Authors: Mickaël Riou Christine Koch Dominique Kerboeuf
Publish Date: 2005/01/28
Volume: 95, Issue: 4, Pages: 266-272
Abstract
The embryonation of nematode eggs has been shown to increase their resistance to anthelmintics when parasites are submitted to egg hatch assays Nevertheless no mechanism has been suggested to explain this phenomenon Earlier observations by other authors showed that the biochemical composition of eggshells is altered during the embryonation of eggs The functional consequences of these changes have not been identified We studied the changes in membrane environment eggshells of Haemonchus contortus eggs during the embryonation by fluidity measurements and their effects on nonspecific mechanisms of resistance to anthelmintics We previously demonstrated that these mechanisms imply Pglycoproteins Pgp belonging to the multidrug resistance MDR system and that the Pgp activity is very susceptible to their lipidic environment The results obtained here show that the embryonation induced a significant and gradual increase in eggshell fluidity which was associated with an increased resistance to anthelmintics Differences were observed between H contortus isolates with various levels of resistance which might result from their specific biology and/or membrane composition The membrane environment changes could act both on the solubilization of anthelmintics into the eggs and on the efflux of these lipophilic molecules by PgpThe authors thank Dr Yan Van Wyk Dr Gilles Aumont and Professor Roger Prichard for kindly providing the H contortus isolates Limouzin and his team for the careful maintenance of animals and MarieColette Fauré and her team for their generous help with the bibliography We also thank the “Region Centre” for financing this research The experiments comply with the current French laws on animal experimentation
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