The impact of metabolism on aging and cell size in single yeast cells

The aim of this thesis was to determine how metabolism affects yeast aging in single yeast cells using a novel microfluidic device. We first review how cells are able to sense nutrients in their environment and then describe the use of the microfluidic dissection platform that greatly improves our ability to study yeast aging. Using this device, we measured the lifespan of yeast cells growing under standard and calorie restricted conditions. Although calorie restricted conditions were previously shown to extend lifespan, we did not detect any lifespan extension suggesting that method-specific effects are essential to extend lifespan under calorie restricted conditions in yeast. We also used our device to explain why cell size increases as a function of age. We found that repeated rounds of protein overproduction prior to cell division causes cell size to increase gradually with age. The rate of cell size increase with age is linked to the rate of protein production, which is dependent on the type of nutrients the cell grows on. We conclude that our microfluidic device is an excellent tool to study yeast aging and metabolism at the single cell level