High nitrogen concentration causes G2/M arrest in Hanseniaspora vineae

Area of Science:

• Microbiology
• Cell Biology
• Biochemistry

Background:

• Yeasts are crucial models for cell cycle research.
• Nitrogen scarcity's effects on cell cycle are known, but nitrogen excess is understudied.
• Hanseniaspora vineae shows impaired entry into quiescence, potentially linked to nitrogen availability.

Purpose of the Study:

• Investigate the impact of varying nitrogen concentrations on H. vineae cell cycle progression.
• Elucidate the mechanism behind the absence of proper quiescent state entry in H. vineae under nitrogen excess.

Main Methods:

• Culturing H. vineae under different nitrogen concentrations.
• Monitoring cell cycle progression using flow cytometry.
• Assessing cell viability, reactive oxygen species (ROS) production, mitochondrial membrane potential, intracellular pH, and DNA fragmentation.

Main Results:

• Nitrogen excess, irrespective of the source, disrupts cell cycle progression and induces G2/M arrest in H. vineae.
• Cell viability declined in an ammonium-dependent manner.
• Increased ROS production, mitochondrial hyperpolarization, intracellular acidification, and DNA fragmentation were observed.

Conclusions:

• Nitrogen excess triggers cell cycle arrest at G2/M phase in H. vineae.
• The study elucidates potential mechanisms for impaired quiescence entry, involving oxidative stress and cellular damage.
• Findings highlight the critical role of nitrogen availability in regulating yeast cell cycle dynamics.