title: In vitro cultivation of an insect Microsporidian Tubulinosema ratisbonensis in mammalian cells.
abstract: Tubulinosema ratisbonensis is a microsporidian pathogen of Drosophila melanogaster belonging to the family Tubulinosematidae. The microsporidia in this family mainly cause infections in invertebrate hosts, but two members of this family, Brachiola vesicularum and Brachiola algerae, have been found to cause infections in humans as well. Moreover, B. algerae can be transmitted to immunodeficient mice and grows in mammalian cell cultures. Thus, the examination of the opportunistic properties of other members of the family Tubulinosematidae is important. Spores of T. ratisbonensis, isolated from infected fruit flies, were used to inoculate mammalian and insect cell cultures. Parasite growth was only seen in human lung fibroblasts. No growth was seen in Vero cells or insect cell cultures. Comparison of growth kinetics at 31 degrees C and 37 degrees C showed that there were fewer and smaller parasitic foci in cultures incubated at 37 degrees C. Transmission electron microscopy revealed the typical ultrastructure of T. ratisbonensis, and scanning electron microscopy showed oval or slightly pyriform spores, with some spores having extruded their polar tubes. The PCR-amplified sequences of rDNA fragments from infected cell cultures were 100% identical to the original T. ratisbonensis rRNA sequence. As T. ratisbonensis is able to proliferate in mammalian cell cultures, it may have the opportunistic properties of other members of the family Tubulinosematidae.
authors: Klinik und Poliklinik für Innere Medizin I, Universität Regensburg, 93042 Regensburg, Germany.
authors: Caspar
authors: C
authors: Franzen
authors: Susanne
authors: S
authors: Fischer
authors: Josef
authors: J
authors: Schroeder
authors: Wilfrid
authors: W
authors: Bleiss
authors: Stephan
authors: S
authors: Schneuwly
authors: Jürgen
authors: J
authors: Schölmerich
authors: Bernd
authors: B
authors: Salzberger
mesh_terms: D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005347:Fibroblasts; D006801:Humans; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008858:Microscopy, Phase-Contrast; D016814:Microsporidia / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014709:Vero Cells
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal