Und Anschubfinanzierung von Albert Einstein College of Medicine; Diese Arbeit wurde teilweise durch die National Institutes of Health (3U54AI057158-06S1 zu RDS GM093282 zu PW) unterstützt.

1. Egg Collection und Dechorionation <ol><li> Sammeln und Transfer Zebrafisch-Eier zu 35mm Petrischale, so viel Wasser wie möglich zu entfernen und fügen Sie dann 1 mg / ml Pronease E in E3 Embryo Medium (5 mM NaCl, 0,17 mM KCl, 0,33 mM CaCl 2 · 2H 2 O, 0,33 mM MgSO 4, pH = 7,4), um das Chorion zu verdauen. </li><li> Nach 3-5 Minuten verschmelzen die Schüssel in ein Becherglas mit Fisch Wasser (60 mg &quot;Instant Ocean&quot; pro Liter destilliertem H 2 O) gefüllt und sanft Übertragung der Eier in das Becherglas und lassen die Eier zu &quot;stürzen&quot; ins Wasser. </li><li> Spülen Sie die Eier mit Fisch Wasser dreimal. Die meisten Eier werden aus ihren Chorion veröffentlicht werden. </li><li> Mit einem Feuer-poliertem Glas Pasteur Pipette die dechorionated Eier Agarose beschichteten Petrischalen mit E3 Embryo Medium gefüllt ist. </li></ol> 2. Mikroinjektion mit einem BIP-FucAl <ol><li> Bereiten Sie die Injektion Gerichte nach dem Berichtsmonat Protokoll 7. </li><li> Transfer dechorionated Eier in Injektion Gerichte mit E3 Embryo Medium gefüllt ist. </li><li> Bereiten Sie die Nadel und Last mit 2 ul Injektionslösung. Diese Lösung enthält 20 mM GDP-FucAl synthetisiert chemoenzymatisch 8 und entweder Alexa Fluor 594-Dextran (5% w / v) als Tracer oder Phenolrot Loading Dye (0,1% w / v) in 0,2 M KCl. Als Negativ-Kontrolle, ersetzen BIP-FucAl mit GDP-Fucose in Injektionslösung. </li><li> Break the Nadel und stellen Sie den Einspritzdruck und die Dauer einer 1 nL drop 9 ergeben. </li><li> Spritzen Sie die Eier mit 1 nL der jeweiligen Lösung. </li><li> Übertragen Sie die Eier in Agarose-beschichteten Petrischalen mit E3 Embryo Medium gefüllt ist. </li><li> Inkubieren Eier bei 28 ° C und entfernen Sie die unbefruchteten Eier in drei Minuten vor vier Stunden nach der Befruchtung. </li></ol> 3. BTTES-Cu (I)-katalysierten Klick-Chemie Reaction <ol><li> Wenn die Embryonen erreichen Entwicklungsstadien (zB verspätete Gastrula-, Gewebe-Segmentierung und der frühen Larve), Mantel der Basis einer 96-Well-Platte mit Agarose gewünscht. </li><li> Add 92 ul E3 Embryo Medium in jede Vertiefung, durch Zugabe von 4 ul Alexa Fluor-488-Azid gefolgt (von 2,5 mM Lager in H 2 O), 2 ul BTTES-CuSO 4 6.01 komplex, und schütteln Sie sie leicht zu mischen. </li><li> Transfer-Embryonen in den Brunnen mit dem Klick-Chemie-Reagenz mit einem Feuer-poliertem Glas Pasteur Pipette. Jedes der gut sollte weniger als fünf Embryonen. </li><li> Add 2,5 ul frisch zubereiteten Natriumascorbat (von 100 mM Lager in H 2 O), um die Klick-Reaktion 3 einzuleiten. Endkonzentration jedes Reagenz: Alexa Fluor-488-Azid: 100 nM; CuSO 4: 50 uM; BTTES: 300 nM; Natriumascorbat: 2,5 mm. </li><li> Nach 3 min, add 2 ul Bathocuproin sulfonat (50 mM Lager in H 2 O), einem biokompatiblen Kupfer-Chelator, um die Reaktion dann zu löschen verdünnen sofort mit 100 ul E3 Embryo Medium. </li><li> Übertragen Sie die Embryonen einer Glas-Petrischale und waschen Sie die behandelten Embryonen 2 mal mit 15 mL E3 Embryo Medium. </li></ol> 4. Imaging <ol><li> Geben Sie einen Tropfen extrem niedrigen Schmelzpunkt Agarose (1,2% (w / v) in E3 Embryo medium) auf einem MatTek Glasboden Mikrotiterplatten Schale und setzen ein Embryo in die Agarose fallen. </li><li> Position der Embryonen dorsal oder lateral