Diester Research Articles

Rapeseed meal processing and dietary enzymes modulate excreta inositol phosphate profile, nutrient availability, and production performance of broiler chickens

This study aimed to assess the effect of rapeseed meal (RSM) processing method, where solvent extraction occurred under standard industry conditions (ST) or cold-pressed hexane extraction was employed (MT), and exogenous enzyme supplementation (phytase [PHY] and xylanase [XYL]) alone or in combination on key nutritional factors of broiler chickens. A randomized control experiment was performed using 144 male Ross 308 broilers in a 2 × 2 × 3 factorial arrangement. Three diets including a nutritionally complete wheat-based basal diet (BD), a diet containing 200 g/kg of RSM extracted under ST and another diet containing 200 g/kg of RSM extracted under MT were produced. Each diet was then split into 4 parts and was fed as is, or supplemented with PHY at 1,500 FTU/kg or XYL at 16,000 BXU/kg, alone or in combination, resulting in 12 diets in total. Response criteria: feed intake (FI), weight gain (WG), and feed conversion ratio (FCR), from 7 to 21 d age, AMEn, retention coefficients for dry matter (DMR), nitrogen (NR), fat (FR), and the profile of inositol phosphate esters (IP2-6) and myo-inositol (MI) in excreta. Diets containing MT had higher AMEn compared to ST diets (P < 0.05). There was RSM by PHY interaction for FI, as only birds fed MT diet responded to PHY supplementation with reduced FI and FCR (P < 0.001). Feeding XYL reduced overall FI and FCR (P < 0.05). Feeding PHY reduced IP6 and increased MI in excreta (P < 0.001). Feeding XYL and PHY in combination reduced MI in excreta compared to PHY only (P = 0.05). Compared to BD, birds fed RSM diets had an increased IP6 (P < 0.05) and MI concentration in excreta (P < 0.01). This may be due to IP ester differences in RSM and BD.

Bonding Durability Between Zirconia and Different Types of Tooth or Implant Abutments—A Systematic Review. Part II: Outcomes of Clinical Studies

To systematically review all clinical studies focusing on the clinical outcomes of zirconia restorations bonded to different types of tooth or implant abutments and to provide practical clinical guidelines. A search was performed for English-language articles in dental journals published up to September 2020 using a combination of free-text words and MeSH terms. Studies were identified for review according to certain inclusion and exclusion criteria. A total of 2,856 studies were identified, and 24 studies were finally included. The included studies featured different types of surface pretreatment methods, primers, resin cements, tooth and implant abutments, zirconia restorations, and designs. The relatively limited number of identified studies and the heterogeneity of the extracted data did not allow for meta-analysis. Airborne-particle abrasion (APA) and tribochemical silica (TBS) APA surface pretreatment methods yielded positive clinical outcomes on zirconia/resin bonding to all types of tooth surfaces identified. Chemically activating the APA and the TBS APA zirconia surfaces with an MDP monomer-based primer, along with an MDP monomer or phosphoric ester monomer-based resin cement, seems to be a durable bonding protocol for all types of tooth surfaces identified. Skipping the surface pretreatment method step in the bonding protocol did not affect the clinical outcomes of certain types of zirconia restorations on most types of tooth or implant abutment surfaces identified. Type of resin cement seems to be a less influential factor.

CdS Quantum Dots as Potent Photoreductants for Organic Chemistry Enabled by Auger Processes.

Strong reducing agents (<-2.0 V vs saturated calomel electrode (SCE)) enable a wide array of useful organic chemistry, but suffer from a variety of limitations. Stoichiometric metallic reductants such as alkali metals and SmI2 are commonly employed for these reactions; however, considerations including expense, ease of use, safety, and waste generation limit the practicality of these methods. Recent approaches utilizing energy from multiple photons or electron-primed photoredox catalysis have accessed reduction potentials equivalent to Li0 and shown how this enables selective transformations of aryl chlorides via aryl radicals. However, in some cases, low stability of catalytic intermediates can limit turnover numbers. Herein, we report the ability of CdS nanocrystal quantum dots (QDs) to function as strong photoreductants and present evidence that a highly reducing electron is generated from two consecutive photoexcitations of CdS QDs with intermediate reductive quenching. Mechanistic experiments suggest that Auger recombination, a photophysical phenomenon known to occur in photoexcited anionic QDs, generates transient thermally excited electrons to enable the observed reductions. Using blue light-emitting diodes (LEDs) and sacrificial amine reductants, aryl chlorides and phosphate esters with reduction potentials up to -3.4 V vs SCE are photoreductively cleaved to afford hydrodefunctionalized or functionalized products. In contrast to small-molecule catalysts, QDs are stable under these conditions and turnover numbers up to 47 500 have been achieved. These conditions can also effect other challenging reductions, such as tosylate protecting group removal from amines, debenzylation of benzyl-protected alcohols, and reductive ring opening of cyclopropane carboxylic acid derivatives.

