Oil-water partition coefficient preparation and detection in the dihydroartemisinin self-emulsifying drug delivery system.

BACKGROUND: The aim of the present study is to increase the solubility of dihydroartemisinin (DHA) using the self-emulsifying drug delivery system (SEDDS). METHODS: We first conducted solubility test and ternary phase diagram, then, in order to optimize the formulation of the DHA self-emulsifying agent, the design mixture method was selected in the design expert software. Next, optimal prescription validation and preliminary formulation evaluation were conducted. By comparing the oil-water partition coefficient in vitro, the improvement of the in vivo osmotic absorption of DHA via self-emulsification was evaluated. RESULTS: The optimal prescription ratio of oleic acid polyethylene glycol glyceride, polyoxyethylene hydrogenated castor oil, and diethylene glycol monoethyl ether in the DHA self-emulsifying preparation = 0.511:0.2:0.289 (w/w/w), with a drug-loading capacity of 26.3634 mg/g, solubility of 2.5448 mg/ml, and self-emulsification time of 230 s. The solubility self-emulsification was approximately 20.52 × higher in DHA than in the crude drug. The self-emulsification could improve DHA permeability and promoting in vivo DHA absorption. CONCLUSION: The DHA SEDDS could significantly improve DHA solubility and in vivo absorption.

Studies on Hydrophobic Silica/Silicone Rubber Composite Microspheres with Dual-Size Microstructures.

In this study, a series of microsphere composites were prepared by the hydrosilylation of nanospherical SiO2 and silicon rubber microspheres. The influence of different host-guest size ratios on the wettability of the SiO2/silicone rubber composite microspheres was explored. The structures and performance of the composite microspheres were investigated using scanning electron microscopy and contact angle testing. The results showed that the prepared SiO2/silicone rubber composite microspheres had a raspberry-like structure and exhibited a rose petal effect. When the SiO2 content was 30%, the water contact angle of the SiO2/silicone rubber composite microspheres reached a maximum, and 30% was used as the optimal ratio for compounding SiO2 having different particle diameters with silicone rubber microspheres. Wettability calculations and analyses were performed for the surface with the composite microspheres. The results indicated that the structure with dual-size roughness could significantly improve surface hydrophobicity. As the ratio of the host-guest size increased, the contact angle of the water phase also increased. However, the surface structures of the composite microspheres were not uniform because of the surface chemical composition and the uncontrollable distribution of the small spheres on the surface of the large spheres during compounding. As a result, water droplets appeared in the Cassie-impregnated state on the composite microsphere particle coating, resulting in the phenomenon of high hydrophobicity and high adhesion.

Exploring dynamics and associations of dominant lignocellulose degraders in tomato stalk composting.

The plant residues of tomato bring pressures to the environment and composting provides a feasible method to treat such agricultural waste. However, little is known about the succession and associations of the dominant lignocellulose degraders in the compost system. To further accelerate the process by inoculating key functional microorganisms, a compost pile composed of tomato stalk with maize straw addition was constructed, and the whole community structure and functions of the dominant were investigated by applying the integrated mata-omics. Results showed that Actinobacteria, Firmicutes, and Ascomycota dominated and drove the assembly of the co-occurrence network. In the thermophilic stage, Thermobifida was the exclusive degrader of cellulose, and Thermobifida fusca was the most important cellulolytic actinomycete. Saccharomonospora viridis, Planifilum fulgidum, Thermobacillus sp. and the dominant ascomycota of Aspergillus sclerotialis participated in hemicellulose decomposing. In the cooling phase, functional microorganisms became more diverse, with Nocardiopsis flavescens, Glycomyces artemisiae, Glycomyces sambucus, Streptomyces rubrolavendulae and Streptomyces vietnamensis joining the cellulose-degrading rank, and Chaetomium thermophilum emerging as the main hemicellulose degrader. More than two thirds of the bacteria-bacteria interactions and all the fungi-fungi associations were positive, while, both competition (for the same substrate of hemicellulose) and synergy (preference for cellulose and hemicellulose) coexisted in the bacteria-fungi interactions. In conclusion, these findings provide useful information for understanding the biodegradation of tomato plant residues better, and effects of the functional agents identified on composting process should be further studied.

