Codfish Research Articles

Determination of methylmercury in fish by headspace-gas chromatography with microwave-induced-plasma detection

Some additional experiments checking out the extraction method recently developed for the determination of MeHg in biological samples by Headspace Gas Chromatography with Microwave Induced Plasma atomic emission spectroscopy detection were performed. In this method, the MeHg is cleaved from the biological tissue by H2SO4 and by addition of iodoacetic acid converted to the iodide form. These reaction steps take place in a closed headspace vial. The H2SO4 concentration and the sample matrix have an important influence on the recovery of the MeHg from the sample and these effects are discussed. The method was then applied to the determination of MeHg in cod fish caught in the North Sea. Levels found ranged from 0.13 to 0.63 μg g−1 dw with a mean of 0.33 μg g−1 on the 25 samples analyzed. The total Hg content of these samples was also determined by Cold Vapour Atomic Absorption Spectrometry, and all data pooled ranged from 0.19 to 0.90 μg g−1 with a mean of 0.40 μg g−1. A study of the ratio MeHg/total Hg revealed that MeHg always constituted more than 60 % of the total Hg level, with a mean of 83 % on the 25 samples. The percentage MeHg did not increase or decrease markedly when the total Hg content increased. It could be concluded that these North Sea samples are not much contaminated by Hg and are surely suitable for consumption.

A neural-network-based system to recognize parasites/seal worms on cod fish images

A requirement for an intelligent system to automatically sort parasitic/sealworm infested cod fish fillet from good normal cod fish fillet has been recognized. 1 Hence, a neural-network-based system in combination with image processing techniques has been developed to recognize, detect and locate these parasites in cod fish fillets. This system combines the advantages of the massive parallelism of the neural network with image-processing procedures to recognize various attributes or characteristics of parasitic/sealworm patterns as derived from cod fish fillet images produced currently by backlighted photographs. The generalized neural network backpropagation supervised learning algorithm is used for the investigation of the steepest descent and the conjugate gradient optimization methods. 2 The cod fish fillet image data is manipulated so as to find the most efficient form, processed or unprocessed, before presentation to the neural network. This paper reports on investigations and analysis carried out and then presents a proposed intelligent system to automatically separate parasitic/sealworm-infested cod fish fillets from normal cod fish fillets.

Purification and characterization of purine nucleoside phosphorylase from Proteus vulgaris

Purine nucleoside phosphorylase was isolated and purified from cell extracts of Proteus vulgaris recovered from spoiling cod fish (Gadus morhua). The molecular weight and isoelectric point of the enzyme were 120,000 +/- 2,000 and pH 6.8. The Michaelis constant for inosine as substrate was 3.9 x 10(-5). Guanosine also served as a substrate (Km = 2.9 x 10(-5). However, the enzyme was incapable of phosphorylizing adenosine. Adenosine proved to be useful as a competitive inhibitor and was used as a ligand for affinity chromatography of purine nucleoside phosphorylase following initial purification steps of gel filtration and ion-exchange chromatography.

Staple Trades, Subsistence Agriculture, and Nineteenth-Century Cape Breton Island

Abstract In the territory that eventually became Canada, the early pattern of European settlement and economic development was largely shaped by staple trades and subsistence agriculture. Staple trades were heavily dependent upon foreign capital, technology, labor, and markets; subsistence farming rested upon European settlers, the family farm, and local markets. These two ingredients of the early pattern of Canada were found on Cape Breton Island in the nineteenth century. Cod fishing, coal mining, and mainly subsistence farming created much of the Island's settlement, economy, and society. Each of these economies occupied relatively discrete areas, forming a mosaic of different ways of life and work on the Island. Woven through this pattern was a demographic cycle of primarily Scottish immigration, population growth, and emigration. These elements created a highly complex pattern, a regional human geography that is suggestive of other parts of nineteenth-century Canada.

Cod liver oil does not reduce ventricular extrasystoles after myocardial infarction

Previous work has shown that in experimental animal models a lower incidence of arrhythmias and sudden death was observed if the animals were fed cod liver oil or fish oil. After a 48-h control period starting, on average, 8 days after the onset of symptoms, 18 men who were recovering from acute myocardial infarction were given 20 ml d-1 cod liver oil for 6 weeks, either immediately after the control period, weeks 0-6 (n = 10), or during weeks 6-12 (n = 8). Forty-eight-hour Holter monitoring was carried out before cod liver oil administration and at the end of weeks 6 and 12. The eicosapentaenoic acid content of plasma phospholipids was increased by 230% during cod liver oil administration. However, no significant change was observed in the 24-h prevalence of ventricular extrasystoles or other arrhythmias during the study period. The mean ln number of ventricular extrasystoles was 2.95 +/- 0.51 (+/- SEM) during cod liver oil ingestion and 2.63 +/- 0.30 when not taking cod liver oil.

