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For the direct alkaline oxidation of rice husk lignin, we developed a copper foam-based heterogeneous catalyst that offers advantages in its recovery after the reaction mixture. The depolymerized products were utilized for muconate production by an engineered Pseudomonas sp. NGC7-based strain. A hydroxide nanorod-modified copper foam was prepared by the surface oxidation of copper foam, followed by alkaline oxidation of rice husk lignin over the catalyst. The catalyst was easily separated from the cellulosic residues in the reaction mixture, and the residues were then recovered by filtration. The resulting lignin stream was composed of a variety of aromatic monomers containing p-hydroxyphenyl, guaiacyl, and syringyl compounds. The catabolic activity of Pseudomonas sp. NGC7 was demonstrated to be more suitable for muconate production from a mixture comprising 4-hydroxybenzoate (a typical p-hydroxyphenyl compound), vanillate (a guaiacyl compound), and syringate (a syringyl compound), owing to its natural ability to grow on syringate. Thus, it was applied to produce muconate from a rice husk lignin stream prepared through hydroxide nanorod-modified copper foam-catalyzed alkaline oxidation by conferring the genes responsible for converting the acetophenone derivatives to their corresponding aromatic acids and protocatechuate decarboxylase to an NGC7-based strain deficient in protocatechuate 3,4-dioxygenase and muconate cycloisomerase. As a result, the engineered NGC7-based muconate-producing strain produced muconate selectively from the rice husk lignin stream at 93.7 mol% yield., (Copyright © 2024 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

RNA interference (RNAi)-based biopesticides offer an attractive avenue for pest control. Previous studies revealed high RNAi sensitivity in Holotrichia parallela larvae, showcasing its potential for grub control. In this study, we aimed to develop an environmentally friendly RNAi method for H. parallela larvae. The double-stranded RNA (dsRNA) of the V-ATPase-a gene ( HpVAA ) was loaded onto layered double hydroxide (LDH). The dsRNA/LDH nanocomplex exhibited increased environmental stability, and we investigated the absorption rate and permeability of dsRNA-nanoparticle complexes and explored the RNAi controlling effect. Silencing the HpVAA gene was found to darken the epidermis of H. parallela larvae, with growth cessation or death or mortality, disrupting the epidermis and midgut structure. Quantitative reverse transcription-polymerase chain reaction and confocal microscopy confirmed the effective absorption of the dsRNA/LDH nanocomplex by peanut plants, with distribution in roots, stems, and leaves. Nanomaterial-mediated RNAi silenced the target genes, leading to the death of pests. Therefore, these findings indicate the successful application of the nanomaterial-mediated RNAi system for underground pests, thus establishing a theoretical foundation for developing a green, safe, and efficient pest control strategy.

The development of cost-effective and eco-friendly fertilizers is crucial for enhancing iron (Fe) uptake in crops and can help alleviate dietary Fe deficiencies, especially in populations with limited access to meat. This study focused on the application of MgFe-layered double hydroxide nanoparticles (MgFe-LDHs) as a potential solution. We successfully synthesized and characterized MgFe-LDHs and observed that 1-10 mg/L MgFe-LDHs improved cucumber seed germination and water uptake. Notably, the application of 10 mg/L MgFe-LDHs to roots significantly increased the seedling emergence rate and growth under low-temperature stress. The application of 10 mg/L MgFe-LDHs during sowing increased the root length, lateral root number, root fresh weight, aboveground fresh weight, and hypocotyl length under low-temperature stress. A comprehensive analysis integrating plant physiology, nutrition, and transcriptomics suggested that MgFe-LDHs improve cold tolerance by upregulating SA to stimulate CsFAD3 expression, elevating GA 3 levels for enhanced nitrogen metabolism and protein synthesis, and reducing levels of ABA and JA to support seedling emergence rate and growth, along with increasing the expression and activity of peroxidase genes. SEM and FTIR further confirmed the adsorption of MgFe-LDHs onto the root hairs in the mature zone of the root apex. Remarkably, MgFe-LDHs application led to a 46% increase (p < 0.05) in the Fe content within cucumber seedlings, a phenomenon not observed with comparable iron salt solutions, suggesting that the nanocrystalline nature of MgFe-LDHs enhances their absorption efficiency in plants. Additionally, MgFe-LDHs significantly increased the nitrogen (N) content of the seedlings by 12% (p < 0.05), promoting nitrogen fixation in the cucumber seedlings. These results pave the way for the development and use of LDH-based Fe fertilizers., (© 2024. The Author(s).)

A biohybrid therapeutic system, consisting of responsive materials and living microorganisms with inter-cooperative effects, is designed and investigated for tumor treatment. In this biohybrid system, S 2 O 3 2- -intercalated CoFe layered double hydroxides (LDH) are integrated at the surface of Baker's yeasts. Under the tumor microenvironment, functional interactions between yeast and LDH are effectively triggered, resulting in S 2 O 3 2- release, H 2 S production, and in-situ generation of highly catalytic agents. Meanwhile, the degradation of LDH in the tumor microenvironment induces the exposure of the surface antigen of yeast, leading to effective immune activation at the tumor site. By virtue of the inter-cooperative phenomena, this biohybrid system exhibits significant efficacy in tumor ablation and strong inhibition of recurrence. This study has potentially offered an alternative concept by utilizing the metabolism of living microorganisms and materials in exploring effective tumor therapeutics., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Super dosing copper (Cu) has long been used as an alternative to antibiotic growth-promoters in broiler chickens' diet to improve gut health. This study was designed to compare nutritional and growth-promoting levels of Cu hydroxychloride (CH) with CuSO 4 on gut health bio-markers and liver mineral profile of broiler chickens. Ross 308 chicks (n = 864) were randomly assigned to eight treatments, as basal diet containing no supplemental Cu; the basal diet with 15 or 200 mg/kg Cu as CuSO 4 ; or 15, 50, 100, 150 or 200 mg/kg Cu from CH. The highest liver Cu content was observed in birds fed the diets with 200 mg/kg CuSO 4 (P < 0.01). Serum FITC-d concentration as the leaky gut marker, and liver malondialdehyde concentration were not affected. Copper level or source had no effect on cecal short chain fatty acid and the mRNA expression of five jejunal genes involved in gut integrity. Negative linear responses of Cu were observed on Lactobacillus (P = 0.032), Bacteroides (P = 0.033), and Enterobacteriaceae (P = 0.028) counts. The jejunal villus height increased in birds fed CH at 200 and 100 mg/kg (P < 0.05). Increasing Cu levels, linearly and quadratically (P < 0.001), increased Cu excretion., (© 2022. The Author(s).)

