Intraocular microsporidiosis due to Encephalitozoon cuniculi in a patient with idiopathic CD4+ T-lymphocytopenia

Encephalitozoon cuniculi was documented to cause disseminated microsporidial infection including an iris tumor and endophthalmitis in an adolescent with idiopathic CD4+ T-lymphocytopenia. The diagnosis was established by microscopic, serologic and molecular methods. E. cuniculi (rabbit strain) was identified from the iris tumor, as well as from urine, conjunctival, corneal, and nasal swabs. Treatment with oral albendazole led to rapid improvement. This case raises the possibility of disseminated microsporidial infection in the context of idiopathic CD4+ T-lymphocytopenia and possibly advanced human immunodeficiency virus (HIV) infection, and above all the possibility of intraocular infection with E. cuniculi in humans.

Phagocytic uptake of Encephalitozoon cuniculi by nonprofessional phagocytes

Encephalitozoon cuniculi is an obligate intracellular, spore-forming parasite belonging to the microsporidia that can cause disseminated infection in immunocompromised persons. E. cuniculi spores infect host cells by germination, i.e., by explosively everting the polar filament, through which the spore contents (sporoplasms) are subsequently injected into the cytoplasm. In addition, we observed intracellular, nongerminated spores in various nonprofessional phagocytes. In MRC5 cells, the number of internalized spores was approximately 10-fold higher than the number of injected sporoplasms. Compared to the rate of uptake by human monocyte-derived macrophages, internalization rates by A549 cells, MRC5 cells, and 293 cells were 0.6, 4.4, and 22.2%, respectively. The mechanism of uptake was studied in MRC5 cells. Killed spores were internalized at the same rate as live spores, indicating that nongerminated parasites do not actively participate in cell entry. Cytochalasin D inhibited uptake of spores by 95%, demonstrating an actin-dependent process. By electron and epifluorescence microscopy, intracellular spores were found in a tightly fitting membrane-bound compartment. The vacuole containing the spores was positive for the lysosomal membrane protein LAMP-1 and colocalized with the late endosomal-lysosomal content marker rhodamine dextran. Our results show that, in addition to the unique way in which microsporidia infect cells, E. cuniculi spores enter nonprofessional phagocytes by phagocytosis and traffic into a late endosomal-lysosomal compartment.

Helle Skulptur vor opak dunklem Hintergrund. Entstehung und Funktion eines Bildcodes

(Frühe Skulpturfotografie) Der opak dunkle Hintergrund gehört spätestens seit der Einführung der Negativretusche und deren massenhaften Anwendung durch die grossen fotografischen Kunstverlage in den 1860er Jahren bis teilweise in die 1920er Jahre oder darüber hinaus bei Fotografien antiker Skulpturen aus hellem Material zu den Standards. Trotz der Wucht dieses meist grafischen Eingriffs ins Bild durch Retusche wird der uniforme Hintergrundersatz auch in jüngster Zeit noch als den Hintergrund neutralisierend beschrieben. Die Entkontextualisierung der mehrheitlich in den berühmten italienischen Museen in Florenz, Rom und Neapel fotografierten Skulpturen aus ihrer ursprünglichen Räumlichkeit des Aufstellungskontextes führt die Skulptur medienbedingt jedoch nicht in die Hintergrundlosigkeit. In welche neue Kontexte wird die Skulptur durch diesen opak dunklen Hintergrund jedoch transportiert? In meinem Vortrag gehe ich Fragen der Entstehung und Funktion des opak dunklen Hintergrundes in der seriellen Skulpturfotografie einzeln abgelichteter Skulpturen der grossen fotografischen Kunstverlage Italiens (Alinari, Anderson, Brogi, ...) im 19. Jahrhundert nach und beleuchte das Phänomen dieser Hintergründe unter medien-, produktions- und technikästhetischen Aspekten.