美国麦迪逊威斯康星大学Fariba M. Assadi-Porter和Hannah V. Carey研究团队合作取得一项新突破。他们揭示了在冬眠季节，地松鼠通过肠道共生体进行的氮循环增加。相关论文于2022年1月28日发表在《科学》杂志上。

他们揭示了冬眠的 13 条地松鼠 (Ictidomys tridecemlineatus) 中肠道微生物组介导的尿素氮循环。尿素分解肠道微生物将尿素氮结合到宿主吸收的代谢物中，氮重新结合到松鼠的蛋白质库中。在冬末长时间禁食后，尿素氮的再循环最大，此时肠道组织中的尿素转运蛋白丰度和微生物组中的尿素酶基因丰度最高。这些结果揭示了冬眠期间肠道微生物组的功能作用，并提出了尿素氮循环可能有助于其他单胃动物蛋白质平衡的机制。

研究人员表示，冬眠是哺乳动物的一种策略，它利用代谢可塑性来减少能量需求并实现长期禁食。禁食减轻了冬季食物短缺，但消除了饮食中的氮，危害了身体蛋白质平衡。

附：英文原文

Title: Nitrogen recycling via gut symbionts increases in ground squirrels over the hibernation season

Author: Matthew D. Regan, Edna Chiang, Yunxi Liu, Marco Tonelli, Kristen M. Verdoorn, Sadie R. Gugel, Garret Suen, Hannah V. Carey, Fariba M. Assadi-Porter

Issue&Volume: 2022-01-28

Abstract: Hibernation is a mammalian strategy that uses metabolic plasticity to reduce energy demands and enable long-term fasting. Fasting mitigates winter food scarcity but eliminates dietary nitrogen, jeopardizing body protein balance. Here, we reveal gut microbiome–mediated urea nitrogen recycling in hibernating thirteen-lined ground squirrels (Ictidomys tridecemlineatus). Ureolytic gut microbes incorporate urea nitrogen into metabolites that are absorbed by the host, with the nitrogen reincorporated into the squirrel’s protein pool. Urea nitrogen recycling is greatest after prolonged fasting in late winter, when urea transporter abundance in gut tissue and urease gene abundance in the microbiome are highest. These results reveal a functional role for the gut microbiome during hibernation and suggest mechanisms by which urea nitrogen recycling may contribute to protein balance in other monogastric animals.

DOI: abh2950

Source: https://www.science.org/doi/10.1126/science.abh2950