我们要感谢支持沿海和公海水域低氧气地区正在进行的研究创新，不列颠哥伦比亚省知识发展基金和国家科学和工程研究理事会（NSERC），加拿大的加拿大基金会。 JJW是由NSERC和DAW奖学金的支持是由NSERC，Killam和图拉基金会资助的微生物多样性和进化中心奖学金的支持。 SL是由微生物多样性和进化图拉基金会资助中心的支持。

注：在本议定书中所使用的所有试剂是从实验室股票分装成较小的工作库存，这是非常重要的，以避免交叉污染你的DNA样本和实验室股市污染。 此外，移液时，一定要改变每此外，避免交叉污染移液器。 第一部分：细胞裂解和消化<ol><li>开始融化的冰包含以前集中的浮游生物质Sterivex过滤器本议定书。为了简单起见，这里我们描述的程序，用于处理个人过滤器。在实践中，我们建议在同一时间处理16个或更少的过滤器。 </li><li>一旦过滤器已解冻，首先开始的两个孵化：裂解细胞，除去RNA，并之一分解蛋白质。对于第一个孵化，添加100μL溶菌酶（1000μLTE 125毫克）和20毫升RNA酶A（10微克/毫升）的过滤器。重新密封封口膜过滤和离开旋转在37℃，1小时杂交炉。 </li><li>对于未来的孵化，添加100μL蛋白酶K和100μL20％SDS的过滤器。重新封装用封口膜，让它在杂交炉旋转一到两个小时以上，这一次在55 ° C </li><li>使用5CC针筒，从Sterivex过滤器转移到一个15毫升猎鹰管的裂解。用1 ml裂解液冲洗过滤器，并添加在您的猎鹰管裂解液使用5CC注射器冲洗液体。现在，你有你的细胞溶解和消化，你就可以提取他们的DNA。 </li></ol>第二部分：DNA的提取<ol><li>下一步是用酚 - 氯仿法提取DNA裂解。加入等体积的苯酚（约3毫升）：氯仿：异戊醇（IAA），裂解管，一定要改变每个此外枪头，避免交叉污染。涡为10秒拌匀。 </li><li>在2500克5分钟的旋转管，确保离心机平衡。在离心，酚 - 氯仿裂解液混合应分成两层：您的样品含有苯酚，氯仿和蛋白质在底部的有机层，水层，包括你的DNA，水，和其他更多的亲水性分子，在最前面。 </li><li>转移到一个新的15毫升猎鹰管的水层（含你的DNA）。要小心不要碰到枪头（总是留下少量背后的水层）的接口。 </li><li>这一新的试管中，加等体积的氯仿（约3ML）：生长素，一定要改变每个此外枪头，避免交叉污染。涡为10秒。此步骤有助于从你的DNA样本中删除任何剩余的苯酚。 </li><li> 2500克分拆为5分钟，或直至水层是明确的。转移到一个新的标记猎鹰管水层，并在pH 8.0中添加1毫升的TE，小心不要碰到枪头（总是留下少量背后的水层）的接口。这个水层包含您的DNA提取。 </li></ol>第三部分：DNA浓度和洗涤<ol><li>下一步是清洗和集中在15毫升Amicon超离心管的DNA样本。 Amicon管组成一个过滤器，保留或以上指定的分子量截留和管分子赶上流（滤液）。在这种情况下，过滤掉你的DN​​A（截留）。您的DNA提取步骤2.5传输Amicon超管过滤器舱。 </li><li> 10分钟旋转3500克。检查，以确保有少于1毫升液体保留在Amicon过滤器。如果再次更截留的遗体，笔芯用TE的过滤器和旋转。确保使用每TE另外一个新的枪头，避免交叉污染。 </li><li>取出流过，或滤液，到另一个猎鹰管，在冰箱中保存，直到您确认您的最终DNA凝胶产品（第四部分）。 </li><li>加入2 ml TE缓冲液中的Amicon过滤器和旋转3500克为6分钟，确保每个TE除了使用一个新的枪头，避免交叉污染。游泳池与步骤3.3滤液，保存在冰箱中。 </li><li>洗净的三个清洗（一定要始终使用一个新的枪头）的总DNA用TE两倍以上，并保存每次滤液（如3.3和3.4％的步骤）。最后一次洗涤，旋转，直到200至500毫升Amicon过滤截留仍然。记录最终体积和转移截留（含你的DNA）一个标记的1.5 mL Eppendorf管。 </li></ol>第四部分：DNA质量的测定<ol><li>检查的DNA质量和浓度的DNA凝胶0.8％琼脂糖凝胶STA运行您的样品估计独立非执行董事与1毫升溴化乙锭（ETBR）过夜。 （极为谨慎，在使用ETBR时，它是已知的诱变剂和可疑致癌物质。确保经常更换手套，并避免ETBR转移到了实验室的休息和你的皮肤。）装入样品的DNA梯子旁边，作为规模和强度标准（见下一步）。 </li><li>在第几车道，装入不同的分子量和浓度的乐队的梯子。我们建议以下加载模式：在第一个和最后一个车道（最外面的车道），负载10μL50ng/μl的1KB +或2log阶梯。在2,3和4车道，负载2μL，5μL，10μL，分别50ng/μlλHindIII梯，。最后，负载5％的DNA与染料的提取，每个样品巷液。 </li><li>运行约16小时15伏（我们建议运行过夜）凝胶。 </li><li>第二天，照片使用紫外凝胶成像系统凝胶。要确定你的DNA，其浓度的分子量范围，比较样品带梯子的乐队。质量好的DNA分子量高（&gt; 36KB），而且几乎没有证据显示剪切/退化。见图1。 </li></ol>第五部分：氯化铯梯度离心<ol><li>如果DNA质量好，数量足够的，可以继续执行氯化铯（CSCL）梯度离心纯化的DNA。请注意，这一步纯化是可选的，并不需要所有下游应用（例如，如果你要生成fosmid库，你应该净化，而 ​​如果你只是想进行PCR反应，净化通常没有必要）。首先，一个标签，每个样品的离心管中。 </li><li>每个离心管中，添加160毫克，178μL的基因组DNA中海集运。 CSCL和DNA管后，将封口膜管上的一个小块，轻轻颠倒管10到20倍，以组合的组成部分。不要混用吹打，这可能会导致DNA的剪切。接下来，添加10μL10μg/μL的ETBR此管，并以同样的方式混合。 （使用时极为谨慎ETBR，它是一种已知的诱变剂的和可疑致癌物质，确保经常更换手套，并避免ETBR转移到了实验室的休息和你的皮肤。） </li><li>确保所有管的重量是平衡前离心管之间的重量差异小于1毫克。 </li><li>放置在转子使用止血钳管，盖上盖子，放在超速离心机内转子。 </li><li>关闭超速离心机门。真空，将尽快关门。运行过夜100000 RPM为18小时和20 ° C </li><li>离心完成后，取出从一个试管架使用止血钳和地点转子管。 </li><li>可视化与蓝色光透射的DNA，如果不可用，使用长波长的紫外线灯，在黑暗的房间里。穿一双琥珀色的过滤器眼镜，看到的DNA带。参见图2。 </li><li>使用1CC一​​个无菌注射器和针头（26G 5 / 8），删除DNA条带，并放置在1.5毫升Eppendorf管。 </li><li>为了帮助恢复，大部分被困在注射器中的死亡空间的DNA，与100μLTE冲洗注射器和清洗解决方案添加到管。 100μLTE缓冲每个样品准备一管，以防止交叉污染。 </li><li>要删除的DNA ETBR，加等体积的水饱和正丁醇管，反转管轻轻10到20倍，在1分钟的转速10000离心机和丢弃的顶层。 </li><li>重复清洗，直至丁醇的颜色是透明的，3 - 4次以上。 </li><li>在Amicon超离心管置于4毫升TE和添加从上面的DNA溶液。 </li><li>离心机在室温下在3500克，直到DNA量减少约100-500μL（约6-7分钟），并丢弃流过。 </li><li>加入2ml TE Amicon过滤器和离心机3500克为6分钟，一定要使用每次添加一个新的枪头，避免交叉污染。重复两次。 </li><li>集中到一个最终体积50-100微升，必要时可额外离心和DNA溶液过滤器转移到一个新的1.5 mL Eppendorf管。 </li><li>加入40μLTE Amicon过滤器和吸管两侧滤膜向上和向下洗出任何剩余的DNA。加入这个解决方案在5.15管。 </li><li>加入200μL灭菌水，并在7分钟10000转离心，放入一个单片机管和预洗的单片机的一个单片机YM - 30过滤装置。 </li><li> DNA溶液中加入5.16预洗单片机为了进一步集中的DNA。在5000-10000克为1 - 3分钟离心。检查的液体量离心过滤器和重复，直到液体过滤器上的金额减少约50μL。 </li><li>过滤装置，倒挂在一个新的单片机管离心3分钟，并在1000克。理想的浓缩液量为50-60μL。 </li><li>测量和记录的DNA Nanodrop的浓度和峰值质量检查（应260nm）。 </li><li>一个小等份的DNA转移到一个干净的Eppendorf管工作在零下20的股票和冻结。其余的DNA转移到第二个干净的Eppendorf和冻结在零下80。 </li></ol>代表性的成果： 当这个协议是正确的，你应该看到后测定DNA的质量与图1类似的步骤4.4凝胶图像。实际提取DNA的浓度会有所不同取决于示例的源。在CsCl梯度离心5.7步后，蓝色的光芒照亮的基因组DNA应该类似于图2。 <img src="/files/ftp_upload/1352/1352Fig1newer.png" alt="图1" /> 图1。0.8％琼脂糖凝胶电泳图像的超高分子量从四个深度在亚北极太平洋（一式二份）与嵌入剂，溴化乙锭（10毫克/毫升）染色，收集DNA。凝胶1X TBE凝胶电泳缓冲液中，在15V〜16小时运行。样品带呈现出良好的机械剪切几乎没有证据显示反对多个频段的单波段或涂片质量虽然10米的提取物保留一些RNA进行（见涂抹在0.5至2.0 KB范围）。 <img src="/files/ftp_upload/1352/1352Fig2.jpg" alt="图2" /> 图2。基因组DNA带蓝色光照射后，CsCl梯度离心。

