Libro de Resúmenes / Book of Abstracts (Español/English)
Libro de Resúmenes / Book of Abstracts (Español/English)
Libro de Resúmenes / Book of Abstracts (Español/English)
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Resumenes 152<br />
Inhibition effects <strong>of</strong> inorganic and organic compounds on<br />
Saccharomyces cerevisiae metabolism: NMR and mathematical<br />
mo<strong>de</strong>lling studies<br />
Claudio Rossi # , Annalisa Santucci°, Fiora Bartolini # , Maso Ricci # ,<br />
Silvia Martini # , Claudia Bonechi #<br />
# Department <strong>of</strong> Chemical and Biosystem Sciences - University <strong>of</strong> Siena<br />
Via Aldo Moro, 2 53100 Siena, Italy<br />
°Department <strong>of</strong> Molecular Biology - University <strong>of</strong> Siena<br />
Via Fiorentina, 1 – 53100 Siena, Italy<br />
In vivo NMR spectroscopy, together with the use <strong>of</strong> 13 C labelled<br />
substrates, is an elective tool to investigate metabolic processes occurring<br />
in complex systems such as cellular cultures. Because <strong>of</strong> its “non invasive”<br />
nature, NMR spectroscopy can be useful in kinetic studies in which several<br />
samplings are required during metabolic activity. In fact, selective enriched<br />
substrates allow the mapping <strong>of</strong> the fate <strong>of</strong> the metabolite during the<br />
fermentation process.<br />
In this work, an approach based on in vivo 13 C NMR and mathematical<br />
mo<strong>de</strong>lling was presented in or<strong>de</strong>r to <strong>de</strong>velop a basis for a <strong>de</strong>eper<br />
un<strong>de</strong>rstanding <strong>of</strong> eukaryotic responses to environmental stresses. The<br />
mo<strong>de</strong>l consi<strong>de</strong>rs three distinct compartments interacting each other: the<br />
carbon source, the main end product and the yeast cells. A set <strong>of</strong> non-linear<br />
differential equations was <strong>de</strong>veloped to <strong>de</strong>scribe the time evolution <strong>of</strong><br />
glucose and ethanol concentrations and the number <strong>of</strong> active yeast cells.<br />
The kinetic constants in each equation were optimised by a non-linear leastsquare<br />
fitting procedure (Marquardt-Levenberg) representing the kinetic<br />
constants associated to <strong>de</strong>gradation <strong>of</strong> glucose (kD), production <strong>of</strong> ethanol<br />
(kP) and inhibition <strong>of</strong> active cells (kI). These constants, having a biological<br />
meaning, have been used in or<strong>de</strong>r to un<strong>de</strong>rstand and <strong>de</strong>scribe the response<br />
<strong>of</strong> Saccharomices cerevisiae to external stimuli (such as exogenous<br />
ethanol). The kP/kD ratio has been found to simulate correctly the yield <strong>of</strong><br />
the fermentation process, allowing the prediction <strong>of</strong> the effects <strong>of</strong> external<br />
stress to metabolic activity <strong>of</strong> the yeast.<br />
Referencias<br />
[1] M. Ricci, S. Martini, C. Bonechi, A. Santucci, L. Trabalzini, C. Rossi:<br />
“Inhibition Effects <strong>of</strong> Ethanol on the Kinetics <strong>of</strong> Glucose Metabolism by<br />
S. Cerevisiae: NMR and Mo<strong>de</strong>lling Study”, Chemical Physics Letters, 387<br />
(4-6), 377-382,2004.<br />
[2] S. Martini, M. Ricci, C. Bonechi, L. Trabalzini, A. Santucci, C. Rossi: “In<br />
Vivo 13C-NMR and Mo<strong>de</strong>lling Study <strong>of</strong> Metabolic Yield Response to<br />
Ethanol Stress in a Wild-Type Strain <strong>of</strong> Saccharomyces cerevisiae”.<br />
FEBS Letters 564, 63-68, 2004.<br />
[3] S. Bastianoni, C. Bonechi, A. Gastal<strong>de</strong>lli, S. Martini and C. Rossi:<br />
“Mo<strong>de</strong>lling interpretation <strong>of</strong> kinetics <strong>of</strong> metabolic processes”. In:<br />
“Chemistry at the Beginning <strong>of</strong> the third Millennium”, Fabbrizzi L: and<br />
Poggi A., Eds, Springer and Verlag (2000) pp 305-328.