This research was funded by the Spanish Ministry of Science, Innovation and Universities (RTI2018-098777-B-I00), the FEDER Funds, and the Generalitat of Catalunya (2017SGR-229). Sandra Guallar-Garrido is the recipient of a PhD contract (FI) from the Generalitat de Catalunya.

1. Extraction of the total non-covalent-linked lipids from mycobacteria (Figure 1)
<ol>
	<li>Scratch 0.2 g of mycobacteria from a solid media and add to a glass tube with a polytetrafluoroethlene (PTFE) liner screw caps. Add a solution consisting of 5 mL of chloroform and 10 mL of methanol (chloroform:methanol, 1:2). 
	NOTE: When organic solvents are used, only glass recipient should be used. No plastic containers are allowed. Moreover, PTFE liner screw caps for bottles are needed.<br...

<ol>
	<li>Watanabe, M., 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=Location+of+functional+groups+in+mycobacterial+meromycolate+chains;+the+recognition+of+new+structural+principles+in+mycolic+acids.">Location of functional groups in mycobacterial meromycolate chains; the recognition of new structural principles in mycolic acids.</a> Microbiology. 148 (6), 1881-1902 (2002).</li><li>Global Health Organization World Health Organization. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=(2018)+Global+tuberculosis+report.">(2018) Global tuberculosis report.</a> WHO. , (2019).</li><li>Jackson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Mycobacterial+cell+envelope-lipids.">The Mycobacterial cell envelope-lipids.</a> Cold Spring Harbor Perspectives in Medicine. 4 (10), 1-36 (2014).</li><li>Jankute, M., 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+role+of+hydrophobicity+in+tuberculosis+evolution+and+pathogenicity.">The role of hydrophobicity in tuberculosis evolution and pathogenicity.</a> Scientific Reports. 7 (1), 1315 (2017).</li><li>Reed, M. B., Gagneux, S., DeRiemer, K., Small, P. M., Barry, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+W-Beijing+lineage+of+Mycobacterium+tuberculosis+overproduces+triglycerides+and+has+the+DosR+dormancy+regulon+constitutively+upregulated.">The W-Beijing lineage of Mycobacterium tuberculosis overproduces triglycerides and has the DosR dormancy regulon constitutively upregulated.</a> Journal of Bacteriology. 189 (7), 2583-2589 (2007).</li><li>Ly, A., Liu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mycobacterial+virulence+factors:+Surface-exposed+lipids+and+secreted+proteins.">Mycobacterial virulence factors: Surface-exposed lipids and secreted proteins.</a> International Journal of Molecular Sciences. 21 (11), 3985 (2020).</li><li>Szulc-Kielbik, I., 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=Severe+inhibition+of+lipooligosaccharide+synthesis+induces+TLR2-dependent+elimination+of+Mycobacterium+marinum+from+THP1-derived+macrophages.">Severe inhibition of lipooligosaccharide synthesis induces TLR2-dependent elimination of Mycobacterium marinum from THP1-derived macrophages.</a> Microbial Cell Factories. 16 (1), 217 (2017).</li><li>Ren, H., 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=Identification+of+the+lipooligosaccharide+biosynthetic+gene+cluster+from+Mycobacterium+marinum.">Identification of the lipooligosaccharide biosynthetic gene cluster from Mycobacterium marinum.</a> Molecular Microbiology. 63 (5), 1345-1359 (2007).</li><li>Roux, A. 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=The+distinct+fate+of+smooth+and+rough+Mycobacterium+abscessus+variants+inside+macrophages.">The distinct fate of smooth and rough Mycobacterium abscessus variants inside macrophages.</a> Open Biology. 6 (11), 160185 (2016).</li><li>Guallar-Garrido, S., Juli&#225;n, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacillus+Calmette-Gu&#233;rin+(BCG)+therapy+for+bladder+cancer:+An+update.">Bacillus Calmette-Gu&#233;rin (BCG) therapy for bladder cancer: An update.</a> ImmunoTargets and Therapy. 