Natural Inducers of Larval Settlement and Metamorphosis Associated With Mangrove Leaves: Identity and The Role of Bacteria In Their Production.

海洋无脊椎动物物种的生命周期通常包括 浮游幼虫必须先在底栖底质上定居， 它们会变形成成虫 这些物种包括可食用的 贝类，如贻贝、牡蛎和鲍鱼， 如藤壶、水螅和苔藓虫等生物。 过程 并不是随机的 许多人，如果 并不是大多数被调查的物种对特定的化学物质有反应 与他们的成人环境有关。 之甚少 知道这些“自然”的线索，只有少数人已经或 部分或全部识别。 本研究将着重于确定和记录 自然化学线索的沉降和变形 “倒置”水母Cassiopea xamachana的扁平幼虫。 初步证据显示，该物种的幼虫 尤其是老的，退化的红树林叶子。 larvillage出现 对叶子释放的可溶性化学物质做出反应， 直接从叶子扩散或细菌作用的结果 在分解过程中。 细菌在产生特异性 将确定幼虫定居的线索。 的事实 另一个遗传实体（例如细菌）可以发挥重要作用， 在生命周期中的作用不同的物种在自然界中更常见 比原来想象的要多 水母幼虫是相对简单的动物， 更复杂的“高等”无脊椎动物，如贝类。 因此，细胞，分子和生理机制， 沉降和变形可能更容易解释和提供 其他无脊椎动物的“模型”。

Marine invertebrate species often have life cycles involving planktonic larvae which must settle on benthic substrates before they metamorphose into the adult form. Such species include edible shellfish likde mussels, oysters and abalone, as well as fouling organisms such as barnacles, hydroids and bryazoans. The process of settlement and metamorphosis is not random. Larvae of many, if not most of the species investigated respond to specific chemicals associated with their adult environment. Relatively little is known about these "natural" cues, and only a few have been either partially or completely identified. This study will focus on identifying and documenting the origin of the natural chemical cues of settlemlent and metamorphosis of planulae larvae of the "upside down" jellyfish Cassiopea xamachana. Preliminary evidence shows that the larvae of this species settle preferentially on old, degrading mangrove leaves. Larvae appear to respond to soluble chemicals released from the leaf, either diffusing directly from the leaf or the result of bacterial action during decomposition. The role of bacteria in producing specific cues for the settlement of larvae will be determined. The fact that another genetic entity (e.g. bacteria can play an integral role in the life cycle a different species is more common in nature than originally thought. Larvae of jellyfish are relatively simple animals, compared with more complicated "higher" invertebrates such as shellfish. Therefore the cellular, molecular and physiological mechanisms in settlement and metamorphosis may be easier to elucidate and provide a "model" for other invertebrate species.//