A surface morphology-based inference method for the cell wall elasticity profile in tip-growing cells
Author summary Tip-growing cells can be characterized by their fast growth concentrated at the cellâs apex. Their growth and morphogenesis are tightly regulated processes involving cell wall addition and rearrangement while the cell wall is under stress originating from the cellâs internal turgor pressure. We start by studying the cell wallâs elastic properties, one aspect of the cell growth process. We use a method of marker point tracking across the surface of the tip-growing cell to measure the wallâs elasticity profile. In this work, we present a parameter sensitivity study of this method on synthetic cells and report our results on experimental moss tip-growing cells. Our results suggest that this inference method can reliably measure a cell wall elasticity gradient under combined geometric and mechanical conditions that create elastic strains within 5% at the tip.
đ° "Computational Microscopy Reveals Compound-Specific Flickering Phenotypes of Red Blood Cells Under Flavonoid Exposure"
https://doi.org/doi:10.3390/membranes16030095https://pubmed.ncbi.nlm.nih.gov/41893281/ #Elasticity #Cell[dj] Tony's stretch attacks!
- some charged attacks I dreamt he had, aerial, heavy, and light! Fighting the Hip Chip Clan and the Silent Roar gangs in this one
#spaceRARt #scalieart #human #superhero #elasticity #gamelogicđ° "Modelling the passive and active response of skeletal muscles within the adapted Voigt representation framework"
https://arxiv.org/abs/2603.19723 #Cond-Mat.Soft
#Extracellular #Elasticity #Q-Bio.To
Modelling the passive and active response of skeletal muscles within the adapted Voigt representation framework
We present a constitutive model for the passive and active response of skeletal muscles. At variance with more classical approaches, the model is developed exploiting adapted Voigt representations of strain and stress tensors within the context of nonlinear Cauchy elasticity. This framework allows us to identify non-trivial stress-strain relations in a rather direct way from experimental data, enhancing the mechanical interpretability of the material functions that describe the tissue response and obtaining additional insight on the distinct role of the contractile fibres and of the surrounding extracellular matrix. We propose a two-material model, with an additive splitting of the stress contributions, in which only one component depends on an activation parameter. The constitutive model for the passive behaviour satisfactorily predicts the nonlinear stress response to elongation at different relative orientations with respect to the fibre direction and highlights the dominant role of the extracellular matrix. The activation model, essentially determined by the mechanics of the contractile fibres, captures well the isometric stress response through the prescription of an elasto-plastic evolution of the along-fibre active strain.
đ° "Inter-lamin interactions control meshwork topologyin a polymer-gel model of nuclear lamina"
https://www.biorxiv.org/content/10.64898/2026.03.14.711786v1?rss=1 #Elasticity #Lamin
Interâlamin interactions control meshwork topology in a polymerâgel model of nuclear lamina
The nuclear lamina, composed of supramolecular structures of lamin proteins, is a twoâdimensional protein meshwork that preserves the structural integrity, elasticity, and morphology of the nucleus. LaminsâA/Câtype and Bâtypeâassemble into dynamic, individual but interacting networks with distinct structural properties. Lamina meshwork assembly can be disrupted by lamin mutations in diseases known as laminopathies. Despite extensive experimental insights, the biophysical mechanisms that alter the lamina meshwork topology in health and disease remain relatively poorly understood. In this study, we develop a coarse-grained molecular dynamics (MD) model of lamina selfâassembly, where lamin dimers are modeled as semiflexible polymers confined within an elastic nuclear shell. By systematically interrogating interâlamin and laminâshell association affinities, our simulations reproduce a plethora of experimentally observed lamina architectures, from latticeâlike to fibrous meshwork topologies. This elucidates how the interplay between interâlamin and laminânuclear envelope interactions can shape the nuclear lamina. Importantly, interâlamin interactions can cause a heterogeneous distribution of lamins on the surface and result in large, laminâfree surface domains at sufficiently low lamin-shell affinities. Furthermore, paracrystalline lamin sheets form with increasing propensity for parallel lamin alignment, in addition to the canonical, sticky terminal groups. Overall, our integrative MD and network analysis provide the first explicit polymer physics model of the lamina and demonstrate how lamin interactions may affect the mesoscale architecture of the lamina in disease.
