1. Laboratory of Molecular Parasitology, Institute for Molecular Biology and Medicine, Université Libre de Bruxelles, 12 rue des Profs Jeener et Brachet, B6041 Gosselies, Belgium.
2. Department of Medical Biochemistry, University of Aarhus, DK-8000 Aarhus, Denmark.
3. Unit of Cellular Biochemistry and Biology, University of Namur, B5000 Namur, Belgium.