RT Journal Article
SR Electronic
T1 The structural role of bacterial eDNA in the formation of biofilm streamers
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.07.26.453754
DO 10.1101/2021.07.26.453754
A1 Eleonora Secchi
A1 Giovanni Savorana
A1 Alessandra Vitale
A1 Leo Eberl
A1 Roman Stocker
A1 Roberto Rusconi
YR 2021
UL http://biorxiv.org/content/early/2021/07/26/2021.07.26.453754.abstract
AB Across diverse habitats, bacteria are mainly found as biofilms, surface-attached communities embedded in a self-secreted matrix of extracellular polymeric substances (EPS), which enhances bacterial resistance to antimicrobial treatment and mechanical stresses. In the presence of flow and geometric constraints such as corners or constrictions, biofilms take the form of long, suspended threads known as streamers, which bear important consequences in industrial and clinical settings by causing clogging and fouling. The formation of streamers is thought to be driven by the viscoelastic nature of the biofilm matrix. Yet, little is known about the structural composition of streamers and how it affects their mechanical properties. Here, using a microfluidic platform that allows growing and precisely examining biofilm streamers, we show that extracellular DNA (eDNA) constitutes the backbone and is essential for the mechanical stability of Pseudomonas aeruginosa’ s streamers. This finding is supported by the observations that DNA-degrading enzymes prevent the formation of streamers and clear already formed ones, and that the antibiotic ciprofloxacin promotes their formation by increasing the release of eDNA. Furthermore, using mutants for production of the exopolysaccharide Pel, an important component of P. aeruginosa’ s EPS, we reveal a new, although indirect role of Pel, in tuning the mechanical properties of the streamers. Taken together, these results highlight the importance of eDNA and of its interplay with Pel in determining the mechanical properties of P. aeruginosa streamers, and suggest that targeting the composition of streamers can be an effective approach to control the formation of these biofilm structures.Competing Interest StatementThe authors have declared no competing interest.