RESUMO
Metals are subject to internal subcellular compartmentalization, altering their bioavailability. Thus, subcellular metal assessments are crucial in biomonitoring efforts. Metal distribution in three subcellular fractions (insoluble - ISF, thermolabile - TLF and thermostable - TSF) were determined by ICP-MS in Steno bredanensis specimens from Southeastern Brazil. Associations between metals, metallothionein (MT) and reduced glutathione (GSH) were also investigated. Differential metal-detoxification mechanisms were observed. MT detoxification was mostly noted for As, Cd, and Pb, while Cu, Cr, Hg, Ni, Se and Ti displayed lower MT-associations. Fe, Zn and Se, on the other hand, were poorly associated to MT, and mostly present in the ISF, indicating low bioavailability. This is the first report on subcellular Sn and Ti distribution in cetaceans and the first in this species in Brazil. Potential protective roles of essential metals against toxic elements are postulated. This study indicates that important biochemical detoxification information is obtained through subcellular fraction analyses in marine mammals.
Assuntos
Golfinhos/metabolismo , Monitoramento Ambiental/métodos , Metalotioneína/metabolismo , Metais/metabolismo , Frações Subcelulares/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Brasil , Glutationa/metabolismo , Inativação Metabólica , Metais Pesados/análise , Estanho/metabolismo , Titânio/metabolismoRESUMO
Tin or stannous (Sn(2+)) compounds are used as catalysts, stabilizers in plastic industries, wood preservatives, agricultural biocides and nuclear medicine. In order to verify the Sn(2+) up-take and toxicity in yeast cells we utilized a multi-elemental analysis known as particle-induced X-ray emission (PIXE) along with cell survival assays and quantitative real-time PCR. The detection of Sn(2+) by PIXE was possible only in yeast cells in stationary phase of growth (STAT cells) that survive at 25mM Sn(2+) concentration. Yeast cells in exponential phase of growth (LOG cells) tolerate only micro-molar Sn(2+) concentrations that result in intracellular concentration below of the method detection limit. Our PIXE analysis showed that STAT XV185-14c yeast cells demonstrate a significant loss of intracellular elements such as Mg, Zn, S, Fe and an increase in P levels after 1h exposure to SnCl(2). The survival assay showed enhanced tolerance of LOG yeast cells lacking the low-affinity iron and zinc transporters to stannous treatment, suggesting the possible involvement in Sn(2+) uptake. Moreover, our qRT-PCR data showed that Sn(2+) treatment could generate reactive oxygen species as it induces activation of many stress-response genes, including SOD1, YAP1, and APN1.
Assuntos
Proteínas de Transporte/genética , Poluentes Ambientais/toxicidade , Estanho/toxicidade , Leveduras/genética , Adaptação Fisiológica , Proteínas de Transporte/metabolismo , Poluentes Ambientais/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Expressão Gênica/efeitos dos fármacos , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Superóxido Dismutase-1 , Estanho/metabolismo , Leveduras/efeitos dos fármacos , Leveduras/metabolismoRESUMO
The study of the labelling of planaria with 99mTc shows that the incorporation of radioactivity in this platyhelminth increases with an increase sin SnCl2 concentration from 0.13 to 1.3 micronM, reaching a plateau in the range of 1.3-130 micronM then decreasing with 1300 microng. At concentrations of 1.3 and 13 microngM SnCl2, a stronger binding of 99mTc was obtained. The biological viability of the labelled planaria was not altered when the described methodology was used. The advantage of this new labelling technique is that it is possible to obtain a platyhelminth preparation labelled with a radionuclide that is very cheap, is easily available and is a gamma emitter with a photon energy of 140 KeV
Assuntos
Planárias/fisiologia , Tecnécio , Estanho/metabolismoRESUMO
The study of the labelling of planaria with 99mTc shows that the incorporation of radioactivity in this platyhelminth increases with an increase in SnCl2 concentration from 0.13 to 1.3 microM, reaching a plateau in the range of 1.3-130 microM then decreasing with 1300 microM. At concentrations of 1.3 and 13 microM SnCl2, a stronger binding of 99mTc was obtained. The biological viability of the labelled planaria was not altered when the described methodology was used. The advantage of this new labelling technique is that it is possible to obtain a platyhelminth preparation labelled with a radionuclide that is very cheap, is easily available and is a gamma emitter with a photon energy of 140 keV.