Distribution of Marine Lipophilic Toxins in Shellfish Products Collected from the Chinese Market

To investigate the prevalence of lipophilic marine biotoxins in shellfish from the Chinese market, we used hydrophilic interaction liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure levels of okadaic acid (OA), azaspiracid (AZA1), pectenotoxin (PTX2), gymnodimine (GYM), and spirolide (SPX1). We collected and analyzed 291 shellfish samples from main production sites along a wide latitudinal transect along the Chinese coastline from December 2008 to December 2009. Results revealed a patchy distribution of the five toxins and highlighted the specific geographical distribution and seasonal and species variation of the putative toxigenic organisms. All five lipophilic marine biotoxins were found in shellfish samples. The highest concentrations of OA, AZA1, PTX2, GYM, and SPX1 were 37.3, 5.90, 16.4, 14.4, and 8.97 μg/kg, respectively. These values were much lower than the legislation limits for lipophilic shellfish toxins. However, the value might be significantly underestimated for the limited detection toxins. Also, these toxins were found in most coastal areas of China and were present in almost all seasons of the year. Thus, these five toxins represent a potential threat to human health. Consequently, studies should be conducted and measures should be taken to ensure the safety of the harvested product.     

Occurrence of Lipophilic Marine Toxins in Shellfish from Galicia (NW of Spain) and Synergies among Them

Lipophilic marine toxins pose a serious threat for consumers and an enormous economic problem for shellfish producers. Synergistic interaction among toxins may play an important role in the toxicity of shellfish and consequently in human intoxications. In order to study the toxic profile of molluscs, sampled during toxic episodes occurring in different locations in Galicia in 2014, shellfish were analyzed by liquid chromatography tandem mass spectrometry (LC–MS/MS), the official method for the detection of lipophilic toxins. The performance of this procedure was demonstrated to be fit for purpose and was validated in house following European guidelines. The vast majority of toxins present in shellfish belonged to the okadaic acid (OA) group and some samples from a particular area contained yessotoxin (YTX). Since these toxins occur very often with other lipophilic toxins, we evaluated the potential interactions among them. A human neuroblastoma cell line was used to study the possible synergies of OA with other lipophilic toxins. Results show that combination of OA with dinophysistoxin 2 (DTX2) or YTX enhances the toxicity triggered by OA, decreasing cell viability and cell proliferation, depending on the toxin concentration and incubation time. The effects of other lipophilic toxins as 13-desmethyl Spirolide C were also evaluated in vitro.     

Monitoring the Emergence of Algal Toxins in Shellfish: First Report on Detection of Brevetoxins in French Mediterranean Mussels

In France, four groups of lipophilic toxins are currently regulated: okadaic acid/dinophysistoxins, pectenotoxins, yessotoxins and azaspiracids. However, many other families of toxins exist, which can be emerging toxins. Emerging toxins include both toxins recently detected in a specific area of France but not regulated yet (e.g., cyclic imines, ovatoxins) or toxins only detected outside of France (e.g., brevetoxins). To anticipate the introduction to France of these emerging toxins, a monitoring program called EMERGTOX was set up along the French coasts in 2018. The single-laboratory validation of this approach was performed according to the NF V03-110 guidelines by building an accuracy profile. Our specific, reliable and sensitive approach allowed us to detect brevetoxins (BTX-2 and/or BTX-3) in addition to the lipophilic toxins already regulated in France. Brevetoxins were detected for the first time in French Mediterranean mussels (Diana Lagoon, Corsica) in autumn 2018, and regularly every year since during the same seasons (autumn, winter). The maximum content found was 345 µg (BTX-2 + BTX-3)/kg in mussel digestive glands in November 2020. None were detected in oysters sampled at the same site. In addition, a retroactive analysis of preserved mussels demonstrated the presence of BTX-3 in mussels from the same site sampled in November 2015. The detection of BTX could be related to the presence in situ at the same period of four Karenia species and two raphidophytes, which all could be potential producers of these toxins. Further investigations are necessary to understand the origin of these toxins.     

