这项工作得到了斯洛文尼亚的研究机构（项目J2 - 9764和程序P2 - 0249）。这个视频代表的“电穿孔技术为基础的技术和处理”的科学研讨会，并在斯洛文尼亚的卢布尔雅那大学电气工程学院举办的研究生课程，补充材料。

一，载入的细胞与细胞的跟踪CMFDA和CMRA <ol><li>实验在先前准备的细胞的小鼠黑色素瘤细胞株（B16 - F1）。细胞是生长在两个分开25厘米2培养瓶（TPP，ZDA）70-80％汇合（贝科改良Eagle培养基）DMEM培养液中，辅以10％胎牛血清，0.15 mg / ml的L -谷氨酰胺，16毫克/ ml的庆大霉素（Sigma - Aldrich公司，德国的所有），200单位/毫升crystacillin（Pliva公司，克罗地亚），并在5％的CO 2在37 ° C 。 </li><li>准备加入10.76μl和9μLDMSO（Sigma - Aldrich公司，德国）（分别为绿色CMFDA和橙色CMRA）50微克的染料在原有两个细胞纤夫10毫米股票的解决方案（Invitrogen公司，美国） Invitrogen公司的小瓶。原液可存放在冰箱在4 ° C几个月。在开始实验之前，热身的解决方案，直到二甲基亚砜晶体溶解。 </li><li>准备碳酸氢克雷布斯HEPES缓冲液（130毫米氯化钠，氯化钾4.7毫米，1.2毫米硫酸镁4，1.2毫米KH 2 PO 4，11.7毫米D -葡萄糖，氯化钙2 1.3毫米，10毫米的HEPES，pH值7.4）。 15 ml Eppendorf管中分别在两个混合每个原液2.1μL（10毫米CMFDA或CMRA），分别在碳酸氢克雷布斯HEPES缓冲液3毫升。这就产生了一个“加载的解决方案”，含有约7μMCMFDA（CMRA）。 </li><li>碳酸氢克雷布斯HEPES缓冲液冲洗细胞两次，然后插入装入烧瓶的解决方案。在5％的CO 2孵育30分钟的细胞在37 ° C 。在这第一次的孵化试剂自由穿过细胞膜，但一旦进入细胞内，所用试剂均为转化为细胞impermeant荧光反应产物。 </li><li>第一潜伏期后，冲洗和孵化与另外两个小时的细胞培养液中，在5％的CO 2在37 ° C。 </li><li> Trypsinize两个烧瓶中的细胞（CMFDA和CMRA加载）和混合红色和绿色的细胞在50 mL离心管中的比例为1:1（TPP，ZDA）。调整细胞浓度5 × 10 6细胞/毫升DMEM培养基稀释或浓度与离心机。将一个细胞悬液20μL每孔24多孔板（TPP，ZDA）下降。 5％的CO 2孵育细胞在37 ° C时20分钟，让他们稍微井表面的重视，并建立细胞接触。 </li></ol>二。电熔<ol><li>准备isoosomolar钾磷酸盐缓冲液（磷酸二氢钾10毫米，10毫米K 2 HPO 4，1MM氯化镁2，250毫米蔗糖）和hypoosmolar钾磷酸盐缓冲液（磷酸二氢钾10毫米，10毫米K 2 HPO 4，1MM MgCl 2的 ，75毫米蔗糖） 。 </li><li>到细胞在显微镜阶段，位置在井底部的电极放置多孔和它们连接到脉冲发生器。 </li><li> 1毫升的isoosomolar磷酸钾缓冲液洗细胞。新增350 hypoosmolar钾磷酸盐缓冲液，以诱导细胞肿胀。缓冲区应覆盖的电极。 </li><li>留在细胞应用电脉冲前2分钟hypoosmolar缓冲。在此期间的水分子进入细胞，由于细胞内部和外部之间的渗透压不平衡的时间涌入导致细胞体积增大。电脉冲应适用于当细胞接近其最大卷，监管量减少启动前。 </li><li> ，为了达到最佳的电熔，并保持细胞活力，应使用最佳参数的电脉冲。这取决于使用[1]的细胞株。 8矩形脉冲（每100μs的时间在1 Hz）的列车在这个实验中是适用于每个样本，使用电设备（我们的情况下Cliniporator，Igea酒店，意大利）。该脉冲传递到两条平行的Pt / Ir电极丝与它们之间的0.8毫米直径5毫米的距离，创造约1200 V /厘米，每孔的电极之间的电场，除了控制好。 </li><li>保留10分钟后，脉冲传递不受干扰细胞。确定的荧光灯和相衬显微镜融合产量。 </li></ol>三。图像采集和融合产量测定<ol><li> （在我们的例子中，德国蔡司ZEISS AXIOVERT 200）配有一个客观的（X20）和一个冷却CCD相机（VisiCam 1280 Visitron，德国）荧光显微镜观察细胞。图像采集MetaMorph 7.1.1分子器件，（美国），但也可用于其他类似的数据采集软件。在548 nm处，在492 nm处的单色（多彩四，Visitron，德国）和CMRA CMFDA是兴奋。 CMFDA和CMRA荧光收购使用两个排放过滤器，一个为535 nm为中心（HQ535/30m，CMFDA）和其他中心在510 nm（D605/55m，为CMRA的，无论是色度，美国）。分色镜（Q515LP）的使用，阻碍了通道串扰。 </li><li>每口井的5个随机选择的领域获得三幅图像（相衬，红色和绿色荧光）。创建每个图像三重的三个通道的图像。在这样的图像可以看出荧光细胞质与细胞膜一起。融合细胞，因此可以很容易地确定[图1]。 </li><li>所有三种类型的细胞（红色，绿色和双重荧光）计数在每三个通道的图像。确定每幅图像中的所有细胞数量的双重荧光的细胞数量除以的双重荧光细胞的百分比。融合率被定义为百分比乘以2的双重荧光细胞，因为融合细胞的一半都没有检测到（当相同颜色的保险丝细胞）。 </li></ol>代表性的成果<img src="/files/ftp_upload/1991/1991fig1.jpg" alt="图1" /> 图1三通道B16F1细胞电融合后的显微镜图像 。相衬，CMRA荧光（在548 nm的激发）和CMFDA荧光（492 nm处的激发） ，物镜20X

