Surface architecture of Neisseria meningitidis capsule and outer membrane as revealed by atomic force microscopy

Manno, D.; Talà, Adelfia; Calcagnile, Matteo; Resta, Silvia Caterina; Alifano, Pietro; Serra, A.

doi:10.1016/j.resmic.2021.103865

Cited by 4 publications

(2 citation statements)

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“…Several methods of applying mechanical loads to individual live bacteria have been used to date. Atomic force microscopy involves the placement of probes in direct contact with the cell surface and provides force and deflection information that can be used to measure the Young’s modulus of whole cell (composite of the cell envelope and cytoplasm) or, with appropriate modeling, the Young’s modulus of cell envelope alone. − Alternatively, whole bacteria may be submitted to bending tests by securing one end of the cell, inducing filamentous growth, and applying a bending load using either optical tweezers or transverse fluid flow in a microfluidic chamber to determine flexural rigidity and calculate cell envelope Young’s modulus. − Lastly, the Young’s modulus of the cell envelope can be inferred by growing bacteria within an agarose gel of known stiffness by measuring the rate of cell elongation . The Young’s modulus of the cell envelope of Escherichia coli determined using these approaches spans from 2 to 18 MPa (Table ).…”

Section: Introductionmentioning

confidence: 99%

Determining the Young’s Modulus of the Bacterial Cell Envelope

Lee,

Jha,

Harper

et al. 2024

ACS Biomater. Sci. Eng.

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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 Escherichia coli range from 2 to 18 MPa. We 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 Vibrio cholerae and Staphylococcus 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 values of the cell envelope were 2.06 ± 0.04 MPa for E. coli, 0.84 ± 0.02 MPa for E. coli treated with a chemical (A22) 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 examination of 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 behind differences in cell envelope Young's modulus among bacterial species and strains.

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Section: Introductionmentioning

confidence: 99%

Determining the Young’s Modulus of the Bacterial Cell Envelope

Lee,

Jha,

Harper

et al. 2024

ACS Biomater. Sci. Eng.

View full text Add to dashboard Cite

show abstract

“…Several methods of applying mechanical loads to individual, live bacteria have been used to date. Atomic force microscopy involves the placement of probes in direct contact with the cell surface and provides force and deflection information that can be used to measure the Young's modulus of whole cell (composite of the cell envelope and cytoplasm) or, with appropriate modeling, the Young's modulus of cell envelope alone [9][10][11][12][13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Determining the Young’s Modulus of the Bacterial Cell Envelope

Lee,

Jha,

Harper

et al. 2024

Preprint

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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 Youngs 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 Youngs 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 Youngs modulus from observed deformations. The Youngs 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 Youngs modulus among bacteria species and strains.

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Lopsided elastic dumbbell suspension

Phan-Thien,

Kanso,

Giacomin

2024

Physics of Fluids

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We derive the constitutive equation for a suspension of lopsided Hookean dumbbells. By lopsided, we mean that one bead is larger than the other. We find that all results derived for symmetric Hookean dumbbells can be taken over for lopsided ones by replacing 2/ζ with 1/ζ1+1/ζ2, where ζ and ζ1 and ζ2 are the bead friction coefficients for the symmetric dumbbell beads and for the first and second beads of the lopsided dumbbell, respectively.

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Surface architecture of Neisseria meningitidis capsule and outer membrane as revealed by atomic force microscopy

Cited by 4 publications

References 47 publications

Determining the Young’s Modulus of the Bacterial Cell Envelope

Determining the Young’s Modulus of the Bacterial Cell Envelope

Determining the Young’s Modulus of the Bacterial Cell Envelope

Lopsided elastic dumbbell suspension

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