Calcification by Hermatypic Corals: Regulation of the Calcium Pathway

小行星9415936 造礁珊瑚有两种钙化模式，一种在光照下发生，一种在黑暗中发生。 碳酸钙沉积在光照下更大，这是一种归因于藻类内共生体（虫黄藻）的光合活性的现象。 有证据表明，这两种模式可能在机制和数量上有所不同。 尽管有许多研究，珊瑚钙化和虫黄藻光合作用之间的联系仍然没有得到解决。 这种联系的重要性可以简单地说：珊瑚和它们的虫黄藻的伙伴关系基本上是世界上活的（和大多数化石）珊瑚礁存在的原因。 一个主要的问题是碳酸钙基质，钙和溶解的无机二氧化碳，是否限制钙化，如果是，在什么条件下。 钙对生命系统的重要性导致了各种保存良好的钙调节机制，然而，很少有珊瑚研究已经检查了这种调节。 这一策略有大量的信息基础，从研究其他生物矿化生物和许多领域的细胞生理学。 这种方法，加上珊瑚养殖的最新进展，有望在过去十年中几乎没有取得进展的研究领域取得实质性进展。 该研究项目将侧重于珊瑚钙化是否受到骨骼生成部位（而不是海水）钙可用性的限制，以及共生体光合作用活动如何影响可用性。 使用药理学和动力学方法的组合，从海水到骨骼的钙途径将进行区室表征。 通过膜转运系统和信使系统（即cAMP、钙调蛋白）在隔室之间的钙运动和调节将是主要的兴趣。 虽然这个基础研究问题可能是这个项目的充分理由，但也有更实用价值的好处。 优化珊瑚养殖可能对珊瑚礁保护产生深远影响。 直接地，它提供了一种繁殖珊瑚以修复受损珊瑚礁的方法。 在水族馆贸易中使用珊瑚养殖可以通过减少迅速增加的野生捕捞来间接帮助天然珊瑚礁。 了解珊瑚钙化的光增强将允许操纵培养条件，以产生具有一致物理特性的骨骼。 这种骨骼将具有用于骨重建的价值，其中天然珊瑚已被成功地利用。 ***

9415936 Mueller Reef-building corals display two modes of calcification, that which occurs in the light and that taking place in the dark. Calcium carbonate deposition is greater in the light, a phenomenon attributed to the photosynthetic activity of algal endosymbionts (zooxanthellae). There is evidence that the two modes may differ in mechanism as well as quantitatively. In spite of numerous studies, the link between coral calcification and zooxanthellae photosynthesis remains unresolved. The significance of this link can be succinctly stated: the partnership of corals and their zooxanthellae is essentially responsible for the existence of the world's living (and most fossil) coral reefs. A major question is whether either of the calcium carbonate substrates, calcium and dissolved inorganic carbon dioxide, are limiting to calcification and, if so, under what conditions. The importance of calcium to living systems has led to a variety of well-conserved calcium regulatory mechanisms, however, very little coral research has examined such regulation. This strategy has a large base of information from research on other biomineralizing organisms and in many areas of cellular physiology. Such an approach, coupled with recent advances in coral culture, promises substantial progress in a research area that has made little during the past decade. This research project will focus on whether coral calcification is limited by calcium availability at the site of skeletogenesis (not in seawater) and how availability may be affected by symbiont photosynthetic activity. Using a combination of pharmacologic and kinetic approaches, the calcium pathway from seawater to skeleton will be compartmentally characterized. Calcium movement and regulation between compartments by membrane transport systems and messenger systems (i.e. cAMP, calmodulin ) will be of central interest. While this basic research question may be sufficient justification for this projec t, there are benefits of more practical value as well. Optimization of coral culture could have far reaching implications for coral reef conservation. Directly, it offers a means for propagation of corals to repair damaged reefs. Use of coral culture in the aquarium trade could indirectly help natural reefs by reducing the rapidly increasing wild harvest. Understanding the light-enhancement of coral calcification would allow manipulation of culture conditions to produce skeletons with consistent physical properties. Such skeletons would be of value for use in bone reconstruction where natural coral has been successfully employed. ***