Embryonic and larval development of the olfactory system in malacostracan crustaceans: a comparative approach

与昆虫相反，甲壳动物的中枢和外周嗅觉通路的发育还不是很清楚，尽管以小龙虾和刺龙虾为代表的软体甲壳动物的成体嗅觉系统的功能形态已经被广泛分析。由于全变态昆虫和甲壳类动物在发育周期上表现出明显的差异，本项目提出的问题是，在嗅觉系统的个体发育方面，这两个类群之间是否也存在这种差异。为了解决这个问题，我们将分析三种软体动物代表的胚胎和幼虫，它们是小龙虾Procambarus virgialis，欧洲滨蟹Carcinus maenas和双足类Parhyale Hawasis。我们之所以选择这三个分类群，是因为从实验室培养中可以很容易地接触到发育阶段，因为它们在发育周期中表现出差异，而且它们在嗅觉系统的复杂程度上也表现出差异。利用我们以前用来分析成体甲壳类嗅觉系统的一组标记，我们将分析触角的嗅觉神经元以及支配大脑初级化学感觉中心嗅叶的嗅觉间神经元(局部嗅觉中间神经元和嗅觉投射神经元)的出现和成熟的动力学。具体地说，我们感兴趣的是控制嗅叶中肾小球(致密突触神经纤维区)形成的过程，以及胶质细胞和血管在这一过程中可能扮演的角色。我们的研究不仅将为节肢动物神经发生过程的进化提供新的见解，还将为甲壳类嗅觉系统的功能形态提供新的见解。

Contrary to the insects, the development of the crustacean central and peripheral olfactory pathway is not well understood although the functional morphology of the ADULT olfactory system has been extensively analysed in representaives of the malacostracan crustaceans such as crayfish and spiny lobster. Because holometabolous insects and crustaceans display distinct differences in their developmental cycles, the current project asks the question if such differences between the two taxa may also exist concerning the ontogeny of the olfactory system. To adress this question we will analyse embryos and larvae of three malacostaracn representatives, the crayfish Procambarus virginalis, the European shore crab Carcinus maenas, and the amphipod Parhyale hawaiensis. We have choosen these three taxa because developmental stages are easily accessible from lab cultures, because they display differences in their developmental cycles, and because they display differences in the level of complexitiy of thier olfactory systems. Using a set of markers which we previously employed to analyse the ADULT crustacean olfactory system we will analyse the dynamics of emergence and maturation of the olfactory sensory neurons of the antennae and also of olfactory interneurons (local olfactory interneurons and olfactory projection neurons) innervation the primary chemosensory centers in the brain, the olfactory lobes. Specifically, we are interested in the processes that govern formation of the glomeruli (areas of dense synaptic neuropil) in the olfactory lobes and possible roles of glial cells and blood vessels in this process. Our study will not only provide new insights into the evolution of neurogenetic processes in arthropods but also into the functional morphology of the olfactory system in crustaceans.