Name: total protein extraction and 2-d gel electrophoresis methods for burkholderia species
Uploaded: 2013-10-15T17:30:00
Description: Watch this Scientific Journal Video about Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species at JoVE.com

This work was supported by a studentship from The University of British Columbia (to B.V.) and grants from Cystic Fibrosis Canada and Canadian Institutes 
of Health Research (to D.P.S.). We thank Jacqueline Chung for the initial preparation of protocols.

1. Culture Growth (Days 1+2)
<ol>
	<li>Grow a starter culture: 3 ml of Luria Bertani (LB) broth in a snap top 15 ml tube, at 37 &#176;C rotator overnight. Dilute overnight growth to an OD600 of 0.6. Add 1 ml of this dilution to 100 ml of LB broth in a 250 ml Erlenmeyer flask. Incubate at 37 &#176;C with shaking at 250 rpm for 16 hr into stationary phase (SP), to better approximate, in batch culture, infection conditions and to assure that bacterial virulence factors under the control of stationary phase sign...

<ol>
	<li>Drevinek, P., Mahenthiralingam, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Burkholderia+cenocepacia+in+cystic+fibrosis:+epidemiology+and+molecular+mechanisms+of+virulence.">Burkholderia cenocepacia in cystic fibrosis: epidemiology and molecular mechanisms of virulence.</a> Clin. Microbiol. Infect. 16, 821-830 (2010).</li><li>Suarez-Moreno, Z. R., 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=Common+Features+of+Environmental+and+Potentially+Beneficial+Plant-Associated+Burkholderia.">Common Features of Environmental and Potentially Beneficial Plant-Associated Burkholderia.</a> Microb. Ecol. , (2011).</li><li>Wiersinga, W. J., van der Poll, T., White, N. J., Day, N. P., Peacock, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melioidosis:+insights+into+the+pathogenicity+of+Burkholderia+pseudomallei.">Melioidosis: insights into the pathogenicity of Burkholderia pseudomallei.</a> Nat. Rev. Microbiol. 4, 272-282 (2006).</li><li>White, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melioidosis.">Melioidosis.</a> Lancet. 361, 1715-1722 (2003).</li><li>Mahenthiralingam, E., Urban, T. A., Goldberg, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+multifarious,+multireplicon+Burkholderia+cepacia+complex.">The multifarious, multireplicon Burkholderia cepacia complex.</a> Nat. Rev. Microbiol. 3, 144-156 (2005).</li><li>Speert, D. P., Henry, D., Vandamme, P., Corey, M., Mahenthiralingam, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiology+of+Burkholderia+cepacia+complex+in+patients+with+cystic+fibrosis.">Epidemiology of Burkholderia cepacia complex in patients with cystic fibrosis.</a> Canada. Emerg. Infect. Dis. 8, 181-187 (2002).</li><li>Dance, D. A., Wuthiekanun, V., Chaowagul, W., White, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+antimicrobial+susceptibility+of+Pseudomonas+pseudomallei.+Emergence+of+resistance+in+vitro+and+during+treatment.">The antimicrobial susceptibility of Pseudomonas pseudomallei. Emergence of resistance in vitro and during treatment.</a> J. Antimicrob. Chemother. 24, 295-309 (1989).</li><li>Thibault, F. M., Hernandez, E., Vidal, D. R., Girardet, M., Cavallo, J. 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W., 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=Evidence+for+transmission+of+Pseudomonas+cepacia+by+social+contact+in+cystic+fibrosis.">Evidence for transmission of Pseudomonas cepacia by social contact in cystic fibrosis.</a> Lancet. 342, 15-19 (1993).</li><li>Thongboonkerd, V., 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=Altered+proteome+in+Burkholderia+pseudomallei+rpoE+operon+knockout+mutant:+insights+into+mechanisms+of+rpoE+operon+in+stress+tolerance,+survival,+and+virulence.">Altered proteome in Burkholderia pseudomallei rpoE operon knockout mutant: insights into mechanisms of rpoE operon in stress tolerance, survival, and virulence.</a> J. Proteome. Res. 6, 1334-1341 (2007).</li><li>Park, K. H., Lipuma, J. J., Lubman, D. 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V., 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=The+identification+of+surface+proteins+of+Burkholderia+pseudomallei.">The identification of surface proteins of Burkholderia pseudomallei.</a> Vaccine. 25, 2664-2672 (2007).</li><li>Madeira, A., Santos, P. M., Coutinho, C. P., Pinto-de-Oliveira, A., Sa-Correia, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+proteomics+(2-D+DIGE)+reveals+molecular+strategies+employed+by+Burkholderia+cenocepacia+to+adapt+to+the+airways+of+cystic+fibrosis+patients+under+antimicrobial+therapy.">Quantitative proteomics (2-D DIGE) reveals molecular strategies employed by Burkholderia cenocepacia to adapt to the airways of cystic fibrosis patients under antimicrobial therapy.