1,721,014 research outputs found
Effects of Ostreopsis ovata (Dinophyceae) toxicity on Paracentrotus lividus development
No full textThe effects of Ostreopsis cfr. ovata clonal cultures towards the gametes and embryos of the sea urchin Paracentrotus lividus have been evaluated. The benthic dinoflagellate showed a significant toxicity towards sperms which have exhibited a drastic reduction of their fertility with the increasing of the microalgal concentration. A deleterious effect was also observed on the embryos cleavage. These data should be considered preliminary and will help us to better understand the effects that this allochtonous microalga might have on marine life in temperate waters
Toxicity assessment of Amphidinium carterae, Coolia cfr. monotis and Ostreopsis cfr. ovata (Dinophyta) isolated from the northern Ionian Sea (Mediterranean Sea)
Full text linkIn many coastal areas the abundant proliferation of microalgae producing biotoxins determines the occurrence of Harmful Algal Blooms (HABs). Their presence in temperate waters is well documented and often associated with marine toxin-derived disease. The occurrence and toxicity of three harmful microalgae (Amphidinium carterae, Coolia cfr. monotis and Ostreopsis cfr. ovata) from the northern Ionian Sea (Mediterranean Sea) is
hereby reported. The three dinoflagellates were sampled both on macroalgae and water and their morphology and occurrence were compared to those of other Mediterranean sites. The toxicity of the three cultured strains was tested by Artemia salina and hemolysis tests and their effects on the first stages of the sea urchin development was also evaluated.
The contemporary presence of the three species inhibited the in vitro sea urchin embryonic development. But this action could be ascribed to the sole Ostreopsis as the addition of the single species to the sea urchins embryos evidenced no effects in presence of Amphidinium or Coolia cells, and an irregular segmentation in presence of Ostreopsis. In particular, this
latter species exerted a cytotoxic effect in a dose-dependent manner, with a production of deformed embryos even at very low cell concentration (42 cells mL1). Nevertheless, when algal cell lysate was added, some effects on the sea urchin development was detected for each dinoflagellate, and also in this case Ostreopsis has proved to be the most toxic species.
However, the lysate of Amphidinium and Ostreopsis strongly affects the A. salina nauplii vitality, while the hemolytic activity was very low for Amphidinium and Coolia lysate and very strong for Ostreopsis.
Our results highlight the importance to monitoring the presence of these dinoflagellates whose effects may also be reflected on the early life stages of marine organisms, especially those species that are important from both an ecological and economic point of view, as the sea urchins are
I cianobatteri simbionti di Petrosia ficiformis (Porifera, Demospongiae) nel Mar Ionio settentrionale
No full textCaratterizzazione morfologica e molecolare di un cianobatterio isolato da Petrosia ficiformis (Porifera, Demospongiae)
No full textSponge-associated cyanobacterial diversity and activity: evidences from the northern Ionian Sea
No full textObservations of Spio decoratus (Polychaeta, Spionidae) life-history under laboratory conditions, with taxonomic considerations
No full textCytotoxic and antimitotic activities in aqueous extracts of eight cyanobacterial strains isolated from the marine sponge Petrosia ficiformis
No full textMarine cyanobacteria are photosynthetic prokaryotes of significant ecological interest, living free or in association with invertebrates. They are also considered as excellent sources of antineoplastic, antibacterial, antiviral and antifungal compounds. In this work, aqueous extracts from eight cyanobacterial strains isolated from the Mediterranean sponge Petrosia ficiformis have been investigated for their bioactive properties. Bioassays with human erythrocytes, Artemia salina nauplii, and Paracentrotus lividus gametes and embryos were performed. Some aqueous extracts exhibited citolytic effect on human erythrocytes and toxic activity against A. sauna nauplii. Furthermore antimitotic activity was evidenced during sea urchin embryos development and disorganization of blasto-meres with altered cell-cell contact was also induced. Some of the isolated cyanobacterial strains, belonging to Leptolyngbya and Synechococcus genera with an high citotoxic activity, should be further investigated to better characterize their bioactive molecules. Our data confirm cyanobacteria as an interesting source of novel bioactive compounds with potential applications in pharmaceutics
Dynamics of Dinophysis sensu lato species (Dinophyceae) in a coastal Mediterranean environment (Adriatic Sea)
No full textSpecies of Dinophysis Ehrenberg sensu lato were collected opportunistically along the southern Adriatic coasts (Apulia, Italy) during a survey of phytoplankton community structure and dynamics carried out from 1995 to 1997. Most previous reports of Dinophysis spp. in the Adriatic Sea concentrated on northern populations, with few data available on phytoplankton inhabiting the southern coastal areas. Thus, the present study is the first on Dinophysis sensu lato species composition and spatio-temporal distribution in these essentially oligotrophic waters. Twelve Dinophysis species were identified; some of which can be assigned to the genus Phalacroma. Dinophysis sacculus, D. fortii, D. caudata, Phalacroma rotundatum and P. mitra are potentially producers of diarrhetic shellfish poisoning. Seasonal changes in Dinophysis and Phalacroma populations are presented, as well as their relationships with hydrographic and biotic factors. These dinoflagellates were associated with mixing conditions, low water temperatures and high nutrient inputs. Furthermore, the statistical analysis evidenced significant correlations of Dinophysis species to chlorophyll a and phytoplankton. Ecological implications arising from the data are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved
On the presence of Phalacroma rotundatum in the southern Adriatic Sea (Italy)
Full text linkThe genus Dinophysis sensu lato is often involved in episodes of Diarrhetic Shellfish Poisoning (DSP) contaminations and human intoxications. To date, several species of this genus have shown toxin production in the laboratory; however, it is likely that many others could have this capability. Phalacroma rotundatum (Claparede and Lachmann) Kofoid and Michener, allocated by some authors to the genus Dinophysis, is a non-photosynthetic species, which has the potential to produce okadaic acid and its derivatives DTX-1 and DTX-2. This species was observed for the first time along the southern Adriatic coast of Puglia (Italy) during a 2 yr monitoring program on potentially toxic phytoplankton. P. rotundatum dynamics was studied in relation to hydrobiological conditions; its seasonal changes appeared rather independent from chemico-physical factors, but were significantly associated with those of phytoflagellates. A toxicity test (Microtox system) on P. rotundatum cells proved negative
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