摘要:

Extraction of cod muscle with 0.3 Nperchloric acid followed by digestion of the residue in potassium hydroxide yielded an average of 16% more total glycogen than did classical digestion with 30% KOH. However, the differences tended to be less at higher glycogen levels. It was suggested that glycogen may be partially degraded during digestion with KOH, although no glycogenosis occurred during contact with alkali prior to heating. The proportion of residual glycogen not extracted by acid varied from 23% in unfrozen muscle to about 40% in liquid nitrogen-frozen and in slowly frozen muscle.Significant degradation of glycogen and high energy phosphorus compounds in frozen prerigor cod muscle was avoided by weighing samples in insulated beakers chilled by liquid nitrogen to prevent warming or thawing, and by homogenizing immediately on addition of acid extractant. Extraction with acid enabled the simultaneous determination of glycogen and phosphorus compounds on the same sample. Special sampling procedures were employed to reduce the sampling error due to variation in glycogen distribution along the fillet.

ISSN:0706-652X    

DOI:10.1139/f68-138

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Degradation of glycogen and starch in excised fish muscle blocks at 0–5 C postmortem was investigated by use of radioactive substrates. Separation of the various metabolites in the stored muscles was accomplished by perchloric acid extraction, gel filtration, treatment with anion and cation exchange resins followed by appropriate elution methods, and paper chromatography. The results showed that glycogen is degraded by both hydrolytic (anxiolytic) and phosphorolytic (Embden–Myerhof) pathways, and that starch is similarly degraded but more slowly. The degradative pattern was not significantly altered by brief blending of the muscle. Though lactate and glucose usually predominated, dextrins (or nondegraded substrate), maltose, glucose 6-phosphate, hexose diphosphate, ribose 5-phosphate, and ribose were also recovered. Though results obtained with muscle from widely different fish species were in general rather similar there were obvious quantitative differences which could possibly be attributed to a number of factors such as species differences, nutritional status, holding temperature, and state of maturation. The fact that labelled dextrins, glucose, and ribose were formed in muscle injected with radioactive lactate, suggested that all the reversible glycolytic enzymes and glycogen synthetase are functional in fish muscle blocks.

ISSN:0706-652X    

DOI:10.1139/f68-139

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The concentration of free fatty acids (FFA) in blood plasma of rainbow trout (Salmo gairdneri) maintained without food for 1–70 days averaged 424 (range 160–1003) μ equivalents FFA per liter plasma. The effect of starvation on the level of plasma FFA was limited, showing a more significant increase during the first 2 weeks without food than during prolonged periods of starvation. FFA in lateral line muscle averaged 147 (range 27–258) μ equivalents per 100 g wet tissue and during starvation a trend generally similar to that found for plasma FFA was observed. Starvation had no effect on the amounts of FFA in white dorsal muscle which averages 37 (range 13–73) μ equivalents per 100 g wet tissue. The results are discussed in relation to the mechanism of utilization of fat reserve in fish.

ISSN:0706-652X    

DOI:10.1139/f68-140

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The lipids of the pink jelly1fish (Cyanea capillata) have been isolated and separated by gel filtration into polar lipids, triglycerides, and a sterol. The fatty acid compositions were determined by gas–liquid chromatography, and are characterized by a high proportion of polyunsaturates. A special relationship involving arachidonic acid andC.capillatain the diet of the Atlantic leatherback turtle (Dermochelys coriacea coriacea) is proposed.

ISSN:0706-652X    

DOI:10.1139/f68-141

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Liver homogenates of bluegill,Lepomis macrochirusRafinesque, and channel catfish,Ictalurus punctatus(Walbaum), were shown by a manometric technique to contain soluble enzymes capable of degrading diisopropyl phosphorofluoridate (DFP) and 2,2-dichlorovinyl dimethyl phosphate (dichlorvos). Hydrolysis of the compounds was greatest in the presence of the manganic ion. Tentative identification of certain of the hydrolysis products suggested that cleavage of the anhydride bond was a degradation pathway for DFP and dichlorvos in vitro under the assay conditions employed. Substrate summation, inhibition, and activation experiments failed to clearly indicate more than a single enzyme hydrolyzing DFP and dichlorvos in the two fish.

