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At least 19 recordsLinked to original sources
PubMed1992

Dietary protein levels affect growth and protein metabolism in trunk muscle of cod, Gadus morhua.

Cod (Gadus morhua) of 50 g body weight were kept at 14 degrees C. The fish were fed ad libitum during 80 days a diet containing protein levels which in terms of total energy corresponded to 25%, 45% or 65%. Growth increased in accordance with protein-energy levels. The protein content per gram of wet weight of white trunk muscle was unchanged, as was the myofibrillar protein myosin heavy chain determined by the antigen-antibody reaction of the enzyme-linked immunosorbent assay. The amount of messenger ribonucleic acid (mRNA) coding for myosin heavy chain was lower at 25% than at 45% or 65% protein-energy intake, the differences being significant per gram of wet weight of muscle. Acid proteinase activity was highest at the lowest protein-energy intake. Glycogen content in muscle increased with the protein-energy levels. It is concluded that the metabolic response of white trunk muscle to graded protein-energy intake included a change in the capacity to synthesize myosin heavy chain as judged by its mRNA content. The protein content per gram of wet weight was unaffected by dietary protein-energy levels of 25%, 45% and 65%, but protein accretion and thus growth of the animals increased with the protein intake. Dietary protein-energy restriction caused a rise in acid proteinase activity and a decrease in content of mRNA for myosin heavy chain, resulting in a diminished growth rate at an unchanged protein content per gram of wet weight of muscle.

Animals↗
PubMed1984

The influence of the ratio of protein energy to total energy in the feed on the activity of protein synthesis in vitro, the level of ribosomal RNA and the RNA-DNA ratio in white trunk muscle of Atlantic cod (Gadus morhua).

Cod (Gadus morhua) were fed diets containing protein energy to total energy levels (PE/TE) of 10.0, 20.6, 29.6, 38.4, 56.2 and 74.1% for 21 days. Ribosomes were isolated from the white trunk muscle tissue, the capacity for protein synthesis in vitro determined and related to muscle tissue wet weight rRNA and DNA. Protein concentrations of less than 47.4% PE/TE in the diets reduce the ribosomal capacity for protein synthesis per g wet weight and per mg DNA, and the tissue contents of rRNA and ratio of rRNA/DNA. The capacity for muscle protein synthesis in vitro is a significant and sensitive parameter of protein inadequacy in fish diets.

Animals↗
PubMed1996

Nucleotide sequence of transferrin cDNAs and tissue-specific of the transferrin gene in Atlantic cod (Gadus morhua).

Atlantic cod (Gadus morhua) transferrin cDNAs were isolated from a liver cDNA library using a cod transferrin-derived polymerase chain reaction product as a hybridization probe. The composite nucleotide sequence of two overlapping clones was 2223 bp in length excluding the poly(A) sequence and was equivalent to 87% of the 3' end of the Atlantic salmon transferrin cDNA sequence. Comparison of the deduced amino acid sequence of cod, salmon, Xenopus and several mammalian transferrins revealed that the two fish sequences are more similar with respect to their amino acid sequence and the position of additions/deletions than to other vertebrate transferrins. Conservation of the iron-binding domains and cysteine residues involved in disulphide bridges indicates that all transferrins share similar tertiary structure and support the hypothesis that extant vertebrate transferrin genes were derived from a gene duplication before the divergence of fish, frogs and mammals. Cod transferrin mRNA was detected in both brain and liver RNA and to a much lesser extent in RNA isolated from kidney and heart in contrast to salmon and several other vertebrates in which the transferrin gene is not expressed in brain.

Amino Acid Sequence↗
PubMed2003

Metabolic priorities during starvation: enzyme sparing in liver and white muscle of Atlantic cod, Gadus morhua L.

