Polyphosphate Treatment of Frozen Cod. I. Protein Extractability and Lipid Hydrolysis

1964 ◽  
Vol 21 (1) ◽  
pp. 101-106 ◽  
Author(s):  
W. J. Dyer ◽  
H. Brockerhoff ◽  
R. J. Hoyle ◽  
D. I. Fraser
Keyword(s):  
Specific Effect ◽  
Lipid Hydrolysis ◽  
Ionic Concentrations ◽  
Extractable Protein ◽  
Protein Extractability

Tripolyphosphate dipped and undipped control paired cod fillets stored at −12 °C showed no differences occurring on storage in extractable protein, lipid hydrolysis, or thaw drip. A higher yield of frozen and of thawed fillets was obtained from the dipped samples due to water uptake.No specific effect of tripolyphosphate on thaw drip was obtained at the ionic concentrations used, but it is postulated that such effects might occur in the presence of about 1% salt.

Temperature and Deteriorative Changes in Postrigor Cod Muscle Stored up to 14 Days in the Superchill Range, −1 to −4 C

1975 ◽  
Vol 32 (9) ◽  
pp. 1595-1605 ◽  
Author(s):  
Sandra S. Nowlan ◽  
W. J. Dyer ◽  
R. A. Keith
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Deleterious Effect ◽  
Storage Life ◽  
Lipid Hydrolysis ◽  
Bacterial Action ◽  
Extractable Protein ◽  
Protein Extractability ◽  
Storage Temperatures

The effect of several storage temperatures in the superchill range (−1, −1.6, −2.3, −3, and −4 C) on bacterial and autolytic spoilage processes in postrigor cod muscle was assessed. Changes in trimethylamine, hypoxanthine, and pH, monitored as spoilage indicators, were slight during superchilling at all temperatures between −1 and −4 C for 3 and 6 days, and 14 days at −4, indicating inhibition of bacterial action. However, at −1.6 and at 0 C spoilage thresholds were reached in 10 and 6 days, respectively. Salt extractable protein remained unchanged, but mild lipid hydrolysis occurred at all temperatures.In samples superchilled for 3 or 6 days, then thawed and held at +5 or +10 C, spoilage processes resumed as judged by trimethylamine, hypoxanthine, and free fatty acid increases. Changes at +5 C in samples that had been held at −1 and at −1.6 were slightly slower than in controls at 0 C similarly treated, but in samples presuperchilled at −3 and −4 spoilage changes at +5 were markedly delayed. No deleterious effect on protein extractability was detected. Thus superchilling at −4 C for 3 and for 6 days was very effective, increasing the postfilleting storage life to 8 and 11 days, respectively, as compared to 5 days for controls held at 0 for 3 days before transfer to 5 C.

scholarly journals Aspartate aminotransferase. The effects of ionic concentration on kinetic constants of both isoenzymes

1968 ◽  
Vol 106 (3) ◽  
pp. 581-586 ◽  
Author(s):  
T. R. C. Boyde
Keyword(s):  
Aspartate Aminotransferase ◽  
Specific Effect ◽  
Ionic Concentration ◽  
Phosphate Concentration ◽  
Kinetic Constants ◽  
Sharp Minimum ◽  
Ionic Concentrations ◽  
Michaelis Constants ◽  
Added Salt

1. The Michaelis constants for both isoenzymes for both substrates depend strongly on ionic concentration, being approximately proportional to phosphate concentration over considerable ranges. This is probably an effect of anions only. 2. In the absence of added salt, Km (2-oxoglutarate) (anionic isoenzyme) is so small as to be indeterminate. 3. Km (l-aspartate) (anionic isoenzyme) passes through a sharp minimum at about 3·3mm-phosphate. It is not clear whether this is a specific effect of phosphate. 4. Both substrates are inhibitory at sufficiently low ionic concentrations. 5. A modified graphical procedure is described for the derivation of the kinetic constants.

