This work was supported by Strategic Project and Discovery Grants to J.D.N. from the Natural Sciences and Engineering Research Council of Canada (NSERC).

1. Preparation of Reagents
DNA-SIP requires the use of reagents that should be prepared in advance of the actual procedure. The directions for preparing each reagent are listed in this section and are modified from a previous SIP protocol1.
<ol>
 <li>Cesium chloride (CsCl) solution for preparing SIP gradients - Prepare a 7.163 M CsCl solution by gradually dissolving 603.0 g of CsCl in distilled and deionized water (ddH2O) to a final volume of 500 mL. Be careful n...

<ol>
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E., Chistoserdova, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+populations+active+in+metabolism+of+C1+compounds+in+the+sediment+of+Lake+Washington,+a+freshwater+lake.">Bacterial populations active in metabolism of C1 compounds in the sediment of Lake Washington, a freshwater lake.</a> Appl. Environ. Microbiol. 71, 6885-6899 (2005).</li><li>Padmanabhan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Respiration+of+13C-labelled+substrates+added+to+soil+in+the+field+and+subsequent+16S+rRNA+gene+analysis+of+13C-labelled+soil+DNA.">Respiration of 13C-labelled substrates added to soil in the field and subsequent 16S rRNA gene analysis of 13C-labelled soil DNA.</a> Appl. Environ. Microbiol. 69, 1614-1622 (2003).</li><li>Bernard, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+and+identification+of+soil+microbial+populations+actively+assimilating+carbon+from+13C-labelled+wheat+residue+as+estimated+by+DNA-+and+RNA-SIP+techniques.">Dynamics and identification of soil microbial populations actively assimilating carbon from 13C-labelled wheat residue as estimated by DNA- and RNA-SIP techniques.</a> Environ. Microbiol. 9, 752-764 (2007).</li><li>Haichar, e. l. Z. a. h. a. r., F, . <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+cellulolytic+bacteria+in+soil+by+stable+isotope+probing.">Identification of cellulolytic bacteria in soil by stable isotope probing.</a> Environ. Microbiol. 9, 625-634 (2007).</li><li>Addison, S., McDonald, I., Lloyd-Jones, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+isotope+probing:+Technical+considerations+when+resolving+15N-labelled+RNA+in+gradients.">Stable isotope probing: Technical considerations when resolving 15N-labelled RNA in gradients.</a> J. Microbiol. Meth. 80, 70-75 (2009).</li><li>Buckley, D. H., Huangyutitham, V., Hsu, S. -. F., Nelson, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+isotope+probing+with+15N+achieved+by+disentangling+the+effects+of+genome+G+++C+content+and+isotope+enrichment+on+DNA+density.">Stable isotope probing with 15N achieved by disentangling the effects of genome G + C content and isotope enrichment on DNA density.</a> Appl. Environ. Microbiol. 73, 3189-3195 (2007).</li><li>Schwartz, E. <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+growing+microorganisms+in+soil+by+stable+isotope+probing+with+H218O.">Characterization of growing microorganisms in soil by stable isotope probing with H218O.</a> Appl. Environ. Microbiol. 73, 2541-2546 (2007).</li><li>Neufeld, J. D., Dumont, M. G., Vohra, J., Murrell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methodological+considerations+for+the+use+of+stable+isotope+probing+in+microbial+ecology.">Methodological considerations for the use of stable isotope probing in microbial ecology.</a> Microb. Ecol. 53, 435-442 (2007).</li><li>Martineau, C., Whyte, L., Greer, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+SYBR+safe+technique+for+the+sensitive+detection+of+DNA+in+cesium+chloride+density+gradients+for+stable+isotope+probing+assays.">Development of a SYBR safe technique for the sensitive detection of DNA in cesium chloride density gradients for stable isotope probing assays.</a> J. Microbiol. Meth. 73, 199-202 (2008).</li><li>Bartram, A. K., Poon, C., Neufeld, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nucleic+acid+contamination+of+glycogen+used+in+nucleic+acid+precipitation+and+assessment+of+linear+polyacrylamide+as+an+alternative+co-precipitant.">Nucleic acid contamination of glycogen used in nucleic acid precipitation and assessment of linear polyacrylamide as an alternative co-precipitant.</a> Biotechniques. 47, 1019-1022 (2009).</li><li>Chen, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Revealing+the+uncultivated+majority:+combining+DNA+stable-isotope+probing,+multiple+displacement+amplification+and+metagenomic+analyses+of+uncultivated+Methylocystis+in+acidic+peatlands.">Revealing the uncultivated majority: combining DNA stable-isotope probing, multiple displacement amplification and metagenomic analyses of uncultivated Methylocystis in acidic peatlands.</a> Environ. Microbiol. 10, 2609-2622 (2008).</li><li>Neufeld, J. D., Chen, Y., Dumont, M. G., Murrell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marine+methylotrophs+revealed+by+stable-isotope+probing,+multiple+displacement+amplification+and+metagenomics.">Marine methylotrophs revealed by stable-isotope probing, multiple displacement amplification and metagenomics.</a> Environ. Microbiol. 10, 1526-1535 (2008).</li><li>Kalyuzhnaya, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+metagenomics+targets+specific+functional+types+in+complex+microbial+communities.">High-resolution metagenomics targets specific functional types in complex microbial communities.</a> Nat. Biotechnol. 26, 1029-1034 (2008).</li><li>Binga, E. K., Lasken, R. S., Neufeld, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Something+from+(almost)+nothing:+the+impact+of+multiple+displacement+amplification+on+microbial+ecology.">Something from (almost) nothing: the impact of multiple displacement amplification on microbial ecology.</a> ISME J. 2, 233-241 (2008).</li><li>Green, S. J., Leigh, M. B., Neufeld, J. D., Timmis, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Microbiology of Hydrocarbon and Lipid Microbiology. , 4137-4158 (2010).</li><li>Neufeld, J. D., Wagner, M., Murrell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Who+eats+what,+where+and+when?+Isotope-labelling+experiments+are+coming+of+age.">Who eats what, where and when? Isotope-labelling experiments are coming of age.</a> ISME J. 1, 103-110 (2007).</li><li>Gallagher, E., McGuinness, L., Phelps, C., Young, L. Y., Kerkhof, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DNA+shortens+the+incubation+time+needed+to+detect+benzoate-utilizing+denitrifying+bacteria+by+stable-isotope+probing.">DNA shortens the incubation time needed to detect benzoate-utilizing denitrifying bacteria by stable-isotope probing.</a> Appl. Environ. Microbiol. 71, 5192-5196 .</li></ol>