<ol>
	<li>&#268;emazar, M., Jarm, T., Miklav&#269;i&#269;, D., Ma&#269;ek-Lebar, A., Ihan, A., Kopitar, N. A., Ser&#353;a, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+electric-field+intensity+on+electropermeabilization+and+electrosensitivity+of+various+tumor-cell+lines+in+vitro.">Effect of electric-field intensity on electropermeabilization and electrosensitivity of various tumor-cell lines in vitro.</a> Electro. Magnetobiol. 17, 263-272 (1998).</li><li>Trontelj, K., Reber&#353;ek, M., Kandu&#353;er, M., &#269;urin &#353;erbec, V., Miklav&#269;i&#269;, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+bulk+cell+electrofusion+in+vitro+for+production+of+human-mouse+heterohybridoma+cells.">Optimization of bulk cell electrofusion in vitro for production of human-mouse heterohybridoma cells.</a> Bioelectrochemistry. 74, 124-129 (2008).</li><li>Rols, M. -. P., Teissi&#233;, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modulation+of+electrically+induced+permeabilization+and+fusion+of+Chinese+hamster+ovary+cells+by+osmotic+pressure.">Modulation of electrically induced permeabilization and fusion of Chinese hamster ovary cells by osmotic pressure.</a> Biochemistry. 29, 4561-4567 (1990).</li><li>Neil, G., Zimmermann, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrofusion.">Electrofusion.</a> Methods in Enzymology. 220, 174-196 .</li><li>Abidor, I. G., Li, L. -. H., Hui, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+of+cell+pellets:+II.+Osmotic+properties,+electroporation,+and+related+phenomena:+Membrane+interactions.">Studies of cell pellets: II. Osmotic properties, electroporation, and related phenomena: Membrane interactions.</a> Biophysical journal. 67, 427-435 (1994).</li><li>Jaroszeski, M. J., Gilbert, R., Fallon, P. G., Heller, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanically+facilitated+cell-cell+electrofusion.">Mechanically facilitated cell-cell electrofusion.</a> Biophys J. 67 (4), 1574-1581 (1994).</li><li>Ramos, C., Bonefant, D., Teissi&#233;, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+hybridization+by+electrofusion+on+filters.">Cell hybridization by electrofusion on filters.</a> Analytical biochemistry. 302, 213-219 (2002).</li><li>Cao, Y., Yang, J., Yin, Z. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+of+high-throughput+cell+electrofusion+in+a+microelectrode-array+chip.">Study of high-throughput cell electrofusion in a microelectrode-array chip.</a> Microfluid Nanofluid. 5, 669-675 (2008).</li><li>U&#353;aj, M., Trontelj, M., Kandu&#353;er, M., Miklav&#269;i&#269;, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+size+dynamics+and+viability+of+cells+exposed+to+hypotonic+treatment+and+electroporation+for+electrofusion+optimization.">Cell size dynamics and viability of cells exposed to hypotonic treatment and electroporation for electrofusion optimization.</a> Radiol. Oncol. 43, 108-119 (2009).</li><li>Teissi&#233;, J., Ramos, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+between+electric+field+pulse+induced+long-lived+permeabilization+and+fusogenicity+in+cell+membranes.">Correlation between electric field pulse induced long-lived permeabilization and fusogenicity in cell membranes.</a> Biophys. J. 74, 1889-1898 (1998).</li></ol>

