共查询到20条相似文献,搜索用时 15 毫秒
1.
Jiang J Borisenko GG Osipov A Martin I Chen R Shvedova AA Sorokin A Tyurina YY Potapovich A Tyurin VA Graham SH Kagan VE 《Journal of neurochemistry》2004,90(5):1036-1049
Cyclo-oxygenase-2 (COX-2) is believed to induce neuronal oxidative stress via production of radicals. While oxygen radicals are not directly involved in COX-2-catalytic cycle, superoxide anion radicals have been repeatedly reported to play a critical role in COX-2-associated oxidative stress. To resolve the controversy, we characterized production of free radicals in PC12 cells in which COX-2 expression was manipulated either genetically or by direct protein transfection and compared them with those generated by a recombinant COX-2 in a cell-free system. Using spin-traps alpha-(4-pyridyl-1-oxide)-N-t-butylnitrone, 5,5-dimethyl-1-pyrroline-N-oxide and 4-((9-acridinecarbonyl) amino)-2,2,6,6- tetramethylpiperidine-1-oxyl (Ac-Tempo), we observed arachidonic acid (AA)-dependent production of carbon-centered radicals by heme-reconstituted recombinant COX-2. No oxygen radicals or thiyl radicals have been detected. COX-2 also catalyzed AA-dependent one-electron co-oxidation of ascorbate to ascorbate radicals. Next, we used two different approaches of COX-2 expression in cells, PCXII cells which express isopropyl-1-thio-beta-D-galactopyranoside inducible COX-2, and PC12 cells transfected with COX-2 using a protein delivery reagent, Chariot. In both models, COX-2-dependent AA-induced generation of carbon-centered radicals was documented using spin-traps and Ac-Tempo. No oxygen radical formation was detected in COX-2-transfected cells by either spin-traps or fluorogenic probe, dihydroethidium. In the presence of ascorbate, AA-induced COX-2-dependent ascorbate radicals were detected. AA caused a significant and selective oxidation of one of the major phospholipids, phosphatidylserine (PS). PS was not a direct substrate for COX-2 but was co-oxidized in the presence of AA. The radical generation and PS oxidation were inhibited by COX-2 inhibitors, niflumic acid, nimesulide, or NS-398. Thus, COX-2 generated carbon-centered radicals but not oxygen radicals or thiyl radicals are responsible for oxidative stress in AA-challenged PC12 cells overexpressing COX-2. 相似文献
2.
Martyn C.R. Symons 《Free radical research》2013,47(5):437-438
When aqueous solutions of DNA are stirred at room temperature, strand breaks occur extensively. Using various spin-traps, coupled with epr spectroscopy, we have shown that this does not proceed via homolysis. It is suggested that breaks occur by hydrolysis at strongly bent regions, momentarily induced by the stirring. 相似文献
3.
D W Cox 《Biochemical and biophysical research communications》1977,75(1):51-55
The spin-traps, 5,5′-Dimethyl-1-pyrroline-1-oxide and phenyltertiary-butylnitrone have been used to investigate the primary free radical involved in lipid peroxidation. In this report, we wish to present evidence that a NADPH-dependent hydroxyl radical (OH·), which may be the primary free radical that initiates lipid peroxidation, is generated in liver microsomes. A mechanism for the generation of the hydroxyl radical in liver microsomes is also postulated. 相似文献
4.
Symons MC 《Free radical research》2001,34(5):437-438
When aqueous solutions of DNA are stirred at room temperature, strand breaks occur extensively. Using various spin-traps, coupled with epr spectroscopy, we have shown that this does not proceed via homolysis. It is suggested that breaks occur by hydrolysis at strongly bent regions, momentarily induced by the stirring. 相似文献
5.
J. A. Silvester X. D. Wei M. J. Davies G. S. Timmins 《Redox report : communications in free radical research》2013,18(4):225-231
SummaryPhoto-oxidation of bovine serum albumin (BSA) by porphyrins produces protein-centred radicals that can be spin trapped by 3, 5-dibromo-4-nitrosobenzenesulphonic acid (DBNBS) and 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO). In the case of DMPO, a thiyl radical from the Cys-34 residue is trapped, whereas with DBNBS signals from both this thiyl and tertiary carbon-centred species are observed. However, specific chemical modification of the Cys-34 residue, in combination with dual-isotope spin-trapping techniques, shows that the signal assigned to the Cys-34 thiyl adduct with DBNBS is a nitroxide artefact resulting from sequential (non-radical) nucleophilic addition and oxidation. In contrast, both the Cys-34 thiyl DMPO adduct and the tertiary carbon-centred DBNBS adducts result from genuine spintrapping. This study shows that such artefacts can be detected—even with anisotropic EPR spectra—through the use of appropriately substituted spin-traps, and that nitroso spin-traps need to be employed with great care in systems containing free thiol groups. 相似文献
6.