und die Schale auf Eis für 5 min auf die Agarose Tropfen erstarren. Add E3 Embryo Medium vorsichtig in die Schale, bis sie die Agarose Tropfen abdeckt. </li><li> Fluoreszenz-und Hellfeld-Bilder erworben werden nacheinander mit einem konfokalen Mikroskop. Alle Embryo Bilder aufgenommen mit einem 5 um Schritt Intervall. Zusammengesetzte Zahlen werden unter Verwendung von ImageJ-Software. </li></ol> 5. Repräsentative Ergebnisse Abbildung 1 zeigt den Workflow unserer Zwei-Schritt-Kennzeichnung Strategie. Abbildung 2 zeigt die Kennzeichnung von Zebrafisch-Embryonen via BTTES-vermittelte CuAAC bei 9,5 Stunden nach der Befruchtung (HPF). BTTES ist ein Tris (triazolylmethyl) amin-Liganden. Er beschleunigt CuAAC dramatisch, wenn die Abstimmung mit den in situ erzeugten Cu (I), und fördert die Cycloaddition schnell in lebenden Systemen ohne erkennbare Toxizität. Unmittelbar nach einem 3-min-Klick-Reaktion, sind wir in der Lage, robuste Kennzeichnung des BIP-FucAl behandelten Embryonen (Abbildung 2, linkes Bild) zu erkennen. Nur Hintergrundfluoreszenz wird für die Steuerung von Embryonen mit GDP-Fucose (Abbildung 2, rechts Panels) mikroinjiziert erkannt. <img src="/files/ftp_upload/2686/2686fig1.jpg" alt="Abbildung 1" /> Abbildung 1. Die Strategie der Kennzeichnung fucosylierte Glykane in der umhüllenden Schicht von Zebrafisch-Embryonen. <img src="/files/ftp_upload/2686/2686fig2.jpg" alt="Abbildung 2" /> Abbildung 2. In-vivo-Bildgebung von fucosylierte Glykane in Zebrafisch-Embryogenese über BTTES-Cu (I)-katalysierten Klick-Chemie. Ein-Zell-Stadium Zebrafischembryonen sind mit einer einzigen Dosis des BIP-FucAl mikroinjiziert und dürfen develop auf 9,5 hpf. Die Embryonen werden dann mit Alexa Fluor 488-Azid, katalysiert durch BTTES-Cu (I) umgesetzt. Reagierte Embryonen abgebildet werden mit Hilfe der konfokalen Mikroskopie. Maximale Intensität z-Projektion Bilder von Alexa Fluor 488-Fluoreszenz (oberes Bild); Hellfeld (unteres Bild). Maßstab: 100 um. Fehlerbehebung <table border="1"><tbody><tr><td> Problem </td><td> Ursache </td><td> Abhilfe </td></tr><tr><td> Die Embryonen ungesund aussehen </td><td> Die mikroinjiziert Lösung enthält Schadstoffe </td><td> Die Reinheit des Nucleotidzucker sollte größer sein als 85%. Überprüfen Sie Ihre Hand. </td></tr><tr><td> Es gibt keine Kennzeichnung nach der Reaktion </td><td> Kupfer-Konzentration unterhalb von 30 pM </td><td> Achten Sie darauf, die Reaktionslösung durch Zugabe überschüssiger E3 Embryo Medium bei Zugabe der Embryonen, wie die Reaktionsgeschwindigkeit sinkt deutlich, wenn die Kupfer-Konzentration unter 30 uM zu verdünnen. </td></tr><tr><td> Die Embryonen sterben nach der Reaktion </td><td> Unsachgemäße Behandlung der Embryonen </td><td> Sicherstellen, dass die Pipette ist feuerpolierte und das Reaktionsgefäß mit einer sehr dünnen Schicht von 0,5% Agarose beschichtet. </td></tr><tr><td> Die Bilder sehen fleckig </td><td> Die Reagenzien sind nicht richtig, bevor Sie die Embryonen gemischt </td><td> Befolgen Sie die empfohlene Reihenfolge der Zugabe der Reagenzien, und stellen Sie sicher, dass der Klick-Chemie Reagenzien wurden ordnungsgemäß vor der Zugabe des Embryos vermischt. </td></tr><tr><td> Die Bilder zeigen die Embryonen geschädigt werden </td><td> Heftiges Schütteln Schäden die Embryonen während der Reaktion </td><td> Sanft für weniger als 10 Sekunden schütteln, wenn die Embryonen in der Lösung sind. </td></tr><tr><td></td><td></td><td></td></tr></tbody></table>