非特异性，如外部电场，细胞膜的融合能力是非​​常重要的生物技术，医学和生物学研究。这种非特异性的融合，使非常宝贵的杂交细胞和他们的产品，如单克隆抗体，的生产，并提供信息融合[2]的基本机制。电熔是一个潜在的非常有效的方法，因为它可以适当调整不同类型的细胞。电熔时细胞在亲密的身​​体接触到他们fusogenic的国家带来的（容易融合）通过高压电脉冲。电熔效率取决于影响的电熔过程中的两个部分的各种参数。电熔过程中的第一部分，是实现细胞之间的密切的身体接触，可以用不同的方法获得的[3-8]。坚持的方法（生长期的细胞汇合），可以有效地使用，由于在自发设立的大区之间的细胞的细胞接触，但是，它会产生非常大，许多核细胞融合。我们使用的是修改后的坚持方法，较小的细胞（2至5原子核），这是更容易存活和增殖，获得（图1）。细胞之间的联系也有利于从细胞的渗透压肿胀，由于渗透压的治疗实验[9]中使用。电熔过程中的第二部分，是实现fusogenic状态的细胞膜。 Fusogenic国家相互关系以及与electropermeabilized膜状态的细胞都是非，特别通透，通常可以不通过通过完整的膜的分子和的电脉冲（振幅，长度，数量和频率）的相同参数管[10] 。最佳电所需的电气参数值[1]和电熔差异不同的细胞，取决于细胞的大小和其生物学特性。电气参数，因此需要不同的细胞系，这是用来作为融合伙伴，获得融合优化。

