An iron-containing POM-based hybrid compound as a heterogeneous catalyst for one-step hydroxylation of benzene to phenol.

It is a major challenge to perform one-pot hydroxylation of benzene to phenol under mild conditions, which replaces the environmentally harmful cumene method. Thus, finding highly efficient heterogeneous catalysts that can be recycled is extremely significant. Herein, a (POM)-based hybrid compound {[FeII(pyim)2(C2H5O)][FeII(pyim)2(H2O)][PMoV2MoVI9VIV3O42]}·H2O (pyim = 2-(2-pyridyl)benzimidazole) (Fe2-PMo11V3) was successfully prepared by hydrothermal synthesis using typical Keggin POMs, iron ions and pyim ligands. Single-crystal diffraction shows that the Fe-pyim unit in Fe2-PMo11V3 forms a stable double-supported skeleton by Fe-O bonding to the polyacid anion. Remarkably, due to the introduction of vanadium, Fe2-PMo11V3 forms a divanadium-capped conformation. Benzene oxidation experiments indicated that Fe2-PMo11V3 can catalyze the benzene hydroxylation reaction to phenol in a mixed solution of acetonitrile and acetic acid containing H2O2 at 60 °C, affording a phenol yield of about 16.2% and a selectivity of about 94%.

MoO42--templated Ln20Ni21 heterometallic clusters with large low-field magnetic entropy.

The anionic template method is an effective strategy for synthesizing high-nuclearity transition-lanthanide (3d-4f) heterometallic clusters. Herein, two lanthanide clusters with formulas [Gd20Ni21(µ3-OH)21(CO3)6(IDA)21(C2H4NO2)6(C2O4)3(MoO4)1.5(µ2-OH)1.5(H2O)9]Cl10.5·79H2O (1) and [Tb20Ni21(µ3-OH)21(CO3)6(IDA)21(C2H4NO2)6(C2O4)3(MoO4)(µ2-OH)2(H2O)10]Cl11·32H2O (2) were synthesized by introducing MoO42- anions as templates. Structural analysis indicates that compounds 1 and 2 are isomorphic, featuring a fascinating triangular-shaped metal framework. Magnetic property investigations illuminate the fact that compound 1 exhibits a large -ΔSm of 37.83 J kg-1 K-1 at 3 K for ΔH = 7 T. In particular, it is worth mentioning that compound 1 has an excellent low-field magnetic entropy (-ΔSm = 23.85 J kg-1 K-1 at 2 K, 2 T).

Two bimetal-doped (Fe/Co, Mn) polyoxometalate-based hybrid compounds for visible-light-driven CO2 reduction.

Two polyoxometalate (POM)-based hybrid compounds have been successfully designed and constructed by the hydrothermal method with molecular formulas [K(H2O)2FeII0.33Co0.67(H2O)2(DAPSC)]2{[FeII0.33Co0.67(H2O)(DAPSC)]2[FeII0.33Co0.67(H2O)4]2[Na2FeIII4P4W32O120]}·21.5H2O (1), and [Na(H2O)2FeII0.33Mn0.67(H2O)2(DAPSC)]2{[FeII0.33Mn0.67(H2O)(DAPSC)]2[FeII0.33Mn0.67(H2O)4]2[Na2FeIII4P4W32O120(H2O)2]}·24H2O (2) (DAPSC = 2,6-diacetylpyridine bis-(semicarbazone)), respectively. Structural analysis revealed that 1 and 2 consisted of metal-organic complexes containing DAPSC ligands with dumbbell-type inorganic clusters, iron-cobalt (iron-manganese) and some other ions. By utilizing a combination of strongly reducing {P2W12} units and bimetal-doped centres the CO2 photoreduction catalytic capacity of 1 and 2 was improved. Notably, the photocatalytic performance of 1 was much better than that of 2. In CO2 photoreduction, 1 exhibited CO selectivity as high as 90.8%. Furthermore, for 1, the CO generation rate reached 6885.1 µmol g-1 h-1 at 8 h with 3 mg, and its better photocatalytic performance was presumably due to the introduction of cobalt and iron elements to give 1 a more appropriate energy band structure. Further recycling experiments indicated that 1 was a highly efficient CO2 photoreduction catalyst, which could still possess catalytic activity after several cycles.

Layered Co-O Cluster Applied to Photocatalytic CO2 Reduction.