PREPARATION of FERMENTED SAUSAGES FROM UNDERUTILIZED FISH and MEAT SOURCES

Poultry, beef and pork meats were used in 1:1 combinations with mechanically deboned haddock or cod fish to produce narrow caliber sausages based on lactic acid fermentation at temperatures between 20° and 23°C. After fermentation the pH's of the fish-meats sausage combinations were reduced, ranging from 5.4 to 5.1 while the beef-pork sausage pH's fell from 5.1 to 5.0. Following drying for one week, the fish-meat sausages contained between 17 to 36% moisture while the beef-pork contained between 25 and 30% moisture. the initial fat content of all the sausages had been adjusted to 17% but following drying, the fish-meat sausages contained between 21 and 35% fat while the beef-pork sausage fat content was between 29 and 30%. The fish-meat sausages were found acceptable by taste panels consisting of between 25 and 70 panelists. However, the beef-pork sausages were preferred over the fish-meat combinations. A minority of panelists commented on the presence of a fish taste in the fish-meat combinations especially in the fish-chicken sausages.

Developmental Changes of C-Series Polysialogangliosides in Chick Brains Revealed by Mouse Monoclonal Antibodies M6704 and M7103 with Different Epitope Specificities1

We have established many mouse monoclonal antibodies detecting developmentally regulated antigens in chicken embryonic neural tissues of the otic vesicles and neural tube by immunizing mice with the membrane fraction of the neural tube and somite prepared from 3-d chick embryos. Among them, three monoclonal antibodies (MAbs) M6703, M6704, and M7103 were shown to react with the gangliosides isolated from chicken embryonic brains. The precise specificity of the antibodies was determined mainly by enzyme-immunostaining on thin layer plates. MAbs M6703 and M6704 bound to C-series polysialogangliosides including GT3, GT2, GT1c, GQ1c, and GP1c isolated from cod fish brains, but never to A-series, B-series, or X-series gangliosides. On the other hand, MAb M7103 antibody has a rather narrow specificity, reacting with GT1c, GQ1c, and GP1c, but not with ganglioside GT3. This indicates that the epitopes defined by these two MAbs are not with ganglioside GT3. This indicates that the epitopes defined by these two MAbs are different from each other. MAbs M6703 and M6704 recognize a trisialosyl residue, NeuAc alpha 2-8NeuAc alpha 2-8NeuAc alpha 2-3, while M7103 requires both a trisialosyl residue and the gangliotetraosy backbone structure for binding. As compared to similar MAbs which have been reported in the literature. M6703 and M6704 are unique in that they react equally with all of the C-series gangliosides and belong to the IgG3 subclass.(ABSTRACT TRUNCATED AT 250 WORDS)

Mutagenic and carcinogenic heterocyclic amines in Chinese cooked foods

Samples of 7 foods commonly eaten in the Northeast of China (i.e. fried and broiled fishes and broiled meat) were tested for mutagenicity on Salmonella typhimurium TA98 with S9 mix. The basic fractions of the samples were mutagenic, inducing 33–2930 revertants/g of cooked food. Fried walleye pollack (a kind of cod fish heated on a stainless steel pan) showed the highest mutagenicity, so attempts were made to isolate mutagens from the basic fraction of this food. The mutagens were purified by treatment with blue cotton and HPLC on a semi-preparative ODS column and analytical cation exchange and ODS columns. 5 mutagens were isolated and identified as 2-amino-3-methylimidazo[4,5- f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5- f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5- f]quinoxaline (MeIQ), 2-amino-3,4,8-trimethylimidazo[4,5,- f]quinoxaline (4,8-DiMeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP). 1 g of fried fish was estimated to contain 0.16 ng of IQ, 0.03 ng of MeIQ, 6.44 ng of MeIQx, 0.10 ng of 4,8-DiMeIQx and 69.2 ng of PhIP. MeIQx and PhIP accounted for 24% and 4.7%, respectively, of the total mutagenicity. The other 3 heterocyclic amines were each responsible for only 0.3–1.2% of the total mutagenicity.

