Extreme physiological plasticity in a hibernating basoendothermic mammal, Tenrec ecaudatus
Extreme physiological plasticity in a hibernating basoendothermic mammal, Tenrec ecaudatus
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DOI：
10.1242/jeb.185900
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发表时间：
2018-10
影响因子：
2.8
通讯作者：
Michael D Treat;Lori Scholer;Brandon Barrett;A. Khachatryan;Austin McKenna;T. Reyes;Alhan Rezazadeh;Charles F. Ronkon;Dan Samora;J. F. Santamaria;Claudia Silva Rubio;Evan Sutherland;Jeffrey Richardson;J. Lighton;F. van Breukelen
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文献类型：
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作者：
Michael D Treat;Lori Scholer;Brandon Barrett;A. Khachatryan;Austin McKenna;T. Reyes;Alhan Rezazadeh;Charles F. Ronkon;Dan Samora;J. F. Santamaria;Claudia Silva Rubio;Evan Sutherland;Jeffrey Richardson;J. Lighton;F. van Breukelen
摘要 生理可塑性使生物体能够对不同的条件做出反应。然而，过于塑料化真的有害吗？马达加斯加常见的马岛礁（Tenrec ecudatus）具有许多拟形特征，可能代表一种基础胎盘哺乳动物。我们建立了 T. ecudatus 的实验室种群，并发现其体温调节和新陈代谢具有极大的可塑性、一种新颖的冬眠形式、可变的年度时间以及显着的生长和繁殖生物学。例如，即使马岛实体完全活跃，其体温 (Tb) 也可能接近环境温度低至 12°C。相反，马岛猬可以在温度为 28°C 的情况下冬眠。在活动季节，耗氧量可能会变化 25 倍，而 Tb 变化很小或没有变化。在南半球的冬季，马岛礁始终处于麻木状态，但麻木的深度可能会有所不同。翻正分析显示，Tb 有助于但不决定活性状态。稳态过程并不总是相互关联的，例如冬眠的马岛猬在保持恒定的体温和耗氧率的同时，心率下降了约 34%。 Tenrec 的生长速度各不相同，但幼体可能在断奶前 5 周内生长约 40 倍，并且成年后可能具有不确定的生长。尽管具有如此深刻的可塑性，马岛珊瑚却令人惊讶地无法忍受极端环境温度（34°C）。我们认为，虽然可塑性可能在持续温和的环境中赋予许多能量优势，但极端环境可能限制了可塑性基础哺乳动物的成功和分布。亮点文章：普通马岛礁（Tenrec ecaudatus）可能是祖先胎盘哺乳动物的代表，表现出极高的生理可塑性。
ABSTRACT Physiological plasticity allows organisms to respond to diverse conditions. However, can being too plastic actually be detrimental? Malagasy common tenrecs, Tenrec ecaudatus, have many plesiomorphic traits and may represent a basal placental mammal. We established a laboratory population of T. ecaudatus and found extreme plasticity in thermoregulation and metabolism, a novel hibernation form, variable annual timing, and remarkable growth and reproductive biology. For instance, tenrec body temperature (Tb) may approximate ambient temperature to as low as 12°C even when tenrecs are fully active. Conversely, tenrecs can hibernate with Tb of 28°C. During the active season, oxygen consumption may vary 25-fold with little or no change in Tb. During the austral winter, tenrecs are consistently torpid but the depth of torpor may vary. A righting assay revealed that Tb contributes to but does not dictate activity status. Homeostatic processes are not always linked, e.g. a hibernating tenrec experienced a ∼34% decrease in heart rate while maintaining constant body temperature and oxygen consumption rates. Tenrec growth rates vary but young may grow ∼40-fold in the 5 weeks until weaning and may possess indeterminate growth as adults. Despite all of this profound plasticity, tenrecs are surprisingly intolerant of extremes in ambient temperature (34°C). We contend that while plasticity may confer numerous energetic advantages in consistently moderate environments, environmental extremes may have limited the success and distribution of plastic basal mammals. Highlighted Article: Common tenrecs, Tenrec ecaudatus, which may be representative of ancestral placental mammals, demonstrate extreme physiological plasticity.