In the field of recycling CO2, the photocatalytic CO2 reduction reaction (CO2RR) is a typical example, and researchers have designed a variety of photocatalysts to improve the conversion rate of CO2 over the years. In this paper, two metal-oxygen clusters are designed and formulated as [Co3Zn(OH)6(SO4)]·4H2O (1) and [Ni3Zn(OH)6(SO4)]·4H2O (2). As for compound 1, the main structure is composed of {CoO6} octahedra connected by edge-sharing to form a two-dimensional layer, on which {ZnO4} and {SO4} tetrahedra are supported. More interestingly, compound 1 has outstanding photocatalytic activity, which is mainly attributed to the open-framework structure and the cobalt ions as active sites. Upon catalysis for eight hours, its maximum CO generation rate is 9982.13 µmol g-1 h-1, with a selectivity of 81.8%. Additionally, compound 1 takes on weak antiferromagnetic coupling due to Co(II) ions.

A turn-on fluorescent strategy for alkaline phosphatase detection based on enzyme-assisted signal amplification.

As a representative biochemical indicator, alkaline phosphatase (ALP) is of great importance in indicating and diagnosing clinical diseases. Herein, we developed a signal-on fluorescence sensing method for sensitive ALP activity detection based on the enzyme-assisted target recycling (EATR) technique. In this method, a two-step signal amplification process is designed. In the presence of ALP, the 3' phosphate group of an ss-DNA is removed explicitly by ALP, thus releasing free 3'-OH. Terminal deoxynucleotidyl transferase (TdT) can subsequently extend this substrate to generate poly(A) tails, converting the trace-level ALP information into multiple sequences and achieving the first-time amplification. A poly(T) Taqman probe labeled with FAM and BHQ1 provides the second one under the assistance of T7 exonuclease (T7 Exo) through alternate hybridization and degradation of ds-DNA regions. The previously quenched fluorescence is recovered due to the departure of FAM/BHQ1 during the cleavage of T7 Exo. Thus, taking advantage of template-free TdT-mediated polymerization and T7 Exo-based EATR, this strategy shows a sensitive LOD at 0.0074 U/L (S/N = 3) and a linear range of 0.01-8 U/L between ALP concentration and fluorescence intensity. To further verify the specificity and accuracy in practical application, we challenged it in a set of co-existing interference and biological environments and have gained satisfying results. The proposed method successfully quantified the ALP levels in clinical human serum samples, suggesting its applicability in practical application. Moreover, we have used this method to investigate the inhibition effects of Na3VO4. Above all, the proposed assay is sensitive, facile, and cost-effective for ALP determining, holding a promising perspective and excellent potential in clinical diagnosis and drug screening.

A fluorescence strategy for the rapid detection of miRNA-21 based on G-quadruplex and cyclic amplification signal.

MicroRNAs (miRNAs) are commonly used as biomarkers for the diagnosis of tumors. Since miRNA expression is strongly correlated to carcinogenesis, the detection of miRNA concentration in cells would be valuable for the diagnosis and evaluation of tumors. In this study, we proposed a system using two strands of DNA, one modified by a phosphate group at the 5' end, called Cap, and the other with a hairpin structure, called HP. The Cap chain could open the hairpin structure of HP and expose the sequences rich in G bases to form the G-quadruplex structure. Then, a strong fluorescence signal was emitted in the presence of N-methyl mesoporphyrin IX (NMM). However, with the addition of miRNA-21, Cap hybridized with it to form double chains, which were then cleaved by the digestion of lambda exonuclease, resulting in a weak fluorescent signal. The proposed method could detect miRNA-21 at a concentration of 1.4 pM with a broad dynamic linear range from 5 pM to 5 nM.

A fluorescent assay for alkaline phosphatase activity based on phosphorylation protection and DNAzyme-assisted amplification.

Alkaline phosphatase is one of the most important tool enzymes and diseases indicator, monitoring ALP activity with convenient, precise, efficient and sensitive methods plays a fundamental role in modern life and healthcare industries. In this study, we described a novel method for ALP analysis based on Pb2+ dependent DNAzyme. By modifying DNAzyme sequence with terminal phosphate group and introducing exonuclease I (exo I), we managed to analyze ALP by utilizing its causal function of DNAzyme probe from exo I mediated degradation and function of triggering the subsequent cleavage of the hairpin reporting probe. Other than one amplificative strategy by DNAzyme mediated cleavage and cycle, this system also involved an exo I mediated degradation to further reduce the background noise. Combining stepwise fluorimetry and electrophoresis, we verified the detective mechanism of this proposed method. Further, after selectivity demonstration, this method achieved a considerable LOD of 0.0017 U L-1 and linear range of 0.0025 U L-1 to 250 U L-1. For potential of practical application, this method also exhibited excellent performances in inhibitor screening and intracellular ALP assay, both with a linear fitting equation. Based on these results, this method should be highly committed for improving ALP analysis in modern life industry.

