Phylogenetic differences of mammalian basal metabolic rate are not explained by mitochondrial basal proton leak

Polymeropoulos, E. T. and Heldmaier, G. and Frappell, P. B. and McAllan, B. M. and Withers, K. W. and Klingenspor, M. and White, C. R. and Jastroch, M. (2012) Phylogenetic differences of mammalian basal metabolic rate are not explained by mitochondrial basal proton leak. Proceedings of the Royal Society of London: Biological Sciences, 279 (1726). pp. 185-193. ISSN 0962-8452

Abstract

Metabolic rates of mammals presumably increased during the evolution of endothermy, but molecular and cellular mechanisms underlying basal metabolic rate (BMR) are still not understood. It has been established that mitochondrial basal proton leak contributes significantly to BMR. Comparative studies among a diversity of eutherian mammals showed that BMR correlates with body mass and proton leak. Here, we studied BMR and mitochondrial basal proton leak in liver of various marsupial species. Surprisingly, we found that the mitochondrial proton leak was greater in marsupials than in eutherians, although marsupials have lower BMRs. To verify our finding, we kept similar-sized individuals of a marsupial opossum (Monodelphis domestica) and a eutherian rodent (Mesocricetus auratus) species under identical conditions, and directly compared BMR and basal proton leak. We confirmed an approximately 40 per cent lower mass specific BMR in the opossum although its proton leak was significantly higher (approx. 60%). We demonstrate that the increase in BMR during eutherian evolution is not based on a general increase in the mitochondrial proton leak, although there is a similar allometric relationship of proton leak and BMR within mammalian groups. The difference in proton leak between endothermic groups may assist in elucidating distinct metabolic and habitat requirements that have evolved during mammalian divergence.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published Version restricted access in accordance with the copyright policy of the publisher (Royal Society)
Depositing User: Mrs Julie-Anne Christensen
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 01 Oct 2012 08:56
Last Modified: 09 Oct 2013 06:37
Uncontrolled Keywords: marsupials; eutherians; basal metabolic rate; mitochondria; basal proton leak; liver
Fields of Research (FOR2008): 06 Biological Sciences > 0606 Physiology > 060603 Animal Physiology - Systems
06 Biological Sciences > 0608 Zoology > 060802 Animal Cell and Molecular Biology
06 Biological Sciences > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9608 Flora, Fauna and Biodiversity > 960899 Flora, Fauna and Biodiversity of Environments not elsewhere classified
Identification Number or DOI: 10.1098/rspb.2011.0881
URI: http://eprints.usq.edu.au/id/eprint/21263

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