DP é destinatário de Ruth Award Kirschstein DA021977 1F32-01A1 do Instituto Nacional sobre Abuso de Drogas. Este trabalho foi financiado pela M. Margaret Alkek Fundação RHF.

<html> I. Visão geral esquemática: <img src="/files/ftp_upload/old/1027_2009_1_22_2/Figure1.png" alt="Figura 1" width="460" height="384" /> Este vídeo demonstra as diferentes etapas no ensaio para a indução neural no embrião de galinha. Primeiro, o embrião hospedeiro é explantado na cultura New [NI1]. Então, o embrião é Donnor explantado em solução salina e do nó de Hensen (o &quot;organizador&quot; no bico) é marcado com corante fluorescente DII [NI2]. Nó de Hensen é retirado do embrião Donnor [NI3] e transplantadas para o embrião hospedeiro [NI4, NI5]. O embrião hospedeiro é então cultivadas por até 22 horas, período após o qual o tecido Donnor induziu um eixo ectópica na área de acolhimento opaca [NI6]. Após a cultura, o embrião hospedeiro é fixo e processados ​​para fotooxidação na presença de DAB: Por esta reação química, as células derivadas Donnor, que aparecem em vermelho sob fluorescência FITC antes fotooxidação [NI7], tornar-se seguinte reação marrom com DAB [NI8]. O embrião é então processada por hibridização in situ com um marcador neural [NI8]; tecido hospedeiro derivados formou tecido neural na presença do enxerto Donnor. Este tecido aparece em azul. 1: Preparando o embrião hospedeiro para a cultura de Nova <ol><li> Este protocolo de ensaio de indução neural começa com os ovos que foram incubados a Hamburger &amp; Hamilton estágio 3 + (ou hh3 +). Estes ovos foram incubados estabelecidas em seu lado em uma incubadora úmida por 13 horas. </li><li> Prepare o embrião hospedeiro para a cultura Novo (passos 3.1. A 5.5 9). </li><li> Cubra a superfície do embrião hospedeiro com 200 mL solução salina. Isto irá facilitar a transferência mais tarde e posicionamento do enxerto Donnor. </li><li> Finalmente, cobrir o conjunto com uma placa de cultura invertida Falcon 35 mm. </li></ol> 2: Explanting o embrião Donnor em solução salina <ol><li> Abra o ovo batendo na casca com uma pinça e retirar pedaços da casca, em todo o shell. Remover topo da casca e descarte. </li><li> Remova a albumina espessa com uma pinça, e incline o saco vitelino com uma pinça grossa para que o embrião voltado para cima. </li><li> Com uma tesoura fina, corte um quadrado de saco vitelino em torno do embrião. Remover o embrião da gema com uma colher e coloque em um prato contendo PBS. </li><li> Utilizando uma pinça, retire o embrião Donnor da área pelúcida. </li><li> Transferência de embriões Donnor a um prato coberto Sylgard contendo PBS. </li></ol> 3: Rotulagem, excisão e transplante de enxerto Donnor <ol><li> Utilizando um extrator de microeletrodos, puxar 50 pipetas de vidro mL microcapilar. Sob o microscópio, corte a ponta da micropipeta usando uma pinça fina. Micropipeta lugar numa placa de Petri forrada com uma fita de plasteline. </li><li> Preparar a solução corante que será usado para rotular o enxerto antes do transplante: DII carbocyanine corante (1,1 &#39;-dioctadecyl-3, 3,3&#39;, 3&#39;-tetramethylindocarbocyanine perclorato): Primeiro, prepare um estoque de DII em 1ml etanol absoluto em 0,5%. Este material pode ser armazenado a-20C no escuro. Em um banho-maria regulado a 42 ° C, pré-aquecido 40 mix de ações DII mL de 360μl sacarose 0.3M. A temperatura do banho de água é necessário para evitar a precipitação de DII e formação de cristais insolúveis. Brevemente girar a solução em um Spectrafuge mini (por 5-10 segundos). A solução DII está pronto para usar. </li><li> Utilizando os pinos de insetos, segura o embrião Donnor no fundo do prato Sylgard coberto. </li><li> Back-preencher a micropipeta com DII. Aplicando uma pressão suave usando um conjunto de tubos de aspiração, aplicar um bolo pequeno de DII para o nó de Hensen. Certifique-se o nó de Hensen inteiro é rotulado. </li><li> Com uma pipeta microcapilar ou uma faca microdissecting, corte do nó de Hensen (&quot;organizador&quot;, enxerto Donnor). </li><li> Marcar o lado ventral e extremidade posterior do enxerto com carmim. Isso irá garantir que o enxerto é posicionado com a orientação dorso-ventral apropriada no passo 4.3. </li><li> Usando um 200μl Gilson pipeta, transferir o enxerto para o embrião hospedeiro. </li></ol> 4: Protegendo o enxerto e de cultura do embrião hospedeiro <ol><li> Remover salina de embrião hospedeiro, certificando-se o enxerto permanece posicionada na proximidade com o local host. </li><li> Com uma pipeta microcapilar ou uma faca microdissecting, fazer uma pequena incisão (80-100μm) na área pelúcida / área opaca região de fronteira, ao nível do nó de Hensen embrião hospedeiro. </li><li> Utilizando uma pipeta ou uma microcapilar microdissecting faca posição, o enxerto para que lado ventral voltado para você e na extremidade posterior é paralela à região equivalente em embrião hospedeiro. </li><li> Remover salina