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Helicobacter pylori infection causes a variety of gastrointestinal diseases, including peptic ulcers and gastric cancer. Its colonization of the gastric mucosa of the human stomach is a prerequisite for survival in the stomach. Colonization depends on its motility, which is facilitated by the helical shape of the bacterium. In H. pylori, cross-linking relaxation or trimming of peptidoglycan muropeptides affects the helical cell shape. Csd4 has been identified as one of the cell shape-determining peptidoglycan hydrolases in H. pylori. It is a Zn2+-dependent D,L-carboxypeptidase that cleaves the bond between the γ-D-Glu and the mDAP of the non-cross-linked muramyltripeptide (muramyl-L-Ala-γ-D-Glu- mDAP) of the peptidoglycan to produce the muramyldipeptide (muramyl-L-Ala-γ-D-Glu) and mDAP. Here, the crystal structure of H. pylori Csd4 (HP1075 in strain 26695) is reported in three different states: the ligand-unbound form, the substrate-bound form and the product-bound form. H. pylori Csd4 consists of three domains: an N-terminal D,L-carboxypeptidase domain with a typical carboxypeptidase fold, a central β-barrel domain with a novel fold and a C-terminal immunoglobulin-like domain. The D,L-carboxypeptidase domain recognizes the substrate by interacting primarily with the terminal mDAP moiety of the muramyltripeptide. It undergoes a significant structural change upon binding either mDAP or the mDAP-containing muramyltripeptide. It it also shown that Csd5, another cell-shape determinant in H. pylori, is capable of interacting not only with H. pylori Csd4 but also with the dipeptide product of the reaction catalyzed by Csd4. [ABSTRACT FROM AUTHOR]

Abstract: With the availability of plant genome sequencing, analysis of plant proteins with mass spectrometry has become promising and admired. Determining the proteome of a cell is still a challenging assignment, which is convoluted by proteome dynamics and convolution. Chloroplast is fastidious curiosity for plant biologists due to their intricate biochemical pathways for indispensable metabolite functions. In this review, an overview on proteomic studies conducted in wheat with a special focus on subcellular proteomics of chloroplast, salt and water stress. In recent years, we and other groups have attempted to understand the photosynthesis in wheat and abiotic stress under salt imposed and water deficit during vegetative stage. Those studies provide interesting results leading to better understanding of the photosynthesis and identifying the stress-responsive proteins. Indeed, recent studies aimed at resolving the photosynthesis pathway in wheat. Proteomic analysis combining two complementary approaches such as 2-DE and shotgun methods couple to high through put mass spectrometry (LTQ-FTICR and MALDI-TOF/TOF) in order to better understand the responsible proteins in photosynthesis and abiotic stress (salt and water) in wheat chloroplast will be focused. Biological significance: In this review we discussed the identification of the most abundant protein in wheat chloroplast and stress-responsive under salt and water stress in chloroplast of wheat seedlings, thus providing the proteomic view of the events during the development of this seedling under stress conditions. Chloroplast is fastidious curiosity for plant biologists due to their intricate biochemical pathways for indispensable metabolite functions. An overview on proteomic studies conducted in wheat with a special focus on subcellular proteomics of chloroplast, salt and water stress. We have attempted to understand the photosynthesis in wheat and abiotic stress under salt imposed and water deficit during seedling stage. Those studies provide interesting results leading to a better understanding of the photosynthesis and identifying the stress-responsive proteins. In reality, our studies aspired at resolving the photosynthesis pathway in wheat. Proteomic analysis united two complementary approaches such as Tricine SDS-PAGE and 2-DE methods couple to high through put mass spectrometry (LTQ-FTICR and MALDI-TOF/TOF) in order to better understand the responsible proteins in photosynthesis and abiotic stress (salt and water) in wheat chloroplast will be highlighted. This article is part of a Special Issue entitled: Translational Plant Proteomics. [Copyright &y& Elsevier]

Abstract: We employed stable isotope probing (SIP) with 13C-labeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to identify active microorganisms responsible for RDX biodegradation in groundwater microcosms. Sixteen different 16S rRNA gene sequences were derived from microcosms receiving 13C-labeled RDX, suggesting the presence of microorganisms able to incorporate carbon from RDX or its breakdown products. The clones, residing in Bacteroidia, Clostridia, α-, β- and δ-Proteobacteria, and Spirochaetes, were different from previously described RDX degraders. A parallel set of microcosms was amended with cheese whey and RDX to evaluate the influence of this co-substrate on the RDX-degrading microbial community. Cheese whey stimulated RDX biotransformation, altered the types of RDX-degrading bacteria, and decreased microbial community diversity. Results of this study suggest that RDX-degrading microorganisms in groundwater are more phylogenetically diverse than what has been inferred from studies with RDX-degrading isolates. [Copyright &y& Elsevier]

