Dinoflagellates belonging to the genus Ostreopsis are common members of benthic microalgal communities in both tropical and temperate areas. Several Ostreopsis species produce palytoxin (PTX) and its analogues, a class of highly potent toxins occurring in nature. The dangerous consequences of natural marine toxins can occur through phenomena of bioaccumulation through the food chain. PTX targets membrane sodium-potassium pumps (Na+/K+- ATPase), that is responsible for maintaining ionic gradients. Since the last few years, blooms of Ostreopsis ovata have been occurring in the Mediterranean region with increasing frequency, intensity and distribution causing, sometimes, mortality of benthic organisms and human health problems. In order to improve our knowledge about the effects of O. ovata toxicity directly on vertebrate marine organisms, such as/i.e. Sparus aurata, Dicentrarchus labrax and Argyrosomus regius, we performed an ecotoxicological screening by using a cultured strain of O. ovata, isolated from water samples collected at Isolabella (Ionian coast of Sicily) during a 2009-2010 study. Toxic effects on target tissues and organs (gills and liver) and the survivability of the organisms exposed to O. ovata cells were investigated, in experimental conditions at two different temperatures (20 and 25° C) and two different cell concentrations (105 cells L-1 and 106 cells L-1). Results indicated that the effects of O. ovata on the marine organisms tested in this study depend on the concentration of Ostreopsis living cells used for the experimental contamination, the higher temperature amplifying the fish responses. In all exposed fishes, a mechanical damage to the gills and consequent death were observed. Haemocyte aggregates surrounding both vegetative and encysted forms of O. ovata were evidenced in histological observations of gills. Epithelial hypertrophy, hyperplasia and secondary lamellar fusion have also been documented.
Tissue damages due to Ostreopsis ovata Fukuyo 1981 (Dinophyceae) in vertebrate marine organisms
2015
Abstract
Dinoflagellates belonging to the genus Ostreopsis are common members of benthic microalgal communities in both tropical and temperate areas. Several Ostreopsis species produce palytoxin (PTX) and its analogues, a class of highly potent toxins occurring in nature. The dangerous consequences of natural marine toxins can occur through phenomena of bioaccumulation through the food chain. PTX targets membrane sodium-potassium pumps (Na+/K+- ATPase), that is responsible for maintaining ionic gradients. Since the last few years, blooms of Ostreopsis ovata have been occurring in the Mediterranean region with increasing frequency, intensity and distribution causing, sometimes, mortality of benthic organisms and human health problems. In order to improve our knowledge about the effects of O. ovata toxicity directly on vertebrate marine organisms, such as/i.e. Sparus aurata, Dicentrarchus labrax and Argyrosomus regius, we performed an ecotoxicological screening by using a cultured strain of O. ovata, isolated from water samples collected at Isolabella (Ionian coast of Sicily) during a 2009-2010 study. Toxic effects on target tissues and organs (gills and liver) and the survivability of the organisms exposed to O. ovata cells were investigated, in experimental conditions at two different temperatures (20 and 25° C) and two different cell concentrations (105 cells L-1 and 106 cells L-1). Results indicated that the effects of O. ovata on the marine organisms tested in this study depend on the concentration of Ostreopsis living cells used for the experimental contamination, the higher temperature amplifying the fish responses. In all exposed fishes, a mechanical damage to the gills and consequent death were observed. Haemocyte aggregates surrounding both vegetative and encysted forms of O. ovata were evidenced in histological observations of gills. Epithelial hypertrophy, hyperplasia and secondary lamellar fusion have also been documented.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
