Document 0947
 DOCN  M9440947
 TI    Inhibition of the spore polar filament extrusion of the microsporidium,
       Encephalitozoon hellem, isolated from an AIDS patient.
 DT    9404
 AU    Leitch GJ; He Q; Wallace S; Visvesvara GS; Department of Physiology,
       Morehouse School of Medicine, Atlanta,; Georgia 30310-1495.
 SO    J Eukaryot Microbiol. 1993 Nov-Dec;40(6):711-7. Unique Identifier :
       AIDSLINE MED/94122699
 AB    Spores of the microsporidian parasitic protozoan Encephalitozoon hellem
       were purified and incubated at 37 degrees C in a solution with an
       electrolyte composition similar to that of mammalian extracellular
       fluid, and in solution in which the calcium had been replaced with 0.2
       mM EGTA. Polar filament extrusion (germination) was monitored by both
       scanning electron microscopy and light microscopy. Germination was
       pH-dependent, with optima at pH 7.4 and 9.5, and was significantly
       greater in the presence of medium calcium. Hydrogen peroxide caused a
       concentration-dependent increase in germination that was also reduced in
       a calcium-free medium. Four agents were found to inhibit spontaneous and
       H2O2-stimulated polar filament extrusion: the microfilament disrupter,
       cytochalasin D; the microtubule disrupter, demecolcine; the calcium
       channel blocker, nifedipine; and the antifungal agent, itraconazole.
       These results are consistent with the existence of a
       calcium-channel-mediated step, and requirements for an F-actin- and for
       a tubulin-containing element in the germination process of the spore of
       this parasite. Nifedipine, cytochalasin D and itraconazole all have
       different sites of action and were therefore able to potentiate one
       another when used in paired combination to inhibit germination.
 DE    Animal  Antiprotozoal Agents/*TOXICITY  AIDS-Related Opportunistic
       Infections/*PARASITOLOGY/URINE  Cell Line  Cercopithecus aethiops
       Cytochalasin D/TOXICITY  Demecolcine/TOXICITY  Dose-Response
       Relationship, Drug  Encephalitozoon/DRUG EFFECTS/ISOLATION &
       PURIF/*PHYSIOLOGY  Encephalitozoonosis/*COMPLICATIONS/URINE  Human
       Hydrogen Peroxide/TOXICITY  Hydrogen-Ion Concentration
       Itraconazole/TOXICITY  Microscopy, Electron  Nifedipine/TOXICITY
       Spores/DRUG EFFECTS/ULTRASTRUCTURE  Support, U.S. Gov't, P.H.S.  JOURNAL
       ARTICLE

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