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Stopping disease spread
Even before coming to Purdue, Hogenkamp recognized the need to find innovative ways to stop disease-spreading insects in their tracks. In his doctoral research at Kansas State, he used molecular biology to investigate insect development and chitin, a polymer that strengthens and supports insects’ external skeleton and other structures. Understanding chitin might reveal new methods to destroy bugs.
The job in Hill’s lab would give him the opportunity to follow additional novel research paths to prevent bugs from victimizing people. In June 2006, Hogenkamp moved to West Lafayette with his wife Theresa and their two young sons, Jacob and Tyler, to begin a job as senior laboratory researcher for Purdue’s part in the mosquito project.
Theresa says the former Army infantryman and Upward Bound teacher worked his way through college and grad school for his goal to be a professor and a researcher. “He was always reading and was a really good teacher,” Theresa says. “He loved to figure things out and then show other people how to do it.”
The task for Hogenkamp and the rest of Hill’s team was to search the Aedes genome for a family of proteins that controls some mosquito behaviors. G protein-coupled receptors, GPCRs for short, are proteins that sit on the surface of cells to transport signals from outside a cell into the cell, then transform the messages to internal signals that cause biochemical changes. These receptors are found in all animals, including mosquitoes and mammals.
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| The Aedes aegypti mosquito |
GPCRs’ signaling function affects smell, taste, sight, cell development and the nervous system. GPCRs involved in detecting smells—olfactory receptors—are especially interesting since mosquitoes use odors to locate an arm or a leg or other body part for their next meal and to find a site to lay eggs.
“If we can better understand the molecular basis of sensory behaviors in mosquitoes, then that can translate into designing better repellants, attractants and insecticides,” Hill says.
Finding something new
GPCRs had been catalogued in the mosquito Anopheles gambiae, a carrier of malaria, which causes more death worldwide than any other illness. Hogenkamp discovered 130 GPCRs in Aedes, many of which never had been described in any other organism, while some were duplicated in Anopheles.
With further study of mosquito GPCRs and genomes, researchers will be able to tell why Aedes is so different from Anopheles. They already know that Aedes has a much larger and more complicated genome than the malaria-carrying species and that the two insects followed different evolutionary paths about 180 million years ago.
Uncovering further differences and similarities among Aedes, Anopheles and the West Nile virus-transporting Culex pipiens GPCRs may answer “the million-dollar question,” Hill says. “Why does one mosquito species carry one type of disease but not another?
“Having the genome and the GPCRs could tell us why Aedes can transmit yellow fever and dengue fever, but not malaria,” she says. “By understanding that theory, we could try to develop ways to prevent transmission of those diseases.”
Hogenkamp’s legacy, built in just a few years, is huge in the world of science.
“Dave’s GPCR work will lead to an improved understanding of mosquito sensory behavior and the mosquito genome,” Hill says. “Dave has opened up a whole new field of research that has created opportunities for other scientists to do investigations for years to come.”
Contact Susan A. Steeves at ssteeves@purdue.edu
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