Fine structure of buccal cavity and esophagus in Toxocara canis (Nematoda, Ascarididae) infective larvae.
The ultrastructure of the alimentary tract of Toxocara canis infective larvae, with emphasis on the buccal cavity and vestibular-esophageal region, is described. The buccal opening which extends to the vestibule is lined by a thick cuticle. Between the buccal opening and the vestibule there are three cuticular projections which might function either as a valve or for grinding food. Cells associated with the triradiate vestibule show an elaborate system of narrowed cytoplasmic lamellae differentiated in the apical part of the cells. The possible osmoregulatory function of these cells is discussed. Active secretory gland cells are present in the esophagus: the dorsal gland is located behind the muscular esophageal tract, the others are placed at the posterior region of the esophagus. They have an intracytoplasmic cistern which opens through a secretory duct into the esophageal lumen. The secretion produced by these cells might be used to facilitate the migration of the larva; it could represent the material with antigenic properties.
Talluri
M V
MV
Department of Evolutionary Biology, University of Siena, Italy.
Paggi
L
L
Orecchia
P
P
Dallai
R
R
D000818:Animals; D004285:Dogs; D004947:Esophagus / Q000648:ultrastructure; D007814:Larva; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009055:Mouth / Q000648:ultrastructure; D014119:Toxocara / Q000302:isolation & purification / Q000648:ultrastructure*