title: Role of biofilm in protection of the replicative form of Legionella pneumophila.
abstract: The dual nature of Legionella pneumophila enables its survival in free and intracellular environments and underpins its infection and spread mechanisms. Experiments using bacterial cultures and improved RTqPCR protocols were devised to gain fresh insights into the role of biofilm in protecting the replicative form of L. pneumophila. mip gene expression was used as a marker of virulence in sessile (biofilm-bound) and planktonic (free-floating) cells of L. pneumophila serotype 1 ATCC 33152. The ratio of mip gene expression to transcriptionally active Legionella cells increased both in sessile and free-floating cells demonstrating an up-regulation of mip gene under nutrient depletion. However, a different trend was observed between the two forms, in planktonic cells the mip gene expression/transcriptionally active Legionella cells increased until the end of the experiment, while in the biofilm such increase was observed at the end of the experiment. These findings suggest a possible association between the switch to the transmissive phase of Legionella and a mip up-regulation and a role for biofilm in preserving Legionella cells in replicative form. Moreover, it has been shown that improved RTqPCR protocols are valuable tools to explore bacterial virulence.
authors.affiliation: Department of Biomolecular Sciences, Section of Toxicological, Hygienistic and Environmental Sciences, University of Urbino "Carlo Bo", Urbino, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Andreozzi
authors.forename: Andrea
authors.initials: A
authors.lastname: Di Cesare
authors.forename: Luigia
authors.initials: L
authors.lastname: Sabatini
authors.forename: Elisa
authors.initials: E
authors.lastname: Chessa
authors.forename: Davide
authors.initials: D
authors.lastname: Sisti
authors.forename: Marco
authors.initials: M
authors.lastname: Rocchi
authors.forename: Barbara
authors.initials: B
authors.lastname: Citterio
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D016952:Legionella pneumophila / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D050296:Microbial Viability; D019696:Peptidylprolyl Isomerase / Q000032:analysis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; C512922:Mip protein, Legionella pneumophila; D019696:Peptidylprolyl Isomerase