Carbon Turnover in Tissues of a Passerine Bird: Allometry, Isotopic Clocks, and Phenotypic Flexibility in Organ Size
Carbon Turnover in Tissues of a Passerine Bird: Allometry, Isotopic Clocks, and Phenotypic Flexibility in Organ Size
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DOI：
10.1086/605548
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发表时间：
2009-11-01
影响因子：
1.6
通讯作者：
McWilliams, Scott
中科院分区：
文献类型：
--
作者：
Bauchinger, Ulf;McWilliams, Scott
稳定同位素是生理和行为生态学家的重要工具，尽管其有用性取决于对同位素随时间并入组织的动态的透彻理解。与头发、爪子和羽毛相反，大多数动物组织不断地含有碳（和其他元素），因此碳同位素值可能会随着时间的推移而变化，具体取决于资源使用和组织特定的代谢率。在此，我们报告了雀形目斑胸草雀 (Taeniopygia guttata) 12 种组织的碳周转率。我们测量了小肠 8 天的平均碳保留时间 (tau)；砂囊、肾、肝、胰、腺胃10-13天；心脏、大脑、血液和飞行肌 17-21 天；腿部肌肉和皮肤26-28天。我们使用这些数据以及其他一些已发表的估计值来确认红细胞、全血、肝脏和腿部肌肉的同位素周转率与体重的比例约为 -1/4 次方。我们的数据还支持“同位素时钟”模型的几个关键假设，该模型利用组织之间同位素值的差异以及这些组织周转率的估计来预测自饮食转变以来经过的时间。最后，我们发现，组织间周转率的差异在很大程度上但不能完全解释花园莺在春季穿越撒哈拉沙漠长途飞行期间器官表型灵活性的程度。需要更多的研究来测量各种动物的许多组织中的组织特异性蛋白质合成、代谢率和元素周转。
Stable isotopes are an important tool for physiological and behavioral ecologists, although their usefulness depends on a thorough understanding of the dynamics of isotope incorporation into tissue(s) over time. In contrast to hair, claws, and feathers, most animal tissues continuously incorporate carbon (and other elements), and so carbon isotope values may change over time, depending on resource use and tissue-specific metabolic rates. Here we report the carbon turnover rate for 12 tissues from a passerine bird, the zebra finch (Taeniopygia guttata). We measured average carbon retention time (tau) for 8 d for small intestine; 10-13 d for gizzard, kidney, liver, pancreas, and proventriculus; 17-21 d for heart, brain, blood, and flight muscle; and 26-28 d for leg muscle and skin. We used these data, along with the few other published estimates, to confirm that the fractional rate of isotopic turnover for red blood cells, whole blood, liver, and leg muscle scales with body mass to approximately the -1/4 power. Our data also support several key assumptions of the "isotopic-clock" model, which uses differences in isotope value between tissues, along with estimates of turnover rate of these tissues, to predict time elapsed since a diet shift. Finally, we show that between-tissues differences in turnover rate largely, but not entirely, explain the extent of phenotypic flexibility in organs of garden warblers during their long-distance flight across the Sahara Desert during spring. More studies that measure tissue-specific protein synthesis, metabolic rate, and elemental turnover in many tissues from a variety of animals are needed.