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221.
Zídek Z Anzenbacher P Anzenbacherová E Buchar E Kmonícková E Potmesil P Holý A 《Journal of biomedical science》2006,13(3):295-301
Summary Interference of antiviral agent adefovir, i.e. 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA) with microsomal drug metabolizing system was investigated in rats. The content of total liver cytochrome P450 (CYP) was lowered while that of its denaturated form, P420, was elevated in animals intraperitoneally treated with PMEA (25 mg/kg). Similar effect was observed after treatment with a prodrug of adevofir, adefovir dipivoxil (bisPOM-PMEA). The CYP2E1-dependent formation of 4-nitrocatechol from p-nitrophenol was diminished, though the specific activity of p-nitrophenol hydroxylase remained unchanged. PMEA had no influence on expression of CYP2E1 protein and mRNA and mRNAs of other P450 isoenzymes (1A1, 1A2, 2C11, 3A1, 3A2, and 4A1). It may be concluded that repeated systemic administration of higher doses of PMEA results in a partial degradation of rat CYP protein to inactive P420. 相似文献
222.
Zdeněk Paris Piya Changmai Mary Anne T. Rubio Alena Zíková Kenneth D. Stuart Juan D. Alfonzo Julius Luke? 《The Journal of biological chemistry》2010,285(29):22394-22402
Fe/S clusters are part of the active site of many enzymes and are essential for cell viability. In eukaryotes the cysteine desulfurase Nfs (IscS) donates the sulfur during Fe/S cluster assembly and was thought sufficient for this reaction. Moreover, Nfs is indispensable for tRNA thiolation, a modification generally required for tRNA function and protein synthesis. Recently, Isd11 was discovered as an integral part of the Nfs activity at an early step of Fe/S cluster assembly. Here we show, using a combination of genetic, molecular, and biochemical approaches, that Isd11, in line with its strong association with Nfs, is localized in the mitochondrion of T. brucei. In addition to its involvement in Fe/S assembly, Isd11 also partakes in both cytoplasmic and mitochondrial tRNA thiolation, whereas Mtu1, another protein proposed to collaborate with Nfs in tRNA thiolation, is required for this process solely within the mitochondrion. Taken together these data place Isd11 at the center of these sulfur transactions and raises the possibility of a connection between Fe/S metabolism and protein synthesis, helping integrate two seemingly unrelated pathways. 相似文献
223.
Zdeněk Trávní?ek Igor Popa Radek Zbo?il Ji?í Mikulík 《Journal of inorganic biochemistry》2010,104(4):405-11728
The first FeIII complexes 1-6 with cyclin-dependent kinase (CDK) inhibitors of the type [Fe(Ln)Cl3]·nH2O (n = 0 for 1, 1 for 2, 2 for 3-6; L1-L6 = C2- and phenyl-substituted CDK inhibitors derived from 6-benzylamino-9-isopropylpurine), have been synthesized and characterized by elemental analysis, IR, 57Fe Mössbauer, 1H and 13C NMR, and ES+ mass spectroscopies, conductivity and magnetic susceptibility measurements, and thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The study revealed that the compounds are mononuclear, tetrahedral high-spin (S = 5/2) FeIII complexes with an admixture of an S = 3/2 spin state originating probably from five-coordinated FeIII ions either connecting with a bidentate coordination mode of the CDK inhibitor ligand or relating to the possibility that one crystal water molecule enters the coordination sphere of the central atom in a portion of molecules of the appropriate complex. Nearly spin-only value of the effective magnetic moment (5.82 μeff/μB) was determined for compound 1 due to absence of crystal water molecule(s) in the structure of the complex. Based on NMR data and DFT calculations, we assume that the appropriate organic ligand is coordinated to the FeIII ion through the N7 atom of a purine moiety. The cytotoxicity of the complexes was tested in vitro against selected human cancer cell lines (G-361, HOS, K-562 and MCF-7) along with the ability to inhibit the CDK2/cyclinE kinase. The best cytotoxicity (IC50: 4-23 μM) and inhibition activity (IC50: 0.02-0.09 μM) results have been achieved in the case of complexes 2-4, and complexes 3, 4 and 6, respectively. In addition, the X-ray structure of 2-chloro-6-benzylamino-9-isopropylpurine, i.e. a precursor for the preparation of L1, L4 and L5, is also described. 相似文献
224.
Jana Steigerová Jana Oklešťková Monika Levková Lucie Rárová Zdeněk Kolář Miroslav Strnad 《Chemico-biological interactions》2010,188(3):487-496
Brassinosteroids (BRs) are plant hormones that appear to be ubiquitous in both lower and higher plants. Recently, we published the first evidence that some natural BRs induce cell growth inhibitory responses in several human cancer cell lines without affecting normal non-tumor cell growth (BJ fibroblasts). The aim of the study presented here was to examine the mechanism of the antiproliferative activity of the natural BRs 28-homocastasterone (28-homoCS) and 24-epibrassinolide (24-epiBL) in human hormone-sensitive and -insensitive (MCF-7 and MDA-MB-468, respectively) breast cancer cell lines. The effects of 6, 12 and 24 h treatments with 28-homoCS and 24-epiBL on cancer cells were surveyed using flow cytometry, Western blotting, TUNEL assays and immunofluorescence analyses. The studied BRs inhibited cell growth and induced blocks in the G1 cell cycle phase. ER-α immunoreactivity was uniformly present in the nuclei of control MCF-7 cells, while cytoplasmic speckles of ER-α immunofluorescence appeared in BR-treated cells (IC50, 24 h). ER-β was relocated to the nuclei following 28-homoCS treatment and found predominantly at the periphery of the nuclei in 24-epiBL-treated cells after 24 h of treatment. These changes were also accompanied by down-regulation of the ERs following BR treatment. In addition, BR application to breast cancer cells resulted in G1 phase arrest. Furthermore, TUNEL staining and double staining with propidium iodide and acridine orange demonstrated the BR-mediated induction of apoptosis in both cell lines, although changes in the expression of apoptosis-related proteins were modulated differently by the BRs in each cell line. The studied BRs seem to exert potent growth inhibitory effects via interactions with the cell cycle machinery, and they could be highly valuable leads for agents for managing breast cancer. 相似文献
225.
