1,316 results match your criteria pulling forces

Optoregulated force application to cellular receptors using molecular motors.

Nat Commun 2021 06 11;12(1):3580. Epub 2021 Jun 11.

INM - Leibniz Institute for New Materials, Saarbrücken, Germany.

Progress in our understanding of mechanotransduction events requires noninvasive methods for the manipulation of forces at molecular scale in physiological environments. Inspired by cellular mechanisms for force application (i.e. Read More

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Planar polarization of cilia in the zebrafish floor-plate involves Par3-mediated posterior localization of highly motile basal bodies.

Development 2021 Jun 9. Epub 2021 Jun 9.

Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005, Paris, France.

Epithelial cilia, whether motile or primary, often display an off-centered planar localization within the apical cell surface. This form of planar cell polarity (PCP) involves the asymmetric positioning of the ciliary basal body (BB). Using the mono-ciliated epithelium of the embryonic zebrafish floor-plate, we investigated the dynamics and mechanisms of BB polarization by live-imaging. Read More

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Nonlinear amplification of adhesion forces in interleaved books.

Eur Phys J E Soft Matter 2021 May 28;44(5):71. Epub 2021 May 28.

Laboratoire de physique des solides, CNRS, Université Paris-Saclay, Orsay, France.

It is nearly impossible to separate two interleaved phonebooks by pulling their spines. The very slight force exerted by the outer sheets of the assembly is amplified as the exponential of the square of the number of sheets, meaning that even a small number of sheets can create a highly resistant system. We present a systematic and detailed study of the influences of the normal external force and the geometrical parameters of the booklets on the assembly strength. Read More

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Biomechanics of chromosome alignment at the spindle midplane.

Curr Biol 2021 May;31(10):R574-R585

Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia. Electronic address:

During metaphase, chromosomes are aligned in a lineup at the equatorial plane of the spindle to ensure synchronous poleward movement of chromatids in anaphase and proper nuclear reformation at the end of mitosis. Chromosome alignment relies on microtubules, several types of motor protein and numerous other microtubule-associated and regulatory proteins. Because of the multitude of players involved, the mechanisms of chromosome alignment are still under debate. Read More

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MD Simulations on a Well-Built Docking Model Reveal Fine Mechanical Stability and Force-Dependent Dissociation of Mac-1/GPIbα Complex.

Front Mol Biosci 2021 22;8:638396. Epub 2021 Apr 22.

Institute of Biomechanics/School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China.

Interaction of leukocyte integrin macrophage-1 antigen (Mac-1) to platelet glycoprotein Ibα (GPIbα) is critical for platelet-leukocyte crosstalk in hemostasis and inflammatory responses to vessel injuries under hemodynamic environments. The mechano-regulation and its molecular basis for binding of Mac-1 to GPIbα remain unclear, mainly coming from the lack of crystal structure of the Mac-1/GPIbα complex. We herein built a Mac-1/GPIbα complex model through a novel computer strategy, which included a flexible molecular docking and system equilibrium followed by a "force-ramp + snapback" molecular dynamics (MD) simulation. Read More

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Sugar-Pucker Force-Induced Transition in Single-Stranded DNA.

Int J Mol Sci 2021 Apr 29;22(9). Epub 2021 Apr 29.

Small Biosystems Lab, Condensed Matter Physics Department, Universitat de Barcelona, Carrer de Martí i Franquès 1, 08028 Barcelona, Spain.

The accurate knowledge of the elastic properties of single-stranded DNA (ssDNA) is key to characterize the thermodynamics of molecular reactions that are studied by force spectroscopy methods where DNA is mechanically unfolded. Examples range from DNA hybridization, DNA ligand binding, DNA unwinding by helicases, etc. To date, ssDNA elasticity has been studied with different methods in molecules of varying sequence and contour length. Read More

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Optically Driven Gold Nanoparticles Seed Surface Bubble Nucleation in Plasmonic Suspension.

Nano Lett 2021 May 3. Epub 2021 May 3.

Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States.

Photothermal surface bubbles play important roles in applications like microfluidics and biosensing, but their formation on transparent substrates immersed in a plasmonic nanoparticle (NP) suspension has an unknown origin. Here, we reveal NPs deposited on the transparent substrate by optical forces are responsible for the nucleation of such photothermal surface bubbles. We show the surface bubble formation is always preceded by the optically driven NPs moving toward and deposited to the surface. Read More

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Maximum strength levels for pulling and pushing handleless cartons in warehousing tasks.

Ergonomics 2021 May 19:1-9. Epub 2021 May 19.

Department of Industrial Engineering and Management, Ming Chi University of Technology, New Taipei, Taiwan.

