Search

It is well known that β3-adrenoceptor (β3-AR) in many brain structures including prefrontal cortex (PFC) is involved in stress-related behavioral changes. SR58611A, a brain-penetrant β3-AR subtypes agonist, is revealed to exhibit anxiolytic- and antidepressant-like effects. Whereas activation of β3-AR exerts beneficial effects on cognitive function, the underlying cellular and molecular mechanisms have not been fully determined. In this study, whole cell patch-clamp recordings were employed to investigate the glutamatergic transmission of layer V/VI pyramidal cells in slices of the rat PFC. Our result demonstrated that SR58611A increased AMPA receptor-mediated excitatory postsynaptic currents (AMPAR-EPSCs) through activating pre-synaptic β3-AR. SR58611A enhanced the miniature EPSCs (mEPSCs) and reduced paired-pulse ratio (PPR) of AMPAR-EPSCs suggesting that SR58611A augments pre-synaptic glutamate release. SR58611A increased the number of readily releasable vesicle (N) and release probability (Pr) with no effects on the rate of recovery from vesicle depletion. Influx of Ca2+ through L-type Ca2+ channel contributed to SR58611A-mediated enhancement of glutamatergic transmission. We also found that calmodulin, myosin light chain kinase (MLCK) and myosin II were involved in SR58611A-mediated augmentation of glutamate release. Our current data suggest that SR58611A enhances glutamate release by the Ca2+/calmodulin/MLCK/myosin II pathway.

Intrinsically disordered regions (IDRs) are protein sequences lacking fixed or ordered three-dimensional structures. Many IDRs are endowed with important molecular functions such as physical interactions, posttranslational modifications or solubility enhancement. We reveal that several biologically important IDRs can act as N-terminal fusion carriers to promote target protein folding or protein quality control, thereby enhancing protein expression. This nanny function has a reasonably strong correlation with high S/T/Q/N amino acid content in IDRs and it is tunable (e.g., via phosphorylation) to regulate protein homeostasis. We propose a hypothesis that “N-terminal intrinsic disorder facilitates abundance” (NIDFA) to explain how some yeast proteins use their N-terminal IDRs (N-IDRs) to generate high levels of protein product. These N-IDRs are versatile toolkits for functional divergence in signaling and evolution.SignificanceDisorder within an otherwise well-structured protein is mostly found in intrinsically disordered regions (IDRs). IDRs can provide many advantages to proteins, including: (1) mediating protein-protein or protein-peptide interactions by adopting different conformations; (2) facilitating protein regulation via diverse posttranslational modifications; and (3) regulating the half-lives of proteins that have been targeted for proteasomal degradation. Here, we report that several biologically important IDRs inS. cerevisiaecan act as N-terminal fusion carriers to promote target protein folding or protein quality control, thereby enhancing protein expression. We demonstrate by genetic and bioinformatic analyses that this nanny function is well correlated with high content of serine, threonine, glutamine and asparagine in IDRs and is tunable (e.g., via phosphorylation) to regulate protein homeostasis.

TSETA (Third-generation Sequencing to Enable Tetrad Analysis) is a fungus-centric software pipeline that utilizes chromosome-level sequence assembly for genome-wide and single-nucleotide-resolution mapping of single-nucleotide polymorphisms (SNPs), meiotic recombination products, illegitimate mutations (IMs) and repeat-induced point (RIP) mutations. It utilizes a newly invented algorithm (i.e., BLASTN-guided sectional MAFFT) to perform fast, accurate, and low-cost multiple genome sequence alignments. This new algorithm outcompetes next-generation sequencing (NGS)-based variant-calling approaches for accurate and comprehensive identification of single-nucleotide variants (SNVs) and insertion/deletion mutations (Indels) among the near-complete genome sequences of any two or more intraspecific strains, as well as sequences before and after meiosis, with single-nucleotide precision. TSETA also has a powerful tool for the visualization of the results from the scale of the chromosomal landscape to individual nucleotides. The data output files are user-friendly for researchers and students lacking computational expertise to analyze and reason about data and evidence.

Generation of new genetic diversity by crossover (CO) and non-crossover (NCO) is a fundamental process in eukaryotes. Fungi have played critical roles in studying this process because they permit tetrad analysis, which has been used by geneticists for several decades to determine meiotic recombination products. New genetic variations can also be generated in zygotes via illegitimate mutation (IM) and repeat-induced point mutation (RIP). RIP is a genome defense mechanism for preventing harmful expansion of transposable elements or duplicated sequences in filamentous fungi. Although the exact mechanism of RIP is unknown, the C:G to T:A mutations might result from DNA cytosine methylation. A comprehensive approach for understanding the molecular mechanisms underlying these important processes is to perform high-throughput mapping of CO, NCO, RIP and IM in zygotes bearing large numbers of heterozygous variant markers. To this aim, we developed ‘TSETA’, a versatile and user-friendly pipeline that utilizes high-quality and chromosome-level genome sequences involved in a single meiotic event of the industrial workhorse fungus Trichoderma reesei. TSETA not only can be applied to most sexual eukaryotes for genome-wide tetrad analysis, it also outcompetes most currently used methods for calling out single nucleotide polymorphisms between two or more intraspecies strains or isolates.

