报告题目：The yin and yang properties of extracellular DNA in biofilms and sites of infection
报 告 人：Shawn Lewenza, Athabasca University, Associate Professor，University of Calgary, Adjunct Associate Professor
联 系 人：许平 firstname.lastname@example.org
Extracellular DNA accumulates in the matrix of biofilms and at sites of infection. It is ubiquitous in all biofilms and plays a role in aggregation and attachment of biofilms. We have shown that DNA can sequester divalent cations, as well as acidify biofilms, which has important implications on long-term survival phenotypes ofPseudomonas aeruginosa. The accumulation of biofilm eDNA induces the expression of surface modifications that contribute to antimicrobial peptide and aminoglycoside resistance. DNA-induced genes also contribute to aggregation, virulence, acid pH tolerance, metal homeostasis and nutrient utilization. The cation chelating activity is required for a contact-mediated, fast acting, antimicrobial activity of DNA. DNA accumulates at many infection sites in the form of neutrophil extracellular traps (NET). Chromatin DNA forms the lattice structure of the NET, which is embedded with many antimicrobial vacuole components. We have recently shown that DNA is also an antimicrobial component of NETs. The DNA in the NET structure can be neutralized, and blocks NET killing. The accumulation of DNA is not just an inert extracellular polymer, rather it shapes the environment and has a wide range of effects on bacterial physiology. Using our knowledge of biofilms, we have explored new antibiofilm approaches to disrupt biofilm formation.