Characterization of Hydration Water Bound to Choline Phosphate-Containing Polymers

Zwitterionic methacrylate polymers with either choline phosphate (CP) (poly(MCP)) or phosphorylcholine (PC) (poly(MPC)) side groups were analyzed to characterize the bound hydration water molecules as nonfreezing water (NFW), intermediate water (IW), or free water (FW). This characterization was carried out by differential scanning calorimetry (DSC) of polymer/water systems, and the enthalpy changes of cold crystallization and melting were determined. The electron pair orientation of CP is opposite to that of PC, and the former binds the alkyl terminal groups at the phosphate esters. The numbers of NFW and IW molecules per monomer unit of poly(MCP) with an isopropyl terminal group were estimated to be 10.7 and 11.3 mol/mol, respectively, which were slightly greater than those of the poly(MCP) bearing an ethyl terminal group. More NFW and IW molecules hydrated the phosphobetaine polyzwitterions, poly(MCP) and poly(MPC), compared with carboxybetaine and sulfobetaine polymers. Moreover, the hydration states of polyelectrolytes were compared with the zwitterionic polymers. Finally, we discuss the relationship between the amount of hydration water and bio-inert properties.

Arabidopsis PFA-DSP-Type Phosphohydrolases Target Specific Inositol Pyrophosphate Messengers.

Inositol pyrophosphates are signaling molecules containing at least one phosphoanhydride bond that regulate a wide range of cellular processes in eukaryotes. With a cyclic array of phosphate esters and diphosphate groups around myo-inositol, these molecular messengers possess the highest charge density found in nature. Recent work deciphering inositol pyrophosphate biosynthesis in Arabidopsis revealed important functions of these messengers in nutrient sensing, hormone signaling, and plant immunity. However, despite the rapid hydrolysis of these molecules in plant extracts, very little is known about the molecular identity of the phosphohydrolases that convert these messengers back to their inositol polyphosphate precursors. Here, we investigate whether Arabidopsis Plant and Fungi Atypical Dual Specificity Phosphatases (PFA-DSP1-5) catalyze inositol pyrophosphate phosphohydrolase activity. We find that recombinant proteins of all five Arabidopsis PFA-DSP homologues display phosphohydrolase activity with a high specificity for the 5-β-phosphate of inositol pyrophosphates and only minor activity against the β-phosphates of 4-InsP7 and 6-InsP7. We further show that heterologous expression of Arabidopsis PFA-DSP1-5 rescues wortmannin sensitivity and deranged inositol pyrophosphate homeostasis caused by the deficiency of the PFA-DSP-type inositol pyrophosphate phosphohydrolase Siw14 in yeast. Heterologous expression in Nicotiana benthamiana leaves provided evidence that Arabidopsis PFA-DSP1 also displays 5-β-phosphate-specific inositol pyrophosphate phosphohydrolase activity in planta. Our findings lay the biochemical basis and provide the genetic tools to uncover the roles of inositol pyrophosphates in plant physiology and plant development.

