scholarly journals Polarization of Myosin II Refines Tissue Material Properties to Buffer Mechanical Stress

2019 ◽  
Vol 48 (2) ◽  
pp. 245-260.e7 ◽  
Author(s):  
Maria Duda ◽  
Natalie J. Kirkland ◽  
Nargess Khalilgharibi ◽  
Melda Tozluoglu ◽  
Alice C. Yuen ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Material Properties ◽  
Myosin Ii ◽  
Tissue Material

scholarly journals The interplay of stiffness and force anisotropies drives embryo elongation

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Thanh Thi Kim Vuong-Brender ◽  
Martine Ben Amar ◽  
Julien Pontabry ◽  
Michel Labouesse
Keyword(s):  
Experimental Data ◽  
Material Properties ◽  
Myosin Ii ◽  
Mechanical Forces ◽  
Cell Behaviour ◽  
Cortical Tension ◽  
Actin Cortex ◽  
Stiffness Anisotropy ◽  
Spatiotemporal Changes ◽  
Tissue Material

The morphogenesis of tissues, like the deformation of an object, results from the interplay between their material properties and the mechanical forces exerted on them. The importance of mechanical forces in influencing cell behaviour is widely recognized, whereas the importance of tissue material properties, in particular stiffness, has received much less attention. Using Caenorhabditis elegans as a model, we examine how both aspects contribute to embryonic elongation. Measuring the opening shape of the epidermal actin cortex after laser nano-ablation, we assess the spatiotemporal changes of actomyosin-dependent force and stiffness along the antero-posterior and dorso-ventral axis. Experimental data and analytical modelling show that myosin-II-dependent force anisotropy within the lateral epidermis, and stiffness anisotropy within the fiber-reinforced dorso-ventral epidermis are critical in driving embryonic elongation. Together, our results establish a quantitative link between cortical tension, material properties and morphogenesis of an entire embryo.

scholarly journals The interplay of stiffness and force anisotropies drive embryo elongation

2016 ◽  
Author(s):  
Thanh TK Vuong-Brender ◽  
Martine Ben Amar ◽  
Julien Pontabry ◽  
Michel Labouesse
Keyword(s):  
Material Properties ◽  
Myosin Ii ◽  
Mechanical Forces ◽  
Cell Behaviour ◽  
Cortical Tension ◽  
C Elegans ◽  
Actin Cortex ◽  
Stiffness Anisotropy ◽  
Spatiotemporal Changes ◽  
Tissue Material

AbstractThe morphogenesis of tissues, like the deformation of an object, results from the interplay between their material properties and the mechanical forces exerted on them. Whereas the importance of mechanical forces in influencing cell behaviour is widely recognized, the importance of tissue material properties, in particular stiffness, has received much less attention. Using C. elegans as a model, we examine how both aspects contribute to embryonic elongation. Measuring the opening shape of the epidermal actin cortex after laser nano-ablation, we assess the spatiotemporal changes of actomyosin-dependent force and stiffness along the antero-posterior and dorso-ventral axis. Experimental data and analytical modelling show that myosin II-dependent force anisotropy within the lateral epidermis, and stiffness anisotropy within the fiber-reinforced dorso-ventral epidermis are critical to drive embryonic elongation. Together, our results establish a quantitative link between cortical tension, material properties and morphogenesis of an entire embryo.

The Role of Topology and Tissue Mechanics in Remora Attachment

2014 ◽  
Vol 1648 ◽  
Author(s):  
Michael Culler ◽  
Keri A. Ledford ◽  
Jason H. Nadler
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Tissue Mechanics ◽  
Unit Cell ◽  
Surface Topology ◽  
Finite Element Models ◽  
Cell Geometry ◽  
Critical Step ◽  
Tissue Material

ABSTRACTRemora fish are capable of fast, reversible and reliable adhesion to a wide variety of both natural and artificial marine hosts through a uniquely evolved dorsal pad. This adhesion is partially attributed to suction, which requires a robust seal between the pad interior and the ambient environment. Understanding the behavior of remora adhesion based on measurable surface parameters and material properties is a critical step when creating artificial, bio-inspired devices. In this work, structural and fluid finite element models (FEM) based on a simplified “unit cell” geometry were developed to predict the behavior of the seal with respect to host/remora surface topology and tissue material properties.