<ol>
	<li>Beja, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=To+BAC+or+not+to+BAC:+marine+ecogenomics.">To BAC or not to BAC: marine ecogenomics.</a> Curr Opin Biotechnol. 15 (3), 187-190 (2004).</li><li>Beja, O., Suzuki, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+and+analysis+of+bacterial+artificial+chromosome+libraries+from+a+marine+microbial+assemblage.">Construction and analysis of bacterial artificial chromosome libraries from a marine microbial assemblage.</a> Environ Microbiol. 2 (5), 516-529 (2000).</li><li>DeLong, E. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Community+genomics+among+stratified+microbial+assemblages+in+the+oceans+interior.">Community genomics among stratified microbial assemblages in the oceans interior.</a> Science. 311, 496-503 (2006).</li><li>Stein, J. L., Marsh, T. L. <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+uncultivated+prokaryotes:+isolation+and+analysis+of+a+40-kilobase-pair+genome+fragment+from+a+planktonic+marine+archaeon.">Characterization of uncultivated prokaryotes: isolation and analysis of a 40-kilobase-pair genome fragment from a planktonic marine archaeon.</a> J Bacteriol. 178 (3), 591-599 (1996).</li><li>Somerville, C. C., Knight, I. T., Straube, W. L., Colwell, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple,+rapid+method+for+the+direct+isolation+of+nucleic+acids+from+aquatic+environments.">A simple, rapid method for the direct isolation of nucleic acids from aquatic environments.</a> Appl. Environ. Microbiol. 55 (3), 548-554 (1989).</li></ol>

根据要处理多少样本，这可能是一个时间密集型的过程，由于两个小时的孵化步骤，和反复洗涤，离心步骤。这是最好的计划，此过程整整两天，留下充裕的时间。如果有问题Amicon管最终提取量减少了200 -500μL，在DNA的浓度和洗涤，尝试做更多的TE清洗和离心（重复第三部分），直到合适的音量是吃剩的。此外，如果敏锐的氯仿提取物的​​气味，这是最好做额外的清洗，直到气味减轻，以确保所...

A correction was made to "<a href="/video/1352">DNA Extraction from 0.22 &#181;M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation</a>". A typo in a volume's measurement was corrected in step 1.2.
The step was corrected from:
Once the filter has thawed, begin the first of two incubations: one to lyse the cells and remove RNA, and one to break down proteins. For the first incubation, add 100 &#956;l lysozyme (125 mg in 1000 &#956;l TE) and 20 ml RNase A (10 &#956;g/ml) to the filter. Reseal the filter with Parafilm and leave it to rotate in the hybridization oven at 37&#176;C for 1 hour.
to:
Once the filter has thawed, begin the first of two incubations: one to lyse the cells and remove RNA, and one to break down proteins. For the first incubation, add 100 &#956;l lysozyme (125 mg in 1000 &#956;l TE) and 20 &#956;l RNase A (10 &#956;g/ml) to the filter. Reseal the filter with Parafilm and leave it to rotate in the hybridization oven at 37&#176;C for 1 hour.

A correction was made to <a href="/video/1352">DNA Extraction from 0.22 &#181;M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation</a>. A typo in a volume's measurement was corrected in step 1.2.

