Name: isolation and preparation of bacterial cell walls for compositional analysis by ultra performance liquid chromatography
Uploaded: 2014-01-15T13:45:00
Description: Watch this Scientific Journal Video about Isolation and Preparation of Bacterial Cell Walls for Compositional Analysis by Ultra Performance Liquid Chromatography at JoVE.com

This work was supported by NIH Director&#39;s New Innovator Award DP2OD006466 (to K.C.H.). The authors thank Russell Monds for a practical demonstration of the method and for scientific discussions.

1. Grow Bacterial Cultures in 2.5 ml of Media Overnight
Back-dilute cultures 1:100 into 250 ml of fresh media and grow to OD600 of 0.7-0.8. Prepare a solution of 6% sodium dodecyl sulfate (SDS) in water.
CAUTION: SDS powder is hazardous -&#160;avoid inhaling SDS powder; wear a mask over nose and mouth.
2. Day 1 -&#160;Lysing Bacterial Cultures is Performed over the Course of One Day and Overnight
<ol>
	<li>While diluted culture...

<ol>
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A critical step in this procedure is step 3.1 of the second day of sample preparation. If the SDS has precipitated overnight, or if the samples have been stored in 4% SDS for several weeks at room temperature, the samples must be reboiled for at least 1 hr to redissolve the SDS. A common cause for SDS precipitation is the use of media with potassium salts, so potassium should be avoided in media if possible. As mentioned in the Representative Results section, it is also critical to adjust the pH to within the isoelectric...

The goal of the method described herein is to isolate intact bacterial cell walls (sacculi) and to digest the peptidoglycan (PG) such that Ultra Performance Liquid Chromatography (UPLC) can be used to provide information such as the identity of the muropeptide components and their concentrations, the average length of glycan strands, and the fraction of material involved in crosslinks between strands. For a detailed discussion of PG biochemistry and muropeptide species, there are several excellent reviews that describe PG structure and its role in infection, resistance, morphogenesis, and growth1-6. High Performance Liquid Chromatography (HPLC) for PG analysis was initially developed by Glauner and Schwarz in the 1980s, and more recently has been enhanced and applied extensively in the labs of Miguel de Pedro and Waldemar Vollmer. Previous methods utilized amino acid analysis or paper chromatography, time-consuming and tedious techniques that do not yield accurate or complete assessments of cell-wall components.
UPLC analysis can be easily implemented in any basic research laboratory that has access to an ultracentrifuge and UPLC. The UPLC method that we present below isolates complete sacculi, thereby providing comprehensive, quantitative information on all chemical species therein. This method yields precise quantification of all muropeptides across a population of bacteria, all within a 20 min UPLC run. The implementation of this method involves only basic laboratory skills, without significant financial investment in materials. In order to execute the steps in this method, researchers need only be skilled in pipetting, preparing buffers and enzymes, and adjusting pH, making it accessible to a wide range of scientific disciplines. The choice of enzymes used in this protocol depends on the species of bacterium being analyzed; the protocol described here is useful for Escherichia coli, and has generally been found to be adequate for isolating sacculi from other Gram-negative organisms. Consultation with the literature is recommended when applying this method to Gram-positive bacteria; in these species, sacculus purification has traditionally been more difficult. In particular, this method may have to be altered in terms of enzyme choice and length of digestion times to accommodate the thicker walls and accessory polymers such as teichoic acids of Gram-positive bacteria. The first enzyme in this protocol cleaves outer membrane lipoprotein (such as Braun&#8217;s lipoprotein, or Lpp) attachment to the peptidoglycan, thereby releasing all but the C-terminal di- (or tri-) peptide of the Lpp from the cell wall. This step is necessary when examining Enterobacteria, but many other Gram-negative bacteria have no Lpp equivalents, and therefore this step can be skipped. A second enzyme specifically cleaves after the muramic acid component of the peptidoglycan, solubilizing the disaccharide subunit that forms the muropeptide species. To provide an accurate assessment of the architecture of the PG, care should be taken in digesting the sacculi to prevent cleavage of the crossbridges or any other part of the peptide stem.
Although the chemical compositions of peptidoglycan from over 100 strains of ~40 bacterial species have been analyzed by HPLC, no analyses have been performed with UPLC technology. In addition, previous work has characterized peptidoglycan from only a small fraction of the bacterial domain, in part limited by the throughput of HPLC. Therefore, dissemination of this method to as many researchers as possible, and implementation on UPLC platforms, will be critical for driving physiological studies of the large fraction of bacterial species whose peptidoglycan has yet to be categorized.