Mulitpotent mesenchymal stem cells (MSCs) derived from human bone marrow are promising candidates for the development of cell therapeutic strategies. MSC surface protein profiles provide novel biological knowledge concerning the proliferation and differentiation of these cells, including the potential for identifying therapeutic targets. Basic fibroblast growth factor (bFGF) affects cell surface proteins, which are associated with increased growth rate, differentiation potential, as well as morphological changes of MSCs in vitro. Cell surface proteins were isolated using a biotinylation-mediated method and identified using a combination of one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry. The resulting gel lines were cut into 20 bands and digested with trypsin. Each tryptic fragment was analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry. Proteins were identified using the Mascot search program and the International Protein Index human database. Noble MSC surface proteins ( n = 1,001) were identified from cells cultured either with ( n = 857) or without ( n = 667) bFGF-containing medium in three independent experiments. The proteins were classified using FatiGO to elucidate their function. We also confirmed the proteomics results using Western blotting and immunofluorescence microscopic analysis. The nature of the proteins identified makes it clear that MSCs express a wide variety of signaling molecules, including those related to cell differentiation. Among the latter proteins, four Ras-related Rab proteins, laminin-R, and three 14-3-3 proteins that were fractionated from MSCs cultured on bFGF-containing medium are implicated in bFGF-induced signal transduction of MSCs. Consequently, these finding provide insight into the understanding of the surface proteome of human MSCs. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Leaves are the final site of salinity perception through the roots. To better understand how wheat chloroplasts proteins respond to salt stress, the study aimed to the physiochemical and comparative proteomics analysis. Seedlings (12-days-old) were exposed to 150 mM NaCl for 1, 2, or 3 days. Na ions were rapid and excessively increase in roots, stems and leaves. Photosynthesis and transpiration rate, stomatal conductance, and relative water content decreased whereas the level of proline increased. Statistically significant positive correlations were found among the content of hydrogen peroxide, activity of catalase, and superoxide dismutase under salt stress in wheat. Protein abundance within the chloroplasts was examined by two-dimensional electrophoresis. More than 100 protein spots were reproducibly detected on each gel, 21 protein spots were differentially expressed during salt treatment. Using linear quadruple trap-Fourier transform ion cyclotron resonance (LTQ-FTICR) hybrid mass spectrometry, 65 unique proteins assigned in the differentially abundant spots. Most proteins were up-regulated at 2 and 3 days after being down-regulated at 1 day. Others showed only slight responses after 3 days of treatment, including Rubisco, glutamate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, isocitrate dehydrogenase, photosystem I, and pyridoxal biosynthesis protein PDX1.2 and PDX1.3. The ATP synthase (α, β, and γ) and V-type proton ATPase subunits were down-regulated resulting showed negative impact by Na on the photosynthetic machinery. This ephemeral increase and subsequent decrease in protein contents may demonstrate a counterbalancing influence of identified proteins. Several proteins such as cytochrome b6-f (Cyt b6-f), germin-like-protein, the γ-subunit of ATP synthase, glutamine synthetase, fructose-bisphosphate aldolase, S-adenosylmethionine synthase, carbonic anhydrase were gradually up-regulated during the period of treatment, which can be identified as marker proteins. [ABSTRACT FROM AUTHOR]

