我们感谢生命科学与艺术和科学学院在皇后大学为这项工作提供资金。同时，我们感谢钦生实验室提供必要的试剂，设备和技术支持。我们也感谢2011年QGEM，尤其是托尼，他为他的贡献的讨论。

1。准备/洗涤蠕虫<ol><li>同步蠕虫年轻成人11。 </li><li>吸取2毫升到5厘米的趋化板的S基础上演OP50 E.刚刚清除草坪蠕虫大肠杆菌 。倾斜板，根据需要，以确保到缓冲区中的板面从洗涤蠕虫。 </li><li>吸取1毫升离心管蠕虫-S基础的解决方案。 </li><li> ，持续10秒使用PicoFuge，在6,600 rpm转速下离心。 </li><li>吸的S基础，离开颗粒蠕虫不受干扰的。 </li><li> ML小号基础的解决方案添加到离心管中，颠倒几次洗蠕虫。 </li><li>重复步骤1.4〜1.6另外三次。 </li><li>离心的第五时间，这段时间吸取上清液，至终体积为约10秒。 100微升。 </li><li>取2微升到NGM板，以确保各2微升样品中，有50和250之间的蠕虫的蠕虫。调整根据需要通过重悬体积更小或更大的S基底中的蠕虫的蠕虫在S基底的浓度。 </li><li>使用后立即洗了长达1小时的蠕虫蠕虫检测。 </li></ol> 2。准备测试板<ol><li>标志着一个5厘米的板的底面，分为4象限划分的菜。趋化琼脂或NGM的也可使用。需要最少3个试验正在测试每遗传应变。 </li><li>马克的圆的半径为0.5厘米的原点周围（ 图1）。 </li><li>使用一个“T”为“测试”或“C”为“控制”，确保该网站是等距离的起源和相互点标记在每个象限。点必须远离原点至少2厘米。马克左上角和右下角的象限作为测试象限的右上方和左下象限作为对照（ 图1）。 </li></ol> 3。运行试验</P&gt; <ol><li>相结合的试验化合物和0.5M磷酰基叠氮化物（麻醉剂使用逮捕的蠕虫在到达一个象限）的等体积混合供试品溶液。混合控制解决方案相结合，所用的溶剂稀释试验化合物用0.5 M的叠氮化物。 </li><li>吸取2μl的蠕虫溶液（1.8）编制沉淀到原点（两线相交）。 </li><li>紧接着吸管2微升的两个“T”网站上的测试解决方案。同样地，移液管的控制解决方案的相同数量的两个“C”的网站上。 </li><li>一旦蠕虫和嗅觉下降已在琼脂吸收，更换盖子，翻转板。 </li><li> 60分钟后，将蠕虫病毒在4℃培养箱。只有从孵化器中取出板时，它可以算作。离开蠕虫在室温下，可能让他们再次动员。 </li><li>记录每一个象限中的蠕虫数目，完全越过内保监会文件中。 </li><li>重复使用控制解决方案在测试和控制象限步骤3.2至3.6。这将作为控制板。三板应该和运行服务作为一个适当的控制。 </li></ol> 4。解读比分/确定趋化指数<ol><li>使用公式1计算趋化指数。这将产生一个趋化指数-1.0和+1.0之间。 </li></ol> （1） 趋化指数=（＃蠕虫在两个测试象限 - ＃蠕虫两个控制象限）/（总进球蠕虫） 1.0的比分实现的目标，并表示最大的吸引力，蠕虫抵达含有化学目标象限代表100％。指数-1.0最大排斥的证据。类似的检测方法已经被聘用3名（ 见表1）。 <ol start="2"><li>报告平均ChemotaxiS指数（CI）和标准误差（SEM）。执行一个Student T检验比较的数据，从试验组和对照板。 </li></ol>

