Recent advances in enzymatic and chemoenzymatic synthesis of N- and O-glycans.

Glycosylation is one of the most common post-translational modifications of proteins, which plays essential roles in regulating the biological functions of proteins. Efficient and versatile methods for the synthesis of homogeneous and well-defined N- and O-glycans remain an urgent need for biological studies and biomedical applications. Despite their structural complexity, tremendous progress has been made in the synthesis of N- and O-glycans in recent years. This review discusses some recent advances in the enzymatic and chemoenzymatic synthesis of N- and O-glycans.

Synthesis of Anticoagulant Pentasaccharide Fondaparinux via 3,5-Dimethyl-4-(2'-phenylethynylphenyl)phenyl Glycosides.

Here, we disclosed a convenient procedure for the preparation of EPP [3,5-dimethyl-4-(2'-phenylethynylphenyl)phenyl] glycosides and their application to an effective synthesis of fondaparinux, the clinically approved anticoagulant heparin pentasaccharide. The use of EPP glycosides in the one-pot orthogonal glycosylation for the synthesis of heparin-like tetrasaccharides has also been achieved.

Laser Scribing Turns Plastic Waste into a Biosensor via the Restructuration of Nanocarbon Composites for Noninvasive Dopamine Detection.

The development of affordable and compact noninvasive point-of-care (POC) dopamine biosensors for the next generation is currently a major and challenging problem. In this context, a highly sensitive, selective, and low-cost sensing probe is developed by a simple one-step laser-scribing process of plastic waste. A flexible POC device is developed as a prototype and shows a highly specific response to dopamine in the real sample (urine) as low as 100 pmol/L in a broad linear range of 10-10-10-4 mol/L. The 3D topological feature, carrier kinetics, and surface chemistry are found to improve with the formation of high-density metal-embedded graphene-foam composite driven by laser irradiation on the plastic-waste surface. The development of various kinds of flexible and tunable biosensors by plastic waste is now possible thanks to the success of this simple, but effective, laser-scribing technique, which is capable of modifying the matrix's electronic and chemical composition.

Research on the impact of inclusive finance on agricultural green development: Empirical analysis of China's main grain producing areas.

In order to study the impact of inclusive finance on agricultural green development, This paper uses both static panel and dynamic panel (system GMM model) estimation methods to make empirical analysis of the impact of inclusive financial development on agricultural green development. The results both find that there is a significant positive correlation between the level of inclusive financial development, real GDP per capita, the proportion of the added value of agriculture, forestry, animal husbandry and fishery in GDP and agricultural green development. This paper puts forward some countermeasures and suggestions to promote agricultural green development, including vigorously developing inclusive finance, promoting economic growth, promoting the development of agriculture, forestry, animal husbandry and fishery, and increasing environmental protection expenditures.

Facile access to C-glycosyl amino acids and peptides via Ni-catalyzed reductive hydroglycosylation of alkynes.

C-Glycosyl peptides/proteins are metabolically stable mimics of the native glycopeptides/proteins bearing O/N-glycosidic linkages, and are thus of great therapeutical potential. Herein, we disclose a protocol for the syntheses of vinyl C-glycosyl amino acids and peptides, employing a nickel-catalyzed reductive hydroglycosylation reaction of alkyne derivatives of amino acids and peptides with common glycosyl bromides. It accommodates a wide scope of the coupling partners, including complex oligosaccharide and peptide substrates. The resultant vinyl C-glycosyl amino acids and peptides, which bear common O/N-protecting groups, are amenable to further transformations, including elongation of the peptide and saccharide chains.

Reduced Phosphomolybdate Hybrids as Efficient Visible-Light Photocatalysts for Cr(VI) Reduction.

Photocatalytic reduction of hexavalent chromium [Cr(VI)] is a promising technology approach to highly efficiently and environmentally tackle the problem of Cr(VI) pollution, in which the key challenge is in the development of effective photocatalysts. In this work, highly reduced hourglass-type molybdophosphate hybrids with the formulas [Zn(mbpy)(H2O)2]2[Zn(mbpy)(H2O)]2{Zn[P4Mo6O31H7]2}·9H2O (1), [Na(H2O)2]2[Zn(mbpy)(H2O)]2[Zn(mbpy)(H2O)2]2{Zn[P4Mo6O31H6]2}·15H2O (2), and (H2mbpy){[Zn(mbpy)(H2O)]2[Zn(H2O)]2}{Zn[P4Mo6O31H6]2}·10H2O (3) (mbpy = 4,4'-dimethyl-2,2'-bipyridine) have been hydrothermally synthesized and used as photocatalysts for the reduction of Cr(VI) under mild conditions. Structural analysis showed that the inorganic moieties in crystals 1-3 are composed of a unique 0D single cluster form, a 1D chainlike structure, and a 2D-layered structure, respectively, in which polyanions were constructed by hourglass-type molybdophosphates with one Zn(II) ion as the central metal. These hybrids displayed good performance for the photocatalytic reduction of Cr(VI) by virtue of their wide visible-light adsorption, suitable energy band structures, and specific spatial arrangements of polyanionic species. Among them, hybrid 2 exhibits the best photocatalytic performance with a Cr(VI) reduction conversion rate of almost 94.7% within 180 min of reaction time. The photocatalysis mechanism investigation revealed that highly reduced hourglass-type molybdophosphate clusters can be illuminated by visible light. The photoinduced electrons induced by hourglass-type polyanions can directly reduce Cr(VI) to Cr(III), while the photogenerated holes are used to oxidize the sacrificial agent isopropyl alcohol to acetone. This work provides new guidance for the design and preparation of highly efficient photocatalysts for the reduction of Cr(VI).

