Questo lavoro è stato in parte sostenuto dal National Institutes of Health (GM093282 di PW; 3U54AI057158-06S1 a RDS) e fondi di avvio di Albert Einstein College of Medicine.

1. Uovo Raccolta e Dechorionation <ol><li> Raccogliere e trasferire le uova di pesce zebra piatto 35 millimetri di Petri, rimuovere l&#39;acqua il più possibile e si aggiunge 1 mg / ml E Pronease nel medio embrione E3 (5 mM NaCl, 0,17 mM KCl, 0,33 mM CaCl 2 · 2H 2 O, 0,33 mM MgSO 4, pH = 7,4) per digerire il corion. </li><li> Dopo 3-5 minuti, unire il piatto in un bicchiere pieno di pesci d&#39;acqua (60 mg &quot;Ocean istantanea&quot; per litro distillata H 2 O), e delicatamente trasferire le uova nel becher e lasciare le uova di &quot;caduta&quot; in acqua. </li><li> Lavare le uova con pesci d&#39;acqua tre volte. La maggior parte delle uova saranno liberati dalla loro corion. </li><li> Utilizzando un incendio lucidato vetro pipetta Pasteur, trasferire le uova dechorionated di agarosio rivestite piastre di Petri riempite con terreno di embrione E3. </li></ol> 2. Microiniezione con un PIL-FucAl <ol><li> Preparare i piatti dopo l&#39;iniezione del protocollo riportato 7. </li><li> Trasferimento uova dechorionated in piatti pieni di iniezione medio embrione E3. </li><li> Preparare l&#39;ago, e caricare con 2 microlitri soluzione iniettabile. Questa soluzione contiene 20 mM PIL FucAl sintetizzato chemoenzymatically 8 e sia Alexa Fluor 594-destrano (5% w / v) come tracciante o rosso fenolo carico colorante (0,1% w / v) in 0,2 M KCl. Come controllo negativo, sostituire il PIL con un PIL-FucAl-fucosio in soluzione iniettabile. </li><li> Rompere l&#39;ago e regolare la pressione di iniezione e la durata per produrre un 1 goccia nL 9. </li><li> Iniettare le uova con 1 nL di entrambe le soluzioni. </li><li> Trasferire le uova in agarosio rivestite piastre di Petri riempite con terreno di embrione E3. </li><li> Incubare le uova a 28 ° C ed eliminare le uova non fecondate entro tre o quattro ore dopo la fecondazione. </li></ol> 3. BTTES-Cu (I)-catalizzata reazione chimica Clicca <ol><li> Quando gli embrioni raggiungono desiderato stadi di sviluppo (ad esempio gastrula tardiva, la segmentazione dei tessuti e larve presto), cappotto alla base di una piastra da 96 pozzetti con agarosio. </li><li> Aggiungere 92 microlitri di media embrione E3 in ogni pozzetto, seguita da aggiunta di 4 microlitri Alexa Fluor-488 azide (da uno stock 2,5 mm H 2 O), 2 microlitri BTTES-CuSO 4 6:01 complesso, e agitare delicatamente per miscelare. </li><li> Trasferimento degli embrioni nel pozzo contenente il reagente chimico clic utilizzando un incendio lucidato vetro pipetta Pasteur. Ogni bene deve contenere meno di cinque embrioni. </li><li> Aggiungere 2,5 microlitri ascorbato di sodio preparata (da uno stock di 100 mm H 2 O) per iniziare l&#39;attacco su 3. Concentrazione finale di ogni reagente: Alexa Fluor-488 azide: 100 mM; CuSO 4: 50 micron; BTTES: 300 mM; ascorbato di sodio: 2,5 mm. </li><li> Dopo 3 minuti, aggiungere 2 microlitri bathocuproine solfonato (50 mM magazzino in H 2 O), un chelante del rame biocompatibile, per placare la reazione poi diluire subito con 100 microlitri di media embrione E3. </li><li> Trasferire gli embrioni per un piatto di vetro di Petri e lavare gli embrioni trattati 2 volte con 15 ml di media embrione E3. </li></ol> 4. Imaging <ol><li> Mettere una goccia di bassissimo punto di fusione agarosio (1,2% (w / v) in un mezzo embrione E3) su un fondo di vetro piatto MatTek pozzetti, e posto un embrione nella goccia di agarosio. </li><li> Posizionare gli embrioni dorsalmente o lateralmente e posizionare