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Fig. 5 | SpringerPlus

Fig. 5

From: Mechanism to control the cell lysis and the cell survival strategy in stationary phase under heat stress

Fig. 5

Generation of heat shock and the consequent mechanism of σE-dependent cell lysis. a Functional analysis of sodA and katE genes, involved in the evolution of reactive oxygen species (ROS). Mutation in sodA (encoding superoxide dismutase) and katE (encoding catalase) induces the generation of ROS which may render the viable and culturable cells to be damaged or into the VBNC state, which in turn undergoes the σE-directed lysis. Thus the defective cells are removed and only the culturable cells sustain thereby suggesting the phenomenon of programmed cell death (PCD). The idea is supported by overexpressing the sodA (SodA clone) and katE genes (KatE clone) whereby the ROS accumulation is considerably suppressed with a concomitant downregulation of the rpoE gene (encoding σE). b Possible mechanism of σE-dependent cell lysis whereby the role of ROS has been shown in the formation of the VBNC cells which have further undergone the lysis process with a concominant increased downregulation of peptidyl prolyl isomerise (PpiD) and the simultaneous upregulation of the micA and rybB genes encoding small RNAs. The repression of the expression of the outer membrane porins (OMPs) have also been detected which might be responsible for the impairment of the cell membrane integrity thereby rendering the cells to be lyzed

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