Abstract
BackgroundThe salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod which feeds on the mucus, skin and blood of salmonid fish species. The parasite can persist on the surface of the fish without any effective control being exerted by the host immune system. Other ectoparasitic invertebrates produce compounds in their saliva, excretions and/or secretions which modulate the host immune responses allowing them to remain on or in the host during development. Similarly, compounds are produced in secretions of L. salmonis which are thought to be responsible for immunomodulation of the host responses as well as other aspects of crucial host-parasite interactions.MethodsIn this study we have identified and characterised the proteins in the excretory/secretory (E/S) products of L. salmonis using LC-ESI-MS/MS.ResultsIn total 187 individual proteins were identified in the E/S collected from adult lice and pre-adult sea lice. Fifty-three proteins, including 13 serine-type endopeptidases, 1 peroxidase and 5 vitellogenin-like proteins were common to both adult and pre-adult E/S products. One hundred and seven proteins were identified in the adult E/S but not in the pre-adult E/S and these included serine and cysteine-type endopeptidases, vitellogenins, sphingomyelinase and calreticulin. A total of 27 proteins were identified in pre-adult E/S products but not in adult E/S.ConclusionsThe assigned functions of these E/S products and the potential roles they play in host-parasite interaction is discussed.
Highlights
The salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod which feeds on the mucus, skin and blood of salmonid fish species
Protein profiles in E/S products In total, 187 individual proteins were identified from E/S collected from adult and pre-adult sea lice
Adult E/S products displayed a wide spectrum of molecular weights with multiple discrete bands present between 24–220 kDa (Fig. 1a)
Summary
The salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod which feeds on the mucus, skin and blood of salmonid fish species. Proteases are secreted by L. salmonis [12,13,14] as well as other parasitic copepod species [15] and are thought to be important for feeding and immune evasion. Serine proteases such as trypsins, thought to be of L. salmonis origin, have been reported in salmon mucus [12] and in L. salmonis excretory/secretory (E/S) products [11]. Several of these trypsin-like serine proteases have been characterised and have increased mRNA transcript levels in the parasite midgut through all life stages as well as a suggested role in protein digestion [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
