We are also interested in the study of the stability and conservation of RNA molecules. We have shown that high salt (Na) concentration plays a protective role in tRNA against thermal degradation allowing activity to be restored (Tehei et al, 2002). We selected thermo-halophilic aptamers in vitro that were resistant to degradation at 85°C in the presence of high salt for 65 h. The clones recovered were regrouped into two families (Family I and Family II) that each possesses its own physico-chemical characeristics as well as a secondary structure similar to that of numerous viroids.These two families correspond to two pathways leading to thermo-resistance.
The molecular behavior thus highlighted allows us to define the survival limits in primitive (and/or extreme) conditions, and demonstrate that what is at stake for RNA molecules as also for the organisms during the course of evolution, is reproductive capacity (Vergne et al, 2006). Finally, we have characterized the behavior of ASBVd at high temperature in conditions close to that of hydrothermalism (El Murr et al, 2012).
We have also developed a method to detect nucleic acids by SERS Raman spectrometry (Elamri et al, 2003, 2004, 2005) that allows us to detect nanomoles of oligonucleotides by selectively sounding constitutive adenyl residues. This method was used to study the kinetics of auto-cleavage of sub-nanomoles of ribozymes in solution (Percot et al, 2009).