il piatto in ghiaccio per 5 minuti a solidificare la goccia di agarosio. Aggiungi medio E3 embrione dolcemente verso il piatto fino a coprire il calo di agarosio. </li><li> Immagini di campo fluorescenza e luminose vengono acquisiti in sequenza usando un microscopio confocale. Tutte le immagini degli embrioni vengono acquisite utilizzando un intervallo di fase 5 micron. Figure compositi sono stati preparati utilizzando il software ImageJ. </li></ol> 5. Rappresentante Risultati La figura 1 mostra il flusso di lavoro della nostra strategia in due fasi di etichettatura. La Figura 2 mostra l&#39;etichettatura di embrioni di zebrafish via BTTES-mediata CuAAC al 9,5 ore dopo la fecondazione (HPF). BTTES è un (triazolylmethyl) ammina tris a base di legante. Accelera CuAAC drammaticamente quando coordinamento con il Cu generato in situ (I), e promuove la reazione di cicloaddizione rapidamente nei sistemi viventi senza tossicità apparente. Subito dopo un 3-minuti di reazione su, siamo in grado di rilevare l&#39;etichettatura robusta degli embrioni trattati PIL FucAl (Figura 2, pannelli a sinistra). Fluorescenza di fondo è rilevato solo per gli embrioni di controllo microiniettati con il PIL-fucosio (Figura 2, pannelli a destra). <img src="/files/ftp_upload/2686/2686fig1.jpg" alt="Figura 1" /> Figura 1. La strategia di etichettatura glicani fucosylated nello strato avvolgente di embrioni di zebrafish. <img src="/files/ftp_upload/2686/2686fig2.jpg" alt="Figura 2" /> Figura 2. In imaging in vivo di glicani fucosylated durante l&#39;embriogenesi zebrafish via BTTES-Cu (I)-chimica catalizzata clic. Unicellulare embrioni di zebrafish fase sono microiniettati con una singola dose del PIL-FucAl e ha permesso di sviluppoop a 9,5 HPF. Gli embrioni vengono poi reagito con Alexa Fluor 488-azide catalizzata da BTTES-Cu (I). Gli embrioni vengono esposte reagito usando la microscopia confocale. Intensità massima di z-proiezione immagini di Alexa Fluor 488 fluorescenza (pannello superiore); campo Bright (pannello inferiore). Scala grafica: 100 micron. Risoluzione dei problemi <table border="1"><tbody><tr><td> Problema </td><td> Causa </td><td> Rimedio </td></tr><tr><td> Gli embrioni aspetto malsano </td><td> La soluzione microiniettati contiene contaminanti </td><td> La purezza degli zuccheri nucleotide deve essere superiore all&#39;85%. Controlla la tua fonte. </td></tr><tr><td> Non c&#39;è sull&#39;etichetta dopo la reazione </td><td> Concentrazione di rame è inferiore a 30 micron </td><td> Fare attenzione a non diluire la soluzione di reazione con l&#39;aggiunta di eccesso di media embrione E3 quando si aggiungono gli embrioni, come la velocità di reazione diminuisce in maniera significativa quando la concentrazione di rame è inferiore a 30 micron. </td></tr><tr><td> Gli embrioni muoiono dopo la reazione </td><td> Uso improprio degli embrioni </td><td> Assicurarsi che la pipetta è fuoco lucidato e il recipiente di reazione è rivestita con uno strato molto sottile di 0,5% di agarosio. </td></tr><tr><td> Le immagini appaiono spotty </td><td> I reagenti non sono propriamente mescolati prima di aggiungere gli embrioni </td><td> Seguire l&#39;ordine consigliato di aggiunta dei reagenti, e assicurarsi che i reagenti clicca chimica sono stati opportunamente miscelati prima di aggiungere gli embrioni. </td></tr><tr><td> Le immagini mostrano gli embrioni vengono danneggiati </td><td> Vigorosa agitazione danni degli embrioni durante la reazione </td><td> Agitare delicatamente per meno di 10 secondi una volta gli embrioni sono nella soluzione. </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>

