Ozone detoxification of paralytic shellfish poison in the softshell clam (Mya arenaria).
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Mortality of shags and other sea birds caused by paralytic shellfish poison.
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Animals↗
Taxonomic difficulties in red tide and paralytic shellfish poison studies: the "tamarensis complex" of Gonyaulax.
The type illustrations of the dinoflagellate Gonyaulax tamarensis contain an apparent reversal of the epithecal plates. Furthermore a culture from the type locality has been found not to be toxigenic. These two features have led a recent author to doubt the appropriateness of the allocation of toxic populations in the North Atlantic to this species or a variety of it (var. excavata Braarud). The latter has been raised to the status of a distinct species but the wrong name has been applied to it (G. excavata) as, according to the rules of priority, it should be G. phoneus (Woloszynska & Conrad) nov. comb. A history of this confused situation is provided. The criteria by which other similar species are recognised are summarised. The necessity for further study on the specific distinction of these taxa is stressed. G. conjuncta has been so inadequately described or rejected. Variability in the plate pattern of a culture of G. tamarensis var. excavata from British Columbia is illustrated and its bearing on the taxonomy of the group discussed. The presence of this toxic variety on the west coast of N. America is a new record for the Pacific Ocean.
Animals↗
Eutrophication, marine biotoxins, human health.
Eutrophication phenomena in marine coastal waters can today be explained on the basis of natural or anthropogenic causes. Undesirable effects and also sanitary problems in both types of eutrophication are often produced, but they may differ greatly in frequency and significance. Some algal biotoxins can affect both marine animals and man, whilst others affect man alone. From data currently available it appears that the sanitary state of man can be affected through the digestive, respiratory and cutaneous apparatus. Four main dinoflagellate biointoxications are now recognized: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), diarrhoetic shellfish poisoning (DSP), and venerupin poisoning. Other biointoxications are due to a diatom bloom responsible for amnesic shellfish poisoning (ASP) and to blue algae blooms which have effects on the skin and the respiratory tract. All these marine toxins are considered and particular attention is paid to: producing organisms, chemistry of the components, compromised sea foods, methods of analysis, occurrence worldwide, human intoxications, toxicology and mechanism of action on a molecular level, therapeutical notes, tolerance levels and remarks on safety. Attention is also paid to the relationship between the anthropogenic eutrophication and PSP and DSP since these are the most widespread biointoxications from toxic marine dinoflagellates in the world today and for which the European Economic Community (EEC) is proposing health legislation such as tolerance limits and methods for official analysis. In view of the harmful potential of coastal anthropogenic eutrophication, the main current committment of various countries concerns control. Finally, it is important to develop a suitable monitor research system using all the specific standards of allowed toxic substances, and also research on effective antiodotes against all biotoxins.
Animals↗
Illness associated with seafood.
Seafood is a common vehicle for the transmission of infections and intoxications. The main concerns in the UK are scombroid fish poisoning, viral infections (associated with bivalve molluscs) and bacterial infections (associated with crustaceans). Paralytic shellfish poisoning (PSP) and red whelk poisoning occur sporadically, and ciguatera has started to appear associated with imported fish. The appearance in coastal waters of marine algae associated with diarrheic shellfish poisoning (DSP) has increased the likelihood of outbreaks of this toxic syndrome. The dinoflagellates causing neurotoxic shellfish poisoning and amnesic shellfish poisoning have not been detected in UK fishing waters but the fluctuating distribution of algal populations makes their appearance a possibility. The Food Hygiene Laboratory and the Torry research station of the Ministry of Agriculture, Fisheries and Food provide a reference service for scombrotoxin, ciguatera, DSP, PSP and red whelk poisoning in the UK.
Cross-Cultural Comparison↗
Kynurenic acid protects against gastroduodenal ulceration in mice injected with extracts from poisonous Atlantic shellfish.
1. Mice were treated with an extract prepared from poisonous Atlantic mussels. 2. Gastric and duodenal ulcers, duodenal hyperemia and peritoneal ascites resulted from administration of the shellfish extract, with an LD84 of 1.0 ml. 3. Kynurenic acid, an antagonist at excitatory amino acid receptors, protected significantly against gastroduodenal ulcers, ascites and hyperemia when given at 60 or 75 min post-extract. 4. It is likely that the gastrointestinal damage evoked by this extract is due to its domoic acid content and that kynurenic acid may prove useful against domoic acid-induced gastropathy.
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Detection of the marine toxins okadaic acid and domoic acid in shellfish and phytoplankton in the Gulf of Mexico.
Liquid chromatographic analyses of extracts from shellfish and phytoplankton from the Gulf of Mexico indicated the presence of the marine toxins okadaic acid (0.162 microgram/g shellfish) and domoic acid (2.1 pg/cell phytoplankter). These toxins are causative agents of diarrhetic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP), respectively. The presence of DSP and ASP toxins in a region with no previous record of outbreaks may indicate a potential for human poisoning under conditions appropriate for accumulation of these toxins in shellfish.
