title: Effects of harmful dinoflagellate Ostreopsis cf. ovata exposure on immunological, histological and oxidative responses of mussels Mytilus galloprovincialis.
abstract: In the last decade massive blooms of the Ostreopsis cf. ovata have occurred in the Mediterranean basin, posing great concern to both environmental and human health. Biotoxicological and chemical studies demonstrated that O. cf. ovata produces palytoxin and ovatoxins; besides direct respiratory effects on humans due to inhalation of marine toxic aerosols, O. cf. ovata blooms can cause adverse effects on benthic invertebrates. The main aim of this study was to highlight the role of immunological, cellular and oxidative mechanisms in modulating the toxicity induced by O. cf. ovata in mussels Mytilus galloprovincialis. Organisms were exposed in laboratory condition to O. cf. ovata and analysed after 7 and 14 days of exposure. Obtained results demonstrated a clear involvement of the immune system with a significant decrement of granulocytes respect to the hyalinocytes type cells, a diminished phagocytosis activity and a reduced lysosomal membrane stability in haemocytes, after both 7 and 14 days of exposure. Histological analyses showed a decrease of the digestive gland wall thickness, dilatation of the tubules, haemocytes infiltration into the digestive gland and a decrement of neutral lipid levels in exposed mussels; similar results suggest a possible inhibition of the feeding activity, with a consequent induction of authophagic phenomena and utilization of stored reserve products such as neutral lipids. Antioxidant parameters revealed a limited role of O. cf. ovata to induce oxidative stress in mussels exposed under laboratory conditions excepting for a certain increase of catalase, glutathione reductase and glutathione peroxidases activities, and a significantly higher capability to neutralize peroxyl radicals in mussels exposed for 14 days. Although the obtained results suggest a non-specific response of mussels to the O. cf. ovata exposure, observed effects on the general health status of exposed mussels should be adequately considered when assessing the ecological relevance of these algal blooms.
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy. s.gorbi@univpm.it
authors.forename: S
authors.initials: S
authors.lastname: Gorbi
authors.forename: G C
authors.initials: GC
authors.lastname: Avio
authors.forename: M
authors.initials: M
authors.lastname: Benedetti
authors.forename: C
authors.initials: C
authors.lastname: Totti
authors.forename: S
authors.initials: S
authors.lastname: Accoroni
authors.forename: S
authors.initials: S
authors.lastname: Pichierri
authors.forename: S
authors.initials: S
authors.lastname: Bacchiocchi
authors.forename: R
authors.initials: R
authors.lastname: Orletti
authors.forename: T
authors.initials: T
authors.lastname: Graziosi
authors.forename: F
authors.initials: F
authors.lastname: Regoli
mesh_terms: D000818:Animals; D001681:Biological Assay; D004141:Dinoflagellida / Q000502:physiology*; D006790:Host-Parasite Interactions; D008387:Marine Toxins / Q000633:toxicity; D051379:Mice; D049878:Mytilus / Q000276:immunology* / Q000469:parasitology* / Q000502:physiology
chemical_list: D008387:Marine Toxins
keywords: Antioxidant response; Haemocytes; Immune response; Mytilus galloprovincialis; Ostreopsis cf. ovata