scholarly journals The Action of Bacteriophage Ω8 on Two Strains of Escherichia coli 08

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 131-144 ◽  
Author(s):  
Barbara Wallenfels ◽  
K. Jann
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Phage Particle ◽  
Cytoplasmic Membrane ◽  
Cellular Respiration ◽  
Bacterial Strains ◽  
Viral Dna ◽  
Killing Effect ◽  
E Coli ◽  
Phage Propagation

Bacteriophage Ω8 is propagated in Escherichia coli E56b (08: K27-:H-), a non-capsulated strain. Another non-capsulated strain, E. coli 2398 (08:K?-:H-), is killed by bacteriophage Ω8 without phage propagation. This strain was formerly believed to be E. coli 093:K?-:H-, cross-reacting with strain E56b. We have established chemical and serological identity of the 08-specific lipopolysaccharides of the two strains. The 08-specific lipopolysaccharides of both strains inhibited the infection of Escherichia coli E56b with bacteriophage Ω8 equally well. The adsorption rate constants of Ω8 were identical for the two strains of E. coli 08. Evidence was obtained with 32P-labelled bacteriophage Ω8 for penetration of viral DNA into both bacterial strains. In host strain E56b, phage particle synthesis occurred normally. In strain 2398 the viral DNA was not degraded but its expression was blocked. The killing effect of Ω8 on E. coli strain 2398 is supposed to be due to damage of the cytoplasmic membrane, which could not be reversed under the influence of viral information. This was indicated by a blockage of cellular respiration, β-galactoside transport and RNA as well as protein synthesis.

Mode of action of bacteriophage &phi149 on cholera and E1 Tor vibrios

1978 ◽  
Vol 24 (12) ◽  
pp. 1583-1589 ◽  
Author(s):  
M. Maiti
Keyword(s):  
Vibrio Cholerae ◽  
Phage Particle ◽  
Small Degree ◽  
Cellular Respiration ◽  
Bacterial Strains ◽  
Killing Effect ◽  
Rate Dependent ◽  
Phage Dna ◽  
Rna And Protein Synthesis ◽  
Phage Propagation

Bacteriophage [Formula: see text] which was propagated in Vibrio cholerae (classical) OGAWA 154 strain, killed Vibrio cholerae (E1 Tor) strain MAK 757 without phage propagation. E1 Tor vibrios underwent a small degree of lysis only when infected by the phage [Formula: see text] at a high multiplicity of infection and lost their viability at a rate-dependent multiplicity of phage infection. Evidence was obtained with 32P-labelled bacteriophage [Formula: see text] for penetration of phage DNA into both bacterial strains. In host strain (OGAWA 154) phage particle synthesis occurred normally. In E1 Tor strain MAK 757 the phage DNA was not degraded but its expression was blocked. The killing effect of ([Formula: see text] on E1 Tor strain MAK 757 is supposed to be due to damage of the cytoplasmic membrane, which could not be repaired under the influence of phage information. This was indicated by a blockage of cellular respiration and 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.

Einfluß von 5-Azacytidin auf Reversion und UV-Sensibilität von Escherichia coli K12-Stämmen mit unterschiedlichen UVR-Genen / Influence of 5-Azacytidine on Reversion Rate and UV-Sensitivity of Escherichia coli K12 Strains with different UVR-Genes

1970 ◽  
Vol 25 (5) ◽  
pp. 537-542 ◽  
Author(s):  
R. Grunow ◽  
E. Geissler
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Phenotypic Expression ◽  
View Point ◽  
Reversion Rate ◽  
Bacterial Strains ◽  
Simultaneous Treatment ◽  
E Coli ◽  
Uv Sensitivity ◽  
Escherichia Coli K12

3 µg AC/ml cause an inhibition of cell division of E. coli K12 strains. This concentration is not mutagenic, because the reversion frequencies of the markers thr-, his- and arg- are not changed by AC treatment. However the reversion frequencies of thr- and arg- increased 1 to 4 orders of magnitude after UV irradiation, simultaneous treatment with AC and UV decreased these enlarged reversion rates at 1 exponent. The marker his- used in this experiments is not reverted by UV.The UV-sensitivity of bacterial strains with different uvr-genes is studied. The results are discussed from the view point that the influence of AC caused an inhibition of protein synthesis, whereby phenotypic expression of UV induced DNA damage is delayed and the time for repair of DNA is enlarged.

