Project title
The authors acknowledge financial support from the Portuguese Foundation for Science and Technology (research Grants PTDC/EEB-BIO/99810/2008 and PTDC/SAUMET/ 111398/2009). The NMR spectrometers are part of the National NMR Network and were purchased in the framework of the National Programme for Scientific Reequipment, Contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and the Portuguese Foundation for Science and Technology.