title: Ultrastructural analysis of the freeze-etched spore envelope of the microsporidian, Nosema apis Zander.
abstract: The outer limiting layer of the spore coat of Nosema apis is relatively smooth. The inner limiting layer shows two fractured faces, the concave face carrying many stud-like projections, 120 nm long and 50 nm high, while the convex face carries numerous depressions which are complementary to the projections. In addition, the convex face bears 7 nm particles. In between the outer and inner limiting layers lies the thick homogeneous portion of spore coat which is comprised of numerous microfibres, each 9 nm in diameter. These microfibres resemble those in the freeze-etched host endocuticle. Next to the inner limiting layer of the spore coat are double spore membranes. The convex faces of these spore membranes have a dense population of particles, each 7 nm in diameter.
mesh_terms: D000818:Animals; D016782:Apicomplexa / Q000648:ultrastructure*; D005613:Freeze Etching; D008566:Membranes / Q000648:ultrastructure; D013170:Spores / Q000648:ultrastructure