9, 1-11 (2020).</li><li>Bach-Griera, M., 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=Mycolicibacterium+brumae+is+a+safe+and+non-toxic+immunomodulatory+agent+for+cancer+treatment.">Mycolicibacterium brumae is a safe and non-toxic immunomodulatory agent for cancer treatment.</a> Vaccines. 8 (2), 2-17 (2020).</li><li>Noguera-Ortega, E., 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=Nonpathogenic+Mycobacterium+brumae+inhibits+bladder+cancer+growth+in+vitro,+ex+vivo,+and+in+vivo.">Nonpathogenic Mycobacterium brumae inhibits bladder cancer growth in vitro, ex vivo, and in vivo.</a> European Urology Focus. 2 (1), 67-76 (2015).</li><li>Noguera-Ortega, E., 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=Mycobacteria+emulsified+in+olive+oil-in-water+trigger+a+robust+immune+response+in+bladder+cancer+treatment.">Mycobacteria emulsified in olive oil-in-water trigger a robust immune response in bladder cancer treatment.</a> Scientific Reports. 6, 27232 (2016).</li><li>Rodr&#237;guez-G&#252;ell, E., 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+production+of+a+new+extracellular+putative+long-chain+saturated+polyester+by+smooth+variants+of+Mycobacterium+vaccae+interferes+with+Th1-cytokine+production.">The production of a new extracellular putative long-chain saturated polyester by smooth variants of Mycobacterium vaccae interferes with Th1-cytokine production.</a> Antonie van Leeuwenhoek. 90, 93-108 (2006).</li><li>Garcia-Vilanova, A., Chan, J., Torrelles, 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=Underestimated+manipulative+roles+of+Mycobacterium+tuberculosis+cell+envelope+glycolipids+during+infection.">Underestimated manipulative roles of Mycobacterium tuberculosis cell envelope glycolipids during infection.</a> Frontiers in Immunology. 10, (2019).</li><li>Yang, 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=Changes+in+the+major+cell+envelope+components+of+Mycobacterium+tuberculosis+during+in+vitro+growth.">Changes in the major cell envelope components of Mycobacterium tuberculosis during in vitro growth.</a> Glycobiology. 23 (8), 926-934 (2013).</li><li>Guallar-Garrido, S., Campo-P&#233;rez, V., S&#225;nchez-Chardi, A., Luquin, M., Juli&#225;n, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Each+mycobacterium+requires+a+specific+culture+medium+composition+for+triggering+an+optimized+immunomodulatory+and+antitumoral+effect.">Each mycobacterium requires a specific culture medium composition for triggering an optimized immunomodulatory and antitumoral effect.</a> Microorganisms. 8 (5), 734 (2020).</li><li>Venkataswamy, M. M., 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=et+al.+In+vitro+culture+medium+influences+the+vaccine+efficacy+of+Mycobacterium+bovis+BCG.">et al. In vitro culture medium influences the vaccine efficacy of Mycobacterium bovis BCG.</a> Vaccine. 30 (6), 1038-1049 (2012).</li><li>Secanella-Fandos, S., Luquin, M., P&#233;rez-Trujillo, M., Juli&#225;n, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Revisited+mycolic+acid+pattern+of+Mycobacterium+confluentis+using+thin-layer+chromatography.">Revisited mycolic acid pattern of Mycobacterium confluentis using thin-layer chromatography.</a> Journal of Chromatography B. 879, 2821-2826 (2011).</li><li>Minnikin, D. E., 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=Analysis+of+mycobacteria+mycolic+acids.">Analysis of mycobacteria mycolic acids.</a> Topics in Lipid Research: From Structural Elucidation to Biological Function. , 139-143 (1986).</li><li>Minnikin, D. E., Hutchinson, I. G., Caldicott, A. B., Goodfellow, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thin-layer+chromatography+of+methanolysates+of+mycolic+acid-containing+bacteria.">Thin-layer chromatography of methanolysates of mycolic acid-containing bacteria.</a> Journal of Chromatography A. 188 (1), 221-233 (1980).