Parasitology



Molecular karyotype diversity in the microsporidian Encephalitozoon cuniculi


C. BIDERRE a1, A. MATHIS a2, P. DEPLAZES a2, R. WEBER a3, G. METENIER a1 and C. P. VIVARES a1c1
a1 Laboratoire de Protistologie Moléculaire et Cellulaire des Parasites Opportunistes, UPESA CNRS 6023, Université Blaise Pascal, 63177 Aubière Cedex, France
a2 Institute of Parasitology, University of Zürich, Winterthurerstrasse 266A, 8057 Zürich, Switzerland
a3 Division of Infectious Diseases, Department of Internal Medicine, University Hospital, Rämiostrasse 100, 8091 Zürich, Switzerland

Abstract

The microsporidian Encephalitozoon cuniculi can infect numerous mammals, including man. Three strains of E. cuniculi have been identified so far, the major marker being the number of a tetranucleotide repeats in the rDNA internal transcribed spacer. We investigated diversity at the chromosomal level through the electrophoretic karyotypes obtained from 15 E. cuniculi isolates from 5 different host species. All preparations provided patterns with 9–12 bands within a narrow molecular size range. Six karyotype forms were distinguished, involving subdivision of strain I into 3 types (A, B, C) and strain II into 2 types (D, E). The types A, B and C were mainly associated with isolates from rabbits of different geographical origins. The types D, E and F were characterized by a reduced chromosome size range, 2 of these appearing specific to a carnivorous host species (D in dog and F in blue fox). Hybridization experiments showed that all E. cuniculi isolates possess 11 chromosomes, with a size polymorphism entailing occasional electrophoretic comigration of heterologous chromosomes and differential migration of homologous ones. DNA rearrangements should occur during mitosis and the hypothesis of diploidy for the basic state of E. cuniculi seems likely.

(Received September 16 1998)
(Revised November 11 1998)
(Accepted November 11 1998)


Key Words: microsporidia; Encephalitozoon cuniculi; molecular karyotype; polymorphism.

Correspondence:
c1 Corresponding author: Laboratoire de Protistologie Moléculaire et Cellulaire des Parasites Opportunistes, UPESA CNRS 6023, Université Blaise Pascal, 63177 Aubière Cedex, France. Tel: +33 4 73 40 74 57. Fax: +33 4 73 40 74 55. E-mail: vivares@cicsun.univ-bpclermont.fr


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