Identification of cDNAs induced by the organophosphate trichlorphon in the parasitic copepod Lepeophtheirus salmonis (Copepoda; Caligidae)

Lepeophtheirus salmonis is a copepod ectoparasite of wild and farmed salmonids and can cause considerable damage to infected fish. We have examined the effect of the organophosphate trichlorphon, which was one of the early treatments for sea lice as Neguvon^® on L. salmonis. Suppression subtractive hybridisation was used to prepare a cDNA library enriched for cDNAs expressed in response to the organophosphate trichlorophon and using this technique a total of 33 cDNAs were found to be differentially regulated in response to organophosphate exposure. Sequence analysis of the cDNAs revealed that many were involved in cellular stress responses and or neurotoxicity. The expression of two of these cDNAs was confirmed to be up-regulated in response to trichlorophon.