</li><li>Minnikin, D. E., Goodfellow, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+composition+in+the+classification+and+identification+of+acid-fast+bacteria.">Lipid composition in the classification and identification of acid-fast bacteria.</a> Society for Applied Bacteriology Symposium Series. 8, 189-256 (1980).</li><li>Mu&#241;oz, M., 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=Occurrence+of+an+antigenic+triacyl+trehalose+in+clinical+isolates+and+reference+strains+of+Mycobacterium+tuberculosis.">Occurrence of an antigenic triacyl trehalose in clinical isolates and reference strains of Mycobacterium tuberculosis.</a> FEMS Microbiology Letters. 157 (2), 251-259 (1997).</li><li>Daff&#233;, M., Lacave, C., Lan&#233;elle, M. A., Gillois, M., Lan&#233;elle, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polyphthienoyl+trehalose,+glycolipids+specific+for+virulent+strains+of+the+tubercle+bacillus.">Polyphthienoyl trehalose, glycolipids specific for virulent strains of the tubercle bacillus.</a> European Journal of Biochemistry. 172 (3), 579-584 (1988).</li><li>Singh, P., 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=Revisiting+a+protocol+for+extraction+of+mycobacterial+lipids.">Revisiting a protocol for extraction of mycobacterial lipids.</a> International Journal of Mycobacteriology. 3 (3), 168-172 (2014).</li><li>Camacho, L. 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=Analysis+of+the+phthiocerol+dimycocerosate+locus+of+Mycobacterium+tuberculosis.+Evidence+that+this+lipid+is+involved+in+the+cell+wall+permeability+barrier.">Analysis of the phthiocerol dimycocerosate locus of Mycobacterium tuberculosis. Evidence that this lipid is involved in the cell wall permeability barrier.</a> Journal of Biological Chemistry. 276 (23), 19845-19854 (2001).</li><li>Dhariwal, K. R., Chander, A., Venkitasubramanian, 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=Alterations+in+lipid+constituents+during+growth+of+Mycobacterium+smegmatis+CDC+46+and+Mycobacterium+phlei+ATCC+354.">Alterations in lipid constituents during growth of Mycobacterium smegmatis CDC 46 and Mycobacterium phlei ATCC 354.</a> Microbios. 16 (65-66), 169-182 (1976).</li><li>Chandramouli, V., Venkitasubramanian, 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=Effect+of+age+on+the+lipids+of+mycobacteria.">Effect of age on the lipids of mycobacteria.</a> Indian Journal of Chest Diseases &amp; Allied Sciences. 16, 199-207 (1982).</li><li>Hameed, S., Sharma, S., Fatima, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Techniques+to+understand+mycobacterial+lipids+and+use+of+lipid-based+nanoformulations+for+tuberculosis+management.">Techniques to understand mycobacterial lipids and use of lipid-based nanoformulations for tuberculosis management.</a> NanoBioMedicine. , (2020).</li><li>Folch, J., Lees, M., Sloane Stanley, G. 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+simple+method+for+the+isolation+and+purification+of+total+lipides+from+animal+tissues.">A simple method for the isolation and purification of total lipides from animal tissues.</a> The Journal of Biological Chemistry. 226 (1), 497-509 (1957).</li><li>Pal, R., Hameed, S., Kumar, P., Singh, S., Fatima, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+lipidome+profile+of+sensitive+and+resistant+Mycobacterium+tuberculosis+strain.">Comparative lipidome profile of sensitive and resistant Mycobacterium tuberculosis strain.</a> International Journal of Current Microbiology and Applied Sciences. 1 (1), 189-197 (2015).</li><li>Slayden, R. A., Barry, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+lipids+of+Mycobacterium+tuberculosis.">Analysis of the lipids of Mycobacterium tuberculosis.</a> Mycobacterium tuberculosis Protocols. 54, 229-245 (2001).</li><li>Ojha, A. K., 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=Growth+of+Mycobacterium+tuberculosis+biofilms+containing+free+mycolic+acids+and+harbouring+drug-tolerant+bacteria.">Growth of Mycobacterium tuberculosis biofilms containing free mycolic acids and harbouring drug-tolerant bacteria.