这项工作得到了 NIH 的 OD 拨款R24OD031956的支持。我们感谢 Samantha Jalbert、Jill Ralston 和 Cora Anderson 的帮助和支持，以及我们的编辑和匿名同行评审员的有用反馈

所有实验均按照哈佛医学院IACUC（机构动物护理和使用委员会）（IS 00001365_3）的规则和规定进行。灌注和未灌注的成熟白化雄性 非洲爪蟾（Xenopus laevis）的代表性结果均显示。
1. 实验准备 
注意:如果在采样前遵循灌注方案8 ，请跳至步骤 2.2。
<ol><li>确保研究机构已批准本协议中描述的安乐死技术。</li>
	<li>制备 5 g/L MS-222（甲基磺酸三卡因）和 5 g/L 碳酸氢钠的溶液（参见 材料表）。该体积必须大于完全覆盖被安乐死的动物所需的体积。检查 pH 值以确保其为 ≥7。</li>
	<li>通过将 非洲爪蟾 放入安乐死溶液中进行初级安乐死;动物将保持在水中总共 1 小时。</li>
	<li>设置解剖站，以便在取样后立即在冷冻 PBS 或 0.7x PBS9 （取决于实验需要）中冲洗所有组织，检查并在 5x（或更大）放大灯下修剪。该站还必须使用户能够更换所有镊子和剪刀，或者在两次使用之间将它们擦拭干净。</li>
	<li>一旦青蛙在溶液中放置 1 小时，初级安乐死就完成了。取出青蛙并通过执行脚捏来检查疼痛反应的丧失。</li>
	<li>记录动物的适当详细信息，例如物种、品系、性别、年龄和健康状况，以及是否灌注过。称量 非洲爪蟾 的重量并进行任何其他测量，例如鼻子通风口长度。</li>
	<li>将青蛙放在背上，将四肢固定在身体附近（图1）。</li>
	<li>使用解剖剪刀，切开皮肤，沿着中线，然后横向切成两个皮瓣。</li>
	<li>参 照图 2，识别白线并用镊子抓住它并将其从腔腔中拉开。用剪刀小心地切开肌肉组织。从腔壁上做两个襟翼。将所有襟翼切开或固定在一边。</li>
	<li>确定仍在跳动的心脏。使用解剖剪刀减少喙突骨（图2），以更好地进入心脏。 注意:如果心脏在采样前停止跳动，则应注意样本新鲜度已受到影响。</li>
</ol>2. 抽样
注意:如果动物已经灌注，请跳至步骤 2.2。
<ol><li>识别薄心包并用组织钳将其拉紧（图3）。</li>
	<li>使用虹膜切除术剪刀的尖端，轻轻地穿孔心包，注意不要割伤下面的组织。将心包从心脏的 3 个腔室中剥离出来。</li>
	<li>使用镊子抓住心室的顶点，确定它附着在耳廓和动脉干上的位置（图4），并将其切入这些附着物下方（图5）。如果需要，修剪心室，使耳廓或动脉干的组织不可见，并且心室内仍可见浅色瓣膜组织。 注意:在未灌注的动物中，切除心室可能符合继发性安乐死的条件。</li>
