Dose-response to metaldehyde and cytochrome P450 levels in Bradybaena similaris populations which have and have not had previous pesticide exposure
S. Salmijah, P.L. Chan, K.K. Wong, A. Maimon and B.S. Ismail, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia.
This study was designed to investigate the dose response of Bradybaena similaris to metaldehyde in populations which have had previous multiple exposure to the chemical at Cameron Highlands, Pahang and populations that never had exposure to any type of pesticides at Pos Piah, Perak. The base levels of cytochrome P450 (CYP) activities in the two populations were also investigated. The results showed that the 24 hour dose response profile of metaldehyde on B. similaris samples from Cameron Highlands differed from that observed on the B. similaris samples from Pos Piah. The snails from Cameron Highlands displayed the highest mortality of 85% at 4% metaldehyde and decreased thereafter. In contrast, the mortality rate of snails from Pos Piah was found to increase proportionally to 71.7% at the highest metaldehyde dose tested (7.0%). There was no significant difference (P >0.05) in the total cytochrome P450 hemoprotein measured from both the whole tissues and the hepatopancreas for the two populations. However, the CYP2B activity was significantly higher (P <0.05) in snails which have had unremitting exposure to metaldehyde, suggesting that CYP2B is selectively induced in these animals by metaldehyde.
Keywords: Bradybaena similaris, cytochrome P450, metaldehyde, pesticide.
Plant Protection Quarterly (2006) 21 (4) 163-165.