Leukemia inhibitory factor (LIF), an indispensable bioactive protein that sustains self-renewal and pluripotency in stem cells, is vital for mouse embryonic stem cell (mESC) culture. Extensive research is conducted on reliable alternatives for LIF as its clinical application in stable culture and large-scale expansion of ESCs is limited by its instability and high cost. However, few studies have sought to replace LIF with nanoparticles to provide a xeno-free culture condition. MgAl-LDH (layered double hydroxide) nanoparticles can partially replace LIF in maintaining pluripotency of mESCs; however, the requirement and tolerance for aluminum ions in mice are far lesser than those of iron ions. Hence, MgFe-LDH nanoparticles are selected for this study. MgFe-LDH is superior to MgAl-LDH in maintaining self-renewal and pluripotency of mESCs, in the absence of LIF and mouse embryonic fibroblast. Furthermore, combined transcriptomic and proteomic analysis confirms that MgFe-LDH can activate the LIF receptor (LIFR)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B(AKT), LIFR/JAK/janus kinase (JAK)/signal transducer and activator of transcription 3(STAT3), and phospho-signal transducer and activator of transcription 3(p-STAT3)/ten-eleven translocation (TET) signaling pathways, while the extra Fe 2+ provided by MgFe-LDH would also enhance TET1/2 abundance thus affecting the TET1/2 regulated pluripotency related marker expression and TET1/2 meditated DNA demethylation. These results suggest that MgFe-LDH nanoparticles can thus be used as an affordable and efficient replacement for LIF in mESC cultivation., Competing Interests: The authors declare no conflict of interest., (© 2021 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

The major obstacle to developing nanozymes which are considered as promising alternatives to natural enzymes is their moderate performance, including poor affinity for substrates, low catalytic activity, and severe pH-dependence. To address these issues, herein, we synthesize ultrathin layered double hydroxide (LDH) nanosheets with a thickness of 1.4 nm and an average lateral size of 23 nm using a fast-precipitation method. Through the rational design of their compositions, it is found that NiMn LDHs exhibit the optimum peroxidase mimicking performance with excellent substrate affinity, high catalytic activity (a limit of detection (LOD) of 0.04 μM H 2 O 2 ) and robustness in a wide pH range (from 2.6 to 9.0), which is superior to that of natural horseradish peroxidase (HRP). The main active centers are identified as Mn sites because of their strong Lewis acidity and low redox potential. Furthermore, a series of disposable paper bioassays based on NiMn LDH nanozymes are designed and used for the highly sensitive detection of H 2 O 2 and ascorbic acid (AA).

Nickel-iron composites are efficient in catalyzing oxygen evolution. Here, we develop a microorganism corrosion approach to construct nickel-iron hydroxides. The anaerobic sulfate-reducing bacteria, using sulfate as the electron acceptor, play a significant role in the formation of iron sulfide decorated nickel-iron hydroxides, which exhibit excellent electrocatalytic performance for oxygen evolution. Experimental and theoretical investigations suggest that the synergistic effect between oxyhydroxides and sulfide species accounts for the high activity. This microorganism corrosion strategy not only provides efficient candidate electrocatalysts but also bridges traditional corrosion engineering and emerging electrochemical energy technologies.

The overdeveloped lysosomes in cancer cells are gaining increasing attention toward more precise and effective organelle-targeted cancer therapy. It is suggested that rod/plate-like nanomaterials with an appropriate size exhibited a greater quantity and longer-term lysosomal enrichment, as the shape plays a notable role in the nanomaterial transmembrane process and subcellular behaviors. Herein, a biodegradable platform based on layered double hydroxide-copper sulfide nanocomposites (LDH-CuS NCs) is successfully prepared via in situ growth of CuS nanodots on LDH nanoplates. The as-prepared LDH-CuS NCs exhibited not only high photothermal conversion and near-infrared (NIR)-induced chemodynamic and photodynamic therapeutic efficacies, but also could achieve real-time in vivo photoacoustic imaging (PAI) of the entire tumor. LDH-CuS NCs accumulated in lysosomes would then generate extensive subcellular reactive oxygen species (ROS) in situ, leading to lysosomal membrane permeabilization (LMP) pathway-associated cell death both in vitro and in vivo.

Designing the catalytic interface that preferentially attracts reactants is highly desirable for amplifying chemiluminescence (CL) emission. Herein, to boost the generation of reactive oxygen species (ROS) from dissolved O 2 molecule, flower-like cobalt hydroxide (f-Co(OH) 2 ) based catalytic interface with hierarchical and porous architecture were in situ created in the coexistence of BSA and Co 2+ . Benefiting from the oxidase-like catalysis capability and the unique microstructure of f-Co(OH) 2 , ROS was efficiently produced. Meanwhile, the capping ligands of BSA endowed the interface with the capability of enriching functionality through the interaction between BSA and luminol. 100-fold CL enhancement was achieved using the as-prepared catalytic interface compared with the classical luminol-Co 2+ or luminol-BSA system. Moreover, the proposed catalytic amplification mechanism could be extended to the different proteins such as lysozyme, protamine, thrombin, papain. Based on the quenching effect on CL, a sensitive sensing platform was constructed for the determination of ascorbic acid with satisfied results. Our finding provided a novel "all-in-one" route to design the catalytic interface for amplifying CL emission.

In this work, hexacyanoferrate intercalated Ni/Al LDH (Ni/Al-Fe(CN) 6 LDH) nanozyme was synthesized by one-pot co-precipitation method and used for determination of chromium in water samples by employing its peroxidase mimicking activity. The synthesized nanozyme can effectively catalyze the oxidation of fluorometric peroxidase substrate terephthalic acid by H 2 O 2 to produce a highly fluorescent product. It was found that Cr(VI) promotes the peroxidase-like activity of Ni/Al-Fe(CN) 6 LDH and this effect was intensified by increasing the Cr(VI) concentration. Several variables affecting the fluorescence intensity including the concentration of nanoparticles and reagents as well as reaction time were investigated and optimized. Under the optimal conditions, good linearity was observed in the range of 0.067-10 μM Cr(VI), and limit of detection and quantification were found to be 0.039 and 0.131 μM, respectively. Furthermore, the developed method showed good applicability for the determination of total Cr based on the oxidation of Cr (III) to Cr (VI). The applicability of the proposed method was demonstrated by analyzing various environmental water samples. The presented nanozyme displayed superior benefits in terms of reusability, repeatability, cost and environment-friendly features. The present work aims to expand LDHs based enzyme mimics to optical sensor fields., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The fabricating of metal oxide thin films onto conducting surfaces continues to grow and their potential applications as surfaces for biosensor applications is of paramount importance. The correct orientation of glucose oxidase redox enzymes yields very important biointerfaces capable of selectively detecting d-glucose as a measure of blood sugar for healthy and diabetic sick patients. The electrodeposition of redox enzymes, such as glucose oxidase enzymes, onto gold electrode surfaces pre-modified with nickel oxide was investigated in this work. The surface characterization confirmed the chemical nature, morphology and thin film composition of the modification of bare and modified gold electrodes. The electrodeposition of GOx enzyme onto nickel oxide/hydroxide thin film resulted in a surface with excellent bioelectrocatalytic properties towards the detection of d-glucose. The nickel within the nickel oxide/hydroxide thin film had a Ni(II) oxidation state. A well-defined redox peak of GOx enzyme co-factor (FAD/FADH 2 ) was observed confirming the oriented immobilization onto NiO/Ni(OH) 2 conducting surfaces. The amount of GOx enzyme deposited was determined by integrating the charge (Q = 0.368 μF) under the reduction peak and the surface coverage was found to be 1.43 × 10 -10 mol. cm -2 . A linear plot of electrocatalytic reduction currents against d-glucose concentrations was obtained up to 30.0 mM with a linear correlation coefficient (R 2 ) of 0.99. The limit of detection (LoD) using S/N = 3 was calculated to be 1.54 ± 0.03 mM. The sensitivity of the biosensors was 1.95 ± 0.13 μA.mM.cm -2 . The selectivity towards only d-glucose and not ascorbic acid and uric acid was evaluated and the Au-NiO/Ni(OH) 2 -GOx could not detect 1.0 mM of ascorbic acid and uric acid., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Chitin is the second most abundant and renewable polysaccharide, next to cellulose. Hydrolysis of abundant and highly crystalline α-chitin, pretreated with KOH and KOH-urea aqueous solutions, by a single modular endo-chitinase from Enterobacter cloacae subsp. cloacae (EcChi1) was investigated. The hydrolysis of untreated α-chitin and colloidal chitin by EcChi1 produced N-acetylglucosamine and N, N'-diacetylchitobiose, whereas, hydrolysis of treated substrates generated N, N', N''-triacetylchitotriose, in addition to N-acetylglucosamine and N, N'-diacetylchitobiose. The total amount of chitooligosaccharides (COS) generated by EcChi1 from pretreated substrates was 10 to 25-fold higher compared to untreated α-chitin at 24 h (depending on the solvent type and state of substrate). EcChi1 released higher amount of DP1 and DP2 products on treated α-chitin, with a fold change of 45 and 18, respectively. Treatment of α-chitin with KOH/KOH-urea is, therefore, a promising approach for an efficient conversion of rich source of chitin to soluble COS by chitinases like EcChi1., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The hydrotalcite-supported palladium (Pd) catalyst is prepared with a green and environmentally friendly route, introducing the extract of withered leaves as a dispersant and reducing agent (Pd/LDHs-B). Compared with the as-prepared catalyst (Pd/LDHs-P with the average diameter of 4.3 nm) using a chemical synthesis method with polyvinylpyrrolidone as a dispersant and ascorbic acid (Vc) as a reductant, the results indicate that the size of Pd nanoparticles in Pd/LDHs-B is smaller (ca. 3.6 nm). The Pd-LHDs-B (0.5 mmol‰) exhibits higher activity (98.66%) than Pd/LDHs-P (98.19%) in the Suzuki reaction of 4-bromotoluene and phenylboronic acid at 60°C for 30 min. Also, the reusability of Pd/LDHs-B is confirmed by recycling tests without a significant decrease in activity.