Erratum: DNA Extraction from 0.22 &#181;M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation

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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>1 cc syringe (26G5/8 needle)</td>
<td>&nbsp;</td>
<td>BD</td>
<td>309597</td>
<td>&nbsp;</td>
<tr>
<td>1 ml syringe (26G5/8 needle)</td>
<td>&nbsp;</td>
<td>BD</td>
<td>309597</td>
<td>&nbsp;</td>
<tr>
<td>1.5ml eppendorf tubes</td>
<td>&nbsp;</td>
<td>Eppendorf</td>
<td>0030 125.150</td>
<td>&nbsp;</td>
<tr>
<td>15ml tubes</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>CLS430791</td>
<td>&nbsp;</td>
<tr>
<td>5cc syringe</td>
<td>&nbsp;</td>
<td>BD</td>
<td>309603</td>
<td>&nbsp;</td>
<tr>
<td>Amicon&reg; Ultra-4 Centrifugal Filter Devices</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>UFC801096</td>
<td>10,000 Nominal molecular weight limit</td>
</tr>
<tr>
<td>Butanol</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>A383-1</td>
<td>Make it water saturated (butanol:water = 1:1)</td>
</tr>
<tr>
<td>Centrifuge rotor, JA5.3 </td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>368690</td>
<td>&nbsp;</td>
<tr>
<td>Centrifuge, Avanti&reg; J-E</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>369003</td>
<td>&nbsp;</td>
<tr>
<td>Cesium chloride</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>C4036</td>
<td>&nbsp;</td>
<tr>
<td>Chloroform:IAA (24:1)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>25666-500ML</td>
<td>&nbsp;</td>
<tr>
<td>Ethidium Bromide (EtBr)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>E1510-10ml</td>
<td>&nbsp;</td>
<tr>
<td>Ethylenediaminetetraacetic acid disodium salt dihydrate</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>E5134</td>
<td>&nbsp;</td>
<tr>
<td>Hybridization oven</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>13-247-10</td>
<td>37&deg;C & 55&deg;C</td>
</tr>
<tr>
<td>Lysis Buffer</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>0.75 M sucrose, 40 mM EDTA, 50 mM Tris (pH 8.3)</td>
</tr>
<tr>
<td>Lysozyme</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>L6876-5G</td>
<td>125 mg in 1000 &mu;l TE</td>
</tr>
<tr>
<td>Microcon&reg; Ultracel YM-30 Centrifugal Filter Unit</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>42410</td>
<td>50 bp cut off</td>
</tr>
<tr>
<td>Parafilm</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>13-374-10</td>
<td>&nbsp;</td>
<tr>
<td>Phenol:Chloroform:IAA (25:24:1)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>77617-500ML</td>
<td>&nbsp;</td>
<tr>
<td>Proteinase K</td>
<td>&nbsp;</td>
<td>Qiagen</td>
<td>19133</td>
<td>&nbsp;</td>
<tr>
<td>RNase A</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>BP2539-100</td>
<td>10 &mu;g/ml</td>
</tr>
<tr>
<td>Safe Imager&trade; Blue light transilluminator</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>S37102</td>
<td>&nbsp;</td>
<tr>
<td>Sodium Dodecyl Sulfate (SDS)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>L4509</td>
<td>20% SDS</td>
</tr>
<tr>
<td>Sterivex filters</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>SVG010RS</td>
<td>&nbsp;</td>
<tr>
<td>Sucrose</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>S0389</td>
<td>&nbsp;</td>
<tr>
<td>Table top centrifuge</td>
<td>&nbsp;</td>
<td>Eppendorf</td>
<td>5415D</td>
<td>&nbsp;</td>
<tr>
<td>TE buffer, pH 8.0</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Trizma&reg; base</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>T1503</td>
<td>&nbsp;</td>
<tr>
<td>Ultracentrifuge rotor, TLA 100</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>343847</td>
<td>&nbsp;</td>
<tr>
<td>Ultracentrifuge tube (7X20mm, PC)</td>
<td>&nbsp;</td>
<td>Beckman</td>
<td>343775</td>
<td>&nbsp;</td>
<tr>
<td>Ultracentrifuge tube rack</td>
<td>&nbsp;</td>
<td>Beckman</td>
<td>348302</td>
<td>&nbsp;</td>
<tr>
<td>Ultracentrifuge, Optima&reg; Max</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
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dna extraction from 0.22 &mu;m sterivex filters and cesium chloride density gradient centrifugation

