我们要感谢保罗·普瓦里耶，媒体制作，在圣文森特山大学为他的拍摄工作和编辑这篇稿子的视频部分。我们承认自然科学加拿大与工程研究理事会资助。

注:所有用品都列在表1中。 1.存放鸡胚<ol><li>孵育应变鸡水平鸡在37℃，大约40％的湿度的鸡蛋，把鸡蛋一次或每天两次。翻蛋重要的是要防止胚胎附着在蛋壳。 </li><li>不打开鸡蛋在24小时之前，建立培养另有胚胎将位于腹侧蛋黄的质量和在打开鸡蛋在步骤3除了将被损坏，保持蛋在4℃下度孵化，以"叫停"开发前不超过一个星期，但这种不理想。 </li></ol> 2.分期鸡胚<ol><li>舞台采用汉堡和汉密尔顿12临时表中的鸡胚。设立的前OVO培养的理想阶段是HH阶段19-20（约3-天的潜伏期），BEC澳洲英语这是头转向后不久，在53高倍视野。 注意:HH阶段19-20的特征在于用以下形态学性状:体节延伸到大多数的尾部，但是尾部的最末端保持不分段，尾芽卷曲，尿囊小并且具有有限的脉管，腿芽比翼芽大，眼睛是未染色的，或有一个灰色的色调。 </li></ol> 3.从外壳取下胚胎<ol><li>之前从外壳取出胚胎，喷壳用70％乙醇，并允许其干燥。不要把鸡蛋迅速，因为这会损坏胚胎。 </li><li>小心不要改变卵的取向，小心裂纹蛋上的下侧（即，侧那孵育期间腹侧），并释放该胚胎到无菌称量船（约88 x 88×23毫米）。擦拭称量皿，用70％的乙醇。检查胚胎，以确保黄麻袋不被损坏。如果蛋黄ħ作为破碎，放弃胚胎，因为它会无法生存。 </li><li>观察胚胎，以确保它是可行的;心脏跳动，血管显示正常，未见明显异常存在。确保称量船的边缘是干燥的。 </li><li>使用移液管，滴40微升青霉素/链霉素（5,000单位青霉素，每毫升5毫克链霉素）上的白蛋白的顶部，以防止感染。 </li></ol> 4.准备恒温恒湿箱<ol><li>放置一小叠KIM-湿巾和/或在无菌的塑料容器（12×12×6厘米）的底部由棉的吸收垫擦拭用70％的乙醇。 </li><li>加无菌蒸馏水弄湿KIM-湿巾和/或棉（约150毫升水）。 </li></ol> 5.装配防爆大毛文化<ol><li>将含在潮湿的填充顶部胚胎的权衡船。然后，将半方形无菌培养皿（9.5×9.5厘米）对T顶部他权衡船，形成一个松散的盖子。 </li><li>覆盖塑料容器，其盖子。向下压在盖的两个角，从而确保一局部密封，其仍然允许该腔室内部的良好的气流。 </li><li>小心地将设置到37℃培养箱，直到所需的阶段。 </li><li>放置的水的容器，在培养箱中以帮助控制湿度，如果一个受控湿度培养箱不可用。消毒所有的水在湿室和孵化器和发病期间根据需要及时补充。 40％的湿度是理想的。 </li></ol>