β-adrenoceptor (β-AR), especially the β1- and β2-AR subtypes, is known to participate in stress-related behavioral changes. Recently, SR58611A, a brain-penetrant β3-AR agonist, exhibits anxiolytic- and antidepressant-like effects. In this study, we sought to study the role of SR58611A in behavioral changes and its potential cellular and molecular mechanism in the prefrontal cortex (PFC). We found that rats with SR58611A (1 mg/kg) enhanced PFC-mediated recognition memory, whereas administration of higher dosage of SR58611A (20 mg/kg) caused hyperlocomotion, and exhibited an impairment effect on recognition memory. Electrophysiological data also indicated that SR58611A (1 mg/kg) selectively enhanced NMDA receptor-mediated excitatory postsynaptic currents (EPSC) through interacting with norepinephrine (NE) system and activating β3-AR, whereas higher dosage of SR58611A (20 mg/kg) reduced both AMPA receptor- and NMDA receptor-mediated EPSC. SR58611A-induced different effects on EPSC linked with the change of the surface expression quantity of NMDA receptor and/or AMPA receptor subunits. Synaptosomal-associated protein 25 (SNAP-25), which is a key soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein involved in incorporation of NMDA receptor to postsynaptic membrane , contributed to SR58611A (1 mg/kg)-induced enhancement of recognition memory and NMDA receptor function. Moreover, SR58611A (1 mg/kg) could rescue repeated stress-induced defect of both recognition memory and NMDA receptor function through a SNAP-25-dependent mechanism. These results provide a potential mechanism underlying the cognitive-enhancing effects of SR58611A (1 mg/kg).

To improve the adhesion and blood-compatibility of the titanium substrate coated with heparin/collagen multilayers, an oxidized dopamine was applied as the interlayer between the multilayers and the substrate. The oxidation condition of the dopamine interlayer was achieved by treating the dopamine solution under an atmospheric environment for 8 h. A dopamine interlayer built in a pure nitrogen environment was used as a benchmark. 4 and 9 multilayers were also built and studied for both samples. The film thickness was evaluated by the cross-sectional technique of focused ion beam microscopy. The hydrophilicity and surface topography of the films were investigated by water contact angle measurement and scanning electron microscopy. The adhesion of the multilayers was studied with scratch tests. The amount of heparin that attached to the samples was measured by toluidine blue O test. The hemocompatibility was verified by the platelet coverage area, activated partial thromboplastin time, and hemolysis ratio in vitro . The results indicated that the oxidized dopamine not only enhanced the uniformity and thickness of heparin/collagen multilayers on a titanium substrate but also promoted the sample's adhesion and hemocompatibility, especially that with a larger number of multilayers.

Vaccines based on melanoma-associated antigens (MAGEs) present a promising strategy for tumor immunotherapy, albeit with weak immunogenicity. In this study, the xenoantigen L-rhamnose (Rha) was chemically conjugated with truncated MAGE-A3 (tMAGE-A3) to generate Rha-tMAGE-A3. The product showed good antigenicity with anti-Rha antibodies purified from human serum. FITC-labeled Rha-tMAGE-A3 was detected in THP-1 human macrophage cells via the anti-Rha antibody-dependent antigen uptake process. Furthermore, peripheral blood mononuclear cells (PBMCs) stimulated with Rha-tMAGE-A3 in the presence of anti-Rha antibodies showed better cytotoxicity toward A375 human melanoma cells surfaced by MAGE-A3 antigen compared to PBMCs stimulated with tMAGE-A3. All data reveal that linking of Rha epitopes to MAGE enhances the immunogenicity of MAGE by harnessing the immune effector functions of human naturally existing anti-Rha antibodies. Rha epitopes could become immunogenicity enhancers of tumor associated antigens in the development of tumor immunotherapies.

Land utilization of sewage sludge has become one of the major issues in environmental mitigation in China. This is particularly important in the Loess Plateau of Northwest China. Sludge enriched with organic matter and nutrients might effectively help to resolve the problems of silty loess soils as evidenced by porosity defect, structural alterations and absence of fertility. After sludge flows into the loess, irrigation water contains heavy metals that leach and migrate into sludge and consequently related human health risks may occur that raise concerns; and this situation needs to be rectified. The characteristics of the vertical migration and composition form change of Cu, Zn, and Cd from composted sludge to loess, and corresponding influencing factors, were investigated by performing a soil column simulation test under the leaching treatment of a one-year irrigation water capacity. Results demonstrated that: (1) composted sludge significantly improved loess fertility, and irrigation leaching transpor...

