XTH31, encoding an in vitro XEH/XET-active enzyme, regulates aluminum sensitivity by modulating in vivo XET action, cell wall xyloglucan content, and aluminum binding capacity in Arabidopsis.

Xyloglucan endohydrolase (XEH) and xyloglucan endotransglucosylase (XET) activities, encoded by xyloglucan endotransglucosylase-hydrolase (XTH) genes, are involved in cell wall extension by cutting or cutting and rejoining xyloglucan chains, respectively. However, the physiological significance of this biochemical activity remains incompletely understood. Here, we find that an XTH31 T-DNA insertion mutant, xth31, is more Al resistant than the wild type. XTH31 is bound to the plasma membrane and the encoding gene is expressed in the root elongation zone and in nascent leaves, suggesting a role in cell expansion. XTH31 transcript accumulation is strongly downregulated by Al treatment. XTH31 expression in yeast yields a protein with an in vitro XEH:XET activity ratio of >5000:1. xth31 accumulates significantly less Al in the root apex and cell wall, shows remarkably lower in vivo XET action and extractable XET activity, has a lower xyloglucan content, and exhibits slower elongation. An exogenous supply of xyloglucan significantly ameliorates Al toxicity by reducing Al accumulation in the roots, owing to the formation of an Al-xyloglucan complex in the medium, as verified by an obvious change in chemical shift of (27)Al-NMR. Taken together, the data indicate that XTH31 affects Al sensitivity by modulating cell wall xyloglucan content and Al binding capacity.

Highly efficient and catalyst-free synthesis of substituted thioureas in water.

A highly efficient and catalyst-free method for the synthesis of substituted thiourea derivatives is presented. The synthesis is performed through the reaction of thiazolidine-2-thiones with various amines in water. A sound number of thioureas with both unsymmetrical and symmetrical architectures have been obtained in good to excellent yields.

LC/MS guided isolation of alkaloids from lotus leaves by pH-zone-refining counter-current chromatography.

The traditional methods used in natural product separation primarily target the major components and the minor components may thus be lost during the separation procedure. Consequently, it's necessary to develop efficient methods for the preparative separation and purification of relatively minor bioactive components. In this paper, a LC/MS method was applied to guide the separation of crude extract of lotus (Nelumbo nucifera Gaertn.) leaves whereby a minor component was identified in the LC/MS analysis. Afterwards, an optimized pH-zone-refining CCC method was performed to isolate this product, identified as N-demethylarmepavine. The separation procedure was carried out with a biphasic solvent system composed of hexane-ethyl acetate-methyl alcohol-water (1:6:1:6, v/v) with triethylamine (10 mM) added to the upper organic phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase eluent. Two structurally similar compounds--nuciferine and roemerine--were also obtained from the crude lotus leaves extract. In total 500 mg of crude extract furnished 7.4 mg of N-demethylarmepavine, 45.3 mg of nuciferine and 26.6 mg of roemerine with purities of 90%, 92% and 96%, respectively. Their structures were further identified by HPLC/ESI-MSn, FTICR/MS and the comparison with reference compounds.

Self-assembly and host-guest interaction of metallomacrocycles using fluorescent dipyrazole linker with dimetallic clips.

By employing diimine ligands coordinated dimetallic clips ([(bpy)2Pd2(NO3)2](NO3)2 or [(phen)2Pd2(NO3)2](NO3)2, where bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) as the corner and anthracene-, naphthalene-, and benzene-based dipyrazolate dianions as the linker, a series of positively charged metallomacrocycles ([M4L2]4+ or [M8L4]8+) have been synthesized through a directed self-assembly method in aqueous solution. Every macrocycle has a cavity to bind solvent molecules or anions. The structures were characterized by elemental analysis, 1H and 13C NMR, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis for compound 1 x 4 PF6(-) (1 = {[(bpy)Pd]4L(1)2}4+), 3 x 4 PF6(-) x 8 CH3CN x H2O (3 = {[(bpy)Pd]4L(2)2}4+), and 7 x 4 PF6(-) x 6 H2O (7 = {[(bpy)Pd]4L(5)2}4+). The 1:1 host-guest complexation for anthracene-based dipyrazolate-bridged macrocycles with aromatic guests was investigated via UV-vis and fluorescent titration.

Investigation of Invigorating Qi and Activating Blood Circulation Prescriptions in Treating Qi Deficiency and Blood Stasis Syndrome of Ischemic Stroke Patients: Study Protocol for a Randomized Controlled Trial.