<ol>
	<li>Laughlin, S. T., Bertozzi, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+the+glycome.">Imaging the glycome.</a> Proc. Natl. Acad. Sci. U. S. A. 106, 12-17 (2009).</li><li>Baskin, J. M., Bertozzi, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioorthogonal+click+chemistry:+Covalent+labeling+in+living+systems.">Bioorthogonal click chemistry: Covalent labeling in living systems.</a> Qsar Comb. Sci. 26, 1211-1219 (2007).</li><li>Soriano del Amo, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biocompatible+copper(I)+catalysts+for+in+vivo+imaging+of+glycans.">Biocompatible copper(I) catalysts for in vivo imaging of glycans.</a> J. Am. Chem. Soc. 132, 16893-16899 (2010).</li><li>Chang, P. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic+labeling+of+sialic+acids+in+living+animals+with+alkynyl+sugars.">Metabolic labeling of sialic acids in living animals with alkynyl sugars.</a> Angew. Chem. Int. Ed. 48, 4030-4033 (2009).</li><li>Laughlin, S. T., Baskin, J. M., Amacher, S. L., Bertozzi, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+imaging+of+membrane-associated+glycans+in+developing+zebrafish.">In vivo imaging of membrane-associated glycans in developing zebrafish.</a> Science. 320, 664-667 (2008).</li><li>Baskin, J. M., Dehnert, K. W., Laughlin, S. T., Amacher, S. L., Bertozzi, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+enveloping+layer+glycans+during+zebrafish+early+embryogenesis.">Visualizing enveloping layer glycans during zebrafish early embryogenesis.</a> Proc. Natl. Acad. Sci. U. S. A. 107, 10360-10365 (2010).</li><li>Kemp, H. A., Carmany-Rampey, A., Moens, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generating+chimeric+zebrafish+embryos+by+transplantation.">Generating chimeric zebrafish embryos by transplantation.</a> J. Vis. Exp. , (2009).</li><li>Wang, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemoenzymatic+synthesis+of+GDP-L-fucose+and+the+Lewis+X+glycan+derivatives.">Chemoenzymatic synthesis of GDP-L-fucose and the Lewis X glycan derivatives.</a> Proc. Natl. Acad. Sci. U. S. A. 106, 16096-16101 (2009).</li><li>Rosen, J. N., Sweeney, M. F., Mably, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microinjection+of+zebrafish+embryos+to+analyze+gene+function.">Microinjection of zebrafish embryos to analyze gene function.</a> J. Vis. Exp. , (2009).</li><li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> THE ZEBRAFISH BOOK, A guide for the laboratory use of zebrafish (Danio rerio). , (2007).</li><li>Kimmel, C. B., Warga, R. M., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Origin+and+organization+of+the+zebrafish+fate+map.">Origin and organization of the zebrafish fate map.</a> Development. 108, 581-594 (1990).</li></ol>

<p class="jove_content"&gt; Imaging Biomolekülen<em&gt; In vivo</em&gt; Liefert wichtige Erkenntnisse ihrer biologischen Aktivitäten in ihrer natürlichen Umgebung. In diesem Video zeigen wir, wie die Kennzeichnung von fucosylierte Glykane in der umhüllenden Schicht von Zebrafisch-Embryonen durch Mikroinjektion one-Zell-Stadium Embryos mit einem BIP-FucAl und eine zweite für-Schritt-Fluorophor Konjugation über BTTES-vermittelte biokompatiblen CuAAC realisiert<sup&gt; 3</sup&gt;. Robust Kennzeichnung kann innerhalb von 2-3 Minuten erreicht ...