Self-catalytic polymerization of a water-soluble selenium/polypyrrole nanocomposite and its nonlinear optical properties.

A facile one-step method for the synthesis of a water-soluble selenium/polypyrrole (Se/PPy) nanocomposite was developed. In the aqueous synthesis process, the pyrrole acted as a reductant for the reduction of H2SeO3, and then the elemental Se formed in situ acted as a catalyst for the polymerization of pyrrole. The characterization results show that the as-obtained composite (Se/PPy) is a spherical (Φ80 nm) product that is made up of amorphous Se particles coated by PPy layers. The formation mechanism and influence factors of the products were discussed, based on a series of experiments. It is proposed that remainder H2SeO3 adsorbed on the PPy chains increased the water-solubility and conductivity of the Se/PPy nanocomposite. Significantly, relying on the synergistic effect of photo-conductive Se nanoparticles and electric-conductive PPy molecules, the Se/PPy nanocomposite possesses a large two-photon absorption (2PA) cross-section and good optical limiting properties, which were demonstrated by the Z-scan technique using a femtosecond laser. We believe that this work should be an interesting strategy for developing polymer composites with excellent optoelectrical properties.

Conductive elastomers with autonomic self-healing properties.

Healable, electrically conductive materials are highly desirable and valuable for the development of various modern electronics. But the preparation of a material combining good mechanical elasticity, functional properties, and intrinsic self-healing ability remains a great challenge. Here, we design composites by connecting a polymer network and single-walled carbon nanotubes (SWCNTs) through host-guest interactions. The resulting materials show bulk electrical conductivity, proximity sensitivity, humidity sensitivity and are able to self-heal without external stimulus under ambient conditions rapidly. Furthermore, they also possess elasticity comparable to commercial rubbers.

Design and Application Strategies of Natural Polymer Biomaterials in Artificial Ovaries.

For certain types of cancer patients, ovarian transplantation has a risk of malignant cancer cell infection. However, the autologous transplantation of an artificial ovary is safe and effective, guarantees the normal development of isolated follicles, regular oocyte maturation, and ovulation, partially restores endocrine function, and enables the patient to regain reproductive ability. Despite the complexity of the natural ovary, some progress has been made in the repair or replacement of reproductive tissues with the use of various biomaterials. This article reviews the physical structure, biomechanical properties, design elements, preparation routes, construction and practical use of natural polymer materials, usually hydrogel scaffolds, such as alginate, fibrin, gelatin, collagen, agarose, and acellular ovarian matrix in the preparation of artificial ovaries. We summarize how these materials can be made into artificial ovaries to achieve the conditions for fertility through follicle and oocyte development and identify several major issues to overcome for the future development of artificial ovaries, including how to establish blood recirculation, and how to establish hormone synthesis and release channels. This review is intended to provide a reference for the use of natural polymer biomaterials in reproductive clinics.

Childhood-onset primary Sjögren's syndrome in a tertiary center in China: clinical features and outcome.

