Prokaryotic and eukaryotic expression systems for the production of recombinant proteins and nanoparticles for research and bio-industry

Living organisms can produce complex structures with specific functions for their metabolism that are used in a range of bio-industry and research activities. Biotechnology exploits prokaryotic and eukaryotic systems for expression of recombinant proteins, vaccines and antibodies as well as nano-structures. Indeed a number of nanoparticle-based products have been approved for diagnostics and therapeutics and more are currently under clinical trials. In this thesis work, the possibility of using different expression systems for the preparation of bio-products has been exploited. The first part of this thesis concerns the purification of magnetic nanoparticles called magnetosomes from Magnetospirillum.gryphiswaldense, a magnetotactic microaerophilic bacterium. Subsequently these nanoparticles have been tested as contrast agents in NMR analysis or as therapeutic agents for tumor thermotherapy. The chemical-physical properties of magnetosomes efficiently purified have been studied, confirming the goodness of these nanoparticles as contrast agents. Then magnetosomes has been tested in thermotherapy in vitro and in vivo against two cancer cell lines. In the second part of the thesis instead has been developed a system for the production of an important eukaryotic membrane protein, LHCSR, involved in the delicate process of regulation photoprotection in algae and mosses. In particular the protein LHCSR1 from the moss Physcomitrella patens has been efficiently expressed in two eukaryotic systems, Nicotiana benthamiana and Nicotiana tabacum realizing its isolation from thylakoid membrane and the preliminary determination of its biochemical and spectroscopic properties.