<table border="1"><tbody><tr><td> Name des Reagenzes </td><td> Firma </td><td> Katalog-Nummer </td></tr><tr><td> Kupfer (II)-sulfat-Pentahydrat </td><td> Sigma-Aldrich </td><td> 203165 </td></tr><tr><td> Alexa Fluor 488 Azid </td><td> Invitrogen </td><td> A10266 </td></tr><tr><td> Dextran, Alexa Fluor 594 </td><td> Invitrogen </td><td> D-22913 </td></tr><tr><td> (+)-Natrium-L-Ascorbat </td><td> Sigma-Aldrich </td><td> A7631 </td></tr><tr><td> Bathocuproinedisulfonic Säure </td><td> Acros Organics </td><td> 164060010 </td></tr><tr><td> Glasboden Mikrotiterplatten Gericht </td><td> MatTek </td><td> P35G-1,5-14-C </td></tr></tbody></table>

imaging glycans in zebrafish embryos by metabolic labeling and bioorthogonal click chemistry

Imaging Glykane in vivo wurde vor kurzem durch die Verwendung einer bioorthogonale chemischen Reporter, indem man Zellen oder Organismen mit Azid-oder Alkin-markierten Monosacchariden 1, 2. Die modifizierte Monosaccharide, durch die Glykan Biosynthese-Maschinerie verarbeitet, sind in der Zelloberfläche Glycokonjugate eingearbeitet. Die bioorthogonale Azid-oder Alkin-Tags dann eine kovalente Konjugation mit fluoreszierenden Sonden für die Visualisierung oder mit Affinitätssonden zur Anreicherung und glycoproteomic Analyse. Dieses Protokoll beschreibt die Verfahren in der Regel für nicht-invasive Bildgebung von fucosylierte Glykane in Zebrafisch-Embryonen verwendet werden, einschließlich: 1) Mikroinjektion von one-Zell-Stadium Embryos mit einem BIP-5-alkynylfucose (BIP-FucAl), 2) Kennzeichnung fucosylierte Glykane in der umhüllenden Schicht aus Zebrafisch-Embryos mit Azid-konjugierten Fluorophore über biokompatible Cu (I)-katalysierten Azid-Alkin-Cycloaddition (CuAAC) und 3) Bildgebung durch konfokale Mikroskopie 3. Die hier beschriebene Methode kann leicht erweitert werden, um andere Klassen von Glykane, zB Glykane mit Sialinsäure 4 und N-Acetyl-5, 6, bei der Entwicklung von Zebrafisch und in anderen Lebewesen zu visualisieren.

Watch this Scientific Journal Video about Imaging Glycans in Zebrafish Embryos by Metabolic Labeling and Bioorthogonal Click Chemistry at JoVE.com

Imaging Glycans in Zebrafish Embryos by Metabolic Labeling and Bioorthogonal Click Chemistry

Ein Klick-Chemie basierende Methode, die für die schnelle, nichtinvasive und robuste Kennzeichnung von Alkin-markierten Glykane in Zebrafisch-Embryonen erlaubt wird beschrieben. Fucosylierte Glykane in der umhüllenden Schicht von Zebrafisch-Embryonen in den späten Gastrulation Bühne wurden in dieser Studie abgebildet.

Imaging Glykane in Zebrafisch-Embryonen durch metabolische Markierung und Bioorthogonale Click-Chemie

Imaging glycans in vivo has recently been enabled using a bioorthogonal chemical reporter strategy by treating cells or organisms with azide- or ...

imaging-glycans-zebrafish-embryos-metabolic-labeling-bioorthogonal

Research

JoVE Journal

Biology

13.5K Aufrufe.  Albert Einstein College of Medicine, Yeshiva University. Ein Klick-Chemie basierende Methode, die für die schnelle, nichtinvasive und robuste Kennzeichnung von Alkin-markierten Glykane in Zebrafisch-Embryonen erlaubt wird beschrieben. Fucosylierte Glykane in der umhüllenden Schicht von Zebrafisch-Embryonen in den späten Gastrulation Bühne wurden in dieser Studie abgebildet.

Serie: Imaging Glycans in Zebrafish Embryos by Metabolic Labeling and Bioorthogonal Click Chemistry

Microinjection of mRNA and Morpholino Antisense Oligonucleotides in Zebrafish Embryos.

