Impact of temperature and SOS response on gene expression.

<p>β-galactosidase assays are performed with strains ω7450 (<i>intIA-lacZ</i>), ω7286 (<i>intIA-lacZ lexAind-</i>), ω7453 (<i>recN-lacZ</i>) and N16961 (<i>lacZ</i>) after mitomycin C addition (+) or not, harvested at the end of exponential growth.</p

Sub-MIC tobramycin treatment induces ROS formation in <i>V.</i>cholerae and not in <i>E. coli</i>.

<p>Histogram bars show the ratio of rhodamine fluorescence in the presence of the specified antibiotic over fluorescence in LB and thus reflect the induction of ROS formation. Tobramycin (TOB) and ciprofloxacin (CIP) concentrations were respectively 0.01 µg/ml and 0.005 µg/ml for <i>V. cholerae</i>, and 0.1 µg/ml and 0.05 µg/ml for <i>E. coli</i>. Exp phase stands for exponential phase i.e. an OD600 nm of 0.5. End exp phase stands for end of exponential phase i.e. an OD600 nm of 0.8.</p

Bacterial strains and plasmids.

<p>Bacterial strains and plasmids.</p

<i>intIA</i> and cassette array expression during growth and according to growth conditions.

<p>β-galactosidase assays are performed with strains ω8320 (promoter cassette array:<i>lacZ</i>) (A and C) and ω7450 (integrase:<i>lacZ</i>) (B and D). In A and B, growth was performed at 29°C in M63 glucose casamino serine vitamin B1 (black), in Marine broth (grey) and in classical LB (striped). “expo” means exponential growth. In C and D, growth was performed in LB without NaCl, (-NaCl), with classical concentration (LB) or with high NaCl concentration (+ NaCl) and samples are harvested at the end of exponential growth.</p

RpoS protects <i>E.</i>coli and <i>V. cholerae</i> from tobramycin-dependent SOS induction and ROS formation.

<p>A and B. Histogram bars show the ratio of GFP fluorescence in the presence of antibiotic over fluorescence of the wild type strain grown in LB and thus reflect the induction of SOS. pRssB+ is pTOPO-RssB+ (pA209). pIraD+ is pTOPO-IraD+ (pA208). pRpoS+ is pTOPO-RpoS+ (pA237). Tobramycin (TOB) concentrations were 0.01 µg/ml for <i>V. cholerae</i> and 0.1 µg/ml for <i>E. coli</i>. Spermidine (Sper) was used at a final concentration of 10 mM. 2,2 Dipyridil (DP) was used at a final concentration of 0.5 mM. A: <i>E. coli</i> p9092. B: <i>V. cholerae</i>::p4640. C and D. Histogram bars show the ratio of rhodamine fluorescence in the presence of Tobramycin (TOB). C. Cultures were treated with TOB 0.01 µg/ml and rhodamine fluorescence was measured at OD600 nm 0.2. D. Cultures were treated with TOB 0.001 µg/ml and rhodamine fluorescence was measured at OD600 nm 0.5.</p

Oxidized guanine incorporation after tobramycin treatment induces SOS in the <i>E.</i>coli base excision repair deficient mutant.

<p>Histogram bars show the ratio of GFP fluorescence in the presence of antibiotic over fluorescence of the wild type strain grown in LB and thus reflect the induction of SOS. TOB: tobramycin 0.1 µg/ml. KAN: kanamycin 0.2 µg/ml. WT is <i>E. coli</i> is BER proficient.</p

Oligonucleotides.

<p>Oligonucleotides.</p

Sub-MIC aminoglycosides induce SOS in other pathogens.

<p>Histogram bars show the ratio of GFP fluorescence in the presence of antibiotic over fluorescence in LB and thus reflect the induction of SOS by the antibiotic. Tobramycin (TOB) concentrations were 0.01 µg/ml for <i>Klebsiella pneumoniae</i> and 0.0025 µg/ml for <i>Photorhabdus luminescens</i>. Mitomycin C (MMC) was used at 0.1 µg/ml.</p

Regulatory region of <i>intIA</i> and cassette array and identification of cassette array transcriptional start.

<p>The transcriptional start sites (+1) are indicated by arrow and capital and bold letters. The -10 and -35 promoters boxes are shown in grey with bold characters. The coding sequences are indicated with capital letters. Positions of <i>lacZ</i> transcriptional fusions are notified by a line. The CRP and LexA boxes mutations are indicated with an arrow and grey boxes (CRP box* and LexA box*). The <i>attI</i> recombination point is indicated by a vertical bar.</p

Factors modulating SOS induction by tobramycin in <i>V.</i>cholerae.

<p>Histogram bars show the ratio of GFP fluorescence in a given strain in the presence of antibiotic over fluorescence of the same strain grown in LB and thus reflect the induction of SOS by the antibiotic. p0 stands for empty pTOPO plasmid. pMutY+ stands for pTOPO-MutY+ (p9476). TOB: tobramycin 0.01 µg/ml. MMC: mitomycin C 0.1 µg/ml. DP: 2,2 Dipyridyl 0.5 mM.</p