Everything You Always Wanted to Know about the Kissing Bug, But Were Afraid to Ask
The lecture hall in the Instructional Centre at U of T Mississauga was near capacity for the inaugural Research Excellence Award Lecture that was held Thursday, December 5
Professor Ian Orchard from U of T Mississauga’s Department of Biology held a captive audience Thursday evening with a talk that covered lots of ground including his extensive insect research, the history and effects of Chagas’ disease, how his work relates to neural communication and the Rhodnius-Genome project with which his lab is involved.
As a recipient of the 2013 Research Excellence Award, Orchard delivered the talk, “The Kiss of Death: Rhodnius prolixus, Chagas’ disease and what has this to do with neuroscience?” It was an engaging discussion for those in attendance to learn some of the details of Orchard’s lifework, and the audience was an extensive assemblage of staff, students and faculty members from various departments across UTM.
In his introduction to the lecture, Vice-Principal Bryan Stewart mentioned that Orchard is a “world-renowned insect neurophysiologist,” and has worked on insect neural systems and neuroendocrinology with a variety of specimens, such as locusts, leeches, lobsters and mollusks, over the years.
Stewart also divulged that he was a graduate student hired on as a Teaching Assistant in Harold Atwood and Orchard’s course nearly thirty years ago, soon after Orchard came to U of T in 1982.
“I, personally, am fascinated by the shapes of neurons, and I could look at them all day. I think they are a thing of beauty,” Orchard said early on in the seminar. “While you stare at them you can also question how they are working. The advantage of neuroscience and neurophysiology is that you can actually intercept the electrical signals in real time, and so therefore see what they are doing.”
Orchard went on to describe the ways in which the neurons transmit information to other cells and how the G protein-coupled receptors (GPCRs) factor into the process.
Audience members were also treated to short animations of the feeding frenzy of the “kissing bug” Rhodnius prolixus, which can go a year without eating, but when it feasts it can consume ten times its body weight in approximately 20 minutes, the only animal with this ability, before it urinates on its victim. This blood-feeding insect is mainly found in Central and South America, and harbors the parasite responsible for Chagas’ disease in humans, the most common cause of heart failure and for which there is no cure.
What Orchard’s lab is mainly concerned with is studying Rhodnius’s changed state after they feed when the insects become immobile, and Orchard and his colleagues focus in on the processes that controls diuresis and antidiuresis, the mechanisms that stimulate and control the production of urine.
They have discovered ultimately the first neurohormone (serotonin) and its receptor, and also neuropeptides that control diuresis. These neurons also then control the transmission of Chagas’ disease, which is only spread because the bug urinates on its victim thereby passing along the parasite.
There is a great interest and proven justification for sequencing the Rhodnius genome, and after receiving significant funding from the National Institutes of Health (NIH), who recognizes the value in the work being done by Canadian researchers as well as their international collaborators and counterparts, the work on this particular insect continues.
“It has revolutionized the work we particularly do, as well as the work of others in this area,” says Orchard. “The power of the genome is that it gives us the tools for identifying the genes, these neurohormones and their GPCRs, allowing us to disrupt the signaling and investigate the involvement of the chemicals in physiology, and see exactly what those hormones are doing.”
The Research Excellence Award was established to recognize the exceptional research at U of T Mississauga and is awarded to an individual who has had impact through their contributions to their respective fields and with their connections to the students, post-docs and the community. The Research Excellence Award Lectureship will annually feature the award recipient.
- By Carla DeMarco