To obtain a deeper understanding of the transcriptomic responses to oil in southern flounder (Paralichthys lethostigma), we performed quantitative PCR and RNA sequencing on liver and gill tissue after a chronic exposure (35 days) to Deepwater Horizon crude oiled sediment and after a 30-day recovery period. We wanted to understand which specific genes are differentially expressed in liver and gill tissues directly after oiled sediment exposure and with the addition of a recovery period. Furthermore, we wanted to examine specific enriched pathways in these two tissues to determine the impact of exposure with and without a recovery period on biological processes (e.g. immune function). Liver and gill tissues were chosen because they represent two distinct organs that are highly important to consider when examining the impacts of oiled sediment exposure. The liver is the classic detoxification organ, while the gill is in direct contact with sediment in benthic fishes. Examination of these two tissues, therefore, generates a broad understanding of the transcriptomic consequences of oil exposure across an organism. Gene expression for interleukin 8 (il8) and interleukin 1B (il1β) was significantly increased versus control measurements for fish exposed to oiled sediments for 35 days in gill tissue. Hierarchical clustering of gene expression showed that tissue type was the main driver of gene expression (rather than treatment). The inclusion of a 30-day post-exposure recovery period showed a return of il8 and il1β gene expression in the gill to baseline expression levels. However, the recovery period increased the number of differentially expressed genes and significantly affected canonical pathways in both tissue types. Pathways related to cholesterol biosynthesis were significantly suppressed in oil-exposed flounder with a recovery period, but not in the exposed flounder without a recovery period. At the end of the exposure, 17 pathways were significantly affected in the gill, including thyroid hormone metabolism-related pathways, which were the most influenced. Liver tissue from the recovered fish had the greatest number of enriched pathways for any tissue or time point (187). Cellular and humoral immune response pathways were considerably impacted in the liver after the recovery period, suggesting that the immune system was attempting to respond to potential damage caused from the chronic oil exposure. Our results demonstrate that liver and gill tissues from southern flounder were differentially altered by Deepwater Horizon oiled sediment exposure and that a 30-day recovery period after exposure substantially shifted gene expression and canonical pathway profiles.

为了更深入地了解南部比目鱼（Paralichthys lethostigma）对油的转录组反应，我们在长期暴露于Deepwater Horizo​​n（35天）后对肝脏和g组织进行了定量PCR和RNA测序原油沉淀物，经过30天的恢复期。我们想了解在上油沉积物暴露后，加上恢复期后，哪些特定基因在肝脏和腮组织中差异表达。此外，我们想检查这两个组织中特定的富集途径，以确定有无恢复期的暴露对生物过程（例如免疫功能）的影响。选择肝和g组织是因为它们代表两个不同的器官，在检查油污沉积物暴露的影响时，非常重要的考虑因素。肝脏是经典的排毒器官，而ill与底栖鱼类的沉积物直接接触。因此，检查这两个组织 对整个生物体内的油脂接触产生的转录组后果有广泛的了解。白细胞介素8（与对照相比，在ill组织中暴露于上油沉积物35天的鱼的il8）和白介素1B（il1β）显着增加。基因表达的层次聚类表明组织类型是基因表达的主要驱动力（而不是治疗）。暴露后30天的恢复期显示出il8和il1β的恢复g中的基因表达达到基线表达水平。但是，恢复期增加了两种组织类型中差异表达基因的数量，并显着影响了经典途径。与胆固醇生物合成有关的途径在暴露期的比目鱼中有明显的恢复期，而没有暴露期的比目鱼中没有恢复期而没有得到明显抑制。暴露结束时，the中有17条途径受到显着影响，其中甲状腺激素代谢相关途径受到的影响最大。在任何组织或任何时间点，从回收鱼中得到的肝组织都具有最多的富集途径（187）。恢复期后肝脏中的细胞和体液免疫反应途径受到了很大影响，这表明免疫系统正试图对由于长期接触油脂引起的潜在损害做出反应。我们的研究结果表明，南部比目鱼的肝脏和腮组织被不同程度的改变。深水地平线油污沉积物暴露，暴露后30天的恢复期大大改变了基因表达和规范途径分布。