A new type of artificial giant liposome incorporating ion transport channels and using nanoparticles of metal organic frameworks was demonstrated. The micropores of Prussian blue nanoparticles served as ion transport channels between the outer and inner phases of liposomes.

Two promiscuous Bacillus licheniformis glycosyltransferases, YdhE and YojK, exhibited prominent stereospecific but nonregiospecific glycosylation activity of 20 different classes of 59 structurally different natural and non-natural products. Both enzymes transferred various sugars at three nucleophilic groups (OH, NH 2 , SH) of diverse compounds to produce O -, N -, and S -glycosides. The enzymes also displayed a catalytic reversibility potential for a one-pot transglycosylation, thus bestowing a cost-effective application in biosynthesis of glycodiversified natural products in drug discovery.

Chemical isotope labeling (CIL) liquid chromatography mass spectrometry (LC-MS) is a powerful technique for in-depth metabolome analysis with high quantification accuracy. Unlike conventional LC-MS, it analyzes chemical-group-based submetabolomes and uses the combined results to represent the whole metabolome. Due to analysis time and cost constraint, not all submetabolomes can be profiled and thus knowledge of chemical group classification is important in guiding submetabolome selection. Herein we report a study of determining the distribution of functional groups of compounds in a database and then examine how well we can experimentally analyze the major chemical groups in two representative samples (i.e., human plasma and yeast). We developed a computer algorithm to classify chemical structures according to their functional groups. After removing lipids which are targeted molecules in lipidomic analysis, inorganic species and other molecules that are unique to drug, food, plant, and environmental origins, five groups (i.e., amine, phenol, hydroxyl, carboxyl, and carbonyl) are found to be the dominant classes. In the databases of MCID (2683 filtered metabolites), HMDB (5506), KEGG (11598), YMDB (1107), and ECMDB (1462), 94.7%, 85.7%, 86.4%, 85.7%, and 95.8% of the filtered metabolites belong to one or more of the five groups, respectively. These groups can be analyzed in four-channel CIL LC-MS where hydroxyls (H), amines and phenols (A), carboxyls (C), and carbonyls or ketones/aldehydes (K) are separately profiled as individual channels using dansyl and DmPA labeling reagents. A total of 7431 peak pairs were detected with 6109 unique-mass pairs from plasma, while 5629 pairs with 4955 unique-mass pairs were detected in yeast. Compared to group distributions of database compounds, hydroxyl-containing metabolites were severely underdetected, which might indicate that the current method is less than optimal for analyzing this group of metabolites. As a result, the overall experimental coverage is likely significantly lower than the database-derived coverage. In short, this study has shown that high metabolome coverage is theoretically attainable by analyzing only the H, A, C, and K submetabolomes and the group classification information should be helpful in guiding future analytical method development and choices of submetabolomes to be analyzed.

Nanobiocatalysis is the combination of the unique properties of nano-sized materials and the efficiency and sophistication of catalytic properties of enzymes. In this work, Cu(OH) 2 nanocages with an mean size of 170 nm were synthesized and used as a support for the covalent conjugation with fungal ligninolytic enzymes; versatile peroxidase and laccase. Both enzymes have the ability to degrade a wide range of pollutants. The nanocages were characterized, the orthorhombic arrangement of the nanocages was confirmed and TEM images showed that the nanocages are composed of nano-ribbons stacked around the particles. Interestingly, bioconjugated laccase-nanocages exhibited up to 18-times higher catalytic rate that these found for free enzyme, while activity of versatile peroxidase-nanocages was considerably reduced. The total turnover number for free laccase and laccase-nanocages are similar, suggesting that the activity increase is not due to the supply of Cu ions to a possible Cu-depleted active site of laccase. This enhancement of laccase activity when immobilized enzyme onto Cu(OH) 2 nanocages could be important for the actual and potential industrial uses of laccases., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Copper-based fungicides have been used for a long time in viticulture and have accumulated in many vineyard soils. In this study, incrementing Cu(OH) 2 -based fungicide application from 0.05 to 5 g Cu kg -1 on two agricultural soils (an acidic sandy loam (L, pH 4.95) and an alkaline silt loam (D, pH 7.45)) resulted in 5 times more mobile Cu in the acidic soil. The most sensitive parameters of alfalfa (Medicago sativa) growing in these soils were the root nodule number, decreasing to 34% and 15% of the control at 0.1 g Cu kg -1 in soil L and at 1.5 g Cu kg -1 in soil D, respectively, as well as the nodule biomass, decreasing to 25% and 27% at 0.5 g Cu kg -1 in soil L and at 1.5 g Cu kg -1 in soil D, respectively. However, the enzymatic N 2 -fixation was not directly affected by Cu in spite of the presence of Cu in the meristem and the zone of effective N 2 -fixation, as illustrated by chemical imaging. The strongly different responses observed in the two tested soils reflect the higher buffering capacity of the alkaline silt loam and showed that Cu mitigation and remediation strategies should especially target vineyards with acidic, sandy soils.