Atlantic cod, Gadus morhua, respond to starvation first by mobilising hepatic lipids, then muscle and hepatic glycogen and finally muscle proteins. The dual role of proteins as functional elements and energetic reserves should lead to a temporal hierarchy of mobilisation where the nature of a function dictates its conservation during starvation. We examined (1) whether lysosomal and anti-oxidant enzymes in liver and white muscle are spared during prolonged starvation, (2) whether the responses of these enzymes in muscle vary longitudinally. Hepatic contents of lysosomal proteases decreased with starvation, whereas those of catalase (CAT) increased and lysosomal enzymes of carbohydrate metabolism and glutathione S-transferase (GST) did not change. In white muscle, starvation decreased the specific activity of lysosomal enzymes of carbohydrate degradation and doubled that of cathepsin D (CaD). The activity of anti-oxidant enzymes and acid phosphatase in muscle was unchanged with starvation. In white muscle neither lysosomal enzymes nor anti-oxidant enzymes varied significantly with sampling position. In cod muscle, antioxidant enzymes, CaD and acid phosphatase are spared during a period of starvation that decreases lysosomal enzymes of carbohydrate metabolism and decreases glycolytic enzyme activities. In cod liver, the anti-oxidant enzymes, CAT and GST, were also spared during starvation.

Animals↗
PubMed1985

[Brain of the cod (Gadus morhua morhua, Linné 1758) (Pisces, Paracanthopterygii). Qualitative and quantitative analysis of major subdivisions].

The Cod, Gadus morhua, is a North Atlantic fish of the family Gadidae which occurs at depths of 80 to 600 m (usually 150 to 200 m). It often occurs in shoals and tends to be migratory. It has a typical teleost brain except for the gadid feature of long olfactory tracts. Gadid fishes have a low level of encephalization (RIDET, 1982). The index of encephalization of the Cod is near the mean for the family. This index changes with season due to the change in body weight; it is lowest during the spawning season (which takes place in spring). Five subspecies of Gadus morhua are recognized. A comparison was made of the index of encephalization of the subspecies which is restricted to the White Sea, Gadus morhua maris albi, Derjugin 1920 and Gadus m. morhua, Linné 1758. The index of the White Sea form was significantly higher, thus supporting its recognition as subspecies. A volumetric analysis was made of the subdivisions of the Cod brain. It was found to have a large cerebellum, large medulla oblongata and a tendency to macrosmy, but a small telencephalon and tectum opticum (tendency to micropty). This is what would be expected from the environment and habits of this fish.

Animals↗
PubMed1993

Calpain processing of brain microtubules from the Atlantic cod, Gadus morhua.

Microtubules isolated from Atlantic cod (Gadus morhua) brains retained assembly competence and ultraculture, although treatment with rabbit calpain resulted in loss of MAPs. In addition, spirals and aberrant structures formed when calpain I was activated post assembly. No such effect was seen with calpain II. Soluble fractions from cod brain were found to contain proteolytic activity that could be blocked by exogenously added calpastatin. Calpain was also isolated from cod muscle tissue with 10 times less yield, compared to rabbit lung. On the basis of Ca(2+)-requirements for activation in the mM range, electrophoretic mobility, antigenicity and hydrophobicity, we conclude that the proteolytic activity was attributable to calpain II. There was no difference in effects of rabbit and cod calpain II on cod microtubule proteins, indicating that calpain is a conserved protein. Our results suggest that calpains might be involved in the Ca(2+)-dependent irreversible regulation of cod brain microtubules.

Animals↗
PubMed1998

Cardiac output as a predictor of metabolic rate in cod gadus morhua

Adult Atlantic cod (2 kg Gadus morhua) were fitted with Doppler ultrasonic flow-probes to measure ventral aortic outflow (i.e. cardiac output). The probes remained patent for upwards of 3 months, during which time detailed relationships between cardiac output (), heart rate (fh) and rate of oxygen consumption (O2) were determined as a function of swimming speed and temperature (5 degreesC and 10 degreesC). The rate of oxygen consumption increased linearly with and exponentially with swimming speed. A very good correlation was observed between O2 and (r2=0.86) compared with the correlation between O2 and fh (r2=0.50 for all 10 degreesC data and r2=0.86 for all 5 degreesC data). However, the O2 versus fh correlation gradually improved over approximately 1 week after surgery (r2=0.86). The relationship between O2 and was independent of temperature, while the relationship between O2 and fh changed with temperature. Hence, calculating O2 from is simpler and does not require that temperature be recorded simultaneously. Variations in cardiac output were determined more by changes in stroke volume (Vs) than by fh; therefore, fh was a less reliable predictor of metabolic rate than was . Given that can be used to estimate O2 so faithfully, the advent of a cardiac output telemeter would enable robust estimates to be made of the activity metabolism of free-ranging fish in nature, thereby strengthening one of the weakest links in the bioenergetic models of fisheries biology.