<ol>
	<li>Bargmann, C. I., Hartwieg, E., Horvitz, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorant-selective+genes+and+neurons+mediate+olfaction+in+C.+elegans.">Odorant-selective genes and neurons mediate olfaction in C. elegans.</a> Cell. 74, 515-527 (1993).</li><li>Bargmann, C. I., Horvitz, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemosensory+neurons+with+overlapping+functions+direct+chemotaxis+to+multiple+chemicals+in+C.+elegans.">Chemosensory neurons with overlapping functions direct chemotaxis to multiple chemicals in C. elegans.</a> Neuron. 7, 729-742 (1991).</li><li>Lee, J., Jee, C., McIntire, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethanol+preference+in+C.+elegans.">Ethanol preference in C. elegans.</a> Genes Brain Behav. 8, 578-585 (2009).</li><li>Swierczek, N. A., Giles, A. C., Rankin, C. H., Kerr, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+behavioral+analysis+in+C.+elegans.">High-throughput behavioral analysis in C. elegans.</a> Nat. Methods. 8, 592-598 (2011).</li><li>Ward, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotaxis+by+the+nematode+Caenorhabditis+elegans:+identification+of+attractants+and+analysis+of+the+response+by+use+of+mutants.">Chemotaxis by the nematode Caenorhabditis elegans: identification of attractants and analysis of the response by use of mutants.</a> Proc. Natl. Acad. Sci. U.S.A. 70, 817-821 (1973).</li><li>Colbert, H. A., Bargmann, C. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorant-specific+adaptation+pathways+generate+olfactory+plasticity+in+C.+elegans.">Odorant-specific adaptation pathways generate olfactory plasticity in C. elegans.</a> Neuron. 14, 803-812 (1995).</li><li>Kauffman, A., Parsons, L., Stein, G., Wills, A., Kaletsky, R., Murphy, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=C.+elegans+Positive+Butanone+Learning,+Short-term,+and+Long-term+Associative+Memory+Assays.">C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays.</a> J. Vis. Exp. (49), e2490 (2011).</li><li>Troemel, E. R., Kimmel, B. E., Bargmann, C. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reprogramming+chemotaxis+responses:+sensory+neurons+define+olfactory+preferences+in+C.+elegans.">Reprogramming chemotaxis responses: sensory neurons define olfactory preferences in C. elegans.</a> Cell. 91, 161-169 (1997).</li><li>Pierce-Shimomura, J. T., Morse, T. M., Lockery, 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=The+fundamental+role+of+pirouettes+in+Caenorhabditis+elegans+chemotaxis.">The fundamental role of pirouettes in Caenorhabditis elegans chemotaxis.</a> J Neurosci. 19, 9557-9569 (1999).</li><li>Frokjaer-Jensen, C., Ailion, M., Lockery, 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=Ammonium-acetate+is+sensed+by+gustatory+and+olfactory+neurons+in+Caenorhabditis+elegans.">Ammonium-acetate is sensed by gustatory and olfactory neurons in Caenorhabditis elegans.</a> PLoS One. 3, e2467 (2008).</li><li>Porta-de-la-Riva, M., Fontrodona, L., Villanueva, A., Cer&#243;n, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basic+Caenorhabditis+elegans+Methods:+Synchronization+and+Observation.">Basic Caenorhabditis elegans Methods: Synchronization and Observation.</a> J. Vis. Exp. (64), e4019 (2012).</li><li>Sengupta, P., Bargmann, C. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+fate+specification+and+differentiation+in+the+nervous+system+of+Caenorhabditis+elegans.">Cell fate specification and differentiation in the nervous system of Caenorhabditis elegans.</a> Dev. Genet. 18, 73-80 (1996).</li><li>Hart, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavior.">Behavior.</a> WormBook. , (1895).</li></ol>

我们什么都没有透露。

趋化，虽然控制的一组复杂的神经元和细胞机制，能够容易且客观的定量使用趋化实验。为了获得最佳的检测结果，必须采取某些关键步骤。首先，举办蠕虫产生一致的实验结果是必不可少的。蠕虫在不同的人生阶段有不同的行为13，所以混合阶段蠕虫可能会歪斜实验结果。其次，确保所有E.大肠杆菌洗掉的蠕虫是至关重要的，因为残留的细菌可能会干扰检测。同样重要的是，要注?...

