Comparative analysis of neonicotinoid binding to insect membranes: II. An unusual high affinity site for [3H]thiamethoxam in Myzus persicae and Aphis craccivora
- 16 June 2004
- journal article
- research article
- Published by Wiley in Pest Management Science
- Vol. 60 (10), 959-970
- https://doi.org/10.1002/ps.920
Abstract
Neonicotinoids represent a class of insect‐selective ligands of nicotinic acetylcholine receptors. Imidacloprid, the first commercially used neonicotinoid insecticide, has been studied on neuronal preparations from many insects to date. Here we report first intrinsic binding data of thiamethoxam, using membranes from Myzus persicae Sulzer and Aphis craccivora Koch. In both aphids, specific binding of [3H]thiamethoxam was sensitive to temperature, while the absolute level of non‐specific binding was not affected. In M persicae, binding capacity (Bmax) for [3H]thiamethoxam was ca 450 fmol mg−1 of protein at 22 °C and ca 700 fmol mg−1 of protein at 2 °C. The negative effect of increased temperature was reversible and hence not due to some destructive process. The affinity for [3H]thiamethoxam was less affected by temperature: Kd was ca 11 nM at 2 °C and ca 15 nM at 22 °C. The membranes also lost binding sites for [3H]thiamethoxam during prolonged storage at room temperature, and upon freezing and thawing. In A craccivora, [3H]thiamethoxam was bound with a capacity of ca 1000 fmol mg−1 protein and an affinity of ca 90 nM, as measured at 2 °C. Overall, the in vitro temperature sensitivity of [3H]thiamethoxam binding was in obvious contrast to the behaviour of [3H]imidacloprid studied in parallel. Moreover, the binding of [3H]thiamethoxam was inhibited by imidacloprid in a non‐competitive mode, as shown with M persicae. In our view, these differences demonstrate that thiamethoxam and imidacloprid, which represent different structural sub‐classes of neonicotinoids, do not share the same binding site or mode. This holds also for other neonicotinoids, as we report in a companion article. Copyright © 2004 Society of Chemical IndustryKeywords
This publication has 18 references indexed in Scilit:
- Comparative analysis of neonicotinoid binding to insect membranes: I. A structure–activity study of the mode of [3H]imidacloprid displacement in Myzus persicae and Aphis craccivoraPest Management Science, 2004
- Thiamethoxam is a neonicotinoid precursor converted to clothianidin in insects and plantsPesticide Biochemistry and Physiology, 2003
- SELECTIVE TOXICITY OF NEONICOTINOIDS ATTRIBUTABLE TO SPECIFICITY OF INSECT AND MAMMALIAN NICOTINIC RECEPTORSAnnual Review of Entomology, 2003
- Chemistry and biology of thiamethoxam: a second generation neonicotinoidPest Management Science, 2001
- Structure and diversity of insect nicotinic acetylcholine receptorsPest Management Science, 2001
- Insect Nicotinic Acetylcholine Receptor: Conserved Neonicotinoid Specificity of [3H]Imidacloprid Binding SiteJournal of Neurochemistry, 2000
- Characterisation of multiple α-bungarotoxin binding sites in the aphid Myzus persicae (Hemiptera: Aphididae)Insect Biochemistry and Molecular Biology, 1999
- CGA 293’343: A Novel, Broad-Spectrum Neonicotinoid InsecticidePublished by Springer Science and Business Media LLC ,1999
- [3H]Imidacloprid Labels High- and Low-Affinity Nicotinic Acetylcholine Receptor-like Binding Sites in the AphidMyzus persicae(Hemiptera: Aphididae)Pesticide Biochemistry and Physiology, 1998
- High Affinity Binding of [3H]Imidacloprid in the Insect Acetylcholine ReceptorPesticide Biochemistry and Physiology, 1993