Optimisation of Isolation Methods for the AZA Group of Marine Biotoxins and the Development of Accurate and Precise Methods of Analysis

The two main groups of biotoxins which affect the Irish shellfish industry are azaspiracids (AZAs) and the okadaic acid (OA) group (OA, DTX2, DTX1 and their esters) toxins. Since AZAs were first identified in 1998, well over 30 analogues have been reported. Structural and toxicological data have been described for AZA1–5 (isolated from shellfish). LC-MS/MS is the EU reference method for detection of the AZAs (AZA1, -2 and -3) and the OA group toxins in raw shellfish with the regulatory limit set at 160 μg/kg for each toxin group. Limited supplies of purified toxins for certified reference materials (CRMs) were available for AZA1−3. Little knowledge was also available on the relevance of the additional AZA analogues that had been reported, in terms of human health protection. The analysis of marine biotoxins by LC-MS/MS can be severely affected by matrix interferences. Here, a study was performed on two instruments; a quadrapole time of flight (QToF) and a triple stage quadrupole (TSQ) to assess matrix interferences for AZA1 and OA using a number of tissue types. Enhancement was observed for OA on the QToF while matrix suppression was observed for AZA1 on TSQ. The enhancement on the QToF was overcome by use of an on-line SPE method and matrix matched calibrants, while the suppression on the TSQ was found to be due to late eluting compounds from previous injections and was overcome by employing either a column flush method or an alkaline mobile phase. The isolation of 11 AZA analogues (AZA1−10 and 37-epi-AZA1) from shellfish using an improved procedure (7 steps) is described. Recoveries increased ~2-fold (~ 52%) from previously described isolation procedures. The preparative isolation procedure developed for shellfish was optimised for Azadinium spinosum bulk culture extracts such that only four steps were necessary to obtain purified AZA1 and -2. A purification efficiency of ~70% was achieved, and isolation from 1,200 L of culture yielded 9.3 mg of AZA1 and 2.2 mg of AZA2 (purities \u3e95%)

Predicting hospital aggression in secure psychiatric care

Risk assessment instruments have become a preferred means for predicting future aggression, claiming to predict long-term aggression risk. We investigate the predictive value over 12 months and 4 years of two commonly applied instruments (HCR-20, VRAG) in a secure psychiatric population with personality disorder. Focus was on aggression in hospital. The actuarial risk assessment (VRAG) was generally performing better than the structured risk assessment (HCR-20), although neither approach performed particularly well overall. Any value in their predictive potential appeared focused on the longer time period under study (4 years) and was specific to certain types of aggression. The value of these instruments for assessing aggression in hospital among personality-disordered patients in a high secure psychiatric setting is considered

Detection of azaspiracids in mussels using electrochemical immunosensors for fast screening in monitoring programs

Given the widespread occurrence of azaspiracids (AZAs), it is clearly necessary to advance in simple and low-cost methods for the rapid detection of these marine toxins in order to protect seafood consumers. To address this need, electrochemical immunosensors for the detection of AZAs based on a competitive direct immunoassay using peroxidase-labelled AZA as a tracer were developed. An anti-AZA polyclonal antibody was immobilised in a controlled and stable manner on protein G or avidin-coated electrodes. Experimental conditions were first optimised using colorimetric immunoassays on microtitre plates, providing intermediate products already applicable to the accurate detection of AZAs. Then, transfer of the protein G and avidin–biotin interaction-based immunoassays to 8-electrode arrays provided compact and miniaturised devices for the high-throughput detection of AZAs. The low amounts of immunoreagents required as well as the potential for reusability of the avidin–biotin interaction-based immunosensors represented significant economic savings as well as a contribution to sustainability. The electrochemical immunosensors enabled the quantification of all regulated AZAs below the regulatory limit, as well as a broad range of other toxic AZA analogues (from 63 ± 3 to 2841 ± 247 μg AZA-1 equiv./kg for the protein G-based immunosensor and from 46 ± 2 to 3079 ± 358 μg AZA-1 equiv./kg for the avidin–biotin interaction-based immunosensor). The good agreement between the results obtained by the immunosensors and LC–MS/MS in the analysis of naturally contaminated mussel samples demonstrated the easy implementation of electrochemical immunosensors for routine analysis of AZAs in food safety monitoring programs.info:eu-repo/semantics/acceptedVersio

