scholarly journals MazF-Mediated Cell Death in Escherichia coli: a Point of No Return

2004 ◽  
Vol 186 (24) ◽  
pp. 8295-8300 ◽  
Author(s):  
Shahar Amitai ◽  
Yussuf Yassin ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Inhibitory Effect ◽  
Luria Bertani ◽  
E Coli ◽  
Ectopic Overexpression ◽  
Point Of No Return ◽  
The Rich ◽  
Overexpression System

ABSTRACT mazEF is a stress-induced toxin-antitoxin module, located on the chromosome of Escherichia coli, that we have previously described to be responsible for programmed cell death in E. coli. mazF specifies a stable toxin, and mazE specifies a labile antitoxin. Recently, it was reported that inhibition of translation and cell growth by ectopic overexpression of the toxin MazF can be reversed by the action of the antitoxin MazE ectopically overexpressed at a later time. Based on these results, it was suggested that rather than inducing cell death, mazF induces a state of reversible bacteriostasis (K. Pederson, S. K. Christensen, and K. Gerdes, Mol. Microbiol. 45:501-510, 2002). Using a similar ectopic overexpression system, we show here that overexpression of MazE could reverse MazF lethality only over a short window of time. The size of that window depended on the nature of the medium in which MazF was overexpressed. Thus, we found “a point of no return,” which occurred sooner in minimal M9 medium than it did in the rich Luria-Bertani medium. We also describe a state in which the effect of MazF on translation could be separated from its effect on cell death: MazE overproduction could completely reverse the inhibitory effect of MazF on translation, while not affecting the bacteriocidic effect of MazF at all. Our results reported here support our view that the mazEF module mediates cell death and is part of a programmed cell death network.

scholarly journals Cell Death in Escherichia coli dnaE(Ts) Mutants Incubated at a Nonpermissive Temperature Is Prevented by Mutation in the cydA Gene

2004 ◽  
Vol 186 (7) ◽  
pp. 2147-2155 ◽  
Author(s):  
Bernard Strauss ◽  
Kemba Kelly ◽  
Toros Dincman ◽  
Damian Ekiert ◽  
Theresa Biesieda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Dna Synthesis ◽  
Dna Content ◽  
Electrophoretic Pattern ◽  
Luria Bertani ◽  
E Coli ◽  
Viable Cells ◽  
Rna And Protein Synthesis ◽  
Transformation Activity

ABSTRACT Cells of the Escherichia coli dnaE(Ts) dnaE74 and dnaE486 mutants die after 4 h of incubation at 40°C in Luria-Bertani medium. Cell death is preceded by elongation, is inhibited by chloramphenicol, tetracycline, or rifampin, and is dependent on cell density. Cells survive at 40°C when they are incubated at a high population density or at a low density in conditioned medium, but they die when the medium is supplemented with glucose and amino acids. Deletion of recA or sulA has no effect. We isolated suppressors which survived for long periods at 40°C but did not form colonies. The suppressors protected against hydroxyurea-induced killing. Sequence and complementation analysis indicated that suppression was due to mutation in the cydA gene. The DNA content of dnaE mutants increased about eightfold in 4 h at 40°C, as did the DNA content of the suppressed strains. The amount of plasmid pBR322 in a dnaE74 strain increased about fourfold, as measured on gels, and the electrophoretic pattern appeared to be normal even though the viability of the parent cells decreased 2 logs. Transformation activity also increased. 4′,6′-Diamidino-2-phenylindole staining demonstrated that there were nucleoids distributed throughout the dnaE filaments formed at 40°C, indicating that there was segregation of the newly formed DNA. We concluded that the DNA synthesized was physiologically competent, particularly since the number of viable cells of the suppressed strain increased during the first few hours of incubation. These observations support the view that E. coli senses the rate of DNA synthesis and inhibits septation when the rate of DNA synthesis falls below a critical level relative to the level of RNA and protein synthesis.

scholarly journals Postsegregational Killing Mediated by the P1 Phage “Addiction Module” phd-doc Requires the Escherichia coli Programmed Cell Death SystemmazEF

