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PubMed1980

Reduction of lipogenic enzymes by shellfish triglycerides in rat liver.

When rats were fed for 2 weeks on 3% fat diets containing 0.5 or 1%corbicula (Corbicula japonica PRIME), clam (Tapes japonica) or oyster (Callocorchina) triglycerides, serum and liver triglyceride levels were significantly lowered. The activities of hepatic glucose-6-phosphate dehydrogenase, malic enzyme and acetyl-CoA carboxylase were markedly reduced in the rats. Cholesterol synthesis by liver slices was also reduced. The results of immunochemical titrations and Ouchterlony double-diffusion analysis indicated that the decreases in the activities of acetyl-CoA carboxylase and glucose-6-phosphate dehydrogenase were due to decreases in the enzyme quantities. The shellfish triglycerides include a high percentage of long chain and polyunsaturated fatty acids, which are common to and characteristic of the three kinds of shellfish. They would be effective components in these observations.

Acetyl-CoA Carboxylase↗

PubMed2002

A polymerase chain reaction-based method for the detection of hepatitis A virus in produce and shellfish.

Outbreaks of gastroenteritis that are suspected to be of viral origin are on the rise. Thus, there is a need for regulatory agencies entrusted with food safety to develop adequate techniques for the detection of viruses in foods. We have established a general procedure for the detection of hepatitis A virus (HAV) in shellfish that, with minor modifications, is also applicable to fresh produce such as cilantro. Total RNA was isolated from shellfish or cilantro, followed by isolation of poly(A)-containing RNA. Because HAV genomic RNA contains a poly(A) tail, the isolation of poly(A)-containing RNA also enriches HAV genomic RNA. Reverse transcription was used to convert the RNA to cDNA, and then amplification was carried out by polymerase chain reaction (PCR). Reamplification with internal primers was used to improve the quality and the quantity of amplified DNA, allowing for post-PCR analysis such as sequence identification of the viral strain. With this procedure, multiple samples could be analyzed in four working days by a single trained individual. The nominal sensitivity of detection of the procedure was 0.15 TCID50 (50% tissue culture infective dose) per 0.62 g of tissue with a test virus. The direct RNA isolation protocol avoided pitfalls associated with whole-virus purification procedures by replacing virus precipitation steps involving polyethylene glycol and Procipitate with phenol extraction. The method is straightforward and reliable. We successfully used this procedure to detect naturally occurring HAV in clams involved in a gastroenteritis outbreak, as well as in cilantro artificially contaminated with a test virus.

Animals↗

PubMed1980

Identification of shellfish fatty acids and their effects on lipogenic enzymes.

The fatty acids which are common to and characteristic of shellfish, were identified by mass spectrometry and NMR spectral analyses as being: octadecatetraenoioc acid, eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid. When the fatty acids isolated by high performance liquid chromatography were separately intubated into rats, hepatic glucose-6-phosphate dehydrogenase (EC 1.1.1.49), malic enzyme (EC 1.1.1.40) and acetyl-CoA carboxylase (EC 6.4.1.2) were reduced more effectively as compared with linoleic acid intubation. These enzymes were reduced most markedly by eicosapentaenoic acid-intubation. The fatty acids seem to be effective components in reduction of triacylglycerol and lipogenic enzyme levels in rats fed on shellfish.

Acetyl-CoA Carboxylase↗

PubMedDate not supplied

Detection of DSP-toxins, okadaic acid, and dinophysis toxin-1 in shellfish by serine/threonine protein phosphatase assay.

A relatively rapid protein phosphatase-based assay was developed for detecting okadaic acid in extracts of shellfish, using oysters (Crassostrea virginica) as a model. The assay has good sensitivity, detecting okadaic acid in crude methanolic extracts of oysters at > or = 4 ng/mL (> or = 0.1 ng/assay). Assay accuracy for detecting toxic shellfish was validated through a series of spike recovery experiments. In more than 320 assessments, all oysters containing toxic amounts of okadaic acid (> or = 0.2 microgram/g) were detected. Results of analysis of the same extract by phosphatase assay and liquid chromatography gave very high correlation.

Animals↗

PubMed1997

A simple procedure for sulfation and 35S radiolabelling of paralytic shellfish poisoning (PSP) gonyautoxins.

