title: Melanogenesis in visceral tissues of Salmo salar. A link between immunity and pigment production?
abstract: Melanogenesis is mostly studied in melanocytes and melanoma cells, but much less is known about other pigment cell systems. Liver, spleen, kidney, and other organs of lower vertebrates harbour a visceral pigment cell system with an embryonic origin that differs from that of melanocytes. In teleosts, melanin-containing cells occur in the reticulo-endothelial system and are mainly in the kidney and spleen. The Atlantic salmon (Salmo salar L.) is an ichthyic breeding species of considerable economic importance. The accumulation of pigments in salmon visceral organs and musculature adversely affects the quality of fish products and is a problem for the aquaculture industry. With the aim to reveal novel functions and behaviour of the salmonid extracutaneous pigment system, we investigated aspects of the melanogenic systems in the tissues of Atlantic salmon, as well as in SHK-1 cells, which is a long-term cell line derived from macrophages of the Atlantic salmon head-kidney. We demonstrate that a melanogenic system is present in SHK-1 cells, head-kidney, and spleen tissues. As teleosts lack lymph nodes and Peyer's patches, the head-kidney and spleen are regarded as the most important secondary lymphoid organs. The detection of tyrosinase activity in lymphoid organs indicates that a link exists between the extracutaneous pigmentary system and the immune system in salmon.
authors.affiliation: Sezione di Biologia Medica, Dipartimento di Scienze Mediche di Base, Neuroscienze ed Organi di Senso, Università degli Studi di Bari, Policlinico-Piazza Giulio Cesare, 70124 Bari, Italy.
authors.forename: Marcella
authors.initials: M
authors.lastname: Arciuli
authors.forename: Daniela
authors.initials: D
authors.lastname: Fiocco
authors.forename: Rosina
authors.initials: R
authors.lastname: Cicero
authors.forename: Immacolata
authors.initials: I
authors.lastname: Maida
authors.forename: Paola T
authors.initials: PT
authors.lastname: Zanna
authors.forename: Gabriella
authors.initials: G
authors.lastname: Guida
authors.forename: Tor E
authors.initials: TE
authors.lastname: Horsberg
authors.forename: Erling O
authors.initials: EO
authors.lastname: Koppang
authors.forename: Anna
authors.initials: A
authors.lastname: Gallone
mesh_terms: D000818:Animals; D002460:Cell Line; D060226:Head Kidney / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008543:Melanins / Q000378:metabolism*; D008544:Melanocytes / Q000378:metabolism*; D009928:Organ Specificity; D020317:Salmo salar / Q000276:immunology* / Q000378:metabolism*; D013154:Spleen / Q000378:metabolism
chemical_list: D008543:Melanins