Effects of Temperature, Growth Media, and Photoperiod on Growth and Toxin Production of Azadinium spinosum

Azaspiracids (AZAs) are microalgal toxins that can accumulate in shellfish and lead to human intoxications. To facilitate their study and subsequent biomonitoring, purification from microalgae rather than shellfish is preferable; however, challenges remain with respect to maximizing toxin yields. The impacts of temperature, growth media, and photoperiod on cell densities and toxin production in Azadinium spinosum were investigated. Final cell densities were similar at 10 and 18 ◦C, while toxin cell quotas were higher (~3.5-fold) at 10 ◦C. A comparison of culture media showed higher cell densities and AZA cell quotas (2.5–5-fold) in f10k compared to f/2 and L1 media. Photoperiod also showed differences, with lower cell densities in the 8:16 L:D treatment, while toxin cell quotas were similar for 12:12 and 8:16 L:D treatments but slightly lower for the 16:8 L:D treatment. AZA1, -2 and -33 were detected during the exponential phase, while some known and new AZAs were only detected once the stationary phase was reached. These compounds were additionally detected in field water samples during an AZA event

Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: An in vitro digestion approach

This study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood.info:eu-repo/semantics/acceptedVersio

Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: an in vitro digestion approach

This study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood.FCT - PD/BD/113484/2015info:eu-repo/semantics/publishedVersio

AZASPIRACIDS – Toxicological Evaluation, Test Methods and Identifcation of the Source Organisms (ASTOX II)

Since the Irish monitoring program was set up in 2001 azaspiracids (AZAs) have been detected in shellfish above the regulatory limit every year with the exception of 2004. The south west coast of Ireland is especially prone to the onsets of AZA events. Over this period a number of poisoning incidents associated with this toxin group have occurred, all related to Irish shellfish. In 2003 the Marine Institute was awarded funding for a research project named ASTOX. This project was very successful in producing a range of reference materials (RMs, which are essential for accurate detection and monitoring, and which up to this point were unavailable. The project also examined the toxicity of AZAs, primarily using in vitro cell assays but some in vivo studies were also performed. The overall aims of the ASTOX 2 project were to strengthen knowledge on the causative organism and toxicity of AZAs. The project aims were grouped into three areas: ecology, chemical support and toxicology.Marine Institute Marine Research Sub Programme (NDP 2007 - 2013), co financed under the European Regional Development Fund

Strategies for the elimination of matrix effects in the liquid chromatography tandem mass spectrometry analysis of the lipophilic toxins okadaic acid and azaspiracid-1 in molluscan shellfish

NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Chromatography A. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Chromatography A, [Volume 1217, Issue 45 (5 November 2010)] doi:10.1016/j.chroma.2010.09.020 http://www.sciencedirect.com/science/article/pii/S0021967310012409peer-reviewedConsiderable efforts are being made worldwide to replace in vivo assays with instrumental methods of analysis for the monitoring of marine biotoxins in shellfish. Analysis of these compounds by the preferred technique of LC-MS/MS is challenged by matrix effects associated with shellfish tissue components. In methods validation, assessment of matrix interferences is imperative to ensure the accuracy of analytical results. We evaluated matrix interferences in the analysis of okadaic acid (OA) and azaspiracid 1 (AZA1) in mollucscan shellfish by using a conventional acidic method on electrospray triple stage quadrapole (TSQ) and hybrid quadrupole time of flight (QToF) instruments, with matrix matched standards for several species. Using the acidic method, we found no matrix interferences for OA, and matrix suppression for AZA1, with the TSQ instrument; in contrast, we found matrix enhancement for OA, and no matrix interference for AZA1, with QToF. The suppression of AZA1 signal on the TSQ instrument was due to interfering compounds carried over from previous injections. The degree of suppression was dependent on the tissue type, ranging from 20 to 70%. Several strategies were evaluated to eliminate these interferences, including the partitioning of the extract with hexane, optimization of the chromatographi