Samuel Bell, Joseph Ackermann, Ananyo Maitra, Raphael Voituriez
Growing experimental evidence shows that cell monolayers can induce long-lived perturbations to their environment, akin to footprints, which in turn influence the global dynamics of the system. Inspired by these observations, we propose a comprehensive theoretical framework to describe systems where an active field dynamically interacts with a non-advected footprint field, deposited by the active field. We derive the corresponding general hydrodynamics for both polar and nematic fields. Our findings reveal that the dynamic coupling to a footprint field induces remarkable effects absent in classical active hydrodynamics, such as symmetry-dependent modifications to the isotropic-ordered transition, which may manifest as either second-order or first-order, alterations in spontaneous flow transitions, potentially resulting in oscillating flows and rotating fields, and initial condition-dependent aging dynamics characterized by long-lived transient states. Our results suggest that footprint deposition could be a key mechanism determining the dynamical phases of cellular systems, or more generally active systems inducing long-lived perturbations to their environment.
{"title":"Ordering, spontaneous flows and aging in active fluids depositing tracks","authors":"Samuel Bell, Joseph Ackermann, Ananyo Maitra, Raphael Voituriez","doi":"arxiv-2409.05195","DOIUrl":"https://doi.org/arxiv-2409.05195","url":null,"abstract":"Growing experimental evidence shows that cell monolayers can induce\u0000long-lived perturbations to their environment, akin to footprints, which in\u0000turn influence the global dynamics of the system. Inspired by these\u0000observations, we propose a comprehensive theoretical framework to describe\u0000systems where an active field dynamically interacts with a non-advected\u0000footprint field, deposited by the active field. We derive the corresponding\u0000general hydrodynamics for both polar and nematic fields. Our findings reveal\u0000that the dynamic coupling to a footprint field induces remarkable effects\u0000absent in classical active hydrodynamics, such as symmetry-dependent\u0000modifications to the isotropic-ordered transition, which may manifest as either\u0000second-order or first-order, alterations in spontaneous flow transitions,\u0000potentially resulting in oscillating flows and rotating fields, and initial\u0000condition-dependent aging dynamics characterized by long-lived transient\u0000states. Our results suggest that footprint deposition could be a key mechanism\u0000determining the dynamical phases of cellular systems, or more generally active\u0000systems inducing long-lived perturbations to their environment.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During development and under normal physiological conditions, biological tissues are continuously subjected to substantial mechanical stresses. In response to large deformations cells in a tissue must undergo multicellular rearrangements in order to maintain integrity and robustness. However, how these events are connected in time and space remains unknown. Here, using computational and theoretical modeling, we studied the mechanical plasticity of epithelial monolayers under large deformations. Our results demonstrate that the jamming-unjamming (solid-fluid) transition in tissues can vary significantly depending on the degree of deformation, implying that tissues are highly unconventional materials. Using analytical modeling, we elucidate the origins of this behavior. We also demonstrate how a tissue accommodates large deformations through a collective series of rearrangements, which behave similarly to avalanches in non-living materials. We find that these tissue avalanches are governed by stress redistribution and the spatial distribution of vulnerable spots. Finally, we propose a simple and experimentally accessible framework to predict avalanches and infer tissue mechanical stress based on static images.
