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Mitochondrial function in seasonal acclimatization versus latitudinal adaptation to cold in the lugworm Arenicola marina (L.).
Physiol Biochem Zool. 2004 Mar-Apr; 77(2):174-86.PB

Abstract

Previous studies in marine ectotherms from a latitudinal cline have led to the hypothesis that eurythermal adaptation to low mean annual temperatures is energetically costly. To obtain more information on the trade-offs and with that the constraints of thermal adaptation, mitochondrial functions were studied in subpolar lugworms (Arenicola marina L.) adapted to summer cold at the White Sea and were compared with those in boreal specimens from the North Sea, either acclimatized to summer temperatures or to winter cold. During summer, a comparison of mitochondria from subpolar and boreal worms revealed higher succinate oxidation rates and reduced Arrhenius activation energies (Ea) in state 3 respiration at low temperatures, as well as higher proton leakage rates in subpolar lugworms. These differences reflect a higher aerobic capacity in subpolar worms, which is required to maintain motor activity at low but variable environmental temperatures--however, at the expense of an elevated metabolic rate. The lower activity of citrate synthase (CS) found in subpolar worms may indicate a shift in metabolic control within mitochondria. In contrast, acclimatization of boreal lugworms to winter conditions elicited elevated mitochondrial CS activities in parallel with enhanced mitochondrial respiration rates. With falling acclimation temperatures, the significant Arrhenius break temperature in state 3 respiration (11 degrees C) became insignificant (5 degrees C) or even disappeared (0 degrees C) at lower levels of Arrhenius activation energies in the cold, similar to a phenomenon known from hibernating vertebrates. The efficiency of aerobic energy production in winter mitochondria rose as proton leakage in relation to state 3 decreased with cold acclimation, indicated by higher respiratory control ratio values and increased adenosine diphosphate/oxygen (ADP/O) ratios. These transitions indicate reduced metabolic flexibility, possibly paralleled by a loss in aerobic scope and metabolic depression during winter cold. Accordingly, these patterns contrast those found in summer-active, cold-adapted eurytherms at high latitudes.

Authors+Show Affiliations

Alfred-Wegener-Institute for Polar and Marine Research, Ecophysiology/Ecotoxicology, Columbusstrasse, 27568 Bremerhaven, Germany. a.sommer@iu-bremen.deNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

15095238

Citation

Sommer, A M., and H O. Pörtner. "Mitochondrial Function in Seasonal Acclimatization Versus Latitudinal Adaptation to Cold in the Lugworm Arenicola Marina (L.)." Physiological and Biochemical Zoology : PBZ, vol. 77, no. 2, 2004, pp. 174-86.
Sommer AM, Pörtner HO. Mitochondrial function in seasonal acclimatization versus latitudinal adaptation to cold in the lugworm Arenicola marina (L.). Physiol Biochem Zool. 2004;77(2):174-86.
Sommer, A. M., & Pörtner, H. O. (2004). Mitochondrial function in seasonal acclimatization versus latitudinal adaptation to cold in the lugworm Arenicola marina (L.). Physiological and Biochemical Zoology : PBZ, 77(2), 174-86.
Sommer AM, Pörtner HO. Mitochondrial Function in Seasonal Acclimatization Versus Latitudinal Adaptation to Cold in the Lugworm Arenicola Marina (L.). Physiol Biochem Zool. 2004 Mar-Apr;77(2):174-86. PubMed PMID: 15095238.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mitochondrial function in seasonal acclimatization versus latitudinal adaptation to cold in the lugworm Arenicola marina (L.). AU - Sommer,A M, AU - Pörtner,H O, PY - 2003/08/13/accepted PY - 2004/4/20/pubmed PY - 2004/7/21/medline PY - 2004/4/20/entrez SP - 174 EP - 86 JF - Physiological and biochemical zoology : PBZ JO - Physiol Biochem Zool VL - 77 IS - 2 N2 - Previous studies in marine ectotherms from a latitudinal cline have led to the hypothesis that eurythermal adaptation to low mean annual temperatures is energetically costly. To obtain more information on the trade-offs and with that the constraints of thermal adaptation, mitochondrial functions were studied in subpolar lugworms (Arenicola marina L.) adapted to summer cold at the White Sea and were compared with those in boreal specimens from the North Sea, either acclimatized to summer temperatures or to winter cold. During summer, a comparison of mitochondria from subpolar and boreal worms revealed higher succinate oxidation rates and reduced Arrhenius activation energies (Ea) in state 3 respiration at low temperatures, as well as higher proton leakage rates in subpolar lugworms. These differences reflect a higher aerobic capacity in subpolar worms, which is required to maintain motor activity at low but variable environmental temperatures--however, at the expense of an elevated metabolic rate. The lower activity of citrate synthase (CS) found in subpolar worms may indicate a shift in metabolic control within mitochondria. In contrast, acclimatization of boreal lugworms to winter conditions elicited elevated mitochondrial CS activities in parallel with enhanced mitochondrial respiration rates. With falling acclimation temperatures, the significant Arrhenius break temperature in state 3 respiration (11 degrees C) became insignificant (5 degrees C) or even disappeared (0 degrees C) at lower levels of Arrhenius activation energies in the cold, similar to a phenomenon known from hibernating vertebrates. The efficiency of aerobic energy production in winter mitochondria rose as proton leakage in relation to state 3 decreased with cold acclimation, indicated by higher respiratory control ratio values and increased adenosine diphosphate/oxygen (ADP/O) ratios. These transitions indicate reduced metabolic flexibility, possibly paralleled by a loss in aerobic scope and metabolic depression during winter cold. Accordingly, these patterns contrast those found in summer-active, cold-adapted eurytherms at high latitudes. SN - 1522-2152 UR - https://www.unboundmedicine.com/medline/citation/15095238/Mitochondrial_function_in_seasonal_acclimatization_versus_latitudinal_adaptation_to_cold_in_the_lugworm_Arenicola_marina__L___ L2 - https://doi.org/10.1086/381468 DB - PRIME DP - Unbound Medicine ER -