Involvement of N-acetylmuramyl-l-alanine amidases in cell separation and antibiotic-induced autolysis of Escherichia coli

2001 ◽  
Vol 41 (1) ◽  
pp. 167-178 ◽  
Author(s):  
Christoph Heidrich ◽  
Markus F. Templin ◽  
Astrid Ursinus ◽  
Melisa Merdanovic ◽  
Jürgen Berger ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Separation ◽  
Induced Autolysis

scholarly journals Induction and control of the autolytic system of Escherichia coli

1982 ◽  
Vol 152 (1) ◽  
pp. 26-34
Author(s):  
M Leduc ◽  
R Kasra ◽  
J van Heijenoort
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid ◽  
Acid Synthesis ◽  
Induction Method ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Carbonyl Cyanide ◽  
And Control ◽  
First Time ◽  
Induced Autolysis

Various methods of inducing autolysis of Escherichia coli cells were investigated, some being described here for the first time. For the autolysis of growing cells only induction methods interfering with the biosynthesis of peptidoglycan were taken into consideration, whereas with harvested cells autolysis was induced by rapid osmotic or EDTA shock treatments. The highest rates of autolysis were observed after induction by moenomycin, EDTA, or cephaloridine. The different autolyses examined shared certain common properties. In particular, regardless of the induction method used, more or less extensive peptidoglycan degradation was observed, and 10(-2) M Mg2+ efficiently inhibited the autolytic process. However, for other properties a distinction was made between methods used for growing cells and those used for harvested cells. Autolysis of growing cells required RNA, protein, and fatty acid synthesis. No such requirements were observed with shock-induced autolysis performed with harvested cells. Thus, the effects of Mg2+, rifampicin, chloramphenicol, and cerulenin clearly suggest that distinct factors are involved in the control of the autolytic system of E. Coli. Uncoupling agents such as sodium azide, 2,4-dinitrophenol, and carbonyl-cyanide-m-chlorophenyl hydrazone used at their usual inhibiting concentration had no effect on the cephaloridine or shock-induced autolysis.

scholarly journals Growth of Escherichia coli: Significance of Peptidoglycan Degradation during Elongation and Septation

2008 ◽  
Vol 190 (11) ◽  
pp. 3914-3922 ◽  
Author(s):  
Tsuyoshi Uehara ◽  
James T. Park
Keyword(s):  
Escherichia Coli ◽  
Cell Elongation ◽  
Cell Separation ◽  
New Method ◽  
Striking Difference ◽  
Penicillin Binding Protein ◽  
Rapid Degradation ◽  
Lytic Transglycosylases ◽  
Daughter Cells ◽  
Rapid Removal

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.

scholarly journals Evidence for polarity of chromosome replication in F−strains ofEscherichia coli

1966 ◽  
Vol 8 (1) ◽  
pp. 119-124 ◽  
Author(s):  
W. D. Donachie ◽  
Millicent Masters
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Dna Replication ◽  
Cell Separation ◽  
Chromosome Replication ◽  
Ofescherichia Coli ◽  
Cell Cycles ◽  
Gene Replication ◽  
Serine Deaminase

The inducibility of three enzymes (β-galactosidase, tryptophanase and D-serine deaminase) has been measured at various times during the cell cycles of three strains ofEscherichia coli(K12 58–161 F−, B/r F–and 15T−). In each strain sharp increases in inducibility of these enzymes occurred at characteristic periods in each cell cycle. Such increases depend on DNA replication and therefore probably reflect synchronized gene replication. It is inferred that chromosome replication in these F−strains is sequential from a fixed origin.Infection with F′Lack+results in an extra period of increase in inducibiity of β-galactosidase in each cell cycle. It is concluded that the F′ episome replicates once in each cell cycle at a time soon after cell separation.

scholarly journals Characterization of Acp, a Peptidoglycan Hydrolase of Clostridium perfringens with N-Acetylglucosaminidase Activity That Is Implicated in Cell Separation and Stress-Induced Autolysis

2010 ◽  
Vol 192 (9) ◽  
pp. 2373-2384 ◽  
Author(s):  
Emilie Camiade ◽  
Johann Peltier ◽  
Ingrid Bourgeois ◽  
Evelyne Couture-Tosi ◽  
Pascal Courtin ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Clostridium Perfringens ◽  
Vegetative Growth ◽  
Cell Separation ◽  
Catalytic Domain ◽  
Peptidoglycan Hydrolase ◽  
Wild Type ◽  
Induced Autolysis

ABSTRACT This work reports the characterization of the first known peptidoglycan hydrolase (Acp) produced mainly during vegetative growth of Clostridium perfringens. Acp has a modular structure with three domains: a signal peptide domain, an N-terminal domain with repeated sequences, and a C-terminal catalytic domain. The purified recombinant catalytic domain of Acp displayed lytic activity on the cell walls of several Gram-positive bacterial species. Its hydrolytic specificity was established by analyzing the Bacillus subtilis peptidoglycan digestion products by coupling reverse phase-high-pressure liquid chromatography (RP-HPLC) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis, which displayed an N-acetylglucosaminidase activity. The study of acp expression showed a constant expression during growth, which suggested an important role of Acp in growth of C. perfringens. Furthermore, cell fractionation and indirect immunofluorescence staining using anti-Acp antibodies revealed that Acp is located at the septal peptidoglycan of vegetative cells during exponential growth phase, indicating a role in cell separation or division of C. perfringens. A knockout acp mutant strain was obtained by using the insertion of mobile group II intron strategy (ClosTron). The microscopic examination indicated a lack of vegetative cell separation in the acp mutant strain, as well as the wild-type strain incubated with anti-Acp antibodies, demonstrating the critical role of Acp in cell separation. The comparative responses of wild-type and acp mutant strains to stresses induced by Triton X-100, bile salts, and vancomycin revealed an implication of Acp in autolysis induced by these stresses. Overall, Acp appears as a major cell wall N-acetylglucosaminidase implicated in both vegetative growth and stress-induced autolysis.