</a> Proteomics. 11, 1313-1328 (2011).</li><li>Zlosnik, J. E. A., Speert, D. 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Dis. 202, 770-781 (2010).</li><li>Riedel, K., Carranza, P., Gehrig, P., Potthast, F., Eberl, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+the+proteome+of+Burkholderia+cenocepacia+H111:+setting+up+a+2-DE+reference+map.">Towards the proteome of Burkholderia cenocepacia H111: setting up a 2-DE reference map.</a> Proteomics. 6, 207-216 (2006).</li><li>Weiss, W., Gorg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sample+solublization+buffers+for+two-dimensional+electrophoresis.">Sample solublization buffers for two-dimensional electrophoresis.</a> Methods Mol. Biol. 424, 35-42 (2008).</li><li>von der Haar, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimized+protein+extraction+for+quantitative+proteomics+of+yeasts.">Optimized protein extraction for quantitative proteomics of yeasts.</a> PLoS One. 2, e1078 (2007).</li><li>O'Farrell, P. H. <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+two-dimensional+electrophoresis+of+proteins.">High resolution two-dimensional electrophoresis of proteins.</a> J. Biol. Chem. 250, 4007-4021 (1975).</li><li>Gorg, A., Weiss, W., Dunn, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+two-dimensional+electrophoresis+technology+for+proteomics.">Current two-dimensional electrophoresis technology for proteomics.</a> Proteomics. 4, 3665-3685 (2004).</li><li>Gygi, S. P., Rist, B., Griffin, T. J., Eng, J., Aebersold, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteome+analysis+of+low-abundance+proteins+using+multidimensional+chromatography+and+isotope-coded+affinity+tags.">Proteome analysis of low-abundance proteins using multidimensional chromatography and isotope-coded affinity tags.</a> J. Proteome Res. 1, 47-54 (2002).</li><li>Ross, P. L., 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=Multiplexed+protein+quantitation+in+Saccharomyces+cerevisiae+using+amine-reactive+isobaric+tagging+reagents.">Multiplexed protein quantitation in Saccharomyces cerevisiae using amine-reactive isobaric tagging reagents.</a> Mol. Cell Proteomics. 3, 1154-1169 (2004).</li><li>Velapati&#241;o, B., Limmathurotsakul, D., Peacock, S. J., Speert, D. P. <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+differentially+expressed+proteins+from+Burkholderia+pseudomallei+isolated+during+primary+and+relapsing+melioidosis.">Identification of differentially expressed proteins from Burkholderia pseudomallei isolated during primary and relapsing melioidosis.</a> Microbes. Infect. 14, 335-340 (2012).</li><li>Chung, J. W., Speert, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+identification+and+characterization+of+bacterial+factors+associated+with+Burkholderia+cenocepacia+survival+in+a+murine+host.">Proteomic identification and characterization of bacterial factors associated with Burkholderia cenocepacia survival in a murine host.</a> Microbiology. 153, 206-214 (2007).</li><li>Rotz, L. D., Khan, A. S., Lillibridge, S. R., Ostroff, S. M., Hughes, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Public+health+assessment+of+potential+biological+terrorism+agents.">Public health assessment of potential biological terrorism agents.</a> Emerg. Infect. Dis. 8, 225-230 (2002).</li><li>Thon, J. N., 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=Comprehensive+proteomic+analysis+of+protein+changes+during+platelet+storage+requires+complementary+proteomic+approaches.">Comprehensive proteomic analysis of protein changes during platelet storage requires complementary proteomic approaches.</a> Transfusion. 48, 425-435 (2008).</li><li>Wu, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+New+and+Emerging+Proteomic+Techniques.">In New and Emerging Proteomic Techniques.</a> Methods Mol. Biol. 328, 71-95 (2006).</li><li>Lopez, M. 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A method for proteins preparation has been described that can extract the majority of Burkholderia proteins with good reproducibility. This is demonstrated by obtaining the same protein profile from two independent preparations performed in different days using the same bacterial culture grown in LB or YEM broth as shown in Figure 1. Extraction was efficient for bacteria grown in liquid media; however we have not tested this method for bacteria grown on plates. This method was also used for furt...

