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PubMed2000

Comparative efficiencies of different non-toxic microalgal diets in detoxification of PSP-contaminated oysters (Crassostrea gigas Thunberg).

Experimental PSP contamination of adult Pacific oysters (Crassostrea gigas) by the toxic dinoflagellate Alexandrium minutum Halim (120 cells.mL-1 continuously maintained in each flume) was carried out in a recirculated seawater system to obtain toxin levels above the safety threshold. In these conditions, 150 to 300 micrograms STX.eq.100 g-1 of shellfish tissues were produced at 16 degrees C within 8 to 15 days, corresponding to field values observed along French coasts. Diets based on non-toxic flagellates or diatoms were then used to detoxify the contaminated oysters. Despite large individual variations in toxin levels at the end of the contamination period, detoxification times were of the same order of magnitude (3 to 4 days), reaching a toxin level equal to or less than the safety threshold. These variations were most likely related to marked individual variability in valve and/or clearance activities. No significant differences in detoxification rates were found when oysters were fed Isochrysis galbana, Tetraselmis suecica, Thalassiosira weissflogii, or Skeletonema costatum. The different biochemical compositions of each algal species appeared to have no significant effect on detoxification rates. GTX2/GTX3 were the dominant compounds found in shellfish tissues during depuration, whereas C toxins were quite low (< 2 micrograms STX.eq.100 g-1) and STX or NeoSTX undetectable. These results do not suggest any bioconversion of paralytic toxins but indicate good correlation between the toxin composition of Alexandrium and oyster tissues.

Animals↗

PubMed1975

Determination of altosid insect growth regulator in waters, soils, plants, and animals by gas-liquid chromatography.

Residues of isopropyl (2E,4E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate (Altosid) insect growth regulator are determined in waters, soils, plants, milk, eggs, fish, shellfish, poultry and cattle tissues, blood, urine, and feces. Acetonitrile is the primary extraction solvent for all samples. Residues are extracted by high-speed blending followed by vacuum filtration. Fatty extracts are subjected to cold-temperature precipitation and filtration. Samples are cleaned up by petroleum ether partitioning and Florisil and neutral alumina chromatography. The concentrated eluants are analyzed by gas-liquid chromatography (GLC) on columns of differing polarity, using hydrogen flame ionization detectors. The identity of suspected residues is confirmed by additional GLC and by mass fragmentography. The lower limits of detection were: water samples, 0.0004-0.001 ppm; soils, blood, and urine, 0.001 ppm; forage grasses, forage legumes, and rice foliage, 0.005 ppm; and milk, eggs, fish, shellfish, poultry and cattle tissues, and feces, 0.010 ppm.

Acetonitriles↗

PubMed2002

Comparison of copper levels in runoff from fresh-market vegetable production using polyethylene mulch or a vegetative mulch.

Runoff from tomato (Lycopersicon esculentum Mill.) production with polyethylene mulch has been implicated in the failure of commercial shellfish farms in the Mid-Atlantic Region of the United States. Copper, applied in the form of copper hydroxide, is the most widely used fungicide-bactericide for control of tomato diseases and recently has been detected in the Chesapeake Bay (USA) watershed. Elevated levels of copper have been shown to have adverse effects on shellfish, finfish, and other aquatic organisms. This research evaluates the off-site movement of copper with the dissolved phase and the particulate phase of runoff from controlled field plots containing tomato plants grown in either polyethylene mulch or a vegetative mulch, hairy vetch (Vicia villosa Roth.). Overall, runoff collected from polyethylene mulch plots contained significantly (p < or = 0.05) greater loads of dissolved- and particulate-phase copper than runoff from hairy vetch mulch plots. However, the loss of copper associated with the particulate phase was significantly greater (p < or = 0.05) than that associated with the dissolved phase of runoff from both mulch treatments, with the particulate phase accounting for more than 80% of the copper loads. The reported toxicity of copper to aquatic organisms and the greater runoff volume, soil loss, and off-site loading of copper measured in runoff from the polyethylene mulch suggests that this management practice is less sustainable and may have a more harmful impact on aquatic ecosystems.

Agriculture↗

PubMed2004

Use of sodium transfer tissue biosensor (STTB) for monitoring of marine toxic organism.

A highly sensitive sodium (Na+) transfer tissue biosensor (STTB) was designed using a frog bladder membrane to measure paralytic shellfish poisons (PSP). The STTB consists, of a Na+ electrode covered by the membrane, which was then integrated into a flow-through system for continuous measurements. In the absence of Na+ channel blocker, active transfer of Na+ occurred from inside to outside across the frog membrane. When the STTB was used to measure the Na+ -dependent dissociation of PSP, it was able to detect PSB at a level contained in a single cell. However, 5 fg or higher (100 cells or more) is needed for accurate and reproducible measurements. The toxicity obtained by the STTB was significantly correlated (r = 0.9449) to that determined by the HPLC. Therefore, the simple method of the STTB can be used not only to detect a low level PSP in toxic plankton populations, but also to monitor poisons in shellfish.