<table border="0" cellpadding="0" cellspacing="0" width="640">
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		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Pronase E</td>
			<td style="width:115px;">Amresco</td>
			<td style="width:119px;">E629</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mutanolysin from Streptomyces</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">M9901</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Sodium borohydride (NaBH4)&#160;</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">452882</td>
			<td>Sodium borohydride is highly reactive and dangerous to handle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Orthophosphoric acid&#160;</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">79607</td>
			<td>Orthophosphoric acid is corrosive and dangerous to handle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Boric acid</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">31146</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium azide</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">S2002</td>
			<td>Sodium azide is a poison</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium tetraborate</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">221732</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Millex 0.22 &#956;m syringe filters</td>
			<td style="width:115px;">Fisher</td>
			<td style="width:119px;">SLGVR04NL</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">pH strips (pH range 0-6)</td>
			<td style="width:115px;">Fisher</td>
			<td style="width:119px;">M95863</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">50 ml polypropylene Falcon tubes</td>
			<td style="width:115px;">VWR</td>
			<td style="width:119px;">21008-951</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">13 mm x 100 mm glass tubes</td>
			<td style="width:115px;">Kimble Chase</td>
			<td style="width:119px;">60CM13</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:240px;">12 mm x 32 mm screw neck glass recovery vial</td>
			<td style="width:115px;">Waters</td>
			<td style="width:119px;">186000327C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Sodium Dodecyl Sulfate</td>
			<td style="width:115px;">Ambion</td>
			<td style="width:119px;">AM9820</td>
			<td>SDS powder is hazardous</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;"></td>
			<td style="width:115px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Instrumentation</td>
			<td style="width:115px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="2" height="21" style="height:21px;">Waters Acquity UPLC H-Class system, including:</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="2" height="21" style="height:21px;">Acquity UPLC H-Class Sample Manager FTN</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="2" height="21" style="height:21px;">Acquity UPLC H-Class Quaternary Solvent Manager</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="2" height="21" style="height:21px;">Acquity UPLC BEH C18 1.7 &#181;m column</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acquity UPLC PDA Detector</td>
			<td style="width:115px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Waters Fraction Collector III</td>
			<td style="width:115px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="2" height="21" style="height:21px;">Acquity UPLC 30 cm Column Heater/Cooler</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation and preparation of bacterial cell walls for compositional analysis by ultra performance liquid chromatography

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the face of turgor pressures several atmospheres in magnitude. Across the diverse shapes and sizes of the bacterial kingdom, the cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by short peptides. Peptidoglycan&#8217;s central importance to bacterial physiology underlies its use as an antibiotic target and has motivated genetic, structural, and cell biological studies of how it is robustly assembled during growth and division. Nonetheless, extensive investigations are still required to fully characterize the key enzymatic activities in peptidoglycan synthesis and the chemical composition of bacterial cell walls. High Performance Liquid Chromatography (HPLC) is a powerful analytical method for quantifying differences in the chemical composition of the walls of bacteria grown under a variety of environmental and genetic conditions, but its throughput is often limited. Here, we present a straightforward procedure for the isolation and preparation of bacterial cell walls for biological analyses of peptidoglycan via HPLC and Ultra Performance Liquid Chromatography (UPLC), an extension of HPLC that utilizes pumps to deliver ultra-high pressures of up to 15,000 psi, compared with 6,000 psi for HPLC. In combination with the preparation of bacterial cell walls presented here, the low-volume sample injectors, detectors with high sampling rates, smaller sample volumes, and shorter run times of UPLC will enable high resolution and throughput for novel discoveries of peptidoglycan composition and fundamental bacterial cell biology in most biological laboratories with access to an ultracentrifuge and UPLC.

Using the procedure outlined in Figure&#160;1, the final sample should consist of at least 200 &#181;l&#160;of clear solution that has been filtered directly into a UPLC vial (step 4.4). UPLC separation of the various muropeptides in a bacterial sample relies upon their relative solubility between the liquid mobile phase and the column&#8217;s stationary phase. Reversed-phase C18 columns provide a strongly hydrophobic matrix to separate the muropeptide species based on hydrophobicity and size8...

Watch this Scientific Journal Video about Isolation and Preparation of Bacterial Cell Walls for Compositional Analysis by Ultra Performance Liquid Chromatography at JoVE.com

Isolation and Preparation of Bacterial Cell Walls for Compositional Analysis by Ultra Performance Liquid Chromatography

The bacterial cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by peptides. Ultra Performance Liquid Chromatography provides high resolution and throughput for novel discoveries of peptidoglycan composition. We present a procedure for the isolation of cell walls (sacculi) and their subsequent preparation for analysis via UPLC.

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the ...

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