Name: aseptic laboratory techniques: plating methods
Uploaded: 2012-05-11T12:00:00
Duration: 18 min
Description: Watch this Scientific Journal Video about Aseptic Laboratory Techniques: Plating Methods at JoVE.com

<p class="jove_content">Special thanks to Cori Sanders at Iroc Designs for preparing illustrations and to Kris Reddi and Bhairav Shah at UCLA for setting up sample cultures and assisting with figures. Funding for this project was provided by HHMI (HHMI Grant No. 52006944).</p>

<ol>
	<li>Barker, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>At the Bench: A Laboratory Navigator</em>. , (1998).</li><li>US Department of Health and Human Services (DHHS). <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Biosafety in Microbiological And Biomedical Laboratories (BMBL)</em>. , (2009).</li><li>Dulbecco, R., Vogt, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Some+problems+of+animal+virology+as+studied+by+the+plaque+technique.">Some problems of animal virology as studied by the plaque technique.</a> <em style='font-style: italic'>Cold Spring Harbor Symp. Quant. Biol</em>. <b>18</b>, 273-279 (1953).</li><li>Fields, B. N., Knipe, D. M., Chanock, R. M., Hirsch, M. S., Melnick, J. L., Monath, T. P., Roizman, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Fields Virology</em>. <b>1</b>, (1991).</li><li>Gilbert, R. A., Ouwerkerk, D., Zhang, L. H., Klieve, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cooperative+Research+Center+for+Beef+Genetic+Technologies.+In+vitro+detection+and+primary+cultivation+of+bacteria+producing+materials+inhibitory+to+ruminal+methanogens.">Cooperative Research Center for Beef Genetic Technologies. In vitro detection and primary cultivation of bacteria producing materials inhibitory to ruminal methanogens.</a> <em style='font-style: italic'>Journal of Microbiological Methods</em>. <b>80</b>, 217-218 (2010).</li><li>Jett, B. D., Hatter, K. L., Huycke, M. M., Gilmore, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simplified+agar+plate+method+for+quantifying+viable+bacteria.">Simplified agar plate method for quantifying viable bacteria.</a> <em style='font-style: italic'>BioTechniques</em>. <b>23</b>, 648-650 (1997).</li><li>Karam, 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=.">.</a> <em style='font-style: italic'>Molecular Biology of Bacteriophage T4</em>. , (1994).</li><li>Knipe, D. M., Howley, P. M., Griffin, D. E., Lamb, R. A., Martin, M. A., Roizman, B., Straus, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Fundamental Virology</em>. , (2001).</li><li>Lederberg, J., Lederberg, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Replica+plating+and+indirect+selection+of+bacterial+mutants.">Replica plating and indirect selection of bacterial mutants.</a> <em style='font-style: italic'>J. Bacteriol</em>. <b>63</b>, 399-406 (1952).</li><li>Miller, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>A Short Course in Bacterial Genetics: A Laboratory Manual and Handbook for Escherichia coli and related bacteria</em>. , (1992).</li><li>Mills, K. V., Gareau, J. R., Garcia, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-cost+modification+to+the+Copacabana+method+for+spreading+transformation+mixtures.">Low-cost modification to the Copacabana method for spreading transformation mixtures.</a> <em style='font-style: italic'>BioTechniques</em>. <b>39</b>, 188 (2005).</li><li>Jordan, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>RESEARCH: National Genomics Research Initiative Phage Resource Laboratory Manual</em>. , (2008).</li><li>Sambrook, J., Russell, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Molecular Cloning - A Laboratory Manual</em>. , (2001).</li><li>Sanders, E. R., Miller, J. H. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Microbiologist: A Discovery-based Course in Microbial Ecology and Molecular Evolution</em>. , (2010).</li><li>Slonczewski, J. L., Foster, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Microbiology - An Evolving Science</em>. , (2011).</li><li>Teather, R. M., Wood, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+Congo+Red-Polysaccharide+Interactions+in+Enumeration+and+Characterization+of+Cellulolytic+Bacteria+from+the+Bovine+Rumen.">Use of Congo Red-Polysaccharide Interactions in Enumeration and Characterization of Cellulolytic Bacteria from the Bovine Rumen.</a> <em style='font-style: italic'>Applied and Environmental Microbiology</em>. <b>43</b>, 777-780 (1982).</li><li>Wise, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> <em style='font-style: italic'>Preparing Spread Plates Protocols</em>. , (2006).</li><li>Worthington, M., Luo, R. Q., Pelo, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copacabana+method+for+spreading+E.+coli+and+yeast+colonies.">Copacabana method for spreading E. coli and yeast colonies.</a> <em style='font-style: italic'>BioTechniques</em>. <b>30</b>, 738-742 (2001).</li></ol>

