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Bacteria experience substantial physical forces in their natural environment including forces caused by osmotic pressure, growth in constrained spaces, and fluid shear. The cell envelope is the primary load-carrying structure of bacteria, but the mechanical properties of the cell envelope are poorly understood; reports of Young’s modulus of the cell envelope of E. coli are widely range from 2 MPa to 18 MPa. We have developed a microfluidic system to apply mechanical loads to hundreds of bacteria at once and demonstrated the utility of the approach for evaluating whole-cell stiffness. Here we extend this technique to determine Young’s modulus of the cell envelope of E. coli and of the pathogens V. cholerae and S. aureus. An optimization-based inverse finite element analysis was used to determine the cell envelope Young’s modulus from observed deformations. The Young’s modulus of the cell envelope was 2.06±0.04 MPa for E. coli, 0.84±0.02 MPa for E. coli treated with a chemical known to reduce cell stiffness, 0.12±0.03 MPa for V. cholerae, and 1.52±0.06 MPa for S. aureus (mean ± SD). The microfluidic approach allows examining hundreds of cells at once and is readily applied to Gram-negative and Gram-positive organisms as well as rod-shaped and cocci cells, allowing further examination of the structural causes of differences in cell envelope Young's modulus among bacteria species and strains.
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Molecular Modeling and Simulation of the Mycobacterial Cell Envelope: From Individual Components to Cell Envelope Assemblies
- Award ID(s):
- 2111728
- PAR ID:
- 10479580
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- The Journal of Physical Chemistry B
- Volume:
- 127
- Issue:
- 51
- ISSN:
- 1520-6106
- Format(s):
- Medium: X Size: p. 10941-10949
- Size(s):
- p. 10941-10949
- Sponsoring Org:
- National Science Foundation
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