This study examined the variation in individuals' static maximum forward pushing and backward pulling (FPBP) strength for handleless cartons under different task conditions. Thirty young Taiwanese men were recruited as participants and were requested to perform maximum FPBP exertion tests under four exertion heights (50, 80, 110, and 140 cm), two types of hand contact (bare hands and gloves), and two carton widths (40 and 60 cm). The results of this study indicated that the pushing strength for handleless cartons was almost twice the pulling strength for all exertion heights. Read More

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Bendy to the bone: Links between vertebral morphology and waterfall climbing in amphidromous gobioid fishes.

J Anat 2021 Apr 29. Epub 2021 Apr 29.

Department of Biological Sciences, Clemson University, Clemson, SC, USA.

Locomotor force production imposes strong demands on organismal form. Thus, the evolution of novel locomotor modes is often associated with morphological adaptations that help to meet those demands. In the goby lineage of fishes, most species are marine and use their fused pelvic fins to facilitate station holding in wave-swept environments. Read More

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Cutting Forces in Peripheral Up-Milling of Particleboard.

Materials (Basel) 2021 Apr 25;14(9). Epub 2021 Apr 25.

Department of Woodworking and Fundamentals of Machine Design, Faculty of Wood Technology, Poznan University of Life Sciences, ul. Wojska Polskiego 38-42, 60-637 Poznań, Poland.

An analysis of forces acting in the peripheral up-milling of particleboard is presented. First, a novel method of high-frequency piezoelectric force signal treatment is proposed and used to separate the original force signal from the vibrations of the previous cutting iteration. This allows for the analysis of single chip cutting force courses during industrial CNC (Computer Numerical Control) milling. Read More

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Tropomyosin 2.1 collaborates with fibronectin to promote TGF-β-induced contraction of human lung fibroblasts.

Respir Res 2021 Apr 28;22(1):129. Epub 2021 Apr 28.

Woolcock Emphysema Centre, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.

Many lung diseases are characterized by fibrosis, leading to impaired tissue patency and reduced lung function. Development of fibrotic tissue depends on two-way interaction between the cells and the extra-cellular matrix (ECM). Concentration-dependent increased stiffening of the ECM is sensed by the cells, which in turn increases intracellular contraction and pulling on the matrix causing matrix reorganization and further stiffening. Read More

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Chromosomal instability: Stretching the role of checkpoint silencing.

Curr Biol 2021 Apr;31(8):R386-R389

Chromosome Instability and Dynamics Group, i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; Cell Division Group, Experimental Biology Unit, Department of Biomedicine, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal. Electronic address:

Microtubule attachments to kinetochores cause their deformation - a murky phenomenon known as intra-kinetochore stretching. A new study proposes that intra-kinetochore stretching is independent of microtubule-pulling forces and mediates efficient spindle assembly checkpoint silencing to prevent chromosomal instability. Read More

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The coordination of spindle-positioning forces during the asymmetric division of the Caenorhabditis elegans zygote.

EMBO Rep 2021 05 26;22(5):e50770. Epub 2021 Apr 26.

CNRS, IGDR - UMR 6290, University of Rennes, Rennes, France.

In Caenorhabditis elegans zygote, astral microtubules generate forces essential to position the mitotic spindle, by pushing against and pulling from the cortex. Measuring microtubule dynamics there, we revealed the presence of two populations, corresponding to pulling and pushing events. It offers a unique opportunity to study, under physiological conditions, the variations of both spindle-positioning forces along space and time. Read More

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Asymmetry in histone rotation in forced unwrapping and force quench rewrapping in a nucleosome.

Nucleic Acids Res 2021 05;49(9):4907-4918

Department of Chemistry, The University of Texas, Austin, TX 78712, USA.

Single molecule pulling experiments have shown that DNA in the nucleosomes unwraps in two stages from the histone protein core (HPC). The first stage, attributed to the rupture of the outer DNA turn, occurs between 3 and 5 pNs, and is reversible. The inner DNA turn ruptures irreversibly at forces between 9 and 15 pNs (or higher) in the second stage. Read More

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Assembly and Activity of the WASH Molecular Machine: Distinctive Features at the Crossroads of the Actin and Microtubule Cytoskeletons.

Front Cell Dev Biol 2021 1;9:658865. Epub 2021 Apr 1.

Laboratoire de Biologie Structurale de la Cellule, CNRS, Ecole Polytechnique, IP Paris, Palaiseau, France.

The Arp2/3 complex generates branched actin networks at different locations of the cell. The WASH and WAVE Nucleation Promoting Factors (NPFs) activate the Arp2/3 complex at the surface of endosomes or at the cell cortex, respectively. In this review, we will discuss how these two NPFs are controlled within distinct, yet related, multiprotein complexes. Read More

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Estimating the Directional Flexibility of Proteins from Equilibrium Thermal Fluctuations.

