Voici les éléments 1 - 10 sur 31
- PublicationAccès libreRole of soil macrofauna in P cycling(NY, USA: Springer, 2011)
;Chapuis-Lardy, L ; ; ;Lopez-Hernandez, D ;Blanchard, E ;Bünemann, E.K ;Oberson, AFrossard, E
- PublicationAccès libre
- PublicationMétadonnées seulementDoes access to the bluestreak cleaner wrasse Labroides dimidiatus affect indicators of stress and health in resident reef fishes in the Red Sea?(2011)
; ;Lusa, Jeanne ;Meyer, Meghann ;Soares, Marta ;Oliveira, Rui F. ;
- PublicationMétadonnées seulementEstimated Lyme borreliosis incidence in the canton of Neuchâtel (Switzerland)(2012-1-1)
;Moosmann, Y. ; ;
- PublicationAccès libreRole of Soil Macrofauna in Phosphorus Cycling(2011)
;Chapuis-Lardy, Lydie ; ; ;López-Hernández, DaniloBlanchart, Eric
- PublicationAccès libreIdentification of an Ixodes ricinus salivary gland fraction through its ability to stimulate CD4 T cells present in BALB/c mice lymph nodes draining the tick fixation site(1997)
;Ganapamo, F. ;Rutti, BernardBALB/c mice infested with larvae or nymphs of Ixodes ricinus develop in their lymph nodes a T cell-specific immune response triggered by salivary gland soluble antigens (SGA). SGA are apparently conserved in the 3 biological stages of I. ricinus ticks and are species specific. SGA derived from partially fed females I. ricinus stimulate lymph node T cells from mice infested with I. ricinus larvae or nymphs. In contrast, lymph node cells from mice infested with Amblyomma hebraeum nymphs do not respond. A chromatographic fraction enriched with a 65 kDa protein (IrSG65) isolated from salivary glands of I. ricinus partially fed females induces in vitro a specific T cell proliferation of lymph node cells from mice infested with I. ricinus nymphs. The depletion of CD4+ T cells drastically reduces the ability of lymphocytes from infested mice to proliferate after IrSG65 stimulation.
- PublicationAccès libreIxodes ricinus L. : mast cells, basophils and eosinophils in the sequence of cellular events in the skin of infested or re-infested rabbits(1982)
;Fivaz, V.Some information on acquired resistance of rabbits against Ixodes ricinus ticks has been obtained by comparing tissue changes and cellular infiltration during 2 successive infestations, with particular emphasis on the cells involved in immediate type hypersensitivity reactions: mast cells, basophils and eosinophils. More degranulated mast cells were observed in tick lesions 2 h after the beginning of re-infestation than in the first infestation and more degranulated basophils were present on the 5th day of re-infestation. Numerous eosinophils infiltrated the dermis, especially on the 5th day of the second infestation.
- PublicationAccès libreIxodes ricinus Tick Lipocalins: Identification, Cloning, Phylogenetic Analysis and Biochemical Characterization(2008)
;Beaufays, Jérôme ;Adam, Benoît ;Decrem, Yves ;Prévôt, Pierre-Paul ;Santini, Sébastien ;Brasseur, Robert ; ;Lins, Laurence ;Vanhamme, LucGodfroid, EdmondBackground : During their blood meal, ticks secrete a wide variety of proteins that interfere with their host's defense mechanisms. Among these proteins, lipocalins play a major role in the modulation of the inflammatory response.
Methodology/Principal Findings : Screening a cDNA library in association with RT-PCR and RACE methodologies allowed us to identify 14 new lipocalin genes in the salivary glands of the Ixodes ricinus hard tick. A computational in-depth structural analysis confirmed that LIRs belong to the lipocalin family. These proteins were called LIR for “Lipocalin from I. ricinus” and numbered from 1 to 14 (LIR1 to LIR14). According to their percentage identity/similarity, LIR proteins may be assigned to 6 distinct phylogenetic groups. The mature proteins have calculated pM and pI varying from 21.8 kDa to 37.2 kDa and from 4.45 to 9.57 respectively. In a western blot analysis, all recombinant LIRs appeared as a series of thin bands at 50–70 kDa, suggesting extensive glycosylation, which was experimentally confirmed by treatment with N-glycosidase F. In addition, the in vivo expression analysis of LIRs in I. ricinus, examined by RT-PCR, showed homogeneous expression profiles for certain phylogenetic groups and relatively heterogeneous profiles for other groups. Finally, we demonstrated that LIR6 codes for a protein that specifically binds leukotriene B4.
Conclusions/Significance : This work confirms that, regarding their biochemical properties, expression profile, and sequence signature, lipocalins in Ixodes hard tick genus, and more specifically in the Ixodes ricinus species, are segregated into distinct phylogenetic groups suggesting potential distinct function. This was particularly demonstrated by the ability of LIR6 to scavenge leukotriene B4. The other LIRs did not bind any of the ligands tested, such as 5-hydroxytryptamine, ADP, norepinephrine, platelet activating factor, prostaglandins D2 and E2, and finally leukotrienes B4 and C4.
- PublicationAccès libreCytokines (IL-4 and IFN-γ) and antibodies (IgE and IgG2a) produced in mice infected with Borrelia burgdorferi sensu stricto via nymphs of Ixodes ricinus ticks or syringe inoculations(2000)
;Christe, Martine ;Rutti, BernardMice were tolerant to tick bites during three infestations with nymphs of Ixodes ricinus infected with Borrelia burgdorferi sensu stricto. To determine whether tick bites influence the immune response against B. burgdorferi, we examined the production of cytokines IL-4 and IFN-γ by lymph node cells of BALB/c mice and IL-4 deficient BALB/c mice after tick inoculation versus syringe inoculation of B. burgdorferi. We also measured IgG2a anti-borrelial antibodies and total IgE in these mice. Results showed that BALB/c mice developed a Th2 immune response against B. burgdorferi after tick inoculation and a mixed Th1/Th2 response after syringe inoculation of B. burgdorferi. IL-4 deficient mice produced a Th1 immune response in both cases. IL-4 produced following tick bites greatly decreased the production of anti-borrelial IgG2a antibodies by comparison with the production of anti-borrelial IgG2a antibodies produced following syringe injection of B. burgdorferi.
- PublicationAccès libreIsolation of Ixodes ricinus salivary gland mRNA encoding factors induced during blood feeding(2002)
;Leboulle, Gérard ;Rochez, Candice ;Louahed, Jamila ;Rutti, Bernard ; ;Bollen, AlexGodfroid, EdmondIn tick salivary glands, genes induced during blood feeding result in the expression of new proteins secreted into tick saliva. These proteins are potentially involved in modulation of vertebrate host immune and hemostatic responses. In this study, subtractive and full-length cDNA libraries were constructed by use of mRNA extracted from salivary glands of unfed and 5-day engorged Ixodes ricinus. Sequences from these 2 libraries were compared with European Molecular Biology Laboratory (EMBL)/GenBank databases, which led to their classification into 2 major groups. The first group comprises cDNAs that failed to match or showed low homology to genes of known function. The second group includes sequences that showed high homology to genes of known function--for example, anticoagulants, inhibitors of platelet aggregation, and immunomodulatory proteins. Analyses of corresponding proteins suggest that they may be secreted by salivary gland cells. To study the properties of the recombinant proteins, selected cDNAs were expressed in mammalian or bacterial systems.