<ol>
	<li>Auerbach, R., Kubai, L., Knighton, D., Folkman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+procedure+for+the+long-term+cultivation+of+chicken+embryos.">A simple procedure for the long-term cultivation of chicken embryos.</a> Dev. Biol. 41, 391-394 (1974).</li><li>Gennaro, L. D., Packard, D. S., Stach, R. W., Wagner, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+and+differentiation+of+chicken+embryos+in+simplified+shell-less+cultures+under+ordinary+conditions+of+incubation.">Growth and differentiation of chicken embryos in simplified shell-less cultures under ordinary conditions of incubation.</a> Growth. 44, 343-354 (1980).</li><li>Tufan, C. A., Akdogan, I., Adiguzel, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shell-less+culture+of+the+chick+embryo+as+a+model+system+in+the+study+of+developmental+neurobiology.">Shell-less culture of the chick embryo as a model system in the study of developmental neurobiology.</a> Neuroanat. 3, 8-11 (2004).</li><li>Duench, K., Franz-Odendaal, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BMP+and+Hedgehog+signaling+during+the+development+of+scleral+ossicles.">BMP and Hedgehog signaling during the development of scleral ossicles.</a> Dev. Biol. 365 (1), 251-258 (2012).</li><li>Datar, S., Bhonde, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shell-less+Chick+Embryo+Culture+as+an+Alternative+in+vitro+Model+to+Investigate+Glucose-Induced+Malformation+in+Mammalian+Embryos.">Shell-less Chick Embryo Culture as an Alternative in vitro Model to Investigate Glucose-Induced Malformation in Mammalian Embryos.</a> Rev Diabet Stud. 2 (4), 221-227 (2005).</li><li>Fisher, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chick+embryos+in+shell-less+culture.+Tested+studies+for+laboratory+teaching.">Chick embryos in shell-less culture. Tested studies for laboratory teaching.</a> , (1983).</li><li>Dunn, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technique+for+shell-less+culture+of+the+72-hour+avian+embryo).">Technique for shell-less culture of the 72-hour avian embryo).</a> Poultry Science. 53, 409-412 (1974).</li><li>Yalcin, H., Shekhar, A., Rane, A. A., Butcher, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+ex-ovo+chicken+embryo+culture+system+suitable+for+imaging+and+microsurgery+applications.">An ex-ovo chicken embryo culture system suitable for imaging and microsurgery applications.</a> J. Vis. Exp. (44), (2010).</li><li>Silver, P. H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Special+problems+of+experimenting+in+ovo+on+the+early+chick+embryo,+and+a+solution.">Special problems of experimenting in ovo on the early chick embryo, and a solution.</a> J Embryol Exp Morph. 8 (4), 369-375 (1960).</li><li>Spurlin, J., Lwigale, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+technique+to+increase+accessibility+to+late-stage+chick+embryos+for+in+ovo+manipulations.">A technique to increase accessibility to late-stage chick embryos for in ovo manipulations.</a> Dev. Dyn. 242 (2), 148-154 (2012).</li><li>Dorrell, M. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+ovo+model+for+directly+visualizing+chicken+embryo+development.">Ex ovo model for directly visualizing chicken embryo development.</a> American Biology Teacher. 74 (9), (2012).</li><li>Hamburger, V., Hamilton, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+series+of+normal+stages+in+the+development+of+the+chick+embryo.">A series of normal stages in the development of the chick embryo.</a> J. Morph. 88, 49-92 (1951).</li><li>Drossopoulou, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+model+for+anteroposterior+patterning+of+the+vertebrate+limb+based+on+sequential+long-and+short-range+Shh+signaling+and+Bmp+signaling.">A model for anteroposterior patterning of the vertebrate limb based on sequential long-and short-range Shh signaling and Bmp signaling.</a> Development. , 127-1337 (2000).</li><li>Sys, G. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+in+ovo+CAM-assay+as+a+xenograft+model+for+sarcoma.">The in ovo CAM-assay as a xenograft model for sarcoma.</a> J. Vis. Exp. (77), e50522 (2013).</li><li>Franz-Odendaal, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+understanding+the+development+of+scleral+ossicles+in+chicken,+Gallus+gallus.">Towards understanding the development of scleral ossicles in chicken, Gallus gallus.</a> Dev. Dyn. 237, 3240-3251 (2008).</li></ol>

笔者在对在这个手稿所提供的信息没有竞争经济利益。

前大毛培养和窗口都有优点和挑战。在这里，我们比较一下优点和泡沫塑料杯前卵内的方法和开窗的方法对我们的优化卵内的方法当然在这里显示的挑战。我们的方法能够操纵和便于观察小鸡胚胎在发育的后期阶段，我们的改进传统的前卵方法1，2，3，使其附加地很容易在本科教学实验室类使用。 虽然许多研究人员更加窗方法来研究鸡发展，因为它是简单的执行，并具有极好的可生存的发展晚期（HH 41-42），它有局限性。其中最大的是能力有限，查看HH阶段30后，整个胚胎阶段后HH 30，在蛋壳的窗口需要是为了查看越来越大，移动的胚胎非常大。这个大窗口的difficult密封完全（导致问题的不育和生存能力），并取得良好的照明蛋内是具有挑战性的。此外，晚期胚胎是通过窗口大而难以进入（或操纵）。 大毛方法前这里描述提供了完整的不羁进入胚胎。一旦称重舟放置在湿度室中，整个的建立是非常稳定的。整个湿度箱可以放置在解剖显微镜下和高放大倍数可以用于观察整个胚胎。相比较而言，该泡沫聚苯乙烯杯法具有湿度室，其是高（杯高度），这使得它在显微镜下的目标放置非常困难。杯子的设计也远远比平面不太稳定的权衡船，这些杯子很容易被打翻。我们对前OVO方法的改进让这个简单的方法在教室或实验室环境中使用，使STudent有通过对HH 40全面进入从舞台HH 19胚胎;当主要器官发生阶段。我们前大毛方法的最大缺点是不育。为了防止感染，我们的方法包括在加入抗生素。抗生素的另一种剂量可在稍后阶段给予胚胎。在培养建立施用抗生素也似乎不影响胚胎的发育。灭菌容器一起使用可以显着提高的生存能力现有的70％的乙醇。 总体而言， 前大毛方法最适用于查看和操作胚胎不会对接入的发展或舞台限制。以前的研究已经表明，培养所述胚卵前不会负面构图4,15影响。例如，我们没有看到在图案化或诱导的骨架的任何变化，尽管没有蛋壳。我们的改进方法解决了多ç与当前的传统前卵方法1,2，3存在hallenges。

