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PubMed1990

Presence of saxitoxin in toxic extracts from Gonyaulax polyedra.

A "red tide" bloom of Gonyaulax polyedra occurred in Italy in Autumn, 1988. Algal concentrated extracts and undiluted water samples from the bloom were tested both with the Microtox system and a mouse bioassay, revealing the presence of paralytic shellfish poison-like neurotoxins. Saxitoxin levels evaluated on the basis of toxicological and instrumental analysis showed discrepancies. Other toxins could be present in addition to paralytic shellfish poison.

Animals↗

PubMed1993

Identification of protein phosphatase inhibitors of the microcystin class in the marine environment.

Toxins produced by marine phytoplankton represent a severe global health hazard to humans that eat seafood and are also responsible for massive natural fish kills in specialized bloom situations. Tumour-promoting hepatotoxins from the freshwater microcystin/nodularin class were identified in Northeastern Pacific Ocean, Eastern Canadian and European mussels for the first time. These hepatotoxins were detected at biologically active levels up to three-fold higher than accepted quarantine levels for the diarrhetic shellfish toxin okadaic acid (OA), based on their activity (in microcystin-LR equivalent units) in a liquid chromatography (LC)-linked protein phosphatase bioassay. The presence of microcystins/nodularins in oceanic shellfish identifies a potentially novel class of intoxication which is also prevalent in other forms of marine aquatic life, namely sponges and fish. The widespread presence of prokaryotic microcystins and nodularins in the marine environment may be indicative of the importance of signal transduction pathways involving potent inhibition of protein phosphatases in early marine eukaryotes.

Amino Acid Sequence↗

PubMed1996

Occurrence of paralytic toxin in Taiwanese crab Atergatopsis germaini.

Paralytic toxicity was detected by paralytic shellfish poison bioassay for all 17 specimens of the xanthid crab A. germaini collected from northern Taiwan in November 1993. The average toxicity of crab specimens was 3809 +/- 2591 mouse units (mean +/- S.D.). The toxin was partially purified from ethanolic extract of the crab by ultrafiltration and Bio-Gel P-2 column chromatography. Electrophoresis, TLC, HPLC, ultraviolet spectrum and GC-MS analyses indicated that the crab toxin was composed of gonyautoxin 3 (50%), neosaxitoxin and saxitoxin (7%), a novel paralytic shellfish poison-like toxin (40%) and tetrodotoxin (3%).

Animals↗

PubMed1989

Cross-reactivity of IgE antibodies to caddis fly with arthropoda and mollusca.

We investigated the possibility that subjects with IgE antibodies to an inhalant insect allergen, such as caddis fly, might also have antibodies to cross-reacting carbohydrate determinants (CCDs). IgE antibodies to cross-reacting allergens in caddis flies, mussels, oysters, shrimps, crabs, honeybee, and yellow jacket venoms were determined by RAST, RAST inhibition, and immunoblot studies with sera from three different sources: (1) sera of patients with well-defined inhalant atopy to caddis fly, (2) sera with IgE anti-CCD antibodies from subjects without known exposure to caddis fly, and (3) hyperimmune antisera with IgG anti-CCD antibodies raised as a result of immunization of rabbits with grass-pollen extract, buckwheat glycoprotein, or with honeybee venom. Sera from groups 2 and 3 reacted with Sepharose-coupled caddis fly extract in a RAST-type assay and elicited virtually identical patterns on immunoblots of caddis fly extract separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas the sera from group 1 atopic patients did not react with CCD-rich material. However, indications for other types of cross-reacting antibodies were detected. The IgE antibodies of one of the patients studied (who was allergic not only to caddis fly but also to shellfish) were found to detect a cross-reacting homologous protein in extracts of mussel, oyster, shrimp, crab, honeybee, and yellow jacket venom. Preliminary results suggest that this cross-reacting 13 kd protein, the most prominent caddis fly allergen, is an invertebrate hemoglobin (erythrocruorin)-like molecule. These studies suggest the possibility that patients sensitized by exposure to caddis fly antigens could develop allergic reactions during their first exposure to shellfish or to their first bee sting.

Adult↗

PubMed1996

Organochlorine contaminants in the estuarine and coastal marine environments of the Fiji Islands.

