Ertl Nicole G, O'Connor Wayne A, Brooks Peter, Keats Michael, Elizur Abigail
University of the Sunshine Coast, Sippy Downs, Queensland, Australia; Australian Seafood Cooperative Research Centre, South Australia, Australia.
University of the Sunshine Coast, Sippy Downs, Queensland, Australia; Department of Primary Industries, New South Wales, Australia. Electronic address: wayne.o'
Aquat Toxicol. 2016 Aug;177:136-45. doi: 10.1016/j.aquatox.2016.05.012. Epub 2016 May 24.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously detected in the water column, associated with particulate matter or in the tissue of marine organisms such as molluscs. PAH exposure and their resultant bioaccumulation in molluscs can cause a range of serious physiological effects in the affected animals. To examine the molecular response of these xenobiotics in bivalves, Sydney rock oysters (Saccostrea glomerata) were exposed to pyrene and fluoranthene for seven days. Chemical analysis of the soft-tissue of PAH stressed S. glomerata confirmed that pyrene and fluoranthene could be bioaccumulated by these oysters. RNA-Seq analysis of PAH-exposed S. glomerata showed a total of 765 transcripts differentially expressed between control and PAH-stressed oysters. Closer examination of the transcripts revealed a range genes encoding enzymes involved in PAH detoxification (e.g. cytochrome P450), innate immune responses (e.g. pathogen recognition, phagocytosis) and protein synthesis. Overall, pyrene and fluoranthene exposure appears to have resulted in a suppression of pathogen recognition and some protein synthesis processes, whereas transcripts of genes encoding proteins involved in clearance of cell debris and some transcripts of genes involved in PAH detoxification were induced in response to the stressors. Pyrene and fluoranthene exposure thus invoked a complex molecular response in S. glomerata, with results suggesting that oysters focus on removing the stressors from their system and dealing with the downstream effects of PAH exposure, potentially at the exclusion of other, less immediate concerns (e.g. protection from infection).
多环芳烃（PAHs）在水柱中普遍存在，与颗粒物相关，或存在于软体动物等海洋生物的组织中。PAHs暴露及其在软体动物中的生物累积会对受影响的动物造成一系列严重的生理影响。为了研究这些外源性物质在双壳贝类中的分子反应，将悉尼岩牡蛎（Saccostrea glomerata）暴露于芘和荧蒽中7天。对受PAHs胁迫的悉尼岩牡蛎软组织进行化学分析证实，这些牡蛎能够生物累积芘和荧蒽。对受PAHs暴露的悉尼岩牡蛎进行RNA测序分析表明，对照牡蛎和受PAHs胁迫的牡蛎之间共有765个转录本差异表达。对这些转录本的进一步研究发现了一系列编码参与PAHs解毒（如细胞色素P450）、先天免疫反应（如病原体识别、吞噬作用）和蛋白质合成的酶的基因。总体而言，芘和荧蒽暴露似乎导致了病原体识别和一些蛋白质合成过程的抑制，而编码参与清除细胞碎片的蛋白质的基因转录本以及一些参与PAHs解毒的基因转录本在应激源作用下被诱导。芘和荧蒽暴露因此在悉尼岩牡蛎中引发了复杂的分子反应，结果表明牡蛎专注于从其系统中清除应激源并应对PAHs暴露的下游影响，可能会排除其他不太紧迫的问题（如预防感染）。