Ex ovo culturing has played an important role in the study of development of the chicken1, 2. This culturing method has been used to study neurological diseases, limb development, craniofacial development, and as a model to investigate malformations associated with diabetes 3, 4, 5.
There are many variations to the ex ovo technique. The most common approach is to use a Styrofoam cup6,7,8 or a glass bowl5. In these methods, the cup or bowl is lined with plastic wrap to cradle the embryo, a lid is placed on the cup, and the embryo is then placed in an incubator with appropriate humidity6. This set up however, can be technically challenging. The first challenge is the plastic wrap that is used to cradle the embryo. This wrap is difficult to work with and often does not adhere to the cup very well. To solve this problem, an elastic band is placed around the cup to hold the wrap in place. Despite this, the wrap can still slip, which is fatal to the embryo. The plastic wrap has the potential to tear or get punctured by forceps or needles that may be used during embryo manipulations and observations. Finally, this set-up is not very stable and students can easily knock the cups over. The height of the cups also makes it very difficult to place the embryo under a stereomicroscope, which has a limited objective to stage height. These challenges make it difficult for undergraduate students to work with live chick embryos in teaching labs, such as advanced developmental biology courses. 
The above challenges in the ex ovo method has meant that researchers turn to the windowing method 9,10 to view embryonic chick development. In this technique, a hole or &#8220;window&#8221; is made in the eggshell overlying the embryo. The hole can be re-sealed with tape or wax9 to allow for further embryonic development. Although the windowing method has some advantages, such as the ability to view embryonic development and easy maintenance, this method also has several limitations. The first is that the window needs to be fairly large in order to view the entire embryo (especially at late stages). Secondly, large windows are difficult to seal; an improper seal will lead to sterility and survivability problems. Using molten wax as a sealant adds another inconvenient and messy step to the protocol. Therefore, although the windowing method may be ideal for chick embryos at young stages (HH 11 &#8211; HH 27), viewing the entire embryo at late stages is not easily accomplished. 
Here, we describe an improved and simple ex ovo culturing technique11 that avoids the need for high tech equipment, is easy to handle under a stereomicroscope, gives the embryo enough support to perform microscopic manipulations, and enables researchers to view the growth of the embryo in its entirety well into the later stages of development (up to HH 40-41). With these advances in the ex ovo technique, individuals gain access to a more complete understanding of embryonic development. For instance, growth into later stages allows individuals to observe developmental processes that do not occur until this time point, such as ossification, feather development, and advanced limb and eye development. The entire embryo and extraembryonic membranes and vasculature are clearly visible. More advanced research can also be performed, such as, embryonic manipulations (i.e., implanting beadssoaked in inhibitors or inserting barriers between tissue layers), and researchers are then able to observe the effect of the manipulations in later stage embryos.

<table border="0" cellpadding="0" cellspacing="0" width="658">
	<tbody>
		<tr height="78">
			<td height="78" style="height:79px;width:177px;">Penicillin/Streptomycin</td>
			<td style="width:136px;">Sigma</td>
			<td style="width:152px;">P4458</td>
			<td style="width:192px;">Make small aliquots to avoid freeze/thaw events</td>
		</tr>
		<tr height="22">
			<td height="61" rowspan="3" style="height:61px;width:177px;">Square Petri Dish</td>
			<td rowspan="3" style="width:136px;">N/A</td>
			<td rowspan="3" style="width:152px;">N/A</td>
			<td rowspan="3" style="width:192px;">9.5 cm x 9.5 cm</td>
		</tr>
		<tr height="19">
		</tr>
		<tr height="20">
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:177px;">Weigh Boat</td>
			<td style="width:136px;">Fischer Scientific</td>
			<td align="right" style="width:152px;">8732113</td>
			<td style="width:192px;">88 x 88 x 23 mm</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:177px;">Ziplock container</td>
			<td style="width:136px;">Ziplock</td>
			<td style="width:152px;">N/A</td>
			<td style="width:192px;">12 cm x 12 cm x 6 cm</td>
		</tr>
	</tbody>
</table>

