New tirucallane-type triterpenoids from the resin of Boswellia carteriiand their NO inhibitory activities.

Six new tirucallane-type triterpenoids (1-6), along with ten known triterpenoids, were isolated from methylene chloride extract of the resin of Boswellia carterii Birdw. By the application of the comprehensive spectroscopic data, the structures of the compounds were clarified. The experimental electronic circular dichroism spectra were compared with those calculated, which allowed to assign the absolute configurations. Compounds 5 and 6 possesed a 2, 3-seco tirucallane-type triterpenoid skeleton, which were first reported. Their inhibitory activity against NO formation in LPS-activated BV-2 cells were evaluated. Compound 9 showed appreciable inhibitory effect, with an IC50 value of 7.58 ± 0.87 µmol·L-1.

Energy Manipulation in Lanthanide-Doped Core-Shell Nanoparticles for Tunable Dual-Mode Luminescence toward Advanced Anti-Counterfeiting.

Developing advanced luminescent materials and techniques is of significant importance for anti-counterfeiting applications, and remains a huge challenge. In this work, a new and efficient approach for achieving efficient dual-mode luminescence with tunable color outputs via Gd3+ -mediated interfacial energy transfer, Ce3+ -assisted cross-relaxation, and core-shell nanostructuring strategy is reported. The introduction of Ce3+ into the inner core not only serves the regulation of upconversion emission, but also facilitates the ultraviolet photon harvesting and subsequent energy transfer to downshifting (DS) activators in the outer shell layer. Furthermore, the construction of the core@shell nanoarchitecture enables the spatial separation of upconverting activators and DS centers, which greatly suppresses their adverse cross-relaxation processes. Consequently, efficient and multicolor-tunable dual-mode emissions can be simultaneously observed in the pre-designed NaGdF4 :Yb/Ho/Ce@NaYF4 :X (X = Eu, Tb, Sm, Dy) core-shell nanostructures under 254 nm ultraviolet light and 980 nm laser excitation. The proof-of-concept experiment demonstrates that 2D-encoded patterns based on dual-mode emitting nanomaterials are very promising for anti-counterfeiting applications. It is believed that this preliminary study will advance the development of the fluorescent materials for potential applications in anti-counterfeiting and optical multiplexing.

Efficient dual-mode luminescence from lanthanide-doped core-shell nanoarchitecture for anti-counterfeiting applications.

Fluorescent anti-counterfeiting technique is generally based on the development of luminescent materials, which generally exhibit single-mode emissions under single-wavelength excitation, thus resulting in a poor anti-fake effect. To improve the anti-forgery performance of fluorescent anti-counterfeiting approaches, dual-mode luminescent nanoparticles with the form of a ß-NaGdF4:Yb/Ho/Ce@ß-NaYF4:Tb/Eu core-shell structure have been skillfully designed and synthesized by a co-precipitation strategy. Through the cross-relaxation process between Ce3+ and Ho3+ ions in the inner core region, the up-conversion luminescence colors of the as-synthesized samples can be turned from green to yellow and finally to red when adjusting the dopant concentration of Ce3+ in the core. By selecting Ce3+ as the sensitizer for harvesting the energy of incident ultraviolet (UV) light and introducing Gd3+ as the ideal intermediate for subsequent energy migration, the down-converting emission colors of the as-obtained samples are also regulated from green to red via a Gd3+-assisted interface energy transfer processes (Ce3+ → Gd3+ → Tb3+, Ce3+ → Gd3+ → Tb3+ → Eu3+). Consequently, dual-mode luminescence with multi-color outputs can be achieved in the pre-designed core-shell nanostructure under the excitation of a 980 nm near-infrared laser and 254 nm UV light. The designed nanoarchitecture with bright dual-mode emissions and tunable colors greatly improves the ability of modern anti-counterfeiting, demonstrating its promising applications in anti-fake and optical multiplexing.

Sulfotransferase-catalyzed biotransformation of liguzinediol and comparison of its metabolism in different species using UFLC-QTOF-MS.

Liguzinediol (2,5-dihydroxymethyl-3,6-dimethylpyrazine, LZDO) is a potential agent for the low-risk treatment of heart failure. 2-N-acetylcysteine-LZDO (2-NAC-LZDO) and 2-cysteine-LZDO (2-Cys-LZDO) are major LZDO metabolites found in the pharmacokinetic studies of rats and beagle dogs. To elucidate the biotransformation pathway and related enzymes, an incubation system with 3'-phosphoadenosine-5'-phosphosulfate (PAPS) as a cofactor and N-acetylcysteine (NAC) as a trapping agent was established using liver cytosol. An ultra-flow liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UFLC-QTOF-MS) method was used to identify the major metabolites. 2-NAC-LZDO could be detected among four species (humans, monkeys, dogs, and rats) and is the dominant metabolite in human liver cytosol (HLC). The sulfotransferase (SULT) inhibitors 2,6-dichloro-4-nitrophenol (DCNP) and quercetin at a concentration of 1 µM, suppressed 2-NAC-LZDO formation in HLC by 87 and 46%, respectively. This result suggested that sulfotransferase was involved in 2-NAC-LZDO formation. The metabolism of LZDO in different species indicated that SULT activity in dogs, rats, and monkeys was higher than that in humans. Further SULT phenotyping revealed that SULT1A1 is the predominant enzyme involved in the sulfation of LZDO. The underlying mechanism for the biotransformation of LZDO was demonstrated. The potential pathway is via the sulfation of LZDO to form sulfate, and the spontaneous cleavage of the sulfate group to generate highly reactive electrophilic cations, which can bind to NAC to form the major metabolites.