An essential tool for investigating the role of a gene during development is the ability to perform gene knockdown, overexpression, and misexpression studies. In zebrafish (Danio rerio), microinjection of RNA, DNA, proteins, antisense oligonucleotides and other small molecules into the developing embryo provides researchers a quick and robust assay for exploring gene function in vivo. In this video-article, we will demonstrate how to prepare and microinject in vitro synthesized EGFP mRNA and a translational-blocking morpholino oligo against pkd2, a gene associated with autosomal dominant polycystic kidney disease (ADPKD), into 1-cell stage zebrafish embryos. We will then analyze the success of the mRNA and morpholino microinjections by verifying GFP expression and phenotype analysis. Broad applications of this technique include generating transgenic animals and germ-line chimeras, cell-fate mapping and gene screening. Herein we describe a protocol for overexpression of EGFP and knockdown of pkd2 by mRNA and morpholino oligonucleotide injection.

Microinjection is a well-established and effective method for introducing foreign substances into fertilized zebrafish embryos. Here, we demonstrate a robust microinjection technique for performing mRNA overexpression, and morpholino oligonucleotide gene knockdown studies in zebrafish.

Mikroinjektion von mRNA und Morpholino Antisense Oligonukleotide in Zebrafisch-Embryonen.

An essential tool for investigating the role of a gene during development is the ability to perform gene knockdown, overexpression, and misexpression ...

Forschung

Biologie

Two-photon axotomy and time-lapse confocal imaging in live zebrafish embryos

Zebrafish have long been utilized to study the cellular and molecular mechanisms of development by time-lapse imaging of the living transparent embryo. Here we describe a method to mount zebrafish embryos for long-term imaging and demonstrate how to automate the capture of time-lapse images using a confocal microscope. We also describe a method to create controlled, precise damage to individual branches of peripheral sensory axons in zebrafish using the focused power of a femtosecond laser mounted on a two-photon microscope. The parameters for successful two-photon axotomy must be optimized for each microscope. We will demonstrate two-photon axotomy on both a custom built two-photon microscope and a Zeiss 510 confocal/two-photon to provide two examples.

Zebrafish trigeminal sensory neurons can be visualized in a transgenic line expressing GFP driven by a sensory neuron specific promoter 1. We have adapted this zebrafish trigeminal model to directly observe sensory axon regeneration in living zebrafish embryos. Embryos are anesthetized with tricaine and positioned within a drop of agarose as it solidifies. Immobilized embryos are sealed within an imaging chamber filled with phenylthiourea (PTU) Ringers. We have found that embryos can be continuously imaged in these chambers for 12-48 hours. A single confocal image is then captured to determine the desired site of axotomy. The region of interest is located on the two-photon microscope by imaging the sensory axons under low, non-damaging power. After zooming in on the desired site of axotomy, the power is increased and a single scan of that defined region is sufficient to sever the axon. Multiple location time-lapse imaging is then set up on a confocal microscope to directly observe axonal recovery from injury.

Here we describe a method for mounting zebrafish embryos for long-term imaging, two-photon imaging and tissue-damage techniques, and time-lapse confocal imaging.

Zwei-Photonen-Axotomie und Zeitraffer-konfokale Bildgebung in lebenden Zebrafisch-Embryonen

Zebrafish have long been utilized to study the cellular and molecular mechanisms of development by time-lapse imaging of the living transparent embryo.  ...

Generating Chimeric Zebrafish Embryos by Transplantation

One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an organism that contains cells from more than one animal; mosaics are one type of chimera in which cells from more than one genotype are mixed, usually wild-type and mutant. In the zebrafish, chimeras can be readily made by transplantation of cells from a donor embryo into a host embryo at the appropriate embryonic stage. Labeled donor cells are generated by injection of a lineage marker, such as a fluorescent dye, into the one-cell stage embryo. Labeled donor cells are removed from donor embryos and introduced into unlabeled host embryos using an oil-controlled glass pipette mounted on either a compound or dissecting microscope. Donor cells can in some cases be targeted to a specific region or tissue of the developing blastula or gastrula stage host embryo by choosing a transplantation site in the host embryo based on well-established fate maps.

A step-by-step guide to generating targeted chimeric zebrafish embryos by transplantation at the blastula or gastrula stage.

Generieren Chimäre Zebrafischembryonen durch Transplantation

One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an ...

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 ...

