First-principles theoretical study on dry reforming of methane over perfect and boron-vacancy-containing h-BN sheet-supported Ni catalysts.

The entire reaction mechanism of the dry reforming of methane (DRM) as well as the competition processes over perfect and boron-vacancy-containing h-BN sheet-supported Ni-catalysts (labeled Ni2/h-BN and Ni2/h-BN-B-D) was studied by density functional theory calculations in the present work. Our calculation results show that B-defected h-BN strongly binds to the Ni2 active sites (i.e., shows a strong metal-support interaction (SMSI) character) due to the better electron transfer between Ni2 sites and the support. It was found that CH4 is easier to activate than molecular CO2. The activation of CO2 occurs on the surface of Ni2/h-BN through a direct route, whereas it is prone to follow a hydrogen-assisted path for Ni2/h-BN-B-D via the COOH* intermediate, and the results show that the oxidant O* is easily formed on the surface of Ni2/h-BN-B-D. It was also found that O* is the main oxidant agent for CHx* intermediates through the CH3-O oxidation mechanism. The reaction kinetic analysis indicated that the reverse water gas shift reaction (RWGS) is much more favorable than DRM (1.30 vs. 1.72 eV) over the Ni2/h-BN system, whereas the RWGS and DRM are comparable on Ni2/h-BN-B-D (1.77 vs. 1.66 eV), suggesting a high DRM activity on Ni2/h-BN-B-D. Moreover, neither methane cracking nor a Boudouard reaction to form C* species is thermodynamically and kinetically unfavorable over Ni2/h-BN-B-D; hence, Ni2/h-BN-B-D has strong resistance to carbon deposition. Compared to Ni(111), both Ni2/h-BN-B-D and Ni2/h-BN show strong resistance to carbon deposition. Our results provide a further mechanistic understanding of the DRM over an Ni-based catalyst through the SMSI characteristic and the SMSI favors strong resistance to carbon deposition.

A new epoxy-cadinane sesquiterpene from the marine brown alga Dictyopteris divaricata.

A new epoxy-cadinane sesquiterpene, 4beta,5beta-epoxycadinan-1beta-ol (1), and six known cadinane sesquiterpenes: cadinan-1,4,5-triol (2), 4alpha,5beta-dihydroxycubenol (3), cubenol (4), cadinan-3-ene-1,5-diol (5), cubenol-3-one (6), and torreyol (7), were isolated from a sample of marine brown alga Dictyopteris divaricata collected off the coast of Yantai (China). Their structures were established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.

Novel self-adaptive boat-shaped complexes with a tetraphosphine ligand.

A series of novel boat-shaped host-guest complexes were designed and synthesized by the combination of a new calixarene fragment-based tetraphosphine ligand L with group 11 metal salts Cu(MeCN)4ClO4 and AgNO3 in a self-assembly process, and by the following anion exchange reactions of complex 1 with sodium p-toluenesulfonate, AcONa, PhCO2Na and sodium 9-anthrylcarboxylate. The host with a novel boat-shaped cavity is capable of self-adaptive encapsulation of various anions of different sizes through M(i)-O coordinations and CHπ interactions between the host and guest anion. The DFT calculations confirmed that the CHπ interaction played a vital role in the self-adaptive phenomenon in complexes 4-6.

An Overexpressed Q Allele Leads to Increased Spike Density and Improved Processing Quality in Common Wheat (Triticum aestivum).

Spike density and processing quality are important traits in modern wheat production and are controlled by multiple gene loci. The associated genes have been intensively studied and new discoveries have been constantly reported during the past few decades. However, no gene playing a significant role in the development of these two traits has been identified. In the current study, a common wheat mutant with extremely compact spikes and good processing quality was isolated and characterized. A new allele (Qc1 ) of the Q gene (an important domestication gene) responsible for the mutant phenotype was cloned, and the molecular mechanism for the mutant phenotype was studied. Results revealed that Qc1 originated from a point mutation that interferes with the miRNA172-directed cleavage of Q transcripts, leading to its overexpression. It also reduces the longitudinal cell size of rachises, resulting in an increased spike density. Furthermore, Qc1 increases the number of vascular bundles, which suggests a higher efficiency in the transportation of assimilates in the spikes of the mutant than that of wild type. This accounts for the improved processing quality. The effects of Qc1 on spike density and wheat processing quality were confirmed by analyzing nine common wheat mutants possessing four different Qc alleles. These results deepen our understanding of the key roles of Q gene, and provide new insights for the potential application of Qc alleles in wheat quality breeding.

