Legionella lipoprotein activates toll-like receptor 2 and induces cytokine production and expression of costimulatory molecules in peritoneal macrophages

Legionella bacterium, an intracellular pathogen of mononuclear phagocytes, causes acute fatal pneumonia, especially in patients with impaired cellular immune responses. Until recently, however, the toll-like receptor (TLR) engagement of bacterial proteins derived from Legionella is uncertain. We previously showed that a 19-kDa highly conserved peptidoglycan-associated lipoprotein (PAL) of Legionella pneumophila induced the PAL-specific B cell and T cell responses in mice. In this study, we observed that the rPAL antigen of L. pneumophila, as an effector molecule, activated murine macrophages via TLR2 and produced proinflammatory cytokines such as IL-6 and TNF-α. In both BALB/c and TLR4-deficient C3H/HeJ mice, pretreatment of macrophages with anti-TLR2 mAb showed severely impaired cytokine production in response to the rPAL. In addition, in vitro the rPAL treatment increased the cell surface expression of CD40, CD80, CD86 and MHC I/II molecules. We further showed that the synthetic CpG-oligodeoxynucleotides (CpG ODN) coadministered with the rPAL enhanced IL-12 and IL-6 production and expression of CD40, CD80 and MHC II compared to the rPAL treatment alone. In conclusions, these results indicate that Legionella PAL might activate macrophages via a TLR2-dependent mechanism which thus induce cytokine production and expression of costimulatory and MHC molecules.     

Syringaresinol causes vasorelaxation by elevating nitric oxide production through the phosphorylation and dimerization of endothelial nitric oxide synthase

Nitric oxide (NO) produced by endothelial NO synthase (eNOS) plays an important role in vascular functions, including vasorelaxation. We here investigated the pharmacological effect of the natural product syringaresinol on vascular relaxation and eNOS-mediated NO production as well as its underlying biochemical mechanism in endothelial cells. Treatment of aortic rings from wild type, but not eNOS(-/-) mice, with syringaresinol induced endothelium-dependent relaxation, which was abolished by addition of the NOS inhibitor N(G)-monomethyl-L-arginine. Treatment of human endothelial cells and mouse aortic rings with syringaresinol increased NO production, which was correlated with eNOS phosphorylation via the activation of Akt and AMP kinase (AMPK) as well as elevation of intracellular Ca(2+) levels. A phospholipase C (PLC) inhibitor blocked the increases in intracellular Ca(2+) levels, AMPK-dependent eNOS phosphorylation, and NO production, but not Akt activation, in syringaresinol- treated endothelial cells. Syringaresinol-induced AMPK activation was inhibited by co-treatment with PLC inhibitor, Ca(2+) chelator, calmodulin antagonist, and CaMKKβ siRNA. This compound also increased eNOS dimerization, which was inhibited by a PLC inhibitor and a Ca(2+)-chelator. The chemicals that inhibit eNOS phosphorylation and dimerization attenuated vasorelaxation and cGMP production. These results suggest that syringaresinol induces vasorelaxation by enhancing NO production in endothelial cells via two distinct mechanisms, phosphatidylinositol 3-kinase/Akt- and PLC/Ca(2+)/CaMKKβ-dependent eNOS phosphorylation and Ca(2+)-dependent eNOS dimerization.     

Controlled trapping and rotation of carbon nanotube bundle with optical tweezers

Controlled optical trapping and rotation of carbon nanotube bundle (CNTB) including single-walled and multi-walled carbon nanotube in aqueous solution, were performed using the optical tweezers. Vertical and horizontal trapping of CNTB was performed depending on the size of CNTB and the trapping depth. In addition, four different rotations of the trapped CNTB were described and explained by the interaction between CNTB and the laser field, and the convection of the aqueous solution induced by thermalphoresis effect. These results will pave the way to assemble some CNTs-based devices such as micro motors.     

Working group report: Heavy-ion physics and quark-gluon plasma

This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported.     

The effect of hydrogenation in HgxCd1 − xTe thin films grown on p-CdTe (211) B substrates

Fourier transform infrared (FTIR) transmission, Hall effect, and nuclear resonance reaction measurements have been carried out to investigate the effect of hydrogenation on the deep levels and the hydrogen depth profiling in nominally undoped Hg_xCd_{1 − x}Te layers grown on undoped p-CdTe (211) B-orientation substrates by molecular beam epitaxy. After hydrogenation, the FTIR spectra showed that the transmittance intensity increased in comparison to that of the as-grown Hg_xCd_{1 − x}Te and that the absorption edge shifted to the short wavelength range. Hall effect measurements showed that the carrier concentration decreased and the mobility increased after hydrogenation. After hydrogenation, p-type Hg_xCd_{1 − x}Te is converted to n-type Hg_xCd_{1 − x}Te with high resistivity. Nuclear resonance raaction measurements show that the concentration and the penetration depth of the hydrogen atom in n-Hg_0.77Cd_0.23Te are 3.5% and 640 Å, respectively. The areal density of the hydrogen-containing layer at the surface of the hydrogenated n-Hg_0.77Cd_0.23Te film is 4.39 × 10¹⁵ atoms/cm². These results indicate that hydrogen atoms not only effectively passivate impurities or defects in the Hg_xCd_{1 − x}Te film but also change the carrier type of p-Hg_xCd_{1 − x}Te.     

