Airway immunity in the Madagascar hissing cockroach (Gromphadorhina portentosa)
North Dakota State University Biological Sciences
Austin A Espe, Nathan A Fisher, Kendra J Greenlee
Respiratory systems have evolved to maximize oxygen delivery and also serve to protect the host from invading pathogens. The immunopathology of the respiratory system is not well understood in insects. Previous studies found the presence of antimicrobial peptides in insect tracheae. However, many of these studies were conducted in Drosophila melanogaster, which have small tracheae. To better understand how insect respiratory systems protect against pathogens we used an insect with large tracheae, the Madagascar hissing cockroach (Gromphadorhina portentosa). To investigate airway immunity in G. portentosa, we will inoculate the thoracic tracheae with Escherichia coli, assess cockroach survival, and measure bacterial load of inoculated tracheae. To determine if the infection spreads from the tracheae, hemolymph will be tested for the presence of bacteria. Future work will identify the mechanism of host protection by assessing antimicrobial peptide activity and hemocyte responses. We predict that antimicrobial immune responses in the airways of G. portentosa will be similar to those found in D. melanogaster. Determining the airway immune responses to E. coli in G. portentosa will improve our understanding of how airway immunity has evolved.