Interaction of Gram-Negative Bacteria with the Lysosomal Fraction of Polymorphonuclear Leukocytes II. Changes in the Cell Envelope of Escherichia coli

1970 ◽  
Vol 1 (3) ◽  
pp. 311-318
Author(s):  
D. Friedberg ◽  
I. Friedberg ◽  
M. Shilo
Keyword(s):  
Escherichia Coli ◽  
Polymorphonuclear Leukocytes ◽  
Cytoplasmic Membrane ◽  
Morphological Changes ◽  
Cell Envelope ◽  
Gram Negative Bacteria ◽  
Intact Cells ◽  
Lysosomal Fraction ◽  
E Coli ◽  
Absorbing Material

Interaction of lysosomal fraction with Escherichia coli caused damage to the cell envelope of these intact cells and to the cytoplasmic membrane of E. coli spheroplasts. The damage to the cytoplasmic membrane was manifested in the release of 260-nm absorbing material and β-galactosidase from the spheroplasts, and by increased permeability of cryptic cells to O -nitrophenyl-β- d -galactopyranoside; damage to the cell wall was measured by release of alkaline phosphatase. Microscope observation showed morphological changes in the cell envelope.

Enterohemorrhagic Escherichia coli Colony Check Assay for the Identification of Serogroups O26, O45, O103, O111, O121, O145, and O157 Colonies Isolated on Plating Media

2014 ◽  
Vol 77 (7) ◽  
pp. 1212-1218 ◽  
Author(s):  
BURTON BLAIS ◽  
MYLÈNE DESCHÊNES ◽  
GEORGE HUSZCZYNSKI ◽  
MARTINE GAUTHIER
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
High Throughput Screening ◽  
Enterohemorrhagic Escherichia Coli ◽  
Test Results ◽  
Bacterial Strains ◽  
Enrichment Broth ◽  
Substrate Solution ◽  
E Coli ◽  
Assay Performance

A simple immunoenzymatic enterohemorrhagic Escherichia coli (EHEC) colony check (ECC) assay was developed for the presumptive identification of priority EHEC colonies isolated on plating media from enrichment broth cultures of foods. With this approach, lipopolysaccharide extracted from a colony is spotted on the grid of a polymyxin-coated polyester cloth strip, and bound E. coli serogroup O26, O45, O103, O111, O121, O145, and O157 antigens are subsequently detected by sequential reactions with a pool of commercially available peroxidase-conjugated goat antibodies and tetramethylbenzidine substrate solution. Each strip can accommodate up to 15 colonies, and test results are available within 30 min. Assay performance was verified using colonies from a total of 73 target EHEC isolates covering the range of designated priority serogroups (all of which were reactive), 41 nontarget E. coli isolates including several nontarget Shiga toxin–producing E. coli serogroups (all unreactive), and 33 non–E. coli strains (all unreactive except two bacterial strains possessing O-antigenic structures in common with those of the priority EHEC). The ECC assay was reactive with target colonies grown on several types of selective and nonselective plating media designed for their cultivation. These results support the use of the ECC assay for high-throughput screening of colonies isolated on plating media for detecting priority EHEC strains in foods.

scholarly journals The orientation of iron–sulphur clusters in membrane multilayers prepared from aerobically-grown Escherichia coli K12 and a cytochrome-deficient mutant

1980 ◽  
Vol 190 (2) ◽  
pp. 385-393 ◽  
Author(s):  
Haywood Blum ◽  
Robert K. Poole ◽  
Tomoko Ohnishi
Keyword(s):  
Magnetic Field ◽  
Escherichia Coli ◽  
Cytoplasmic Membrane ◽  
Deficient Mutant ◽  
E Coli ◽  
Membrane Particles ◽  
Degree Of Orientation ◽  
High Degree ◽  
Cytochrome Content ◽  
The Magnetic Field

