The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Matthias Wagner - One of the best experts on this subject based on the ideXlab platform.
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steric shielding vs structural constraint in a boron containing polycyclic Aromatic Hydrocarbon
Organometallics, 2017Co-Authors: Valentin M Hertz, Naoki Ando, Masato Hirai, Michael Bolte, Hans-wolfram Lerner, Shigehiro Yamaguchi, Matthias WagnerAbstract:The highly reactive boron-doped polycyclic Aromatic Hydrocarbon 8H-8-bromo-8-borabenzo[gh]tetraphene has been synthesized via a multistep sequence encompassing a Peterson olefination, a stilbene-type photocyclization, and an Si/B exchange reaction. The compound was subsequently treated with mesityllithium to give the derivative 3 or with [2,6-bis(propen-2-yl)phenyl]lithium to furnish the intermediate 4. A scandium(III) triflate mediated Friedel–Crafts reaction transformed 4 into the rigid, planarized triarylborane 5. Compounds 3 and 5 are both inert toward air and moisture but are still able to bind fluoride ions, where the affinity of 3 in CHCl3 is higher than that of 5. Both arylboranes are yellow solids, and their solutions exhibit an intense blue fluorescence (ΦPL = 85% (3), 89% (5)). According to cyclic voltammetry, reversible reduction occurs at half-wave potentials of E1/2 = −2.05 V (3) and −2.14 V (5; in THF, vs FcH/FcH+). The crystal lattices consist of π-stacked dimers, arranged in herringbone p...
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Steric Shielding vs Structural Constraint in a Boron-Containing Polycyclic Aromatic Hydrocarbon
2016Co-Authors: Valentin M. Hertz, Naoki Ando, Masato Hirai, Michael Bolte, Hans-wolfram Lerner, Shigehiro Yamaguchi, Matthias WagnerAbstract:The highly reactive boron-doped polycyclic Aromatic Hydrocarbon 8H-8-bromo-8-borabenzo[gh]tetraphene has been synthesized via a multistep sequence encompassing a Peterson olefination, a stilbene-type photocyclization, and an Si/B exchange reaction. The compound was subsequently treated with mesityllithium to give the derivative 3 or with [2,6-bis(propen-2-yl)phenyl]lithium to furnish the intermediate 4. A scandium(III) triflate mediated Friedel–Crafts reaction transformed 4 into the rigid, planarized triarylborane 5. Compounds 3 and 5 are both inert toward air and moisture but are still able to bind fluoride ions, where the affinity of 3 in CHCl3 is higher than that of 5. Both arylboranes are yellow solids, and their solutions exhibit an intense blue fluorescence (ΦPL = 85% (3), 89% (5)). According to cyclic voltammetry, reversible reduction occurs at half-wave potentials of E1/2 = −2.05 V (3) and −2.14 V (5; in THF, vs FcH/FcH+). The crystal lattices consist of π-stacked dimers, arranged in herringbone patterns. Importantly, 3 and 5 share nearly identical properties, despite possessing fundamentally different structures
Lin Cheng - One of the best experts on this subject based on the ideXlab platform.
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Aromatic Hydrocarbon receptor provides a link between smoking and rheumatoid arthritis in peripheral blood mononuclear cells
Clinical and Experimental Rheumatology, 2019Co-Authors: Lin Cheng, Long Qian, Zhouzhou XuAbstract:Objectives Epidemiology shows that smoking plays a central role in rheumatoid arthritis (RA). The aim of this study was to evaluate the potential relationship between smoking, Aromatic Hydrocarbon receptor (AHR) and RA susceptibility. Methods We performed a hospital-based, case-control study of patients with RA and healthy controls. Expressions of AHR, cytochrome P4501A1(CYP1A1), Aromatic Hydrocarbon receptor repressor (AHRR) genes were assessed in peripheral blood mononuclear cells (PBMCs) and cultured cells using real-time PCR. The response of PBMCs to the AHR agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and cigarette smoke extract (CSE) were cultured in vitro. Results AHR and its downstream gene expressions were demonstrated in smoking rheumatoid PBMCs and non-smoking patients with significantly higher expression in smoking patients. The observation was consistent with the sensitivity of RA PBMCs to TCDD and CSE stimulation demonstrated in vitro. Conclusions Our study shows that smoking may be involved in the pathogenesis of RA by the AHR pathway.
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genetic association of Aromatic Hydrocarbon receptor and its repressor gene polymorphisms with risk of rheumatoid arthritis in han chinese populations
Medicine, 2017Co-Authors: Lin Cheng, Guosheng Wang, Xiaomei Li, Long Qian, Xiangpei LiAbstract:: The goal of this study was to evaluate the potential relationship among polymorphisms of Aromatic Hydrocarbon receptor, Aromatic Hydrocarbon receptor repressor, and rheumatoid arthritis (RA) susceptibility as well as the association among the polymorphisms of Aromatic Hydrocarbon receptor, Aromatic Hydrocarbon receptor repressor, and their expression.We performed a hospital-based, case-control study of 400 patients with RA and 726 healthy controls in Han Chinese populations. Two single-nucleotide polymorphisms were selected for genotyping including Aromatic Hydrocarbon receptor (rs2066853) and Aromatic Hydrocarbon receptor repressor (rs2292596).To single-nucleotide polymorphism rs2292596, a statistically significantly increased risk of RA was found to be associated with the G allele of rs2292596; the odds ratio was 2.170 (95% confidence interval: 1.820-2.587). Unfortunately, no significant differences exhibited in the allelic and the genotype frequencies of rs2066853 between 2 groups. We failed to find any association between rs2066853, rs2292596 genotypes and their expression of patients, respectively. No statistical relationship was found between Aromatic Hydrocarbon receptor, Aromatic Hydrocarbon receptor repressor at messenger Ribonucleic acid levels and clinical data, either.This study demonstrated that the polymorphisms of rs2292596 was significant with genetic susceptibility to RA patients; furthermore, it suggests the G allele of rs2292596 might be associated with a dangerous effect on RA in Han Chinese populations.