{"title":"Origin of yield stress and mechanical plasticity in biological tissues","authors":"Anh Q. Nguyen, Junxiang Huang, Dapeng Bi","doi":"arxiv-2409.04383","DOIUrl":"https://doi.org/arxiv-2409.04383","url":null,"abstract":"During development and under normal physiological conditions, biological\u0000tissues are continuously subjected to substantial mechanical stresses. In\u0000response to large deformations cells in a tissue must undergo multicellular\u0000rearrangements in order to maintain integrity and robustness. However, how\u0000these events are connected in time and space remains unknown. Here, using\u0000computational and theoretical modeling, we studied the mechanical plasticity of\u0000epithelial monolayers under large deformations. Our results demonstrate that\u0000the jamming-unjamming (solid-fluid) transition in tissues can vary\u0000significantly depending on the degree of deformation, implying that tissues are\u0000highly unconventional materials. Using analytical modeling, we elucidate the\u0000origins of this behavior. We also demonstrate how a tissue accommodates large\u0000deformations through a collective series of rearrangements, which behave\u0000similarly to avalanches in non-living materials. We find that these tissue\u0000avalanches are governed by stress redistribution and the spatial distribution\u0000of vulnerable spots. Finally, we propose a simple and experimentally accessible\u0000framework to predict avalanches and infer tissue mechanical stress based on\u0000static images.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ion channels are protein structures that facilitate the selective passage of ions across the membrane cells of living organisms. They are known for their high conductance and high selectivity. The precise mechanism between these two seemingly contradicting features is not yet firmly established. One possible candidate is the quantum coherence. In this work we study the quantum model of the soft knock-on conduction using the Lindblad equation taking into account the non-hermiticity of the model. We show that the model exhibits a regime in which high conductance coexists with high coherence. Our findings second the role of quantum effects in the transport properties of the ion channels.
{"title":"Quantum features of the transport through ion channels in the soft knock-on model","authors":"Mateusz Polakowski, Miłosz Panfil","doi":"arxiv-2409.03497","DOIUrl":"https://doi.org/arxiv-2409.03497","url":null,"abstract":"Ion channels are protein structures that facilitate the selective passage of\u0000ions across the membrane cells of living organisms. They are known for their\u0000high conductance and high selectivity. The precise mechanism between these two\u0000seemingly contradicting features is not yet firmly established. One possible\u0000candidate is the quantum coherence. In this work we study the quantum model of\u0000the soft knock-on conduction using the Lindblad equation taking into account\u0000the non-hermiticity of the model. We show that the model exhibits a regime in\u0000which high conductance coexists with high coherence. Our findings second the\u0000role of quantum effects in the transport properties of the ion channels.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jonathan Bauermann, Giacomo Bartolucci, Job Boekhoven, Frank Jülicher, Christoph A. Weber
Emulsions ripen with an average droplet size increasing in time. In chemically active emulsions, coarsening can be absent, leading to a non-equilibrium steady state with mono-disperse droplet sizes. By considering a minimal model for phase separation and chemical reactions maintained away from equilibrium, we show that there is a critical transition in the conserved quantity between two classes of chemically active droplets: intensive and extensive ones. Single intensive active droplets reach a stationary size mainly controlled by the reaction-diffusion length scales. Intensive droplets in an emulsion interact only weakly, and the stationary size of a single droplet approximately sets the size of each droplet. On the contrary, the size of a single extensive active droplet scales with the system size, similar to passive phases. In an emulsion of many extensive droplets, their sizes become stationary only due to interactions among them. We discuss how the critical transition between intensive and extensive active droplets affects shape instabilities, including the division of active droplets, paving the way for the observation of successive division events in chemically active emulsions
{"title":"Critical transition between intensive and extensive active droplets","authors":"Jonathan Bauermann, Giacomo Bartolucci, Job Boekhoven, Frank Jülicher, Christoph A. Weber","doi":"arxiv-2409.03629","DOIUrl":"https://doi.org/arxiv-2409.03629","url":null,"abstract":"Emulsions ripen with an average droplet size increasing in time. In\u0000chemically active emulsions, coarsening can be absent, leading to a\u0000non-equilibrium steady state with mono-disperse droplet sizes. By considering a\u0000minimal model for phase separation and chemical reactions maintained away from\u0000equilibrium, we show that there is a critical transition in the conserved\u0000quantity between two classes of chemically active droplets: intensive and\u0000extensive ones. Single intensive active droplets reach a stationary size mainly\u0000controlled by the reaction-diffusion length scales. Intensive droplets in an\u0000emulsion interact only weakly, and the stationary size of a single droplet\u0000approximately sets the size of each droplet. On the contrary, the size of a\u0000single extensive active droplet scales with the system size, similar to passive\u0000phases. In an emulsion of many extensive droplets, their sizes become\u0000stationary only due to interactions among them. We discuss how the critical\u0000transition between intensive and extensive active droplets affects shape\u0000instabilities, including the division of active droplets, paving the way for\u0000the observation of successive division events in chemically active emulsions","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tomoei Takahashi, George Chikenji, Kei Tokita, Yoshiyuki Kabashima