Ischemic stroke (IS) is characterized by high morbidity and high mortality. The integration of Traditional Chinese medicine (TCM) and western medicine has shown promising benefits in relieving symptoms, promoting neurological recovery, and improving the quality of life of patients with IS. In TCM, Qi-deficiency along with blood-stasis (QDBS) syndrome is one of the common types of IS that is treated by invigorating Qi and activating blood circulation. In TCM theory, improving the corresponding degree of prescription-syndrome correlation (PSC) is helpful to improve clinical efficacy. In this study, we intend to use similar prescriptions that invigorate Qi and activate blood circulation: Buyang Huanwu granules (BHG), Naoxintong capsules (NXTC), and Yangyin Tongnao granules (YTG). The goal is to evaluate their level of PSC inpatients with IS with QDBS syndrome and find relevant biomarkers to provide an objective basis for precise treatment of TCM and improve the clinical therapeutic effects. A multicenter, randomized, double-blinded, and placebo-controlled intervention trial will be conducted in IS patients with QDBS syndrome, followed by an add-on of Chinese patent medicine. A total of 160 subjects will be randomly assigned to the BHG, NXTC, YTG, and placebo groups in a 1:2:1:1 allocation ratio. All subjects will undergo 28 days of treatment and then followed for another 180 days. The primary outcome is the changes in the National Institutes of Health Stroke Scale score after 28 days of medication. The secondary outcomes include the modified Rankin scale score, activity of daily living scale score, and TCM symptom score. Data will be analyzed in accordance with a predefined statistical analysis plan. Ethical approval of this trial has been granted by the Research Ethics Committee of the First Affiliated Hospital of Zhejiang Chinese Medical University (ID: 2017-Y-004-02). Written informed consent of patients will be required. This trial is registered in the Chinese Clinical Trial Registry (ChiCTR1800015189), and the results will be disseminated to the public through peer-reviewed journals and academic conferences.

Chemo-/regioselective synthesis of 6-unsubstituted dihydropyrimidinones, 1,3-thiazines and chromones via novel variants of Biginelli reaction.

A novel and facile cascade Biginelli-like assembly employing enaminone, aldehyde and urea/thiourea has been developed, which provides a highly chemo- and regioselective synthesis of new dihydropyrimidinones, 1,3-thiazines and chromones by altering particular functional groups in the reactants.

Novel regioselectivity: three-component cascade synthesis of unsymmetrical 1,4- and 1,2-dihydropyridines.

The three-component sequential reaction of alpha,beta-unsaturated aldehydes, amines, and enaminones proceeded smoothly to give 1,3,4-trisubstituted 1,4-dihydropyridines in aqueous DMF. Moreover, the unexpected regioselective formation of 1,2-dihydropyridines has been observed for the first time in such an approach. On the basis of a systematic study, the novel regioselectivity could be assigned both to steric and electronic effects originating from the amine partner.

Scavenging activity and mechanism study of ferulic acid against reactive carbonyl species acrolein.

Acrolein, known as one of the most common reactive carbonyl species, is a toxic small molecule affecting human health in daily life. This study is focused on the scavenging abilities and mechanism of ferulic acid and some other phenolic acids against acrolein. Among the 13 phenolic compounds investigated, ferulic acid was found to have the highest efficiency in scavenging acrolein under physiological conditions. Ferulic acid remained at (3.04±1.89)% and acrolein remained at (29.51±4.44)% after being incubated with each other for 24 h. The molecular mechanism of the detoxifying process was also studied. Detoxifying products, namely 2-methoxy-4-vinylphenol (product 21) and 5-(4-hydroxy-3-methoxyphenyl)pent-4-enal (product 22), were identified though nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS), after the scavenging process. Ferulic acid showed significant activity in scavenging acrolein under physiological conditions. This study indicates a new method for inhibiting damage from acrolein.

Assay of dried blood spot from finger prick for sodium valproate via ink auxiliary headspace gas chromatography mass spectrometry.

Sodium valproate is the most commonly used antiepileptic drug that patients need to keep taking over a long period of time or on a permanent basis. Its blood concentration should be accurately detected to avoid toxicity or side-effects, especially for children and the aged. Dried blood spot (DBS) sampling from finger prick is a minimally invasive and patient-friendly procedure for blood collection. However, there are few studies about rapid detection of sodium valproate in DBS samples in current literatures. In this work, we developed an ink auxiliary headspace gas chromatography mass spectrometry (GC-MS) strategy for direct detection of sodium valproate in DBS from epilepsy patients, which does not need extra solvent extraction or elution. It was discovered that carbon black ink could provide better capacity of heat absorption and dissociation, and higher quality of headspace sampling. The detection sensitivity has been improved with reported headspace GC-MS methods, and the limit of quantitation could reach to 200 ng/mL. Finally, this strategy was practically applied to quantify sodium valproate in DBS samples from 29 epilepsy patients. The result showed higher accuracy with lower relative errors by comparing with the clinical immunoassay results. In conclusion, we developed a direct detection method for DBS samples that is suitable for high-throughput clinical test with great potential for clinical application.

