Mechanical double layer model for Saccharomyces Cerevisiae cell wall

Abstract

The elastic modulus of the Baker's yeast (Saccharomyces cerevisiae) cell wall reported in studies using atomic force microscopy (AFM) is two orders of magnitude lower than that obtained using whole cell compression by micromanipulation. Using finite element modelling, it is shown that Hertz-Sneddon analysis cannot be applied to AFM indentation data for single layer core-shell structures. In addition, the Reissner solution for shallow homogeneous spheres is not appropriate for thick walls such as those of yeast cells. In order to explain yeast compression measurements at different length scales, a double layer wall model is presented considering a soft external layer composed of mannoproteins, and a stiff inner layer of β-glucan fibres and chitin. Under this model, previous AFM studies using sharp indenters provide reasonable estimates of the external layer elastic modulus, while micromanipulation provides the total stiffness of the cell wall. Data from both measurements are combined to estimate the mechanical properties of the inner stiff layer.

Fast automated processing of AFM PeakForce curves to evaluate spatially resolved Young modulus and stiffness of turgescent cells

“…57 In particular, eqn (1) and 7render impossible the differentiated evaluations of the respective elastic and entropic contributions of the outer cell membrane and of the surrounding lipopolysaccharidic cushion (if relevant, see discussion in Section 3.5) or any other surface biomolecules 65,66 to the here-obtained effective Young modulus E. Alternatives do exist, as proposed e.g. by Gaboriaud et al, 14 Guz et al, 67 Mercade-Prieto et al 68 for bacteria, brush-like decorated human cells, and yeasts, respectively. In turn, E moduli data should necessarily be viewed as qualitative.…”

Anisotropic Blistering Instability of Highly Ellipsoidal Shells

“…In this setting, the determination of the force-displacement relationship is important because of its application to atomic force microscopy (AFM) measurements of viruses [10] as well as yeast and other cells [11][12][13]. Recently, this work has been extended to the indentation of ellipsoidal shells from both theoretical [14] and experimental points of view [15].…”

Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis

“…The cell wall was considered in both models as a single-layered thin shell, but the yeast cell wall consists of two distinct layers: an electron-dense outer layer enriched in mannoproteins and an electron-transparent polysaccharide layer. The incorporation of an elastic double-layer model [ 68 ] may be worth considering for a more comprehensive model. While the model described the relation between elasticity patterns and shape changes very well, the establishment and regulation of elasticity patterns reported herein remain unclear.…”