### Competing Interest Statement
The authors have declared no competing interest.
Scientific and Technological Research Council of Turkey, https://ror.org/04w9kkr77, 124N935
đ° "Universal Displacements in Linear Strain-Gradient Elasticity"
https://arxiv.org/abs/2603.05533 #Cond-Mat.Mtrl-Sci
#Physics.Class-Ph
#Elasticity #Matrix
Universal Displacements in Linear Strain-Gradient Elasticity
We study universal displacement fields in three-dimensional linear strain-gradient elasticity within the Toupin-Mindlin first strain-gradient theory. Building on the approach of Yavari (2020), we derive, for each material symmetry class, the universality PDEs obtained by requiring the equilibrium equations (in the absence of body forces) to hold for any material in that class, and we determine the complete set of universal displacements. Using the full symmetry classification together with compact matrix representations of the elasticity tensors, we provide explicit characterizations for all 48 strain-gradient symmetry classes, including centrosymmetric and chiral classes. For several high-symmetry classes, the strain-gradient universality PDEs impose no additional restrictions beyond the classical ones, so the universal displacement families coincide with those of classical linear elasticity (for example, the isotropic classes SO(3) and O(3)). For lower symmetry classes, the strain-gradient universality PDEs can be stricter than their classical counterparts, so the universal displacements form proper subsets of the classical universal displacement families due to additional higher-order differential conditions.
đ° "Differences Between Oral Neutrophils and Neutrophils Isolated From the Blood of Healthy Donors"
https://doi.org/doi:10.1111/omi.70025https://pubmed.ncbi.nlm.nih.gov/41782230/ #Elasticity #Cellstretching to other galaxy! đđ
Do you like how long human Toni can stretch? đ€
#spaceRARt #stretch #human #stretchy #elasticity #cartoonWhy does it keep moving away from me?
#caturdayI #elasticityđ° "Formation of a swelling gel underlies a morphological transition in Bacillus subtilis biofilms"
https://www.biorxiv.org/content/10.64898/2026.02.20.707077v1?rss=1 #Extracellular #ElasticityFormation of a swelling gel underlies a morphological transition in Bacillus subtilis biofilms
Microbes across species and environments form biofilms, living materials composed of cells and extracellular polymers. Biofilm-dwelling cells benefit from emergent soft matter physics that sculpts three-dimensional morphologies and osmotically absorbs nutrients. Although biofilms are modeled as viscoelastic gels, the physical origins of the phase transition underlying their conversion from groups of cells to living gels have not been systematically investigated. Here, we show that Bacillus subtilis biofilms use polymer composition to tune their physical properties and drive gel formation. Using imaging and water immersion experiments with matrix knockout strains, we demonstrate the complementary roles of two polymers in this developmental transition: hydrophilic poly-Îł-glutamate swells colonies by absorbing water and exopolysaccharides serve as effective cross-linkers, causing a sol-gel-like phase transition that imparts structural integrity. With matrix knockout co-culture biofilms, we independently modulate the production of each polymer and reveal a phase space of biofilm morphologies. Colonies that produce both polymers develop macroscopic wrinkles. A thin-film model predicts biofilm wrinkling from swelling-generated internal strain coupled to elasticity. The model reproduces the shape of our observed morphological phase diagram. Our results demonstrate that bacteria leverage gelation to vary their material properties and morphologies, with implications for microbial ecology and engineering living matter.
### Competing Interest Statement
The authors have declared no competing interest.
National Institute of General Medical Sciences, https://ror.org/04q48ey07, R35GM142584
Burroughs Wellcome Fund, https://ror.org/01d35cw23, CASI
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