2001 ◽  
Vol 183 (6) ◽  
pp. 2046-2050 ◽  
Author(s):  
Ronen Hazan ◽  
Boaz Sat ◽  
Myriam Reches ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Protein Synthesis ◽  
Programmed Cell Death ◽  
Killing Effect ◽  
E Coli ◽  
Lethal Action ◽  
Free Cells ◽  
Postsegregational Killing

ABSTRACT “Addiction modules” consist of two genes; the product of the second is long lived and toxic, while the product of the first is short lived and antagonizes the lethal action of the toxin. The extrachromosomal addiction module phd-doc, located on the P1 prophage, is responsible for the postsegregational killing effect (death of plasmid-free cells). The Escherichia colichromosomal addiction module analogue, mazEF, is responsible for the induction of programmed cell death. Here we show that the postsegregational killing mediated by the P1phd-doc module depends on the presence of the E. coli mazEF system. In addition, we demonstrate that under conditions of postsegregational killing, mediated byphd-doc, protein synthesis of E. coli is inhibited. Based on our findings, we suggest the existence of a coupling between the phd-doc and mazEFsystems.

scholarly journals Programmed Cell Death in Escherichia coli: Some Antibiotics Can Trigger mazEFLethality

2001 ◽  
Vol 183 (6) ◽  
pp. 2041-2045 ◽  
Author(s):  
Boaz Sat ◽  
Ronen Hazan ◽  
Tova Fisher ◽  
Hanita Khaner ◽  
Gad Glaser ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Bacterial Chromosome ◽  
E Coli ◽  
Bacterial Cultures ◽  
Gene Pairs ◽  
System A ◽  
Extrachromosomal Elements

ABSTRACT The discovery of toxin-antitoxin gene pairs (also called addiction modules) on extrachromosomal elements of Escherichia coli, and particularly the discovery of homologous modules on the bacterial chromosome, suggest that a potential for programmed cell death may be inherent in bacterial cultures. We have reported on the E. coli mazEF system, a regulatable addiction module located on the bacterial chromosome. MazF is a stable toxin and MazE is a labile antitoxin. Here we show that cell death mediated by the E. coli mazEF module can be triggered by several antibiotics (rifampicin, chloramphenicol, and spectinomycin) that are general inhibitors of transcription and/or translation. These antibiotics inhibit the continuous expression of the labile antitoxin MazE, and as a result, the stable toxin MazF causes cell death. Our results have implications for the possible mode(s) of action of this group of antibiotics.

scholarly journals The Escherichia coli mazEF Suicide Module Mediates Thymineless Death

2003 ◽  
Vol 185 (6) ◽  
pp. 1803-1807 ◽  
Author(s):  
Boaz Sat ◽  
Myriam Reches ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Molecular Mechanism ◽  
Stress Conditions ◽  
E Coli ◽  
System A ◽  
Thymine Starvation ◽  
Thymineless Death

ABSTRACT In 1954, Cohen and Barner discovered that a thymine auxotrophic (thyA) mutant of Escherichia coli undergoes cell death in response to thymine starvation. This phenomenon, called thymineless death (TLD), has also been found in many other organisms, including prokaryotes and eukaryotes. Though TLD has been studied intensively, its molecular mechanism has not yet been explained. Previously we reported on the E. coli mazEF system, a regulatable chromosomal suicide module that can be triggered by various stress conditions. MazF is a stable toxin, and MazE is an unstable antitoxin. Here, we show that cell death that is mediated by the mazEF module can also be activated by thymine starvation. We found that TLD depends on E. coli mazEF and that under thymine starvation, the activity of the mazEF promoter P2 is significantly reduced. Our results, which describe thymine starvation as a trigger for a built-in death program, have implications for programmed cell death in both prokaryotes and eukaryotes.

scholarly journals “mazEFmediated programmed cell death in Escherichia coli”: is it?