J Chem Theory Comput 2021 May 5;17(5):3103-3118. Epub 2021 Apr 5.

Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, 400 005, India.

The directional flexibility of proteins is an equilibrium molecular property which is accessible to both experiment and computation. Single molecule force spectroscopy (SMFS) experiments report effective directional spring constants to describe the collective anisotropic response of a protein structure to mechanical pulling forces applied along selected axes. On the other hand, computational methods have thus far employed either indirect force based nonequilibrium simulations or coarse-grained elastic network models (ENM) to predict protein directional spring constants. Read More

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Influence of the Bar Position on Joint-Level Biomechanics During Isometric Pulling Exercises.

J Strength Cond Res 2021 Jun;35(6):1484-1490

Department of Physical Therapy, Program in Exercise Science, Marquette University, Milwaukee, Wisconsin.

Abstract: Ahn, N, Kim, H, Krzyszkowski, J, Roche, S, and Kipp, K. Influence of the bar position on joint-level biomechanics during isometric pulling exercises. J Strength Cond Res 35(6): 1484-1490, 2021-The purpose of this study was to investigate the influence of the bar position on ankle, knee, and hip net joint moments (NJMs), relative muscular effort (RME), and vertical ground reaction forces (GRFs) during isometric pulling exercises, such as the isometric midthigh pull. Read More

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Enantioselection and chiral sorting of single microspheres using optical pulling forces.

Opt Lett 2021 Apr;46(7):1640-1643

We put forward a novel, twofold scheme that enables, at the same time, all-optical enantioselection and sorting of single multipolar chiral microspheres based on optical pulling forces exerted by two non-collinear, non-structured, circularly polarized light sources. Our chiral resolution method can be externally controlled by varying the angle between their incident wavevectors, allowing for fine-tuning of the range of chiral indices for enantioselection. Enantioselectivity is achieved by choosing angles such that only particles with the same handedness of the light sources are pulled. Read More

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Seminars in cell and developmental biology: Anaphase A.

Semin Cell Dev Biol 2021 Mar 26. Epub 2021 Mar 26.

Dept. of Molecular, Cellular, and Developmental Biology University of Colorado, Boulder, CO 80309-0347, USA. Electronic address:

Anaphase A is the motion of recently separated chromosomes to the spindle pole they face. It is accompanied by the shortening of kinetochore-attached microtubules. The requisite tubulin depolymerization may occur at kinetochores, at poles, or both, depending on the species and/or the time in mitosis. Read More

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Self-organized patterning of cell morphology via mechanosensitive feedback.

Elife 2021 Mar 26;10. Epub 2021 Mar 26.

Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany.

Tissue organization is often characterized by specific patterns of cell morphology. How such patterns emerge in developing tissues is a fundamental open question. Here, we investigate the emergence of tissue-scale patterns of cell shape and mechanical tissue stress in the wing imaginal disc during larval development. Read More

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Highly-Parallel Microfluidics-Based Force Spectroscopy on Single Cytoskeletal Motors.

Small 2021 May 23;17(18):e2007388. Epub 2021 Mar 23.

B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01069, Dresden, Germany.

Cytoskeletal motors transform chemical energy into mechanical work to drive essential cellular functions. Optical trapping experiments have provided crucial insights into the operation of these molecular machines under load. However, the throughput of such force spectroscopy experiments is typically limited to one measurement at a time. Read More

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Atomic Force Microscopy: Single-Molecule Imaging and Force Spectroscopy in the Study of Flavoproteins Ligand Binding and Reaction Mechanisms.

Methods Mol Biol 2021 ;2280:157-178

Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.

Atomic force microscopy (AFM) is one of the most versatile tools currently used in nanoscience. AFM allows for performing nondestructive imaging of almost any sample in either air or liquid, regardless whether the specimen is insulating, conductive, transparent, or opaque. It also allows for measuring interaction forces between a sharp probe and a sample surface, therefore allowing to probe nanomechanical properties of the specimen by either applying a controlled force or pulling the sample. Read More

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Advanced in silico validation framework for three-dimensional traction force microscopy and application to an in vitro model of sprouting angiogenesis.

Acta Biomater 2021 05 15;126:326-338. Epub 2021 Mar 15.

Department of Mechanical Engineering, Biomechanics Section, KU Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium. Electronic address:

In the last decade, cellular forces in three-dimensional hydrogels that mimic the extracellular matrix have been calculated by means of Traction Force Microscopy (TFM). However, characterizing the accuracy limits of a traction recovery method is critical to avoid obscuring physiological information due to traction recovery errors. So far, 3D TFM algorithms have only been validated using simplified cell geometries, bypassing image processing steps or arbitrarily simulating focal adhesions. Read More

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Kinetochore stretching-mediated rapid silencing of the spindle-assembly checkpoint required for failsafe chromosome segregation.

