Shellfish Tissue Research Articles

Spatiotemporal patterns of paralytic shellfish toxins and their relationships with environmental variables in British Columbia, Canada from 2002 to 2012

BackgroundHarmful algal blooms produce paralytic shellfish toxins that accumulate in the tissues of filter feeding shellfish. Ingestion of these toxic shellfish can cause a serious and potentially fatal condition known as paralytic shellfish poisoning (PSP). The coast of British Columbia is routinely monitored for shellfish toxicity, and this study uses data from the monitoring program to identify spatiotemporal patterns in shellfish toxicity events and their relationships with environmental variables. MethodsThe dinoflagellate genus Alexandrium produces the most potent paralytic shellfish toxin, saxitoxin (STX). Data on all STX measurements were obtained from 49 different shellfish monitoring sites along the coast of British Columbia for 2002–2012, and monthly toxicity events were identified. We performed hierarchical cluster analysis to group sites that had events in similar areas with similar timing. Machine learning techniques were used to model the complex relationships between toxicity events and environmental variables in each group. ResultsThe Strait of Georgia and the west coast of Vancouver Island had unique toxicity regimes. Out of the seven environmental variables used, toxicity in each cluster could be described by multivariable models including monthly sea surface temperature, air temperature, sea surface salinity, freshwater discharge, upwelling, and photosynthetically active radiation. The sea surface salinity and freshwater discharge variables produced the strongest univariate models for both geographic areas. ConclusionsApplying these methods in coastal regions could allow for the prediction of shellfish toxicity events by environmental conditions. This has the potential to optimize biotoxin monitoring, improve public health surveillance, and engage the shellfish industry in helping to reduce the risk of PSP.

The role of a PSP-producing Alexandrium bloom in an unprecedented diamondback terrapin (Malaclemys terrapin) mortality event in Flanders Bay, New York, USA

Diamondback terrapins (Malaclemys terrapin) are a threatened or endangered species in much of their range along the U.S. Atlantic and Gulf coasts. Over an approximately three-week period from late April to mid-May 2015, hundreds of adult diamondback terrapins were found dead on the shores of Flanders Bay, Long Island, New York, USA. Concurrent with the mortality event, elevated densities of the paralytic shellfish toxin (PST)-producing dinoflagellate, Alexandrium fundyense (>104 cells L−1) and high levels of PST in bivalves (maximal levels = 540 μg STX eq. 100 g−1 shellfish tissue) were observed in the Flanders Bay region, resulting in shellfish bed closures in regional tributaries. Gross and histologic postmortem examinations of terrapins revealed no physical trauma to individuals or a common, underlying disease process to explain the deaths. PST compounds (0.2–12.5 μg STX eq. 100 g−1) were present in various M. terrapin tissues collected over the duration of the mortality event. High-throughput sequencing revealed that the ribbed mussel (Geukensia demissa, a PST vector) was present in the gastrointestinal tracks of all terrapin samples tested. While the potential of PST to cause mortality in chelonians has not been well-characterized, in the absence of other significant findings from necropsies and pathological analyses, we provide evidence that PST in shellfish was likely high enough to cause or contribute to the mortality in these small (<2.0 kg) animals.

Distribution of uronic acid-containing polysaccharides in 5 species of shellfishes

Mollusks are a rich source of uronic acid-containing polysaccharides (UACPs) possessing biological and pharmacological activities. In the present study, UACP compositions of different tissues from 5 species of edible shellfishes, namely Neverita didyma, Natica janthostomoides, Saxidomus purpurata, Cyclina sinensis, and Chlamys farreri were systemically analyzed. Totally 10 UACPs were observed, including chondroitin sulfate, heparin, an identified mannoglucuronan, 3 unknown glycosaminoglycans (GAGs, U1, U3 and U6) with hexuronic acid-hexosamine repeating units, and 4 unknown non-GAGs (U2, U4, U5 and U7) with hexuronic acid-hexose repeating units. U4-7 showed tissue- and species-specificity while the other UACPs prevalently existed in these shellfish tissues. UACP compositions in tissues from the same shellfish species were similar for S. purpurata and C. sinensis but different for C. farreri, N. didyma and N. janthostomoides. And this investigation also indicates that the similarity of UACPs composition between different shellfishes is related to the genetic relationship.