restantes, e processar o embrião hospedeiro para nova cultura de 81-22 hr (passos 6,1-6,6 9). </li><li> O embrião hospedeiro é então fixado durante a noite a 4 ° C (7,1-7,7 passos 9). </li></ol>e &quot;&gt; 5: Photooxidise o enxerto sob fluorescência <ol><li> De acordo com exaustor, preparar uma solução DAB trabalhando em tampão Tris: Dissolver substrato DAB (3,3 tetrahidrocloreto &#39;diaminobenzidina) em tampão Tris (100mM Tris-HCl, pH 7,4) em 500μg/ml; manter solução no escuro, sobre o gelo. </li><li> Lavar o embrião duas vezes em PBS por 5 min cada um e de vez em tampão Tris durante 5 mn. </li><li> Transferência do embrião para uma lâmina de vidro contendo uma cavidade ml de tampão Tris. </li><li> Substituir a solução tampão Tris com 1,5 ml solução DAB. Dispor de Eppendorf ponta em balde contendo uma solução de lixívia a 10%, a fim de descontaminar DAB. Coloque uma lamela em cima do deslize da cavidade. </li><li> De acordo com FITC fluorescência (isotiocianato de fluoresceína), o foco do objetivo do microscópio sobre o enxerto (células Donnor aparecerá vermelha fluorescente) e expor a fluorescência FITC até todas as células fluorescentes vermelhas tornaram-se marrom (isso acontece como resultado da DII fluorocromo sendo photoconverted a insolúvel cristais marrom, pela exposição ao comprimento de onda de excitação FITC (488nm) na presença de DAB. Este processo leva entre 20 minutos e 2 horas. </li><li> Após a conclusão da reação de fotooxidação, retire a lamínula usando uma pinça fina. Transferência de embriões para um frasco de vidro de cintilação contendo 20 ml PBTw (ou PBS com 0,1% Tween-20). </li><li> Desativar DAB de lamela e deslize cavidade de vidro através da incubação em solução de água sanitária a 10%. </li></ol> 6: Processo para o embrião in situ hybridization, fotografia e corte <ol><li> Prosseguir com a hibridização in situ (passos 3,7-6,5 9), incubando o embrião para somente DIG sonda marcada. </li><li> Prosseguir com a fotografar (passo 8,2 9) e secção (passos 8.3 e 8.4 9). </li></ol> Resultados representante No exemplo a seguir de ensaio a indução neural, o enxerto Donnor é mostrado induzir a expressão do marcador neural sem cauda de tecido do hospedeiro derivadas. Neste exemplo em particular, foi avaliada a aquisição de capacidade de indução neural das regiões embrionárias que normalmente não têm &quot;organizer&quot; habilidades: o enxerto Donnor origina de um embrião em que o &quot;organizador&quot; da região foi removido cirurgicamente do embrião na fase Donnor 3 +. Após a ablação, o embrião Donnor é permitido desenvolver-se em nova cultura, até que o buraco tem curado e uma estrutura semelhante a do nó de Hensen formou. Esta estrutura é, então, marcado com DII, retirado do embrião Donnor e enxertadas para a área de fronteira opaca pelúcida / área de um embrião hospedeiro. Após nova cultura, um eixo em miniatura é formado adjacente ao embrião hospedeiro: este eixo miniatura consiste de uma haste de glóbulos vermelhos (Donnor derivados) e uma estrutura de cabeça-like (host derivados): Em (A), Donnor derivados DII rotulados células são mostrados antes da fixação sob microscopia de fluorescência FITC. Estas células Donnor derivados têm proliferado para formar uma notocorda em miniatura, que aparece como vara de glóbulos vermelhos. (B) fotoconversão Depois de DII, essas células Donnor derivados aparecem marrom. O enxerto Donnor induziu a formação de tecido neural a partir do host: este tecido consiste de precursores para o cérebro, como revelado pela sua expressão para o seguinte marcador sem cauda de hibridização in situ [reimpressão da 6]. <img src="/files/ftp_upload/old/1027_2009_1_22_3/Figure 2.png" alt="figura 2" width="230" height="154" /> Nota: Neste procedimento, usamos células DII rotulados, a fim de diferenciar tecido neural induzindo Donnor (vermelho / marrom) do host derivadas de tecido &quot;neural&quot; (azul). Em vez de usar uma garota derivada, DII enxerto Donnor rotulados, alguns autores também utilizam Donnor tecido derivadas de embriões de codorna, em vez de pinto [eg 6]. Este método alternativo também permite diferenciar Donnor do tecido hospedeiro. Neste caso, o enxerto (tecido Donnor) se origina a partir de ovos de codorna, em vez de ovos de galinha. Seguinte passo 4.5, o host é processado para imunohistoquímica montagem inteira com um anticorpo específico para codorna tecido (QCP1) e as etapas 3,1-3,4 e 5,1-5,7 são omitidos do protocolo. Um exemplo deste procedimento alternativo é mostrado abaixo: Nesse caso, usamos o mesmo procedimento experimental como em A, B, mas nós usamos codorna derivadas do tecido Donnor (como mostrado pela expressão de anticorpos QCPN [marrom]): O regenerado nó derivado de embrião de codorna tem induzido a expressão de pan-neural marcador Sox2 no hospedeiro [reimpresso de 6]: <img src="/files/ftp_upload/old/1027_2009_1_22_4/Figure 3.png" alt="Figura 3" width="154" height="230" />