Photothermal therapy had great potential in being a new approach of tumour ablation due to their high selectivity and low side effect. However, the shallow penetration depth of near-infrared (NIR) irradiation resulted in the limited curative effect. Herein, a novel nanomedicine was developed based on the indocyanine green-loaded vanadium oxide nanocomposites (VO 2 -ICG) for pH-activated NIR luminescence imaging-guided enhanced photothermal tumour ablation. In acidic tumour microenvironment, the VO 2 NPs were decomposed and released VO 2+ , which could not only inhibit the function of 60 kDa heat shock protein (HSP60), but also generate hydroxyl radical (OH) by catalysing intratumoral H 2 O 2 . Furthermore, the ICG was also released in the decomposition process of VO 2 NPs, allowing the pH-activated NIR luminescence imaging and photothermal therapy. The inhibition of HSP60 down-regulated the heat tolerance of cells and the generation of OH up-regulated the intracellular oxidative stress, which enhanced the photothermal therapeutic efficiency. Our work demonstrated a promised method to enhance photothermal therapeutic effect, highlighting the importance of HSP inhibition and OH generation in promoting cell apoptosis under mild hyperthermia., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Identification of onychomycosis is mainly based on clinical diagnosis with auxiliary diagnostic methods such as potassium hydroxide (KOH) microscopy, periodic acid-Schiff staining or fungal culture. However, each method is limited by its sensitivity and specificity., Aim: To develop a new test method using the common fungal end product, ergosterol, and investigate if it can be used as a new diagnostic tool., Methods: We collected consecutive data from 20 participants with nail problems. Following clinical diagnosis, samples were taken for KOH microscopy and for mass spectrometry (MS) to check for the presence of ergosterol., Results: Of the 20 cases collected, 7 were positive for fungal infection by MS. Four of these were already suspected to have onychomycosis, whereas one of the remaining three subjects was presumed to have dry nail and the other two to have onycholysis. The MS test seemed to be better at detecting combinations of nail conditions. Conversely, of the five patients clinically diagnosed as having onychomycosis, four had a positive MS result, whereas the fifth had negative results on both KOH and MS. Two other participants had a positive KOH test and were also found to have positive MS results., Conclusion: Detection of the presence of ergosterol by MS seems to be a useful tool for confirming onychomycosis. However, further studies are needed to verify the sensitivity and specificity of this MS method., (© 2019 British Association of Dermatologists.)

Nanozymes' activities could be regulated by a simple and effective pH change in an in situ manner. In this work, for the first time, the peroxidase-like activity of Ni/Co layered double hydroxides (LDHs) was regulated via the alkaline-promoted reaction of fluorogenic substrate homovanillic acid and H 2 O 2 , and a promising tool for pH sensing was developed over the pH range of 8.3-9.6. As peroxidase nanozyme model, Ni/Co LDHs showed ease of preparation, low-cost, and water-solubility, which played an important role in this luminescence system. Based on the pH-dependent regulation of the Ni/Co LDHs activity, we constructed the bioassay platform for the determination urea, urease, penicillin G, and penicillinase with a wide linear range of 17-1000 µM, 3.3-270 mU mL -1 , 3.3-1300 µM and 3.3-100 mU mL -1 , respectively. This study not only demonstrated the alkaline-promoted modulation the nanozymes' activities, but also established a facile approach to develop novel bioassays., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A novel cysteine intercalated copper aluminum layered double hydroxide (CuAl-Cys-LDH) was synthesized and applied as heterogeneous catalyst for activating hydrogen peroxide (H 2 O 2 ) to degrade rhodamine B (RhB) and 4-Nitrophenol (4-NP). The effects of initial pH, CuAl-Cys-LDH dosage, and H 2 O 2 concentration on RhB and 4-NP removal were comprehensively investigated. The results indicated the intercalation of cysteine into the interlayer of LDH greatly enhanced its catalytic activity and stability. With 0.2 g/L CuAl-LDH and 50 mM H 2 O 2 , 93.7% of RhB and 80.2% of 4-NP could be removed in the CuAl-Cys-LDH activated H 2 O 2 system. While the CuAl- LDH activated H 2 O 2 system could only degrade 51.2% of RhB and 46.8% of 4-NP under the identical experimental conditions. Significantly, the CuAl-Cys-LDH catalyzed H 2 O 2 system exhibited high degradation efficiency within a wide pH range from 4.0 to 10.0. Based on the electron paramagnetic resonance (EPR) tests and radical quenching experiments, it was inferred that •OH radical was the dominant species responsible for organic contaminants degradation. Mechanism study revealed that the intercalated cysteine in the interlayer of LDH strongly accelerated the rate-determining conversion of Cu(II) to Cu(I) by oxidation itself to cystine, thus enhanced the catalytic efficiency for H 2 O 2 activation to produce •OH radicals. The findings of this work indicated that CuAl-Cys-LDH is a conveniently prepared and highly efficient and stable catalyst for the degradation of organic contaminants in environmental remediation., (Copyright © 2019 Elsevier Inc. All rights reserved.)

A highly stable nanocomposite of antioxidant activity was developed by immobilization of a superoxide dismutase-mimicking metal complex on copolymer-functionalized nanoclay. The layered double hydroxide (LDH) nanoclays were synthesized and surface modification was performed by adsorbing poly(vinylpyridine-b-methacrylic acid) (PVPMAA). The effect of the adsorption on the charging and aggregation properties was investigated and the copolymer dose was optimized to obtain stable LDH dispersions. The LDH-PVPMAA hybrid particles showed high resistance against salt-induced destabilization in aqueous dispersions. Copper(II)-histamine (Cu(Hsm) 2 ) complexes were immobilized via the formation of dative bonds between the metal ions and the nitrogen atoms of the functional groups of the copolymer adsorbed on the particles. Changes in the coordination geometry of the complex upon immobilization led to higher superoxide radical anion scavenging activity than the one determined for the non-immobilized complex. Comparison of superoxide dismutase (SOD)-like activity of the obtained hybrid LDH-PVPMAA-Cu(Hsm) 2 with the nanoclay-immobilized SOD enzyme revealed that the developed composite maintained its activity over several days and was able to function at elevated temperature, while the immobilized native enzyme lost its activity under these experimental conditions. The developed nanocomposite is a promising antioxidant candidate in applications, where high electrolyte concentration and elevated temperature are applied., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In situ synthesis of layered double hydroxides (LDHs) was proved to be an effective way to extract short chain fatty acids (SCFAs) from anaerobic fermentation liquid (AFL) as carbon source for biodenitrification, but the SCFAs content in SCFAs-LDH was unsatisfactory because of the existence of much carbonate in AFL. Pretreatment of AFL with calcium addition was investigated to remove carbonate and improve SCFAs extraction via LDHs synthesis. Results of batch tests showed that, the carbonate removal efficiency was as high as 76.6% when the calcium addition was 0.06 mol/L at pH 12. When using the optimal SCFAs/Al 3+ ratio of 3.0, the total SCFAs content in SCFAs-LDH with pretreatment was improved to 46.5 mg COD/g LDH, which was 4.5 times of the control (10.4 mg COD/g LDH). These results suggest that adding calcium to AFL was an effective way to eliminate the negative effect of carbonates on SCFAs-LDH synthesis., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The development of new multifunctional materials integrating catalytically active and selective biomolecules, such as enzymes, as well as easily removable and robust inorganic supports that allow their use and reuse, is a subject of ongoing attention. In this work, the nitroreductase NfrA2/YncD (NR) from Bacillus megaterium Mes11 strain was successfully immobilized by adsorption and coprecipitation on layered double hydroxide (LDH) materials with different compositions (MgAl-LDH and ZnAl-LDH), particle sizes and morphologies, and using different enzyme/LDH mass ratios (Q). The materials were characterized and the immobilization and catalytic performance of the biohybrids were studied and optimized. The nitroreductase-immobilized on the nanosized MgAl-LDH displayed the best catalytic performance with 42-46% of catalytic retention and>80% of immobilization yield at saturation values of enzyme loading Cs ≈ 0.6 g NR/g LDH (Q = 0.8). The adsorption process displayed high enzyme-LDH affinity interactions yielding to a stable biohybrid material. The increase in the amount of enzyme loading favoured the catalytic performance of the biohybrid due to the better preservation of the native conformation. The biohybrid was reused several times with partial activity retention after 4 cycles. In addition, the biohybrid was successfully dried maintaining the catalytic activity for several weeks when it was stored in its dry form. Finally, thin films of NR@LDH biohybrid deposited on glassy carbon electrodes were evaluated as a modified electrode applied for nitro-compound detection. The results show that these biohybrids can be used in biotechnology applications to efficiently detect compounds such as dinitrotoluene. The search for new non-hazardous chemical designs preventing or reducing the use of aggressive chemical processes for human being and the environment is the common philosophy within sustainable chemistry., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Traditional strategies for the functionalization of materials displaying hydroxyl groups either require active esterification reagents or involve the nucleophilic attack of the hydroxyl group toward electrophilic groups. The former tends to hydrolyze in aqueous solutions while the latter occurs under harsh conditions. Herein, the authors reported a new method for the functionalization of hydroxyl groups on the surface via catalytic oxa-Michael addition with vinyl sulfones. Using hydroxyl group terminated self-assembled monolayers as a model surface, a series of organocatalysts were screened and triphenylphosphine stood out for the best catalytic activity. The catalytic reaction on the surface was characterized by x-ray photoelectron spectroscopy. The information of reaction kinetics was obtained using static water contact angle measurements. Once conjugated with ligands onto the functionalized surfaces, the multivalence binding of proteins was investigated by quartz crystal microbalance experiments. By varying the reaction conditions, e.g., catalyst types and reaction times, ligands can be anchored with a controllable density, which would be helpful to establish the relationships between ligand density and bioactivity.

