Spatial attractors in aggregation patterns of Dictyostelium discoideum

Area of Science:

• Cellular Biology
• Biophysics
• Developmental Biology

Background:

• Slime mould Dictyostelium discoideum exhibits self-organized chemotactic cell motion.
• Cellular aggregation is guided by cyclic adenosine monophosphate (cAMP) signaling.
• cAMP signals propagate as spiral or target patterns.

Purpose of the Study:

• Analyze chemotactic cell motion in Dictyostelium discoideum aggregation patterns.
• Investigate the dynamics of cell movement in response to cAMP signals.
• Characterize the spatial organization of cells around spiral and target patterns.

Main Methods:

• Computerized cross-correlation method for analyzing cell motion.
• Streamline calculation of probable cell trajectories.
• Observation of cell movement in response to propagating cAMP waves.

Main Results:

• Vortex-like cell rotation observed near spiral wave cores (max velocity 15 microns/min).
• Cell motion and spiral tip orbiting occur in opposite rotational senses.
• Identification of a spatial-limit cycle (approx. 130 microns radius) defining the spiral core boundary.
• Radial, star-shaped cell motion organized by target pattern pacemakers.

Conclusions:

• Cellular movement is self-organized by cAMP signals in Dictyostelium discoideum.
• Spiral waves induce rotational cell motion and form cell-free disks.
• Target patterns drive radial cell movement, leading to mound formation.