UNIVERSITE DE BOURGOGNE - Université de Bourgogne
UNIVERSITE DE BOURGOGNE - Université de Bourgogne
UNIVERSITE DE BOURGOGNE - Université de Bourgogne
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Title:<br />
Physiologic and biologic mechanisms induced in Yarrowia lipolytica in response to<br />
physico-chemical modifications of cells environment.<br />
Abstract:<br />
Hydrophobic compounds are known as carbon sources which can be used by yeast like<br />
Yarrowia lipolytica for multi purposes. These compounds may cause disturbance in yeast but<br />
has also been shown as confering some resistance to cells towards environmental stress. Here,<br />
we study the role of methyl oleate as the carbon source on the resistance of Y. lipolytica in<br />
response to the stress caused by an amphiphilic compound, γ-do<strong>de</strong>calactone, and to heat<br />
shock. Results show that cells grown in oleate are more resistant to these stresses than cells<br />
grown in glucose. This work reveals the role of lipid bodies in cell response to stress and that<br />
cells manifest in different ways in response to these stresses. An accumulation of lipid bodies<br />
is required for the resistance of cells towards stress as glucose grown cells transform their free<br />
sterol into steryl esters to form lipid bodies in response to the lactone shock which increases<br />
their sensitivity towards lactone. In the case of oleate grown cells which accumulated lipid<br />
bodies during their growth, cells tend to convert their steryl esters into free sterol in or<strong>de</strong>r to<br />
compensate sterol <strong>de</strong>pletion caused by the lactone shock and <strong>de</strong>crease their sensitivity.<br />
Homeostasis of ergosterol, linked with the presence of lipid bodies, seems to be a key for<br />
mechanism of cellular resistance to stresses. This work reveals also that the presence of lipid<br />
bodies modifies the processes of programmed cells <strong>de</strong>ath in response to heat shock.<br />
Key words: Yarrowia lipolytica, oleate, lipid bodies, lactone, heat, stress<br />
4