A method is described to sulfate PSP toxins at various positions in the molecule and to prepare 35S labelled compounds using H2(35)SO4 in the presence of dicyclohexylcarbodiimide (DCC). The 11-sulfates of saxitoxin and neosaxitoxin, known as gonyautoxins, are often the most abundant of the PSP toxins in algae and contaminated shellfish. Receptor site binding and antibody assays based on these analogues should, therefore, better reflect toxicity than those in which saxitoxin is used. Although the specific activity of 35S-gonyautoxins is lower than that of commercially available 3H-saxitoxin, the label is strongly bound and is not lost through proton exchange with water as occurs with tritiated saxitoxin. The labelling procedure is rapid, inexpensive and can be done on a small scale. Sulfate can be removed from the 11-position of GTX's in methanolic-HCl and from the 21-position by mild acid hydrolysis and H2(35)SO4 added in 5-10-fold excess. Addition or exchange occurs rapidly on mixing DCC in dimethylformamide with dry toxin and sulfate. Reaction conditions were optimized and reaction products identified by capillary electrophoresis, autoradiography and ionspray mass spectrometry. Together with methods for selective removal of sulfate, the sulfation reaction provides an additional way to prepare some of the naturally occurring derivatives of saxitoxin, many of which are sulfates.

Animals↗

PubMed1995

Sheep mortality associated with paralytic shellfish poisons from the cyanobacterium Anabaena circinalis.

This is the first report of sheep mortalities associated with paralytic shellfish poisons (PSPs) from the cyanobacterium Anabaena circinalis Rabenhorst. Fourteen sheep died within 150 m of a farm dam containing a dense bloom of A. circinalis. Extracts from both the cyanobacterium and small intestine from a dead ewe were analysed by high-performance liquid chromtography (HPLC) and found to contain PSPs. The toxin profiles of the cyanobacterium contained a high proportion of C-toxins (70%), whereas toxins in the small intestine content were dominated by gonyautoxin 5 (87%). This observation could be explained by desulfation of the C-toxins in the gut of the sheep. The LD100 of bloom material calculated from HPLC data was consistent with mouse bioassay data (12-25 mg/kg). The symptoms of affected sheep, mouse bioassay data, coupled with HPLC analysis of toxins from the bloom samples and the intestine contents, and the absence of other cyanobacterial alkaloid toxins, indicate that PSPs were responsible for the deaths of the sheep.

Animals↗

PubMed1997

Evidence for production of paralytic shellfish toxins by bacteria associated with Alexandrium spp. (Dinophyta) in culture.

A substantial proportion of bacteria from five Alexandrium cultures originally isolated from various countries produced sodium channel blocking (SCB) toxins, as ascertained by mouse neuroblastoma assay. The quantities of SCB toxins produced by bacteria and dinoflagellates were noted, and the limitations in comparing the toxicities of these two organisms are discussed. The chemical nature of the SCB toxins in selected bacterial isolates was determined as paralytic shellfish toxins by pre- and postcolumn high-performance liquid chromatography, capillary electrophoresis-mass spectrometry, and enzyme immunoassay.

Animals↗

PubMed2002

An outbreak of diarrhoeic shellfish poisoning in Antwerp, Belgium.

In Antwerp, Belgium, 403 cases of diarrhoeic shellfish poisoning were reported after consumption of blue mussels. Symptoms included diarrhoea, vomiting, abdominal pain, and nausea. The analysis of faecal specimens from patients allowed diagnosis exclusions for bacteria and viruses. Mouse-assays revealed the presence of biotoxins specific of dinoflagellates, which were identified and quantified by LC-MS. The mussels were imported from Denmark, and were part of a batch presenting high concentrations of okadaic acid above the regulatory limits.

Adolescent↗

PubMed2002

First paralytic shellfish poison (PSP) infestation of bivalves due to toxic dinoflagellate Alexandrium tamiyavanichii, in the southeast coasts of the Seto Inland Sea, Japan.

The mussel Mytilus edulis and the cultured ark shell Anadara broughtonii in the southeast coasts of the Seto Inland Sea were contaminated with paralytic shellfish poison (PSP) following the appearance of the dinoflagellate Alexandrium tamiyavanichii in early December 1999. A. tamiyavanichii plankton collected around the Straits of Naruto on December 3, 1999 showed PSP toxicity, of which 83 mol% was accounted for by GTX2, GTX3 and GTX4. Its specific toxicity was 112.5 fmol/cell, and one MU was equivalent to 7,200 cells. Toxicity values at the beginning of toxification were 4.7 MU/g for the ark shell and 7.3 MU/g for the mussel. In the former, the value remained at almost 4 MU/g, resulting in prohibition of marketing for about two months. In the latter, it sharply decreased to less than 4 MU/g. These bivalves collected during the toxification period were dissected into five tissues, mantle, adductor muscle, hepatopancreas, gills and "others", and submitted to high-performance liquid chromatography (HPLC). The cultured ark shell accumulated GTX2, GTX3 and STX as major components and GTX1, GTX4, GTX5, neoSTX, dcSTX and PX1-3 (C1-C3) as minor ones. The amount of GTX3 decreased with time, while STX tended to increase. At the early stage of PSP toxification, toxins were accumulated in the gills and "others", most of which were quickly detoxified. On the other hand, PSP of the toxified mussel consisted of GTX4 as a main component, and GTX1, GTX2, GTX3, GTX5, STX and PX1-2 (C1-C2) as minor ones. Its toxin composition pattern was similar to that of the ingested causative plankton. Its total toxin decreased soon after disappearance of the dinoflagellate. During the decrease of toxicity, PSP tended to be retained in the hepatopancreas, resulting in accumulation of 50 mol% of total toxin.

