Intracellular and extracellular indole concentration in LB for BW25113, BW25113 , BW25113 , BW25113 , and BW25113

<p><b>Copyright information:</b></p><p>Taken from "Indole is an inter-species biofilm signal mediated by SdiA"</p><p>http://www.biomedcentral.com/1471-2180/7/42</p><p>BMC Microbiology 2007;7():42-42.</p><p>Published online 18 May 2007</p><p>PMCID:PMC1899176.</p><p></p> Each experiment was performed in duplicate, and one standard deviation is shown

Effect of the , , , , and mutations on biofilm formation in LB glu media

<p><b>Copyright information:</b></p><p>Taken from "Indole is an inter-species biofilm signal mediated by SdiA"</p><p>http://www.biomedcentral.com/1471-2180/7/42</p><p>BMC Microbiology 2007;7():42-42.</p><p>Published online 18 May 2007</p><p>PMCID:PMC1899176.</p><p></p> Biomass measured at 540 nm after 24 h. Each experiment was repeated two or four times, and one standard deviation is shown

Biofilm formation in LB glu at 24 h in flow cells (A) with wild-type K-12 BW25113, (B) with wild-type K-12 BW25113 with 500 μM indole, and (C) with K-12 BW25113

<p><b>Copyright information:</b></p><p>Taken from "Indole is an inter-species biofilm signal mediated by SdiA"</p><p>http://www.biomedcentral.com/1471-2180/7/42</p><p>BMC Microbiology 2007;7():42-42.</p><p>Published online 18 May 2007</p><p>PMCID:PMC1899176.</p><p></p> Scale bar is 5 μm

Acid resistance of BW25113 wild-type (W/T) and various knockout mutants in LB medium (pH 2

<p><b>Copyright information:</b></p><p>Taken from "Indole is an inter-species biofilm signal mediated by SdiA"</p><p>http://www.biomedcentral.com/1471-2180/7/42</p><p>BMC Microbiology 2007;7():42-42.</p><p>Published online 18 May 2007</p><p>PMCID:PMC1899176.</p><p></p>5) at 37°C. Each experiment was repeated two or four times and one standard deviation is shown

Effect of indole (500 μM) on the motility of BW25113 wild-type (W/T), BW25113 , BW25113 , BW25113 , and BW25113

<p><b>Copyright information:</b></p><p>Taken from "Indole is an inter-species biofilm signal mediated by SdiA"</p><p>http://www.biomedcentral.com/1471-2180/7/42</p><p>BMC Microbiology 2007;7():42-42.</p><p>Published online 18 May 2007</p><p>PMCID:PMC1899176.</p><p></p> Motility halos were measured at 8 h. Each experiment was repeated two or four times, and one standard deviation is shown. DMF (0.1 %, v/v) was used as a negative control

Seeding and culture of bovine aortic endothelial cells (BAECs) throughout PLA microchannel networks.

<p>(a) Confocal microscopy shows that the interior walls of a 200 µm diameter straight circularized microchannel can be uniformly seeded with endothelial cells that subsequently are confluently cultured in a monolayer lining the channel wall. (b) Fluorescent images show BAECs survive and maintain their morphology after 5 days in the straight circularized microchannel (bar, 50 µm). (c) BAECs seeded in four generations of branched microchannel network with diameters extending below 50 µm uniformly cover all channel walls and maintain viability after 3 days of culture (bar, 50 µm).</p

Microchannels throughout a branched network are uniformly expanded and circularized.

<p>(a) A pseudo-3D network constructed from a 7 layer stack of planar PLA branched networks before and after expansion (bars, 300 µm). (b) Due to the limitations of 2D lithographic microfabrication, the initially rectangular large channels in early branch generations have smaller aspect ratios than those in later generation branches (<i>n</i> = 1: <i>w₀</i> = 498 µm, <i>h₀</i> = 33 µm; <i>n</i> = 2: <i>w₀</i> = 81 µm, <i>h₀</i> = 31 µm; <i>n</i> = 3: <i>w₀</i> = <i>h₀</i> = 31 µm; <i>n</i> = 4: <i>w₀</i> = 14 µm, <i>h₀</i> = 35 µm). The degree of circularity (i.e., aspect ratio <i>h₀</i>/<i>w₀</i> approaching unity) is simultaneously improved across all branch generations after a single expansion step (15 psi of pressurized air for 20 min at 80°C; white bar, 500 µm; black bars, 100 µm). All experiment data are mean ± sd of 3 independent experiments. (c) A 3D branched microchannel network embedded in a 1.5×5×8 cm molded PLA block by electrostatic discharge contains a distribution of microchannel diameters that are not optimal for cell seeding (upper image). After air expansion (lower image), average diameters are significantly increased throughout and the sidewall topology becomes smoother (bar, 500 µm).</p

Enlargement and circularization of PLA microchannels by pressure-assisted expansion.

