Fig. 1

(A) Growth-inhibitory and quorum-modulatory effect of Silversol on P. aeruginosa. Bacterial growth was measured as OD₇₆₄; OD of pyoverdine and pyocyanin was measured at 405 nm and at 520 nm respectively. Pyoverdine Unit and Pyocyanin Unit were calculated as the ratio OD₄₀₅/OD₇₆₄ and OD₅₂₀/OD₇₆₄(an indication of pigment production per unit of growth); Ofloxacin (0.3 µg/mL) inhibited growth by 76**%±0.1 with affecting pigment production. **p < 0.01, ***p < 0.001; minus sign (-) in parentheses indicate a decrease over control; (B) P. aeruginosa grows at slower growth rate in presence of sub-MIC of Silversol. Generation time of P. aeruginosa in presence and absence of Silversol was calculated to be 12.15 h and 11.17 h. For each time point shown in this growth curve, pigment quantification was also done. To avoid overcrowding of the graph, data pertaining to pigments is presented separately in Figure S5; (C) Silversol pre-treated P. aeruginosa exhibits enhanced haemolysis on blood agar plates. Silver-pretreated P. aeruginosa when inoculated onto blood agar plates, produced a clearer zone of haemolysis than its control counterpart receiving no previous exposure to silver; (D) Silversol pre-treatment enhances P. aeruginosa’s susceptibility to augmentin and streptomycin. Silver-pretreated cells seem to be altered in their response to antibiotics with respect to growth as well as QS-regulated pigmentation. On these plates of cation-adjusted Muller-Hinton agar, clear zones of inhibition can be seen surrounding the discs of augmentin and streptomycin in the experimental plate inoculated with silver-pre-treated cells, while such zones are absent (augmentin) or faint (streptomycin) from the control plate inoculated with P. aeruginosa having no previous silver-exposure