New tyrosinase inhibitory sesquiterpenes from Chloranthus henryi.

Chemical investigation of the leaves and stems of Chloranthus henryi resulted in the isolation and characterization of two new eudesmane-type sesquiterpenes, and two new germacrane-type sesquiterpenes, together with two known compounds. The inhibitory activities against tyrosinase of all isolates were also evaluated.

Preliminary studies on the chemical characterization and antioxidant properties of acidic polysaccharides from Sargassum fusiforme.

In order to investigate the antioxidant properties of the polysaccharides from the brown alga Sargassum fusiforme, the crude polysaccharides from S. fusiforme (SFPS) were extracted in hot water, and the lipid peroxidation inhibition assay exhibited that SFPS possessed a potential antioxidant activity. Hence, two purely polymeric fractions, SFPS-1 and SFPS-2 were isolated by the column of DEAE (2-diethylaminoethanol)-Sepharose Fast Flow, with their molecular weights of 51.4 and 30.3 kDa determined by high performance gel permeation chromatography (HPGPC). They were preliminarily characterized using chemical analysis in combination of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies and found to contain large amounts of uronic acids and beta-glycosidical linkages. The antioxidant activities of these two SFPS fractions were evaluated using superoxide and hydroxyl radical-scavenging assays. The results show that the antioxidant ability of SFPS-2 was higher than that of SFPS-1, probably correlating with the molecular weight and uronic acid content.

[Studies on chemical constituents and antibacterial activity from n-butanol extract of Sarcandra glabra].

OBJECTIVE: To study the chemical constituents and the antibacterial activity from n-butanol extract of Sarcandra glabra. METHOD: The compounds were isolated by Diaion HP-20, Sephadex LH-20, MCI CHP-20 and silica gel column chromatographic methods. Their structures were identified on the basis of physicochemical and spectroscopic analysis. The antibacterial effect of the compounds were measured against Staphylococcus aureus by filterpaper slice method, finally the antibacterial ring in each group was recorded after 24 hours. RESULT: Seven constituents were isolated and elucidated as 5, 7, 3', 4'-tetrahydroxy-6-C-beta-D-glucopyranosylflavanone (1), kaempferol-3-O-beta-D-glucuronide (2), fraxidin (3), isofraxidin (4), isofraxidin-7-O-beta-D-glucopyranoside (5), kaempferol (6), pinostrobin (7). Diameters (in mm) of antibacterial ring in the compounds 2, 5, 6 were orderly recorded as follows: 14.67 +/- 0.08, 11.14 +/- 1.06, 8.26 +/- 1.26 and the compound 4 is not effective. CONCLUSION: Compounds 1-3 and 5 were isolated from S. glabra for the first time.

[Effect of puerarin and ligustrazine on cultured hippocampal neurons injury induced by Abeta25-35].

OBJECTIVE: To investigate the changes of MDA, SOD, LDH of cultured hippocampal neurons injury induced by amyloid-beta protein (Abeta 25-35) and the protective effect of puerarin and ligustrazine. METHOD: Primary hippocampal neurons were cultured and induced by Abeta 25-35. The concentrations of MDA, SOD and LDH in cultured hippocampal neurons were measured after exposed to Abeta 25-35, puerarin and ligustrazine. RESULT: The Alzheimer disease (AD) model was successfully established in cultured hippocampal neurons. AD group has remarkably increased MDA and LDH level, and decreased SOD level, Piracetan group and combined application group of have remarkably decreased MDA and LDH level and increased SOD level, compared with AD group (P < 0.01). Ligustrazine together with puerarin group has remarkably decreased MDA and LDH level and increased SOD level, compared with ligustrazine group and puerarin group (P < 0.05). CONCLUSION: Abeta 25-35 can induce cultured hippocampal neurons injury, combined application of ligustrazine, and puerarin can alleviate the injury.

Self-assembly of tripyrazolate-linked macrotricyclic M(12)L(4) cages with dimetallic clips.

[structure: see text]. The self-assembly in aqueous solution of tripyrazolate trianion linkers (H3L = 1 and 2) with coordinated dimetallic clips leads to the formation of Pd12L4 cages with interior cavities of 1800 Angstroms3 and 1500 Angstroms3, respectively, confirmed by 1H NMR, 13C NMR, cold spray ionization mass spectrometry (CSI-MS), and single-crystal X-ray analysis.

In vitro assessment of gastrointestinal viability of two photosynthetic bacteria, Rhodopseudomonas palustris and Rhodobacter sphaeroides.

