The Rcs Stress Response and Accessory Envelope Proteins Are Required for De Novo Generation of Cell Shape in Escherichia coli

Abstract

Interactions with immune responses or exposure to certain antibiotics can remove the peptidoglycan wall of many Gram-negative bacteria. Though the spheroplasts thus created usually lyse, some may survive by resynthesizing their walls and shapes. Normally, bacterial morphology is generated by synthetic complexes directed by FtsZ and MreBCD or their homologues, but whether these classic systems can recreate morphology in the absence of a preexisting template is unknown. To address this question, we treated Escherichia coli with lysozyme to remove the peptidoglycan wall while leaving intact the inner and outer membranes and periplasm. The resulting lysozyme-induced (LI) spheroplasts recovered a rod shape after four to six generations. Recovery proceeded via a series of cell divisions that produced misshapen and branched intermediates before later progeny assumed a normal rod shape. Importantly, mutants defective in mounting the Rcs stress response and those lacking penicillin binding protein 1B (PBP1B) or LpoB could not divide or recover their cell shape but instead enlarged until they lysed. LI spheroplasts from mutants lacking the Lpp lipoprotein or PBP6 produced spherical daughter cells that did not recover a normal rod shape or that did so only after a significant delay. Thus, to regenerate normal morphology de novo, E. coli must supplement the classic FtsZ-and MreBCD-directed cell wall systems with activities that are otherwise dispensable for growth under normal laboratory conditions. The existence of these auxiliary mechanisms implies that they may be required for survival in natural environments, where bacterial walls can be damaged extensively or removed altogether.

Retraction: Characterization of giant spheroplasts generated from the aerobic anoxygenic photosynthetic marine bacterium <i>Roseobacter litoralis</i>

“…1A, 1B, and 2B). Although elongated cells are also found in the recovery of (small) spheroplasts of E. coli (Ranjit and Young, 2013), the length is much shorter than that of the filamentous cells of R. litoralis. The culture media pH increased between 56 h and 78 h of growth (Fig.…”

“…Although the cell wall is a crucial structure in most of bacteria, it is a wonder why the cell wall lacking bacteria can live. Recovery of spheroplasts of Escherichia coli has been reported (Ranjit and Young, 2013). In addition, recovery of Lysozyme (200 µg/mL) was added to the cell suspension, and the suspension was shaken at 29°C for 15 min at 60 rpm.…”

Rod-like bacterial shape is maintained by feedback between cell curvature and cytoskeletal localization

“…S7A). In addition, we used antibiotics to convert WT rod-shaped cells into proliferating L-forms that lack a cell wall (31,32), and observed that L-forms failed to label with flWGA (Fig. S7 B-G).…”

Requirement of dark culture condition for enlargement of spheroplasts of the aerobic anoxygenic photosynthetic marine bacterium <i>Erythrobacter litoralis</i>

“…Although DNA replication is generally related to cell division, spheroplasts have been shown to replicate their DNA without undergoing cell division under incubation conditions (Takahashi and Nishida, 2015). Furthermore, spheroplasts from Escherichia coli can recover to their native cellular morphology via cell wall resynthesis (Ranjit and Young, 2013).…”

“…Although DNA replication is generally related to cell division, spheroplasts have been shown to replicate their DNA without undergoing cell division under incubation conditions (Takahashi and Nishida, 2015). Furthermore, spheroplasts from Escherichia coli can recover to their native cellular morphology via cell wall resynthesis (Ranjit and Young, 2013).In this study, we evaluated DNA replication and cell morphology of spheroplasts from Erythrobacter litoralis during growth in the absence and presence of penicillin at different temperatures, in order to determine the optimal conditions for growth of Erythrobacter litoralis spheroplasts. …”