<p>(a) Microchannels with initially rectangular cross-sectional profiles are molded in PLA using a PDMS master. (b–d) Pressurized air is injected upon heating the PLA into the rubbery state (i.e., above the glass transition temperature and below the melting temperature) causing the interior air pressure force to exceed the wall resistance. The initially rectangular channels eventually attain circular cross-sections. (e–g) Corresponding images of cross-sectional profiles obtained at different times during the expansion process (<i>w₀</i> = 81 µm, <i>h₀</i> = 31 µm) (e) before expansion; (f) 80°C, 15 psi for 15 min; and (g) 80°C, 15 psi for 25 min (expansion ratio = 5; bars, 50 µm). (h) Comparison between experimental results (symbols) and model predictions (lines) capture the expansion of initially rectangular microchannels as a function of time under different processing conditions (<i>w₀</i> = <i>h₀</i> = 31 µm). Microchannel size is expressed in terms of the instantaneous width (<i>w</i>). (i) Circular cross-sectional profiles are obtained regardless of initial rectangular channel aspect ratio (<i>h₀</i>/<i>w₀</i>; 80°C at 15 psi). (j) Cross-sectional images of channels before and after expansion under the same conditions as (i) with initial aspect ratios of 2.23 (<i>w₀</i> = 16 µm, <i>h₀</i> = 35 µm), 1.00 (<i>w₀</i> = <i>h₀</i> = 31 µm), 0.38 (<i>w₀</i> = 81 µm, <i>h₀</i> = 31 µm), and 0.07 (<i>w₀</i> = 498 µm, <i>h₀</i> = 33 µm) (white bar, 100 µm; black bar, 1000 µm). All experiment data are mean ± sd of 3 independent experiments.</p

Effect of indole on colonization resistance in HeLa epithelial cells.

<p>HeLa cells were seeded in a 24 well plate and conditioned with 1 mM indole for 24 h prior to infection. A MOI of 10:1 was used for infection. Data shown are intracellular bacteria recovered from infected HeLa monolayers with indole treatment or control (solvent treatment). * denotes statistical significance relative to the solvent control at <i>p</i> < 0.05 using the Student’s <i>t</i>-test. Column bars depict mean (n = 3) and error bars represent SD.</p

The microbiota metabolite indole inhibits <i>Salmonella</i> virulence: Involvement of the PhoPQ two-component system

<div><p>The microbial community present in the gastrointestinal tract is an important component of the host defense against pathogen infections. We previously demonstrated that indole, a microbial metabolite of tryptophan, reduces enterohemorrhagic <i>Escherichia coli</i> O157:H7 attachment to intestinal epithelial cells and biofilm formation, suggesting that indole may be an effector/attenuator of colonization for a number of enteric pathogens. Here, we report that indole attenuates <i>Salmonella</i> Typhimurium (<i>Salmonella</i>) virulence and invasion as well as increases resistance to colonization in host cells. Indole-exposed <i>Salmonella</i> colonized mice less effectively compared to solvent-treated controls, as evident by competitive index values less than 1 in multiple organs. Indole-exposed <i>Salmonella</i> demonstrated 160-fold less invasion of HeLa epithelial cells and 2-fold less invasion of J774A.1 macrophages compared to solvent-treated controls. However, indole did not affect <i>Salmonella</i> intracellular survival in J774A.1 macrophages suggesting that indole primarily affects <i>Salmonella</i> invasion. The decrease in invasion was corroborated by a decrease in expression of multiple <i>Salmonella</i> Pathogenicity Island-1 (SPI-1) genes. We also identified that the effect of indole was mediated by both PhoPQ-dependent and independent mechanisms. Indole also synergistically enhanced the inhibitory effect of a short chain fatty acid cocktail on SPI-1 gene expression. Lastly, indole-treated HeLa cells were 70% more resistant to <i>Salmonella</i> invasion suggesting that indole also increases resistance of epithelial cells to colonization. Our results demonstrate that indole is an important microbiota metabolite that has direct anti-infective effects on <i>Salmonella</i> and host cells, revealing novel mechanisms of pathogen colonization resistance.</p></div