Display Settings:

Format

Send to:

Choose Destination
J Bacteriol. 2008 Jun;190(11):3914-22. doi: 10.1128/JB.00207-08. Epub 2008 Apr 4.

Growth of Escherichia coli: significance of peptidoglycan degradation during elongation and septation.

Author information

  • 1Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA tsuyoshi_uehara@hms.harvard.edu

Abstract

We have found a striking difference between the modes of action of amdinocillin (mecillinam) and compound A22, both of which inhibit cell elongation. This was made possible by employment of a new method using an Escherichia coli peptidoglycan (PG)-recycling mutant, lacking ampD, to analyze PG degradation during cell elongation and septation. Using this method, we have found that A22, which is known to prevent MreB function, strongly inhibited PG synthesis during elongation. In contrast, treatment of elongating cells with amdinocillin, which inhibits penicillin-binding protein 2 (PBP2), allowed PG glycan synthesis to proceed at a nearly normal rate with concomitant rapid degradation of the new glycan strands. By treating cells with A22 to inhibit sidewall synthesis, the method could also be applied to study septum synthesis. To our surprise, over 30% of newly synthesized septal PG was degraded during septation. Thus, excess PG sufficient to form at least one additional pole was being synthesized and rapidly degraded during septation. We propose that during cell division, rapid removal of the excess PG serves to separate the new poles of the daughter cells. We have also employed this new method to demonstrate that PBP2 and RodA are required for the synthesis of glycan strands during elongation and that the periplasmic amidases that aid in cell separation are minor players, cleaving only one-sixth of the PG that is turned over by the lytic transglycosylases.

PMID:
18390656
[PubMed - indexed for MEDLINE]
PMCID:
PMC2395050
Free PMC Article

Images from this publication.See all images (3)Free text

FIG. 1.
FIG. 2.
FIG. 3.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk