Bending Instability of Rod-Shaped Bacteria

Area of Science:

• Physics
• Biophysics
• Mechanics of Materials

Background:

• Thin-walled tubes exhibit bending instability, a phenomenon studied for nearly a century.
• The effect of internal pressure on this instability, particularly in biological contexts like bacteria, remains less explored.

Purpose of the Study:

• To theoretically investigate how internal pressure influences the bending instability of thin-walled tubes.
• To understand the mechanical behavior of rod-shaped bacteria under internal turgor pressure and bending stress.

Main Methods:

• Theoretical analysis of the stability of pressurized, thin-walled cylindrical shells under bending.
• Parameter exploration relevant to the dimensions and pressures found in rod-shaped bacteria.

Main Results:

• Internal pressure significantly postpones the onset of bending-induced instability in thin-walled tubes.
• The bending stiffness of the tube wall demonstrates a negligible influence on the instability onset.
• A critical pressure threshold exists beyond which instability is delayed.

Conclusions:

• Internal turgor pressure plays a crucial role in stabilizing rod-shaped bacteria against bending-induced buckling.
• The findings suggest that bending experiments can be utilized to infer turgor pressure in bacteria.
• This research offers a novel approach for non-invasive measurement of internal pressure in microbial cells.