Physiological and Biochemical Responses of Yarrowia lipolytica to Dehydration Induced by Air-Drying and Freezing

Abstract

Organisms that can withstand anhydrobiosis possess the unique ability to temporarily and reversibly suspend their metabolism for the periods when they live in a dehydrated state. However, the mechanisms underlying the cell’s ability to tolerate dehydration are far from being fully understood. The objective of this study was to highlight, for the first time, the cellular damage to Yarrowia lipolytica as a result of dehydration induced by drying/rehydration and freezing/thawing. Cellular response was evaluated through cell cultivability determined by plate counts, esterase activity and membrane integrity assessed by flow cytometry, and the biochemical composition of cells as determined by FT-IR spectroscopy. The effects of the harvesting time (in the log or stationary phase) and of the addition of a protective molecule, trehalose, were investigated. All freshly harvested cells exhibited esterase activity and no alteration of membrane integrity. Cells freshly harvested in the stationary phase presented spectral contributions suggesting lower nucleic acid content and thicker cell walls, as well as longer lipid chains than cells harvested in the log phase. Moreover, it was found that drying/rehydration induced cell plasma membrane permeabilization, loss of esterase activity with concomitant protein denaturation, wall damage and oxidation of nucleic acids. Plasma membrane permeabilization and loss of esterase activity could be reduced by harvesting in the stationary phase and/or with trehalose addition. Protein denaturation and wall damage could be reduced by harvesting in the stationary phase. In addition, it was shown that measurements of loss of membrane integrity and preservation of esterase activity were suitable indicators of loss and preservation of cultivability, respectively. Conversely, no clear effect of freezing/thawing could be observed, probably because of the favorable operating conditions applied. These results give insights into Y. lipolytica mechanisms of cellular response to dehydration and provide a basis to better understand its ability to tolerate anhydrobiosis.

Room temperature deep eutectic solvents of (1S)-(+)-10-camphorsulfonic acid and sulfobetaines: hydrogen bond-based mixtures with low ionicity and structure-dependent toxicity

“…Many 95,97,98 It has been reported that an increase in the number of b-sheets in the cell proteins and in the number of strands in the b-sheets, is linked to protein denaturation, 98 as expected by proteins undergoing a fast dehydration. 99 This was also observed with a negative peak, common to all DESs, detected at 1585 cm À1 , corresponding to the amino acids side chain vibration. 100 Another negative band was observed in the mixed region (W3) around 1400 cm À1 (C]O n sym of COO À ).…”

Highlighting Protective Effect of Encapsulation on Yeast Cell Response to Dehydration Using Synchrotron Infrared Microspectroscopy at the Single-Cell Level

“…However, during this process, cells are subjected to several stresses such as mechanical, hydric, thermal and oxidative stresses, and inducing cell death ( Beker and Rapoport, 1987 ; Fu and Chen, 2011 ). Many previous studies have identified the plasma membrane as one of the main targets of cell injury associated to hydric disturbance in cell environment ( Guyot et al, 2006 ; Simonin et al, 2007 ; Dupont et al, 2011 ; Penicaud et al, 2014 ; Câmara et al, 2019 ). In particular, in our previous study ( Nguyen et al, 2017 ), synchrotron infrared spectroscopy revealed biochemical modifications during dehydration/rehydration processes of S. cerevisiae related to membrane fluidity.…”

Preservation of non‐Saccharomyces yeasts: Current technologies and challenges

“…A wide variety of dyes can be used, generally differing in their ability to stain live or dead cells. In the first case, color or fluorescence is usually associated with some reaction that takes place inside the cell, for example, esterase activity hydrolyses carboxy‐fluorescein di‐acetate, which results in increased fluorescence (Deere et al., 1998; Gabier et al., 2005; Penicaud et al., 2014). Dead cells can be stained using dyes that cannot cross an intact membrane or that are so small that, if they pass the membrane by diffusion, they are constantly eliminated in living cells (Alves‐Araujo et al., 2004; Deere et al., 1998; Khroustalyova & Rapoport, 2019; Redón et al., 2008).…”