Mechanisms of wheat (Triticum aestivum) grain storage proteins in response to nitrogen application and its impacts on processing quality.

Basis for the effects of nitrogen (N) on wheat grain storage proteins (GSPs) and on the establishment of processing quality are far from clear. The response of GSPs and processing quality parameters to four N levels of four common wheat cultivars were investigated at two sites over two growing seasons. Except gluten index (GI), processing quality parameters as well as GSPs quantities were remarkably improved by increasing N level. N level explained 4.2~59.2% and 10.4~80.0% variability in GSPs fractions and processing quality parameters, respectively. The amount of N remobilized from vegetative organs except spike was significantly increased when enhancing N application. GSPs fractions and processing quality parameters except GI were only highly and positively correlated with the amount of N remobilized from stem with sheath. N reassimilation in grain was remarkably strengthened by the elevated activity and expression level of glutamine synthetase. Transcriptome analysis showed the molecular mechanism of seeds in response to N levels during 10~35 days post anthesis. Collectively, we provided comprehensive understanding of N-responding mechanisms with respect to wheat processing quality from N source to GSPs biosynthesis at the agronomic, physiological and molecular levels, and screened candidate genes for quality breeding.

Linoleic acid isomerase gene FgLAI12 affects sensitivity to salicylic acid, mycelial growth and virulence of Fusarium graminearum.

Fusarium graminearum is the major causal agent of fusarium head blight in wheat, a serious disease worldwide. Linoleic acid isomerase (LAI) catalyses the transformation of linoleic acid (LA) to conjugated linoleic acid (CLA), which is beneficial for human health. We characterised a cis-12 LAI gene of F. graminearum (FGSG_02668; FgLAI12), which was downregulated by salicylic acid (SA), a plant defence hormone. Disruption of FgLAI12 in F. graminearum resulted in decreased accumulation of cis-9,trans-11 CLA, enhanced sensitivity to SA, and increased accumulation of LA and SA in wheat spikes during infection. In addition, mycelial growth, accumulation of deoxynivalenol, and pathogenicity in wheat spikes were reduced. Re-introduction of a functional FgLAI12 gene into ΔFgLAI12 recovered the wild-type phenotype. Fluorescent microscopic analysis showed that FgLAI12 protein was usually expressed in the septa zone of conidia and the vacuole of hyphae, but was expressed in the cell membrane of hyphae in response to exogenous LA, which may be an element of LA metabolism during infection by F. graminearum. The cis-12 LAI enzyme encoded by FgLAI12 is critical for fungal response to SA, mycelial growth and virulence in wheat. The gene FgLAI12 is potentially valuable for biotechnological synthesis of cis-9,trans-11 CLA.

Monitoring disease progression and treatment efficacy with circulating tumor cells in esophageal squamous cell carcinoma: A case report.

This study investigated whether changes in circulating tumor cell (CTC) numbers reflect tumor progression and treatment efficacy in esophageal squamous cell carcinoma (ESCC). A 47-year-old male patient with ESCC is presented in this case study. The patient was evaluated for a series of serum tumor markers and subjected to radiological examinations before and after surgery and during follow-up over the course of five years. In addition, the CTCs in 7.5 mL of peripheral blood were enriched by magnetic-activated cell sorting negative selection and identified by immunofluorescence staining. Serum tumor markers remained within normal ranges and were discordant with imaging scans during the follow-up. Initially, one CTC was detected in the peripheral blood sample, and 14 were observed seven days after the operation. After 12 wk, subcutaneous metastases and bone metastases occurred, and the number of CTCs increased to 84. After 48 wk, lung metastases were noted, and the CTC level was 21. At 104 wk, the number of CTCs was 14, and disease recurrence was detected by positron emission tomography-computed tomography. The CTC counts were in accord with the imaging studies at several time points. The additional information provided by CTC enumeration could thus facilitate monitoring of disease status and treatment efficacy and provide support for treatment decisions.