Is the use of paper food contact materials treated with per- and polyfluorinated alkyl substances safe for high-temperature applications? – Migration study in real food and food simulants

Migration of per- and polyfluorinated alkyl substances (PFAS) from paper food contact materials (FCMs) can pose a consumer risk. However, risk assessment procedures typically do not consider PFAS contribution from FCMs. Moreover, migration studies are often limited to one subclass of PFAS or simplified by using food simulants (FS). To assess the risk comprehensively, migration of three PFAS subclasses (perfluorinated carboxylic acids/ sulfonic acids (PFCAs/PFSAs), polyfluoroalkyl phosphate esters (PAPs), and fluorotelomer alcohols (FTOHs)) from six FCMs were investigated to FS (50% and 20% ethanol) and food (oatmeal porridge, muffins, and tomato soup) under high-temperature conditions. Migration of PFCAs and FTOHs to all food samples was observed. Migration of PFCAs and FTOHs to 50% ethanol was significantly higher than migration to real food whilst FTOHs did not migrate into 20% ethanol. Estimated dietary PFAS exposure for children (1.06 – 5.67 ng/kgbw/day) exceeded EFSA’s proposed safety threshold (0.63 ng/kgbw/day), risking consumer health.

A self-assembly lanthanide nanoparticle for ratiometric fluorescence determination of alkaline phosphatase activity

Alkaline phosphatase (ALP) has been known to participate in the multiple pathways of cell metabolism. Here, a ratiometric fluorescent probe was designed for determination of ALP activity based on Ce-Tb@GMP. The Ce-Tb@GMP nanoparticles were prepared via the self-assembly of guanosine monophosphate (GMP) with terbium and cerium ions (Ce3+, Tb3+). The Ce-Tb@GMP nanoparticles own two luminescent centers, Tb and Ce, respectively. In presence of ALP, the phosphate ester in GMP was hydrolyzed and the structure of Ce-Tb@GMP was destroyed. Moreover, the coordination effect of Ce3+, Tb3+ and ligand GMP was significantly declined and the energy transfer efficiency from Ce3+, GMP to Tb3+ was reduced. Therefore, the fluorescence emission of Tb3+ and Ce3+ was quenched and the fluorescence intensity ratio (F552/F384) gradually decreased. This probe displayed low limit detection 0.12 mU/mL under the concentration range of 0.2–60 mU/mL. Meanwhile, the method accomplished the detection of ALP in a diluted serum sample of 5%. This strategy will make a construction for the application of fluorescent probes in bioanalytical sciences.

Covalent Adduct Formation in Methylthio-d-ribose-1-phosphate Isomerase: Reaction Intermediate or Artifact?

Methylthio-d-ribose-1-phosphate (MTR1P) isomerase (MtnA) functions in the methionine salvage pathway by converting the cyclic aldose MTR1P to its open-chain ketose isomer methylthio-d-ribulose 1-phosphate (MTRu1P). What is particularly challenging for this enzyme is that the substrate's phosphate ester prevents facile equilibration to an aldehyde, which in other aldose-ketose isomerases is known to activate the α-hydrogen for proton or hydride transfer between adjacent carbons. We speculated that MtnA could use covalent catalysis via a phosphorylated residue to permit isomerization by one of the canonical mechanisms, followed by phosphoryl transfer back to form the product. In apparent support of this mechanism, [32P]MTR1P was found by SDS-PAGE and gel-filtration chromatography to radiolabel the enzyme. Susceptibility of this adduct to strongly acidic and basic pH and nucleophilic agents is consistent with an acyl phosphate. C160S and D240N, mutants of two conserved active-site residues, however, exhibited no difference in radiolabeling despite a reduction in activity of ∼107, leading to the conclusion that phosphorylation is unrelated to catalysis. Unexpectedly, prolonged incubations with C160S revealed up to 30% accumulation of radioactivity, which was identified by 31P and 13C NMR to be the result of a second adduct─a hemiketal formed between Ser160 and the carbonyl of MTRu1P. These results are interpreted as indirect support for a mechanism involving transfer of the proton from C-2 to C-1 by Cys160.