OBJECTIVES: To characterize the clinical features and outcomes of childhood-onset primary Sjögren's syndrome (pSS). METHODS: Patients less than 18 years old who were diagnosed with pSS by paediatric rheumatologists were included, and all patients were applied the 2002 American-European Consensus Group (ACEG) criteria, the 2016 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria for pSS, or the 1999 proposed juvenile pSS criteria. The electronic medical records of patients with pSS from 2013 to 2020 were collected and analysed. RESULTS: Thirty-nine patients were included. Of them, 27 (69.2%), 38 (97.4%) and 35 (89.7%) patients fulfilled the AECG criteria, ACR/EULAR criteria and proposed juvenile pSS criteria, respectively. The female:male ratio was 3.9:1. The median ages at first signs or symptoms and at diagnosis were 9.2 (4.7, 14.5) years and 10.9 (6.3, 15.0) years, respectively. The main clinical manifestations were rash or purpura (20, 51.3%), followed by fever (12, 30.8%), glandular enlargement/recurrent parotitis (10, 25.6%), and dry mouth and/or dry eyes (9, 23.1%). Twenty-eight (56.4%) patients had systemic damage, the most common of which was haematological involvement (14, 35.9%), followed by hepatic (13, 33.3%) and renal involvement (8, 20.5%). Thirty-eight (97.4%) patients underwent labial minor salivary gland biopsy, and all exhibited focal lymphocytic sialadenitis. All patients had a global ESSDAI score ≥ 1 at diagnosis, and the median total score at diagnosis was 8 (2, 31). Thirty-six (92.3%) patients were followed up for a median time of 23.6 (7.9, 79.5) months, and three patients developed systemic lupus erythematosus (SLE) at follow-up times of 13.3, 38.8 and 63.8 months. CONCLUSIONS: The presentation of childhood-onset pSS is atypical, and extraglandular manifestations and systemic involvement are more common than in adult-onset pSS. Labial salivary gland biopsy is vital for patients with probable pSS. Some patients may develop SLE over time.

Metal-organic cage incorporating thin-film nanocomposite membranes with antifouling properties.

We report the antifouling properties of thin-film nanocomposite (TFN) membranes containing two water-stable metal-organic cages (MOCs). The MOC-containing TFN membranes possess excellent antifouling properties against positively-charged foulants and protein (BSA, up to 99.7% water permeability retention) and achieve up to 100% water permeability recovery.

The Effects of a Novel Curcumin Derivative Loaded Long-Circulating Solid Lipid Nanoparticle on the MHCC-97H Liver Cancer Cells and Pharmacokinetic Behavior.

Purpose: The objective of this study was to develop long-circulating solid lipid nanoparticles (LSLN) containing a novel curcumin (CU) derivative (CU1), to improve CU1's pharmacokinetic behavior and its anti-cancer effects in MHCC-97H liver cancer cells. Methods: LSLN loaded with CU1 (CU1-LSLN) was optimized and characterized. The cell biological properties and the anti-cancer mechanism of CU1-LSLN on MHCC-97H cells were evaluated by MTT, flow cytometry, Transwell, and Western blot. CU1-LSLN was further evaluated for pharmacokinetic behavior, biodistribution, and liver toxicity in SD rats. Results: The optimized CU1-LSLN formulation showed the ideal particle size (PS), polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (EE%), and drug loading (DL%) of 122.10 ± 6.63 nm, 0.19 ± 0.02, -36.30 ± 1.25 mV, 94.98 ± 0.90% and 4.53 ± 0.69%, respectively. X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectrometry (FTIR) indicated that CU1 was well encapsulated by LSLN and existed in amorphous form. Storage stability of CU1-LSLN was up to 180 days with a sustained-release of drug over 96 h. The uptake efficiency of CU1-LSLN to MHCC-97H cells was 3.24 and 2.98 times higher than that of CU and CU1 after treatment for 3 h, which helped to enhance the inhibitive effect of CU1-LSLN on the proliferation, migration, and invasion potential of MHCC-97H cells and increased its ability to promote apoptosis. Meanwhile, the expression levels of NF-κB, COX-2, MMP-2, MMP-9, and uPA decreased significantly. In vivo, CU1-LSLN prolonged the retention time of the drug, the area under the curve (AUC) increased significantly (CU: 69.9-fold, CU1: 85.9-fold), and no significant liver toxicity was observed. Conclusion: CU1-LSLN is a novel preparation with great potential for treating liver cancer.

Suppression of epidermal growth factor receptor (EGFR) expression by small hairpin RNA inhibits the growth of human nonsmall cell lung cancers bearing wild-type and mutant EGFR.

