TY - JOUR
T1 - Metabolomic analysis of the green microalga Chlamydomonas reinhardtii cultivated under day/night conditions
AU - Willamme, Rémi
AU - Alsafra, Zouheir
AU - Arumugam, Rameshkumar
AU - Eppe, Gauthier
AU - Remacle, Françoise
AU - Levine, R. D.
AU - Remacle, Claire
N1 - Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/12/10
Y1 - 2015/12/10
N2 - Biomass composition of Chlamydomonas reinhardtii was studied during two consecutive cycles of 12 h light/12. h dark. As in our experimental conditions the two synchronized divisions were separated by 20 h, it was possible to show that accumulation of dry weight, proteins, chlorophyll and fatty acids mainly depends on cell division, whereas starch accumulation depends on a circadian rhythm as reported previously. Our metabolomics analyses also revealed that accumulation of five (Ser, Val, Leu, Ile and Thr) of the nine free amino acids detected displayed rhythmicity, depending on cell division while Glu was 20-50 times more abundant than the other ones probably because this free amino acid serves not only for protein synthesis but also for biosynthesis of nitrogen compounds. In addition, we performed a thermodynamic-motivated theoretical approach known as 'surprisal analysis'. The results from this analysis showed that cells were close to a steady state all along the 48 h of the experiment. In addition, calculation of free energy of cellular metabolites showed that the transition point, i.e. the state which immediately precedes cell division, corresponds to the most unstable stage of the cell cycle and that division is identified as the greatest drop in the free energy of metabolites.
AB - Biomass composition of Chlamydomonas reinhardtii was studied during two consecutive cycles of 12 h light/12. h dark. As in our experimental conditions the two synchronized divisions were separated by 20 h, it was possible to show that accumulation of dry weight, proteins, chlorophyll and fatty acids mainly depends on cell division, whereas starch accumulation depends on a circadian rhythm as reported previously. Our metabolomics analyses also revealed that accumulation of five (Ser, Val, Leu, Ile and Thr) of the nine free amino acids detected displayed rhythmicity, depending on cell division while Glu was 20-50 times more abundant than the other ones probably because this free amino acid serves not only for protein synthesis but also for biosynthesis of nitrogen compounds. In addition, we performed a thermodynamic-motivated theoretical approach known as 'surprisal analysis'. The results from this analysis showed that cells were close to a steady state all along the 48 h of the experiment. In addition, calculation of free energy of cellular metabolites showed that the transition point, i.e. the state which immediately precedes cell division, corresponds to the most unstable stage of the cell cycle and that division is identified as the greatest drop in the free energy of metabolites.
KW - Chlamydomonas
KW - Day/night cycle
KW - Metabolomics
KW - Surprisal analysis
UR - http://www.scopus.com/inward/record.url?scp=84947043826&partnerID=8YFLogxK
U2 - 10.1016/j.jbiotec.2015.04.013
DO - 10.1016/j.jbiotec.2015.04.013
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C2 - 25941156
AN - SCOPUS:84947043826
SN - 0168-1656
VL - 215
SP - 20
EP - 26
JO - Journal of Biotechnology
JF - Journal of Biotechnology
ER -