Resumo

LOPEZ-PEREZ, Héctor M. et al. Adaptation of Mycobacterium smegmatis to nutrient depletion and its effect on esat-6 expression. Rev. mex. de cienc. pecuarias [online]. 2016, vol.7, n.1, pp.127-139. ISSN 2448-6698.

When resources are scarce, mycobacteria stop growing to make way for genes adaptation allow. Conversely, when growth continues under stress conditions, specific genes metabolic networks for protection are activating. In this sense, the protein encoded by esat-6 (early secretory antigenic target, 6 kDa) gene in Mycobacterium tuberculosis, acting in the lysis of alveolar epithelial and macrophage membranes to escape and invade other cells. But it can have other functions, such as interfering with cell-cell contact and transfer their DNA. In M. smegmatis, the ESX-1 (Secretion Ejectosoma BOX) system that facilitates secretion of ESAT-6 protein, probably it is sensitive to one or more nutrients of the culture medium. So it in the present study culture conditions limiting nutrient for growth of M. smegmatis are evaluated and relate the expression of esat-6. Culture media tested were minimal medium Hartmans Bond (HdB), carbon-limited (HdB<C), nitrogen (HdB<N) and inorganic phosphate (HdB<Pi). M. smegmatis HdB adapted to minimal medium, HdB<C and HdB<N and resume its metabolic activity in fresh medium, but not expressed esat-6. In HdB <Pi M. smegmatis loses its metabolic capacity for resistance acid-alcohol and expressed esat-6. Therefore, the culture media tested as a model for gene expression under nutrient limitation is proposed.

Palavras-chave : Metabolism; Dormancy; Adaptation; Stress; Nutrient depletion; Mycobacterium smegmatis; esat-6.

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