Deteriorative Changes During Frozen Storage in Fillets and Minced Flesh of Silver Hake (Merluccius bilinearis) Processed from Round Fish Held in Ice and Refrigerated Sea Water

1976 ◽  
Vol 33 (11) ◽  
pp. 2560-2567 ◽  
Author(s):  
Doris Fraser Hiltz ◽  
Barbara Smith Lall ◽  
D. W. Lemon ◽  
W. J. Dyer
Keyword(s):  
Lipid Oxidation ◽  
Sea Water ◽  
Frozen Storage ◽  
Fat Content ◽  
Storage Life ◽  
High Fat ◽  
Lipid Hydrolysis ◽  
Extractable Protein ◽  
Silver Hake ◽  
Merluccius Bilinearis

During frozen storage at −10 C, deterioration in muscle of silver hake (Merluccius bilinearis) was marked by rapid and extensive production of dimethylamine, concomitant decrease in extractable protein, and by lipid hydrolysis. Evidence of lipid oxidation in this gadoid species of relatively high fat content (2–4%) was also obtained. In minced flesh the rates of deterioration were about twice as fast as in fillets. Holding round fish for up to 6 days in refrigerated sea water (RSW) at 0–1 C before processing extended the frozen storage life of fillets at −10 C by 2–3 wk and of minced flesh by 1 wk over that for comparable materials prepared from round fish held in ice. Materials prepared from winter (March) and summer (August) fish showed little or no difference in rates of deterioration. The susceptibility of silver hake to deterioration at −10 C is similar to cusk; deterioration is faster than in cod or haddock, but not as fast as in red hake (Urophycis chuss). In all silver hake materials negligible deterioration occurred during frozen storage at −26 C for up to 6 mo.During preprocessing storage of round silver hake in RSW, a firm texture and acceptable appearance were retained for several days longer than in round fish held in ice, where objectionable softening of the flesh occurred, particularly in summer-caught fish. Saturation of the sea water with CO2 retarded the onset of bacterial spoilage in RSW-held fish, which otherwise developed more rapidly than in iced fish.

Polyphosphate Treatment of Frozen Cod. 2. Effect on Drip, Yield, Lipid Hydrolysis and Protein Extractability in Twice-Frozen Newfoundland Summer Trap and Fall Cod

1964 ◽  
Vol 21 (3) ◽  
pp. 539-548 ◽  
Author(s):  
W. A. MacCallum ◽  
H. S. Shieh ◽  
Dorothy A. Chalker ◽  
W. J. Dyer ◽  
D. R. Idler
Keyword(s):  
Gadus Morhua ◽  
Protein Denaturation ◽  
Sodium Tripolyphosphate ◽  
Fatty Acid Production ◽  
Lipid Hydrolysis ◽  
Fish Samples ◽  
Frozen Fish ◽  
Free Fatty Acid Production ◽  
Protein Extractability ◽  
Better Than

Thaw-drip from once-frozen fall-caught Newfoundland cod (Gadus morhua L.), thawed after storage at −23 °C for up to [Formula: see text] weeks, was equal to total drip from twice-frozen fish treated with sodium tripolyphosphate between freezings. Treatment of twice-frozen cod before the first freezing only had no effect on reducing total thaw-drip below that from twice-frozen untreated samples and the yield, although higher in the former than in the latter, was no better than that from once-frozen untreated fillets. Yields from twice-frozen fish were improved greatly by dipping prior to the second freezing and by dipping before each freezing. Treatment between freezings gave yields close to 100% of initial fillet weight whereas losses with the untreated once- and twice-frozen product appear close to 7 and 15%, respectively.With summer-caught trap fish, characterized by higher thaw-drip values which were not affected by treatment, yields of twice-frozen cod were improved; however, losses were still about 12% in fish treated between freezings.Treatment of twice-frozen cod from the two sources did not appreciably affect lipid hydrolysis or protein denaturation. However, lipid content and free fatty acid production were significantly higher in the trap fish samples as compared to the fall-caught cod.

