Viscosity-Controllable Graphene Oxide Colloids Using Electrophoretically Deposited Graphene Oxide Sheets.

Graphene oxide (GO) is one of the interesting ink materials owing to its fascinating properties, such as high dissolubility in water and high controllable electric properties. For versatile printing application, the viscosity of GO colloids should be controlled in order to meet the specific process requirements. Here, we report on the relatively rapid fabrication of viscosity-increased GO (VIGO) colloids mixed with electrophoretically deposited GO sheets (EPD-GO). As the GO colloid concentration, applied voltage, and deposition time increase, the viscosity of the GO colloids becomes high. The reason for the improved viscosity of GO colloids is because EPD-GO has parallel stacked GO sheets. The GO and VIGO colloids are compared and characterized using various chemical and structural analyzers. Consequently, our simple and fast method for the fabrication of GO colloids with enhanced viscosity can be used for producing inks for flexible and printed electronics.

A common intronic variant of CXCR3 is functionally associated with gene expression levels and the polymorphic immune cell responses to stimuli.

BACKGROUND: CXCR3 is a chemokine receptor that plays important roles in mediating chemotactic signals and modulating the activation of lymphocytes. We have previously conducted a case-control study by using a candidate gene approach to investigate the association of CXCR3 polymorphisms with the risk of asthma. Results from the epidemiologic study showed that a common nucleotide variant in the CXCR3 intron (rs2280964G>A) was associated with disease susceptibility (1006 cases and 384 control subjects; odds ratio, 0.81; 95% CI, 0.69-0.94; P = .007). OBJECTIVE: The aim of our study was to evaluate the epidemiologic study and provide functional evidence for the association of rs2280964G>A with asthma by investigating the effects of intronic variant on chemokine-mediated phenotypes of human-derived T cells. METHODS: We used cell line-based in vitro and human primary T cell-based ex vivo studies to examine the functional consequences of the intronic polymorphism, focusing on the regulation of gene expression, splicing, and immune responsiveness toward activating signals. RESULTS: We present functional evidence indicating that the rs2280964A allele significantly correlates with decreased CXCR3 gene expression, which would lead to variation in immune cell responses to chemokine-cytokine signals in vitro and ex vivo that includes a decrease in chemotactic activity. CONCLUSION: These findings, in conjunction with those of our previous epidemiologic studies, might implicate a functional link between a common nucleotide variant of a chemokine receptor gene, CXCR3, and a cause for a complex-trait disease, asthma.

Genome-wide profiling of antigen-induced time course expression using murine models for acute and chronic asthma.

BACKGROUND: Asthma is a complex-trait disease caused by complicated interactions among multiple genetic and environmental risk factors. The clinical symptoms of asthma, such as periodic airway obstruction, hyperresponsiveness and mucus hypersecretion, are mediated by acute and chronic bronchial inflammation. METHODS: To better understand the mechanisms by which allergen-induced acute inflammation leads to chronic asthma accompanied by irreversible airway remodeling, we analyzed time course transcriptional responses in the lungs of model mice that were exposed to aerosolized ovalbumin for up to 9 weeks after an initial sensitization. RESULTS: We observed increased levels of total plasma IgE and histological changes in lung tissues from the ovalbumin-treated mice, which is consistent with the typical inflammatory phenotypes of asthma pathogenesis. Our oligonucleotide microarray analyses revealed a total of 776 differentially expressed genes induced by antigenic challenge (> or =1.5-fold change, p < 0.05). Of these genes, most of the immune-responsive genes were transiently up-regulated in the early phase of the allergen treatment (within a week) with a concomitant up-regulation of genes involved in mucus production. These genes were not differentially regulated in the mice challenged for a longer period of time (up to 6 weeks). We also identified some of the genes implicated in extracellular matrix remodeling, for which the time course expression did not necessarily coincide with the expression patterns of immune-responsive genes. CONCLUSION: Our data suggest that there is a complex interregulatory genetic network associated with the structural changes that accompany the progression of the allergic inflammatory reaction in chronic asthma.

pHP489, a Helicobacter pylori small cryptic plasmid, harbors a novel gene coding for a replication initiation protein.

We have analyzed a Helicobacter pylori plasmid, pHP489. The 1222-bp nucleotide sequence had one open reading frame, a DnaA-binding site, one direct repeat, and three inverted repeats. The (G+C) content of pHP489 was 33.3%. Although the nucleic acid sequence and deduced amino acid sequence were homologous to those of other bacterial plasmid Rep proteins, the degree of similarity was very low. A deletion analysis showed that the Rep protein was not required for the replication of pHP489 in its H. pylori host, but the host replication machinery was needed.

Identifying the major proteome components of Helicobacter pylori strain 26695.

The whole genome sequences of Helicobacter pylori strain 26695 have been reported. Whole cell proteins of H. pylori strain 26695 cells were obtained and analyzed by two-dimensional electrophoresis, using immobilized pH gradient strips. The most abundant proteins were shown in the region of pI 4.0-9.5 with molecular masses from 10 to 100 kDa. Soluble proteins were precipitated by the use of 0-80% saturated solutions of ammonium sulfate. Soluble proteins precipitated by the 0-40% saturations of ammonium sulfate produced similar spot profiles and their abundant protein spots had acidic pI regions. However, a number of soluble proteins precipitated by more than 60% saturation of ammonium sulfate were placed in the alkaline pI regions, compared to those precipitated by 40% saturation. In addition, we have performed an extensive proteome analysis of the strain utilizing peptide MALDI-TOF-MS. Among the 345 protein spots processed, 175 proteins were identified. The identified spots represented 137 genes. One-hundred and fifteen proteins were newly identified in this study, including DNA polymerase III beta-subunit. These results might provide guidance for the enrichment of H. pylori proteins and contribute to construct a master protein map of H. pylori.

Characterization of a small cryptic plasmid, pHP51, from a Korean isolate of strain 51 of Helicobacter pylori.

The nucleotide sequence of a 3955-bp Helicobacter pylori plasmid, pHP51 was determined, and two open reading frames, ORF1 and ORF2, were identified. The deduced amino acid sequence of ORF1 was highly conserved (87-89%) among plasmid replication initiation proteins, RepBs. The function of ORF2 was not assigned because it lacked known functional domains or sequence similarity with other known proteins, although it had a HPFXXGNG motif that was also found in the cAMP-induced filamentation (fic) gene. Three kinds of repeats were present on the plasmid outside of the ORFs, including the R1 and R2 repeats that are common in H. pylori plasmids. One 100-bp sequence detected in the noncoding region of pHP51 was highly similar to the genomic sequence of H. pylori 26695.