How typical elements that shape organisms, such as protein secondary structures, have evolved, or how evolutionarily susceptible/resistant they are to environmental changes, are significant issues in evolutionary biology, structural biology, and biophysics. According to Darwinian evolution, natural selection and genetic mutations are the primary drivers of biological evolution. However, the concept of ``robustness of the phenotype to environmental perturbations across successive generations,'' which seems crucial from the perspective of natural selection, has not been formalized or analyzed. In this study, through Bayesian learning and statistical mechanics we formalize the stability of the free energy in the space of amino acid sequences that can design particular protein structure against perturbations of the chemical potential of water surrounding a protein as such robustness. This evolutionary stability is defined as a decreasing function of a quantity analogous to the susceptibility in the statistical mechanics of magnetic bodies specific to the amino acid sequence of a protein. Consequently, in a two-dimensional square lattice protein model composed of 36 residues, we found that as we increase the stability of the free energy against perturbations in environmental conditions, the structural space shows a steep step-like reduction. Furthermore, lattice protein structures with higher stability against perturbations in environmental conditions tend to have a higher proportion of $alpha$-helices and a lower proportion of $beta$-sheets. The latter result shows that protein structures rich in $alpha$-helices are more robust to environmental perturbations through successive generations than those rich in $beta$-sheets.
{"title":"Alpha helices are more evolutionarily robust to environmental perturbations than beta sheets: Bayesian learning and statistical mechanics to protein evolution","authors":"Tomoei Takahashi, George Chikenji, Kei Tokita, Yoshiyuki Kabashima","doi":"arxiv-2409.03297","DOIUrl":"https://doi.org/arxiv-2409.03297","url":null,"abstract":"How typical elements that shape organisms, such as protein secondary\u0000structures, have evolved, or how evolutionarily susceptible/resistant they are\u0000to environmental changes, are significant issues in evolutionary biology,\u0000structural biology, and biophysics. According to Darwinian evolution, natural\u0000selection and genetic mutations are the primary drivers of biological\u0000evolution. However, the concept of ``robustness of the phenotype to\u0000environmental perturbations across successive generations,'' which seems\u0000crucial from the perspective of natural selection, has not been formalized or\u0000analyzed. In this study, through Bayesian learning and statistical mechanics we\u0000formalize the stability of the free energy in the space of amino acid sequences\u0000that can design particular protein structure against perturbations of the\u0000chemical potential of water surrounding a protein as such robustness. This\u0000evolutionary stability is defined as a decreasing function of a quantity\u0000analogous to the susceptibility in the statistical mechanics of magnetic bodies\u0000specific to the amino acid sequence of a protein. Consequently, in a\u0000two-dimensional square lattice protein model composed of 36 residues, we found\u0000that as we increase the stability of the free energy against perturbations in\u0000environmental conditions, the structural space shows a steep step-like\u0000reduction. Furthermore, lattice protein structures with higher stability\u0000against perturbations in environmental conditions tend to have a higher\u0000proportion of $alpha$-helices and a lower proportion of $beta$-sheets. The\u0000latter result shows that protein structures rich in $alpha$-helices are more\u0000robust to environmental perturbations through successive generations than those\u0000rich in $beta$-sheets.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Biological functionality of cellular aggregates is largely influenced by the activity and displacements of individual constituent cells. From a theoretical perspective this activity can be characterized by hydrodynamic transport coefficients of diffusivity and conductivity. Motivated by the clustering dynamics of bacterial microcolonies we propose a model of active multicellular aggregates and use recently developed macroscopic fluctuation theory to derive a fluctuating hydrodynamics for this model system. Both semi-analytic theory and microscopic simulations show that the hydrodynamic transport coefficients are affected by non-equilibrium microscopic parameters and significantly decrease inside of the clusters. We further find that the Einstein relation connecting the transport coefficients and fluctuations breaks down in the parameter regime where the detailed balance is not satisfied. This study offers valuable tools for experimental investigation of hydrodynamic transport in other systems of cellular aggregates such as tumor spheroids and organoids.