optimized ex-ovo culturing of chick embryos to advanced stages of development

Research in anatomy, embryology, and developmental biology has largely relied on the use of model organisms. In order to study development in live embryos model organisms, such as the chicken, are often used. The chicken is an excellent model organism due to its low cost and minimal maintenance, however they present observational challenges because they are enclosed in an opaque eggshell. In order to properly view the embryo as it develops, the shell must be windowed or removed. Both windowing and ex ovo techniques have been developed to assist researchers in the study of embryonic development. However, each of the methods has limitations and challenges. Here, we present a simple, optimized ex ovo culture technique for chicken embryos that enables the observation of embryonic development from stage HH 19 into late stages of development (HH 40), when many organs have developed. This technique is easy to adopt in both undergraduate classes and more advanced research laboratories where embryo manipulations are conducted.

这当然大毛方法可以从开发的初期阶段（HH 19/20），观察胚胎的发展（ 图1B和1A），后期（HH 40-41）。建立文化的HH 19-20增加了文化的胚胎存活。在此之前的头部转动（前53 HPF）生存能力是很低的文化和级21之后，胚胎往往如此少完整胚获得更粘到上除去外壳。在一般情况下， 前OVO文化的胚胎生存能力更是高达35-36 HH（90-100％），但它确实下降的发展更高级阶段（约40％生存到HH 40-41）。另外，尽管已经显示，发展出现正常在这些晚期和骨架的图案形成不受影响4,15，我们已经观察到四肢弯曲这些后期表明骨化的程度或定时可能会受到影响。这是并不奇怪，考虑是否需要补钙从壳骨化。与对照组相比胚胎发育的详细对比正在进行，超出了本文的方法的范围。 获得进入整个胚胎的发展主要有两个重要的原因。首先，研究人员能够查看发展，每天无需启封并重新密封的窗口。例如，个人都能够观察肢体和眼睛发育的多个阶段（ 图1C和1D）。其次， 前大毛培养能够取得更大的（无限制）进入胚胎，从而使操作更加容易，或手术。 胚胎操作次数最多，需要使用立体显微镜来进行。使用前卵此处所描述，相对于泡沫塑料/保鲜方法6,7,8培养方法胚胎建立易于UND放置呃显微镜，还不深，不会翻倒。这使得研究者能够根据需要并旋转它来优化获得的胚胎精确地定位的恒湿室中，由于不存在障碍（蛋壳）混淆胚胎，并且由于腔室是非常稳定的。总体而言，胚胎接收来自称量舟的支持允许温和的压力被操纵期间没有集式翻倒施加到胚胎。 几个发育生物学方法可以在这种文化体系中的胚胎进行。这些措施包括器官的详细观察（ 如眼，脑等）或组织发展（ 如，血管生长）或应用程序的致畸剂。操纵包括组织上的绒毛尿囊膜的接枝来研究组合不同的组织层或学习肿瘤生长和转移14的效果。在开发过程中进行的另一种流行的操控是BEAd或屏障植入。珠注入允许研究者浸泡抑制剂或因子到胎圈，然后植入珠局部地抑制或在感兴趣的区域局部地诱导基因。这通常是用AffiGel或肝素珠（ 图2A）。例如，骨形态发生蛋白（BMPs），可以局部地诱导神经嵴源性骨4,15期间抑制，或在显影肢芽13。后的珠被植入，胚胎可以放回培养箱，它会继续发展。这使得研究人员能够查看特定基因的抑制（在这种情况下，BMP），下游效应，如巩膜听小骨的形成，在硬化环的抑制（ 图2B和2C）15。同样，屏障可以容易地组织层之间，以便研究组织到组织信令和染料的显微注射也可以很容易地进行插入。 </p&gt; <img alt="图1" src="/files/ftp_upload/52129/52129fig1.jpg" /> 图1.查看胚胎前OVO。（A）HH阶段去除后壳20鸡胚，箭头指向与血管胚胎膜的胚胎。（B）一个HH阶段40胚胎在一个开放的湿度室。（C） HH阶段35胚胎早期呈现肢芽（箭头）。（D）阶段HH 41胚胎显示后期发展结构，如眼睛（箭头）。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52129/52129fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/52129/52129fig2.jpg" /> 头蛋白图2.示例浸泡珠植入ExperimENT 4（A）胚胎HH阶段35通过一个小孔撕开的覆膜，以获得潜在的眼睛珠子植入暴露。高倍率邻近结膜乳头的affigel珠粒示于插图。在C中比例尺为75微米。（B）碱性磷酸酶染色右眼后，头蛋白珠植入（箭头），显示差距小骨的戒指，HH 38（C）AP染色左眼呈现给听小骨的环不会中断（控制），HH这个实验38.详细情况Duench和弗朗兹- Odendaal 4提供。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52129/52129fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development at JoVE.com

Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development

Viewing and accessing the chicken embryo during development can be challenging. We have developed an ex ovo method that is simple, cost effective, and can easily be used in a classroom or research setting. This method provides access to the embryo into late stages of embryonic development (HH 40).

