Fig. 1

Different mechanisms of bacterial lysis by phages. A Lytic and lysogenic cycles of mycobacteriophages in M. tuberculosis. A1 The phage binds to M. tuberculosis using specific receptors and injects its genetic materials, A2 Phage DNA circularization occurs within the M. tuberculosis. Then, for particular reasons, the phage enters a lytic or a lysogenic cycle. In the case of the lytic cycle, A3a new phage proteins and DNA are produced and brought together in new viral elements. A4a The M. tuberculosis cells are lysed, and new viral particles are released. During the lysogenic cycle, A3b the phage genetic material is combined with the M. tuberculosis genome, and a prophage is produced. A4b The prophage will reproduce alongside the M. tuberculosis genome and will be transferred to the progeny that will gain new features. A5 In certain situations, the prophage genome will be cut from the bacterial genome, and the lytic cycle will be performed. B In most cases, mycobacteriophages lyse their host using the endolysin–holin systems. Holins act as membrane proteins to support and displace the lysins to attain their targets. Lysin A destroys the peptidoglycan, while Lysin B cuts the ester bonds between mycolic acids and the arabinogalactan to damage trehalose dimycolates (TDMs)