2010/731 Discovery and manipulation of Neoparamoeba perurans aquaporins as a means to treat Amoebic Gill Disease (AGD)

By Mathew Cook, Ewan Campbell and Andrea Yool

Amoebic gill disease (AGD) is the number one health concern related to the production of Atlantic Salmon in Tasmania, accounting for approximately 10% of production costs. Despite much research effort, freshwater bathing still remains the only effective treatment option. This is however both difficult and expensive and not viable in the long term especially if leases are to be established further off shore. Currently, selective breeding is an attractive option for the mitigation of AGD, but is a long term strategy and is unlikely to be 100% effective. Therefore there is a need to explore other opportunities that may provide relief to AGD, particularly in the short to medium term.

Aquaporins (AQPs) are thought to be a group of ancient proteins that are highly conserved throughout all branches of life. They are essential membrane channels for the movement of water and small solutes such as glycerol and urea, and are found in bacteria, protozoa, plants and animals. There is a need to correctly identify the N. perurans AQPs at the molecular level, to undertake preliminary studies to show that they can be blocked without affecting Atlantic Salmon AQPs, and to show that block of the parasite AQPs results in inhibition or death of N. perurans. Central to this work is a need to develop low cost, rapid and reliable assays of salmon gill cell – Neoparamoeba interactions. This project aimed to address this need.

Despite numerous attempts and different strategies researchers were unable to identify and clone AQP genes from the causative agent of AGD, Neoparamoeba perurans. However, they were able to develop protocols for the establishment of short term cultures of Atlantic Salmon gill cells. This is the first step toward the development of a rapid in-vitro assay system for studying the interactions between N. perurans and Atlantic Salmon gill cells.