The role of individual exopolysaccharides in antibiotic tolerance of Pseudomonas aeruginosa aggregates

The bacterium Pseudomonas aeruginosa is involved in chronic infections of cystic fibrosis lungs and chronic wounds. In these infections the bacteria are present as aggregates suspended in host secretions. During the course of the infections there is a selection for mutants that overproduce exopolysaccharides, suggesting that the exopolysaccharides play a role in the persistence and antibiotic tolerance of the aggregated bacteria. Here, we investigated the role of individual P. aeruginosa exopolysaccharides in aggregate-associated antibiotic tolerance. We employed an aggregate-based antibiotic tolerance assay on a set of P. aeruginosa strains that were genetically engineered to over-produce a single, none, or all of the three exopolysaccharides Pel, Psl, and alginate. The antibiotic tolerance assays were conducted with the clinically relevant antibiotics tobramycin, ciprofloxacin and meropenem. Our study suggests that alginate plays a role in the tolerance of P. aeruginosa aggregates toward tobramycin and meropenem, but not ciprofloxacin. However, contrary to previous studies we did not observe a role for Psl or Pel in the tolerance of P. aeruginosa aggregates toward tobramycin, ciprofloxacin, and meropenem

WINDNA:eDNA based solutions for biodiversity monitoring at offshore wind farms

The transition towards renewable energy may have substantial impact on marine ecosystems in the near future. Wind energy is planned to expand by a factor 10 in the North Sea region alone by 2050. The ambitious political objectives seek to shift from a "no net loss" (NNL) to a "marine net gain" (MNG) approach when licensing projects. Hence, there is a pressing need to document the impact of offshore wind on marine biodiversity. However, traditional methods are costly, labor-intensive, and lack both taxonomic and spatio-temporal resolution. The "WINDNA" project will evaluate the potential of environmental DNA (eDNA) and aim to provide new cost-effective and comprehensive marine biodiversity data. Key aspects involve examining the spatial and temporal scales of marine biodiversity using traditional water sampling by boat as well as an offshore-deployed automated environmental sample processor and an autonomous underwater vehicle (ESP2 and ESP3). Furthermore, "WINDNA" focuses on monitoring biodiversity changes during the early stages of artificial reef succession. The "WINDNA" project provides a pragmatic approach, aligning with environmental and political goals contributing to the sustainable growth of renewable energy while prioritizing positive biodiversity impact. The presentation will include preliminary data