<p class="jove_content">I have nothing to disclose.</p>

<p class="jove_content">Culturing microorganisms involves a number of plating methods, all of which require that aseptic technique be maintained throughout the manipulation of cells and media. Five different procedures were described in this protocol. Although these plating techniques are routinely used to manipulate bacteria and phage, they also can be applied to mammalian cell culture and eukaryotic microorganisms commonly used in molecular genetics such as yeast (i.e., <em>Saccharomyces cerevisiae, Candida albicans, Schizosaccharomyces pombe</em>), algae and protozoa (i.e., <em>Volvox, Chlamydomonas, Amoeba, Paramecium</em>), and nematodes (i.e., <em>Caenorhabditis elegans</em>). There also are numerous (and even more sophisticated) variations of each plating method depending on the experimental goal or organism under study. Thus, it is important to not only select the most appropriate technique for a given experiment or target microorganism but also to tailor the methodology such that the experimental outcomes suitably address the research question or problem.</p>
<p class="jove_content">Some of the most current applications of the plating techniques discussed in this protocol involve technological advances that yield high-throughput results for screening and drug discovery experiments. For example, genome sequencing centers use the "Copacabana Method" for spread-plating clone libraries, which are <em>E. coli</em> cells transformed with plasmids containing DNA fragments derived from the genome of a microorganism. Because dozens of large plates (called bioassay trays) are prepared at once, an automated plate shaker is used to shake the glass beads for the entire batch of trays. Furthermore, when selecting colonies from these plates following incubation, a robotic colony picker is used to collect cells from appropriate colonies as the inoculum for LB broth in 384-well microplates. For this high-throughput screening assay, the procedural principles of the spread-plate technique apply but technology allows various steps to be automated and scaled to permit a large number of samples to be analyzed simultaneously and within a short time frame.</p>
<p class="jove_content">Biotechnology and pharmaceutical companies invest considerable resources in the development of high-throughput technology for the most basic techniques in microbiology and molecular genetics. For instance, there are multi-channel micropipettors to perform volume transfers for up to 8 or 12 samples at once. There even are robotic workstations that maneuver a 96-channel pipette head! These efforts involve multi-disciplinary teams of scientists, pairing biologists that possess methodological expertise with engineers and computer programmers who can develop the instrumentation needed to perform the mechanical operations associated with the experiments. Regardless of the research application, the goal shared by companies developing these technologies is the same - to automate laboratory processes, tools, systems and instruments, making them less labor intensive and more efficient.</p>

