Response of protein synthesis to anoxia and recovery in anoxia-tolerant hepatocytes

1993 ◽  
Vol 265 (1) ◽  
pp. R41-R48 ◽  
Author(s):  
S. C. Land ◽  
L. T. Buck ◽  
P. W. Hochachka
Keyword(s):  
Protein Synthesis ◽  
Chrysemys Picta ◽  
Painted Turtle ◽  
Urea Synthesis ◽  
O2 Consumption ◽  
Purine Nucleotide ◽  
Turnover Rates ◽  
Atp Turnover ◽  
Chrysemys Picta Bellii ◽  
Metabolic Suppression

Hepatocytes from the western painted turtle (Chrysemys picta bellii) display a profound metabolic suppression under anoxia. Fractional rates of protein synthesis fell by 92% during 12 h anoxia at 25 degrees C and were indistinguishable from the rate obtained with cycloheximide. Normoxic recovery saw protein synthesis increase to 160% of control values and return to normal after 2 h. The GTP-to-GDP ratio, implicated in the control of translation, fell threefold during anoxia. Purine nucleotide phosphate profiles suggest that this change occurs through increasing concentrations of ADP and GDP, with concentrations of ATP and GTP and total purines remaining constant. The normoxic cost for protein synthesis was calculated at 47.6 +/- 6.8 mmol ATP/g protein. Normoxic protein synthesis accounted for 36% of overall ATP turnover rates, close to the extent of O2 consumption inhibitable by cycloheximide (28%). Under anoxia, the proportion of ATP turnover utilized by protein synthesis did not change significantly. ATP turnover rates for urea synthesis reflected a similar pattern, falling 72% under anoxia. These results reflect the cell's ability to suppress protein synthesis under anoxia in a manner that is coordinated with the reduction in total metabolic rate.

Protein turnover during metabolic arrest in turtle hepatocytes: role and energy dependence of proteolysis

1994 ◽  
Vol 266 (4) ◽  
pp. C1028-C1036 ◽  
Author(s):  
S. C. Land ◽  
P. W. Hochachka
Keyword(s):  
Energy Dependence ◽  
Protein Turnover ◽  
Lactate Production ◽  
Significant Inhibition ◽  
Turnover Rates ◽  
Atp Turnover ◽  
Protein Pool ◽  
Chrysemys Picta Bellii ◽  
Metabolic Arrest ◽  
Energy Dependent

Hepatocytes from the western painted turtle (Chrysemys picta bellii) are capable of a coordinated metabolic suppression of 88% during 10 h of anoxia at 25 degrees C. The energy dependence and role of proteolysis in this suppression were assessed in labile ([3H]Phe-labeled) and stable ([14C]Phe-labeled) protein pools. During anoxia, labile protein half-lives increased from 24.7 +/- 3.3 to 34.4 +/- 3.7 h, with stable protein half-lives increasing from 55.6 +/- 3.4 to 109.6 +/- 7.4 h. The total anoxic mean proteolytic suppression for both pools was 36%. On the basis of inhibition of O2 consumption and lactate production rates by cycloheximide and emetine, normoxic ATP-dependent proteolysis required 11.1 +/- 1.7 mumol ATP.g-1.h-1 accounting for 21.8 +/- 1.4% of total cellular metabolism. Under anoxia this was suppressed by 93% to 0.73 +/- 0.43 mumol ATP.g-1.h-1. Summation of this with protein synthesis ATP turnover rates indicated that under anoxia 45% of total ATP turnover rate was directed toward protein turnover. Studies with inhibitors of energy metabolism indicated that the majority of energy dependence was found in the stable protein pool, with no significant inhibition occurring among the more labile proteins. We conclude that proteolysis is largely energy dependent under normoxia, whereas under anoxia there is a shift to a slower overall proteolytic rate that is largely energy independent and represents loss mostly from the labile protein pool.