Imaging Cell Shape Change in Living Drosophila Embryos

The developing Drosophila melanogaster embryo undergoes a number of cell shape changes that are highly amenable to live confocal imaging. Cell shape changes in the fly are analogous to those in higher organisms, and they drive tissue morphogenesis. So, in many cases, their study has direct implications for understanding human disease (Table 1)1-5. On the sub-cellular scale, these cell shape changes are the product of activities ranging from gene expression to signal transduction, cell polarity, cytoskeletal remodeling and membrane trafficking. Thus, the Drosophila embryo provides not only the context to evaluate cell shape changes as they relate to tissue morphogenesis, but also offers a completely physiological environment to study the sub-cellular activities that shape cells.
The protocol described here is designed to image a specific cell shape change called cellularization. Cellularization is a process of dramatic plasma membrane growth, and it ultimately converts the syncytial embryo into the cellular blastoderm. That is, at interphase of mitotic cycle 14, the plasma membrane simultaneously invaginates around each of ~6000 cortically anchored nuclei to generate a sheet of primary epithelial cells. Counter to previous suggestions, cellularization is not driven by Myosin-2 contractility6, but is instead fueled largely by exocytosis of membrane from internal stores7. Thus, cellularization is an excellent system for studying membrane trafficking during cell shape changes that require plasma membrane invagination or expansion, such as cytokinesis or transverse-tubule (T-tubule) morphogenesis in muscle.
Note that this protocol is easily applied to the imaging of other cell shape changes in the fly embryo, and only requires slight adaptations such as changing the stage of embryo collection, or using "embryo glue" to mount the embryo in a specific orientation (Table 1)8-19. In all cases, the workflow is basically the same (Figure 1). Standard methods for cloning and Drosophila transgenesis are used to prepare stable fly stocks that express a protein of interest, fused to Green Fluorescent Protein (GFP) or its variants, and these flies provide a renewable source of embryos. Alternatively, fluorescent proteins/probes are directly introduced into fly embryos via straightforward micro-injection techniques9-10. Then, depending on the developmental event and cell shape change to be imaged, embryos are collected and staged by morphology on a dissecting microscope, and finally positioned and mounted for time-lapse imaging on a confocal microscope.

Imaging Cell Shape Change in Living Drosophila Embryos

Early development of the fruit fly, Drosophila melanogaster, is characterized by a number of cell shape changes that are well suited for imaging approaches. This article will describe basic tools and methods required for live confocal imaging of Drosophila embryos, and will focus on a cell shape change called cellularization.

Imaging Zellgröße Veränderung der Lebens- Drosophila Embryos

The developing Drosophila melanogaster embryo undergoes a number of cell shape changes that are highly amenable to live confocal imaging.  Cell shape ...

Measuring Cell Cycle Progression Kinetics with Metabolic Labeling and Flow Cytometry

Precise control of the initiation and subsequent progression through the various phases of the cell cycle are of paramount importance in proliferating cells. Cell cycle division is an integral part of growth and reproduction and deregulation of key cell cycle components have been implicated in the precipitating events of carcinogenesis 1,2. Molecular agents in anti-cancer therapies frequently target biological pathways responsible for the regulation and coordination of cell cycle division 3. Although cell cycle kinetics tend to vary according to cell type, the distribution of cells amongst the four stages of the cell cycle is rather consistent within a particular cell line due to the consistent pattern of mitogen and growth factor expression. Genotoxic events and other cellular stressors can result in a temporary block of cell cycle progression, resulting in arrest or a temporary pause in a particular cell cycle phase to allow for instigation of the appropriate response mechanism. 
The ability to experimentally observe the behavior of a cell population with reference to their cell cycle progression stage is an important advance in cell biology. Common procedures such as mitotic shake off, differential centrifugation or flow cytometry-based sorting are used to isolate cells at specific stages of the cell cycle 4-6. These fractionated, cell cycle phase-enriched populations are then subjected to experimental treatments. Yield, purity and viability of the separated fractions can often be compromised using these physical separation methods. As well, the time lapse between separation of the cell populations and the start of experimental treatment, whereby the fractionated cells can progress from the selected cell cycle stage, can pose significant challenges in the successful implementation and interpretation of these experiments.
Other approaches to study cell cycle stages include the use of chemicals to synchronize cells. Treatment of cells with chemical inhibitors of key metabolic processes for each cell cycle stage are useful in blocking the progression of the cell cycle to the next stage. For example, the ribonucleotide reductase inhibitor hydroxyurea halts cells at the G1/S juncture by limiting the supply of deoxynucleotides, the building blocks of DNA. Other notable chemicals include treatment with aphidicolin, a polymerase alpha inhibitor for G1 arrest, treatment with colchicine and nocodazole, both of which interfere with mitotic spindle formation to halt cells in M phase and finally, treatment with the DNA chain terminator 5-fluorodeoxyridine to initiate S phase arrest 7-9. Treatment with these chemicals is an effective means of synchronizing an entire population of cells at a particular phase. With removal of the chemical, cells rejoin the cell cycle in unison. Treatment of the test agent following release from the cell cycle blocking chemical ensures that the drug response elicited is from a uniform, cell cycle stage-specific population. However, since many of the chemical synchronizers are known genotoxic compounds, teasing apart the participation of various response pathways (to the synchronizers vs. the test agents) is challenging. 
Here we describe a metabolic labeling method for following a subpopulation of actively cycling cells through their progression from the DNA replication phase, through to the division and separation of their daughter cells. Coupled with flow cytometry quantification, this protocol enables for measurement of kinetic progression of the cell cycle in the absence of either mechanically- or chemically- induced cellular stresses commonly associated with other cell cycle synchronization methodologies 10. In the following sections we will discuss the methodology, as well as some of its applications in biomedical research.