1. Membrane particles prepared from ultrasonically-disrupted, aerobically-grown Escherichia coli were centrifuged on to a plastic film that was supported perpendicular to the centrifugal field to yield oriented membrane multilayers. In such preparations, there is a high degree of orientation of the planes of the membranes such that they lie parallel to each other and to the supporting film. 2. When dithionite- or succinate-reduced multilayers are rotated in the magnetic field of an e.p.r. spectrometer, about an axis lying in the membrane plane, angular-dependent signals from an iron–sulphur cluster at gx=1.92, gy=1.93 and gz=2.02 are seen. The g=1.93 signal has maximal amplitude when the plane of the multilayer is perpendicular to the magnetic field. Conversely, the g=2.02 signal is maximal when the plane of the multilayer is parallel with the magnetic field. 3. Computer simulations of the experimental data show that the cluster lies in the cytoplasmic membrane with the gy axis perpendicular to the membrane plane and with the gx and gz axes lying in the membrane plane. 4. In partially-oxidized multilayers, a signal resembling the mitochondrial high-potential iron–sulphur protein (Hipip) is seen whose gz=2.02 axis may be deduced as lying perpendicular to the membrane plane. 5. Appropriate choice of sample temperature and receiver gain reveals two further signals in partially-reduced multilayers: a g=2.09 signal arises from a cluster with its gz axis in the membrane plane, whereas a g=2.04 signal is from a cluster with the gz axis lying along the membrane normal. 6. Membrane particles from a glucose-grown, haem-deficient mutant contain dramatically-lowered levels of cytochromes and exhibit, in addition to the iron–sulphur clusters seen in the parental strain, a major signal at g=1.90. 7. Only the latter may be demonstrated to be oriented in multilayer preparations from the mutant. 8. Comparisons are drawn between the orientations of the iron–sulphur proteins in the cytoplasmic membrane of E. coli and those in mitochondrial membranes. The effects of diminished cytochrome content on the properties of the iron–sulphur proteins are discussed.

scholarly journals Susceptibility of Escherichia coli and Clostridium perfringens to sucrose monoesters of capric and lauric acid

2014 ◽  
Vol 59 (No. 8) ◽  
pp. 374-380
Author(s):  
E. Skřivanová ◽  
Š. Pražáková ◽  
O. Benada ◽  
P. Hovorková ◽  
MarounekM
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Clostridium Perfringens ◽  
Lauric Acid ◽  
Cytoplasmic Membrane ◽  
E Coli ◽  
Enteropathogenic Bacteria ◽  
Viable Cells ◽  
Transmission Electron ◽  
Cytoplasmic Structures

The sucrose monoesters of capric and lauric acid were tested for their antibacterial activity towards two foodborne enteropathogenic bacteria &ndash; Escherichia coli (CCM 3954 &ndash; serotype O6 and E22 &ndash; serotype O103) and Clostridium perfringens (CNCTC 5459 and CIP 105178). Antibacterial activity was evaluated by the plating technique. Sucrose monocaprate significantly decreased the number of viable cells of E. coli at all tested concentrations (0.1&ndash;5 mg/ml). The overnight incubation of C. perfringens with the sucrose ester of lauric acid at 0.1&ndash;5 mg/ml reduced the number of viable cells below the detection limit (2 log<sub>10</sub> CFU/ml). Incubating E. coli CCM 3954 and C. perfringens CNCTC 5459 with monoesters (0.1 and 2 mg/ml) did not influence the K<sup>+</sup> permeability of the cytoplasmic membrane in cells during a 2.5-minute treatment. A 30-minute incubation of E. coli CCM 3954 and C. perfringens CNCTC 5459 with esters (0.1 and 2 mg/ml) revealed damage to cytoplasmic structures, as observed by transmission electron microscopy. &nbsp;

scholarly journals Utilization of Mn-Doped ZnSe/ZnS Core/Shell Quantum Dots for Rapid Detection of Escherichia coli O157:H7 and Methicillin-Resistant Staphylococcus aureus

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Thi-Diem Bui ◽  
Quang-Liem Nguyen ◽  
Thi-Bich Luong ◽  
Van Thuan Le ◽  
Van-Dat Doan
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Quantum Dots ◽  
Fluorescent Labeling ◽  
Core Shell ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
Methicillin Resistant ◽  
E Coli ◽  
Mn Doped

In this study, Mn-doped ZnSe/ZnS core/shell quantum dots (CSQDs) were synthesized in aqueous solution using polyethylene glycol as a surface stabilizer and successfully applied in the detection of Escherichia coli O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA) for the first time. The CSQDs were conjugated with anti-E. coli antibody and anti-MRSA antibody via protein A supported by 1-ethyl-3-(-3-dimethylaminopropyl)carbodiimide hydrochloride for fluorescent labeling of the intact bacterial cells. The detection was performed for the bacterial strains cultivated in Luria-Bertani liquid medium. The obtained results indicate that E. coli O157:H7 and MRSA can be detected within 30 min at a high sensitivity of 101 CFU/mL. This labeling method based on the highly fluorescent CSQDs may have great potential for use in the food industry to check and prevent outbreaks of foodborne illness.

