Summary
Laccases are oxidases that contain several copper atoms, and catalyse single‐electron oxidations of phenolic compounds with concomitant reduction of oxygen to water. The enzymes are ...particularly widespread in ligninolytic basidiomycetes, but also occur in certain prokaryotes, insects and plants. Depending on the species, laccases are involved in various biosynthetic processes contributing to carbon recycling in land ecosystems and the morphogenesis of biomatrices, wherein low‐molecular‐weight naturally occurring phenols serve as key enzyme substrates. Studies of these in vivo synthetic pathways have afforded new insights into fungal laccase applicability in green synthetic chemistry. Thus, we here review fungal laccase‐catalysed oxidations of naturally occurring phenols that are particularly relevant to the synthesis of fine organic chemicals, and we discuss how the discovered synthetic strategies mimic laccase‐involved in vivo pathways, thus enhancing the green nature of such reactions. Laccase‐catalysed in vivo processes yield several types of biopolymers, including those of cuticles, lignin, polyflavonoids, humus and the melanin pigments, using natural mono‐ or poly‐phenols as building blocks. The in vivo synthetic pathways involve either phenoxyl radical‐mediated coupling or cross‐linking reactions, and can be adapted to the design of in vitro oxidative processes involving fungal laccases in organic synthesis; the laccase substrates and the synthetic mechanisms reflect in vivo processes. Notably, such in vitro synthetic pathways can also reproduce physicochemical properties (e.g. those of chromophores, and radical‐scavenging, hydration and antimicrobial activities) found in natural biomaterials. Careful study of laccase‐associated in vivo metabolic pathways has been rewarded by the discovery of novel green applications for fungal laccases. This review comprehensively summarizes the available data on laccase‐catalysed biosynthetic pathways and associated applications in fine chemical syntheses.
Controversies exist with regard to in vivo approaches to delayed immunologically mediated adverse drug reactions, such as exanthem (maculopapular eruption), drug reaction with eosinophilia and ...systemic symptoms, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome/toxic epidermal necrolysis, and fixed drug eruptions. In particular, widespread differences exist between regions and practice on the availability and use of intradermal and patch testing, the standard drug concentrations used, the use of additional drugs in intradermal and patch testing to help determine cross-reactivity, the timing of testing in relation to the occurrence of the adverse drug reaction, the use of testing in specific phenotypes, and the use of oral challenge in conjunction with delayed intradermal and patch testing to ascertain drug tolerance. It was noted that there have been advances in the science of delayed T cell–mediated reactions that have shed light on immunopathogenesis and provided a mechanism of preprescription screening in the case of HLA-B*57:01 and abacavir hypersensitivity and HLA-B*15:02 and carbamazepine Stevens-Johnson syndrome/toxic epidermal necrolysis in Southeast Asian subjects. Future directions should include the collaboration of large international networks to develop and standardize in vivo diagnostic approaches, such as skin testing and patch testing, combined with ex vivo and in vitro laboratory approaches.
Engineered nanomaterials (ENMs) enable the control and exploration of intermolecular interactions inside microscopic systems, but the potential environmental impacts of their inevitable release ...remain largely unknown. Plants exposed to ENMs display effects, such as increase in biomass and chlorophyll, distinct from those induced by exposure to their bulk counterparts, but few studies have addressed the mechanisms underlying such physiological results. The current investigation found that exposure of Arabidopsis thaliana to nano zerovalent iron (nZVI) triggered high plasma membrane H+-ATPase activity. The increase in activity caused a decrease in apoplastic pH, an increase in leaf area, and also wider stomatal aperture. Analysis of gene expression indicated that the levels of the H+-ATPase isoform responsible for stomatal opening, AHA2, were 5-fold higher in plants exposed to nZVI than in unexposed control plants. This is the first study to show that nZVI enhances stomatal opening by inducing the activation of plasma membrane H+-ATPase, leading to the possibility of increased CO2 uptake.
Cough is an essential defence mechanism 1. However, chronic cough is a significant cause of morbidity, seriously impairing quality of life 2. Previously, chronic cough was considered a consequence of ...various diseases, such as asthma/eosinophilic bronchitis, rhinitis and gastro-oesophageal acid reflux disease 3, 4. Recent evidence, however, suggests that chronic cough is a clinical syndrome with distinct intrinsic pathophysiology characterised by neuronal hypersensitivity 5-7. Here, we estimated the worldwide epidemiological burden of chronic cough irrespective of putative diagnosis in general adult populations using a comprehensive systematic literature review.
