My research involves biochemical analysis of venom from a fascinating parasitoid jewel wasp Ampulex compressa. Most parasitoid wasps envenomate the host by stinging into the body cavity to cause paralysis and developmental arrest, prior to deposition of eggs externally or within the body cavity. A. compressa instead uses a different subjugation strategy by injecting venom directly into the central nervous system, eliciting a behavioral sequence culminating in hypokinesia, a 7–10 day lethargy advantageous to wasp reproduction. Hypokinesia is a specific, venom-induced behavioral state characterized by suppression of the escape response and reduced spontaneous walking, leaving other motor functions unaffected. This specificity of action is particularly unique among venoms and interestingly, effects of the venom on the escape response are reversible as the cockroach may recover after 7–10 days if not consumed by the wasp larvae. Venom-induced hypokinesia raises an interesting biological question: How can such a potent biochemical cocktail cause such long-lasting, specific, yet reversible effects on behavior? I approached this question in two ways: objective one—bioinformatic analysis of the venom and venom gland tissue to determine what the venom is made of, and objective two—functional analysis of key venom components to determine how the venom works. To address objective 1, I used advanced bioinformatics techniques to generate transcriptomes of the venom tissue and proteomes of the venom and venom tissue. Next generation sequencing of venom gland RNA has yielded full-length coding sequences and quantification of venom transcript levels, while mass spectroscopy based protein analysis has validated the presence of venom proteins. These analyses will allow construction of a comprehensive A. compressa “venome” that will help inform functional analyses of the venom and its role in hypokinesia induction. For objective two, I focused on the characterization of the most abundant peptide in the venom, tentatively named Ampulexin 1, and pharmacological analysis of an interesting venom peptide neurotransmitter, called tachykinin. Analysis of venom tachykinin action on cockroach brain receptors may reveal an interesting case of the evolution of a neurotransmitter from one animal to target the nervous system of another.
|Advisor:||Adams, Michael E.|
|Commitee:||Ray, Anandasankar, Stajich, Jason E.|
|School:||University of California, Riverside|
|Department:||Biochemistry and Molecular Biology|
|School Location:||United States -- California|
|Source:||DAI-B 78/01(E), Dissertation Abstracts International|
|Subjects:||Biochemistry, Bioinformatics, Parasitology|
|Keywords:||Ampulex compressa, Proteomics, Tachykinin, Transcriptomics, Venom, Venome|
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