Biosynthesis of Lecithin by the CDP-Choline Pathway in Liver Microsomes of Rainbow Trout, Salmo gairdneri

1975 ◽  
Vol 32 (9) ◽  
pp. 1633-1637 ◽  
Author(s):  
B. J. Holub ◽  
K. Nilsson ◽  
J. Piekarski ◽  
S. J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Incubation Medium ◽  
Enzymatic Synthesis ◽  
Environmental Temperature ◽  
Incubation Temperature ◽  
Liver Microsomes ◽  
Salmo Gairdneri ◽  
Optimal Activity

The enzymatic synthesis of lecithin from CDP-choline (14C) was characterized in microsomal preparations from the livers of rainbow trout (Salmo gairdneri). Optimal activity was obtained with the addition of 1,2-digylceride and Mg++ to the incubation medium. There was a 290% stimulation in cholinephosphotransferase activity when the incubation temperature was raised from 15 to 37 C. The results indicate that the CDP-choline pathway is operative in the formation of lecithin in the liver of rainbow trout. The possible function of this reaction in the acclimation offish to environmental temperature is discussed.

Incorporation of Fatty Acids into Phosphatidylcholine by Acyl-CoA: l-acyl-sn-glycero-3-phosphorylcholine Acyltransferase in Liver of Rainbow trout, Salmo gairdneri

1976 ◽  
Vol 33 (12) ◽  
pp. 2821-2826 ◽  
Author(s):  
B. J. Holub ◽  
J. Piekarski ◽  
C. Y. Cho ◽  
S. J. Slinger
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Rainbow Trout ◽  
Acid Composition ◽  
Incubation Medium ◽  
Environmental Temperature ◽  
Salmo Gairdneri ◽  
Coa Hydrolase ◽  
Cellular Phospholipid

The formation of phosphatidylcholine by acylation of 1-acyl-sn-glycero-3-phosphorylcholine with fatty acids was demonstrated in microsomal preparations from the livers of rainbow trout (Salmo gairdneri). Maximum incorporation of fatty acids into phosphatidylcholine was highly dependent upon the addition of 1-acyl-sn-glycero-3-phosphorylcholine to the incubation medium when activated acids in the form of [14C]acyl-CoA esters were provided. The acyl-CoA: 1-acyl-sn-glycero-3-phosphorylcholine acyltransferase showed a selectivity for unsaturated (oleate) over saturated (palmitate) fatty acids when microsomes were prepared from rainbow trout acclimated to 7 or 15 C and assays conducted at both temperatures. The presence of an acyl-CoA hydrolase in the microsomal preparations is also reported. The possible function of the acyltransferase in rearranging the fatty acid composition of cellular phospholipid when fish are exposed to a change in environmental temperature is discussed.

Role of gravel substrate on ova survival and alevin emergence of rainbow trout, Salmo gairdneri

1981 ◽  
Vol 59 (4) ◽  
pp. 629-636 ◽  
Author(s):  
Larry D. Witzel ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Incubation Temperature ◽  
Salmo Gairdneri ◽  
Void Space ◽  
Poor Survival ◽  
Percent Survival ◽  
Gravel Size ◽  
Wet Weight ◽  
Developmental Condition

The role of gravel size of unigranular diameters 2, 4, 8, 16, and 26.5 mm on ova survival and subsequent emergence of rainbow trout alevins is examined using a vertical-flow incubation apparatus. Survival to emergence, time of emergence, and alevin condition at emergence were signficantly influenced [Formula: see text] by gravel size. Mean percent survival to emergence increased with gravel size from a minimum of 1% in the 2-mm gravel to a maximum of 76% in the 26.5-mm gravel. Survival of control ova from gravel-free incubator was 88% to swim-up stage. Differences in percent survival were most significant within the 2 to 8 mm range. Poor survival of trout alevins in the finer gravels (2–4 mm) was the result of insufficient void space (entrapment). Days to first (43–58 days after ova burial) and 50% emergence (49–62 days after ova burial) also increased with gravel size. At a mean incubation temperature of 10.6 °C, the total emergence days was greatest (40 days) from the 8-mm gravel and occurred prematurely on day 37 after ova burial in 2-mm gravel. Alevin length and weight varied directly with gravel size, ranging from 2.17 to 2.39 cm and 11.9 to 126.8 mg, respectively. Larger alevins, which emerged later from coarser gravels had the least yolk reserve [Formula: see text] and the lowest KD values [Formula: see text], where KD is a developmental condition factor calculated from the ratio of wet weight to standard length. Premature emergence of free embryos and shortening of the alevin îmergence period in 2.0-mm gravel is identified as a stress response.