<p class="jove_step">1. Yeast Tryptone Agar (YTA)</p>
<table border="1">
	<tbody>
		<tr>
			<td>Yeast extract</td>
			<td>2.0 g</td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>10.0 g</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>15.0 g</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>up to 1000.0 ml</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>pH 7.0</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Autoclave at 121&deg;C for 20 minutes to sterilize. Store at 4&deg;C.</p>
<p class="jove_content">If preparing tubes for the pour-plate procedure, allow the agar to cool to ~55&deg;C then add 2.0 ml of 50 mg/ml cycloheximide. Aseptically dispense 18.0 ml of the melted agar per 18 mm tube then store at 4&deg;C. The agar will solidify and will need to be melted in a steamer or microwave prior to use.</p>
<p class="jove_step">2. Minimal Salts Agar (MSA) + 0.1% (w/v) carbon source</p>
<table border="1">
	<tbody>
		<tr>
			<td>NH<sub>4</sub>Cl</td>
			<td>1.0 g</td>
		</tr>
		<tr>
			<td>NH<sub>2</sub>HPO<sub>4</sub>&bull;2H<sub>2</sub>O</td>
			<td>2.14 g</td>
		</tr>
		<tr>
			<td>KH<sub>2</sub>PO<sub>4</sub></td>
			<td>1.09 g</td>
		</tr>
		<tr>
			<td>MgSO<sub>4</sub>&bull;7H<sub>2</sub>O</td>
			<td>0.2 g</td>
		</tr>
		<tr>
			<td>Carbon source*</td>
			<td>1.0 g</td>
		</tr>
		<tr>
			<td>Trace salts solution**</td>
			<td>10.0 ml</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>15.0 g</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>up to 1000.0 ml</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>pH 7.0</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Autoclave at 121&deg;C for 20 minutes to sterilize. Store at 4&deg;C.</p>
<p class="jove_content">* Carbon sources used for experiments presented in <strong>Figure 13</strong> include acetamide, lactose, and glycine.</p>
<p class="jove_content">** Trace salts solution is prepared in 0.1 N HCl as follows. It is added to the base before sterilization (autoclave at 121&deg;C for 20 minutes).</p>
<table border="1">
	<tbody>
		<tr>
			<td>FeSO<sub>4</sub>&bull;7H<sub>2</sub>O</td>
			<td>300.0 mg</td>
		</tr>
		<tr>
			<td>MnCl<sub>2</sub>&bull;4H<sub>2</sub>O</td>
			<td>180.0 mg</td>
		</tr>
		<tr>
			<td>Co(NO<sub>3</sub>)<sub>2</sub>&bull;6H<sub>2</sub>O</td>
			<td>130.0 mg</td>
		</tr>
		<tr>
			<td>ZnSO<sub>4</sub>.7H<sub>2</sub>O</td>
			<td>40.0 mg</td>
		</tr>
		<tr>
			<td>H<sub>2</sub>MoO<sub>4</sub></td>
			<td>20.0 mg</td>
		</tr>
		<tr>
			<td>CuSO<sub>4</sub>&bull;5H<sub>2</sub>O</td>
			<td>1.0 mg</td>
		</tr>
		<tr>
			<td>CaCl<sub>2</sub></td>
			<td>1000.0 mg</td>
		</tr>
		<tr>
			<td>HCl (0.1 N)</td>
			<td>up to 1000.0 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_step">3. EHA soft agar (0.65 % w/v)</p>
<table border="1">
	<tbody>
		<tr>
			<td>Agar</td>
			<td>6.5 g</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>Tryptone</td>
			<td>13.0 g</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>NaCl</td>
			<td>8.0 g</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>Na Citrate&bull;2H<sub>2</sub>O</td>
			<td>2.0 g</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>Glucose</td>
			<td>3.0 g</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>Distilled water</td>
			<td>up to 1000.0 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Autoclave at 121&deg;C for 20 minutes to sterilize. Store at 4&deg;C.</p>
<p class="jove_step">4. EHA hard agar (1.2% w/v)</p>
<table border="1">
	<tbody>
		<tr>
			<td>Agar</td>
			<td>12.0 g</td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>13.0 g</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>8.0 g</td>
		</tr>
		<tr>
			<td>Na Citrate&bull;2H<sub>2</sub>O</td>
			<td>2.0 g</td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>3.0 g</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>up to 1000.0 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Autoclave at 121&deg;C for 20 minutes to sterilize. Store at 4&deg;C.</p>
<p class="jove_step">5. 1X Middlebrook Top Agar (MBTA soft agar, 0.5% w/v)</p>
<table border="1">
	<tbody>
		<tr>
			<td>100 mM CaCl<sub>2</sub> stock*</td>
			<td>1 ml</td>
		</tr>
		<tr>
			<td>7H9 liquid medium: <em>Neat </em>**</td>