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>CMRA</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>C34551</td>
<td>Cytosolic fluorescent dye</td>
</tr>
<tr>
<td>CMFDA</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>C7025</td>
<td>Cytosolic fluorescent dye</td>
</tr>
<tr>
<td>DMSO</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>D2650</td>
<td>&nbsp;</td>
<tr>
<td>DMEM </td>
<td>Reagent</td>
<td>Sigma-Aldrich </td>
<td>D5671</td>
<td>Dulbecco's modified Eagle's medium</td>
</tr>
<tr>
<td>Fetal calf serum</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>F4135</td>
<td>&nbsp;</td>
<tr>
<td>L-glutamine</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>G7513</td>
<td>&nbsp;</td>
<tr>
<td>crystacillin</td>
<td>Reagent</td>
<td>Pliva</td>
<td>625110</td>
<td>antibiotic</td>
</tr>
<tr>
<td>gentamicin</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>G1397</td>
<td>antibiotic</td>
</tr>
<tr>
<td>Hepes</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>H0887</td>
<td>&nbsp;</td>
<tr>
<td>KH2PO4</td>
<td>Reagent</td>
<td>Merck </td>
<td>A124873 927</td>
<td>&nbsp;</td>
<tr>
<td>KH2PO4</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>4248</td>
<td>&nbsp;</td>
<tr>
<td>MgCl2</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>M-8266</td>
<td>&nbsp;</td>
<tr>
<td>NaCl</td>
<td>Reagent</td>
<td>Fluka</td>
<td>71382</td>
<td>&nbsp;</td>
<tr>
<td>KCl</td>
<td>Reagent</td>
<td>Merck</td>
<td>A154336 908</td>
<td>&nbsp;</td>
<tr>
<td>MgSO4</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>M2643</td>
<td>&nbsp;</td>
<tr>
<td>D-glucose</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>G8270</td>
<td>&nbsp;</td>
<tr>
<td>CaCl2</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>C4901</td>
<td>&nbsp;</td>
<tr>
<td>sucrose</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>16104</td>
<td>&nbsp;</td>
<tr>
<td>Electric pulse generator</td>
<td>Tool</td>
<td>Igea</td>
<td>&nbsp;</td>
<td>Cliniporator VITAE</td>
</tr>
<tr>
<td>Multiwell plate</td>
<td>Tool</td>
<td>TPP</td>
<td>92424</td>
<td>&nbsp;</td>
<tr>
<td>50 ml centrifuge tube</td>
<td>Tool</td>
<td>TPP</td>
<td>91050</td>
<td>&nbsp;</td>
<tr>
<td>15 ml centrifuge tube</td>
<td>Tool</td>
<td>TPP</td>
<td>91015</td>
<td>&nbsp;</td>
<tr>
<td>25 cm2 culture flask</td>
<td>Tool</td>
<td>TPP</td>
<td>90026</td>
<td>&nbsp;</td>
<tr>
<td>Electrodes</td>
<td>Tool</td>
<td>Custom made</td>
<td>&nbsp;</td>
<td>Pt/Ir</td>
</tr>		</tbody>
		</table>
		</div>

cell electrofusion visualized with fluorescence microscopy

细胞电融合是一种安全，非病毒性和非化学的方法，准备为人类治疗的杂交细胞，可用于使用。电熔涉及短期高电压密切联系的细胞的电脉冲的应用。总之，高电压的电脉冲的应用会导致不稳定的细胞质膜。不稳定的膜是不同的分子和通透性增加，也容易与任何邻国的不稳定，膜融合。电熔是一个方便的方法来实现一个非常不同的细胞非特异性融合<em&gt;在体外</em&gt;。为了获得融合，细胞膜，由电场不稳定，必须在一次亲密接触，让他们的脂质双层合并，因此细胞质。在这段视频中，我们展示了高效的细胞电融合<em&gt;在体外</em&gt;改性坚持方法手段。在此方法中，细胞被允许连接井表面只有轻微的，因此，媒体可以进行交换，细胞仍然保留他们的球形。融合的可视化是评估前的标签具有不同的荧光细胞跟踪染料的细胞的细胞质中，一半的细胞标记，橙色CMRA和绿色CMFDA另一半。融合产量双重荧光的细胞数除以乘以2的所有细胞的数量决定。

Watch this Scientific Journal Video about Cell Electrofusion Visualized with Fluorescence Microscopy at JoVE.com

