Human activity in space has steadily increased over time. NASA has reported that during space missions the absence of Earth's gravity could lead to a monthly reduction of 1-1.5% in the mineral density of weight-bearing bones. Rehabilitation efforts may not yield success even after astronauts return to Earth. The impacts can be observed in the muscles, the neuro-vestibular system, the heart, and the eyes
[1]. While understanding the effects of microgravity on the human body is essential, sending biological samples into space is expensive and logistically demanding. To overcome this, tools like clinostats have been developed to simulate microgravity conditions on Earth
[2]. This study explores the effects of microgravity using a yeast cell model,
Saccharomyces cerevisiae. Under microgravity, these yeast cells show altered physiological characteristics, such as changes in the size ratio of daughter to mother cells, bud direction, and reduced invasive growth
[3, 4]. Despite existing studies, the connection between microgravity-induced metabolic alterations and their influence on yeast cell morphology and cytoplasmic properties remains poorly understood. To investigate this, yeast cells are exposed to microgravity using a 2D clinostat, and dielectrophoresis
[5] is employed to obtain the dielectric signatures. The cells are suspended in a sugar-based medium, placed in 1.5-ml centrifuge tubes, and subjected to microgravity for 1 to 24 hours at a conductivity of 0.03 S/m, adjusted with 1x PBS. Their behavior is observed, and dielectric signatures are extracted using a double-shell model, which reflects changes in both the membrane and cytoplasm resulting from microgravity exposure. The results reveal significant differences in membrane permittivity and conductivity between microgravity-exposed and control cells, including a marked decrease in the folding factor—indicating smoother cell surfaces. Overall, this research contributes to our understanding of how microgravity affects cellular function and morphology, with implications for both space biology and human health in extraterrestrial environments.
References
[1] Y. Arfat et al., "Physiological effects of microgravity on bone cells," (in eng), no. 1432-0827 (Electronic).
[2] T. Hoson, S. Kamisaka, Y. Masuda, and M. Yamashita, "Changes in plant growth processes under microgravity conditions simulated by a three-dimensional clinostat," The botanical magazine = Shokubutsu-gaku-zasshi, vol. 105, no. 1, pp. 53-70, 1992/03/01 1992, doi: 10.1007/BF02489403.
[3] A. P. M. Fukuda, V. d. L. Camandona, K. J. M. Francisco, R. M. Rios-Anjos, C. Lucio do Lago, and J. R. Ferreira-Junior, "Simulated microgravity accelerates aging in Saccharomyces cerevisiae," Life Sciences in Space Research, vol. 28, pp. 32-40, 2021/02/01/ 2021, doi: https://doi.org/10.1016/j.lssr.2020.12.003.
[4] I. Walther, B. Bechler, O. Müller, E. Hunzinger, and A. Cogoli, "Cultivation of Saccharomyces cerevisiae in a bioreactor in microgravity," Journal of Biotechnology, vol. 47, no. 2, pp. 113-127, 1996/06/27/ 1996, doi: https://doi.org/10.1016/0168-1656(96)01375-2.
[5] N. F. Doost, S. D. R. Yaram, K. Wagner, H. Garg, and S. K. Srivastava, "Bioelectric profiling of Rickettsia montanensis in Vero cells utilizing dielectrophoresis," Journal of Biological Engineering, vol. 19, no. 1, p. 18, 2025/02/18 2025, doi: 10.1186/s13036-025-00487-y.