The genus Burkholderia comprises more than 62 species, Gram negative organisms isolated from a wide range of niches, and it is divided in two main clusters1,2. The first cluster includes human, animal and phytotrophic organisms, and most studies have focused on the pathogenic species of this group due to their clinical importance. The most pathogenic members are B. pseudomallei and B. mallei (which causes melioidosis and glanders respectively)3,4 and opportunistic pathogens (the 17 defined species of the Burkholderia cepacia complex, BCC)5, which cause disease in cystic fibrosis (CF) and chronic granulomatous disease (CGD)1. The second cluster, with more than 30 nonpathogenic species, includes bacteria associated with plants or with the environment, and are considered potentially beneficial to the host2.
Numerous complications emerge from bacterial infection with the pathogenic members of the Burkholderia genus, such as transmission of the pathogen between patients, spread of the disease and treatment failure because of the intrinsic or acquired resistance to antibiotics making hard to eradicate in most of the cases6-9. Therefore, gaining a clearer understanding of the basis for establishment of bacterial infection is vital to the treatment of diseases caused by these organisms. In order to gain insight into the establishment of infection, extensive investigations on the bacterial components associated with pathogenesis are needed. Studies focusing on the proteomic analysis of Burkholderia organisms using proteomic approaches described proteins that have been implicated in bacterial pathogenesis as well as changes in their proteome profiles10-16.
Protein extraction methods using sonication and freeze-thawed cycles in lysis buffer containing high concentration of urea, thiourea in combination with detergent and ampholytes has been applied in Burkholderia proteomic studies10-13. Although urea is quite efficient for protein denaturation, it can establish an equilibrium in aqueous solution with ammonium isocyanate, which can react with amino acid groups, thereby forming artifacts (carbamylation reaction)17. Therefore, it is recommended to include carrier ampholytes, which act as cyanate scavengers and avoid temperatures above 37 &#176;C17. Furthermore, to prevent any chemical interference of lysis buffer with protein quantification, the same lysis buffer can be used to generate the standard curve so that the samples and the standards have the same background10. Other methodologies involve the use of alkaline buffers and detergents with heat incubation periods17,18; however these conditions might induce changes in the proteome and some detergents are not compatible with proteomics application unless subsequent detergent removal steps are included17,18.
After adequate extraction and quantification, global protein expression of each individual protein can be studied using proteomic approaches such as two-dimensional (2-D) gel electrophoresis. This technique was first described by O&#39;Farell19 and consists in the separation of proteins according to their isoelectric point by isoelectric focusing in the first dimension, and then according to their molecular weight by acrylamide gel electrophoresis in the second dimension. Due to its resolution and sensitivity, this technique is a powerful tool for the analysis and detection of proteins from complex biological sources19,20. This separation technique is currently available in protein-centric approaches with the great advantage of resolving protein isoforms caused by post-transcriptional modifications or proteolytic processing. Quantitative changes can be detected by comparing the intensity of the corresponding spot after staining of the gel20. However, this technique is not suited for the identification of very large proteins, membrane proteins, extremely basic and acidic or hydrophobic proteins, and is a somewhat laborious and time-consuming technique20. New peptide-centric approaches (non gel-based) that are more robust and objective become available and can be used for quantitative comparison by differential stable isotope labeling methods such as cysteine labeling by isotope-coded affinity tagging (ICAT)21, and amino group labeling by isotope tagging for relative and absolute quantitation (iTRAQ)22. The use of a single proteomic technique might give insufficient information; therefore the use of two complementary proteomic approaches is necessary for most fully assessing changes in proteome. Nevertheless, 2-D gel electrophoresis is widely used and can be routinely applied for quantitative expression of several proteins in different organisms.
Here we describe a whole-cell protein extraction and 2-D gel electrophoresis procedures for Burkholderia species that were adapted and optimized from the GE Healthcare 2-D Electrophoresis Principles and methods Handbook 80-6429-60AC 2004 (<a href="http://www.amershambiosciences.com" target="_blank">www.amershambiosciences.com</a>). The protein extraction was carried out using a bead beater with glass beads in the presence of PBS containing 5 mM EDTA (ethylenediamine tetraacetic acid) and 1 mM PMSF (phenylmethylsulfonyl fluoride). This procedure allows quantification of proteins with minimal degradation and is amendable for proteomic approaches as previously reported15,23,24. 2-D gel electrophoresis was carried out using 24 cm long immobilized pH 4-7 gradient and proteins were separated according to their isoelectric point. Then proteins were separated according to their molecular weight by SDS-polyacrylamide gel. Additionally, we described a silver staining method for visualization of spot proteins, and a silver stain method that is compatible for mass spectrometry analysis. Together these procedures can allow the identification of important proteins from Burkholderia species that could be involved in pathogenesis.

