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Institut de biologie
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+41 32 718 30 00
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Rue Emile-Argand 11 (bureaux D013 et D016 - bât. D - rez-de-chaussée)
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Neuchâtel
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CH
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Academic Institute
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Voici les éléments 1 - 10 sur 2558
- PublicationMétadonnées seulementCross-reactive acquired immunity influences transmission success of the Lyme disease pathogen, Borrelia afzelii(2015-12)
; ; ; Cross-reactive acquired immunity in the vertebrate host induces indirect competition between strains of a given pathogen species and is critical for understanding the ecology of mixed infections. In vector-borne diseases, cross-reactive antibodies can reduce pathogen transmission at the vector-to-host and the host-to-vector lifecycle transition. The highly polymorphic, immunodominant, outer surface protein C (OspC) of the tick-borne spirochete bacterium Borrelia afzelii induces a strong antibody response in the vertebrate host. To test how cross-immunity in the vertebrate host influences tick-to-host and host-to-tick transmission, mice were immunized with one of two strain-specific recombinant OspC proteins (A3, A10), challenged via tick bite with one of the two B. afzelii ospC strains (A3, A10), and infested with xenodiagnostic ticks. Immunization with a given rOspC antigen protected mice against homologous strains carrying the same major ospC group allele but provided little or no cross-protection against heterologous strains carrying a different major ospC group allele. There were cross-immunity effects on the tick spirochete load but not on the probability of host-to-tick transmission. The spirochete load in ticks that had fed on mice with cross-immune experience was reduced by a factor of two compared to ticks that had fed on naive control mice. In addition, strain-specific differences in mouse spirochete load, host-to-tick transmission, tick spirochete load, and the OspC-specific IgG response revealed the mechanisms that determine variation in transmission success between strains of B. afzelii. This study shows that cross-immunity in infected vertebrate hosts can reduce pathogen load in the arthropod vector with potential consequences for vector-to-host pathogen transmission. (C) 2015 Elsevier B.V. All rights reserved. - PublicationMétadonnées seulementAcquired resistance in Arabidopsis thaliana(1992)
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- PublicationMétadonnées seulementSelection of Grifola frondosa and Fomitopsis pinicola strains resistant to Trichoderma viride in teflon tubes confrontation method(2004)
; Hmamda, Abdelaziz - PublicationMétadonnées seulementProtozoan and bacterial pathogens in tick salivary glands in wild and domestic animal environments in South Africa(2014)
- PublicationMétadonnées seulementAntennal electrophysiological responses of three parasitic wasps to caterpillar-induced volatiles from maize (Zea mays mays), cotton (Gossypium herbaceum), and cowpea (Vigna unguiculata)(2005)
; - PublicationMétadonnées seulementA global analysis of elevational gradients in leaf herbivory and its underlying drivers: effects of plant growth form, leaf habit, and climatic correlates(2017-9-16)
; Moreira, Xoaquin - PublicationMétadonnées seulement
- PublicationMétadonnées seulementAn experimental study on the influence of tick infestations on nestling performance in great tits (Parus major)(2008)
; Richner, HeinzParasite defense is costly, and the detrimental effects of parasites, which call be measured in terms of parasite virulence, are thought to be influenced by the resources available to the host and, ultimately, by environmental conditions. Hence, if conditions are good, hosts call tolerate a certain number of parasites without suffering severe effects. In addition, the presence of other, parasites call influence the virulence of a focal parasite either positively or negatively. We tested whether an experimental tick infestation reduced nestling performance in Great Tits (Parus major) and whether the effect was altered by a maternal response induced by Hell Fleas (Ceratophyllus gallinae) that is known to protect nestlings against flea infestations (i.e., we tested whether one parasite call alter the virulence of another parasite across [lost generations). We induced the maternal effect by experimentally infesting half the birds' nests with fleas during egg laying. After hatching, nestlings were cross-fostered into broods that then contained both nestlings with and without the maternal effect. Half of these broods were infested with five tick larvae per nestling. This resulted in tick infestation levels similar to levels found in natural populations. The tick infestation did not affect nestling mass, tarsus length, or time until fledging. Thus, all effect of the flea-induced maternal effect on tick virulence was not detectable. From these results, we concluded that either tick larvae do not affect nestlings, or nestlings or their parents can compensate for the negative consequences of tick infestations in numbers similar to those that occur in nature. Received 18 October 2007 accepted 11 April 2008.