April 11, 2023
Shelley Adamo to present Biochemistry and Molecular Biophysics Seminar on April 12
Submitted by Biochemistry and Molecular Biophysics
Shelley Adamo, professor of psychology and neuroscience at Dalhousie University, will be the featured speaker for this week’s Biochemistry and Molecular Biophysics Seminar. Adamo will present "Cost and Benefits of Immunophysiological Responses in the Caterpillar" at 4 p.m. Wednesday, April 12, in 120 Ackert Hall.
Presentation abstract: Defense against life-threatening challenges, such as pathogens, activates an organismwide response. The organization of this network allows the immune system to borrow additional resources as needed. However, this flexibility comes at a price. It results in physiological trade-offs with other functions and the need for chemical signals to organize the re-allocation of resources. For example, skeletal muscle is a specialized tissue that provides the motor for movement, but it also participates in the immune response. We show that during this multitasking, there is a physiological trade-off in the caterpillar Manduca sexta resulting in a reduction in the amount of glycogen in muscle.
During an immune challenge, the force of the defensive strike, an important anti-predator behavior in M. sexta, was also reduced. Caterpillars were also less able to defend themselves against the wasp Cotesia congregata, suggesting that the effect on muscle is biologically significant. We suggest that increased mortality from predation is a non-immunological cost of infection in M. sexta.
Adamo's study also suggests that one reason non-immunological costs of infection exist is because of the participation of diverse organs, such as muscle, in immunity. In a second example, the parasitic wasp Cotesia congregata exploits the chemical signaling system between the immune system and nervous system to manipulate its host's behavior. The wasp lays her eggs inside the caterpillar. During wasp larval development, the caterpillar's behavior is normal. But after the wasps scrape their way through the host's body wall to the outside, the caterpillar’s behavior shows a dramatic change. It loses all self-motivated behaviors such as feeding and locomotion. The host becomes a bodyguard of the cocoons as they mature into adult wasps. The wasps use a variety of methods to manipulate host behavior, including a domesticated virus to introduce novel genes into the brain of their host. The wasps use these methods to hyperactivate immune-neural signaling, resulting in augmented sickness behaviors, such as malaise and illness-induced anorexia.