X‐ray Crystallography and Vibrational Spectroscopy Reveal the Key Determinants of Biocatalytic Dihydrogen Cycling by [NiFe] Hydrogenases

[NiFe] hydrogenases are complex model enzymes for the reversible cleavage of dihydrogen (H₂). However, structural determinants of efficient H₂ binding to their [NiFe] active site are not properly understood. Here, we present crystallographic and vibrational‐spectroscopic insights into the unexplored structure of the H₂‐binding [NiFe] intermediate. Using an F₄₂₀‐reducing [NiFe]‐hydrogenase from Methanosarcina barkeri as a model enzyme, we show that the protein backbone provides a strained chelating scaffold that tunes the [NiFe] active site for efficient H₂ binding and conversion. The protein matrix also directs H₂ diffusion to the [NiFe] site via two gas channels and allows the distribution of electrons between functional protomers through a subunit‐bridging FeS cluster. Our findings emphasize the relevance of an atypical Ni coordination, thereby providing a blueprint for the design of bio‐inspired H₂‐conversion catalysts.     

Relevant, systematic variation of morphology and magnetism according to annealing in InMnP:Zn

InMnP:Zn epilayers doped with Mn (0.290 at.%) were annealed at 723-873 K for 60 s and 473-573 K for 30 min. Using Auger electron spectroscopy, the changes in concentration profiles of the epilayers correlated to the ferromagnetic origin as a function of the annealing conditions. The epilayers annealed at 723-873 K for 60 s exhibited InMn₃ persisting up to 583 K. For InMnP:Zn epilayers annealed at 523-573 K for 30 min, the concentration depth profiles remained flat so that the stoichiometry was well maintained without precipitates such as InMn₃ and MnP comparable to the as-grown InP:Zn before doping Mn. These samples showed clear ferromagnetic hysteresis loops. Curie temperature was about 150 K. A ferromagnetic hysteresis loop was obtained even at very lower annealing temperature of 473 K.     

Short-term changes in delta(13)C and delta(15)N signatures of water discharged from grazed grasslands

The composition of dissolved organic matter (DOM) in a soil is the product of a variety of soil processes. Changes in the composition of DOM in water discharged from soil should, therefore, give an important insight into modifications in these soil processes. We hypothesise that these processes in soils, under different grassland management regimes, would be affected to different extents by the short-term disturbance of a storm event and that evidence of this could be detected in delta(13)C and delta(15)N signatures in drainage and surface runoff waters. During a storm event we collected discharge waters from 1 ha grassland lysimeters, with or without artificial drainage, which received contrasting fertiliser inputs, and delta(13)C and delta(15)N signatures were determined. Changes in (13)C enrichment during the storm event were clearly identifiable, as were differences between plots for (13)C and (15)N, illustrating that this technique has potential to be a useful tool for identifying and investigating short- and long-term changes in soil organic matter dynamics. Copyright 1999 John Wiley & Sons, Ltd.     

Non-stackable molecules assemble into porous crystals displaying concerted cavity-changing motions

With small molecules, it is not easy to create large void spaces. Flat aromatics stack tightly, while flexible chains fold to fill the cavities. As an intuitive design to make open channels inside molecularly constructed solids, we employed propeller-shaped bicyclic triazoles to prepare a series of aromatic-rich three-dimensional (3D) building blocks. This modular approach has no previous example, but is readily applicable to build linear, bent, and branched arrays of non-stackable architectural motifs from existing flat aromatics by single-pot reactions. A letter H-shaped molecule thus prepared self-assembles into porous crystals, the highly unusual stepwise gas sorption behaviour of which prompted in-depth studies. A combination of single-crystal and powder X-ray diffraction analysis revealed multiple polymorphs, and sterically allowed pathways for their reversible interconversions that open and close the pores in response to external stimuli.

Like non-collapsible open voids within stacks of steel H-beams, a non-covalent assembly of three-dimensional aromatics produces porous crystals. Concerted motions of the molecular H-beams open and close the cavities in response to external stimuli.     

Development of new cleanup method of polychlorinated dibenzo-p-dioxins/dibenzofurans in fish by freezing-lipid filtration

Freezing-lipid filtration as a new method has been developed for the rapid determination of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/Fs) in biological samples. This method can effectively reduce the time of sample pretreatment, labor and amount of solvents compared with conventional methods. By freezing-lipid filtration procedure, about 90% of lipids in extract could be removed without any significant loss of PCDD/Fs. For further cleanup of extracts after freezing-lipid filtration, automatic parallel LC columns including silica gel, alumina and carbon columns were applied. During automatic parallel LC columns cleanup, most of co-extracted interferences such as residue lipids and fatty acids could be eliminated and dioxins could be separated from many other dioxin-like congeners such as polychlorinated biphenyls by this procedure. The extracts after cleanup were analyzed by high-resolution gas chromatography (HRGC)/high-resolution mass spectrometry (HRMS) using an isotope dilution method. The average recoveries and relative standard deviation (R.S.D.) of 17 native congeners in the spiked fish samples at 8-80 pg/g (n = 3) were ranged between 85.3 and 117.2% and 5.7-20.3%, respectively.