Animals↗
Neurotoxicity and lethality of toxic extracts from Atlantic coast shellfish.
1. HCl-extract of poisonous shellfish was injected i.p. into Swiss-Webster mice. 2. Behavioral effects (sluggishness, scratching, huddling, clonic convulsions, respiratory distress and mortality) were noted. 3. Infant mice were more sensitive than were the adults to XTRT toxicity. Estimated LD50 values were; adult: 34.8 ml/kg i.p., infant: 9.6 ml/kg i.p. 4. The mouse model of shellfish-toxicity offers the advantages of a degree of similarity with the human clinical situation and a rapid time course for screening antagonists against shellfish poisoning.
Aging↗
Phycotoxins in seafood--toxicological and chromatographic aspects.
Two typical clinical types of algae-related seafood poisoning have attracted medical and scientific attention: paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP). Therefore, it became necessary to establish methods for the evaluation of possible hazards caused by contamination of seafood with these phycotoxins. Bioassays with mice or rats are the common methods for the determination of the toxin content of seafood. However, biological tests are not completely satisfactory because of a lack of sensitivity and pronounced variations. Additionally, there is growing opposition against animal testing. Therefore, many efforts have been undertaken to determine phycotoxins by chromatographic methods. PSP determination is mainly based on high-performance liquid chromatographic (HPLC) separation by ion-pair chromatography followed by postcolumn oxidation of the underivatized toxins in alkaline solution and fluorescence detection. HPLC methods for the determination of the DSP toxins okadaic acid (OA) and dinophysistoxin-1 (DTX-1) are characterized by precolumn derivatization with 9-anthryldiazomethane (ADAM) and/or 4-bromomethyl-7-methoxycoumarin (Br-Mmc), followed by chromatographic separation of the DSP esters formed and fluorescence detection. The chromatographic methods discussed in this review allow the rapid, sensitive and non-ambiguous determination of individual species of the two most important phycotoxins in seafood, PSP and DSP.
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Respiratory effects of brevetoxin and saxitoxin in awake guinea pigs.
Ptychodiscus brevis toxin (brevetoxin) is associated with 'Florida red tide' and cause neurotoxic shellfish poisoning. Saxitoxin is the agent of paralytic shellfish poisoning. Clinical reports of human intoxication suggest that both toxins affect the respiratory system. The toxins were administered by slow intravenous infusion. The effects of the toxins on respiratory function of awake guinea pigs in a pressure plethysmograph were studied. Both toxins caused lactic acidosis of unknown etiology, which was compensated for by increased minute volume with brevetoxin (PbTx-3)- but not with saxitoxin-intoxicated animals. In general, brevetoxin increased ventilation, before respiratory failure, while saxitoxin had a depressive effect on ventilation. Airways resistance was not increased, nor was dynamic compliance decreased during intoxication, although the data suggest that respiratory system failure was the primary cause of death. The responses seen in these experiments are consistent with the dissimilar molecular actions of these toxins.
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Pelagic paralysis.
Three conditions that may occur after consumption of seafood--puffer fish poisoning, ciguatera, and paralytic shellfish poisoning--are caused by a group of poisons that block voltage-gated sodium channels in myelinated and non-myelinated nerves. The conditions cannot be distinguished clinically and so constitute an entity for which the name pelagic paralysis is proposed. Variations in the clinical features can be accounted for by large differences in the amount of toxin present in the seafood.
Animals↗
Comparison of liquid-junction and coaxial interfaces for capillary electrophoresis-mass spectrometry with application to compounds of concern to the aquaculture industry.
The application of capillary electrophoresis-mass spectrometry (CE-MS) to the analysis of compounds of concern to the aquaculture industry is reported. Two different approaches to coupling the CE column to an IonSpray atmospheric pressure ionization (API) interface, viz., a liquid-junction and a coaxial arrangement, are describe and compared with regard to ruggedness, ease of use, sensitivity and electrophoretic performance. The different injection modes used in three commercial capillary electrophoresis systems were also evaluated for their applicability to CE-MS. The use of CE-MS for the analysis of a variety of classes of antibiotics used in the fish aquaculture industry, such as the sulfonamides and their potentiators (e.g., trimethoprim), is demonstrated and was used to confirm the presence of these components in shellfish extracts at the low ppm level. CE-MS was also applied to the analysis of marine toxins such as saxitoxin and its analogues which are associated with paralytic shellfish poisoning, and also the toxins responsible for amnesic and diarrheic shellfish poisoning. Tandem mass spectrometry (MS-MS) was used to provide structural information on these analytes, and the ability to distinguish isomeric compounds based on their different migration and fragmentation characteristics using CE-MS-MS is demonstrated.
Anti-Bacterial Agents↗
Do saxitoxin-like substances have a role in scombrotoxicosis?
