Effect of <i>csrA</i> on message stability of <i>fimA</i> (A) and <i>lrhA</i> (B) in K-12 strain MG1655.

<p>Total RNA was harvested from late log growth phase. The mRNA stability of <i>fimA</i>, <i>lrhA</i> or <i>icd</i> (housekeeping control) was assessed for 10 mins after addition of rifampicin. The relative intensities of the wild-type and the mutant was compared to the intensity of <i>icd</i> mRNA. Normalized transcript levels at time zero prior to rifampicin treatment was set at 100%. This experiment was repeated two times.</p

Orientation of <i>fim</i> switch in CFT073 (A) and MG1655 (B).

<p>Direction of the <i>fim</i> switch was determined by using a PCR inversion assay. Densitometric analysis was performed to assess relative intensity of bands from agarose gels by using a software, ImageJ. The OFF or ON band intensity of the wild-type was set at 100%. Two independent replicates for each strain were used for this assay. This assay was repeated three times.</p

Biofilm formation on various abiotic surfaces in UPEC CFT073.

<p>Crystal violet staining was performed to assess air-liquid biofilm formation on abiotic surfaces such as polystyrene (A) or PVC (B) at 48 hours, whereas crystal violet staining was performed to assess biofilm biomass on glass (C) at 6, 12, 24 and 48 hours. Strains were grown in LB broth with appropriate antibiotics without aeration at room temperature. Bars represent means of three experiments with three replicates per sample. The error bars represent standard errors of three replicates.</p

Effect of <i>uvrY</i> and <i>csrA</i> on <i>fimB</i>, <i>fimE</i> and <i>fimA</i> transcription in UPEC strain CFT073.

<p><b>A</b>. Transcript levels of <i>fimB</i>, <i>fimE</i> and <i>fimA</i> were evaluated by quantitative RT-PCR. The <i>rrnA</i> was used as an internal control. <b>B</b>. Relative expression levels of various transcripts were calculated by normalization of the actual intensity of bands with <i>rrnA</i> control and expressed as fold change relative to the wild-type. The wild-type was set at one. Bars represent mean ± S.E.M of three replicates.</p

Expression of <i>fim</i> operon in K-12 strain MG1655.

<p>β-galalactosidase assay was performed in relevant genetic background harboring a single copy plasmid with <i>fimA-lacZYA</i> transcriptional fusions either at invertible or at locked ON orientation. Bars represent means ± SEM of three experiments.</p

Direct <i>in-vivo</i> binding of UvrY with <i>luxS</i> promoter by chromatin immunoprecipitation assay (ChIP).

<p>The occupancy of UvrY at the <i>csrA</i>, <i>csrB</i> and <i>luxS</i> promoters in <i>E</i>. <i>coli</i> was analyzed by ChIP using an anti-UvrY antibody. Purified DNA was PCR amplified using target specific primers. Genomic DNA and cell lysates were used as template for additional controls in PCR reaction. A 100 bp ladder marker was used for size comparison of amplicons. Expected sizes for all amplicons were between 300–400 bp.</p

Non-Noble-Metal-Based Porphyrin Covalent Organic Polymers as Additive-/Annealing-Free Electrocatalysts for Water Splitting and Biomass Oxidation

Though metalloporphyrins have proved their efficiency as a class of efficient electrocatalysts, their practical use is often restricted due to poor stability and lack of an effective electrochemical surface. Combining metalloporphyrins in the skeleton of covalent organic polymers, though, is an effective strategy for developing efficient electrocatalysts for OER and HER; due to the restricted conductivity of such materials, addition of external additives or annealing is a must, which increases the cost of the material development. Here, we report two metalloporphyrin-based covalent organic polymers, COP-POR-Ni and COP-POR-Co, which work as excellent annealing- and additive-free electrocatalysts for overall water splitting in an alkaline medium. The polymers achieved a current density of 1 mA/cm2 at 300 and 370 mV with turnover frequencies (TOFs) of 9.1 × 10–3 and 2.68 × 10–3 s–1 at 2 mA/cm2 for COP-POR-Ni and COP-POR-Co, respectively, for alkaline water oxidation. The catalysts are also active for the selective conversion of 5-hydroxymethylfurfural (HMF), a plant biomass carbohydrate, oxidation to a platform chemical 2,5-furandicarboxylic acid (FDCA) with the coproduction of hydrogen at the cathode. HER activity was also achieved with overpotentials of 468 and 348 mV at a current density of 1 mA cm–2 for COP-POR-Ni and COP-POR-Co in an acidic medium, respectively

List of oligonucleotides used in the study.

<p>List of oligonucleotides used in the study.</p

Effect of <i>uvrY</i> on AI-2 accumulation and expression of <i>luxS</i>::<i>lacZ</i> fusion.

<p>(A) AI-2 accumulation in the supernatant was assayed by <i>Vibrio harveyi</i> reporter assay in SM1005 (<i>luxS</i>::<i>lacZ</i>), SM1007 (Δ<i>uvrY luxS</i>::<i>lacZ</i>) and SM1010 (Δ<i>uvrY/</i>p<i>uvrY luxS</i>::<i>lacZ</i>) for a period of 24 hours. (B) Expression of the fusion in the strains was monitored by β-galactosidase assay for 24 hours. Dotted lines indicate growth of corresponding bacterial strains. The graphs represent mean of three experiments. Asterisk marks are provided for a representative data point used for calculation of significance.</p

Bacterial strains and plasmids used in this study.

<p>Bacterial strains and plasmids used in this study.</p