Nowadays mass spectrometry is a powerful tool used to study, by a proteomic approach, the protein content and its function in different biological systems. Our investigations concern the study of cell proteins, in both animal and plant kingdom, that could be over- or under-expressed upon stress conditions or after chemical and therapeutic treatments 1. Plant systems 1.1 Proteomic of plants, algae and cyanobacteria under environmental stress conditions Proteomic mapping of the photosynthetic apparatus from plants, algae and cyanobacteria allows us to check if any change in the environmental conditions can result as a consequence of the adaptation. Thus, comparing untreated organism with one grown in stress conditions (water stress, light stress, heavy metals stress, temperature stress) it is possible to identify which are the main proteins involved and how the organism could be genetically modified; this gives the opportunity to obtain resistant organisms, hence to improve the productivity of determined crops. 1.2 Proteomic of genetically modified organisms (GMO): Three Zea mays lines (MON-810, Bt11, Bt176) have been developed by specific genetic modifications to become resistant to European corn borer (ECB): Ostrinia nubilalis. In this case the main aim of the research is to identify which are the changes of protein expression due to new gene insertion. 2 Animal systems 2.1 Proteomic of different pancreatic tumoral cell strains after drug treatment Pancreatic tumoral cell strains have been treated (separately or in combination) with drugs acting on the tumor epigenetic events (e.g. histone deacetylation, DNA hypermethylation). The proteomic analysis is focused on the identification of differential expressed proteins after drugs treatment. The study of activation/repression levels of the involved proteins results in an increased knowledge of growth processes and cell apoptotic response. 2.2 Proteomic of erythrocytes membranes and cell aging These studies are focused on the characterization of proteic pattern changes following the oxidative events due to cell aging during the common blood storage. 2.3 Proteomic of mammary glands of different cows The aim of this differential proteomic is the identification of specific proteins that could be potentially responsible of the biodiversity of cow races used for milk production.