title: Ultrastructural and physiological changes occurring upon germination and outgrowth of Azotobacter vinelandii cysts.
abstract: Dormant cysts of Azotobacter vinelandii germinated at 30 degrees C in Burk nitrogen-free media containing 1% glucose. Samples taken at intervals and examined by electron microscopy revealed that as germination progressed, vesicle-like and fibrillar structures became visible in the intine region. Lamellae associated with the cell membrane appeared in the central body at 6 h post-initiation of germination. Both electron micrographic and chemical analysis showed that the poly-beta-hydroxybutyrate content of cysts decreased significantly after 4 h of germination. Dormant cysts were resistant to sonic oscillation, but this property was lost during their conversion to metabolically active vegetative cells.
mesh_terms: D001395:Azotobacter / Q000502:physiology* / Q000648:ultrastructure; D002462:Cell Membrane / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D006885:Hydroxybutyrates / Q000032:analysis / Q000378:metabolism; D014617:Vacuoles / Q000648:ultrastructure
chemical_list: D006885:Hydroxybutyrates