2016 ◽  
Author(s):  
Bhaskar Chandra Mohan Ramisetty ◽  
Swati Raj ◽  
Dimpy Ghosh
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Stress Tolerance ◽  
Type Ii ◽  
Overlapping Genes ◽  
Wild Type ◽  
E Coli ◽  
Typical Type ◽  
Metabolic Fitness

AbstractToxin-antitoxins systems (TAS) are prokaryotic operons containing two small overlapping genes which encode two components referred to as Toxin and Antitoxin. Involvement of TAS in bacterial programmed cell death (PCD) is highly controversial. MazEF, a typical type II TAS, is particularly implicated in mediating PCD inEscherichia coli. Hence, we compared the metabolic fitness and stress tolerance ofE. colistrains (MC4100 and itsmazEF- derivative) which were extensively used by proponents ofmazEF- mediated PCD. We found that both the strains are deficient inrelAgene and that theΔmazEFstrain has lower fitness and stress tolerance compared to wild type MC4100. Furthermore, these strains are likely not isogenic. We could not reproducemazEFmediated PCD which emphasizes the need for skeptic approach to the PCD hypothesis.

scholarly journals Escherichia coli K12 Upregulates Programmed Cell Death Ligand 1 (PD-L1) Expression in Gamma Interferon-Sensitized Intestinal Epithelial Cells via the NF-κB Pathway

2020 ◽  
Vol 89 (1) ◽  
pp. e00618-20 ◽  
Author(s):  
Seul A. Lee ◽  
Yiming Wang ◽  
Fang Liu ◽  
Stephen M. Riordan ◽  
Lu Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Bacterial Species ◽  
Intestinal Epithelial ◽  
Content Type ◽  
E Coli ◽  
Inflammatory Conditions ◽  
Ifn Γ ◽  
Ht 29

ABSTRACTProgrammed cell death ligand-1 (PD-L1) is an immune checkpoint protein which is used by tumor cells for immune evasion. PD-L1 is upregulated in inflamed intestinal tissues. The intestinal tract is colonized by millions of bacteria, most of which are commensal bacterial species. We hypothesized that under inflammatory conditions, some commensal bacterial species contribute to increased PD-L1 expression in intestinal epithelium and examined this hypothesis. Human intestinal epithelial HT-29 cells with and without interferon (IFN)-γ sensitization were incubated with six strains of four enteric bacterial species. The mRNA and protein levels of PD-L1 in HT-29 cells were examined using quantitative real-time PCR and flow cytometry, respectively. The levels of interleukin (IL)-1β, IL-18, IL-6, IL-8, and tumor necrosis factor (TNF)-α secreted by HT-29 cells were measured using enzyme-linked immunosorbent assay. Apoptosis of HT-29 cells was measured using a caspase 3/7 assay. We found that Escherichia coli K12 significantly upregulated both PD-L1 mRNA and protein in IFN-γ-sensitized HT-29 cells. E. coli K12 induced the production of IL-8 in HT-29 cells, however, IL-8 did not affect HT-29 PD-L1 expression. Inhibition of the nuclear factor-kappa B pathway significantly reduced E. coli K12-induced PD-L1 expression in HT-29 cells. The other two E. coli strains and two enteric bacterial species did not significantly affect PD-L1 expression in HT-29 cells. Enterococcus faecalis significantly inhibited PD-L1 expression due to induction of cell death. Data from this study suggest that some gut bacterial species have the potential to affect immune function under inflammatory conditions via upregulating epithelial PD-L1 expression.

scholarly journals degS Is Necessary for Virulence and Is among Extraintestinal Escherichia coli Genes Induced in Murine Peritonitis

2003 ◽  
Vol 71 (6) ◽  
pp. 3088-3096 ◽  
Author(s):  
Peter Redford ◽  
Paula L. Roesch ◽  
Rodney A. Welch
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Luria Bertani ◽  
Broth Culture ◽  
Wild Type ◽  
E Coli ◽  
Virulence Attenuation