这种方法是使用0.22微米Sterivex已存储/裂解液治疗，并存档于-80 ° C过滤器浮游生物质集中超高分子量基因组DNA提取和净化使用氯化铯密度梯度，这种DNA。该协议开始有两个小时的孵化步骤，从细胞中解放出来的DNA和删除的RNA。接下来，进行一系列的酚：氯仿和氯仿抽提随后通过离心去除蛋白质和细胞膜的成分，收集水的DNA提取液，清洗和集中提取的几个缓冲交换步骤。第五部分介绍了通过氯化铯密度梯度可选净化。建议工作在同一时间少于15个样品，以避免混乱和削减协议的时间。本议定书所需的总时间取决于要提取的样品的数量。 10-15个样本，并假设适当的离心设备，整个协议应采取3天。确保你有杂交的过程开始时设置温度的烤炉。

Watch this Scientific Journal Video about DNA Extraction from 0.22 Î¼M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation at JoVE.com

DNA Extraction from 0.22 &amp;mu;M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation

我们描述了一个超高分子量从浮游生物的生物量基因组集中Sterivex 0.22微米的过滤器，氯化铯密度梯度离心纯化的DNA提取方法。

从0.22微米Sterivex过滤器和氯化铯密度梯度离心法的DNA提取

This method is used to extract high molecular weight genomic DNA from planktonic biomass concentrated on 0.22 &mu;M Sterivex filters that have been ...

dna-extraction-from-022-m-sterivex-filters-cesium-chloride-density

Research

JoVE Journal

Biology

DNA Extraction from 0.22 &mu;M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation

29.0K 次观看.  University of British Columbia - UBC. 我们描述了一个超高分子量从浮游生物的生物量基因组集中Sterivex 0.22微米的过滤器，氯化铯密度梯度离心纯化的DNA提取方法。

视频: DNA Extraction from 0.22 &mu;M Sterivex Filters and Cesium Chloride Density Gradient Centrifugation

Extraction of High Molecular Weight Genomic DNA from Soils and Sediments

The soil microbiome is a vast and relatively unexplored reservoir of genomic diversity and metabolic innovation that is intimately associated with nutrient and energy flow within terrestrial ecosystems. Cultivation-independent environmental genomic, also known as metagenomic, approaches promise unprecedented access to this genetic information with respect to pathway reconstruction and functional screening for high value therapeutic and biomass conversion processes. However, the soil microbiome still remains a challenge largely due to the difficulty in obtaining high molecular weight DNA of sufficient quality for large insert library production. Here we introduce a protocol for extracting high molecular weight, microbial community genomic DNA from soils and sediments. The quality of isolated genomic DNA is ideal for constructing large insert environmental genomic libraries for downstream sequencing and screening applications. 
The procedure starts with cell lysis. Cell walls and membranes of microbes are lysed by both mechanical (grinding) and chemical forces (&beta;-mercaptoethanol). Genomic DNA is then isolated using extraction buffer, chloroform-isoamyl alcohol and isopropyl alcohol. The buffers employed for the lysis and extraction steps include guanidine isothiocyanate and hexadecyltrimethylammonium bromide (CTAB) to preserve the integrity of the high molecular weight genomic DNA. Depending on your downstream application, the isolated genomic DNA can be further purified using cesium chloride (CsCl) gradient ultracentrifugation, which reduces impurities including humic acids. The first procedure, extraction, takes approximately 8 hours, excluding DNA quantification step. The CsCl gradient ultracentrifugation, is a two days process. During the entire procedure, genomic DNA should be treated gently to prevent shearing, avoid severe vortexing, and repetitive harsh pipetting.

A methodology to isolate high molecular weight and high quality genomic DNA from soil microbial community is described.

超高分子量基因组DNA的提取土壤和沉积物

The soil microbiome is a vast and relatively unexplored reservoir of genomic diversity and metabolic innovation that is intimately associated with ...

科研

生物学

DNA Extraction from Paraffin Embedded Material for Genetic and Epigenetic Analyses

