GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Montrouge :John Libbey Eurotext,
    Keywords: Microbiology -- History. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (320 pages)
    Edition: 1st ed.
    ISBN: 9782742009121
    Series Statement: Médecine Sciences/Sélection
    DDC: 576.09
    Language: French
    Note: Une histoire des microbes -- Sommaire -- Préface -- Avant-propos -- Chapitre 1. L'aube de l'humanité -- Émergence des maladies infectieuses depuis le néolithique -- La boite de Pandore -- Chapitre 2. Le mythe de la générationspontanée de la vie -- Aristote et la génération spontanée -- Un monde en gésine : la Renaissance -- D'où viennent les vers ? -- Les insectes ont un sexe -- La découverte du sexe des plantes -- Leeuwenhoek et le monde invisible -- Spallanzani et les infusoires -- Pasteur et la fin de la théorie de la génération spontanée -- La génération spontanée au XXe siècle -- Chapitre 3. Du contagium vivumaux microbes -- L'origine des maladies dans l'Antiquité -- Le pressentiment des germes -- Hippocrate et la théorie des miasmes -- Fracastor et le contagium vivum -- Bonomo et la gale -- Mildiou et phylloxéra -- Muscardine et pébrine -- Ferments et maladies du vin -- Ergotisme et mycoses -- Le nosocomium et la fièvre puerpérale de Semmelweis -- La pourriture d'hôpital et Lister -- Les postulats de Henlé et Koch -- Porteurs sains et réservoirs de germes -- Chapitre 4. Les chemins de la découverte -- Créer les outils pour déceler les bactéries -- La lèpre et Armauer Hansen -- Robert Koch -- Le charbon -- La tuberculose -- Le choléra -- La peste et Alexandre Yersin -- La syphilis -- La première chasse aux bactéries pathogènes -- Une quête continuelle -- La maladie des légionnaires -- Les ulcères et les gastrites -- Nouvelles approches -- Chapitre 5. Sa Majesté des mouches -- Belzébuth -- L'éléphantiasis et David Manson -- La fièvre du Texas et Théobald Smith -- La maladie du sommeil et David Bruce -- Le mystérieux « mal noir » du Bengale -- La maladie de Carlos Chagas -- La fièvre jaune et Walter Reed -- Le paludisme, Ronald Ross et Giovanni Grassi -- Le typhus et Howard Ricketts -- La peste et Paul-Louis Simond. , La maladie de Lyme et Allen Steere -- L'encéphalite West Nile dans la « jungle » de New York -- Chapitre 6. La quête des plus petits microbes -- La filtration de l'eau -- La saga du virus de la mosaïque du tabac -- Les bactériophages, virus des bactéries -- La quête des premiers virus pathogènes -- Visualiser et cultiver les virus -- La saga des hépatites : de l'ictère des camps à la jaunisse d'inoculation -- Expériences humaines : l'éthique à rude épreuve -- L'heureuse découverte du virus de hépatite B -- La découverte du virus de l'hépatite C : le triomphe de la biologie moléculaire -- Burkitt et la découverte du premier virus oncogène humain -- Une dernière surprise : les viroïdes -- Épilogue -- Chapitre 7. Le coup de tonnerre du sida -- Les premiers rétrovirus -- L'enzyme hérétique -- Les maladies virales d'évolution lente -- L'émergence d'une maladie inconnue -- Le sarcome de Kaposi -- L'éclosion de l'épidémie -- Découverte des premiers rétrovirus humains -- La quête du virus du sida -- Transfusion et « sang impur » -- Origine du HIV -- La pandémie de SIDA aujourd'hui -- Chapitre 8. Le pandémonium des virus émergents -- El typho negro et fièvre de Lassa -- Les mystères des filovirus -- Les pandémies de grippe -- Mystérieuses maladies disparues -- Grippes malignes et nouveaux virus -- Chapitre 9. L'intimité des microbes -- La double hélice et le dogme de la biologie moléculaire -- La lecture et la synthèse des molécules de la vie -- Les outils du génie génétique -- Naissance de la bio-informatique -- La course aux génomes des microbes -- La découverte de la PCR -- L'énigme des pétunias et l'interférence virale -- La classification moléculaire des microbes -- Chapitre 10. « Magic Bullets » -- Le secret de « l'écorce sacrée » -- De l'industrie des colorants aux antibiotiques -- Paul Ehrlich et le salvarsan -- Gerhard Domagk et les sulfamides. , Serendipity et la pénicilline -- Les premiers antibiotiques contre la tuberculose -- La découverte des médicaments antiviraux -- Les analogues de nucléosides et Gertrude Elion -- Chapitre 11. Imiter la nature -- La variolisation -- Edward Jenner et la vaccination -- La création des premiers vaccins par Louis Pasteur -- La découverte des toxines : le premier vaccin « moléculaire » -- Elie Metchnikoff et les phagocytes -- Emil Behring et la découverte des anticorps -- Les vaccins idéaux : les anatoxines -- La course aux vaccins contre les grands fléaux -- Le vaccin contre la rougeole -- Éliminer la « paralysie infantile » -- Chapitre 12. « Trembler de peur et de froid » -- Le kuru et Carleton Gagducek -- La découverte des prions par Stanley Prusiner -- Émergence de la maladie des vaches folles -- Quand la maladie des vaches folles passe à l'homme -- Chapitre 13. L'île de la Renaissance -- Une idée vieille comme le monde -- Le dilemme : Dr Jekill et M. Hyde -- L'extermination des lapins -- La guerre de l'empire du Levant -- Porton Down et Fort Detrick -- Biopreparat -- L'Irak de Saddam Hussein -- L'expérience sud-africaine : le Dr Wouter Basson -- Le bioterrorisme -- La grande menace -- Les leçons de l'histoire -- Chapitre 14. Épilogue. Terra incognita -- Les vestiges bactériens -- Les gènes « sauteurs » -- Glossaire -- Bibliographie -- Index.
