Die GFP-β-Aktin Plasmid wurde freundlicherweise von Dr. Wayne Orr, LSUHSC-S Department of Pathology Verfügung gestellt und wurde im Labor von Dr. Becky Worthylake, LSUHSC-NO Department of Pharmacology verstärkt. Diese Arbeit wurde durch Mittel der National Institutes of Health (P20 RR-018766) und der American Heart Association (05835386N) unterstützt.

<ol>
	<li>Spindler, V., Schlegel, N., Waschke, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+GTPases+in+control+of+microvascular+permeability.">Role of GTPases in control of microvascular permeability.</a> Cardiovasc. Res. 87, 243-253 (2010).</li><li>Wojciak-Stothard, B., Ridley, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rho+GTPases+and+the+regulation+of+endothelial+permeability.">Rho GTPases and the regulation of endothelial permeability.</a> Vascul. Pharmacol. 39, 187-199 (2002).</li><li>Yuan, S. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signal+transduction+pathways+in+enhanced+microvascular+permeability.">Signal transduction pathways in enhanced microvascular permeability.</a> Microcirculation. 7, 395-403 (2000).</li><li>Birukov, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+GTPases+in+mechanosensitive+regulation+of+endothelial+barrier.">Small GTPases in mechanosensitive regulation of endothelial barrier.</a> Microvasc. Res. 77, 46-52 (2009).</li><li>Duran, W. N., Sanchez, F. A., Breslin, J. W., Tuma, R. F., Duran, W. N., Ley, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microcirculatory+Exchange+Function.">Microcirculatory Exchange Function.</a> Handbook of Physiology: Microcirculation. , 81-124 (2008).</li><li>Hu, Y. L., Chien, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+motion+of+paxillin+on+actin+filaments+in+living+endothelial+cells.">Dynamic motion of paxillin on actin filaments in living endothelial cells.</a> Biochem. Biophys. Res. Commun. 357, 871-876 (2007).</li><li>Borm, B., Requardt, R. P., Herzog, V., Kirfel, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Membrane+ruffles+in+cell+migration:+indicators+of+inefficient+lamellipodia+adhesion+and+compartments+of+actin+filament+reorganization.">Membrane ruffles in cell migration: indicators of inefficient lamellipodia adhesion and compartments of actin filament reorganization.</a> Exp. Cell. Res. 302, 83-95 (2005).</li><li>Hotulainen, P., Lappalainen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+fibers+are+generated+by+two+distinct+actin+assembly+mechanisms+in+motile+cells.">Stress fibers are generated by two distinct actin assembly mechanisms in motile cells.</a> J. Cell. Biol. 173, 383-394 (2006).</li><li>Pellegrin, S., Mellor, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Actin+stress+fibres.">Actin stress fibres.</a> J. Cell. Sci. 120, 3491-3499 (2007).</li><li>Ballestrem, C., Wehrle-Haller, B., Imhof, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Actin+dynamics+in+living+mammalian+cells.">Actin dynamics in living mammalian cells.</a> J. Cell. Sci. 111, 1649-1658 (1998).</li><li>Helmke, B. P., Rosen, A. B., Davies, P. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+mechanical+strain+of+an+endogenous+cytoskeletal+network+in+living+endothelial+cells.">Mapping mechanical strain of an endogenous cytoskeletal network in living endothelial cells.</a> Biophys. J. 84, 2691-2699 (2003).</li><li>Birukova, A. A., Smurova, K., Birukov, K. G., Kaibuchi, K., Garcia, J. G., Verin, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+Rho+GTPases+in+thrombin-induced+lung+vascular+endothelial+cells+barrier+dysfunction.">Role of Rho GTPases in thrombin-induced lung vascular endothelial cells barrier dysfunction.</a> Microvasc. Res. 67, 64-77 (2004).</li><li>van Nieuw Amerongen, G. P., van Delft, S., Vermeer, M. A., Collard, J. G., van Hinsbergh, V. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+of+RhoA+by+thrombin+in+endothelial+hyperpermeability:+role+of+Rho+kinase+and+protein+tyrosine+kinases.">Activation of RhoA by thrombin in endothelial hyperpermeability: role of Rho kinase and protein tyrosine kinases.</a> Circ. Res. 87, 335-340 (2000).</li><li>Moy, A. B., Blackwell, K., Kamath, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+effects+of+histamine+and+thrombin+on+endothelial+barrier+function+through+actin-myosin+tension.">Differential effects of histamine and thrombin on endothelial barrier function through actin-myosin tension.</a> Am J Physiol Heart Circ Physiol. 282, H21-H29 (2002).</li><li>Wittman, T., Littlefield, R., Waterman-Storer, C., Goldman, R. D., Spector, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+speckle+microscopy+of+cytoskeletal+dynamics+in+living+cells.">Fluorescent speckle microscopy of cytoskeletal dynamics in living cells.</a> Live Cell Imaging: A Laboratory Manual. , 184-204 (2005).</li><li>Rabut, G., Ellenberg, J., Goldman, R. D., Spector, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photobleaching+techniques+to+study+mobility+and+molecular+dynamics+of+proteins+in+live+cells:+FRAP,+iFRAP,+and+FLIP.">Photobleaching techniques to study mobility and molecular dynamics of proteins in live cells: FRAP, iFRAP, and FLIP.</a> Live Cell Imaging: A Laboratory Manual. , 101-126 (2005).</li></ol>

