Authors

Discussion

The Pseudophyllidian cestode Schistocephalus solidus has been observed manipulating the behaviour of their secondary intermediate hosts, the three-spined stickleback (Gasterosteus aculeatus) to promote parasite transmission. Recent research has demonstrated that some level of manipulation occurs at the molecular level, moving away from solely the physical presence of the parasite within the body cavity of the host. The excretory secretory proteins (ESP) produced by the plerocercoid stage has been examined in relative depth and has yielded novel putative host manipulating proteins.  A crucial part of the secretome, so far neglected in S. solidus, is the presence, or indeed absence, of extracellular vesicles (EVs).  EVs have been widely demonstrated to be secreted from a number of helminths including both trematodes and cestodes.  Therefore, given that the molecular mechanism of how S. solidus manipulates its host is unknown, there exists the potential that S. solidus derived EVs may act as a crucial host manipulator.  Therefore, this project is expanding the known secretome of S. solidus through the investigation of both the free secreted proteins and EVs released from S. solidus into the host itself using a GeLC proteomic approach. S. solidus parasites were collected from natural infections and maintained in vitro.  ESPs and EVs were purified using size exclusion chromatography and subjected to 1D SDS PAGE analysis followed by mass spectrometry.  Preliminary evidence suggests the presence, albeit low, of EVs within the S. solidus secretome providing the most complete S. solidus secretome to date.  Exploring the impact of S. solidus derived EVs will further complement our understanding of putative host manipulation molecules.