In the present study, we have used plasmid-based RNA interference (RNAi) strategy to downregulate the expression of epidermal growth factor receptor (EGFR) in EGFR wild-type (H292) and mutant (H1975) lung tumor models. The targeted knockdown of EGFR by small hairpin RNA not only inhibited growth of H292 xenograft but also inhibited H1975 lung cancer cell and xenograft, which bore L858R/T790M EGFR and was resistant to EGFR tyrosine kinase inhibitors. These data demonstrated that small hairpin RNA was an effective therapy against mutant EGFR-expressing cancer cells and thus considered to be a promising strategy in the treatment of lung cancers.

Porous polymers from octa(amino-phenyl)silsesquioxane and metalloporphyrin as peroxidase-mimicking enzyme for malathion colorimetric sensor.

Rapid and efficient pesticide detection methods are particularly important due to the growing problems of pesticide residues. Here, a new azo-based porous organic polymer, Azo(Fe)PPOP, was prepared from octa(amino-phenyl)silsesquioxane (OAPS) and iron(III) 5,10,15,20-tetrakis(4-nitrophenyl)porphyrin (FeTPP(NO2)4) via a simple coupling reaction without the participation of metal catalysts. The inorganic cage units of OAPS endowed Azo(Fe)PPOP a porous framework, high surface area, favorably thermal and chemical stability. In Azo(Fe)PPOP, iron(III) porphyrin units were individually isolated in a fixed location, which could effectively avoid dimerization or self-oxidation as happens as in the case of porphyrin monomers. Such a unique structure made Azo(Fe)PPOP exhibit an excellent peroxidase-like catalytic performance in the presence of H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB). Because of these advantages, we established a selective, facile, and sensitive colorimetric platform for direct detection of malathion within a very short time (3 min) with a low detection limit (8.5 nM). In addition, the recognition mechanism between Azo(Fe)PPOP and malathion was verified using X-ray photoelectron spectroscopy spectra. The practicality of the constructed platform was further executed by the detection of the pesticide in soil and food samples.

Organocatalytic enantioselective hydroxymethylation of oxindoles with paraformaldehyde as C1 unit.

A bifunctional thiourea-tertiary amine-catalyzed asymmetric hydroxymethylation of 3-substituted oxindoles using paraformaldehyde as the C1 unit was developed. A wide scope of oxindoles, bearing C3 sterically congested quaternary carbon centers, were smoothly obtained in good to excellent yields (up to 99%) and high enantioselectivities (up to 91% ee) under mild reaction conditions. A more significant feature of this approach employs cheap and readily available paraformaldehyde as a hydroxymethylation C1 unit, which is activated by chiral bifunctional thiourea organocatalysts.

Bacterial Detection and Elimination Using a Dual-Functional Porphyrin-Based Porous Organic Polymer with Peroxidase-Like and High Near-Infrared-Light-Enhanced Antibacterial Activity.

The efficient fabrication of multifunctional nanoplatforms for bacterial detection and elimination is of great importance in nanobiotechnology. A new porphyrin-based porous organic polymer, FePPOPBFPB, was synthesized via the reaction between pyrrole and 4-{2,2-bis[(4-formylphenoxy)methyl]-3-(4-formylphenoxy) propoxy} benzaldehyde (BFPB). The C-centric tetrahedral structure of BFPB promoted the formation of FePPOPBFPB with a 3D interconnected porous structure, high specific surface area, and plentiful surface catalytic active sites. The adjustable structural alkyl chain also enhanced the absorption capability of FePPOPBFPB in the long-wavelength visible and near-infrared regions (NIR). FePPOPBFPB exhibited excellent peroxidase-like activity toward a representative peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB) with H2O2. Utilizing these features, a rapid and visual detection of Staphylococcus aureus (S. aureus) based on FePPOPBFPB was established and exhibited high sensitivity and stability. Combining the catalysis with near-infrared-light (NIR) absorption, FePPOPBFPB can effectively catalyze the decomposition of biologically relevant concentrations of H2O2 to produce vast amounts of •OH radicals via the photo-Fenton reaction, which avoids the utilization of high toxic concentrations of H2O2. On the basis of these satisfactory features, FePPOPBFPB had a conspicuous bactericidal performance against S. aureus under NIR irradiation. To our knowledge, this is the first example of a porphyrin-based porous organic polymer antibacterial agent. The main reactive oxygen species (ROS) produced in this system and the possible antibacterial mechanism of FePPOPBFPB was also proposed through a series of experiments.

