, 2010). Salmon lice affect host physiology, suppress host

immune responses and are suspected as vectors for other pathogens ( Nowak et al., 2010, Nylund et al., 2010, Nylund et al., 1994 and Jakob et al., 2011). Because of the adverse effects on the hosts and indicated negative effects salmon louse have on some wild populations, it has been identified this website as one of the major challenges to salmonid aquaculture. If not kept under control, it represents a potentially severe burden for farmed and unfarmed salmonids ( Costello, 2006). Control has hitherto relied on a limited number of chemotherapeutants, but environmental concerns and reports of resistance have spurred broad research on

the salmon louse including studies of their molecular biology ( Carmichael et al., 2013, Dalvin et al., 2011, Eichner et al., 2008, Fallang et al., 2005, Fallang selleck inhibitor et al., 2004, Kvamme et al., 2004 and Treasurer et al., 2000). The available salmon louse genome assemblies (sealouse.imr.no and www.ncbi.nlm.nih.gov/genbank) are important resources when embarking on studies of uncharacterized salmon louse genes. However, additional information about spatiotemporal expression patterns are of dire importance when evaluating predicted gene functions. Therefore, we have characterized the spatial expression pattern of 11,100 genes using a 44 K oligomicroarray. In the present study, five different types of tissue were sampled from adult salmon lice (Fig. 1). The ovaries and testes aminophylline are paired organs positioned on each side of the coalesced eyes just below the cuticula and are easily identified. In female lice, the ovaries have a continuous production of oocytes that are transported via the oviduct to the genital segment where egg maturation takes place. In males, testes produce spermatozytes that are deposited on the females by transfer of spermatophores. Digestion of the blood, slime and skin cells from the salmonid host takes place in the

gut. The gut is an elongated organ that stretches from the mouth found in the anterior part on the underside of the animal to the rectum in the very end of the abdominal segment. The gut content is repeatedly homogenized by muscular mixing and the gut appears to be undifferentiated (Kvamme et al., 2004 and Nylund et al., 1992). There is no hepatopancreas associated with the gut as found among many other crustacean taxa. The subcuticular tissue is a tissue type found throughout the louse just below the cuticula. In adult females, this tissue type is characterized by high expression of vitellogenins and a yolk associated protein (Dalvin et al., 2011 and Dalvin et al., 2009). In the present paper we have additionally dissected out a sample defined as frontal tissue.