	<li>肝脏的 3 个叶将是可见的（图 6 和 图 7）。抓住左叶的边缘（在观察者的右侧）并轻轻提起它，使肝管和囊管可见（图8）。对这些附件下方波瓣的底部 1/3 进行采样（图 9）。</li>
	<li>为了更好地接触雌性青蛙的组织，切除卵巢是有帮助的。识别包裹在称为生发上皮的内脏腹膜层中的卵巢。轻轻移动波瓣，直到它们位于各自的一侧，使附着区域可见（图 10）。这些附着物直接位于配对肾脏的腹侧。</li>
	<li>使用剪刀，尽可能靠近肾脏切除卵巢，而不会损坏它们（图11）。</li>
	<li>检查肝脏的内侧叶（也称为前叶），并注意它如何通过肠系膜和肝胰管（也称为胆总管）连接到胃和十二指肠（图 6、 图 7 和 图 8）。</li>
	<li>使用虹膜切除术剪刀切断肠系膜、肝十二指肠韧带以及与十二指肠相接的肝胰管。切断胰腺和肝胰管与肝脏内侧叶的连接，以免附着深色肝组织（图12）。</li>
	<li>用齿镊子夹住胃，用组织镊子夹住胰腺的上端。在5倍放大镜下，轻轻地将胰腺从胃中取出（图13）。 注意:如果它没有干净地脱落，剩余的胰腺组织将是可见的，并且可以被切成碎片。或者，可以使用虹膜切除术剪刀和组织镊子有方法地分离胰腺。</li>
	<li>参考 图 14A，识别膀胱并将其切除，尽可能靠近泄殖腔切开。丢弃此纸巾。</li>
	<li>参考 图 14B，识别大肠并将其拉紧，以尽可能靠近泄殖腔切断大肠。切除并丢弃整个消化道，切断腹膜与脾脏相连的地方。现在，肥胖的身体将完全可以接触到。</li>
	<li>挑逗脂肪体，使它们位于各自的两侧。脂肪体与腹膜相连的肾脏上方区域将是可见的。抓住左侧脂肪体的底部（观察者的右侧），并用剪刀将其从腹膜上剪下，留出一小块边缘，以免肾脏受损（图15）。</li>
	<li>取出并丢弃剩余的脂肪体。配对的肾脏现在将完全可见。</li>
	<li>在雌性青蛙或具有明显退化输卵管的雄性青蛙中，抓住输卵管并将其从肾脏和泄殖腔中拉开（图16）。切开输卵管与泄殖腔相接的地方，继续将其从肾脏拉开，当它们变得明显时，切断任何明显的腹膜附着物。丢弃此纸巾。</li>
	<li>对剩余的输卵管重复此过程。</li>
	<li>肾脏仍然覆盖着透明的腹膜（腹膜后）10。使用镊子抓住肾脏并切断其下端的腹膜。</li>
	<li>将肾脏从腔腔中取出，使用剪刀将腹膜尽可能靠近肾脏切开，而不会损坏它们（图17）。</li>
	<li>在 5 倍放大镜下，切去多余的腹膜和任何其他剩余组织（脂肪体、脾脏）。如果青蛙是雌性，请确保切除任何剩余的卵巢组织（图18）。如果青蛙是雄性，小心地切除睾丸并检查是否有退化的输卵管，如果不放大，可能无法看到（图19）。</li>
	<li>从动物身上取下别针，将其翻转到腹腔，然后重新固定动物的四肢。</li>
	<li>选择任一后肢进行采样，并固定该肢体的脚。</li>
	<li>从腓肠肌/胫腓骨上方取下杏仁形的皮瓣（图20）。</li>
</ol>