Synthesis and biological evaluation of scutellarein derivatives as neuroprotective agents via activating Nrf2/HO-1 pathway

Oxidative stress has been considered as the main factor of neurodegenerative diseases. Activation of the Nrf2/HO-1 pathway, as one of the most crucial endogenous protection systems, was regarded as an effective strategy to against oxidative injury. Here, a series of phosphate esters or phosphonates of scutellarein derivatives were designed, synthesized and evaluated on SH-SY5Y cell lines to examine neuroprotective effects against H2O2 induced damage. Among them, compound 16d exhibited more potent cytoprotective effect than the lead compound scutellarin. Preliminary mechanism studies showed that compound 16d could prevent H2O2 induced neuronal apoptosis, significantly decrease ROS generation, elevate SOD and reduce MDA levels in a dose-dependent manner in SH-SY5Y cell lines. Furthermore, western blot assay disclosed that compound 16d could activate Nrf2, and increase the expression of its downstream genes HO-1 in a concentration-dependent manner, thus displaying potent neuroprotective activity. Overall, these findings demonstrated that compound 16d, as a promising neuroprotective agent, deserved further development.

Interactions of two phosphate ester monomers with hydroxyapatite and collagen fibers and their contributions to dentine bond performance

ObjectivesTo evaluate the interactions of two phosphate ester monomers [10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) and dipentaerythritol penta-acrylate phosphate (PENTA)] with hydroxyapatite and collagen and understand their influence on dentine bonding. MethodsFourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, nuclear magnetic resonance, ultraviolet-visible, and molecular docking were applied for separately evaluating the interactions of two monomers with hydroxyapatite and collagen. Hydrophilicity tests and morphological observation were employed to characterize pretreated dentine. Microtensile bond strength (μTBS) and nanoleakage were investigated to evaluate the bonding performance. Hydroxyproline assay, in situ zymography, and matrix metalloproteinase-9 (MMP-9) activity assay were used to confirm the MMP inhibition. ResultsChemoanalytic characterization confirmed the interactions of 10-MDP and PENTA with hydroxyapatite and collagen. The interactions of PENTA were weaker than 10-MDP. PENTA possessed better dentine tubule sealing after etching than 10-MDP. Dentine treated with PENTA was more hydrophilic than 10-MDP. 10-MDP and PENTA treating significantly increased the initial μTBS than the control group without primer conditioning. μTBS decreased significantly during aging, and the decrease was more severe in the PENTA group than 10-MDP. The 10-MDP and PENTA groups exhibited relatively less fluorescence than the control. The relative inhibition percentages of MMP-9 decreased in the order of 10-MDP–Ca salt, 10-MDP and PENTA. The 10-MDP, PENTA, and 10-MDP–Ca salt groups showed significantly lower hydroxyproline contents than the control. ConclusionsAlthough PENTA adsorbed on hydroxyapatite, it did not form a stable calcium salt. The interactions of 10-MDP with hydroxyapatite and collagen are different than those of PENTA. Clinical significanceThe sealing of dentinal tubules by PENTA and the inhibition of MMP by 10-MDP and its calcium salts contribute to improving the dentine bonding durability.

Transformation behaviour of salts composed of calcium ions and phosphate esters with different linear alkyl chain structures in a simulated body fluid modified with alkaline phosphatase

ABSTRACT Ceramic biomaterials have been used for the treatment of bone defects and have stimulated intense research on such materials. We have previously reported that a salt composed of calcium ions and a phosphate ester (SCPE) transformed into hydroxyapatite (HAp) in a simulated body fluid (SBF) modified with alkaline phosphatase (ALP), and proposed SCPEs as a new category of ceramic biomaterials, namely bioresponsive ceramics. However, the factors that affect the transformation of SCPEs to HAp in the SBF remained unclear. Therefore, in this study, we investigated the behaviour of calcium salts of methyl phosphate (CaMeP), ethyl phosphate (CaEtP), butyl phosphate (CaBuP), and dodecyl phosphate (CaDoP) in SBF with and without ALP modification. For the standard SBF, an X-ray diffraction (XRD) analysis indicated that these SCPEs did not readily transform into calcium phosphate. However, CaMeP, CaEtP, and CaBuP were transformed into HAp and octacalcium phosphate in the SBF modified with ALP; therefore, these SCPEs can be categorised as bioresponsive ceramics. Although CaDoP did not exhibit a sufficient response to ALP to be detected by XRD, it is likely to be a bioresponsive ceramic based on the results of morphological observations. The transformation rate for the SCPEs decreased with increasing size of the linear alkyl group of the phosphate esters. The rate-determining steps for the transformation reaction of the SCPEs were changed from the dissolution of the SCPEs to the hydrolysis of the phosphate esters with increasing size of the phosphate ester alkyl groups. These findings contribute to designing novel bioresponsive ceramic biomaterials.

