Aging is an inevitable life process that every living organism must undergo. Different studies demonstrated the "free radicals theory" that correlates reactive oxygen species production and aging. To explore this issue in eukaryotic cells, we studied the antioxidant system of the ciliated protozoan T. thermophila. One of the most important characteristics of this model organism is his "immortality", being able to multiply indefinitely by binary fission. The objective of our research is to study the antioxidant system in the different phases (juvenility, maturity and senescence) of T. thermophila life cycle and to analyze the effect of various oxidative stress conditions (exposure to UV, peroxides and metals). With this aim we have firstly characterized the molecular properties of some antioxidant enzymes.

Total RNA has been extracted from T. thermophila cells maintained in normal growth conditions for three days. cDNA sequences were obtained by RT-PCR, 3'- and 5'-RACE techniques. The primers for the amplification of Cu,Zn-SOD, Mn-SOD and catalase cDNAs were designed after a cross analysis between NCBI and T. thermophila genome databases.

We have cloned and sequenced the cDNA of two Cu,Zn-SOD isoforms, one Mn-SOD, and one catalase. The results demonstrated that these genes were constitutively expressed. The primers employed for the PCR-amplifications will be used for RT-qPCR gene expression studies in different experimental conditions.

(Supported by M.I.U.R. grants)