Anthony R. Butler Bruce C. Gilbert Philippa Hulme Lee R. Irvine Louise Renton Adrian C. Whitwood 《Free radical research》1998,28(5):471-476
EPR experiments confirm that reaction of qinghaosu and some related endoperoxides with Fe2+ in aqueous acetonitrile leads to the production of carbon-centred radicals derived by rapid rearrangement of first-formed cyclic alkoxyl radicals. Signals obtained from qinghaosu itself with spin-traps DMPO and DBNBS are assigned to the adducts (15) and (16), a finding which accounts for the formation of the major products (11) and (14). 相似文献
7.
Stankova I Chuchkov K Wutzler P Schmidtke M 《Nucleosides, nucleotides & nucleic acids》2010,29(10):760-767
In the present study we have synthesized esters of acyclovir with cinnamic acids (p-coumaric, ferulic, and sinapic acids) and evaluated them for their antiviral and antioxidant potential. The antiviral activity of the newly synthesized compounds has been tested against human herpes virus 1 (HSV-1) in vitro. The results indicate that none of the synthesized compounds inhibits the tested virus strain. The antioxidant properties have been studied using 2,2-diphenyl-1-picrylhydrazyl (DPPH)* test. 相似文献
8.
Labeling of fructans in winter wheat stems 总被引:1,自引:0,他引:1
Fructans synthesized from newly formed assimilates accumulate in wheat stems as nonstructural carbohydrates. Experiments performed tested the hypothesis that the fructose moiety from translocated sucrose is used preferentially in biosynthesis of these fructans. Results indicated: (a) a large percentage of labeled sucrose was translocated and unloaded in an unaltered state; and (b) sucrose contributed its fructose moiety to fructan synthesis in stems. 相似文献
9.
This paper deals with the synthesis of a novel series of amphiphilic glycosylated spin-traps derived from alpha-Phenyl-N-tert-butyl nitrone (PBN) and an initial characterization of their anti-caspase-3 activity. Preliminary investigation of their anti-apoptosis effect showed they dramatically inhibit the activity of caspase-3 in cultured neuronal cells following induction of apoptosis by hydrogen peroxide. 相似文献
10.
Specific Initiation Site for Simian Virus 40 Deoxyribonucleic Acid Replication 总被引:7,自引:5,他引:2
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Replicating simian virus 40 (SV40) deoxyribonucleic acid (DNA) molecules have been isolated under conditions in which the newly synthesized DNA is uniformly labeled with (3)H-thymidine. These newly synthesized strands are released from the replicative intermediate molecules by alkaline treatment, and it has been possible to isolate single-stranded SV40 DNA which varies in size from 157,000 daltons (from molecules that are 10% replicated) to 1,360,000 daltons (85% replicated). The rates of duplex formation of newly synthesized DNA have been used to relate their genetic complexity to the extent of DNA replication. As DNA replication proceeds, the time required to effect 50% renaturation of the newly synthesized DNA increases at a proportional rate. The data establish that DNA replication is not initiated at random, but rather that there is a single specific initiation site for DNA replication. 相似文献
11.
Ivanka Stankova Kiril Chuchkov Peter Wutzler Michaela Schmidtke 《Nucleosides, nucleotides & nucleic acids》2013,32(10):760-767
In the present study we have synthesized esters of acyclovir (2–4) with cinnamic acids (p-coumaric, ferulic, and sinapic acids) and evaluated them for their antiviral and antioxidant potential. The antiviral activity of the newly synthesized compounds has been tested against human herpes virus 1 (HSV-1) in vitro. The results indicate that none of the synthesized compounds inhibits the tested virus strain. The antioxidant properties have been studied using 2,2-diphenyl-1-picrylhydrazyl (DPPH)* test. 相似文献
12.
13.
Spasova M Philipov S Nikolaeva-Glomb L Galabov AS Milkova Ts 《Bioorganic & medicinal chemistry》2008,16(15):7457-7461
The aporphine alkaloid glaucine has been converted into 3-aminomethylglaucine and its free amino group has been linked to cinnamic, ferulic, sinapic, o-, and p-coumaric acids. The antioxidative potential of the synthesized amides was studied against DPPH(*) test. All of the tested compounds demonstrated higher radical scavenging activity than glaucine and 3-aminomethylglaucine, and lower antioxidative effect than the free hydroxycinnamic acids. The newly synthesized compounds were tested in vitro for antiviral activity against viruses belonging to different taxonomic groups. 相似文献
14.
