The Dynamic Architecture of a Developing Organism

Before programs: The physical origination of multicellular forms

“…However, the complex basement membranes (Lindblom and Paulsson, 1996) of epithelia confer stiffness to these tissues (Danielsen, 2004), which facilitate the storage of mechanical energy (Tidball, 1986). In combination with the biochemically excitable cellular component and the mechanical continuity fostered by cell surface-cytoplasmic linkage (Ingber et al, 1994), embryonic epithelia become capable of exhibiting tension-dependent collective cell movement (Beloussov et al, 2000) leading to complex folding, branching and bucking behaviors (Beloussov, 1998).…”

“…And in cases where these incipient cell types exhibited different amounts of adhesive molecules, adhesion-based sorting-out into distinct tissue layers and tandemly arranged segments would have been inevitable. Polarization in the expression of adhesive proteins would lead, as a physical side-effect, to aggregates with lumens; similarly, production of a stiff extracellular layer by an epithelium would cause it to act as a viscoelastic sheet with the morphological properties associated with such materials (Mittenthal and Mazo, 1983;Beloussov, 1998;reviewed in Newman, 1998). These features, The central box denotes the effects of differential adhesion in causing the formation of boundaries within a tissue mass, across which cells will not mix.…”

Morphomechanics: goals, basic experiments and models

“…were found to be mechanically stressed (Beloussov et al, 1975;Jacobson & Gordon, 1976;1980;Kiehart et al, 2000; see also Kraus, 2006;Cherdantzev, 2006;Cherdantzeva & Cherdantzev, 2006). This conclusion was made mostly by tracing the immediate deformations of tissues after localized dissections, as well as by other physical and geometrical methods (review : Beloussov, 1998). In lower invertebrates the main source of stresses is the osmotically driven periodic turgor pressure in cell vacuoles (Beloussov et al, 1993), while at the blastula stage of Echinodermata and vertebrate embryos there is a constant pressure within a blastocoel.…”

Self-Organization, Symmetry and Morphomechanics in Development of Organisms

“…After the dissection of an embryo part upper from a dotted line shown in A and closure of the wound (B) the positions of the elements P and Q (as well as all the others) will become geometrically non-homologous to the same elements' positions in A. As a result, any points of an embryo which occupy in A and B homologous positions (say, a and a1, b and b1, c and c1) will perceive quite different PI signals which is incompatible with embryonic regulations (from Beloussov, 1998).…”

“…Now we'll give a very brief and elementary review of SOT principles (for much more complete, but still popular SOT account see Capra, 1996; for a developmentally related account see Beloussov, 1998). Let the readers only slightly familiar with math be not afraid: the math will be minimal.…”