The role of the fibrillar component of the surface sheath in the morphogenesis of Dictyostelium discoideum

Preparation of slime sheath from Dictyostelium discoideum

“…There has been some speculation as to the role of slime sheath in determining the rate and direction of migration of slugs [1][2][3]. In contrast to the putative structural component, which is largely cellulose and contains little protein [4], we show that the whole slime sheath is highly proteinaceous the proportions of stalk, spore and basal disc cells in the mature fruiting body [2].…”

“…1 we show photomicrographs of the slime trails of slugs of strains NP84 and AX3 (the strain used by Freeze and Loomis [4] prepared under identical conditions. 1 we show photomicrographs of the slime trails of slugs of strains NP84 and AX3 (the strain used by Freeze and Loomis [4] prepared under identical conditions.…”

“…Under suitable conditions the aggregate forms a slug which migrates for several days, leaving behind a trail of collapsed slime sheath through which the cell mass has passed. Slime sheath has not previously been isolated and characterized, although Freeze and Loomis [4] have purified a component, probably the structural component, which is insoluble in 9 M urea/2% sodium dodecyl sulphate (SDS). Also, since the surface sheath is the only structural component of the aggregate, it has been suggested that it may be involved in the determination of patterning, i.e.…”

Protein synthesis during development and differentiation in the cellular slime mould Dictyostelium discoideum

“…For example, slug migration is abnormal in Nacetylglucosaminidase mutants (Loomis, 1980), possibly because the structure of the slime sheath is abnormal (Watts & Treffry, 1975;Freeze & Loomis, 1977), and this could be a greater disadvantage in the wild than in the laboratory where slug migration need not occur (Newell et al, 1969b). On the other hand, accumulation of the glycosidase enzymes can also occur in some growth conditions and it is possible that the enzymes are important for growth rather than for development.…”

cAMP and DIF-1 Repress the Expression of the Dictyostelium MADS-Box Gene srfA at Early Stages of Development

“…Dictyostelium discoideum aggregates are surrounded by a sheath of extracellular matrix composed of proteins, cellulose and polysaccharides (15). The cells in the aggregate interact with each other by relatively weak adhesion mechanisms (16,17).…”