<table border="1">
 <tbody>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>Reagents</td>
 </tr>
 <tr>
 <td>Phenylmethanesulfonyl fluoride (PMSF)</td>
 <td>Sigma</td>
 <td>P7626</td>
 <td>Toxic, corrosive</td>
 </tr>
 <tr>
 <td>Acetone</td>
 <td>Fisher</td>
 <td>A18-1</td>
 <td>Flammable</td>
 </tr>
 <tr>
 <td>PBS Buffer</td>
 <td>Bioscience</td>
 <td>R028</td>
 <td></td>
 </tr>
 <tr>
 <td>Ethylenediaminetetraacetic acid (EDTA)</td>
 <td>Fisher</td>
 <td>BP118-500 </td>
 <td>toxic</td>
 </tr>
 <tr>
 <td>Glass beads (0.1 mm)</td>
 <td>BioSpec Products</td>
 <td>11079101</td>
 <td></td>
 </tr>
 <tr>
 <td>Nalgene Oak Ridge Centrifuge tubes, polycarbonate (50 ml)</td>
 <td>VWR</td>
 <td>21009-342</td>
 <td></td>
 </tr>
 <tr>
 <td>MicroBCA protein extraction kit</td>
 <td>Pierce</td>
 <td>23235</td>
 <td></td>
 </tr>
 <tr>
 <td>Microcentrifuge Tubes 2.0 ml conical Screw cap Tubes with Cap and O-Ring</td>
 <td>Fisher</td>
 <td>02-681-375</td>
 <td></td>
 </tr>
 <tr>
 <td>2-D Clean-Up kit</td>
 <td>GE Healthcare</td>
 <td>80-6484-51</td>
 <td></td>
 </tr>
 <tr>
 <td>Urea</td>
 <td>Invitrogen</td>
 <td>15505-050</td>
 <td>Irritant</td>
 </tr>
 <tr>
 <td>CHAPS</td>
 <td>Amersham Biosciences</td>
 <td>17-1314-01</td>
 <td></td>
 </tr>
 <tr>
 <td>Dithiothreitol (DTT)</td>
 <td>MPBiomedical, LCC</td>
 <td>856126</td>
 <td>Irritant</td>
 </tr>
 <tr>
 <td>Immobiline DryStrips pH 4-7 24 cm</td>
 <td>Amersham Biosciences</td>
 <td>176002-46</td>
 <td></td>
 </tr>
 <tr>
 <td>Duracryl</td>
 <td>Proteomic Solutions</td>
 <td>80-0148</td>
 <td>Very toxic, carcinogen</td>
 </tr>
 <tr>
 <td>Ammonium persulfate</td>
 <td>Fisher</td>
 <td>BP179-100</td>
 <td>Flammable, toxic, corrosive</td>
 </tr>
 <tr>
 <td>N,N,N',N'-tetramethylethylenediamine (TEMED)</td>
 <td>Invitrogen</td>
 <td>15524-010</td>
 <td>Flammable</td>
 </tr>
 <tr>
 <td>Sodium dodecyl sulfate (SDS)</td>
 <td>Fisher</td>
 <td>BP166-500</td>
 <td>Acute toxicity, flammable</td>
 </tr>
 <tr>
 <td>Agarose</td>
 <td>Invitrogen</td>
 <td>15510-027</td>
 <td></td>
 </tr>
 <tr>
 <td>Ethanol</td>
 <td>Fisher</td>
 <td>HC1100-1GL</td>
 <td>Flammable, toxic</td>
 </tr>
 <tr>
 <td>Acetic acid</td>
 <td>Fisher</td>
 <td>A491-212</td>
 <td>Flammable, corrosive</td>
 </tr>
 <tr>
 <td>Glutaraldehyde</td>
 <td>Fisher</td>
 <td>G151-1</td>
 <td>Very toxic, corrosive, dangerous for the environment</td>
 </tr>
 <tr>
 <td>Potassium tetrathionate</td>
 <td>Sigma</td>
 <td>P2926</td>
 <td>Irritant</td>
 </tr>
 <tr>
 <td>Sodium acetate</td>
 <td>EM Science</td>
 <td>7510</td>
 <td></td>
 </tr>
 <tr>
 <td>Silver nitrate</td>
 <td>Sigma</td>
 <td>209139</td>
 <td>Corrosive, dangerous for the environment</td>
 </tr>
 <tr>
 <td>Formaldehyde</td>
 <td>Sigma</td>
 <td>252549</td>
 <td>Toxic</td>
 </tr>
 <tr>
 <td>Sodium thiosulfate</td>
 <td>Sigma</td>
 <td>S7026</td>
 <td></td>
 </tr>
 <tr>
 <td>Tris Base</td>
 <td>EMD</td>
 <td>9230</td>
 <td></td>
 </tr>
 <tr>
 <td>Glycine</td>
 <td>MPBiomedical, LCC</td>
 <td>808831</td>
 <td></td>
 </tr>
 <tr>
 <td>Glycerol</td>
 <td>MPBiomedical, LCC</td>
 <td>800688</td>
 <td></td>
 </tr>
 <tr>
 <td>Methanol</td>
 <td>Fisher</td>
 <td>A412-4</td>
 <td>Flammable, toxic, health hazard</td>
 </tr>
 <tr>
 <td>Sodium carbonate anhydrous</td>
 <td>EMD</td>
 <td>SX0400-3</td>
 <td>Toxic</td>
 </tr>
 <tr>
 <td>Mineral oil</td>
 <td>ACROS</td>
 <td>415080010</td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>Equipment </td>
 </tr>
 <tr>
 <td>JA-20 ultracentrifuge rotor</td>
 <td>Beckman Coulter</td>
 <td>334831</td>
 <td></td>
 </tr>
 <tr>
 <td>Mini Beadbeater</td>
 <td>Biospec Products</td>
 <td>3110BX</td>
 <td></td>
 </tr>
 <tr>
 <td>Ettan IPGphor II Isoelectric Focusing System and accessories</td>
 <td>GE Healthcare</td>
 <td>80-6505-03</td>
 <td><a href="http://www.amershambiosciences.com" target="_blank">www.amershambiosciences.com</a></td>
 </tr>
 <tr>
 <td>Ettan DALT Large Vertical electrophoresis system</td>
 <td>GE Healthcare</td>
 <td>80-6485-27</td>
 <td><a href="http://www.amershambiosciences.com" target="_blank">www.amershambiosciences.com</a></td>
 </tr>
 </tbody>
</table>

total protein extraction and 2-d gel electrophoresis methods for burkholderia species

