The Operative Unit address fundamental questions in the field of microbiology using advanced biotechnological techniques. The Unit carries on the following research topics: • Investigating the interaction between Neisseria meningitidis and the respiratory epithelial barrier in in vitro cell and in vivo (mouse) infection models for development of new therapies and vaccine implementation. The human nasopharynx is the portal of entry of Neisseria meningitidis to spread across the respiratory epithelium and enter the systemic circulation before crossing the blood–brain barrier causing fatal sepsis and meningitis. • Integrating genome mining, systems biology and metabolic engineering for new drug discovery and strain improvement of Actinomycetes, a group of bacteria producing over 70% of naturally occurring antibiotics and other biologically active substances including anti-tumour agents and immunosuppressants. As wild type strains produce only limited amounts of compounds, genetic manipulation is required before they can be used for production. The knowledge on the biosynthetic pathways and genetic control for several secondary metabolites help strain improvement by DNA recombinant technologies. • Genetic control, ecological role and mathematical modeling of quorum sensing in luminescent Vibrio spp. Quorum sensing is the mechanism by which bacteria are able to “sense” their environment. Besides bioluminescence, these actions involve the expression of genes that control biofilm development, virulence and several other traits. • Microbial volatile organic compounds as signaling molecules in microbe-insect-plant interactions. Volatile organic compounds produced by microoganisms (MVOC) living in insects and plants regulate insect-insect and insect-plant ecological interactions. Identifying and characterizing the microorganisms producing MVOCs is important to exploit, in the future, their use as possible alternatives to harmful pesticides, fungicides and bactericides.