<ol>
	<li>Waddington, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experiments+on+the+development+of+chick+and+duck+embryos,+cultivated+in+vitro.">Experiments on the development of chick and duck embryos, cultivated in vitro.</a> Phil. Trans. R. Soc. Lond. B. 221, 179-230 (1932).</li><li>Waddington, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+by+the+primitive+streak+and+its+derivatives+in+the+chick.">Induction by the primitive streak and its derivatives in the chick.</a> J. Exp. Biol. 10, 38-46 (1933).</li><li>Gallera, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excision+et+transplantation+des+diff&amp;eacute;rentes+r&amp;eacute;gions+de+la+ligne+primitive+chez+le+poulet.">Excision et transplantation des diff&amp;eacute;rentes r&amp;eacute;gions de la ligne primitive chez le poulet.</a> C. R. Ass. Anat. 49, 632-639 (1964).</li><li>Gallera, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+induction+in+birds.">Primary induction in birds.</a> Adv. Morph. 9. , 149-180 (1971).</li><li>Serbedzija, G. N., Fraser, S. E., Bronner-Fraser, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathways+of+neural+crest+cell+migration+in+the+mouse+embryo+as+revealed+by+vital+dye+labeling.+Development+108.">Pathways of neural crest cell migration in the mouse embryo as revealed by vital dye labeling. Development 108.</a> , 605-612 (1990).</li><li>Psychoyos, D., Stern, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Restoration+of+the+organizer+after+radical+ablation+of+Hensen's+node+and+the+anterior+primitive+streak+in+the+chick+embryo.+Development+122.">Restoration of the organizer after radical ablation of Hensen's node and the anterior primitive streak in the chick embryo. Development 122.</a> , 3263-3273 (1996).</li><li>Joubin, K., Stern, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+interactions+continuously+define+the+organizer+during+the+cell+movements+of+gastrulation.">Molecular interactions continuously define the organizer during the cell movements of gastrulation.</a> Cell. 98, 559-571 (1999).</li><li>Streit, A., Berliner, A. J., Papanayotou, C., Sirulnik, A., Stern, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Initiation+of+neural+induction+by+FGF+signaling+before+gastrulation.">Initiation of neural induction by FGF signaling before gastrulation.</a> Nature. , 406-474 (2000).</li><li>Psychoyos, D., Finnell, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+for+Culture+of+Early+Chick+Embryos+ex+vivo+(New+Culture.">Method for Culture of Early Chick Embryos ex vivo (New Culture.</a> JoVE. 20, 10-3791 (2008).</li></ol>

Este vídeo demonstra as diferentes etapas na realização de um ensaio para a indução neural; Este ensaio é essencialmente usado para a caracterização da suposta indução neural em moléculas de bico, e, portanto, pode ser usado para uma ampla variedade de aplicações, que vão desde micromanipulations embriológico 1-4; 6 a desvendar novas cascatas de sinalização 7,8, todas visando a compreensão da etapa inicial na formação do cérebro e restante do sistema nervoso.

