Developmental Neurobiology of Diffused Nervous System in Hydra

用间接免疫荧光法观察了水螅头再生和出芽过程中神经网的形成。神经网络用抗血清观察神经肽RFamide。神经网络的形成分两步：第一步是再生尖端神经节细胞的出现，第二步是顶端感觉细胞的出现，同时神经节细胞从顶端消失。根据单克隆抗体TS19的定义，上皮细胞在头部再生过程中的行为与神经网络的形成相一致。我们研究了三种形态发生突变体的神经网络形成：头部再生缺陷突变体reg-16，出芽缺陷突变体L4和多头突变体mh-1。此外，我们还研究了由野生型上皮细胞和突变型神经细胞组成的嵌合菌株，反之亦然。我们获得了明确的证据表明，神经网络的形成是由上皮细胞提供的环境控制的。

Nerve net formation was examined during head-regeneration and budding of hydra using indirect immunofluorescence on whole mounts. The nerve net was visualized with an antiserum to a neuropeptide, RFamide. The nerve net forms in two steps : the first is the appearance of ganglion cells at the regenerating tip, and the second is the appearance of sensory cells at the apex and the simultaneous disappearance of ganglion cells from the apex. The behavior of epithelial cells during head- regeneration, as defined by a monoclonal antibody TS19, corresponded with nerve net formation.We examined nerve net formation in three morphogenetic mutants : a head-regeneration deficient mutant, reg-16, a budding deficient mutant, L4, and a multi-headed mutant, mh-1. In addition, we also examined chimeric strains which consist of the epithelial cells from the wild type and nerve cells from a mutant, and vice versa.We obtained clear evidence that nerve net formation is controlled by the environment provided by the epithelial cells.