Disease development and progression are characterized by frequent genetic and epigenetic aberrations including chromosomal rearrangements, copy number gains and losses and DNA methylation. Advances in high-throughput, genome-wide profiling technologies, such as microarrays, have significantly improved our ability to identify and detect these specific alterations. However as technology continues to improve, a limiting factor remains sample quality and availability. Furthermore, follow-up clinical information and disease outcome are often collected years after the initial specimen collection. Specimens, typically formalin-fixed and paraffin embedded (FFPE), are stored in hospital archives for years to decades. DNA can be efficiently and effectively recovered from paraffin-embedded specimens if the appropriate method of extraction is applied. High quality DNA extracted from properly preserved and stored specimens can support quantitative assays for comparisons of normal and diseased tissues and generation of genetic and epigenetic signatures 1. To extract DNA from paraffin-embedded samples, tissue cores or microdissected tissue are subjected to xylene treatment, which dissolves the paraffin from the tissue, and then rehydrated using a series of ethanol washes. Proteins and harmful enzymes such as nucleases are subsequently digested by proteinase K. The addition of lysis buffer, which contains denaturing agents such as sodium dodecyl sulfate (SDS), facilitates digestion 2. Nucleic acids are purified from the tissue lysate using buffer-saturated phenol and high speed centrifugation which generates a biphasic solution. DNA and RNA remain in the upper aqueous phase, while proteins, lipids and polysaccharides are sequestered in the inter- and organic-phases respectively. Retention of the aqueous phase and repeated phenol extractions generates a clean sample. Following phenol extractions, RNase A is added to eliminate contaminating RNA. Additional phenol extractions following incubation with RNase A are used to remove any remaining enzyme. The addition of sodium acetate and isopropanol precipitates DNA, and high speed centrifugation is used to pellet the DNA and facilitate isopropanol removal. Excess salts carried over from precipitation can interfere with subsequent enzymatic assays, but can be removed from the DNA by washing with 70% ethanol, followed by centrifugation to re-pellet the DNA 3. DNA is re-suspended in distilled water or the buffer of choice, quantified and stored at -20&deg;C. Purified DNA can subsequently be used in downstream applications which include, but are not limited to, PCR, array comparative genomic hybridization 4 (array CGH), methylated DNA Immunoprecipitation (MeDIP) and sequencing, allowing for an integrative analysis of tissue/tumor samples.

This video demonstrates the protocol for DNA extraction from formalin-fixed paraffin-embedded material. This is a multi-day procedure in which tissue sections are deparaffinized with xylene, rehydrated with ethanol and treated with proteinase K to purify and isolate DNA for subsequent gene-specific or genome-wide analysis.

从石蜡包埋材料的遗传和表观遗传分析的DNA提取

Disease development and progression are characterized by frequent genetic and epigenetic aberrations including chromosomal rearrangements, copy number ...

Extraction of High Molecular Weight DNA from Microbial Mats

Successful and accurate analysis and interpretation of metagenomic data is dependent upon the efficient extraction of high-quality, high molecular weight (HMW) community DNA. However, environmental mat samples often pose difficulties to obtaining large concentrations of high-quality, HMW DNA. Hypersaline microbial mats contain high amounts of extracellular polymeric substances (EPS)1 and salts that may inhibit downstream applications of extracted DNA. Direct and harsh methods are often used in DNA extraction from refractory samples. These methods are typically used because the EPS in mats, an adhesive matrix, binds DNA2,3 during direct lysis. As a result of harsher extraction methods, DNA becomes fragmented into small sizes4,5,6.
The DNA thus becomes inappropriate for large-insert vector cloning. In order to circumvent these limitations, we report an improved methodology to extract HMW DNA of good quality and quantity from hypersaline microbial mats. We employed an indirect method involving the separation of microbial cells from the background mat matrix through blending and differential centrifugation. A combination of mechanical and chemical procedures was used to extract and purify DNA from the extracted microbial cells. Our protocol yields approximately 2 &mu;g of HMW DNA (35-50 kb) per gram of mat sample, with an A260/280 ratio of 1.6. Furthermore, amplification of 16S rRNA genes7 suggests that the protocol is able to minimize or eliminate any inhibitory effects of contaminants. Our results provide an appropriate methodology for the extraction of HMW DNA from microbial mats for functional metagenomic studies and may be applicable to other environmental samples from which DNA extraction is challenging.

We provide an improved protocol for extracting high molecular weight DNA from hypersaline microbial mats. Microbial cells are separated from the mat matrix prior to DNA extraction and purification. This enhances the concentrations, quality, and size of the DNA. The protocol may be used for other refractory samples.

超高分子量DNA提取微生物席

Successful and accurate analysis and interpretation of metagenomic data is dependent upon the efficient extraction  of high-quality, high molecular weight ...