</a> Molecular Microbiology. 69 (1), 164-174 (2008).</li><li>Ojha, A. K., Trivelli, X., Guerardel, Y., Kremer, L., Hatfull, G. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enzymatic+hydrolysis+of+trehalose+dimycolate+releases+free+mycolic+acids+during+mycobacterial+growth+in+biofilms.">Enzymatic hydrolysis of trehalose dimycolate releases free mycolic acids during mycobacterial growth in biofilms.</a> The Journal of Biological Chemistry. 285 (23), 17380-17389 (2010).</li><li>Layre, E., 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=Mycolic+acids+constitute+a+scaffold+for+mycobacterial+lipid+antigens+stimulating+CD1-restricted+T+cells.">Mycolic acids constitute a scaffold for mycobacterial lipid antigens stimulating CD1-restricted T cells.</a> Chemistry and Biology. 16 (1), 82-92 (2009).</li><li>Llorens-Fons, M., 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=Trehalose+polyphleates,+external+cell+wall+lipids+in+Mycobacterium+abscessus,+are+associated+with+the+formation+of+clumps+with+cording+morphology,+which+have+been+associated+with+virulence.">Trehalose polyphleates, external cell wall lipids in Mycobacterium abscessus, are associated with the formation of clumps with cording morphology, which have been associated with virulence.</a> Frontiers in Microbiology. 8, (2017).</li><li>Butler, W. R., Guthertz, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mycolic+acid+analysis+by+high-performance+liquid+chromatography+for+identification+of+mycobacterium+species.">Mycolic acid analysis by high-performance liquid chromatography for identification of mycobacterium species.</a> Clinical Microbiology Reviews. 14 (4), 704-726 (2001).</li><li>Teramoto, K., 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=Characterization+of+mycolic+acids+in+total+fatty+acid+methyl+ester+fractions+from+Mycobacterium+species+by+high+resolution+MALDI-TOFMS.">Characterization of mycolic acids in total fatty acid methyl ester fractions from Mycobacterium species by high resolution MALDI-TOFMS.</a> Mass Spectrometry. 4 (1), 0035 (2015).</li><li>Sartain, M. J., Dick, D. L., Rithner, C. D., Crick, D. C., Belisle, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipidomic+analyses+of+Mycobacterium+tuberculosis+based+on+accurate+mass+measurements+and+the+novel+"Mtb+LipidDB".">Lipidomic analyses of Mycobacterium tuberculosis based on accurate mass measurements and the novel "Mtb LipidDB".</a> Journal of Lipid Research. 52 (5), 861-872 (2011).</li><li>Li, M., Zhou, Z., Nie, H., Bai, Y., Liu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+of+chromatography+and+mass+spectrometry+in+lipidomics.">Recent advances of chromatography and mass spectrometry in lipidomics.</a> Analytical and Bioanalytical Chemistry. 399 (1), 243-249 (2011).</li><li>Nahar, A., Baker, A. L., Nichols, D. S., Bowman, J. P., Britz, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+Thin-Layer+Chromatography-Flame+Ionization+Detection+(TLC-FID)+to+total+lipid+quantitation+in+mycolic-acid+synthesizing+Rhodococcus+and+Williamsia+species.">Application of Thin-Layer Chromatography-Flame Ionization Detection (TLC-FID) to total lipid quantitation in mycolic-acid synthesizing Rhodococcus and Williamsia species.</a> International Journal of Molecular Sciences. 21 (5), 1670 (2020).</li></ol>

A simple protocol considered as the gold standard method for the extraction of noncovalently linked lipid compounds from the mycobacterial cell wall is presented. Further visualization by one- and two-dimensional TLCs from the extracted lipids of four different mycobacteria is shown.
Two consecutive combined mixtures of chloroform and methanol to recover the lipidic content of mycobacterial cells is the most widely used solvent mixture23,24<...