沃德第一次在1973年5开发的趋化实验，并从那时起，它有深远的应用。神经生物学是一个领域，受惠于使用各种趋化实验。 C.嗅觉适应，学习和记忆的一种简单形式，已被证明在线虫趋化实验6。它们也被用来表明C。线虫可以开发乙醇耐受性的结果不仅展现了蠕虫的行为可塑性，但也表明，蠕虫可以是非常有用的，在研究酒精依赖人类3。检测甚至已经发展到展示的能力C.线虫短期和长期记忆存储协会是由趋化因子之间的蠕虫和食品（OP50）7。此外，由于广泛的信息，目前有关C.线虫基因组，chemotaxiC.行为已经改变了无数次的线虫进行基因突变1,8。这使得许多令人兴奋的工程的可能性，如发展C.线虫作为一个生物修复工具。因此，在1973年以来的初步发展的趋化实验，已经频繁地改变，用来阐明多种学科的奥秘。 某些实验旨在发现蠕虫朝着一个目标所采取的具体路线。这种原型试验是由沃德5。三虫熔化的琼脂上放置15分钟。他们的运动跟踪它们留下的印记，因为他们从一个梯度板在板的中心引诱的周边。盘上的所有蠕虫病毒被逮捕用氯仿在每次试验结束。这种方法的一个后裔在板中间放置一个单一的蠕虫的引诱和控制从原点2吨的距离相等，方向相反。 皮尔斯下村等 。开发了一个试验，以观察在趋化9所涉及的移动的确切性质。个人蠕虫放置在9厘米的培养皿中可以含有引诱剂或径向形状的梯度均匀的浓度，最终在源的引诱剂。确认该蠕虫的计算机软件程序，是用来记录所观察到的行为。一种摄像机连接到显微镜一起工作的阶段来调整培养皿中，自动检测运行，以确保保持在视场中的蠕虫。由此看来，更详细的信息被发现的原因下所显示的回旋线虫 。 其他检测，更类似于此处所述，测试一个人口众多的蠕虫病毒测试化合物的反应。二象限趋化实验已经用于探索各种神经细胞，受体和信号转导分子的角色时播放C.线虫暴露于各种化合物1。 20-50之间水洗蠕虫被放置在板的中心附近与引诱剂，麻醉剂，叠氮化钠（NaN 3的）一起在极性端和一个控制。 60分钟后，趋化指数值从-1.0到1.0，产生多少蠕虫贴的引诱剂或控制之间的差异的基础上。类似的趋化指数是用于测定在这篇文章中报道，虽然未能严格评估非能动的蠕虫早期检测。此法进一步趋化测试神经消融的影响。 进行上述测定法的另一种变化，其中含有四个象限3的板的中心被放置在100-200蠕虫。相邻象限包含测试或控制物质。在以前的实验中，蠕虫叠氮化钠的作用被固定之前被拿下。这里描述的类似的方法作为一种评价的反应C.线虫的各种化合物。但是，下面的方法有额外的好处，仅评估已通过阈值距离分离手机动的蠕虫蠕虫。 其他实验已纳入忽略不动的蠕虫类似指引。 frøkjær-Jensen 等 。开发出一种通用的检测，可以用来测试易失性和水溶性化合物10。培养皿分为四个象限。顶部和底部的象限内不含有溶剂。左象限包含水，以及所载的权利，引诱剂。测试时，挥发性的气味中，分析物被放置在盖子上的菜，在适当的象限，而水溶性化合物被直接放置在琼脂糖河目前存在一种方法，用于评估下的趋化反应线虫正在不断地被改进，以优化其便于使用，效率和准确性。所以，虽然这里描述的检测有能力评估的最大数量的蠕虫（最大吞吐量：250的蠕虫/小时每板，略大于由Lee 等人表现出的吞吐量）;这种方法是真正的实力简洁的高潮许多早期检测（ 表1）的属性。

<table border="1">
 <tbody>
 <tr>
 <td>Name of Reagent/Material</td>
 <td>Company</td>
 <td>Catalogue Number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>S Basal (- cholesterol) [5.8 g NaCl; 1 M K phosphate buffer, pH 6.0; dH2O to 1 liter.] Autoclave</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>PicoFuge</td>
 <td>Stratagene</td>
 <td>400552</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Microscopes</td>
 <td>Leica</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Dissecting</td>
 <td>Leica</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>P1000 Pipette</td>
 <td>Gilson</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>P10 Pipette</td>
 <td>Gilson</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>0.5 M Sodium Azide</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Chemotaxis Agar [1.6% BBL-agar (Benton-Dickinson) or 2% Difco-agar. Autoclave. Add 5 mM potassium phosphate, pH 6.0; 1 mM CaCl2, 1 mM MgSO4]</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Ethanol/Distilled Water</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Test Compounds (eg. 0.5% diacetyl)</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Agar</td>
 <td>Bio-Rad</td>
 <td>166-0600</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>NH4Cl</td>
 <td>Amresco</td>
 <td>CA97062-046</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>MOPS</td>
 <td>VWR</td>
 <td>CA12001-120</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>NH4OH</td>
 <td>BDH</td>
 <td>CABDH8641-2</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>0.25% Tween 20</td>
 <td>Bio-Rad</td>
 <td>170-6531</td>
 <td>&nbsp;</td>
 </tr>
 </tbody>
</table>

