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1.
Ferrocene‐incorporated selenoureas 1‐(4‐methoxybenzoyl)‐3‐(4‐ferrocenylphenyl)selenourea (P4Me), 1‐(3‐methoxybenzoyl)‐3‐(4‐ferrocenylphenyl)selenourea (P3Me), and 1‐(2‐methoxybenzoyl)‐3‐(4‐ferrocenylphenyl)selenourea (P2Me) were synthesized and characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, atomic absorption spectroscopy, CHNS, and single‐crystal X‐ray diffraction. DNA interaction of the compounds was investigated with cyclic voltammetry, UV–visible spectroscopy, and viscometry, which is a prerequisite for anticancer agents. Drug‐DNA binding constant was found to vary in the sequence: KP4Me (4.9000 × 104 M?1) > KP2Me (2.318 × 104 M?1) > KP3Me (1.296 × 104 M?1). Antioxidant (1,1‐diphenyl‐2‐picrylhydrazyl), antifungal (against Faussarium solani and Helmentosporium sativum), and antibacterial (against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis) activities have also been reported in addition.  相似文献   

2.
Patterns of NPP,GPP, respiration,and NEP during boreal forest succession   总被引:1,自引:0,他引:1  
We combined year‐round eddy covariance with biometry and biomass harvests along a chronosequence of boreal forest stands that were 1, 6, 15, 23, 40, ~74, and ~154 years old to understand how ecosystem production and carbon stocks change during recovery from stand‐replacing crown fire. Live biomass (Clive) was low in the 1‐ and 6‐year‐old stands, and increased following a logistic pattern to high levels in the 74‐ and 154‐year‐old stands. Carbon stocks in the forest floor (Cforest floor) and coarse woody debris (CCWD) were comparatively high in the 1‐year‐old stand, reduced in the 6‐ through 40‐year‐old stands, and highest in the 74‐ and 154‐year‐old stands. Total net primary production (TNPP) was reduced in the 1‐ and 6‐year‐old stands, highest in the 23‐ through 74‐year‐old stands and somewhat reduced in the 154‐year‐old stand. The NPP decline at the 154‐year‐old stand was related to increased autotrophic respiration rather than decreased gross primary production (GPP). Net ecosystem production (NEP), calculated by integrated eddy covariance, indicated the 1‐ and 6‐year‐old stands were losing carbon, the 15‐year‐old stand was gaining a small amount of carbon, the 23‐ and 74‐year‐old stands were gaining considerable carbon, and the 40‐ and 154‐year‐old stands were gaining modest amounts of carbon. The recovery from fire was rapid; a linear fit through the NEP observations at the 6‐ and 15‐year‐old stands indicated the transition from carbon source to sink occurred within 11–12 years. The NEP decline at the 154‐year‐old stand appears related to increased losses from Clive by tree mortality and possibly from Cforest floor by decomposition. Our findings support the idea that NPP, carbon production efficiency (NPP/GPP), NEP, and carbon storage efficiency (NEP/TNPP) all decrease in old boreal stands.  相似文献   

3.
The emodin anthraquinone derivatives are generally used in traditional Chinese medicine due to their various pharmacological activities. In the present study, a series of emodin anthraquinone derivatives have been designed and synthesized, among which 1,3‐dihydroxy‐6,8‐dimethoxyanthracene‐9,10‐dione is a natural compound that has been synthesized for the very first time, and 1,3‐dimethoxy‐5,8‐dimethylanthracene‐9,10‐dione is a compound that has never been reported earlier. Interestingly, while total seven of these compounds showed neuraminidase inhibitory activity in influenza virus with inhibition rate more than 50 %, specific four compounds exhibited significant inhibition of tumor cell proliferation. The further results demonstrate that 1,3‐dimethoxy‐5,8‐dimethylanthracene‐9,10‐dione showed the best anticancer activity among all the synthesized compounds by inducing highest apoptosis rate to HCT116 cancer cells and arresting their G0/G1 cell cycle phase, through elevation of intracellular level of reactive oxygen species (ROS). Moreover, the binding of 1,3‐dimethoxy‐5,8‐dimethylanthracene‐9,10‐dione with BSA protein has thoroughly been investigated. Altogether, this study suggests the neuraminidase inhibitory activity and antitumor potential of the new emodin anthraquinone derivatives.  相似文献   