Synthesis of Forsythenethoside A, a Neuroprotective Macrocyclic Phenylethanoid Glycoside, and NMR Analysis of Conformers.

Forsythenethoside A (1) is a structurally unique macrocyclic phenylethanoid glycoside, which was isolated from Forsynthia suspensa and displayed considerable neuroprotective activities. Here, we report its first chemical synthesis via a longest linear sequence of 14 steps in 5% overall yield wherein intramolecular oxidative coupling was successfully employed to realize the pivotal macrocyclization. NMR analysis revealed the existence of an unexpected conformational interconversion of the congested macrocycles.

The impact of the inclusive financial development index on farmer entrepreneurship.

Based on the calculation of the inclusive financial development level of 22 provinces and 4 municipalities in China from 2004 to 2017, this paper uses the Kernel density estimation method to further analyze the evolution of the inclusive financial index. Based on the above analysis, we make empirical analysis of the impact of China's inclusive financial inclusion development index on farmers' entrepreneurship using static panel and dynamic panel estimation method. The empirical conclusions show that there are certain differences in inclusive financial inclusion development level in various provinces in China. Improving the inclusion development level of inclusive finance can better promote farmers' entrepreneurship. Urbanization level, economic openness and regional economic development level have a significant positive effect on farmers' entrepreneurship, while farmers' income and education level have a significant negative effect on farmers' entrepreneurship. It is possible to promote farmers' entrepreneurship by improving the inclusive development level of inclusive finance, combining urbanization, increasing government investment in productive fixed assets, increasing economic openness and improving regional economic development.

Glycosylation with 3,5-Dimethyl-4-(2'-phenylethynylphenyl)phenyl (EPP) Glycosides via a Dearomative Activation Mechanism.

A highly effective and versatile glycosylation method is developed, which uses 3,5-dimethyl-4-(2'-phenylethynylphenyl)phenyl (EPP) glycosides as donors and NIS/TMSOTf as promoter and proceeds via an unprecedented dearomative activation mechanism.

Comprehensive quantification of N-glycoproteome in Fusarium graminearum reveals intensive glycosylation changes against fungicide.

UNLABELLED: Glycoproteomics is greatly developed in recent years and big data of N-glycoproteome in mammalian tissues and cells were already established. However, the glycoproteomic studies on plant, fungus and bacteria are far left behind. In this study, we comprehensively mapped and quantified the N-glycosylation of Fusarium graminearum by combining stable isotope dimethyl labeling, hydrophilic interaction chromatography (HILIC) and high-resolution mass spectrometry. The N-glycosylation changes in Fusarium graminearum after fungicide treatment were extensively studied. Altogether we identified 927 N-glycopeptides, corresponding to 406 proteins and 774 sites and the glycosylation level was found to be largely down-regulated upon fungicide treatment. With the help of advanced bioinformatics, it was found that the N-glycoproteome changes were highly enriched in cell wall, membrane and extracellular regions. Moreover, the fungal metabolism, protein and glycosylation synthesis, and protease and glycosyl-transferase activity were all closely related with the down-regulated proteins, indicates that fungicide may affect fungal development in these aspects. These results will be useful for future studies on fungal biology. The established system for N-glycoproteome quantification has comparative or better performance compared with previous strategies and will be helpful in N-glycoproteomics of fungus and other species. SIGNIFICANCE: We developed a robust HILIC-based system for N-glycoproteome quantification in fungus and established the largest quantitative N-glycosylation dataset in fungus, showing the high performance of the new system. The identified N-glycoproteins were proved to be high confident due to the high percentage of proteins in extracellular region and plasma. The quantification results were also accuracy and reproducible in two replicates. By the help of advanced bioinformatic tools, the obtained data was systematically analyzed. It was found that the N-glycosylation level was largely changed in cell wall, membrane and extracellular regions. Moreover, the cell metabolism, protein synthesis, and protease activity were also greatly deceased after fungicide treatment.

New analogues of brefeldin A from sediment-derived fungus Penicillium sp. DT-F29.