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The dlt operon of Gram-positive bacteria comprises four genes (dltA, dltB, dltC and dltD) that catalyse the incorporation of D-alanine residues into the cell wall-associated lipoteichoic acids (LTAs). In this work, we characterized the dlt operon of Listeria monocytogenes and constructed a D-Ala-deficient LTA mutant by inactivating the first gene (dltA) of this operon. The DltA− mutant did not show any morphological alterations and its growth rate was similar to that of the wild-type strain. However, it exhibited an increased susceptibility to the cationic peptides colistin, nisin and polymyxin B. The virulence of the DltA− mutant was severely impaired in a mouse infection model (4 log increase in the LD50) and, in vitro, the adherence of the mutant to various cell lines (murine bone marrow-derived macrophages and hepatocytes and a human epithelial cell line) was strongly restricted, although the amounts of surface proteins implicated in virulence (ActA, InlA and InlB) remains unaffected. We suggest that the decreased adherence of the DltA− mutant to non-phagocytic and phagocytic cells might be as a result of the increased electronegativity of its charge surface and/or the presence at the bacterial surface of adhesins possessing altered binding activities. These results show that the D-alanylation of the LTAs contributes to the virulence of the intracellular pathogen L. monocytogenes.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 35 (2000), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Stress proteins play an important role in virulence, yet little is known about the regulation of stress response in pathogens. In the facultative intracellular pathogen Listeria monocytogenes, the Clp ATPases, including ClpC, ClpP and ClpE, are required for stress survival and intracellular growth. The first gene of the clpC operon of L. monocytogenes encodes a homologue of the Bacillus subtilis CtsR repressor of stress response genes. An L. monocytogenes ctsR-deleted mutant displayed enhanced survival under stress conditions (growth in the presence of 2% NaCl or at 42°C), but its level of virulence in the mouse was not affected. The virulence of a wild-type strain constitutively expressing CtsR is significantly attenuated, presumably because of repression of the stress response. Regulation of the L. monocytogenes clpC, clpP and clpE genes was investigated using transcriptional fusions in B. subtilis as a host. The L. monocytogenes ctsR gene was placed under the control of an inducible promoter, and regulation by CtsR and heat shock was demonstrated in vivo in B. subtilis. The purified CtsR protein of L. monocytogenes binds specifically to the clpC, clpP and clpE regulatory regions, and the extent of the CtsR binding sites was defined by DNase I footprinting. Our results demonstrate that this human pathogen possesses a CtsR regulon controlling class III heat shock genes, strikingly similar to that of the saprophyte B. subtilis. This is the first description of a stress response regulatory gene in a pathogen.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Listeriolysin O (LLO) is a pore-forming cytolysin secreted by the pathogen Listeria monocytogenes and is required for its intracellular survival. We recently demonstrated that in endothelial cells, LLO activates the NF-κB signalling pathway. In this work, we studied the LLO-induced molecular cascade of NF-κB activation with a cellular model extensively used to analyse the signalling pathway of NF-κB activation, i.e. the human embryonic kidney HEK-293 cell line and its derivatives (transfectants or mutants). When the stably transfected derivative HEK-293 cells expressing IL-1RI were exposed to LLO, a strong NF-κB activation was detected, contrasting with other cell lines (HEK-293 wild type, HEK-293.T and COS) expressing a very low level of IL-1RI. Although a delayed kinetics of LLO-dependent NF-κB activation suggests an autocrine or paracrine IL-1-dependent pathway, we found that LLO-dependent NF-κB activation did not require the IL-1 protein synthesis nor the interaction with the IL-1RI specific receptor. Herein, we demonstrated that LLO-dependent NF-κB activation requires the activation of the IκB kinase β (IKKβ) subunit of IKK complex to phosphorylate and degrade cytoplasmic IκBα, a natural inhibitor of NF-κB. The activation induced by LLO does not require the adapters MyD88 and IL-1R-associated kinase (IRAK). We suggested that LLO induces a distinct signalling pathway from that of IL-1 and its receptor.