4.
Salix spp. nectar honey volatiles of Croatian origin were analyzed by headspace solid‐phase microextraction (HS‐SPME) and ultrasonic solvent extraction (USE), followed by gas chromatography and mass spectrometry (GC, GC/MS). Isolated volatiles were found in the honey headspace and extracts with almost exclusive distribution of several abundant compounds (e.g., phenylacetic acid, pinocembrin, 8‐hydroxy‐4,7‐dimethylcoumarin, and 3‐hydroxy‐transβ‐damascone in the extracts, or safranal and lilac alcohols in the headspace). Comparison with Croatian Salix spp. honeydew honey revealed similarities regarding distribution of important shikimate pathway derivatives (e.g., high percentage of phenylacetic acid) and several norisoprenoids (α‐isophorone and 4‐oxoisophorone). On the other hand, distinct features of this honey were occurrence of compounds such as pinocembrin, 8‐hydroxy‐4,7‐dimethylcoumarin, phenylacetonitrile, norisoprenoids (major ones: 3‐hydroxy‐transβ‐damascenone and transβ‐damascone), more pronounced variability of linalool‐derived compounds, as well as the abundance of 3‐methylpropanoic acid, 3‐methylbutanoic acid, 2‐methylpentanoic acid, and 3‐methylpentan‐1‐ol.  相似文献   

5.
Fiber‐based flexible thermoelectric energy generators are 3D deformable, lightweight, and desirable for applications in large‐area waste heat recovery, and as energy suppliers for wearable or mobile electronic systems in which large mechanical deformations, high energy conversion efficiency, and electrical stability are greatly demanded. These devices can be manufactured at low or room temperature under ambient conditions by established industrial processes, offering cost‐effective and reliable products in mass quantity. This article presents a critical overview and review of state‐of‐the‐art fiber‐based thermoelectric generators, covering their operational principle, materials, device structures, fabrication methods, characterization, and potential applications. Scientific and practical challenges along with critical issues and opportunities are also discussed.  相似文献   

6.
Cytotoxic and antimicrobial agents structurally based on quinazolinone, benzofuran and imidazole pharmacophores, have been designed and synthesized. Spectral (IR, 1H‐NMR) and elemental analysis data established the structures of these novel 3‐[1‐(1‐benzofuran‐2‐yl)‐2‐(4‐oxoquinazolin‐3(4H)‐yl)ethyl]‐1‐methyl‐1H‐imidazol‐3‐ium chloride hybrid derivatives. All the synthesized compounds were evaluated for in vitro cytotoxicity and antimicrobial activities. Cytotoxic evaluation using MTT assay revealed that compounds 12c , 12g and 12i exhibited significant cytotoxicity with IC50 values 1, 1, and 0.57 μm on this cell line, respectively. Biological activity of the synthesized compounds as antibacterial agent were also evaluated against three Gram‐negative (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi), three Gram‐positive (Staphylococcus aureus, Bacillus subtilis and Listeria monocitogenes) and one yeast‐like fungi (Candida albicans) strains. All compounds 12a  –  12i showed slightly higher activity against Gram‐positive bacteria than the Gram‐negative one. Among the nine new compounds screened, 3‐[1‐(5‐bromo‐1‐benzofuran‐2‐yl)‐2‐(6‐chloro‐4‐oxoquinazolin‐3(4H)‐yl)ethyl]‐1‐methyl‐1H‐imidazol‐3‐ium chloride ( 12e ) has pronounced higher antimicrobial activity against all tested strains. These results demonstrated potential importance of molecular hybridization in the development of new lead molecules with major cytotoxicity and antimicrobial activity.  相似文献   

