title: Permeability changes in the egg-shell of hookworms during development and eclosion.
abstract: The development and hatching of Ancylostoma ceylanicum and Ancylostoma tubaeforme eggs in a range of potentially inimical solutions has been examined using time-lapse video micro-recording techniques. In all compounds tested the larvae developed to the active pretzel stage. The inception of activity resulted in an increase in shell permeability to water and small molecules. In anthelmintics of molecular weight (Mr) 400 development continued normally until about the time that control eggs hatched, when there was a marked decrease in larval activity and eclosion did not occur. The addition of a low Mr surface-active agent potentiated the effect of the anthelmintic and caused larval activity to be lost earlier. The calcium inhibitor lanthanum chloride affected larval development rather than eclosion. Large Mr compounds did not affect either development or hatching and the results suggest that the egg-shell may act as a form of sieve, allowing the essential oxygen to reach the developing larva while excluding large potentially dangerous molecules. No appreciable differences were found between the two species of hookworm examined.
mesh_terms: D000165:Acridine Orange / Q000378:metabolism; D000722:Ancylostoma / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D004049:Diethylcarbamazine / Q000494:pharmacology; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D009015:Morantel / Q000494:pharmacology; D010063:Ovum / Q000187:drug effects / Q000378:metabolism; D010539:Permeability; D010879:Piperazines / Q000494:pharmacology; D014743:Videotape Recording
chemical_list: D010879:Piperazines; D009015:Morantel; D000165:Acridine Orange; D004049:Diethylcarbamazine