Interaction of 5-substituted pyrimidine nucleoside analogues and M.Tuberculosis: A view through an electron microscope.

The data of transmission electron microscopy (TEM) on morphology of M. tuberculosis H37Rv bacterial cells treated with four analogues of pyrimidine nucleosides with different substituents at 5 position of base are presented. We showed that the growth of M. tuberculosis H37Rv cells effectively inhibited by each of these compounds. This process is accompanied with the accumulation of lipid intracellular vacuole-like inclusions in the cells, appearance of deep protrusions and indentations on the surface, partial and/or complete destruction of the three-layered cell envelope. The exact molecular mechanism of action of 5-substituted pyrimidine nucleosides on M. tuberculosis cells remains to be proved. However, one can suggest that mechanism of action for these compounds is related either to their direct interactions with bacteria cell walls or to interactions with enzymes participating in the process of cell wall formation.