ABSTRACT Extraintestinal Escherichia coli strains cause meningitis, sepsis, urinary tract infection, and other infections outside the bowel. We examined here extraintestinal E. coli strain CFT073 by differential fluorescence induction. Pools of CFT073 clones carrying a CFT073 genomic fragment library in a promoterless gfp vector were inoculated intraperitoneally into mice; bacteria were recovered by lavage 6 h later and then subjected to fluorescence-activated cell sorting. Eleven promoters were found to be active in the mouse but not in Luria-Bertani (LB) broth culture. Three are linked to genes for enterobactin, aerobactin, and yersiniabactin. Three others are linked to the metabolic genes metA, gltB, and sucA, and another was linked to iha, a possible adhesin. Three lie before open reading frames of unknown function. One promoter is associated with degS, an inner membrane protease. Mutants of the in vivo-induced loci were tested in competition with the wild type in mouse peritonitis. Of the mutants tested, only CFT073 degS was found to be attenuated in peritoneal and in urinary tract infection, with virulence restored by complementation. CFT073 degS shows growth similar to that of the wild type at 37°C but is impaired at 43°C or in 3% ethanol LB broth at 37°C. Compared to the wild type, the mutant shows similar serum survival, motility, hemolysis, erythrocyte agglutination, and tolerance to oxidative stress. It also has the same lipopolysaccharide appearance on a silver-stained gel. The basis for the virulence attenuation is unclear, but because DegS is needed for σE activity, our findings implicate σE and its regulon in E. coli extraintestinal pathogenesis.

scholarly journals Induction of Escherichia coli Chromosomal mazEF by Stressful Conditions Causes an Irreversible Loss of Viability

2006 ◽  
Vol 188 (9) ◽  
pp. 3420-3423 ◽  
Author(s):  
Ilana Kolodkin-Gal ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Basic Characteristic ◽  
Irreversible Loss ◽  
Previous Conclusion ◽  
E Coli ◽  
Programmed Death

ABSTRACT mazEF is a stress-induced toxin-antitoxin module located on the chromosomes of many bacteria. Here we induced Escherichia coli chromosomal mazEF by various stressful conditions. We found an irreversible loss of viability, which is the basic characteristic of cell death. These results further support our previous conclusion that E. coli mazEF mediation of cell death is not a passive process, but an active and genetically “programmed” death response.

scholarly journals DIFFERENTIAL INHIBITORY EFFECTS OF CHOLERA TOXOIDS AND GANGLIOSIDE ON THE ENTEROTOXINS OF VIBRIO CHOLERAE AND ESCHERICHIA COLI

1973 ◽  
Vol 137 (4) ◽  
pp. 1009-1023 ◽  
Author(s):  
Nathaniel F. Pierce
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Competitive Inhibitor ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
E Coli ◽  
Stable Component ◽  
Heat Stable ◽  
Cholera Enterotoxin ◽  
Gut Mucosa

Natural cholera toxoid appears to act as a competitive inhibitor of cholera enterotoxin and is thus a useful tool for studying the interaction of cholera enterotoxin with cell membranes. Cholera enterotoxin binds to gut mucosa more rapidly than does its natural toxoid. Once binding occurs, however, it appears to be prolonged for both materials. Formalinized cholera toxoid has no inhibitory effect upon cholera enterotoxin. Enterotoxic activity, ability to bind to gut mucosa, and antitoxigenicity appear to be independent properties of cholera enterotoxin. Natural cholera toxoid does not inhibit Escherichia coli enterotoxin, indicating that although the two enterotoxins activate the same mucosal secretory mechanism they occupy different binding sites in the mucosa. Ganglioside, which may be the mucosal receptor of cholera enterotoxin, is highly efficient in deactivating cholera enterotoxin. By contrast, ganglioside is relatively inefficient in deactivating heat-labile E. coli enterotoxin and is without effect upon the heat-stable component of E. coli enterotoxin. These findings suggest that ganglioside is not likely to be the mucosal receptor for E. coli enterotoxin. Differences in cellular binding of E. coli and cholera enterotoxins may explain, at least in part, the marked differences in the time of onset and duration of their effects upon gut secretion.

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