Enhancement of the Hydrogen-Storage Properties of MgH2 by the Addition of Ni, NaAlH4, Ti, and CNT via Reactive Mechanical Grinding.

MgH2 was used as the starting material in this study. A sample with the composition of 84 wt% MgH2 + 10 wt% Ni + 2 wt% NaAlH4 + 2 wt% Ti + 2 wt% CNT (named MgH2-10Ni-2NaAIH4-2Ti-2CNT) was prepared by the reactive mechanical grinding. Hydriding and dehydriding property measurements, X-ray diffraction (XRD) analyses, and microstructural observations were then performed. The activation of the sample was not required. At the first cycle (n = 1), the sample absorbed 2.84 wt% H for 5 min, 3.75 wt% H for 10 min, 4.09 wt% H for 15 min, and 4.17 wt% H for 60 min at 593 K under 12 bar H2. The MgH2-10Ni-2NaAlH4-2Ti-2CNT sample showed quite a high hydriding rate at a relatively low temperature of 423 K under 12 bar H2 (at n = 4), absorbing 2.81 wt% H for 5 min, 3.23 wt% H for 10 min, and 3.56 wt% H for 60 min. The reactive mechanical grinding of MgH2 with Ni, NaAlH4, Ti, and CNT is considered to create defects on the surface and in the interior of MgH2 as well as decrease the particle size of MgH2-

Anti-inflammatory effect of gamma-irradiated genistein through inhibition of NF-κB and MAPK signaling pathway in lipopolysaccharide-induced macrophages.

Genistein was irradiated with γ-irradiation at doses of 0, 10, 30, 50, 100, and 150 kGy. We observed that the decrease in the genistein peak after gamma irradiation was concomitant with the appearance of several new peaks. 150 kGy gamma-irradiated genistein did not exert cytotoxicity in macrophages, and inhibited inducible nitric oxide synthase-mediated nitric oxide production and pro-inflammatory cytokines level, such as tumor necrosis factor-α, interleukin-6 and interleukin-1ß, in lipopolysaccharide (LPS)-induced macrophages. The treatment of LPS-stimulated macrophages with 150 kGy gamma-irradiated genistein resulted in a significant decrease in cyclooxygenase-2 levels, as well as the expression of cell surface molecules, such as CD80 and CD86. Furthermore, we also found that the anti-inflammatory action of 150 kGy gamma-irradiated genistein occurred through an inhibition of mitogen-activated protein kinases (extracellular signal-regulated kinase 1/2, p38 and c-Jun N-terminal kinase) and nuclear factor-κB signaling pathways based on a toll-like receptor 4 in macrophages, which may be speculated that several radiolysis products of genistein transformed by gamma-irradiation induce the inhibition of pro-inflammatory mediators. From these findings, it seems likely that gamma-irradiated genistein could play a potent role in the treatment of inflammatory disease as a value-added product in the medical industry.

Epigallocatechin-3-gallate-mediated Tollip induction through the 67-kDa laminin receptor negatively regulating TLR4 signaling in endothelial cells.

BACKGROUND: Green tea polyphenol epigallocatechin-3-gallate (EGCG) has the potential to impact a variety of inflammation-related diseases; however, the anti-inflammatory action of EGCG in endothelial cells has not been understood. Recently, we demonstrated that the 67-kDa laminin receptor (67LR) acts as a cell-surface EGCG receptor. AIM: This research was carried out to clarify the molecular basis for the down-regulation of toll-like receptor 4 (TLR4) signal transduction by EGCG in lipopolysaccharide (LPS)-stimulated endothelial cells. RESULTS: RNAi-mediated silencing of 67LR resulted in an abrogation of the inhibitory action of EGCG on the LPS-induced activation of downstream signaling pathways. Also, we found that EGCG induced a rapid upregulation of Toll-interacting protein (Tollip), a negative regulator of TLR signaling, through 67LR in endothelial cells. RNAi-mediated silencing of Tollip impaired the TLR4 signaling inhibitory activity of EGCG. Additionally, silencing of Tollip resulted in an abrogation of the inhibitory action of EGCG on the LPS-induced expressions of cell-associated adhesion molecules, such as ICAM-1 and VCAM-1. CONCLUSION: Taken together, these novel findings provide new insights into an understanding of negative regulatory mechanisms of the TLR4 signaling pathway and effective therapeutic intervention for the treatment of inflammatory disease.

Characterization and identification of distinct Mycobacterium massiliense extracellular proteins from those of Mycobacterium abscessus.