Cell Electrofusion Visualized with Fluorescence Microscopy

在这个视频中，我们表现出高效的细胞电融合<em&gt;在体外</em&gt;修改坚持使用电和随后的细胞融合与可视化荧光显微镜检测方法。

荧光显微镜下细胞电融合的可视化

Cell electrofusion is a safe, non-viral and non-chemical method that can be used for preparing hybrid cells for human therapy. Electrofusion involves ...

cell-electrofusion-visualized-with-fluorescence-microscopy

Research

JoVE Journal

Biology

14.0K 次观看.  University of Ljubljana. 在这个视频中，我们表现出高效的细胞电融合在体外修改坚持使用电和随后的细胞融合与可视化荧光显微镜检测方法。

视频: Cell Electrofusion Visualized with Fluorescence Microscopy

Visualizing Single-molecule DNA Replication with Fluorescence Microscopy

We describe a simple fluorescence microscopy-based real-time method for observing DNA replication at the single-molecule level. A circular, forked DNA template is attached to a functionalized glass coverslip and replicated extensively after introduction of replication proteins and nucleotides (Figure 1). The growing product double-strand DNA (dsDNA) is extended with laminar flow and visualized by using an intercalating dye. Measuring the position of the growing DNA end in real time allows precise determination of replication rate (Figure 2). Furthermore, the length of completed DNA products reports on the processivity of replication. This experiment can be performed very easily and rapidly and requires only a fluorescence microscope with a reasonably sensitive camera.


This protocol demonstrates a simple single-molecule fluorescence microscopy technique for visualizing DNA replication by individual replisomes in real time.

可视化的单分子荧光显微镜下的DNA复制

We describe a simple fluorescence microscopy-based real-time method for observing DNA replication at the single-molecule level. A circular, forked DNA ...

科研

生物学

Dopamine Release at Individual Presynaptic Terminals Visualized with FFNs

The nervous system transmits signals between neurons via neurotransmitter release during synaptic vesicle fusion. To observe neurotransmitter uptake and release from individual presynaptic terminals directly, we designed fluorescent false neurotransmitters as substrates for the synaptic vesicle monoamine transporter. Using these probes to image dopamine release in the striatum, we made several observations pertinent to synaptic plasticity. We found that the fraction of synaptic vesicles releasing neurotransmitter per stimulus was dependent on the stimulus frequency. A kinetically distinct "reserve" synaptic vesicle population was not observed under these experimental conditions. A frequency-dependent heterogeneity of presynaptic terminals was revealed that was dependent in part on D2 dopamine receptors, indicating a mechanism for frequency-dependent coding of presynaptic selection.

Hui Zhang and Niko G. Gubernator contributed equally to this work.

A new means to measure neurotransmission optically using fluorescent dopamine analogs.

多巴胺的释放突触前货箱码头在个别的可视化与FFNs

The nervous system transmits signals between neurons via neurotransmitter release during synaptic vesicle fusion. To observe neurotransmitter uptake and ...

Time-lapse Imaging of Mitosis After siRNA Transfection

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and cellular content. Hallmark events of mitosis, such as chromosome movement, can be readily tracked on an individual cell basis using time-lapse fluorescence microscopy of mammalian cell lines expressing specific GFP-tagged proteins. In combination with RNAi-based depletion, this can be a powerful method for pinpointing the stage(s) of mitosis where defects occur after levels of a particular protein have been lowered. In this protocol, we present a basic method for assessing the effect of depleting a potential mitotic regulatory protein on the timing of mitosis. Cells are transfected with siRNA, placed in a stage-top incubation chamber, and imaged using an automated fluorescence microscope. We describe how to use software to set up a time-lapse experiment, how to process the image sequences to make either still-image montages or movies, and how to quantify and analyze the timing of mitotic stages using a cell-line expressing mCherry-tagged histone H2B. Finally, we discuss important considerations for designing a time-lapse experiment. This strategy is complementary to other approaches and offers the advantages of 1) sensitivity to changes in kinetics that might not be observed when looking at cells as a population and 2) analysis of mitosis without the need to synchronize the cell cycle using drug treatments. The visual information from such imaging experiments not only allows the sub-stages of mitosis to be assessed, but can also provide unexpected insight that would not be apparent from cell cycle analysis by FACS.

Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection.

有丝分裂的siRNA转染后的时间推移成像

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and ...

Quantitative Live Cell Fluorescence-microscopy Analysis of Fission Yeast

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using fluorochromes like Green Fluorescent Protein (GFP) directly attached to the protein of interest has become increasingly popular 1. Using GFP and similar fluorochromes the subcellular localisations and movements of proteins can be detected in a fluorescent microscope. Moreover, also the subnuclear localisation of a certain region of a chromosome can be studied using this technique. GFP is fused to the Lac Repressor protein (LacR) and ectopically expressed in the cell where tandem repeats of the lacO sequence has been inserted into the region of interest on the chromosome2. The LacR-GFP will bind to the lacO repeats and that area of the genome will be visible as a green dot in the fluorescence microscope. Yeast is especially suited for this type of manipulation since homologous recombination is very efficient and thereby enables targeted integration of the lacO repeats and engineered fusion proteins with GFP 3. Here we describe a quantitative method for live cell analysis of fission yeast. Additional protocols for live cell analysis of fission yeast can be found, for example on how to make a movie of the meiotic chromosomal behaviour 4. In this particular experiment we focus on subnuclear organisation and how it is affected during gene induction. We have labelled a gene cluster, named Chr1, by the introduction of lacO binding sites in the vicinity of the genes. The gene cluster is enriched for genes that are induced early during nitrogen starvation of fission yeast 5. In the strain the nuclear membrane (NM) is labelled by the attachment of mCherry to the NM protein Cut11 giving rise to a red fluorescent signal. The Spindle Pole body (SPB) compound Sid4 is fused to Red Fluorescent Protein (Sid4-mRFP) 6. In vegetatively growing yeast cells the centromeres are always attached to the SPB that is embedded in the NM 7. The SPB is identified as a large round structure in the NM. By imaging before and 20 minutes after depletion of the nitrogen source we can determine the distance between the gene cluster (GFP) and the NM/SPB. The mean or median distances before and after nitrogen depletion are compared and we can thus quantify whether or not there is a shift in subcellular localisation of the gene cluster after nitrogen depletion.

The fission yeast, Schizosaccharomyces pombe, is a good model system to study basic cellular processes. Here we describe a method to perform quantitative live cell analysis of fission yeast. In this particular experiment we focus on organisation of the genome within the cell nucleus, but the method can also be used to study cytosolic factors.

裂殖酵母的活细胞定量荧光显微镜分析

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using ...

Simultaneous Multicolor Imaging of Biological Structures with Fluorescence Photoactivation Localization Microscopy

Localization-based super resolution microscopy can be applied to obtain a spatial map (image) of the distribution of individual fluorescently labeled single molecules within a sample with a spatial resolution of tens of nanometers. Using either photoactivatable (PAFP) or&#160;photoswitchable (PSFP) fluorescent proteins fused to proteins of interest, or organic dyes conjugated to antibodies or other molecules of interest, fluorescence photoactivation localization microscopy (FPALM) can simultaneously image multiple species of molecules within single cells. By using the following approach, populations of large numbers (thousands to hundreds of thousands) of individual molecules are imaged in single cells and localized with a precision of ~10-30 nm. Data obtained can be applied to understanding the nanoscale spatial distributions of multiple protein types within a cell. One primary advantage of this technique is the dramatic increase in spatial resolution: while diffraction limits resolution to ~200-250 nm in conventional light microscopy, FPALM can image length scales more than an order of magnitude smaller. As many biological hypotheses concern the spatial relationships among different biomolecules, the improved resolution of FPALM can provide insight into questions of cellular organization which have previously been inaccessible to conventional fluorescence microscopy. In addition to detailing the methods for sample preparation and data acquisition, we here describe the optical setup for FPALM. One additional consideration for researchers wishing to do super-resolution microscopy is cost: in-house setups are significantly cheaper than most commercially available imaging machines. Limitations of this technique include the need for optimizing the labeling of molecules of interest within cell samples, and the need for post-processing software to visualize results. We here describe the use of PAFP and PSFP expression to image two protein species in fixed cells. Extension of the technique to living cells is also described.

