Polarized basolateral cell motility underlies invagination and convergent extension of the ascidian notochord

Development ◽  
2002 ◽  
Vol 129 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Edwin M. Munro ◽  
Garrett M. Odell
Keyword(s):  
Cell Motility ◽  
Laser Scanning ◽  
Shape Change ◽  
Three Dimensional ◽  
Leading Edge ◽  
Time Lapse ◽  
Convergent Extension ◽  
Cellular Mechanisms ◽  
Cell Shape Change ◽  
Edge Extension

We use 3D time-lapse analysis of living embryos and laser scanning confocal reconstructions of fixed, staged, whole-mounted embryos to describe three-dimensional patterns of cell motility, cell shape change, cell rearrangement and tissue deformation that accompany formation of the ascidian notochord. We show that notochord formation involves two simultaneous processes occurring within an initially monolayer epithelial plate: The first is invagination of the notochord plate about the axial midline to form a solid cylindrical rod. The second is mediolaterally directed intercalation of cells within the plane of the epithelial plate, and then later about the circumference of the cylindrical rod, that accompanies its extension along the anterior/posterior (AP) axis. We provide evidence that these shape changes and rearrangements are driven by active extension of interior basolateral notochord cell edges directly across the faces of their adjacent notochord neighbors in a manner analogous to leading edge extension of lamellapodia by motile cells in culture. We show further that local edge extension is polarized with respect to both the AP axis of the embryo and the apicobasal axis of the notochord plate. Our observations suggest a novel view of how active basolateral motility could drive both invagination and convergent extension of a monolayer epithelium. They further reveal deep similarities between modes of notochord morphogenesis exhibited by ascidians and other chordate embryos, suggesting that cellular mechanisms of ascidian notochord formation may operate across the chordate phylum.

Morphogenetic pattern formation during ascidian notochord formation is regulative and highly robust

Development ◽  
2002 ◽  
Vol 129 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Edwin M. Munro ◽  
Garrett Odell
Keyword(s):  
Confocal Microscopy ◽  
Cell Shape ◽  
Shape Change ◽  
Time Lapse ◽  
Neural Plate ◽  
Convergent Extension ◽  
Complex Interplay ◽  
Cell Stage ◽  
Cell Shape Change ◽  
Global Patterns

The ascidian notochord forms through simultaneous invagination and convergent extension of a monolayer epithelial plate. Here we combine micromanipulation with time lapse and confocal microscopy to examine how notochord-intrinsic morphogenetic behaviors and interactions with surrounding tissues, determine these global patterns of movement. We show that notochord rudiments isolated at the 64-cell stage divide and become motile with normal timing; but, in the absence of interactions with non-notochordal tissues, they neither invaginate nor converge and extend. We find that notochord formation is robust in the sense that no particular neighboring tissue is required for notochord formation. Basal contact with either neural plate or anterior endoderm/lateral mesenchyme or posterior mesoderm are each alone sufficient to ensure that the notochord plate forms and extends a cylindrical rod. Surprisingly, the axis of convergent extension depends on the specific tissues that contact the notochord, as do other patterns of cell shape change, movement and tissue deformation that accompany notochord formation. We characterize one case in detail, namely, embryos lacking neural plates, in which a normal notochord forms but by an entirely different trajectory. Our results show ascidian notochord formation to be regulative in a fashion and to a degree never before appreciated. They suggest this regulative behavior depends on a complex interplay between morphogenetic tendencies intrinsic to the notochord plate and instructive and permissive interactions with surrounding tissues. We discuss mechanisms that could account for these data and what they imply about notochord morphogenesis and its evolution within the chordate phylum.

Toxicity Evaluation of Two Dental Composites: Three-Dimensional Confocal Laser Scanning Microscopy Time-Lapse Imaging of Cell Behavior

2013 ◽  
Vol 19 (3) ◽  
pp. 596-607 ◽  
Author(s):  
Ghania Nina Attik ◽  
Nelly Pradelle-Plasse ◽  
Doris Campos ◽  
Pierre Colon ◽  
Brigitte Grosgogeat
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Cell Metabolism ◽  
Three Dimensional ◽  
Time Lapse ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Dental Composites ◽  
Confocal Laser ◽  
Time Lapse Imaging

