Incorporation of Radiolabelled Substrates into Mycobacteri- al Lipids of M. Bovis BCG and M. Kansasii

Background: Diseases caused by microorganisms of the genus Mycobacterium continue to be a serious problem. The cell envelope constitutes up to 60% of the dry weight of lipids. The cell wall of the mycobacterium is essential for their growth and survival in the infected host. The cell wall lipids have been isolated from M. bovis BCG and M. kansasii mycobacterial strains and studied the incorporation of radiolabelled substrates for exploring the potential involvement of lipid biosynthetic pathways. Methods: We have incubated M. bovis, BCG and M. kansasii with radiolabelled substrates-1-C14-palmitic acid, 1-C14-sodium-n-valerate, 1-C14-sodium-n-acetate and 1-C14-sodium-n-propionate and calculated the incorporation in PGL, PDIM and mycolates by Liquid Scintillation Counter. Results: We have found the percentage of assimilation of 1-C14-palmitic acid into lipids of M. bovis BCG and M. kansasii were PGL: 0.39%, PDIM: 0.70% & Mycolates: 0.30% and PGL: 0.42%, PDIM: 0.81% & Mycolates: 1.45% respectively. The percentage of assimilation of 1-C14-sodium-n-valerate into lipids of M. bovis BCG and M. kansasii were PGL: 0.28%, PDIM: 0.58% & Mycolates: 1.05% and PGL: 0.35%, PDIM: 0.68% & Mycolates: 0.90% respectively. The percentage of assimilation of 1-C14sodium-nacetate into lipids of M. bovis BCG and M. kansasii were PGL: 0.45%, PDIM: 0.80% & Mycolates: 1.45% and PGL: 0.48%, PDIM: 0.90% & Mycolates: 1.50% respectively. The percentage of assimilation of 1-C14-sodium-npropionate into lipids of M. bovis BCG & M. kansasii were PGL: 0.48%, PDIM: 0.85% & Mycolates: 1.40% and PGL: 0.50%, PDIM: 0.90% and Mycolates: 1.48% respectively. Conclusion: The findings of this study suggest the usefulness of radiolabelled substrate incorporation approach for exploring the involvement of lipid biosynthetic pathway.