Chun Y H, Johnson E M, Gabel B E, Cadogan A S
Teratology. 1983 Feb;27(1):81-7. doi: 10.1002/tera.1420270112.
Adult Hydra attenuata with vitally stained gastrodermal cells were dissociated into their component cells which were then randomly reaggregated into pellets by low-speed centrifugation. Representative examples of these preparations, which develop into normal adult hydra if left undisturbed, were examined fresh at low magnification and at higher magnification in fixed, stained, and sectioned specimens. The actual pellet stage lasts less than 1 hour because the adult ectodermal and gastrodermal cells rapidly sort themselves into an inner and outer layer and seem to secrete a new mesoglea immediately thereafter. The "embryo" becomes trilaminar and attains a central cavity by extruding a large amount of cellular debris at the end of the first day. At about this same time, new tentacles begin to differentiate from rapidly dividing and undifferentiated interstitial cells. Regulation of tentacle number and position occurs at the end of two days, and the body form is essentially reestablished within 60 hours by further differentiation of the hypostomes and body wall. Complete separation of the preparation into individual polyps does not occur until about 190 hours of development.
将带有经活体染色的胃皮细胞的成年细螅解离成单个细胞，然后通过低速离心将这些细胞随机重新聚集成小团块。这些制备物的典型样本如果不受到干扰会发育成正常的成年细螅，在低倍镜下新鲜观察，并在固定、染色和切片的标本中进行高倍镜观察。实际的小团块阶段持续不到1小时，因为成年外胚层和胃皮细胞会迅速自行排列成内层和外层，之后似乎会立即分泌出新的中胶层。“胚胎”在第一天结束时通过排出大量细胞碎片而变成三层并形成一个中央腔。大约在同一时间，新的触手开始从快速分裂且未分化的间质细胞中分化出来。触手数量和位置的调节在两天结束时发生，口和体壁的进一步分化在60小时内基本重新建立了身体形态。直到发育约190小时，制备物才完全分离成单个息肉。