Biomonitoring Selected Heavy Metal Concentration in Nerita Sp. Collected from Tanjung Lumpur Mangrove Forest

Environmental pollution by heavy metals is a serious threat to human and ecosystem. Accumulation of heavy metals in the biota may pose hazardous impact on public health and other living organisms. By using gastropods Neritasp as bio-indicator, the levels of heavy metals in their soft tissues can determine the contamination of heavy metals in the Tanjung Lumpur Mangrove along the Kuantan River. The aim of this study is to identify copper, cadmium, chromium and iron accumulated in the tissue of Neritasp, to investigate the concentration of the copper, cadmium, chromium and iron in the molluscan tissue among the different sizes of gastropod Neritaspand to compare the concentrations of heavy metals in a gastropod Neritasp tissue among the different stations of Kuantan River, Pahang. Gastropods of Neritasp were randomly collected along the river. The tissues of gastropods were digested with nitric acid. Then, concentration of copper, cadmium, chromium and iron were analyzed by using flame atomic absorption spectrophotometer (AAS) model Perkin Elmer SIMAA 6100 graphite furnace. Neritasp accumulate copper the most in their tissues compared to other heavy metals. The concentrations are around 189.8 µg/ L – 247.95 µg/ L. The highest concentration of copper is in Station 3 which is at 241.67 µg/ L. The second highest concentration is iron or ferrum where the concentrations are around 121.25 µg/ L – 174.55 µg/ L. Station 3 was identified to have the highest concentration of iron at 161.12 µg/ L. Followed by, chromium which the concentrations are around 23.49 µg/ L – 46.15 µg/ L. The highest concentration of chromium is Station 1 at 34.82 µg/ L. The lowest concentration of heavy metals is cadmium which is around 8.69 µg/ L – 18.46 µg/ L. Also, Station 1 showed the highest concentration of cadmium at 17.56 µg/ L. This study can be used to identify contamination of heavy metals in marine zone by using bio-indicator to avoid environmental perturbation.

Concentrations of Heavy Metals in Edible Dominant Oyster (Saccostreacucullata) Inhabiting Sagar Island, West Bengal

The heavy metals from the ambient environment enter the tissues of marine molluscs very frequently as they feed on the plankton of marine and estuarine water. Sagar island, situated in the northeast coast of Bay of Bengal, is the habitat of three major species of oysters namely Saccostrea cucullata, Crassostrea cuttackensis and Crassostrea madrasensis. By virtue of their sedentary nature, these species are exposed to all categories of pollutants, which have put them in the domain of indicator species. In this present paper, the concentrations of zinc, copper and lead were assessed in Saccostrea cucullata inhabiting Sagar island, Indian Sundarbans. A unique seasonal variation is observed in the accumulation of the selected heavy metals. A more detailed study is needed to establish the species as indicator of heavy metals.

An Antarctic molluscan biomineralisation tool-kit

The Antarctic clam Laternula elliptica lives almost permanently below 0 °C and therefore is a valuable and tractable model to study the mechanisms of biomineralisation in cold water. The present study employed a multidisciplinary approach using histology, immunohistochemistry, electron microscopy, proteomics and gene expression to investigate this process. Thirty seven proteins were identified via proteomic extraction of the nacreous shell layer, including two not previously found in nacre; a novel T-rich Mucin-like protein and a Zinc-dependent metalloprotease. In situ hybridisation of seven candidate biomineralisation genes revealed discrete spatial expression patterns within the mantle tissue, hinting at modular organisation, which is also observed in the mantle tissues of other molluscs. All seven of these biomineralisation candidates displayed evidence of multifunctionality and strong association with vesicles, which are potentially involved in shell secretion in this species.

Laser ablation electrospray ionization high-resolution mass spectrometry for regulatory screening of domoic acid in shellfish.

