Method Article

Analysis of the Lipid Composition of Mycobacteria by Thin Layer Chromatography

9K views

⸱

DOI:

10.3791/62368

⸱

April 16th, 2021

 ,  , 
1Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona

In This Article

Summary

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.

Abstract

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-Guérin (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.

Introduction

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 α-alkyl and β-hydroxy fatty acids, in which the α-branch is constant in all mycolic acids (except for the length) and the β-chain, called the meromycolate chain, is a long aliphatic chain that may contain different functional chemical groups described along with the literature (α-, α'-, methoxy-, κ-, epoxy-, carboxy-, and ω-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 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. 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 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.

Access restricted. Please log in or start a trial to view this content.

Protocol

1. Extraction of the total non-covalent-linked lipids from mycobacteria (Figure 1)

  1. 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.
    CAUTION: Chloroform is a potentially toxic and extremely hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Methanol is a potentially toxic and extremely hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
  2. Leave the tube in constant stirring overnight to extract non-covalent-linked lipids from the mycobacterial cell surface.
    NOTE: If an orbital shaking platform is not available, constant stirring can be replaced by periodic manual stirring as frequently as possible.
  3. Cover a glass funnel with a filter paper, filter the organic solvents, and collect them in a glass tube.
  4. Use a nitrogen gas flux to evaporate the liquid phase in the tube. Fill the tube with nitrogen gas, cover and store it at 4 °C.
    NOTE: Connect a glass Pasteur pipette to the stream of nitrogen gas to specifically evaporate the desired tube. Additionally, maintain the tube inside a dry block heater for tubes at 37 °C. When the solvent evaporates, fill the tube with nitrogen gas before closing it.
  5. Add 15 mL of a solution of chloroform:methanol (2:1) to the cellular debris. Leave the tube in constant stirring overnight to extract non-covalent-linked lipids from the mycobacterial cell surface.
    NOTE: If an orbital shaking platform is not available, constant stirring can be replaced by periodic manual stirring as frequently as possible.
  6. Let the mixture rest for 1 h. With a Pasteur pipette, recover the organic solvents. Cover a glass funnel with a filter paper and filter the organic solvents and collect them in the same glass tube previously used in step 1.3. Use a nitrogen gas flux to evaporate the liquid phase in the tube. Fill the tube with nitrogen gas, close it and store it again at 4 °C.

2. Mycolic acid extraction by acid methanolysis (Figure 2A)

  1. Add 2-5 mL of esterifying solution into a hermetic glass tube with a PTFE liner screw cap. Add 0.2 g of mycobacteria biomass into the glass tube.
    NOTE: Esterifying solution is formed by mixing 30 mL of methanol, 15 mL of toluene, and 1 mL of sulfuric acid. Mycobacteria cells can be taken from solid cultures or, even from delipidated cells after performing extraction of total non-covalent-linked lipids from mycobacteria (remaining cells after filtering in step 1.6).
    CAUTION: Toluene is a flammable and extremely hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Sulfuric acid is a corrosive and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
  2. Mix the content by vortexing. Let the mixture stand inside a dry bath at 80 °C overnight.
  3. Allow the tube to cool until it reaches the room temperature and then add 2 mL of n-hexane to the tube. Mix the contents by vortexing for 30 s and allow the tube to settle until two clear phases appear.
    CAUTION: n-hexane is a potential flammable, irritant, environmentally damaging, and extremely hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
  4. Recover the upper phase corresponding to the n-hexane phase. Transfer it to a new tube.
  5. Repeat the step 2.3. Recover the upper phase again and transfer it to the same tube used in step 2.4.
  6. Evaporate the contents of the tube using a nitrogen gas flux. Fill the tube with nitrogen gas, close it, and store it at 4 °C.