Metallothioneins (MTs) are involved in cellular homeostasis of essential metal ions and detoxification of nonessential metal ions. We report here the identification of four MT genes, CtMT1, CtMT2, CtMT3 and CtMT4, encoding CtMT1, CtMT2, CtMT3 and CtMT4 proteins, respectively, from the industrial guar crop. The primary structures of last three proteins were similar to those of respective MT proteins of other plants but the CtMT1 protein primary structure was different from the other plant MT1 proteins in having an additional C-X-C motif. The four MT genes showed tissue specific expression patterns suggesting their specific roles in different tissues. High expression of CtMT1 gene was observed in roots and nodules whereas CtMT2 and CtMT3 genes showed high expression in leaves. The expression of CtMT4 gene was high in seeds. The qRT-PCR studies revealed upregulation in expression of CtMT1 gene under drought stress. Recombinant CtMT1 protein was produced in E. coli Rosetta cells and purified by metal affinity chromatography. The purified protein showed antioxidant property and the order of its metal ion binding affinities was Cu 2+  > Zn 2+  > Fe 2+  > Cd 2+ . This information about CtMT1 protein is expected to be useful in understanding its role in drought tolerance and other physiological processes of guar., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Ladderane lipids are unique to anaerobic ammonium-oxidizing (anammox) bacteria and are enriched in the membrane of the anammoxosome, an organelle thought to compartmentalize the anammox process, which involves the toxic intermediate hydrazine (N 2 H 4 ). Due to the slow growth rate of anammox bacteria and difficulty of isolating pure ladderane lipids, experimental evidence of the biological function of ladderanes is lacking. We have synthesized two natural and one unnatural ladderane phosphatidylcholine lipids and compared their thermotropic properties in self-assembled bilayers to distinguish between [3]- and [5]-ladderane function. We developed a hydrazine transmembrane diffusion assay using a water-soluble derivative of a hydrazine sensor and determined that ladderane membranes are as permeable to hydrazine as straight-chain lipid bilayers. However, pH equilibration across ladderane membranes occurs 5-10 times more slowly than across straight-chain lipid membranes. Langmuir monolayer analysis and the rates of fluorescence recovery after photobleaching suggest that dense ladderane packing may preclude formation of proton/hydroxide-conducting water wires. These data support the hypothesis that ladderanes prevent the breakdown of the proton motive force rather than blocking hydrazine transmembrane diffusion in anammox bacteria., Competing Interests: The authors declare no conflict of interest.

Polysiloxanes have shown exquisite properties for fabrication of microstructures for various biomedical and biotechnological applications. Nevertheless, their biocompatibility in terms of cell adhesion and survival ability is controversial. A simple polysiloxane modifying procedure that reproducibly enhances cell adhesion was proposed. Sonication of the hybrid organic-inorganic polymer of polysiloxane type, Ormocomp, in potassium hydroxide (KOH)/ethanol solution enhanced adhesion and subsequent survival of a panel of four cell lines. Characterization of surface properties of untreated and KOH-treated Ormocomp coatings has revealed considerable negative charge of Ormocomp substrates based on measurements of zeta potentials. KOH treatment did not modify surface morphology as visualized by scanning electron microscopy, but it resulted in alteration in both chemical composition according to SIMS analysis and hydrophilicity evaluated by static water contact angles. The results suggest that the failure of the adherent cells to survive on Ormocomp coatings is related to cell adhesion. The negative surface charge of Ormocomp substrates may be one of the influencing factors; however, the modification of surface chemistry mediated by KOH and the resulting increase in hydrophilicity accompanied by modification of protein adsorption are more likely responsible for enhanced cell adhesion and survival on Ormocomp coatings. KOH treatment thus may serve as a simple, cost-effective procedure modifying polysiloxane-type polymers that leads to reproducible enhancement of cell adhesion.

This review highlights the current research on the interactions between biological cells and Layered Double Hydroxides (LDH). The as-prepared biohybrid materials appear extremely attractive in diverse fields of application relating to health care, environment and energy production. We describe how thanks to the main features of biological cells and LDH layers, various strategies of assemblies can be carried out for constructing smart biofunctional materials. The interactions between the two components are described with a peculiar attention to the adsorption, biocompatibilization, LDH layer internalization, antifouling and antimicrobial properties. The most significant achievements including authors' results, involving biological cells and LDH assemblies in waste water treatment, bioremediation and bioenergy generation are specifically addressed., (© 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

To understand salt stress, the full impact of salinity on plant cell physiology has to be resolved. Electrical measurements suggest that salinity inhibits the proton pump and opens putative H + /OH - channels all over the cell surface of salt sensitive Chara australis (Beilby and Al Khazaaly 2009; Al Khazaaly and Beilby 2012). The channels open transiently at first, causing a characteristic noise in membrane potential difference (PD), and after longer exposure remain open with a typical current-voltage (I/V) profile, both abolished by the addition of 1 mM ZnCl 2 , the main known blocker of animal H + channels. The cells were imaged with confocal microscopy, using fluorescein isothiocyanate (FITC) coupled to dextran 70 to illuminate the pH changes outside the cell wall in artificial fresh water (AFW) and in saline medium. In the early saline exposure, we observed alkaline patches (bright fluorescent spots) appearing transiently in random spatial distribution. After longer exposure, some of the spots became fixed in space. Saline also abolished or diminished the pH banding pattern observed in the untreated control cells. ZnCl 2 suppressed the alkaline spot formation in saline and the pH banding pattern in AFW. The osmotic component of the saline stress did not produce transient bright spots or affect banding. The displacement of H + from the cell wall charges, the H + /OH - channel conductance/density, and self-organization are discussed. No homologies to animal H + channels were found. Salinity activation of the H + /OH - channels might contribute to saline response in roots of land plants and leaves of aquatic angiosperms.

