[The morphofunctional characteristics of the ultrastructure of the outer membrane of opisthorchid eggs. 1. The hatching of miracidia].

Some functional peculiarities of miracidia hatching from O. felineus eggs have been studied, using scanning electron microscope. The results were compared to the earlier data obtained by the method elaborated for the determination of opisthorchis eggs viability by stimulation of miracidia release in the artificial media. It is concluded that in the course of miracidia hatching the two release-stimulating factors (mechanical and chemical) are mutually complementing each other. First, the egg membrane is deformed, in which the radula of the mollusk host plays an essential role, then the process of chemical activation of the hatching gland is triggered and miracidia motor activity is stimulated. A complex comb-shaped structure of opisthorchis eggs outer membranes is associated with the necessity of long-term eggs survival in the water reservoirs and forms a light delicate carcass preventing the egg from deformation.