No conflicts of interest declared.

Proper design of stable-isotope probing experiments is of critical importance for obtaining labelled DNA above the background unlabelled community. Considerations related to sample incubation times, substrate concentrations, incubation conditions (e.g. nutrients, soil moisture content), cross-feeding and replication have been discussed elsewhere 10,18 and we recommend the reader consult these publications when designing a SIP incubation. Related to the current protocol, it is worth commenting on additional con...

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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>Bromophenol Blue</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>BP115-25</td>
<td>&nbsp;</td>
<tr>
<td>Cesium chloride</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>BP210-500</td>
<td>&nbsp;</td>
<tr>
<td>Ethanol, reagent grade</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>652261</td>
<td>&nbsp;</td>
<tr>
<td>Ethidium bromide</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>E1510</td>
<td>&nbsp;</td>
<tr>
<td>Hydrochloric acid</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>351285212</td>
<td>&nbsp;</td>
<tr>
<td>Linear polyacrylamide</td>
<td>Reagent</td>
<td>Applichem</td>
<td>A6587</td>
<td>&nbsp;</td>
<tr>
<td>Polyethylene Glycol 6000</td>
<td>Reagent</td>
<td>VWR</td>
<td>CAPX1286L-4</td>
<td>&nbsp;</td>
<tr>
<td>Potassium Chloride</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>AC42409-0010</td>
<td>&nbsp;</td>
<tr>
<td>Sodium Chloride</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>S2711</td>
<td>&nbsp;</td>
<tr>
<td>Sodium Hydroxide pellets</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>S3181</td>
<td>&nbsp;</td>
<tr>
<td>Tris base</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>BP1521</td>
<td>&nbsp;</td>
<tr>
<td>Dark Reader</td>
<td>Equipment</td>
<td>Clare Chemical</td>
<td>DR46B</td>
<td>&nbsp;</td>
<tr>
<td>Microcentrifuge</td>
<td>Equipment</td>
<td>Eppendorf</td>
<td>5424 000.410</td>
<td>&nbsp;</td>
<tr>
<td>Nanodrop 2000</td>
<td>Equipment</td>
<td>Fisher Scientific</td>
<td>361013650</td>
<td>&nbsp;</td>
<tr>
<td>Infusion pump</td>
<td>Equipment</td>
<td>Braintree Scientific</td>
<td>N/A</td>
<td>Model Number: BSP 
See <a href="http://www.braintreesci.com">www.braintreesci.com</a> for ordering details.</td>
</tr>
<tr>
<td>Tube sealer</td>
<td>Equipment</td>
<td>Beckman-Coulter</td>
<td>358312</td>
<td>&nbsp;</td>
<tr>
<td>Ultracentrifuge</td>
<td>Equipment</td>
<td>Beckman-Coulter</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ultracentrifuge rotor</td>
<td>Equipment</td>
<td>Beckman-Coulter</td>
<td>362754</td>
<td>&nbsp;</td>
<tr>
<td>Ultraviolet light source</td>
<td>Equipment</td>
<td>UVP Inc. </td>
<td>95-0017-09</td>
<td>Any UV source will suffice</td>
</tr>
<tr>
<td>Ultraviolet light face shield</td>
<td>Equipment</td>
<td>Fisher Scientific</td>
<td>114051C</td>
<td>&nbsp;</td>
<tr>
<td>Butyl rubber stoppers, gray</td>
<td>Material</td>
<td>Sigma-Aldrich</td>
<td>27232</td>
<td>&nbsp;</td>
<tr>
<td>Centrifuge tubes</td>
<td>Material</td>
<td>Beckman-Coulter</td>
<td>342412</td>
<td>&nbsp;</td>
<tr>
<td>Hypodermic needle, 23 gauge, 2&#x201D; length</td>
<td>Material</td>