优化<em&gt;前OVO</em&gt;鸡胚培养，以发展的高级阶段

Research in anatomy, embryology, and developmental biology has largely relied on the use of model organisms. In order to study development in live embryos ...

optimized-ex-ovo-culturing-chick-embryos-to-advanced-stages

Nanyang Technological University

Research

JoVE Journal

Developmental Biology

Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development

13.5K 次观看.  Mount Saint Vincent University. Viewing and accessing the chicken embryo during development can be challenging. We have developed an ex ovo method that is simple, cost effective, and can easily be used in a classroom or research setting. This method provides access to the embryo into late stages of embryonic development (HH 40). 

视频: Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

The cone photoreceptor-enriched cultures derived from embryonic chick retinas have become an indispensable tool for researchers around the world studying the biology of retinal neurons, particularly photoreceptors. The applications of this system go beyond basic research, as they can easily be adapted to high throughput technologies for drug development. However, genetic manipulation of retinal photoreceptors in these cultures has proven to be very challenging, posing an important limitation to the usefulness of the system. We have recently developed and validated an ex&#160;ovo plasmid electroporation technique that increases the rate of transfection of retinal cells in these cultures by five-fold compared to other currently available protocols1. In this method embryonic chick eyes are enucleated at stage 27, the RPE is removed, and the retinal cup is placed in a plasmid-containing solution and electroporated using easily constructed custom-made electrodes. The retinas are then dissociated and cultured using standard procedures. This technique can be applied to overexpression studies as well as to the downregulation of gene expression, for example via the use of plasmid-driven RNAi technology, commonly achieving transgene expression in 25% of the photoreceptor population. The video format of the present publication will make this technology easily accessible to researchers in the field, enabling the study of gene function in primary retinal cultures. We have also included detailed explanations of the critical steps of this procedure for a successful outcome and reproducibility.

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

Embryonic chick retinal cell cultures constitute valuable tools for the study of photoreceptor biology. We have developed an efficient gene transfer technique based on ex&#160;ovo plasmid electroporation of the retinas prior to culture. This technique considerably increases transfection efficiencies over currently available protocols, making genetic manipulation feasible for this system.

在小鸡视网膜有效的基因转移的原代细胞培养研究:<em&gt;前OVO</em&gt;电穿孔法

The cone photoreceptor-enriched cultures derived from embryonic chick retinas have become an indispensable tool for researchers around the world studying ...

科研

发育生物学

Forward Genetic Approach to Uncover Stress Resistance Genes in Mice &#8212; A High-throughput Screen in ES Cells

Phenotype-driven genetic screens in mice is a powerful technique to uncover gene functions, but are often hampered by extremely high costs, which severely limits its potential. We describe here the use of mouse embryonic stem (ES) cells as surrogate cells to screen for a phenotype of interest and subsequently introduce these cells into a host embryo to develop into a living mouse carrying the phenotype. This method provides (1) a cost effective, high-throughput platform for genetic screen in mammalian cells; (2) a rapid way to identify the mutated genes and verify causality; and (3) a short-cut to develop mouse mutants directly from these selected ES cells for whole animal studies. We demonstrated the use of paraquat (PQ) to select resistant mutants and identify mutations that confer oxidative stress resistance. Other stressors or cytotoxic compounds may also be used to screen for resistant mutants to uncover novel genetic determinants of a variety of cellular stress resistance.

Stress resistance is one of the hallmarks for longevity and is known to be genetically governed. Here, we developed an unbiased high-throughput method to screen for mutations that confer stress resistance in ES cells with which to develop mouse models for longevity studies.

正向遗传学的方法来揭开抗逆基因小鼠 - 在ES细胞高通量筛选

Phenotype-driven genetic screens in mice is a powerful technique to uncover gene functions, but are often hampered by extremely high costs, which severely ...

A Novel Ex Ovo Banding Technique to Alter Intracardiac Hemodynamics in an Embryonic Chicken System

The new model presented here can be used to understand the influence of hemodynamics on specific cardiac developmental processes, at the cellular and molecular level. To alter intracardiac hemodynamics, fertilized chicken eggs are incubated in a humidified chamber to obtain embryos of the desired stage (HH17). Once this developmental stage is achieved, the embryo is maintained ex ovo and hemodynamics in the embryonic heart are altered by partially constricting the outflow tract (OFT) with a surgical suture at the junction of the OFT and ventricle (OVJ). Control embryos are also cultured ex ovo but are not subjected to the surgical intervention. Banded and control embryos are then incubated in a humidified incubator for the desired period of time, after which 2D ultrasound is employed to analyze the change in blood flow velocity at the OVJ as a result of OFT banding. Once embryos are maintained ex ovo, it is important to ensure adequate hydration in the incubation chamber so as to prevent drying and eventually embryo death. Using this new banded model, it is now possible to perform analyses of changes in the expression of key players involved in valve development and to understand the role of hemodynamics on cellular responses in vivo, which could not be achieved previously.