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We identified the stress-induced ClpP of Listeria monocytogenes and demonstrated its crucial role in intracellular survival of this pathogen. ClpP is a 21.6 kDa protein belonging to a family of proteases highly conserved in prokaryotes and eukaryotes. A clpP-deleted mutant enabled us to demonstrate that ClpP is involved in proteolysis and is required for growth under stress conditions. Intramacrophage survival of this mutant was strongly restricted, thus resulting in loss of virulence for the mouse. The activity of listeriolysin O, a major virulence factor implicated in bacterial escape from phagosomes of macrophages, was much reduced in the clpP mutant under stress conditions. Direct evidence for the role of ClpP in the intracellular parasitism was obtained by showing that virulence and haemolytic activity were fully restored by complementation of the mutant. These results suggest that ClpP is involved in the rapid adaptive response of intracellular pathogens during the infectious process.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd.
    Molecular microbiology 44 (2002), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The integrity of the genetic material of bacteria is guaranteed by a set of distinct repair mechanisms. The participation of these repair systems in bacterial pathogenicity has been addressed only recently. Here, we study for the first time the participation in virulence of the MutSL mismatch repair system of Listeria monocytogenes. The mutS and mutL genes, which are contiguous in the L. monocytogenes chromosome, were identified after in silico analysis. The deduced MutS shares 62% identity with MutS of Bacillus subtilis and 50% identity with HexA, its homologue in Streptococcus pneumoniae; MutL shares 59% identity with MutL of B. subtilis and 47% identity with HexB of S. pneumoniae. Functional analysis of the mutSL locus was studied by constructing a double knock-out mutant. We showed that the deletion ΔmutSL induces: (i) a 100- to 1000-fold increase in the spontaneous mutation rate; and (ii) a 10- to 15-fold increase in the frequency of transduction, thus demonstrating the role of mutSL of L. monocytogenes in both mismatch repair and homologous recombination. We found that the deletion ΔmutSL moderately affected bacterial virulence, with a 1-log increase in the lethal dose 50% (LD50) in the mouse. Strikingly, repeated passages of the mutant strain in mice reduced virulence further. Competition assays between wild-type and mutant strains showed that the deletion ΔmutSL reduced the capacity of L. monocytogenes to survive and multiply in mice. These results thus demonstrate that, for the intracellular pathogen L. monocytogenes, a hypermutator phenotype is more deleterious than profitable to its virulence.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Adherence of pathogenic microorganisms to the cell surface is a key event during infection. We have previously reported the characterization of Listeria monocytogenes transposon mutants defective in adhesion to eukaryotic cells. One of these mutants had lost the ability to produce Ami, a 102 kDa autolytic amidase with an N-terminal catalytic domain and a C-terminal cell wall-anchoring domain made up of repeated modules containing the dipeptide GW (‘GW modules’). We generated ami null mutations by plasmid insertion into L. monocytogenes strains lacking the invasion proteins InlA (EGDΔinlA), InlB (EGDΔinlB) or both (EGDΔinlAB). These mutants were 5–10 times less adherent than their parental strains in various cell types. The adhesion capacity of the mutants was restored by complementation with a DNA fragment encoding the Ami cell wall-anchoring domain fused to the Ami signal peptide. The cell-binding activity of the Ami cell wall-anchoring domain was further demonstrated using the purified polypeptide. Growth of the ami null mutants constructed in EGD and EGDΔinlAB backgrounds was attenuated in the livers of mice inoculated intravenously, indicating a role for Ami in L. monocytogenes virulence. Adhesive properties have recently been reported in the non-catalytic domain of two other autolysins, Staphylococcus epidermidis AtlE and Staphylococcus saprophyticus Aas. Interestingly, we found that these domains were also composed of repeated GW modules. Thus, certain autolysins appear to promote bacterial attachment by means of their GW repeat domains. These molecules may contribute to the colonization of host tissues by Gram-positive bacteria.