RationaleDomoic acid (DA) is a potent neurotoxin that accumulates in shellfish. Routine testing involves homogenization, extraction and chromatographic analysis, with a run time of up to 30 min. Improving throughput using ambient ionization for direct analysis of DA in tissue would result in significant time savings for regulatory testing labs.MethodsWe assess the suitability of laser ablation electrospray ionization high‐resolution mass spectrometry (LAESI‐HRMS) for high‐throughput screening or quantitation of DA in a variety of shellfish matrices. The method was first optimized for use with HRMS detection. Challenges such as tissue sub‐sampling, isobaric interferences and method calibration were considered and practical solutions developed. Samples included 189 real shellfish samples previously analyzed by regulatory labs as well as mussel matrix certified reference materials.ResultsDomoic acid was selectively analyzed directly from shellfish tissue homogenates with a run time of 12 s. The limits of detection were between 0.24 and 1.6 mg DA kg−1 tissue, similar to those of LC/UV methods. The precision was between 27 and 44% relative standard deviation (RSD), making the technique more suited to screening than direct quantitation. LAESI‐MS showed good agreement with LC/UV and LC/MS and was capable of identifying samples above and below 5 mg DA kg−1 wet shellfish tissue, one quarter of the regulatory limit.ConclusionsThese findings demonstrate the suitability of LAESI‐MS for routine, high‐throughput screening of DA. This approach could result in significant time savings for regulatory labs carrying out shellfish safety testing on thousands of samples annually. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

Biological effects of gold mine tailings on the intertidal marine environment in Nova Scotia, Canada

From 1861 to the 1940s, gold was produced from 64 mining districts in Nova Scotia, where mercury amalgamation was the dominant method for the extraction of gold from ore until the 1880s. As a result, wastes (tailings) from the milling process were contaminated by mercury and were high in naturally occurring arsenic. In 2004 and 2005, sediments, water and mollusc tissues were collected from 29 sampling stations at nine former gold mining areas along the Atlantic coastline and were analysed for arsenic and mercury. The resulting data were compared with environmental quality guidelines. Samples indicated high potential risk of adverse effects in the intertidal environments of Seal Harbour, Wine Harbour and Harrigan Cove. Arsenic in Seal Harbour was bioavailable, resulting in high concentrations of arsenic in soft-shell clam tissues. Mercury concentrations in tissues were below guidelines. This paper presents results of the sampling programs and implications of these findings.

The distribution, contamination and risk assessment of heavy metals in sediment and shellfish from the Red Sea coast, Egypt

Zn, Cu, Ni, V, Al, Pb, Cd, Hg, lipid and water contents were determined in the soft tissues of different shellfish species collected along the Red Sea shoreline. Metal contents showed a descending order of Zn > Cu > Ni > Al > V > Pb > Cd > Hg. The leachable concentrations found in the sediments gathered from the studied locations gave another descending order: Al > Zn > Ni > Pb > V > Cu > Cd. The determined leachable heavy metal contents in the sediment did not exceed the NOAA and CCME (Anonymous 1999) sediment quality guidelines. Accordingly, the sediments along the Egyptian Red Sea area did not pose any adverse impacts on the biological life. According to the hazard quotient (HQ) calculations for heavy metal contents in the soft tissue of shellfish, mercury did not pose any risk on human health; whereas, the other determined heavy metals gave HQ values of 1 < HQ < 10 and showed a possibility of risk on the long term. Cu is above the desirable levels in mussels. The RQ calculations of toddlers and adults reflected that Cu was the only heavy metal that had an adverse effect on toddlers’ health. Based on the human organizations (EPA, BOE, MAFF, and NHMRC) that proposed safety concentrations of heavy metals, the studied shellfish were somewhat safe for human consumption.