Zdeněk Drahota Hana N?sková Václav Zídek Michal Pravenec 《Biochemical and biophysical research communications》2010,391(3):1348-1351
The functional role of CD36 protein detected in mitochondrial fractions in long chain fatty acid (LCFA) oxidation is unclear due to conflicting results obtained in Cd36 knockout mice and experiments using sulfo-N-succinimidyl oleate (SSO) for inhibition of CD36 mediated LCFA transport. We investigated effect of SSO on mitochondrial respiration and found that SSO substantially inhibits not only LCFA oxidation, but also oxidation of flavoprotein- and NADH-dependent substrates and generation of mitochondrial membrane potential. Experiments in rat liver, heart and kidney mitochondria demonstrated a direct effect on mitochondrial respiratory chain with the most pronounced inhibition of the complex III (IC50 4 μM SSO). The results presented here show that SSO is a potent and irreversible inhibitor of mitochondrial respiratory chain. 相似文献
226.
Jaroslav Novák Marie Zarevúcka Zdeněk Wimmer Richard Tykva 《Biotechnology letters》2001,23(18):1517-1522
The enantioselectivity potential of five strains of Saccharomyces cerevisiae was studied for the reduction of ethyl N-{2-{4-[(2-oxocyclohexyl)methyl]phenoxy}ethyl} carbamate (1), an insect juvenile hormone bioanalog. The products of the reaction, the cis and trans isomers of ethyl N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl} carbamate (2 and 3), were obtained in 45–49% (w/w) chemical yields and with 79 to > 99% enantiomeric purity values. The absolute configurations of the major products were assigned as ethyl (1S,2S)-N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl} carbamate (2) and ethyl (1S,2R)-N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl} carbamate (3). The products 2 and 3 belong to the series of the chiral insect juvenile hormone analogs. 相似文献
227.
Miroslav Vacek Marie Zarevúcka Zdeněk Wimmer Karel Stránský Martina Macková Kateřina Demnerová 《Biotechnology letters》2001,23(1):27-32
Alcoholysis of blackcurrant oil mediated by Pseudomonas fluorescens lipase performed at 30°C in ethanol (96%, v/v) used both as a solvent and as a reactant. After 16 h, 95% of triacylglycerols present in the oil was converted into a mixture consisting of fatty acid ethyl esters, free fatty acids, monoacylglycerols and diacylglycerols. The highest amount of fatty acid ethyl esters (52%) was achieved after 8 h. 相似文献
228.
229.
Zídek Z Kmonícková E Holý A 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2005,149(2):315-319
Biological effectiveness of antiviral acyclic nucleoside phosphonate adefo vir, 9-[2-(phosphonomethoxy)ethy]ade nine (PMEA) and its more lipophilic (bis)pivaloyloxymethyl ester prodrug adefovir dipivoxil (bis-POM-PMEA) were compared under in vitro conditions in mammalian cell systems. Proliferation of murine splenocytes was inhibited in a concentration-dependent manner, the bis-POM-PMEA being more effective than PMEA. In contrast to PMEA, bis-POM-PMEA inhibited production of nitric oxide (NO) in macrophages activated with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). Viability of both splenocytes and macrophages remained uninfluenced by PMEA, whereas pronounced cytocidal effects were exhibited by bis-POM-PMEA. The IC(50)s reached the values of 15 microM and 30 microM in cultures of macrophages and splenocytes, respectively (assayed at the interval of 24 hrs). The effects could partly be mimicked by formaldehyde, a decomposition product of the pivoxil moiety of bis-POM-PMEA. The other possible product, pivalic acid, was ineffective in this respect. The present data are consistent with the view that pivoxil prodrug of PMEA, bis-POM-PMEA possesses enhanced but also broader spectrum of biological effects than the parent compound. 相似文献
230.
Isoquinoline Alkaloids from Fumaria officinalis L. and Their Biological Activities Related to Alzheimer's Disease 下载免费PDF全文
Jakub Chlebek Zdeněk Novák Dominika Kassemová Marcela Šafratová Jan Kostelník Lukáš Malý Miroslav Ločárek Lubomír Opletal Anna Hošt'álková Martina Hrabinová Jiří Kuneš Pavlína Novotná Marie Urbanová Lucie Nováková Kateřina Macáková Daniela Hulcová Petr Solich Concepción Pérez Martín Daniel Jun Lucie Cahlíková 《化学与生物多样性》2016,13(1):91-99
Two new isoquinoline alkaloids, named fumaranine ( 2 ) and fumarostrejdine ( 10 ), along with 18 known alkaloids were isolated from aerial parts of Fumaria officinalis. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses and by comparison with literature data. The absolute configuration of the new compound 2 was determined by comparing its circular dichroism spectra with those of known analogs. Compounds isolated in sufficient amounts were evaluated for their acetylcholinesterase, butyrylcholinesterase, prolyl oligopeptidase (POP), and glycogen synthase kinase‐3β inhibitory activities. Parfumidine ( 8 ) and sinactine ( 15 ) exhibited potent POP inhibition activities (IC50 99±5 and 53±2 μM , resp.). 相似文献