The [Os(η6-pcym)(dpa)(VP)]PF6 (1-VP) complex contains the histone deacetylase (HDAC) inhibitor valproate (2-propylpentanoate; VP) as a monodentate O-donor ligand and shows ca. 3-fold higher in vitro cytotoxicity against A2780 human ovarian carcinoma cells than its chlorido analogue [Os(η6-pcym)(dpa)Cl]PF6 (1-Cl); pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene), dpa = 2,2'-dipyridylamine. The complex 1-VP showed promising selectivity towards the A2780 ovarian carcinoma cell line (IC50 = 20.9 μM) over normal human hepatocytes (IC50 > 200.0 μM). Moreover, the complex 1-VP was found to be inactive against MCF-7 (breast adenocarcinoma), PANC-1 (pancreatic adenocarcinoma) and HT-29 (colon carcinoma) up to a concentration of 100 μM. Detailed flow cytometry studies indicated that treatment of A2780 cells with complex 1-VP led to induction of apoptosis, production of reactive oxygen species (ROS) and superoxide (SO) anion radicals, as well as mitochondrial membrane potential depletion and cell cycle perturbations. The microscopic assessment (standard hematoxylin/eosin staining) revealed signs of morphological changes associated with the progression of apoptosis in A2780 cells treated with the IC50 concentration of the complex 1-VP. Consistent with the intracellular production of ROS and SO, the complex 1-VP induced hydroxyl radical formation, as proved by EPR spin trapping experiments. This case study suggests that replacement of the chlorido ligand of half-sandwich Os(ii) complexes by a releasable monodentate biologically active ligand (e.g., VP used in this study) is an effective strategy for the development of novel non-platinum cytotoxic agents.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   MeSH
• apoptóza účinky léků   MeSH
• cymeny MeSH
• inhibiční koncentrace 50 MeSH
• komplexní sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• kyselina valproová analogy a deriváty   chemie   MeSH
• lidé MeSH
• mitochondriální membrány účinky léků   MeSH
• monoterpeny chemie   MeSH
• nádorové buněčné linie MeSH
• osmium chemie   MeSH
• protinádorové látky chemická syntéza   chemie   farmakologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• superoxidy metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• 2,2'-dipyridylamine MeSH Prohlížeč
• 4-cymene MeSH Prohlížeč
• cymeny MeSH
• komplexní sloučeniny MeSH
• kyselina valproová MeSH
• monoterpeny MeSH
• osmium MeSH
• protinádorové látky MeSH
• reaktivní formy kyslíku MeSH
• superoxidy MeSH

Singlet molecular oxygen ((1)O2) contributes to protein damage triggering biophysical and biochemical changes that can be related with aging and oxidative stress. Serum albumins, such as bovine serum albumin (BSA), are abundant proteins in blood plasma with different biological functions. This paper presents a kinetic and spectroscopic study of the (1)O2-mediated oxidation of BSA using the tris(2,2'-bipyridine)ruthenium(II) cation [Ru(bpy)3](2+) as sensitizer. BSA quenches efficiently (1)O2 with a total (chemical+physical interaction) rate constant kt(BSA)=7.3(±0.4)×10(8)M(-1)s(-1), where the chemical pathway represented 37% of the interaction. This efficient quenching by BSA indicates the participation of several reactive residues. MALDI-TOF MS analysis of intact BSA confirmed that after oxidation by (1)O2, the mass protein increased the equivalent of 13 oxygen atoms. Time-resolved emission spectra analysis of BSA established that Trp residues were oxidized to N'-formylkynurenine, being the solvent-accessible W134 preferentially oxidized by (1)O2 as compared with the buried W213. MS confirmed oxidation of at least two Tyr residues to form dihydroxyphenylalanine, with a global reactivity towards (1)O2 six-times lower than for Trp residues. Despite the lack of MS evidences, kinetic and chemical analysis also suggested that residues other than Trp and Tyr, e.g. Met, must react with (1)O2. Modeling of the 3D-structure of BSA indicated that the oxidation pattern involves a random distribution of (1)O2 into BSA; allowing also the interaction of (1)O2 with buried residues by its diffusion from the bulk solvent through interconnected internal hydrophilic and hydrophobic grooves.

