Papers by Nunzia Elisabetta Melchiorre
Zenodo (CERN European Organization for Nuclear Research), Sep 6, 2022
Along the Italian coasts, toxins of algal origin in wild and cultivated shellfish have been repor... more Along the Italian coasts, toxins of algal origin in wild and cultivated shellfish have been reported since the 1970s. In this study, we used data gathered by the Veterinary Public Health Institutes and the Italian Environmental Health Protection Agencies from 2006 to 2019 to investigate toxicity events and relate them to the distribution of toxic species. Among detected toxins (OA and analogs, YTXs, PTXs, STXs, DAs, AZAs), OA and YTX were those most frequently reported in cases of seafood contamination. Levels of those toxins exceeding regulatory limits for OA were associated with high abundances of Dinophysis spp. and for YTX with blooms of Gonyaulax spinifera, Lingulodinium polyedra, and Protoceratium reticulatum. Seasonal blooms of Pseudo-nitzschia spp. occurred all along the Italian coast, but DA was only occasionally found in shellfish, at concentrations consistently below the regulatory limit. Alexandrium was recorded in many more areas than STXs, which only rarely exceeded the regulatory limit. Azadinium was sporadically recorded, and AZAs were sometimes detected in low quantities. Among the emerging toxins, PLTX-like toxins often accumulated in wild mussels and sea urchins due to the occurrences of Ostreopsis cf. ovata. Overall, Italian coastal waters harbour numerous potentially toxic species, with a few HAB hotspots related to DSP toxins. Still, rare cases of intoxications have occurred so far, reflecting the whole Mediterranean Sea conditions.
Weekly releases (1997–2007), 2006
In the summer of 2005, about 200 people who spent time on or near beaches in a stretch of the nor... more In the summer of 2005, about 200 people who spent time on or near beaches in a stretch of the northwest Italian coast around the city of Genova, sought medical treatment for
Marine Pollution Bulletin, 2008
Toxic harmful algal bloom (HAB) occurrence is becoming more frequent and problematic in highly ur... more Toxic harmful algal bloom (HAB) occurrence is becoming more frequent and problematic in highly urbanized coastal zones. In summer 2005 along the urbanized Genoa coastline (Ligurian Sea, North western Mediterranean Sea), local first aid stations treated about 200 people, who all showed similar symptoms following exposure to marine aerosols. The link with proliferation of Ostreopsis ovata was made, and it highlighted for the first time, the risks that benthic HABs may represent in highly urbanised temperate areas. Subsequently, a specific monitoring plan was designed and implemented in the same area in July 2006, before the first signs of Ostreopsis proliferation were detected. Here we report on this quantification of an Ostreopsis ovata bloom in the Ligurian Sea. Cells were quantified both in the water column and in the epiphytic community on macrophytes. Our results suggest a role of sea water temperature and weather conditions in favouring bloom development.
Journal of the American Society for Mass Spectrometry, 2008
Ecotoxicology and Environmental Safety, 2012
A series of 10 intra-laboratory bioassays and an inter-laboratory assay involving nine laboratori... more A series of 10 intra-laboratory bioassays and an inter-laboratory assay involving nine laboratories, were performed to validate the use of Amphibalanus amphitrite larvae as test organisms for ecotoxicological studies. The standardization protocol utilized Cadmium Nitrate as a reference toxicant and larval immobilization (after 24 and 48 h) as the end-point. The statistical data analysis showed high homogeneity in intra-laboratory EC 50 values among bioassay repetitions (coefficient of variation (CV)¼ 15.8% after 24 h and 16.9% after 48 h); also CV values obtained in inter laboratory comparison exercise were not higher than the 50%, variation coefficient mentioned in the ISO standards for the precision of inter-laboratory assays. The results demonstrated that the protocol implemented for the balanus larval bioassay comply with the international standards both for intra-and inter-laboratory precision.