Tracking subtle changes in the progression and kinetics of cell cycle stages can be accomplished by use of a combination of metabolic labeling of nucleic acids with BrdU and total genomic DNA staining via Propidium Iodide. This method avoids the need of chemical synchronization of cycling cells, thereby preventing the introduction of non-specific DNA damage, which in turn affects cell cycle progression.

Mess-Zellzyklus-Progression Kinetics mit Metabolische Markierung und Durchflusszytometrie

Precise control of the initiation and subsequent progression through the various phases of the cell cycle are of paramount importance in proliferating ...

Metabolic Profile Analysis of Zebrafish Embryos

A growing goal in the field of metabolism is to determine the impact of genetics on different aspects of mitochondrial function. Understanding these relationships will help to understand the underlying etiology for a range of diseases linked with mitochondrial dysfunction, such as diabetes and obesity. Recent advances in instrumentation, has enabled the monitoring of distinct parameters of mitochondrial function in cell lines or tissue explants. Here we present a method for a rapid and sensitive analysis of mitochondrial function parameters in vivo during zebrafish embryonic development using the Seahorse bioscience XF 24 extracellular flux analyser. This protocol utilizes the Islet Capture microplates where a single embryo is placed in each well, allowing measurement of bioenergetics, including: (i) basal respiration; (ii) basal mitochondrial respiration (iii) mitochondrial respiration due to ATP turnover; (iv) mitochondrial uncoupled respiration or proton leak and (iv) maximum respiration. Using this approach embryonic zebrafish respiration parameters can be compared between wild type and genetically altered embryos (mutant, gene over-expression or gene knockdown) or those manipulated pharmacologically. It is anticipated that dissemination of this protocol will provide researchers with new tools to analyse the genetic basis of metabolic disorders in vivo in this relevant vertebrate animal model.

Zebrafish represent a powerful vertebrate model that has been under-utilised for metabolic studies. Here we describe a rapid way to measure the in vivo metabolic profile of developing zebrafish that allows the comparison of different mitochondrial function parameters between genetically or pharmacologically manipulated embryos, thereby increasing the applicability of this organism.

Metabolic-Profil-Analyse von Zebrafischembryonen

A growing goal in the field of metabolism is to determine the impact of genetics on different aspects of mitochondrial function. Understanding these ...

Analysis of Apoptosis in Zebrafish Embryos by Whole-mount Immunofluorescence to Detect Activated Caspase 3

