Low temperature acclimation decreases rates of protein synthesis in rainbow trout (Oncorhynchus mykiss) heart

1995 ◽  
Vol 14 (1) ◽  
pp. 63-69 ◽  
Author(s):  
D. H. Sephton ◽  
W. R. Driedzic
Keyword(s):  
Protein Synthesis ◽  
Rainbow Trout ◽  
Low Temperature ◽  
Oncorhynchus Mykiss ◽  
Temperature Acclimation ◽  
Rainbow Trout Oncorhynchus Mykiss

Synthesis of stress protein 70 (Hsp70) in rainbow trout (Oncorhynchus mykiss) red blood cells

1997 ◽  
Vol 200 (3) ◽  
pp. 607-614 ◽  
Author(s):  
S Currie ◽  
B Tufts
Keyword(s):  
Protein Synthesis ◽  
Rainbow Trout ◽  
Heat Shock ◽  
Oncorhynchus Mykiss ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Stress Proteins ◽  
Stress Protein ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Hsp70 Synthesis

Unlike enucleated mammalian red blood cells (rbcs), the nucleated rbcs of lower vertebrates are capable of protein synthesis and may, therefore, serve as a valuable model to investigate the adaptive significance of stress protein synthesis in cells. This study examined the synthesis of stress protein 70 (Hsp70) in rbcs of the temperature-sensitive rainbow trout Oncorhynchus mykiss in response to heat shock and anoxia. Through western blot analysis, we have demonstrated that rainbow trout rbcs synthesize Hsp70 both constitutively and in response to an increase in temperature. Radioisotopic labelling experiments indicated that the temperature at which Hsp70 synthesis was induced in fish acclimated to 10 °C was between 20 and 25 °C. Actinomycin D blocked de novo Hsp70 synthesis, implying that synthesis of Hsp70 is regulated at the level of transcription in rainbow trout rbcs. Since trout rbcs rely heavily on aerobic metabolism, but may also experience very low oxygen levels within the circulation, we also examined the relative importance of (1) anoxia as a stimulus for Hsp70 synthesis and (2) oxygen as a requirement for protein synthesis under control and heat-shock conditions. We found that trout rbcs were capable of protein synthesis during 2 h of anoxia, but did not increase Hsp70 synthesis. Moreover, rbcs subjected to combined anoxia and heat shock exhibited increases in Hsp70 synthesis that were similar in magnitude to those in cells exposed to heat shock alone. The latter results suggest that rainbow trout rbcs are (1) able to synthesize non-stress proteins during anoxia, (2) capable of tolerating periods of reduced oxygen availability without increased synthesis of stress proteins and (3) able to maintain the integrity of their heat-shock response even during periods of anoxia.

DETERMINATION OF PROTEIN SYNTHESIS IN RAINBOW TROUT, ONCORHYNCHUS MYKISS, USING A STABLE ISOTOPE

1994 ◽  
Vol 189 (1) ◽  
pp. 279-284
Author(s):  
C Carter ◽  
S Owen ◽  
Z He ◽  
P Watt ◽  
C Scrimgeour ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Rainbow Trout ◽  
Amino Acid ◽  
Oncorhynchus Mykiss ◽  
Considerable Proportion ◽  
Published Data ◽  
Short Term ◽  
Terrestrial Mammals ◽  
Rainbow Trout Oncorhynchus Mykiss