Proteomic changes in the brain of the western painted turtle (Chrysemys picta bellii ) during exposure to anoxia

PROTEOMICS ◽  
2015 ◽  
Vol 15 (9) ◽  
pp. 1587-1597 ◽  
Author(s):  
Richard W. Smith ◽  
Phil Cash ◽  
David W. Hogg ◽  
Leslie T. Buck
Keyword(s):  
Chrysemys Picta ◽  
Painted Turtle ◽  
Chrysemys Picta Bellii ◽  
The Brain

scholarly journals Skeletal Muscle Histidine Containing Dipeptide Contents are Increased in Freshwater Turtles (Chrysemys picta bellii) with Cold-Acclimation

2021 ◽  
Author(s):  
Eimear Dolan ◽  
Daniel E Warren ◽  
Roger C Harris ◽  
Craig Sale ◽  
Bruno Gualano ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Temperature Sensitivity ◽  
Ph Regulation ◽  
Chrysemys Picta ◽  
Painted Turtle ◽  
Freshwater Turtles ◽  
Acid Base ◽  
Cold Temperatures ◽  
Chrysemys Picta Bellii ◽  
Buffering Power

Freshwater turtles found in higher latitudes can experience extreme challenges to acid-base homeostasis while overwintering, due to a combination of cold temperatures along with the potential for environmental hypoxia. Histidine containing dipeptides (HCDs; carnosine, anserine and balenine) may facilitate pH regulation in response to these challenges, through their role as pH buffers. We measured the HCDs content of three tissues (liver, cardiac muscle and skeletal muscle) from the anoxia-tolerant painted turtle (Chrysemys picta bellii) acclimated to either 3 or 20 C. HCDs were detected in all tissues, with the highest content shown in the skeletal muscle. Turtles acclimated to 3 C had more HCD in their skeletal muscle than those acclimated to 20 C (carnosine = 20.8 +/- 4.5 vs 12.5 +/- 5.9 mmol/kg DM; ES = 1.59 (95%CI: 0.16 - 3.00), P = 0.013). The higher HCD content observed in the skeletal muscle of the cold-acclimated turtles suggests a role in acid-base regulation in response to physiological challenges associated with living in the cold, with the increase possibly related to the temperature sensitivity of carnosine's dissociation constant and buffering power of the skeletal muscle during anoxic submergence.

First report on the non-native species, Western painted turtle (Chrysemys picta bellii), in the wild, Republic of Korea

2020 ◽  
Vol 38 (1) ◽  
pp. 16-20 ◽  
Author(s):  
Il-Kook Park ◽  
Kyungwon Lee ◽  
Ji-Hyun Jeong ◽  
Hyun-Been Lee ◽  
Kyo Soung Koo
Keyword(s):  
Native Species ◽  
Chrysemys Picta ◽  
Republic Of Korea ◽  
Painted Turtle ◽  
First Report ◽  
Chrysemys Picta Bellii ◽  
In The Wild

Complete suppression of protein synthesis during anoxia with no post-anoxia protein synthesis debt in the red-eared slider turtleTrachemys scripta elegans

2001 ◽  
Vol 204 (24) ◽  
pp. 4353-4360 ◽  
Author(s):  
Keiron P. P. Fraser ◽  
Dominic F. Houlihan ◽  
Peter L. Lutz ◽  
Sandra Leone-Kabler ◽  
Liscia Manuel ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Chrysemys Picta ◽  
Trachemys Scripta ◽  
Complete Suppression ◽  
Trachemys Scripta Elegans ◽  
Dose Method ◽  
Chrysemys Picta Bellii ◽  
Measurable Level ◽  
Normoxic Control ◽  
Rna Concentration

SUMMARYTwo previous studies of the effects of anoxia on protein synthesis in anoxia-tolerant turtles (Trachemys scripta elegans, Chrysemys picta bellii) have generated opposing results. Using the flooding-dose method, we measured the rate of protein synthesis following injection and incorporation of a large dose of radiolabelled phenylalanine to resolve the question of whether anoxia results in a downregulation of protein synthesis. After 1 h of anoxia, levels of protein-incorporated radiolabel indicated that protein synthesis rates in the intestine, heart, liver, brain, muscle and lungs were not significantly different from those of normoxic controls. However, from 1 to 6 h of anoxia, quantities of protein-incorporated radiolabel did not increase, suggesting that protein synthesis had ceased or had decreased below a measurable level. There was also no significant post-anoxia increase in protein synthesis rates above normoxic control levels during 3 h of recovery from anoxia. RNA-to-protein ratios did not change significantly in any tissue except the heart, in which RNA levels decreased below normoxic control levels after 6 h of anoxia. Except in the heart, downregulation of protein synthesis during anoxia does not appear to be mediated by changes in tissue RNA concentration.

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