Spangenberg D B
Department of Pathology, Eastern Virginia Medical School, Norfolk 23501, USA.
Scan Electron Microsc. 1986(Pt 4):1609-16; discussion 1616-8.
Statolith formation in Cnidaria was reviewed with an emphasis on Aurelia statoliths. The review provides information on the chemical composition, mechanisms of initiation of mineralization, and effects of environmental factors on Cnidarian statolith formation. Environmental factors discussed included modified sea water ingredients, X-irradiation, clinostat rotation, and petroleum oil ingredients. A detailed account of the effects of cadmium on mineralization and demineralization of Aurelia statoliths is given. Cadmium at dosages of 2 to 4 micromoles significantly reduces statolith numbers in developing ephyrae. At a dosage of 3 micromoles, cadmium accelerates statolith loss in unfed ephyrae studied at 4 and 8 days following ephyrae release from strobilae. Cadmium, therefore, is shown to reduce statolith numbers in developing ephyrae and to cause greater reduction of statolith numbers in unfed ephyrae after 4 and 8 days than occurred in controls. Supplementation of Cd(2+)-containing artificial sea water (ASW) with calcium (3X and 5X ASW calcium content) results in higher numbers of statoliths at day 4 as compared with cadmium-treated ephyrae. At 8 days only the 5X calcium supplemented ASW is effective in enhancing statolith numbers in Cd(2+)-treated ephyrae. These results suggest that cadmium competes in some manner with calcium at the mineralizing sites of Aurelia.
本文综述了刺胞动物的平衡石形成，重点关注海月水母的平衡石。该综述提供了有关其化学成分、矿化起始机制以及环境因素对刺胞动物平衡石形成影响的信息。所讨论的环境因素包括改良海水成分、X射线照射、回转器旋转和石油成分。文中详细阐述了镉对海月水母平衡石矿化和脱矿的影响。剂量为2至4微摩尔的镉会显著减少发育中的碟状体的平衡石数量。在剂量为3微摩尔时，镉会加速从螅状体释放后4天和8天研究的未喂食碟状体的平衡石损失。因此，研究表明镉会减少发育中碟状体的平衡石数量，并且在4天和8天后，未喂食碟状体的平衡石数量减少幅度比对照组更大。与镉处理的碟状体相比，在含镉（2+）的人工海水中添加钙（人工海水钙含量的3倍和5倍）会使第4天的平衡石数量更多。在第8天，只有添加了5倍钙的人工海水能有效增加镉（2+）处理的碟状体的平衡石数量。这些结果表明，镉在某种程度上与钙在海月水母的矿化位点存在竞争。