7.
Sterols are a class of membrane‐reinforcing, ringed lipids which have a long history of examination in algae as a means of deriving chemotaxonomic relationships and as potential lipidic biomarkers. The Raphidophyceae represent a class of harmful, bloom‐forming, marine and freshwater algae. To date, there have been four published examinations of their sterol composition, focusing primarily on brown‐pigmented, marine species within the genera, Chattonella, Fibrocapsa, and Heterosigma. Lacking in these examinations has been the species Gonyostomum semen Ehrenb., which is a green‐pigmented, freshwater raphidophyte with a worldwide distribution. The goal of this study was to examine the sterol composition of this nuisance alga, determine the potential of using its sterol profile as a biomarker, and finally to determine if there is any intraspecific variability between isolates. We have examined 21 isolates of G. semen from a number of Scandinavian lakes, and all were found to produce two major sterols, 24‐ethylcholesta‐5,22E‐dien‐3β‐ol and 24‐ethylcholest‐5‐en‐3β‐ol, and 24‐methylcholest‐5‐en‐3β‐ol as a minor sterol; the presence of 24‐ethylcholesta‐5,22E‐dien‐3β‐ol differentiates G. semen from brown‐pigmented, marine raphidophytes which generally lack it. The results of this study indicate that isolates of G. semen from geographically separate lakes across Finland and Scandinavia have the same sterol biosynthetic pathway, and that there is no evolutionary divergence between the isolates with regard to sterol composition. The sterols of G. semen are not considered to be useful biomarkers for this particular organism because they are commonly found in other algae and plants.  相似文献   

8.
9.
While MC‐LR and MC‐RR share significant structural similarity, MC‐RR is less cytotoxic than MC‐LR. In the current study, we have compared the effects of MC‐LR and MC‐RR in Caco‐2 cells by evaluating cytotoxicity, oxidative stress (reactive oxygen species production), and the cellular proinflammatory response (IL‐6 and IL‐8 production). Following treatment with 100 µM microcystins (MC), cytotoxicity was two‐fold greater with MC‐LR as compared to MC‐RR after 24 h exposure. Whereas the reactive oxygen species production and IL‐6 secretion were similar following a 24‐h treatment with either MC, 100 µM MC‐LR induced a five‐fold greater IL‐8 secretion when compared to MC‐RR. Our study has demonstrated that, although both MC‐LR and MC‐RR induced some cytotoxicity in human intestinal cells, a major difference in IL‐8 production was observed between the two variants. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:253‐258, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21482  相似文献   

10.
In this study, three substituted polyhalogenated nitrobutadiene derivatives were synthesized. Compound 1‐[(2,3‐dibromopropyl)sulfanyl]‐1,3,4,4‐tetrachloro‐2‐nitrobuta‐1,3‐diene ( 4 ) was synthesized before by our group. Compounds 8‐{[1‐[(2,3‐dibromopropyl)sulfany]‐3,4,4‐trichloro‐2‐nitrobuta‐1,3‐butadien‐1‐yl}‐1,4‐dioxa‐8‐azaspiro[4.5]decane ( 5 ) and 1‐[(2,3‐dibromopropyl)sulfanyl]‐3,4,4‐trichloro‐N‐(4‐methylpiperazin‐1‐yl)‐2‐nitrobuta‐1,3‐diene‐1‐amine ( 6 ) were synthesized in this work as original compounds. Xanthine oxidase, elastase inhibition abilities, and antioxidant activities were investigated in this work for compounds 4 , 5 , and 6 . In this study, compounds 4 , 5 , and 6 exhibited antixanthine oxidase, antielastase, and antioxidant activities. Among the compounds screened, compound 4 exhibited xanthine oxidase and elastase inhibitor effect similar to the standard compound. Among the three tested compounds, compound 6 showed potent DPPH radical scavenging and reducing power activities. Therefore, these three compounds ( 4 , 5 , and 6 ) may be useful as an antixanthine oxidase, antielastase, and antioxidant agent in pharmaceutical and cosmetic industry.  相似文献   