We demonstrate the use of fluorescence photo activation localization microscopy (FPALM) to simultaneously image multiple types of fluorescently labeled molecules&#160;within cells. The techniques described yield the localization of thousands to hundreds of thousands of individual fluorescent labeled proteins, with a precision of tens of nanometers&#160;within single cells.

Localization-based super resolution microscopy can be applied to obtain a spatial map (image) of the distribution of individual fluorescently labeled ...

Protein-protein Interactions Visualized by Bimolecular Fluorescence Complementation in Tobacco Protoplasts and Leaves

Many proteins interact transiently with other proteins or are integrated into multi-protein complexes to perform their biological function. Bimolecular fluorescence complementation (BiFC) is an in vivo method to monitor such interactions in plant cells. In the presented protocol the investigated candidate proteins are fused to complementary halves of fluorescent proteins and the respective constructs are introduced into plant cells via agrobacterium-mediated transformation. Subsequently, the proteins are transiently expressed in tobacco leaves and the restored fluorescent signals can be detected with a confocal laser scanning microscope in the intact cells. This allows not only visualization of the interaction itself, but also the subcellular localization of the protein complexes can be determined. For this purpose, marker genes containing a fluorescent tag can be coexpressed along with the BiFC constructs, thus visualizing cellular structures such as the endoplasmic reticulum, mitochondria, the Golgi apparatus or the plasma membrane. The fluorescent signal can be monitored either directly in epidermal leaf cells or in single protoplasts, which can be easily isolated from the transformed tobacco leaves. BiFC is ideally suited to study protein-protein interactions in their natural surroundings within the living cell. However, it has to be considered that the expression has to be driven by strong promoters and that the interaction partners are modified due to fusion of the relatively large fluorescence tags, which might interfere with the interaction mechanism. Nevertheless, BiFC is an excellent complementary approach to other commonly applied methods investigating protein-protein interactions, such as coimmunoprecipitation, in vitro pull-down assays or yeast-two-hybrid experiments.

Formation of protein complexes in vivo can be visualized by bimolecular fluorescence complementation. Interaction partners are fused to complementary parts of fluorescent tags and transiently expressed in tobacco leaves, resulting in a reconstituted fluorescent signal upon close proximity of the two proteins.

蛋白质 - 蛋白质相互作用的双分子荧光互补的烟草原生质体和叶片可视化

Many proteins interact transiently with other proteins or are integrated into multi-protein complexes to perform their biological function. Bimolecular ...

Sample Preparation for Single Virion Atomic Force Microscopy and Super-resolution Fluorescence Imaging

Immobilization of virions to glass surfaces is a critical step in single virion imaging. Here we present a technique&#160;adopted from single molecule imaging assays which allows adhesion of single virions to glass surfaces with specificity. This preparation is based on grafting the surface of the glass with a mixture of PLL-g-PEG and PLL-g-PEG-Biotin, adding a layer of avidin, and finally creating virion anchors through attachment of biotinylated virus specific antibodies. We have applied this technique across a range of experiments including atomic force microscopy (AFM) and super-resolution fluorescence imaging. This sample preparation method results in a control adhesion of the virions to the surface.

The attachment of virions to a surface is a requirement for single virion imaging by Super-resolution fluorescence imaging or atomic force microscopy (AFM). Here we demonstrate a sample preparation method for controlled adhesion of virions to glass surfaces suitable for use in AFM and super-resolution fluorescence imaging.

单病毒原子力显微镜和超分辨率荧光成像的样品制备

Immobilization of virions to glass surfaces is a critical step in single virion imaging. Here we present a technique&#160;adopted from single molecule ...