Journal Article↗
PubMed1992

Eggshell zona radiata-proteins from cod (Gadus morhua): extra-ovarian origin and induction by estradiol-17 beta.

Using Atlantic cod (Gadus morhua) as a model organism, the aim of this report was to delineate whether teleostean eggshell zona radiata proteins have their origin, i.e., site of synthesis, in gonadal or somatic tissues. Estradiol-17 beta was administered intraperitoneally to one-year-old cod (Gadus morhua) with either undeveloped gonads or with differentiated gonads. By immunoblotting procedures estradiol-dependent protein induction was investigated using specific rabbit antisera directed against cod eggshell proteins and brown trout vitellogenin. No immunological cross-reactions were observed between the two antisera, and eggshell proteins and vitellogenin were detected in blood plasma and somatic tissues only in estradiol-treated cod. Three plasma-components were immunoreactive to antiserum directed against eggshell proteins, and these proteins possessed molecular weights of 78, 54 and 47 kDa, identical to the molecular weights of the cod eggshell alpha, beta and gamma zona radiata-proteins. These three immunoreactive plasma-components were observed after administration of estradiol-17 beta to both sexes, also in males having reached spermiation, and in juveniles of either sex without developed gonads. The data are interpreted to signify that cod eggshell zona radiata-proteins originate in an extra-ovarian tissue and are transported in the blood for deposition in the ovaries. We propose that oogenesis involves estradiol-17 beta regulation of both eggshell zona radiata-proteins and vitellogenin synthesis.

Animals↗
PubMed2006

Reversible inactivation of alkaline phosphatase from Atlantic cod (Gadus morhua) in urea.

Alkaline phosphatase (AP) from Atlantic cod (Gadus morhua) is a zinc and magnesium containing homodimer that requires the oligomeric state for activity. Its kinetic properties are indicative of cold-adaptation. Here, the effect of urea on the structural stability was studied in order to correlate the activity with metal content, the microenvironment around tryptophan residues, and events at the subunit interface. At the lowest concentrations of urea, the first detected alteration in properties was an increase in the activity of the enzyme. This was followed by inactivation, and the release of half of the zinc content when the amount of urea reached levels of 2 M. Intrinsic tryptophan fluorescence and circular dichroism ellipticity changed in the range 2.5 to 8 M urea, signaling dimer dissociation, followed by one major monomer unfolding transition at 6-8 M urea as indicated by ANS fluorescence and KI fluorescence quenching. Gibbs free energy was estimated by the linear extrapolation method using a three-state model as 8.6 kcal/mol for dimer stability and 11.6 kcal/mol for monomer unfolding giving a total of 31.8 kcal/mol. Dimer association had a very small ionic contribution. Dimers were stable in relatively high concentration of urea, whereas the immediate vicinity around the active site was vulnerable to low concentrations of urea. Thus, inactivation did not coincide with dimer dissociation, suggesting that the active site is the most dynamic part of the molecule and closest related to cold-adaptation of its enzymatic activity.

Alkaline Phosphatase↗
PubMed2001

Immune parameters of immunised cod (Gadus morhua L.).

The immune response of cod (Gadus morhua L.) is unusual in that specific antibody response is limited or absent. In the present study cod was immunised with haptenated and non-haptenated protein antigen at two different temperatures and the antibody response monitored over a period of 18 months. Other humoral parameters of immunological importance were also analysed, namely total immunoglobulin concentration, anti-protease and spontaneous haemolytic activity. No specific antibody response was detected but increased activity of non-specific anti-TNP antibodies was observed 10-12 weeks after immunisation, irrespective of the antigen used. This antibody activity was attributed to the adjuvant used (FCA) and did not cross react with other antigens tested. Other parameters were probably not influenced by the immunisation but seasonal fluctuations were indicated. The immunoglobulin level appeared to peak in August-September and the anti-protease activity and the haemolytic activity in October-January.

Animals↗
PubMed2003

Selection-induced variation at the pantophysin locus (PanI) in a Norwegian fjord population of cod (Gadus morhua L.).