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•Fe(II)-chitosan/alginate composite was fabricated to activate persulfate.•The material showed a higher removal of bisphenol A than Fe(II) with persulfate.•The released Fe ions was ...readsorbed to the material after reaction with persulfate.•The system maintained efficiency at wide pH and in the presence of various anions.
In this study, a novel Fe(II) immobilized chitosan/alginate composite (Fe-Chitoal) was prepared via a simple crosslinking reaction to activate persulfate (PS) to degrade bisphenol A (BPA). The newly synthesized Fe-Chitoal was characterized by scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, which indicated that Fe was successfully imprinted into the composite. The PS/Fe-Chitoal system demonstrated a much higher removal efficiency of BPA (99.5%) than the conventional PS/Fe(II) system (69.2%) with a negligible amount of Fe ions released into the solution. The effects of different experimental conditions, including the concentration of PS, concentration of Fe-Chitoal, and pH, on the removal of BPA were also investigated. The removal rate increased with increasing amounts of PS and Fe-Chitoal, and a high removal efficiency was maintained at a pH of 2–10. The PS/Fe-Chitoal system was rarely affected by high concentrations of anions (Cl−, SO42−, NO3−, and HCO3−), and the composite catalyst could be reused in a synthetic sewage solution. To simply separate the material, a Fe-Chitoal mesh bag was fabricated, which showed a consistent catalytic reactivity toward PS and BPA removal suggesting practical field applications.
Background
The effect of novel tobacco products, such as electronic cigarettes (EC) and heated tobacco products (HTP), on allergic rhinitis (AR) and asthma is not well known.
Objective
To evaluate ...the health effect of novel tobacco products on asthma and AR.
Methods
This study was conducted using large survey data on Korean middle and high school students. The relationship between current asthma/AR and novel tobacco products user status was evaluated. In order to compare the combined effects of conventional cigarette (CC), EC, and HTP use on current allergic diseases, the participants were classified into 18 groups based on CC (current, former, and never), EC (current, former, and never), and HTP (ever and never) status.
Results
A total of 60,040 participants representing 2,850,118 Korean adolescents were analyzed. Of all participants, 6.7%, 2.7%, and 2.9% were current CC, current EC, and ever HTP users, respectively. Current CC and ever HTP use was significantly associated with current asthma and AR in adjusted models. Current EC showed association with current AR but the association with asthma disappeared in the adjusted model. Among 18 groups, the groups including current CC use showed higher risk of current AR and asthma than never HTP‐never EC‐never CC group. The odds ratio of current asthma especially increased more in those who used EC and/or HTP with CC concurrently than those in the never HTP‐never EC‐current CC user group.
Conclusion
Using EC and/or HTP in adolescents might enhance the adverse effect of CC on AR and asthma.
Among Korean adolescents aged from 12 to 18 years old, 6.7% and 2.7% currently use conventional cigarettes and electronic cigarettes, respectively and 2.9% ever used heated tobacco products. The use of conventional cigarette, electronic cigarette, and heated tobacco product, respectively and in combination increases the risk of allergic rhinitis and asthma in Korean adolescents. The use of heated tobacco product especially enhances the impact of conventional cigarettes on allergic rhinitis and asthma.
As a result of extensive research efforts by several research groups, magnetite-based materials have gained enormous attention in diverse fields including biomedicine, catalysis, energy and data ...storage devices, magnetic resonance imaging, and environmental remediation. Owing to their low production cost, ease of modification, biocompatibility, and superparamagnetism, the use of these materials for the abatement of environmental toxicants has been increasing continuously. Here we focus on the recent advances in the use of magnetite-based adsorbents for removal of radionuclides (such as
137
Cs(
i
),
155
Eu(
iii
),
90
Sr(
ii
),
238
U(
vi
),
etc.
) from diverse aqueous phases. This review summarizes the preparation and surface modification of magnetite-based adsorbents, their physicochemical properties, adsorption behavior and mechanism, and diverse conventional and recent environmental technological options for the treatment of water contaminated with radionuclides. In addition, case studies for the removal of radionuclides from actual contaminated sites are discussed, and finally the optimization of magnetite-based remedial solutions is presented for practical application.