Keine Interessenskonflikte erklärt.

Die Bildgebung von GFP-Aktin in lebenden Endothelzellen ermöglicht eine detaillierte Analyse der Dynamik des Aktin-Zytoskeletts in Reaktion auf entzündliche Reize. Diese Methode kann auch nützlich sein, um auf frühere Ergebnisse zeigen Umbau des Zytoskeletts in Reaktion auf physikalische Kräfte wie Schubspannung 11 Build. Darüber hinaus ermöglicht diese Methode eine detaillierte Bewertung des Beitrags von Aktin-Zytoskelett Dynamik zu verschiedenen Endothelzellen, einschließlich der Migration, der Mitose, die Bildung von interzellulären Verbindungen und junctional Reifung und Pflege der Barrierefunktion. In den Daten zeigt, kann das Verhalten des endothelialen Aktin-Zytoskeletts vor und nach der Behandlung mit Thrombin beobachtet werden. Lokale Lamellipodien alle an den Rändern von Endothelzellen beobachtet Umform-und Rückschritte im Laufe der Zeit in beiden nonconfluent und konfluierende Zellrasen. Die Behandlung mit Thrombin kurz unterbrochen Lamellipodien FormATION und Umsatz. Thrombin verursachte auch die Zellen mit einem leicht rückläufigen, in Übereinstimmung mit früheren Berichten, dass Thrombin Aktin Stress Faserbildung und erhöhte zentripetalen Zug der Entwicklung in Endothelzellen 12-14 Ursachen. Jedoch von Live Cell Imaging Studien wie diese, kann der Ursprung des Stress-Fasern nun ermittelt werden. In HUVEC, die meisten Stress-Fasern an der Zellperipherie stammen und ähneln quer arc Fasern in wandernden Zellen 8, 9. Eine weitere Stärke dieser Methode gegenüber der Verwendung fixierten Zellen ist, dass die Zahl der Stress-Fasern in einzelnen Zellen können vor und nach der Thrombin-Behandlung quantifiziert werden, sodass selection bias zwischen experimentellen Gruppen. Mit diesem Protokoll bewerten wir dynamische Bewegung der Zelle Rand und Aktin Stress-Fasern. Um Aktin Monomer Dynamik in Endothelzellen, fortgeschrittene Techniken wie die Fluoreszenz-Recovery verstehen nach Ausbleichen (FRAP) oder Fluoreszenz-Speckle-microscopy (FSM) können 15 aufgebracht werden, 16. Darüber hinaus, weil mikrovaskulären Endothelzellen darstellen können ein besseres Modell der mikrovaskulären Barrierefunktion, die Optimierung der Transfektion Protokolle effektiv auszudrücken GFP-Aktin in mikrovaskulären Endothelzellen stellt einen logischen zukünftige Richtung. Zusammenfassend stellt Imaging an lebenden Endothelzellen exprimieren GFP-Aktin ein mächtiges Werkzeug, um festzustellen, wie die Endothelzellen Aktin-Zytoskeletts, um verschiedene Arten von Stimuli reagiert. Studien mit eng konfluente Endothelzellen Monoschichten wird helfen, die Rolle des dynamischen Strukturen wie Aktin-reichen Lamellipodien und quer arc Stress Fasern in endothelialen Barrierefunktion. Darüber hinaus werden Live Cell Imaging von endothelialen Zellen, die GFP-Aktin oder anderen Fusionsproteine, die Visualisierung von anderen subzellulären Strukturen ermöglichen eine detaillierte raumzeitliche Informationen, die zur Signalisierung und strukturellen Mechanismen zu verstehen, dass determine Barriere Integrität.

