Fig. 1
From: Non-antibiotic pharmaceuticals promote conjugative plasmid transfer at a community-wide level
Experimental design and methods used in this study. Fluorescently mCherry-tagged environmental bacterium Pseudomonas putida hosting the broad-host-range self-transmissible IncP-α plasmid RP4 was added to the activated sludge community in liquid phase mating assays. The RP4 plasmid hosts multiple resistance genes against ampicillin, kanamycin, and tetracycline, and was here used in a gfp-tagged form. The expression of GFP was chromosomally repressed in the donor strain, and only expressed upon success transfer in the recipient strain. The broth mating was exposed to different non-antibiotic pharmaceuticals. a The transfer was visualized by a fluorescence microscopy, followed by quantification and calculation of transfer ratio. b Fluorescence-activated cell sorting (FACS) of putative recipients and transconjugants and subsequent 16S rRNA gene amplicon sequencing were employed to investigate shifts in recipient and transconjugant communities upon exposure to these non-antibiotic pharmaceuticals. c Microbial permissiveness (uptake ability) towards the plasmid were also identified