<td>BD</td>
<td>305145</td>
<td>&nbsp;</td>
<tr>
<td>Microfuge tubes, 1.5 mL</td>
<td>Material</td>
<td>DiaMed</td>
<td>AD151-N500</td>
<td>&nbsp;</td>
<tr>
<td>Open center seals, 20 mm diameter</td>
<td>Material</td>
<td>Sigma-Aldrich</td>
<td>27230-U</td>
<td>&nbsp;</td>
<tr>
<td>Pasteur pipettes, glass</td>
<td>Material</td>
<td>Fisher Scientific</td>
<td>13-678-6C</td>
<td>&nbsp;</td>
<tr>
<td>Pipet tips</td>
<td>Material</td>
<td>DiaMed</td>
<td>BPS340-1000 </td>
<td>Catalogue number is for 200 &mu;l tips. 10 or 20 &mu;l tips may be purchased from the same source</td>
</tr>
<tr>
<td>Pump tubing 1.5 mm bore x 1.5 mm wall</td>
<td>Material</td>
<td>Appleton Woods</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Screw-cap tubes, 15 mL</td>
<td>Material</td>
<td>DiaMed</td>
<td>AD15MLP-S </td>
<td>&nbsp;</td>
<tr>
<td>Serum vials, 125 mL volume</td>
<td>Material</td>
<td>Sigma-Aldrich</td>
<td>Z114014</td>
<td>&nbsp;</td>
<tr>
<td>Syringe, 60 mL</td>
<td>Material</td>
<td>BD</td>
<td>309653</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

dna stable-isotope probing (dna-sip)

DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and nutrients into cellular biomass. As such, this cultivation-independent technique has been an important methodology for assigning metabolic function to the diverse communities inhabiting a wide range of terrestrial and aquatic environments. Following the incubation of an environmental sample with stable-isotope labelled compounds, extracted nucleic acid is subjected to density gradient ultracentrifugation and subsequent gradient fractionation to separate nucleic acids of differing densities. Purification of DNA from cesium chloride retrieves labelled and unlabelled DNA for subsequent molecular characterization (e.g. fingerprinting, microarrays, clone libraries, metagenomics). This JoVE video protocol provides visual step-by-step explanations of the protocol for density gradient ultracentrifugation, gradient fractionation and recovery of labelled DNA. The protocol also includes sample SIP data and highlights important tips and cautions that must be considered to ensure a successful DNA-SIP analysis.

Watch this Scientific Journal Video about DNA Stable-Isotope Probing DNA-SIP at JoVE.com

DNA Stable-Isotope Probing DNA-SIP

DNA stable-isotope probing is a cultivation-independent method to identify and characterize active communities of microorganisms that are capable of utilizing specific substrates. Assimilation of substrate enriched in heavy isotope leads to incorporation of labelled atoms into microbial biomass. Density gradient ultracentrifugation retrieves labelled DNA for downstream molecular analyses.

DNA Stable-Isotope Probing (DNA-SIP)

DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and ...

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Biology

43.5K Views.  University of Waterloo. DNA stable-isotope probing is a cultivation-independent method to identify and characterize active communities of microorganisms that are capable of utilizing specific substrates. Assimilation of substrate enriched in heavy isotope leads to incorporation of labelled atoms into microbial biomass. Density gradient ultracentrifugation retrieves labelled DNA for downstream molecular analyses.