No information has been published on the presence of organochlorine pesticides and polychlorinated biphenyls in the Fiji Islands. This paper reports the first data on the concentration of a range of organochlorine compounds in sediments and shellfish in the estuarine and coastal marine environment around Fiji. Twenty-three sediment and two shellfish samples were analysed for 22 pesticides and related residues, and PCBs. While a significant number of organochlorines (20 pesticide related species and PCBs) was detected, the concentrations were generally very low (< 10 ng g), indicative of a relatively 'less contaminated' marine environment. Relatively high concentrations were observed only near the two major ports (Suva and Lautoka), with Suva harbour samples having the largest number of detectable species and the largest total concentrations of organochlorines (up to 91 ng g). No PCBs were detected in areas away from major industrial centres. The variations in the concentrations found, and the possible sources and movement of the organochlorine contaminants are discussed.

Journal Article↗

PubMed1990

Arsenic intake and excretion by Japanese adults: a 7-day duplicate diet study.

The amount of arsenic in the urine, faeces and in duplicate diets of two couples who had eaten customary Japanese meals were monitored for 7 days by arsine-generator atomic absorption spectrophotometry. For the four volunteers, the mean daily intake of arsenic from their diets was 182 micrograms (range 27 to 376 micrograms). The dietary arsenic was composed of 5.7% inorganic arsenic, 3.6% methylarsonic acid, 27.4% dimethylarsinic acid and 47.9% trimethylarsenic compounds. The mean amounts of arsenic eliminated daily in urine and faeces were 148 micrograms (50-416 micrograms) and 46 micrograms (0-138 micrograms), respectively. The urinary arsenic was composed of 1.4% inorganic arsenic, 3.5% methylarsonic acid, 33.6% dimethylarsinic acid and 61.4% trimethylarsenic compounds. The daily intake of arsenic influenced the total amount of arsenic excreted in the urine (r = 0.7302, P less than 0.01) and the amount eliminated in the faeces (r = 0.5900, P less than 0.01) the next day. Specifically, there was also a significant correlation between the daily intakes of trimethylarsenic compounds and dimethylarsinic acid and the amounts of these compounds found in the urine the following day (r = 0.6833, P less than 0.01 and r = 0.6630, P less than 0.01, respectively). Considering the amounts of arsenic compounds present in seafood and in other components of the diet together with the urinary elimination patterns of arsenic compounds, it seemed probable that the trimethylarsenic compounds in the urine originated largely from fish and shellfish, which contain mainly arsenobetaine. Trimethylarsenic compounds in the urine should therefore be the preferred indicator of arsenic arising from the ingestion of seafood, especially fish and shellfish. In this study, the mean daily intake of inorganic arsenic from the diet (0.18 micrograms/kg) did not exceed the FAO/WHO JECFA Tolerable Daily Intake of 2 micrograms inorganic arsenic kg.

Adult↗

PubMed1995

Microflora and tetrodotoxin-producing bacteria in a gastropod, Niotha clathrata.

Shellfish (Niotha clathrata) were collected in both July and November from three locations in Taiwan (Pingtung, Kaohsiung and Chiai Prefecture) and assayed for anatomical distribution of tetrodotoxin (TTX) and aerobic heterotrophic bacteria. Pingtung specimens showed higher toxicity than those from Kaohsiung and Chiai, and did not show much seasonal variation. At each site, the total aerobic bacterial counts in November samples were higher than in July. The predominant genera were Vibrio, Pseudomonas, Pasteurella, Aeromonas and Plesiomonas. Vibrio comprised more than 35% of the genera, with V. alginolyticus as the major species. The viable counts of Vibrio species were higher in November than in July. However, the results did not suggest any relationship between the total count or viable count and the toxicity of the shellfish. HPLC, UV and gas chromatographic-mass spectrometric analyses demonstrated that some of the bacteria isolated, such as V. alginolyticus, V. parahaemolyticus, Pseudomonas spp. Plesiomonas sp. and Aeromonas sp., produced TTX and/or related substances.

Animals↗

PubMed1990

Domoic acid, an environmental toxin, produces hippocampal damage and severe memory impairment.