c. elegans chemotaxis assay

许多生物都使用趋化寻求食物来源，避免有毒物质，并寻找配偶。 线虫具有令人印象深刻的趋化行为。 后面测试蠕虫的加臭剂的反应的前提是将它们放置在一个区域，并观察响应的加臭剂诱发的运动。即使有许多可用的检测，优化蜗杆相对于起始位置的控 ​​制和测试区，同时最大限度地减少与对方，同时保持了显着的样本大小的相互作用蠕虫仍然正在进行中的1-10项的工作。这里描述的方法的目的是为解决这些问题，通过修改巴格曼等人开发的测定。甲培养皿分为四个象限，两个相对的象限标记为“测试”和两个被指定为“控制”。麻醉是摆在所有的测试和控制的网站。蠕虫放置在板的中心与精华É围绕原点标记，以确保非能动的蠕虫将被忽略。利用一个四象限系统，而不是一个或两个1消除偏置蠕虫的运动，因为它们是从试验组和对照样品的距离相等，而不管他们开始的哪一侧的起源。这就避免蠕虫被迫穿越其他蠕虫的集群，以应对气味，可延缓蠕虫或迫使他们采取更迂回的路线，其拟定的路径产生一个不正确的解释的问题。这种方法也显示了实用的优点，具有较大样本的大小和允许研究员无人值守运行分析和得分蠕虫一旦在规定的时间已过期。

比较野生型（N2）C. ODR-10（KY10）突变的线虫 。 我们使用的丁二酮，公知的C。线虫趋化双乙酰1,12缺乏受体的突变，比较野生型蠕虫。对于野生型（N2）蠕虫的趋化指数为（0.100±0.066）乙醇和0.839±0.031至0.5％的二乙酰。正如预期的那样，二乙酰引出一个显着chemoattractive的野生型蠕虫（P &lt;0.003）的响应。与此相反，在ODR-10（KY10）突变体缺?...

Watch this Scientific Journal Video about C. elegans Chemotaxis Assay at JoVE.com

C. elegans Chemotaxis Assay

定量评价的趋化反应的方法<em&gt;线虫</em&gt;进行说明。趋化指数（CI）作为一种能够精确地评估蠕虫的反应到一定的目标，并作为一个平台之间的比较利益的菌株和化合物。

线虫趋含量的

Many organisms use chemotaxis to seek out food sources, avoid noxious substances, and find mates.  Caenorhabditis elegans has impressive chemotaxis ...

Research

JoVE Journal

Biology

C. elegans Chemotaxis Assay

45.0K 次观看.  Queen's University. 定量评价的趋化反应的方法线虫进行说明。趋化指数（CI）作为一种能够精确地评估蠕虫的反应到一定的目标，并作为一个平台之间的比较利益的菌株和化合物。

视频: C. elegans Chemotaxis Assay

Generation of Stable Transgenic C. elegans Using Microinjection

Transgenic Caenorhabditis elegans can be readily created via microinjection of a DNA plasmid solution into the gonad 1. The plasmid DNA rearranges to form extrachromosomal concatamers that are stably inherited, though not with the same efficiency as actual chromosomes 2. A gene of interest is co-injected with an obvious phenotypic marker, such as rol-6 or GFP, to allow selection of transgenic animals under a dissecting microscope. The exogenous gene may be expressed from its native promoter for cellular localization studies. Alternatively, the transgene can be driven by a different tissue-specific promoter to assess the role of the gene product in that particular cell or tissue. This technique efficiently drives gene expression in all tissues of C. elegans except for the germline or early embryo 3. Creation of transgenic animals is widely utilized for a range of experimental paradigms. This video demonstrates the microinjection procedure to generate transgenic worms. Furthermore, selection and maintenance of stable transgenic C. elegans lines is described.

This video demonstrates the technique of microinjection into the gonad of C. elegans to create transgenic animals.

产生稳定的转基因C.使用微量注射线虫

Transgenic Caenorhabditis elegans can be readily created via microinjection of a DNA plasmid solution into the gonad 1.  The plasmid DNA rearranges to ...