The investigation of the intracellular protein levels of bacterial species is of importance to understanding the pathogenic mechanisms of diseases caused by these organisms. Here we describe a procedure for protein extraction from Burkholderia species based on mechanical lysis using glass beads in the presence of ethylenediamine tetraacetic acid and phenylmethylsulfonyl fluoride in phosphate buffered saline. This method can be used for different Burkholderia species, for different growth conditions, and it is likely suitable for the use in proteomic studies of other bacteria. Following protein extraction, a two-dimensional (2-D) gel electrophoresis proteomic technique is described to study global changes in the proteomes of these organisms. This method consists of the separation of proteins according to their isoelectric point by isoelectric focusing in the first dimension, followed by separation on the basis of molecular weight by acrylamide gel electrophoresis in the second dimension. Visualization of separated proteins is carried out by silver staining.

Comparative analysis of the protein profiles extracted from the same bacterial culture on two different occasions showed similar patterns banding indicating successful protein extractions. Molecular weight proteins extracted ranged from 10-150 kDa. Figure 1 shows representative Coomassie blue staining gel of the whole-cell protein extractions from Burkholderia multivorans (a member of the BCC) clinical isolates grown in LB or Yeast/Manitol (YEM) broth and harvested from stationary phase.
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Watch this Scientific Journal Video about Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species at JoVE.com

Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species

Members of the Burkholderia genus are pathogens of clinical importance. We describe a method for total bacterial protein extraction, using mechanical disruption, and 2-D gel electrophoresis for subsequent proteomic analysis.

Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species

The investigation of  the intracellular protein levels of bacterial species is of importance to  understanding the pathogenic mechanisms of diseases ...

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Research

JoVE Journal

Immunology and Infection

A 1.5 Hour Procedure for Identification of Enterococcus Species Directly from Blood Cultures

Enterococci are a common cause of bacteremia with E. faecalis being the predominant species followed by E. faecium. Because resistance to ampicillin and vancomycin in E. faecalis is still uncommon compared to resistance in E. faecium, the development of rapid tests allowing differentiation between enterococcal species is important for appropriate therapy and resistance surveillance. The E. faecalis OE PNA FISH assay (AdvanDx, Woburn, MA) uses species-specific peptide nucleic acid (PNA) probes in a fluorescence in situ hybridization format and offers a time to results of 1.5 hours and the potential of providing important information for species-specific treatment. Multicenter studies were performed to assess the performance of the 1.5 hour E. faecalis/OE PNA FISH procedure compared to the original 2.5 hour assay procedure and to standard bacteriology methods for the identification of enterococci directly from a positive blood culture bottle.

A 1.5 Hour Procedure for Identification of Enterococcus Species Directly from Blood Cultures

A rapid protocol for the direct identification of Enterococcus faecalis and other Enterococcus species from a positive blood culture using a Peptide Nucleic Acid fluorescent in situ hybridization assay (PNA FISH).

Enterococci are a common cause of bacteremia with E. faecalis being the predominant species followed by E. faecium.  Because resistance to ampicillin and ...

Avian Influenza Surveillance with FTA  Cards: Field Methods, Biosafety, and Transportation Issues Solved

Avian Influenza Viruses (AIVs) infect many mammals, including humans1. These AIVs are diverse in their natural hosts, harboring almost all possible viral subtypes2. Human pandemics of flu originally stem from AIVs3. Many fatal human cases during the H5N1 outbreaks in recent years were reported. Lately, a new AIV related strain swept through the human population, causing the 'swine flu epidemic'4. Although human trading and transportation activity seems to be responsible for the spread of highly pathogenic strains5, dispersal can also partly be attributed to wild birds6, 7. However, the actual reservoir of all AIV strains is wild birds.
In reaction to this and in face of severe commercial losses in the poultry industry, large surveillance programs have been implemented globally to collect information on the ecology of AIVs, and to install early warning systems to detect certain highly pathogenic strains8-12. Traditional virological methods require viruses to be intact and cultivated before analysis. This necessitates strict cold chains with deep freezers and heavy biosafety procedures to be in place during transport. Long-term surveillance is therefore usually restricted to a few field stations close to well equipped laboratories. Remote areas cannot be sampled unless logistically cumbersome procedures are implemented. These problems have been recognised13, 14 and the use of alternative storage and transport strategies investigated (alcohols or guanidine)15-17. Recently, Kraus et al.18 introduced a method to collect, store and transport AIV samples, based on a special filter paper. FTA cards19 preserve RNA on a dry storage basis20 and render pathogens inactive upon contact21. This study showed that FTA cards can be used to detect AIV RNA in reverse-transcription PCR and that the resulting cDNA could be sequenced and virus genes and determined.
In the study of Kraus et al.18 a laboratory isolate of AIV was used, and samples were handled individually. In the extension presented here, faecal samples from wild birds from the duck trap at the Ottenby Bird Observatory (SE Sweden) were tested directly to illustrate the usefulness of the methods under field conditions. Catching of ducks and sample collection by cloacal swabs is demonstrated. The current protocol includes up-scaling of the work flow from single tube handling to a 96-well design. Although less sensitive than the traditional methods, the method of FTA cards provides an excellent supplement to large surveillance schemes. It allows collection and analysis of samples from anywhere in the world, without the need to maintaining a cool chain or safety regulations with respect to shipping of hazardous reagents, such as alcohol or guanidine.