The proposed hybrid Schottky–ohmic drain structure is analyzed in detail for AlGaN/GaN power high-electron mobility transistors on the Si substrate. Without any additional photomasks and process steps, the hybrid drain design can alter the electric field distribution to improve the breakdown voltage $V_{\rm BK}$ . In addition, it provides an additional current path to achieve zero onset voltage and reduce the ON-resistance. It was found that the Schottky extension $L_{\rm ext}$ is critical to $V_{\rm BK}$ , $R_{{\mathrm{{\scriptstyle ON}}}}$ , and also the current collapse phenomena of the transistors. The extended Schottky electrodes for optimized transistor characteristics are investigated, and the physics behind are discussed. With an $L_{\rm ext}\sim 2$ –3 $\mu $ m, $V_{\rm BK}$ can be improved up to 60% with an $R_{{\mathrm{{\scriptstyle ON}}}}$ degradation below 3%.

To improve yield and quality of lettuce in hydroponic, the growth, quality and activities of enzymes in nitrogen metabolism of lettuce in hydroponics were studied with nanodevices. The results showed that the nitrate reductase activities (NRA) in plants with nanodevices were significantly higher than the control at 16rd day after transplanting (DAT). On the 25th DAT, the shoot fresh weight of lettuce treated with 5.6cm2/L nanodevices was 17.8% higher than the control, while there was no difference in dry weights of shoot among different treatments. The NRA of lettuce increased gradually with the amount of nanodevices increasing from 0 cm2/L to 5.6 cm2/L, then decreased with nanodevices amount increasing. There was no obvious difference in the activities of glutamate dehydrogenase (GDH) and glutamate synthase (GOGAT) among different treatments,while glutamine synthase (GS) activity was enhanced with the increasing of nanodevices amount. On the 34th DAT, the shoot fresh weight of lettuce treated by 5.6cm2/L nanodevices was 11.2% higher than the control. The activities of NR and GS treated by 11.2cm2/L increased 39.7%, 97.7%, respectively compared with CK, while the activities of GDH and GOGAT treated by 5.6cm2/L increased 89.0%, 77.3%, respectively. In treatment with 5.6 cm2/L nanodevices in nutrient solution, the contents of soluble protein, flavonoid, soluble phenolic and ascorbic acid (VC) in lettuce increased 92.8%, 19.8%, 36.7% and 61.5%, respectively.The nitrate content in lettuce significantly increased with the using of nanodevices, but did not exceed the national standard. In conclusion, the yield and quality of hydroponic lettuce were improved by nanodevices, and the activities of enzymes in nitrogen metabolism were enhanced, especially at 25th and 34th DAT and best dosage of nanodevices is 5.6 cm2/L.

Autotoxicity of aqueous extracts from roots, stems and leaves of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) were studied by hydroponic in different concentrations (0.5g/L, 2g/L, 5g/L). The results showed that in solution with aqueous extracts from roots, stems and leaves, the growth of flowering Chinese cabbage were inhibited, leaf chlorophyll content declined, photosynthesis rate were affected, activities of SOD, POD and CAT were changed, MDA concentration increased, thus cell membrane permeability of flowering Chinese cabbage was damaged. The autotoxicity of aqueous extracts in flowering Chinese cabbage increased with the extracts concentration increasing.

Background In the process of ABO-incompatible (ABOi) organ transplantation, removal of anti-A and/or B antibodies from blood plasma is a promising method to overcome hyperacute rejection and allograft loss caused by the immune response between anti-A and/or B antibodies and the A and/or B antigens in the recipient. Although there are commercial columns to do this work, the application is still limited because of the high production cost. Results In this study, the PglB glycosylation pathway from Campylobacter jejuni was exploited to produce glycoprotein conjugated with Escherichia coli O86:B7 O-antigen, which bears the blood group B antigen epitope to absorb blood group B antibody in blood. The titers of blood group B antibody were reduced to a safe level without changing the clotting function of plasma after glycoprotein absorption of B antibodies in the plasma. Conclusions We developed a feasible strategy for the specific adsorption/removal of blood group antibodies. This method will be useful in ABOi organ transplantation and universal blood transfusion. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0538-z) contains supplementary material, which is available to authorized users.

The effect of color shading-nets (red net, blue net and silver net) and ordinary black net on plant growth and nutrient uptake of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) were studied, with no net shading as the control. The results indicated that, compared with the control, red net covering increased plant height, leaf area and stem diameter of flowering Chinese cabbage. Red and blue nets covering enhanced the above ground fresh weight, while the silver and black nets covering decreased the above ground fresh weight. Shading net covering significantly improved the nitrogen (N) and potassium (K) content of flowering Chinese cabbage, while it had no significant effect on the phosphorus (P) content. Red and blue nets covering enhanced mineral nutrients uptake, while it was decreased under silver and black nets covering. Red and blue nets covering promoted plant growth and nutrients uptake of flowering Chinese cabbage and could be widely applied in leaf vegetable production.