Effect of Yifei Huoxue Granule on the proliferation of rat pulmonary artery smooth muscle cells upon exposure to chronic hypoxic conditions in vitro.

OBJECTIVE: To investigate the inhibitory effect of Yifei Huoxue Granule (, YFHXG) on the hypoxia-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs) and its mechanism of decreasing pulmonary arterial pressure. METHODS: Twenty male Sprague-Dawley (SD) rats were randomly divided into four groups: saline, and 0.66, 3.30 and 16.50 g/kg of YFHXG groups, the saline and different concentrations of YFHXG were given twice daily for 7 days, respectively. Serum-pharmacology method was used in the preparation of YFHXG serum. Tissue block anchorage was employed in the primary culture of rat PASMCs. The PASMCs were randomly divided into normoxia group, hypoxia group, and hypoxia+YFHXG group (0.66, 3.30 and 16.50 g/kg doses of YFHXG-treated serum groups, exposed to hypoxic condition). PASMCs in normoxia and hypoxia group were cultured with saline serum, hypoxia+YFHXG groups were cultured with different concentrations of YFHXG serum. Cell viability was assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle was analyzed using flow cytometry. In addition, hypoxia inducible factor-1-alpha (HIF-1α) protein expression was evaluated by immunocytochemistry analysis, the concentration of intracellular reactive oxygen species (ROS) and Ca(2+) were determined by laser scanning confocal microscopy (LSCM). RESULTS: MTT assay and flow cytometry showed that hypoxia could directly activate the proliferation of PASMCs, while YFHXG dose-dependently inhibited hypoxia-induced proliferation of rat PASMCs. Immunocytochemistry showed that hypoxia enhanced HIF-1α protein expression, and LSCM showed that hypoxia significantly increased intracellular ROS and Ca(2+), while YFHXG decreased the expression of HIF- 1α and attenuated the hypoxia-induced increase in intracellular concentration of ROS and Ca(2+). CONCLUSIONS: YFHXG could inhibit hypoxia-induced proliferation of rat PASMCs, which may decrease pulmonary arterial pressure and vascular remodeling. The anti-hypoxia effect of YFHXG may be explained by its regulation of HIF-1α expression and of the levels of intracellular ROS and Ca(2+).

[Preparation and characterization of monoclonal antibody against Vibrio vulnificus].

AIM: To prepare high-performance and specific monoclonal antibody (mAb) against Vibrio vulnificus and carry out characterization. METHODS: BALB/c mice were immunized with Vibrio vulnificus protein, and hybridoma cells against Vibrio vulnificus were produced by cellsion technique. The titers of mAbs against vvhA and cross-reaction between the anti-vvhA mAb and other other important marine bacteria were screened by ELISA and Western blot. RESULTS: Five strains of hybridoma were obtained. Identification result indicated that 5 mAbs have favourable specifity and immunoreactivity. CONCLUSION: Specific mAbs against Vibrio vulnificus were produced which provides an important preparation for establishing rapid-detection kit of detecting Vibrio vulnificus.

[Cloning of human scFv against soman transition state analogues (P6) from a large phage antibody library].

AIM: To clone human anti-soman transition state analogues antibodies from a large single-chain phage antibody library. METHODS: An organophosphorus hapten P6 [O1-methyl-O2-(1, 2, 2-trimethylpropyl)-2-hydroxy-5-nitrophenyl methylphosphonic acid] was synthesized. Its chemical conjugate with bovine serum albumin (BSA) was used as antigen (P6-BSA) to screen antibodies against soman. Panning of a large single-chain phage antibody library was conducted to select specific antibodies against soman. The antigen binding characteristics were analyzed by ELISA. RESULTS: After 4 rounds of panning, 14 clones had specific binding ability to P6. DNA fingerprinting showed that diverse specific human scFvs against P6 was obtained from the library by biopanning. CONCLUSION: Human anti-soman transition state analogues scFvs have been cloned from large phage antibody library.