<table border="1"><tbody><tr><td colspan="4"> 1. Ringer 5x Lager </td></tr><tr><td> Chemikalie </td><td> Firma </td><td> Katalog-Nummer </td><td> Höhe </td></tr><tr><td> Kochsalz </td><td> EMD </td><td> SX0420-3 </td><td> 35 g </td></tr><tr><td> Kaliumchlorid </td><td> JT Baker </td><td> 3040 </td><td> 1,75 g </td></tr><tr><td> Calcium Chloride </td><td> Sigma </td><td> C-3881 </td><td> 1,47 g </td></tr><tr><td> Magnesium Sulfate </td><td> Sigma </td><td> M-9397 </td><td> 1,44 g </td></tr><tr><td> Steriles gefiltertes Wasser </td><td> N / A </td><td> N / A </td><td> Bring to 1 L </td></tr><tr><td colspan="4"> Sterile Filter in autoklaviert Flaschen und speichert bei 4 ° C </td></tr><tr><td colspan="4"></td></tr><tr><td colspan="4"> 2. MOPS-Puffer </td></tr><tr><td> Chemikalie </td><td>Firma </td><td> Katalog-Nummer </td><td> Höhe </td></tr><tr><td> MOPS </td><td> Sigma </td><td> M3183 </td><td> 125,6 g </td></tr><tr><td> Steriles gefiltertes Wasser </td><td> N / A </td><td> N / A </td><td> Bring to 1 L </td></tr><tr><td colspan="4"> Sterile Filter in autoklaviert Flaschen und speichert bei 4 ° C </td></tr><tr><td colspan="4"></td></tr><tr><td colspan="4"> 3. Albumin physiologischer Kochsalzlösung (APSS) </td></tr><tr><td> Chemikalie </td><td> Firma </td><td> Katalog-Nummer </td><td> Höhe </td></tr><tr><td> Ringer Lager (5x) </td><td> N / A </td><td> N / A </td><td> 200 ml </td></tr><tr><td> MOPS-Puffer </td><td> N / A </td><td> N / A </td><td> 5 mL </td></tr><tr><td> Sodium Phosphate </td><td> Sigma </td><td> S-9638 </td><td> 0,168 g </td></tr><tr><td> Natriumpyruvat &lt;/ Td&gt; <td> Sigma </td><td> P5280 </td><td> 0,22 g </td></tr><tr><td> EDTA-Natriumsalz </td><td> Sigma </td><td> ED2SS </td><td> 0,0074 g </td></tr><tr><td> Glucose </td><td> Sigma </td><td> G7528 </td><td> 0,901 g </td></tr><tr><td> Albumin, Bovine </td><td> USB </td><td> 10856 </td><td> 10 g </td></tr><tr><td> Steriles gefiltertes Wasser </td><td> N / A </td><td> N / A </td><td> Bring to 1 L </td></tr><tr><td colspan="4"> Der pH-Wert auf 7,4 bei 37 ° C, dann Sterilfilter in autoklaviert Flaschen und lagern bei 4 ° C. </td></tr><tr><td colspan="4"></td></tr><tr><td colspan="4"> 4. 0,9% Saline </td></tr><tr><td> Chemikalie </td><td> Firma </td><td> Katalog-Nummer </td><td> Höhe </td></tr><tr><td> Kochsalz </td><td> EMD </td><td> SX0420-3 </td><td> 9 g </td></tr><tr><td> Steriles gefiltertes Wasser </td><td> N / A </td><td> N / A </td><td> Bring to 1 L </td></tr><tr><td colspan="4"> Sterile Filter in autoklaviert Flaschen und speichert bei 4 ° C </td></tr><tr><td colspan="4"></td></tr><tr><td colspan="4"> 5. 1,5% Gelatine-Lösung </td></tr><tr><td> Gelatine aus Schweinehaut </td><td> Sigma </td><td> G2500 </td><td> 15 g </td></tr><tr><td> 0,9% Saline </td><td> N / A </td><td> N / A </td><td> Bring to 1 L </td></tr><tr><td colspan="4"> Wärmen Sie die Lösung auf 37 ° C zu lösen Gelatine ausreichend. Während noch warm, Sterilfilter in autoklaviert Flaschen und lagern bei 4 ° C </td></tr></tbody></table>