• Klíčová slova
• Albumin, Photosensitization, Protein oxidation, Reactive oxygen species, Singlet oxygen, Tryptophan fluorescence,
• MeSH
• 2,2'-dipyridyl analogy a deriváty   farmakologie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kinetika MeSH
• komplexní sloučeniny MeSH
• oxidace-redukce MeSH
• oxidační stres * MeSH
• sérový albumin hovězí chemie   metabolismus   MeSH
• singletový kyslík chemie   metabolismus   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• stárnutí metabolismus   patologie   MeSH
• tryptofan chemie   metabolismus   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• komplexní sloučeniny MeSH
• sérový albumin hovězí MeSH
• singletový kyslík MeSH
• tris(2,2-bipyridine)-ruthenium(II) MeSH Prohlížeč
• tryptofan MeSH

Aberrant expression of microRNAs (miRNAs), short non-coding RNA molecules regulating gene expression, is often found in tumor cells, making the miRNAs suitable candidates as cancer biomarkers. Electrochemistry is an interesting alternative to current standard methods of miRNA detection by offering cheaper instrumentation and faster assays times. In this paper, we labeled miRNA in a quick, simple, two-step procedure with electroactive complex of osmium(VI) and 2,2'-bipyridine, Os(VI)bipy, which specifically binds to the ribose at the 3'-end of the miRNA, and hybridized such labeled miRNA with biotinylated capture probe attached to the streptavidin magnetic beads. Labeled miRNA was then detected at hanging mercury drop electrode at femtomole level due to an electrocatalytic nature of the peak from the Os(VI)bipy label. We obtained good selectivity of the assay using elevated hybridization temperatures for better discrimination of perfect duplex from single and double mismatches. After optimization of the protocol, we demonstrated feasibility of our assay by detecting target miRNA in real total RNA samples isolated from human cancer cells.

• Klíčová slova
• Electrochemistry, Mercury electrodes, MicroRNA, Mismatch discrimination,
• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   MeSH
• biosenzitivní techniky metody   MeSH
• biotinylace MeSH
• elektrochemické techniky metody   MeSH
• hybridizace nukleových kyselin metody   MeSH
• lidé MeSH
• limita detekce MeSH
• magnetické jevy MeSH
• mikro RNA analýza   MeSH
• organokovové sloučeniny chemie   MeSH
• rtuť chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• mikro RNA MeSH
• organokovové sloučeniny MeSH
• osmium tetroxide-2,2'-bipyridine MeSH Prohlížeč
• rtuť MeSH

Titania nanofibers were fabricated using the industrial Nanospider(TM) technology. The preparative protocol was optimized by screening various precursor materials to get pure anatase nanofibers. Composite films were prepared by mixing a commercial paste of nanocrystalline anatase particles with the electrospun nanofibers, which were shortened by milling. The composite films were sensitized by Ru-bipyridine dye (coded C106) and the solar conversion efficiency was tested in a dye-sensitized solar cell filled with iodide-based electrolyte solution (coded Z960). The solar conversion efficiency of a solar cell with the optimized composite electrode (η = 7.53% at AM 1.5 irradiation) outperforms that of a solar cell with pure nanoparticle film (η = 5.44%). Still larger improvement was found for lower light intensities. At 10% sun illumination, the best composite electrode showed η = 7.04%, referenced to that of pure nanoparticle film (η = 4.69%). There are non-monotonic relations between the film's surface area, dye sorption capacity and solar performance of nanofiber-containing composite films, but the beneficial effect of the nanofiber morphology for enhancement of the solar efficiency has been demonstrated.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   MeSH
• barvicí látky chemie   MeSH
• elektrody MeSH
• elektrolyty chemie   MeSH
• nanočástice chemie   MeSH
• nanovlákna chemie   ultrastruktura   MeSH
• organokovové sloučeniny chemie   MeSH
• polymery chemie   MeSH
• sluneční energie * MeSH
• titan chemie   MeSH
• zdroje elektrické energie * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• barvicí látky MeSH
• bis(bipyridyl)ruthenium(II) MeSH Prohlížeč
• elektrolyty MeSH
• organokovové sloučeniny MeSH
• polymery MeSH
• titan MeSH
• titanium dioxide MeSH Prohlížeč