Diarrhetic Shellfish Toxins and Other Lipophilic Toxins of Human Health Concern in Washington State

The illness of three people in 2011 after their ingestion of mussels collected from Sequim Bay State Park, Washington State, USA, demonstrated the need to monitor diarrhetic shellfish toxins (DSTs) in Washington State for the protection of human health. Following these cases of diarrhetic shellfish poisoning, monitoring for DSTs in Washington State became formalized in 2012, guided by routine monitoring of Dinophysis species by the SoundToxins program in Puget Sound and the Olympic Region Harmful Algal Bloom (ORHAB) partnership on the outer Washington State coast. Here we show that the DSTs at concentrations above the guidance level of 16 μg okadaic acid (OA) + dinophysistoxins (DTXs)/100 g shellfish tissue were widespread in sentinel mussels throughout Puget Sound in summer 2012 and included harvest closures of California mussel, varnish clam, manila clam and Pacific oyster. Concentrations of toxins in Pacific oyster and manila clam were often at least half those measured in blue mussels at the same site. The primary toxin isomer in shellfish and plankton samples was dinophysistoxin-1 (DTX-1) with D. acuminata as the primary Dinophysis species. Other lipophilic toxins in shellfish were pectenotoxin-2 (PTX-2) and yessotoxin (YTX) with azaspiracid-2 (AZA-2) also measured in phytoplankton samples. Okadaic acid, azaspiracid-1 (AZA-1) and azaspiracid-3 (AZA-3) were all below the levels of detection by liquid chromatography tandem mass spectrometry (LC-MS/MS). A shellfish closure at Ruby Beach, Washington, was the first ever noted on the Washington State Pacific coast due to DSTs. The greater than average Fraser River flow during the summers of 2011 and 2012 may have provided an environment conducive to dinoflagellates and played a role in the prevalence of toxigenic Dinophysis in Puget Sound.     

Report on the first detection of pectenotoxin-2, spirolide-a and their derivatives in French shellfish

In the context of the French Phytoplankton and Phycotoxins Monitoring Network (REPHY) programme, shellfish samples were harvested from different locations where harmful algae blooms were known to have occurred. For all shellfish samples found positive by the mouse bioassay for diarrhetic shellfish poisoning (DSP) toxins, liquid chromatography (LC) coupled with mass spectrometry (MS) was used to search for the following lipophilic toxins: okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs), azaspiracids (AZAs), yessotoxins (YTXs), spirolides (SPXs) and gymnodimines (GYMs). In order to investigate the presence of acyl-OAs and/or acyl-DTX-1,-2 (DTX-3), alkaline hydrolysis was performed on all samples, and LC/MS analyses were carried out on the samples before and after hydrolysis. The results revealed different lipophilic toxin profiles as a function of the shellfish sampling location. The primary finding was that all of the samples contained OA and acyl-OA. In addition, other lipophilic toxins were found in shellfish samples: DTX-2, acyl-DTX-2 and SPXs (SPX-A, SPX-desMeC) on the Atlantic coast (Southern Brittany, Arcachon), and pectenotoxins (PTX-2, PTX-2-seco-acid and 7-epi-PTX-2-seco-acid) on the Mediterranean coast (Thau lagoon, the island of Corsica). This paper reports on the first detection of PTX-2, SPX-A and their derivatives in French shellfish.     

Optimization and Validation of a High Throughput UHPLC-MS/MS Method for Determination of the EU Regulated Lipophilic Marine Toxins and Occurrence in Fresh and Processed Shellfish