study of the actin cytoskeleton in live endothelial cells expressing gfp-actin

Die mikrovaskuläre Endothel spielt eine wichtige Rolle als eine selektiv durchlässige Barriere gegen Flüssigkeiten und gelöste Stoffe. Der Klebstoff Übergänge zwischen Endothelzellen regulieren Permeabilität des Endothels, und viele Studien haben den wichtigen Beitrag des Aktin-Zytoskeletts auf die Bestimmung junctional Integrität 1-5 angegeben. Ein kortikalen Aktin-Gürtel wird angenommen, dass für die Aufrechterhaltung stabiler Verbindungen 1, 2, 4, 5 wichtig. Im Gegensatz dazu sind Aktin-Stress-Fasern gedacht, zentripetalen Spannungen innerhalb Endothelzellen, die Kreuzungen 2-5 schwächt generieren. Ein großer Teil dieser Theorie hat sich auf Studien, in denen Endothelzellen mit Entzündungsmediatoren bekannt endotheliale Permeabilität zu erhöhen behandelt werden, und dann Fixierung der Zellen und Kennzeichnung F-Aktin für die mikroskopische Beobachtung basiert. Allerdings liefern diese Studien ein sehr begrenztes Verständnis von der Rolle des Aktin-Zytoskeletts, weil Bilder von fixierten Zellen nur Momentaufnahmen liefern inZeit ohne Informationen über die Dynamik des Aktin-Strukturen 5. Live-Cell-Imaging ermöglicht Einbindung der dynamischen Natur des Aktin-Zytoskeletts in den Studien über die Mechanismen der Bestimmung endothelialen Barriere Integrität. Ein großer Vorteil dieser Methode ist, dass die Auswirkungen der verschiedenen entzündlichen Stimuli auf Aktin-Strukturen in Endothelzellen in die gleiche Gruppe von lebenden Zellen vor und nach der Behandlung beurteilt werden kann, Beseitigung möglicher Bias, die auftreten, wenn die Beobachtung fixierten Proben können. HUVEC-Zellen (HUVEC) mit einem GFP-β-Aktin transfiziert gewachsen und bis zur Konfluenz auf Deckgläschen. Zeitraffer-Bilder von GFP-Aktin in konfluenten HUVEC werden vor und nach der Zugabe von Entzündungsmediatoren, die zeitabhängige Veränderungen in endothelialen Barriere Integrität entlocken eingefangen. Diese Studien ermöglichen die visuelle Beobachtung der Flüssigkeit Folge von Veränderungen in der Aktin-Zytoskeletts, die Endothelien beitragenl Schrankenstörung und Restaurierung. Unsere Ergebnisse zeigen übereinstimmend, lokale, Aktin-reichen Lamellipodien Bildung und Umsatz in Endothelzellen. Die Bildung und Bewegung von Aktin-Stress-Fasern können auch beobachtet werden. Eine Analyse der Häufigkeit der Bildung und des Umsatzes des lokalen Lamellipodien, vor und nach der Behandlung mit entzündlichen Reizen kann durch Kymographion Analysen dokumentiert werden. Diese Studien liefern wichtige Informationen über die dynamische Natur des Aktin-Zytoskeletts in Endothelzellen, die verwendet werden, um bisher nicht identifizierten molekularen Mechanismen wichtig für die Aufrechterhaltung der endothelialen Barriere Integrität entdecken können.

Watch this Scientific Journal Video about Study of the Actin Cytoskeleton in Live Endothelial Cells Expressing GFP-Actin at JoVE.com

Study of the Actin Cytoskeleton in Live Endothelial Cells Expressing GFP-Actin

Mikroskopische Aufnahmen von Live-Endothelzellen exprimieren GFP-Aktin ermöglicht die Charakterisierung der dynamischen Veränderungen in Zytoskelettstrukturen. Im Gegensatz zu Techniken, die fixierten Proben verwenden, bietet diese Methode eine detaillierte Bewertung der zeitlichen Veränderungen in der Aktin-Zytoskelett in den gleichen Zellen vor, während und nach verschiedenen physikalischen, pharmakologischen oder entzündliche Reize.