In this study, low and high anthocyanin basil ( Ocimum basilicum) varieties (LAV and HAV) were sprayed with 4.8 mg Cu/per pot from Cu(OH) 2 nanowires, Cu(OH) 2 bulk (CuPro), or CuSO 4 and cultivated for 45 days. In both varieties, significantly higher Cu was determined in leaves of CuSO 4 exposed plants (691 and 672.6 mg/kg for LAV and HAV, respectively); however, only in roots of HAV, Cu was higher, compared to control ( p ≤ 0.05). Nanowires increased n-decanoic, dodecanoic, octanoic, and nonanoic acids in LAV, but reduced n-decanoic, dodecanoic, octanoic, and tetradecanoic acids in HAV, compared with control. In HAV, all compounds reduced eugenol (87%), 2-methylundecanal (71%), and anthocyanin (3%) ( p ≤ 0.05). In addition, in all plant tissues, of both varieties, nanowires and CuSO 4 reduced Mn, while CuPro increased chlorophyll contents, compared with controls ( p ≤ 0.05). Results suggest that the effects of Cu(OH) 2 pesticides are variety- and compound-dependent.

Onychomycosis is a common fungal infection in dermatology clinics. The commonly used diagnostic method, potassium hydroxide (KOH) direct microscopy, does not have a high-positive detection rate. Therefore, a new diagnostic method is needed to confirm onychomycosis. The objective of this research was to use fluorescent brightener 85 (FB 85), a new fluorescent reagent for fungi detection, and to evaluate this new method based on the diagnostic positive rate, accuracy and efficiency in suspected onychomycosis compared with the KOH method. Subungual debris was collected from clinically suspected onychomycosis cases and divided into two parts. The parts were examined by FB 85 and 10% KOH solution, respectively. In total, 108 patients with suspected onychomycosis were recruited. The positive rates of FB 85 and KOH were 88.9% and 55.6%, respectively. The patients showed significant statistical differences (P < .001). Compared with the KOH method, the FB 85 fluorescent method was an accurate and efficient method with a higher positive rate. This method could increase the diagnostic accuracy and efficiency of onychomycosis detection., (© 2017 Blackwell Verlag GmbH.)

This contribution investigates aluminium mobilization from main aluminium pools in soils, phyllosilicates and oxyhydroxides, by acidic and chelating exometabolites of common soil fungi Aspergillus niger and A. clavatus. Their exometabolites' acidity as well as their ability to extract aluminium from solid mineral phases differed significantly during incubation. While both strains are able to mobilize aluminium from boehmite and aluminium oxide mixture to some extent, A. clavatus struggles to mobilize any aluminium from gibbsite. Furthermore, passive and active fungal uptake of aluminium enhances its mobilization from boehmite, especially in later growth phase, with strong linear correlation between aluminium bioaccumulated fraction and increasing culture medium pH. We also provide data on concentrations of oxalate, citrate and gluconate which are synthesized by A. niger and contribute to aluminium mobilization. Compared to boehmite-free treatment, fungus reduces oxalate production significantly in boehmite presence to restrict aluminium extraction efficiency. However, in presence of high phyllosilicates' dosages, aluminium is released to an extent that acetate and citrate is overproduced by fungus. Our results also highlight fungal capability to significantly enhance iron and silicon mobility as these elements are extracted from mineral lattice of phyllosilicates by fungal exometabolites alongside aluminium., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Availability of Fe in soil to plants is closely related to the presence of humic substances (HS). Still, the systematic data on applicability of iron-based nanomaterials stabilized with HS as a source for plant nutrition are missing. The goal of our study was to establish a connection between properties of iron-based materials stabilized by HS and their bioavailability to plants. We have prepared two samples of leonardite HS-stabilized iron-based materials with substantially different properties using the reported protocols and studied their physical chemical state in relation to iron uptake and other biological effects. We used Mössbauer spectroscopy, XRD, SAXS, and TEM to conclude on iron speciation, size, and crystallinity. One material (Fe-HA) consisted of polynuclear iron(III) (hydr)oxide complexes, so-called ferric polymers, distributed in HS matrix. These complexes are composed of predominantly amorphous small-size components (<5 nm) with inclusions of larger crystalline particles (the mean size of (11 ± 4) nm). The other material was composed of well-crystalline feroxyhyte (δ'-FeOOH) NPs with mean transverse sizes of (35 ± 20) nm stabilized by small amounts of HS. Bioavailability studies were conducted on wheat plants under conditions of iron deficiency. The uptake studies have shown that small and amorphous ferric polymers were readily translocated into the leaves on the level of Fe-EDTA, whereas relatively large and crystalline feroxyhyte NPs were mostly sorbed on the roots. The obtained data are consistent with the size exclusion limits of cell wall pores (5-20 nm). Both samples demonstrated distinct beneficial effects with respect to photosynthetic activity and lipid biosynthesis. The obtained results might be of use for production of iron-based nanomaterials stabilized by HS with the tailored iron availability to plants. They can be applied as the only source for iron nutrition as well as in combination with the other elements, for example, for industrial production of "nanofortified" macrofertilizers (NPK).

A novel zinc (Zn) fertilizer concept based on Zn-doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthesized, their chemical composition was analyzed, and their nutrient release was studied in buffered solutions with different pH values. Uptake of Zn by barley (Hordeum vulgare cv. Antonia) was evaluated in short- (8 weeks), medium- (11 weeks), and long-term (28 weeks) experiments in quartz sand and in a calcareous soil enriched with Zn-doped Mg-Fe-LDHs. The Zn release rate of the Zn-doped Mg-Fe-LDHs was described by a first-order kinetics equation showing maximum release at pH 5.2, reaching approximately 45% of the total Zn content. The Zn concentrations in the plants receiving the LDHs were between 2- and 9.5-fold higher than those in plants without Zn addition. A positive effect of the LDHs was also found in soil. This work documents the long-term Zn release capacity of LDHs complying with a release-on-demand behavior and serves as proof-of-concept that Zn-doped Mg-Fe-LDHs can be used as Zn fertilizers.

Various bioactive natural products, like the aminocoumarin antibiotics novobiocin and coumermycin, exhibit an aromatic C-methyl group adjacent to a glycosylated phenolic hydroxyl group. Therefore, tailoring of basic phenolic scaffolds to contain the intricate C-methyl/O-glycosyl motif is of high interest for structural and functional diversification of natural products. We demonstrate site-selective 8-C-methylation and 7-O-β-d-glucosylation of 4,5,7-trihydroxy-3-phenyl-coumarin (1) by S-adenosyl-l-methionine dependent C-methyltransferase (from Streptomyces niveus) and uridine 5'-diphosphate glucose dependent glycosyltransferase from apple (Malus × domestica). Both enzymes were characterized and shown to react readily with underivatized 1. However, glucosylation of the ortho-hydroxyl group prevented C-methylation, probably by precluding an essential substrate activation through deprotonation of 7-OH. Therefore, dual modification was only feasible when C-methylation occurred strictly before O-glucosylation. The target product was synthesized in near quantitative yield (98% conversion) from 500 μM 1 and its structure was confirmed by NMR. Combination of C-methyltransferase and O-glycosyltransferase reactions for synthetic tailoring of a natural product through biocatalysis was demonstrated for the first time.

