盐度是水生生物赖以生存的关键环境因素,发展,分布,和生理表现。由于天气原因,河口和沿海地区经常发生盐度波动,潮汐,和淡水流入,从而严重影响沿海海洋水产养殖。北部的QuahogMercenariamercenaria是美国大西洋沿岸的重要水产养殖物种,但是关于盐度胁迫对生理影响的信息,免疫学,分子反应仍然很少。这项研究的目的是通过北部quahogs的长期低盐度和高盐度挑战来研究细胞和分子反应。目标是:1)在15(低盐度)的三个月盐度挑战下,衡量市场规模的quahogs的存活率,25(控制),和35ppt(超盐度);2)通过分析免疫功能确定血细胞的细胞变化;3)确定g中总游离氨基酸浓度的变化,和4)使用RNAseq技术和qPCR验证评估the的分子反应。经过三个月的盐度挑战,没有观察到死亡,并且在高盐度组中发现体重增加明显更高。Northernquahogs在周围海水中平衡了血淋巴渗透压,并被证实是渗透整合物。观察到总血细胞浓度存在显着差异,溶酶体存在,ROS生产,和吞噬率,但在细胞活力方面没有发现差异。the内总游离氨基酸浓度与水盐度呈正相关,表明氨基酸是关键的有机渗透物质。使用RNAseq的g转录组揭示了编码氨基酸转运蛋白(SLC6A3,SLC6A6,SLC6A13,SLC25A38)的差异表达基因(DEG),离子通道蛋白(T38B1,GluCl,ATP2C1),和水通道蛋白(AQP8)在低盐度或/和高盐度组中,表明这些基因在细胞内等渗调节中起关键作用。总的来说,这项研究的发现为北部quahogs的渗透调节提供了新的见解。
Salinity is a key environmental factor for aquatic organisms for survival, development, distribution, and physiological performance. Salinity fluctuation occurs often in estuary and coastal zones due to weather, tide, and freshwater inflow and thus heavily affects coastal marine aquaculture. The northern quahog Mercenaria mercenaria is an important aquaculture species along the Atlantic coast in the US, but information on the effects of salinity stress on physiological, immunological, and molecular responses is still scarce. The goal of this study was to investigate cellular and molecular responses through challenges of long-term hypo- and hyper-salinities in northern quahogs. The objectives were to: 1) measure the survival of market-sized quahogs under a three-month salinity challenge at 15 (hyposalinity), 25 (control), and 35 ppt (hypersalinity); 2) determine cellular changes of hemocytes through analysis of immune functions; 3) determine changes of the total free amino acid concentration in gills, and 4) evaluate the molecular responses in gills using
RNAseq technology with qPCR verification. After a three-month salinity challenge, no mortality was observed, and increases in body weight were identified with a significantly higher increase in the hypersalinity group. Northern quahogs equilibrated their hemolymph osmolality with the ambient seawater and were verified to be osmoconformers. Significant differences were observed in total hemocyte concentration, lysosomal presence, ROS production, and phagocytic rate, but no differences were found in cell viability. The total free amino acid concentration within gills was positively correlated to water salinity, indicating amino acids were critical organic osmolytes. The transcriptome of gills using
RNAseq revealed differential expression genes (DEG) encoding amino acid transporters (SLC6A3, SLC6A6, SLC6A13, SLC25A38), ion channel proteins (T38B1, GluCl, ATP2C1), and water channel protein (AQP8) in hyposalinity or/and hypersalinity groups, indicating these genes play critical roles in intracellular isosmotic regulation. Overall, the findings in this study provided new insights into osmoregulation in northern quahogs.