Studie des Aktin-Zytoskeletts in Live Endothelial Cells, die GFP-Aktin

The microvascular endothelium plays an important role as a selectively permeable barrier to fluids and solutes. The adhesive junctions between endothelial ...

study-actin-cytoskeleton-live-endothelial-cells-expressing-gfp

Research

Education

JoVE Journal

JoVE Core

Cell Biology

Biology

Unit 1

The Cytoskeleton I: Actin and Microfilaments

SCIENTISTS IN ACTION

27.0K Aufrufe.  Louisiana State University Health Sciences Center. Mikroskopische Aufnahmen von Live-Endothelzellen exprimieren GFP-Aktin ermöglicht die Charakterisierung der dynamischen Veränderungen in Zytoskelettstrukturen. Im Gegensatz zu Techniken, die fixierten Proben verwenden, bietet diese Methode eine detaillierte Bewertung der zeitlichen Veränderungen in der Aktin-Zytoskelett in den gleichen Zellen vor, während und nach verschiedenen physikalischen, pharmakologischen oder entzündliche Reize.

Serie: Study of the Actin Cytoskeleton in Live Endothelial Cells Expressing GFP-Actin

Testing Visual Sensitivity to the Speed and Direction of Motion in Lizards

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of the visual system provide more empirical evidence for functional applications. Investigation into the sensory system provides information about the sensory capacity, learning and memory ability, and establishes known baseline behaviour in which to gauge deviations (Burghardt, 1977). However, unlike mammalian or avian systems, testing for learning and memory in a reptile species is difficult. Furthermore, using an operant paradigm as a psychophysical measure of sensory ability is likewise as difficult. Historically, reptilian species have responded poorly to conditioning trials because of issues related to motivation, physiology, metabolism, and basic biological characteristics. Here, I demonstrate an operant paradigm used a novel model lizard species, the Jacky dragon (Amphibolurus muricatus) and describe how to test peripheral sensitivity to salient speed and motion characteristics. This method uses an innovative approach to assessing learning and sensory capacity in lizards. I employ the use of random-dot kinematograms (RDKs) to measure sensitivity to speed, and manipulate the level of signal strength by changing the proportion of dots moving in a coherent direction. RDKs do not represent a biologically meaningful stimulus, engages the visual system, and is a classic psychophysical tool used to measure sensitivity in humans and other animals. Here, RDKs are displayed to lizards using three video playback systems. Lizards are to select the direction (left or right) in which they perceive dots to be moving. Selection of the appropriate direction is reinforced by biologically important prey stimuli, simulated by computer-animated invertebrates.

Testing visual sensitivity in lizards using an operant conditioning paradigm that employs video playback of random-dot kinematograms and computer-generated invertebrates.

Testen visueller Sensibilität für die Geschwindigkeit und Richtung der Bewegung in Lizards

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of ...

Forschung

Biologie

Computer-Generated Animal Model Stimuli

Communication between animals is diverse and complex. Animals may communicate using auditory, seismic, chemosensory, electrical, or visual signals. In particular, understanding the constraints on visual signal design for communication has been of great interest. Traditional methods for investigating animal interactions have used basic observational techniques, staged encounters, or physical manipulation of morphology. Less intrusive methods have tried to simulate conspecifics using crude playback tools, such as mirrors, still images, or models. As technology has become more advanced, video playback has emerged as another tool in which to examine visual communication (Rosenthal, 2000). However, to move one step further, the application of computer-animation now allows researchers to specifically isolate critical components necessary to elicit social responses from conspecifics, and manipulate these features to control interactions. Here, I provide detail on how to create an animation using the Jacky dragon as a model, but this process may be adaptable for other species. In building the animation, I elected to use Lightwave  3D to alter object morphology, add texture, install bones, and provide comparable weight shading that prevents exaggerated movement. The animation is then matched to select motor patterns to replicate critical movement features. Finally, the sequence must rendered into an individual clip for presentation. Although there are other adaptable techniques, this particular method had been demonstrated to be effective in eliciting both conspicuous and social responses in staged interactions.

Computer-generated stimuli using the Jacky dragon as a model.

Computer-Generated-Tiermodell Stimuli

Communication between animals is diverse and complex. Animals may communicate using auditory, seismic, chemosensory, electrical, or visual signals. In ...

