Full text not available from this repository.

Abstract

The mitochondrial basal proton leak (MBPL) significantly contributes to high body temperatures (Tb) and basalmetabolic rates (BMR) in endotherms. In endotherms at a given body mass (M), liver MBPL is higher than inectotherms, supporting the notion that MBPL may partly explain the evolutionary increase in metabolic rate(MR), fostering endothermy. Here, we re-addressed this assumption by performing a phylogenetic analysiscomparing all available liver MBPL data for ecto- and endotherms. While MBPL within endotherms negativelyscales with M and BMR as shown previously, MBPL of ectotherms does not scale allometrically with M.Phylogenetic analysis reveals that this result is confounded by a positive scaling coefficient for MBPL with M forreptiles. Strikingly, the reptilian MBPL reaches endothermic levels above a body mass of 6.6 kg. Thus,phylogenetic scaling of MBPL supports previous claims of endotherm-like physiological characteristics in largereptiles. It appears that diversification of ancestral ectothermic tetrapods to a body mass of at least 6 kg mayhave been required to reach a MBPL that is beneficial for sustained high body temperatures. Novel MBPL datafor the lesser hedgehog tenrec, a protoendothermic eutherian that displays reptile-like thermoregulatorypatterns, fall within the endo- and ectothermic allometric regressions. Finally, we add additional evidence thatwithin endotherms, phylogenetic differences in MR do not correlate with MBPL. Collectively, these data suggestthat MBPL does not universally scale with metabolic rate in ecto- or endotherms and that an increasingMBPL with M may have played an important physiological role in the evolutionary history of reptilianthermoregulation.

Item Type:	Article
Authors/Creators:	Polymeropoulos, ET and Oelkrug, R and White, CR and Jastroch, M
Keywords:	mitochondrial proton leak, metabolic rate, allometry, phylogeny, scaling
Journal or Publication Title:	Journal of Thermal Biology
Publisher:	Pergamon-Elsevier Science Ltd
ISSN:	0306-4565
DOI / ID Number:	https://doi.org/10.1016/j.jtherbio.2017.01.013
Copyright Information:	Copyright 2017 Elsevier Ltd.
Related URLs:	UTAS Profile: Polymeropoulos, ET
Item Statistics:	View statistics for this item

Actions (login required)

Item Control Page