Under the name of lipophilic marine toxins, there are included more than 1000 toxic secondary metabolites, produced by phytoplankton, with the common chemical property of lipophilicity. Due to toxicological effects and geographical distribution, in European legislation relevant compounds are regulated, and their determination is accomplished with the reference liquid chromatography-tandem mass spectrometry method. In this study a modified ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed for the identification and quantification of EU-regulated lipophilic toxins. The method optimization included a refinement of SPE-C18 clean-up, in order to reduce matrix interferences. Improved LC conditions and upgraded chromatographic ammonia-based gradient ensured the best separation of all analytes and, in particular, of the two structural isomers (OA and DTX2). Also, different MS parameters were tested, and confirmation criteria finally established. The validation studies confirmed that all parameters were satisfactory. The requirements for precision (RSD% < 11.8% for each compound), trueness (recoveries from 73 to 101%) and sensitivity (limits of quantification in the range 3–8 µg kg⁻¹) were fulfilled. The matrix effect, ranging from −9 to 19%, allowed the use of a calibration curve in solvent (3–320 µg kg⁻¹ in matrix) for quantification of real samples. Method relative uncertainty ranged from 12 to 20.3%. Additionally, a total of 1000 shellfish samples was analysed, providing a first preliminary surveillance study that may contribute to the knowledge of lipophilic marine toxins contamination. Increase in algae proliferation events and intoxication cases, EFSA suggestions for modification of maximum permitted levels and toxicity equivalency factors, and new studies of important toxic effects underline that implementation of reference methods still represents an important task for health and food safety laboratories.     

Lipophilic Toxins in Wild Bivalves from the Southern Gulf of California,Mexico

Most of the shellfish fisheries of Mexico occur in the Gulf of California. In this region, known for its high primary productivity, blooms of diatoms and dinoflagellates are common, occurring mainly during upwelling events. Dinoflagellates that produce lipophilic toxins are present, where some outbreaks related to okadaic acid and dinophisystoxins have been recorded. From January 2015 to November 2017 samples of three species of wild bivalve mollusks were collected monthly in five sites in the southern region of Bahía de La Paz. Pooled tissue extracts were analyzed using LC-MS/MS to detect lipophilic toxins. Eighteen analogs of seven toxin groups, including cyclic imines were identified, fortunately individual toxins did not exceed regulatory levels and also the total toxin concentration for each bivalve species was lower than the maximum permitted level for human consumption. Interspecific differences in toxin number and concentration were observed in three species of bivalves even when the samples were collected at the same site. Okadaic acid was detected in low concentrations, while yessotoxins and gymnodimines had the highest concentrations in bivalve tissues. Although in low quantities, the presence of cyclic imines and other lipophilic toxins in bivalves from the southern Gulf of California was constant.     

Phytoplankton Toxins and Their Potential Therapeutic Applications: A Journey toward the Quest for Potent Pharmaceuticals

Phytoplankton are prominent organisms that contain numerous bioactive substances and secondary metabolites, including toxins, which can be valuable to pharmaceutical, nutraceutical, and biotechnological industries. Studies on toxins produced by phytoplankton such as cyanobacteria, diatoms, and dinoflagellates have become more prevalent in recent years and have sparked much interest in this field of research. Because of their richness and complexity, they have great potential as medicinal remedies and biological exploratory probes. Unfortunately, such toxins are still at the preclinical and clinical stages of development. Phytoplankton toxins are harmful to other organisms and are hazardous to animals and human health. However, they may be effective as therapeutic pharmacological agents for numerous disorders, including dyslipidemia, obesity, cancer, diabetes, and hypertension. In this review, we have focused on the properties of different toxins produced by phytoplankton, as well as their beneficial effects and potential biomedical applications. The anticancer properties exhibited by phytoplankton toxins are mainly attributed to their apoptotic effects. As a result, phytoplankton toxins are a promising strategy for avoiding postponement or cancer treatment. Moreover, they also displayed promising applications in other ailments and diseases such as Alzheimer’s disease, diabetes, AIDS, fungal, bacterial, schizophrenia, inflammation, allergy, osteoporosis, asthma, and pain. Preclinical and clinical applications of phytoplankton toxins, as well as future directions of their enhanced nano-formulations for improved clinical efficacy, have also been reviewed.     

