title: 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.
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Pénicaud
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Landaud
authors.affiliation: Synchrotron SOLEIL, Gif-sur-Yvette, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Jamme
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France.
authors.forename: Pauline
authors.initials: P
authors.lastname: Talbot
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France.
authors.forename: Marielle
authors.initials: M
authors.lastname: Bouix
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France.
authors.forename: Sarrah
authors.initials: S
authors.lastname: Ghorbal
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Fonseca
mesh_terms: D000388:Air; D002462:Cell Membrane / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D003681:Dehydration; D005434:Flow Cytometry; D005612:Freeze Drying; D018384:Oxidative Stress; D010539:Permeability; D010710:Phosphates / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014199:Trehalose / Q000737:chemistry; D025062:Yarrowia / Q000378:metabolism* / Q000502:physiology
chemical_list: D003470:Culture Media; D010710:Phosphates; D014199:Trehalose