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The RNA processing enzyme polynucleotide phosphorylase negatively controls biofilm formation by repressing poly-N-acetylglucosamine (PNAG) production in Escherichia coli C

Thomas Carzaniga, Davide Antoniani, Gianni Dehò, Federica Briani* and Paolo Landini*

Author Affiliations

Department of Biosciences, University of Milan, Via Celoria 26, Milan, 20133, Italy

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BMC Microbiology 2012, 12:270  doi:10.1186/1471-2180-12-270

Published: 21 November 2012

Additional files

Additional file 1: Table S1:

Primers used in this work.

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Additional file 2: Figure S1:

Effects of inactivation of genes encoding adhesion factors and biofilm determinants in the C-1a strain. C-1a (pnp+) and its derivatives carrying mutations in genes encoding for adhesion determinants (ΔpgaC, impaired in PNAG production; ΔbcsA, impaired in cellulose production; ΔcsgA, impaired in curli production; ΔwcaD, impaired in colanic acid production) were grown over night in M9Glu/sup at 37°C in glass flasks. Cell aggregates were stained with crystal violet.

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Additional file 3: Figure S2:

Surface adhesion of pnp deletion mutant derivative of E. coli MG1655 and identification of the adhesion factor involved. Surface adhesion to polystyrene microtiter plates by MG1655 (pnp+), KG206 (Δpnp), and KG206 derivatives carrying mutations in genes coding for adhesion determinants (ΔpgaA, AM56; ΔbcsA, AM72; ΔcsgA, AM70; ΔwcaD, AM105) was assessed at 37°C in M9Glu/sup. Adhesion unit values, assessed as previously described [33], are the average of three independent experiments and standard deviation is shown. The overall p-value obtained by ANOVA is indicated in the graph. Letters provide the representation for posthoc comparisons. According to posthoc analysis (Tukey’s HSD, p < 0.05), means sharing the same letter are not significantly different from each other.

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Additional file 4: Figure S3:

pgaA mRNA decay analysis. Bacterial cultures of C-1a (pnp+), C-5691 (Δpnp) and C-5938 (ΔcsrA) were grown up to OD600 = 0.8 in M9Glu/sup, rifampicin (final concentration of 0.4 mg/ml) was added, and samples for RNA extraction were taken at different time points immediately before (t = 0) and after antibiotic addition. pgaA mRNA degradation kinetics was estimated by quantitative RT-PCR with oligonucleotides PL99 and PL100, as detailed in Methods.

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