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Pfister, Kurt

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Pfister, Kurt
Affiliation principale
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https://libra.unine.ch/handle/123456789/345

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  • Publication
    Accès libre
    Protein expression profile of Gasterophilus intestinalis larvae causing horse gastric myiasis and characterization of horse immune reaction
    (2009)
    Roelfstra, Liselore
    ;
    Deeg, Cornelia A.
    ;
    Hauck, Stefanie M.
    ;
    Buse, Christina
    ;
    Membrez, Mathieu
    ;
    Betschart, Bruno 
    ;
    Pfister, Kurt 
    Background Little information is available on the immunological aspect of parasitic Gasterophilus intestinalis (Diptera, Oestridae) larvae causing horse gastric myiasis. The objectives of this research were to analyze the protein content of larval crude extracts of the migrating second and third larvae (L2 and L3) of G. intestinalis in order to characterize the immune response of horses.
    Results The proteomic profile of L2 and L3, investigated by using one and two dimensional approaches, revealed a migration pattern specific to each larval stage. Furthermore, Western blots were performed with horse sera and with sera of Balb/c mice immunised with the larval crude extracts of L2 or L3, revealing a different immune reaction in naturally infected horses vs. artificially induced immune reaction in mice. The comparisons of the immunoblot profiles demonstrate that the stage L2 is more immunogenic than the stage L3 most likely as an effect of the highest enzymatic production of L2 while migrating through the host tissues. Fifteen proteins were identified by mass spectrometry.
    Conclusion This work provides further information into the understanding of the interaction between G. intestinalis and their host and by contributing a novel scheme of the proteomic profile of the main larval stages.
  • Publication
    Accès libre
    PCR Detection and Serological Evidence of Granulocytic Ehrlichial Infection in Roe Deer (Capreolus capreolus) and Chamois (Rupicapra rupicapra)
    (2002)
    Liz, Jorge S.
    ;
    Sumner, John W.
    ;
    Pfister, Kurt 
    ;
    Brossard, Michel 
    The role of wild mammals, such as roe deer (Capreolus capreolus) and chamois (Rupicapra rupicapra), in the epidemiology of granulocytic ehrlichiae in Switzerland was investigated. We tested blood samples for Ehrlichia phagocytophila genogroup 16S rRNA gene sequences by PCR and for immunoglobulin G antibodies against granulocytic ehrlichiae by indirect fluorescent-antibody assay (IFA). Overall means of 60.9% of 133 roe deer serum samples and 28.2% of 39 chamois serum samples were seroreactive by IFA. PCR results were positive for 18.4% of 103 roe deer serum samples as well. None of the 24 chamois blood samples tested were positive by PCR. Partial 16S rRNA gene and groESL heat shock operon sequences of three roe deer samples tested showed strong degrees of homology (99.7 and 98.6%, respectively) with the sequences of granulocytic ehrlichiae isolated from humans. These results confirm that chamois, and particularly roe deer, are commonly infected with granulocytic ehrlichiae and provide evidence that these wild mammals are potential reservoirs for granulocytic ehrlichiae in Switzerland.
  • Publication
    Accès libre
    Light and electron microscopy studies of the midgut and salivary glands of second and third instars of the horse stomach bot, Gasterophilus intestinalis
    (2010)
    Roelfstra, Lise-Lore
    ;
    Vlimant, Michèle 
    ;
    Betschart, Bruno 
    ;
    Pfister, Kurt 
    ;
    Diehl, Peter-Allan 
    A morphological study of the midgut and salivary glands of second and third instars of Gasterophilus intestinalis (De Geer) (Diptera: Oestridae) was conducted by light, scanning and transmission electron microscopy. The midgut is anteriorly delimited by a proventriculus, without caeca, and is composed of posterior foregut and anterior midgut tissue from which a double-layered peritrophic matrix is produced. The midgut can be divided into anterior, median and posterior regions on the basis of the structural and physiological variations of the columnar cells which occur along its length. Two other types of cell were identified: regenerative cells scattered throughout the columnar cells, and, more rarely, endocrine cells of two structural types (closed and open). Different secretion mechanisms (merocrine, apocrine and microapocrine) occur along the midgut epithelium. Abundant microorganisms are observed in the endoperitrophic space of the anterior midgut. The origin and nature of these microorganisms remain unknown. No structural differences are observed between the second and third instar midguts. The salivary glands of G. intestinalis second and third instars consist of a pair of elongated tubular structures connected to efferent ducts which unite to form a single deferent duct linked dorsally to the pharynx. Several intermediate cells, without cuticle, make the junction with the salivary gland epithelium layer. Cytological characteristics of the gland epithelial cells demonstrate high cellular activity and some structural variations are noticed between the two larval stages.