3. Mycolic acid extraction by saponification and methylation (Figure 2B)

  1. Scratch 0.2 g of mycobacteria from a solid media and add to a glass tube with a PTFE screw cap.
  2. Add 2 mL of methanol-benzene solution (80:20) containing 5% potassium hydroxide. Mix the contents by vortexing. Heat the mixture for 3 h at 100 °C.
    CAUTION: Benzene is a flammable, carcinogenic, and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
  3. Allow the tube to cool to room temperature. Add 20% sulfuric acid to acidify the samples to achieve pH = 1.
  4. Add 3 mL of diethyl ether. Gently mix the contents by vortexing.
  5. Let the two phases form by settling. Recover the diethyl ether phase and transfer to a new tube. Repeat the wash step for a total of three times.
  6. Wash the diethyl ether extract with 2 mL of distilled water and transfer the upper part corresponding to the diethyl ether to a new tube. Repeat the wash step for a total of three times.
  7. Add 2 g of anhydrous sodium sulfate over the diethyl ether extract to dry it.
  8. Filter the suspension. Evaporate the content using a nitrogen gas flux.
  9. To perform the methylation step, dissolve 3 g of N-nitroso-N-methyl urea in a precooled solution formed by 45 mL of diethyl ether and 9 mL of 40% KOH in distilled water.
    CAUTION: N-nitroso-N-methylurea is a toxic, irritant, carcinogenic, and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
  10. Transfer the supernatant (diazomethane) to a new flask cooled in ice containing potassium hydroxide pellets (approximately 30 g).
    NOTE: If the supernatant is not immediately used, it can be stored at -20 °C for a maximum of 1 h.
    CAUTION: Potassium hydroxide pellets are an irritant and corrosive substance. This material must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Diazomethane is highly toxic and potentially explosive. It must be used in a laminar flow hood with safety glass wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
  11. Add 2 mL of the ether solution containing diazomethane, obtained in step 3.10, into the dried diethyl ether extract that contains mycolic acids, obtained in step 3.8. Incubate for 15 min at room temperature.
  12. Evaporate the suspension at 40 °C. Fill the tube with nitrogen gas, close it, and store the methylated lipids at 4 °C.
    ​NOTE: Evaporate the diazomethane from the ether solution under the laminar flow hood, until the ether loses the yellow color.

4. Thin layer chromatography (TLC) analysis

  1. Saturate the glass TLC chamber. To do this, cover one of the walls of the TLC chamber with a piece of filter paper and allow it to be in contact with the mobile phase composed by the mixture of solvents. Place the remaining volume of the solvent onto the bottom of the TLC chamber.
    NOTE: The bottom of the TLC chamber must be covered by at least 1 cm of the mobile phase. In the present experiments, different mobile phases were used to develop the TLCs. They consisted of 85 mL of n-hexane plus 15 mL of diethyl ether; 100 mL of dichloromethane; 90 mL of chloroform, 10 mL of methanol, and 1 mL of water; 30 mL of chloroform, plus 8 mL of methanol, and 1 mL of water; 60 mL of chloroform, plus 35 mL of methanol, and 8 mL of water; 95 mL chloroform plus 5 mL of methanol; and 90 mL of petroleum ether (60-80 °C) plus 10 mL of diethyl ether.
    NOTE: In the two-dimensional TLC, use n-hexane:acetone (95:5) in the first direction three times, and use a single development with toluene:acetone (97:3) in the second direction to analyze mycolic acid composition. To analyze PIMs, use chloroform:methanol:water (60:30:6) in the first direction once, and use chloroform:acetic acid:methanol:water (40:25:3:6) in the second direction. To analyze PDIM and AG, use petroleum ether (60-80 °C):ethyl acetate (98:2) in the first direction three times, and use a single development with petroleum ether (60-80 °C):acetone (98:2) in the second direction.
    CAUTION: Diethyl ether is a potentially toxic and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Dichloromethane is a potentially toxic and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Petroleum ether is a potential flammable, environmentally damaging and extremely hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Acetic acid is a potential flammable and corrosive substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Ethyl acetate is a flammable and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Acetone is a flammable and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
  2. Close the TLC chamber to saturate it for at least 20 min. Meanwhile, dissolve the lipids present in the glass tube in 0.2-1 mL of chloroform.
    NOTE: The volume used to dissolve the lipids can be modified depending on the desired or expected concentration of the sample.
  3. Apply 10 µL of each suspension using a capillary glass tube directly on the TLC plate and let the sample dry for 5 min at room temperature.
    NOTE: Samples must be applied at the bottom part of the plate leaving 1 cm on each side. Samples must be separated one from another for at least 0.5 cm. Once the sample is applied on the plate, tubes can be evaporated again with nitrogen gas and stored at 4 °C for further use.
  4. Insert the plate into the saturated TLC chamber containing the mobile phase. Allow the mobile phase to run through the TLC.
    NOTE: Any movement applied to the TLC chamber affects the running solvent on the plate and affects lipid mobility. In the case of performing two-dimensional TLC, two TLC chambers are required to contain both elution systems.
  5. Remove the plate from the TLC chamber when the solvent reaches 1 cm distance from the upper end of the plate. Leave the plate under laminar flux until the silica is totally dried.
    NOTE: In the case of analyzing the mycolic acid composition, using n-hexane and diethyl-ether (85:15), repeat steps 4.4 and 4.5 two times more, until running the mobile phase three times over the TLC plate.
  6. Reveal the plate with the required stain; heat the plate if required.
    NOTE: In the present experiment, 15-20 mL of the following solutions were used to spray the TLC plates: 10% Molybdatophosphoric acid hydrate in ethanol until the plate is bright yellow, followed by heating the plate at 120 °C; 5% in ethanol of 20% α-naphthol in sulfuric acid followed by heating the plate at 120 °C; Molybdenum Blue reagent (1.3% molybdenum oxide in 4.2 M sulfuric acid) until phosphate bands appeared or 1% anthrone in sulfuric acid.
    CAUTION: Molybdatophosphoric acid hydrate is a flammable and corrosive substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Ethanol is a potential flammable and hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: 1-Naphthol is a flammable, corrosive, and extremely hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).
    CAUTION: Molybdenum Blue Spray Reagent is a corrosive, toxic, and extremely hazardous substance. It must be used in a laminar flow hood wearing appropriate personal protective equipment (laboratory coat, protective eyewear, and nitrile gloves).