Un litige franco-canadien actuel : la zone économique des 200 milles à Saint-Pierre-et-Miquelon

France-Canada current dispute : The 200 miles Exclusive Economie Zone in Saint-Pierre and Miquelon. Located on Gulf of St Lawrence entering, St Pierre and Miquelon Islands form the last French territory in North America. Traditional economic activities as cod fishing are deeply declining. The current chief question is one of 200 nautical miles, that involves a difference from analysis with Canada. The new Law of the Sea produces a new maritime problematic for Saint-Pierre and Miquelon because it's difficult to delineate a functional EEC within the context of a strong competition concerning cod fishing and offshore oil. Upon these two areas, Canada took an uncompromising political position.

Free amino acids as energy substrate in developing eggs and larvae of the cod Gadus morhua

The content of free amino acids (FAA) in the cod (Gadus morhua L.) egg is about 200 nmol at spawning, decreasing by about 100 nmol/egg during the egg stage and about 75 nmol/larva during the yolksac larval stage. Together, alanine, leucine, serine, isoleucine, lysine, and valine account for about 75% of the decrease. Ammonium accumulates gradually during the egg stage and is quickly excreted after hatching. The body protein content is maintained during the egg and yolksac larval stages. The measured oxygen uptake of the cod embryo during the egg and yolksac larval stages accounts for about 85% of the oxygen necessary to catabolize the FAA disappearing during this period. Ammonia excretion of the cod embryo, as taken from literature data, is similar to the expected ammonia production from catabolism of the FAA. Our data suggest that FAA are a major substrate for aerobic energy production in cod eggs and yolksac larvae. The implication of this finding for the production of a favourable first-feed for cod and other cultivated marine fish larvae, and for the selection of high quality eggs of marine fishes, is stressed.

Immunochemical analysis of cod fish allergen M: locations of the immunoglobulin binding sites as demonstrated by the native and synthetic peptides.

The major allergen of codfish (Allergen M) is a muscle protein belonging to the family of calcium binding parvalbumins. The primary structure of the molecule was established and the molecular weight was estimated from the sequence data to be 12,328. Allergen M consists of 113 amino acid residues and one residue of glucose. A molecular arrangement of three domains (AB, CD and EF--the latter two bind one Ca2+ ion each) was described for Allergen M, analogous to carp parvalbumin pI 4.25. The suggested structure was based on the extensive intramolecular amino acid homologies and the immunochemical cross-reactivities of the intact molecule and the two major isolated fragments. The immunological structure of Allergen M was studied by: 1. Modification of certain amino acids residues and study of the reactivity of the modified derivatives. 2. Examination of the immunochemical reactivity of a large number of overlapping peptides obtained by limited and selective tryptic hydrolyses. 3. Solid phase peptide synthesis (SPPS) of segments selected in regard to the reactivity of pre-examined native peptides. The immunological reactivity of the derivatives of Allergen M was assigned by: 1. Rocket line immunoelectrophoresis and quantitative precipitation using rabbit anti-Allergen M in precipitating antibody-mediated reactions and, 2. RAST/RAST-inhibition and PK test/PK-test inhibition using sera from individuals allergic to codfish in IgE-mediated reactions. The modification of Tyr-30 and Arg-75 in isolated and purified peptides indicated that the former was part of a reactive site whereas the latter did not contribute to the activity. Masking of Arg-residue or unchelating the two calcium ions from the native Allergen M, with the resulting perturbation of the tertiary structure, decreased the allergenicity by approximately 25%. Two major fragments of Allergen M were produced and purified: TM1 (residues 1-75) comprising domains AB and CD, and TM2 (residues 76-113) covering domain EF. Both were immunologically reactive; TM1 showing intermediate reactivity between Allergen M and TM2. A high degree of immunological cross reactivity was evident between TM1 and TM2. The finding was in concert with the high intramolecular amino acid homologies of Allergen M, and suggested that the reactive sites were repetitively distributed along the polypeptide chain. The immunological reactivity of several long-sequence overlapping peptides obtained by limited and selective trypsin hydrolysis of Allergen M was studied. The immunologically reactive sites were accordingly assigned to the following regions of the chain: 1. Residues 33-44 on the junction between the AB and CD domains.(ABSTRACT TRUNCATED AT 400 WORDS)

Gadusol, an enolic derivative of cyclohexane-1,3-dione present in the roes of cod and other marine fish. Isolation, properties and occurrence compared with ascorbic acid.

