Antibacterial Effects of a Monoporphyrinato Ytterbium(III) Complex and Its Free Components on <i>Staphylococcus aureus</i> as Determined by Stop‐Flow Microcalorimetry

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The antibacterial activities towards Escherichia coli of two cationic Yb(III)-monoporphyrin complexes, [Yb(III)(TMP)(H2O)3]Cl (1) and [Yb(III)(TTP)(H2O)3]Cl (2), were investigated at the cellular and sub-cellular levels. The biological effects of the complexes on the growth of E. coli were evaluated by microcalorimetry and by analysis of the resulting metabolic thermogenic curves, from which IC50 values and metabolic parameters such as growth rate and generation time were derived. At the subcellular level, DNA-binding experiments were performed by means of UV/VIS- and fluorescence-titration experiments, as well as by near-infrared (NIR) emission, which revealed that 1 and 2 strongly bind to herring-sperm DNA (HS-DNA), though by different binding modes.

Section: Results Andmentioning

confidence: 99%

Section: Results Andmentioning

confidence: 99%

“…The calorimeter and its operation have been described in detail in one of our previous reports [9]. Here, we used the ampoule method [26].…”

Section: Experimental Partmentioning

confidence: 99%

Section: Experimental Partmentioning

confidence: 99%

“…E. coli (CCTCC HB101) was provided by the China Center of Type Culture Collection, Wuhan University, P. R. China. LB Culture medium was prepared as described in [9].…”

Section: Experimental Partmentioning

confidence: 99%

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Microcalorimetric and Spectroscopic Investigation of the Antibacterial Properties of Cationic Ytterbium(III)–Porphyrin Complexes Lacking Charged Peripheral Groups

Hou

Xue

Liu

et al. 2007

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Microcalorimetric Study of the Effect of Ce^III on Metabolic Activity of Mitochondria Isolated from Indice Rice 9311

Dai

Zhang

et al. 2008

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Rare earth elements (REEs) have beneficial influence on plant growth and are widely used in agriculture practice, but little is known about behavior of the REEs on mitochondria in plant cells. Thermogenic metabolic curves were determined by the ampoule method at 303 K using a TAM air isothermal microcalorimeter in mitochondria isolated from indice rice 9311 (Oryza sativa L.), and the effect of Ce(III) on mitochondrial metabolism was investigated. By analyzing the obtained heat flux curves, the crucial parameters such as activity recovery rate constant (k) and maximum heat power (P(m)) were investigated. Application of Ce3+ in concentrations ranging from 0 to 120 microg/ml significantly increased k and P(m) values, with the maximum reaching 261 and 180% of the control, respectively. Concentrations from 140 to 150 microg/ml had the opposite effect. These results were consistent with previous reports on the effects of REEs on plant growth. It was concluded that the Ce(III)-induced change of mitochondrial metabolic activity is a possible mechanism by which Ce(III) influenced indice rice 9311 growth.

Microcalorimetric Investigation on Effects of La^III on Metabolic Activity of Mitochondria Isolated from Hybrid Rice

Dai

Zhang

et al. 2008

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Rare earth elements (REEs) have beneficial influence on plant growth and are widely used in agriculture practice, but little is known about the behavior of the REEs in mitochondria of plant cell. Thermogenic metabolic curves were determined by the ampoule method at 303 K using a TAM air isothermal microcalorimeter in mitochondria isolated from hybrid rice Liangyoupeijiu (Oryza sativa L.), and the effect of La(III) on its mitochondrial metabolism was investigated. From the obtained heat flux curves, the crucial parameters including as activity recovery rate constant (k) and maximum heat power (P(max)) were determined. Application of La(3+) in concentrations ranging from 0 to 120 microg/ml significantly increased k and P(max) values with the high point reaching 346 and 222% of the control, respectively. Concentrations from 140-150 microg/ml had the opposite effect. These results were consistent with previous reports on the effects of REEs on plant growth. It was concluded that the La-induced change of mitochondrial metabolic activity is a possible mechanism by which La(III) ions influences hybrid rice growth.