title: Determination of yeast viability during a stress-model alcoholic fermentation using reagent-free microscopy image analysis.
abstract: A dedicated microscopy imaging system including automated positioning, focusing, image acquisition, and image analysis was developed to characterize a yeast population with regard to cell morphology. This method was used to monitor a stress-model alcoholic fermentation with Saccharomyces cerevisiae. Combination of dark field and epifluorescence microscopy after propidium iodide staining for membrane integrity showed that cell death went along with important changes in cell morphology, with a cell shrinking, the onset of inhomogeneities in the cytoplasm, and a detachment of the plasma membrane from the cell wall. These modifications were significant enough to enable a trained human operator to make the difference between dead and viable cells. Accordingly, a multivariate data analysis using an artificial neural network was achieved to build a predictive model to infer viability at single-cell level automatically from microscopy images without any staining. Applying this method to in situ microscope images could help to detect abnormal situations during a fermentation course and to prevent cell death by applying adapted corrective actions.
authors.affiliation: Unité Mixte de Recherche Ingénierie des Agropolymères et Technologies Emergentes (UMR IATE), Université Montpellier 2, PlaceEugène Bataillon, CC023, 34095 Montpellier Cedex 05, France. pierretibayrenc@yahoo.fr
authors.forename: Pierre
authors.initials: P
authors.lastname: Tibayrenc
authors.forename: Charles
authors.initials: C
authors.lastname: Ghommidh
authors.forename: Laurence
authors.initials: L
authors.lastname: Preziosi-Belloy
mesh_terms: D000438:Alcohols / Q000378:metabolism*; D005285:Fermentation; D006801:Humans; D050296:Microbial Viability; D008853:Microscopy / Q000295:instrumentation* / Q000379:methods; D008954:Models, Biological; D016571:Neural Networks, Computer; D011419:Propidium; D012441:Saccharomyces cerevisiae / Q000166:cytology*; D013194:Staining and Labeling
chemical_list: D000438:Alcohols; D011419:Propidium