Competing Patterns of Signaling Activity in Dictyostelium discoideum

TL;DR

This study investigates how chemical signaling patterns in Dictyostelium discoideum change with cell density, revealing a transition from concentric waves to spiral wave nucleation driving aggregation.

Contribution

It provides the first detailed analysis of the competition between signaling patterns and their dependence on cell density in Dictyostelium discoideum.

Findings

At low density, concentric waves dominate without spiral formation.

High density leads to spiral wave nucleation and entrainment.

Signaling pattern type influences aggregation mechanisms.

Abstract

Quantitative experiments are described on spatio-temporal patterns of coherent chemical signaling activity in populations of {\it Dictyostelium discoideum} amoebae. We observe competition between spontaneously firing centers and rotating spiral waves that depends strongly on the overall cell density. At low densities, no complete spirals appear and chemotactic aggregation is driven by periodic concentric waves, whereas at high densities the firing centers seen at early times nucleate and are apparently entrained by spiral waves whose cores ultimately serve as aggregation centers. Possible mechanisms for these observations are discussed.