Microinjections of domoic acid, a presumed shellfish toxin, into the hippocampal formation of rats produces degeneration of CA3 and CA1 pyramidal cells and dentate gyrus granule cells. We demonstrate that domoate-treated rats exhibit a long-lasting anterograde amnesia for spatial information in the Morris water task. This preparation provides a good model for examining neurotoxicity and the anterograde amnesic syndrome observed in humans following consumption of domoate-contaminated shellfish.

Amnesia↗

PubMed1987

Activities of adenylate-degrading enzymes in muscles from vertebrates and invertebrates.

Activities of adenylate-degrading enzymes in muscles of vertebrates and invertebrates were determined. Mammalian and fish muscles showed a markedly higher activity of AMP deaminase with a lower level of adenosine deaminase and 5'-nucleotidase. Cephalopods showed an active adenosine deaminase and a 5'-nucleotidase which preferred AMP as the substrate. Negligible deamination of AMP and adenosine and little phosphohydrolase activity toward AMP and IMP were observed in the shellfish muscles. Adenine nucleotides can be degraded to form IMP via the AMP deaminase reaction in vertebrate muscles, while dephosphorylation of AMP to adenosine, which is then converted to inosine, appears to proceed in cephalopods. Adenylates can be hardly degraded in shellfish muscles.

5'-Nucleotidase↗

PubMed1987

Clinical and ecological characteristics of Vibrio vulnificus in the northeastern United States.

Multiple seawater sites in the northeastern United States, particularly Long Island Sound, and shellfish from Long Island Sound were sampled from April to November for 3 successive yr, 1983-1985. Hospitals in coastal and metropolitan areas of Connecticut were surveyed for the same 3-yr period, Vibrio vulnificus can be found in these waters during the summer months. The appearance of these virulent bacteria in both seawater and shellfish are a function of the water temperature; no V. vulnificus could be isolated until the temperature was approximately 17 degrees C. Although the risk of infection is small, as shown by isolation of this organism from patients, certain high-risk groups exist. Consumption of raw shell fish during the summer months should be discouraged in people with liver disease or patients on immunosuppressive therapy.

Animals↗

PubMed2005

Estimation of 1999-2004 dietary daily intake of PCDDs, PCDFs and dioxin-like PCBs by a total diet study in metropolitan Tokyo, Japan.

A study of the dietary intake of dioxins, consisting of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) through foods retailed in the metropolitan Tokyo area from 1999 to 2004 was carried out by the total diet-market basket method on the basis of food classification (14 groups) and the data on food consumption in the Tokyo region obtained from the Japan Nutrition Survey. The daily intake of dioxins per kg of body weight for a 50 kg average adult body was 2.18 pg TEQ/kg/day in 1999, 1.87 pg TEQ/kg/day in 2000, 1.25 pg TEQ/kg/day in 2001, 1.60 pg TEQ/kg/day in 2002 and 2003 and 1.55 pg TEQ/kg/day in 2004, respectively. These amounts were less than the tolerable daily intake (TDI) of 4 pg TEQ/kg/day for dioxins established in Japan. The dioxins taken daily through fish and shellfish (group 10) accounted for more than 50% of sum WHO-TEQs. In addition, more than 90% of the daily intake of dioxins was taken through fish and shellfish (group 10), meat and eggs (group 11), milk and dairy products (group 12). Also, this study clearly showed that the ratio of dioxin-like PCBs in the daily intake of dioxins was increasing yearly because the reduction rate of dioxin-like PCBs was lower than that of PCDDs and PCDFs in foods.

Benzofurans↗

PubMed2006

Organochlorine compounds (PCBs, PCDDs and PCDFs) in seafish and seafood from the Spanish Atlantic Southwest Coast.