Animals↗

PubMedDate not supplied

Immunobiosensor detection of domoic acid as a screening test in bivalve molluscs: comparison with liquid chromatography-based analysis.

A rapid and sensitive immuno-based screening method was developed to detect domoic acid (DA) present in extracts of shellfish species using a surface plasmon resonance-based optical biosensor. A rabbit polyclonal antibody raised against DA was mixed with standard or sample extracts and allowed to interact with DA immobilized onto a sensor chip surface. The characterization of the antibody strongly suggested high cross-reactivity with DA and important isomers of the toxin. The binding of this antibody to the sensor chip surface was inhibited in the presence of DA in either standard solutions or sample extracts. The DA chip surface proved to be highly stable, achieving approximately 800 analyses per chip without any loss of surface activity. A single analytical cycle (sample injection, chip regeneration, and system wash) took 10 min to complete. Sample analysis (scallops, mussels, cockles, oysters) was achieved by simple extraction with methanol. These extracts were then filtered and diluted before analysis. Detection limits in the ng/g range were achieved by the assay; however, the assay parameters chosen allowed the test to be performed most accurately at the European Union's official action limit for DA of 20 microg/g. At this concentration, intra- and interassay variations were measured for a range of shellfish species and ranged from 4.5 to 7.4% and 2.3 to 9.7%, respectively.

Animals↗

PubMedDate not supplied

Hepatitis A in Italy: epidemiology and suggestions for control.

Seroepidemiologic and surveillance data show that hepatitis A is declining in both Northern and Southern Italy, in the latter the decline has been more recent. Every year about two thousand cases of acute disease occur. Shellfish consumption and travel to endemic areas are at present the most important risk factors in Italy. Use of immunoglobulin is effective in controlling outbreaks and preventing hepatitis A among travellers. Active immunization for travellers to endemic areas will be recommended, when a vaccine will be available. Adequate cooking of shellfish is at present the only advisable measure to prevent the risk represented by their consumption. Acute morbidity and the occurrence of outbreaks suggest the need to keep our attention on hepatitis A infection in Italy.

Adolescent↗

PubMed1989

Case study: mariner's TB.

Mycobacterium marinum causes tuberculosis in fish and shellfish and cutaneous lesions in humans. It is transmitted from fish to humans by inoculation. The case presented involved a nodule on the wrist and was misdiagnosed as arthritis; the nodule was excised. Symptoms of tuberculosis persisted over a 2-year period. This case study can be generalized to a population of workers in the seafood industry, water hobbyists, and fish and shellfish enthusiasts. Education and research is needed to inform and protect populations at high risk for this disease.

Animals↗

PubMed1978

Viruses in water.

Attention is drawn in this paper to the increasing problem of viral contamination of water and shellfish, particularly since growing demands for available water resources by a rising world population and expanding industry will make the recycling of wastewater almost inevitable in the future. The problem of eliminating viruses pathogenic for man from water is considered in the light of present water treatment procedures, which are often inadequate for that purpose. Man may be exposed to waterborne viruses through the consumption of contaminated water, shellfish, or crops, as a result of recreational activities involving water, or from aerosols following the spraying of crops with liquid wastes. Physical and chemical methods of eliminating viruses from water are discussed.

Humans↗

PubMed1986

[Public health impact of adsorption of enteroviruses on ocean and river sediments].

Fixation of enteroviruses in sands, ocean sediments, and river mud constitutes a very real public health risk. The authors review the physicochemical and biological mechanisms of virus attachment to particles. Rates of adherence frequently reach 90 to 100%, especially in montmorillonites and sands. Studies devoted to microorganism adherence are mentioned. Attachment of enteroviruses to particles in suspension, to bacteria and other microorganisms--all becoming vectors--is described. Also reviewed is the manner in which these pathogenic substances are disseminated in the environment, especially at beaches, recreational areas and shellfish breeding areas. Greater vigilance to the dangers is advocated on the part of public health authorities, those responsible for environmental salubrity and for shellfish grounds.

Disease Reservoirs↗

PubMed1986

Salmonellosis in the marine environment. A review and commentary.

