title: Dietary carotenoids regulate astaxanthin content of copepods and modulate their susceptibility to UV light and copper toxicity.
abstract: High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal). Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC(50) values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers.
authors: Centre for Environmental Biology, Faculty of Sciences, University of Lisbon, Campo Grande C2, 1749-016 Lisbon, Portugal.
authors: Maria-José
authors: MJ
authors: Caramujo
authors: IBB-Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
authors: Carla C C R
authors: CCCR
authors: De Carvalho
authors: Departamento de Oceanologia y Ciencias Costeras, Instituto Venezolano de Investigaciones Científicas, Km 11 Carretera Panamericana, Altos de Pipe, Estado Miranda, Venezuela.
authors: Soraya J
authors: SJ
authors: Silva
authors: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
authors: Kevin R
authors: KR
authors: Carman
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000378:metabolism; D002338:Carotenoids / Q000008:administration & dosage* / Q000378:metabolism; D033342:Copepoda / Q000187:drug effects* / Q000378:metabolism*; D003300:Copper / Q000633:toxicity*; D003445:Crustacea / Q000378:metabolism; D004032:Diet; D005609:Free Radicals / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*; D024341:Xanthophylls / Q000378:metabolism
chemical_list: D005609:Free Radicals; D017382:Reactive Oxygen Species; D024341:Xanthophylls; D002338:Carotenoids; D003300:Copper; C005948:astaxanthine