Effect of ammonium and nitrate ratio (0:100, 25:75, 50:50 and 75:25) on nutritional quality of Chinese kale (Brassica alboglabra Bailey) with 3 cultivars were studied in hydroponics. The results indicated that, the Vitamin C content in product organ (leaf and stalk) of Chinese kale was decreased by the enhancement of ammonium in nutrient solution, and the decrease was not significant for 25% enhancement of ammonium. 25% ammonium enhancement increased the soluble sugar content in product organ significantly, compared with other treatments. Free amino acids and protein content of Chinese kale increased gradually with the increasing of ammonium proportion in nutrient solution. Integrated nutritional quality of Chinese kale in 25% ammonium enhancement treatment was better than others under hydroponics condition.

Effect of calcium nutrient on calcium distribution and ultrastructure of cell and chloroplast in Bunching Onion (Allium fistulosum L. var. caespitosum Makino) leaf was studied in sands with 4 Ca2+ treatments (0, 40, 80 and 160 mg/L ), in which the solution was Hoagland's. Localization and distribution of calcSuperscript textium and the influence of calcium nutrition on cell ultrastructure were observed by transmission electron microscopy combined with in situ precipitation of calcium with potassium pyroantimonate technique. The results showed that Ca2+ were mainly located in cell membrane, vacuoles, envelope of chloroplast and intercellular space in normal cells of bunching onion, however, Ca2+ was found to compartment in cytosol in large quantity, and the release of membrane-associated Ca2+ to cytosol and wall-associated Ca2+ to the intercellular spaces was observed in Ca-deficient leaves. In serious Ca-deficient leaves, Ca2+ quantities in cell decreased. Under Ca-deficiency, chloroplast membranes, plasma membranes and nuclear membranes were damaged, and cell walls disassociated, an enlarged space could be found between cells. In serious Ca-deficient leaves, cell compartmentation was destroyed, chloroplast deformed, plasma separated from cell wall, then whole cell constricted.

The effect of different ammonium and nitrate ratios (NH4+-N : NO3--N = 0:100, 25:75, 50:50 and 75:25) on growth and yield of Chinese kale (Brassica alboglabra Bailey) with 3 cultivars were studied in hydroponics. The results indicated that, compared with the complete nitrate treatment, plant height, stem diameter and biomass of Chinese kale were increased in the low enhancement of ammonium (25%) in nutrient solution, while plant growth and biomass were decreased in the medium (50%) and high (75%) enhancement of ammonium. Ammonium enhancement treatments increased the root/shoot ratio of Chinese kale. Low enhancement of ammonium (25%) in nutrient solution had no significant effect on root activity of Chinese kale, while it was decreased by the medium (50%) and high (75%) enhancement of ammonium treatments. Nutrient solution with 25% ammonium enhancement maintained a high root absorption capacity and increased plant biomass, so it was appropriate to hydroponics for Chinese kale.

The effect of water stress on growth and quality of bunching onion（Allium fistulosum L. var. caespitosum Makino）was studied in hydroponics by PEG treatments (10%, 15%, 20%). The results showed that the growth of bunching onion was significantly affected by water stress induced by PEG. Plant height, pseudo-stem weight, total plant weight decreased with PEG concentration increased, the inhibitions in 10% PEG and 20% PEG were greater than in 15% PEG. The root/shoot ratio increased in PEG treatments. Concentrations of allicin and pyruvic acid significantly increased at 10, 17 days after PEG treatments. With PEG concentration increased, concentrations of soluble protein increased.

Effect of nitrogen level (50, 100, 200, 300, 400 mg/L) on pigment accumulation of flower stalk in Chinese kale (Brassica alboglabraBailley) (cv. Zhonghua) were studied by hydroponics. The results showed that chlorophyll concentration of flower stalk in 50 mg/L and 100 mg/L N treatments were higher before stage Ⅲ, those in 50 mg/L were the highest, while those in 200 mg/L N treatment were the highest at stage Ⅳ and Ⅴ. Carotenoid concentrations in 50mg/L N treatment were the highest during flower stalk development (except at stageⅤ), while those in 100mg/L N treatment were the highest at stagesⅤ.The concentrations of flavonoids and anthocyanin in flower stalk epidermis were the highest in 100 mg/L N treatment, those in 50mg/L N treatment were higher than other treatments. The ratio of anthocyanin/chlorophyll in flower stalk epidermis also were the highest in 100 mg/L N treatment, and higher in 50mg/L N treatment, thus the epidermis appeared mauve in 50 and 100mg/L N treatments.

