title: Photoprotection in sequestered plastids of sea slugs and respective algal sources.
abstract: Some sea slugs are capable of retaining functional sequestered chloroplasts (kleptoplasts) for variable periods of time. The mechanisms supporting the maintenance of these organelles in animal hosts are still largely unknown. Non-photochemical quenching (NPQ) and the occurrence of a xanthophyll cycle were investigated in the sea slugs Elysia viridis and E. chlorotica using chlorophyll fluorescence measurements and pigment analysis. The photoprotective capacity of kleptoplasts was compared to that observed in their respective algal source, Codium tomentosum and Vaucheria litorea. A functional xanthophyll cycle and a rapidly reversible NPQ component were found in V. litorea and E. chlorotica but not in C. tomentosum and E. viridis. To our knowledge, this is the first report of the absence of a functional xanthophyll cycle in a green macroalgae. The absence of a functional xanthophyll cycle in C. tomentosum could contribute to the premature loss of photosynthetic activity and relatively short-term retention of kleptoplasts in E. viridis. On the contrary, E. chlorotica displays one of the longest functional examples of kleptoplasty known so far. We speculate that different efficiencies of photoprotection and repair mechanisms of algal food sources play a role in the longevity of photosynthetic activity in kleptoplasts retained by sea slugs.
authors.affiliation: Departamento de Biologia &CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Sónia
authors.initials: S
authors.lastname: Cruz
authors.affiliation: MARE - Centro de Ciências do Mar e do Ambiente, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal.
authors.forename: Paulo
authors.initials: P
authors.lastname: Cartaxana
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Newcomer
authors.affiliation: 1] Departamento de Biologia &CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal [2] MARE - Centro de Ciências do Mar e do Ambiente, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal.
authors.forename: Gisela
authors.initials: G
authors.lastname: Dionísio
authors.affiliation: Departamento de Biologia &CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Calado
authors.affiliation: Departamento de Biologia &CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Serôdio
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.
authors.forename: Karen N
authors.initials: KN
authors.lastname: Pelletreau
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Rumpho
mesh_terms: D000818:Animals; D000460:Chlorophyta / Q000378:metabolism / Q000502:physiology; D002736:Chloroplasts / Q000378:metabolism / Q000502:physiology*; D008027:Light; D010788:Photosynthesis / Q000235:genetics*; D018087:Plastids / Q000235:genetics / Q000502:physiology; D013559:Symbiosis / Q000235:genetics / Q000502:physiology; D049871:Tritonia Sea Slug / Q000378:metabolism / Q000502:physiology*; D024341:Xanthophylls / Q000378:metabolism
chemical_list: D024341:Xanthophylls