Role of lipid components in formation and reactivation of Mycobacterium smegmatis "nonculturable" cells.

We have found that transition of actively dividing Mycobacterium smegmatis cells into the dormant "nonculturable" state is accompanied by increase in the protein/lipid ratio and disappearance of one of the main lipid components of the mycobacterial cells, trehalose monomycolate. In this case, oleic acid is accumulated in the culture medium due to its secretion by the mycobacterial cells. Addition of lipids of different classes to "nonculturable" M. smegmatis cells induces their resuscitation. The lipid reactivating effect is evidently caused by the presence of fatty acids in their composition, because free fatty acids also exhibited reactivation effect. Oleic acid in concentration of 0.05-3 μg/ml exhibited maximal effect, and that allows us to draw a conclusion concerning its signal role in the transition of dormant cells into active state.