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https://darchive.mblwhoilibrary.org/bitstream/handle/1912/5118/1-s2.0-S1568988311001533-main.pdf

Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health

LELONG A., HEGARET H., SOUDANT P. AND BATES S.S. 2012. Pseudo-nitzschia (Bacillariophyceae) species, domoic acid and amnesic shellfish poisoning: revisiting previous paradigms. Phycologia 51: 168-216. DOI: 10.2216/11-37 Pseudo-nitzschia is a globally distributed diatom genus, some species of which produce domoic acid (DA), the neurotoxin that causes amnesic shellfish poisoning. This toxin killed at least three humans in 1987, launching numerous studies concerning the identification, distribution, ecology and physiology of Pseudo-nitzschia spp. Since previous reviews in 1998, knowledge has been gained about the fate of DA, including its accumulation by marine animals and its degradation by light and bacteria. Molecular techniques and more precise microscopy have enabled the description of new Pseudo-nitzschia species, 15 since 2002, including ones that are cryptic and pseudo-cryptic. An increasing number of the 37 identified species, including oceanic and coastal species, have been studied in laboratory culture. The sexual reproduction of 14 species has been documented. Fourteen species have now been shown to be toxigenic, although some strains are not always toxic under the testing conditions. The biotic and abiotic factors that modify DA production are reviewed, with a focus on how new discoveries have changed our original hypotheses about control mechanisms. Recent studies confirm that silicate and phosphate limitation trigger DA production. However, stress by low concentrations of iron or high concentrations of copper are newly discovered triggers, suggesting a trace-metal chelation role for DA. Organic sources of nitrogen (urea and glutamine), as well as changes in pH, CO2, salinity and bacterial concentration, also enhance DA production. Laboratory and field studies sometimes give divergent results for conditions that are conducive to toxin production. Gaps in knowledge include further information about the whole genome of Pseudo- nitzschia (including sexual stages), mechanisms of DA production and decline, presence or absence of a resting stage, heterotrophic ability, impact of viruses and fungi, and a more complete description of the ecological and physiological roles of DA.

Pseudo-nitzschia (Bacillariophyceae) species, domoic acid and amnesic shellfish poisoning: revisiting previous paradigms

Heavy metals are transferred from the abiotic environment to living organisms, accumulated in biota at different trophic levels, and thus contaminate the food chains/webs. Trophic transfer, bioaccu...

Trophic transfer, bioaccumulation, and biomagnification of non-essential hazardous heavy metals and metalloids in food chains/webs—Concepts and implications for wildlife and human health

Several Dinophysis species produce diarrhoetic toxins (okadaic acid and dinophysistoxins) and pectenotoxins, and cause gastointestinal illness, Diarrhetic Shellfish Poisoning (DSP), even at low cell densities (<103 cells·L−1). They are the main threat, in terms of days of harvesting bans, to aquaculture in Northern Japan, Chile, and Europe. Toxicity and toxin profiles are very variable, more between strains than species. The distribution of DSP events mirrors that of shellfish production areas that have implemented toxin regulations, otherwise misinterpreted as bacterial or viral contamination. Field observations and laboratory experiments have shown that most of the toxins produced by Dinophysis are released into the medium, raising questions about the ecological role of extracelular toxins and their potential uptake by shellfish. Shellfish contamination results from a complex balance between food selection, adsorption, species-specific enzymatic transformations, and allometric processes. Highest risk areas are those combining Dinophysis strains with high cell content of okadaates, aquaculture with predominance of mytilids (good accumulators of toxins), and consumers who frequently include mussels in their diet. Regions including pectenotoxins in their regulated phycotoxins will suffer from much longer harvesting bans and from disloyal competition with production areas where these toxins have been deregulated.

/pdf/dinophysis-toxins-causative-organisms-distribution-and-fate-1jd21t8ed2.pdf

Dinophysis Toxins: Causative Organisms, Distribution and Fate in Shellfish

Trace metal accumulation in different grain size fractions of the sediments from a semi-enclosed bay heavily contaminated by urban and industrial wastewaters

https://bib.irb.hr/datoteka/642589.1-s2.0-S0308814613013101-main1.pdf

As, Cd, Hg and Pb in four edible shellfish species from breeding and harvesting areas along the eastern Adriatic Coast, Croatia.

Biomonitoring of mercury in polluted coastal area using transplanted mussels

This is the first study that presents concentrations of domoic acid detected in the whole shellfish tissue from breeding and harvesting areas along the Croatian coast of the Adriatic Sea during the period 2006 to 2008. Shellfish sample analyses after SAX cleaning procedures, using a UV-DAD-HPLC system, showed the presence of domoic acid in four species. The most prevalent of those species were the blue mussel (Mytilus galloprovincialis), followed by European flat oyster (Ostrea edulis), Mediterranean scallop (Pecten jacobaeus) and proteus scallop (Flexopecten proteus). Domoic acid, a potentially lethal phycotoxin that causes amnesic shellfish poisoning (ASP), was detected for the first time in January 2006 with the highest value of 6.5486 μg g-1 in whole shellfish tissue. Pseudo-nitzschia spp. bloom events preceded these high domoic acid concentrations. According to this study, retention of domoic acid in the blue mussel M. galloprovincialis is more than 42 days. This investigation indicates the first presence of domoic acid in Croatian shellfish, but in concentrations under the regulatory limit (20 μg g-1), therefore shellfish consumption was not found to endanger human health.

https://www.mdpi.com/1420-3049/15/10/6835/pdf

Domoic acid--a new toxin in the Croatian Adriatic shellfish toxin profile.

Annual dynamics and ecological characteristics of the genus Dinophysis spp. and associated shellfish toxicity events were studied from 2001 to 2005 during monitoring fieldwork in the coastal waters of the eastern Adriatic Sea. Analysis of the seasonal occurrence of Dinophysis species identified D. acuminata and D. sacculus as typical spring species, D. caudata, D. fortii and D. rotundata as summer and late summer species and D. tripos as a winter species. The highest abundances occurred when there were large differences between surface and bottom temperatures and salinities. D. caudata, D. sacculus and D. rotundata abundances had significant relationships with Dt, while the highest abundances of D. acuta, D. fortii and D. tripos were associated with high Ds values. Much higher abundances of D. caudata and D. fortii in offshore compared to inshore waters of the northern Adriatic Sea and the significant inverse relationship of these species’ abundances with salinity suggested the possibility of their transport by Italian river-influenced coastal waters towards the eastern Croatian coast during the summer season and under stratified conditions. Toxicity events occurred more frequently in the more eutrophicated northern Adriatic Sea than in the southern Adriatic Sea and mostly succeeded the rainfall periods. Diarrhetic shellfish poisoning (DSP) toxin profile analyses identified okadaic acid and yessotoxin as the main DSP toxins occurring in Croatian waters.

/pdf/seasonal-variability-in-dinophysis-spp-abundances-and-3op6tbqbcn.pdf

Ivana Ujević

Papers

Trace metal accumulation in different grain size fractions of the sediments from a semi-enclosed bay heavily contaminated by urban and industrial wastewaters

As, Cd, Hg and Pb in four edible shellfish species from breeding and harvesting areas along the eastern Adriatic Coast, Croatia.

Biomonitoring of mercury in polluted coastal area using transplanted mussels

Domoic acid--a new toxin in the Croatian Adriatic shellfish toxin profile.

Seasonal variability in Dinophysis spp. abundances and diarrhetic shellfish poisoning outbreaks along the eastern Adriatic coast