Bacterial motility and clustering guided by microcontact printing

Area of Science:

• Microbiology
• Biophysics
• Cellular Biology

Background:

• Type IV pili are essential bacterial nanomotors.
• These pili mediate surface behaviors such as spreading and clustering.
• Understanding the factors influencing these behaviors is crucial for bacterial motility research.

Purpose of the Study:

• To investigate the quantitative relationship between bacterial motility and membrane fluidity.
• To analyze the transition from spreading to clustering behavior in Neisseria gonorrhoeae.
• To determine the critical thresholds for bacterial number and surface density that trigger behavioral changes.

Main Methods:

• Utilizing microcontact printing to create confined nonfluid islands within a fluid lipid membrane.
• Observing and analyzing single-cell surface motility in real time.
• Quantifying bacterial number and surface density on confined areas.

Main Results:

• Bacterial velocity is quantitatively dependent on phospholipid membrane fluidity.
• The transition from spreading to clustering is triggered by bacterial number (7.5 +/- 0.3) on small islands.
• For islands larger than 25 micrometers squared, the transition is triggered by surface density (56 +/- 2%).

Conclusions:

• Membrane fluidity is a key determinant of Type IV pili-mediated motility.
• Bacterial aggregation behavior is regulated by both cell number and surface density in confined environments.
• This study provides quantitative insights into the physical mechanisms governing bacterial surface dynamics.