ISSN:0706-652X    

DOI:10.1139/f68-142

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A latent form of malic enzyme activity (latent ME), which appears in the centrifuged tissue fluid of haddock skeletal muscle after the tissue has been frozen and thawed, appears also in the fluid of unfrozen haddock muscle after homogenization. It is more labile to refrigerated storage, ionizing radiation, and heat than is its normally soluble counterpart (free ME), and the two forms have demonstrably different electrophoretic migration rates. Although there is some evidence for catalytically active subunits for both forms, it has not yet been determined whether the latent activity is a true isoenzyme or a subunit of the free form.

ISSN:0706-652X    

DOI:10.1139/f68-143

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

In an experimental apparatus, elvers of the American eel (Anguilla rostrata) showed a stronger positive rheotaxis to fresh water than to salt water. The attractiveness of the fresh water was due to dissolved and particulate organic matter; these components were bio-degradable, heat stable, and nonvolatile. Four streams near Halifax, Nova Scotia, were tested, and were found to differ greatly in their attraction of elvers. Elvers were collected from each of three of these streams, and were not found to be attracted to their own stream water; elvers from one stream gave a greater rheotactic response than elvers from the other streams. The presence of adult eels in the water rendered it more attractive, whereas the presence of elvers made it less so.

ISSN:0706-652X    

DOI:10.1139/f68-144

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Twelve species of marine unicellular algae have been cultured under comparable conditions and the total fatty acids determined by gas–liquid chromatography. Some specific fatty acid relationships paralleling taxonomic groupings were detected but generally individual fatty acids within various algal classes showed large relative variations. The four Bacillariophyceae examined were notable for fatty acid compositions giving iodine values <150, whereas in eight other classes the iodine values were all approximately 200. It is suggested that 5,8,11,14,17-eicosapentaenoic acid, found to be a common algal longer-chain polyunsaturated fatty acid, is characteristically deposited in the lipids of filter-feeders ingesting unicellular algae.

ISSN:0706-652X    

DOI:10.1139/f68-145

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Experiments are reported on the effects of the insecticide Sevin and its hydrolytic product, 1-naphthol, on the survival, growth, and food consumption of larval and juvenile cockle clams (Clinocardium nuttalli). Clams were tested in standing sea water at a salinity of 25‰ and a temperature of 19 ± 2.0 C, and were fed cultures of the unicellular algaMonochryis lutheri. Algal cell concentrations ranged from 10,000 to 200,000 cells per ml of test solution. Toxicant concentrations ranged from 0.1 to 10.0 mg/liter.Larvae exposed to Sevin concentrations of 0.8 mg/liter were dead by day 7 of the test, and the growth of those exposed to 0.4 mg/liter was reduced by 15%. Sevin was less toxic than 1-naphthol to juvenile clams, the respective 96-hr TLm's (median tolerance limits) being 3.75 and 2.70 mg/liter. The growth of juvenile clams was reduced more by 1-naphthol than by Sevin. The food consumption of juvenile clams exposed to 1.6 mg/liter of Sevin was markedly reduced and their food conversion efficiency was impaired.Adult clams exposed to Sevin concentrated the toxicant in their tissues; maximum concentrations were reached after 12 hr of exposure. Clams exposed at 11 C concentrated more toxicant than those exposed at 20 C. Tissue concentrations of toxicant decreased sharply after the clams had been in clean sea water for 12 hr.

ISSN:0706-652X    

DOI:10.1139/f68-146

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Nine species of pelagic amphipods representing eight genera were collected from the drifting ice station Arlis II over the continental shelf and slope off northeast Greenland, from 77°29′N lat, 9°38′W long to 67°03′N lat, 26°18′W long.Parathemisto abyssorumpredominated in this area and in a similar area of the Beaufort Sea, but was less abundant in a high arctic area north of Greenland.Gammarus wilkitzkii,Apherusa glacialis,Pseudalibrotus nanseni, and probablyEusirus holmiiare associated with the underside of ice and their distribution is apparently independent of bottom depth.Gammarus wilkitzkii,A.glacialis,P.abyssorum, andP.libellulareproduce in the waters off northeast Greenland. The boreal speciesCyphocaris bouvieriis newly recorded from northeast Greenland waters. An ellobiopsid parasite,Thalassomyces marsupii, hinders the development of some primary and secondary sexual characteristics ofP.abyssorum.The zooplankton fauna off northeast Greenland is a continuation of the arctic fauna with a definite, but perhaps irregular, boreal influence and suggests that water under an ice cover may not always be arctic.

ISSN:0706-652X    

DOI:10.1139/f68-147

出版商:NRC Research Press    

年代:1968

数据来源: NRC