Access restricted. Please log in or start a trial to view this content.

Results

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...

Access restricted. Please log in or start a trial to view this content.

Discussion

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<...

Access restricted. Please log in or start a trial to view this content.

Disclosures

The authors have nothing to disclose.

Acknowledgements

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.

Access restricted. Please log in or start a trial to view this content.

Materials

List of materials used in this article
NameCompanyCatalog NumberComments
Acetic AcidMerck100063CAUTION. Anhydrous for analysis EMSURE® ACS,ISO,Reag. Ph Eur
AcetoneCarlo Erba400971NCAUTION. ACETONE RPE-ACS-ISO FOR ANALYS ml 1000
AnthroneMerck8014610010Anthrone for synthesis.
BenzeneCarlo Erba426113CAUTION. Benzene RPE - For analysis - ACS 2.5 l
Capillary glass tubeMerckBR708709BRAND® disposable BLAUBRAND® micropipettes, intraMark
ChloroformCarlo Erba412653CAUTION. Chloroform RS - For HPLC - Isocratic grade - Stabilized with ethanol 2.5 L
Dry block heaterJ.P. Selecta7471200
DicloromethaneCarlo Erba412622CAUTION. Dichloromethane RS - For HPLC - Isocratic grade - Stabilized with amylene 2.5 L
Diethyl etherCarlo Erba412672CAUTION. Diethyl ether RS - For HPLC - Isocratic grade - Not stabilized 2.5 L
Ethyl AcetatePanreac1313181211CAUTION. Ethyl acetate (Reag. USP, Ph. Eur.) for analysis, ACS, ISO
Ethyl Alcohol AbsoluteCarlo Erba4146072CAUTION. Ethanol absolute anhydrous RPE - For analysis - ACS - Reag. Ph.Eur. - Reag. USP 1 L
Glass funnelVidraFOCDURA.2133148 1217/1
Glass tubeVidraFOCVFOC.45066A-16125Glass tube with PTFE recovered cap
MethanolCarlo Erba412722CAUTION. Methanol RS - For HPLC - GOLD - Ultragradient grade 2.5 L
Molybdatophosphoric acid hydrateMerck51429-74-4CAUTION.
Molybdenum Blue Spray Reagent, 1.3%SigmaM1942-100MLCAUTION.
n-hexaneCarlo Erba446903CAUTION. n-Hexane 99% RS - ATRASOL - For traces analysis 2.5 L
n-nitroso-n-methylureaSigmaN4766CAUTION
Orbital shaking platformDDBiolab995018NB-205L benchtop shaking incubator
Petroleum ether (60-80ºC)Carlo Erba427003CAUTION. Petroleum ether 60 - 80°C RPE - For analysis 2.5 L
SprayerVidraFOC712/1
Sodium sulphate anhydrousMerck238597
Sulfuric acid 95-97%Merck1007311000CAUTION. Sulfuric acid 95-97%
TLC chamberMerckZ204226-1EARectangular TLC developing tanks, complete L × H × W 22 cm × 22 cm × 10 cm
TLC plateMerck1057210001TLC SilicaGel 60- 20x20 cm x 25 u
TLC Plate HeaterCAMAG223306CAMAG TLC Plat Heater III
TolueneCarlo Erba488551CAUTION. Toluene RPE - For analysis - ISO - ACS - Reag.Ph.Eur. - Reag.USP 1 L
VortexFisher Scientific10132562IKA Agitador IKA vórtex 3
1-naphtholSigma-Aldrich102269427CAUTION.

References

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

Access restricted. Please log in or start a trial to view this content.

Reprints and Permissions

Request permission to reuse the text or figures of this JoVE article

Request Permission

Tags

Mycobacteria LipidsLipid ExtractionMycolic Acid AnalysisMycobacterial Cell WallOrganic Solvent ExtractionOne Dimensional TLCTwo Dimensional TLCPhenolic GlycolipidsGlycopeptidolipids

Related Articles