A method to preserve, detect and sequence RNA from Avian Influenza Viruses was validated and extended using natural faecal samples from birds. This technique removes the necessity of maintaining a cool chain and handling of infectious viruses and can be applied in a 96-well high-throughput setup.

Avian Influenza Viruses (AIVs) infect many mammals, including humans1. These AIVs are diverse in their natural hosts, harboring almost all possible viral ...

A Simple Chelex Protocol for DNA Extraction from Anopheles spp.

Endemic countries are increasingly adopting molecular tools for efficient typing, identification and surveillance against malaria parasites and vector mosquitoes, as an integral part of their control programs1,2,3,4,5. For sustainable establishment of these accurate approaches in operations research to strengthen malaria control and elimination efforts, simple and affordable methods, with parsimonious reagent and equipment requirements are essential6,7,8. Here we present a simple Chelex-based technique for extracting malaria parasite and vector DNA from field collected mosquito specimens.
We morphologically identified 72 Anopheles gambiae sl. from 156 mosquitoes captured by pyrethrum spray catches in sleeping rooms of households within a 2,000 km2 vicinity of the Malaria Institute at Macha. After dissection to separate the head and thorax from the abdomen for all 72 Anopheles gambiae sl. mosquitoes, the two sections were individually placed in 1.5 ml microcentrifuge tubes and submerged in 20 &mu;l of deionized water. Using a sterile pipette tip, each mosquito section was separately homogenized to a uniform suspension in the deionized water. Of the ensuing homogenate from each mosquito section, 10 &mu;l was retained while the other 10 &mu;l was transferred to a separate autoclaved 1.5 ml tube. The separate aliquots were subjected to DNA extraction by either the simplified Chelex or the standard salting out extraction protocol9,10. The salting out protocol is so-called and widely used because it employs high salt concentrations in lieu of hazardous organic solvents (such as phenol and chloroform) for the protein precipitation step during DNA extraction9.
Extracts were used as templates for PCR amplification using primers targeting arthropod mitochondrial nicotinamide adenine dinucleotide dehydrogenase (NADH) subunit 4 gene (ND4) to check DNA quality11, a PCR for identification of Anopheles gambiae sibling species10 and a nested PCR for typing of Plasmodium falciparum infection12. Comparison using DNA quality (ND4) PCR showed 93% sensitivity and 82% specificity for the Chelex approach relative to the established salting out protocol. Corresponding values of sensitivity and specificity were 100% and 78%, respectively, using sibling species identification PCR and 92% and 80%, respectively for P. falciparum detection PCR. There were no significant differences in proportion of samples giving amplicon signal with the Chelex or the regular salting out protocol across all three PCR applications. The Chelex approach required three simple reagents and 37 min to complete, while the salting out protocol entailed 10 different reagents and 2 hr and 47 min' processing time, including an overnight step. Our results show that the Chelex method is comparable to the existing salting out extraction and can be substituted as a simple and sustainable approach in resource-limited settings where a constant reagent supply chain is often difficult to maintain.

A Simple Chelex Protocol for DNA Extraction from Anopheles spp.

A rapid and affordable way to extract quality malaria parasite and vector DNA from mosquito specimens is described. Capitalizing on chelating properties of Chelex resin, the simple method enables genotyping of malaria parasites in mosquito mid-gut and salivary gland phases, as well as molecular identification of the Anopheles sibling species by PCR.

Endemic countries are increasingly adopting molecular tools for  efficient typing, identification and surveillance against malaria parasites and  vector ...

Procedures for Identifying Infectious Prions After Passage Through the Digestive System of an Avian Species

Infectious prion (PrPRes) material is likely the cause of fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) diseases1. Transmission of TSE diseases, such as chronic wasting disease (CWD), is presumed to be from animal to animal2,3 as well as from environmental sources4-6. Scavengers and carnivores have potential to translocate PrPRes material through consumption and excretion of CWD-contaminated carrion. Recent work has documented passage of PrPRes material through the digestive system of American crows (Corvus brachyrhynchos), a common North American scavenger7.
We describe procedures used to document passage of PrPRes material through American crows. Crows were gavaged with RML-strain mouse-adapted scrapie and their feces were collected 4 hr post gavage. Crow feces were then pooled and injected intraperitoneally into C57BL/6 mice. Mice were monitored daily until they expressed clinical signs of mouse scrapie and were thereafter euthanized. Asymptomatic mice were monitored until 365 days post inoculation. Western blot analysis was conducted to confirm disease status. Results revealed that prions remain infectious after traveling through the digestive system of crows and are present in the feces, causing disease in test mice.

