Trypsin from Two Strains of Rainbow Trout, Salmo gairdneri, is Influenced Differently by Assay and Acclimation Temperature

1986 ◽  
Vol 43 (8) ◽  
pp. 1664-1667 ◽  
Author(s):  
J. M. McLeese ◽  
E. Don Stevens

Specific activity and kinetic constants of trypsin from the pyloric caeca of two strains of rainbow trout, Salmo gairdneri, were measured using α-N-benzoyl-DL-arginine-ρ-nitroaniline∙HCl No increase in activity was observed with cold acclimation, suggesting that cold acclimation induces no increase in trypsin concentration. The apparent Km for the substrate was independent of assay temperature over the physiological range in both strains, probably to maintain high rates of catalysis at higher temperatures when nutrient requirements are high. Strain A trout produced a trypsin with lower affinity on cold acclimation, but Strain B trout did not. The two strains differed in intestinal morphology as well as in the characteristics of their trypsins.

1979 ◽  
Vol 236 (1) ◽  
pp. R91-R101 ◽  
Author(s):  
J. R. Hazel

Rainbow trout (Salmo gairdneri) acclimated to 5 degrees C possessed larger livers and less neutral lipid per gram of liver than 20 degrees C-acclimated animals; quantities of liver glycolipid, phospholipid, and cholesterol did not vary significantly with acclimation temperature. The relative proportions of phosphatidylethanolamine increased significantly following cold exposure, whereas the quantities of sphingomyelin and cardiolipin declined. For all phosphatides examined (phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, lysolecithin, cardiolipin, sphingomyelin) cold acclimation resulted in 1) an increase in the quantity of polyunsaturated fatty acids, 2) a reduction in the level of saturated fatty acids, and 3) little change in the total content of monoenes and dienes. The increased content of polyunsaturated fatty acids in choline and ethanolamine phosphatides following cold acclimation was confined to the 2-position and occurred at the expense of monoenes and dienes. The relative proportions of n - 3 fatty acids, and less frequently n - 6 fatty acids, increased in phosphatides of cold-acclimated trout, whereas the relative proportions of n - 9 fatty acids declined. These data suggest a preferential incorporation of fatty acids belonging to the linolenic acid family at reduced temperatures. Temperature-induced changes in the chemical composition of trout liver phospholipids counteracted the effects of acute temperature change on nonelectrolyte permeability of isolated liposomes.


1987 ◽  
Vol 129 (1) ◽  
pp. 107-123 ◽  
Author(s):  
A. P. Farrell

A preparation was developed to perfuse the coronary circulation in working hearts from rainbow trout (Salmo gairdneri Richardson). The preparation was used to examine pressure-flow relationships for the coronary circulation as the heart generated physiological and subphysiological work loads. Coronary vascular resistance increased exponentially as coronary flow rate decreased. Coronary resistance was also influenced by cardiac metabolism and acclimation temperature. When heart rate was increased, extravascular compression increased in coronary resistance. Direct vasoconstriction of the coronary vessels, produced by injections of adrenaline into the coronary circulation, was temperature-dependent.


1987 ◽  
Vol 44 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Darrel Jon Laurén ◽  
D. G. McDonald

Whole body, gill, and liver copper uptake, gill Na+-K+-ATPase specific activity, and gill and liver acid-soluble thiols (AST), glutathione, and cysteine of rainbow trout (Salmo gairdneri) were measured during 28 d of exposure to 55 μg copper∙L−1. Na+-K+-ATPase specific activity was inhibited by 33% within 24 h of copper exposure, but this was compensated by a significant increase in microsomal protein so that the total Na+-K+-ATPase activity per milligram of gill tissue returned to normal by day 14. There was no accumulation of copper and no increase in AST, glutathione, or cysteine in the gill. However, after 7 d of exposure, hepatic AST and glutathione had increased by about 2 times, and a sulfhydryl-rich, acid-soluble protein, tentatively identified as metallothionein, increased by 2.8 times. Copper accumulation was highest in the liver, but other tissues also accumulated copper.