Yields of protein extracted from a range of northern Victorian herbage

1977 ◽  
Vol 17 (85) ◽  
pp. 268 ◽  
Author(s):  
DR McKenzie
Keyword(s):  
White Clover ◽  
Nitrogen Fertilizer ◽  
Perennial Grass ◽  
Protein Yield ◽  
Leaf Protein ◽  
Protein Concentrate ◽  
Leaf Protein Concentrate ◽  
Extractable Protein ◽  
Protein Extractability ◽  
Clover Content

Leaf protein concentrate was extracted and measured in a range of commonly grown pasture plants and cereals in Victoria, with the aim of identifying species most suitable for a leaf protein concentrate industry. The effects of sward maturity, nitrogen fertilizer and pH, on protein extractability were examined. Best yields (1100 to 1500 kg ha-1) of extractable protein were obtained from irrigated lucerne and white clover. Extractable protein yield from perennial grass, cereals and lucerne declined rapidly with maturity, whereas lupins, vetch and white clover were much less affected by maturity. Soursob in mixed pasture reduced yields by reducing pH of juice. Nitrogen fertilizer applied in spring on a mixed pasture reduced the clover content and consequently the extractable protein yield.

The Effect of Vitamin A on the Intermittent Nitrogen Dioxide Gas Exposure in Hamsters

1976 ◽  
Vol 34 ◽  
pp. 176-177
Author(s):  
J.C.S. Kim ◽  
M.G. Jourden ◽  
E.S. Carlisle
Keyword(s):  
Electron Microscopy ◽  
Vitamin A ◽  
Nitrogen Dioxide ◽  
Chronic Exposure ◽  
Light And Electron Microscopy ◽  
Specific Effect ◽  
Deficient Diet ◽  
Intermittent Exposure ◽  
Hypovitaminosis A ◽  
Gas Exposure

Chronic exposure to nitrogen dioxide in rodents has shown that injury reaches a maximum after 24 hours, and a reparative adaptive phase follows (1). Damage occurring in the terminal bronchioles and proximal portions of the alveolar ducts in rats has been extensively studied by both light and electron microscopy (1).The present study was undertaken to compare the response of lung tissue to intermittent exposure to 10 ppm of nitrogen dioxide gas for 4 hours per week, while the hamsters were on a vitamin A deficient diet. Ultrastructural observations made from lung tissues obtained from non-gas exposed, hypovitaminosis A animals and gas exposed animals fed a regular commercially prepared diet have been compared to elucidate the specific effect of vitamin A on nitrogen dioxide gas exposure. The interaction occurring between vitamin A and nitrogen dioxide gas has not previously been investigated.

Platelet-Bound Prekallikrein Promotes Pro-Urokinase-Induced Clot Lysis: A Mechanism for Targeting the Factor XII Dependent Intrinsic Pathway of Fibrinolysis

1994 ◽  
Vol 71 (03) ◽  
pp. 347-352 ◽  
Author(s):  
Jean-Pierre Loza ◽  
Victor Gurewich ◽  
Michael Johnstone ◽  
Ralph Pannell
Keyword(s):  
Platelet Rich Plasma ◽  
Specific Inhibitor ◽  
Specific Effect ◽  
Clot Lysis ◽  
Factor Xii ◽  
Intrinsic Pathway ◽  
Clot Retraction ◽  
Enzymatic Mechanism ◽  
Low Concentrations ◽  
Factor Xiia

SummaryClots formed from platelet rich plasma were found to be lysed more readily by low concentrations of pro-urokinase (pro-UK) than clots formed from platelet poor plasma. This was not a non-specific effect since the reverse occurred with tissue plasminogen activator. A mechanical explanation due to platelet-mediated clot retraction was excluded by experiments in which retraction was inhibited with cyto-chalasin B. Therefore, a platelet-mediated enzymatic mechanism was postulated to explain the promotion of fibrinolysis. Casein autography of isolated platelets revealed a ≈ 90 kDa band of activity which comigrated with plasma prekallikrein (PK)/kallikrein, a known activator of pro-UK. Furthermore, treatment of platelets with plasma PK activator (PPA), consisting essentially of factor XIIa, induced activation of pro-UK and of chromomgenic substrate for kallikrein (S-2302). This activity corresponded to approximately 40-200 pM kallikrein per 10 8 washed and gel filtered platelets per ml. The activation of pro-UK by PPA-pretreated platelets was dose-dependent and inhibited by soybean trypsin inhibitor but not by bdellin, a specific inhibitor of plasmin, nor by the corn inhibitor of factor XIIa. Kinetic analysis of pro-UK activation by kallikrein showed promotion of the reaction by platelets. The KM of the reaction was reduced by platelets by ≈ 7-fold, while the kcat was essentially unchanged. In conclusion, PK was shown to be tightly associated with platelets where it can be activated by factor XIIa during clotting. The activation of pro-UK by platelet-bound kallikrein provides an explanation for the observed platelet mediated promotion of pro-UK-induced clot lysis. Since pro-UK and plasminogen have also been shown to be associated with platelets, the present findings suggest a mechanism by which the factor Xlla-dependent intrinsic pathway of fibrinolysis can be localized and targeted to a thrombus.

