title: Transcriptional changes in oysters Crassostrea brasiliana exposed to phenanthrene at different salinities.
abstract: Euryhaline animals from estuaries, such as the oyster Crassostrea brasiliana, show physiological mechanisms of adaptation to tolerate salinity changes. These ecosystems receive constant input of xenobiotics from urban areas, including polycyclic aromatic hydrocarbons (PAHs), such as phenanthrene (PHE). In order to understand the influence of salinity on the molecular responses of C. brasiliana exposed to PHE, oysters were acclimatized to different salinities (35, 25 and 10) for 15days and then exposed to 100μgL-1PHE for 24h and 96h. Control groups were kept at the same salinities without PHE. Oysters were sampled for chemical analysis and the gills were excised for mRNA quantification by qPCR. Transcript levels of different genes were measured, including some involved in oxidative stress pathways, phases I and II of the xenobiotic biotransformation systems, amino acid metabolism, fatty acid metabolism and aryl hydrocarbon receptor nuclear translocator putative gene. Higher transcript levels of Sulfotransferase-like gene (SULT-like) were observed in oysters exposed to PHE at salinity 10 compared to control (24h and 96h); cytochrome P450 isoforms (CYP2AU1, CYP2-like1) were more elevated in oysters exposed for 24h and CYP2-like2 after 96h of oysters exposed to PHE at salinity 10 compared to control. These results are probably associated to an enhanced Phase I biotransformation activity required for PHE detoxification under hyposmotic stress. Higher transcript levels of CAT-like, SOD-like, GSTm-like (96h) and GSTΩ-like (24h) in oysters kept at salinity 10 compared to organisms at salinities 25 and/or 35 are possibly related to enhaced ROS production. The transcription of these genes were not affected by PHE exposure. Amino acid metabolism-related genes (GAD-like (24h), GLYT-like, ARG-like (96h) and TAUT-like at 24h and 96h) also showed different transcription levels among organisms exposed to different salinities, suggesting their important role for oyster salinity adaptation, which is not affected by exposure to these levels of PHE.
authors.affiliation: Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry - LABCAI, Federal University Santa Catarina, Florianópolis, Brazil.
authors.forename: Flávia Lucena
authors.initials: FL
authors.lastname: Zacchi
authors.affiliation: Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry - LABCAI, Federal University Santa Catarina, Florianópolis, Brazil.
authors.forename: Daína
authors.initials: D
authors.lastname: de Lima
authors.affiliation: Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry - LABCAI, Federal University Santa Catarina, Florianópolis, Brazil.
authors.forename: Fabrício
authors.initials: F
authors.lastname: Flores-Nunes
authors.affiliation: Aquaculture Pathology Research Center - NEPAQ, Federal University of Santa Catarina, Florianópolis, Brazil.
authors.forename: Jacó Joaquim
authors.initials: JJ
authors.lastname: Mattos
authors.affiliation: Laboratory of Biochemistry and Molecular Biology - LBBM, Fishery Engineering Department, Santa Catarina State University, Laguna, Brazil.
authors.forename: Karim Hahn
authors.initials: KH
authors.lastname: Lüchmann
authors.affiliation: Laboratory of Marine Mollusks - LMM, Federal University of Santa Catarina, Florianópolis, Brazil.
authors.forename: Carlos Henrique Araújo
authors.initials: CHA
authors.lastname: de Miranda Gomes
authors.affiliation: Laboratory of Marine Organic Chemistry - LABQOM, Oceanographic Institute, University of São Paulo, São Paulo, Brazil.
authors.forename: Márcia Caruso
authors.initials: MC
authors.lastname: Bícego
authors.affiliation: Laboratory of Marine Organic Chemistry - LABQOM, Oceanographic Institute, University of São Paulo, São Paulo, Brazil.
authors.forename: Satie
authors.initials: S
authors.lastname: Taniguchi
authors.affiliation: Laboratory of Marine Organic Chemistry - LABQOM, Oceanographic Institute, University of São Paulo, São Paulo, Brazil.
authors.forename: Silvio Tarou
authors.initials: ST
authors.lastname: Sasaki
authors.affiliation: Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry - LABCAI, Federal University Santa Catarina, Florianópolis, Brazil. Electronic address: afonso.bainy@ufsc.br.
authors.forename: Afonso Celso
authors.initials: AC
authors.lastname: Dias Bainy
mesh_terms: D000818:Animals; D001711:Biotransformation; D049896:Crassostrea / Q000187:drug effects* / Q000235:genetics; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D063366:Estuaries; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D010616:Phenanthrenes / Q000633:toxicity*; D054712:Salinity; D014158:Transcription, Genetic / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015262:Xenobiotics / Q000378:metabolism
chemical_list: D010616:Phenanthrenes; D014874:Water Pollutants, Chemical; D015262:Xenobiotics; C031181:phenanthrene; D003577:Cytochrome P-450 Enzyme System
keywords: Estuaries; Mangrove oyster; PAHs; Phenanthrene; Salinity; qPCR