Booz Allen Hamilton, 8283 Greensboro Drive, Hamilton Building, McLean, VA, 22102, USA.
University of California, San Diego, Department of Bioengineering, La Jolla, CA, 92093, USA.
Sci Rep. 2018 Dec 21;8(1):18045. doi: 10.1038/s41598-018-35936-w.
The yeast metabolic cycle (YMC) is a fascinating example of biological organization, in which cells constrain the function of specific genetic, protein and metabolic networks to precise temporal windows as they grow and divide. However, understanding the intracellular origins of the YMC remains a challenging goal, as measuring the oxygen oscillations traditionally associated with it requires the use of synchronized cultures growing in nutrient-limited chemostat environments. To address these limitations, we used custom-built microfluidic devices and time-lapse fluorescence microscopy to search for metabolic cycling in the form of endogenous flavin fluorescence in unsynchronized single yeast cells. We uncovered robust and pervasive metabolic cycles that were synchronized with the cell division cycle (CDC) and oscillated across four different nutrient conditions. We then studied the response of these metabolic cycles to chemical and genetic perturbations, showing that their phase synchronization with the CDC can be altered through treatment with rapamycin, and that metabolic cycles continue even in respiratory deficient strains. These results provide a foundation for future studies of the physiological importance of metabolic cycles in processes such as CDC control, metabolic regulation and cell aging.
酵母代谢循环（YMC）是生物组织的一个引人入胜的例子，在这个例子中，细胞将特定的遗传、蛋白质和代谢网络的功能限制在精确的时间窗口内，以适应其生长和分裂。然而，要理解 YMC 的细胞内起源仍然是一个具有挑战性的目标，因为传统上测量与之相关的氧振荡需要使用在营养有限的恒化器环境中生长的同步培养物。为了解决这些限制，我们使用定制的微流控设备和延时荧光显微镜，在非同步的单个酵母细胞中，以内源性黄素荧光的形式寻找代谢循环。我们发现了与细胞分裂周期（CDC）同步并在四种不同营养条件下振荡的强大而普遍的代谢循环。然后，我们研究了这些代谢循环对化学和遗传扰动的反应，表明它们与 CDC 的相位同步可以通过雷帕霉素处理来改变，并且即使在呼吸缺陷株中，代谢循环也会继续。这些结果为未来研究代谢循环在细胞衰老等过程中的生理重要性提供了基础，如 CDC 控制、代谢调节和细胞衰老。
