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Azra Rabbani-chadegani - One of the best experts on this subject based on the ideXlab platform.

  • Investigation on the chromium oxide interaction with soluble chromatin and histone H1: A spectroscopic study
    International Journal of Biological Macromolecules, 2014
    Co-Authors: Khatereh Khorsandi, Azra Rabbani-chadegani
    Abstract:

    Chromatin has been introduced as a tool for studying heavy metals action in nuclei. Chromium oxide is highly soluble and toxic with chronic exposure leading to mutagenesis and carcinogenesis. In the present study, for the first time, the binding affinity of chromium oxide to rat liver chromatin and histone proteins was investigated. Reduction of chromatin absorbencies at 210 and 260 nm (hypochromicity) and Fluorescence Emission Intensity upon metal binding represented quenching of the metal with chromatin chromophores. Binding isotherms demonstrated a positive cooperative binding pattern revealing higher affinity of the metal to chromatin compared to DNA as confirmed by the binding constants. Melting temperature of chromatin was altered in a dose dependent manner and suggests partial removal of histones from the chromatin at metal concentrations higher than 15 μg/ml. Chromium oxide decreased the absorbance of histone H1 at 210 nm (hypochromicity) and Fluorescence Emission Intensity revealed quenching of the metal with tyrosine residue located in the core domain of H1. Also the interaction of chromium oxide with histone H1 increased its secondary structures. The results suggest toxic effect of very low concentrations of chromium oxide on chromatin and in this reaction both DNA and histones are involved.

  • Studies on the genotoxic effect of chromium oxide (Cr VI): interaction with deoxyribonucleic acid in solution.
    Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2012
    Co-Authors: Khatereh Khorsandi, Azra Rabbani-chadegani
    Abstract:

    Abstract Chromium is a toxic and carcinogenic compound widely distributed in environment. In the present study we have investigated the interaction of chromium oxide with DNA employing UV/vis and Fluorescence spectroscopy as well as Circular dichroism, thermal denaturation, retardation polyacrylamide gel electrophoresis and DNA-cellulose affinity techniques. The results showed that the binding of chromium oxide to DNA is concentration dependent; at low concentration shows a little effect but ant higher concentrations (>100 μg/ml) reduced the absorbance at 260 and 210 nm producing hypochromicity. Also λmax of the metal at 210, 260 and 350 nm was reduced. DNA chromophores quenched with the chromium oxide and decreased Fluorescence Emission Intensity. Upon binding of the metal to DNA the elliplicity at positive extreme was decreased (275 nm) and increased the ellipticity of the DNA at negative extreme 245 nm. Thermal denaturation profile of DNA shifted to higher degrees upon chromium oxide binding which accompanied by hypochromicity. Also, affinity of chromium oxide to double stranded DNA was higher than single stranded DNA. From the result it is concluded that chromium oxide interacts with DNA via two modes of interaction inducing structural changes and DNA compaction evidence providing chromium oxide genotoxicity.

  • A comparison of the effect of anticancer drugs, idarubicin and adriamycin, on soluble chromatin
    European Journal of Pharmacology, 2007
    Co-Authors: Zohreh Zahraei, Azra Rabbani-chadegani
    Abstract:

    Abstract The biological activity of an anticancer agent is related to its physicochemical interaction with biological receptors. In the present study we have investigated and compared the affinity and mode of action of two potent anticancer drugs, adriamycin and idarubicin on soluble chromatin using ultraviolet/visible and Fluorescence spectroscopy, hydroxyapatite (HAP) chromatography and gel electrophoresis techniques. The results show that addition of various concentrations of drugs to chromatin solution individually, reduced both absorbance and Fluorescence Emission Intensity of chromatin and precipitated it in a dose dependent manner, however, the extent of reduction was different for two drugs used. This effect was also observed on the histone gel patterns of the drug treated samples revealing that the chromatin is less affected by idarubicin compared to adriamycin implying higher aggregation of chromatin with the former. As hydroxyapatite chromatograms show, histone H1 represented the highest drug binding activity. The results suggest that although adriamycin and idarubicin are both grouped anthracycline antibiotic anticancer drugs, they differ considerably on their binding affinity to cellular chromatin.

Khatereh Khorsandi - One of the best experts on this subject based on the ideXlab platform.

  • Investigation on the chromium oxide interaction with soluble chromatin and histone H1: A spectroscopic study
    International Journal of Biological Macromolecules, 2014
    Co-Authors: Khatereh Khorsandi, Azra Rabbani-chadegani
    Abstract:

    Chromatin has been introduced as a tool for studying heavy metals action in nuclei. Chromium oxide is highly soluble and toxic with chronic exposure leading to mutagenesis and carcinogenesis. In the present study, for the first time, the binding affinity of chromium oxide to rat liver chromatin and histone proteins was investigated. Reduction of chromatin absorbencies at 210 and 260 nm (hypochromicity) and Fluorescence Emission Intensity upon metal binding represented quenching of the metal with chromatin chromophores. Binding isotherms demonstrated a positive cooperative binding pattern revealing higher affinity of the metal to chromatin compared to DNA as confirmed by the binding constants. Melting temperature of chromatin was altered in a dose dependent manner and suggests partial removal of histones from the chromatin at metal concentrations higher than 15 μg/ml. Chromium oxide decreased the absorbance of histone H1 at 210 nm (hypochromicity) and Fluorescence Emission Intensity revealed quenching of the metal with tyrosine residue located in the core domain of H1. Also the interaction of chromium oxide with histone H1 increased its secondary structures. The results suggest toxic effect of very low concentrations of chromium oxide on chromatin and in this reaction both DNA and histones are involved.