P-Chloride-Free Synthesis of Phosphoric Esters: Microwave-Assisted Esterification of Alkyl- and Dialkyl Phosphoric Ester-Acids Obtained from Phosphorus Pentoxide

AbstractIt is a reasonable endeavour to replace P-chloride starting materials (e.g., POCl3) with greener and cheaper reagents. Our purpose was to start from phosphorus pentoxide, i.e. to utilize its reaction with alcohols in the preparation of (HO)2P(O)(OR) and HOP(O)(OR)2, and to convert the mixtures of the corresponding monoester and diester, so obtained, into the target trialkyl esters. Separate experiments showed that the monobutylphosphate undergo microwave (MW)-assisted esterification with butanol in the presence of [bmim][BF4] catalyst at 200 °C to afford dibutylphosphate in a selective manner (ca. 95%) that, in turn, may be converted into tributylphosphate by alkylation under MW irradiation. In this way, the mixtures of (HO)2P(O)(OR) and HOP(O)(OR)2 obtained by the practical reaction of phosphorus pentoxide and alcohol (ROH) could also be converted in two additional steps into the corresponding trialkyl esters. The three-step synthesis of trialkylphosphates starting from phosphorus pentoxide was also transformed in a one-pot (step 1: preparation of the monoester diester mixture, step 2: diesterification) and telescoping (step 3: triesterification) variation, avoiding the isolation and purification of the intermediates, and affording the triesters­ in 86–93% yields. The three- and two-step P-chloride-free methods developed are ‘green’ and of more general value.

Structural Remodelling of the Carbon‐Phosphorus Enzymatic Machinery by a Dual ATP‐Binding Cassette Module

Phosphorus (P) is an essential macronutrient that can be extracted from the environment by several metabolic pathways. In E. coli, phosphate deprivation activates the the 14‐cistron phn operon that encodes carbon‐phosphorus (C‐P) lyase. C‐P lyase confers the ability to extract phosphorus from a wide range of phosphonate compounds containing the chemically highly stable C‐P bond.1 Phosphonates are widespread in nature and due to their similarity to phosphate esters, have important applications in agriculture and biomedicine, as pesticides (glyphosate, RoundUp) and antibiotics, respectively. C‐P lyase catalyses a complex multi‐step pathway that directly depends on 10 of the encoded proteins (PhnGHIJKLMNOP). Of these, the PhnJ subunit was shown to be responsible for cleavage of the C‐P bond via a strict anaerobic glycyl radical mechanism that requires an iron‐sulphur (Fe4S4) cluster and S‐adenosyl methionine (SAM) for radical activation. Surprisingly, however, this mechanism was not immediately compatible with the crystal structure of a PhnGHIJ C‐P lyase core complex, which placed key residues at a significant distance, thus leaving a large gap in our understanding of the mechanism of phosphonate breakdown.2,3 The phn operon also encodes two ATP‐binding cassette (ABC) proteins with homology to the nucleotide‐binding domains of ABC transporters, PhnK and PhnL, for which no function has been assigned. Here, we present four high‐resolution (~2 Å), single‐particle cryo‐electron microscopy structures of 300+ kDa C‐P lyase complexes in several key, functional states. Together, these structures reveal how the PhnGHIJ core complex interacts with a unique double dimer of PhnK and PhnL subunits, in which PhnK, in a tight ATP‐bound conformation, bridges the core complex and PhnL. We also show using additional structures determined under ATP turnover conditions, that ATP hydrolysis in PhnK induces a dramatic remodelling of the core complex, leading to opening and large‐scale movement of several subunits. Moreover, we show that ATP hydrolysis and binding of both ABC subunits is required for growth of E. coli on phosphonate. Finally, we demonstrate that C‐P lyase in the closed state binds substrate at a metal‐binding site located at the interface between the PhnI and PhnJ subunits, and that ATP hydrolysis leads to a reorganisation of this active site in a way likely contributes to substrate/product exchange. In summary, we provide several novel insights into the elusive process of phosphonate breakdown by C‐P lyase in microorganisms and represent a solid structural basis for understanding the catalytic process. Our structural data also uncover a hitherto unknown configuration of ABCs in which two ABC dimers directly interact with each other that have broad implications for our understanding of the role of this module in biological systems.1. Metcalf, W. W. &amp; Wanner, B. L. Gene 129, 27‐32, (1993).2. Kamat, S. S., Williams, H. J., Dangott, L. J., Chakrabarti, M. &amp; Raushel, F. M. Nature 497, 132‐136, (2013).3. Seweryn, P. et al. Nature 525, 68‐72, (2015).

