DEVELOPMENT IN ONE-DIMENSION - THE RAPID DIFFERENTIATION OF DICTYOSTELIUM-DISCOIDEUM IN GLASS-CAPILLARIES

When Dictyostelium discoideum cells are drawn into a fine glass capill ary, they rapidly begin the first steps toward the formation of presta lk and prespore zones. Some of the events occur within a minute or two , whereas others follow later. The cells in the front segment are acti vely motile and those in the hind segment are passive. The volumes of the segments are proportional for different-sized cell masses, and tho se proportions are the same as those found in normal slugs. When the c ells are stained with the vital dye neutral red, the anterior zone bec omes darker simultaneously with the formation of the division line. Gr een fluorescent protein expressed from a stalk-specific promoter is sy nthesized mostly in the anterior end. Later, this capillary prestalk z one shows a sharp increase in alkaline phosphatase activity, which is known to be characteristic of prestalk cells.