Four new analogues of brefeldin A named 7, 7-dimethoxybrefeldin C (3), 6ß-hydroxybrefeldin C (4), 4-epi-15-epi-brefeldin A (5), 4-epi-8α-hydroxy-15-epi-brefeldin C (6), together with four known analogues (1, 7-9) were isolated from a fermentation of the sediment-derived fungus Penicillium sp. DT-F29. The structures of these compounds were elucidated on the basis of extensive spectroscopic and chemical methods. In the bioactivity assays, only compounds 1 and 8 showed significant inhibitory activities against human lung adenocarcinoma cell. In addition, compound 1 was first reported for the potent ability to reactivate latent HIV with EC50 value of 0.03 µM.

Interactions in the Competitive Coexistence Process of Streptomyces sp. and Escherichia coli.

Competitive coexistence of different microorganism species is a fundamental ecological process in the evolution and maintenance of biodiversity. This work studied the interactions happened in the competitive coexistence process of actinomycete Streptomyces sp. and Escherichia coli from morphological and secondary metabolites perspective. We found three important interactions occurred in their successful coexistence process: medium pH was elevated, indole alkaloids with dual inhibiting effects were produced, and culture environment was spatially structured. For the weed-like superior competitor E. coli, its massive growth was suppressed by the elevated pH and the newly produced novel bisindole alkaloid hepchrome. For the inferior Streptomyces sp., its mycelium floated to the medium surface for further colonization, and the growth in liquid medium was inhibited by its self-produced alkaloids such as halichrome A, 1,1,1-Tris (3-indolyl) methane, vibrindole A, and hepchrome. The coexistence of E. coli and Streptomyces sp. was thereby achieved through reduction of spatial and energy resource overlapping and suppression of competition.

Production of bioactive tryptamine derivatives by co-culture of marine Streptomyces with Bacillus mycoides.

Tryptamine derivatives such as tryptamine and bacillamides were strong algicidal compounds promising in controlling harmful algae blooms, but their bioactivity and application researches were hindered by extremely low natural production rates. This study found an induced production of algicidal tryptamine derivatives by co-culture of marine Streptomyces with Bacillus mycoides, and optimised the culture method through changing important factors such as medium nutrition content, culture mode and pH value. The final established co-culture method used only 5 g yeast extracts and 5 g glycerol in 1 L 75% sea water, but got a yield of 14.9 mg/L N-acetyltryptamine, 2.8 mg/L N-propanoyltryptamine, 3.0 mg/L bacillamide A, 13.7 mg/L bacillamide B and 9.6 mg/L bacillamide C, which were all undetectable under normal culture conditions.

[Frequency and linkage disequilibrium of specific HLA-DR and HLA-DQ genes in Chinese Han population].

This study was aimed to investigate the distribution feature of HLA-DR/DQ gene linkage disequilibrium in Chinese Han population and to improve the accuracy of HLA matching results. Genotyping of HLA-DR and HLA-DQ gene locus was performed using PCR-SSP typing in Chinese Han population receiving kidney transplantation. The results showed that there were 29 new linkage combinations in 1799 patients, in which DR13-DQ5, DR11-DQ8 and DR8-DQ8 were discovered for 11, 8 and 7 times respectively while DR9-DQ8, DR12-DQ6 and DR14-DQ4 were both discovered for 6 times. The linkage disequilibrium parameters of these haplotypes were negative, showing that these linkages were uncommon. It is concluded that this study not only enriches the classical HLA-DR/DQ linkage combinations, but also indicates the national relevance of combination distribution, and it has great importance in improving the accuracy of HLA matching experiments and reducing unnecessary repeated work.

Impact of filter media on the performance of full-scale recirculating biofilters for treating multi-residential wastewater.

The main objective of this paper was to evaluate the effectiveness of silica sand, crushed glass, peat, and geotextile as a medium in RBFs in the removal for organic matter, nutrients and bacteria from domestic wastewater based on a field-scale study. In particular, this field-scale study was conducted to treat domestic wastewater from a small community of 10 households from the Municipality of Lunenburg, Nova Scotia, Canada. The average influent 5d biochemical oxygen demand (BOD(5)) and total suspended solids (TSS) concentrations into the field filter system were 381+/-64 (mean+/-standard deviation) and 46+/-21 mg/L, respectively. The results showed that crushed glass could be an effective medium in RBFs since the crushed glass filter produced stable effluent BOD(5) and TSS concentrations of less than 20mg/L. Geotextile was found to be another successful alternative filter medium with the effluent BOD(5) and TSS of 18+/-11 and 11+/-7 mg/L, respectively, even though the porosity of geotexitle filter was as high as 0.90. Peat was not able to provide efficient performance due to its poor BOD(5) and NH(4)(+)-N removals. This study measured the water quality variation at different components of the RBFs. The results of this study showed that the recirculation tank was the main facilitator of the denitrification process. In addition, this study found that RBFs could efficiently treat domestic wastewater for BOD(5) removal under the organic loading rates as high as 0.070 kg/m(2)/d.