Scutoid

The scutoid model of curved epithelia with "apico-basal cell intercalation" (c, d) compared to models of planar and invaginated epithelia made of prismatic or truncated pyramidal cells (a, b)

A Scutoid is in the broadest sense prism -like geometric shapes . This is characterized by (also concave ) curved surfaces and by at least one corner point that is not a corner point of one of the two base surfaces.

background

The Scutoid was first named and described in 2018 by a collective of Spanish biologists and mathematicians . The background was the exploration of three-dimensional reorganization simple cell layers, so-called single-high prismatic or isoprismatischer epithelia during training curved organ surfaces in the course of individual development of multicellular animals.

Illustration of the official origin of the name of Scutoid

a) Confocal microscopic images of the salivary gland of a Drosophila larva and b) Confocal microscopic detailed images and corresponding 3D reconstruction of scutoid-shaped cells of the epithelium of this salivary gland

The theoretical part of this research was carried out with the help of a mathematical modeling of curved ( hollow cylinder- shaped , ellipsoidal ) single-layer, highly prismatic or isoprismatic epithelia. In particular, the observation made by other researchers was taken into account that two cells that are directly adjacent to one another on one surface (apical surface) of a corresponding epithelium do not do so on the other surface (basal surface) of the epithelium, with their directly adjacent cells that separate them from one another on the basal surface behave in exactly the opposite way, i.e. are not immediate neighbors on the apical surface. This phenomenon is called "apico-basal cell intercalation" (German literally 'apico-basal cell intercalation') and cannot be explained with simple prismatic or truncated pyramidal cell shapes. As a sufficient solution to this geometric problem, the mathematical model calculated the scutoid for the shape of the densely packed epithelial cells.

Investigations of the salivary glands of the third larval stage of Drosophila melanogaster and the epithelium of the gastrula (50% epibolic stage) of zebrafish with the aid of a confocal microscope confirmed the existence of scutoid-shaped cells predicted by the model.

The name "Scutoid" was officially chosen because of the similarity of the 2D projection of a simple, symmetrical variant of this geometric body with the arrangement of (pro) scutum , scutellum and elytra in the dorsal armor of certain insects, especially beetles from the subfamily of rose beetles (Cetoniinae). Unofficially and originally, however, it is derived from the first surname of the head of the lead biologist working group at the University of Seville , Luis Maria Escudero Cuadrado.

Web links

Commons : Scutoide  - collection of images, videos and audio files

• The scutoid: a geometric building block of life - article by Lara Anisman on the blog of the mathematics magazine Chalkdust from March 28, 2019 (English)

Individual evidence

1. ↑ ^{a b c d} Pedro Gómez-Gálvez, Pablo Vicente-Munuera, Antonio Tagua and 13 other authors: Scutoids are a geometrical solution to three-dimensional packing of epithelia . In: Nature Communications . tape 9 , July 27, 2018, 2960, doi : 10.1038 / s41467-018-05376-1 .
2. ^ Mathematician (Universidad de Sevilla) and co-author of the Nature Communications article Clara Grima in: The Scutoid: did scientists discover a new shape? standupmaths (YouTube channel), August 3, 2018, timecode 13: 35.5