title: Polyoxin D inhibits colloidal gold-wheat germ agglutinin labelling of chitin in dimorphic forms of Candida albicans.
abstract: Yeasts and mycelia of the pathogen Candida albicans grown in the presence of polyoxin D, a competitive inhibitor of chitin synthase, formed chains of swollen bulbous cells as observed by fluorescence microscopy. Wheat germ agglutinin (WGA) complexed to colloidal gold (Au) was used as a specific label at the ultrastructural level to visualize chitin in walls of control and polyoxin-treated cells. In control cells, Au-WGA labelling was preferentially localized in the innermost wall layers and was predominant at bud scars and septa. After 4.5 h in 4 mM-polyoxin D, budding in yeasts and lateral wall growth in mycelia continued, but primary septa failed to form and no Au-WGA labelling was detected in the walls. These results demonstrated that the morphological alterations caused by polyoxin D were due to the absence of chitin, a wall component important for formation of primary septa and for maintenance of structural integrity during morphogenesis.
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects* / Q000648:ultrastructure; D002473:Cell Wall / Q000648:ultrastructure; D002686:Chitin / Q000378:metabolism*; D006046:Gold; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D011741:Pyrimidine Nucleosides / Q000494:pharmacology; D014909:Wheat Germ Agglutinins
chemical_list: D000935:Antifungal Agents; D011741:Pyrimidine Nucleosides; D014909:Wheat Germ Agglutinins; D002686:Chitin; D006046:Gold; C002458:polyoxorim