The Effects of Heparin and Annexin V on Fibrin Accretion after Injury in the Jugular Veins of Rabbits

1993 ◽  
Vol 69 (03) ◽  
pp. 227-230 ◽  
Author(s):  
J Van Ryn-McKenna ◽  
H Merk ◽  
T H Müller ◽  
M R Buchanan ◽  
W G Eisert
Keyword(s):  
Vessel Wall ◽  
Thrombin Generation ◽  
Antithrombin Iii ◽  
Specific Effect ◽  
Annexin V ◽  
Inhibitory Effect ◽  
Jugular Veins ◽  
Prothrombinase Complex ◽  
Wall Injury

SummaryWe compared the relative abilities of unfractionated heparin and annexin V to prevent fibrin accretion onto injured jugular veins in vivo. Heparin was used to accelerate the inhibition of thrombin by antithrombin III, and annexin V was used to inhibit the assembly of the prothrombinase complex on phospholipid surfaces, thereby blocking thrombin generation. Rabbit jugular veins were isolated in situ, a 2 cm segment was injured by perfusing it with air, and then blood flow was re-established. Five minutes later, each rabbit was injected with heparin (20 U/kg) or annexin V (0.3 mg/kg) and then with 125I-fibrinogen. The amount of 125I-fibrin accumulation onto each injured vessel wall segment was measured 4 h later. Each injured vessel was completely deendothelialized as a result of the air perfusion as demonstrated by electron microscopy. 125I-fibrin accretion onto the injured jugular veins was enhanced 2.4-fold as compared to the uninjured veins in sham-operated animals. Heparin treatment did not reduce fibrin accretion, whereas, annexin V treatment decreased fibrin accretion by 60%, p <0.05. This latter effect was achieved without sustained circulating anticoagulation. Additional experiments confirmed that the inhibitory effect of annexin V on fibrin accretion was associated with a surface specific effect, since more annexin V bound to the injured jugular vein segments as compared to the non-injured jugular veins. We conclude that, i) mild vessel wall injury (selective de-endothelialization) in veins results in a thrombogenic vessel wall; ii) the thrombogenecity of which is not inhibited by prophylactic doses of heparin; but iii) is inhibited by annexin V, which binds to injured vessel wall surface, and inhibits thrombin generation independently of antithrombin III.

The Influence of Serotonin on Clot Retraction and the Thrombelastogram

1958 ◽  
Vol 02 (01/02) ◽  
pp. 111-124 ◽  
Author(s):  
E Deutsch ◽  
K Martiny
Keyword(s):  
Human Plasma ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Specific Effect ◽  
High Dose ◽  
Clot Retraction ◽  
Platelet Counts ◽  
Essential Value ◽  
High Doses ◽  
Free Plasma

Summary1. Normal platelets are necessary for induction of normal clot retraction.2. Serotonin does not induce retraction in human platelet-free plasma-clots or enhance clot firmness as measured in the coagulogram.3. Serotonin does not improve clot retraction or firmness in plasma clots with sub-optimal platelet counts.4. Methylserotonin inhibits clot retraction of platelet-rich plasma to a certain extent in moderate doses, whereas, high doses are ineffective. BOL 148 has a similar, but less significant action. There is a possibility that these effects are specific antiserotonin-effects.5. LSD 25 was ineffective in all concentrations used.6. Largactil and reserpin inhibit retraction in high doses. There seems to be a non specific effect caused by the high dose.7. Reserpine does not release a retraction-inducing agent from the platelets, which could be detected in the centrifuged platelet-free plasma used for the incubation.8. Serotonin does not replace the retraction-cofactor of Hartert, or the dialyzable factor of Lüscher in synthetic clotting substrates.9. Serotonin is of no essential value in inducing normal retraction of human plasma clots.

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