Abstract：
Polycyclic aromatic hydrocarbons found in crude oil can impair fish health following sublethal exposure. However, the dysbiosis of microbial communities within the fish host and influence it has on the toxic response of fish following exposure has been less characterized, particularly in marine species. To better understand the effect of dispersed crude oil (DCO) on juvenile Atlantic cod (Gadus morhua) microbiota composition and potential targets of exposure within the gut, fish were exposed to 0.05 ppm DCO for 1, 3, 7, or 28 days and 16 S metagenomic and metatranscriptomic sequencing on the gut and RNA sequencing on intestinal content were conducted. In addition to assessing species composition, richness, and diversity from microbial gut community analysis and transcriptomic profiling, the functional capacity of the microbiome was determined. Mycoplasma and Aliivibrio were the two most abundant genera after DCO exposure and Photobacterium the most abundant genus in controls, after 28 days. Metagenomic profiles were only significantly different between treatments after a 28-day exposure. The top identified pathways were involved in energy and the biosynthesis of carbohydrates, fatty acids, amino acids, and cellular structure. Biological processes following fish transcriptomic profiling shared common pathways with microbial functional annotations such as energy, translation, amide biosynthetic process, and proteolysis. There were 58 differently expressed genes determined from metatranscriptomic profiling after 7 days of exposure. Predicted pathways that were altered included those involved in translation, signal transduction, and Wnt signaling. EIF2 signaling was consistently dysregulated following exposure to DCO, regardless of exposure duration, with impairments in IL-22 signaling and spermine and spermidine biosynthesis in fish after 28 days. Data were consistent with predictions of a potentially reduced immune response related to gastrointestinal disease. Herein, transcriptomic-level responses helped explain the relevance of differences in gut microbial communities in fish following DCO exposure.
摘要：
原油中发现的多环芳烃在亚致死暴露后会损害鱼类的健康。然而,鱼类宿主内微生物群落的生态失调及其对鱼类暴露后的毒性反应的影响较少，特别是在海洋物种中。为了更好地了解分散原油（DCO）对幼年大西洋鳕鱼（Gadusmorhua）微生物群组成和肠道内潜在暴露目标的影响，将鱼暴露于0.05ppmDCO1、3、7或28天，并对肠道进行16S宏基因组和基因组测序，并对肠道内容物进行RNA测序。除了评估物种组成，丰富,以及微生物肠道群落分析和转录组学分析的多样性，确定了微生物组的功能能力。在DCO暴露后，支原体和Aliivibrio是最丰富的两个属，而在对照中，光细菌是最丰富的属。28天后在28天暴露后的治疗之间，宏基因组谱仅有显着差异。确定的主要途径涉及能量和碳水化合物的生物合成，脂肪酸，氨基酸,和细胞结构。鱼类转录组学分析后的生物过程与微生物功能注释共享共同的途径，例如能量，翻译,酰胺生物合成过程，和蛋白水解。暴露7天后，从元转录组学分析确定了58个不同表达的基因。被改变的预测途径包括那些参与翻译的途径，信号转导，和Wnt信号。暴露于DCO后，EIF2信号始终失调，无论暴露持续时间如何，28天后，鱼的IL-22信号传导以及精胺和亚精胺生物合成受损。数据与与胃肠道疾病相关的潜在免疫反应降低的预测一致。在这里，转录组水平的响应有助于解释DCO暴露后鱼类肠道微生物群落差异的相关性。
