RESUMEN
Chelates of Gadolinium (Gd), a lanthanide metal, are employed as contrast agents for magnetic resonance imaging and are released into the aquatic environment where they are an emerging contaminant. We studied the effects of environmentally relevant Gd concentrations on the development of two phylogenetically and geographically distant sea urchin species: the Mediterranean Paracentrotus lividus and the Australian Heliocidaris tuberculata. We found a general delay of embryo development at 24h post-fertilization, and a strong inhibition of skeleton growth at 48h. Total Gd and Ca content in the larvae showed a time- and concentration-dependent increase in Gd, in parallel with a reduction in Ca. To investigate the impact of Gd on the expression of genes involved in the regulation of skeletogenesis, we performed comparative RT-PCR analysis and found a misregulation of several genes involved in the skeletogenic and left-right axis specification gene regulatory networks. Species-specific differences in the biomineralization response were evident, likely due to differences in the skeletal framework of the larvae and the amount of biomineral produced. Our results highlight the hazard of Gd for marine organisms.
Asunto(s)
Anthocidaris/efectos de los fármacos , Calcio/metabolismo , Gadolinio/toxicidad , Paracentrotus/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Animales , Anthocidaris/clasificación , Anthocidaris/crecimiento & desarrollo , Desarrollo Embrionario/efectos de los fármacos , Factores de Crecimiento de Fibroblastos/genética , Factores de Crecimiento de Fibroblastos/metabolismo , Larva/efectos de los fármacos , Larva/genética , Larva/metabolismo , Paracentrotus/clasificación , Paracentrotus/crecimiento & desarrollo , Filogenia , Reacción en Cadena en Tiempo Real de la Polimerasa , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
The whole mitochondrial genome sequence of sea urchin Heliocidaris crassispina of the family Echinometridae is determined for the first time in this study. The circular mitogenome (15,702 bp) consists of typical Camarodonta gene order and its components including 2 rRNA, 22 tRNA, 13 protein-coding genes and a control region. Phylogenetic analysis based on the 13 concatenated protein-coding gene sequences shows that H. crassispina is closer to the species of Strongylocentrotidae than Parechinidae, but the separation between H. crassispina and the Strongylocentrotid species occurred early in their evolution. The complete mitochondrial genome presented in this study is useful for inferring the phylogenetic relationship among the families of Echinidea sea urchins.