Mechanically driven branching of bacterial colonies

Area of Science:

• Mathematical Biology
• Microbiology
• Pattern Formation

Background:

• Bacterial colonies often exhibit complex spatial patterns.
• Understanding the mechanisms driving these patterns is crucial for microbiology and synthetic biology.

Purpose of the Study:

• To develop and analyze a continuum mathematical model for pattern formation in bacterial colonies.
• To investigate the key factors influencing the emergence of finger-like and branched structures.

Main Methods:

• A sharp-interface continuum mathematical model was formulated.
• The model incorporates chemical field evolution (Monod-like uptake), bacterial chemotaxis, viscous interactions, and surface tension.
• Analytical stability analysis and nonlinear simulations were performed.

Main Results:

• Linear analysis shows the colony front is unstable under specific parameter choices.
• Nonlinear simulations confirm the development of finger-like patterns with wavelengths dependent on problem parameters.
• Branching patterns are favored when diffusion dominates chemotaxis or at high friction parameters.

Conclusions:

• The mathematical model successfully describes pattern selection in bacterial colonies.
• Results provide insights into the physical and chemical drivers of colony morphology.
• The findings can inform the design of engineered bacterial patterns.