Metabolic cold adaptation of polar fish based on measurements of aerobic oxygen consumption: fact or artefact? Artefact!

2002 ◽  
Vol 132 (4) ◽  
pp. 789-795 ◽  
Author(s):  
John Fleng Steffensen
Keyword(s):  
Oxygen Consumption ◽  
Cold Adaptation ◽  
Polar Fish ◽  
Metabolic Cold Adaptation

Metabolic opportunists: feeding and temperature influence the rate and pattern of respiration in the high arctic woollybear caterpillar gynaephora groenlandica (Lymantriidae)

1999 ◽  
Vol 202 (1) ◽  
pp. 47-53 ◽  
Author(s):  
V.A. Bennett ◽  
O. Kukal ◽  
R.E. Lee
Keyword(s):  
Cold Adaptation ◽  
Freeze Tolerance ◽  
High Arctic ◽  
Temperature Influence ◽  
Temperature Changes ◽  
Respiration Rates ◽  
Polar Environment ◽  
Lepidopteran Larvae ◽  
Gynaephora Groenlandica ◽  
Metabolic Cold Adaptation

Arctic woollybear caterpillars, Gynaephora groenlandica, had the capacity to rapidly and dramatically increase respiration rates up to fourfold within 12–24 h of feeding and exhibited similar decreases in respiration of 60–85 % in as little as 12 h of starvation. At the peak of their feeding season, the respiration rates of caterpillars also increased significantly with temperature from 0.5 to 22 degreesC for both fed and starved caterpillars (Q10=1-5). Indicative of diapause, late season caterpillars had depressed respiration rates which were less sensitive to temperature changes (Q10 approximately 1.5), while respiration rates for caterpillars that had spun hibernacula were even lower. G. groenlandica did not appear to demonstrate metabolic cold adaptation compared with other temperate lepidopteran larvae. The seasonal capacity to adjust metabolic rate rapidly in response to food consumption and temperature (which can be elevated by basking) may promote the efficient acquisition of energy during the brief (1 month) summer growing and feeding season, while conserving energy by entering diapause when conditions are less favorable. These adaptations, along with their long 15–20 year life cycle and the retention of freeze tolerance year-round, promote the survival of G. groenlandica in this harsh polar environment.

scholarly journals Metabolic cold adaptation in fishes occurs at the level of whole animal, mitochondria and enzyme

2011 ◽  
Vol 279 (1734) ◽  
pp. 1740-1747 ◽  
Author(s):  
Craig R. White ◽  
Lesley A. Alton ◽  
Peter B. Frappell
Keyword(s):  
High Latitude ◽  
Cold Adaptation ◽  
Citrate Synthase ◽  
High Standard ◽  
Metabolic Rates ◽  
Thermal Plasticity ◽  
Metabolic Compensation ◽  
Low Latitudes ◽  
Effects Of Temperature ◽  
Metabolic Cold Adaptation

Metabolic cold adaptation (MCA), the hypothesis that species from cold climates have relatively higher metabolic rates than those from warm climates, was first proposed nearly 100 years ago and remains one of the most controversial hypotheses in physiological ecology. In the present study, we test the MCA hypothesis in fishes at the level of whole animal, mitochondria and enzyme. In support of the MCA hypothesis, we find that when normalized to a common temperature, species with ranges that extend to high latitude (cooler climates) have high aerobic enzyme (citrate synthase) activity, high rates of mitochondrial respiration and high standard metabolic rates. Metabolic compensation for the global temperature gradient is not complete however, so when measured at their habitat temperature species from high latitude have lower absolute rates of metabolism than species from low latitudes. Evolutionary adaptation and thermal plasticity are therefore insufficient to completely overcome the acute thermodynamic effects of temperature, at least in fishes.

Nonshivering thermogenesis induced by repetitive cooling of spinal cord in the rat

1976 ◽  
Vol 230 (3) ◽  
pp. 720-723 ◽  
Author(s):  
M Banet ◽  
H Hensel
Keyword(s):  
Spinal Cord ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Rectal Temperature ◽  
Cold Adaptation ◽  
White Male ◽  
Metabolic Effect ◽  
Male Rat ◽  
Nonshivering Thermogenesis ◽  
Experimental Animals

The effect of prolonged and repetitive cooling of the spinal cord on the sensitivity to the metabolic effect of exogenous noradrenaline and on the resistance to cold exposure was studied in the white male rat. The spinal cord of 10 animals was cooled for an average of 90 h-9 h/day 5 days/wk - to a level that induced an increase in oxygen uptake of almost 70%. Oxygen consumption was then measured at 30 degrees C before and 1 h after a subcutaneous injection of noradrenaline (0.4 mg/kg). Following the noradrenaline injection, the experimental animals increased oxygen uptake by 71%, while the control ones increased it by only 33% (P less than 0.01). During exposure to -20 degrees C, the experimental animals, despite their increased capacity for nonshivering thermogenesis, did not maintain rectal temperature longer than the control ones, thus showing that other factors also play a significant role in cold adaptation in the rat.

Sign in / Sign up

Export Citation Format

Share Document