Marine Environmental Biology, University of Southern California, 3616 Trousdale Pkwy, Los Angeles, CA 90089, USA.
Mol Ecol. 2011 Jul;20(14):2942-54. doi: 10.1111/j.1365-294X.2011.05152.x. Epub 2011 Jun 15.
Mass mortality events occur in natural and cultured communities of bivalve molluscs. The Pacific oyster, Crassostrea gigas, is a dominant species in many intertidal locations as well as an important aquacultured bivalve species, and for the last 50 years, adult oysters have suffered frequent and extreme mass mortality events during summer months. To investigate the molecular changes that precede these mortality events, we employed a novel nonlethal sampling approach to collect haemolymph samples from individual oysters during the period that preceded a mortality event. Microarray-based gene expression screening of the collected haemolymph was used to identify a mortality gene expression signature that distinguished oysters that survived the mortality event from those individuals that died during the event. The signature was cross-validated by comparing two separate episodes of mortality. Here, we report that near-mortality oysters can be distinguished from longer-lived oysters by the elevated expression of genes associated with cell death, lysosomal proteolysis, and cellular assembly and organization. These results show the potential utility of nonlethal sampling approaches for investigating the environmental causes of mortality in natural populations in the field, and for predicting when such events could occur and which individuals will be affected.
大规模死亡事件发生在双壳贝类的自然和养殖群体中。太平洋牡蛎（Crassostrea gigas）是许多潮间带地区的优势物种，也是一种重要的养殖双壳贝类物种，在过去的 50 年中，成年牡蛎在夏季经常发生极端的大规模死亡事件。为了研究这些死亡事件之前发生的分子变化，我们采用了一种新颖的非致死性采样方法，在死亡事件发生前的一段时间内从单个牡蛎中采集血淋巴样本。我们利用基于微阵列的基因表达筛选技术，对采集到的血淋巴进行基因表达分析，以确定一个能区分在死亡事件中幸存下来的牡蛎和死亡个体的死亡基因表达特征。通过比较两次单独的死亡事件对该特征进行了交叉验证。在这里，我们报告说，濒临死亡的牡蛎可以通过与细胞死亡、溶酶体蛋白水解和细胞组装与组织相关的基因的高表达与寿命更长的牡蛎区分开来。这些结果表明，非致死性采样方法在调查野外自然种群中死亡的环境原因以及预测此类事件何时发生以及哪些个体将受到影响方面具有潜在的应用价值。