Visible-light-driven photo-Fenton degradation of organic pollutants by a novel porphyrin-based porous organic polymer at neutral pH.

Developing novel heterogeneous photo-Fenton catalysts with high efficiency and stability, driven by visible-light rather ultraviolet light at neutral pH has been a major challenge for degradation of organic pollutants. In this work, we successfully synthesized a metalloporphyrin-based porous organic polymer (FePPOP-1) by the Sonogashira cross-coupling reaction. UV-vis absorption spectra showed FePPOP-1 exhibits a significant coverage of the natural solar irradiance spectrum. As a result, the prepared FePPOP-1 has a significantly enhanced photocatalytic activity for the visible-light-driven degradation of methylene blue. By using only 4 mg of FePPOP-1 as a catalyst, it was found that 50 mL of organic wastewater containing 70 ppm MB could be totally degraded in 80 min even at neutral pH. The effects of the initial MB, H2O2 concentrations, pH value and common ions on MB degradation were studied in detail. Both the catalytic mechanism of FePPOP-1 and the degradation route of MB were also proposed.

Simultaneous removal of methylene blue and Pb2+ from aqueous solution by adsorption on facile modified lignosulfonate.

In this paper, simultaneous removal of methylene blue (MB) and Pb2+ from the binary component system by an easily prepared cross-linked lignosulfonate bio-adsorbent (CLLS) was described. CLLS was characterized by FTIR, SEM/EDS and TGA. The influences of pH, temperature, contact time and initial MB and Pb2+ concentrations on the adsorption performance were investigated. The results demonstrated a good ability of CLLS to remove MB and Pb2+ simultaneously. Using of 1.0 g L-1 loading, removal efficiency of MB and Pb2+ reached 98.0% and 97.8%, respectively, in the MB (100 mg.L-1)-Pb2+ (50 mg.L-1) system. Moreover, the adsorption isotherms and adsorption kinetics indicated that the results were fitting well with the Langmuir and pseudo-second-order model, respectively, for both MB and Pb2+. Based on the Langmuir model, the maximum adsorption capacity of MB and Pb2+ reached 132.6 and 64.9 mg g-1, respectively, in the MB-Pb2+ system, which was much lower than that in the single component system (358.4 mg g-1 100.9 mg g-1 for MB and Pb2+, respectively). Hence, simultaneous adsorption of MB and Pb2+ onto CLLS was an antagonistic adsorption. In addition, an apart-sequential adsorption method was used to study the action of adsorption sites on CLLS for MB and/or Pb2+ with the help of an efficient self-made apparatus. Rudimental results showed that there would be three different kinds of adsorption sites on CLLS: MB-site, Pb2+-site and MB/Pb2+- shared sites. Furthermore, in the MB (100 mg.L-1)-Pb2+(50.0 mg.L-1) system, the simultaneous removal efficiency of MB and Pb2+ still maintained 91.8% and 85.0%, respectively, after 6 cycles.

Combination of Curcumin and Paclitaxel Liposomes Exhibits Enhanced Cytotoxicity Towards A549/A549-T Cells and Unaltered Pharmacokinetics.