Nessun conflitto di interessi dichiarati.

<p class="jove_content"&gt; Imaging biomolecole<em&gt; In vivo</em&gt; Fornisce spunti critici della loro attività biologica nel loro ambiente naturale. In questo video, ci dimostrano come l&#39;etichettatura dei glicani fucosylated nello strato avvolgente di embrioni di zebrafish è realizzato da microinjecting unicellulare embrioni stadio con il PIL-FucAl e una seconda fase coniugazione fluoroforo attraverso BTTES-mediata CuAAC biocompatibile<sup&gt; 3</sup&gt;. Etichettatura robusta può essere raggiunto entro 2-3 minuti, e il glicani etich...

<table border="1"><tbody><tr><td> Nome del reagente </td><td> Azienda </td><td> Numero di catalogo </td></tr><tr><td> Di rame (II) solfato pentaidrato </td><td> Sigma-Aldrich </td><td> 203165 </td></tr><tr><td> Alexa Fluor 488 azide </td><td> Invitrogen </td><td> A10266 </td></tr><tr><td> destrano, Alexa Fluor 594 </td><td> Invitrogen </td><td> D-22913 </td></tr><tr><td> (+)-L-ascorbato di sodio </td><td> Sigma-Aldrich </td><td> A7631 </td></tr><tr><td> Bathocuproinedisulfonic acido </td><td> Acros Organics </td><td> 164060010 </td></tr><tr><td> Con fondo di vetro piatto micropozzetti </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

Glicani di imaging in vivo è stato recentemente attivato utilizzando un bioorthogonal strategia giornalista chimica trattando cellule o degli organismi con monosaccaridi azide-o alchini-tag 1, 2. Il monosaccaridi modificato, elaborato dalla macchina biosintetica glicani, sono incorporati in glicoconiugati superficie cellulare. I tag bioorthogonal azide o alchini quindi consentire coniugazione covalente con sonde fluorescenti per la visualizzazione, oppure con sonde affinità per l&#39;arricchimento e l&#39;analisi glycoproteomic. Questo protocollo descrive le procedure normalmente utilizzate per l&#39;imaging non invasivo di glicani fucosylated in embrioni di zebrafish, tra cui: 1) microiniezione di una cella-embrioni stadio con un PIL-5-alkynylfucose (PIL-FucAl), 2) l&#39;etichettatura glicani fucosylated nello strato avvolgente di embrioni di zebrafish con azide coniugato fluorofori via Cu biocompatibile (I)-catalizzata azide-alchino cicloaddizione (CuAAC), e 3) l&#39;imaging mediante microscopia confocale 3. Il metodo descritto qui può essere facilmente esteso ad altre classi di visualizzare glicani, glicani contenenti ad esempio acido sialico 4 e N-acetilgalattosamina 5, 6, in zebrafish di sviluppo e in altri organismi viventi.

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

Un click-chimica metodo basato che permette la rapida, etichettatura non invasivo, e robusto di alchini-tagged glicani in embrioni di zebrafish è descritto. Glicani Fucosylated nello strato avvolgente di embrioni di zebrafish in fase di gastrulazione fine erano ripreso in questo studio.

Glicani Imaging in embrioni di zebrafish con marcatura metabolica e Chimica Clicca Bioorthogonal

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

13.6K Views.  Albert Einstein College of Medicine, Yeshiva University. Un click-chimica metodo basato che permette la rapida, etichettatura non invasivo, e robusto di alchini-tagged glicani in embrioni di zebrafish è descritto. Glicani Fucosylated nello strato avvolgente di embrioni di zebrafish in fase di gastrulazione fine erano ripreso in questo studio.

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

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.

Due fotoni assotomia e time-lapse confocale in embrioni di zebrafish vivo

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

Ricerca

Biologia

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.

Generare embrioni di zebrafish Chimerico da trapianto

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 ...

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 Forma Modifica cella in Living Drosophila Embrioni

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.

Cella di misura Kinetics progressione del ciclo con la marcatura metabolica e citometria a flusso

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.

Analisi Profilo metabolico di embrioni di zebrafish

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

Metabolic Labeling of Leucine Rich Repeat Kinases 1 and 2 with Radioactive Phosphate