{"title":"Fluctuating Hydrodynamics Describes Transport in Cellular Aggregates","authors":"Subhadip Chakraborti, Vasily Zaburdaev","doi":"arxiv-2409.03039","DOIUrl":"https://doi.org/arxiv-2409.03039","url":null,"abstract":"Biological functionality of cellular aggregates is largely influenced by the\u0000activity and displacements of individual constituent cells. From a theoretical\u0000perspective this activity can be characterized by hydrodynamic transport\u0000coefficients of diffusivity and conductivity. Motivated by the clustering\u0000dynamics of bacterial microcolonies we propose a model of active multicellular\u0000aggregates and use recently developed macroscopic fluctuation theory to derive\u0000a fluctuating hydrodynamics for this model system. Both semi-analytic theory\u0000and microscopic simulations show that the hydrodynamic transport coefficients\u0000are affected by non-equilibrium microscopic parameters and significantly\u0000decrease inside of the clusters. We further find that the Einstein relation\u0000connecting the transport coefficients and fluctuations breaks down in the\u0000parameter regime where the detailed balance is not satisfied. This study offers\u0000valuable tools for experimental investigation of hydrodynamic transport in\u0000other systems of cellular aggregates such as tumor spheroids and organoids.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amir Shee, Vidur Sabharwal, Sandhya P. Koushika, Amitabha Nandi, Debasish Chaudhuri
Cargo distribution within eukaryotic cells relies on the active transport mechanisms driven by molecular motors. Despite their critical role, the intricate relationship between motor transport properties and cargo binding - and its impact on motor distribution - remains inadequately understood. Additionally, improper regulation of ubiquitination, a pivotal post-translational modification that affects protein degradation, activation, and localization, is associated with several neurodegenerative diseases. Recent data showed that ubiquitination can alter motor-cargo binding of the Kinesin-3 motor UNC-104 / KIF1A that transports synaptic vesicles. To investigate how ubiquitin-like modifications affect motor protein function, particularly cargo binding, transport properties, and distribution, we utilize the PLM neuron of C. elegans as a model system. Using fluorescent microscopy, we assess the distribution of cargo-bound UNC-104 motors along the axon and probe their dynamics using FRAP experiments. We model cargo binding kinetics with a Master equation and motor density dynamics using a Fokker-Planck approach. Our combined experimental and theoretical analysis reveals that ubiquitin-like knockdowns enhance UNC-104's cooperative binding to its cargo. However, these modifications do not affect UNC-104's transport properties, such as processivity and diffusivity. Thus, while ubiquitin-like modifications significantly impact the cargo-binding of UNC-104, they do not alter its transport dynamics, keeping the homeostatic distribution of UNC-104 unchanged.
