Stock identification of cultured fish and shellfish by composition of trace elements in the hard tissues : a new technology for identification of product origin.

对于鱼耳石的痕量元素指纹图谱研究，工业耦合等离子体质谱（ICPMS）在日本尚未使用。本研究是在日本养殖鱼类和贝类的硬组织中开展基于icpms的微量元素指纹图谱研究。实验结果如下：我们开发了一种标准的方法来测定鱼类耳石和贝类贝壳的微量元素组成，使用溶液基和激光研磨ICPMS。微量元素组成是鉴定培养种产品来源的有效指纹图谱。利用EPMA法测定的耳石Sr含量和Sr/Ca比值，阐明了部分鲑科和鳗鲡的洄游模式，表明EPMA法是研究溯河、溯河或双溯河鱼类洄游模式的有力工具。我们开发了一种DNA微阵列来识别大马哈鱼。该阵列具有精度高、时效性好、不需要DNA测序仪等特殊设备的特点。因此，该方法是在野外研究和船上识别大马哈鱼种群的有力工具。我们用免疫组织化学方法定位了耳石基质蛋白OMP-1和otolin-1，并指出了这些蛋白在耳石钙化和微观结构形成中的重要作用。我们还发现，通过昼夜循环，内淋巴文石饱和比维持在1.0以上，表明文石晶体生长可以持续一天。另一方面，otolin-1 mRNA表达具有明显的日节律性，夜间表达量显著增高，提示otolin-1在构建日环中具有关键功能。马苏鲑鱼血清中Sr浓度和Sr/Ca比值在海水转移后第7天出现升高。在重建溯河鱼类的洄游模式时，必须考虑到这种时间滞后。

For trace-elemental fingerprint studies in fish otoliths, industry-coupled plasma mass spectrography (ICPMS) has not used in Japan. The present study was undertaken to develop ICPMS-based trace-elemental fingerprint studies in the hard tissues of cultured fish and shellfish in Japan. Following results were obtained.1. We developed standard methods to determine trace-elemental composition of fish otoliths and shells of shellfish using solution-based and laser abration ICPMS. Trace-elemental compositions were useful fingerprints that could identify product origin of cultured species.2. We clarified migratory patterns of some salmonid and eel species using Sr contents and Sr/Ca ratio of otoliths determined by EPMA and revealed that the method is a powerful tool to study migration patterns of anadromous, catadromous or diadromous fishes.3. We developed a DNA microarray to identify stocks of chum salmon. The array was accurate and time effective, and required no special equipments such as DNA sequencer. Therefore, the method is especially a powerful tool to identify chum salmon stocks in the field study and on board.4. We immunohistochemically localized otolith matrix proteins, OMP-1 and otolin-1, and suggested important rolls of these proteins in calcification and formation of otolith micro structures. We also revealed that the aragonite saturation ratio of endolymph was maintained over 1.0 through the day-night cycle, suggesting aragonite crystal growth could be continued through a day. On the other hand, mRNA expression of otolin-1 showed clear daily rhythm with significantly higher expressions during night-time, suggesting a key fuction of otolin-1 to construct daily rings. In masu salmon, increases in Sr concentrations and Sr/Ca ratios in the serum occurred 7 days after the seawater transfer. Such a time-lag must be taken into account to reconstruct migration patterns in the anadromous fishes.