Effect of ammonium and nitrate ratios (0:100, 25:75, 50:50 and 75:25) on nutritional quality of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) with 3 cultivars were studied in hydroponics. The results indicated that, with the increasing of ammonium proportion in nutrient solution, the soluble sugar content in product organ of flowering Chinese cabbage increased gradually, but Vc content decreased gradually. Enhancement of ammonium by 25% or 50% in nutrient solution increased the soluble protein content in leaf significantly, while it increased gradually in stalk with the increasing of ammonium proportion. Free amino acids in product organ of flowering Chinese cabbage were improved significantly by enhancement of ammonium in nutrient solution. Integrated nutritional quality of flowering Chinese cabbage in 25% ammonium enhancement treatment was better than others under hydroponics condition.

The continuous enzymatic conversion of D-galactose to D-tagatose with an immobilized thermostable L-arabinose isomerase in packed-bed reactor and a novel method for D-tagatose purification were studied. L-arabinose isomerase from Thermoanaerobacter mathranii (TMAI) was recombinantly overexpressed and immobilized in calcium alginate. The effects of pH and temperature on D-tagatose production reaction catalyzed by free and immobilized TMAI were investigated. The optimal condition for free enzyme was pH 8.0, 60°C, 5 mM MnCl(2). However, that for immobilized enzyme was pH 7.5, 75°C, 5 mM MnCl(2). In addition, the catalytic activity of immobilized enzyme at high temperature and low pH was significantly improved compared with free enzyme. The optimum reaction yield with immobilized TMAI increased by four percentage points to 43.9% compared with that of free TMAI. The highest productivity of 10 g/L h was achieved with the yield of 23.3%. Continuous production was performed at 70°C; after 168 h, the reaction yield was still above 30%. The resultant syrup was then incubated with Saccharomyces cerevisiae L1 cells. The selective degradation of D-galactose was achieved, obtaining D-tagatose with the purity above 95%. The established production and separation methods further potentiate the industrial production of D-tagatose via bioconversion and biopurification processes.

The effects of different NH4+-N to NO3--N ratio (NH4+ /NO3-) (0, 1/8, 1/4 and 1/2) on growth and quality of bunching onion (Allium fistulosum L. var. caespitosum Makino) under high temperature stress (34°C/26°C, day/night) were studied in growth chamber by hydroponics. The results showed that the growth and quality of bunching onion were affected by NH4+ /NO3-. Plant weight and height, leaf number per plant were the highest in the treatment which NH4+ /NO3- was 1/8, and those in treatment without NH4+-N were higher than in other 2 treatments. With the NH4+ /NO3- increasing, nitrate concentration in bunching onion decreased. The concentration of vitamin C was the highest in the treatment which NH4+ /NO3- was 1/8, while concentration of soluble sugar, soluble protein and allicin were the highest in the treatment which NH4+ /NO3-was 1/2. Thus the growth and quality of bunching onion were better in the NH4+ /NO3- range of 1/8 to 1/4.

With uncovered net as a control, the effect of color shading-nets (red net, blue net and silver net) and ordinary black net on growth and physiological characteristics of Chieh-qua (Benincasa hispida Cogn.var. chieh-qua How.) seedling were studied. The result showed that, shading-net covering reduced light intensity and temperature, and increased air humidity of the seedling environment, compared with the control. Shading-net covering increased plant height, stem diameter, leaf area and biomass of Chieh-qua seedling, among which covering of blue and silver shading-nets were superior to the others. Root/shoot ratio and strong seedling index were the biggest under blue net treatment, thus it indicated that blue net covering promoted seedling haleness. Specific leaf weight of Chieh-qua seedling was reduced by covering shading-net. In addition to silver net, leaf chlorophyll and carotenoids content were significantly increased by another 3 covering shading-nets. Relative conductivity (RC), malondialdehyde (MDA) content, superoxidase dismutase (SOD) and peroxydase (POD) activity of Chieh-qua seedling leaf were significantly reduced by shading-net covering. This indicated that shading-net covering in seeding nursery alleviated the stress of intensive light and high temperature, and thus increased the integrated seedling quality. Blue shading-net performed the best among all covering shading-nets.

To increase the adhesion of diamond films and avoid the negative effects of using cobalt, previous treatments have employed tungsten particles to cover the surface of the 6 wt.% cobalt-cemented tungsten carbide (WC-Co) substrate. The surface of the tungsten particles is transformed into W 2 C and WC, which attracts and traps carbon. Through the process of nucleation, the carbon forms around the tungsten particles, thereby satisfying the conditions necessary for the formation of diamond film. Using Raman spectroscopy, we determined that diamond films of good quality with excellent adhesive properties and a hardness level as high as 27.78 GPa could be produced following pretreatment with 2.0 μm tungsten particles. Rockwell indentation tests indicate that addition of tungsten particles promotes the interfacial adhesion of diamond films with WC-Co substrates. We determined that using smaller tungsten particles decreased the number of gaps and cavities on the surface of the substrate, thereby enhancing the adhesion of the diamond film.

