RESUMO
Beclin 1 plays an important role in autophagy and apoptosis which are well documented in mammals. However, relevant reports are rare in fish. This study characterized Beclin 1 of the rare minnow Gobiocypris rarus (rmBeclin 1), which encodes a peptide of 447 amino acids using RT-PCR and RACE. The deduced peptide showed 96.4 and 80.8% similarity to Beclin 1 of common carp and human, respectively. Semiquantitative RT-PCR revealed that rmBeclin 1 was ubiquitously expressed in all tested tissues of male and female fish in all developmental stages, even unfertilized eggs. RT-qPCR revealed that rmBeclin 1 mRNA transcripts were significantly up-regulated in gills after a 12 h treatment with waterborne CdCl2 but were decreased thereafter. However, rmBeclin 1 expression was decreased in the brain, but it was not significantly changed in other tissues. Subchronic CdCl2 exposure significantly increased rmBeclin 1 in the brain, but it distinctly decreased rmBeclin 1 in the gill and hepatopancreas. A dose-dependent effect was not observed in mature fish treated for 96 h, but a dose-dependent effect existed in immature fish treated for 10 days. Longer treatment (10 day) caused a significantly higher expression of rmBeclin 1 in the larvae groups. These data suggest that alterations in rmBeclin 1 after CdCl2 exposure are tissue-specific and time-related and that the dose-dependent effect was restricted to a certain concentration range and exposure time.
Assuntos
Proteínas Reguladoras de Apoptose/genética , Cádmio/toxicidade , Cyprinidae/genética , Proteínas de Peixes/genética , Expressão Gênica/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Sequência de Aminoácidos , Animais , Sequência de Bases , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , DNA Complementar/genética , Relação Dose-Resposta a Droga , Feminino , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Hepatopâncreas/efeitos dos fármacos , Hepatopâncreas/metabolismo , Masculino , Dados de Sequência Molecular , RNA Mensageiro/metabolismoRESUMO
The toxic effects of CdSe/ZnS QDs on zebrafish (Danio rerio) embryos at different developmental stages were investigated in this study. The voluntary movement frequency, body length, hatching rate, mortality and malformation rate, SOD activities, MDA contents, mRNA expression of metallothionein (MT) and heat stress protein 70 (Hsp70) were used as indicators. The results showed that the EC50 was 316.994 nmol x L(-1) for zebrafish embryos (72 hpf) when exposed to CdSe/ZnS QDs. After the CdSe/ZnS QDs exposure, the embryos showed a significant increase in mortality and malformation rate, a decrease in hatching rate and body length, an advance in hatching time, and a changing in the spontaneous movement frequency, and many other toxic effects, such as the condensation of embryonic eggs, the formation of pericardial cysts and curvature of the spine. Moreover, it was found that the MDA contents in the embryos in CdSe/ZnS QDs groups were significantly increased, and the SOD activities were changed. In addition, the mRNA expression level of MT and Hsp70 were up-regulated. All the information suggests that exposure of CdSe/ZnS QDs can cause toxic effects on zebrafish embryos, and the effects may be related to the releasing of Cd2+, particle size and oxidative stress.