Cryptogamie, Algologie, 2012
Inthe last decades, blooms of Ostreopsis ovata are increasingly frequent in several Mediterranean... more Inthe last decades, blooms of Ostreopsis ovata are increasingly frequent in several Mediterranean coastal areas, sometimes causing problems to the public health. The quantification of O. ovata abundances is generally performed by quantifying the number of cells per gram of macroalga, often preventing the comparison of abundances from different sites if cell quantifications are performed on different algal species. In this paper we propose as ampling method based on the use of am odified plastic syringe designed to quantify benthic cells abundances independently from the type of substratum. The method was tested in the O. ovata monitoring carried out in the Gulf of La Spezia (Ligurian Sea) and along the Apulian coasts (Southern Italy) since 2007. In 2009 the "syringe" method was compared with the classic methodology used in national monitoring of O. ovata.The syringe method seems interesting in terms of time costs and effectiveness, both for sample collection and processing, allowing quick and simple sampling of several sites along the coastline. The technique turned out to be adequate when afast and reliable estimate of O. ovata "reservoir" near the bottom was required, in order to forecast toxic algal blooms in coastal areas. Toxic dinoflagellates / Ostreopsis ovata/Monitoring /Sampling Methods
Analytical Chemistry, 2006
A new method for sensitive, specific, and direct determination of palytoxin is proposed herein. I... more A new method for sensitive, specific, and direct determination of palytoxin is proposed herein. It is based on combination of reversed-phase liquid chromatography with mass spectrometry (LC-MS). The new method was set up on a turbo ion spray-triple quadrupole MS instrument operating in selected ion monitoring (SIM) and multiple reaction monitoring (MRM) acquisition modes (positive ions). The minimum detection levels for matrix-free toxin on column were thus estimated from the data to be 200 and 125 pg in SIM and MRM modes, respectively. Spiking experiments before and after extraction allowed us to assess limits of detection and quantitation for palytoxin in matrix, accuracy, and intraday and interday reproducibility of the method. The developed method was decisive for the analysis of a plankton sample collected along Genoa coasts in July 2005 when respiratory illness in people exposed to marine aerosols occurred. It is suggested that putative palytoxin was the causative agent responsible for patients' symptoms and demonstrated for the first time the presence of such a toxin in Italian waters.
Analytical Biochemistry, 2008
A cytolytic assay that could detect palytoxin and its congeners has been developed by the use of ... more A cytolytic assay that could detect palytoxin and its congeners has been developed by the use of an established cell line grown as monolayer to replace the current hemolytic method. We used MCF-7 cells and cytolysis was measured by the release of cytosolic lactate dehydrogenase (LDH) in the buffer added to treated cells (culture supernatant). A dose-dependent increase in LDH activity in culture supernatants was detected when MCF-7 cells were exposed to palytoxin and its analogue ostreocin D. The cytolytic response induced by palytoxin and ostreocin D was specific for this group of compounds, acting on Na+/K+-ATPase, as it was prevented when cells were preincubated with ouabain. The specificity of our assay for palytoxin and its congeners was confirmed by the finding that cytolysis was not detected when MCF-7 cells were exposed to unrelated toxins such as maitotoxin, tetrodotoxin, okadaic acid, and yessotoxin, even in the case of compounds that elicit cytotoxic responses under our experimental conditions. Using extracts from biological materials after spiking with the palytoxin standard, we found a good correlation between palytoxin levels measured by our cytolytic assay and the expected values. Our cytolytic assay detected palytoxin in naturally contaminated materials, but estimates were significantly higher than the palytoxin contents determined by LC-MS, indicating that naturally contaminated materials contain biologically active palytoxin congeners. We conclude that our cytolytic assay based on the use of MCF-7 cell monolayers is a viable alternative to animal-based methods for the determination of palytoxin and its congeners in contaminated materials.
Analytical Biochemistry, 2008
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Papers by Nunzia Elisabetta Melchiorre