Acetylcholinesterase (AChE) is a target enzyme of organophosphate (OP) and carbamate (CB) insecticides. Point mutation in AChE is one of the major mechanisms of OP and CB resistance. Recently, we investigated soluble AChEs abundantly expressed in the non-neuronal tissues of the honey bee Apis mellifera and fruit fly Drosophila melanogaster. Pre-incubation of OP and CB insecticides with honey bee soluble AChE showed a significant reduction in the inhibition of catalytic AChE activity. In the fruit fly, expression of soluble AChE was induced by insecticide exposure, and the wild-type fly expressing both soluble and membrane-anchored AChEs was more tolerant to insecticide than the transgenic fly expressing only membrane-anchored AChE. These findings suggested that soluble form of AChE is possibly involved in chemical defense against xenobiotics, including insecticides.

Acetylcholinesterase (AChE) is an enzyme for hydrolyzing neurotransmitter acetylcholine. Soluble form of AChE is generated via alternative splicing and functions as a bioscavenger in Dropsophila melanogaster. In this study, effects of ethanol and acetic acid on the soluble AChE expression were investigated. Treatment of ethanol and acetic acid results in over-expression of soluble AChE in the abdomen in a dose-dependent manner. However, no apparent change in AChE expression was observed in the head. Our finding suggests that the soluble AChE is involved in chemical defense against high concentration of ethanol, which is a common by-product from fermented food，and acetic acid, the main metabolite of ethanol. Thus, high level of ethanol and acetic acid resistance in D. melanogaster appears to be evolved via the induction mechanism of soluble AChE expression.

Acetylcholinesterase (AChE) is a hydrolase that hydrolyzes the neurotransmitter acetylcholine. Soluble form of AChE is generated via alternative splicing and functions as a bioscavenger in Dropsophila melanogaster. In this study, effects of acetic acid on the soluble AChE expression were investigated. Treatment of acetic acid resulted in over-expression of soluble AChE in the abdomen in a dose-dependent manner. The soluble AChE was determined to be expressed in the fat body. However, no apparent change in AChE expression was observed in the head. Our finding suggests that the soluble AChE is involved in chemical defense against high concentration of acetic acid, which is a common by-product in fermenting foods. The high level of acetic acid resistance in D. melanogaster, thus, appears to have been evolved via the induction mechanism of soluble AChE expression.