11.
12.
A new A–π–D–π–A phenothiazine derivative, 2,2′‐((10‐octyl‐10H‐phenothiazine‐3,7‐diyl)bis (ethene‐2,1‐diyl))bis(1‐ethyl‐3,3‐dimethyl‐3H‐indol‐1‐ium)iodide (PTZ‐BEI) was prepared and fully characterized using infra‐red (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, ultraviolet–visible light and mass spectra. Electronic spectra of PTZ‐BEI solutions in solvents with different polarities displayed absorption bands (λmax) related to intramolecular charge transfer. In addition, the emission spectra of PTZ‐BEI solutions were strongly solvent dependent for both wavelength and intensity. Stokes’ shift ( increased with increasing solvent polarity up to 4105 cm?1 in the most polar solvent, dimethylformamide. The linear solvation‐energy relationship was utilized to investigate solvent dependency of the Stokes’ shifts. Relative quantum yield (φ ) of PTZ‐BEI was calculated. Finally, density functional theory was employed at the B3LYP level for geometrical optimization and simulation of electron spectra for the PTZ derivative in gaseous and solvated states to explore the solvent effect.  相似文献   

13.
Cover: Validation of the H3ac ChIP‐chip data by ChIP‐qPCR and identification of sites that are consistently enriched in H3ac when CFTR localizes in the nuclear interior. Sixty‐three qPCR primer pairs (numbered 1‐63) were used. Regions A‐E are indicated. See article by Muck et al., page 2607–2621 this issue.  相似文献   

14.
Crop sanitation (removal and chopping of residue corms and pseudostems following plant harvest) has been recommended as a ‘best bet’ means of reducing banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), populations. However, it has been unclear when such practices should be carried out and what types of residues should be destroyed. Therefore, trials were conducted in Uganda to determine C. sordidus distribution, timing of attack, and oviposition on crop residues and growing plants. Assessments were performed in on‐station trials on different aged standing and prostrate residues by destructive sampling. Similar data were collected from farmers’ fields maintained at low, moderate, and high levels of sanitation. In the on‐station trial, oviposition occurred on up to 120‐day‐old residues, although most occurred within 30 days of harvest. In a second on‐station experiment, oviposition on standing residues was not significantly affected by residue age. By contrast, oviposition on prostrate residues was two times higher on 4‐week‐old than on 2‐week‐old residues, while the number of larvae on 8‐week‐old residues was three times higher than on 2‐week‐old residues. The number of adults was twice as high on 16‐week‐old residues as that on 2‐week‐old residues for both prostrate and standing residues. Farmers’ fields maintained at high sanitation had 50% fewer eggs per residue than farms with low sanitation levels. In general, the number of immatures per residue was 50% higher on banana corms than on pseudostems. Numbers of larvae per residue were three times more abundant at low than at high sanitation levels. Residues in fields with high sanitation supported 50% fewer adults than residues in low sanitation fields. The results suggest that removal and splitting of corms after harvest is effective and practical in destroying immature growth stages of the pest and that such practices should be carried out soon after harvest.  相似文献   