Brevetoxin and Conotoxin Interactions with Single-Domain Voltage-Gated Sodium Channels from a Diatom and Coccolithophore

The recently characterized single-domain voltage-gated ion channels from eukaryotic protists (EukCats) provide an array of novel channel proteins upon which to test the pharmacology of both clinically and environmentally relevant marine toxins. Here, we examined the effects of the hydrophilic µ-CTx PIIIA and the lipophilic brevetoxins PbTx-2 and PbTx-3 on heterologously expressed EukCat ion channels from a marine diatom and coccolithophore. Surprisingly, none of the toxins inhibited the peak currents evoked by the two EukCats tested. The lack of homology in the outer pore elements of the channel may disrupt the binding of µ-CTx PIIIA, while major structural differences between mammalian sodium channels and the C-terminal domains of the EukCats may diminish interactions with the brevetoxins. However, all three toxins produced significant negative shifts in the voltage dependence of activation and steady state inactivation, suggesting alternative and state-dependent binding conformations that potentially lead to changes in the excitability of the phytoplankton themselves.     

Quantitation Overcoming Matrix Effects of Lipophilic Toxins in Mytilus galloprovincialis by Liquid Chromatography-Full Scan High Resolution Mass Spectrometry Analysis (LC-HR-MS)

The analysis of marine lipophilic toxins in shellfish products still represents a challenging task due to the complexity and diversity of the sample matrix. Liquid chromatography coupled with mass spectrometry (LC-MS) is the technique of choice for accurate quantitative measurements in complex samples. By combining unambiguous identification with the high selectivity of tandem MS, it provides the required high sensitivity and specificity. However, LC-MS is prone to matrix effects (ME) that need to be evaluated during the development and validation of methods. Furthermore, the large sample-to-sample variability, even between samples of the same species and geographic origin, needs a procedure to evaluate and control ME continuously. Here, we analyzed the toxins okadaic acid (OA), dinophysistoxins (DTX-1 and DTX-2), pectenotoxin (PTX-2), yessotoxin (YTX) and azaspiracid-1 (AZA-1). Samples were mussels (Mytilus galloprovincialis), both fresh and processed, and a toxin-free mussel reference material. We developed an accurate mass-extracted ion chromatogram (AM-XIC) based quantitation method using an Orbitrap instrument, evaluated the ME for different types and extracts of mussel samples, characterized the main compounds co-eluting with the targeted molecules and quantified toxins in samples by following a standard addition method (SAM). An AM-XIC based quantitation of lipophilic toxins in mussel samples using high resolution and accuracy full scan profiles (LC-HR-MS) is a good alternative to multi reaction monitoring (MRM) for instruments with HR capabilities. ME depend on the starting sample matrix and the sample preparation. ME are particularly strong for OA and related toxins, showing values below 50% for fresh mussel samples. Results for other toxins (AZA-1, YTX and PTX-2) are between 75% and 110%. ME in unknown matrices can be evaluated by comparing their full scan LC-HR-MS profiles with those of known samples with known ME. ME can be corrected by following SAM with AM-XIC quantitation if necessary.     

Characterization of intracellular and extracellular saxitoxin levels in both field and cultured Alexandrium spp. samples from Sequim Bay, Washington

Traditionally, harmful algal bloom studies have primarily focused on quantifying toxin levels contained within the phytoplankton cells of interest. In the case of paralytic shellfish poisoning toxins (PSTs), intracellular toxin levels and the effects of dietary consumption of toxic cells by planktivores have been well documented. However, little information is available regarding the levels of extracellular PSTs that may leak or be released into seawater from toxic cells during blooms. In order to fully evaluate the risks of harmful algal bloom toxins in the marine food web, it is necessary to understand all potential routes of exposure. In the present study, extracellular and intracellular PST levels were measured in field seawater samples (collected weekly from June to October 2004–2007) and in Alexandrium spp. culture samples isolated from Sequim Bay, Washington. Measurable levels of intra- and extra-cellular toxins were detected in both field and culture samples via receptor binding assay (RBA) and an enzyme-linked immunosorbent assay (ELISA). Characterization of the PST toxin profile in the Sequim Bay isolates by pre-column oxidation and HPLC-fluorescence detection revealed that gonyautoxin 1 and 4 made up 65 ± 9.7 % of the total PSTs present. Collectively, these data confirm that extracellular PSTs are present during blooms of Alexandrium spp. in the Sequim Bay region.     