Mycobacterium massiliense is an emerging pathogen and very similar to Mycobacterium abscessus of rapidly growing mycobacteria in the phenotype and genotype. Pathogenic bacteria secrete a diversity of factors into extracellular medium which contribute to the bacterial pathogenicity. In the present study, we performed the comparative proteome analysis of culture filtrate proteins from a clinical isolate of M. massiliense and M. abscessus strains using two-dimensional gel electrophoresis and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). Interestingly, 9 proteins of M. massiliense were distinctly expressed from those of M. abscessus. Bioinformatic analysis of the identified proteins revealed that 3 unique proteins corresponded to serine/arginine rich protein, membrane protein from Streptomyces coelicolor, and one hypothetical protein from Corynebacterium efficiens YS-314, respectively. Culture filtrate proteins from M. massiliense induced the release of pro-inflammatory cytokines from macrophages in a dose-dependent manner but not that from M. abscessus. Taken together, the functional study on the identified proteins uniquely produced from M. massiliense may provide not only the clues for the different pathogensis, but also help develop the diagnostic tools for the differentiation between two mycobacterial species.

Induction of macrophage death by clinical strains of Mycobacterium kansasii.

Mycobacterium kansasii is a facultative intracellular pathogen causing pulmonary disease in immunocompetent patients. Little is known about the host defense against M. kansasii and its intracellular survival strategy inside macrophages. In the present study, we obtained six clinical isolates from patients with M. kansasii pulmonary disease and investigated the intracellular growth and cytotoxic effects of M. kansasii inside mouse bone marrow-derived macrophages (BMDM) as well as cytokine secretion from BMDM. Interestingly, two isolates, SM-1 and 2693-20, displayed faster growth rates and higher levels of TNF-alpha secretion from macrophages when compared to the other strains. In addition, SM-1 and 2693-20 also induced massive cell death in BMDM and THP-1 acute monocytic leukemia cells, while the slow growing strains induced significantly lower levels of cell death. This cytotoxicity was mainly caused by necrosis, not apoptosis and it was TNF-alpha-independent. Caspase inhibitors failed to block M. kansasii-induced macrophage death. In addition, necrosis caused by the fast growing strains was accompanied by the loss of mitochondrial membrane potential (DeltaPsi(m)). When dissipation of DeltaPsi(m) was inhibited by the classical mitochondrial permeability transition (MPT) inhibitor cyclosporine A (CsA), macrophage necrosis was reduced. These results suggest that clinical isolates of M. kansasii that grow faster in macrophages induce higher levels of necrosis in a DeltaPsi(m) loss-dependent manner.

Differentially expressed genes in Mycobacterium tuberculosis H37Rv under mild acidic and hypoxic conditions.

The survival mechanism of dormant tubercle bacilli is unknown; however, accumulating evidence indicates that Mycobacterium tuberculosis can survive and persist in hypoxic and mildly acidic microenvironments. Such conditions are found in the acidic vacuoles of macrophages, which M. tuberculosis is known to target. We used DECAL (differential expression using customized amplification library) to identify the genes expressed under acidic and hypoxic conditions, following the cultivation of M. tuberculosis H37Rv at an acidic pH and/or under hypoxic or anoxic conditions in vitro. Of 960 clones analysed, 144 genes, consisting of 71 induced and 8 repressed genes, were identified by sequencing and divided into functional categories to characterize their cellular roles. In general, the genes induced under acidic and hypoxic conditions were involved in the biosynthesis of secondary metabolites (e.g. pks4), lipid metabolism, energy production (e.g. pckA) and cell wall biogenesis (e.g. Rv0696 and plcB). The combination of genes identified may explain the energy processing and energy storage of M. tuberculosis during latent infection. These findings not only enhance our understanding of the mechanism of dormancy, but they also may be useful in the design of therapeutic tools and vaccines for latent tuberculosis.

Improved sensitivity of diagnosis of tuberculosis in patients in Korea via a cocktail enzyme-linked immunosorbent assay containing the abundantly expressed antigens of the K strain of Mycobacterium tuberculosis.

Tuberculosis (TB) is the leading cause of death from a single infectious agent in Korea. In this study, we compared the proteins present in culture filtrates from Mycobacterium tuberculosis strain K, which is the dominant clinical isolate in Korea, with those present in culture filtrates from M. tuberculosis H37Rv. Several differences in expression were detected between the two strains for those proteins with a molecular mass of <20 kDa. ESAT-6, HSP-X, and CFP-10 were found to be abundantly expressed in the strain K culture filtrates by liquid chromatography-electrospray ionization-time of flight mass spectrometry. The serodiagnostic potentials of recombinant antigens rESAT-6, rHSP-X, and rCFP-10 and two native antigens (Ag85 and PstS1) were evaluated by Western blot analysis and enzyme-linked immunosorbent assay (ELISA) using sera collected from 46 TB patients with active disease and 46 healthy controls. As for our ELISA results, HSP-X was superior to the other antigens in terms of sensitivity when a single antigen was employed. The results of a receiver operator characteristic analysis revealed that a cocktail ELISA using all five antigens was significantly more sensitive (77.8%) than the use of a single antigen and offered equivalent specificity; moreover, it produced the largest area under the curve (0.91 versus 0.55 to 0.87). Therefore, a cocktail ELISA containing abundantly expressed antigens enhances the sensitivity of a single antigen and can be a useful diagnostic tool for the detection of active TB.