Search results for "(Escherichia coli)"
showing 10 items of 689 documents
Activation of the contact-phase system on bacterial surfaces--a clue to serious complications in infectious diseases.
1998
Fever, hypotension and bleeding disorders are common symptoms of sepsis and septic shock. The activation of the contact-phase system is thought to contribute to the development of these severe disease states by triggering proinflammatory and procoagulatory cascades; however, the underlying molecular mechanisms are obscure. Here we report that the components of the contact-phase system are assembled on the surface of Escherichia coli and Salmonella through their specific interactions with fibrous bacterial surface proteins, curli and fimbriae. As a consequence, the proinflammatory pathway is activated through the release of bradykinin, a potent inducer of fever, pain and hypotension. Absorpt…
Characterization of PAMP/PRR interactions in European eel (Anguilla anguilla) macrophage-like primary cell cultures
2013
The eel (Anguilla anguilla) has been identified as a vulnerable species with stocks dramatically declining over the past decade. In an effort to support the species from overfishing of wild stocks increased interest in eel aquaculture has been notable. In order to expand the scarce knowledge concerning the biology of this species significant research efforts are required in several fields of biology. The development of cell culture systems to study the immune response is a key step towards an increased understanding of the immune response and to develop resources to support further study in this threatened species. Macrophages are one of the most important effector cells of the innate immun…
Mn(II) complexes of scorpiand-like ligands. A model for the MnSOD active centre with high in vitro and in vivo activity
2015
Manganese complexes of polyamines consisting of an aza-pyridinophane macrocyclic core functionalised with side chains containing quinoline or pyridine units have been characterised by a variety of solution techniques and single crystal x-ray diffraction. Some of these compounds have proved to display interesting antioxidant capabilities in vitro and in vivo in prokaryotic (bacteria) and eukaryotic (yeast and fish embryo) organisms. In particular, the Mn complex of the ligand containing a 4-quinoline group in its side arm which, as it happens in the MnSOD enzymes, has a water molecule coordinated to the metal ion that shows the lowest toxicity and highest functional efficiency both in vitro …
Transcriptional regulation of theNε-fructoselysine metabolism inEscherichia coliby global and substrate-specific cues
2020
AbstractThermally processed food is an important part of the human diet. Heat-treatment, however, promotes the formation of so-called Amadori rearrangement products (ARPs), such as fructoselysine. The gut microbiota includingEscherichia colican utilize these compounds as a nutrient source. While the degradation route for fructoselysine is well described, regulation of the corresponding pathway genesfrlABCDremained poorly understood. Here we use bioinformatics combined with molecular and biochemical analyses and show that inE. coli, fructoselysine metabolism is tightly controlled at the transcriptional level. The global regulator Crp (CAP), as well as the alternative sigma factor σ32 (RpoH) …
The effect of probiotics on the genotoxicity of furazolidone.
2004
Antigenotoxic activity of probiotic bacteria against furazolidone was studied using the short-term bacterial assay SOS chromotest, with Escherichia coli PQ37 as the test organism. The supernatants from probiotic and furazolidone co-incubation exhibited rather strong suppression on SOS induction produced by furazolidone on E. coli PQ 37 (sfiA: lacZ). Genotoxicity inhibition was found for all strains of the examined bacteria belonging to three genera. The highest genotoxicity inhibition was detected for Bifidobacterium lactis Bb-12 (92.0%) and for Lactobacillus acidophilus T20 (81.9%).
Antibacterial activity of the enniatin B, produced by Fusarium tricinctum in liquid culture, and cytotoxic effects on Caco-2 cells.
2011
The enniatins (ENs) are bioactive compounds of hexadepsipeptidic structure produced by several strains of Fusarium sp. The EN B was purified from extracts of Fusarium tricinctum growth on liquid culture of potato dextrose broth (PDB), using a semipreparative liquid chromatography (LC) followed by an analytical LC. The purity and the structure of the isolated compound were confirmed by the determination of the extinction coefficient and with electrospray ionization-mass spectrometry (ESI-MS) study. The pure fraction of EN B was utilized to determine the antibiotic effects on several bacterial strains that are considered normally pathogens of the intestinal tract: Escherichia coli, Enterococc…
Isolation, purification and antibacterial effects of fusaproliferin produced by Fusariumsubglutinans in submerged culture.
2009
To evaluate the fusaproliferin (FUS) production, Fusariumsubglutinans ITEM 2404 was grown in a liquid medium of potato being this mycotoxin purified by high-performance liquid chromatography (HPLC) with a C18 semipreparative column using a mobile phase of acetonitrile/H(2)O using gradient conditions. The purity of the fusaproliferin was verified by analytical HPLC, ultraviolet absorbance measurements, LC/MS-MS, (1)H NMR spectroscopy. The isolated FUS was shown to be free of impurities and can be used as a standard for routine analysis. The pure fusaproliferin was utilized to study the biological activity on Escherichiacoli and Staphylococcusaureus. This study demostred that FUS not showed s…
Escherichia coli cytolethal distending toxin blocks the HeLa cell cycle at the G2/M transition by preventing cdc2 protein kinase dephosphorylation an…
1997
Cytolethal distending toxins (CDT) constitute an emerging heterogeneous family of bacterial toxins whose common biological property is to inhibit the proliferation of cells in culture by blocking their cycle at G2/M phase. In this study, we investigated the molecular mechanisms underlying the block caused by CDT from Escherichia coli on synchronized HeLa cell cultures. To this end, we studied specifically the behavior of the two subunits of the complex that determines entry into mitosis, i.e., cyclin B1, the regulatory unit, and cdc2 protein kinase, the catalytic unit. We thus demonstrate that CDT causes cell accumulation in G2 and not in M, that it does not slow the progression of cells th…
The Cell Cycle-Specific Growth-Inhibitory Factor Produced by Actinobacillus actinomycetemcomitans Is a Cytolethal Distending Toxin
1998
ABSTRACT Actinobacillus actinomycetemcomitans has been shown to produce a soluble cytotoxic factor(s) distinct from leukotoxin. We have identified in A. actinomycetemcomitans Y4 a cluster of genes encoding a cytolethal distending toxin (CDT). This new member of the CDT family is similar to the CDT produced by Haemophilus ducreyi . The CDT from A. actinomycetemcomitans was produced in Escherichia coli and was able to induce cell distension, growth arrest in G 2 /M phase, nucleus swelling, and chromatin fragmentation in HeLa cells. The three proteins, CDTA, -B and -C, encoded by the cdt locus were all required for toxin activity. Antiserum raised against recombinant CDTC completely inhibited …
Type III Secretion-Dependent Cell Cycle Block Caused in HeLa Cells by Enteropathogenic Escherichia coliO103
2001
ABSTRACT Rabbit enteropathogenic Escherichia coli (EPEC) O103 induces in HeLa cells an irreversible cytopathic effect characterized by the recruitment of focal adhesions, formation of stress fibers, and inhibition of cell proliferation. We have characterized the modalities of the proliferation arrest and investigated its underlying mechanisms. We found that HeLa cells that were exposed to the rabbit EPEC O103 strain E22 progressively accumulated at 4C DNA content and did not enter mitosis. A significant proportion of the cells were able to reinitiate DNA synthesis without division, leading to 8C DNA content. This cell cycle inhibition by E22 was abrogated in mutants lacking EspA, -B, and -D…