Use of Mytilus edulis biosentinels to investigate spatial patterns of norovirus and faecal indicator organism contamination around coastal sewage discharges

Bivalve shellfish have the capacity to accumulate norovirus (NoV) from waters contaminated with human sewage. Consequently, shellfish represent a major vector for NoV entry into the human food chain, leading to gastrointestinal illness. Identification of areas suitable for the safe cultivation of shellfish requires an understanding of NoV behaviour upon discharge of municipal-derived sewage into coastal waters. This study exploited the potential of edible mussels (Mytilus edulis) to accumulate NoV and employed the ISO method for quantification of NoV within mussel digestive tissues. To evaluate the spatial spread of NoV from an offshore sewage discharge pipe, mesh cages of mussels were suspended from moorings deployed in a 9 km2 grid array around the outfall. Caged mussels were retrieved after 30 days and NoV (GI and GII), total coliforms and E. coli enumerated. The experimentally-derived levels of NoV GI and GII in mussels were similar with total NoV levels ranging from 7 × 101 to 1.6 × 104 genome copies g−1 shellfish digestive gland (ΣGI + GII). NoV spread from the outfall showed a distinct plume which matched very closely to predictions from the tidally-driven effluent dispersal model MIKE21. A contrasting spatial pattern was observed for coliforms (range 1.7 × 102 to 2.1 × 104 CFU 100 g−1 shellfish tissue) and E. coli (range 0–1.2 × 103 CFU 100 g−1 shellfish tissue). These data demonstrate that hydrodynamic models may help inform effective exclusion zones for bivalve harvesting, whilst coliform/E. coli concentrations do not accurately reflect viral dispersal in marine waters and contamination of shellfish by sewage-derived viral pathogens.

Development of Certified Reference Materials for Diarrhetic Shellfish Poisoning Toxins, Part 2: Shellfish Matrix Materials.

Okadaic acid (OA) and its analogs, dinophysistoxins-1 (DTX1) and -2 (DTX2) are lipophilic biotoxins produced by marine algae that can accumulate in shellfish and cause the human illness known as diarrhetic shellfish poisoning (DSP). Regulatory testing of shellfish is required to protect consumers and the seafood industry. Certified reference materials (CRMs) are essential for the development, validation, and quality control of analytical methods, and thus play an important role in toxin monitoring. This paper summarizes work on research and development of shellfish tissue reference materials for OA and DTXs. Preliminary work established the appropriate conditions for production of shellfish tissue CRMs for OA and DTXs. Source materials, including naturally incurred shellfish tissue and cultured algae, were screened for their DSP toxins. This preliminary work informed planning and production of a wet mussel (Mytilus edulis) tissue homogenate matrix CRM. The homogeneity and stability of the CRM were evaluated and found to be fit-for-purpose. Extraction and LC-tandem MS methods were developed to accurately certify the concentrations of OA, DTX1, and DTX2 using a combination of standard addition and matrix-matched calibration to compensate for matrix effects in electrospray ionization. The concentration of domoic acid was also certified. Uncertainties were assigned following standards and guidelines from the International Organization for Standardization. The presence of other toxins in the CRM was also assessed and information values are reported for OA and DTX acyl esters.

Permanent culture and parasitic impact of the microalga Coccomyxa parasitica, isolated from horse mussel Modiolus kurilensis

Animals with deformed shells and microalgal invasion have been identified in the natural population of the horse mussel species Modiolus kurilensis of Peter the Great Bay in the Sea of Japan. The haemolymph is initially infested with algae, followed by the rectum, siphons, mantles and gonads located in the posterior body areas. Mantles, which are primarily exposed to light, are major depots for algae. The microscopic analysis of algal cells has revealed the absence of flagella and pyrenoids, the presence of single chloroplast, and reproduction by autosporulation, with dispores prevailing over tetraspores. These results, together with the nearly complete sequence analysis of small subunit (SSU) 18S rDNA (1728bp), have confirmed that these cells are Coccomyxa parasitica. A newly developed method of isolating microalgae from mollusk tissues has facilitated the continuous pure - probably axenic - culture of C. parasitica, thereby providing a description of the time course of each life stage. Histological analyses have revealed significant haemocyte infiltration into the mantles, gonads, kidneys and digestive gland tissues infested with microalgae and the gill tissues, in which the intruder was not identified. Algal encapsulation with major focal areas of fibrosis and amorphic necrosis has been revealed in these infested organs. The spaces between the gonad follicles and digestive gland tubules were significantly widened as these areas were filled with a mass of algae and phagocytic haemocytes, showing acini with a thickened basement membrane. The mantles and kidneys of Modiolus displayed significant morphological deviations of different cells in epithelial, connective and muscle tissues, resulting in the dysfunction of the infested organs. Therefore, C. parasitica, which reproduces in the culture, regardless of the host, is a facultative parasite, causing major pathological alterations, such as anomalous histomorphological patterns and infested organ dysfunctions.

