Induction of cAMP receptors by disaggregation of the multicellular complexes of Dictyostelium discoideum

Subcultivated rat lingual epithelial cells when grown on collagen gels at a liquid-gas interface achieve a highly ordered state that closely resembles the parent tissue. Three distinct cell layers are present; basal, spinous, and keratinized. Basal cells are cuboidal in shape and form a complex interface with the underlying collagen fibrils. Spinous cells form a layer 5–10 cells thick and, with the exception of keratohyalin granules, possess an organellar complement identical with native cells, including membrane-coating granules. The keratinized cell layer increases in thickness as a function of time spent in culture. Forty or more plies of terminally differentiated cells are observed following a 30-day culture period. Terminally differentiated cells while retaining pycnotic nuclei and some other organellar debris are principally envelope-enclosed squames filled with tonofilaments. Keratinization is a continuing process which occurs simultaneously across the full expanse of the culture surface. The high degree of tissue organization observed appears to be the result of feeding the cultures from the undersurface.