Actin Co-Sedimentation Assay; for the Analysis of Protein Binding to F-Actin

The actin cytoskeleton within the cell is a network of actin filaments that allows the movement of cells and cellular processes, and that generates tension and helps maintains cellular shape.  Although the actin cytoskeleton is a rigid structure, it is a dynamic structure that is constantly remodeling.  A number of proteins can bind to the actin cytoskeleton.  The binding of a particular protein to F-actin is often desired to support cell biological observations or to further understand dynamic processes due to remodeling of the actin cytoskeleton. The actin co-sedimentation assay is an in vitro assay routinely used to analyze the binding of specific proteins or protein domains with F-actin.  The basic principles of the assay involve an incubation of the protein of interest (full length or domain of) with F-actin, ultracentrifugation step to pellet F-actin and analysis of the protein co-sedimenting with F-actin.  Actin co-sedimentation assays can be designed accordingly to measure actin binding affinities and in competition assays.

Proteins bind to filamentous actin (F-actin) through distinct actin binding modules. In this video we demonstrate the procedure of actin co-sedimentation, which is an in vitro assay routinely used to analyze proteins or specific domains that bind F-actin.

Aktin Co-Sedimentation Assay; für die Analyse von Protein-Bindung an F-Aktin

The actin cytoskeleton within the cell is a network of actin filaments that allows the movement of cells and cellular processes, and that generates ...

Live Cell Imaging of F-actin Dynamics via Fluorescent Speckle Microscopy (FSM)

In this protocol we describe the use of Fluorescent Speckle Microscopy (FSM) to capture high-resolution images of actin dynamics in PtK1 cells. A unique advantage of FSM is its ability to capture the movement and turnover kinetics (assembly/disassembly) of the F-actin network within living cells. This technique is particularly useful in deriving quantitative measurements of F-actin dynamics when paired with computer vision software (qFSM).  We describe  the selection, microinjection and visualization of fluorescent actin probes in living cells. Importantly, similar procedures are applicable to visualizing other macomolecular assemblies. FSM has been demonstrated for microtubules, intermediate filaments, and adhesion complexes.  

Live Cell Imaging of F-actin Dynamics via Fluorescent Speckle Microscopy FSM

Selection, microinjection, and imaging of fluorescently-labeled F-actin via fluorescent speckle microscopy (FSM).

Live Cell Imaging von F-Aktin Dynamics über Fluorescent Speckle Microscopy (FSM)

In this protocol we describe the use of Fluorescent Speckle Microscopy (FSM) to capture high-resolution images of actin dynamics in PtK1 cells. A unique ...

Live Imaging of Cell Motility and Actin Cytoskeleton of Individual Neurons and Neural Crest Cells in Zebrafish Embryos

The zebrafish is an ideal model for imaging cell behaviors during development in vivo. Zebrafish embryos are externally fertilized and thus easily accessible at all stages of development. Moreover, their optical clarity allows high resolution imaging of cell and molecular dynamics in the natural environment of the intact embryo. We are using a live imaging approach to analyze cell behaviors during neural crest cell migration and the outgrowth and guidance of neuronal axons.
Live imaging is particularly useful for understanding mechanisms that regulate cell motility processes. To visualize details of cell motility, such as protrusive activity and molecular dynamics, it is advantageous to label individual cells. In zebrafish, plasmid DNA injection yields a transient mosaic expression pattern and offers distinct benefits over other cell labeling methods. For example, transgenic lines often label entire cell populations and thus may obscure visualization of the fine protrusions (or changes in molecular distribution) in a single cell. In addition, injection of DNA at the one-cell stage is less invasive and more precise than dye injections at later stages.
Here we describe a method for labeling individual developing neurons or neural crest cells and imaging their behavior in vivo. We inject plasmid DNA into 1-cell stage embryos, which results in mosaic transgene expression. The vectors contain cell-specific promoters that drive expression of a gene of interest in a subset of sensory neurons or neural crest cells. We provide examples of cells labeled with membrane targeted GFP or with a biosensor probe that allows visualization of F-actin in living cells1.
Erica Andersen, Namrata Asuri, and Matthew Clay contributed equally to this work.

This protocol describes imaging of individual neurons or neural crest cells in living zebrafish embryos. This method is used to examine cellular behaviors and actin localization using fluorescence confocal time-lapse microscopy.

Live-Imaging von Zellbewegung und Aktin-Zytoskelett von einzelnen Neuronen und Zellen der Neuralleiste in Zebrafisch-Embryos

The zebrafish is an ideal model for imaging cell behaviors during development in vivo. Zebrafish embryos are externally fertilized and thus easily ...