AbstractThe purpose of this study was to investigate thein vitrobiocompatibility of two dental composites (namely A and B) with similar chemical composition used for direct restoration using three-dimensional confocal laser scanning microscopy (CLSM) time-lapse imaging. Time-lapse imaging was performed on cultured human HGF-1 fibroblast-like cells after staining using Live/Dead®. Image analysis showed a higher mortality rate in the presence of composite A than composite B. The viability rate decreased in a time-dependent manner during the 5 h of exposure. Morphological alterations were associated with toxic effects; cells were enlarged and more rounded in the presence of composite A as shown by F-actin and cell nuclei staining. Resazurin assay was used to confirm the active potential of composites in cell metabolism; results showed severe cytotoxic effects in the presence of both no light-curing composites after 24 h of direct contact. However, extracts of polymerized composites induced a moderate decrease in cell metabolism after the same incubation period. Composite B was significantly better tolerated than composite A at all investigated end points and all time points. The finding confirmed that the used CLSM method was sufficiently sensitive to differentiate the biocompatibility behavior of two composites based on similar methacrylate monomers.

scholarly journals Cell migration through three-dimensional confining pores: speed accelerations by deformation and recoil of the nucleus

2019 ◽  
Vol 374 (1779) ◽  
pp. 20180225 ◽  
Author(s):  
Marina Krause ◽  
Feng Wei Yang ◽  
Mariska te Lindert ◽  
Philipp Isermann ◽  
Jan Schepens ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Migration ◽  
Shape Change ◽  
Three Dimensional ◽  
Time Lapse ◽  
Cell Cycle Phase ◽  
Cycle Phase ◽  
Change Analysis ◽  
Shape Adaptation ◽  
Interdisciplinary Approaches

Directional cell migration in dense three-dimensional (3D) environments critically depends upon shape adaptation and is impeded depending on the size and rigidity of the nucleus. Accordingly, the nucleus is primarily understood as a physical obstacle; however, its pro-migratory functions by stepwise deformation and reshaping remain unclear. Using atomic force spectroscopy, time-lapse fluorescence microscopy and shape change analysis tools, we determined the nuclear size, deformability, morphology and shape change of HT1080 fibrosarcoma cells expressing the Fucci cell cycle indicator or being pre-treated with chromatin-decondensating agent TSA. We show oscillating peak accelerations during migration through 3D collagen matrices and microdevices that occur during shape reversion of deformed nuclei (recoil), and increase with confinement. During G1 cell-cycle phase, nucleus stiffness was increased and yielded further increased speed fluctuations together with sustained cell migration rates in confinement when compared to interphase populations or to periods of intrinsic nuclear softening in the S/G2 cell-cycle phase. Likewise, nuclear softening by pharmacological chromatin decondensation or after lamin A/C depletion reduced peak oscillations in confinement. In conclusion, deformation and recoil of the stiff nucleus contributes to saltatory locomotion in dense tissues. This article is part of a discussion meeting issue ‘Forces in cancer: interdisciplinary approaches in tumour mechanobiology’.

Microtubules and mitotic cycle phase modulate spatiotemporal distributions of F-actin and myosin II in Drosophila syncytial blastoderm embryos

Development ◽  
2000 ◽  
Vol 127 (9) ◽  
pp. 1767-1787 ◽  
Author(s):  
V.E. Foe ◽  
C.M. Field ◽  
G.M. Odell
Keyword(s):  
Laser Scanning ◽  
Myosin Ii ◽  
Three Dimensional ◽  
Time Lapse ◽  
Laser Scanning Confocal Microscopy ◽  
Cycle Phase ◽  
Filamentous Actin ◽  
Mitotic Apparatus ◽  
Scanning Confocal Microscopy ◽  
Drug Treatments

We studied cyclic reorganizations of filamentous actin, myosin II and microtubules in syncytial Drosophila blastoderms using drug treatments, time-lapse movies and laser scanning confocal microscopy of fixed stained embryos (including multiprobe three-dimensional reconstructions). Our observations imply interactions between microtubules and the actomyosin cytoskeleton. They provide evidence that filamentous actin and cytoplasmic myosin II are transported along microtubules towards microtubule plus ends, with actin and myosin exhibiting different affinities for the cell's cortex. Our studies further reveal that cell cycle phase modulates the amounts of both polymerized actin and myosin II associated with the cortex. We analogize pseudocleavage furrow formation in the Drosophila blastoderm with how the mitotic apparatus positions the cleavage furrow for standard cytokinesis, and relate our findings to polar relaxation/global contraction mechanisms for furrow formation.

