Effect of temperature on morphogenetic oscillations in Dictyostelium discoideum

Abstract

When their food supply is exhausted, single amoebae of the cellular slime mould Dictyostelium discoideum aggregate. On a two-dimensional substrate such as agar, this aggregation is the result of a succession of periodic coordinated movement steps directed towards a group of amoebae-the "centre", which may in fact lie anywhere in the field of cells. Recent theoretical and experimental work suggests that this process can be explained as follows. (1) The centre produces and releases cyclic AMP (the signal) in an oscillatory manner, and (2) other cells in the field respond chemotactically by moving up cyclic AMP gradients and relay the signal progressively outwards. By means of time-lapse cinematography we have looked at the oscillation frequency v during the aggregation of small drops (about 1,000 cells in a drop of diameter 1 mm) of D. discoideum cells (strain NC-4H) aggregating on hydrophobia agar at various temperatures, and have found that the oscillation frequency increases with temperature (Fig. 1).