科研

生物学

Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson's Disease Genes

Improvements to the diagnosis and treatment of Parkinson's disease (PD) are dependent upon knowledge about susceptibility factors that render populations at risk. In the process of attempting to identify novel genetic factors associated with PD, scientists have generated many lists of candidate genes, polymorphisms, and proteins that represent important advances, but these leads remain mechanistically undefined. Our work is aimed toward significantly narrowing such lists by exploiting the advantages of a simple animal model system. While humans have billions of neurons, the microscopic roundworm Caenorhabditis elegans has precisely 302, of which only eight produce dopamine (DA) in hemaphrodites. Expression of a human gene encoding the PD-associated protein, alpha-synuclein, in C. elegans DA neurons results in dosage and age-dependent neurodegeneration.
Worms expressing human alpha-synuclein in DA neurons are isogenic and express both GFP and human alpha-synuclein under the DA transporter promoter (Pdat-1). The presence of GFP serves as a readily visualized marker for following DA neurodegeneration in these animals. We initially demonstrated that alpha-synuclein-induced DA neurodegeneration could be rescued in these animals by torsinA, a protein with molecular chaperone activity 1. Further, candidate PD-related genes identified in our lab via large-scale RNAi screening efforts using an alpha-synuclein misfolding assay were then over-expressed in C. elegans DA neurons. We determined that five of seven genes tested represented significant candidate modulators of PD as they rescued alpha-synuclein-induced DA neurodegeneration 2. Additionally, the Lindquist Lab (this issue of JoVE) has performed yeast screens whereby alpha-synuclein-dependent toxicity is used as a readout for genes that can enhance or suppress cytotoxicity. We subsequently examined the yeast candidate genes in our C. elegans alpha-synuclein-induced neurodegeneration assay and successfully validated many of these targets 3, 4.
Our methodology involves generation of a C. elegans DA neuron-specific expression vector using recombinational cloning of candidate gene cDNAs under control of the Pdat-1 promoter. These plasmids are then microinjected in wild-type (N2) worms, along with a selectable marker for successful transformation. Multiple stable transgenic lines producing the candidate protein in DA neurons are obtained and then independently crossed into the alpha-synuclein degenerative strain and assessed for neurodegeneration, at both the animal and individual neuron level, over the course of aging.

Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson&#039;s Disease Genes

This video demonstrates how to use C. elegans to assess dopaminergic neuron neurodegeneration as a model for Parkinson's disease. Furthermore, genetic screens are used to identify factors that either enhance degeneration or are neuroprotective.

一个线虫多巴胺神经元退化含量的应用验证潜在的帕金森氏症基因

Improvements to the diagnosis and treatment of Parkinson's disease (PD) are dependent upon knowledge about susceptibility factors that render populations ...

Paradigms for Pharmacological Characterization of C. elegans Synaptic Transmission Mutants

The nematode, Caenorhabditis elegans, has become an expedient model for studying neurotransmission. C. elegans is unique among animal models, as the anatomy and connectivity of its nervous system has been determined from electron micrographs and refined by pharmacological assays. In this video, we describe how two complementary neural stimulants, an acetylcholinesterase inhibitor, called aldicarb, and a gamma-aminobutyric acid (GABA) receptor antagonist, called pentylenetetrazole (PTZ), may be employed to specifically characterize signaling at C. elegans neuromuscular junctions (NMJs) and facilitate our understanding of antagonistic neural circuits.
Of 302 C. elegans neurons, nineteen GABAergic D-type motor neurons innervate body wall muscles (BWMs), while four GABAergic neurons, called RMEs, innervate head muscles. Conversely, thirty-nine motor neurons express the excitatory neurotransmitter, acetylcholine (ACh), and antagonize GABA transmission at BWMs to coordinate locomotion. The antagonistic nature of GABAergic and cholinergic motor neurons at body wall NMJs was initially determined by laser ablation and later buttressed by aldicarb exposure. Acute aldicarb exposure results in a time-course or dose-responsive paralysis in wild-type worms. Yet, loss of excitatory ACh transmission confers resistance to aldicarb, as less ACh accumulates at worm NMJs, leading to less stimulation of BWMs. Resistance to aldicarb may be observed with ACh-specific or general synaptic function mutants. Consistent with antagonistic GABA and ACh transmission, loss of GABA transmission, or a failure to negatively regulate ACh release, confers hypersensitivity to aldicarb. Although aldicarb exposure has led to the isolation of numerous worm homologs of neurotransmission genes, aldicarb exposure alone cannot efficiently determine prevailing roles for genes and pathways in specific C. elegans motor neurons. For this purpose, we have introduced a complementary experimental approach, which uses PTZ.
Neurotransmission mutants display clear phenotypes, distinct from aldicarb-induced paralysis, in response to PTZ. Wild-type worms, as well as mutants with specific inabilities to release or receive ACh, do not show apparent sensitivity to PTZ. However, GABA mutants, as well as general synaptic function mutants, display anterior convulsions in a time-course or dose-responsive manner. Mutants that cannot negatively regulate general neurotransmitter release and, thus, secrete excessive amounts of ACh onto BWMs, become paralyzed on PTZ. The PTZ-induced phenotypes of discrete mutant classes indicate that a complementary approach with aldicarb and PTZ exposure paradigms in C. elegans may accelerate our understanding of neurotransmission. Moreover, videos demonstrating how we perform pharmacological assays should establish consistent methods for C. elegans research.