Scavengers have potential to translocate infectious transmissible spongiform encephalopathy prions in their feces to disease-free areas. We detail methods used to determine if mouse-adapted scrapie prions remain infectious after passage though the digestive tract of American crows (Corvus brachyrhynchos), a common consumer of dead animals.

Infectious prion (PrPRes) material is likely the cause of fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) diseases1. Transmission ...

Establishment and Optimization of a High Throughput Setup to Study Staphylococcus epidermidis and Mycobacterium marinum Infection as a Model for Drug Discovery

Zebrafish are becoming a valuable tool in the preclinical phase of drug discovery screenings as a whole animal model with high throughput screening possibilities. They can be used to bridge the gap between cell based assays at earlier stages and in vivo validation in mammalian models, reducing, in this way, the number of compounds passing through to testing on the much more expensive rodent models. In this light, in the present manuscript is described a new high throughput pipeline using zebrafish as in vivo model system for the study of Staphylococcus epidermidis and Mycobacterium marinum infection. This setup allows the generation and analysis of large number of synchronous embryos homogenously infected. Moreover the flexibility of the pipeline allows the user to easily implement other platforms to improve the resolution of the analysis when needed. The combination of the zebrafish together with innovative high throughput technologies opens the field of drug testing and discovery to new possibilities not only because of the strength of using a whole animal model but also because of the large number of transgenic lines available that can be used to decipher the mode of action of new compounds.

Establishment and Optimization of a High Throughput Setup to Study Staphylococcus epidermidis and Mycobacterium marinum Infection as a Model for Drug Discovery

This video article describes the high throughput pipeline that has been successfully established to infect and analyze large numbers of zebrafish embryos providing a new powerful tool for compound testing and drug discovery using a whole animal vertebrate organism.

Zebrafish are becoming a valuable tool in the preclinical phase of drug discovery screenings as a whole animal model with high throughput screening ...

Proteomic Profiling of Macrophages by 2D Electrophoresis

The goal of the two-dimensional (2D) electrophoresis protocol described here is to show how to analyse the phenotype of human cultured macrophages. The key role of macrophages has been shown in various pathological disorders such as inflammatory, immunological, and infectious diseases. In this protocol, we use primary cultures of human monocyte-derived macrophages that can be differentiated into the M1 (pro-inflammatory) or the M2 (anti-inflammatory) phenotype. This in vitro model is reliable for studying the biological activities of M1 and M2 macrophages and also for a proteomic approach. Proteomic techniques are useful for comparing the phenotype and behaviour of M1 and M2 macrophages during host pathogenicity. 2D gel electrophoresis is a powerful proteomic technique for mapping large numbers of proteins or polypeptides simultaneously. We describe the protocol of 2D electrophoresis using fluorescent dyes, named 2D Differential Gel Electrophoresis (DIGE). The M1 and M2 macrophages proteins are labelled with cyanine dyes before separation by isoelectric focusing, according to their isoelectric point in the first dimension, and their molecular mass, in the second dimension. Separated protein or polypeptidic spots are then used to detect differences in protein or polypeptide expression levels. The proteomic approaches described here allows the investigation of the macrophage protein changes associated with various disorders like host pathogenicity or microbial toxins.

Macrophages are the key cells involved in host pathogenicity. Macrophages display phenotypic and functional diversity that can be analysed and detected by proteomic analysis. This article describes how to perform 2D electrophoresis of primary cultures of human macrophages differentiated into M1 or M2 phenotype.

The goal of the two-dimensional (2D) electrophoresis protocol described here is to show how to analyse the phenotype of human cultured macrophages. The ...

Loop-mediated Isothermal Amplification (LAMP) Assays for the Species-specific Detection of Eimeria that Infect Chickens

Eimeria species parasites, protozoa which cause the enteric disease coccidiosis, pose a serious threat to the production and welfare of chickens. In the absence of effective control clinical coccidiosis can be devastating. Resistance to the chemoprophylactics frequently used to control Eimeria is common and sub-clinical infection is widespread, influencing feed conversion ratios and susceptibility to other pathogens such as Clostridium perfringens. Despite the availability of polymerase chain reaction (PCR)-based tools, diagnosis of Eimeria infection still relies almost entirely on traditional approaches such as lesion scoring and oocyst morphology, but neither is straightforward. Limitations of the existing molecular tools include the requirement for specialist equipment and difficulties accessing DNA as template. In response a simple field DNA preparation protocol and a panel of species-specific loop-mediated isothermal amplification (LAMP) assays have been developed for the seven Eimeria recognised to infect the chicken. We now provide a detailed protocol describing the preparation of genomic DNA from intestinal tissue collected post-mortem, followed by setup and readout of the LAMP assays. Eimeria species-specific LAMP can be used to monitor parasite occurrence, assessing the efficacy of a farm&#8217;s anticoccidial strategy, and to diagnose sub-clinical infection or clinical disease with particular value when expert surveillance is unavailable.

