Characterisation of proteins in excretory/secretory products collected from salmon lice, Lepeophtheirus salmonis

Background  The 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.  Methods  In this study we have identified and characterised the proteins in the excretory/secretory (E/S) products of L. salmonis using LC-ESI-MS/MS.  Results  In 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.  Conclusions  The assigned functions of these E/S products and the potential roles they play in host-parasite interaction is discussed

Improving dopant incorporation during femtosecond-laser doping of Si with a Se thin-film dopant precursor

We study the dopant incorporation processes during thin-film fs-laser doping of Si and tailor the dopant distribution through optimization of the fs-laser irradiation conditions. Scanning electron microscopy, transmission electron microscopy, and profilometry are used to study the interrelated dopant incorporation and surface texturing mechanisms during fs-laser irradiation of Si coated with a Se thin-film dopant precursor. We show that the crystallization of Se-doped Si and micrometer-scale surface texturing are closely coupled and produce a doped surface that is not conducive to device fabrication. Next, we use this understanding of the dopant incorporation process to decouple dopant crystallization from surface texturing by tailoring the irradiation conditions. A low-fluence regime is identified in which a continuous surface layer of doped crystalline material forms in parallel with laser-induced periodic surface structures over many laser pulses. This investigation demonstrates the ability to tailor the dopant distribution through a systematic investigation of the relationship between fs-laser irradiation conditions, microstructure, and dopant distribution