Concentrations and congener specific profiles of PCDD/Fs and PCBs were determined in edible fish and seafood species from the Coast of Huelva, in the Spanish southwest Atlantic coast. Five fish species, namely wegde sole (Dicologoglossa cuneata), common sole (Solea vulgaris), white seabream (Diplodus sargus), sardine (Sardina pilchardus), angler fish (Lophius piscatorius), two shellfish species (Donax trunculus and Chamelea gallina), common cuttlefish (Sepia officinalis) and prawns (Parapenaeus longirostris), frequently found and consumed in the area were analysed. Concentrations ranged from 861 to 23787pg/g wet weight for total PCBs, while 2,3,7,8-PCDD/Fs showed concentrations ranging from 0.2 to 1.18pg/g wet weight. WHO-TEQ concentrations ranged from 0.038 to 0.186pg WHO-TEQ(PCDD/Fs)/g wet weight, values well below the maximum concentrations established by the EU. When non- and mono-ortho PCBs were included the values increased to a maximum of 0.99pg WHO-TEQ(PCDD/Fs+PCBs)/g wet weight. The PCB and PCDD/F accumulation pattern found in the samples analysed showed a distribution typically reported for marine samples, and no remarkable differences were found between species. The PCBs were the ones contributing with the highest percentage to the total TEQ content in most species studied. Concerning the seafood, specially prawns and shellfish, the opposite was observed and PCDD/Fs were found to contribute with a higher percentage than PCBs. The congener specific contribution to the TEQ showed PCB 126 followed by 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF as the most abundant ones.

Animals↗

PubMed2006

The inhibition of CHO-K1-BH4 cell proliferation and induction of chromosomal aberrations by brevetoxins in vitro.

Brevetoxins (PbTxs) are highly potent trans-syn polyether neurotoxins produced during blooms of several species of marine dinoflagellates, most notably Karenia brevis. These neurotoxins act on voltage-sensitive sodium channels prolonging the active state. During red tides, the commercial fishing and tourism industries experience millions of dollars of lost revenue. Human consumption of shellfish contaminated with PbTxs results in neurotoxic shellfish poisoning (NSP). Additionally, blooms of K. brevis are potentially responsible for adverse human health effects such as respiratory irritation and airway constriction in coastal residents. There is little information regarding the full range of potential toxic effects caused by PbTxs. Recent evidence suggests that PbTxs are genotoxic substances. The purpose of this study was to determine if PbTxs could induce chromosomal aberrations and inhibit cellular proliferation in CHO-K1-BH4 cells, and if so, could the damage be negated or reduced by the PbTx antagonist brevenal. Results from the chromosomal aberrations assay demonstrated that PbTxs are potent inducers of CHO-K1-BH4 chromosome damage. Results from the inhibition of cellular proliferation assays demonstrated that PbTxs inhibit the ability of CHO-K1-BH4 cells to proliferate, an effect which can be reduced with brevenal.

Animals↗

PubMed2006

Optimisation of production of a domoic acid-binding scFv antibody fragment in Escherichia coli using molecular chaperones and functional immobilisation on a mesoporous silicate support.

Domoic acid is a potent neurotoxin that can lead to amnesic shellfish poisoning in humans through ingestion of contaminated shellfish. We have produced and purified an anti-domoic acid single-chain Fragment variable (scFv) antibody fragment from the Escherichia coli periplasm. Yields of functional protein were increased by up to 100-fold upon co-production of E. coli DnaKJE molecular chaperones but co-overproduction of GroESL led to a reduction in solubility of the scFv. Co-production of the peptidyl-prolyl isomerase trigger factor resulted in accumulation of unprocessed scFv in the E. coli cytoplasm. This was due to an apparent bottleneck in translocation of the cytoplasmic membrane by the recombinant polypeptide. Co-expression of the E. coli disulfide bond isomerase dsbC increased scFv yields by delaying lysis of the host bacterial cells though this effect was not synergistic with molecular chaperone co-production. Meanwhile, use of a cold-shock promoter for protein production led to accumulation of greater amounts of scFv polypeptide which was predominantly in insoluble form and could not be rescued by chaperones. Purification of the scFv was achieved using an optimised metal affinity chromatography procedure and the purified protein bound domoic acid when immobilised on a mesoporous silicate support. The work outlines the potential benefit of applying a molecular chaperone/folding catalyst screening approach to improve antibody fragment production for applications such as sensor development.

Cloning, Molecular↗

PubMed2004

Consideration of cultural and lifestyle factors in defining susceptible populations for environmental disease.