Evidence is presented which establishes that mackerel fed in captivity can, by relay from contaminated shellfish via sand eels, accumulate paralytic shellfish poisons (PSP) in the edible flesh at a level (250 micrograms saxitoxin equivalents per kg) similar to that in the contaminated shellfish. Data from ELISAs performed independently in two laboratories show that commercial mackerel fillets which have been associated with incidents of scombrotoxicosis contained 0.02-1.30 micrograms saxitoxin equivalents per kg, concentrations some two to four orders of magnitude below that normally detectable by the mouse bioassay. The doses, expressed as saxitoxin equivalents, administered inadvertently during volunteer testing of such fillets ranged up to 0.5 ng/kg bw, at least four orders of magnitude less than the fatal oral dose for an adult. The doses associated with the rapid induction of nausea/vomiting and/or diarrhoea, 0.11-1.0 ng/kg bw, could not be distinguished from the doses which failed to produce such symptoms in susceptible volunteers (up to 0.5 ng/kg bw). Factors that might explain this lack of correlation between dose (saxitoxin equivalents) and volunteer response are discussed along with previously published reports of PSP relay through the food web. It is suggested that the relay of algal toxins, particularly PSP, but possibly in combination with diarrheic shellfish poisons, may be responsible for scombrotoxicosis.
Animals↗
Histopathological studies on experimental marine toxin poisoning. I. Ultrastructural changes in the small intestine and liver of suckling mice induced by dinophysistoxin-1 and pectenotoxin-1.
Sequential ultrastructural changes were studied in mouse digestive organs after i.p. injections of dinophysistoxin-1 and pectenotoxin-1, causative agents of diarrhetic shellfish poisoning. Dinophysistoxin-1, a diarrheagenic substance, produced severe mucosal injuries in the small intestine within 1 hr after the administration of the toxin. The injuries were divided into 3 consecutive stages: extravasation of villi vessels, degeneration of absorptive epithelium and desquamation of the degenerated epithelium from the lamina propria. In contrast to dinophysistoxin-1, pectenotoxin-1, a non-diarrheagenic toxin from diarrhetic shellfish poisoning causative mussels, resulted in no abnormalities in the small intestine, but did cause characteristic liver injuries. Within 1 hr after the injection of pectenotoxin-1 numerous non-fatty vacuoles appeared in the hepatocytes around the periportal regions of the hepatic lobules. Electron microscopic observations with colloidal iron demonstrated that these vacuoles originated from invaginated plasma membranes of the hepatocytes.
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Protogonyaulax cohorticula, a toxic dinoflagellate found in the Gulf of Thailand.
Two clones of Protogonyaulax cohorticula were isolated from the Gulf of Thailand. The extracts of these clones killed mice with typical signs of paralytic shellfish poisoning. The toxicities corresponded to those of strongly toxic clones of P. tamarensis. In the HPLC and electrophoretic analyses, gonyautoxins and saxitoxin were detected. About 80% of the toxins consisted of gonyautoxin I. These results show that P. cohorticula is a toxic species of Protogonyaulax and that it is at least one of the causative organisms of paralytic shellfish poisoning in Thailand.
Animals↗
Preparation of monoclonal antibodies against okadaic acid prepared from the sponge Halichondria okadai.
Three murine monoclonal antibodies, OA-1, OA-2 and OA-3, against okadaic acid were prepared from hybridoma clones obtained by fusion of mouse 653 myeloma cells with mouse immune spleen cells sensitized to okadaic acid-ovalbumin conjugate. Each antibody reacted with dinophysistoxin-1 ( = 35-methylokadaic acid) as well as okadaic acid, but did not react with the other diarrhetic shellfish poisons or related compounds, such as 7-O-palmitoyl-okadaic acid (analogue of dinophysistoxin-3), pectenotoxin-1 and yessotoxin. A competitive inhibition enzymelinked immunosorbent assay which employed OA-3 antibody was performed and showed a sensitivity of about 10 ppb (10 ng/ml) for okadaic acid. This simple and time-saving ELISA assay system may be useful for the specific detection of diarrhetic shellfish poisons.
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[The problem of selective determination of PSP toxins in mussels].
Levels of paralytic shellfish poisoning (PSP) toxins in shellfish are routinely determined by mouse bioassay. In order to improve the qualitative and quantitative determination of PSP toxins, chromatographic techniques with fluorescence detection have been developed. These HPLC methods and the HPLC/MS coupling were used to determine a second PSP toxin which was found, in addition to saxitoxin, in canned Spanish mussels. These canned mussels were rejected in 1986 by the German food control because PSP concentrations were too high. It has been shown that these samples contained mainly dc-saxitoxin.
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Evaluation of laboratory performance of the AOAC method for PSP toxin in shellfish.
Laboratory performance of the official AOAC method for paralytic shellfish poison (PSP) toxin in shellfish was evaluated. Two series of naturally toxic shellfish split samples were distributed (15 in 1979 and 19 in 1982) to state shellfish-monitoring laboratories which participate in the National Shellfish Sanitation Program. The laboratories performed bioassays on duplicate 100 g portions of each 220 g split sample. Bioassays were consistent among the laboratories and compared favorably with those of previous studies.
Animals↗