Gadusol, C8H12O6, has been isolated from roes of the cod (Gadus morhua L.), i.e., ovaries that contain ripe eggs just before spawning. The concentration is about 4 g/kg dry wt. It has been identified as 1,4,5-trihydroxy-5-hydroxymethyl-2-methoxycyclo-hex-1-en-3-one and this structure was confirmed by synthesis of the anhydro tetra-acetate derivative from methyl 3,5-diacetoxy-4-methoxybenzoate. Concentrations of gadusol in the roes of other marine teleost fish examined are of the same order as in cod roes. Gadusol has some properties similar to ascorbic acid and both compounds, after oxidation, react with 2,4-dinitrophenylhydrazine in the commonly-used assay procedure for ascorbic acid. Specific assays showed that the concentrations of gadusol in the roes of marine fish are severalfold greater than those of ascorbic acid. Gadusol is structurally related to the mycosporines previously reported from a number of different organisms.

Gill O 2 consumption in a teleost fish, Gadus morhua

Stimulated by the many physiological functions of fish gills this study reports on perfusion studies of gilll arches and head preparations from the Atlantic cod, Gasud morhua, with the objective of determining the oxygen requirement of gill tissues in situ. An additional objective was to assess what fraction of the gill tissue O 2 consumption is taken up directly from ambient water without intervention of internal gill perfusion. At 15°C and air-saturated ambient water about 58% of the total gill O 2 requirement was taken up from the perfusate while 42% entered gill tissues directly from ambient water. In relation to total O 2 uptake of intact cod fish the gill tissue requires 6.65% giving gill tissues a weight-specific O 2 requirement of 95.2 μl O 2·g body wt −1 ·h −1 or nearly twice that of the intact fish (54.5 μl O 2·g body wt −1·h −1). It is discussed how the gill tissue O 2 requirement influences the employment of the Fick principle for calculations of cardiac output in fishes.

A new thin-layer chromatographic approach for separation of multisialogangliosides: Novel gangliosides fractions in the embryonic chicken brain

A novel thin-layer chromatographic procedure has been developed that permits rapid, high-resolution separation of complex ganglioside mixtures and direct densitometric quantification. A special advantage of the new procedure, performed by two different consecutive runs on high-performance thin-layer chromatography plates, is an excellent separation of multisialogangliosides containing more than three sialic acid residues. Using the new procedure, 10 unidentified fractions were detected in embryonic chick brains. These gangliosides were clearly distinguishable from the known gangliosides, GM1, GD3, GD1a, GD2, GD1b, GT1b, and GQ1b. Eight of these “additional” fractions were also found in the brains of rays. From published data on the cod fish brain, 6 of the novel fractions are suggested to correspond to GT3, GT2, GT1c, GQ1c, GP1c, and GP1b. Four fractions, moving on thin-layer chromatography plates below the suggested GP1c have not been reported previously in any vertebrate. Due to their very slow migration rates they may contain gangliosides with six, seven, or more sialic acid residues. During development of the chicken, the relative amounts of the newly detected fractions decrease in favor of GT1b and GD1a.

Gadusol, a metabolite from fish eggs

Gadusol, a metabolite from the eggs of cod and other fishes, has been identified as 1,4,5-trihydroxy-2-methoxy-5-hydroxymethylcyclohex-1-en-3-one, related to the mycosporines and analogous compounds.

Properties of phosphofructokinase and tolerance to hypoxia in vertebrate myocardia

1. 1. Kinetic properties of myocardial phosphofructokinase were compared in flounder and cod at 15°C and in an aquatic turtle and the rainbow trout at 25°C. The myocardia of flounder and turtle unlike those of the cod fish and trout maintain efficient contractility under hypoxia. 2. 2. Flounder PFK has a lower affinity for ATP and a higher affinity for fructose-6-phosphate than cod PFK. It is less inhibited by ATP and less stimulated by AMP. For turtle PFK in relation to trout PFK the reverse is true. 3. 3. The highest PFK activity was found between pH 7.8 and 8.0. For flounder it remained high down to pH 7.1, but was almost zero at 7.0. For cod and turtle the PFK were inactive at pH below 7.2. At pH 6.9 the activity of trout myocardial PFK was reduced about two-thirds of the maximum value. 4. 4. Thus, no consistent differences between PFK activity of hypoxia tolerant and hypoxia non-tolerant myocardia were observed.

