Active Principle of the Amphibian Organisation Centre

Waddington, C. H.; Needham, Joseph; Nowinski, Wiktor W.; Needham, Dorothy M.; Lemberg, R.

doi:10.1038/134103a0

Cited by 22 publications

(6 citation statements)

References 2 publications

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“…retrospective 'individuators', which act non-cell-autonomously [25]. The evocators would exist in a masked form throughout the embryo but are locally liberated or activated at organizers [26].…”

Section: Form-giving Substances or Morphogensmentioning

confidence: 99%

Patterning principles of morphogen gradients

Simsek

Özbudak

2022

Open Biol.

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Metazoan embryos develop from a single cell into three-dimensional structured organisms while groups of genetically identical cells attain specialized identities. Cells of the developing embryo both create and accurately interpret morphogen gradients to determine their positions and make specific decisions in response. Here, we first cover intellectual roots of morphogen and positional information concepts. Focusing on animal embryos, we then provide a review of current understanding on how morphogen gradients are established and how their spans are controlled. Lastly, we cover how gradients evolve in time and space during development, and how they encode information to control patterning. In sum, we provide a list of patterning principles for morphogen gradients and review recent advances in quantitative methodologies elucidating information provided by morphogens.

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Section: Form-giving Substances or Morphogensmentioning

confidence: 99%

Patterning principles of morphogen gradients

Simsek

Özbudak

2022

Open Biol.

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“…Both Eckblom et al and Tiedemann & Born implicated cell receptors as likely integral factors in an induction system. It has long been known (Waddington, 1938) that ectoderm cells can respond to several inducers and that the inducing cells initiate a response inherent in the ectoderm layer. In the present study the fibrillar fan-shaped extracellular materials are epithelial in origin .…”

Section: Primary Neural Inductionmentioning

confidence: 99%

Applications of the SEM to the analysis of morphogenetic events

England

1981

Journal of Microscopy

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SUMMARY Scanning electron microscopy (SEM) is a valuable tool for the analysis of morphogenetic events. The role of extracellular materials in primary neural induction in the early stage 5 chick embryo may be analysed by SEM as well as by histochemical techniques. During primary neural induction, extracellular materials in the early stage 5 chick embryo form a fan‐shaped region on the ectoderm anterior to Hensen's node. Fibronectin and sulphated glycosaminoglycans are present anterior to Hensen's node on the ventral ectoderm layer. It is proposed that the fanshape of extracellular materials has a dual function; as a chemical substrate to form close contacts between the inducing cells and the target ectoderm cells, and to serve as a contact guidance system for the pre‐notochordal cells.

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“…Fischer and Wehmeier [291 found that if they prepared crude glycogen by the classical method of potash digestion from mammalian liver, they could obtain inductions on implanting it underneath competent ectoderm. Similarly, Barth [ [24]), while after saponification and destruction of the kephalin, the activity of that preparation still persists (Waddington, Needham, Nowin'ski, Lemberg, and Cohen [31]). But these facts do not affect the interest of the findings of Fischer and Wehmeier on glycogen -as will be seen, they provide what may be an important clue regarding the nature of the inactive masking complex from which the evocator is normally set free in the dorsal lip of the blastopore.…”

Section: Fig83mentioning

confidence: 99%

New Advances in the Chemistry and Biology of Organized Growth

Needham

1936

Proceedings of the Royal Society of Medicine

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This paper comprises the Oliver-Sharpey Lectures for 1936, delivered at the Royal College of Physicians, together with an address to the Section of Pathology of the Royal Society of Medicine, -delivered on the above date.OCT,-PATH. 1Proceedings of the Royal Society of Medicine 3£ an implanted organizer, that is to say, whether, invaginated early, it will come to lie under the presumptive head; or, invaginated late, it will come to lie under the presumptive tail. Spemann [51, specifically investigating this subject, found that head organizer would produce heads either in head or tail regions, while tail orgauizer would produce head in head region and tail in tail region. The organizer itself contains, therefore, some hidden regional quality, determining the regional character of what will be induced, as well as some morphogenetic stimulus which will simply account for the existence of what will be induced. The former type of determination has been called Individuation, and the second type Evocation (Needham, Waddington and Needham [7]) and these terms have become generally adopted. Thus we may say that in an ordinary induction, one of these determinations, evocation, is always performed by the graft, while the other, individuation, fig.81.

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Active Principle of the Amphibian Organisation Centre

Cited by 22 publications

References 2 publications

Patterning principles of morphogen gradients

Patterning principles of morphogen gradients

Applications of the SEM to the analysis of morphogenetic events

New Advances in the Chemistry and Biology of Organized Growth

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