This video demonstrates how to employ two neural stimulants, aldicarb and pentylenetetrazole (PTZ), in complementary ways to study synaptic function in the nematode, C. elegans. This complementary approach may also be used to shed light on evolutionarily conserved mechanisms for modulating neuronal synchrony and has implications for epilepsy and seizures.

为线虫突触传递的突变体的药理特性的范式

The nematode, Caenorhabditis elegans, has become an expedient model for studying neurotransmission. C. elegans is unique among animal models, as the ...

Dissecting and Recording from The C. Elegans Neuromuscular Junction

Neurotransmission is the process by which neurons transfer information via chemical signals to their post-synaptic targets, on a rapid time scale. This complex process requires the coordinated activity of many pre- and post-synaptic proteins to ensure appropriate synaptic connectivity, conduction of electrical signals, targeting and priming of secretory vesicles, calcium sensing, vesicle fusion, localization and function of postsynaptic receptors and finally, recycling mechanisms. As neuroscientists it is our goal to elucidate which proteins function in each of these steps and understand their mechanisms of action. Electrophysiological recordings from synapses provide a quantifiable read out of the underlying electrical events that occur during synaptic transmission. By combining this technique with the powerful array of molecular and genetic tools available to manipulate synaptic proteins in C. elegans, we can analyze the resulting functional changes in synaptic transmission. 
The C. elegans NMJs formed between motor neurons and body wall muscles control locomotion, therefore, mutants with uncoordinated locomotory phenotypes (known as unc s) often perturb synaptic transmission at these synapses 1. Since unc mutants are maintained on a rich supply of a bacterial food source, they remain viable as long as they retain some pharyngeal pumping ability to ingest food. This, together with the fact that C. elegans exist as hermaphrodites, allows them to pass on mutant progeny without the need for elaborate mating behaviors. These attributes, coupled with our recent ability to record from the worms NMJs 2,3,7 make this an excellent model organism in which to address precisely how unc mutants impact neurotransmission. 
The dissection method involves immobilizing adult worms using a cyanoacrylic glue in order to make an incision in the worm cuticle exposing the NMJs. Since C. elegans adults are only 1 mm in length the dissection is performed with the use of a dissecting microscope and requires excellent hand-eye coordination. NMJ recordings are made by whole-cell voltage clamping individual body wall muscle cells and neurotransmitter release can be evoked using a variety of stimulation protocols including electrical stimulation, light-activated channel-rhodopsin-mediated depolarization 4 and hyperosmotic saline, all of which will be briefly described.

Application of electrophysiology to accessible synapses provides a quantifiable measure of synaptic activity, useful in analyzing synaptic mutants. This article describes a dissection method used to expose the neuromuscular junctions (NMJ) of Caenorhabditis elegans (C. elegans) and briefly discusses some of the uses to which this preparation can be applied.

线虫神经肌肉交界处的解剖和录制

Neurotransmission is the process by which neurons transfer information via chemical signals to their post-synaptic targets, on a rapid time scale.   This ...

Generation of Transgenic C. elegans by Biolistic Transformation

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid generation time and short life span, easy and inexpensive maintenance, fully sequenced genome, and array of RNAi resources and mutant animals. Additionally, analysis of the C. elegans genome revealed a great similarity between worms and higher vertebrates, which suggests that research in worms could be an important adjunct to studies performed in whole mice or cultured cells. A powerful and important part of worm research is the ability to use transgenic animals to study gene localization and function. Transgenic animals can be created either via microinjection of the worm germline or through the use of biolistic bombardment. Bombardment is a newer technique and is less familiar to a number of labs. Here we describe a simple protocol to generate transgenic worms by biolistic bombardment with gold particles using the Bio-Rad PDS-1000 system. Compared with DNA microinjection into hermaphrodite germline, this protocol has the advantage of not requiring special skills from the operator with regards to identifying worm anatomy or performing microinjection. Further multiple transgenic lines are usually obtained from a single bombardment. Also in contrast to microinjection, biolistic bombardment produces transgenic animals with both extrachromosomal arrays and integrated transgenes. The ability to obtain integrated transgenic lines can avoid the use of mutagenic protocols to integrate foreign DNA. In conclusion, biolistic bombardment can be an attractive method for the generation of transgenic animals, especially for investigators not interested in investing the time and effort needed to become skilled at microinjection.

