Laboratorio de Biofísica de Membranas, Unidad de Microbiología Básica y Aplicada, Facultad de Ciencias Naturales, Querétaro, Mexico.
Facultad de Ciencias Naturales-Campus Aeropuerto, Universidad Autónoma de Querétaro, Querétaro, Mexico.
Braz J Microbiol. 2021 Jun;52(2):895-903. doi: 10.1007/s42770-021-00427-0. Epub 2021 Jan 21.
Saccharomyces cerevisiae has evolved diverse mechanisms to osmotic changes: the cell wall, ion and water transport systems, and signaling cascades. At the present time, little is known about the mechanisms involved in short-term responses of osmotic stress in yeast or their physiological state during this process. We conducted studies of flow cytometry, wet weight measurements, and electron microscopy to evaluate the modifications in cell volume and the cell wall induced by osmotic stress. In response to osmotic challenges, we show very fast and drastic changes in cell volume (up to 60%), which were completed in less than eight seconds. This dramatic change was completely reversible approximately 16 s after returning to an isosmotic solution. Cell volume changes were also accompanied by adaptations in yeast metabolism observed as a reduction by 50% in the respiratory rate, measured as oxygen consumption. This effect was also fully reversible upon returning to an isosmotic solution. It is noteworthy that we observed a significant recovery in oxygen consumption during the first 10 min of the osmotic shock. The rapid adjustment of the cellular volume may represent an evolutionary advantage, allowing greater flexibility for survival.
细胞壁、离子和水运输系统以及信号级联。目前，对于酵母在短期应对渗透胁迫时涉及的机制及其在这一过程中的生理状态，我们知之甚少。我们进行了流式细胞术、湿重测量和电子显微镜研究，以评估渗透胁迫诱导的细胞体积和细胞壁的变化。在受到渗透挑战时，我们显示细胞体积（高达 60%）发生非常快速和剧烈的变化，这在不到 8 秒的时间内完成。在返回等渗溶液后大约 16 秒，这种剧烈的变化完全是可逆的。细胞体积的变化也伴随着酵母代谢的适应，表现为呼吸速率（以耗氧量衡量）降低 50%。在返回等渗溶液后，这种效应也是完全可逆的。值得注意的是，我们观察到在渗透冲击的前 10 分钟内，耗氧量有明显的恢复。细胞体积的快速调节可能代表了一种进化优势，使其在生存方面具有更大的灵活性。
