[Localization of cholinesterase-Activity during gastrulation of the sea urchin embryo].

The localization of cholinesterase (ChE)-activity during gastrulation of the sea urchin embryo was investigated at the cellular level by histochemical methods.ChE-activity was found in primary and secondary mesenchyme cells and in the invaginating archenteron.In the course of development, ChE-activity disappears from primary mesenchyme cells.

[Cholinesterase in the development of the chick limb : II. Enzyme activity and locomotory behavior of the presumptive cartilage cellsin vitro].

From our previous work we have put forward the hypothesis that cholinesterase activity in embryonic cells is related to morphogenetic movements. Therefore, the locomotory behavior of mesenchymal cells differentiating into cartilage by passing through a phase of Cholinesterase activity was analysedin vitro.Mesenchymal cores of chick limb buds stage 23/24 were partially disaggregated and cultured in plastic tissue culture dishes (Fig.

[The induction of visceral cartilage from cranial neural crest by pharyngeal endoderm in hanging drop cultures and the locomotory behaviour of the neural crest cells during cartilage differentiation].

1. Cranial neural crest cells and pharyngeal primordia ofTriturus alpestris were cultured together by the hanging drop method at 20 °C. 2.

[Cholinesterase in the development of the chick limb : I. Phases of cholinesterase activity in the early bud and in the demarkating cartilage and Muscle Anlagen].

1. In the chick limb bud, histochemical Cholinesterase (ChE) activity has been studied from stage 13 of Hamburger and Hamilton to stage 29 (6 days). 2.