A B Orth - One of the best experts on this subject based on the ideXlab platform.
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the camp signal transduction pathway mediates resistance to dicarboximide and Aromatic Hydrocarbon fungicides in ustilago maydis
Fungal Genetics and Biology, 2001Co-Authors: Marilee Ramesh, A B Orth, David R Laidlaw, Franz Durrenberger, James W KronstadAbstract:The cAMP signal transduction pathway mediates the switch between yeast-like and filamentous growth and influences both sexual development and pathogenicity in the smut fungus Ustilago maydis. Signaling via cAMP may also play a role in fungicide resistance in U. maydis. In particular, the adr1 gene, which encodes the catalytic subunit of the U. maydis cAMP-dependent protein kinase (PKA), is implicated in resistance to the dicarboximide and Aromatic Hydrocarbon fungicides. In this study, we examined the sensitivity of PKA to vinclozolin and could not demonstrate direct inhibition of protein kinase activity. However, we did find that mutants with disruptions in the ubc1 gene, which encodes the regulatory subunit of PKA, were resistant to both vinclozolin and chloroneb. We also found that these fungicides altered the morphology of both wild-type and ubc1 mutant cells. In addition, strains that are defective in ubc1 display osmotic sensitivity, a property often associated with vinclozolin and chloroneb resistance in other fungi.
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characterization and genetic analysis of laboratory mutants of ustilago maydis reistant to dicarboximide and Aromatic Hydrocarbon fungicides
Phytopathology, 1994Co-Authors: A B Orth, A Sfarra, Eva J Pell, Ming TienAbstract:Mutants of Ustilago maydis resistant to dicarboximide (DCOF) and Aromatic Hydrocarbon fungicides (AHF) were isolated after chemical mutagenesis or by selection of spontaneous mutants on fungicide-amended agar medium. A wide range of mutants, with low to high levels of resistance, were isolated. The resistance factor compared to the wild type was greater than 150 for three mutants isolated on tolclophos-methyl and greater than 50 for three mutants isolated on vinclozolin. Growth rates for these six most tolerant isolates were similar to that of the wild type. The phenomenon of cross-resistance between these two groups was confirmed. None of the mutants were resistant to the ergosterol biosynthesis inhibitor propiconazole. Two mutants, VR43 and VR44, demonstrated the same osmotic sensitivity when grown in the presence of NaCl (1-8%) as the wild type under these conditions
Zhouzhou Xu - One of the best experts on this subject based on the ideXlab platform.
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Aromatic Hydrocarbon receptor provides a link between smoking and rheumatoid arthritis in peripheral blood mononuclear cells
Clinical and Experimental Rheumatology, 2019Co-Authors: Lin Cheng, Long Qian, Zhouzhou XuAbstract:Objectives Epidemiology shows that smoking plays a central role in rheumatoid arthritis (RA). The aim of this study was to evaluate the potential relationship between smoking, Aromatic Hydrocarbon receptor (AHR) and RA susceptibility. Methods We performed a hospital-based, case-control study of patients with RA and healthy controls. Expressions of AHR, cytochrome P4501A1(CYP1A1), Aromatic Hydrocarbon receptor repressor (AHRR) genes were assessed in peripheral blood mononuclear cells (PBMCs) and cultured cells using real-time PCR. The response of PBMCs to the AHR agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and cigarette smoke extract (CSE) were cultured in vitro. Results AHR and its downstream gene expressions were demonstrated in smoking rheumatoid PBMCs and non-smoking patients with significantly higher expression in smoking patients. The observation was consistent with the sensitivity of RA PBMCs to TCDD and CSE stimulation demonstrated in vitro. Conclusions Our study shows that smoking may be involved in the pathogenesis of RA by the AHR pathway.
James W Kronstad - One of the best experts on this subject based on the ideXlab platform.
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the camp signal transduction pathway mediates resistance to dicarboximide and Aromatic Hydrocarbon fungicides in ustilago maydis
Fungal Genetics and Biology, 2001Co-Authors: Marilee Ramesh, A B Orth, David R Laidlaw, Franz Durrenberger, James W KronstadAbstract:The cAMP signal transduction pathway mediates the switch between yeast-like and filamentous growth and influences both sexual development and pathogenicity in the smut fungus Ustilago maydis. Signaling via cAMP may also play a role in fungicide resistance in U. maydis. In particular, the adr1 gene, which encodes the catalytic subunit of the U. maydis cAMP-dependent protein kinase (PKA), is implicated in resistance to the dicarboximide and Aromatic Hydrocarbon fungicides. In this study, we examined the sensitivity of PKA to vinclozolin and could not demonstrate direct inhibition of protein kinase activity. However, we did find that mutants with disruptions in the ubc1 gene, which encodes the regulatory subunit of PKA, were resistant to both vinclozolin and chloroneb. We also found that these fungicides altered the morphology of both wild-type and ubc1 mutant cells. In addition, strains that are defective in ubc1 display osmotic sensitivity, a property often associated with vinclozolin and chloroneb resistance in other fungi.