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Eggs</td>
<td>Animal</td>
<td>Charles River Laboratories</td>
<td>Premium Fertile</td>
<td>Fertilized, HH3+ (14 hr)</td>
</tr>
<tr>
<td>Stereomicroscope</td>
<td>Microscope</td>
<td>Leica Microsystems</td>
<td>MZ9.5 or similar</td>
<td>&nbsp;</td>
<tr>
<td>Hybridization Incubator</td>
<td>Equipment</td>
<td>Robbins Scientific</td>
<td>M1000</td>
<td>Use with inverted Pyrex dish and 500 ml ddH2O beaker</td>
</tr>
<tr>
<td>Marsh Automatic Incubator</td>
<td>Equipment</td>
<td>Lyon</td>
<td>RX</td>
<td>&nbsp;</td>
<tr>
<td>Pyrex dish </td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Watchmaker's glass 50mm</td>
<td>Tool</td>
<td>VWR</td>
<td>66112-060</td>
<td>&nbsp;</td>
<tr>
<td>Glass rings</td>
<td>Tool</td>
<td>Physical Plant facility</td>
<td>&nbsp;</td>
<td>cut 4 mm thick sections of glass tubing (27 mm outer diam, 25 mm inner diam). Do not fine polish.</td>
</tr>
<tr>
<td>Curved Forceps (1)</td>
<td>Tool</td>
<td>Electron Microscopy Sciences</td>
<td>72991-4C</td>
<td>&nbsp;</td>
<tr>
<td>Forceps (2)</td>
<td>Tool</td>
<td>Fine Science Tools</td>
<td>11002-13</td>
<td>blunt ended using sharpening Stone and 100ul mineral oil</td>
</tr>
<tr>
<td>Fine scissors</td>
<td>Tool</td>
<td>Fine Science Tools</td>
<td>14161-10</td>
<td>&nbsp;</td>
<tr>
<td>Plastic dishes</td>
<td>Tool</td>
<td>Falcon</td>
<td>353001</td>
<td>&nbsp;</td>
<tr>
<td>Rubber Bulb</td>
<td>Tool</td>
<td>Electron Microscopy Sciences</td>
<td>70980</td>
<td>&nbsp;</td>
<tr>
<td>DiI</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>D-282</td>
<td>&nbsp;</td>
<tr>
<td>Aspirator tube assembly</td>
<td>Tool</td>
<td>Sigma</td>
<td>A5177-5EA</td>
<td>&nbsp;</td>
<tr>
<td>Microelectrode puller</td>
<td>Equipment</td>
<td>Sutter Instruments</td>
<td>Sutter Instruments	P-97 Flaming/Brown Micropipette</td>
<td>&nbsp;</td>
<tr>
<td>Pasteur Capillary Pipette</td>
<td>Tool</td>
<td>Electron Microscopy Sciences</td>
<td>70950-12</td>
<td>round edge under flame</td>
</tr>
<tr>
<td>Culture chamber</td>
<td>Tool</td>
<td>Pioneer Plastics</td>
<td>030C</td>
<td>&nbsp;</td>
<tr>
<td>Microcapillary tube</td>
<td>Tool</td>
<td>Sigma</td>
<td>P1049-1PAK</td>
<td>&nbsp;</td>
<tr>
<td>Microdissecting knife</td>
<td>Tool</td>
<td>Fine Science Tools</td>
<td>10056-12</td>
<td>Use to puncture cavities prior to in situ hybridization</td>
</tr>
<tr>
<td>Minuten pins 0.2mm diam</td>
<td>Tool</td>
<td>Fine Science Tools</td>
<td>26002-20</td>
<td>Mix 1 part Curing Agent, 9 parts Base; set O/N at 37C</td>
</tr>
<tr>
<td>Diethylpyrocarbonate (depc)</td>
<td>Reagent</td>
<td>Electron Microscopy Sciences</td>
<td>15710</td>
<td>&nbsp;</td>
<tr>
<td>Sylgard 184 Silicon Elastomer Curing Agent and Base</td>
<td>&nbsp;</td>
<td>Dow Corning</td>
<td>0001986475</td>
<td>Mix 1 part Curing Agent, 9 parts Base; set O/N at 37C</td>
</tr>
<tr>
<td>Diethylpyrocarbonate (depc)</td>
<td>&nbsp;</td>
<td>Acros Organics</td>
<td>10025025</td>
<td>Add 1ml depc to 1l PBS; shake; autoclave</td>
</tr>
<tr>
<td>16% PFA</td>
<td>&nbsp;</td>
<td>Electron Microscopy Sciences</td>
<td>15710</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

assay for neural induction in the chick embryo

O embrião de galinha é uma ferramenta valiosa no estudo do desenvolvimento embrionário precoce. Sua transparência, acessibilidade e facilidade de manipulação, torná-lo uma ferramenta ideal para estudar a formação inicial e padronização do sistema nervoso. Este vídeo demonstra como organizador do enxerto de tecido em um host, um método pelo qual nó s Hensen (o organizador do embrião de galinha) é enxertado em um ectoderma competente de acolhimento. O enxerto organizador instrui sobrejacente nd ve tecido de adotar um destino através de sinais neurais indução neural. Esse mecanismo é conhecido como indução neural, e constitui o passo inicial na formação do cérebro e da medula espinhal em amniotas. Este método é essencialmente utilizado para a caracterização de moléculas indução neural putativo no pinto. Este vídeo demonstra as diferentes etapas no ensaio para a indução neural; Primeiro, o embrião é Donnor explantado e colocou em um prato. Então, o embrião hospedeiro está preparado para a nova cultura. O enxerto é retirado e transplantado para o host margem área pelúcida. O host é cultivado para 18-22 hrs. A montagem é fixa e processados ​​para outras aplicações (por exemplo, hibridização in situ). Este método foi originalmente concebido por Waddington<sup&gt; 1,2</sup&gt; E Gallera<sup&gt; 3,4</sup&gt;.

