DEVELOPING AN INTEGRATED OMICS TECHNOLOGY TO ELUCIDATE BIOLOGICAL MECHANIISM OF METAL EXPOSURE
Creators: name: Galano, Eugenio
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2013

description: About 30% of all annotated proteins reported in the major databases (PDB, NCBInr,and Uniprot) results to be associated with a metal. In some cases the functions of these proteins strongly depend by the interaction with the right metal.
Metal ions, associated with macromolecules, are utilized by biological systems in fundamental processes; therefore cytosolic concentrations of metals are tightly
controlled. For a complete characterization of cell chemistry, the understanding of mechanisms by which a metal is sensed, stored, or incorporated as a cofactor is required.
Some metals, such as Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni and Zn, are essential,in fact they serve as micronutrients and are used for redox-processes, to stabilize molecules through electrostatic interactions, as components of various enzymes and for regulation of osmotic pressure. Many other metals, in particular heavy metals, have no biological role (e.g. Ag, Al, Cd, Au, Pb and Hg), and are nonessential and
potentially toxic to mammalians and microorganisms.
Selenium is a crucial micronutrient for human health. In human Se is a component of several important selenoproteins and enzymes required for different functions, such as antioxidant defense and reduction of inflammation. Several organisms possess the ability to metabolize Se into protein by a specific pathway dedicated to the biosynthesis of proteins which contain the aminoacid selenocysteine (Sec, U), or by a non-specific mechanism.
The improvements in high-throughput technology, has led to born of a large number
of new “omics” disciplines with the aim to expand the knowledge acquired. Thus
“metallomics” was born; this term, coined by Haraguchi, denotes the ensemble of research activities related to metals of biological interest.
However detailed knowledge of interaction between metals and proteins within organisms is fundamental to prevent diseases related to heavy metals pollutions, or to use some detoxification process to produce more bio-available forms of selenocontaining compounds.
This PhD thesis targeted the characterization of metals involved in relevant biological processes by metallomics and proteomics approaches. Thus the following systems of biotechnological interest have been analyzed in this study: 1) Escherichia coli used as model organism for a study of the effects of heavy-metals contamination. The development of an integrated metallomics-proteomics approach for the investigation of the effects of cadmium exposure on Escherichia coli is reported. 
2) HRCE (Human Renal Cortical Epithelial) cells for an investigation of the effects to cadmium and lead exposure. Apoptotic pathway was demonstrated to be induced by either cadmium or lead, with the latter the more toxic for human
primary renal cells. 
3) Lactobacillus reuteri Lb2 BM-DSM 16143 to study the
incorporation of selenium into selenocysteines by an integrated ICP-MS based approach. Characterization of the ability of this probiotic microorganism to recover high concentration of selenium and convert them into selenocysteines residues, within the primary sequence of some proteins, is reported, representing an additional
innovative approach to solve human selenium deficiency.