Detection of Diarrheic Shellfish Poisoning and Azaspiracid Toxins in Moroccan Mussels: Comparison of the LC-MS Method with the Commercial Immunoassay Kit

Diarrheic shellfish poisoning (DSP) is a recurrent gastrointestinal illness in Morocco, resulting from consumption of contaminated shellfish. In order to develop a rapid and reliable technique for toxins detection, we have compared the results obtained by a commercial immunoassay-“DSP-Check” kit” with those obtained by LC-MS. Both techniques are capable of detecting the toxins in the whole flesh extract which was subjected to prior alkaline hydrolysis in order to detect simultaneously the esterified and non esterified toxin forms. The LC-MS method was found to be able to detect a high level of okadaic acid (OA), low level of dinophysistoxin-2 (DTX2), and surprisingly, traces of azaspiracids 2 (AZA2) in mussels. This is the first report of a survey carried out for azaspiracid (AZP) contamination of shellfish harvested in the coastal areas of Morocco. The “DSP-Check” kit was found to detect quantitatively DSP toxins in all contaminated samples containing only OA, provided that the parent toxins were within the range of detection and was not in an ester form. A good correlation was observed between the two methods when appropriate dilutions were performed. The immunoassay kit appeared to be more sensitive, specific and faster than LC-MS for determination of DSP in total shellfish extract.     

Persistent Contamination of Octopuses and Mussels with Lipophilic Shellfish Toxins during Spring Dinophysis Blooms in a Subtropical Estuary

This study investigates the occurrence of diarrhetic shellfish toxins (DSTs) and their producing phytoplankton species in southern Brazil, as well as the potential for toxin accumulation in co-occurring mussels (Perna perna) and octopuses (Octopus vulgaris). During the spring in 2012 and 2013, cells of Dinophysis acuminata complex were always present, sometimes at relatively high abundances (max. 1143 cells L⁻¹), likely the main source of okadaic acid (OA) in the plankton (max. 34 ng L⁻¹). Dinophysis caudata occurred at lower cell densities in 2013 when the lipophilic toxins pectenotoxin-2 (PTX-2) and PTX-2 seco acid were detected in plankton and mussel samples. Here, we report for the first time the accumulation of DSTs in octopuses, probably linked to the consumption of contaminated bivalves. Perna perna mussels were consistently contaminated with different DSTs (max. 42 µg kg⁻¹), and all octopuses analyzed (n = 5) accumulated OA in different organs/tissues: digestive glands (DGs) > arms > gills > kidneys > stomach + intestine. Additionally, similar concentrations of 7-O-palmytoyl OA and 7-O-palmytoly dinophysistoxin-1 (DTX-1) were frequently detected in the hepatopancreas of P. perna and DGs of O. vulgaris. Therefore, octopuses can be considered a potential vector of DSTs to both humans and top predators such as marine mammals.     

Lipophilic Toxins in Chile: History,Producers and Impacts

A variety of microalgal species produce lipophilic toxins (LT) that are accumulated by filter-feeding bivalves. Their negative impacts on human health and shellfish exploitation are determined by toxic potential of the local strains and toxin biotransformations by exploited bivalve species. Chile has become, in a decade, the world’s major exporter of mussels (Mytilus chilensis) and scallops (Argopecten purpuratus) and has implemented toxin testing according to importing countries’ demands. Species of the Dinophysis acuminata complex and Protoceratium reticulatum are the most widespread and abundant LT producers in Chile. Dominant D. acuminata strains, notwithstanding, unlike most strains in Europe rich in okadaic acid (OA), produce only pectenotoxins, with no impact on human health. Dinophysis acuta, suspected to be the main cause of diarrhetic shellfish poisoning outbreaks, is found in the two southernmost regions of Chile, and has apparently shifted poleward. Mouse bioassay (MBA) is the official method to control shellfish safety for the national market. Positive results from mouse tests to mixtures of toxins and other compounds only toxic by intraperitoneal injection, including already deregulated toxins (PTXs), force unnecessary harvesting bans, and hinder progress in the identification of emerging toxins. Here, 50 years of LST events in Chile, and current knowledge of their sources, accumulation and effects, are reviewed. Improvements of monitoring practices are suggested, and strategies to face new challenges and answer the main questions are proposed.     

