title: Spontaneous emergence of large-scale cell cycle synchronization in amoeba colonies.
abstract: Unicellular eukaryotic amoebae Dictyostelium discoideum are generally believed to grow in their vegetative state as single cells until starvation, when their collective aspect emerges and they differentiate to form a multicellular slime mold. While major efforts continue to be aimed at their starvation-induced social aspect, our understanding of population dynamics and cell cycle in the vegetative growth phase has remained incomplete. Here we show that cell populations grown on a substrate spontaneously synchronize their cell cycles within several hours. These collective population-wide cell cycle oscillations span millimeter length scales and can be completely suppressed by washing away putative cell-secreted signals, implying signaling by means of a diffusible growth factor or mitogen. These observations give strong evidence for collective proliferation behavior in the vegetative state.
authors.affiliation: Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Segota
authors.forename: Laurent
authors.initials: L
authors.lastname: Boulet
authors.forename: David
authors.initials: D
authors.lastname: Franck
authors.forename: Carl
authors.initials: C
authors.lastname: Franck
mesh_terms: D002453:Cell Cycle; D049109:Cell Proliferation; D004023:Dictyostelium / Q000166:cytology* / Q000254:growth & development*; D008954:Models, Biological; D010507:Periodicity