IDENTIFICATION OF DEVELOPMENTAL MODULES IN CEPHALOBID NEMATODES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 头状线虫科(线虫目：杆状线虫)是一种非寄生的微生物食性线虫，带有被称为喙的头皮附属物。它们几乎无处不在地分布在陆地生态系统中，但人们对它们的生物学知之甚少。前科是该群中用于分类目的的最重要的特征，它们的多样性和复杂性使它们成为进化问题的有趣模型。它们是细胞外基质的复杂延伸，这进一步增加了了解它们的形态和形态发生的重要性。2001年在NCMIR上所做的部分初步工作表明，电子断层扫描将被证明对于描述它们复杂的3D结构是非常有价值的，包括多达七种不同蛋白质层之间的关系，这些蛋白质层由鼻孔组成。这里提出的工作将有助于一个更大的项目，该项目旨在制定和测试发展模块的假说，这些假说可以用来回答关于新奇人物的起源和发展演变的一般问题。它将与系统发育、发育和扫描电子显微镜信息相结合，以解决理论上的进化问题，并提供急需的解剖学描述，以解决与系统发育分析和诊断目的中使用的特征同源性有关的问题。除了帮助实现这些研究目标外，断层重建还将包含发育遗传学家和使用线虫模型的进化生物学家感兴趣的其他感觉和摄食结构的信息，这项工作将有助于评估这项技术在理解线虫解剖学方面的更广泛应用。加州大学河滨分校的CM300中压显微镜已经可以使用，它将被用来预览材料和将截面预先曝光在电子束下。初步工作表明，对比度是获取角质层结构图像的限制因素，因此NCMIR的新能量过滤显微镜将用于获取最终的断层扫描序列。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Members of the family Cephalobidae (Nematoda: Rhabditida) are non-parasitic microbial-feeding nematodes with cephalic cuticular appendages called probolae. They are nearly ubiquitously distributed in terrestrial ecosystems, yet very little is known of their biology. Probolae are the most important characters used for taxonomic purposes in the group, and their diversity and complexity makes them interesting models for evolutionary questions. They are complex extensions of the extracellular matrix, which adds further importance to understanding their morphology and morphogenesis. Preliminary work done in part at the NCMIR in 2001 suggests that electron tomography would prove invaluable for describing their complex 3D structure, including the relationship between up to seven different protein laminates of which probolae are composed. The work proposed here would contribute to a larger project which aims to formulate and test hypotheses of developmental modules that could be utilized to answer general questions about the origin of novel characters and the evolution of development. It will be combined with phylogenetic, developmental and SEM information in order to address theoretical evolutionary questions and provide a much needed description of anatomy in order to address issues concerning the homology of characters used in phylogenetic analyses and for diagnostic purposes. In addition to helping accomplish these research goals, the tomographic reconstruction will contain information on other sensory and feeding structures of significant interest to developmental geneticists and evolutionary biologists who use nematode models, and the work will serve to evaluate the technique for much broader application in understanding nematode anatomy. Access to a CM300 mid voltage microscope at the University of California, Riverside is already available, which would be used to preview material and to pre-expose sections to the electron beam. Preliminary work showed that contrast was the limiting factor for obtaining images of cuticular structures, so the new energy filtered microscope at the NCMIR would be used for acquiring the final tomographic series.