Pili mediated intercellular forces shape heterogeneous bacterial microcolonies prior to multicellular differentiation

Area of Science:

• Microbiology
• Biophysics
• Bacterial Physiology

Background:

• Microcolonies are early-stage bacterial aggregates, crucial for biofilm formation.
• Cellular behavior changes significantly with the transition from single-cell to communal lifestyles.
• Understanding cell differentiation within high-density bacterial communities is essential.

Purpose of the Study:

• To investigate the emergence of differential cell behavior in bacterial microcolonies.
• To determine the factors influencing motility differences within Neisseria gonorrhoeae microcolonies.
• To explore the mechanical basis of cell heterogeneity in early bacterial communities.

Main Methods:

• Live imaging of merging microcolonies and single-cell tracking.
• Observation of bacterial motility within microcolonies.
• Development and simulation of a single-cell biophysical model.

Main Results:

• Neisseria gonorrhoeae cells exhibit heterogeneous motility within an hour of microcolony formation.
• Cells near the microcolony surface show higher motility than central cells.
• Simulations suggest mechanical forces drive this differential behavior.

Conclusions:

• Mechanical forces are a key factor in generating cell behavior heterogeneity in microcolonies.
• This mechanical origin of differentiation may facilitate progression to mature biofilms.
• Early cell differentiation is a fundamental aspect of bacterial community development.