15.
With a novel asymmetric Schiff‐base zinc complex ZnL (H2L = N‐(3‐methoxysalicylidene)‐N′‐(5‐bromo‐3‐methoxysalicylidene)phenylene‐1,2‐diamine), obtained from phenylene‐1,2‐diamine, 3‐methoxysalicylaldehyde and 5‐bromo‐3‐methoxysalicylaldehyde, as the precursor, a series of heterobinuclear Zn‐Ln complexes [ZnLnL(NO3)3(CH3CN)] (Ln = La, 1; Ln = Nd, 2; Ln = Eu, 3; Ln = Gd, 4; Ln = Tb, 5; Ln = Er, 6; Ln = Yb, 7) were synthesized by the further reaction with Ln(NO3)3·6H2O, and characterized by Fourier transform‐infrared, fast atom bombardment mass spectroscopy and elemental analysis. Photophysical studies of these complexes show that the strong and characteristic near‐infrared luminescence of Nd3+, Yb3+and Er3+ with emissive lifetimes in the microsecond range has been sensitized from the excited state of the asymmetric Schiff‐base ligand due to effective intramolecular energy transfer; the other complexes do not show characteristic emission due to the energy gap between the chromophore and lanthanide ions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

16.
The pigment composition of Phaeocystis antarctica was monitored under various conditions of light, temperature, salinity, and iron. 19′‐Hexanoyloxyfucoxanthin (Hex‐fuco) always constituted the major light‐harvesting pigment, with remarkably stable ratios of Hex‐fuco‐to‐chl a under the various environmental conditions. Increased pigment‐to‐chl a ratios at low irradiance confirmed the light‐harvesting function of Fucoxanthin (Fuco), 19′‐Hexanoyloxy‐4‐ketofucoxanthin (Hex‐kfuco), 19′‐butanoyloxyfucoxanthin (But‐fuco), and chl c2 and c3. Increased pigment‐to‐chl a ratios at high irradiance, low iron concentrations, and to a lesser extent at high salinity confirmed the photoprotective function of diadinoxanthin, diatoxanthin, and ß,ß‐carotene. Pigment ratios were not always according to expectations. The consistent increase in But‐fuco/chl at high temperature, high salinity, and low iron suggests a role in photoprotection rather than in light harvesting. Low Hex‐kfuco/chl ratios at high salinity were consistent with a role as light harvester, but the high ratios at high temperature were not, leaving the function of Hex‐kfuco enigmatic. Dedicated experiments were performed to test whether or not the light‐harvesting pigment Fuco could be converted into its structural relative Hex‐fuco, and vice versa, in response to exposure to light shifts. Rapid conversions could not be confirmed, but long‐term conversions cannot be excluded. New pigment ratios are proposed for chemotaxonomic applications. The ratios will improve pigment‐based diagnosis of algal species in waters dominated by P. antarctica.  相似文献   

17.
Intraflagellar transport (IFT) relies on the IFT complex and is required for ciliogenesis. The IFT‐B complex consists of 9–10 stably associated core subunits and six “peripheral” subunits that were shown to dissociate from the core structure at moderate salt concentration. We purified the six “peripheral” IFT‐B subunits of Chlamydomonas reinhardtii as recombinant proteins and show that they form a stable complex independently of the IFT‐B core. We suggest a nomenclature of IFT‐B1 (core) and IFT‐B2 (peripheral) for the two IFT‐B subcomplexes. We demonstrate that IFT88, together with the N‐terminal domain of IFT52, is necessary to bridge the interaction between IFT‐B1 and B2. The crystal structure of IFT52N reveals highly conserved residues critical for IFT‐B1/IFT‐B2 complex formation. Furthermore, we show that of the three IFT‐B2 subunits containing a calponin homology (CH) domain (IFT38, 54, and 57), only IFT54 binds αβ‐tubulin as a potential IFT cargo, whereas the CH domains of IFT38 and IFT57 mediate the interaction with IFT80 and IFT172, respectively. Crystal structures of IFT54 CH domains reveal that tubulin binding is mediated by basic surface‐exposed residues.  相似文献   