Mycobacterium is a genus that comprises pathogenic and non-pathogenic species, characterized by having a highly hydrophobic and impermeable cell wall formed by their peculiar lipids. Specifically, the mycobacterial cell wall contains mycolic acids, which are &#945;-alkyl and &#946;-hydroxy fatty acids, in which the &#945;-branch is constant in all mycolic acids (except for the length) and the &#946;-chain, called the meromycolate chain, is a long aliphatic chain that may contain different functional chemical groups described along with the literature (&#945;-, &#945;&#39;-, methoxy-, &#954;-, epoxy-, carboxy-, and &#969;-1-methoxy- mycolates), therefore producing seven types of mycolic acids (I-VII)1. Moreover, other lipids with unquestionable importance are also present in the cell wall of mycobacteria species. Pathogenic species such as Mycobacterium tuberculosis, the&#160;causative agent of tuberculosis2 produce specific lipid-based virulence factors such as phthiocerol dimycocerosates (PDIMs), phenolic glycolipid (PGL), di-, tri-, and penta-acyltrehaloses (DAT, TAT, and PAT), or sulfolipids, among others3. Their presence on the mycobacterial surface have been associated with the ability to modify the host immune response and therefore, the evolution and persistence of the mycobacterium inside the host4. For instance, the presence of triacylglycerols (TAG) has been associated with the hypervirulent phenotype of Lineage 2-Beijing sub-lineage of M. tuberculosis, possibly due to its capacity to attenuate the host immune response5,6. Other relevant lipids are lipooligosaccharides (LOSs) present in tuberculous and nontuberculous mycobacteria. In the case of Mycobacterium marinum, the presence of LOSs in its cell wall is related to sliding motility and the ability to form biofilms and interferes with recognition by macrophage pattern recognition receptors, affecting uptake and elimination of the bacteria by host phagocytes7,8. Additionally, the absence or presence of some lipids allows members of the same species to be classified into different morphotypes with virulent or attenuate profiles when interacting with host cells. For instance, the absence of glycopeptidolipids (GPL) in the rough morphotype of Mycobacterium abscessus has been associated with the ability to induce intraphagosomal acidification, and consequently cell apoptosis9, unlike the smooth morphotype that possesses GPLs in their surface. Furthermore, the lipid content of the mycobacterial cell wall is related to the ability to modify the immune response in the host. This is relevant in the context of using some mycobacteria to trigger a protective immune profile against different pathologies10,11,12,13.&#160;It has been demonstrated, for example, that Mycolicibacterium vaccae, a saprophytic mycobacterium, which is currently in phase III clinical trials as an immunotherapeutic vaccine for tuberculosis, display two colonial morphotypes. While the smooth phenotype, that contains a polyester in its surface, triggers a Th2 response, the rough phenotype devoid of the polyester can induce a Th1 profile when it interacts with host immune cells14. The repertoire of lipids present in the mycobacterial cell not only depends on mycobacteria species, but also on the conditions of mycobacterial cultures: time of incubation15,16 or composition of the culture medium17,18. In fact, changes in the culture medium composition affect the antitumor and immunostimulatory activity of M. bovis BCG&#160;and Mycolicibacterium brumae in vitro17. Moreover, the protective immune profile triggered by M. bovis BCG against M. tuberculosis challenge in mice models also depends on the culture media in which M. bovis BCG grows17. These could then be related to the lipid composition of the mycobacteria in each culture condition. For all these reasons, the study of the lipid content of mycobacteria is relevant. A visual procedure to extract and analyze the lipid composition of the mycobacterial cell wall is presented.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acetic Acid</td>
