Zacchi Flávia Lucena, de Lima Daína, Flores-Nunes Fabrício, Mattos Jacó Joaquim, Lüchmann Karim Hahn, de Miranda Gomes Carlos Henrique Araújo, Bícego Márcia Caruso, Taniguchi Satie, Sasaki Silvio Tarou, Dias Bainy Afonso Celso
Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry - LABCAI, Federal University Santa Catarina, Florianópolis, Brazil.
Aquaculture Pathology Research Center - NEPAQ, Federal University of Santa Catarina, Florianópolis, Brazil.
Aquat Toxicol. 2017 Feb;183:94-103. doi: 10.1016/j.aquatox.2016.12.016. Epub 2016 Dec 21.
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 PHE 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.
来自河口的广盐性动物，如巴西牡蛎（Crassostrea brasiliana），展现出适应盐度变化的生理机制。这些生态系统不断接收来自城市地区的外源化合物输入，包括多环芳烃（PAHs），如菲（PHE）。为了了解盐度对暴露于PHE的巴西牡蛎分子反应的影响，将牡蛎在不同盐度（35、25和10）下驯化15天，然后暴露于100μg/L的PHE中24小时和96小时。对照组保持在相同盐度但不接触PHE。对牡蛎进行化学分析采样，并切除鳃用于通过qPCR进行mRNA定量。测量了不同基因的转录水平，包括一些参与氧化应激途径、外源化合物生物转化系统的I相和II相、氨基酸代谢、脂肪酸代谢以及芳烃受体核转运体假定基因。与对照组相比，在盐度为10时暴露于PHE的牡蛎中观察到类磺基转移酶基因（SULT-like）的转录水平更高（24小时和96小时）；细胞色素P450同工型（CYP2AU1、CYP2-like1）在暴露24小时的牡蛎中升高更明显，而CYP2-like2在盐度为10时暴露于PHE 96小时的牡蛎中相对于对照组升高更明显。这些结果可能与低渗应激下PHE解毒所需的I相生物转化活性增强有关。与盐度为25和/或35的生物体相比，盐度为10的牡蛎中类CAT、类SOD、类GSTm（96小时）和类GSTΩ（24小时）的转录水平更高，这可能与活性氧生成增加有关。这些基因的转录不受PHE暴露的影响。氨基酸代谢相关基因（24小时的类GAD、类GLYT、96小时的类ARG以及24小时和96小时的类TAUT）在暴露于不同盐度的生物体中也显示出不同的转录水平，表明它们在牡蛎适应盐度方面的重要作用，而不受这些PHE水平暴露的影响。