			<td>50 ml</td>
		</tr>
		<tr>
			<td>2XTA ***</td>
			<td>50 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Melt 50 ml of 2XTA and allow it to cool to ~55&deg;C. Using aseptic technique, add the CaCl<sub>2</sub> and 7H9 broth to the melted agar. Aseptically dispense 4.5 ml of the mixture per 13 mm tube and store in a 55&deg;C incubator &le;7 days. Cooling MBTA to room temperature or 4&deg;C will cause the CaCl<sub>2</sub> to precipitate out of solution.</p>
<p class="jove_content">* 100 mM CaCl<sub>2</sub>. stock must be stored at room temperature to prevent CaCl<sub>2</sub> from precipitating out of solution.</p>
<p class="jove_content">** 7H9 liquid medium: Neat</p>
<table border="1">
	<tbody>
		<tr>
			<td>7H9 broth base</td>
			<td>4.7 g</td>
		</tr>
		<tr>
			<td>40% glycerol stock</td>
			<td>5 ml</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>up to 900.0 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Mix the base with water then add the glycerol while stirring. Autoclave at 121&deg;C for 20 minutes to sterilize. Store at 4&deg;C.</p>
<p class="jove_content">*** 2X Middlebrook Top Agar (2XTA, 1.0% w/v)</p>
<table border="1">
	<tbody>
		<tr>
			<td>7H9 broth base</td>
			<td>4.7 g</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>1.0 g</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>up to 1000.0 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Autoclave at 121&deg;C for 20 minutes to sterilize. Dispense 50 ml aliquots into 100 ml bottles and store at 4&deg;C.</p>
<p class="jove_step">6. Middlebrook 7H10 Agar Plates (MHA hard agar, 1.9% w/v)</p>
<table border="1">
	<tbody>
		<tr>
			<td>7H10 agar base</td>
			<td>19.0 g</td>
		</tr>
		<tr>
			<td>40% glycerol stock</td>
			<td>12.5 ml</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>887.5 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Mix the agar base with water then add the glycerol while stirring. Heat the solution to boiling then stir for one minute to completely dissolve the base powder. Autoclave at 121&deg;C for 20 minutes to sterilize. Allow the agar to cool to ~55&deg;C then aseptically add the following reagents:</p>
<table border="1">
	<tbody>
		<tr>
			<td>AD supplement (pre-warmed to 37&deg;C)*</td>
			<td>100 ml</td>
		</tr>
		<tr>
			<td>50 mg/ml Carbenicillin **</td>
			<td>1.0 ml</td>
		</tr>
		<tr>
			<td>10 mg/ml Cycloheximide **</td>
			<td>1.0 ml</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">* AD supplement</p>
<table border="1">
	<tbody>
		<tr>
			<td>NaCl &gt;</td>
			<td>17 g &gt;</td>
		</tr>
		<tr>
			<td>Albumin (Fraction V)&gt;</td>
			<td>100 g&gt;</td>
		</tr>
		<tr>
			<td>Dextrose (<em>D</em>-Glucose)&gt;</td>
			<td>40 g&gt;</td>
		</tr>
		<tr>
			<td>Distilled water&gt;</td>
			<td>up to 2000.0 ml&gt;</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Filter-sterilize this solution; do not autoclave. Store at 4&deg;C.</p>
<p class="jove_content">** Filter-sterilize and store these solutions at 4&deg;C for &le;60 days.</p>
<p class="jove_step">7. LB agar (1.5% w/v) + X-Gal (60 &mu;g/ml)</p>
<table border="1">
	<tbody>
		<tr>
			<td>Tryptone</td>
			<td>10.0 g</td>
		</tr>
		<tr>
			<td>Yeast extract</td>
			<td>5.0 g</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>10.0 g</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>15.0 g</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>up to 1000.0 ml</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>pH 7.5 at 25&deg;C</td>
		</tr>
	</tbody>
</table>
<p class="jove_content">Autoclave at 121&deg;C for 20 minutes to sterilize. Allow the agar to cool to ~55&deg;C then aseptically add 3.0 ml of 20 mg/ml X-Gal solution. Freshly prepare X-gal stock by dissolving 400 mg X-Gal in 20 ml dimethylformamide (DMF).</p>
<p class="jove_step">Table of specific reagents:</p>
<table border="1">
	<tbody>
		<tr>
			<td><strong>Name of the reagent</strong></td>
			<td><strong>Company</strong></td>
			<td><strong>Catalogue number</strong></td>
		</tr>
		<tr>
			<td>Yeast extract</td>
			<td>Becton Dickenson</td>
			<td>212750</td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>Becton Dickenson</td>