A novel biomimetic nanomedicine system with anti-inflammatory and anti-osteoporosis effects improves the therapy efficacy of steroid-resistant nephrotic syndrome.

Clinically, steroid-resistant nephrotic syndrome (SRNS) is always prolonged and difficult to treat and easily develops into end-stage renal disease, resulting in a low survival rate. Strategies to reverse steroid resistance and reduce the long-term use of high doses of steroid medicines are urgently needed. In this study, a novel nanoparticle drug system (Pm-GCH) with a core-shell structure was designed. Metal-organic frameworks, synthesized by glycyrrhizic acid (G) and calcium ions (Ca2+) loaded with hydrocortisone (H) were the core of the nanoparticles. Platelet membrane vesicles were the shells. The natural platelet membrane endows Pm-GCH with good biocompatibility and the ability to promote immune escape. In addition, under the chemotaxis of inflammatory factors, platelet membranes assist Pm-GCH in nonspecific targeting of the inflammatory sites of the kidney. Under an inflammatory acid environment, GCH slowly degrades and releases glycyrrhizic acid and hydrocortisone. Glycyrrhizic acid inhibits the inactivation of hydrocortisone, jointly inhibits the activity of phospholipase A2 (PLA2) and the classic activation pathway of complement C2, blocks the production of inflammatory factors, plays an anti-inflammatory role, and enhances the efficacy of hydrocortisone in the treatment of SRNS. Moreover, glycyrrhizic acid alleviates osteoporosis induced by long-term use of glucocorticoids. These results indicate that Pm-GCH is a promising treatment strategy for SRNS.

Aptamer-Based Fluorometric Ochratoxin A Assay Based on Photoinduced Electron Transfer.

This study describes a novel quencher-free fluorescent method for ochratoxin A (OTA) detection based on the photoinduced electron transfer (PIET) between guanine and fluorophore. In the absence of OTA, carboxyfluorescein (FAM)-labeled aptamer can partly hybridize with the complementary strand of OTA aptamer (OTA-cAPT), which contains four guanines at its 3'-end. As a result, the fluorescence of FAM is quenched due to PIET and stacked guanines. In the presence of OTA, FAM-labeled OTA aptamer can bind specifically to OTA, and thereby the high fluorescence intensity of the dye can be maintained. Under the optimal conditions, the method had a detection limit of 1.3 nM. In addition, the method we proposed is highly sensitive and specific for OTA. Furthermore, the method was proven to be reliable based on its successful application in the detection of OTA in red wine samples. Therefore, this promising, facile, and quencher-free method may be applied to detect other toxins by using other appropriate aptamers.

A Novel Detection Method of Human Serum Albumin Based on the Poly(Thymine)-Templated Copper Nanoparticles.

In this work, we developed a facile fluorescence method for quantitative detection of human serum albumin (HSA) based on the inhibition of poly(thymine) (poly T)-templated copper nanoparticles (CuNPs) in the presence of HSA. Under normal circumstances, poly T-templated CuNPs can display strong fluorescence with excitation/emission peaks at 340/610 nm. However, in the presence of HSA, it will absorb cupric ion, which will prevent the formation of CuNPs. As a result, the fluorescence intensity will become obviously lower in the presence of HSA. The analyte HSA concentration had a proportional linear relationship with the fluorescence intensity of CuNPs. The detection limit for HSA was 8.2 × 10-8 mol·L-1. Furthermore, it was also successfully employed to determine HSA in biological samples. Thus, this method has potential applications in point-of-care medical diagnosis and biomedical research.

Identification and Characterization of Lipopolysaccharide Induced TNFα Factor from Blunt Snout Bream, Megalobrama amblycephala.

Lipopolysaccharide induced TNFα factor (LITAF) is an important transcription factor responsible for regulation of tumor necrosis factor α. In this study, a novel litaf gene (designated as Malitaf) was identified and characterized from blunt snout bream, Megalobrama amblycephala. The full-length cDNA of Malitaf was of 956 bp, encoding a polypeptide of 161 amino acids with high similarity to other known LITAFs. A phylogenetic tree also showed that Malitaf significantly clustered with those of other teleost, indicating that Malitaf was a new member of fish LITAF family. The putative maLITAF protein possessed a highly conserved LITAF domain with two CXXC motifs. The mRNA transcripts of Malitaf were detected in all examined tissues of healthy M. amblycephala, including kidney, head kidney, muscle, liver, spleen, gill, and heart, and with the highest expression in immune organs: spleen and head kidney. The expression level of Malitaf in spleen was rapidly up-regulated and peaked (1.29-fold, p < 0.05) at 2 h after lipopolysaccharide (LPS) stimulation. Followed the stimulation of Malitaf, Matnfα transcriptional level was also transiently induced to a high level (51.74-fold, p < 0.001) at 4 h after LPS stimulation. Taken together, we have identified a putative fish LITAF ortholog, which was a constitutive and inducible immune response gene involved in M. amblycephala innate immunity during the course of a pathogenic infection.

