title: Intraspecies genotype variability of the microsporidian parasite Encephalitozoon hellem.
abstract: Seven isolates of Encephalitozoon hellem from human immunodeficiency virus-positive patients were genotyped through a series of markers: the internal transcribed spacer (ITS) of ribosomal DNA, the polar tube protein (PTP) gene, and two intergenic spacers (IGS-TH and IGS-HZ) whose polymorphism is newly reported. The genome markers were all analyzed at three levels: PCR amplification followed by polyacrylamide gel electrophoresis, single-strand conformation analysis (SSCA), and DNA sequencing. The polymorphisms detected involve insertions/deletions and point mutations. SSCA can distinguish any pair of sequences, even those differing by a single base pair. The different isolates studied fit into the previously described ITS genotype 1A, except one which seems to be a 2A derivative variant (2D). When PTP and the new markers IGS-TH and IGS-HZ were analyzed, most of the isolates displayed different genotypes, demonstrating that E. hellem has a strong intraspecies variability. A set of markers such as those used here may be very useful in genotyping of clinical samples and in the assessment of epidemiological relationships among E. hellem strains.
authors.affiliation: Departamento de Biología Celular, Bioquímica y Biología Molecular, Facultad de Ciencias Experimentales y de la Salud, Universidad San Pablo-CEU, 28668 Boadilla del Monte, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Haro
authors.forename: Carmen
authors.initials: C
authors.lastname: Del Aguila
authors.forename: Soledad
authors.initials: S
authors.lastname: Fenoy
authors.forename: Nuno
authors.initials: N
authors.lastname: Henriques-Gil
mesh_terms: D000818:Animals; D001483:Base Sequence; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D016819:Encephalitozoon / Q000145:classification / Q000235:genetics*; D005656:Fungal Proteins; D014644:Genetic Variation; D005838:Genotype; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics
chemical_list: D021903:DNA, Ribosomal Spacer; D005656:Fungal Proteins; C116051:PTP protein, Encephalitozoon hellem; D015800:Protozoan Proteins