• Title/Summary/Keyword: Microcalorimetric analysis

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A combined approach to evaluate activity and structure of soil microbial community in long-term heavy metals contaminated soils

  • Wang, Tianqi;Yuan, Zhimin;Yao, Jun
    • Environmental Engineering Research
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    • v.23 no.1
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    • pp.62-69
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    • 2018
  • In the present study, long-term heavy metals (HMs) contaminated soil samples from a well-known Pb/Zn smelting area in the southwest of China were collected, and physicochemical and biological characteristics of these samples were evaluated. Soil samples contained different concentrations of HMs, namely Pb, Zn, Cu, and Cd. Enzyme activity analyses combined with microcalorimetric analysis were used for soil microbial activity evaluation. Results showed that two soil samples, containing almost the highest concentrations of HMs, also shared the greatest microbial activities. Based on correlation coefficient analysis, high microbial activity in heavily HMs contaminated soil might be due to the high contents of soil organic matter and available phosphorus in these samples. High-throughput sequencing technique was used for microbial community structure analysis. High abundance of genera Sphingomonas and Thiobacillus were also observed in these two heavily contaminated soils, suggesting that bacteria belonging to these two genera might be further isolated from these contaminated soils and applied for future studies of HMs remediation. Results of present study would contribute to the evaluation of microbial communities and isolation of microbial resources to remediate HMs pollution.

An Isothermal Titration Microcalorimetric Study on the Interaction of Three Water-Soluble Porphyrins with Histone H2B

  • Bordbar, A.K.;Ghaderi, A.R.;Safaei, E.;Tangestaninejad, S.;Eslami, A.;Saboury, A.A.;Moosavi Movahedi, A.A.
    • Bulletin of the Korean Chemical Society
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    • v.24 no.5
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    • pp.547-551
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    • 2003
  • In the present work, the interaction of three water soluble porphyrins, tetra(p-trimethyle) ammonium phenyl porphyrin iodide (TAPP) as a cationic porphyrin, tetra sodium meso-tetrakis (p-sulphonato phenyle) porphyrin (TSPP) as an anionic porphyrin and manganese tetrakis (p-sulphonato phenyl) porphinato acetate (MnTSPP) as a metal porphyrin, with histone H₂B have been studied by isothermal titration microcalorimetry at 8 mM phosphate buffer, pH 6.8 and 27 °C. The values of binding constant, entropy, enthalpy and Gibbs free energy changes for binding of the first MnTSPP, and first and second TSPP and TAPP molecules were estimated from microcalorimetric data analysis. The results represent that the process is both entropy and enthalpy driven and histone induces self-aggregation of the porphyrins. The results indicate that both columbic and hydrophobic interactions act as self-aggregation driving forces for the formation of aggregates around histone.