Synergistic inhibition properties and microstructures of self-assembled imidazoline and phosphate ester mixture for carbon steel corrosion in the CO2 brine solution

The synergistic effect of oleic imidazoline (OIM) and alkyl phosphate ester (APE) for corrosion inhibition of carbon steel in CO2-saturated brine solution was investigated by electrochemistry and weight loss measurements. The effectiveness of corrosion inhibition is correlated to their relative compact film of OIM and APE adsorbed on metal, which is further correlated to the self-assembled structure in solution and the adhesion parameters on the surface. The optimal ratio of OIM and APE for synergistic corrosion inhibition is equal to one. The adsorption of mixed inhibitors on the metal follows the Langmuir isotherm. OIM and APE with dominant hexagonal liquid crystals (H1) in the solution correlate to the incompact monolayer and bilayer on the steel surface. OIM/APE mixed corrosion inhibitor forms catanionic complexes with lamellar structure in solution, which correlates to compact film coverage on the metal surface and corrosion inhibition. The mechanism is further studied and correlated with their critical micelle concentration (CMC), surface tension, contact angle(θ), adhesion tension, and adhesion work (WA) in diluted solution and on the metal surface. The studies demonstrate that a correlation of corrosion inhibition to the self-assembly structure in solution and on the surface exists when the mixed surfactants are used as corrosion inhibitors.

Insight into soilless revegetation of oligotrophic and heavy metal contaminated gold tailing pond by metagenomic analysis

Soilless revegetation is an efficient way for gold tailing remediation, and micro-ecological environments in plant rhizosphere are important for vegetation establishment and pollution removal. In the present study, a field experiment of soilless revegetation has been carried out in a gold tailings pond, and the key genera and functional genes in the plant rhizosphere of gold mine tailings were revealed by metagenomics analysis. Soilless revegetation significantly decreased rhizosphere tailing pH from 8.54 to 7.43–7.87, reduced heavy metal (HM) concentration by 29.81–44.02% and enhanced the nutrient content by 50.30–169.50% averagely. Such improvements were strongly and closely correlated to microbial community and functional gene composition variation. The relative abundance of ecologically beneficial genus such as Actinobacteria (increased 9.7–18.8%) and functional genes involved in carbon, nitrogen and phosphorus cycling such as pyruvate metabolism (relatively increased 8.7–15.0%), assimilatory (increased to 1.44–2.08 times), phosphate ester mineralization (increased to 1.12–1.29 times) and phosphate transportation (increased to 1.28–1.85 times) were significantly increased. Moreover, the relative abundance of most As and Zn resistance genes were reduced, which may relate to the decrease of As and Zn concentration in the rhizosphere tailings. These results revealed the correlation among HM concentrations, microbial composition and functional genes, and provided clear strategies for improving gold mine tailing ecological restoration efficiency.

Improved Pyrolysis Performance of a Cyclic Phosphate‐Melamine Intumescent Fire‐Retardant Coating System Using Ceria as an Additive

AbstractIn this study, cyclic phosphate ester (PEA)‐melamine (MEL) epoxy fire‐retardant coatings were prepared using ceria (CeO2) as an additive. In addition, the effect of ceria on the fireproof performance of the fire‐retardant coatings was analyzed. PEA was prepared and characterized as a flame retardant and a hardener in the system. PEA was mixed with epoxy resin and ceria to produce the coatings, which were then characterized in terms of thermal stability, flame‐retardant performance, and smoke suppression property. Results showed that ceria can significantly improve the fire resistance of the coatings. Compared with the coating without ceria, the coating with 6 % ceria had 56 % lower peak of heat release rate and 61 % lower peak smoke production rate. Thermogravimetric analysis revealed that the addition of ceria improved the thermal stability of the coatings and increased the weight of the residual char to 43.5 %. The internal condition of the foam structure of the expanded residual char was studied using scanning electron microscope. The infrared spectrum of the residual char indicated that the introduction of ceria effectively promoted the formation of cross‐linked structures.