1977 ◽  
Vol 55 (4) ◽  
pp. 704-712 ◽  
Author(s):  
L. S. McCarty ◽  
A. H. Houston

Gill and kidney Mg2+-dependent, Na+:K+- and HCO3−-stimulated ATPase (EC 3.6.1.3) activities were estimated at 25 °C and at acclimation temperature in rainbow trout, Salmo gairdneri, acclimated to 2, 10, and 18 °C, as were plasma levels of sodium, potassium, and chloride. Sodium and chloride exhibited no significant variation between 2 and 18 °C; potassium levels were elevated at 18 °C. When assayed at 25 °C Mg2+-dependent and HCO3−-stimulated ATPase activities did not vary consistently or significantly in relation to acclimation temperature. Under comparable assay conditions both gill and kidney Na+:K+-stimulated activities declined at higher acclimation temperatures. Significant increases in all activities were encountered when preparations were incubated at the appropriate acclimation temperature. The data suggest that the branchial Na+:K+–ATPase system serves primarily as a high-temperature amplifier of sodium uptake, and may contribute little to the maintenance of sodium balance in the cold-adapted animal. No evidence of a critical involvement of HCO3−-stimulated ATPase in ionic regulations was obtained.


1977 ◽  
Vol 34 (9) ◽  
pp. 1389-1396 ◽  
Author(s):  
Michael R. Gordon ◽  
Donald J. McLeay

To standardize the sealed-jar bioassay for optimum sensitivity to whole bleached kraft pulpmill effluent, experiments were designed to assess the effects of test temperature, acclimation temperature, and fish species. Coho salmon (Oncorhynchus kisutch) conformed to a previously recognized test paradigm by showing progressively decreased oxygen utilization with increasing toxicant concentrations; however, rainbow trout (Salmo gairdneri) did not. In concentrations of effluent < 1.5 LC50, rainbow trout used significantly more oxygen than control groups, while coho salmon used significantly less oxygen. The sensitivity of these responses was influenced by test temperature and acclimation temperature. Results for coho confirmed that this species was most sensitive to effluent when tested at ambient room temperature. Both species showed significantly decreased oxygen utilization in effluent concentrations > 1.5 LC50 irrespective of test temperature or acclimation temperature. The significance of these responses is discussed, and the applicability of sealed-jar bioassays for assessing the acute toxicity of pulpmill effluents is reviewed. Key words: residual oxygen bioassay, sealed-jar bioassay, pulpmill effluent toxicity, temperature, hyperthermia, respiration, hypoxia, species-specific response


1980 ◽  
Vol 37 (8) ◽  
pp. 1216-1224 ◽  
Author(s):  
Dennis T. Burton ◽  
Alan G. Heath

Rainbow trout (Salmo gairdneri), bluegill (Lepomis macrochirus), and brown bullhead (Ictalurus nebulosus) were exposed to a gradual (over several hours) reduction in dissolved oxygen. Muscle and liver lactic and pyruvic acid concentrations were measured at seven environmental [Formula: see text]. The response was an increase in anaerobic metabolism of the resting fish at a threshold [Formula: see text] that varied with the species and acclimation temperature. A lower anaerobic threshold occurred after acclimation to cold in rainbow trout and possibly bluegill; cold acclimated brown bullhead did not metabolize anaerobically when held in water for 20 min with an oxygen tension near zero. The anaerobic thresholds correspond reasonably well to the relative positions of the blood oxygen dissociation curves for the three species. Only in the trout, however, does the anaerobic threshold found in this study compare to the critical oxygen tension (PC; [Formula: see text] below which aerobic metabolism becomes dependent on [Formula: see text] in the water). PC is far higher in both the bluegill and brown bullhead than the anaerobic threshold which suggests a reduction in overall energy expenditure in these species at rest when in water of low dissolved oxygen.Key words: anaerobic metabolism, lactate/pyruvate ratios, muscle, liver, rainbow trout, Salmo gairdneri; bluegill, Lepomis macrochirus; brown bullhead, Ictalurus nebulosus


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