18.
It has been shown that hypoxia stimulation regulates bone formation, maintenance, and repair. Bone morphogenetic protein (BMP) plays important roles in osteoblastic differentiation and bone formation. However, the effects of hypoxia exposure on BMP‐2 expression in cultured osteoblasts are largely unknown. Here we found that hypoxia stimulation increased mRNA and protein levels of BMP‐2 by qPCR, Western blot and ELISA assay in osteoblastic cells MG‐63, hFOB and bone marrow stromal cells M2‐10B4. Integrin‐linked kinase (ILK) inhibitor (KP‐392), Akt inhibitor (1L‐6‐hydroxymethyl‐chiro‐inositol‐2‐[(R)‐2‐O‐methyl‐3‐O‐octadecylcarbonate]) or mammalian target of rapamycin (mTOR) inhibitor (rapamycin) inhibited the potentiating action of hypoxia. Exposure to hypoxia increased the kinase activity of ILK and phosphorylation of Akt and mTOR. Furthermore, hypoxia also increased the stability and activity of HIF‐1 protein. The binding of HIF‐1α to the HRE elements after exposure to hypoxia was measured by EMSA assay. Moreover, the use of pharmacological inhibitors or genetic inhibition revealed that both ILK/Akt and mTOR signaling pathway were potentially required for hypoxia‐induced HIF‐1α activation and subsequent BMP‐2 up‐regulation. Taken together, our results provide evidence that hypoxia enhances BMP‐2 expression in osteoblasts by an HIF‐1α‐dependent mechanism involving the activation of ILK/Akt and mTOR pathways. J. Cell. Physiol. 223:810–818, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

19.
Fat tissue, frequently the largest organ in humans, is at the nexus of mechanisms involved in longevity and age‐related metabolic dysfunction. Fat distribution and function change dramatically throughout life. Obesity is associated with accelerated onset of diseases common in old age, while fat ablation and certain mutations affecting fat increase life span. Fat cells turn over throughout the life span. Fat cell progenitors, preadipocytes, are abundant, closely related to macrophages, and dysdifferentiate in old age, switching into a pro‐inflammatory, tissue‐remodeling, senescent‐like state. Other mesenchymal progenitors also can acquire a pro‐inflammatory, adipocyte‐like phenotype with aging. We propose a hypothetical model in which cellular stress and preadipocyte overutilization with aging induce cellular senescence, leading to impaired adipogenesis, failure to sequester lipotoxic fatty acids, inflammatory cytokine and chemokine generation, and innate and adaptive immune response activation. These pro‐inflammatory processes may amplify each other and have systemic consequences. This model is consistent with recent concepts about cellular senescence as a stress‐responsive, adaptive phenotype that develops through multiple stages, including major metabolic and secretory readjustments, which can spread from cell to cell and can occur at any point during life. Senescence could be an alternative cell fate that develops in response to injury or metabolic dysfunction and might occur in nondividing as well as dividing cells. Consistent with this, a senescent‐like state can develop in preadipocytes and fat cells from young obese individuals. Senescent, pro‐inflammatory cells in fat could have profound clinical consequences because of the large size of the fat organ and its central metabolic role.  相似文献   

20.
In the pursuit of novel anticancer leads, new bisindole‐oxadiazoles were synthesized using propyl phosphonic anhydride as a mild and efficient reagent. The molecule, 3‐[5‐(1H‐indol‐3‐ylmethyl)‐1,3,4‐oxadiazol‐2‐yl]‐1H‐indole ( 3a ) exhibited selective cytotoxicity to MCF‐7 cells with a cell cycle arrest in the G1 phase. The mechanism of cytotoxicity of 3a involved caspase‐2‐dependent apoptotic pathway with characteristic apoptotic morphological alterations as observed in acridine orange/ethidium bromide and Hoechst staining. The wound healing migratory assay exhibited an intense impairment in the motility of MCF‐7 cells on incubation with 3a . Docking simulations with anti‐apoptotic protein Bcl‐2, which is also involved in cancer metastasis displayed good affinity and high binding energy of 3a into the well characterized BH3 binding site. The positive correlation between the Bcl‐2 binding studies and the results of in vitro investigations exemplifies compound 3a as a lead molecule exhibiting MCF‐7 differential cytotoxicity via apoptotic mode of cell death in addition to its anti‐metastatic activity.  相似文献   

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