Influence of Mechanical Stress at High Temperatures on the Properties of Steels Intended for the Manufacture of Fuel Cladding for Generation IV Reactors

2017 ◽  
Vol 270 ◽  
pp. 246-252
Author(s):  
Zbyněk Špirit ◽  
Michal Chocholoušek ◽  
Marek Šíma
Keyword(s):  
Mechanical Stress ◽  
Material Properties ◽  
Fracture Mechanism ◽  
Nuclear Reactors ◽  
Mechanical Tests ◽  
Basic Material ◽  
Oxide Dispersion ◽  
Fuel Cladding ◽  
Thin Walled ◽  
Miniature Specimens

This paper describes the testing of thin-walled tubes made of oxide dispersion-hardened steels based on yttrium oxides. Series of mechanical and metallographic tests were carried out on the steels to evaluate the basic material properties. These steels are the candidate materials for the manufacture of the fuel cladding for generation IV nuclear reactors. Mechanical tests were performed on miniature specimens of Fe-9Cr and Fe-14Cr steels at 20 °C, 500 °C, and 625 °C under vacuum. Metallographic, fractographic and EBSD analyses were used to describe microstructure and fracture mechanism of the tested materials.

scholarly journals A mechanosensory system governs myosin II accumulation in dividing cells

2012 ◽  
Vol 23 (8) ◽  
pp. 1510-1523 ◽  
Author(s):  
Yee-Seir Kee ◽  
Yixin Ren ◽  
Danielle Dorfman ◽  
Miho Iijima ◽  
Richard Firtel ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Mitotic Spindle ◽  
Asymmetric Cell Division ◽  
Myosin Ii ◽  
Feedback Loops ◽  
Cleavage Furrow ◽  
Dividing Cells ◽  
Centromeric Protein ◽  
Protein Recruitment ◽  
Mechanosensory System

The mitotic spindle is generally considered the initiator of furrow ingression. However, recent studies suggest that furrows can form without spindles, particularly during asymmetric cell division. In Dictyostelium, the mechanoenzyme myosin II and the actin cross-linker cortexillin I form a mechanosensor that responds to mechanical stress, which could account for spindle-independent contractile protein recruitment. Here we show that the regulatory and contractility network composed of myosin II, cortexillin I, IQGAP2, kinesin-6 (kif12), and inner centromeric protein (INCENP) is a mechanical stress–responsive system. Myosin II and cortexillin I form the core mechanosensor, and mechanotransduction is mediated by IQGAP2 to kif12 and INCENP. In addition, IQGAP2 is antagonized by IQGAP1 to modulate the mechanoresponsiveness of the system, suggesting a possible mechanism for discriminating between mechanical and biochemical inputs. Furthermore, IQGAP2 is important for maintaining spindle morphology and kif12 and myosin II cleavage furrow recruitment. Cortexillin II is not directly involved in myosin II mechanosensitive accumulation, but without cortexillin I, cortexillin II's role in membrane–cortex attachment is revealed. Finally, the mitotic spindle is dispensable for the system. Overall, this mechanosensory system is structured like a control system characterized by mechanochemical feedback loops that regulate myosin II localization at sites of mechanical stress and the cleavage furrow.

scholarly journals Multiscale Contribution of Bone Tissue Material Property Heterogeneity to Trabecular Bone Mechanical Behavior

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Ashley A. Lloyd ◽  
Zhen Xiang Wang ◽  
Eve Donnelly
Keyword(s):  
Material Properties ◽  
Experimental Studies ◽  
Heterogeneous Material ◽  
Structural Performance ◽  
Apparent Stiffness ◽  
Potential Contributor ◽  
Homogeneous Models ◽  
Fracture History ◽  
Tissue Material ◽  
Better Than

Heterogeneity of material properties is an important potential contributor to bone fracture resistance because of its putative contribution to toughness, but establishing the contribution of heterogeneity to fracture risk is still in an incipient stage. Experimental studies have demonstrated changes in distributions of compositional and nanomechanical properties with fragility fracture history, disease, and pharmacologic treatment. Computational studies have demonstrated that models with heterogeneous material properties predict apparent stiffness moderately better than homogeneous models and show greater energy dissipation. Collectively, these results suggest that microscale material heterogeneity affects not only microscale mechanics but also structural performance at larger length scales.

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