成年 非洲爪蟾 器官的标准化解剖和采样方案

<ol>
	<li>Porro, L. B., Richards, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+dissection+of+the+model+organism+Xenopus+laevis+using+contrast-enhanced+computed+tomography.">Digital dissection of the model organism Xenopus laevis using contrast-enhanced computed tomography.</a> J Anat. 231 (2), 169-191 (2017).</li><li>Ruehl-Fehlert, C., 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=Revised+guides+for+organ+sampling+and+trimming+in+rats+and+mice--part+1.">Revised guides for organ sampling and trimming in rats and mice--part 1.</a> Exp Toxicol Pathol. 55 (23), 91-106 (2003).</li><li>Kittel, B., 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=Revised+guides+for+organ+sampling+and+trimming+in+rats+and+mice--Part+2.+A+joint+publication+of+the+RITA+and+NACAD+groups.">Revised guides for organ sampling and trimming in rats and mice--Part 2. A joint publication of the RITA and NACAD groups.</a> Exp Toxicol Pathol. 55, 413-431 (2004).</li><li>Morawietz, 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=Revised+guides+for+organ+sampling+and+trimming+in+rats+and+mice+-+Part+3+-+A+joint+publication+of+the+RITA+and+NACAD+groups.">Revised guides for organ sampling and trimming in rats and mice - Part 3 - A joint publication of the RITA and NACAD groups.</a> Exp Toxicol Pathol. 55, 433-449 (2004).</li><li>Patmann, M. D., Shewade, L. H., Schneider, K. A., Buchholz, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenopus+tadpole+tissue+harvest.">Xenopus tadpole tissue harvest.</a> Cold Spring Harb Protoc. 2017 (11), 097675 (2017).</li><li>L&#337;w, P., Moln&#225;r, K., Kriska, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+a+Frog+(Rana+sp.).">Dissection of a Frog (Rana sp.).</a> Atlas of Animal Anatomy and Histology. , 213-263 (2016).</li><li>O'Rourke, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amphibians+used+in+research+and+teaching.">Amphibians used in research and teaching.</a> ILAR J. 48 (3), 183-187 (2007).</li><li>Jonas-Closs, R. A., Peshkin, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effective+rapid+blood+perfusion+in+Xenopus.">Effective rapid blood perfusion in Xenopus.</a> JoVE. (issue), e65287 (2023).</li><li>Balls, M., Worley, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amphibian+cells+in+vitro.+II.+Effects+of+variations+in+medium+osmolarity+on+a+permanent+cells+line+isolated+from+Xenopus.">Amphibian cells in vitro. II. Effects of variations in medium osmolarity on a permanent cells line isolated from Xenopus.</a> Exp Cell Res. 76 (2), 333-336 (1973).</li><li>Holz, P. H., Raidal, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+renal+anatomy+of+exotic+species.">Comparative renal anatomy of exotic species.</a> Vet North Am Exot Anim Pract. 9 (1), 1-11 (2006).</li><li>Trott, K. A., 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=Characterization+of+a+Mycobacterium+ulcerans-like+infection+in+a+colony+of+African+tropical+clawed+frogs+(Xenopus+tropicalis).">Characterization of a Mycobacterium ulcerans-like infection in a colony of African tropical clawed frogs (Xenopus tropicalis).</a> Comp Med. 54 (3), 309-317 (2004).</li><li>Fremont-Rahl, J. J., 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=Mycobacterium+liflandii+outbreak+in+a+research+colony+of+Xenopus+(Silurana)+tropicalis+frogs.">Mycobacterium liflandii outbreak in a research colony of Xenopus (Silurana) tropicalis frogs.</a> Vet Pathol. 48 (4), 856-867 (2011).</li><li>Green, S. L., Parker, J., Davis, C., Bouley, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ovarian+hyperstimulation+syndrome+in+gonadotropin-treated+laboratory+South+African+clawed+frogs+(Xenopus+laevis).">Ovarian hyperstimulation syndrome in gonadotropin-treated laboratory South African clawed frogs (Xenopus laevis).</a> J Am Assoc Lab Anim Sci. 46 (3), 64-67 (2007).</li><li>Vitt, L. J., Caldwell, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy+of+amphibians+and+reptiles.+Herpetol.">Anatomy of amphibians and reptiles. Herpetol.</a> Herpetol. , 35-81 (2009).</li></ol>

提交人声明没有竞争利益。

由于该协议旨在最大限度地提高新鲜度，因此某些样品可能包含不需要的组织。例如，肝胰管和一些肠系膜与胰腺一起取样，一些腹膜组织、肾上腺和输尿管将始终与配对的肾脏一起取样。 如果新鲜度不是问题，那么可以使用改进的技术实现更精确的采样。
器官的外观和位置在非洲 爪蟾的性别和物种之间具有可比性。然而，根据动物是否灌注过，组织的颜色会有很大...