Trace Metals in Noah's Ark Shells (Arca noae Linnaeus, 1758): Impact of Tourist Season and Human Health Risk.

Commercially important bivalve Noah's Ark shell (Arca noae Linnaeus, 1758) represents a high-quality seafood product, but the data on levels of metal contaminants that could pose a human health risk and also on some essential elements that are important for health protection are lacking. This study examined the concentrations of Cd, Pb, Cr, Ni, Cu, Co, and Zn in the soft tissue of A. noae from harvesting area in the central Adriatic Sea, to survey whether heavy metals are within the acceptable limits for public health and whether tourism could have an impact on them. The concentrations of analysed metals varied for Cd: 0.15-0.74, Pb: 0.06-0.26, Cr: 0.11-0.34, Ni: 0.09-0.22, Cu: 0.65-1.95, Co: 0.04-0.09, and Zn: 18.3-74.7mg/kg wet weight. These levels were lower than the permissible limits for safe consummation of seafood, and only for Cd, some precautions should be taken into account if older shellfish were consumed. Increase of Cd, Cr, and Cu in shell tissue was observed during the tourist season at the site closest to the marine traffic routes, indicating that metal levels in shellfish tissue should be monitored especially carefully during the peak tourist season to prevent eventual toxic effects due to increased intake of metals, specifically of Cd.

An Outbreak of Norovirus Infection from Shellfish Soup Due to Unforeseen Insufficient Heating During Preparation.

Norovirus causes large outbreaks involving all age groups and are considered the most common cause of infectious foodborne diseases worldwide. The aim of this study was to describe a norovirus outbreak connected to insufficient heat treatment during preparation of a shellfish soup in serving portions, during a company Christmas celebration in Norway, December 2013. A questionnaire sent to the employees, showed that 67% (n=43) of the celebration participants, reported gastrointestinal symptoms including stomach pain, vomiting, diarrhoea and light fever in the period between 24 and 48h post celebration. Several dishes were served, including shellfish soup made with carpet shell clams (Tapes rhomboides) in porcelain cups. Consuming this soup, was the only significant risk factor for infection. Norovirus GI and GII were detected in the remaining raw shellfish. To mimic the time and temperature obtained during bivalve soup preparation, raw chopped shellfish tissue and raw cepa onion were added in porcelain cups tempered to 20°C. To each of these cups, boiling soup base was added. The temperature in the shellfish tissue was continuously recorded, and showed a maximum of 49°C in the period between 3 and 7min after adding the boiling soup base. After 1h the temperature was 30°C. This time and temperature combination was obviously not sufficient for inactivation of norovirus present in the shellfish tissue. In conclusion, the heat-absorbing capacity of cold ingredients, utensils and table wear porcelain should not be underestimated during food production. Consumers who want to avoid eating raw shellfish, should not assume that the shellfish tissue in preparation as described in our study is adequately heat treated.

Surface plasmon resonance biosensing: Approaches for screening and characterising antibodies for food diagnostics

