Eccentric motions of spiral cores in aggregates ofDictyosteliumcells

Abstract

Siegert and Weijer presented evidence indicating the existence of spiral waves of cell migration induced by cyclic adenosine monophosphate (cAMP) in hemispherical aggregates (mounds) of Dictyostelium cells [Current Biol. 5, 937 (1995)]. Here I report experimental evidence of the eccentric motion of the spiral core in single mounds of the wild-type strain NC-4. I observed two types of motion of the spiral core. One type is a core shift, in which a spiral core initially situated at the center of a circular mound moves toward the circular boundary of the mound. Another type is a continuous drift of a spiral core along the circular boundary. To obtain some insights into the mechanism of the motion of the spiral cores, I perform a numerical simulation of spiral waves in two-dimensional excitable media with a circular boundary.