scholarly journals 617. Efficacy of Dimercaptosuccinic Acid (DMSA), a Zinc Chelator, in Combination with Imipenem Against Metallo-β-Lactamase Producing Escherichia coli in a Murine Peritonitis Model

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S287-S287
Author(s):  
Geoffrey Cheminet ◽  
Patrice Nordmann ◽  
Francoise Chau ◽  
Nicolas Kieffer ◽  
Katell Peoc’h ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Maximum Effect ◽  
Dependent Manner ◽  
Bacterial Strains ◽  
Concentration Dependent Manner ◽  
Bacterial Counts ◽  
E Coli ◽  
Zinc Chelator ◽  
Peritonitis Model

Abstract Background A strategy used by bacterial strains to resist β-lactam antibiotics is the expression of metallo-β-lactamases (MBL) requiring zinc for activity. The use of a zinc chelator may restore carbapenem activity against MBL-producing Enterobacteriaceae. DMSA is a heavy metal chelator approved in humans with a satisfactory safety record. Our objective was to evaluate the activity of DMSA in combination with carbapenems, in vitro and in a fatal murine peritonitis model, against MBL-producing Escherichia coli. Methods Isogenic derivatives of wild-type E. coli CFT073 producing the MBL NDM-1, VIM-2, IMP-1, and the serine carbapenemases OXA-48 and KPC-3 were constructed. Minimum inhibitory concentrations (MICs) of imipenem, meropenem, and ertapenem were determined against each strain alone or in combination with DMSA. Mice were infected with E. coli CFT073 or NDM-1 and treated intraperitoneally for 24 hours with imipenem 100 mg/kg every 4 hours, DMSA 200 mg/kg every 4 hours, or both. Mice survival rates and bacterial counts in peritoneal fluid (PF) and spleen were assessed at 24 hours. Results In vitro, DMSA in combination with each carbapenem permitted a significant decrease of the MICs against all MBL-producing strains, in a concentration-dependent manner. The maximum effect was found for the NDM-1 strain with a 6- to 8-fold MIC reduction, depending on the carbapenem used. NDM-1 strain became susceptible to carbapenems with concentrations of DMSA ≥6 mM. Increasing zinc concentrations above 1 mg/L (average human plasma concentration) did not alter this effect. No benefit of DMSA was observed against non-MBL strains. In vivo, when used alone, the DMSA regimen was not toxic in uninfected mice and ineffective against NDM-1-infected mice (100% mortality). Combination of imipenem and DMSA significantly reduced bacterial counts in PF and spleen as compared with imipenem alone (P < 0.001), and reduced mortality, although not significantly (11% vs. 37%, respectively, P = 0.12). No benefit of the combination was observed against CFT073. Conclusion DMSA is highly effective in vitro in reducing carbapenems MICs against MBL-producing E. coli and appears as a promising strategy in combination with carbapenems for the treatment of NDM-1-related infections. Disclosures All authors: No reported disclosures.

scholarly journals Phospholipid distribution in the cytoplasmic membrane of Gram-negative bacteria is highly asymmetric, dynamic, and cell shape-dependent

2020 ◽  
Vol 6 (23) ◽  
pp. eaaz6333 ◽  
Author(s):  
Mikhail Bogdanov ◽  
Kyrylo Pyrshev ◽  
Semen Yesylevskyy ◽  
Sergey Ryabichko ◽  
Vitalii Boiko ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Physical Properties ◽  
Cell Shape ◽  
Yersinia Pseudotuberculosis ◽  
Cytoplasmic Membrane ◽  
The Other ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Phospholipid Distribution

The distribution of phospholipids across the inner membrane (IM) of Gram-negative bacteria is unknown. We demonstrate that the IMs of Escherichia coli and Yersinia pseudotuberculosis are asymmetric, with a 75%/25% (cytoplasmic/periplasmic leaflet) distribution of phosphatidylethanolamine (PE) in rod-shaped cells and an opposite distribution in E. coli filamentous cells. In initially filamentous PE-lacking E. coli cells, nascent PE appears first in the periplasmic leaflet. As the total PE content increases from nearly zero to 75%, cells progressively adopt a rod shape and PE appears in the cytoplasmic leaflet of the IM. The redistribution of PE influences the distribution of the other lipids between the leaflets. This correlates with the tendency of PE and cardiolipin to regulate antagonistically lipid order of the bilayer. The results suggest that PE asymmetry is metabolically controlled to balance temporally the net rates of synthesis and translocation, satisfy envelope growth capacity, and adjust bilayer chemical and physical properties.

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