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The hly-encoded listeriolysin O (LLO) is a major virulence factor secreted by the intracellular pathogen Listeria monocytogenes, which plays a crucial role in the escape of bacteria from the phagosomal compartment. Here, we identify a putative PEST sequence close to the N-terminus of LLO and focus on the role of this motif in the biological activities of LLO. Two LLO variants were constructed: a deletion mutant protein, lacking the 19 residues comprising this sequence (residues 32–50), and a recombinant protein of wild-type size, in which all the P, E, S or T residues within this motif have been substituted. The two mutant proteins were fully haemolytic and were secreted in culture supernatants of L. monocytogenes in quantities comparable with that of the wild-type protein. Strikingly, both mutants failed to restore virulence to a hly-negative strain in vivo. In vitro assays showed that L. monocytogenes expressing the LLO deletion mutant was strongly impaired in its ability to escape from the phagosomal vacuole and, subsequently, to divide in the cytosol of infected cells. This work reveals for the first time that the N-terminal portion of LLO plays an important role in the development of the infectious process of L. monocytogenes.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: A putative PEST sequence was recently identified close to the N-terminus of listeriolysin O (LLO), a major virulence factor secreted by the pathogenic Listeria monocytogenes. The deletion of this motif did not affect the secretion and haemolytic activity of LLO, but abolished bacterial virulence. Here, we first tested whether the replacement of the PEST motif of LLO by two different sequences, with either a very high or no PEST score, would affect phagosomal escape, protein stability and, ultimately, the virulence of L. monocytogenes. Then, we constructed LLO mutants with an intact PEST sequence but carrying mutations on either side, or on both sides, of the PEST motif. The properties of these mutants prompted us to construct three LLO mutants carrying single amino acid substitutions in the distal portion of the PEST region (P49A, K50A and P52A; preprotein numbering). Our data demonstrate that the susceptibility of LLO to intracellular proteolytic degradation is not related to the presence of a high PEST score sequence and that the insertion of two residues immediately downstream of the intact PEST sequence is sufficient to impair phagosomal escape and abolish bacterial virulence. Furthermore, we show that single amino acid substitutions in the distal portion of the PEST motif are sufficient to attenuate bacterial ­virulence significantly, unravelling the critical role of this region of LLO in the pathogenesis of L. ­monocytogenes.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The facultative intracellular bacterium Listeria monocytogenes is an invasive pathogen that crosses the vascular endothelium and disseminates to the placenta and the central nervous system. Its interaction with endothelial cells is crucial for the pathogenesis of listeriosis. By infecting in vitro human umbilical vein endothelial cells (HUVEC) with L. monocytogenes, we found that wild-type bacteria induced the expression of the adhesion molecules (ICAM-1 and E-selectin), chemokine secretion (IL-8 and monocyte chemotactic protein-1) and NF-κB nuclear translocation. The activation of HUVEC required viable bacteria and was abolished in prfA-deficient mutants of L. monocytogenes, suggesting that virulence genes are associated with endothelial cell activation. Using a genetic approach with mutants of virulence genes, we found that listeriolysin O (LLO)-deficient mutants inactivated in the hly gene did not induce HUVEC activation, as opposed to mutants inactivated in the other virulence genes. Adhesion molecule expression, chemokine secretion and NF-κB activation were fully restored by a strain of Listeria innocua transformed with the hly gene encoding LLO. The relevance in vivo of endothelial cell activation for listerial pathogenesis was investigated in transgenic mice carrying an NF-κB-responsive lacZ reporter gene. NF-κB activation was visualized by a strong lacZ expression in endothelial cells of capillaries of mice infected with a virulent haemolytic strain, but was not seen in those infected with a non-haemolytic isogenic mutant. Direct evidence that LLO is involved in NF-κB activation in transgenic mice was provided by injecting intravenously purified LLO, thus inducing stimulation of NF-κB in endothelial cells of blood capillaries. Our results demonstrate that functional listeriolysin O secreted by bacteria contributes as a potent inflammatory stimulus to inducing endothelial cell activation during the infectious process.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...