A total of 1290 cod (Gadus morhua L.), sampled between 1985 and 1999 from a spawning area in the Trondheimsfjord, Norway, were assayed for the nuclear-encoded locus PanI (pantophysin). The majority of samples were taken during the spawning season at two nearby sampling locations at depths of 100 and 60 m, respectively. Genetic analysis revealed significant effects of cohort, sex and sampling location on allele frequencies at PanI. The contribution of each of these three factors to the total among-sample diversity (FST) of 8.01% at PanI was estimated to be 3.78, 2.55 and 1.68%, respectively. Sign tests revealed a significant excess of heterozygotes at both sampling locations in females; a significant excess of heterozygotes in males was observed at one of the localities. Mutation, genetic drift and immigration do not appear to contribute significantly to the observed genetic heterogeneity at PanI, leaving natural selection as the main explanatory factor for the Hardy-Weinberg imbalance. The dynamics of the selection at PanI appear to be complex. Analysis of age, sex and cohort proved crucial to disentangle putative explanatory factors from their secondary effects.

Animals↗
PubMed2002

Regime shift signatures from stable oxygen isotopic records of otoliths of Atlantic cod (Gadus morhua).

The sudden collapse of Atlantic cod (Gadus morhua) may relate to ocean climate, or regime shifts as demonstrated in production of Pacific salmon. This paper reports the results of stable oxygen isotope ratio analyses (18O/16O or delta18OA) from 91 otoliths of cod over a period of about 20 years. Seasonal delta18OA variations of individual otoliths started at an initial value of about -0.5 to 0 per thousand VPDB, and then reached a stable level in the range of +2.5 to +3.5 per thousand VPDB after 4-5 years. The initial low values correspond to the natal sources of mature cod, while the higher delta18OA values represent the water conditions before the cod was caught. This pattern of delta18OA variation was observed over the life history of all cod examined. Furthermore, the calculated isotopic temperatures agreed with those obtained from summer bottom trawl survey, indicating that delta18OA of otoliths could be used as a thermometer in determining the ambient seawater temperature where the cod lived. Comparison of long-term delta18OA records and biological and meteorological observations suggested that decadal-scale ecosystem changes did occur in the late 1970s and early 1990s in Atlantic Canada, comparable to regime shifts occurred in the North Pacific.

Animals↗
PubMed1995

Physiology and behaviour of free-swimming Atlantic cod (Gadus morhua) facing fluctuating temperature conditions

Atlantic cod (Gadus morhua L.), acclimated to 5 °C, were equipped with ultrasonic transmitters which allowed the continuous monitoring of their vertical movements and heart rate. Fish were then placed in a 125 m3 tower tank in which the various thermal conditions they encounter in their natural environment were reproduced. Physiological and behavioural responses of cod were followed in parallel to the induced environmental changes. The experimental conditions studied in the tower tank were also reproduced in a swimming respirometer, where oxygen consumption and heart rate could be monitored within the activity range of a free-swimming animal. In a homogeneous water column, a rise in temperature induced marked increases in fish swimming activity, heart rate and heart beat-to-beat variability. In a thermally stratified environment, voluntary activity also increased when the thermal structure of the water column was altered, though no temperature-dependent changes in heart rate were observed. In this case, fish avoided the new temperature conditions, exhibiting distinct thermoregulatory behaviour. Stratification of the water column also prompted daily cyclic changes in fish distribution, animals tending to be in deeper and colder water layers during the day and in shallower and warmer layers at night. Respirometry experiments revealed that the thermoregulatory behaviour observed in free-ranging fish was probably driven by the energetic expedient of maintaining the physiological status quo ­ i.e. avoiding bioenergically costly reacclimation processes. Indeed, acute temperature increases or decreases of 2.5 °C led to marked differences in oxygen consumption, with metabolic rate changes of 15 and 30 %, respectively. The persistent linear relationship between heart rate and oxygen consumption allowed us to estimate, from the heart rate recorded in free-swimming fish, the entire range of metabolic responses that cod underwent voluntarily while experiencing a thermally stratified water column. The most profound metabolic effect, however, was observed with feeding, when oxygen consumption increased by as much as 80 %, resulting in an estimated 90 % reduction in their subsequent scope for activity.

Journal Article↗
PubMed2006

Francisella sp. (Family Francisellaceae) causing mortality in Norwegian cod (Gadus morhua) farming.