[Screening of human anti-TNF-alpha scFv from large phage library].

AIM: To clone human anti-TNF-alpha scFv from large phage antibody library. METHODS: Panning of large phage library against TNF-alpha was conducted to select specific antibodies. The antigen binding activity and DNA sequence were determined and analyzed by ELISA, restriction enzyme map. RESULTS: After 4 rounds of panning, 62 positive clones were obtained and 27 clones had specific binding ability to TNF-alpha. DNA fingerprinting of the 27 clones showed 7 different stripes indicated 7 different positive clones. 5 of the 7 clones expressed soluble anti-TNF-alpha activity. DNA sequence analysis showed that the variable regions of these scFvs belonged to different subgroups. CONCLUSION: Human TNF-alpha scFv have been successfully obtained from large phage antibody library.

Rapid detection of hepatitis B virus surface antigen by an agglutination assay mediated by a bispecific diabody against both human erythrocytes and hepatitis B virus surface antigen.

Bispecific antibodies have immense potential for use in clinical applications. In the present study, a bispecific diabody against human red blood cells (RBCs) and hepatitis B virus surface antigen (HBsAg) was used to detect HBsAg in blood specimens. The bispecific diabody was constructed by crossing over the variable region of the heavy chains and the light chains of anti-RBC and anti-HBsAg antibodies with a short linker, SRGGGS. In enzyme-linked immunosorbent assays, this bispecific diabody showed specific binding to both RBCs and HBsAg. When this bispecific diabody was mixed with human blood specimens in the presence of HBsAg, the dual binding sites of the diabody caused agglutination of human RBCs. This diabody-mediated agglutination assay was then used to test 712 clinical blood specimens and showed 97.7% sensitivity and 100% specificity when the results were compared with those of the conventional immunoassay, which was used as a reference. This autologous RBC agglutination assay provides a simple approach for rapid screening for HBsAg in blood specimens.

[Preparation of humanized anti-digoxin scFv and diabody].

AIM: To prepare humanized anti-digoxin(Dig) antibodies(single chain Fv, scFv) from a human phage antibody library and construct anti-Dig diabody vector. METHODS: A human phage antibody library was panned against immobilized Dig for four times, and the specificity of the selected scFv expression clones was identified by ELISA. Positive clones against Dig were analyzed by DNA fingerprint and sequencing. A clone which had high affinity to Dig was selected to construct a diabody vector. Diabody was secreted from E. coli by IPTG induction, and the specificity was also identified by ELISA. RESULTS: After four rounds of panning, four specific humanized anti-Dig antibodies(scFv) were obtained. DNA fingerprint and sequencing analysis proved that they had different Ab-encoding genes. The V(L) of the 4 expression clones belonged to lambda subgroup 1 and V(H) belonged to 3 and 4 subgroups, respectively. A scFv clone was picked out to construct diabody vector. The prepared humanized diabody reacted with Dig specifically. CONCLUSION: Humanized anti-Dig antibodies(scFv) have been got by using phage display. A diabody has been obtained from scFv. These humanized anti-Dig antibodies may be used for the diagnosis and therapy of Dig toxication.

[Screening of human scFv against IL-8 from phage antibody library].

AIM: To screen human scFv against IL-8 from phage antibody library. METHODS: IL-8-His fusion protein was expressed in E.coli BL21 (DE3) transfected with prokaryotic expression vector pRSET-IL-8 and was purified by affinity chromatography. Specific antibody was screened by 3 rounds of panning of phage antibody library with the fusion protein. The antigen binding activity and DNA sequences of positive clones were determined and analyzed. RESULTS: After 3 rounds of panning, 2 positive clones were obtained which could bind IL-8 specifically. DNA sequence analysis showed both of the 2 VH genes belonged to human IgG VH3 subgroup, and the Vlambda gene belonged to human VlambdaDPL5 and VlambdaDPL2 subgroups,respectively. CONCLUSION: It is feasible to obtain human anti-IL-8 antibody by phage display technique, which provides the basis for further research on psoriasis and other related diseases.