Identification and characterization of a novel Toll-like receptor 4 homologue in blunt snout bream, Megalobrama amblycephala.

Toll-like receptors (TLRs) are central players in the innate immune system in response to a wide range of pathogen infection. Among various TLRs, TLR4 plays a key role in recognition of bacterial lipopolysaccharides (LPS). In the present study, we identified and characterized a novel TLR4 homologue (maTLR4b) in blunt snout bream (Megalobrama amblycephala) which was significantly distinct from previously reported M. amblycephala TLR4 (tentatively named maTLR4a). The results showed that the complete cDNA sequence of maTLR4b was 3261 bp with an open reading frame encoding a polypeptide of 820 amino acids, and that its genomic sequence was 3793 bp, which had 3 exons. Structurally, the deduced maTLR4b protein showed a typical TLR domain architecture, including a signal peptide, eight leucine-rich repeats (LRRs) in the extracellular region, a transmembrane domain, and a Toll-Interleukin 1 receptor (TIR) domain in the cytoplasmic region. Phylogenetic analysis revealed that all TLR4s from teleost fish formed a monophyletic clade. Both maTLR4a and maTLR4b were divided into two distinct branches, and showed the highest level of similarity with the grass carp TLR4.2 and TLR4.4 homologue, respectively. MaTLR4b was constitutively expressed in all healthy tissues tested although at different levels. After LPS stimulation, the expression levels were significantly up-regulated in spleen, and peaked at 4 h between maTLR4a and maTLR4b, but with a distinct and complementary expression patterns. Taken together, these results suggested that maTLR4b is indeed a functional homologue of TLR4 in other species, which may play vital role in innate immune.

New ZNF644 mutations identified in patients with high myopia.

PURPOSE: Myopia, or near-sightedness, is one of the most common human visual impairments worldwide, and high myopia is one of the leading causes of blindness. In this study, we investigated the mutation spectrum of ZNF644, a causative gene for autosomal dominant high myopia, in a high-myopia cohort from a Chinese population. METHODS: DNA was isolated with the standard proteinase K digestion and phenol-chloroform method from a case cohort of 186 subjects diagnosed with high myopia (spherical refractive error equal or less than -6.00 diopters). Sanger sequencing was performed to find potential mutations in all coding exons, flanking splicing sites, and untranslated regions (UTRs) of ZNF644 (NM_201269). Identified novel variants were further screened in 526 ethnically matched normal controls. Functional prediction and conservation analysis were performed using ANNOVAR. RESULTS: Five novel variants were identified. Three are missense (c.1201A>G:p.T401A, c.2867C>G:p.T956S, c.3833A>G:p.E1278G), one is synonymous (c.2565A>G:p.T855T), and one (c.-219C>A) is located in the 5' UTR. Functional prediction indicates that c.3833A>G:p.E1278G was predicted to be damaging by SIFT and Polyphen2. Conservation analysis using PhyloP and GERP++ indicate all of the missense variants are highly conserved. None of these novel mutations was identified in 526 normal controls. CONCLUSIONS: ZNF644 is associated with high myopia in a cohort from a Chinese population. ZNF644 mutations have a minor contribution to the genetic etiology of high myopia.

Disruption of Contactin 4 in two subjects with autism in Chinese population.

Autism is a heterogeneous childhood neurodevelopmental disorder that is characterised by deficits in verbal communication, impaired social interactions, restricted interests and repetitive behaviours. Using an Illumina HumanCNV370-Quad BeadChip, we identified two Han Chinese individuals with autism and large duplications (~1.6 Mb and ~2.4 Mb) disrupting the same CNTN4 gene. CNTN4 encodes a protein that functions as a cell-adhesion molecule and may play an essential role in the formation of axon connections in the developing nervous system. The disruption of this gene has been reported to be the cause of the 3p deletion syndrome and also a possible susceptibility factor for autism spectrum disorders (ASDs). Our results suggest that rare copy number variations (CNVs) in CNTN4 may also influence autism susceptibility in Asian populations. Interestingly, a comparison of the clinical phenotypes between the two subjects revealed that the subject with the 2.4 Mb CNV (involving several other genes) presented with a more severe phenotype than the subject with the 1.6 Mb CNV (disrupting only CNTN4 and CNTN6). This suggests that other genes in the nearby region may contribute to the pathogenesis.

