Holden Kaitlyn G, Hedrick Ashley R, Gangloff Eric J, Hall Steven J, Bronikowski Anne M
Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA.
Department of Zoology, Ohio Wesleyan University, Delaware, Ohio, USA.
J Exp Zool A Ecol Integr Physiol. 2022 Mar;337(3):199-205. doi: 10.1002/jez.2564. Epub 2021 Dec 2.
Temperature affects nearly every aspect of how organisms interact with and are constrained by their environment. Measures of organismal energetics, such as metabolic rate, are highly temperature-dependent and governed through temperature effects on rates of biochemical reactions. Characterizing the relationships among levels of biological organization can lend insight into how temperature affects whole-organism function. We tested the temperature dependence of cellular oxygen consumption and its relationship to whole-animal metabolic rate in garter snakes (Thamnophis elegans). Additionally, we tested whether thermal responses were linked to shifts in the fuel source oxidized to support metabolism with the use of carbon stable isotopes. Our results demonstrate temperature dependence of metabolic rates across levels of biological organization. Cellular (basal, adenosine triphosphate-linked) and whole-animal rates of respiration increased with temperature but were not correlated within or among individuals, suggesting that variation in whole-animal metabolic rates is not due simply to variation at the cellular level, but rather other interacting factors across scales of biological organization. Counter to trends observed during fasting, elevated temperature did not alter fuel selection (i.e., natural-abundance stable carbon isotope composition in breath, δ C ). This consistency suggests the maintenance and oxidation of a single fuel source supporting metabolism across a broad range of metabolic demands.
温度几乎影响着生物体与环境相互作用以及受环境限制的方方面面。生物体能量学的指标，比如代谢率，高度依赖于温度，并受温度对生化反应速率的影响所支配。描述生物组织层次之间的关系有助于深入了解温度如何影响整个生物体的功能。我们测试了束带蛇（秀丽锦蛇）细胞耗氧量的温度依赖性及其与全动物代谢率的关系。此外，我们利用碳稳定同位素测试了热反应是否与氧化以支持代谢的燃料来源的转变有关。我们的结果证明了生物组织各层次代谢率的温度依赖性。细胞（基础的、与三磷酸腺苷相关的）和全动物的呼吸速率随温度升高而增加，但在个体内部或个体之间没有相关性，这表明全动物代谢率的变化并非仅仅归因于细胞水平的变化，而是生物组织不同尺度上的其他相互作用因素。与禁食期间观察到的趋势相反，温度升高并未改变燃料选择（即呼出气体中天然丰度稳定碳同位素组成，δ¹³C）。这种一致性表明在广泛的代谢需求范围内，单一支持代谢的燃料来源的维持和氧化过程。
