Ανδρέας Ρούσσης, Επίκουρος Καθηγητής, Βιολογίας, ΕΚΠΑ
Oxidative stress is one of the main causes of stress of photosynthetic organisms
and can lead to significant environmental and economic impacts. SBP is a highly
conserved protein, essential for organisms at low concentrations and at the same time
toxic to larger ones. Its exact biological role has not yet been fully elucidated. The aim
of the present project is to study the effect of oxidative stress on the microalgae- model
Chlamydomonas reinhardtii with a parallel search for possible involvement of SBP in
To achieve this aim cultivations of both wild type strain and a mutant strain,
knock-out for the gene encoding SBP, were grown. The cultures were exposed to
concentrations of 0 mM, 2 mM, 5 mM and 7 mM H2 O2 for 0, 1, 6 and 12 hours.
Determination of growth rate and survival rate of cells was performed, followed by
measurement of the total oxidative potential of cultures using the FRAP method. To
study the relative levels of gene expression of genes associated with oxidative stress
and genes interacting with SBP, RT-qPCR analysis was performed. Finally, the
metabolic profile of the cells exposed to each treatment was determined by gas
chromatography - mass spectrometry (GC-MS).
The presence of superoxide has been shown to affect the survival of the two
strains differently, with the mutant displaying higher survival rates. Differences exist
in the total oxidative potential of the two strains in a manner dependent on the
manipulations to which they were exposed each time. The RT-qPCR method showed
that the relative expression levels of genes that interact with SBP increase in the mutant
strain. Lastly, with the GC-MS analysis, 164 different metabolites produced by C.
reinhardtii were identified as well as the metabolic profile it develops when exposed to
microalgae, oxidative stress, C. reinhardtii, SBP