Marine cetaceans (whales and dolphins), pinnipeds (seals and sea lions), reptiles (turtles and crocodyles), fish and shellfish, and fish-eating birds have been found to harbor salmonellae. In some of these animals, clinical salmonellosis has been demonstrated, but in many cases, the isolated salmonellae may have been an opportunistic pathogen with the illness or death of the host due to other causes. On the basis of the few reports in the literature, marine reptiles (turtles and crocodyles), fish, and shellfish appear to be passive carriers of salmonellae and demonstrate no clinical disease. All of these animals constitute a potential source of salmonellosis in man and his domestic animals. The role of wild and domestic terrestrial animals and fresh water aquatic animals in the transmission of salmonellosis to man has been recognized for many years. The situation with regard to the marine (saltwater) animals has never been adequately investigated or reported. In the past, much reliance has been placed on the ability of saline waters to inhibit or destroy human pathogens, including the salmonellae. Whether this effect is chemical, physical or biological has been studied since the late nineteenth century, and the investigators have found a number of factors affecting both the inhibition and stimulation of growth of salmonellae in saline waters. Salmonellae have been isolated from or found to survive in seawater with salinities as high as 3.5 percent. Marine animals in many parts of the world have been found harboring salmonellae.

Animals↗

PubMed1974

Ecology and epidemiology of Vibrio parahaemolyticus on the coast of Togo.

Following the identification of V. parahaemolyticus as an important agent of choleralike gastroenteritis in Togo, studies to establish the natural reservoirs of these bacteria were performed in 1972-73. Whereas V. parahaemolyticus was rarely found in water from the Atlantic ocean, the lagoons along the coast proved to be important reservoirs. The incidence of halophilic vibrios was correlated with the salinity of these waters, which is subjected to seasonal changes with the highest sodium chloride concentration at the end of the dry season. Examination of fish and shellfish samples confirmed these results: V. parahaemolyticus was isolated from only 0.5% of freshly caught fish from the Atlantic ocean but occurred in 47.3% of fish and shellfish samples from the lagoons. A still higher occurrence was encountered in specimens purchased in the markets, with 14.3% of sea fish samples and 67.7% of specimens originating from the lagoons being positive. Since lagoons and lakes with brackish water are typical of all the coastal areas between Nigeria and Ivory Coast it is likely that V. parahaemolyticus is a widespread pathogen on the coast of West Africa.

Animals↗

PubMed1979

Cholera in the Gilbert Island. I. Epidemiological features.

An explosive epidemic of cholera due to Vibrio cholerae, biotype El Tor, serotype Inaba, was centered on the coral atoll of Tarawa, Gilbert Islands. This outbreak was a unique experience in the South and Central Pacific region. The principal mode of spread during the peak of the outbreak was probably through contamination of the main water supply. Tarawa lagoon water and shellfish were found to be contaminated with V. cholerae and ingestion of raw fish and shellfish from the lagoon also served as a source of transmission. This outbreak raises the concern of Rother outbreaks of cholera occuring on remote and poorly equipped Pacific islands where the environmental circumstances are conducive to cholera spread.

Antibodies, Bacterial↗

PubMed1981

Polychlorinated biphenyls in clams and oysters from New Bedford Harbor, Massachusetts, March 1978.

Polychlorinated biphenyl (PCB) concentrations in clams (Mercenaria mercenaria) and oysters (Crassostrea virginica) from 17 stations of the western and New Bedford Harbor areas of Buzzards Bay, Massachusetts, clearly show that the New Bedford Harbor area is severely polluted. Up to 5 ppm PCBs (dry weight) were found in shellfish tissue. The most likely sources of the PCBs are chronic releases from two electrical component manufacturers in New Bedford. Close proximity of the shellfish to the source of input is indicated by a high relative abundance of the di-, tri-, and tetrachlorobiphenyls. The data suggest that the New Bedford Harbor area should be considered, along with the Hudson River and Chesapeake Bay, one of the major sources of PCB inputs to the northeastern United States coastal area.

Animals↗

PubMedDate not supplied

Modified immunoassays for polyether toxins: implications of biological matrixes, metabolic states, and epitope recognition.

Polyether marine toxins are responsible for the seafood intoxication phenomena known as neurotoxic shellfish poisoning (due to brevetoxins), ciguatera (due to ciguatoxin), and diarrheic shellfish poisoning (due to okadaic acid). Using traditional techniques of hapten (pure toxin) conjugation to protein to create complete antigen, animal immunization and antibody isolation, and specific antibody subpopulation purification, discriminating antibodies have been isolated that detect brevetoxins and ciguatoxin, but not okadaic acid, in a dose-dependent fashion. Using microorganic chemistry and purified toxins, a unique set of tools has been created for the study of polyether ladder toxin accumulation; depuration; and specific site localization in tissues, food sources, and clinical samples. Developed test protocols can detect toxin in dinoflagellate cells, in extracts from food sources, in seawater and culture media, and in human serum samples. Enzyme-linked immunosorbent assay protocols developed for eventual collaborative testing have been successful in limited applications within the laboratory (correlation coefficient of 0.92 excluding 2 outliers), and alternative formats are being developed to optimize the basic test for use in research laboratories, regulatory laboratories, and field inspections.