尽管成年非洲爪蟾的"数字解剖"已经可用1，但如果没有其他成年模型（例如小鼠2,3,4）的详细指导，成年非洲爪蟾的可复制器官和组织采样仍然具有挑战性。本文旨在为成年非洲爪蟾的准确和可复制的器官取样提供明确的指导，类似于目前可用于其幼虫的器官取样5.强调易于完成，以保持最大的新鲜度，并使所有用户都可以访问该协议。
虽然有针对 Rana sp.6 的详尽解剖指南，以及针对其他anurans 7 的大量课堂解剖指南，但目前没有可用的非洲爪蟾解剖和取样指南。对于那些不熟悉采样实践或两栖动物解剖学的人来说，非洲爪蟾和其他无蟾之间的微小差异使得这些资源对于可复制的组织取样来说并不理想。
许多有价值的组织不包括在本指南中，甚至被丢弃;这是为了保证组织的新鲜度。六个样本足够有限，以确保无论使用者的经验或技能水平如何，都可以在心脏开始跳动后一小时内收集到这些组织。关于收集许多其他组织的更先进和详细的指南正在作为单独的配套文件编写中。
对于经验不足的用户，始终建议首先在因实验以外的原因被安乐死的动物上尝试此协议，然后再对任何难以替代的动物（即转基因、高龄动物等）进行采样。理想情况下，所有取样的动物都是健康的，如果是雌性，则在过去两周内不会排卵。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>5x Magnifying Glass with LED Light and Stand</td>
			<td>amazon.com</td>
			<td>B08QJ6J8P1</td>
			<td>light must not produce heat</td>
		</tr>
		<tr>
			<td>Disposable Transfer Pipets</td>
			<td>VWR</td>
			<td>414004-036</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting Fine-Pointed Forceps</td>
			<td>Fisher Scinetific</td>
			<td>08-875</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting scissors sharp piont, straight 6.5&#34;</td>
			<td>VWR</td>
			<td>76457-374</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissection Tray</td>
			<td>Fisher Scinetific</td>
			<td>14-370-284</td>
			<td>styrofoam sheets are an acceptable alternative</td>
		</tr>
		<tr>
			<td>Euthanasia container</td>
			<td>US Plastic&#160;</td>
			<td>Item&#160;2860</td>
			<td>alternative opaque containers acceptable</td>
		</tr>
		<tr>
			<td>Euthanasia container lid</td>
			<td>US Plastic&#160;</td>
			<td>Item&#160;3047</td>
			<td></td>
		</tr>
		<tr>
			<td>Iridectomy Scissors 6&#34;</td>
			<td>vwr</td>
			<td>470018-938</td>
			<td>iris scissors are an acceptable alternative</td>
		</tr>
		<tr>
			<td>MS-222: Syncaine (formerly tricaine)</td>
			<td>Pentair AES</td>
			<td>TRS1</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS 1x</td>
			<td>Corning</td>
			<td>21-040-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate, Powder, USP</td>
			<td>Fisher Scientific</td>
			<td>18-606-333</td>
			<td></td>
		</tr>
		<tr>
			<td>Specimen Forceps, Serrated</td>
			<td>VWR</td>
			<td>82027-442</td>
			<td></td>
		</tr>
		<tr>
			<td>T-Pins for Dissecting</td>
			<td>Fisher Scinetific</td>
			<td>S99385</td>
			<td></td>
		</tr>
	</tbody>
</table>

techniques for rapidly sampling six crucial organs in adult xenopus

一百多年来，非洲爪蟾一直是理解脊椎动物发育和疾病的强大模式生物。虽然胚胎的实验分析和解剖技术已经有充分的记录，但对成年非洲爪蟾结构和器官的描述，以及与成人一起工作的技术，尚未得到更新，以考虑到定量蛋白质组学和单细胞转录组学等现代方法的要求。从细胞类型和基因为中心的视角，需要在胚胎阶段与在成体组织中进行对比观察。在幼虫向成虫的过渡过程中，幼虫器官的整体结构、形态和解剖位置都发生了重大变化，最明显的是在大规模重塑过程中。建立健全的器官鉴定和解剖标准对于确保在不同实验室进行的研究得出的数据集能够保持一致至关重要。本方案确定了成年非洲爪蟾的六个器官，展示了对成年非洲爪蟾的心室、肝脏、脂肪体、胰腺、配对肾脏和皮肤的解剖和取样方法。根据保存方法的不同，解剖器官可用于定量蛋白质组学、单细胞/细胞核转录组学、原位杂交、免疫组化、组织学等。该协议旨在标准化组织取样并促进成人器官系统的多实验室研究。

通过使用 图 1 至 图 20 并遵循该协议的所有步骤，心室、肝左叶、胰腺、左脂肪体、成对的肾脏和皮瓣在安乐死后一小时内净地切除。在这段时间内，对样品进行冲洗和修整，使其出现，如图 21 所示。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66489/66489fig1.JPG"> 图 1:...

Watch this Scientific Journal Video about Author Spotlight: Standardizing Tissue Sampling in Proteomics and Immunochemistry Research at JoVE.com

作者聚焦:蛋白质组学和免疫化学研究中的组织采样标准化

本文介绍了在成年 非洲爪蟾 中可以快速轻松地访问的六个重要且多样化的器官样本指南:心室、肝叶、胰腺、脂肪体、成对的肾脏和皮肤。

成年非洲爪蟾六个关键器官快速取样技术

Xenopus has been a powerful model organism for understanding vertebrate development and disease for over a hundred years. While experimental analysis and ...