We utilized Percoll density gradient centrifugation to isolate and fractionate chloroplasts of Korean winter wheat cultivar cv. Kumgang ( Triticum aestivum L.). The resulting protein fractions were separated by one dimensional polyacrylamide gel electrophoresis (1D-PAGE) coupled with LTQ-FTICR mass spectrometry. This enabled us to detect and identify 767 unique proteins. Our findings represent the most comprehensive exploration of a proteome to date. Based on annotation information from the UniProtKB/Swiss-Prot database and our analyses via WoLF PSORT and PSORT, these proteins are localized in the chloroplast (607 proteins), chloroplast stroma (145), thylakoid membrane (342), lumens (163), and integral membranes (166). In all, 67% were confirmed as chloroplast thylakoid proteins. Although nearly complete protein coverage (89% proteins) has been accomplished for the key chloroplast pathways in wheat, such as for photosynthesis, many other proteins are involved in regulating carbon metabolism. The identified proteins were assigned to 103 functional categories according to a classification system developed by the iProClass database and provided through Protein Information Resources. Those functions include electron transport, energy, cellular organization and biogenesis, transport, stress responses, and other metabolic processes. Whereas most of these proteins are associated with known complexes and metabolic pathways, about 13% of the proteins have unknown functions. The chloroplast proteome contains many proteins that are localized to the thylakoids but as yet have no known function. We propose that some of these familiar proteins participate in the photosynthetic pathway. Thus, our new and comprehensive protein profile may provide clues for better understanding that photosynthetic process in wheat. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Recent studies have reported the color change and formation of precipitates containing para-chloroaniline (PCA) after a reaction of sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Alexidine (ALX), a biguanide disinfectant similar to CHX, has greater affinity for bacterial virulence factors than CHX. This study determined by electrospray ionization mass spectrometry (ESI-MS) and scanning electron microscopy (SEM) whether the chemical interaction between ALX and NaOCl results in PCA or precipitates. Methods: ESI-MS was performed on 4 different concentrations of ALX (1%, 0.5%, 0.25%, and 0.125%) with 4% NaOCl to detect the presence of PCA. As control groups, 1% ALX, 0.5% PCA, and a mixture of 2% CHX and 4% NaOCl were analyzed. The formation of precipitates on the dentinal surfaces of premolar root canals treated with the solutions of ALX and NaOCl (AN) or CHX and NaOCl (CN) was observed by SEM and the color change in the reaction solutions was also analyzed. Results: ESI-MS showed that the peak (mass/charge ratio = 128.026) in the PCA spectrum was not detected in any of the 4 AN solutions, whereas the peak was found in the CN solution. SEM revealed precipitates covering dentinal surfaces in the CN solution. The AN solutions produced no precipitate. The AN solutions changed in color from light yellow to transparent with decreasing ALX concentration, whereas peach-brown discoloration was observed in the CN solution. Conclusions: The interaction of ALX and NaOCl did not produce PCA or precipitates, and the color of the reacted solution changed transparent with decreasing ALX concentration. [Copyright &y& Elsevier]

The objective of this study is the systematic and individual assessment of the annual effective dose due to inhaled radon for the Seoul Subway Police officers, Korea. The annual average radon concentrations were found to be in the range of 18.9–114 Bq·m−3 in their workplaces. The total annual effective doses which may likely to be received on duty were assessed to be in the range of 0.41–1.64 mSv·y−1. These were well below the recommended action level 10 mSv·y−1 by ICRP. However, the effective doses were higher than subway station staff in Seoul, Korea. [ABSTRACT FROM PUBLISHER]

Abstract: It is a generally accepted result that the inclusion of rubber particles causes the concrete to degrade physical properties of the concrete. In this study the crumb rubber was partially oxidized and used as additives of mortars. Dramatically, the compressive strength of the rubberized mortars (with 6wt.%) was greater than that of mortars without the crumb rubber. To understand these phenomena, Fourier Transform Infrared Spectroscopy (FTIR) was used to explore the functional groups on surfaces of the crumb rubber, and Scanning Electron Microscopy (SEM) was used to observe microstructures of mortars. With the partial oxidation treatment, rubber surfaces produced hydrophilic functional groups as indicated by IR spectra and the hydration of the cement near the crumb rubber was enhanced as shown by SEM, leading to stronger mortars. [ABSTRACT FROM AUTHOR]

Abstract: Triphenylamine-based novel diamine monomers with side group, such as 4-(2,2′-bithiophenyl)-4′,4″-diaminotriphenylamine (2TTPA) and 4-(3,5-bis(trifluoromehyl)phenyl)-4′,4″-diaminotriphenylamine (6FTPA) were prepared and used for polyimide synthesis. 4-Bromo-dinitrotriphenylamine (BrTPA), prepared from 4-bromoaniline and 1-fluoro-4-nitrobenzene, was reacted with 2,2′-bithiophenene-5-boronic acid (2TBB) or 3,5-bis(trifluoromethyl)benzeneboronic acid (6FBB), followed by hydrogenation to afford 2TTPA and 6FTPA, respectively. After characterization by FT-IR, 1H-NMR, EA and melting point analyzer, the triphenylamine-based dimaines were utilized to prepare polyimides with 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) or 2,2-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA). The polymers were characterized by FT-IR and 1H-NMR. Thermal, optical and electrical properties were also evaluated by DSC/TGA, UV–vis/photoluminescence spectrometery and cyclic voltammetry (CV), respectively. The 6FDA–6FTPA polyimide exhibited high glass transition temperatures (291°C), high thermal stability (>488°C) and light blue emission (480nm) with very good solubility even after imidization. [ABSTRACT FROM AUTHOR]