It has been suggested (Houlihan, 1991) that the consumption of 1 g of protein in a variety of species of fish stimulates the synthesis of, approximately, an equal amount of protein. Although synthesis of protein may account for as much as 40 % of the whole-animal oxygen consumption (Lyndon et al. 1992), only about 30 % of the synthesized proteins are retained as growth (Houlihan et al. 1988; Carter et al. 1993a,b). Thus, one focus of attention is the potential advantage gained by fish in allocating a considerable proportion of assimilated energy to protein turnover in contrast to relatively low-cost, low-turnover protein growth (Houlihan et al. 1993). Rates of protein synthesis in several species of fish have been measured using radioactively labelled amino acids, frequently given as a flooding dose (reviewed by Fauconneau, 1985; Houlihan, 1991). These measurements cannot be made for longer than a few hours because of the decline in specific radioactivity in the amino acid free pool. However, as protein synthesis rates vary during the course of a day as a result of the post-prandial stimulation, and since radiolabelled amino acid methodology is invasive, short-term and terminal, it has been difficult to be certain of the relationship between protein growth measured in the long term and protein synthesis rates measured in the short term. This paper addresses these problems by developing a method using 15N in orally administered protein to measure protein synthesis rates in fish over relatively long periods, the aim being to use procedures that are as non-invasive and repeatable as possible. The use of stable isotopes to measure protein metabolism is well established in terrestrial mammals (see Rennie et al. 1991; Wolfe, 1992), but to our knowledge the only published data for aquatic ectotherms are on the blue mussel (Mytilus edulis L.) (Hawkins, 1985). In the present study, rates of protein synthesis of individual rainbow trout [Oncorhynchus mykiss (Walbaum)] were calculated from the enrichment of excreted ammonia with 15N over the 48 h following the feeding of a single meal (dose) containing protein uniformly labelled with 15N by use of an end-point stochastic model (Waterlow et al. 1978; Wolfe, 1992). Application of this type of modelling would appear to be ideal for measuring ammonotelic fish nitrogen metabolism since, unlike the situation in mammals, the catabolic flux of amino acids through urea is very small. Further, ammonia is excreted directly into the surrounding water via the gills and is not stored for any length of time, in contrast to the situation in mammals, so the rate of tracer appearance is easily measurable.

Influence of low temperature acclimation on fate of metabolic fuels in rainbow trout (Oncorhynchus mykiss) hearts

1993 ◽  
Vol 71 (11) ◽  
pp. 2167-2173 ◽  
Author(s):  
John R. Bailey ◽  
William R. Driedzic
Keyword(s):  
Oxygen Consumption ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Temperature Acclimation ◽  
Experimental Conditions ◽  
Intracellular Lipids ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Significant Difference ◽  
Precipitate Protein ◽  
Fuel Source

Rainbow trout (Oncorhynchus mykiss) were acclimated to 5 and 20 °C. Oxygen consumption of isolated perfused hearts was measured at 5 or 15 °C with either glucose or palmitate as the exogenous fuel source. With glucose as the fuel there was no significant difference in oxygen consumption of hearts from either acclimation group at either temperature. With palmitate as the fuel source, hearts from fish acclimated to and tested at 5 °C had significantly higher oxygen consumption than hearts from fish acclimated to 20 °C and tested at either 5 or 15 °C. Hearts from fish both acclimated to and tested at 5 °C had a higher oxygen consumption with palmitate than when glucose was supplied. This reflects the preference for fatty acid fuels found in cold acclimated muscle tissue, and consequently the amount of oxygen required to utilize fats. Under all experimental conditions, 14CO2 production from either (6-14C)glucose or (1-14C)palmitate could account for less than 0.5% of oxygen consumption. Tissue chemical analysis showed that most of the label from (6-14C)glucose appeared in acid-soluble (glycolytic intermediates, citric acid cycle intermediates, amino acids, etc.) and lipid fractions while most of the label from (1-14C)palmitate appeared in lipid- or acid-soluble or acid precipitate (protein material) fractions. This indicates considerable dilution of exogenous fuels in endogenous pools, which could account for the discrepancy in measured O2 consumption and 14CO2 production. Glucose catabolism was little affected by either acute or chronic changes in temperature other than an increase in glucose incorporation into the glycogen pool. Hearts from fish both acclimated to and tested at 5 °C showed an increased handling of exogenous fatty acids as reflected by elevated rates of catabolism and incorporation into intracellular lipids.

Effects of chronic sublethal ammonia and a simulated summer global warming scenario: protein synthesis in juvenile rainbow trout (Oncorhynchus mykiss)

1998 ◽  
Vol 55 (6) ◽  
pp. 1534-1544 ◽  
Author(s):  
Scott D Reid ◽  
T K Linton ◽  
J J Dockray ◽  
D G McDonald ◽  
C M Wood
Keyword(s):  
Protein Synthesis ◽  
Global Warming ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Protein Turnover ◽  
Warming Scenario ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Global Warming Scenario ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Protein synthesis, net accretion, and degradation in liver, gill, and white muscle and ribosomal translational efficiency and protein synthesis capacity in liver and gill were measured using a flooding dose of [3H]phenylalanine in juvenile rainbow trout (Oncorhynchus mykiss). The fish were chronically exposed (90 days) in hardwater to the presence or absence of sublethal ammonia (70 µmol total ammonia ·L-1) alone or in combination with a 2°C elevation in the normal temperature profile over the months of June-September 1993 (ambient temperature range 13-22°C). Chronic sublethal exposure to ammonia had little impact on gill protein synthesis and degradation (protein turnover) and even less in muscle. However, in the liver, both protein synthesis and degradation were stimulated following 60 days of the sublethal ammonia exposure. The 2°C elevation in temperature resulted in a slight increase in protein turnover in both gills and liver. However, during the period of peak water temperature, the 2°C elevation in temperature inhibited protein dynamics in these tissues. Overall, elevated environmental ammonia in combination with a summer global warming scenario would challenge the ability of fish to adapt to alterations in the quality of their environment, most notably during periods of peak temperatures.