在这项工作之前，我开发了一种用于快速两栖动物灌注的方案。在取样进行蛋白质组学和免疫化学等研究之前，应使用该协议，在这些研究中，组织中存在过多的血液是不可取的。尽管有许多图表和其他辅助工具可用，但目前还没有关于如何快速可靠地从成年非洲爪蟾中解剖组织的综合指南。我们希望拥有标准化的采样技术将使实验室能够轻松共享组织。在由于生物安全问题或运输限制而无法进出口动物的情况下，这尤其有利。

techniques-for-rapidly-sampling-six-crucial-organs-in-adult-xenopus

Research

JoVE Journal

Biology

Techniques for Rapidly Sampling Six Crucial Organs in Adult Xenopus

813 次观看.  Harvard Medical School. 在这项工作之前，我开发了一种用于快速两栖动物灌注的方案。在取样进行蛋白质组学和免疫化学等研究之前，应使用该协议，在这些研究中，组织中存在过多的血液是不可取的。尽管有许多图表和其他辅助工具可用，但目前还没有关于如何快速可靠地从成年非洲爪蟾中解剖组织的综合指南。我们希望拥有标准化的采样技术将使实验室能够轻松共享组织。在由于生物安?...

视频: 作者聚焦:蛋白质组学和免疫化学研究中的组织采样标准化

Visualizing RNA Localization in Xenopus Oocytes

RNA localization is a conserved mechanism of establishing cell polarity. Vg1 mRNA localizes to the vegetal pole of Xenopus laevis oocytes and acts to spatially restrict gene expression of Vg1 protein. Tight control of Vg1 distribution in this manner is required for proper germ layer specification in the developing embryo. RNA sequence elements in the 3' UTR of the mRNA, the Vg1 localization element (VLE) are required and sufficient to direct transport. To study the recognition and transport of Vg1 mRNA in vivo, we have developed an imaging technique that allows extensive analysis of trans-factor directed transport mechanisms via a simple visual readout. 
To visualize RNA localization, we synthesize fluorescently labeled VLE RNA and microinject this transcript into individual oocytes. After oocyte culture to allow transport of the injected RNA, oocytes are fixed and dehydrated prior to imaging by confocal microscopy. Visualization of mRNA localization patterns provides a readout for monitoring the complete pathway of RNA transport and for identifying roles in directing RNA transport for cis-acting elements within the transcript and trans-acting factors that bind to the VLE (Lewis et al., 2008, Messitt et al., 2008). We have extended this technique through co-localization with additional RNAs and proteins (Gagnon and Mowry, 2009, Messitt et al., 2008), and in combination with disruption of motor proteins and the cytoskeleton (Messitt et al., 2008) to probe mechanisms underlying mRNA localization.

Visualizing RNA Localization in Xenopus Oocytes

Visualization of in vivo RNA transport is accomplished by microinjection of fluorescently labeled RNA transcripts into Xenopus oocytes, followed by confocal microscopy.

可视化的RNA中的本地化爪蟾卵母细胞

RNA localization is a conserved mechanism of establishing cell polarity.  Vg1 mRNA localizes to the vegetal pole of Xenopus laevis oocytes and acts to ...

科研

生物学

Dissection of Organs from the Adult Zebrafish

Over the last 20 years, the zebrafish has become a powerful model organism for understanding vertebrate development and disease.  Although experimental analysis of the embryo and larva is extensive and the morphology has been well documented, descriptions of adult zebrafish anatomy and studies of development of the adult structures and organs, together with techniques for working with adults are lacking. The organs of the larva undergo significant changes in their overall structure, morphology, and anatomical location during the larval to adult transition.  Externally, the transparent larva develops its characteristic adult striped pigment pattern and paired pelvic fins, while internally, the organs undergo massive growth and remodeling.  In addition, the bipotential gonad primordium develops into either testis or ovary.  This protocol identifies many of the organs of the adult and demonstrates methods for dissection of the brain, gonads, gastrointestinal system, heart, and kidney of the adult zebrafish. The dissected organs can be used for in situ hybridization, immunohistochemistry, histology, RNA extraction, protein analysis, and other molecular techniques.  This protocol will assist in the broadening of studies in the zebrafish to include the remodeling of larval organs, the morphogenesis of organs specific to the adult and other investigations of the adult organ systems.

This protocol describes a procedure for identifying and dissecting organs from the adult zebrafish.

剖析器官的成年斑马鱼

Over the last 20 years, the zebrafish has become a powerful model organism for understanding vertebrate development and disease.  Although experimental ...