Curr Biol 2021 Apr 1;31(8):1581-1591.e3. Epub 2021 Mar 1.

Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research, Tokyo, Japan. Electronic address:

The spindle-assembly checkpoint facilitates mitotic fidelity by delaying anaphase onset in response to microtubule vacancy at kinetochores. Following microtubule attachment, kinetochores receive microtubule-derived force, which causes kinetochores to undergo repetitive cycles of deformation; this phenomenon is referred to as kinetochore stretching. The nature of the forces and the relevance relating this deformation are not well understood. Read More

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Investigating the nature of active forces in tissues reveals how contractile cells can form extensile monolayers.

Nat Mater 2021 Feb 18. Epub 2021 Feb 18.

Université de Paris, CNRS, Institut Jacques Monod (IJM), Paris, France.

Actomyosin machinery endows cells with contractility at a single-cell level. However, within a monolayer, cells can be contractile or extensile based on the direction of pushing or pulling forces exerted by their neighbours or on the substrate. It has been shown that a monolayer of fibroblasts behaves as a contractile system while epithelial or neural progentior monolayers behave as an extensile system. Read More

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February 2021

Microtubule-independent movement of the fission yeast nucleus.

J Cell Sci 2021 Mar 26;134(6). Epub 2021 Mar 26.

Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK

Movement of the cell nucleus typically involves the cytoskeleton and either polymerization-based pushing forces or motor-based pulling forces. In the fission yeast , nuclear movement and positioning are thought to depend on microtubule polymerization-based pushing forces. Here, we describe a novel, microtubule-independent, form of nuclear movement in fission yeast. Read More

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An 18-Month Analysis of Bond Strength of Hot-Dip Galvanized Reinforcing Steel B500SP and S235JR+AR to Chloride Contaminated Concrete.

Materials (Basel) 2021 Feb 5;14(4). Epub 2021 Feb 5.

Faculty of Civil Engineering, Silesian University of Technology, 5 Akademicka, 44-100 Gliwice, Poland.

This article describes the comparative analysis of tests on bond strength of hot-dip galvanized and black steel to concrete with and without chlorides. The bond effect was evaluated with six research methods: strength, electrochemical (measurements of potential, EIS and LPR), optical, and 3D scanning. The tests were conducted within a long period of 18 months on 48 test elements reinforced with smooth rebars ϕ8 mm from steel grade S235JR+AR and ribbed rebars ϕ8 mm and ϕ16 mm from steel grade B500SP. Read More

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February 2021

Residue-by-residue analysis of cotranslational membrane protein integration in vivo.

Elife 2021 Feb 8;10. Epub 2021 Feb 8.

Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.

We follow the cotranslational biosynthesis of three multispanning inner membrane proteins in vivo using high-resolution force profile analysis. The force profiles show that the nascent chain is subjected to rapidly varying pulling forces during translation and reveal unexpected complexities in the membrane integration process. We find that an N-terminal cytoplasmic domain can fold in the ribosome exit tunnel before membrane integration starts, that charged residues and membrane-interacting segments such as re-entrant loops and surface helices flanking a transmembrane helix (TMH) can advance or delay membrane integration, and that point mutations in an upstream TMH can affect the pulling forces generated by downstream TMHs in a highly position-dependent manner, suggestive of residue-specific interactions between TMHs during the integration process. Read More

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February 2021

Collective dynein transport of the nucleus by pulling on astral microtubules during Saccharomyces cerevisiae mitosis.

Yeast 2021 Jun 27;38(6):352-366. Epub 2021 Feb 27.

Division of Biology, IISER Pune, Dr. Homi Bhabha Road, Pune, Maharashtra, 411008, India.

Positioning the nucleus at the bud neck during Saccharomyces cerevisiae mitosis involves pulling forces of cytoplasmic dynein localized in the daughter cell. Although genetic analysis has revealed a complex network positioning the nucleus, quantification of the forces acting on the nucleus and the number of dyneins driving the process has remained difficult. To better understand the collective forces involved in nuclear positioning, we compare a model of dyneins-driven microtubule (MT) pulling, MT pushing, and cytoplasmic drag to experiments. Read More

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Influence of external forces on actin-dependent T cell protrusions during immune synapse formation.

Biol Cell 2021 May 10;113(5):250-263. Epub 2021 Feb 10.

LadHyX, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, 91120, France.

Background Information: We have previously observed that in response to antigenic activation, T cells produce actin-rich protrusions that generate forces involved in T cell activation. These forces are influenced by the mechanical properties of antigen-presenting cells (APCs). However, how external forces, which can be produced by APCs, influence the dynamic of the actin protrusion remains unknown. Read More

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