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Characterization of the L-form switch in the Gram-negative pathogen Streptobacillus moniliformis

Lookup NU author(s): Dr David Roberts, Dr Yoshikazu Kawai



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© The Author(s) 2021. Published by Oxford University Press on behalf of FEMS.Almost all major classes of bacteria are surrounded by a peptidoglycan cell wall, which is a crucial target for antibiotics. It is now understood that many bacteria can tolerate loss of the cell wall provided that they are in an isotonic environment. Furthermore, in some cases the cells can continue to proliferate in a state known as the L-form. L-form proliferation occurs by an unusual blebbing or tubulation mechanism that is completely independent of the normally essential division machine or cell wall synthetic enzymes, and is resistant to cell wall-active antibiotics. However, the growth is limited by reactive oxygen species generated by the respiratory chain pathway. In this work, we examined the walled to L-form transition in a pathogenic Gram-negative bacterium, Streptobacillus moniliformis, which naturally lacks the respiratory chain pathway, under aerobic conditions. L-form-like cells often emerged spontaneously, but proliferation was not observed unless the cells were treated with cell wall-active antibiotics. Time-lapse imaging revealed that cell division of S. moniliformis L-forms involves unusual membrane dynamics with an apparent imbalance between outer membrane and cytoplasmic volume growth. The results suggest that outer membrane expansion may be an important general factor for L-form proliferation of diderm bacteria.

Publication metadata

Author(s): Roberts DM, Errington J, Kawai Y

Publication type: Article

Publication status: Published

Journal: FEMS Microbiology Letters

Year: 2021

Volume: 368

Issue: 21-24

Print publication date: 01/12/2021

Online publication date: 15/12/2021

Acceptance date: 07/12/2021

Date deposited: 24/08/2023

ISSN (print): 0378-1097

ISSN (electronic): 1574-6968

Publisher: Oxford University Press


DOI: 10.1093/femsle/fnab156

PubMed id: 34910142


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Funder referenceFunder name
European Research Council
Wellcome Investigator Award
Wellcome Trust