Ability of the marine bacterium Pseudomonas fluorescens BA3SM1 tocounteract the toxicity of CdSe nanoparticles

CdSe nanoparticles (CdSe NPs) are extensively used in the industry of renewable energies and it is regrettably expectedthat these pollutants will sometime soon appear in marine environmentthrough surface runoff, urban effluents and rivers. Bacteria living in estuarine and coastal sediments will be among the first targets of these new pollutants. The pseudomonads are frequently encountered in these ecosystems. They are involved in several biogeochemical cycles and are known for their high resistance to pollutants. Consequently, this study focussing on the effect of CdSe NPs on the marine strain P. fluorescensBA3SM1 is highly relevant for a number of reasons. First, it aims at improving knowledge about the interactions between bacteria and NPs. This is fundamental to use effectively NPs against pathogenic bacteria. Secondly, this study shows that CdSe NPs of 8 nm in diameter cause a decrease in the secretion of siderophorepyoverdine, a secondary metabolite having a key role in microbial ecology and also employed as a virulence factor in human pathogenic strains such as P. aeruginosa. Consequently, this study highlights that CdSe NPs can have an impact on secondary metabolism of bacteria with environmental and medical implications.