Research in biosensing approaches as alternative techniques for food diagnostics for the detection of chemical contaminants and foodborne pathogens has increased over the last twenty years. The key component of such tests is the biorecognition element whereby polyclonal or monoclonal antibodies still dominate the market. Traditionally the screening of sera or cell culture media for the selection of polyclonal or monoclonal candidate antibodies respectively has been performed by enzyme immunoassays. For niche toxin compounds, enzyme immunoassays can be expensive and/or prohibitive methodologies for antibody production due to limitations in toxin supply for conjugate production. Automated, self-regenerating, chip-based biosensors proven in food diagnostics may be utilised as rapid screening tools for antibody candidate selection. This work describes the use of both single channel and multi-channel surface plasmon resonance (SPR) biosensors for the selection and characterisation of antibodies, and their evaluation in shellfish tissue as standard techniques for the detection of domoic acid, as a model toxin compound. The key advantages in the use of these biosensor techniques for screening hybridomas in monoclonal antibody production were the real time observation of molecular interaction and rapid turnaround time in analysis compared to enzyme immunoassays. The multichannel prototype instrument was superior with 96 analyses completed in 2h compared to 12h for the single channel and over 24h for the ELISA immunoassay. Antibodies of high sensitivity, IC50's ranging from 4.8 to 6.9ng/mL for monoclonal and 2.3–6.0ng/mL for polyclonal, for the detection of domoic acid in a 1min analysis time were selected. Although there is a progression for biosensor technology towards low cost, multiplexed portable diagnostics for the food industry, there remains a place for laboratory-based SPR instrumentation for antibody development for food diagnostics as shown herein.

Specific metabolic features in tissues of the ark clam Anadara kagoshimensis Tokunaga, 1906 (Bivalvia: Arcidae), a Black Sea invader

Parameters of the antioxidant system as well as carbohydrate, protein, and energy metabolisms in the tissues of an invader species, the bivalve mollusk Anadara kagoshimensis, are compared. Tissue specificity of the examined parameters is demonstrated. Along with the hepatopancreas and gills, the foot of anadara is shown to be an important metabolic organ with a high metabolism and an antioxidant defense. The content of low molecular weight biological antioxidants and antioxidant enzyme activities are specifically balanced in the examined mollusk tissues. The behavioral, physiological, and biochemical features that have provided successful invasion of this mollusk in the Black Sea–Azov basin are discussed.

Polychlorinated biphenyls, organochlorine pesticides and trace metals in cultured and harvested bivalves from the eastern Adriatic coast (Croatia)

Polychlorinated biphenyls, organochlorine pesticides and trace metals were determined in tissues of bivalve molluscs (Mytilus galloprovincialis, Ostrea edulis, Venus verrucosa, Arca noae and Callista chione), collected from 11 harvesting and 2 cultured locations along the eastern Adriatic coast, in May and November 2012. Concentrations (ng g−1 dry weight) of organochlorines ranged from 1.53 to 21.1 for PCBs and 0.68 to 5.21 for p,p'-DDTs. HCB, lindane, heptachlor and aldrin-like compounds were found in lower levels or were not detected. Metal concentrations (mg kg−1 dry weight) ranged from 0.23 to 4.03 for Cd, 0.87–3.43 for Cr, 3.69–202.3 for Cu, 0.06–0.26 for HgT, 0.62–9.42 for Ni, 0.95–4.64 for Pb, and 55.76–4010.3 for Zn. Established organochlorine and trace metal levels were lower than the maximum allowable levels in seafood set by the European Commission.

Особенности активности ферментов энергетического обмена в тканях черноморских моллюсков разной подвижности в норме и при патологии

Одним из важнейших показателей метаболизма у моллюсков является активность ферментов энергетического обмена ― лактатдегидрогеназы (ЛДГ, 1.1.1.27) и малатдегидрогеназы (МДГ, 1.1.1.37), неизменно участвующих в адаптационных перестройках. Целью работы было сравнение активности ферментов энергетического обмена в тканях черноморских моллюсков с различными эколого-физиологическими особенностями. Объектами исследования служили половозрелые моллюски Mytilus galloprovincialis, Flexopecten glaber ponticus, Аnadara kagoshimensis и Rapana venosa в нерестовый период. Длина раковины мидии составляла 50–55 мм, анадары ― 25–33 мм, рапаны ― 50–80 мм, флексопектена ― 35–54 мм. Активность ферментов измеряли спектрофотометрически (при 340 нм and 25 ºC) по скорости окисления НАД-Н в цитоплазме тканей. Максимальная активность ЛДГ и МДГ у мидии, анадары и рапаны установлена в мышечной ткани, минимальная ― в гепатопанкреасе. Уровень активности МДГ в ноге, аддукторе, жабрах и гепатопанкреасе двустворчатых моллюсков-фильтраторов мидии и анадары достоверно выше, чем ЛДГ. Наибольшей активностью МДГ характеризовались ткани устойчивой к гипоксии анадары. Активность ЛДГ и МДГ в однотипных тканях хищного моллюска рапаны существенно не различалась. Показано, что активность ЛДГ в гепатопанкреасе, жабрах и мышечной ткани пропорциональна подвижности вида и увеличивается в ряду мидия ― анадара ― рапана. У Flexopecten glaber ponticus, собранного в зоне сброса воды с рисовых чеков и пораженного перфораторами, тканевая специфика активности ЛДГ и МДГ была нарушена, уровень активности ферментов понижен и не соответствовал естественной подвижности вида. Обсуждено состояние здоровья черноморского гребешка, находящегося под угрозой исчезновения в дикой природе.