Generation of Transgenic C. elegans by Biolistic Transformation

Transgenic worms are commonly used in C. elegans research. Described is a simple, yet effective, protocol to introduce transgenes into worms using biolistic bombardment with DNA-coated gold particles. The effort involved and results of bombardment compare favorably with microinjection for the generation of transgenic animals.

生成的基因 C。线虫通过基因枪转化

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid ...

RNAi Screening to Identify Postembryonic Phenotypes in C. elegans

C. elegans has proven to be a valuable model system for the discovery and functional characterization of many genes and gene pathways1. More sophisticated tools and resources for studies in this system are facilitating continued discovery of genes with more subtle phenotypes or roles. 
Here we present a generalized protocol we adapted for identifying C. elegans genes with postembryonic phenotypes of interest using RNAi2. This procedure is easily modified to assay the phenotype of choice, whether by light or fluorescence optics on a dissecting or compound microscope. This screening protocol capitalizes on the physical assets of the organism and molecular tools the C. elegans research community has produced. As an example, we demonstrate the use of an integrated transgene that expresses a fluorescent product in an RNAi screen to identify genes required for the normal localization of this product in late stage larvae and adults. First, we used a commercially available genomic RNAi library with full-length cDNA inserts. This library facilitates the rapid identification of multiple candidates by RNAi reduction of the candidate gene product. Second, we generated an integrated transgene that expresses our fluorecently tagged protein of interest in an RNAi-sensitive background. Third, by exposing hatched animals to RNAi, this screen permits identification of gene products that have a vital embryonic role that would otherwise mask a post-embryonic role in regulating the protein of interest. Lastly, this screen uses a compound microscope equipped for single cell resolution.

RNAi Screening to Identify Postembryonic Phenotypes in C. elegans

We describe a sensitized method to identify postembryonic regulators of protein expression and localization in C. elegans using an RNAi-based genomic screen and an integrated transgene that expresses a functional, fluorescently tagged protein.

RNAi筛选识别胚后的表型 C。线虫</em

C. elegans has proven to be a valuable model system for the discovery and functional characterization of many genes and gene pathways1. More sophisticated ...

Basic Caenorhabditis elegans Methods: Synchronization and Observation

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has since been used extensively as a model organism 1. C. elegans possesses key attributes such as simplicity, transparency and short life cycle that have made it a suitable experimental system for fundamental biological studies for many years 2. Discoveries in this nematode have broad implications because many cellular and molecular processes that control animal development are evolutionary conserved 3.
C. elegans life cycle goes through an embryonic stage and four larval stages before animals reach adulthood. Development can take 2 to 4 days depending on the temperature. In each of the stages several characteristic traits can be observed. The knowledge of its complete cell lineage 4,5 together with the deep annotation of its genome turn this nematode into a great model in fields as diverse as the neurobiology 6, aging 7,8, stem cell biology 9 and germ line biology 10. 
An additional feature that makes C. elegans an attractive model to work with is the possibility of obtaining populations of worms synchronized at a specific stage through a relatively easy protocol. The ease of maintaining and propagating this nematode added to the possibility of synchronization provide a powerful tool to obtain large amounts of worms, which can be used for a wide variety of small or high-throughput experiments such as RNAi screens, microarrays, massive sequencing, immunoblot or in situ hybridization, among others. 
Because of its transparency, C. elegans structures can be distinguished under the microscope using Differential Interference Contrast microscopy, also known as Nomarski microscopy. The use of a fluorescent DNA binder, DAPI (4',6-diamidino-2-phenylindole), for instance, can lead to the specific identification and localization of individual cells, as well as subcellular structures/defects associated to them.

Basic Caenorhabditis elegans Methods: Synchronization and Observation

The easiness of maintaining and propagating the nematode C. elegans make it a nice model organism to work with. The possibility of synchronizing worms allows the work with a significant amount of subjects at the same developmental stage, what facilitates the study of one particular process in many animals.

基本的<em&gt;线虫</em&gt;方法：同步和观察

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has ...

A Method for Culturing Embryonic C. elegans Cells

C. elegans is a powerful model system, in which genetic and molecular techniques are easily applicable. Until recently though, techniques that require direct access to cells and isolation of specific cell types, could not be applied in C. elegans. This limitation was due to the fact that tissues are confined within a pressurized cuticle which is not easily digested by treatment with enzymes and/or detergents. Based on early pioneer work by Laird Bloom, Christensen and colleagues 1 developed a robust method for culturing C. elegans embryonic cells in large scale. Eggs are isolated from gravid adults by treatment with bleach/NaOH and subsequently treated with chitinase to remove the eggshells. Embryonic cells are then dissociated by manual pipetting and plated onto substrate-covered glass in serum-enriched media. Within 24 hr of isolation cells begin to differentiate by changing morphology and by expressing cell specific markers. C. elegans cells cultured using this method survive for up 2 weeks in vitro and have been used for electrophysiological, immunochemical, and imaging analyses as well as they have been sorted and used for microarray profiling.