Background: Combination chemotherapy of chemo-drugs and natural herbal drugs has been shown to be more advantageous than individual treatment with respect to enhancing cytotoxicity, alleviating toxicity and controlling the development of multidrug resistance (MDR). Purpose: The goal of this study is to construct a combined drug delivery system of curcumin liposomes (CUR-LPs) and paclitaxel liposomes (PTX-LPs) to enhance the anticancer activity and reverse the MDR of PTX. Methods: CUR-LPs and PTX-LPs were prepared by solvent evaporation method with optimal formulation composition. MTT assay was used to assess the effect of the combination of CUR-LPs and PTX-LPs treatments on the proliferation of A549/A549-T cells. In addition, the pharmacokinetic behaviors of the combination treatments were evaluated by HPLC. Results : The mixed liposomes were found to have negative zeta-potential (-17.91 ± 1.21 mV) and relatively uniform particle size (105.88 ± 3.19 nm) with a low polydispersity index (0.21 ± 0.016). IC50 of PTX for combination of CUR-LPs and PTX-LPs decreased in the range of 1.47-2.9 times and 1.59-2.5 times compared to the free-drug counterparts in A549 and A549-T cells, respectively. Superior cytotoxicity and higher synergy (CI< 0.4) were observed for the combination treatment with ratio of 40:1 (CUR-LPs:PTX-LPs) compared with the free-drug counterparts in both cell lines tested. Following intravenous administration in rats, liposomes presented higher bioavailability (CUR-LPs: 9.02 fold; PTX-LPs: 7.32 fold) compared to free drugs. Co-administration did not alter the respective pharmacokinetic behaviors. Conclusion: Overall, the present study presents a promising strategy for the development of compound formulations of CUR and PTX.

Polylactide-glycoli acid and rapamycin coating intraocular lens prevent posterior capsular opacification in rabbit eyes.

OBJECTIVES: Posterior capsular opacification (PCO) is caused by the proliferation and migration of residual lens epithelium cells (LECs) after extracapsular cataract extraction (ECCE). Rapamcin (RAPA) is known to be a potent immunosuppressive drug with anti-inflammatory and anti-proliferative effects. The aim of this study was to investigate the safety and efficacy of rapamycin sustained release from modified intraocular lens (IOLs) in the prevention of PCO in rabbits. METHODS: Three types of IOLs were used, including the original IOL without modification, IOL with polylactide-glycoli acid (PLGA) coating (PLGA-IOL), and RAPA-loaded PLGA-IOL (RAPA-PLGA-IOL). Sixty New Zealand albino rabbits undergoing phacoemulsification in left eyes were randomly and equally divided into three groups. Group A was implanted with the original IOLs, group B was implanted with the PLGA-IOLs, and group C was implanted with the RAPA-PLGA-IOLs. All of the 60 treated left eyes were examined by a slit-lamp microscope. The concentrations of RAPA in the aqueous humor and blood were determined by high-performance liquid chromatography (HPLC), indicating an vivo release of drug from the polymer carrier. Anterior segment tissue was histologically examined, and wet posterior capsules were weighed. Six months after intervention the PCO was graded. RESULTS: The mean concentrations of RAPA in the aqueous humor from group C at 2 h, 1 days, 3 days, and 7 days after operation were 12.81 +/- 1.27 microg/ml, 14.57 +/- 0.99 microg/ml, 6.39 +/- 0.95 microg/ml, and 1.10 +/- 0.32 microg /ml respectively. The concentrations of RAPA in blood were undetectable. During the early days after the operation, the reactions of the anterior chamber from groups A and B were more severe than from group C. Our findings showed that the initial appearance of PCO in group C was much later than in the other two groups. The wet posterior capsules were weighed to be 0.3735 +/- 0.0943 g (group A), 0.3754 +/- 0.1093 g (group B), and 0.0432 +/- 0.0089 g (group C). Histological observation showed a similar phenomenon, that there was remarkably less accumulation of lens materials on the posterior capsules in group C than in the other two groups. CONCLUSION: Our findings suggest that the designed RAPA-PLGA-IOL effectively prevented formation and development of PCO for a relatively long duration.

Facile strategy to prepare a metalloporphyrin-based hydrophilic porous organic polymer with enhanced peroxidase-like activity and high stability for colorimetric detection of H2O2 and glucose.