Synthesis,antioxidative and antiviral activity of hydroxycinnamic acid amides of thiazole containing amino acid 总被引:1,自引:0,他引:1
The synthesis and the biological (antioxidant and antiviral) activities of novel hydroxycinnamic acid amides of a thiazole
containing TFA.valine-4-carboxylic acid ethyl ester are reported. The amides have been synthesized from p-coumaric, ferulic and sinapic acids with the corresponding TFA.valine-thiazole-4-carboxylic acid ethyl ester using the coupling
reagent N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and 4-(dimethylamino) pyridine (DMAP) as a catalyst. The antioxidant
properties of the newly synthesized amides have been studied for then antioxidative activity using 2,2-diphenyl-1-picrylhydrazyl
(DPPH)* test. The newly synthesized compounds have been tested against the replication in vitro of influenza virus A (H3N2)
and human herpes virus 1 and 2 (HSV-1 and HSV-2). 相似文献
15.
H H Liem J A Grasso S H Vincent U Muller-Eberhard 《Biochemical and biophysical research communications》1990,167(2):528-534
Proteins are required for the efflux of heme from mitochondria and liposomes. The efflux from liposomes is independent of the heme-binding affinity of the protein (Biochem. 23:3715, 1984). We tested whether heme-binding proteins increase efflux of newly synthesized heme from structurally and functionally intact rat liver mitochondria. Mitochondria whose heme was labeled with 14C-delta-aminolevulinic acid, were incubated in the presence of glutathione transferases (GSTs), serum albumin (RSA) or heme-binding protein (HBP), all from the rat. HBP caused a 6-8 fold increase in efflux of newly synthesized heme as compared to that effected by RSA or GSTs. This result indicates that heme efflux from intact mitochondria, unlike that from liposomes, depends on the type of protein present and that HBP may specifically facilitate heme efflux from mitochondria. 相似文献
16.
Kuramochi K Matsui R Matsubara Y Nakai J Sunoki T Arai S Nagata S Nagahara Y Mizushina Y Ikekita M Kobayashi S 《Bioorganic & medicinal chemistry》2006,14(7):2151-2161
Epolactaene, a neuritogenic compound in human neuroblastoma SH-SY5Y, induces apoptosis in a human leukemia B-cell line, BALL-1. The apoptosis-inducing activities of 34 epolactaene derivatives, including those of the newly synthesized alpha-alkyl-alpha,beta-epoxy-gamma-lactam derivative and cyclopropane derivatives, were also tested. The structure-activity relationships of the epolactaene derivatives as an inducer of apoptosis are described. The alpha-acyl-alpha,beta-epoxy-gamma-lactam moiety as well as the hydrophobicity derived from the long alkyl side chain are both important for activity. Compound 1e displayed the strongest activity among all the synthesized compounds with an IC50 value of 0.70 microM. 相似文献
17.
Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenesis. In the current study, a series of novel pyrrolo[2,3-d]pyrimidine based-compounds was designed and synthesized as VEGFR-2 inhibitors, in accordance to the structure activity relationship (SAR) studies of known type II VEGFR-2 inhibitors. The newly synthesized compounds were evaluated for their ability to inhibit VEGFR-2 kinase enzyme in vitro. All the tested compounds demonstrated highly potent dose-related VEGFR-2 inhibition with IC50 values in nanomolar range. Among these compounds, pyrrolo[2,3-d]pyrimidine derivatives carrying biaryl urea moieties (12d and 15c) exhibited IC50 values of 11.9 and 13.6 nM respectively. Additionally, most of the newly synthesized final compounds were tested on 60 human cancer cell lines. Docking of these compounds into the inactive conformation of VEGFR-2 was performed which showed comparable binding modes to that of the FDA approved VEGFR-2 kinase inhibitors. These newly discovered potent kinase inhibitors could be considered as potential candidates for the development of new targeted anticancer agent. 相似文献
18.
Matthew R. Hemm Brian J. Paul Thomas D. Schneider Gisela Storz Kenneth E. Rudd 《Molecular microbiology》2008,70(6):1487-1501
The correct annotation of genes encoding the smallest proteins is one of the biggest challenges of genome annotation, and perhaps more importantly, few annotated short open reading frames have been confirmed to correspond to synthesized proteins. We used sequence conservation and ribosome binding site models to predict genes encoding small proteins, defined as having 16–50 amino acids, in the intergenic regions of the Escherichia coli genome. We tested expression of these predicted as well as previously annotated genes by integrating the sequential peptide affinity tag directly upstream of the stop codon on the chromosome and assaying for synthesis using immunoblot assays. This approach confirmed that 20 previously annotated and 18 newly discovered proteins of 16–50 amino acids are synthesized. We summarize the properties of these small proteins; remarkably more than half of the proteins are predicted to be single‐transmembrane proteins, nine of which we show co‐fractionate with cell membranes. 相似文献
19.