title: A high-throughput method for quantifying metabolically active yeast cells.
abstract: By redesigning the established methylene blue reduction test for bacteria and yeast, we present a cheap and efficient methodology for quantitative physiology of eukaryotic cells applicable for high-throughput systems. Validation of the method in fermenters and high-throughput systems proved equivalent, displaying reduction curves that interrelated directly with CFU counts. For growth rate estimation, the methylene blue reduction test (MBRT) proved superior, since the discriminatory nature of the method allowed for the quantification of metabolically active cells only, excluding dead cells. The drop in metabolic activity associated with the diauxic shift in yeast proved more pronounced for the MBRT-derived curve compared with OD curves, consistent with a dramatic shift in the ratio between live and dead cells at this metabolic event. This method provides a tool with numerous applications, e.g. characterizing the death phase of stationary phase cultures, or in drug screens with pathogenic yeasts.
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Subir Kumar
authors.initials: SK
authors.lastname: Nandy
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Peter Boldsen
authors.initials: PB
authors.lastname: Knudsen
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Alexander
authors.initials: A
authors.lastname: Rosenkjaer
authors.forename: Anna Eliasson
authors.initials: AE
authors.lastname: Lantz
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Jette
authors.initials: J
authors.lastname: Thykaer
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Mhairi
authors.initials: M
authors.lastname: Workman
mesh_terms: D004396:Coloring Agents / Q000737:chemistry; D005285:Fermentation; D057166:High-Throughput Screening Assays / Q000379:methods*; D007700:Kinetics; D008751:Methylene Blue / Q000737:chemistry; D050296:Microbial Viability; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013194:Staining and Labeling / Q000379:methods*
chemical_list: D004396:Coloring Agents; D008751:Methylene Blue
keywords: Saccharomyces cerevisiae; high throughput; metabolically active cells; methylene blue; quantification