Camera tracking and qualitative airflow assessment of a two-turn erect spin

2012 ◽  
Vol 116 (1179) ◽  
pp. 541-562
Author(s):  
R. I. Hoff ◽  
G. B. Gratton
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Leading Edge ◽  
Flow Visualisation ◽  
Camera Tracking ◽  
Spin Motion ◽  
Large Vortex ◽  
Quality Video ◽  
Edge Vortex ◽  
High Quality Video

Abstract Motion and airflow during a two-turn erect spin of an aerobatic light aeroplane have been analysed. An alternative method, based upon camera tracking, has been used to capture the spin motion. A CAD model of the Slingsby Firefly was created using laser scanning. Formation flights with a helicopter have been flown and high-quality video and still imagery obtained. Camera tracking has produced data and unique illustrations of the spinning Slingsby. To further investigate the aerodynamic flow of a spinning aeroplane, full-scale, flow visualisation flights have been flown using wool tufts on wing, fuselage and empennage. Tufts indicate that a large vortex forms on the outside wing. The spanwise motion of this vortex has been studied and related to the spin motion. Furthermore, tufts on the horizontal tail indicate the presence of a leading edge vortex with the flow mainly in a spanwise outwards direction. The effects observed are clearly three dimensional and time dependent. Finally, it is discussed how this new knowledge does not correspond with the spin theories of the past.

scholarly journals A contractile actomyosin network linked to adherens junctions by Canoe/afadin helps drive convergent extension

2011 ◽  
Vol 22 (14) ◽  
pp. 2491-2508 ◽  
Author(s):  
Jessica K. Sawyer ◽  
Wangsun Choi ◽  
Kuo-Chen Jung ◽  
Li He ◽  
Nathan J. Harris ◽  
...  
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Adherens Junction ◽  
Tissue Level ◽  
The Body ◽  
Convergent Extension ◽  
Planar Polarity ◽  
Cell Shape Change ◽  
Apical Polarity ◽  
Polarity Proteins

Integrating individual cell movements to create tissue-level shape change is essential to building an animal. We explored mechanisms of adherens junction (AJ):cytoskeleton linkage and roles of the linkage regulator Canoe/afadin during Drosophila germband extension (GBE), a convergent-extension process elongating the body axis. We found surprising parallels between GBE and a quite different morphogenetic movement, mesoderm apical constriction. Germband cells have an apical actomyosin network undergoing cyclical contractions. These coincide with a novel cell shape change—cell extension along the anterior–posterior (AP) axis. In Canoe's absence, GBE is disrupted. The apical actomyosin network detaches from AJs at AP cell borders, reducing coordination of actomyosin contractility and cell shape change. Normal GBE requires planar polarization of AJs and the cytoskeleton. Canoe loss subtly enhances AJ planar polarity and dramatically increases planar polarity of the apical polarity proteins Bazooka/Par3 and atypical protein kinase C. Changes in Bazooka localization parallel retraction of the actomyosin network. Globally reducing AJ function does not mimic Canoe loss, but many effects are replicated by global actin disruption. Strong dose-sensitive genetic interactions between canoe and bazooka are consistent with them affecting a common process. We propose a model in which an actomyosin network linked at AP AJs by Canoe and coupled to apical polarity proteins regulates convergent extension.

scholarly journals Adaptive prospective optical gating enables day-long 3D time-lapse imaging of the beating embryonic zebrafish heart

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jonathan M. Taylor ◽  
Carl J. Nelson ◽  
Finnius A. Bruton ◽  
Aryan Kaveh ◽  
Charlotte Buckley ◽  
...  
Keyword(s):  
Time Course ◽  
Cardiac Development ◽  
Three Dimensional ◽  
Time Lapse ◽  
Beating Heart ◽  
Cellular Mechanisms ◽  
Phase Lock ◽  
Optical Gating ◽  
Time Lapse Imaging ◽  
Zebrafish Heart

AbstractThree-dimensional fluorescence time-lapse imaging of the beating heart is extremely challenging, due to the heart’s constant motion and a need to avoid pharmacological or phototoxic damage. Although real-time triggered imaging can computationally “freeze” the heart for 3D imaging, no previous algorithm has been able to maintain phase-lock across developmental timescales. We report a new algorithm capable of maintaining day-long phase-lock, permitting routine acquisition of synchronised 3D + time video time-lapse datasets of the beating zebrafish heart. This approach has enabled us for the first time to directly observe detailed developmental and cellular processes in the beating heart, revealing the dynamics of the immune response to injury and witnessing intriguing proliferative events that challenge the established literature on cardiac trabeculation. Our approach opens up exciting new opportunities for direct time-lapse imaging studies over a 24-hour time course, to understand the cellular mechanisms underlying cardiac development, repair and regeneration.