Effects of Marine Toxins on the Reproduction and Early Stages Development of Aquatic Organisms

Marine organisms, and specially phytoplankton species, are able to produce a diverse array of toxic compounds that are not yet fully understood in terms of their main targets and biological function. Toxins such as saxitoxins, tetrodotoxin, palytoxin, nodularin, okadaic acid, domoic acid, may be produced in large amounts by dinoflagellates, cyanobacteria, bacteria and diatoms and accumulate in vectors that transfer the toxin along food chains. These may affect top predator organisms, including human populations, leading in some cases to death. Nevertheless, these toxins may also affect the reproduction of aquatic organisms that may be in contact with the toxins, either by decreasing the amount or quality of gametes or by affecting embryonic development. Adults of some species may be insensitive to toxins but early stages are more prone to intoxication because they lack effective enzymatic systems to detoxify the toxins and are more exposed to the toxins due to a higher metabolic growth rate. In this paper we review the current knowledge on the effects of some of the most common marine toxins on the reproduction and development of early stages of some organisms.     

Polymethoxy-1-alkenes from Aphanizomenon ovalisporum Inhibit Vertebrate Development in the Zebrafish (Danio rerio) Embryo Model

Cyanobacteria are recognized producers of a wide array of toxic or otherwise bioactive secondary metabolites. The present study utilized the zebrafish (Danio rerio) embryo as an aquatic animal model of vertebrate development to identify, purify and characterize lipophilic inhibitors of development (i.e., developmental toxins) from an isolate of the freshwater cyanobacterial species, Aphanizomenon ovalisporum.Bioassay-guided fractionation led to the purification, and subsequent chemical characterization, of an apparent homologous series of isotactic polymethoxy-1-alkenes (1–6), including three congeners (4–6) previously identified from the strain, and two variants previously identified from other species (2 and 3), as well as one apparently novel member of the series (1). Five of the PMAs in the series (1–5) were purified in sufficient quantity for comparative toxicological characterization, and toxicity in the zebrafish embryo model was found to generally correlate with relative chain length and/or methoxylation. Moreover, exposure of embryos to a combination of variants indicates an apparent synergistic interaction between the congeners. Although PMAs have been identified previously in cyanobacteria, this is the first report of their apparent toxicity. These results, along with the previously reported presence of the PMAs from several cyanobacterial species, suggest a possibly widespread distribution of the PMAs as toxic secondary metabolites and warrants further chemical and toxicological investigation.     

A Stable-Isotope Mass Spectrometry-Based Metabolic Footprinting Approach to Analyze Exudates from Phytoplankton

Phytoplankton exudates play an important role in pelagic ecology and biogeochemical cycles of elements. Exuded compounds fuel the microbial food web and often encompass bioactive secondary metabolites like sex pheromones, allelochemicals, antibiotics, or feeding attractants that mediate biological interactions. Despite this importance, little is known about the bioactive compounds present in phytoplankton exudates. We report a stable-isotope metabolic footprinting method to characterise exudates from aquatic autotrophs. Exudates from ¹³C-enriched alga were concentrated by solid phase extraction and analysed by high-resolution Fourier transform ion cyclotron resonance mass spectrometry. We used the harmful algal bloom forming dinoflagellate Alexandrium tamarense to prove the method. An algorithm was developed to automatically pinpoint just those metabolites with highly ¹³C-enriched isotope signatures, allowing us to discover algal exudates from the complex seawater background. The stable-isotope pattern (SIP) of the detected metabolites then allowed for more accurate assignment to an empirical formula, a critical first step in their identification. This automated workflow provides an effective way to explore the chemical nature of the solutes exuded from phytoplankton cells and will facilitate the discovery of novel dissolved bioactive compounds.     

