Project description:To characterize the taxonomic and functional diversity of biofilms on plastics in marine environments, plastic pellets (PE and PS, ø 3mm) and wooden pellets (as organic control) were incubated at three stations: at the Baltic Sea coast in Heiligendamm (coast), in a dead branch of the river Warnow in Warnemünde (inlet), and in the Warnow estuary (estuary). After two weeks of incubation, all pellets were frozen for subsequent metagenome sequencing and metaproteomic analysis. Biofilm communities in the samples were compared on multiple levels: a) between the two plastic materials, b) between the individual incubation sites, and c) between the plastic materials and the wooden control. Using a semiquantitative approach, we established metaproteome profiles, which reflect the dominant taxonomic groups as well as abundant metabolic functions in the respective samples.
Project description:Several environmental bacteria encode plastic-degrading enzymes, a potential evolutionary response to the rapid introduction of plastic across global ecosystems. Given the widespread use of plastic in healthcare, we hypothesised that clinical bacterial isolates may also degrade plastic, rendering plastic-containing medical devices susceptible to degradation and failure and potentially offering these pathogens a carbon source that could be used to persist in the hospital-built environment. Here, we mined the genomes of prevalent pathogens and identified several enzymes in different pathogens with homology to known plastic-degrading enzymes. Synthesising and expressing a potential plastic-degrading enzyme derived from a Pseudomonas aeruginosa wound isolate in a heterologous host, we were able to demonstrate potent plastic degrading activity. We subsequently found that the original P. aeruginosa clinical isolate could reduce the weight of a medically relevant plastic, polycaprolactone (PCL), by 78% in 7 days, and critically could use it as a sole carbon source to grow. We uncovered a direct link to virulence, demonstrating that encoding a plastic degrading enzyme can significantly enhance biofilm formation and pathogenicity in vivo. We also demonstrate that this augmented biofilm phenotype is conserved in another P. aeruginosa PCL-degrading clinical isolate we identified in a screening. We reveal that the mechanism underpinning this enhanced biofilm formation is the incorporation of the plastic breakdown products into the extracellular matrix, leading to enhanced biofilm levels. The level of PCL degradation we show by a clinical isolate and its ability to promote a key virulence and persistence determinant such as biofilm formation indicates that the integrity of any PCL containing medical device, such as sutures or implants, and the condition of patients receiving such devices could be severely compromised by pathogens with this capacity. Given the central role of plastic in healthcare, this should be considered in the future of medical interventions and practice and hospital designs implementing this material
Project description:Examining the impact of short term exposure to HDPE and PVC plastic leachates on gene transcription in Prochlorococcus cultures in vitro