A Dynamic Spar Numerical Model for Passive Shape Change

2015 ◽  
Author(s):  
Joseph Calogero ◽  
Mary Frecker ◽  
Zohaib Hasnain ◽  
James E. Hubbard
Keyword(s):  
Numerical Model ◽  
Performance Metrics ◽  
Shape Change ◽  
Damping Ratio ◽  
Three Dimensional ◽  
Leading Edge ◽  
Spatial Optimization ◽  
Starting Point ◽  
Compliant Joint ◽  
Number Of Cycles

A three-dimensional constraint-driven numerical dynamic model of a flapping wing structure called the Dynamic Spar Numerical Model (DSNM) is introduced and implemented. The model currently includes a leading edge spar and a diagonal spar, attached to a body by revolute and spherical joints, respectively. The spars consist of a user-specified number of rigid links connected by compliant joints (CJs): spherical joints with distributed masses and three axis nonlinear torsional spring-dampers. The goal of this model is to quickly simulate mechanisms in a test platform to see how their CJ design properties and spatial distribution affect passive shape change and physical performance metrics. The results of this model can be used as a starting point for further refinement in compliant joint design for passive shape change. Previous research leading to and assumptions made for modeling CJ are presented. The constraints are established, followed by the formulation of a state model used in conjunction with a forward time integrator, and finally several example runs. Modeling the CJs as linear springs produces a nearly symmetric rotation angles through the flapping cycle, while bi-linear springs show the wing is able to flex more during upstroke than downstroke. Increasing damping ratio reduces high frequency oscillations during the flapping cycle and the number of cycles required to reach steady state. Coupling the spring stiffnesses allows an angle about one axis to induce an angle about another axis, where the magnitude is proportional to the coupling term. Modeling both the leading edge and diagonal spars show that the diagonal spar changes the kinematics of the leading edge spar verses only considering the leading edge spar, causing much larger axial rotations in the leading edge spar. The kinematics are very sensitive to CJ location, where moving the CJ toward the wing root causes a stronger response, and adding multiple CJs on the leading edge spar with a CJ on the diagonal spar allow the wing to deform with larger magnitude in all directions. Future work includes implementing a performance metric, experimental verification, applying loads to represent ambient and flight conditions, and using the model as an optimization tool for parameter and spatial optimization.

scholarly journals Vortex interaction on a LEX configuration

2021 ◽  
Author(s):  
Moo-Ting Chou ◽  
Jiun-Jih Miau ◽  
Li-Yu Chen
Keyword(s):  
Reynolds Number ◽  
Water Channel ◽  
Three Dimensional ◽  
Leading Edge ◽  
Quantitative Information ◽  
Extension Model ◽  
Image Velocimetry ◽  
Visualization Experiments ◽  
Low Speed Wind Tunnel ◽  
Edge Extension

AbstractFlow visualization experiments were conducted in a water channel and a low-speed wind tunnel at Reynolds number of 1.54 $$\times$$ × 104 to 1.2 $$\times$$ × 105 for a leading-edge extension model, which is referred to as a NASA TP-1803 model in this study. In addition, particle image velocimetry velocity measurements were taken in the water channel to obtain the quantitative information about the three-dimensional velocity field over the strake and wing surfaces. The results obtained at low, medium and high angles of attacks represent three distinct cases of interaction between the strake and wing vortices. Namely, at α = 5o and 10° the strake and wing vortices were developed over the wing surface without significant interaction noticed; at α = 20°, the strake vortex strongly interacted with the wing vortex in an intertwining manner, which was sensitive to Reynolds number; at α = 30°, the breakdown of the strake vortex took place close to the junction of the strake and the wing; thus, the interaction of the strake and the wing vortices appeared to be less significant than the case of α = 20°. Graphic abstract

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