Whole-mount immunofluorescence to detect activated Caspase 3 (Casp3 assay) is useful to identify cells undergoing either intrinsic or extrinsic apoptosis in zebrafish embryos. The whole-mount analysis provides spatial information in regard to tissue specificity of apoptosing cells, although sectioning and/or colabeling is ultimately required to pinpoint the exact cell types undergoing apoptosis. The whole-mount Casp3 assay is optimized for analysis of fixed embryos between the 4-cell stage and 32 hr-post-fertilization and is useful for a number of applications, including analysis of zebrafish mutants and morphants, overexpression of mutant and wild-type mRNAs, and exposure to chemicals. Compared to acridine orange staining, which can identify apoptotic cells in live embryos in a matter of hours, Casp3 and TUNEL assays take considerably longer to complete (2-4 days). However, because of the dynamic nature of apoptotic cell formation and clearance, analysis of fixed embryos ensures accurate comparison of apoptotic cells across multiple samples at specific time points. We have also found the Casp3 assay to be superior to analysis of apoptotic cells by the whole-mount TUNEL assay in regard to cost and reliability. Overall, the Casp3 assay represents a robust, highly reproducible assay in which to analyze apoptotic cells in early zebrafish embryos.

Certain genetic perturbations or exposure to toxins can disrupt normal developmental processes leading to death of specific cell types. The analysis of activated Caspase 3 by whole-mount immunofluorescence in zebrafish embryos reveals stage- and tissue-specific localization of cells specifically undergoing apoptosis.

Die Analyse der Apoptose in Zebrafischembryonen von Whole-mount Immunfluoreszenz an aktivierte Caspase 3 Detect

Whole-mount immunofluorescence to detect activated Caspase 3 (Casp3 assay) is useful to identify cells undergoing either intrinsic or extrinsic apoptosis ...

Analysis of Oxidative Stress in Zebrafish Embryos

High levels of reactive oxygen species (ROS) may cause a change of cellular redox state towards oxidative stress condition. This situation causes oxidation of molecules (lipid, DNA, protein) and leads to cell death. Oxidative stress also impacts the progression of several pathological conditions such as diabetes, retinopathies, neurodegeneration, and cancer. Thus, it is important to define tools to investigate oxidative stress conditions not only at the level of single cells but also in the context of whole organisms. Here, we consider the zebrafish embryo as a useful in vivo system to perform such studies and present a protocol to measure in vivo oxidative stress. Taking advantage of fluorescent ROS probes and zebrafish transgenic fluorescent lines, we develop two different methods to measure oxidative stress in vivo: i) a &#8220;whole embryo ROS-detection method&#8221; for qualitative measurement of oxidative stress and ii) a &#8220;single-cell&#160;ROS detection method&#8221; for quantitative measurements of oxidative stress. Herein, we demonstrate the efficacy of these procedures by increasing oxidative stress in tissues by oxidant agents and physiological or genetic methods. This protocol is amenable for forward genetic screens and it will help address cause-effect relationships of ROS in animal models of oxidative stress-related pathologies such as neurological disorders and cancer.

Here we report a protocol to measure oxidative stress in living zebrafish embryos. This procedure allows reactive oxygen species (ROS) detection in both whole embryo tissues and single-cell populations. This protocol will accomplish both qualitative and quantitative analyses.

Analyse von oxidativem Stress in Zebrafischembryonen

High levels of reactive oxygen species (ROS) may cause a change of cellular redox state towards oxidative stress condition. This situation causes ...

Semi-automated Imaging of Tissue-specific Fluorescence in Zebrafish Embryos

Zebrafish embryos are a powerful tool for large-scale screening of small molecules. Transgenic zebrafish that express fluorescent reporter proteins are frequently used to identify chemicals that modulate gene expression. Chemical screens that assay fluorescence in live zebrafish often rely on expensive, specialized equipment for high content screening. We describe a procedure using a standard epifluorescence microscope with a motorized stage to automatically image zebrafish embryos and detect tissue-specific fluorescence. Using transgenic zebrafish that report estrogen receptor activity via expression of GFP, we developed a semi-automated procedure to screen for estrogen receptor ligands that activate the reporter in a tissue-specific manner. In this video we describe procedures for arraying zebrafish embryos at 24-48 hours post fertilization (hpf) in a 96-well plate and adding small molecules that bind estrogen receptors. At 72-96 hpf, images of each well from the entire plate are automatically collected and manually inspected for tissue-specific fluorescence. This protocol demonstrates the ability to detect estrogens that activate receptors in heart valves but not in liver.

Described here is a protocol for semi-automated imaging of tissue-specific fluorescence in zebrafish embryos.

Semi-Automated Imaging von Gewebespezifische Fluoreszenz-in Zebrafischembryonen

Zebrafish embryos are a powerful tool for large-scale screening of small molecules. Transgenic zebrafish that express fluorescent reporter proteins are ...