Watch this Scientific Journal Video about Assay for Neural Induction in the Chick Embryo at JoVE.com

Assay for Neural Induction in the Chick Embryo

Indução neural é o primeiro passo na formação do cérebro. É um mecanismo pelo qual o nó de Hensen (organizador), instrui tecido adjacente a adotar um destino neural, ou seja, dar origem ao sistema nervoso. Este vídeo demonstra um ensaio para a indução neural no embrião de galinha.

Ensaio para Indução Neural no embrião de galinha

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ...

assay-for-neural-induction-in-the-chick-embryo

Research

JoVE Journal

Biology

17.1K visualizações.  Texas A&M University (TAMU). Indução neural é o primeiro passo na formação do cérebro. É um mecanismo pelo qual o nó de Hensen (organizador), instrui tecido adjacente a adotar um destino neural, ou seja, dar origem ao sistema nervoso. Este vídeo demonstra um ensaio para a indução neural no embrião de galinha.

Vídeo: Assay for Neural Induction in the Chick Embryo

Double Whole Mount in situ Hybridization of Early Chick Embryos

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying  gene expression in brain, neural tube, somite and heart primordia formation. This video demonstrates the different steps in 2-color whole mount in situ hybridization; First, the embryo is dissected from the egg and fixed in paraformaldehyde. Second, the embryo is processed for prehybridization. The embryo is then hybridized with two different probes, one coupled to DIG, and one coupled to FITC.  Following overnight hybridization, the embryo is incubated with DIG coupled antibody. Color reaction for DIG substrate is performed, and the region of interest appears blue. The embryo is then incubated with FITC coupled antibody. The embryo is processed for color reaction with FITC, and the region of interest appears red. Finally, the embryo is fixed and processed for phtograph and sectioning. A troubleshooting guide is also presented.

This video demonstrates 2-color whole mount in situ hybridization, a method by which the spatial and temporal expression pattern of 2 different genes can be visualized in young chick embryos. This method was originally introduced by David Wilkinson, Domingos Henrique, Phil Ingham and David Ish -Horowicz.

Monte Whole dupla hibridização in situ de embriões de galinha precoce

Biologia

Method for Whole Mount Antibody Staining in Chick

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying antibody expression in developing brain, neural tube and somite. This video demonstrates the different steps in whole-mount antibody staining using HRP conjugated secondary antibodies; First, the embryo is dissected from the egg and fixed in paraformaldehyde. Second, endogenous peroxidase is inactivated; The embryo is then exposed to primary antibody. After several washes, the embryo is incubated with secondary antibody conjugated to HRP. Peroxidase activity is revealed using reaction with diaminobenzidine substrate. Finally, the embryo is fixed and processed for photography and sectioning. The advantage of this method over the use of fluorescent antibodies is that embryos can be processed for wax sectioning, thus enabling the study of antigen sites in cross section. This method was originally introduced by Jane Dodd and Tom Jessell 1.

This video demonstrates whole mount immunohistochemistry, a method by which the spatial and temporal expression pattern of an antigen can be visualized in young chick embryos. This method was originally introduced by Jane Dodd and Tom Jessell.

Método para coloração Whole Mount anticorpos em Pintainho

Electrophysiological Recording in the Drosophila Embryo

Drosophila is a premier genetic model for the study of both embryonic development and functional neuroscience. Traditionally, these fields are quite isolated from each other, with largely independent histories and scientific communities. However, the interface between these usually disparate fields is the developmental programs underlying acquisition of functional electrical signaling properties and differentiation of functional chemical synapses during the final phases of neural circuit formation. This interface is a critically important area for investigation. In Drosophila, these phases of functional development occur during a period of &lt;8 hours (at 25&deg;C) during the last third of embryogenesis. This late developmental period was long considered intractable to investigation owing to the deposition of a tough, impermeable epidermal cuticle. A breakthrough advance was the application of water-polymerizing surgical glue that can be locally applied to the cuticle to enable controlled dissection of late-stage embryos. With a dorsal longitudinal incision, the embryo can be laid flat, exposing the ventral nerve cord and body wall musculature to experimental investigation. Whole-cell patch-clamp techniques can then be employed to record from individually-identifiable neurons and somatic muscles. These recording configurations have been used to track the appearance and maturation of ionic currents and action potential propagation in both neurons and muscles. Genetic mutants affecting these electrical properties have been characterized to reveal the molecular composition of ion channels and associated signaling complexes, and to begin exploration of the molecular mechanisms of functional differentiation. A particular focus has been the assembly of synaptic connections, both in the central nervous system and periphery. The glutamatergic neuromuscular junction (NMJ) is most accessible to a combination of optical imaging and electrophysiological recording. A glass suction electrode is used to stimulate the peripheral nerve, with excitatory junction current (EJC) recordings made in the voltage-clamped muscle. This recording configuration has been used to chart the functional differentiation of the synapse, and track the appearance and maturation of presynaptic glutamate release properties. In addition, postsynaptic properties can be assayed independently via iontophoretic or pressure application of glutamate directly to the muscle surface, to measure the appearance and maturation of the glutamate receptor fields. Thus, both pre- and postsynaptic elements can be monitored separately or in combination during embryonic synaptogenesis. This system has been heavily used to isolate and characterize genetic mutants that impair embryonic synapse formation, and thus reveal the molecular mechanisms governing the specification and differentiation of synapse connections and functional synaptic signaling properties.