The objectives of this study were to assess the potential of two photosynthetic bacteria (PSB), Rhodopseudomonas palustris HZ0301 and Rhodobacter sphaeroides HZ0302, as probiotics in aquaculture. The viability of HZ0301 and HZ0302 in simulated gastric transit conditions (pH 2.0, pH 3.0 and pH 4.0 gastric juices) and in simulated small intestinal transit conditions (pH 8.0, with or without 0.3% bile salts) was tested. The effects of HZ0301 and HZ0302 on the viability and permeability of intestinal epithelial cell in primary culture of tilapias, Oreochromis nilotica, were also detected. All the treatments were determined with three replicates. The simulated gastric transit tolerance of HZ0301 and HZ0302 strains was pH-dependent and correspondingly showed lower viability at pH 2.0 after 180 min compared with pH 3.0 and pH 4.0. Both HZ0301 and HZ0302 were tolerant to simulated small intestine transit with or without bile salts in our research. Moreover, there was no significant difference (P>0.05) among three treatments including the control and the groups treated with HZ0301 or HZ0302 both in intestinal epithelial cell viability and membrane permeability, showing no cell damage. In summary, this study demonstrated that HZ0301 and HZ0302 had high capacity of upper gastrointestinal transit tolerance and were relatively safe for intestinal epithelial cells of tilapias.

[Study on triterpenes of Microtropis tiflora].

OBJECTIVE: To study the chemical constituents of Microtropis triflora. METHOD: The compounds were isolated by chromatography on silica gel and Sephadex LH-20. There structures were elucidatedby by chemical methods and spectral analysis. RESULT: Five triterpenoids were isolated and elucidated as friedelin (1), 3-oxo-28-friedelanoic acid (2), 29-hydroxy-3-friedelanone (3), salaspermic acid (4), orthosphenic acid (5). CONCLUSION: Compounds 1-5 are all isolated from M. triflora for the first time.

[Study on effect of different combinations of traditional Chinese medicine preparation active parts on metabolism of puerarin in plasma of rats].

OBJECTIVE: To build an experimental method to determine the content of puerarin in plasma, observe the effect of different combinations of traditional Chinese medicine preparation active parts on metabolism of puerarin in plasma of rats suffering cerebral ischemia attack after being orally administered the main active parts of Yangyin Tongnao granules. METHOD: Absorption of puerarin in plasma was extracted by acetonitrile. Using hydroxybenzoate as interior standard, methanol-0.5% acetic acid water solution as mobile phase, ODS C(18) chromatography column (4.6 mm x 150 mm, 5 microm) as stationary phase, puerarin was detected at 248 nm. RESULT: There is a good linear relationship for puerarin in the range 0.025-3.2 microg x mL-1, RSD < 10%, and the average recovery is 97.6%. CONCLUSION: The method is sensitive, reliable, and can be well applied in this experiment. It can provide a method for determination of active components in TCM preparation in vitro. Different compatibility influences metabolism of components.

Hydrolytic cleavage of both CS2 carbon-sulfur bonds by multinuclear Pd(II) complexes at room temperature.

Developing homogeneous catalysts that convert CS2 and COS pollutants into environmentally benign products is important for both fundamental catalytic research and applied environmental science. Here we report a series of air-stable dimeric Pd complexes that mediate the facile hydrolytic cleavage of both CS2 carbon-sulfur bonds at 25 °C to produce CO2 and trimeric Pd complexes. Oxidation of the trimeric complexes with HNO3 regenerates the dimeric starting complexes with the release of SO2 and NO2. Isotopic labelling confirms that the carbon and oxygen atoms of CO2 originate from CS2 and H2O, respectively, and reaction intermediates were observed by gas-phase and electrospray ionization mass spectrometry, as well as by Fourier transform infrared spectroscopy. We also propose a plausible mechanistic scenario based on the experimentally observed intermediates. The mechanism involves intramolecular attack by a nucleophilic Pd-OH moiety on the carbon atom of coordinated µ-OCS2, which on deprotonation cleaves one C-S bond and simultaneously forms a C-O bond. Coupled C-S cleavage and CO2 release to yield [(bpy)3Pd3(µ3-S)2](NO3)2 (bpy, 2,2'-bipyridine) provides the thermodynamic driving force for the reaction.

The nisin-controlled gene expression system: construction, application and improvements.

Lactic acid bacteria are widely used in industrial fermentation. The potential use of these bacteria as homologous and heterologous protein expression hosts has been investigated extensively. The NIsin-Controlled gene Expression system (the NICE system) is an efficient and promising gene expression system based on the autoregulation mechanism of nisin biosynthesis in the Lactococcus lactis. In the NICE system, the membrane-located histidine kinase NisK senses the inducing signal nisin and autophosphorylates, then transfers phosphorous group to intracellular response regulator protein NisR which activates nisA promoter to express the downstream gene(s). The NICE system allows regulated overproduction of a variety of interest proteins by several Gram-positive bacteria, especially L. lactis. The essential elements for system construction, its application for expression of some biotechnologically important proteins and further improvements of this system are discussed.