal/mol. Differential scanning calorimetry (DSC) was performed to test the validity of the two-state assumption and evaluated van’t Hoff parameters. Thermodynamic parameters from DSC measurements (within experimental error) agreed with van’t Hoff parameters, consistent with a two-state process. Overall, dangling-end DNA hairpin stabilities are not affected by dangling-end length, loop biotinylation or sequence and vary uniformly with [Na+]. Consider able freedom is afforded when designing DNA hairpins as probes in nucleic acid based detection assays, such as microarrays. 相似文献
14.
Chengyao Wu Guijuan Zhang Zai-Wei Zhang Xia Jiang Ziwen Zhang Huanhuan Li Hua-Li Qin Wenjian Tang 《Journal of enzyme inhibition and medicinal chemistry》2021,36(1):1860
To discover novel scaffolds as leads against dementia, a series of δ-aryl-1,3-dienesulfonyl fluorides with α-halo, α-aryl and α-alkynyl were assayed for ChE inhibitory activity, in which compound A10 was identified as a selective BuChE inhibitor (IC50 = 0.021 μM for eqBChE, 3.62 μM for hBuChE). SAR of BuChE inhibition showed: (i) o- > m- > p-; –OCH3 > –CH3 > –Cl (–Br) for δ-aryl; (ii) α-Br > α-Cl, α-I. Compound A10 exhibited neuroprotective, BBB penetration, mixed competitive inhibitory effect on BuChE (Ki = 29 nM), and benign neural and hepatic safety. Treatment with A10 could almost entirely recover the Aβ1-42-induced cognitive dysfunction to the normal level, and the assessment of total amount of Aβ1-42 confirmed its anti-amyloidogenic profile. Therefore, the potential BuChE inhibitor A10 is a promising effective lead for the treatment of AD. 相似文献
15.
The kinetics and thermodynamics of the adsorption process of reserpine adsorbed onto the strong acidic cationic exchange fiber (SACEF) were studied by batch adsorption experiments. The adsorption capacity strongly depended on pH values, and the optimum reserpine adsorption onto the SACEF occurred at pH = 5 of reserpine solution. With the increase of temperature and initial concentration, the adsorption capacity increased. The equilibrium was attained within 20 mins. The adsorption process could be better described by the pseudo-second-order model and the Freundlich isotherm model. The calculated activation energy Ea was 4.35 kJ/mol. And the thermodynamic parameters were: 4.97<ΔH<7.44 kJ/mol, -15.29<ΔG<-11.87 kJ/mol and 41.97<ΔS<47.35 J/mol·K. The thermodynamic parameters demonstrated that the adsorption was an endothermic, spontaneous and feasible process of physisorption within the temperature range between 283 K and 323 K and the initial concentration range between 100 mg/L and 300 mg/L. All the results showed that the SACEF had a good adsorption performance for the adsorption of reserpine from alcoholic solution. 相似文献
16.
Thomas Nagylaki 《Genetics》1975,79(3):545-550
For a system of n self-incompatibility alleles, neglecting mutation and random drift, it is shown that the completely symmetric equilibrium is locally stable, and any allelic frequency less than q = 1+a-(see PDF), where a = [2(n - 1)]-1, will increase. For all n, q > (2n)-1, but if n > > 1, q ≈ (2n)-1. 相似文献
17.
18.
María José Parra Karina I. Acu?a Angela Sierra-Almeida Camila Sanfuentes Alfredo Salda?a Luis J. Corcuera León A. Bravo 《PloS one》2015,10(12)
Some epiphytic Hymenophyllaceae are restricted to lower parts of the host (<60 cm; 10–100 μmol photons m-2 s-1) in a secondary forest of Southern Chile; other species occupy the whole host height (≥10 m; max PPFD >1000 μmol photons m-2 s-1). Our aim was to study the photosynthetic light responses of two Hymenophyllaceae species in relation to their contrasting distribution. We determined light tolerance of Hymenoglossum cruentum and Hymenophyllum dentatum by measuring gas exchange, PSI and PSII light energy partitioning, NPQ components, and pigment contents. H. dentatum showed lower maximum photosynthesis rates (Amax) than H. cruentum, but the former species kept its net rates (An) near Amax across a wide light range. In contrast, in the latter one, An declined at PPFDs >60 μmol photons m-2 s-1. H. cruentum, the shadiest plant, showed higher chlorophyll contents than H. dentatum. Differences in energy partitioning at PSI and PSII were consistent with gas exchange results. H. dentatum exhibited a higher light compensation point of the partitioning of absorbed energy between photochemical Y(PSII) and non-photochemical Y(NPQ) processes. Hence, both species allocated energy mainly toward photochemistry instead of heat dissipation at their light saturation points. Above saturation, H. cruentum had higher heat dissipation than H. dentatum. PSI yield (YPSI) remained higher in H. dentatum than H. cruentum in a wider light range. In both species, the main cause of heat dissipation at PSI was a donor side limitation. An early dynamic photo-inhibition of PSII may have caused an over reduction of the Qa+ pool decreasing the efficiency of electron donation to PSI. In H. dentatum, a slight increase in heat dissipation due to acceptor side limitation of PSI was observed above 300 μmol photons m-2s-1. Differences in photosynthetic responses to light suggest that light tolerance and species plasticity could explain their contrasting vertical distribution. 相似文献
19.