Electrophysiological Recording in the Drosophila Embryo

Electrophysiological recordings from Drosophila embryos allow analyses of developing muscle and neuron electrical properties, as well as characterization of functional synaptogenesis at the glutamatergic neuromuscular junction and central cholinergic and GABAergic synapses.

Gravação eletrofisiológicas na Drosophila Embrião

Drosophila is a premier genetic model for the study of both embryonic development and functional neuroscience. Traditionally, these fields are quite ...

Microinjection Techniques for Studying Mitosis in the Drosophila melanogaster Syncytial Embryo

This protocol describes the use of the Drosophila melanogaster syncytial embryo for studying mitosis1. Drosophila has useful genetics with a sequenced genome, and it can be easily maintained and manipulated. Many mitotic mutants exist, and transgenic flies expressing functional fluorescently (e.g. GFP) - tagged mitotic proteins have been and are being generated. Targeted gene expression is possible using the GAL4/UAS system2. 

The Drosophila early embryo carries out multiple mitoses very rapidly (cell cycle duration, &asymp;10 min). It is well suited for imaging mitosis, because during cycles 10-13, nuclei divide rapidly and synchronously without intervening cytokinesis at the surface of the embryo in a single monolayer just underneath the cortex. These rapidly dividing nuclei probably use the same mitotic machinery as other cells, but they are optimized for speed; the checkpoint is generally believed to not be stringent, allowing the study of mitotic proteins whose absence would cause cell cycle arrest in cells with a strong checkpoint. Embryos expressing GFP labeled proteins or microinjected with fluorescently labeled proteins can be easily imaged to follow live dynamics (Fig. 1). In addition, embryos can be microinjected with function-blocking antibodies or inhibitors of specific proteins to study the effect of the loss or perturbation of their function3. These reagents can diffuse throughout the embryo, reaching many spindles to produce a gradient of concentration of inhibitor, which in turn results in a gradient of defects comparable to an allelic series of mutants. Ideally, if the target protein is fluorescently labeled, the gradient of inhibition can be directly visualized4. It is assumed that the strongest phenotype is comparable to the null phenotype, although it is hard to formally exclude the possibility that the antibodies may have dominant effects in rare instances, so rigorous controls and cautious interpretation must be applied. Further away from the injection site, protein function is only partially lost allowing other functions of the target protein to become evident.

Microinjection Techniques for Studying Mitosis in the Drosophila melanogaster Syncytial Embryo

This protocol describes the use of microinjection and high resolution imaging in the Drosophila melanogaster syncytial embryo to study mitosis.

Técnicas de microinjeção para estudar na Mitose Drosophila melanogaster Embrião Sincicial

This protocol describes the use of the Drosophila melanogaster syncytial embryo  for studying mitosis1.  Drosophila has useful genetics with a sequenced ...

Chick ex ovo Culture and ex ovo CAM Assay: How it Really Works

Chicken eggs in the early phase of breeding are between in vitro and in vivo systems and provide a vascular test environment not only to study angiogenesis but also to study tumorigenesis. After the chick chorioallantoic membrane (CAM) has developed, its blood vessel network can be easily accessed, manipulated and observed and therefore provides an optimal setting for angiogenesis assays. Since the lymphoid system is not fully developed until late stages of incubation, the chick embryo serves as a naturally immunodeficient host capable of sustaining grafted tissues and cells without species-specific restrictions. In addition to nurturing developing allo- and xenografts, the CAM blood vessel network provides a uniquely supportive environment for tumor cell intravasation, dissemination, and vascular arrest and a repository where arrested cells extravasate to form micro metastatic foci.
For experimental purposes, in most of the recent studies the CAM was exposed by cutting a window through the egg shell and experiments were carried out in ovo, resulting in significant limitations in the accessibility of the CAM and possibilities for observation and photo documentation of effects. When shell-less cultures of the chick embryo were used1-4, no experimental details were provided and, if published at all, the survival rates of these cultures were low. We refined the method of ex ovo culture of chick embryos significantly by introducing a rationally controlled extrusion of the egg content. These ex ovo cultures enhance the accessibility of the CAM and chick embryo, enabling easy in vivo documentation of effects and facilitating experimental manipulation of the embryo. This allows the successful application to a large number of scientific questions: (1) As an improved angiogenesis assay5,6, (2) an experimental set up for facilitated injections in the vitreous of the chick embryo eye7-9, (3) as a test environment for dissemination and intravasation of dispersed tumor cells from established cell lines inoculated on the CAM10-12, (4) as an improved sustaining system for successful transplantation and culture of limb buds of chicken and mice13 as well as (5) for grafting, propagation, and re-grafting of solid primary tumor tissue obtained from biopsies on the surface of the CAM14.
In this video article we describe the establishment of a refined chick ex ovo culture and CAM assay with survival rates over 50%. Besides we provide a step by step demonstration of the successful application of the ex ovo culture for a large number of scientific applications. 
Daniel S. Dohle, Susanne D. Pasa, and Sebastian Gustmann contributed equally to this study.