Transplantation of GFP-expressing Blastomeres for Live Imaging of Retinal and Brain Development in Chimeric Zebrafish Embryos

Cells change extensively in their locations and property during embryogenesis. These changes are regulated by the interactions between the cells and their environment. Chimeric embryos, which are composed of cells of different genetic background, are great tools to study the cell-cell interactions mediated by genes of interest. The embryonic transparency of zebrafish at early developmental stages permits direct visualization of the morphogenesis of tissues and organs at the cellular level. Here, we demonstrate a protocol to generate chimeric retinas and brains in zebrafish embryos and to perform live imaging of the donor cells. The protocol covers the preparation of transplantation needles, the transplantation of GFP-expressing donor blastomeres to GFP-negative hosts, and the examination of donor cell behavior under live confocal microscopy. With slight modifications, this protocol can also be used to study the embryonic development of other tissues and organs in zebrafish. The advantages of using GFP to label donor cells are also discussed. 

We demonstrate a protocol to generate chimeric zebrafish embryos for live imaging cellular behavior during embryogenesis.

Die Transplantation von GFP-exprimierenden Blastomeren für Live Imaging von Retinal und Entwicklung des Gehirns in Chimäre Zebrafischembryonen

Cells change extensively in their locations and property during embryogenesis. These changes are regulated by the interactions between the cells and their ...

Do-It-Yourself Device for Recovery of Cryopreserved Samples Accidentally Dropped into Cryogenic Storage Tanks

Liquid nitrogen is colorless, odorless, extremely cold (-196 &deg;C) liquid kept under pressure. It is commonly used as a cryogenic fluid for long term storage of biological materials such as blood, cells and tissues 1,2. The cryogenic nature of liquid nitrogen, while ideal for sample preservation, can cause rapid freezing of live tissues on contact - known as 'cryogenic burn'2, which may lead to severe frostbite in persons closely involved in storage and retrieval of samples from Dewars. Additionally, as liquid nitrogen evaporates it reduces the oxygen concentration in the air and might cause asphyxia, especially in confined spaces2.
In laboratories, biological samples are often stored in cryovials or cryoboxes stacked in stainless steel racks within the Dewar tanks1. These storage racks are provided with a long shaft to prevent boxes from slipping out from the racks and into the bottom of Dewars during routine handling. All too often, however, boxes or vials with precious samples slip out and sink to the bottom of liquid nitrogen filled tank. In such cases, samples could be tediously retrieved after transferring the liquid nitrogen into a spare container or discarding it. The boxes and vials can then be relatively safely recovered from emptied Dewar. However, the cryogenic nature of liquid nitrogen and its expansion rate makes sunken sample retrieval hazardous. It is commonly recommended by Safety Offices that sample retrieval be never carried out by a single person. Another alternative is to use commercially available cool grabbers or tongs to pull out the vials3. However, limited visibility within the dark liquid filled Dewars poses a major limitation in their use.
In this article, we describe the construction of a Cryotolerant DIY retrieval device, which makes sample retrieval from Dewar containing cryogenic fluids both safe and easy.

Here we present a low cost, durable cryotolerant device for sample retrieval from Dewar tanks filled with liquid nitrogen. The ease of construction and modular design of the device makes the process of sample retrieval from cryogenic tanks safe and easy.

Do-It-Yourself Einrichtung zur Rückgewinnung von kryokonservierten Proben versehentlich fallengelassen in Kryo-Lagerbehälter

Liquid nitrogen is colorless, odorless, extremely cold (-196 &deg;C) liquid kept under pressure. It is commonly used as a cryogenic fluid for long term ...

Live Imaging of Apoptotic Cell Clearance during Drosophila Embryogenesis

The proper elimination of unwanted or aberrant cells through apoptosis and subsequent phagocytosis (apoptotic cell clearance) is crucial for normal development in all metazoan organisms. Apoptotic cell clearance is a highly dynamic process intimately associated with cell death; unengulfed apoptotic cells are barely seen in vivo under normal conditions. In order to understand the different steps of apoptotic cell clearance and to compare 'professional' phagocytes - macrophages and dendritic cells to 'non-professional' - tissue-resident neighboring cells, in vivo live imaging of the process is extremely valuable. Here we describe a protocol for studying apoptotic cell clearance in live Drosophila embryos. To follow the dynamics of different steps in phagocytosis we use specific markers for apoptotic cells and phagocytes. In addition, we can monitor two phagocyte systems in parallel: 'professional' macrophages and 'semi-professional' glia in the developing central nervous system (CNS). The method described here employs the Drosophila embryo as an excellent model for real time studies of apoptotic cell clearance.

