Cell flexibility affects the alignment of model myxobacteria.

Area of Science:

• Microbiology
• Biophysics
• Computational Biology

Background:

• Myxobacteria exhibit complex social behaviors and form multicellular fruiting bodies.
• Cellular alignment is essential for myxobacteria development.
• Previous hypotheses suggested mechanical interactions and cell flexibility drive alignment, lacking experimental evidence.

Purpose of the Study:

• To investigate the role of cell flexibility and motility engine type in myxobacteria population alignment.
• To provide theoretical evidence for or against existing hypotheses on myxobacteria alignment.

Main Methods:

• Development of a computational mass-spring model for flexible, rod-shaped gliding cells.
• Modeling cells with periodic reversals and experimentally measurable parameters (engine force, bending stiffness, drag).
• Simulation of 500 mechanically interacting cells to analyze gliding patterns and population alignment.

Main Results:

• Flexible cells with rear-mounted motility engines (slime extrusion hypothesis) cannot glide along their long axis.
• Rigid, reversing cells can align through mechanical interactions.
• Increased cell flexibility was found to impair population alignment.

Conclusions:

• Cell flexibility and the proposed myxobacteria motility engine mechanism are not conducive to population alignment.
• Mechanical interactions alone can drive alignment in rigid cells, but flexibility is detrimental.
• The findings challenge previous assumptions about the mechanisms underlying myxobacteria collective behavior.