As a result of extensive research efforts by several research groups, magnetite-based materials have gained enormous attention in diverse fields.
In this study, we investigated the effect of nZVI on plant root elongation in Arabidopsis thaliana and showed, for the first time, that nZVI enhanced root elongation by inducing OH radical-induced ...cell wall loosening. Exposure of plants to 0.5 g/L nZVI enhanced root elongation by 150–200% over that in the control, and further mechanistic studies showed that this occurred via nZVI-mediated OH radical-induced cell wall loosening. The oxidation capacity of nZVI, leading to release of H2O2, allowed it to cause OH radical-induced cell wall loosening in roots. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometers (MALDI-TOFMS)-based analysis clearly revealed that pectin-polysaccharides in roots were degraded; they are one of the main matrix-polysaccharide-connecting and load-bearing polymers in cell walls. Rapid root elongation led to structural changes in root cell walls: reduction of cell wall thickness and a bias on the orientation of cellulose microfibrils. Additionally, the asymmetrical distribution of tensional strength resulted from the OH radical-induced cell wall loosening enhanced endocytosis. These findings emphasize that OH radical-induced cell wall loosening is important for mechanical regulation of the cell wall and provide new insights into the cellular responses of plants exposed to reactive metal nanoparticles.
This study was aimed to evaluate the association between urinary bisphenol A (BPA) levels and risk of obesity in Korean adults. We analyzed data from the Korean National Environmental Health Survey ...(KoNEHS) Cycle 2 (2012-2014) and Cycle 3 (2015-2017). A total of 10,021 participants aged ≥ 19 years were included. Urine dilution was corrected by the covariate-adjusted standardization (CAS) method. We performed meta-analysis, logistic regression analysis by matching all covariates with a 1:1 propensity score, and a 4-knot restricted cubic spline plot model to calculate the odds ratios (ORs) for obesity according to natural log-transformed BPA levels. Mean urinary BPA concentration was 1.12 µg/L in KoNEHS Cycle 2 and 1.32 µg/L in Cycle 3. BPA levels were significantly higher among obese adults than among non-obese adults in both KoNEHS Cycles 2 and 3. In pooled data of KoNEHS Cycles 2 and 3, BPA showed significant positive associations with ORs for obesity in both sexes, which were more prominent in females (linear) than in males (non-linear). These associations were confirmed in spline analyses. CAS-applied BPA concentrations were positively associated with obesity in nationwide representative samples of Korean adults. Further studies are warranted to confirm and elucidate the underlying mechanism.
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•Ionic and neutral PFASs were analyzed simultaneously in 9 environmental matrices.•Industrial complex and WWTP were major emission sources•The effects of emission source and their ...spatial distribution were confirmed.•Long chain PFCAs and PFOS were dominant in dust, soil, sediment and sludge.•PFBS and neutral PFASs were dominant in air, whereas PFCAs were dominant in biota.
This study investigated perfluoroalkyl substances (PFASs) in multimedia environments to confirm the effects of emission sources of PFASs and to elucidate their spatial distribution. The highest PFAS levels were detected from the samples of air (272.30 pg/m3) and surface water (36.54 ng/L) in an industrial complex area, meanwhile high PFAS levels were found from the samples of soil (8.80 ng/g) and sediment (84.98 ng/g) in urban areas and near wastewater treatment plants (WWTPs). Perfluorobutane sulfonate (PFBS) was primarily detected in water, influent and effluent, whereas long chain perfluorocarboxylic acids (PFCAs) and perfluorooctane sulfonate (PFOS) were dominant in dust, soil, sediment and sludge. While PFBS and neutral PFASs were dominant in air, PFCAs were primarily detected in plant and fish. The specific distribution patterns of PFASs in each matrix showed the influences of surrounding environments and different physicochemical characteristics of each congener. These findings suggest that the industrial complex and WWTP might be major emission sources to air and aquatic environments, respectively. This is the first study in which 6 neutral and 13 ionic PFASs were investigated simultaneously for nine different matrices in multimedia environments, and also it would be a good model study for future assessment of PFASs.
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