			<td>211705</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>Becton Dickenson</td>
			<td>214030</td>
		</tr>
		<tr>
			<td>NH<sub>4</sub>Cl</td>
			<td>Acros Organics</td>
			<td>123340010</td>
		</tr>
		<tr>
			<td>NH<sub>2</sub>HPO<sub>4</sub>&bull;2H<sub>2</sub>O</td>
			<td>Sigma-Aldrich</td>
			<td>30435</td>
		</tr>
		<tr>
			<td>KH<sub>2</sub>PO<sub>4</sub></td>
			<td>Fisher Scientific</td>
			<td>BP 303-500</td>
		</tr>
		<tr>
			<td>MgSO<sub>4</sub>&bull;7H<sub>2</sub>O</td>
			<td>Sigma-Aldrich</td>
			<td>230391</td>
		</tr>
		<tr>
			<td>Acetamide</td>
			<td>Sigma-Aldrich</td>
			<td>A-0500</td>
		</tr>
		<tr>
			<td>Lactose</td>
			<td>Fisher Scientific</td>
			<td>L6-500</td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Sigma-Aldrich</td>
			<td>G-7126</td>
		</tr>
		<tr>
			<td>FeSO<sub>4</sub>&bull;7H<sub>2</sub>O</td>
			<td>Sigma-Aldrich</td>
			<td>F8048</td>
		</tr>
		<tr>
			<td>MnCl<sub>2</sub>&bull;4H<sub>2</sub>O</td>
			<td>Sigma-Aldrich</td>
			<td>M-3634</td>
		</tr>
		<tr>
			<td>Co(NO<sub>3</sub>)<sub>2</sub>&bull;6H<sub>2</sub>O</td>
			<td>Sigma-Aldrich</td>
			<td>230375</td>
		</tr>
		<tr>
			<td>ZnSO<sub>4</sub>.7H<sub>2</sub>O</td>
			<td>Sigma-Aldrich</td>
			<td>Z4750</td>
		</tr>
		<tr>
			<td>H<sub>2</sub>MoO<sub>4</sub></td>
			<td>Acros Organics</td>
			<td>213621000</td>
		</tr>
		<tr>
			<td>CuSO<sub>4</sub>&bull;5H<sub>2</sub>O</td>
			<td>Sigma-Aldrich</td>
			<td>209198</td>
		</tr>
		<tr>
			<td>CaCl<sub>2</sub></td>
			<td>Sigma-Aldrich</td>
			<td>C1016</td>
		</tr>
		<tr>
			<td>HCl</td>
			<td>Fisher Scientific</td>
			<td>A144-212</td>
		</tr>
		<tr>
			<td>Cycloheximide</td>
			<td>Sigma</td>
			<td>038K1561</td>
		</tr>
		<tr>
			<td>Carbenicillin</td>
			<td>Cellgro</td>
			<td>46-100-RG</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Fisher</td>
			<td>S271-1</td>
		</tr>
		<tr>
			<td>Na Citrate&bull;2H<sub>2</sub>O</td>
			<td>Fisher</td>
			<td>S279-500</td>
		</tr>
		<tr>
			<td>Glucose (Dextrose)</td>
			<td>BD</td>
			<td>215530</td>
		</tr>
		<tr>
			<td>7H9 broth base</td>
			<td>BD</td>
			<td>271310</td>
		</tr>
		<tr>
			<td>7H10 agar base</td>
			<td>BD</td>
			<td>262710</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Shelton</td>
			<td>IB15760</td>
		</tr>
		<tr>
			<td>Albumin (Fraction V)</td>
			<td>Fisher</td>
			<td>S71907</td>
		</tr>
		<tr>
			<td>X-Gal (5-bromo-4-chloro-3-indolyl-&beta;-D-galactopyranoside)</td>
			<td>Teknova</td>
			<td>X1205</td>
		</tr>
		<tr>
			<td>Dimethylformamide (DMF)</td>
			<td>Sigma</td>
			<td>D4551</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Fisher</td>
			<td>CDA19</td>
		</tr>
		<tr>
			<td>Chlorine Bleach</td>
			<td>Chlorox</td>
			<td>02490/06644884</td>
		</tr>
		<tr>
			<td>CiDecon (disinfectant)</td>
			<td>Decon Laboratories, Inc.</td>
			<td>8504</td>
		</tr>
	</tbody>
</table>
<p class="jove_step">Table of specific equipment:</p>
<table border="1">
	<tbody>
		<tr>
			<td><strong>Name of equipment</strong></td>
			<td><strong>Company</strong></td>
			<td><strong>Catalogue number</strong></td>
			<td><strong>Experiment</strong></td>
		</tr>
		<tr>
			<td>Metal loops</td>
			<td>American Educational Products</td>
			<td>S17352</td>
			<td> Streak plating</td>
		</tr>
		<tr>
			<td>Disposable plastic loops</td>
			<td>Fisher</td>
			<td>22-363-602</td>
			<td> Streak plating</td>
		</tr>
		<tr>
			<td>Wooden sticks</td>
			<td>Fisher</td>
			<td>23-400-104</td>
			<td> Streak plating</td>
		</tr>
		<tr>
			<td>Flat Toothpicks</td>
			<td>American Educational Products</td>
			<td>S67859</td>
			<td>Streak plating</td>
		</tr>
		<tr>
			<td>Turn tables</td>
			<td>Fisher</td>
			<td>08-758Q</td>
			<td>Spread plating</td>
		</tr>
		<tr>
			<td>Glass rods</td>
			<td>Bellco Glass</td>
			<td>NC9004380</td>
			<td>Spread plating</td>
		</tr>
		<tr>
			<td>4 mm glass beads</td>
			<td>Fisher</td>
			<td>11-312B</td>
			<td>Spread plating</td>
		</tr>
		<tr>
			<td>Velveteen cloth</td>
			<td>Bel-Art Products</td>
			<td>09-718-2</td>
			<td>Replica plating</td>
		</tr>
		<tr>
			<td>Cylindrical block</td>
			<td>Bel-Art Products</td>
			<td>09-718-1</td>
			<td>Replica plating</td>
		</tr>
	</tbody>
</table>