Antibodies↗

PubMed1993

Isolation and characterization of Aeromonas from seafoods in Taipei.

A total of 124 fresh seafoods and 158 processed seafoods collected from the retail markets and supermarkets in Taipei were tested for the contamination with motile Aeromonas spp. Of the fresh seafoods analyzed, 88% displayed the presence of Aeromonas. The isolation rates of various samples were as follows: 100%, freshwater fish; 95%, seawater fish; 78%, fish fillets; 84%, shrimp and crab of the crustacea group; 83%, bivalve shellfish and 84%, non-bivalve shellfish of the mollusca group, and 100%, seaweed. Of the 158 processed seafoods, 11% were contaminated by Aeromonas. The isolation rates were as follows: 0%, canned, dried, or frozen fresh seafood; 18%, salted seafood; 30%, fish cake; 7% vacuum-packaged fish cakes; 14%, frozen seafood dumplings; 8%, cooked seafoods. One hundred and eighty-three Aeromonas strains isolated in this survey were characterized to species level and tested for their ability to produce beta-hemolysin. Ninety-eight percent (98%) of the A. hydrophila produced beta-hemolysin on 5% blood agar, 94% of the A. sobria and 33% of the A. caviae produced beta-hemolysin. Thus it is likely that fresh seafoods are potentially significant sources of the virulent Aeromonas species and may play an important role in the epidemiology of Aeromonas-associated gastroenteritis.

Aeromonas↗

PubMed1993

Vibrio vulnificus from raw oysters. Leading cause of reported deaths from foodborne illness in Florida.

Seventy-two cases of Vibrio vulnificus infection from raw oysters were reported from 1981-1992; 36 (50%) patients died, making this infection the leading cause of reported deaths from foodborne illness in Florida. The bacterium naturally occurs in coastal waters and may contaminate legally harvested and properly handled shellfish. Infection, usually by ingestion of contaminated raw oysters, can cause severe illness especially in individuals with preexisting liver disease. They are at 80 times greater risk of illness and over 200 times greater risk of death. The case fatality rate (63%) among patients with liver diseases was over 2.5 times the rate (23%) among those without liver disease. Infections usually occurred during the warm weather months and presented as fulminant septicemia, often complicated by necrotizing cutaneous lesions. Early treatment with antibiotics, debridement and amputation when necessary may improve survival. Prevention relies upon educating patients regarding risk and thorough cooking of shellfish.

Adult↗

PubMed1997

Protein phosphatase in neuroblastoma cells: [3H]cantharidin binding site in relation to cytotoxicity.

Protein phosphatase 2A (PP2A) plays a central role in essential phosphorylation-dependent signal transduction pathways. It is also a principal target for many natural toxicants (cantharidin, microcystins, diarrhetic shellfish poisons) and a synthetic herbicide (endothall). This study develops a cellular model to explore the toxicology of PP2A inhibitors by use of a [3H]cantharidic acid ([3H]CA) ligand binding assay to quantify interactions at the toxicant site and cell viability to evaluate in vivo toxicity. Mouse neuroblastoma (N1E-115) cells are similar to mouse brain with respect to the affinity (12-15 nM), number (B(max), 9-22 pmol/mg protein) and ligand specificity of this binding site. In addition, the competitive potency of ten analogs of CA (including endothall) and two potent diarrhetic shellfish poisons (okadaic acid and calyculin A) is correlated (r2 = .9) with and therefore predictive of their cytotoxicity. The only exception is microcystin LR which is a potent inhibitor at the binding site but is not cytotoxic, possibly reflecting a lack of cellular uptake. ATP and several other phosphorus-containing bifunctional acids inhibit [3H]CA binding by phosphorylation-independent pathways; pyrophosphate apparently acts as a competitive inhibitor. Mn++ and five other divalent cations are also inhibitors with a unique action of Mn++ at 25 to 50 microM in increasing [3H]CA binding, which suggests a specific role in PP2A function. Neuroblastoma cells are therefore suitable to study the mechanisms by which the toxicant, ATP and Mn++ binding sites regulate PP2A activity and cell physiology.

Animals↗

PubMed1998

[Biological testing of cyclic acetaldehydes and their oxidation products using mollusks].

Toxicity of cyclic acetaldehyde and the affined compounds was studied in freshwater shellfish Planorbis spirorbis in laboratory conditions. Chronic threshold concentrations of the acetaldehyde appeared to depress the increase in total mass and to lower the content of hemolymph. Functional state of the shellfish cells changed--the share of cell deformations reaches 57%. The phenomena are traced to disorders in hemocytes membrane permeability, changes in cellular composition of hemolymph, decreased share of basophilic and increased share of oxyphilic cells in hemolymph. Thus, studies of toxicity should include both traditional examination and thorough hematologic evaluation.

Acetaldehyde↗