{"title":"UNC-104 transport properties are robust and independent of changes in its cargo binding","authors":"Amir Shee, Vidur Sabharwal, Sandhya P. Koushika, Amitabha Nandi, Debasish Chaudhuri","doi":"arxiv-2409.02655","DOIUrl":"https://doi.org/arxiv-2409.02655","url":null,"abstract":"Cargo distribution within eukaryotic cells relies on the active transport\u0000mechanisms driven by molecular motors. Despite their critical role, the\u0000intricate relationship between motor transport properties and cargo binding -\u0000and its impact on motor distribution - remains inadequately understood.\u0000Additionally, improper regulation of ubiquitination, a pivotal\u0000post-translational modification that affects protein degradation, activation,\u0000and localization, is associated with several neurodegenerative diseases. Recent\u0000data showed that ubiquitination can alter motor-cargo binding of the Kinesin-3\u0000motor UNC-104 / KIF1A that transports synaptic vesicles. To investigate how\u0000ubiquitin-like modifications affect motor protein function, particularly cargo\u0000binding, transport properties, and distribution, we utilize the PLM neuron of\u0000C. elegans as a model system. Using fluorescent microscopy, we assess the\u0000distribution of cargo-bound UNC-104 motors along the axon and probe their\u0000dynamics using FRAP experiments. We model cargo binding kinetics with a Master\u0000equation and motor density dynamics using a Fokker-Planck approach. Our\u0000combined experimental and theoretical analysis reveals that ubiquitin-like\u0000knockdowns enhance UNC-104's cooperative binding to its cargo. However, these\u0000modifications do not affect UNC-104's transport properties, such as\u0000processivity and diffusivity. Thus, while ubiquitin-like modifications\u0000significantly impact the cargo-binding of UNC-104, they do not alter its\u0000transport dynamics, keeping the homeostatic distribution of UNC-104 unchanged.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Revaz D. Chachanidze, Othmane Aouane, Jens Harting, Christian Wagner, Marc Leonetti
Margination, a fundamental process in which leukocytes migrate from the flowing blood to the vessel wall, is well-documented in physiology. However, it is still an open question on how the differences in cell size and stiffness of white and red cells contribute to this phenomenon. To investigate the specific influence of cell stiffness, we conduct experimental and numerical studies on the segregation of a binary mixture of artificially stiffened red blood cells within a suspension of healthy cells. The resulting distribution of stiffened cells within the channel is found to depend on the channel geometry, as demonstrated with slit, rectangular, and cylindrical cross-sections. Notably, an unexpected central peak in the distribution of stiffened RBCs, accompanied by fourfold peaks at the corners, emerges in agreement with simulations. Our results unveil a non-monotonic variation in segregation/margination concerning hematocrit and flow rate, challenging the prevailing belief that higher flow rates lead to enhanced margination.
{"title":"Margination of artificially stiffened red blood cells","authors":"Revaz D. Chachanidze, Othmane Aouane, Jens Harting, Christian Wagner, Marc Leonetti","doi":"arxiv-2409.02776","DOIUrl":"https://doi.org/arxiv-2409.02776","url":null,"abstract":"Margination, a fundamental process in which leukocytes migrate from the\u0000flowing blood to the vessel wall, is well-documented in physiology. However, it\u0000is still an open question on how the differences in cell size and stiffness of\u0000white and red cells contribute to this phenomenon. To investigate the specific\u0000influence of cell stiffness, we conduct experimental and numerical studies on\u0000the segregation of a binary mixture of artificially stiffened red blood cells\u0000within a suspension of healthy cells. The resulting distribution of stiffened\u0000cells within the channel is found to depend on the channel geometry, as\u0000demonstrated with slit, rectangular, and cylindrical cross-sections. Notably,\u0000an unexpected central peak in the distribution of stiffened RBCs, accompanied\u0000by fourfold peaks at the corners, emerges in agreement with simulations. Our\u0000results unveil a non-monotonic variation in segregation/margination concerning\u0000hematocrit and flow rate, challenging the prevailing belief that higher flow\u0000rates lead to enhanced margination.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The growth of plants is a hydromechanical phenomenon in which cells enlarge by absorbing water, while their walls expand and remodel under turgor-induced tension. In multicellular tissues, where cells are mechanically interconnected, morphogenesis results from the combined effect of local cell growths, which reflects the action of heterogeneous mechanical, physical, and chemical fields, each exerting varying degrees of nonlocal influence within the tissue. To describe this process, we propose a physical field theory of plant growth. This theory treats the tissue as a poromorphoelastic body, namely a growing poroelastic medium, where growth arises from pressure-induced deformations and osmotically-driven imbibition of the tissue. From this perspective, growing regions correspond to hydraulic sinks, leading to the possibility of complex non-local regulations, such as water competition and growth-induced water potential gradients. More in general, this work aims to establish foundations for a mechanistic, mechanical field theory of morphogenesis in plants, where growth arises from the interplay of multiple physical fields, and where biochemical regulations are integrated through specific physical parameters.