aseptic laboratory techniques: plating methods

<p class="jove_content">Microorganisms are present on all inanimate surfaces creating ubiquitous sources of possible contamination in the laboratory. Experimental success relies on the ability of a scientist to sterilize work surfaces and equipment as well as prevent contact of sterile instruments and solutions with non-sterile surfaces. Here we present the steps for several plating methods routinely used in the laboratory to isolate, propagate, or enumerate microorganisms such as bacteria and phage. All five methods incorporate aseptic technique, or procedures that maintain the sterility of experimental materials. Procedures described include (1) streak-plating bacterial cultures to isolate single colonies, (2) pour-plating and (3) spread-plating to enumerate viable bacterial colonies, (4) soft agar overlays to isolate phage and enumerate plaques, and (5) replica-plating to transfer cells from one plate to another in an identical spatial pattern. These procedures can be performed at the laboratory bench, provided they involve non-pathogenic strains of microorganisms (Biosafety Level 1, BSL-1). If working with BSL-2 organisms, then these manipulations must take place in a biosafety cabinet. Consult the most current edition of the <em>Biosafety in Microbiological and Biomedical Laboratories</em> (BMBL) as well as <em>Material Safety Data Sheets</em> (MSDS) for Infectious Substances to determine the biohazard classification as well as the safety precautions and containment facilities required for the microorganism in question. Bacterial strains and phage stocks can be obtained from research investigators, companies, and collections maintained by particular organizations such as the <em>American Type Culture Collection</em> (ATCC). It is recommended that non-pathogenic strains be used when learning the various plating methods. By following the procedures described in this protocol, students should be able to:<br />
<br />
&#9679; Perform plating procedures without contaminating media.<br />
&#9679; Isolate single bacterial colonies by the streak-plating method.<br />
&#9679; Use pour-plating and spread-plating methods to determine the concentration of bacteria.<br />
&#9679; Perform soft agar overlays when working with phage.<br />
&#9679; Transfer bacterial cells from one plate to another using the replica-plating procedure.<br />
&#9679; Given an experimental task, select the appropriate plating method.</p>

Watch this Scientific Journal Video about Aseptic Laboratory Techniques: Plating Methods at JoVE.com

Aseptic Laboratory Techniques: Plating Methods

<p class="jove_content">When working with media and reagents used to culture microorganisms, aseptic technique must be practiced to ensure contamination is minimized. A variety of plating methods are routinely used to isolate, propagate, or enumerate bacteria and phage, all of which incorporate procedures that maintain the sterility of experimental materials.</p>

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