Leucine rich repeat kinases 1 and 2 (LRRK1 and LRRK2) are paralogs which share a similar domain organization, including a serine-threonine kinase domain, a Ras of complex proteins domain (ROC), a C-terminal of ROC domain (COR), and leucine-rich and ankyrin-like repeats at the N-terminus. The precise cellular roles of LRRK1 and LRRK2 have yet to be elucidated, however LRRK1 has been implicated in tyrosine kinase receptor signaling1,2, while LRRK2 is implicated in the pathogenesis of Parkinson's disease3,4. In this report, we present a protocol to label the LRRK1 and LRRK2 proteins in cells with 32P orthophosphate, thereby providing a means to measure the overall phosphorylation levels of these 2 proteins in cells. In brief, affinity tagged LRRK proteins are expressed in HEK293T cells which are exposed to medium containing 32P-orthophosphate. The 32P-orthophosphate is assimilated by the cells after only a few hours of incubation and all molecules in the cell containing phosphates are thereby radioactively labeled. Via the affinity tag (3xflag) the LRRK proteins are isolated from other cellular components by immunoprecipitation. Immunoprecipitates are then separated via SDS-PAGE, blotted to PVDF membranes and analysis of the incorporated phosphates is performed by autoradiography (32P signal) and western detection (protein signal) of the proteins on the blots. The protocol can readily be adapted to monitor phosphorylation of any other protein that can be expressed in cells and isolated by immunoprecipitation.

Leucine rich repeat kinases 1 and 2 (LRRK1 and LRRK2) are multidomain proteins which encode both GTPase and kinase domains and which are phosphorylated in cells. Here, we present a protocol to label LRRK1 and LRRK2 in cells with 32P orthophosphate, thereby providing a means to measure their overall cellular phophorylation levels.

Metabolica Etichettatura di leucina Rich Repeat chinasi 1 e 2 con Radioactive fosfato

Leucine rich repeat kinases 1 and 2 (LRRK1 and LRRK2) are paralogs which share a similar domain organization, including a serine-threonine kinase domain, ...

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.

Analisi dello Stress Ossidativo in embrioni di zebrafish

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.

Imaging semi-automatico di fluorescenza tessuto-specifica in embrioni di zebrafish

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

Measurement of Metabolic Rate in Drosophila using Respirometry

Metabolic disorders are a frequent problem affecting human health. Therefore, understanding the mechanisms that regulate metabolism is a crucial scientific task. Many disease causing genes in humans have a fly homologue, making Drosophila a good model to study signaling pathways involved in the development of different disorders. Additionally, the tractability of Drosophila simplifies genetic screens to aid in identifying novel therapeutic targets that may regulate metabolism. In order to perform such a screen a simple and fast method to identify changes in the metabolic state of flies is necessary. In general, carbon dioxide production is a good indicator of substrate oxidation and energy expenditure providing information about metabolic state. In this protocol we introduce a simple method to measure CO2 output from flies. This technique can potentially aid in the identification of genetic perturbations affecting metabolic rate.

Measurement of Metabolic Rate in Drosophila using Respirometry

Metabolic disorders are among one of the most common diseases in humans. The genetically tractable model organism D. melanogaster can be used to identify novel genes that regulate metabolism. This paper describes a relatively simple method which allows studying the metabolic rate in flies by measuring their CO2 production.

Misurazione del tasso metabolico in<em&gt; Drosophila</em&gt; Utilizzando respirometria

Metabolic disorders are a frequent problem affecting human health. Therefore, understanding the mechanisms that regulate metabolism is a crucial ...

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) maintain the turnover of all mature blood cell lineages. The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood[1-2].
We describe how by combining a newly developed specimen holder for stable animal positioning with multi-step confocal and two-photon in vivo imaging techniques, it is possible to obtain high-resolution 3D stacks containing HSPCs and their surrounding niches and to monitor them over time through multi-point time-lapse imaging. High definition imaging allows detecting ex vivo labeled hematopoietic stem and progenitor cells (HSPCs) residing within the bone marrow. Moreover, multi-point time-lapse 3D imaging, obtained with faster acquisition settings, provides accurate information about HSPC movement and the reciprocal interactions between HSPCs and stroma cells.
Tracking of HSPCs in relation to GFP positive osteoblastic cells is shown as an exemplary application of this method. This technique can be utilized to track any appropriately labeled hematopoietic or stromal cell of interest within the mouse calvarium bone marrow space.

In Vivo 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

The nature of the interactions between hematopoietic stem and progenitor cells (HSPCs) and bone marrow niches is poorly understood. Custom hardware modifications and a multi-step acquisition protocol allow the use of two-photon and confocal microscopy to image ex vivo labeled HSPCs homed within bone marrow areas, tracking interactions and movement.

In Vivo inseguimento 4-dimensionale di emopoietiche staminali e progenitrici celle di topo adulto cranica di Midollo Osseo

Through a delicate balance between quiescence and proliferation, self renewal and production of differentiated progeny, hematopoietic stem cells (HSCs) ...