The lowest-lying spectral transitions in [ReX(CO)(3)(bpy)] (X = Cl, Br, I; bpy = 2,2'-bipyridine) complexes were calculated by means of spin-orbit time-dependent density functional theory (SO-TD-DFT) and spin-orbit multistate complete active space second-order perturbation theory (SO-MS-CASPT2). Computational results are compared with absorption spectra measured in different solvents and used to qualitatively explain the temperature dependence of the phosphorescence decay parameters that were measured for the whole series of complexes. Spin-orbit excited-state calculations interpret their electronic absorption spectra as arising from a bunch of spin mixed states with a singlet component of only 50-90% (depending on the halide), and attribute the phosphorescence decay to thermal population of spin-mixed states with a substantial singlet character.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   MeSH
• časové faktory MeSH
• fotochemické procesy MeSH
• kvantová teorie * MeSH
• molekulární struktura MeSH
• organokovové sloučeniny chemie   MeSH
• oxid uhelnatý chemie   MeSH
• rhenium chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• organokovové sloučeniny MeSH
• oxid uhelnatý MeSH
• rhenium MeSH

A series of mixed-ligand complexes [Cu(qui)(L)]NO(3)·xH(2)O (1-6), where Hqui = 2-phenyl-3-hydroxy-4(1H)-quinolinone, L = 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), bis(2-pyridyl)amine (ambpy) (3), 5-methyl-1,10-phenanthroline (mphen) (4), 5-nitro-1,10-phenanthroline (nphen) (5) and bathophenanthroline (bphen) (6), have been synthesized and fully characterized. The X-ray structures of [Cu(qui)(phen)]NO(3)·H(2)O (2) and [Cu(qui)(ambpy)]NO(3) (3a) show a slightly distorted square-planar geometry in the vicinity of the central copper(II) atom. An in vitro cytotoxicity study of the complexes found significant activity against human osteosarcoma (HOS) and human breast adenocarcinoma (MCF7) cell lines, with the best results for complex 6, where IC(50) equals to 2.1 ± 0.2 μM, and 2.2 ± 0.4 μM, respectively. The strong interactions of the complexes with calf thymus DNA (CT-DNA) and high ability to cleave pUC19 DNA plasmid were found. A correlation has been found between the in vitro cytotoxicity and DNA cleavage studies of the complexes.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   farmakologie   MeSH
• 4-chinolony chemie   farmakologie   MeSH
• DNA metabolismus   MeSH
• fenantroliny chemie   farmakologie   MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• měď chemie   farmakologie   MeSH
• molekulární modely MeSH
• nádorové buněčné linie MeSH
• nádory farmakoterapie   MeSH
• organokovové sloučeniny chemie   farmakologie   MeSH
• protinádorové látky chemie   farmakologie   MeSH
• skot MeSH
• štěpení DNA účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,10-phenanthroline MeSH Prohlížeč
• 2,2'-dipyridyl MeSH
• 2,2'-dipyridylamine MeSH Prohlížeč
• 4-chinolony MeSH
• 5-methyl-1,10-phenanthroline MeSH Prohlížeč
• 5-nitro-1,10-phenanthroline MeSH Prohlížeč
• bathophenanthroline MeSH Prohlížeč
• calf thymus DNA MeSH Prohlížeč
• DNA MeSH
• fenantroliny MeSH
• měď MeSH
• organokovové sloučeniny MeSH
• protinádorové látky MeSH

The complexation abilities of 2,2'-bipyridine (bipy) and 2,2'-bipyridyl-N,N'-dioxide (bipydiox) toward zinc(II) and the influence of these ligands on the properties and reactivities of the investigated complexes are compared by means of mass spectrometry, IR multiphoton dissociation spectroscopy, and theoretical calculations. The binding energy of bipydiox to zinc is slightly smaller than that of bipy, namely, by 0.1 eV in the mixed complex [(bipy)(bipydiox)ZnCl](+). Accordingly, the differences in the properties and reactivities of the complexes of zinc(II)/bipydiox and zinc(II)/bipy are only minor. The mechanism of decarboxylation of [(L)Zn(CH(3)COO)](+) (L = bipy or bipydiox) is investigated in detail. The substantial difference between the ligands stems only from the possibility of oxygen transfer from bipydiox, which is here, however, observed only as a high-energy channel in the fragmentation of complexes [(bipydiox)Zn(CH(3)COO)](+).

• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   MeSH
• ligandy MeSH
• molekulární struktura MeSH
• organokovové sloučeniny chemická syntéza   chemie   MeSH
• simulace molekulární dynamiky MeSH
• stereoizomerie MeSH
• zinek chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• ligandy MeSH
• organokovové sloučeniny MeSH
• zinek MeSH

A novel class of chiral superbases derived from the 2,2'-bipyridyl-N,N'-dioxide skeleton are presented. Combined experimental and theoretical data reveal that their proton affinities are on the order of 1050 kJ mol(-1), with protonation occurring at the oxygen atoms in a chelating manner. In the free bases, the oxygen atoms form a strongly polar binding site hidden in a hydrophobic envelope formed by the hydrocarbon backbone of the superbases. This chiral molecular structure can entrap polar intermediates or polarized transition structures and stabilize them in nonpolar solvents. Specifically, this mode of catalysis is shown for the coupling of benzaldehyde and allyltrichlorosilane.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   MeSH
• kyslík chemie   MeSH
• molekulární struktura MeSH
• rozpouštědla chemie   MeSH
• stereoizomerie MeSH
• termodynamika MeSH
• vazebná místa MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,2'-bipyridyl-N,N'-dioxide MeSH Prohlížeč
• 2,2'-dipyridyl MeSH
• kyslík MeSH
• rozpouštědla MeSH

Hereditary neurodegenerative diseases are connected with the expansion of trinucleotide repetitive sequences in genomic DNA. Molecular diagnosis of these diseases is based on the determination of the triplet repeat length. Currently used methods involve PCR amplification followed by electrophoretic determination of the amplicon size. We propose a novel electrochemical technique based on hybridization of target DNA (tDNA) immobilized at magnetic beads with a reporter probe (RP) complementary to the triplet repeats (12 units per RP). The biotin-labeled RP is detected via an enzyme-linked electrochemical assay involving binding of streptavidin-alkaline phosphatase conjugate and transformation of electroinactive 1-naphthyl phosphate to electroactive 1-naphthol. Pyrimidine residues within sequences flanking the homopurine (GAA)n repeat in tDNA are premodified with osmium tetroxide, 2,2'-bipyridine (Os,bipy), introducing electroactive labels in tDNA. The length of the triplet expansion is calculated from the ratio of the intensities of electrochemical signals of hybridized RP/tDNA-Os,bipy. The normalized signal increases linearly with the repeat length between 0 and about 200 triplet units, allowing for discrimination between normal, premutated, and mutated alleles. Application of this method for the detection of the asymptomatic heterozygous carrier of expanded alleles is demonstrated.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   chemie   MeSH
• alely MeSH
• alkalická fosfatasa metabolismus   MeSH
• biotin chemie   MeSH
• DNA analýza   genetika   MeSH
• elektrochemie metody   MeSH
• expanze trinukleotidových repetic * MeSH
• Friedreichova ataxie genetika   MeSH
• guanin MeSH
• hybridizace nukleových kyselin metody   MeSH
• lidé MeSH
• molekulární sondy - techniky MeSH
• naftaleny analýza   chemie   MeSH
• organokovové sloučeniny chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• alkalická fosfatasa MeSH
• biotin MeSH
• DNA MeSH
• guanin MeSH
• naftaleny MeSH
• organokovové sloučeniny MeSH
• osmium tetroxide-2,2'-bipyridine MeSH Prohlížeč

Mercury film electrodes (MFE) have recently been used in nucleic acid electrochemical analysis as alternatives to the classical mercury drop ones. DNA modified with osmium tetroxide, 2,2'-bipyridine (Os,bipy) can be detected with a high sensitivity at mercury electrodes via measurements of a catalytic osmium signal. In this paper we show that mercury film on a glassy carbon electrode can be used in voltammetric analysis of Os,bipy-modified DNA. Application of the MFE as a detection electrode in double-surface electrochemical DNA hybridization assay involving osmium labeling of target DNA is demonstrated.

• MeSH
• 2,2'-dipyridyl analogy a deriváty   analýza   chemie   MeSH
• barvení a značení metody   MeSH
• biokompatibilní potahované materiály chemie   MeSH
• biosenzitivní techniky metody   MeSH
• DNA sondy chemie   MeSH
• DNA analýza   chemie   MeSH
• elektrochemie metody   MeSH
• elektrody * MeSH
• hybridizace nukleových kyselin metody   MeSH
• organokovové sloučeniny analýza   chemie   MeSH
• rtuť chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• validační studie MeSH
• Názvy látek
• 2,2'-dipyridyl MeSH
• biokompatibilní potahované materiály MeSH
• calf thymus DNA MeSH Prohlížeč
• DNA sondy MeSH
• DNA MeSH
• organokovové sloučeniny MeSH
• osmium tetroxide-2,2'-bipyridine MeSH Prohlížeč
• rtuť MeSH