Cholinesterase characterization in Corbicula fluminea and effects of relevant environmental contaminants: A pesticide (chlorfenvinphos) and a detergent (SDS)

Abstract

This study characterizes the cholinesterasic forms present in the bivalve Corbicula fluminea, through the analysis of differential affinity towards various substrates and inhibitors. This approach also permitted the validation of cholinesterase inhibition in the mentioned species for monitoring purposes by evaluating the inhibitory activity of a detergent (SDS) and a pesticide (chlorfenvinphos), both in vitro and in vivo. The cholinesterasic form present in the tissues of C. fluminea showed intermediate properties in terms of its relation with substrates and inhibitors. Furthermore, it was not inhibited by the detergent SDS under any of the test conditions, but was clearly inhibited by the selected organophosphate. The data show clearly that the main cholinesterasic form in C. fluminea is responsive to the organophosphate chlorfenvinphos, thus supporting the use of this biomarker for the environmental monitoring of specific contaminants such as anticholinesterasic pesticides. Despite not being commonly attained in the wild, the levels of chlorfenvinphos required to elicit a significant ChE inhibition were only one order of magnitude above actual values of aquatic contamination by this pesticide.

Keywords:

• Cholinesterases (ChEs)
• anti-cholinesterasic compounds
• biomarker
• Corbicula fluminea
• environmental monitoring
• Chlorfenvinphos
• SDS

Acknowledgments

The present work was partially funded by Fundação para a Ciência e a Tecnologia: project “BiOtoMetal” (PTDC/AMB/70431/2006) and project “CONTROLCLAM” (PTDC/AAC-AMB/113515/2009). Sara Antunes was the recipient of a post-doctoral fellowship (SFRH/BPD/40052/2007). Ana Ramos was recipient of a FCT scholarship (BII/CESAM/46539/2009).