			<td>Merck</td>
			<td>100063</td>
			<td>CAUTION. Anhydrous for analysis EMSURE&#174; ACS,ISO,Reag. Ph Eur</td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Carlo Erba</td>
			<td>400971N</td>
			<td>CAUTION. ACETONE RPE-ACS-ISO FOR ANALYS ml 1000</td>
		</tr>
		<tr>
			<td>Anthrone</td>
			<td>Merck</td>
			<td>8014610010</td>
			<td>Anthrone for synthesis.</td>
		</tr>
		<tr>
			<td>Benzene</td>
			<td>Carlo Erba</td>
			<td>426113</td>
			<td>CAUTION. Benzene RPE - For analysis - ACS 2.5 l</td>
		</tr>
		<tr>
			<td>Capillary glass tube</td>
			<td>Merck</td>
			<td>BR708709</td>
			<td>BRAND&#174;&#160;disposable BLAUBRAND&#174;&#160;micropipettes, intraMark</td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Carlo Erba</td>
			<td>412653</td>
			<td>CAUTION. Chloroform RS - For HPLC - Isocratic grade - Stabilized with ethanol 2.5 L</td>
		</tr>
		<tr>
			<td>Dry block heater</td>
			<td>J.P. Selecta</td>
			<td>7471200</td>
			<td></td>
		</tr>
		<tr>
			<td>Dicloromethane</td>
			<td>Carlo Erba</td>
			<td>412622</td>
			<td>CAUTION. Dichloromethane RS - For HPLC - Isocratic grade - Stabilized with amylene 2.5 L</td>
		</tr>
		<tr>
			<td>Diethyl ether</td>
			<td>Carlo Erba</td>
			<td>412672</td>
			<td>CAUTION. Diethyl ether RS - For HPLC - Isocratic grade - Not stabilized 2.5 L</td>
		</tr>
		<tr>
			<td>Ethyl Acetate</td>
			<td>Panreac</td>
			<td>1313181211</td>
			<td>CAUTION. Ethyl acetate (Reag. USP, Ph. Eur.) for analysis, ACS, ISO</td>
		</tr>
		<tr>
			<td>Ethyl Alcohol Absolute</td>
			<td>Carlo Erba</td>
			<td>4146072</td>
			<td>CAUTION. Ethanol absolute anhydrous RPE - For analysis - ACS - Reag. Ph.Eur. - Reag. USP 1 L</td>
		</tr>
		<tr>
			<td>Glass funnel</td>
			<td>VidraFOC</td>
			<td>DURA.2133148 1217/1</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass tube</td>
			<td>VidraFOC</td>
			<td>VFOC.45066A-16125</td>
			<td>Glass tube with PTFE recovered cap</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Carlo Erba</td>
			<td>412722</td>
			<td>CAUTION. Methanol RS - For HPLC - GOLD - Ultragradient grade 2.5 L</td>
		</tr>
		<tr>
			<td>Molybdatophosphoric acid hydrate</td>
			<td>Merck</td>
			<td>51429-74-4</td>
			<td>CAUTION.</td>
		</tr>
		<tr>
			<td>Molybdenum Blue Spray Reagent, 1.3%</td>
			<td>Sigma</td>
			<td>M1942-100ML</td>
			<td>CAUTION.</td>
		</tr>
		<tr>
			<td>n-hexane</td>
			<td>Carlo Erba</td>
			<td>446903</td>
			<td>CAUTION. n-Hexane 99% RS - ATRASOL - For traces analysis 2.5 L</td>
		</tr>
		<tr>
			<td>n-nitroso-n-methylurea</td>
			<td>Sigma</td>
			<td>N4766</td>
			<td>CAUTION</td>
		</tr>
		<tr>
			<td>Orbital shaking platform</td>
			<td>DDBiolab</td>
			<td>995018</td>
			<td>NB-205L benchtop shaking incubator</td>
		</tr>
		<tr>
			<td>Petroleum ether (60-80&#186;C)</td>
			<td>Carlo Erba</td>
			<td>427003</td>
			<td>CAUTION. Petroleum ether 60 - 80&#176;C RPE - For analysis 2.5 L</td>
		</tr>
		<tr>
			<td>Sprayer</td>
			<td>VidraFOC</td>
			<td>712/1</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium sulphate anhydrous</td>
			<td>Merck</td>
			<td>238597</td>
			<td></td>
		</tr>
		<tr>
			<td>Sulfuric acid 95-97%</td>
			<td>Merck</td>
			<td>1007311000</td>
			<td>CAUTION. Sulfuric acid 95-97%</td>
		</tr>
		<tr>
			<td>TLC chamber</td>
			<td>Merck</td>
			<td>Z204226-1EA</td>
			<td>Rectangular TLC developing tanks, complete L &#215; H &#215; W 22 cm &#215; 22 cm &#215; 10 cm</td>
		</tr>
		<tr>
			<td>TLC plate</td>
			<td>Merck</td>
			<td>1057210001</td>
			<td>TLC SilicaGel 60- 20x20 cm x 25 u</td>