The Infiltration-centrifugation Technique for Extraction of Apoplastic Fluid from Plant Leaves Using Phaseolus vulgaris as an Example

The apoplast is a distinct extracellular compartment in plant tissues that lies outside the plasma membrane and includes the cell wall. The apoplastic compartment of plant leaves is the site of several important biological processes, including cell wall formation, cellular nutrient and water uptake and export, plant-endophyte interactions and defence responses to pathogens. The infiltration-centrifugation method is well established as a robust technique for the analysis of the soluble apoplast composition of various plant species. The fluid obtained by this method is commonly known as apoplast washing fluid (AWF). The following protocol describes an optimized vacuum infiltration and centrifugation method for AWF extraction from Phaseolus vulgaris (French bean) cv. Tendergreen leaves. The limitations of this method and the optimization of the protocol for other plant species are discussed. Recovered AWF can be used in a wide range of downstream experiments that seek to characterize the composition of the apoplast and how it varies in response to plant species and genotype, plant development and environmental conditions, or to determine how microorganisms grow in apoplast fluid and respond to changes in its composition.

The Infiltration-centrifugation Technique for Extraction of Apoplastic Fluid from Plant Leaves Using Phaseolus vulgaris as an Example

This protocol details the optimized extraction of apoplast washing fluid from plant leaves, using French bean plants (Phaseolus vulgaris) as a model example.

渗透离心技术质外体中提取植物液使用叶<em&gt;菜豆</em&gt;为例

The apoplast is a distinct extracellular compartment in plant tissues that lies outside the plasma membrane and includes the cell wall. The apoplastic ...

A Hybrid DNA Extraction Method for the Qualitative and Quantitative Assessment of Bacterial Communities from Poultry Production Samples

The efficacy of DNA extraction protocols can be highly dependent upon both the type of sample being investigated and the types of downstream analyses performed. Considering that the use of new bacterial community analysis techniques (e.g., microbiomics, metagenomics) is becoming more prevalent in the agricultural and environmental sciences and many environmental samples within these disciplines can be physiochemically and microbiologically unique (e.g., fecal and litter/bedding samples from the poultry production spectrum), appropriate and effective DNA extraction methods need to be carefully chosen. Therefore, a novel semi-automated hybrid DNA extraction method was developed specifically for use with environmental poultry production samples. This method is a combination of the two major types of DNA extraction: mechanical and enzymatic. A two-step intense mechanical homogenization step (using bead-beating specifically formulated for environmental samples) was added to the beginning of the &#8220;gold standard&#8221; enzymatic DNA extraction method for fecal samples to enhance the removal of bacteria and DNA from the sample matrix and improve the recovery of Gram-positive bacterial community members. Once the enzymatic extraction portion of the hybrid method was initiated, the remaining purification process was automated using a robotic workstation to increase sample throughput and decrease sample processing error. In comparison to the strict mechanical and enzymatic DNA extraction methods, this novel hybrid method provided the best overall combined performance when considering quantitative (using 16S rRNA qPCR) and qualitative (using microbiomics) estimates of the total bacterial communities when processing poultry feces and litter samples.

A novel semi-automated hybrid DNA extraction method for use with environmental poultry production samples was developed and demonstrated improvements over a common mechanical and enzymatic extraction method in terms of the quantitative and qualitative estimates of the total bacterial communities.

一种混合DNA提取方法细菌群落的定性和定量评估，从家禽生产样品

The efficacy of DNA extraction protocols can be highly dependent upon both the type of sample being investigated and the types of downstream analyses ...

Filtration Isolation of Nucleic Acids:  A Simple and Rapid DNA Extraction Method

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad to extract cellular DNA from whole blood in less than 2 min. The blood specimen is treated with detergent, mixed briefly and applied by pipet to the separation membrane. The lysate wicks into the blotting pad due to capillary action, capturing the genomic DNA on the surface of the separation membrane. The extracted DNA is retained on the membrane during a simple wash step wherein PCR inhibitors are wicked into the absorbent blotting pad. The membrane containing the entrapped DNA is then added to the PCR reaction without further purification. This simple method does not require laboratory equipment and can be easily implemented with inexpensive laboratory supplies. Here we describe a protocol for highly sensitive detection and quantitation of HIV-1 proviral DNA from 100 &#181;l whole blood as a model for early infant diagnosis of HIV that could readily be adapted to other genetic targets.

We describe here a simple and rapid paper-based DNA extraction method of HIV proviral DNA from whole blood detected by quantitative PCR. This protocol can be extended for use in detecting other genetic markers or using alternative amplification methods.

核酸的分离过滤：一种简单快速的DNA提取方法

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad ...