  • Studies on the genotoxic effect of chromium oxide (Cr VI): interaction with deoxyribonucleic acid in solution.
    Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2012
    Co-Authors: Khatereh Khorsandi, Azra Rabbani-chadegani
    Abstract:

    Abstract Chromium is a toxic and carcinogenic compound widely distributed in environment. In the present study we have investigated the interaction of chromium oxide with DNA employing UV/vis and Fluorescence spectroscopy as well as Circular dichroism, thermal denaturation, retardation polyacrylamide gel electrophoresis and DNA-cellulose affinity techniques. The results showed that the binding of chromium oxide to DNA is concentration dependent; at low concentration shows a little effect but ant higher concentrations (>100 μg/ml) reduced the absorbance at 260 and 210 nm producing hypochromicity. Also λmax of the metal at 210, 260 and 350 nm was reduced. DNA chromophores quenched with the chromium oxide and decreased Fluorescence Emission Intensity. Upon binding of the metal to DNA the elliplicity at positive extreme was decreased (275 nm) and increased the ellipticity of the DNA at negative extreme 245 nm. Thermal denaturation profile of DNA shifted to higher degrees upon chromium oxide binding which accompanied by hypochromicity. Also, affinity of chromium oxide to double stranded DNA was higher than single stranded DNA. From the result it is concluded that chromium oxide interacts with DNA via two modes of interaction inducing structural changes and DNA compaction evidence providing chromium oxide genotoxicity.

Yang Lu-zhao - One of the best experts on this subject based on the ideXlab platform.

  • Synthesis and characterization of water-soluble polyaniline films
    Synthetic Metals, 2011
    Co-Authors: Liang Shao, Huixia Feng, Guohong Zhang, Yang Lu-zhao
    Abstract:

    Abstract Water-soluble polyaniline (PANI) films were synthesized by using poly(2-acrylamido-2-methyl propanesulphonic acid) (PAMPS) as a water-soluble dopant. The aqueous solution conductivities of PANI/PAMPS films were in the range of 10 −1 to 10 0  mS/cm which were increased compared with PAMPS films aqueous solution. The structure and microstructure characteristics of PANI/PAMPS films which varied greatly with different molar ratios of aniline/AMPS were investigated by SEM, UV–vis absorption spectroscopy and XRD analysis. Moreover, the photoluminescence properties of PANI/PAMPS films were studied, and water-soluble PANI having appropriate size fitted to the increase of Fluorescence Emission Intensity. PANI/PAMPS films were also investigated by FTIR spectroscopy and TG analysis.

Zohreh Zahraei - One of the best experts on this subject based on the ideXlab platform.

  • A comparison of the effect of anticancer drugs, idarubicin and adriamycin, on soluble chromatin
    European Journal of Pharmacology, 2007
    Co-Authors: Zohreh Zahraei, Azra Rabbani-chadegani
    Abstract:

    Abstract The biological activity of an anticancer agent is related to its physicochemical interaction with biological receptors. In the present study we have investigated and compared the affinity and mode of action of two potent anticancer drugs, adriamycin and idarubicin on soluble chromatin using ultraviolet/visible and Fluorescence spectroscopy, hydroxyapatite (HAP) chromatography and gel electrophoresis techniques. The results show that addition of various concentrations of drugs to chromatin solution individually, reduced both absorbance and Fluorescence Emission Intensity of chromatin and precipitated it in a dose dependent manner, however, the extent of reduction was different for two drugs used. This effect was also observed on the histone gel patterns of the drug treated samples revealing that the chromatin is less affected by idarubicin compared to adriamycin implying higher aggregation of chromatin with the former. As hydroxyapatite chromatograms show, histone H1 represented the highest drug binding activity. The results suggest that although adriamycin and idarubicin are both grouped anthracycline antibiotic anticancer drugs, they differ considerably on their binding affinity to cellular chromatin.

S.r. Kasturi - One of the best experts on this subject based on the ideXlab platform.

  • Interaction of Ant-ATP with tubulin: evidence for ATP competition for the GTP E-site on tubulin.
    Archives of Biochemistry and Biophysics, 1993
    Co-Authors: S.r. Kasturi
    Abstract:

    Abstract The interaction of the ribose-moditied ATP analogue 3′- O -anthraniloyl adenosine 5′-triphosphate (Ant-ATP) with tubulin has been studied using steady-state Fluorescence techniques. This analogue inhibits the polymerization of tubulin induced by ATP or GTP. When this analogue binds to tubulin, an increase in the Fluorescence Intensity of the analogue and a blue shift of about 10 nm in the Emission maximum have been observed. It has been found that Ant-ATP binds to tubulin at a single binding site in the hydrophobic region with a dissociation constant of 0.5-1.0 μM. It has been possible to restore the Fluorescence Emission Intensity of the tubulin-bound analogue to that of the free ligand with a concomitant shift in the wavelength of Emission maximum to that of the free analogue by displacing the analogue with ATP or GTP. These results can be interpreted to suggest that ATP and GTP compete for the Ant-ATP binding site and that ATP binds at the GTP exchangeable site (E-site).