		</tr>
		<tr>
			<td>TLC Plate Heater</td>
			<td>CAMAG</td>
			<td>223306</td>
			<td>CAMAG TLC Plat Heater III</td>
		</tr>
		<tr>
			<td>Toluene</td>
			<td>Carlo Erba</td>
			<td>488551</td>
			<td>CAUTION. Toluene RPE - For analysis - ISO - ACS - Reag.Ph.Eur. - Reag.USP 1 L</td>
		</tr>
		<tr>
			<td>Vortex</td>
			<td>Fisher Scientific</td>
			<td>10132562</td>
			<td>IKA&#160;Agitador IKA v&#243;rtex 3</td>
		</tr>
		<tr>
			<td>1-naphthol</td>
			<td>Sigma-Aldrich</td>
			<td>102269427</td>
			<td>CAUTION.</td>
		</tr>
	</tbody>
</table>

analysis of the lipid composition of mycobacteria by thin layer chromatography

Mycobacteria species can differ from one another in the rate of growth, presence of pigmentation, the colony morphology displayed on solid media, as well as other phenotypic characteristics. However, they all have in common the most relevant character of mycobacteria: its unique and highly hydrophobic cell wall. Mycobacteria species contain a membrane-covalent linked complex that includes arabinogalactan, peptidoglycan, and long-chains of mycolic acids with types that differ between mycobacteria species. Additionally, mycobacteria can also produce lipids that are located, non-covalently linked, on their cell surfaces, such as phthiocerol dimycocerosates (PDIM), phenolic glycolipids (PGL), glycopeptidolipids (GPL), acyltrehaloses (AT), or phosphatidil-inositol mannosides (PIM), among others. Some of them are considered virulence factors in pathogenic mycobacteria, or critical antigenic lipids in host-mycobacteria interaction. For these reasons, there is a significant interest in the study of mycobacterial lipids due to their application in several fields, from understanding their role in the pathogenicity of mycobacteria infections, to a possible implication as immunomodulatory agents for the treatment of infectious diseases and other pathologies such as cancer. Here, a simple approach to extract and analyze the total lipid content and the mycolic acid composition of mycobacteria cells grown in a solid medium using mixtures of organic solvents is presented. Once the lipid extracts are obtained, thin-layer chromatography (TLC) is performed to monitor the extracted compounds. The example experiment is performed with four different mycobacteria: the environmental fast-growing Mycolicibacterium brumae and Mycolicibacterium fortuitum, the attenuated slow-growing Mycobacterium bovis bacillus Calmette-Gu&#233;rin (BCG), and the opportunistic pathogen fast-growing Mycobacterium abscessus, demonstrating that methods shown in the present protocol can be used to a wide range of mycobacteria.

With the aim of showing a wide range of lipids present in different mycobacteria species, M. bovis BCG was selected as it is rough and slow-growing mycobacteria. The rough and fast-growing M. fortuitum and M. brumae were added in the procedure and, finally, the smooth morphotype of M. abscessus was also included. These four species permit us to visualize a broad spectrum of mycobacteria-derived lipids such as acyltrehaloses (AT), GPLs, PDIM, PGL, PIM, TDM, and TMM. Moreover, all four s...

Watch this Scientific Journal Video about Analysis of the Lipid Composition of Mycobacteria by Thin Layer Chromatography at JoVE.com

Analysis of the Lipid Composition of Mycobacteria by Thin Layer Chromatography

A protocol is presented to extract the total lipid content of the cell wall of a wide range of mycobacteria. Moreover, extraction and analytical protocols of the different types of mycolic acids are shown. A thin-layer chromatographic protocol to monitor these mycobacterial compounds is also provided.

Mycobacteria species can differ from one another in the rate of growth, presence of pigmentation, the colony morphology displayed on solid media, as well ...