Sperm Collection of Differential Quality Using Density Gradient Centrifugation

In sexual reproduction, a male gamete or sperm cell fuses with a female gamete to bring about fertilization. However, a large number of sperm cells with fertilizing ability are required to interact with a female gamete to ensure fertilization. As such, the fertilizing ability of individual sperm cells is critical for successful reproduction. Density gradient centrifugation has been utilized for several decades as a reproducible, fast, efficient, effective and extremely adaptable method to collect only high-quality sperm to be used in assisted reproductive technology. The protocols we described herein focus on the utilization of the discontinuous Percoll density gradient centrifugation (PDGC) technique to isolate three distinct populations of rooster sperm by their quality. We were able to collect low-, medium- and high-quality sperm. We also describe reproducible protocols that entail determining fertility potential of sperm by assessing their viability, mobility and penetrability. Collection of sperm by their quality using PDGC technique would be useful to accurately and thoroughly characterize sperm with differential fertility potential.

In this paper, we aim to describe the performance of the density gradient centrifugation technique and its application in sperm physiology research.

密度梯度离心法测定微分品质的精子

In sexual reproduction, a male gamete or sperm cell fuses with a female gamete to bring about fertilization. However, a large number of sperm cells with ...

Small-Scale Extraction of Caenorhabditis elegans Genomic DNA

Genomic DNA extraction from single or a few Caenorhabditis elegans has many downstream applications, including PCR for genotyping lines, cloning, and sequencing. The traditional proteinase K-based methods for genomic DNA extraction from C. elegans take several hours. Commercial extraction kits that effectively break open the C. elegans cuticle and extract genomic DNA are limited. An easy, faster (~15 min), and cost-efficient method of extracting C. elegans genomic DNA that works well for classroom and research applications is reported here. This DNA extraction method is optimized to use single or a few late-larval (L4) or adult nematodes as starting material for obtaining a reliable template to perform PCR. The results indicate that the DNA quality is suitable for amplifying gene targets of different sizes by PCR, permitting genotyping of single or a few animals even at dilutions to one-fiftieth of the genomic DNA from a single adult per reaction. The reported protocols can be reliably used to quickly produce DNA template from a single or a small sample of C. elegans for PCR-based applications.

Small-Scale Extraction of Caenorhabditis elegans Genomic DNA

Presented here is a description of the straightforward and relatively rapid isolation of Caenorhabditis elegans genomic DNA from one or a few animals using a commercially available tissue kit. The resulting gDNA preparation is a suitable template for PCR.

小规模提取 秀丽隐杆线虫 基因组DNA

Genomic DNA extraction from single or a few Caenorhabditis elegans has many downstream applications, including PCR for genotyping lines, cloning, and ...

用于微生物群多组学的增强细菌细胞外囊泡分离

Isolation and Purification of Bacterial Extracellular Vesicles from Human Feces Using Density Gradient Centrifugation

Bacterial extracellular vesicles (BEVs) are nanovesicles derived from bacteria that play an active role in bacteria-bacteria and bacteria-host communication, transferring bioactive molecules such as proteins, lipids, and nucleic acids inherited from the parent bacteria. BEVs derived from the gut microbiota have effects within the gastrointestinal tract and can reach distant organs, resulting in significant implications for physiology and pathology. Theoretical investigations that explore the types, quantities, and roles of BEVs derived from human feces are crucial for understanding the secretion and function of BEVs from the gut microbiota. These investigations also necessitate an improvement in the current strategy for isolating and purifying BEVs.
This study optimized the isolation and purification process of BEVs by establishing two density gradient centrifugation (DGC) modes: Top-down and Bottom-up. The enriched distribution of BEVs was determined in fractions 6 to 8 (F6-F8). The effectiveness of the approach was evaluated based on particle morphology, size, concentration, and protein content. The particle and protein recovery rates were calculated, and the presence of specific markers was analyzed to compare the recovery and purity of the two DGC modes. The results indicated that the Top-down centrifugation mode had lower contamination levels and achieved a recovery rate and purity similar to that of the Bottom-up mode. A centrifugation time of 7 h was sufficient to achieve a fecal BEV concentration of 108/mg.
Apart from feces, this method could be applied to other body fluid types with proper modification according to the differences in components and viscosity. In conclusion, this detailed and reliable protocol would facilitate the standardized isolation and purification of BEVs and thus, lay a foundation for subsequent multi-omics analysis and functional experiments.

作者聚焦：加速细菌细胞外囊泡分离和异质性的研究 

This study describes a method to isolate and purify bacterial extracellular vesicles (BEVs) enriched from human feces via density gradient centrifugation (DGC), identifies the physical characteristics of BEVs from morphology, particle size, and concentration, and discusses the potential applications of the DGC approach in clinical and scientific research.