GDP-perosamine synthetase (Per, E.C. not yet classified) is important to the synthesis of Escherichia coli O157:H7 O-antigen. The mutant in per gene can disrupt the synthesis of O157 O-antigen. In this study, GDP-perosamine synthetase was cloned from E. coli O157:H7 and over-expressed in E. coli BL21 (DE3). The recombinant His-tagged Per fusion protein was a decamer with molecular weight of 431 kDa. The optimal pH value of this recombinant protein was 7.5. The divalent ions had no significant effect on Per-catalyzed reaction. The K(m) and K(cat)/K(m) for GDP-4-keto-6-deoxy-d-mannose were 0.09 mM and 2.1 x 10(5)M(-1)S(-1), and those for l-glutamate were 2mM and 0.52 x 10(5)M(-1)S(-1), respectively. Per was used to synthesize GDP-perosamine from GDP-mannose together with recombinant GDP-mannose dehydratase (GMD, E.C. 4.2.1.47). The purified GDP-perosamine was identified by MS and NMR. In summary, this work provided a feasible approach for the synthesis of GDP-perosamine which can lead to the study of LPS biosynthesis of pathogenic E. coli O157:H7.

The N-glycosylation mutants (mnn1 and mnn1 och1) show different morphological characteristics at the restrictive and nonpermissive temperature. We deleted the MNN1 to eliminate the terminal alpha1, 3-linked mannose of hypermannosylation and deleted the OCH1 to block the elongation of the main backbone chain. The mnn1 cells exhibited no observable change with respect to the wild-type strain at 28 degrees C and 37 degrees C, but the mnn1 och1 double mutant exhibited defects in cell cytokinesis, showed a slower growth rate, and became temperature-sensitive. Meanwhile, the mnn1 och1 mutant tended to aggregate, which was probably due to the glycolsylation defect. Loss of mannosyl-phosphate-accepting sites in this mutant migth result in reduced charge repulsion between cell surfaces. Pyridylaminated glycans were profiled and purified through an NH(2) column by size-fractionation high-performance liquid chromatography. Matrix assisted laser desoption/ionization time of flight mass spectrometry (MALDI TOF/MS) analysis of the N-glycan structure of the mnn1 och1 mutant revealed that the main component is Man(8)GlcNAc(2).

Peptide- N -( N -acetyl-β-glucosaminyl) asparagine amidase F (PNGase F, EC 3.5.1.52) removes glycan moieties from glycoproteins under relatively mild conditions. This eznyme has been used as a powerful tool in analyzing the structural and biological functions of N-linked glycans of glycoproteins. The PNGase F gene from Flavobacterium meningosepticum was cloned into plasmid pYD1, which enabled regulated expression, secretion and detection. The expression of PNGase F gene at extracellular surface of Saccharomyces cerevisiae was confirmed by immunofluorescence microscopy. Fluorescence activated cell sorter analysis indicated that, after 36 h cultivation, 47.6% of the cell surface was anchored with target proteins. The surface engineered enzyme was confirmed to be active and reached its highest level after induced for 36 h. HPLC analysis showed that the specific activity of the surface-displayed PNGase F was about 12 U/g (cell dry weight).

Using Agrobacterium mediated transient expression method, plant bivalent expression vector pBI121 containing GUS as a report gene was transformed into lettuce (Lactuca sativa). Through designed orthogonal analysis, intact lettuce leaves infiltrated with 200 μM acetosyringone and 0.8 OD600 bacterial suspensions under vacuum for 30 min, then co-cultured at 24 °C for 6 ds produced a maximum GUS protein of 2.5% TSP with 21.39 nmol mg−1 min−1 MU activity, which was 19 times of the control (1.31 nmol mg−1 min−1 MU). Employed these optimized conditions HuIFN-beta was expressed in lettuce leaves. Western blot and antivirus bioactivity analyses confirmed the HuIFN-beta achieved by agrobacterium infiltration had a high biological activity (3.1 × 104 IU/mL). To our knowledge, it is the first detailed orthogonal optimizing study of Agrobacterium mediated transient expression and the first report on the production of the biologically active therapeutic proteins produced by Agrobacterium mediated transient expression in lettuce. In summary, transient expression by Agrobacterium vacuum infiltration can be adopted as an efficient, inexpensive and small-scaled plant expression system for therapeutic protein production.

Fluorophore-assisted carbohydrate electrophoresis (FACE) is a straightforward, sensitive method for determining the presence and relative abundance of individual (oligo)saccharide in a(n) (oligo)saccharide mixture. The single terminal aldehydes of oligoglucoside residues released by acid hydrolysis of β-1, 3-d-glucan from yeast were tagged with the charged fluorophore 8-aminonaphthalene-1,3,6-trisulfonate (ANTS), and separated with high resolution on the basis of size by polyacrylamide gel electrophoresis. ANTS fluorescence labeling was not biased by oligoglucoside length; therefore, band fluorescence intensity was directly related to the relative abundance of individual oligoglucoside moieties in heterogeneous sample. Therefore, FACE represents an accessible, sensitive, and quantitative analytical tool enabling the analysis of (oligo)saccharides derived from different sources.

