Fig. 1

Overview of the study design. a Molecular structure of the NC probe (negative control) and KC-12 probe and attachment of KC-12 to acetyl-CoA leading to KC-12 CoA. b Flow cytometry bi-plots showing blue fluorescence produced by KC-12 probe on the y-axis vs. side scatter on the x-axis for E. coli cells possessing plasmids with/without phosphopantetheinyl transferase (PPTase) and a compatible carrier protein (PCP). The E. coli strains with either PCP or PPTase did not produce any fluorescence (1st and 2nd plot), while the strain possessing both PCP and PPTase was fluorescent when treated with KC-12 probe (3rd plot). c Nudibranch Doriopsilla fulva. d Summary of methods that were applied, indicated by gray boxes, to different body parts of nudibranchs incubated with KC-12 probe, NC probe, or not incubated with any probe. e Flow cytometry bi-plots showing blue fluorescence produced by KC-12 probe on y-axis vs. side scatter on x-axis for D. fulva skin microbiome samples (Df01 and Df02) incubated with the KC-12 probe and NC control. Incubation with KC-12 resulted in staining of 18% of the viable cells. Flow cytometry axes are on log scale