Modulation of bacterial cell size and growth rate via activation of a cell envelope stress response

Abstract

Fluctuating conditions and diverse stresses are typical in natural environments. In response, cells mount complex responses across multiple scales, including adjusting their shape to withstand stress. In enterobacteria, the Rcs phosphorelay is activated by cell envelope damage and by changes to periplasmic dimensions and cell width. Here, we investigated the physiological and morphological consequences of Rcs activation in Escherichia coli in the absence of stresses, using an inducible version of RcsF that mislocalizes to the inner membrane, RcsFIM. Expression of RcsFIM immediately reduced cellular growth rate and the added length per cell cycle in a manner that was directly dependent on induction levels, but independent of Rcs-induced capsule production. At the same time, cells increased intracellular concentration of the cell division protein FtsZ, and decreased the distance between division rings in filamentous cells. Depletion of the Rcs negative regulator IgaA phenocopied RcsFIM induction, indicating that IgaA is essential due to growth inhibition in its absence. However, A22 treatment did not affect growth rate or FtsZ intracellular concentration, despite activating the Rcs system. These findings suggest that the effect of Rcs activation on FtsZ levels is mediated indirectly through growth-rate changes, and highlight feedbacks among the Rcs stress response, growth dynamics, and cell-size control.

Preventing E. coli Biofilm Formation with Antimicrobial Peptide-Functionalized Surface Coatings: Recognizing the Dependence on the Bacterial Binding Mode Using Live-Cell Microscopy

“…Decreased cell length homeostasis is indeed a characteristic of E. coli growing while subject to stress. 70 Toward the end of the experiment, a similar behavior was observed for bacteria subjected to AMC-25-04 as was seen for those bacteria subjected to AMC-109. A surprising observation was the formation of AMP nanoparticles, appearing on the surfaces early in experiments with AMC-109 and later AMC-25-04 ( Figure 3 h, lower panel).…”

“…Decreased cell length homeostasis is indeed a characteristic of E. coli growing while subject to stress . Toward the end of the experiment, a similar behavior was observed for bacteria subjected to AMC-25-04 as was seen for those bacteria subjected to AMC-109.…”

“…Knowing a bacterium’s identity, the evolution of its characteristics can be analyzed straightforwardly. We chose to measure the bacterial length as our main characteristic since the length and its derivate with respect to time, i.e., the GR, are good indicators of the metabolism of a rod-shaped bacterium and whether it is subject to stress. − Furthermore, for rod-shaped bacteria, the length measurement is relatively insensitive to noise or focus drift. Figure c shows the evolution of bacterial length for the individual bacteria (color-coded), and the boxplots of Figure e,f show the distribution of the GR and length, respectively, across the population at different times of the experiment.…”

Deciphering the adaption of bacterial cell wall mechanical integrity and turgor to different chemical or mechanical environments

“…This suggests that the cell wall stiffness and turgor of S. epidermidis are more sensitive to a medium with stronger ionic strength [13,56]. Our findings are important for understanding how bacterial cell shape and growth may vary in different osmotic environments [57,58]. In the simulations of Gram-negative bacterium, Klebsiella pneumoniae, Feng's group predicted a linear relation in the log-log plot for the normalized cell wall stiffness and normalized turgor [14].…”

“…Cell wall deformation induced by external mechanical and chemical stimuli can affect cell growth and shape [22,57,58,[63][64][65], and adhesion [6][7][8]10,66,67]. Fig.…”