A Novel Ex Ovo Banding Technique to Alter Intracardiac Hemodynamics in an Embryonic Chicken System

For the first time we present here a reproducible banding procedure to alter hemodynamics in the developing heart ex ovo. This is achieved by partially constricting the outflow tract (OFT).

一本小说<em&gt;防爆大毛</em&gt;带技术来改变心内血流动力学在鸡胚胎系统

The new model presented here can be used to understand the influence of hemodynamics on specific cardiac developmental processes, at the cellular and ...

A Submerged Filter Paper Sandwich for Long-term Ex Ovo Time-lapse Imaging of Early Chick Embryos

Due to its availability, low cost, flat geometry, and transparency, the ex ovo chick embryo has become a major vertebrate animal model for the study of morphogenetic events, such as gastrulation2, neurulation3-5, somitogenesis6, heart bending7,8, and brain formation9-13, during early embryogenesis. Key to understanding morphogenetic processes is to follow them dynamically by time-lapse imaging. The acquisition of time-lapse movies of chick embryogenesis ex ovo has been limited either to short time windows or to the need for an incubator to control temperature and humidity around the embryo14. Here, we present a new technique to culture chick embryos ex ovo for high-resolution time-lapse imaging using transmitted light microscopy. The submerged filter paper sandwich is a variant of the well-established filter paper carrier technique (EC-culture)1 and allows for the culturing of chick embryos without the need for a climate chamber. The embryo is sandwiched between two identical filter paper carriers and is kept fully submerged in a simple, temperature-controlled medium covered by a layer of light mineral oil. Starting from the primitive streak stage (Hamburger-Hamilton stage 5, HH5)15 up to at least the 28-somite stage (HH16)15, embryos can be cultured with either their ventral or dorsal side up. This allows the acquisition of time-lapse movies covering about 30 hr of embryonic development. Representative time-lapse frames and movies are shown. Embryos are compared morphologically to an embryo cultured in the standard EC-culture.
The submerged filter paper sandwich provides a stable environment to study early dorsal and ventral morphogenetic processes. It also allows for live fluorescence imaging and micromanipulations, such as microsurgery, bead implantation, microinjection, gene silencing, and electroporation, and has a strong potential to be combined with immersion objectives for laser-based imaging (including light-sheet microscopy).

A Submerged Filter Paper Sandwich for Long-term Ex Ovo Time-lapse Imaging of Early Chick Embryos

Here, we present a new technique to culture chick embryos ex ovo for time-lapse imaging using transmitted light and fluorescence microscopy. The submerged filter paper sandwich is a variant of the well-established filter paper carrier technique1 that allows for the culturing of chick embryos fully-submerged in a liquid culture medium.

水下滤纸三明治长期<em&gt;防爆大毛</em&gt;早期鸡胚时间推移成像

Due to its availability, low cost, flat geometry, and transparency, the ex ovo chick embryo has become a major vertebrate animal model for the study of ...

Induction of Hypoxia in Living Frog and Zebrafish Embryos

Here, we introduce a novel system for hypoxia induction, which we developed to study the effects of hypoxia in aquatic organisms such as frog and zebrafish embryos. Our system comprises a chamber featuring a simple setup that is nevertheless robust to induce and maintain a specific oxygen concentration and temperature in any experimental solution of choice. The presented system is very cost-effective but highly functional, it allows induction and sustainment of hypoxia for direct experiments in vivo and for various time periods up to 48 h.
To monitor and study the effects of hypoxia, we have employed two methods - measurement of levels of hypoxia-inducible factor 1alpha (HIF-1&#945;) in whole embryos or specific tissues and determination of retinal stem cell proliferation by 5-ethynyl-2&#8242;-deoxyuridine (EdU) incorporation into the DNA. HIF-1&#945; levels can serve as a general hypoxia marker in the whole embryo or tissue of choice, here embryonic retina. EdU incorporation into the proliferating cells of embryonic retina is a specific output of hypoxia induction. Thus, we have shown that hypoxic embryonic retinal progenitors decrease proliferation within 1 h of incubation under 5% oxygen of both frog and zebrafish embryos.
Once mastered, our setup can be employed for use with small aquatic model organisms, for direct in vivo experiments, any given time period and under normal, hypoxic or hyperoxic oxygen concentration or under any other given gas mixture.

