ARS | Publication request: Complexity of acetylcholinesterases in biting flies and ticks

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 31, 2012
Publication Date: N/A

Technical Abstract: Acetylcholinesterase (AChE) inhibitors function as pesticides for invertebrates, vertebrate nerve agents, and medicine to reduce cognitive effects of Alzheimer’s disease. Organophosphate (OP) pesticides have been widely used to control biting flies and ticks, however, OP-resistance has compromised control efficacy, often by production of OP-insensitive AChEs. Complimentary DNA (cDNA) sequences encoding AChEs have been obtained for horn flies, stable flies, sand flies and cattle ticks. These cDNA sequences enable searches for mutations, expression and biochemical characterization of recombinant AChEs, gene silencing for functional genomics, and in vitro screening of novel inhibitors. Such studies have identified novel inhibitors with potential application for sand fly control. Multiple AChE genes are expressed in ticks and some other invertebrates. Copy number amplification and expression of multiple alleles in the central nervous system for several of the tick AChE genes may reduce fitness cost associated with OP-resistance. AChE hydrolyzes the neurotransmitter, acetylcholine, and may play additional roles in physiology and development. AChE expression in tick saliva and other non-neural tissues suggests involvement in manipulation of host responses to promote successful blood feeding and reproduction. The remarkable complexity of AChE and its key role in neural transmission present significant difficulties for studies of non-canonical functions of AChE in vertebrates. Comparison of invertebrate AChEs with vertebrates may provide AChE model systems with separation of structure and function resulting in reduced complexity of interactions and advantages for experimentation in whole organisms implausible for vertebrate systems. A systems biology approach using invertebrate models may therefore provide opportunities for elucidation of non-classical AChE functions potentially conserved with vertebrate systems. USDA is an equal opportunity provider and employer