Tomas Gonec Jiri Kos Iveta Zadrazilova Matus Pesko Stanislava Keltosova Jan Tengler Pavel Bobal Peter Kollar Alois Cizek Katarina Kralova Josef Jampilek 《Bioorganic & medicinal chemistry》2013,21(21):6531-6541
In this study, a series of 22 ring-substituted 1-hydroxynaphthalene-2-carboxanilides were prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Mycobacterium marinum, Mycobacterium kansasii and Mycobacterium smegmatis. The compounds were also tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Most of tested compounds showed the antimycobacterial activity against the three strains comparable or higher than the standard isoniazid. N-(3-Fluorophenyl)-1-hydroxynaphthalene-2-carboxamide showed the highest biological activity (MIC = 28.4 μmol/L) against M. marinum, N-(4-fluorophenyl)-1-hydroxynaphthalene-2-carboxamide showed the highest biological activity (MIC = 14.2 μmol/L) against M. kansasii, and N-(4-bromophenyl)-1-hydroxynaphthalene-2-carboxamide expressed the highest biological activity (MIC = 46.7 μmol/L) against M. smegmatis. This compound and 1-hydroxy-N-(3-methylphenyl)naphthalene-2-carboxamide were the most active compounds against all three tested strains. The PET inhibition expressed by IC50 value of the most active compound 1-hydroxy-N-(3-trifluoromethylphenyl)naphthalene-2-carboxamide was 5.3 μmol/L. The most effective compounds demonstrated insignificant toxicity against the human monocytic leukemia THP-1 cell line. For all compounds, structure–activity relationships are discussed. 相似文献
20.
Lavanya Kakarla Pardhasaradhi Mathi Prasada Rao Allu Chakravarthy Rama Mahendran Botlagunta 《Bioinformation》2014,10(10):637-646
Cyperus scariosus (R.Br) belongs to the family Cyperaceae and it has a diverse medicinal importance. To identify human
cyclooxegenase-2 (COX-2) inhibitors from C. scariosus, the rhizome powder was exhaustively extracted with various solvents based
on the increasing polarity. Based on the presence and absence of secondary metabolites, we have selected the methanolic extract to
evaluate the anti-oxidant and anti-inflammatory activity. The same extract was further subjected to gas chromatography-mass
spectroscopy (GC-MS) analysis to identify the active compounds. Binding affinities of these compounds towards anti-inflammatory
protein COX-2 were analyzed using molecular docking interaction studies. Phytochemical analysis showed that methanol extract is
positive for all secondary metabolites. The antioxidant activity of the C. scariosus rhizomes methanolic extract (CSRME) is half to
that of ascorbic acid at 50 µg/ml. The anti-inflammatory activity of CSRME is higher than that of diclofenac sodium salt at high
concentration, which is evident from the dose dependent inhibition of bovine serum albumin denaturation at 40 µg/ml–5 mg/ml.
GC-MS analysis showed the presence of nine compounds, among all N-methyl-1-adamantaneacetamide and 1,5,diphenyl-2H-1,2,4-
triazine form a hydrogen bond interactions with Ser-530 and Tyr-385 respectively and found similar interactions with crystal
structure of diclofenac bound COX-2 protein. Benzene-1, 2-diol, 4-(4-bromo-3 chlorophenyl iminomethyl forms hydrogen bond
interactions with Thr-199 and Thr-200 as similar to crystallized COX-2 protein with valdecoxib. Collectively our results suggest that
CSRME contains medicinally important anti-inflammatory compounds and this justifies the use of this plant as a folklore medicine
for preventing inflammation associated disorders. 相似文献