To define mechanisms of susceptibility for populations affected by environmental exposures, both exposure and toxicity assessments must be considered. This review examines cultural and lifestyle factors that help define potentially susceptible populations in two groups, Asian and Pacific Islanders (API) and members of Tribal Nations in the Pacific Northwest region of the US and Western Canada. These groups, which may consume 10 times more fish and seafood than average US consumers, have special dietary practices that can lead to significant exposures to persistent pollutants and biotoxins found in fish and shellfish. The mechanism of toxicity of these contaminants is also important. Using the example of dioxin-like polychlorinated biphenyls (PCBs), different risk assessment approaches are presented and the analytical sensitivity needed to assess risk for different consumption groups is evaluated quantitatively. Our studies have also shown that regulatory agencies evaluation of fish consumption for average US populations do not always adequately consider unique consumption and cooking practices of these groups. Partnering with communities is important for appropriate exposure and risk assessments. This also empowers proactive action by communities to evaluate the risks and many benefits of fish and shellfish consumption and develop risk management strategies tailored for their communities.

Animals↗

PubMed2004

High affinity for the rat brain sodium channel of newly discovered hydroxybenzoate saxitoxin analogues from the dinoflagellate Gymnodinium catenatum.

The paralytic shellfish poison family has been recently extended by the discovery of several analogues possessing a hydoxybenzoate moiety instead of the carbamoyl group one finds in saxitoxin, the parent molecule of this toxin family. We have investigated the potency of these new analogues on a representative isoform of the pharmacological target of these toxins, the voltage gated sodium channel. These toxins were found to have K1's in the low nanomolar range, only slightly less potent than saxitoxin. The hydroxybenzoate group may increase the lipophilicity of these toxins and improve their ability to pass through epithelia and therefore its uptake and elimination in both intoxication victims and animals that bioaccumulate paralytic shellfish toxins.

Animals↗

PubMed2005

Morphology, toxin composition and pigment content of Prorocentrum lima strains isolated from a coastal lagoon in southern UK.

Prorocentrum lima was isolated from the coastal Fleet lagoon, Dorset, UK in 2000 and a number of clonal cultures established. These were analyzed for okadaic acid (OA), dinophysistoxin-1 (DTX-1), DTX-2, DTX-4 and diol esters by liquid chromatography coupled to mass spectrometry. OA concentrations varied from 0.4 to 17.1pg OAcell(-1) and DTX-1 from 0.4 to 11.3pg DTX-1cell(-1); DTX-2 was not detected in these isolates. OA and DTX-1 were detected in the culture media, as a result of toxin excretion. DTX-4 and a selection of DTX-4 diol esters were identified using selected ion monitoring, although not all strains produced these compounds. Cell size and number of marginal and valve pores of each strain were observed using scanning electron microscopy. OA and DTX-1 concentrations, pigment content and changes in nitrate and phosphate concentrations in the culture media were followed during growth of one strain of P. lima in batch culture. Diarrhetic shellfish poisoning (DSP) toxins have been previously detected in shellfish cultivated in the Fleet lagoon, but in the absence of any Dinophysis sp. cells. The identification of toxic P. lima strains from the Fleet suggests that this dinoflagellate is the most probable source of occasional DSP detected in the lagoon.

Animals↗

PubMed2005

Lipophilic toxicity from the marine dinoflagellate Karenia brevisulcata: use of the brevetoxin neuroblastoma assay to assess toxin presence and concentration.

A method for assessing the presence and concentration of a major toxin produced by Karenia brevisulcata has been developed, based on the neuroblastoma assay for brevetoxins. This cytotoxicity assay, coupled with observations of the dose-response relationship and of changes in cellular morphology during the assay gave a characteristic toxin 'signature'. This signature was consistent whether the toxicity was assessed in extracts of shellfish, seawater samples, uni-algal cultures of K. brevisulcata, or in partially purified toxin samples. Using this method it was possible to confirm the presence of this toxicity during a mixed Karenia bloom, and infer that K. brevisulcata toxin (KBT) was the probable cause of the fish and shellfish mortality observed at that time. The neuroblastoma assay thus provides a solution to the problem of confirming the presence of KBT in suspected K. brevisulcata events, even in the absence of a known toxin structure.

Animals↗