scholarly journals The major autolysin ofStaphylococcus lugdunensis,AtlL, is involved in cell separation, stress-induced autolysis and contributes to bacterial pathogenesis

2014 ◽  
Vol 352 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Laure Gibert ◽  
Jennifer Didi ◽  
Lennart Marlinghaus ◽  
Olivier Lesouhaitier ◽  
Stéphanie Legris ◽  
...  
Keyword(s):  
Cell Separation ◽  
Bacterial Pathogenesis ◽  
Induced Autolysis

scholarly journals The active repertoire of Escherichia coli peptidoglycan amidases varies with physiochemical environment

2020 ◽  
Author(s):  
Elizabeth A. Mueller ◽  
Abbygail G. Iken ◽  
Mehmet Ali Öztürk ◽  
Mirko Schmitz ◽  
Barbara Di Ventura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Cell Separation ◽  
Antimicrobial Agents ◽  
Model Organism ◽  
Growth Conditions ◽  
Low Ph ◽  
E Coli ◽  
Ph Dependent ◽  
Stimulation Of

ABSTRACTNearly all bacteria are encased in a peptidoglycan cell wall, an essential crosslinked matrix of polysaccharide strands and short peptide stems. In the Gram-negative model organism Escherichia coli, more than forty cell wall synthases and autolysins coordinate the growth and division of the peptidoglycan sacculus in the periplasm. The precise contribution of many of these enzymes to cell wall metabolism remains unclear due to significant apparent redundancy, particularly among the cell wall autolysins. E. coli produces three major LytC-type-N-acetylmuramoyl-L-alanine amidases, which share a role in separating the newly formed daughter cells during cytokinesis. Here, we reveal two of the three amidases exhibit growth medium-dependent changes in activity. Specifically, we report acidic growth conditions stimulate AmiB—and to a lesser extent, AmiC—activity. Combining computational and genetic analysis, we demonstrate that low pH-dependent stimulation of AmiB requires three periplasmic amidase activators: EnvC, NlpD, and YgeR. Altogether, our findings support overlapping, but not redundant, roles for the E. coli amidases in cell separation and illuminate the physiochemical environment as an important mediator of cell wall enzyme activity.IMPORTANCEPenicillin and related β-lactam antibiotics targeting the bacterial cell wall synthesis are among the most commonly prescribed antimicrobials worldwide. However, rising rates of antibiotic resistance and tolerance jeopardize their continued clinical use. Development of new cell wall active therapeutics, including those targeting cell wall autolysins, has been stymied in part due to high levels of apparent enzymatic redundancy. In this study, we report a subset of E. coli amidases involved in cell separation during cell division are not redundant and instead are preferentially active during growth in distinct pH environments. Specifically, we discover E. coli amidases AmiB and AmiC are activated by acidic pH. Three semi-redundant periplasmic regulators—NlpD, EnvC, and YgeR—collectively mediate low pH-dependent stimulation of amidase activity. This discovery contributes to our understanding of how the cell wall remains robust across diverse environmental conditions and reveals opportunities for the development of condition-specific antimicrobial agents.

scholarly journals Characterization, Expression, and Mutation of the Lactococcus lactis galPMKTE Genes, Involved in Galactose Utilization via the Leloir Pathway

2003 ◽  
Vol 185 (3) ◽  
pp. 870-878 ◽  
Author(s):  
Benoît P. Grossiord ◽  
Evert J. Luesink ◽  
Elaine E. Vaughan ◽  
Alain Arnaud ◽  
Willem M. de Vos
Keyword(s):  
Escherichia Coli ◽  
Lactococcus Lactis ◽  
Cell Separation ◽  
Sole Carbon Source ◽  
Wild Type ◽  
Leloir Pathway ◽  
Wild Type Phenotype ◽  
Mutant Strains ◽  
Galactose Utilization ◽  
Long Chain

ABSTRACT A cluster containing five similarly oriented genes involved in the metabolism of galactose via the Leloir pathway in Lactococcus lactis subsp. cremoris MG1363 was cloned and characterized. The order of the genes is galPMKTE, and these genes encode a galactose permease (GalP), an aldose 1-epimerase (GalM), a galactokinase (GalK), a hexose-1-phosphate uridylyltransferase (GalT), and a UDP-glucose 4-epimerase (GalE), respectively. This genetic organization reflects the order of the metabolic conversions during galactose utilization via the Leloir pathway. The functionality of the galP, galK, galT, and galE genes was shown by complementation studies performed with both Escherichia coli and L. lactis mutants. The GalP permease is a new member of the galactoside-pentose-hexuronide family of transporters. The capacity of GalP to transport galactose was demonstrated by using galP disruption mutant strains of L. lactis MG1363. A galK deletion was constructed by replacement recombination, and the mutant strain was not able to ferment galactose. Disruption of the galE gene resulted in a deficiency in cell separation along with the appearance of a long-chain phenotype when cells were grown on glucose as the sole carbon source. Recovery of the wild-type phenotype for the galE mutant was obtained either by genetic complementation or by addition of galactose to the growth medium.

Sign in / Sign up

Export Citation Format

Share Document