Interaction of induced and uninduced cells during primary induction

Sasaki, Naoi; Iyeiri, Sumiko; Kurihara, Kiyofumi

doi:10.1007/bf00848648

Cited by 3 publications

(3 citation statements)

References 9 publications

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“…The predominance of the dorsal sturcture in induction might be taken as evidence of strong induction as suggested by SASAKl et a/. (14) who combined induced cells with uninduced ones and demonstrated that the larger the population of induced cells in an explant, the more dorsal the quality of the structure evoked in it was. Thus, the population of cells which received the stimulus of mesodermal induction in P2 will likely always be larger than those in P3.…”

Section: Discussionmentioning

confidence: 86%

Transmission of Homoiogenetic Induction in Presumptive Ectoderm of Newt Embryo

Kurihara¹,

Sasaki²

1981

Dev Growth Differ

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J A P A N Using newt, Cyiiops pyrrliogaster., embryos, the production and/or transmission of a homoiogcnetic effect of the inddction within a presumptive ectoderm was investigated. The primary inductor was the swimbladder of a crucian carp, Caracius auratus. In the first experiment, a piece of presumptive ectoderm was isolated from an early gastrula and one-third of its inner surface was placed in contact with the swimbladder for 30 min. After removal of the inductor, the ectodermal piece was allowed to stand by itself for several hours (pre-cultivation), and then it was divided into three parts of equal size, i.e. the end that had been placed in contact with the swimbladder (PI), the next middle (P2) and the end part (P3).The tissues produced in each part were examined after 10 days' cultivation in Holtfreter's solution. The induction was evoked not only in PI, but also in P2 and P3 which had been free from the inductor. The incidences of tissue differentiation in P2 and P3 increased with the lapse of the pre-cultivation time, and the rise in P3 came after P2. These results suggested that the mesodermal tissues in the parts not placed in contact with the swimbladder (P2 and P3) were evoked by the homoiogenetic stimulus which came from PI and P2, respectively.In the next experiment, P2 of the ectodermal piece was substituted by an aged ectoderm which had lost its primary competence. In this system, the mesodermal induction was not evoked in P3. This suggested that the production of the homoiogenetic activity of the ectoderm might be associated with its cornpetenece.In the analysis of the primary induction system, the main line of research has been concerned with heterogenetic induction, in which the inductor (the archenteron roof) and the induced tissue (the neural plate) belong to different germ layers. However, besides the heterogenetic nature of primary induction, its homoiogenetic or assimilatory aspect can be seen in the pioneering work on primary induction by SPEMANN and MANGOLD (I). The secondary primodium consisted partly of the light tissue of the organizer (Triton cristatus) and partly of the pigmented materials of the host (T. tcreniatus). The homoiogenetic nature of this induction was clearly established by the discovery of neural induction by the neural tissue (2). Recently, an analytical approach to homoiogenetic induction was made by DEUCHAR (3). She made a combination experiment on a small number of induced cells (labelled with 3H-TdR) with a much larger number of uninduced cells (unlabelled) of Xenopus embryo, and she discovered that the participation of the uninduced cells in the formation of neural tissues in the induced cells had taken place in her system. The same was demonstrated by RASILO and LEIKOLA (4) with a quailchick system.

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Section: Discussionmentioning

confidence: 86%

Transmission of Homoiogenetic Induction in Presumptive Ectoderm of Newt Embryo

Kurihara¹,

Sasaki²

1981

Dev Growth Differ

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“…The mesenchymal cells in the combinants differed from those of the mesodermalized ectoderm itself (Fig. 1); the mesenchymal cells were frequently observed in the combinants, although they were hardly observed in the mesodermalized ectoderm itself (Sasaki et al 1976). The results indicates that the mesodermalized ectoderm becomes highly capable of inducing the formation of neural structures.…”

Section: Differentiation Of Mesodermalized Ectoderm and Its Neuralindmentioning

confidence: 95%

Neural-inducing activity of newly mesodermalized ectoderm

Suzuki

Yoshimura

Yano

1986

Roux’s Arch Dev Biol

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Summary. The neural-inducing activity of artificially mesodermalized ectoderm was examined. The competent ectoderm of early Cynops gastrula was mesodermalized by being placed in contact with Carassius swimbladder. The mesodermalized ectoderm was combined with ectoderm isolated from various developmental stages of a gastrula. Neural differentiation were observed in half the combinants, even in 18 h ectoderm, which is considered to have lost its neural competence within 6 h. This indicates that mesodermalized ectoderm is capable of inducing neural tissues at the very time it comes into contact with 18 h ectoderm. From the present study, the neural-inducing activity of mesodermalized cells may possibly be closely connected to the early process of their mesodennalization.

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“…Studies on the primary competence of the presumptive ectoderm in the primary induction system have been mainly concerned so far with its change and disappearance with the advance of the development of embryos after the gastrula stage (3,8,9,19,20,21,23,25,26,29).…”

mentioning

confidence: 99%

Staging of Newt Blastula Embryos and First Appearance of Primary Mesodermal Competence

Sasaki¹,

Iwamoto²,

Noda³

et al. 1976

Dev Growth Differ

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Using the swimbladder of the crusian carp (Carrasius auratus) as an inductor, the first appearance of mesodermal competence in the presumptive ectoderm of the newt (Triturus pyrrhogaster) blastula was investigated. The time course of embryonic development before the gastrula stage was determined by counting the number of surface cells on a 0.25 mm line at the animal pole. Pregastrula embryos with 2–3, 4–5, 6–7 and 7–8 cells roughly correspond to those at 14, 14–12, 8–6 and 4–0 hr before the beginning of gastrulation. Using presumptive ectoderm of the early gastrula stage, 15 min was found to be the minimum time of contact necessary for the realization of induction. The reactivity of the presumptive ectoderm from pregastrula embryos was tested by 30 min contact. Presumptive ectoderm up to the 4–5 cell stage did not react to the inductor. It may become competent within the next 4–8 hr, since the ectoderm from embryos in the 6–7 cell stage was reactive.

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Interaction of induced and uninduced cells during primary induction

Cited by 3 publications

References 9 publications

Transmission of Homoiogenetic Induction in Presumptive Ectoderm of Newt Embryo

Transmission of Homoiogenetic Induction in Presumptive Ectoderm of Newt Embryo

Neural-inducing activity of newly mesodermalized ectoderm

Staging of Newt Blastula Embryos and First Appearance of Primary Mesodermal Competence

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