Animals↗

PubMed1989

Infectious and toxic syndromes from fish and shellfish consumption. A review.

Primary care physicians care for large numbers of patients presenting with "food poisoning" or gastroenteritis. When a patient who presents with acute gastrointestinal illness, especially in conjunction with neurologic or cutaneous symptoms, is evaluated, the history should focus on past seafood consumption (particularly raw or undercooked seafood). The infectious syndromes are generally self-limited and respond to supportive care; exceptions are those caused by Vibrio cholerae and Vibrio vulnificus, which may be fatal in severe cases. The toxic syndromes are uncommon and fall into two categories: the histaminelike syndrome of scombroid poisoning and the neurotoxic syndromes, including ciguatera, paralytic shellfish poisoning, and puffer fish poisoning. Recognition of these clinical entities may lead to more appropriate management and preventive measures.

Animals↗

PubMed1983

High pressure liquid chromatographic determination of toxins associated with paralytic shellfish poisoning.

A high pressure liquid chromatographic procedure is described for assay of toxins associated with paralytic shellfish poisoning (PSP). The method is applicable to saxitoxin, neosaxitoxin, gonyautoxins I through IV, and their sulfocarbamoyl derivatives. Toxins are separated on a bonded phase cyano column and detected by fluorescence following alkaline oxidation (NH+4 and periodic acid). The utility of the HPLC procedure for research and monitoring is discussed.

Animals↗

PubMed1996

Simultaneous occurrence of diarrhetic and paralytic shellfish poisoning toxins in Spanish mussels in 1993.

Mussel aquaculture is an important industry for the Galician Rias, located in northwestern Atlantic coast of Spain. Since 1976 this region has been seriously affected by incidents of paralytic and diarrhetic shellfish poisoning (PSP and DSP). A particularly bad episode occurred in 1993, when the toxic event lasted for an unusually long period. Many people were stricken ill with unusual symptoms. In this paper we report on the chemical analysis of toxic 1993 mussel samples, using the techniques of liquid chromatography and capillary electrophoresis coupled with mass spectrometry. These analyses revealed a very complex toxin profile, with both PSP and DSP toxins present. Two DSP toxins, okadaic acid and DTX2, were observed, while the primary PSP toxins were B1 and the decarbamoylated derivatives of saxitoxin, GTX2 and GTX3. Small amounts of saxitoxin and other as yet unidentified PSP toxins were observed.

Animals↗

PubMed2002

Superabsorbent materials from shellfish waste--a review.

Increasing global demand for improved absorbent materials for body fluids in disposable medical and personal-care articles creates an incentive for new basic research and development of efficient absorbent materials and systems with additional benefits such as biodegradability or certain biomedical functions. Highly absorbing materials based on polyelectrolyte polymers can absorb up to 50 grams of body fluid per gram of dry mass. Currently available synthetic superabsorbents are not biodegradable in landfills and do not offer any value-added functions to personal and medical-care products. Various academic and industrial research groups have put considerable amounts of effort and resources toward development of new absorbent materials from natural polymers, which would decompose in landfills. The basic substrates in these studies have been mainly polysaccharides, particularly cellulose and starch. The most common approach has involved converting these polymers into carboxymethyl derivatives followed by structural cross-linking. Commercial synthetic superabsorbent polymers as well as those derived from cellulose and starch are essentially polyanionic. On the other hand, polycationic absorbers seem to have potential functional advantages over the polyanionic counterparts. Chitin is the second abundant natural polymer, whose main derivative, chitosan, becomes polycationic in acid media. Currently, the main source of this polysaccharide is shellfish waste. This review provides basic information about new superabsorbent materials based on chitosan salts, their properties and preparation.

Absorbent Pads↗

PubMed1998

A high-throughput, microtiter plate assay for paralytic shellfish poisons using the saxitoxin-specific receptor, saxiphilin.