A novel locus for congenital simple microphthalmia family mapping to 17p12-q12.

PURPOSE: To investigate the etiology in a family with autosomal-dominant congenital simple microphthalmia of Chinese origin. METHODS: A whole-genome scan was performed by using 382 microsatellite DNA markers after the exclusion of reported candidates linked to microphthalmia. Additional fluorescent markers were genotyped for fine mapping. To find out the novel predisposing gene, 14 candidate genes including CRYBA1 and NCOR1 were selected to screen for the mutation by the PCR direct-sequencing method. Genome-wide single-nucleotide polymorphism (SNP) genotyping was performed to find out the pathogenetic copy number variation, as well. RESULTS: The most statistically significant linkage results were obtained at D17S1824 (maximum LOD score, 4.97, at recombination fraction 0.00). Haplotype analyses supported the location of the disease-causing gene to a 21.57-cM interval between loci D17S900 and D17S1872 of chromosome 17, region p12-q12. However, no mutation or CNV (copy number variation) was identified to be responsible for the microphthalmia phenotype of this pedigree. CONCLUSIONS: A novel suggestive linkage locus for congenital microphthalmia was detected in a Chinese family. This linkage region provides a target for susceptibility gene identification.

[GPI-PLD gene exon14 polymorphisms of leucocyte in peripheral blood from healthy persons and leukemia patients].

OBJECTIVE: To analyze the polymorphisms of glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) gene exon 14, GPI-PLD activity of leucocyte in the peripheral blood,and the relationship in leukemia patients of Han nationality in Hunan. METHODS: Both 96 leukemia patients and 96 healthy persons of Han nationality in Hunan were researched [including 48 acute non-lymphocytic leukaemia (ANLL) patients as group A, 31 acute lymphoblastic leukaemia (ALL) patients as group B, 12 chronic granulocytic leukaemia (CML) patients as group C, 5 chronic lymphocytic leukaemia (CLL) patients as group D]. The polymorphisms were analyzed by PCR-SSCP and sequencing;. and GPI-PLD activities were determined by GPI-anchored placental alkaline phosphatase (PLAP) as substrate and triton-X114 partioning. RESULTS: There were four variations in the coverage of GPI-PLD gene exon 14 of leukemia patients and healthy persons. The codons of variation were: 1257 C-->T, 1298 T-->C, 1218 C-->A, 1257 C-->A. The total various frequency in leukemia patient and healthy person, which was determined by SSCP, was 28.12% and 20.83%. On the basis of the percentage of GPI-anchored PLAP conversion, the leucocyte GPI-PLD activities of the 96 leukemia patients were measured. Compared with the 96 healthy controls, the leukocyte GPI-PLD activites of ANLL and CLL patients were significantly increased; the acticities of ALL and CML patients were significantly reduced. CONCLUSION: Leukocyte GPI-PLD gene in the peripheral blood, which belongs to healthy persons and leukemia patients of Han nationality in Hunan, is polymorphism. The leukocyte GPI-PLD activities in the four groups are remarkable.

[Effect of the expression of glycosylphosphatidylinositol-specific phospholipase D gene on K562 cell sensitivity to complement killing].

OBJECTIVE: To detect the release of glycosylphosphatidylinositol (GPI) anchored CD55 and CD59, and the effect of complement dependent cytotoxicity on K562 cell with expression of GPI-PLD by glucose or insulin. METHODS: CD55 and CD59 were detected by Western blotting; GPI-PLD activities were analyzed quantitatively; and complement dependent cytotoxicity (CDC) effects were observed by staining of trypan blue. RESULTS: After being induced by insulin or glucose for 24 h and 48 h, GPI-PLD activities and rate of CDC killing in the insulin, insulin + glucose groups significantly increased. At 24 h after the inducement, CD55 was found in the membrane proteins in the control, glucose and insulin groups and CD59 in membrane proteins in the control, glucose group, and medium supernatants of insulin, glucose + insulin groups. Both CD55 and CD59 were found in membrane proteins in control group, and medium supernatants of glucose, insulin, glucose + insulin group at 48 h after the inducement. CONCLUSION: Treatment with insulin resulted in the obvious increase of GPI-PLD activity in K562 cell, which led to releasing of GPI anchored CD55 and CD59 into medium, and increased sensitivity of these cells to CDC killing.