scholarly journals Effects of heat shock and hypoxia on protein synthesis in rainbow trout (Oncorhynchus mykiss) cells.

1998 ◽  
Vol 201 (17) ◽  
pp. 2543-2551 ◽  
Author(s):  
S Airaksinen ◽  
C M Råbergh ◽  
L Sistonen ◽  
M Nikinmaa
Keyword(s):  
Protein Synthesis ◽  
Rainbow Trout ◽  
Heat Shock ◽  
Epithelial Cells ◽  
Oncorhynchus Mykiss ◽  
Transcriptional Level ◽  
Specific Response ◽  
Hsp70 Gene ◽  
Hsp70 Mrna ◽  
Rainbow Trout Oncorhynchus Mykiss

We examined the effects of heat stress (from 18 degreesC to 26 degreesC) and low oxygen tension (1% O2=1 kPa) on protein synthesis in primary cultures of hepatocytes, gill epithelial cells and fibroblast-like RTG-2 cells of rainbow trout Oncorhynchus mykiss. All these cell types displayed elevated levels of 67, 69 and 92 kDa proteins, whereas a 104 kDa protein was induced only in RTG-2 cells. Hypoxia induced a cell-type-specific response, increasing the synthesis of 36, 39 and 51 kDa proteins in the gill epithelial cells. The regulation of the heat-shock response in fish hepatocytes showed that an HSF1-like factor is involved in the transcriptional induction of the hsp70 gene. Consequently, there was a pronounced accumulation of hsp70 mRNA. Furthermore, the kinetics of activation of DNA binding and the increase in hsp70 gene expression showed a remarkable correlation, indicating that hsp70 expression is regulated at the transcriptional level in these trout cells.

Cold acclimation increases activities of mitochondrial long-chain acyl-CoA synthetase and carnitine acyl-CoA transferase I in heart of rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 75 (2) ◽  
pp. 324-331 ◽  
Author(s):  
Christopher P. Patey ◽  
William R. Driedzic
Keyword(s):  
Fatty Acid ◽  
Rainbow Trout ◽  
Low Temperature ◽  
Oncorhynchus Mykiss ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Coa Transferase ◽  
Chain Acyl ◽  
Long Chain

Rainbow trout (Oncorhynchus mykiss) were acclimated to 5 or 15 °C. Hearts were excised and assayed for the activity of enzymes essential for fatty acid metabolism. The activity of long-chain acyl-CoA synthetase, the first enzyme required in either fatty acid oxidation or complex fatty acid synthesis, was increased following acclimation to low temperature. Total crude homogenates exhibited an increase in activity with either palmitate (0.037–0.047 μmol/(min∙g)), stearate (0.037–0.055 μmol/(min∙g)), or oleate (0.041–0.064 μmol/(min∙g)) as substrate. Mitochondrial preparations showed the greatest increase in activity with palmitate (0.486–0.962 nmol/(min∙g)) as substrate, whereas microsomal preparations exhibited the greatest increase in activity with oleate (0.976–1.933 nmol/(min∙g)) as substrate. The activity of carnitine acyl-CoA transferase I, which is located on the outer mitochondrial membrane and is required for fatty acid oxidation, increased following acclimation to low temperature with palmitoyl CoA (0.137–0.352 μmol/(min∙g)), stearoyl CoA (0.066–0.152 μmol/(min∙g)), or oleoyl CoA (0.137–0.224 μmol/(min∙g)) as substrate. The parallel increase in mitochondrial long-chain acyl-CoA synthetase and carnitine acyl-CoA transferase I is consistent with previous observations of an elevated capacity of heart to oxidize fatty acids as exogenous fuels following acclimation to low temperature. The increase in microsome-based long-chain acyl-CoA synthetase may contribute to heart growth at low temperature.

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