Nephrogenesis in molluscs and sipunculans - did the molluscan kidney evolve independently?

软体动物和星体动物的肾发生——软体动物的肾是独立进化的吗？

• 批准号: 72988980
• 负责人: Dr. Bernhard Ruthensteiner
• 金额: --
• 依托单位: Zoologische Staatssammlung München
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/72988980?language=en
• 关键词: Nephrogenesis; molluscs; sipunculans; did; molluscan

The homology of the molluscan kidneys to (in particular annelid) metanephridia versus a molluscan-specific organ (“emunctorium”) is still a matter of debate. Previous studies on nephrogenesis in molluscs are scarce or have been non-conclusive, whereas detailed comparative data on polychaetes are available. Own preliminary investigations on nephrogenesis on certain conchiferan molluscs revealed a functional protonephridial stage prior to formation of pericardium and heart. This contradicts earlier data on molluscan kidneys being derived from outgrowing “pericardioducts”. The proposed investigation of members of four molluscan classes (Polyplacophora, Gastropoda, Bivalvia, Scaphopoda) plus a member of the Sipuncula as outgroup, with a combined light and electron microscopic analysis followed by computer based 3Dvisualization shall provide detailed knowledge on nephrogenesis in these taxa. The expected results will provide decisive information on several unresolved issues like: (1) the appearance of a “protonephridial” stage in the basic development pattern of the molluscan adult kidney; (2) the homology relation between the two excretory systems appearing consecutively during ontogeny of molluscs, the protonephridia and kidneys; (3) homology relations of the molluscan and polychaete (and other lophotrochozoan) nephridial systems.

软体动物肾脏与后肾管（特别是环节动物）的同源性与软体动物特有的器官（“emunctorium”）的同源性仍然是一个有争议的问题。以前的研究肾发生在软体动物是稀缺的或已非决定性的，而详细的比较数据多毛类。对某些贝壳类软体动物肾发生的初步研究表明，在心包和心脏形成之前，有一个功能性的原肾阶段。这与早期关于软体动物肾脏来源于长出的“心包管”的数据相矛盾。四个软体动物类（多板纲，腹足纲，双壳纲，舟足纲）的成员加上一个成员的星虫作为外群，结合光镜和电镜分析，然后基于计算机的三维可视化的建议调查应提供详细的知识肾在这些类群。这些结果将为以下几个尚未解决的问题提供决定性的信息：（1）软体动物成体肾脏基本发育模式中“原肾”阶段的出现，（2）软体动物个体发育过程中相继出现的两个排泄系统--原肾和肾脏之间的同源关系，（3）软体动物个体发育过程中出现的两个排泄系统--原肾和肾脏之间的同源关系。（3）软体动物与多毛类动物（及其它枝轮动物）肾管系统的同源关系。