Techniques for Imaging Ca2+ Signaling in Human Sperm

Fluorescence microscopy of cells loaded with fluorescent, Ca2+-sensitive dyes is used for measurement of spatial and temporal aspects of Ca2+ signaling in live cells. Here we describe the method used in our laboratories for loading suspensions of human sperm with Ca2+-reporting dyes and measuring the fluorescence signal during physiological stimulation. Motile cells are isolated by direct swim-up and incubated under capacitating conditions for 0-24 h, depending upon the experiment. The cell-permeant AM (acetoxy methyl ester) ester form of the Ca2+-reporting dye is then added to a cell aliquot and a period of 1 h is allowed for loading of the dye into the cytoplasm. We use visible wavelength dyes to minimize photo-damage to the cells, but this means that ratiometric recording is not possible. Advantages and disadvantages of this approach are discussed. During the loading period cells are introduced into an imaging chamber and allowed to adhere to a poly-D-lysine coated coverslip. At the end of the loading period excess dye and loose cells are removed by connection of the chamber to the perfusion apparatus. The chamber is perfused continuously, stimuli and modified salines are then added to the perfusion header. Experiments are recorded by time-lapse acquisition of fluorescence images and analyzed in detail offline, by manually drawing regions of interest. Data are normalized to pre-stimulus levels such that, for each cell (or part of a cell), a graph showing the Ca2+ response as % change in fluorescence is obtained.

Techniques for Imaging Ca2+ Signaling in Human Sperm

Stimulus-evoked [Ca2+]i signals of individual human sperm are assessed. Motile cells are loaded with Ca2+-sensitive fluorescent dye (AM-ester method) and immobilised in a perfusable chamber. Cells are imaged by time-lapse fluorescence microscopy and stimulated via the perfusing medium. Responses of single cells (or regions) are analysed offline using Excel.

技术成像钙 2 +信号在人类精子

Fluorescence microscopy of cells loaded with fluorescent, Ca2+-sensitive dyes is used for measurement of spatial and temporal aspects of Ca2+ signaling in ...

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes

The protocol presented here is designed to study the activation of the large conductance, voltage- and Ca2+-activated K+ (BK) channels. The protocol may also be used to study the structure-function relationship for other ion channels and neurotransmitter receptors1. BK channels are widely expressed in different tissues and have been implicated in many physiological functions, including regulation of smooth muscle contraction, frequency tuning of inner hair cells and regulation of neurotransmitter release2-6. BK channels are activated by membrane depolarization and by intracellular Ca2+ and Mg2+ 6-9. Therefore, the protocol is designed to control both the membrane voltage and the intracellular solution. In this protocol, messenger RNA of BK channels is injected into Xenopus laevis oocytes (stage V-VI) followed by 2-5 days of incubation at 18&deg;C10-13. Membrane patches that contain single or multiple BK channels are excised with the inside-out configuration using patch clamp techniques10-13. The intracellular side of the patch is perfused with desired solutions during recording so that the channel activation under different conditions can be examined. To summarize, the mRNA of BK channels is injected into Xenopus laevis oocytes to express channel proteins on the oocyte membrane; patch clamp techniques are used to record currents flowing through the channels under controlled voltage and intracellular solutions.

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes

Ionic current of BK channels is recorded using patch clamp techniques. BK channels are expressed in Xenopus oocytes by injecting messenger RNA. The intracellular solution during patch clamp recordings is controlled by a perfusion system.

膜片钳和灌注技术研究离子通道的表达爪蟾卵母细胞

The protocol presented here is designed to study the activation of the large conductance, voltage- and Ca2+-activated K+ (BK) channels. The protocol may ...

Gavaging Adult Zebrafish

The zebrafish has become an important in vivo model in biomedical research. Effective methods must be developed and utilized to deliver compounds or agents in solutions for scientific research. Current methods for administering compounds orally to adult zebrafish are inaccurate due to variability in voluntary consumption by the fish. A gavage procedure was developed to deliver precise quantities of infectious agents to zebrafish for study in biomedical research. Adult zebrafish over 6 months of age were anesthetized with 150 mg/L of buffered MS-222 and gavaged with 5 &mu;l of solution using flexible catheter implantation tubing attached to a cut 22-G needle tip. The flexible tubing was lowered into the oral cavity of the zebrafish until the tip of the tubing extended past the gills (approximately 1 cm). The solution was then injected slowly into the intestinal tract. This method was effective 88% of the time, with fish recovering uneventfully. This procedure is also efficient as one person can gavage 20-30 fish in one hour. This method can be used to precisely administer agents for infectious diseases studies, or studies of other compounds in adult zebrafish.