Live Imaging of Apoptotic Cell Clearance during Drosophila Embryogenesis

Here we describe an effective method for studying dynamics of apoptotic cell clearance in vivo. This method employs live Drosophila embryos as a powerful model for monitoring phagocytosis of apoptotic cells using specific labeling of apoptotic cells and phagocytes.

Live-Imaging von apoptotischen Ausverkauf während<em&gt; Drosophila</em&gt; Embryogenese

The  proper elimination of unwanted or aberrant cells through apoptosis and  subsequent phagocytosis (apoptotic cell clearance) is crucial for normal  ...

Intravital Microscopy for Imaging Subcellular Structures in Live Mice Expressing Fluorescent Proteins

Here we describe a procedure to image subcellular structures in live rodents that is based on the use of confocal intravital microscopy. As a model organ, we use the salivary glands of live mice since they provide several advantages. First, they can be easily exposed to enable access to the optics, and stabilized to facilitate the reduction of the motion artifacts due to heartbeat and respiration. This significantly facilitates imaging and tracking small subcellular structures. Second, most of the cell populations of the salivary glands are accessible from the surface of the organ. This permits the use of confocal microscopy that has a higher spatial resolution than other techniques that have been used for in vivo imaging, such as two-photon microscopy. Finally, salivary glands can be easily manipulated pharmacologically and genetically, thus providing a robust system to investigate biological processes at a molecular level.
In this study we focus on a protocol designed to follow the kinetics of the exocytosis of secretory granules in acinar cells and the dynamics of the apical plasma membrane where the secretory granules fuse upon stimulation of the beta-adrenergic receptors. Specifically, we used a transgenic mouse that co-expresses cytosolic GFP and a membrane-targeted peptide fused with the fluorescent protein tandem-Tomato. However, the procedures that we used to stabilize and image the salivary glands can be extended to other mouse models and coupled to other approaches to label in vivo cellular components, enabling the visualization of various subcellular structures, such as endosomes, lysosomes, mitochondria, and the actin cytoskeleton.

Intravital microscopy is a powerful tool that enables imaging various biological processes in live animals. In this article, we present a detailed method for imaging the dynamics of subcellular structures, such as the secretory granules, in the salivary glands of live mice.

Intravitalmikroskopie zur Imaging subzellulärer Strukturen in lebenden Mäusen Ausdruck Fluoreszierende Proteine

Here we describe a procedure to image subcellular structures in live rodents that is based on the use of confocal intravital microscopy. As a model organ, ...

Endothelial Cell Tube Formation Assay for the In Vitro Study of Angiogenesis

Angiogenesis is a vital process for normal tissue development and wound healing, but is also associated with a variety of pathological conditions. Using this protocol, angiogenesis may be measured in vitro in a fast, quantifiable manner. Primary or immortalized endothelial cells are mixed with conditioned media and plated on basement membrane matrix. The endothelial cells form capillary like structures in response to angiogenic signals found in conditioned media. The tube formation occurs quickly with endothelial cells beginning to align themselves within 1&#160;hr and lumen-containing tubules beginning to appear within 2 hr. Tubes can be visualized using a phase contrast inverted microscope, or the cells can be treated with calcein AM prior to the assay and tubes visualized through fluorescence or confocal microscopy. The number of branch sites/nodes, loops/meshes, or number or length of tubes formed can be easily quantified as a measure of in vitro angiogenesis. In summary, this assay can be used to identify genes and pathways that are involved in the promotion or inhibition of angiogenesis in a rapid, reproducible, and quantitative manner.

Endothelial Cell Tube Formation Assay for the In Vitro Study of Angiogenesis

The tube formation assay is a fast, quantifiable method for measuring in vitro angiogenesis. Endothelial cells are combined with conditioned media and plated on basement membrane extract. Tube formation occurs within hours and newly formed tubules easily quantified.

Endothelzellen Schlauchbildung Assay für die<em&gt; In-vitro-</em&gt; Studium der Angiogenese

Angiogenesis is a vital process for normal tissue development and wound healing, but is also associated with a variety of pathological conditions. Using ...