A Method for Culturing Embryonic C. elegans Cells

We describe here a revised protocol for large-scale culture of embryonic C. elegans cells. Embryonic C. elegans cells cultured in vitro using this method, appear to differentiate and recapitulate the expression of genes in a cell specific manner. Techniques that require direct access to the cells or isolation of specific cell types from the other tissues can be applied on C. elegans cultured cells.

一种用于培养胚胎<em&gt; C。线虫</em&gt;细胞

C. elegans is a powerful model system, in which genetic and molecular techniques are easily applicable. Until recently though, techniques that require ...

Antibody Staining in C. Elegans Using &quot;Freeze-Cracking&quot;

To stain C. elegans with antibodies, the relatively impermeable cuticle must be bypassed by chemical or mechanical methods. "Freeze-cracking" is one method used to physically pull the cuticle from nematodes by compressing nematodes between two adherent slides, freezing them, and pulling the slides apart. Freeze-cracking provides a simple and rapid way to gain access to the tissues without chemical treatment and can be used with a variety of fixatives. However, it leads to the loss of many of the specimens and the required compression mechanically distorts the sample. Practice is required to maximize recovery of samples with good morphology. Freeze-cracking can be optimized for specific fixation conditions, recovery of samples, or low non-specific staining, but not for all parameters at once. For antibodies that require very hard fixation conditions and tolerate the chemical treatments needed to chemically permeabilize the cuticle, treatment of intact nematodes in solution may be preferred. If the antibody requires a lighter fix or if the optimum fixation conditions are unknown, freeze-cracking provides a very useful way to rapidly assay the antibody and can yield specific subcellular and cellular localization information for the antigen of interest.

Antibody Staining in C. Elegans Using &quot;Freeze-Cracking&quot;

"Freeze-cracking," a method for exposing the inner tissues of the nematode C. elegans to antibodies for protein localization, is demonstrated.

抗体在染色<em&gt; C。线虫</em&gt;使用“冻结开裂”

To stain C.  elegans with antibodies, the relatively impermeable cuticle must be  bypassed by chemical or mechanical methods.  "Freeze-cracking" is one ...

Measuring the Effects of Bacteria on C. Elegans Behavior Using an Egg Retention Assay

C. elegans egg-laying behavior is affected by environmental cues such as osmolarity1 and vibration2. In the total absence of food C. elegans also cease egg-laying and retain fertilized eggs in their uterus3. However, the effect of different sources of food, especially pathogenic bacteria and particularly Enterococcus faecalis, on egg-laying
	behavior is not well characterized. The egg-in-worm (EIW) assay is a useful tool to quantify the effects of different types of bacteria, in this case E. faecalis, on egg- laying behavior.
	
	EIW assays involve counting the number of eggs retained in the uterus of C. elegans4. The EIW assay involves bleaching staged, gravid adult C. elegans to remove the cuticle and separate the retained eggs from the animal. Prior to bleaching, worms are exposed to bacteria (or any type of environmental cue) for a fixed period of time. After bleaching, one is very easily able to count the number of eggs retained inside the uterus of the worms. In this assay, a quantifiable increase in egg retention after E. faecalis exposure can be easily measured. The EIW assay is a behavioral assay that may be used to screen for potentially pathogenic bacteria or the presence of environmental toxins. In addition, the EIW assay may be a tool to screen for drugs that affect neurotransmitter signaling since egg-laying behavior is modulated by neurotransmitters such as serotonin and acetylcholine5-9.

Measuring the Effects of Bacteria on C. Elegans Behavior Using an Egg Retention Assay

An egg-in-worm (EIW) assay is a useful method to quantify egg-laying behavior. Alterations in egg laying can be a behavioral response of the model organism Caenorhabditis elegans to potentially harmful environmental substances such as those produced by pathogenic bacteria.

测量细菌的影响<em&gt; C。线虫</em&gt;行为使用一个鸡蛋保留含量

C. elegans egg-laying behavior is  affected by environmental cues such as osmolarity1 and  vibration2. In the total absence of food C. elegans also cease ...