Mycobacteria Lipids are an important characteristic of the genus and are critical in host Mycobacteria interactions. Speed and versatility are the main advantages of this procedure. This method can be used to understand the role of lipids and the pathogenicity of mycobacteria and their immunostimulatory effect.For the non-covalent linked lipids extraction, add 15 milliliters of one to two chloroform to methanol solution to a glass tube with a PTFE liner screw cap under a laminar flow hood. Then, scratch 200 milligrams of mycobacteria from a solid medium, and add the mycobacteria to the glass tube. Incubate the tube overnight with constant stirring.On the next day, filter the organic solvents through a glass funnel lined with filter paper into a glass tube. After using nitrogen gas flux, to evaporate the liquid phase in the tube, fill the tube with nitrogen gas, to store the tube at four degrees Celsius. Then, add 15 milliliters of a two to one chloroform to methanol solution to the cellular debris and incubate the tube overnight with constant stirring.On the next morning, allow the mixture to rest for one hour, before using a Pasteur pipette to transfer the organic solvents into a filter paper lined glass funnel into the same glass collection tube. Then, evaporate the liquid phase as demonstrated, before refilling the tube with nitrogen gas for four degrees Celsius storage. For mycolic acid extraction, add two to five milliliters of a stirifying solution and 200 milligrams of mycobacteria biomass to a hermetic glass tube with a PTFE liner screw cap, and to mix the contents by vortexing.Incubate the mixture inside a dry bath at 80 degrees Celsius overnight. The next day, when the tube has cooled room temperature, add two milliliters of N hexane, and to mix the contents for 30 seconds by vortexing. Allow the tube to settle until two clear phases appear and transfer the upper N hexane phase to a new tube.Mix two additional milliliters of N hexane with the tube contents and collect the upper layer again. Then, evaporate the tube contents by nitrogen flow and store the sample covered in nitrogen at four degrees Celsius as demonstrated. To analyze the samples by TLC cover one wall of the TLC chamber with a piece of filter paper, add Vaseline on the chamber corners to seal the chamber, to can the solvent mixture over the filter paper and add the remaining volume of the solvent to the bottom of the TLC chamber.Close the TLC chamber for at least 20 minutes to saturated. Meanwhile, dissolve the lipids in the glass tube in 200 to 1000 microliters of chloroform and use a capillary glass tube to apply 10 microliters of the lipid chloroform suspension directly onto the TLC plate. After allowing the sample to dry for five minutes, insert the plate into the saturated TLC chamber and allow the mobile phase to run through the TLC.When the solvent reaches one centimeter from the upper end of the plate, place the plate under laminar flux until the silica is completely dry. Then, spray the dried plate with 15 to 20 milliliters of 10%molar data phosphoric acid hydrate in ethanol until the plate is bright yellow, and heat the plate for two to five minutes at 120 degrees Celsius. In this representative analysis, the mycolic acid extracted from various mycobacteria species, were analyzed through one dimensional TLC using two different elution systems and two dimensional TLC.Two types of methylation procedures were also performed to confirm the presence of type five mycolic acid. In both elution systems, the mycolic acids were located approximately in the middle of the plate, although, the spot corresponding to type five mycolic acid, was observed only after saponification. Two dimensional TLC also allows the identification of individual mycolic acid types.For example, mycobacterium brumae expresses only type one mycolic acids, mycobacterium bovis BCG expresses type one and four, mycobacterium fortuitum expresses type one and five, and mycobacterium abcessus expresses type one and two mycolic acid profiles. The total lipid extracts from various mycobacteria species were analyzed in function of their polarity and size. It reveals that most A polar lipids, such as PDIMs, are present in mycobacterium bovis BCG, but not in mycobacterium fortuitum, mycobacterium brumae and the smooth morphotype of M abcessus.Phenolic GlycoLipids are present only in mycobacterium bovis BCG, while GlycoPeptidoLipids are observed only in samples from mycobacterium abcessus. Similar to mycolic acids, Acylglycerols and PDIMs, PIMs, can also be easily visualized through one dimensional TLC or 2D TLC analysis. Two types of stains were used to reveal PIMs in one dimensional TLC.The most important thing to remember when attempting this protocol is to not use any plastic instruments throughout the procedure.

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7.3K Views.  Universitat Autònoma de Barcelona. I lipidi dei micobatteri sono una caratteristica importante del genere e sono fondamentali nelle interazioni dei micobatteri dell'ospite. Velocità e versatilità sono i principali vantaggi di questa procedura. Questo metodo può essere utilizzato per comprendere il ruolo dei lipidi e la patogenicità dei micobatteri e il loro effetto immunostimolante.Per l'estrazione di lipidi legati non covalenti, aggiungere 15 millilitri di uno o due cloroformio alla soluzione di metanolo a un tubo ...