Studies of rare ketoses have been hampered by a lack of efficient preparation methods. A convenient, efficient, and cost-effective platform for the facile synthesis of ketoses is described. This method enables the preparation of difficult-to-access ketopentoses and ketohexoses from common and inexpensive starting materials with high yield and purity and without the need for a tedious isomer separation step.

UDP-galactose 4-epimerase (EC 5.1.3.2, Gal E) from Escherichia coli catalyzes the reversible reaction between UDP-galactose and UDP-glucose. In this study, the Gal E gene from E. coli, coding UDP-galactose 4-epimerase, was cloned into pYD1 plasmid and then transformed into Saccharomyces cerevisiae EBY100 for expression of Gal E on the cell surface. Enzyme activity analyses with EBY100 cells showed that the enzyme displayed on the yeast cell surface was very active in the conversion between UDP-Glc and UDP-Gal. It took about 3 min to reach equilibrium from UDP-galactose to UDP-glucose.

N -Acetyl glucosamine 1 is selectively converted into 2 without protection of the other hydroxyl groups by allylation of the anomeric alkoxide in N , N -dimethylformamide containing lithium bromide. We use cell density cultures to produce the allylated derivative of penta- N -acetyl-chitopentaose by using 2 as the initial acceptor for the synthesis of 3 in vivo. Upon periodate oxidation, 3 is transferred to 4 . Compound 4 is quickly subjected to sodium borohydride reduction and NH 3 amination, which afforded the target compound 5 . In 5 -binding chitinase assay, it indicates that the chitinase is obviously inactivated by 5 with IC 50 = 4.7 μmol/L.

4'-Modified avermectin derivatives were designed and synthesized. Some of the new synthetic compounds showed excellent in vivo bioactivity against cabbage larvae when compared to commercially available avermectin B1a. In this synthesis, uncommon thioglycosyl sugar donors, prepared from the hydrolysis of natural antibiotics, proved compatible with sugar-macrolide synthesis in the presence of N-iodosuccinimide (NIS) or I2 in N-methylpyrrolidone at room temperature.

In this letter, a hybrid Schottky-ohmic drain structure is proposed for AlGaN/GaN high-electron-mobility transistors on a Si substrate. Without additional photomasks and extra process steps, the hybrid drain design forms a Γ-shaped electrode to smooth the electric field distribution at the drain side, which improves the breakdown voltage and lowers the leakage current. In addition, the hybrid drain provides an auxiliary current path and decreases the on-resistance, in contrast to the devices with a pure Schottky drain. Compared with the conventional ohmic drain devices, the breakdown voltage could be improved up to 64.9%, and the leakage current is suppressed by one order of magnitude without degradation of the specific on-resistance.

The prefrontal cortex (PFC) plays a critical role in cognitive functions, including working memory, attention regulation, behavioral inhibition, as well as memory storage. The functions of PFC are very sensitive to norepinephrine (NE), and even low levels of endogenously released NE exert a dramatic influence on the functioning of the PFC. Activation of β-adrenoceptors (β-ARs) facilitates synaptic potentiation and enhances memory in the hippocampus. However, little is known regarding these processes in the PFC. In the present study, we investigate the role of β2-AR in synaptic plasticity and behavioral memory. Our results show that β2-AR selective agonist clenbuterol facilitates spike-timing-dependent long-term potentiation (tLTP) under the physiological conditions with intact GABAergic inhibition, and such facilitation is prevented by co-application with the cAMP inhibitor Rp-cAMPS. Loading postsynaptic pyramidal cells with Rp-cAMPS, the PKA inhibitor PKI5-24, or the G protein inhibitor GDP-β-S significantly decreases, but does not eliminate, the effect of clenbuterol. Clenbuterol suppresses the GABAergic transmission, while blocking GABAergic transmission by the GABAA receptor blocker partially mimics the effect of clenbuterol. In behavioral tests, a post-training infusion of clenbuterol into mPFC enhances 24-h trace fear memory. In summary, we observed that prefrontal cortical β2-AR activation by clenbuterol facilitates tLTP and enhances trace fear memory. The mechanism underlying tLTP facilitation involves stimulating postsynaptic cAMP-PKA signaling cascades and suppressing GABAergic circuit activities.

A beta 1,3-galactosyltransferase (WbgO) was identified in Escherichia coli O55:H7. Its function was confirmed by radioactive activity assay and structure analysis of the disaccharide synthesized with the recombinant enzyme. WbgO requires a divalent metal ion, either Mn2+ or Mg2+, for its activity and is active between pH 6.0-8.0 with a pH optimum of 7.0. N-acetylglucosamine (GlcNAc) and oligosaccharides with GlcNAc at the non-reducing end were shown to be its preferred substrates and it can be used for the synthesis of type 1 glycan chains from these substrates. Together with a recombinant bacterial GlcNAc-transferase, benzyl beta-lacto-N-tetraoside was synthesized with the purified WbgO to demonstrate the synthetic utility of WbgO. (C) 2009 Elsevier Ltd. All rights reserved.

