The organization and differentiation of nervous cells in tissue cultures (a minireview)

Single stages of histiotypic formation from dissociated embryonic brain cells are described. The first stage, i.e. primary adhesion, is a phenomenon depending mainly on physicochemical features of the adhesive system. The composition of the membrane glycoprotein coat was studied during membrane regeneration and formation of cellular contacts. At the beginning single terminal sugar components and negative sialic acid residues are distributed non-homogeneously over the membrane according to the ligation of lectins. During the formation of cellular contacts this non-homogeneity progressively disappears, the thickness of the layer is reduced, however, the density of single markers increases. The highest increase of both density and layer thickness during the phase of membranes reparation occurs when the negative surface groups are labelled with cationized ferritin. The sorting out process was studied in mixed cultures as a stage of final specific recognition. It is assumed that the reaggregation of cells is a multistep process depending on maturation of the glycoprotein coat, characterized by multiple cellular adhesion and deadhesion, completed by specific recognition and fixation of recognized cells.