{"title":"Hydromechanical field theory of plant morphogenesis","authors":"Hadrien Oliveri, Ibrahim Cheddadi","doi":"arxiv-2409.02775","DOIUrl":"https://doi.org/arxiv-2409.02775","url":null,"abstract":"The growth of plants is a hydromechanical phenomenon in which cells enlarge\u0000by absorbing water, while their walls expand and remodel under turgor-induced\u0000tension. In multicellular tissues, where cells are mechanically interconnected,\u0000morphogenesis results from the combined effect of local cell growths, which\u0000reflects the action of heterogeneous mechanical, physical, and chemical fields,\u0000each exerting varying degrees of nonlocal influence within the tissue. To\u0000describe this process, we propose a physical field theory of plant growth. This\u0000theory treats the tissue as a poromorphoelastic body, namely a growing\u0000poroelastic medium, where growth arises from pressure-induced deformations and\u0000osmotically-driven imbibition of the tissue. From this perspective, growing\u0000regions correspond to hydraulic sinks, leading to the possibility of complex\u0000non-local regulations, such as water competition and growth-induced water\u0000potential gradients. More in general, this work aims to establish foundations\u0000for a mechanistic, mechanical field theory of morphogenesis in plants, where\u0000growth arises from the interplay of multiple physical fields, and where\u0000biochemical regulations are integrated through specific physical parameters.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A remarkable feature of the elephant trunk is the pronounced wrinkling that enables its great flexibility. Here, we devise a general mathematical model that accounts for characteristic skin wrinkles formed during morphogenesis in elephant trunk. Using physically realistic parameters and operating within the theoretical framework of nonlinear morphoelasticity, we elucidate analytically and numerically the effect of skin thickness, relative stiffness and differential growth on the physiological pattern of transverse wrinkles distributed along the trunk. We conclude that, since the skin and muscle components have similar material properties, geometric parameters, such as curvature, play important roles. In particular, our model predicts that, in the proximal region close to the skull, where curvature is lower, fewer wrinkles form and sooner than in the distal narrower region where more wrinkles develop. Similarly, less wrinkling is found on the ventral side, which is flatter, compared to the dorsal side. In summary, the mechanical compatibility between the skin and the muscle enables them to grow seamlessly, while the wrinkled skin acts as a protective barrier that is both thicker and more flexible than the unwrinkled skin.
{"title":"Elephant trunk wrinkles: A mathematical model of function and form","authors":"Yang Liu, Alain Goriely, L. Angela Mihai","doi":"arxiv-2409.03075","DOIUrl":"https://doi.org/arxiv-2409.03075","url":null,"abstract":"A remarkable feature of the elephant trunk is the pronounced wrinkling that\u0000enables its great flexibility. Here, we devise a general mathematical model\u0000that accounts for characteristic skin wrinkles formed during morphogenesis in\u0000elephant trunk. Using physically realistic parameters and operating within the\u0000theoretical framework of nonlinear morphoelasticity, we elucidate analytically\u0000and numerically the effect of skin thickness, relative stiffness and\u0000differential growth on the physiological pattern of transverse wrinkles\u0000distributed along the trunk. We conclude that, since the skin and muscle\u0000components have similar material properties, geometric parameters, such as\u0000curvature, play important roles. In particular, our model predicts that, in the\u0000proximal region close to the skull, where curvature is lower, fewer wrinkles\u0000form and sooner than in the distal narrower region where more wrinkles develop.\u0000Similarly, less wrinkling is found on the ventral side, which is flatter,\u0000compared to the dorsal side. In summary, the mechanical compatibility between\u0000the skin and the muscle enables them to grow seamlessly, while the wrinkled\u0000skin acts as a protective barrier that is both thicker and more flexible than\u0000the unwrinkled skin.","PeriodicalId":501040,"journal":{"name":"arXiv - PHYS - Biological Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142213133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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