Lipid composition of cell wall of three species of environmental mycobacteria and its possible role in the biofilm formations and motility by sliding

The wall structures of Mycobacteria are usually associated with the abil­ity to form biofilm and motility by sliding. This study was performed with three strain of Environmental Mycobacteria (MA): Mycobacterium smegmatis, Mycobacterium gordonae and Mycobacterium porcinum. The goals of this paper were: a) to estab­lish by MALDI-TOF mass spectrometry (MS) whether there are differences in the lipid carbon chain composition in the cell wall when they are in plank­tonic growth or forming biofilm; b) to evaluate the relation between lipid carbon chain composition and their sliding and biofilm formation abil­ity. M. porcinum and M. smegmatis formed biofilms of different sizes and presented motility. M. gordonae devel­oped poor biofilm and did not move. MALDI-TOF spectra obtained from EM in a planktonic state differ from EM biofilm–grown ones in their cell–wall lipidic carbon chain composition. EM biofilm–grown spectra show a greater diversity. All biofilm–grown EM spec­tra present short chain mycolic acids. These results suggest the importance of these mycolic acids in the forma­tion of biofilm, especially in its matu­ration. M. gordonae presented also a higher proportion of long-chain fatty acid, compared to M. smegmatis and M. porcinum. The presence of long hy­drophobic chains could possibly gen­erate a greater friction, thus reducing its motility.