Loop-mediated Isothermal Amplification LAMP Assays for the Species-specific Detection of Eimeria that Infect Chickens

Diagnosis of Eimeria infection in chickens remains demanding. Parasite morphology- and host pathology-led approaches are commonly inconclusive, while molecular approaches based on PCR have proven demanding in cost and expertise. The aim of this protocol is to establish loop-mediated isothermal amplification (LAMP) as a straightforward molecular diagnostic for eimerian infection.

Eimeria species parasites, protozoa which cause the enteric disease coccidiosis, pose a serious threat to the production and welfare of chickens. In the ...

Alternative In Vitro Methods for the Determination of Viral Capsid Structural Integrity

Human norovirus exacts considerable public health and economic losses worldwide. Emerging in vitro cultivation advances are not yet applicable for routine detection of the virus. The current detection and quantification techniques, which rely primarily on nucleic acid amplification, do not discriminate infectious from non-infectious viral particles. The purpose of this article is to present specific details on recent advances in techniques used together in order to acquire further information on the infectivity status of viral particles. One technique involves assessing binding of a norovirus ssDNA aptamer to capsids. Aptamers have the advantage of being easily synthesized and modified, and are inexpensive and stable. Another technique, dynamic light scattering (DLS), has the advantage of observing capsid behavior in solution. Electron microscopy allows for visualization of the structural integrity of the viral capsids. Although promising, there are some drawbacks to each technique, such as non-specific aptamer binding to positively-charged molecules from sample matrices, requirement of purified capsid for DLS, and poor sensitivity for electron microscopy. Nonetheless, when these techniques are used in combination, the body of data produced provides more comprehensive information on norovirus capsid integrity that can be used to infer infectivity, information which is essential for accurate evaluation of inactivation methods or interpretation of virus detection. This article provides protocols for using these methods to discriminate infectious human norovirus particles.

Alternative In Vitro Methods for the Determination of Viral Capsid Structural Integrity

Routine detection methods utilizing viral genome amplification are limited by their inability to discriminate infectious from non-infectious particles. The purpose of this article is to provide detailed protocols for alternative methods to aid in discrimination of infectious norovirus particles using aptamer binding, dynamic light scattering, and transmission electron microscopy.

Human norovirus exacts considerable public health and economic losses worldwide. Emerging in vitro cultivation advances are not yet applicable for routine ...

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification (BiCAP)

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research is deciphering how these dynamic protein complexes act to integrate signals from multiple sources in order to direct a specific biological response, and how this becomes deregulated in many disease settings. Despite the importance of this key biochemical mechanism, there is a lack of experimental techniques that can facilitate the specific and sensitive deconvolution of these multi-molecular signaling complexes.
Here this shortcoming is addressed through the combination of a protein complementation assay with a conformation-specific nanobody, which we have termed Bimolecular Complementation Affinity Purification (BiCAP). This novel technique facilitates the specific isolation and downstream proteomic characterization of any pair of interacting proteins, to the exclusion of un-complexed individual proteins and complexes formed with competing binding partners. 
The BiCAP technique is adaptable to a wide array of downstream experimental assays, and the high degree of specificity afforded by this technique allows more nuanced investigations into the mechanics of protein complex assembly than is currently possible using standard affinity purification techniques.

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification BiCAP

This manuscript describes the protocol for Bimolecular Complementation Affinity Purification (BiCAP). This novel method facilitates the specific isolation and downstream proteomic characterization of any two interacting proteins, while excluding un-complexed individual proteins as well as complexes formed with competing binding partners.

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research ...

Native Polyacrylamide Gel Electrophoresis Immunoblot Analysis of Endogenous IRF5 Dimerization

Interferon regulatory factor 5 (IRF5) is a key transcription factor for regulating the immune response. It is activated downstream of the Toll-like receptor myeloid differentiation primary response gene 88 (TLR-MyD88) signaling pathway. IRF5 activation involves phosphorylation, dimerization, and subsequent translocation from the cytoplasm into the nucleus, which in turn induces the gene expression of various pro-inflammatory cytokines. A detection assay for IRF5 activation is essential to studying IRF5 functions and its relevant pathways. This article describes a robust assay to detect endogenous IRF5 activation in the CAL-1 human plasmacytoid dendritic cell (pDC) line. The protocol consists of a modified nondenaturing electrophoresis assay that can distinguish IRF5 in its monomer and dimer forms, thus providing an affordable and sensitive approach to analyze IRF5 activation.

A native Western blot method for analyzing endogenous interferon regulatory factor 5 dimerization in the CAL-1 plasmacytoid dendritic cell line is described. This protocol can be applied to other cell lines as well.

Interferon regulatory factor 5 (IRF5) is a key transcription factor for regulating the immune response. It is activated downstream of the Toll-like ...