We introduce a novel hypoxic chamber system for use with aquatic organisms such as frog and zebrafish embryos. Our system is simple, robust, cost-effective and allows the induction and sustainment of hypoxia in vivo and for up to 48 h. We present 2 reproducible methods to monitor the effectiveness of hypoxia.

诱导生活青蛙和斑马鱼胚胎缺氧

Here, we introduce a novel system for hypoxia induction, which we developed to study the effects of hypoxia in aquatic organisms such as frog and ...

Multi-Photon Time Lapse Imaging to Visualize Development in Real-time: Visualization of Migrating Neural Crest Cells in Zebrafish Embryos

Congenital eye and craniofacial anomalies reflect disruptions in the neural crest, a transient population of migratory stem cells that give rise to numerous cell types throughout the body. Understanding the biology of the neural crest has been limited, reflecting a lack of genetically tractable models that can be studied in vivo and in real-time. Zebrafish is a particularly important developmental model for studying migratory cell populations, such as the neural crest. To examine neural crest migration into the developing eye, a combination of the advanced optical techniques of laser scanning microscopy with long wavelength multi-photon fluorescence excitation was implemented to capture high-resolution, three-dimensional, real-time videos of the developing eye in transgenic zebrafish embryos, namely Tg(sox10:EGFP) and Tg(foxd3:GFP), as sox10 and foxd3 have been shown in numerous animal models to regulate early neural crest differentiation and likely represent markers for neural crest cells. Multi-photon time-lapse imaging was used to discern the behavior and migratory patterns of two neural crest cell populations contributing to early eye development. This protocol provides information for generating time-lapse videos during zebrafish neural crest migration, as an example, and can be further applied to visualize the early development of many structures in the zebrafish and other model organisms.

A combination of the advanced optical techniques of laser scanning microscopy with long wavelength multi-photon fluorescence excitation was implemented to capture high-resolution, three-dimensional, real-time imaging of neural crest migration in Tg(sox10:EGFP) and Tg(foxd3:GFP) zebrafish embryos.

多光子时间推移成像实时可视化发展: 迁移神经嵴细胞在斑马鱼胚胎中的可视化

Congenital eye and craniofacial anomalies reflect disruptions in the neural crest, a transient population of migratory stem cells that give rise to ...

Development of an In Vitro Assay to Quantitate Hematopoietic Stem and Progenitor Cells (HSPCs) in Developing Zebrafish Embryos

Hematopoiesis is an essential cellular process in which hematopoietic stem and progenitor cells (HSPCs) differentiate into the multitude of different cell lineages that comprise mature blood. Isolation and identification of these HSPCs is difficult because they are defined ex post facto; they can only be defined after their differentiation into specific cell lineages. Over the past few decades, the zebrafish (Danio rerio) has become a model organism to study hematopoiesis. Zebrafish embryos develop ex utero, and by 48 h post-fertilization (hpf) have generated definitive HSPCs. Assays to assess HSPC differentiation and proliferation capabilities have been developed, utilizing transplantation and subsequent reconstitution of the hematopoietic system in addition to visualizing specialized transgenic lines with confocal microscopy. However, these assays are cost prohibitive, technically difficult, and time consuming for many laboratories. Development of an in vitro model to assess HSPCs would be cost effective, quicker, and present fewer difficulties compared to previously described methods, allowing laboratories to quickly assess mutagenesis and drug screens that affect HSPC biology. This novel in vitro assay to assess HSPCs is performed by plating dissociated whole zebrafish embryos and adding exogenous factors that promote only HSPC differentiation and proliferation. Embryos are dissociated into single cells and plated with HSPC-supportive colony stimulating factors that cause them to generate colony forming units (CFUs) that arise from a single progenitor cell. These assays should allow more careful examination of the molecular pathways responsible for HSPC proliferation, differentiation, and regulation, which will allow researchers to understand the underpinnings of vertebrate hematopoiesis and its dysregulation during disease.

Development of an In Vitro Assay to Quantitate Hematopoietic Stem and Progenitor Cells HSPCs in Developing Zebrafish Embryos

Here, we present a simple method to quantitate hematopoietic stem and progenitor cells (HSPCs) in embryonic zebrafish. HSPCs from dissociated zebrafish are plated in methylcellulose with supportive factors, differentiating into mature blood. This allows the detection of blood defects and allows drug screening to be easily conducted.

定量造血干和祖细胞 (HSPCs) 在斑马鱼胚胎发育中的体外试验研究

Hematopoiesis is an essential cellular process in which hematopoietic stem and progenitor cells (HSPCs) differentiate into the multitude of different cell ...