In 2004, a new disease was detected in cod (Gadus morhua) in western Norway. Affected cod had white granulomas in the visceral organs and skin. A species of Francisella was isolated on blood agar plates from moribund cod. The bacterium could be grown at temperatures ranging from 6 to 22 degrees C, but did not grow at 37 degrees C. Challenge experiments showed that Francisella sp. was the cause for the new disease. The 16S rDNA gene sequence from Francisella sp. showed 99.17% similarity to F. philomiragia, and the 16S-23S ribosomal RNA intergenic spacer (249 nt), shows a similarity with that from Francisella isolated from tilapia and F. tularensis of 96.8 and 35.9%, respectively. The 23S sequence is more similar to F. tularensis, 97.7% (2,862 nt), compared to the tilapia isolate 96.8% (2,131 nt). The partial putative outer membrane protein (FopA) sequence (781 nt) from Francisella sp. shows a similarity with that from F. tularensis and F. philomiragia of 77.3 and 98.2%, respectively. Based on sequence data, culturing temperatures and pathogenicity for cod, it is suggested that this Francisella sp. from cod could be a new species of Francisella, Family Francisellaceae.

Animals↗
PubMed2004

Enhanced protein synthetic capacity in Atlantic cod (Gadus morhua) is associated with temperature-induced compensatory growth.

Atlantic cod (Gadus morhua) were held either at seasonal ambient temperatures (-0.3 to 11 degrees C) or at a relatively constant control temperature (8-11 degrees C) to investigate aspects of protein synthesis during a period of compensatory growth. Protein synthesis rate, total RNA, and RNA-specific protein synthesis rate were determined in white muscle and liver when ambient temperatures were -0.3, 4.5, and 11 degrees C in February, June, and July, respectively. To allow for comparisons between treatment temperatures, fish were also acutely transferred to a comparable assay temperature in February and June. Over the transition from 4.5 to 11 degrees C (June to July), the ambient-held cod had a significant increase in size and a substantially higher growth rate relative to control-held fish over the same period, consistent with cold-induced compensatory growth. During the onset of this enhanced growth, in June when ambient temperature was approximately 4.5 degrees C, ambient-held fish elevated their capacity for protein synthesis in the white muscle and liver via elevation of the RNA content. When ambient temperature reached the same point as for the control fish (11 degrees C), the rate of white muscle protein synthesis remained higher in the ambient-held vs. that in the control-held fish, a process facilitated by elevated RNA content and greater RNA-specific rate of protein synthesis. In the liver, all measured characteristics of protein synthesis were the same for ambient and control fish in July. The latter suggests that compensatory growth may be in part explained by improved efficiency of protein synthesis.

Adaptation, Physiological↗
PubMed2004

Stages of embryonic development in the Atlantic cod Gadus morhua.

The early development of the Atlantic cod, Gadus morhua was studied from fertilization until first-feeding. Multiple families were reared at 7 degrees C and a developmental staging series was prepared using morphological landmarks visible with the light microscope. Stages were named rather than numbered to allow for future additions and broadly grouped into larger time intervals called periods. The most useful staging features were found to be initially cell number, and later in development, somite number. The mean cell cycle time for the first six cleavages was 135 min and the linear regression equation for development of somites(s) over time (t) was s = 0.29t - 18.14. The segmentation period began at 220 h postfertilization (hpf), and unlike some other teleosts, the addition of new somites continued throughout the majority of embryonic development, until just prior to hatching. Hatching occurred at 256 hpf, after which individuals remained motionless at the water's surface, undergoing negative phototaxis only after the first day posthatch. The first-feeding stage was reached at the end of the third day posthatch, subsequent to development of a functional jaw and hindgut. This staging series provides an essential baseline reference for future experiments involving developing cod embryos and for the aquaculture industry.

Animals↗
PubMed1990

Purification and characterization of pancreatic elastase from Atlantic cod (Gadus morhua).

1. A pancreatic elastase from Atlantic cod (Gadus morhua) has been purified and characterized. 2. The enzyme is a very basic protein with an approximate mol. wt of 28,000. 3. The cod elastase has higher elastin specificity than porcine elastase, and it is inhibited by soybean trypsin inhibitor, which has no effect on porcine elastase. 4. The cod elastase expresses a higher turnover number (kcat) and catalytic efficiency (kcat/Km) than porcine elastase, but it is less thermostable.

Amino Acids↗