Document Detail

Unstable Escherichia coli L forms revisited: growth requires peptidoglycan synthesis.
MedLine Citation:
PMID:  17586646     Owner:  NLM     Status:  MEDLINE    
Growing bacterial L forms are reputed to lack peptidoglycan, although cell division is normally inseparable from septal peptidoglycan synthesis. To explore which cell division functions L forms use, we established a protocol for quantitatively converting a culture of a wild-type Escherichia coli K-12 strain overnight to a growing L-form-like state by use of the beta-lactam cefsulodin, a specific inhibitor of penicillin-binding proteins (PBPs) 1A and 1B. In rich hypertonic medium containing cefsulodin, all cells are spherical and osmosensitive, like classical L forms. Surprisingly, however, mutant studies showed that colony formation requires d-glutamate, diaminopimelate, and MurA activity, all of which are specific to peptidoglycan synthesis. High-performance liquid chromatography analysis confirmed that these L-form-like cells contain peptidoglycan, with 7% of the normal amount. Moreover, the beta-lactam piperacillin, a specific inhibitor of the cell division protein PBP 3, rapidly blocks the cell division of these L-form-like cells. Similarly, penicillin-induced L-form-like cells, which grow only within the agar layers of rich hypertonic plates, also require d-glutamate, diaminopimelate, and MurA activity. These results strongly suggest that cefsulodin- and penicillin-induced L-form-like cells of E. coli-and possibly all L forms-have residual peptidoglycan synthesis which is essential for their growth, probably being required for cell division.
Danièle Joseleau-Petit; Jean-Claude Liébart; Juan A Ayala; Richard D'Ari
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Publication Detail:
Type:  Journal Article     Date:  2007-06-22
Journal Detail:
Title:  Journal of bacteriology     Volume:  189     ISSN:  0021-9193     ISO Abbreviation:  J. Bacteriol.     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-09-03     Completed Date:  2007-10-19     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6512-20     Citation Subset:  IM    
Institut Jacques Monod, 2 place Jussieu, 75251 Paris Cedex 05, France.
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MeSH Terms
Anti-Bacterial Agents / pharmacology
Cefsulodin / pharmacology
Cell Division
Cell Wall / chemistry
Culture Media
Escherichia coli / drug effects,  genetics,  growth & development*,  metabolism
L Forms / drug effects,  growth & development*
Peptidoglycan / biosynthesis*
Piperacillin / pharmacology
beta-Lactams / pharmacology
Reg. No./Substance:
0/Anti-Bacterial Agents; 0/Culture Media; 0/Peptidoglycan; 0/beta-Lactams; 61477-96-1/Piperacillin; 62587-73-9/Cefsulodin
Comment In:
J Bacteriol. 2007 Sep;189(18):6509-11   [PMID:  17644588 ]

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