Whole-Mount In Situ Hybridization in Zebrafish Embryos and Tube Formation Assay in iPSC-ECs to Study the Role of Endoglin in Vascular Development

Vascular development is determined by the sequential expression of specific genes, which can be studied by performing in situ hybridization assays in zebrafish during different developmental stages. To investigate the role of endoglin(eng) in vessel formation during the development of hereditary hemorrhagic telangiectasia&#160;(HHT), morpholino-mediated targeted knockdown of eng in zebrafish are used to study its temporal expression and associated functions. Here, whole-mount in situ RNA hybridization (WISH) is employed for the analysis of eng and its downstream genes in zebrafish embryos. Also, tube formation assays are performed in HHT patient-derived induced pluripotent stem cell-differentiated&#160;endothelial cells (iPSC-ECs; with eng mutations). A specific signal amplifying system using the whole amount In Situ Hybridization &#8211; WISH provides higher resolution and lower background results compared to traditional methods. To obtain a better signal, the post-fixation time is adjusted to 30 min after probe hybridization. Because fluorescence staining is not sensitive in zebrafish embryos, it is replaced with diaminobezidine (DAB) staining here. In this protocol, HHT&#160;patient-derived iPSC lines containing an eng mutation are differentiated into endothelial cells. After coating a plate with basement membrane matrix for 30 min at 37 &#176;C, iPSC-ECs are seeded as a monolayer into wells and kept at 37 &#176;C for 3 h. Then, the tube length and number of branches are calculated using microscopic images. Thus, with this improved WISH protocol, it is shown that reduced eng expression affects endothelial progenitor formation in zebrafish embryos. This is further confirmed by tube formation assays using iPSC-ECs derived from a patient with HHT. These assays confirm the role for eng in early vascular development.

Presented here is a protocol for whole-mount in situ RNA hybridization analysis in zebrafish and tube formation assay in patient-derived induced pluripotent stem cell-derived endothelial cells to study the role of endoglin in vascular formation.

斑马鱼胚胎全山原位杂交和管状测定在iPSC-ECs中研究恩多林在血管发育中的作用

Vascular development is determined by the sequential expression of specific genes, which can be studied by performing in situ hybridization assays in ...

Preparation of Small RNA Libraries for Sequencing from Early Mouse Embryos

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs during early development are technically challenging due to the limiting cell number. Moreover, many approaches require a miRNA of interest to be defined in assays such as northern blotting, microarray, and qPCR. Therefore, the expression of many miRNAs and their isoforms have not been studied during early development. Here, we demonstrate a protocol for small RNA sequencing of sorted cells from early mouse embryos to enable relatively unbiased profiling of miRNAs in early populations of neural crest cells. We overcome the challenges of low cell input and size selection during library preparation using amplification and gel-based purification. We identify embryonic age as a variable accounting for variation between replicates and stage-matched mouse embryos must be used to accurately profile miRNAs in biological replicates. Our results suggest that this method can be broadly applied to profile the expression of miRNAs from other lineages of cells. In summary, this protocol can be used to study how miRNAs regulate developmental programs in different cell lineages of the early mouse embryo.

We describe a technique for profiling microRNAs in early mouse embryos. This protocol overcomes the challenge of low cell input and small RNA enrichment. This assay can be used to analyze changes in miRNA expression over time in different cell lineages of the early mouse embryo.

为早期小鼠胚胎测序准备小型RNA库

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs ...

A Simple and Effective Transplantation Device for Zebrafish Embryos

Classical embryological manipulations, such as removing cells and transplanting cells within or between embryos, are powerful techniques to study complex developmental processes. Zebrafish embryos are ideally suited for these manipulations since they are easily accessible, relatively large in size, and transparent. However, previously developed devices for cell removal and transplantation are cumbersome to use or expensive to purchase. In contrast, the transplantation device presented here is economical, easy to assemble, and simple to use. In this protocol, we first introduce the handling of the transplantation device as well as its assembly from commercially and widely available parts. We then present three applications for its use: generation of ectopic clones to study signal dispersal from localized sources, extirpation of cells to produce size-reduced embryos, and germline transplantation to generate maternal-zygotic mutants. Finally, we show that the tool can also be used for embryological manipulations in other species such as the Japanese rice fish medaka.

Embryological manipulations such as extirpation and transplantation of cells are important tools to study early development. This protocol describes a simple and effective transplantation device to perform these manipulations in zebrafish embryos.

一种简单有效的斑马鱼胚胎移植装置

Classical embryological manipulations, such as removing cells and transplanting cells within or between embryos, are powerful techniques to study complex ...