Nanozymes, nanomaterial-based artificial enzymes, have attracted researchers' enormous interest due to their unique properties compared with natural enzymes. To mimic the catalytic function of natural enzymes, designing high-efficient, novel nanozymes is crucial yet challenging task. In this article, we described the synthesis and functions of a metalloporphyrin-based porous organic polymer, namely FePPOPs-SO3H. FePPOPs-SO3H was synthesized effortlessly via an extensive aromatic electrophilic substitution and the following sulfonation reactions. This strategy was cost-efficient without the participation of precious metal catalysts. The resultant FePPOPs-SO3H is intriguing since the framework itself is constructed by covalently linked porphyrin units, which could serve as a built-in catalyst and strengthen the stability of polymer. With sulfonic acid side groups, FePPOPs-SO3H is well water-dispersive. Owing to these unique characteristics, FePPOPs-SO3H exhibited excellent peroxidase-like activity toward a classical peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue product only within 20 s. The peroxidase-mimicking performance of FePPOPs-SO3H outperforms the ferric porphyrin monomer and normal Fe3O4 nanoparticles. Based on the excellent catalytic activity of FePPOPs-SO3H, two visual colorimetric sensors for ultrafast detecting H2O2 and glucose, respectively, were constructed with a wide linear range of 50-1800 µM (for H2O2) and 200-1500 µM (for glucose), as well as a relative lower limit of detection (LOD) [26.70 µM (for H2O2) and 16.38 µM (for glucose)]. Our strategy highlights opportunities for the design of new metalloporphyrin-based porous organic polymers with built-in catalytic skeletons and inherently excellent peroxidase-mimicking performance.

Immobilized lignin peroxidase on Fe3O4@SiO2@polydopamine nanoparticles for degradation of organic pollutants.

Lignin peroxidase (LiP) was obtained from Pichia methanolica through heterologous expression. LiP was extracted, purified, and immobilized on Fe3O4@SiO2@polydopamine (PDA) nanoparticles to acquire immobilized LiP. The optimal preparation conditions for immobilized LiP were investigated. Results showed that the immobilization efficiency of immobilized LiP reached 56.37% when the enzyme amount, PDA concentration, and immobilization time were 12 mg, 1.6 mg/mL, and 12 h, respectively. Compared with free LiP, the immobilized LiP showed good thermal stability and storage stability and improved pH tolerance. It also retained more than 30% of its initial activity after 8 cycles, demonstrating its improved reusability. The immobilized LiP demonstrated efficacy of reaction of 100%, 100%, 100%, 100%, 79%, 73%, and 65% for tetracycline, dibutyl phthalate, 5-chlorophenol, phenol, phenanthrene, fluoranthene, and benzo(a)pyrene, respectively, while the inactivated immobilized LiP only adsorbed <25% of phenanthrene and fluoranthene. The dissipation of organic pollutants was a combination of degradation and adsorption, with the former playing a more important role.

A unique meadow of the marine angiosperm Zostera japonica, covering a large area in the turbid intertidal Yellow River Delta, China.

Marine submerged aquatic angiosperms (seagrasses) are declining globally. The species Zostera japonica Asch. & Graebn. is endangered in its native range in Asia, but has been successfully introduced to North America. A large area (1031.8 ha) of Z. japonica meadow has recently been discovered in the intertidal zone of Yellow River Delta, China. This seagrass occurs along both sides of the river mouth, forming dense meadows in turbid water conditions. Seasonal investigations over two years were conducted to examine the distribution, biomass, seed reproduction, seed bank, and population recruitment of the seagrass meadows at three sites in the intertidal zone. The meadows generally showed relatively high coverage, biomass, reproductive effort, and seed production in August. The seed bank was found to be large and contributed to population recruitment. There were significant inter-annual variations overall, and at individual sites. These variations are likely due to winter temperatures, which determine the abundance of overwintering shoots and seedling success. Differences in micro-topography may also play a role in producing variations in seedling success between sites. Microsatellite analysis revealed a high genetic exchange between the two sides of the river mouth. The results indicate that the seagrass bed in the Yellow River Delta shallow waters is in good condition, which can be attributed to its location within a national nature reserve. Establishment of protected areas might act as an effective way to mitigate the anthropogenic disturbance, conserve the seagrass meadows, and then enhance critical ecosystem functions.