RESUMO
Isolated organs and cell lines from zebrafish exhibit circadian oscillations in clock gene expression that can be entrained to a 24-h light/dark cycle. The mechanism underlying this cellular photosensitivity is unknown. We report the identification of a novel opsin family, tmt-opsin, that has a genomic structure characteristic of vertebrate photopigments, an amino acid identity equivalent to the known photopigment opsins, and the essential residues required for photopigment function. Significantly, tmt-opsin is expressed in a wide variety of neural and non-neural tissues, including a zebrafish embryonic cell line that exhibits a light entrainable clock. Collectively the data suggest that tmt-opsin is a strong candidate for the photic regulation of zebrafish peripheral clocks.
Assuntos
Relógios Biológicos/fisiologia , Linhagem Celular/metabolismo , Regulação da Expressão Gênica/genética , Fotoperíodo , Opsinas de Bastonetes/isolamento & purificação , Takifugu/metabolismo , Peixe-Zebra/metabolismo , Sequência de Aminoácidos/genética , Animais , Sequência de Bases/genética , Encéfalo/metabolismo , Linhagem Celular/citologia , DNA Complementar/análise , DNA Complementar/genética , Evolução Molecular , Biblioteca Genômica , Dados de Sequência Molecular , Filogenia , Opsinas de Bastonetes/genética , Homologia de Sequência de Aminoácidos , Takifugu/genética , Vísceras/metabolismo , Peixe-Zebra/genéticaRESUMO
Pollution history has often been proposed to explain site-dependent bioremediation efficiencies, but this hypothesis has been poorly explored. Here, bacteria and their heterotrophic nanoflagellates (HNF) predators originating from pristine and chronically oil-polluted coastal sites were subjected to crude oil ± nutrients or emulsifier amendments. The addition of crude oil had a more visible effect on bacteria originating from the pristine site with a higher increase in the activity of given OTU and inactivation of other petroleum-sensitive bacteria, as revealed by DNA and RNA-based comparison. Such changes resulted in a delay in microbial growth and in a lower bacterial degradation of the more complex hydrocarbons. Biostimulation provoked a selection of different bacterial community assemblages and stirred metabolically active bacteria. This resulted in a clear increase of the peak of bacteria and their HNF predators and higher oil degradation, irrespective of the pollution history of the site.