Cycloheximide-induced inhibition of chitin synthesis, and decay of apical vesicles and chitosomes in Phycomyces blakesleeanus.
Addition of cycloheximide rapidly inhibited protein synthesis in Phycomyces blakesleeanus. In contrast, chitin biosynthesis decreased with biphasic kinetics displaying a slow and a rapid decay phases. Electron microscopic studies revealed a decrease in the number of apical vesicles and chitosomes after cycloheximide addition; and no change in wall thickness. It is proposed that the slow phase of decay in chitin biosynthesis represents the exhaustion of the pool of chitosomes which transport the chitin synthase necessary to maintain apical wall growth; whereas the second one corresponds to inactivation of the enzyme, which is short lived in vivo. Data also rule out a change in the polarization of wall synthesis induced by cycloheximide, as suggested in other systems.
Ruiz-Herrera
J
J
Departamento de Ingenieria Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Gto, Mexico. jruiz@irapuato.ira.cinvestav.mx
D000935:Antifungal Agents / Q000494:pharmacology; D002473:Cell Wall / Q000187:drug effects / Q000648:ultrastructure; D002686:Chitin / Q000096:biosynthesis*; D002688:Chitinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology*; D022162:Cytoplasmic Vesicles / Q000187:drug effects* / Q000648:ultrastructure; D005656:Fungal Proteins / Q000032:analysis / Q000187:drug effects; D025301:Hyphae / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D007700:Kinetics; D010800:Phycomyces / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology
D000935:Antifungal Agents; D005656:Fungal Proteins; D011500:Protein Synthesis Inhibitors; D002686:Chitin; D003513:Cycloheximide; D002688:Chitinases