The increasing use of zebrafish as an animal model requires the development of effective methods for the delivery of known quantities of compounds and solutions. The gavage procedure described below allows for the oral delivery of precise volumes of solution reliably, safely and efficiently to adult zebrafish.

Gavaging成年斑马鱼

The zebrafish has become an important in vivo model in biomedical research. Effective methods must be developed and utilized to deliver compounds or ...

Facial Transplants in Xenopus laevis Embryos

Craniofacial birth defects occur in 1 out of every 700 live births, but etiology is rarely known due to limited understanding of craniofacial development. To identify where signaling pathways and tissues act during patterning of the developing face, a 'face transplant' technique has been developed in embryos of the frog Xenopus laevis. A region of presumptive facial tissue (the "Extreme Anterior Domain" (EAD)) is removed from a donor embryo at tailbud stage, and transplanted to a host embryo of the same stage, from which the equivalent region has been removed. This can be used to generate a chimeric face where the host or donor tissue has a loss or gain of function in a gene, and/or includes a lineage label. After healing, the outcome of development is monitored, and indicates roles of the signaling pathway within the donor or surrounding host tissues. Xenopus is a valuable model for face development, as the facial region is large and readily accessible for micromanipulation. Many embryos can be assayed, over a short time period since development occurs rapidly. Findings in the frog are relevant to human development, since craniofacial processes appear conserved between Xenopus and mammals.

Facial Transplants in Xenopus laevis Embryos

A technique for transplanting "Extreme Anterior Domain" facial tissue between Xenopus laevis embryos has been developed. Tissue can be moved from one gene expression background into another, allowing the study of local requirements for craniofacial development and for signaling interactions between facial regions.

在面部移植<em&gt;非洲爪蟾</em&gt;胚胎

Craniofacial birth defects occur in 1 out of every 700 live births, but etiology is rarely known due to limited understanding of craniofacial development. ...

The Xenopus Oocyte Cut-open Vaseline Gap Voltage-clamp Technique With Fluorometry

The cut-open oocyte Vaseline gap (COVG) voltage clamp technique allows for analysis of electrophysiological and kinetic properties of heterologous ion channels in oocytes. Recordings from the cut-open setup are particularly useful for resolving low magnitude gating currents, rapid ionic current activation, and deactivation. The main benefits over the two-electrode voltage clamp (TEVC) technique include increased clamp speed, improved signal-to-noise ratio, and the ability to modulate the intracellular and extracellular milieu.
Here, we employ the human cardiac sodium channel (hNaV1.5), expressed in Xenopus oocytes, to demonstrate the cut-open setup and protocol as well as modifications that are required to add voltage clamp fluorometry capability.
The properties of fast activating ion channels, such as hNaV1.5, cannot be fully resolved near room temperature using TEVC, in which the entirety of the oocyte membrane is clamped, making voltage control difficult. However, in the cut-open technique, isolation of only a small portion of the cell membrane allows for the rapid clamping required to accurately record fast kinetics while preventing channel run-down associated with patch clamp techniques.
In conjunction with the COVG technique, ion channel kinetics and electrophysiological properties can be further assayed by using voltage clamp fluorometry, where protein motion is tracked via cysteine conjugation of extracellularly applied fluorophores, insertion of genetically encoded fluorescent proteins, or the incorporation of unnatural amino acids into the region of interest1. This additional data yields kinetic information about voltage-dependent conformational rearrangements of the protein via changes in the microenvironment surrounding the fluorescent molecule.

The Xenopus Oocyte Cut-open Vaseline Gap Voltage-clamp Technique With Fluorometry

The cut-open Vaseline gap approach is used to obtain low noise recordings of ionic and gating currents from voltage-dependent ion channels expressed in Xenopus oocytes with high resolution of fast channel kinetics. With minor modification, voltage clamp fluorometry can be coupled to the cut-open oocyte protocol.

该<em&gt;爪蟾</em&gt;卵母细胞切割开凡士林隙电压钳技术与荧光

The cut-open oocyte Vaseline gap (COVG) voltage clamp technique allows for analysis of electrophysiological and kinetic properties of heterologous ion ...