Chick ex ovo Culture and ex ovo CAM Assay: How it Really Works

The chick chorioallantoic membrane (CAM) is a unique, naturally immunodeficient supportive culture environment to study angiogenesis and tumorigenesis. This video article demonstrates the different steps in chick ex ovo culture, application of potentially angiogenic substances and successful inoculation of tumor cells and tissues on the surface of the CAM.

Pintinho Ex ovo Cultura e Ex ovo CAM Ensaio: como ele realmente funciona

Chicken eggs in the early phase of breeding are between in vitro and in vivo systems and provide a vascular test environment not only to study ...

Deciphering Axonal Pathways of Genetically Defined Groups of Neurons in the Chick Neural Tube Utilizing in ovo Electroporation

Employment of enhancer elements to drive expression of reporter genes in neurons is a widely used paradigm for tracking axonal projection. For tracking axonal projection of spinal interneurons in vertebrates, germ line-targeted reporter genes yield bilaterally symmetric labeling. Therefore, it is hard to distinguish between the ipsi- and contra-laterally projecting axons. Unilateral electroporation into the chick neural tube provides a useful means to restrict expression of a reporter gene to one side of the central nervous system, and to follow axonal projection on both sides 1 ,2-5. This video demonstrates first how to handle the eggs prior to injection. At HH stage 18-20, DNA is injected into the sacral level of the neural tube, then tungsten electrodes are placed parallel to the embryo and short electrical pulses are administered with a pulse generator. The egg is sealed with tape and placed back into an incubator for further development. Three days later (E6) the spinal cord is removed as an open book preparation from embryo, fixed, and processed for whole mount antibody staining. The stained spinal cord is mounted on slide and visualized using confocal microscopy.

Deciphering Axonal Pathways of Genetically Defined Groups of Neurons in the Chick Neural Tube Utilizing in ovo Electroporation

This video demonstrates how to visualize axonal pathways of genetically defined groups of neurons in the embryonic chick spinal cord utilizing in ovo electroporation of reporter genes under the control of specific enhancer elements.

Decifrando Pathways Axonal dos Grupos geneticamente definidos de neurônios no tubo Neural Utilizando Pintainho In ovo Eletroporação

Employment of enhancer elements to drive expression of reporter genes in neurons is a widely used paradigm for tracking axonal projection. For tracking ...

Xenotransplantation of Human Stem Cells into the Chicken Embryo

The chicken embryo is a classical animal model for studying normal embryonic and fetal development and for xenotransplantation experiments to study the behavior of cells in a standardized in vivo environment. The main advantages of the chicken embryo include low cost, high accessibility, ease of surgical manipulation and lack of a fully developed immune system. Xenotransplantation into chicken embryos can provide valuable information about cell proliferation, differentiation and behavior, the responses of cells to signals in defined embryonic tissue niches, and tumorigenic potential. Transplanting cells into chicken embryos can also be a step towards transplantation experiments in other animal models. Recently the chicken embryo has been used to evaluate the neurogenic potential of human stem and progenitor cells following implantation into neural anlage1-6. In this video we document the entire procedure for transplanting human stem cells into the developing central nervous system of the chicken embryo. The procedure starts with incubation of fertilized eggs until embryos of the desired age have developed. The eggshell is then opened, and the embryo contrasted by injecting dye between the embryo and the yolk. Small lesions are made in the neural tube using microsurgery, creating a regenerative site for cell deposition that promotes subsequent integration into the host tissue. We demonstrate injections of human stem cells into such lesions made in the part of the neural tube that forms the hindbrain and the spinal cord, and into the lumen of the part of the neural tube that forms the brain. Systemic injections into extraembryonic veins and arteries are also demonstrated as an alternative way to deliver cells to vascularized tissues including the central nervous system. Finally we show how to remove the embryo from the egg after several days of further development and how to dissect the spinal cord free for subsequent physiological, histological or biochemical analyses.

In this paper we present a method for transplanting human stem cells into various regions of the central nervous system of the chicken embryo. This provides an in vivo model for assessing the proliferation and differentiation of various types of human stem cells in embryonic tissue environments.

Xenotransplante de células-tronco humanas no embrião de galinha

The chicken embryo is a classical animal model for studying normal embryonic and fetal development and for xenotransplantation experiments to study the ...

