| Description |
Aquatic environments are filled with viruses that affect the health of these crucial ecosystems. However, little is known about these viruses and their methods of transmission. Tetrahymena, a model eukaryotic ciliate found in freshwater environments, seem to hold a clue to viral transmission because of their generous consumption of viral particles. Tetrahymena are additionally consumed themselves, suggesting they may be a key contributor to virus movement-a ciliate viral vehicle. We are interested in Aquareoviruses, a genus of double stranded RNA viruses that infect fish, crustaceans, and mollusks. Previous research shows that the Aquareovirus Chum Salmon Reovirus (CSV) becomes more infectious when incubated with Tetrahymena. Our question expands on this study by asking if the finding with CSV applies to all Aquareoviruses and what the mechanism is that Tetrahymena use to alter these viruses. We found that another Aquareovirus, Eel Lake Virus, has a similar increase in infectivity when exposed to Tetrahymena while two others in the same genus, 13p2 and Green River Virus, do not have the same increase. We hypothesize that Tetrahymena proteases digest the outer capsid of these viruses, exposing more infectious proteins. In using a mutant of Tetrahymena thermophila, ΔVPS8A, that has a deficient phagocytosis pathway, we found surprisingly that these mutant Tetrahymena yielded an even higher CSV viral titer. Additionally, the ΔVPS8A mutants were shown to retain ink in their vacuoles at a higher density than the wildtype Tetrahymena. Our future directions include using a protease inhibitor to see if digestion by proteases within the ciliate is causing this higher infectivity in CSV. These experiments will develop a model to understand Tetrahymena as a vector for aquatic viral transmission. |