Toxin levels and profiles in microalgae from the north-Western Adriatic Sea--15 years of studies on cultured species

The Northern Adriatic Sea is the area of the Mediterranean Sea where eutrophication and episodes related to harmful algae have occurred most frequently since the 1970s. In this area, which is highly exploited for mollusk farming, the first occurrence of human intoxication due to shellfish consumption occurred in 1989, nearly 10 years later than other countries in Europe and worldwide that had faced similar problems. Until 1997, Adriatic mollusks had been found to be contaminated mostly by diarrhetic shellfish poisoning toxins (i.e., okadaic acid and dinophysistoxins) that, along with paralytic shellfish poisoning toxins (i.e., saxitoxins), constitute the most common marine biotoxins. Only once, in 1994, a toxic outbreak was related to the occurrence of paralytic shellfish poisoning toxins in the Adriatic coastal waters. Moreover, in the past 15 years, the Adriatic Sea has been characterized by the presence of toxic or potentially toxic algae, not highly widespread outside Europe, such as species producing yessotoxins (i.e., Protoceratium reticulatum, Gonyaulax spinifera and Lingulodinium polyedrum), recurrent blooms of the potentially ichthyotoxic species Fibrocapsa japonica and, recently, by blooms of palytoxin-like producing species of the Ostreopsis genus. This review is aimed at integrating monitoring data on toxin spectra and levels in mussels farmed along the coast of the Emilia-Romagna region with laboratory studies performed on the species involved in the production of those toxins; toxicity studies on toxic or potentially toxic species that have recently appeared in this area are also reviewed. Overall, reviewed data are related to: (i) the yessotoxins producing species P. reticulatum, G. spinifera and L. polyedrum, highlighting genetic and toxic characteristics; (ii) Adriatic strains of Alexandrium minutum, Alexandrium ostenfeldii and Prorocentrum lima whose toxic profiles are compared with those of strains of different geographic origins; (iii) F. japonica and Ostreopsis cf. ovata toxicity. Moreover, new data concerning domoic acid production by a Pseudo-nitzschia multistriata strain, toxicity investigations on a Prorocentrum cf. levis, and on presumably ichthyotoxic species, Heterosigma akashiwo and Chattonella cf. subsalsa, are also reported.     

西藏高原主要麦类作物真菌毒素污染与产毒真菌分布研究

为探明西藏麦类作物中真菌毒素污染程度及产毒真菌种类与分布,以青稞、小麦为研究对象,对其籽粒中多种毒素进行分析,并对毒素污染阳性样品进行真菌分离鉴定。结果表明,2018年毒素总检出率为20.13%;杂色曲霉毒素检出率最高,为10.74%;OTA超标率最高,为3.36%;小麦的毒素检出率和超标率都高于青稞,二者的污染毒素种类以OTA、ZEN、ST为主。西藏高原42份被真菌毒素污染的农作物籽粒中共分离到199份真菌,分属23属67种真菌,青霉属为优势属,曲霉属次之。     

Cysteinolic Acid Is a Widely Distributed Compatible Solute of Marine Microalgae

Phytoplankton rely on bioactive zwitterionic and highly polar small metabolites with osmoregulatory properties to compensate changes in the salinity of the surrounding seawater. Dimethylsulfoniopropionate (DMSP) is a main representative of this class of metabolites. Salinity-dependent DMSP biosynthesis and turnover contribute significantly to the global sulfur cycle. Using advanced chromatographic and mass spectrometric techniques that enable the detection of highly polar metabolites, we identified cysteinolic acid as an additional widely distributed polar metabolite in phytoplankton. Cysteinolic acid belongs to the class of marine sulfonates, metabolites that are commonly produced by algae and consumed by bacteria. It was detected in all dinoflagellates, haptophytes, diatoms and prymnesiophytes that were surveyed. We quantified the metabolite in different phytoplankton taxa and revealed that the cellular content can reach even higher concentrations than the ubiquitous DMSP. The cysteinolic acid concentration in the cells of the diatom Thalassiosira weissflogii increases significantly when grown in a medium with elevated salinity. In contrast to the compatible solute ectoine, cysteinolic acid is also found in high concentrations in axenic algae, indicating biosynthesis by the algae and not the associated bacteria. Therefore, we add this metabolite to the family of highly polar metabolites with osmoregulatory characteristics produced by phytoplankton.