In vitro study of hepatic iodothyronine deiodination in rainbow trout, Salmo gairdneri

1983 ◽  
Vol 61 (3) ◽  
pp. 547-552 ◽  
Author(s):  
N. J. Pimlott ◽  
J. G. Eales
Keyword(s):  
Rainbow Trout ◽  
Incubation Temperature ◽  
In Vitro Study ◽  
Outer Ring ◽  
Salmo Gairdneri ◽  
Ph Optimum ◽  
Vitro Assay ◽  
Liver Homogenates ◽  
Mammalian Counterpart

A rapid method involving radioiodide separation by miniature G-25 Sephadex columns was used for in vitro assay of outer-ring deiodination of labeled thyroxine ([125I]T4) and 3,5,3′-triiodo-L-thyronine ([125I]T3) by liver homogenates of rainbow trout acclimated at 12 °C. T4 deiodination depended on time, enzyme (protein) level, substrate (T4) level, and pH (optimum, 6.8–7.4). Boiling eliminated deiodination. Over the range 12–20 °C incubation temperature modified both Km and Vmax values but did not alter the pH optimum. Deiodination was accompanied by [125I]T3 production, but 125I-labeled reverse T3 was not detected. T4 deiodination was unaltered by addition of carrier T3 or T3 removal by immunosequestration. T3 itself underwent no outer-ring deiodination at 12 °C and weak deiodination at 20 °C (pH optimum 6.8–7.4). In conclusion, trout liver posseses a T4 5′-monodeiodinase with several properties similar to those of its mammalian counterpart but with little tendency to deiodinate T3.

scholarly journals Carbonic anhydrase (acetazolamide-sensitive esterase) activity in the blood, gill and kidney of the thermally acclimated rainbow trout, Salmo gairdneri

1978 ◽  
Vol 73 (1) ◽  
pp. 15-27
Author(s):  
A. H. Houston ◽  
L. S. McCarty
Keyword(s):  
Rainbow Trout ◽  
Carbonic Anhydrase ◽  
Incubation Temperature ◽  
Carbonic Anhydrase Activity ◽  
Salmo Gairdneri ◽  
Plasma Sodium ◽  
Blood Levels ◽  
Acclimation Temperature ◽  
Chloride Uptake ◽  
Intimate Association

1. Gill, kidney and blood levels of acetazolamide-sensitive esterase (carbonic anhydrase) activity were estimated at acclimation temperature and at a common temperature (25 degrees C) in rainbow trout acclimated to 2, 10 and 18 degrees C. Plasma levels of sodium, potassium and chloride were also examined for possible acclimatory variations. 2. Plasma sodium and chloride levels, and the sodium:chloride ratio were unaffected by thermal acclimation; potassium concentrations were significantly elevated at 18 degrees C. 3. Significant, but modest changes in renal and branchial carbonic anhydrase activity were observed under physiologically realistic incubation temperature conditions. Blood carbonic anhydrase activity was sharply elevated at higher acclimation temperatures. 4. The data are discussed in relation to the hypothesis that carbonic anhydrase in this relatively stenothermal freshwater salmonid, through its intimate association with the coupled HCO-3/CL- and H+ +NH+4/Na+ exchange systems may provide for relatively thermostable basal rates of sodium and chloride uptake from the medium and recovery from urine. The renal, and more notably the branchial (Na+/K+)-stimulated ATPase systems, and erythrocytic carbonic anhydrase may then serve primarily as high-temperature amplifiers of sodium and chloride recruitment respectively.

Sign in / Sign up

Export Citation Format

Share Document