title: A freeze-fracture study of the surface of the infective-stage larva of the nematode Trichinella.
abstract: The surface layers of the cuticle of the infective, first-stage larva of the nematodes Trichinella spiralis and T. spiralis var. pseudospiralis have been studied by means of the freeze-fracturing technique. No obvious differences between the two nematodes were found. A double-layered structure covers the cuticle. Its outermost layer consists of particles embedded in an amorphous matrix; its inner layer is composed of a sheet of fine filaments which may be composed of globular subunits. This unique double layered structure is not like a normal cell membrane in structure. The surface of the cuticle beneath it is relatively smooth except for impressions from the inner surface of the double-layered structure. The cuticle surface did not fracture in the manner of a cell membrane.
mesh_terms: D000818:Animals; D005109:Extracellular Matrix / Q000648:ultrastructure; D005614:Freeze Fracturing; D007814:Larva / Q000648:ultrastructure; D008854:Microscopy, Electron; D014234:Trichinella / Q000648:ultrastructure*