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Supplemental material

Tables

Supplemental Table 1 A.

Composition of Ag NPs from EDS analysis of NPs revealed by SEM. The biocoated Ag NPs were purified by centrifugation and then by acetone precipitation. A commercial preparation of

Ag NPs, Attostat, was analyzed as a control. ND below detection limit.

Wt % Attostat Centrifuged Acetone

preparation preparation Ag 93.4 77.4 64.2 C 6.6 8.3 11.5 O ND 3.4 4.8 N ND 2.9 7.1 S ND 0.6 1.2 P ND 0.2 ND

Table 1 B. Zeta potential measurements for the Ag NPs preparations. Assays were performed as described in Materials and methods. Data are the means and standard errors based on 10 different replicates of one sample.

Sample Zeta Potential (mV) ATTOSTAT - 46.2 ± 8.7 Centrifuged preparation - 31.1 ± 3.5 Acetone preparation - 24.1 ± 0.6 Supplemental Table 2. Primer sequences used in the construction of pseudomonad mutants lacking superoxide dismutase, SodA and SodB, and catalase isozymes, KatA and KatB.

Mutant Primer name Sequence(5' to 3') Restriction enzyme sodA SodA up-F CGG AAT TCA GCA CTT CCC GGT GGA TAT CTT EcoRⅠ

SodA up-R CGG GAT CCC AAT GCA GGC AAG GTA AAG GAC A BamHⅠ SodA down-F CGG GAT CCG CGT ATT ACC TGC GTT ACC AGA A BamHⅠ 2

SodA down-R GGA CTA GTC TTA GCT GAA AGG ATC TAC CCC G SpeⅠ

SodB up-F CGG AAT TCG TAC CTG CTG CAC ATG GTT GAG EcoRⅠ

SodB up-R CGG GAT CCT GTT CAG GTT CAC GAC ATA GGT G BamHⅠ sodB SodB down-F CGG GAT CCC ACG CTT ACT ACA TCG ACT ACC G BamHⅠ

SodB down-R GGA CTA GTT CTG GTA GCT GAA CTG TTC GTT G SpeⅠ

KatB up-F CGG AAT TCC GAG TTG CTC GGT GAA GAT GGT EcoRⅠ

KatB up-R CGG GAT CCC GCG ACG TCG AGA TGC TCA ATA BamHⅠ katB KatB down-F CGG GAT CCC GAC CTA TGG GCG TGC TAA GTG BamHⅠ

KatB down-R CCA AGC TTG GTC GGT TAT CTG ACC CTC GAC HindⅢ

KatA up-F CGG AAT TCC GGC AAG CTA CAG ACG CTG ATG EcoRⅠ

KatA up-R GCT CTA GAG CAC CTG CAA GTC AGC TTG GTT XbaⅠ

katA KatA down-F GCT CTA GAG CGC CCG GTT CTT TGT ATT TGA XbaⅠ

KatA down-R CCA AGC TTG GGA GAT CGT TAA CCC CGA TCA HindⅢ

Legends for Supplemental Figures

Supplemental Figure 1

Comparisons of absorbance spectra of the biocoated Ag NPs generated with Pythium metabolites after centrifugation and after acetone precipitation. Data are typical of three independent analyses. Ag concentrations were 31 mg/L for centrifuged preparation and 21 mg/L for the acetone preparation.

Supplemental Figure 2 3

DLS analysis of the suspensions of biocoated Ag NPs generated as centrifuged and as acetone-precipitated preparations. Data are derived from at least 10 measurements as described in Materials and methods.

Supplemental Figure 3

AFM images of suspensions of biocoated Ag NPs generated as centrifuged and as acetone precipitated preparations. Images are typical of at least 4 different fields of view from three independent studies. Height measurements are the means of 10 particles and standard error from three images.

Supplemental Figure 4

XRD spectra from the biocoated Ag NPs centrifuged preparation. Conditions for analysis were as described in Materials and methods.

Supplemental Figure 5

FTIR spectra for the centrifuged and acetone preparations of the biocoated NPs. Data are for one analysis that was typical of three independent samples.

Supplemental Figure 6

Detection of (A) catalase isozymes, KatA and KatB, and (B) Mn- and Fe- superoxide dismutase

(MnSOD and FeSOD isozymes respectively) in extracts from stationary phase wild type and mutant cells. Data are from one of three independent studies each with the same changes in isozyme patterns for the extracts from the mutants compared with the wild type. The methods followed published procedures (Kang et al. 2004).