RESUMEN
The production capacity and yield of neodymium (Nd) in China have ranked the first in the world. Because of its unique biophysical and biochemical properties, Nd compounds have entered into the agricultural environment greatly to promote plant growth. Mitochondria play a crucial role in respiration and metabolism during the growth of plants. However, little is known about the mechanism by which Nd act at the mitochondrial level in plant cells. In this study, rice mitochondrial swelling, collapsed transmembrane potential and decreased membrane fluidity were examined to be important factors for mitochondria permeability transition pore (mPTP) opening induced by Nd(III). The protection of cyclosporin A (CsA) and dithiothreitol (DTT) could confirm that Nd(III) could trigger mPTP opening. Additionally, mitochondrial membrane breakdown observed by TEM and the release of cytochrome c (Cyt c) could also elucidate the mPTP opening from another point of view. At last, the study showed that Nd(III) could restrain the mitochondrial membrane lipid peroxide, so it might interact with anionic lipid too. This detection will be conductive to the safe application of Nd compounds in agriculture and food industry.
Asunto(s)
Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Neodimio/farmacología , Oryza/efectos de los fármacos , Oryza/metabolismo , Citocromos c/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Fluidez de la Membrana/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Microscopía , Mitocondrias/ultraestructura , Dilatación Mitocondrial/efectos de los fármacos , Permeabilidad/efectos de los fármacos , Análisis EspectralRESUMEN
Antibacterial activities of novel organoarsenic compounds As(III)-containing Schiff bases on Escherichia coli (CCTCCAB91112) were investigated by microcalorimetry in this study. The experimental result showed that the arsenic(III)-containing Schiff bases at micromolar concentration exhibit strong inhibition on the E. coli. Specifically, the growth rate constant k decreased, and the generation time t G and the inhibitory ratio I (percentage) increased with the increased dose of the arsenicals as inhibitors. All of the arsenicals display the feature of considerable lag phase inhibition on the cell growth. The compound 4-(4-bromobenzaliminyl)phenylarsenoxide makes the lag phase of E. coli cell growth cycles to reach 650 min at 5 µmol/L. The compounds with donating electron groups at aromatic ring B have lower IC50 to present higher antibacterial activity. The compound 4-(4-hydroxyl-3-methoxylbenzaliminyl)phenylarsenoxide has the lowest IC50 (1.82 µmol/L) to show the strongest antibacterial activity among them.
Asunto(s)
Antibacterianos/farmacología , Arsenicales/farmacología , Calorimetría/métodos , Escherichia coli/efectos de los fármacos , Compuestos Orgánicos/farmacología , Evaluación Preclínica de Medicamentos , Pruebas de Sensibilidad MicrobianaRESUMEN
Cerium has been widely used as fertilizer and feed additives in agriculture, but it might finally impair human health by food chain accumulation with its dosage increased in environmental and crops samples. To resolve the conflict, we investigated the effects of Ce(III) on isolated rice mitochondrial permeability transition (MPT) by examining mitochondrial swelling, transmembrane potential, membrane fluidity with spectroscopy, and observing the mitochondrial ultrastructure, meanwhile, the interaction site(s) and mechanism between Ce(III) and mitochondria were also studied. The results showed that the low level of Ce(III) had little effect on rice MPT, however, the higher level of Ce(III) could induce rice MPT, and the thiol (-SH) groups of membrane proteins (defined as "S" site) matched by Ce(III)-triggered rice MPT pore opening.
Asunto(s)
Cerio/farmacología , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Oryza/efectos de los fármacos , Oryza/metabolismo , Fluidez de la Membrana/efectos de los fármacos , Potenciales de la Membrana/efectos de los fármacos , Microscopía Electrónica de Transmisión , Mitocondrias/ultraestructura , Proteínas de Transporte de Membrana Mitocondrial , Poro de Transición de la Permeabilidad Mitocondrial , Dilatación Mitocondrial/efectos de los fármacos , Oryza/ultraestructuraRESUMEN
Mitochondria were isolated from the hybrid rice Xiangzaoxian 31, then the effects of low and high concentrations of Ce (Ш) on metabolism of mitochondria fed by pyruvate were investigated respectively, by microcalorimetry and oxygen electrode method The thermogenic curve of mitochondria without Ce (Ш) could be divided into three parts: activity recovery phase, stationary phase and decline phase. And the thermokinetic parameters have been calculated through the metabolic thermogenic curves. With addition of different concentrations of Ce (Ш), the results demonstrated that low levels of cerium ion stimulated the metabolic activity of energized mitochondria and the inhibition was discovered with high concentrations of Ce (Ш). At the same time, it is shown that the effect in respiration correspond to the effect on mitochondrial metabolism on addition of different concentrations of Ce (Ш). Moreover, the addition of low and high concentrations of Ce (Ш) had no obvious effect on the total heat output (Q). The concentration-dependent effect of Ce (Ш) on metabolism of mitochondria is similar to plant growth response to rare earth elements (Hormesis effect).
Asunto(s)
Cerio/metabolismo , Mitocondrias/metabolismo , Oryza/metabolismo , Piruvatos/metabolismo , Calorimetría , Fertilizantes/análisisRESUMEN
Microcalorimetry was employed to investigate the action of Li(I) to aquatic ecosystem from the point view of bioenergetics. Tetrahymena thermophila BF5 was chosen as the model organism. The power-time curves of T. thermophila BF5 growth metabolism in the absence and presence of Li(I) were obtained. The corresponding thermokinetic parameters were derived. The generation time was calculated as 592.3 min, which was consistent with the biomass values. Low concentration of Li(I) (1-20 mmol l-1) stimulated the growth of T. thermophila BF5, whereas the inhibition effect was observed in high concentration (30-100 mmol l-1). The value of IC50 was 52.8 mmol l-1. In the concentration range of 30-100 mmol l-1, the growth rate constants (k) and the maximum heat out power (P max) decrease with the concentration of Li(I), whereas the heat output (Q) increases slightly compared to the control. Other than the classic mechanism of inositol-phosphate cycle, the involvement of mitochondria mechanism was discussed and suggested.
Asunto(s)
Cloruro de Litio/farmacología , Tetrahymena thermophila/efectos de los fármacos , Animales , Calorimetría/métodos , Tetrahymena thermophila/crecimiento & desarrollo , TermodinámicaRESUMEN
The effect of Li(I) on the metabolism of mitochondria isolated from Carassius auratus liver tissue was investigated by microcalorimetric method to provide evidence for mitochondria hypothesis of bipolar disorder (BPD) and to explore therapeutic mechanism of drug for treatment of BPD. Obvious stimulation induced by Li(I) on mitochondria metabolism was reflected by power-time (P-t) curves. The power-time curves of hepatic mitochondria metabolism without Li(I) could be divided into four parts: lag phase, active recovery phase, stationary phase, and decline phase. When Li(I) was added, the second heat peak occurred in a concentration-dependent sequence. Considering the first heat peak on the P-t curves, Li(I) in the range of therapeutic and lower concentration induced slight alterations in comparison with the characteristic heat peak observed in the control. However, Li(I) above the therapeutic concentration resulted in significant changes. Heat output increased with the concentration of Li(I), but the rate constant (k2) and the maximum heat power (Pmax2) for the second heat peak reached maximum value in the range of therapeutic concentration. Mechanism of activation of mitoKatp was suggested and discussed.