Visualizing Stromule Frequency with Fluorescence Microscopy

Stromules, or "stroma-filled tubules", are narrow, tubular extensions from the surface of the chloroplast that are universally observed in plant cells but whose functions remain mysterious. Alongside growing attention on the role of chloroplasts in coordinating plant responses to stress, interest in stromules and their relationship to chloroplast signaling dynamics has increased in recent years, aided by advances in fluorescence microscopy and protein fluorophores that allow for rapid, accurate visualization of stromule dynamics. Here, we provide detailed protocols to assay stromule frequency in the epidermal chloroplasts of Nicotiana benthamiana, an excellent model system for investigating chloroplast stromule biology. We also provide methods for visualizing chloroplast stromules in vitro by extracting chloroplasts from leaves. Finally, we outline sampling strategies and statistical approaches to analyze differences in stromule frequencies in response to stimuli, such as environmental stress, chemical treatments, or gene silencing. Researchers can use these protocols as a starting point to develop new methods for innovative experiments to explore how and why chloroplasts make stromules.

Protocols to investigate the dynamics of chloroplast stromules, the stroma-filled tubules that extend from the surface of chloroplasts, are described.

可视化Stromule频率与荧光显微镜

Stromules, or "stroma-filled tubules", are narrow, tubular extensions from the surface of the chloroplast that are universally observed in plant cells but ...

Light Sheet Fluorescence Microscopy of Plant Roots Growing on the Surface of a Gel

One of the key questions in understanding plant development is how single cells behave in a larger context of the tissue. Therefore, it requires the observation of the whole organ with a high spatial- as well as temporal resolution over prolonged periods of time, which may cause photo-toxic effects. This protocol shows a plant sample preparation method for light-sheet microscopy, which is characterized by mounting the plant vertically on the surface of a gel. The plant is mounted in such a way that the roots are submerged in a liquid medium while the leaves remain in the air. In order to ensure photosynthetic activity of the plant, a custom-made lighting system illuminates the leaves. To keep the roots in darkness the water surface is covered with sheets of black plastic foil. This method allows long-term imaging of plant organ development in standardized conditions.

This protocol shows a plant sample preparation method for light-sheet microscopy. The setup is characterized by mounting the plant vertically on the surface of a gel and letting it grow in controlled bright conditions. This allows long-term observation of plant organ development in standardized conditions.

植物根系的轻质板材荧光显微镜生长在一个凝胶表面

One of the key questions in understanding plant development is how single cells behave in a larger context of the tissue. Therefore, it requires the ...

Open-source Single-particle Analysis for Super-resolution Microscopy with VirusMapper

Super-resolution fluorescence microscopy is currently revolutionizing cell biology research. Its capacity to break the resolution limit of around 300 nm allows for the routine imaging of nanoscale biological complexes and processes. This increase in resolution also means that methods popular in electron microscopy, such as single-particle analysis, can readily be applied to super-resolution fluorescence microscopy. By combining this analytical approach with super-resolution optical imaging, it becomes possible to take advantage of the molecule-specific labeling capacity of fluorescence microscopy to generate structural maps of molecular elements within a metastable structure. To this end, we have developed a novel algorithm &#8212; VirusMapper &#8212; packaged as an easy-to-use, high-performance, and high-throughput ImageJ plugin. This article presents an in-depth guide to this software, showcasing its ability to uncover novel structural features in biological molecular complexes. Here, we present how to assemble compatible data and provide a step-by-step protocol on how to use this algorithm to apply single-particle analysis to super-resolution images.

This manuscript uses the Fiji-based open-source software package VirusMapper to apply single-particle analysis to super-resolution microscopy images in order to generate precise models of nanoscale structure.

与VirusMapper超分辨率显微镜开源单粒子分析

Super-resolution fluorescence microscopy is currently revolutionizing cell biology research. Its capacity to break the resolution limit of around 300 nm ...