Distribution, occurrence and biotoxin composition of the main shellfish toxin producing microalgae within European waters: A comparison of methods of analysis

Harmful algal blooms (HABs) are a natural global phenomena emerging in severity and extent. Incidents have many economic, ecological and human health impacts. Monitoring and providing early warning of toxic HABs are critical for protecting public health. Current monitoring programmes include measuring the number of toxic phytoplankton cells in the water and biotoxin levels in shellfish tissue. As these efforts are demanding and labour intensive, methods which improve the efficiency are essential. This study compares the utilisation of a multitoxin surface plasmon resonance (multitoxin SPR) biosensor with enzyme-linked immunosorbent assay (ELISA) and analytical methods such as high performance liquid chromatography with fluorescence detection (HPLC-FLD) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for toxic HAB monitoring efforts in Europe. Seawater samples (n=256) from European waters, collected 2009–2011, were analysed for biotoxins: saxitoxin and analogues, okadaic acid and dinophysistoxins 1/2 (DTX1/DTX2) and domoic acid responsible for paralytic shellfish poisoning (PSP), diarrheic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP), respectively. Biotoxins were detected mainly in samples from Spain and Ireland. France and Norway appeared to have the lowest number of toxic samples. Both the multitoxin SPR biosensor and the RNA microarray were more sensitive at detecting toxic HABs than standard light microscopy phytoplankton monitoring. Correlations between each of the detection methods were performed with the overall agreement, based on statistical 2×2 comparison tables, between each testing platform ranging between 32% and 74% for all three toxin families illustrating that one individual testing method may not be an ideal solution. An efficient early warning monitoring system for the detection of toxic HABs could therefore be achieved by combining both the multitoxin SPR biosensor and RNA microarray.

High level of tetracosapolyenoic fatty acids in the cold-water mollusk Tochuina tetraquetra is a result of the nudibranch feeding on soft corals

Fatty acid (FA) markers are used to trace predator–prey relationships in the marine environment. Soft corals contain tetracosapolyenoic acids (TPA), namely 24:5n-6 and 24:6n-3, which are considered as octocoral FA markers. The nudibranch mollusks are known to feed on soft corals. To check whether TPA are transferred from soft corals to nudibranch mollusks during their nutrition, we determined and compared FA compositions of total lipids of Tochuina tetraquetra and soft corals (Acanella sp., Anthomastus rylovi, Gersemia fruticosa, and Paragorgia arborea) collected together near the Kuril Islands (the depths of 80–550 m). FA compositions of T. tetraquetra, Acanella sp. and A. rylovi were described for the first time. In Acanella sp., G. fruticosa, A. rylovi, and P. arborea, the average contents of TPA were 6.5, 13.4, 5.9, and 12.0 % of total FAs, whereas the 24:5n-6/24:6n-3 ratio was 1.0, 1.4, 5.4, and 2.6, respectively. The high level of TPA (21.7 %) found in T. tetraquetra indicates that 24:5n-6 and 24:6n-3 are transferred from soft corals to the mollusks during their feeding and accumulated in mollusk tissues. The most possible feed source of the mollusk is suggested to be G. fruticosa and/or Acanella sp., because the 24:5n-6/24:6n-3 ratios in T. tetraquetra and these soft corals were similar. Thus, the TPA could be used as FA markers to estimate a proportion of soft corals in feeding of cold-water nudibranch mollusks.