Ultrastructural and immunohistochemical studies of the ontogeny of the nervous system and the mesoderm in Enteropneusta and Pterobranchia in order to elucidate deuterostome evolution.

对肠肺和翼鳃亚纲神经系统和中胚层的个体发育进行超微结构和免疫组织化学研究，以引发后口动物的进化。

• 批准号: 50294992
• 负责人: Dr. Thomas Stach
• 金额: --
• 依托单位: Forschungsgruppe Elektronenmikroskopie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/50294992?language=en
• 关键词: Ultrastructural; immunohistochemical; studies; ontogeny; nervous

Morphological and molecular data support different phylogenetic hypotheses of deuterostome taxa and therefore infer contrasting evolutionary character evolution. Many of the supposedly morphological “key characters” have not been adequately studied in proper ontogenetic or structural detail. In the present project, we analyze the ontogeny of morphological characters that have been considered important for deuterostome evolution utilizing computer assisted 3D-reconstruction based on serial transmission electron micrographs in combination with confocal laser scanning microscopy of immunolabeled specimens. We have so far documented the neurulation of the collar cord in an enteropneust and revealed that the collar cord is much more complex than was hitherto believed. E.g., areas of neuronal somata and neuropil are clearly organized in concise patterns, a intimate relation between the asymmetric proboscis pore and the collar cord exists, and we discovered a distinct gland in the mid-dorsal line that develops from a glandular ring around the entire collar. Our database allows the reconstruction of peripheral nerves in the branchial region along with coelomic cavities, blood vessels, skeletal elements, and musculature. Using serially sectioned specimens fixed for electron microscopy, we could for the first time observe the ontogenetic primordium of the pericard, corresponding to the right protocoel of other deuterostomes. Based on our detailed anatomical studies, we could find no further support for the often-quoted primary homology hypothesis between the post-anal tail of enteropneusts and the chordate tail. In the successfully collected two species of pterobranchs, we just started our morphological analyses and found similarities in the dorsal ganglion to the organization of chordate central nervous systems based on confocal laser scanning microscopical investigation of the serotonergic nervous system. Transmission electron microscopy of developmental stages of pterobranchs that were also successfully sampled, are scheduled for analysis later this year, as are studies of adult structures. In summary, this project has already yielded important results, has successfully completed acquisition of biological samples, and has therefore the potential to fulfill all goals aimed for in the original project, especially after Sabrina Kaul a PhD candidate ideally trained for this project joined the project.

形态学和分子数据支持氘代表分类群的不同系统发育假设，因此推断出对比鲜明的进化特征进化。许多预期的形态学“关键特征”尚未在适当的个体遗传学或结构细节上充分研究。在本项目中，我们分析了形态学特征的个体发育，这些特征被认为对基于串行透射电子显微照片的计算机辅助3D重建而被认为对氘代表的进化很重要，并结合了共聚焦激光扫描免疫标本标本的显微镜。到目前为止，我们已经记录了肠内神经元的绳索，并透露，衣领绳远比隐藏的要复杂得多。例如，神经元somata和Neuropil的区域清楚地以简洁的模式组织，不对称的长鼻毛孔与衣领之间存在亲密关系，我们在中间线中发现了一个独特的腺体，该腺是从整个颈环周围从腺环中发展出来的。我们的数据库允许在分支区域重建外周神经，以及腔腔，血管，骨骼元素和肌肉组织。使用固定的电子显微镜标本，我们可以首次观察到围角的个体遗传学原始，这对应于其他氘核静态的正确方案。基于我们的详细解剖学研究，我们无法进一步支持肠内尾巴和脊柱尾巴之间经常引用的主要同源性假设。在成功收集的两种翼龙中，我们刚刚开始了形态学分析，并发现了基于共焦激光扫描Seratonenergic神经系统的显微镜研究的脊全中枢神经系统的相似之处。也计划在今年晚些时候进行分析的翼龙的发育阶段的传播电子显微镜以及成人结构的研究。总而言之，该项目已经产生了重要的结果，已成功完成了对生物样品的收购，因此有可能实现原始项目中针对的所有目标，尤其是在Sabrina Kaul的博士学位候选人的理想培训为该项目加入该项目之后。