Inhibitory effects of four neonicotinoid active ingredients on acetylcholine esterase activity

János Győri, A. Farkas, Oksana Stolyar, A. Székács, Mária Mörtl, A. Vehovszky

Research output: Contribution to journalArticle

Abstract

There is a great concern about the decline of pollinators, and neonicotinoids emerging bee disorders are assumed to play a significant role. Since changes in learning ability has been observed in honey bees exposed to some acetylcholine esterase (AChE) inhibitors, we therefore, tested in vitro the effect of four neonicotinoids on purified eel AChE. AChE activity was inhibited in a concentration-dependent manner, and calculated IC50 values for thiamethoxam (IC50 = 414 μM) and clothianidin (IC50 = 160 μM) were found to be much higher compared to acetamiprid (IC50 = 75.2 μM) and thiacloprid (IC50 = 87.8 μM). The Lineweaver-Burk reciprocal plots for acetamiprid shows unchanged Vmax and increased Km values with inhibitor concentrations, while analysis of Michaelis-Menten plots shows predominantly competitive mechanism. The inhibition constant value (Ki = 24.3 μM) indicates strong binding of the acetamiprid complex to AChE. Finally, the four tested neonicotinoids are not a uniform group regarding their blocking ability. Our results suggest a previously not established, direct AChE blocking mechanism of neonicotinoids tested, thus the neuronal AChE enzyme is likely among the direct targets of the neonicotinoid insecticides. We conclude, that these AChE inhibitory effects may also contribute to toxic effects on the whole exposed animal.

Original languageEnglish
Pages (from-to)345-357
Number of pages13
JournalActa Biologica Hungarica
Volume68
Issue number4
DOIs
Publication statusPublished - Dec 1 2017

Fingerprint

Esterases
Acetylcholine
Inhibitory Concentration 50
bee
Aptitude
inhibitor
Bees
thiamethoxam
honey
eel
pollinator
Eels
insecticide
Honey
Poisons
learning
Insecticides
neonicotinoid pesticide
effect
enzyme

Keywords

  • acetamiprid
  • clothianidin
  • in vitro acetylcholinesterase assay
  • Neonicotinoids
  • thiamethoxam

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Environmental Science(all)
  • Neurology

Cite this

Inhibitory effects of four neonicotinoid active ingredients on acetylcholine esterase activity. / Győri, János; Farkas, A.; Stolyar, Oksana; Székács, A.; Mörtl, Mária; Vehovszky, A.

In: Acta Biologica Hungarica, Vol. 68, No. 4, 01.12.2017, p. 345-357.

Research output: Contribution to journalArticle

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