Reconstitution Of &#946;-catenin Degradation In Xenopus Egg Extract

Xenopus laevis egg extract is a well-characterized, robust system for studying the biochemistry of diverse cellular processes. Xenopus egg extract has been used to study protein turnover in many cellular contexts, including the cell cycle and signal transduction pathways1-3. Herein, a method is described for isolating Xenopus egg extract that has been optimized to promote the degradation of the critical Wnt pathway component, &beta;-catenin. Two different methods are described to assess &beta;-catenin protein degradation in Xenopus egg extract. One method is visually informative ([35S]-radiolabeled proteins), while the other is more readily scaled for high-throughput assays (firefly luciferase-tagged fusion proteins). The techniques described can be used to, but are not limited to, assess &beta;-catenin protein turnover and identify molecular components contributing to its turnover. Additionally, the ability to purify large volumes of homogenous Xenopus egg extract combined with the quantitative and facile readout of luciferase-tagged proteins allows this system to be easily adapted for high-throughput screening for modulators of &beta;-catenin degradation.

Reconstitution Of &#946;-catenin Degradation In Xenopus Egg Extract

A method is described for analyzing protein degradation using radiolabeled and luciferase-fusion proteins in Xenopus egg extract and its adaptation for high-throughput screening for small molecule modulators of protein degradation.

重组β-catenin的降解<em&gt;爪蟾</em&gt;卵提取物

Xenopus laevis egg extract is a well-characterized, robust system for studying the biochemistry of diverse cellular processes. Xenopus egg extract has ...

Non-Terminal Blood Sampling Techniques in Guinea Pigs

Guinea pigs possess several biological similarities to humans and are validated experimental animal models1-3. However, the use of guinea pigs currently represents a relatively narrow area of research and descriptive data on specific methodology is correspondingly scarce. The anatomical features of guinea pigs are slightly different from other rodent models, hence modulation of sampling techniques to accommodate for species-specific differences, e.g., compared to mice and rats, are necessary to obtain sufficient and high quality samples. As both long and short term in vivo studies often require repeated blood sampling the choice of technique should be well considered in order to reduce stress and discomfort in the animals but also to ensure survival as well as compliance with requirements of sample size and accessibility. Venous blood samples can be obtained at a number of sites in guinea pigs e.g., the saphenous and jugular veins, each technique containing both advantages and disadvantages4,5. Here, we present four different blood sampling techniques for either conscious or anaesthetized guinea pigs. The procedures are all non-terminal procedures provided that sample volumes and number of samples do not exceed guidelines for blood collection in laboratory animals6. All the described methods have been thoroughly tested and applied for repeated in vivo blood sampling in studies within our research facility.

Though a known model, the guinea pig currently represents a niche in experimental animal sciences and limited data is available on the execution of most procedures. Here we present four different approaches to non-terminal in vivo blood sampling techniques in either conscious or anaesthetized guinea pigs.

豚鼠非终端采血技术

Guinea pigs possess several biological similarities to humans and are validated experimental animal models1-3. However, the use of guinea pigs currently ...

Quantification of Orofacial Phenotypes in Xenopus

Xenopus has become an important tool for dissecting the mechanisms governing craniofacial development and defects. A method to quantify orofacial development will allow for more rigorous analysis of orofacial phenotypes upon abrogation with substances that can genetically or molecularly manipulate gene expression or protein function. Using two dimensional images of the embryonic heads, traditional size dimensions-such as orofacial width, height and area- are measured. In addition, a roundness measure of the embryonic mouth opening is used to describe the shape of the mouth. Geometric morphometrics of these two dimensional images is also performed to provide a more sophisticated view of changes in the shape of the orofacial region. Landmarks are assigned to specific points in the orofacial region and coordinates are created. A principle component analysis is used to reduce landmark coordinates to principle components that then discriminate the treatment groups. These results are displayed as a scatter plot in which individuals with similar orofacial shapes cluster together. It is also useful to perform a discriminant function analysis, which statistically compares the positions of the landmarks between two treatment groups. This analysis is displayed on a transformation grid where changes in landmark position are viewed as vectors. A grid is superimposed on these vectors so that a warping pattern is displayed to show where significant landmark positions have changed. Shape changes in the discriminant function analysis are based on a statistical measure, and therefore can be evaluated by a p-value. This analysis is simple and accessible, requiring only a stereoscope and freeware software, and thus will be a valuable research and teaching resource.

Quantification of Orofacial Phenotypes in Xenopus

A method to quantify the orofacial size and shape of Xenopus laevis embryos has been developed. In this protocol, traditional size measurements are combined with geometric morphometrics to allow for more sophisticated analyses of orofacial development and defects.