BY4741 cannot enter quiescence from rich medium

Area of Science:

• Cell Biology
• Microbiology
• Biochemistry

Background:

• * Saccharomyces cerevisiae* is a model organism for studying cell cycle regulation and nutrient sensing.
• * Glucose availability is a primary driver of yeast growth and proliferation.
• * Quiescence is a reversible cell cycle arrest state crucial for survival under nutrient limitation.

Purpose of the Study:

• * To compare the cell cycle progression and quiescence entry of two *Saccharomyces cerevisiae* strains (W303 and BY4741) in rich medium.
• * To investigate the relationship between glucose availability, biomass accumulation, and cell cycle arrest.
• * To determine if BY4741 exhibits stereotypical quiescence entry mechanisms observed in other strains.

Main Methods:

• * Culturing *Saccharomyces cerevisiae* strains W303 and BY4741 in rich medium.
• * Monitoring cell density and cell cycle phase distribution over time.
• * Measuring glucose concentration and correlating it with cell division and arrest points.

Main Results:

• * W303 cells entered G1 arrest approximately one hour before glucose exhaustion, after one asymmetrical cell division.
• * BY4741 cells arrested cell division four hours before glucose exhaustion at a significantly lower cell density.
• * BY4741 cells did not undergo asymmetrical division, and only 50% arrested in G1, suggesting non-glucose-limited growth.

Conclusions:

• * Yeast strain BY4741's growth is not solely limited by glucose and it deviates from typical quiescence entry pathways.
• * In W303, glucose limitation and quiescence entry are closely linked to biomass accumulation rate and cell doubling time.
• * Strain-specific differences in *Saccharomyces cerevisiae* dictate responses to nutrient availability and cell cycle regulation.