ANNELID REGENERATION

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。 动物再生失去的身体部位的能力有很大的不同。例如，许多啮齿动物(如海葵)、环节动物(节虫)和扁虫(扁虫)具有惊人的再生能力，能够从原始动物的一小部分再生整个成虫。相比之下，大多数羊栖类脊椎动物(哺乳动物、鸟类、爬行动物)和蜕皮虫门(如节肢动物、线虫)的再生能力相对较差；尽管这些生物的再生能力有限，但几乎没有一种生物能再生其主体轴的一部分，也没有一种生物能从一小块碎片再生出完整的身体。动物之间再生潜能的系统发育分布强烈地表明，祖先动物具有广泛的再生能力，再生能力的丧失已经成为许多动物谱系的主要进化趋势。 要了解再生丧失的最终和直接原因，需要详细了解再生和非再生物种的进化力量和发育机制，最好是密切相关的物种。我们已经确定了一组小型淡水环节动物(节段)蠕虫，即链状寡毛虫，其中包括密切相关的物种，它们再生头部的能力明显不同。头部再生似乎是该种群的祖先，而非向前再生的物种可能代表着至少两个独立的和相对较新的再生能力进化损失。因此，NAIDINE是调查再生能力自然丧失的根本原因的一个很好的系统。 我们目前正在研究再生和非再生物种的一系列发育现象(细胞分裂、程序性细胞死亡、细胞迁移、神经系统动力学、身体模式)(美国国家科学基金会授予IOB-0520389)，以确定哪些过程正常发生，哪些过程不能在非再生物种中发生。我们现在急于扩大我们的研究范围，以包括生物电事件，如离子电流和电压梯度，这些事件越来越被认为与再生潜力密切相关。我们目前项目的主要目标是描述至少一个再生物种(我们的主要关注点是Pristina leidyi，它特别透明和易于操作)在头部截肢后最初24小时内的膜电压变化和离子电流，然后研究至少一个非再生物种的这些特征。我们的预期是，再生物种和非再生物种在截肢后的电压变化和离子通量将显示出明显不同的模式。

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. Animals vary dramatically in their ability to regenerate lost body parts. Many cnidarians (e.g., anemones), annelids (segmented worms), and platyhelminths (flatworms), for example, have fantastic regeneration abilities and are capable of regenerating an entire adult from a small portion of the original animal. In contrast, most amniote vertebrates (mammals, birds, reptiles) and ecdysozoan phyla (e.g., arthropods, nematodes) are relatively poor regenerators; though capable of some limited regeneration, almost none of these organisms can regenerate parts of their primary body axis and none can regenerate a complete body from a small fragment. The phylogenetic distribution of regeneration potential across animals strongly suggests that the ancestral animal had extensive regeneration abilities and that loss of regeneration abilities has been a major evolutionary trend in many animal lineages. Understanding the ultimate and proximate causes of regeneration loss requires a detailed understanding of the evolutionary forces and developmental mechanisms operating in regenerating and non-regenerating species, preferably closely related ones. We have identified a group of small, freshwater annelid (segmented) worms, the naidine oligochaetes, that includes closely related species differing markedly in their ability to regenerate their heads. Head regeneration appears to be ancestral for the group and non-anteriorly regenerating species are likely to represent at least two independent and relatively recent evolutionary losses of regeneration ability. Naidines are therefore an excellent system in which to investigate the underlying causes of natural losses of regeneration ability. We are currently investigating a range of developmental phenomena (cell division, programmed cell death, cell migration, nervous system dynamics, body patterning) across both regenerating and non-regenerating species (NSF grant IOB-0520389) in order to identify processes which occur normally and which fail to occur in non-regenerating species. We are now eager to expand our studies to include bioelectric events, such as ion currents and voltage gradients, which are increasingly being recognized as intimately linked to the potential to regenerate. Our main goal for the current project is to describe membrane voltage changes and ion currents during the first 24 hours following head amputation in at least one regenerating species (our primary focus would be on Pristina leidyi, which is particularly transparent and easy to manipulate) and then to investigate these features in at least one of the non-regenerating species. Our expectation is that regenerating and non-regenerating species will display markedly different patterns of post-amputation voltage changes and ion fluxes.