Clonogenic Assay: Adherent Cells

The clonogenic (or colony forming) assay has been established for more than 50 years; the original paper describing the technique was published in 19561. Apart from documenting the method, the initial landmark study generated the first radiation-dose response curve for X-ray irradiated mammalian (HeLa) cells in culture1. Basically, the clonogenic assay enables an assessment of the differences in reproductive viability (capacity of cells to produce progeny; i.e. a single cell to form a colony of 50 or more cells) between control untreated cells and cells that have undergone various treatments such as exposure to ionising radiation, various chemical compounds (e.g. cytotoxic agents) or in other cases genetic manipulation. The assay has become the most widely accepted technique in radiation biology and has been widely used for evaluating the radiation sensitivity of different cell lines. Further, the clonogenic assay is commonly used for monitoring the efficacy of radiation modifying compounds and for determining the effects of cytotoxic agents and other anti-cancer therapeutics on colony forming ability, in different cell lines. A typical clonogenic survival experiment using adherent cells lines involves three distinct components, 1) treatment of the cell monolayer in tissue culture flasks, 2) preparation of single cell suspensions and plating an appropriate number of cells in petri dishes and 3) fixing and staining colonies following a relevant incubation period, which could range from 1-3 weeks, depending on the cell line. Here we demonstrate the general procedure for performing the clonogenic assay with adherent cell lines with the use of an immortalized human keratinocyte cell line (FEP-1811)2. Also, our aims are to describe common features of clonogenic assays including calculation of the plating efficiency and survival fractions after exposure of cells to radiation, and to exemplify modification of radiation-response with the use of a natural antioxidant formulation.

The applicability of the clonogenic assay for evaluating reproductive viability has been established for more than 50 years. Here we demonstrate the general procedure for performing the clonogenic assay with adherent cells.

Clonogênica Ensaio: células aderentes

The clonogenic (or colony forming) assay has been established for more than 50 years; the original paper describing the technique was published in 19561. ...

Modified Mouse Embryonic Stem Cell based Assay for Quantifying  Cardiogenic Induction Efficiency

Differentiation of pluripotent stem cells is tightly controlled by temporal and spatial regulation of multiple key signaling pathways. One of the hurdles to its understanding has been the varied methods in correlating changes of key signaling events to differentiation efficiency. We describe here the use of a mouse embryonic stem (ES) cell based assay to identify critical time windows for Wnt/&beta;-catenin and BMP signal activation during cardiogenic induction. By scoring for contracting embryonic bodies (EBs) in a 96-well plate format, we can quickly quantify cardiogenic efficiency and identify crucial time windows for Wnt/&beta;-catenin and BMP signal activation in a time course following specific modulator treatments. The principal outlined here is not limited to cardiac induction alone, and can be applied towards the study of many other cell lineages. In addition, the 96-well format has the potential to be further developed as a high throughput, automated assay to allow for the testing of more sophisticated experimental hypotheses.

We describe the use of a mouse ES cell based assay to identify critical time windows for Wnt/&#946;-catenin and BMP signal activation during cardiogenic induction. The method provides a standardized platform that reliably quantifies cardiogenic efficiency, and it is applicable to the study of other cell lineages.

Modificado embrionárias de camundongos com células-tronco Ensaio baseado para quantificar a eficiência de indução cardiogênico

Differentiation of pluripotent stem cells is tightly controlled by temporal and spatial regulation of multiple key signaling pathways.  One of the hurdles ...

Tracking Morphogenetic Tissue Deformations in the Early Chick Embryo

Embryonic epithelia undergo complex deformations (e.g. bending, twisting, folding, and stretching) to form the primitive organs of the early embryo. Tracking fiducial markers on the surfaces of these cellular sheets is a well-established method for estimating morphogenetic quantities such as growth, contraction, and shear. However, not all surface labeling techniques are readily adaptable to conventional imaging modalities and possess different advantages and limitations. Here, we describe two labeling methods and illustrate the utility of each technique. In the first method, hundreds of fluorescent labels are applied simultaneously to the embryo using magnetic iron particles. These labels are then used to quantity 2-D tissue deformations during morphogenesis. In the second method, polystyrene microspheres are used as contrast agents in non-invasive optical coherence tomography (OCT) imaging to track 3-D tissue deformations. These techniques have been successfully implemented in our lab to studythe physical mechanisms of early head fold, heart, and brain development, and should be adaptable to a wide range morphogenetic processes.

This article describes surface labeling and ex ovo tissue culture in the early chick embryo. Techniques amenable to time-lapse bright field, fluorescence, and optical coherence tomography imaging are presented. Tracking surface labels with high spatiotemporal resolution enables kinematic quantities such as morphogenetic strains (deformations) to be calculated in both two and three dimensions.

Rastreamento Deformações Tissue Morfogenéticas no embrião de galinha precoce

Embryonic epithelia undergo complex deformations (e.g. bending, twisting, folding, and stretching) to form the primitive organs of the early embryo. ...