Layered double hydroxides (LDHs) used to recover P from wastewater have recently been proposed as new slow-release fertilizers. Here, the use of P-exchanged Mg-Al LDHs as powdered or granulated fertilizer is explored and compared with monoammonium phosphate (MAP), a fully water-soluble fertilizer, and with struvite, a recycled phosphate fertilizer with lower solubility. First, these three fertilizers were compared in a 100-day incubation experiment using P diffusion visualization and chemical analysis to assess P release from either granules or powdered fertilizer in three different soils. By the end of the incubation, 74-90% of P remained within the LDH granule, confirming a slow release. Second, a pot experiment was performed with wheat (Triticum aestivum) in an acid and a calcareous soil. The granular treatment resulted in a considerably higher P uptake for MAP compared to LDH and struvite. For the powder treatments, the P uptake was less than for granular MAP and was largely unaffected by the chemical form. The LDHs and struvite showed a lower agronomic effectiveness than granular MAP, but the benefits of their use in P recycling, potential residual value, and environmental benefits may render these slow-release fertilizers attractive.

Background: Mori Fructus and Mori Ramulus are two traditional Chinese herbal medicines from mulberries. The present work explores their beneficial effects on •OH-treated mesenchymal stem cells (MSCs) and discusses possible mechanisms., Methods: Lyophilized aqueous extracts of Mori Fructus (LAMF) and Mori Ramulus (LAMR) were prepared and analyzed using HPLC. LAMF and LAMR (along with morin) were further investigated for their effects on •OH-treated MSCs using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. The direct antioxidation mechanisms were studied using 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO•)-scavenging, 2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS + •)-scavenging and 1,1-diphenyl-2-picryl-hydrazl (DPPH•)-scavenging, as well as Cu 2+ -reducing and Fe 3+ -reducing antioxidant power. Finally, the indirect antioxidant mechanism was investigated based on the UV-vis spectra of Fe 2+ -chelation., Results: In each LAMF and LAMR, seven phytophenols were successfully measured by HPLC, including five flavonoids (morin, rutin, astragalin, isoquercitrin and luteolin) and two non-flavonoids (chlorogenic acid and maclurin). MTT assays revealed that LAMF, LAMR and morin could effectively increase the survival of •OH-treated MSCs at 10-100 μg/mL, and could effectively scavenge PTIO• (IC 50 6609.7 ± 756.6, 4286.9 ± 84.9 and 103.4 ± 0.9 μg/mL, respectively), DPPH• (IC 50 208.7 ± 3.0, 97.3 ± 3.1 and 8.2 ± 0.7 μg/mL, respectively) and ABTS + • (IC 50 73.5 ± 5.8, 34.4 ± 0.1 and 4.2 ± 0.2 μg/mL, respectively), and reduce Cu 2+ (IC 50 212.5 ± 7.0, 123.2 ± 0.9 and 14.1 ± 0.04 μg/mL, respectively) & Fe 3+ (IC 50 277.0 ± 3.1, 191.9 ± 5.2 and 5.0 ± 0.2 μg/mL, respectively). In the Fe 2+ -chelating assay, the five flavonoids produced much stronger shoulder-peaks than the two non-flavonoids within 420-850 nm., Conclusion: Mori Fructus and Mori Ramulus, can protect MSCs from •OH-induced damage. Such beneficial effects can mainly be attributed to the antioxidant action of phytophenols, which occurs via direct (ROS-scavenging) and indirect mechanism (Fe 2+ -chelating). The ROS-scavenging mechanism, however, include at least a H + -transfer and an electron-transfer (ET), and possibly includes a hydrogen-atom-transfer (HAT). In the Fe 2+ -chelating, flavonoids are more effective than non-flavonoids. This can be attributed to several adjacent planar chelating-sites between the 3-OH and 4-C = O, between the 4-C = O and 5-OH, or between the 3'-OH and 4'-OH in flavonoids. Such multiple-Fe 2+ -chelating reactions cause overlap in the UV-vis absorptions to deepen the complex color, enhance the peak strength, and form shoulder-peaks. By comparison, two non-flavonoids with catechol moiety produce only a weak single peak.

Adiponectin receptors (ADIPORs) are integral membrane proteins that control glucose and lipid metabolism by mediating, at least in part, a cellular ceramidase activity that catalyses the hydrolysis of ceramide to produce sphingosine and a free fatty acid (FFA). The crystal structures of the two receptor subtypes, ADIPOR1 and ADIPOR2, show a similar overall seven-transmembrane-domain architecture with large unoccupied cavities and a zinc binding site within the seven transmembrane domain. However, the molecular mechanisms by which ADIPORs function are not known. Here we describe the crystal structure of ADIPOR2 bound to a FFA molecule and show that ADIPOR2 possesses intrinsic basal ceramidase activity that is enhanced by adiponectin. We also identify a ceramide binding pose and propose a possible mechanism for the hydrolytic activity of ADIPOR2 using computational approaches. In molecular dynamics simulations, the side chains of residues coordinating the zinc rearrange quickly to promote the nucleophilic attack of a zinc-bound hydroxide ion onto the ceramide amide carbonyl. Furthermore, we present a revised ADIPOR1 crystal structure exhibiting a seven-transmembrane-domain architecture that is clearly distinct from that of ADIPOR2. In this structure, no FFA is observed and the ceramide binding pocket and putative zinc catalytic site are exposed to the inner membrane leaflet. ADIPOR1 also possesses intrinsic ceramidase activity, so we suspect that the two distinct structures may represent key steps in the enzymatic activity of ADIPORs. The ceramidase activity is low, however, and further studies will be required to characterize fully the enzymatic parameters and substrate specificity of ADIPORs. These insights into ADIPOR function will enable the structure-based design of potent modulators of these clinically relevant enzymes.

In the present study, we investigated oxidative stress parameters and antioxidant defence status in perinatal hypothyroid rat liver and heart. We found that the proteincarbonyl content did not differ significantly between the three groups both in the pup liver and in the heart. The OH˙ level was significantly decreased in the hypothyroid heart but not in the liver compared with controls. A slight but not significant decrease in SOD activity was observed in both perinatal hypothyroid liver and heart. A significantly increased activity of CAT was observed in the liver but not in the heart of hypothyroid pups. The GPx activity was considerably increased compared with controls in the perinatal hypothyroid heart and was unaltered in the liver of hypothyroid pups. We also found that vitamin E levels in the liver decreased significantly in hypothyroidism and were unaltered in the heart of perinatal hypothyroid rats. The GSH content was elevated significantly in both hypothyroid liver and heart. The total antioxidant capacity was higher in the liver of the hypothyroid group but not in the hypothyroid heart. Thyroxine replacement could not repair the above changes to normal. In conclusion, perinatal hypothyroidism modulates the oxidative stress status of the perinatal liver and heart.

