title: A rapid method for the differentiation of yeast cells grown under carbon and nitrogen-limited conditions by means of partial least squares discriminant analysis employing infrared micro-spectroscopic data of entire yeast cells.
abstract: This paper shows the ease of application and usefulness of mid-IR measurements for the investigation of orthogonal cell states on the example of the analysis of Pichia pastoris cells. A rapid method for the discrimination of entire yeast cells grown under carbon and nitrogen-limited conditions based on the direct acquisition of mid-IR spectra and partial least squares discriminant analysis (PLS-DA) is described. The obtained PLS-DA model was extensively validated employing two different validation strategies: (i) statistical validation employing a method based on permutation testing and (ii) external validation splitting the available data into two independent sub-sets. The Variable Importance in Projection scores of the PLS-DA model provided deeper insight into the differences between the two investigated states. Hence, we demonstrate the feasibility of a method which uses IR spectra from intact cells that may be employed in a second step as an in-line tool in process development and process control along Quality by Design principles.
authors.affiliation: Department of Analytical Chemistry, University of Valencia, Edifici Jeroni Muñoz, 50th Dr. Moliner, E-46100 Burjassot, Spain.
authors.forename: Julia
authors.initials: J
authors.lastname: Kuligowski
authors.forename: Guillermo
authors.initials: G
authors.lastname: Quintás
authors.forename: Christoph
authors.initials: C
authors.lastname: Herwig
authors.forename: Bernhard
authors.initials: B
authors.lastname: Lendl
mesh_terms: D002244:Carbon / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D003470:Culture Media / Q000737:chemistry; D016002:Discriminant Analysis; D005240:Feasibility Studies; D016018:Least-Squares Analysis; D009584:Nitrogen / Q000494:pharmacology*; D010843:Pichia / Q000166:cytology* / Q000187:drug effects*; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013997:Time Factors
chemical_list: D003470:Culture Media; D002244:Carbon; D009584:Nitrogen