An isoform of the paralytic shellfish poison (PSP)-specific receptor saxiphilin, from the tropical centipede Ethmostigmus rubripes, was used as the basis for a radiometric, high-throughput, microtiter plate assay for this group of toxins. Characterization of the assay revealed that it was able to detect several representatives from the various structural PSP subgroups and yet was insensitive toward tetrodotoxin. To test the utility of the assay as a seafood toxin-monitoring tool, the assay was subjected to a variety of marine organism extracts, some of which were known to contain PSPs, and whole extract toxicity expressed as STX equivalents (STXeq) was measured by two methods: First, by comparison of values from a screening assay with a standard STX inhibition curve and, second, for highly active extracts, by calculation using the IC50 from a full inhibition curve of the extract. For extracts which could be quantified by both methods, there was almost 100% correlation between the derived values. STXeq derived by both methods from the bioassay highly correlated with absolute toxin quantities from HPLC analysis.

Amphibian Proteins↗

PubMed1981

1,3,5-Trichloro-2-(4-nitrophenoxy)benzene in fish, shellfish, and seawater in Tokyo Bay, 1977-1979.

Concentrations of 1,3,5-trichloro-2-(4-nitrophenoxy)benzene (CNP) were measured in goby-fish, sea bass, shellfish, and seawater samples collected in the coastal waters of Tokyo Bay. The concentrations of CNP found in goby-fish were in the range of 2.6 to 91,400 ppb in liver, 0.1 to 360 ppb in muscle, trace to 2,900 ppb in short-necked clam, and not detectable to 1.9 ppb in seawater. Although the concentrations in the samples varied with time and place of sampling, the maximum levels were found in the samples obtained in May or June of 1977, 1978, and 1979.

Animals↗

PubMed1993

Environmental analysis of polychlorinated terphenyls: distribution in shellfish from the Ebro Delta (Mediterranean).

Polychlorinated terphenyls (PCTs) have characteristics almost identical with those of polychlorinated biphenyls (PCBs) and have been used for analogous applications, but only sporadic reports of the occurrence of PCTs in the environment have been published. High-resolution gas chromatography with electron-capture detection (HRGC-ECD) and mass spectrometric detection in the selected ion monitoring mode was used to analyse samples for PCTs. The homologue distribution of Aroclor 5432, 5460, Leromoll 141 and the PCTs in samples of shellfish from the Ebro Delta (Catalonia, Spain) was established, taking into account the contribution of the [M-Cl2]+ fragments. Quantification was achieved by HRGC-ECD. Concentrations were between 790 and 3 ng/g (dry mass).

Animals↗

PubMed1994

Comparison of UV absorption and electrospray mass spectrometry for the high-performance liquid chromatographic determination of domoic acid in shellfish and biological samples.

Domoic acid, a neurotoxic amino acid produced by the marine diatom Nitchia pungens multiseries, was determined in samples of anchovies, razor clams, mussels, crab, rat serum, urine and feces by HPLC with UV absorption and electrospray (ESI) mass spectrometric (MS) detection. Shellfish samples were extracted with methanol-water followed by clean-up of the extracts with solid-phase extraction cartridges (strong anion or strong cation exchange). An aliquot of the fraction containing the domoic acid was analysed by HPLC. HPLC column size, mobile phase composition and flow-rate were selected so that essentially the same conditions could be used for both HPLC-UV and HPLC-ESI-MS with selected ion monitoring (SIM) determinations. These included the use of acetonitrile-water-formic acid as the mobile phase, at a flow-rate of 0.2 ml/min (split 13:1 for HPLC-ESI-MS-SIM, 10 microliters/min to the mass spectrometer). The results indicated that extracts found positive by the HPLC-UV method could be readily confirmed directly by HPLC-ESI-MS-SIM without additional sample treatment down to levels of 0.1 micrograms/g of domoic acid. This study demonstrates the use of HPLC-ESI-MS-SIM for the routine confirmation of domoic acid in a wide variety of samples.

Animals↗

PubMed1996

Liquid chromatographic determination of okadaic acid and dinophysistoxin-1 in shellfish after derivatization with 9-chloromethylanthracene.

The reagent 9-chloromethylanthracene was evaluated for derivatization of the diarrhetic shellfish poisons, okadaic acid and dinophysistoxin-1 (DTX-1), to form fluorescent products separable by liquid chromatography. The toxins were reacted with the reagent in acetonitrile in the presence of tetramethylammonium hydroxide for 1 h at 90 degrees C. The products were purified by using two silica solid-phase extraction cartridges before being determined by reversed-phase liquid chromatography with fluorescence detection. The results are comparable to those obtained using 9-anthryldiazomethane (ADAM) for okadaic acid and DTX-1 in mussel tissue. Detection limits were estimated to be about 70-100 ng/g hepatopancreas (equivalent to 12-20 ng/g whole tissue) for each toxin.

Animals↗