We demonstrate the syntheses of single crystalline Cu nanobelt and Ag belt-like materials via CTAC-assisted (CTAC, cetyltrimethylammonium chloride) galvanic reductions. The single crystalline face-centered cubic phase Cu nanobelt was prepared by reacting CuCl2(aq) with Al(s) in an aqueous solution of CTAC and HNO3. The Cu nanobelt exhibited a high-quality ribbon-like nanostructure with a thickness less than 15 nm, a width of 30-150 nm, and a length up to 10 microm. The belt-like Ag, with a thickness less than 10 nm, a width of 30-100 nm, a length up to 5 microm, and a novel single crystalline 4H structure, was prepared by reacting AgNO3(aq) and Cu(s) in an aqueous solution of CTAC.

A new compound 2, possessing a tetra-N-acetyl-chitotetraosyl moiety as a constituent, was synthesized by bacterial fermentation, which used allosamizoline 1 as the initial acceptor. A 2-binding chitinase assay, indicated that the chitinase was inactivated by 2 with IC50 = 0.03 microg/mL.

A new compound 7, possessing a tetra-N-acetyl-chitotetraosyl moiety as a constituent, was synthesized by bacterial fermentation which used allosamizoline 6 as the initial acceptor.

The work presented herein is a new noncovalent glycoarray assembly method for microplates created by simply mixing together a carbohydrate and a tetradecylamine. Alpha-mannose was utilized in the model study and product formation was detected by lectin binding. The method can be further extended to array complex carbohydrates.

The work presented herein is a new noncovalent glycoarray assembly method for microplates created by simply mixing together a carbohydrate and a tetradecylamine. alpha-D-Mannopyranoside, alpha-D-glucopyranoside, and alpha-D-galactopyranoside were utilized in model studies and product formations were detected by lectin binding. The method can be extended to study the steric hindrance effect of carbohydrate-protein interactions, namely the structure-function relations of carbohydrates.

Fluorophore-assisted carbohydrate electrophoresis (FACE) is a straightforward, sensitive method for determining the presence and relative abundance of individual (oligo)saccharides in a(n) (oligo)saccharide mixture. The single-terminal aldehydes of oligoglucoside residues released by acid hydrolysis of beta-1,3-D-glucan from yeast were tagged with the charged fluorophore ANTS (8-aminonaphthalene-1,3,6-trisulphonate), and separated with high resolution on the basis of size by PAGE. ANTS fluorescence labelling was not biased by oligoglucoside length; therefore band fluorescence intensity was directly related to the relative abundance of individual oligoglucoside moieties in a heterogeneous sample. FACE analysis revealed that the major oligoglucoside mixture released by acid hydrolysis from beta-1,3-D-glucan was composed of monosaccharide, disaccharide, trisaccharide, tetrasaccharide, pentasaccharide, hexasaccharide, heptasaccharide and octasaccharide, and the order of abundance from high to low was trisaccharide, monosaccharide, disaccharide, tetrasaccharide, pentasaccharide, hexasaccharide, heptasaccharide and octasaccharide respectively. In conclusion, FACE represents an accessible, sensitive and quantitative analytical tool enabling the characterization of a(n) (oligo)saccharide mixture.

Cell density cultivation of recombinant Escherichia coli strains harboring the nodC gene (encoding chitooligosaccharide synthase) from Azorhizobium caulinodans has been previously described as a practical method for the preparation of gram-scale quantities of penta- N -acetyl-chitopentaose. We have now extended this method to the production of allylated derivative of penta- N -acetyl-chitopentaose by using allyl 2-acetamido-2-deoxy-β- d -glucopyranoside ( 2 ) as the initial acceptor for the synthesis of target pentaoside in vivo.

Two contact engineering approaches are proposed and investigated to enhance the breakdown voltage VBK in GaN-on-Si power devices, including the hybrid Schottky–ohmic-drain structure for AlGaN/GaN HEMTs and the selective Si-diffusion structure for AlGaN/GaN SBDs. With the hybrid Schottky–ohmic drain, the devices showed a zero onset voltage and reduced off-state leakage current by one order of magnitude, compared with that of the traditional ohmic-drain devices. The breakdown voltage was also enhanced with comparable on-resistance. For the SBDs with the selective silicon-diffusion layer underneath ohmic metal at the cathode, a low-contact resistance Rc of 0.2 Ω mm and a smooth ohmic metal morphology were obtained. The SBDs with the additional silicon diffusion layer showed enhanced VBK, compared with that of the conventional SBDs. The results demonstrate that the proposed contact engineering approaches are useful for the breakdown voltage enhancement of GaN-on-Si power devices.