In the present work, we describe a new thiamine amperometric biosensor based on thiamine pyrophosphate (ThDP)-dependent transketolase (TK)-catalyzed reaction, followed by the oxidative trapping of TK intermediate α,β-dihydroxyethylthiamine diphosphate (DHEThDP) within the enzymatic active site. For the biosensor design purpose, TK from Escherichia coli (TKec) was immobilized in Mg 2 Al-NO 3 Layered Double Hydroxides (LDH) and the electrochemical detection was achieved with the TKec/LDH modified glassy carbon electrode (GCE). The transduction process was based on the ability of Fe(CN) 6 3- to oxidize DHEThDP to glycolic acid along with ThDP regeneration. The released Fe(CN) 6 4- was re-oxidized at +0.5V vs Ag-AgCl and the reaction was followed by chronoamperometry. The TKec/LDH/GCE biosensor was optimized using the best TK donor substrates, namely l-erythrulose and d-fructose-6-phosphate. ThDP was assayed with great sensitivity (3831mAM -1 cm -2 ) over 20-400nM linear range., (Copyright © 2016 Elsevier B.V. All rights reserved.)

We report on the protonation state of Helicobacter pylori catalase compound II. UV/visible, Mössbauer, and X-ray absorption spectroscopies have been used to examine the intermediate from pH 5 to 14. We have determined that HPC-II exists in an iron(IV) hydroxide state up to pH 11. Above this pH, the iron(IV) hydroxide complex transitions to a new species (pK a = 13.1) with Mössbauer parameters that are indicative of an iron(IV)-oxo intermediate. Recently, we discussed a role for an elevated compound II pK a in diminishing the compound I reduction potential. This has the effect of shifting the thermodynamic landscape toward the two-electron chemistry that is critical for catalase function. In catalase, a diminished potential would increase the selectivity for peroxide disproportionation over off-pathway one-electron chemistry, reducing the buildup of the inactive compound II state and reducing the need for energetically expensive electron donor molecules.

The SLC4A11 gene encodes the bicarbonate-transporter-related protein BTR1, which is mutated in syndromes characterized by vision and hearing loss. Signs of these diseases [congenital hereditary endothelial dystrophy (CHED) and Harboyan syndrome] are evident in mouse models of Slc4a11 disruption. However, the intrinsic activity of Slc4a11 remains controversial, complicating assignment of its (patho)physiological role. Most studies concur that Slc4a11 transports H + (or the thermodynamically equivalent species OH - ) rather than HCO 3 - , but disparities have arisen as to whether the transport is coupled to another species such as Na + or NH 3 /NH 4 + Here for the first time, we examine the action of mouse Slc4a11 in Xenopus oocytes. We simultaneously monitor changes in intracellular pH, membrane potential, and conductance as we alter extracellular pH, revealing the electrical and chemical driving forces that underlie the observed ion fluxes. We find that mSlc4a11 is an ideally selective H + /OH - conductive pathway, the action of which is uncoupled from the cotransport of any other ion. We also find that the activity of mSlc4a11 is independently enhanced by both extracellular and intracellular alkalinization, suggesting OH - as the most likely substrate and providing a novel explanation for the apparent NH 3 -dependence of Slc4a11-mediated currents reported by others. We suggest that the unique properties of Slc4a11 action underlie its value as a pH regulator in corneal endothelial cells., (Copyright © 2016 the American Physiological Society.)

Objective: This study investigated the effect of passive ultrasonic irrigation (PUI) on diffusion of hydroxyl ions through radicular dentine., Materials and Methods: After chemomechanical preparation of root canals in 60 human teeth, the cementoenamel junction and the apical 3 mm of each root were covered with fast-setting adhesive. Four final irrigation protocols were applied (n = 10): group (G)1: irrigation with EDTA + NaOCl; G2: EDTA + PUI + NaOCl; G3: EDTA+(NaOCl + PUI); G4: (EDTA + PUI) + (NaOCl + PUI). Ten teeth irrigated with distilled water followed by PUI (G5) served as the negative control. After drying, the canals were filled with calcium hydroxide paste (CH), sealed and kept in individual vials containing 10 mL of distilled water with known pH values. At 7, 14, and 21 days, the pH of the water in the vials was measured. The pH values in various groups were analyzed with two-way ANOVA (irrigation protocol and time period as factors) and Holm-Sidak multiple comparison test (α = 0.05)., Results: Changes in pH was not significantly different among groups (P = 0.651) but was significant different among different time periods (P < 0.0001). For all groups, ion diffusion was higher at 14 and 21 days than at 7 days., Conclusions: PUI has no effect on diffusion of hydroxyl ions through radicular dentine. When CH is used as temporary filling material, a waiting period of at least 14 days is required to create an alkaline environment within the radicular dentine., Clinical Relevance: The use of PUI during final irrigation phase does not improve the action of CH when it is used as temporary filling material.

A laboratory study using a combined upflow anaerobic sludge bed (UASB) and aerobic and anoxic fixed-bed reactor system was undertaken to explore its capability for removing tetramethylammonium hydroxide (TMAH) and nitrogen from light-emitting diode wastewater. When the organic loading rate was maintained at 0.26-0.65 kg TMAH m(-3 )d(-1), the UASB reactor removed 70-100% of TMAH through methanogenesis. When the [Formula: see text] -N loading rate was maintained at 0.73-1.4 kg [Formula: see text]-N m(-3 )d(-1), the aerobic reactor oxidized 31-59% of [Formula: see text]-N to [Formula: see text]-N through nitritation. When the nitrogen loading rate was maintained at 0.42-0.75 kg N m(-3 )d(-1), the anoxic reactor removed 27-63% of nitrogen through anammox. The performance data of the combined reactor system agreed well with the stoichiometric relationships of methanogenesis, nitritation, and anammox. The batch studies showed that a higher initial TMAH concentration of up to 2520 mg L(-1) gave a higher methanogenic activity of up to 16 mL CH4 g(-1) VSS d(-1). An increase in the initial TMAH concentration of up to 500 mg L(-1) gradually decreased the activity of ammonia-oxidizing bacteria; whereas an increase in the initial TMAH concentration of up to 47 mg L(-1) imposed a marked inhibiting effect on the activity of anammox bacteria.

Cell migration and invasion are integral to lung cancer metastasis. In this study, we investigated the combination of traditional chemotherapy and a layered double hydroxide (LDH) carrier as a new strategy for the inhibition of migration and invasion. To investigate the characteristics and possible mechanisms of VP16-LDH [the Mg-Al/LDH containing etoposide (VP16)], we used several experimental techniques, such as transmission electron microscopy (TEM) and fluorescent microscopy. The TEM, X-ray diffraction (XRD) and zeta potential results indicated that VP16 binds well with LDH, with an average size of 70 nm, and the drug delivery system was confirmed to have the desired quality of slow release by the in vitro release test results. Fluorescent images showed that the cellular uptake of VP16-LDH was a caveolae-mediated and energy-dependent process. Moreover, A549 cells treated with VP16-LDH (5 μg/ml, 10 μg/ml) demonstrated significant inhibition of cell migration and invasion compared with the cells treated with free VP16 at the same concentration. The inhibition of AKT, mTOR and STAT3 phosphorylation and p-β-catenin up-regulation in VP16-LDH-treated cells revealed a possible molecular mechanism via the mTOR/AKT and STAT pathways, through which VP16-LDH had a stronger inhibitory effect on migration than the drug alone.