Inhibition of Quorum-Sensing Regulator from Pseudomonas aeruginosa Using a Flavone Derivative.

Quorum sensing (QS) is a cell-to-cell communication process that controls bacterial collective behaviors. The QS network regulates and coordinates bacterial virulence factor expression, antibiotic resistance and biofilm formation. Therefore, inhibition of the QS system is an effective strategy to suppress the bacterial virulence. Herein, we identify a phosphate ester derivative of chrysin as a potent QS inhibitor of the human pathogen Pseudomonas aeruginosa (P. aeruginosa) using a designed luciferase reporter assay. In vitro biochemical analysis shows that the chrysin derivative binds to the bacterial QS regulator LasR and abrogates its DNA-binding capability. In particular, the derivative exhibits higher anti-virulence activity compared to the parent molecule. All the results reveal the potential application of flavone derivative as an anti-virulence compound to combat the infectious diseases caused by P. aeruginosa.

Release of poly- and perfluoroalkyl substances from finished biosolids in soil mesocosms

Finished biosolids were collected and characterized from seven municipal water resource recovery facilities. Poly- and perfluoroalkyl substances (PFAS) for the 54 quantified in the biosolids ranged from 323 ± 14.1 to 1100 ± 43.8 µg/kg (dry weight basis). For all biosolids, greater than 75% of the PFAS fluorine mass was associated with precursors. Di-substituted polyfluorinated phosphate esters (diPAPs) were the most abundant PFAS identified in the biosolids. The total oxidizable precursor assay on biosolids extracts generally failed to quantify the amount of precursors present, in large part due to the fact that diPAPS were not fully transformed during the TOP assay. Outdoor biosolids column leaching experiments intended to simulate biosolids land application showed sustained PFAS leaching over the 6-month study duration. Perfluoroalkyl acid (PFAA) concentrations in leachate, when detected, typically ranged in the 10 s to 100 s of ng/L; no diPAPs were detected in the leachate. The PFAA leaching from the biosolids exceeded the PFAA mass initially present in the biosolids (typically by greater than an order of magnitude), but the cumulative PFAA mass leached did not exceed the molar equivalents that could be explained by transformation of quantified precursors. These results highlight the importance of PFAA precursors initially present in biosolids and their contribution to long term leaching of PFAAs from land-applied biosolids.

Phytic acid-based adhesion promoter for UV-curable coating: High performance, low cost, and eco-friendliness

In this work, aiming to enhancing the adhesion of UV-curable coatings to metal surface, a phytic acid based adhesion promoter with photo-curable group (PA-GMA) was designed and prepared via a ring opening reaction of phytic acid (PA) and glycidyl methacrylate (GMA) in aqueous solution. Via the adjustment of PA/GMA feeding ratios, a series of PA-GMA with different contents of photo-curable methacrylate group have been synthesized. The structure of the bio-based PA-GMA was verified using 1H NMR, FTIR and XPS spectroscopy. The developed PA-GMA could significantly improve the adhesion strength between UV-cured coatings and metal substrates, which was superior to that of commercial phosphate ester adhesion promoters. Accompanied by the significantly enhanced adhesion performance, outstanding corrosion protection properties were also demonstrated. This study offers a novel route to prepare an eco-friendly and low-cost adhesion promoter using natural compound and a new strategy to tackle adhesive failure in UV-curable coatings.

Synthesis of diaryl phosphates using orthophosphoric acid as a phosphorus source

This paper presents a new synthetic route for diaryl phosphate esters, which are traditionally synthesized from phosphorus oxychloride. Specifically, we report the synthesis of diaryl phosphates by the dehydrative condensation of orthophosphoric acid, a phosphorus source, with aromatic alcohols.