High-resolution mass measurements of single budding yeast reveal linear growth segments

The regulation of cell growth has fundamental physiological, biotechnological and medical implications. However, methods that can continuously monitor individual cells at sufficient mass and time resolution hardly exist. Particularly, detecting the mass of individual microbial cells, which are much smaller than mammalian cells, remains challenging. Here, we modify a previously described cell balance ('picobalance') to monitor the proliferation of single cells of the budding yeast, Saccharomyces cerevisiae, under culture conditions in real time. Combined with optical microscopy to monitor the yeast morphology and cell cycle phase, the picobalance approaches a total mass resolution of 0.45 pg. Our results show that single budding yeast cells (S/G2/M phase) increase total mass in multiple linear segments sequentially, switching their growth rates. The growth rates weakly correlate with the cell mass of the growth segments, and the duration of each growth segment correlates negatively with cell mass. We envision that our technology will be useful for direct, accurate monitoring of the growth of single cells throughout their cycle. Measuring the mass of individual microbial cells remains challenging. Here, the authors present a cell balance to monitor the proliferation of single budding yeast cells under culture conditions in real time, showing that single cells increase total mass in multiple linear segments of constant growth rates.

Automated summary

The regulation of cell growth is of great significance in physiology, biotechnology, and medicine. However, monitoring the mass and growth of individual cells with high resolution is challenging. In this study, the authors modified a cell balance technique to monitor the proliferation of single yeast cells in real-time. They found that the mass of single yeast cells increases in linear segments of constant growth rates. This technology has the potential to directly and accurately monitor the growth of single cells throughout their cycle.