49 research outputs found

    The surface-associated exopolysaccharide of Bifidobacterium longum 35624 plays an essential role in dampening host proinflammatory responses and repressing local TH17 responses

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    The immune-modulating properties of certain bifidobacterial strains, such as Bifidobacterium longum subsp. longum 35624 (B. longum 35624), have been well described, although the strain-specific molecular characteristics associated with such immune-regulatory activity are not well defined. It has previously been demonstrated that B. longum 35624 produces a cell surface exopolysaccharide (sEPS), and in this study, we investigated the role played by this exopolysaccharide in influencing the host immune response. B. longum 35624 induced relatively low levels of cytokine secretion from human dendritic cells, whereas an isogenic exopolysaccharide-negative mutant derivative (termed sEPSneg) induced vastly more cytokines, including interleukin-17 (IL-17), and this response was reversed when exopolysaccharide production was restored in sEPSneg by genetic complementation. Administration of B. longum 35624 to mice of the T cell transfer colitis model prevented disease symptoms, whereas sEPSneg did not protect against the development of colitis, with associated enhanced recruitment of IL-17+ lymphocytes to the gut. Moreover, intranasal administration of sEPSneg also resulted in enhanced recruitment of IL-17+ lymphocytes to the murine lung. These data demonstrate that the particular exopolysaccharide produced by B. longum 35624 plays an essential role in dampening proinflammatory host responses to the strain and that loss of exopolysaccharide production results in the induction of local TH17 responses. IMPORTANCE: Particular gut commensals, such as B. longum 35624, are known to contribute positively to the development of mucosal immune cells, resulting in protection from inflammatory diseases. However, the molecular basis and mechanisms for these commensal-host interactions are poorly described. In this report, an exopolysaccharide was shown to be decisive in influencing the immune response to the bacterium. We generated an isogenic mutant unable to produce exopolysaccharide and observed that this mutation caused a dramatic change in the response of human immune cells in vitro. In addition, the use of mouse models confirmed that lack of exopolysaccharide production induces inflammatory responses to the bacterium. These results implicate the surface-associated exopolysaccharide of the B. longum 35624 cell envelope in the prevention of aberrant inflammatory responses

    Three Warm Jupiters around Solar-analog Stars Detected with TESS*

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    We report the discovery and characterization of three giant exoplanets orbiting solar-analog stars, detected by the TESS space mission and confirmed through ground-based photometry and radial velocity measurements taken at La Silla observatory with FEROS. TOI-2373 b is a warm Jupiter orbiting its host star every ∼13.3 days, and is one of the most massive known exoplanet with a precisely determined mass and radius around a star similar to the Sun, with an estimated mass of m _p = 9.30.2+0.2Mjup{9.3}_{-0.2}^{+0.2}\,{M}_{\mathrm{jup}} and a radius of r _p = 0.930.2+0.2Rjup{0.93}_{-0.2}^{+0.2}\,{R}_{\mathrm{jup}} . With a mean density of ρ=14.41.0+0.9gcm3\rho ={14.4}_{-1.0}^{+0.9}\,{\rm{g}}\,{\mathrm{cm}}^{-3} , TOI-2373 b is among the densest planets discovered so far. TOI-2416 b orbits its host star on a moderately eccentric orbit with a period of ∼8.3 days and an eccentricity of e = 0.320.02+0.02{0.32}_{-0.02}^{+0.02} . TOI-2416 b is more massive than Jupiter with m _p = 3.00.09+0.10Mjup{3.0}_{-0.09}^{+0.10}\,{M}_{\mathrm{jup}} , however is significantly smaller with a radius of r _p = 0.880.02+0.02,Rjup{0.88}_{-0.02}^{+0.02},{R}_{\mathrm{jup}} , leading to a high mean density of ρ=5.40.3+0.3gcm3\rho ={5.4}_{-0.3}^{+0.3}\,{\rm{g}}\,{\mathrm{cm}}^{-3} . TOI-2524 b is a warm Jupiter near the hot Jupiter transition region, orbiting its star every ∼7.2 days on a circular orbit. It is less massive than Jupiter with a mass of m _p = 0.640.04+0.04Mjup{0.64}_{-0.04}^{+0.04}\,{M}_{\mathrm{jup}} , and is consistent with an inflated radius of r _p = 1.000.03+0.02Rjup{1.00}_{-0.03}^{+0.02}\,{R}_{\mathrm{jup}} , leading to a low mean density of ρ=0.790.08+0.08gcm3\rho ={0.79}_{-0.08}^{+0.08}\,{\rm{g}}\,{\mathrm{cm}}^{-3} . The newly discovered exoplanets TOI-2373 b, TOI-2416 b, and TOI-2524 b have estimated equilibrium temperatures of 86010+10{860}_{-10}^{+10} K, 108010+10{1080}_{-10}^{+10} K, and 110020+20{1100}_{-20}^{+20} K, respectively, placing them in the sparsely populated transition zone between hot and warm Jupiters

    Cartoon Dioramas in Motion

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    Cartoon animations delight the audience with moving charactersshading, apparent motion and virtual lighting on a toy-car model

    Cartoon dioramas in motion

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