Force and flexibility of flailing myxobacteria

Area of Science:

• Microbiology
• Biophysics
• Bacterial Motility

Background:

• Myxococcus xanthus exhibits gliding motility via two mechanisms: S-type (Type IV pili) and A-type.
• A-type motility's force generation and mechanism remain poorly understood, with slime extrusion as a hypothesis.
• Previous experiments noted M. xanthus cell flailing when stuck, providing a basis for mechanical analysis.

Purpose of the Study:

• To propose and utilize an elastic model to estimate the force produced by the A-motility engine.
• To determine the bending modulus of a single Myxococcus xanthus cell.
• To provide a quantitative framework for understanding A-type motility.

Main Methods:

• Development of an elastic model based on observed M. xanthus cell flailing.
• Application of the model to estimate force and bending modulus from experimental data.
• Comparison of estimated values with existing data for bacterial mechanics.

Main Results:

• The elastic model estimates a force output of 50-150 pN for A-type motility.
• The estimated bending modulus for M. xanthus is 3 x 10(-14) erg cm.
• The calculated force aligns with slime extrusion predictions, and the bending modulus is significantly lower than in Bacillus subtilis.

Conclusions:

• The proposed elastic model provides a method to quantify A-type motility force and cell mechanics.
• The findings support slime-based mechanisms for A-type motility and reveal distinct cell flexibility in M. xanthus.
• Further experiments are suggested to refine these quantitative estimates.