Differences in stationary-phase cells of a commercial Saccharomyces cerevisiae wine yeast grown in aerobic and microaerophilic batch cultures assessed by electric particle analysis, light diffraction and flow cytometry

Abstract

We applied electric particle analysis, light diffraction and flow cytometry to obtain information on the morphological changes during the stationary phase of Saccharomyces cerevisiae. The reported analyses of S. cerevisiae populations were obtained under two different conditions, aerobic and microaerophilic, at 27°C. The samples analysed were taken at between 20 and 50 h from the beginning of culture. To assist in the interpretation of the observed distributions a complexity index was used. The aerobically grown culture reached significantly greater cell density. Under these conditions, the cell density experienced a much lower reduction (3%) compared with the microaerophilic conditions (30%). Under aerobic conditions, the mean cell size determined by both electric particle analysis and light diffraction was lower and remained similar throughout the experiment. Under microaerophilic conditions, the mean cell size determined by electric particle analysis decreased slightly as the culture progressed through the stationary phase. Forward and side scatter distributions revealed two cell subpopulations under both growth conditions. However, in the aerobic growing culture the two subpopulations were more separated and hence easier to distinguish. The distributions obtained with the three experimental techniques were analysed using the complexity index. This analysis suggested that a complexity index is a good descriptor of the changes that take place in a yeast population in the stationary phase, and that it aids in the discussion and understanding of the implications of these distributions obtained by these experimental techniques.

Modelización del crecimiento de una población microbiana en medio líquido y su implicación en el estudio de la morfología celular a través del análisis digital de imágenes

“…En ellos, las condiciones del entorno varían y Saccharomyces debe adaptarse a los cambios ambientales viéndose obligada a pasar en poco tiempo de condiciones aerobias a microaerófilas y a anaerobias, cambiando el tipo de metabolismo en relación a la concentración de oxígeno presente. Comprender su crecimiento respirofermentativo es importante para optimizar los diferentes procesos biotecnológicos en los que esta levadura está implicada (Portell, Ginovart, Carbó & Vives-Rego, 2011;Carbó et al, 2015).…”

Digital Image Analysis of Yeast Single Cells Growing in Two Different Oxygen Concentrations to Analyze the Population Growth and to Assist Individual-Based Modeling

“…In addition, the morphology of the cells is closely related to their physiological state and their status in the cell cycle (Coelho et al, 2004 ). The relevance of cell size measurements to study the response of yeast cells submitted to various stresses has also been shown (Tibayrenc et al, 2010 ; Portell et al, 2011 ).…”

Weighting order and disorder on complexity measures

“…Both measures combine equilibrium (disorder) and disequilibrium (order) parameters resulting in expressions for complexity. Several problems were successfully studied with this approach as, for instance, in Biology [11,12] and Meteorology [13], but with criticism concerning the same weight to order and disorder.…”