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- Appelgren, A., et al.
(författare)
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Relative fitness of a generalist parasite on two alternative hosts : a cross-infestation experiment to test host specialization of the hen flea Ceratophyllus gallinae (Schrank)
- 2016
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 29:5, s. 1091-1101
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Tidskriftsartikel (refereegranskat)abstract
- Host range is a key element of a parasite's ecology and evolution and can vary greatly depending on spatial scale. Generalist parasites frequently show local population structure in relation to alternative sympatric hosts (i.e. host races) and may thus be specialists at local scales. Here, we investigated local population specialization of a common avian nest-based parasite, the hen flea Ceratophyllus gallinae (Schrank), exploiting two abundant host species that share the same breeding sites, the great tit Parus major (Linnaeus) and the collared flycatcher Ficedula albicollis (Temminck). We performed a cross-infestation experiment of fleas between the two host species in two distinct study areas during a single breeding season and recorded the reproductive success of both hosts and parasites. In the following year, hosts were monitored again to assess the long-term impact of cross-infestation. Our results partly support the local specialization hypothesis: in great tit nests, tit fleas caused higher damage to their hosts than flycatcher fleas, and in collared flycatcher nests, flycatcher fleas had a faster larval development rates than tit fleas. However, these results were significant in only one of the two studied areas, suggesting that the location and history of the host population can modulate the specialization process. Caution is therefore called for when interpreting single location studies. More generally, our results emphasize the need to explicitly account for host diversity in order to understand the population ecology and evolutionary trajectory of generalist parasites.
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- Appelgren, Daniel, et al.
(författare)
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Active NET formation in Libman–Sacks endocarditis without antiphospholipid antibodies : A dramatic onset of systemic lupus erythematosus
- 2018
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Ingår i: Autoimmunity. - : Informa UK Limited. - 0891-6934 .- 1607-842X. ; 51:6, s. 310-318
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Tidskriftsartikel (refereegranskat)abstract
- Although neutrophil extracellular traps (NETs) have been highlighted in several systemic inflammatory diseases, their clinical correlates and potential pathological role remain obscure. Herein, we describe a dramatic onset of systemic lupus erythematosus (SLE) with clear-cut pathogenic implications for neutrophils and NET formation in a young woman with cardiac (Libman–Sacks endocarditis) and central nervous system (psychosis and seizures) involvement. Despite extensive search, circulating antiphospholipid autoantibodies, a hallmark of Libman–Sacks endocarditis, could not be detected. Instead, we observed active NET formation in the tissue of the mitral valve, as well as in the circulation. Levels of NET remnants were significantly higher in serially obtained sera from the patient compared with sex-matched blood donors (p =.0011), and showed a non-significant but substantial correlation with blood neutrophil counts (r = 0.65, p =.16). The specific neutrophil elastase activity measured in serum seemed to be modulated by the provided immunosuppressive treatment. In addition, we found anti-Ro60/SSA antibodies in the cerebrospinal fluid of the patient but not NET remnants or increased elastase activity. This case illustrates that different disease mechanisms mediated via autoantibodies can occur simultaneously in SLE. NET formation with release of cytotoxic NET remnants is a candidate player in the pathogenesis of this non-canonical form of Libman–Sacks endocarditis occurring in the absence of traditional antiphospholipid autoantibodies. The case description includes longitudinal results with clinical follow-up data and a discussion of the potential roles of NETs in SLE.
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