Isolation and characterization of two isomers of brain tetrasialogangliosides.

Two isomers of tetrasialogangliosides were isolated and purified to homogeneity from human, bovine, chicken, and cod fish brains by employing DEAE-Sephadex and Iatrobeads column chromatographies. The tetrasialogangliosides of human, bovine, and chicken brains appeared to be identical because they had identical mobilities on thin layer plates developed with six different solvent systems. The tetrasialoganglioside of cod fish brain moved slower on thin layer plates than the tetrasialoganglioside from the other species. The ganglioside preparations were subjected to mild acid hydrolysis, neuraminidase treatment, and periodate oxidation followed by borohydride reduction. The structures of the two isomers were differentiated from each other by controlled mild acid hydrolysis in both aqueous and organic solvents. The structure IV3(NeuAc)2,II3(NeuAc)2-GgOse4ceramide is assigned to the tetrasialoganglioside of human, bovine, and chicken brains; and the structure IV3NeuAc,II2(NeuAc)3-GgOse4ceramide is assigned to that of cod fish brain. The possible pathways for the synthesis of the two tetrasialogangliosides are discussed.

Bestimmung eines niedrigen Nitrit-Niveaus ohne vorherige Extraktion

A method has been devised for the determination of nitrite at low level that is directly applicable to food or other dried matrices without prior extraction. Nitric oxide released from nitrite through the action of acetic acid is determined using a chemiluminescence analyser. The limit of detection is approximately 0.02 microgram, the coefficients of variation being 5.7 and 8.2% using 0.1 and 0.05 microgram of sodium nitrite, respectively. The chemiluminescence analyser response is diminished when water in excess of 0.5 ml is present in the assay system unless hydrogen bromide in acetic acid is used instead of acetic acid alone. The application of the method to the direct determination of nitrite in freeze-dried cod fish has indicated a content of 0.25 mg NaNO2 per kg, equivalent to 0.050 mg per kg of the original undried material.

Public Health Aspects of "Codworm" Infection: A Review

Larvae of the nematode Phocanema decipiens (Ascaridida: Anisakidae), known as "codworm" in the vernacular, occur in the musculature of some cod and other marine fishes in both hemispheres, particularly in the temperate and polar climatic zones. The natural definitive hosts are Pinnipedia (seals, sea lions, walruses). For many years regarded incapable of surviving in man, recent reports from Japan indicate that in certain circumstances codworm larvae may temporarily invade the human gastric mucosa, producing clinical symptoms. Several nonclinical cases, in which the larval worms were expelled orally or in the feces of humans, have been reported from Canada (1), the USA (5), Greenland (1), and the U.K. (1). The source of human infections was raw, lightly marinated, or insufficiently cooked sea fish. The ability of codworm larvae to penetrate the stomach wall of other mammals has been demonstrated experimentally in rabbits, rats, dogs, and pigs. Natural infection of a dog in Hokkaido has been reported. For the human cases, information on age and sex of patients, specific source of infection, symptoms, and gross pathology are reviewed. The name applied to human infections and their diagnosis, treatment, prognosis, prevention, and public health implications are discussed. Cooking at 70 °C for 7 min or 60 °C for 10 min and freezing at −20 °C for 24 h are lethal to codworm larvae in fish flesh, thus providing reliable methods for preventing human infections. Some comparisons are made with larval Anisakis infections in man and future research needs, particularly in relation to the public health question, are discussed.

Serine and threonine ethanolamine phosphate diesters, and some other unusual compounds in the lens of the cod fish ( Gadus morhua) and haddock ( Gadus aeglefinus)

The lens of the cod ( Gadus morhua) and haddock ( Gadus aeglefinus) contains compounds absent from the mammalian lens. We have detected the presence of serine ethanolamine phosphate diester and threonine ethanolamine phosphate diester. We have also found that free histidine occurs in these fish lenses at more than ten times its concentration in the rabbit lens, and that the concentration of total free amino acids is about three times that in the rabbit lens. Some large cod lenses contained riboflavin. We have confirmed the presence of N-acetylhistidine (Anastasi, Correale and Erspamer, 1964) and of an unknown compound absorbing at 360 nm (Kennedy and Milkman, 1956).