Two new xanthone epimers from the processed gamboge.

Two new xanthones, gambogollic acid (1), epigambogollic acid (2), together with three rare compounds, gambogellic acid (3), epigambogellic acid (4) and gambogic acid (5), were isolated from the processed gamboge. The new structures were determined by 1D and 2D NMR spectroscopic analysis. And the cytotoxicity of these five compounds was evaluated against human hepatoma carcinoma and human lung adenocarcinoma cell. Two new compounds showed excellent antitumor activity. All five compounds exhibited inhibitory effect against SMMC-7221cell and A549 cell.

Structural disorder in metallic glass-forming liquids.

We investigated structural disorder by a new structural parameter, quasi-nearest atom (QNA), in atomistic configurations of eight metallic glass-forming systems generated through molecular dynamics simulations at various temperatures. Structural analysis reveals that the scaled distribution of the number of QNA appears to be an universal property of metallic liquids and the spatial distribution of the number of QNA displays to be clearly heterogeneous. Furthermore, the new parameter can be directly correlated with potential energy and structural relaxation at the atomic level. Some straightforward relationships between QNA and other properties (per-atom potential energy and α-relaxation time) are introduced to reflect structure-property relationship in metallic liquids. We believe that the new structural parameter can well reflect structure disorder in metallic liquids and play an important role in understanding various properties in metallic liquids.

Pharmacological kinetics of BmK AS, a sodium channel site 4-specific modulator on Nav1.3.

OBJECTIVE: In this study, the pharmacological kinetics of Buthus martensi Karsch (BmK) AS, a specific modulator of voltage-gated sodium channel site 4, was investigated on Na(v)1.3 expressed in Xenopus oocytes. METHODS: Two-electrode voltage clamp was used to record the whole-cell sodium current. RESULTS: The peak currents of Na(v)1.3 were depressed by BmK AS over a wide range of concentrations (10, 100, and 500 nmol/L). Most remarkably, BmK AS at 100 nmol/L hyperpolarized the voltage-dependence and increased the voltage-sensitivity of steady-state activation/inactivation. In addition, BmK AS was capable of hyperpolarizing not only the fast inactivation but also the slow inactivation, with a greater preference for the latter. Moreover, BmK AS accelerated the time constant and increased the ratio of recovery in Na(v)1.3 at all concentrations. CONCLUSION: This study provides direct evidence that BmK AS facilitates steady-state activation and inhibits slow inactivation by stabilizing both the closed and open states of the Na(v)1.3 channel, which might result from an integrative binding to two receptor sites on the voltage-gated sodium channels. These results may shed light on therapeutics against Na(v)1.3-targeted pathology.

[Establishment of sandwich ELISA for detecting Staphylococcal enterotoxin B in different matrices].

AIM: To establish sandwich ELISA for the detection of Staphylococcal enterotoxin B(SEB) and characterize the sensitivity and specificity of it in different materials. METHODS: The anti-SEB monoclonal antibodies (mAb) B4 and D6 were employed as capture antibody and detecting antibody respectively after being purified by Q sepharose fast flow chromatography and horseradish peroxidase(HRP) conjugation. RESULTS: The sensitivity of this assay reached 0.2 ng of SEB per mL of PBS with BSA and fetal bovine serum. It reached 0.39 ng of SEB per mL of 50 g/L skim milk, human urine and water. The concentration curve generated from SEB standard curve was linear with the range of 0.78-12.5 microg/L, (r(2)=0.99). This assay was highly reproducible and the coefficient of variation(CV) was less than 10%.No cross-reactivity between SEA and SECl was found. CONCLUSION: This assay offers a viable method with high sensitivity and specificity for detecting SEB and it may be used for SEB detection in clinical application and food samples.

[Establishment of chemiluminescence immunoassay for detecting Staphylococcal enterotoxin B and C1].

AIM: To establish chemiluminescence immunoassay (CLIA) for detecting staphylococcal enterotoxin B (SEB) and C1 (SEC1) and compare its sensitivity and stability with ELISA. METHODS: The anti-SEB and SEC1 monoclonal antibodies (mAb) were purified by Q Sepharose Fast Flow chromatographic column. The alkaline phosphatase (AP) conjugated mAbs FMMU-SEB.D6 and FMMU-SEC1.C4 were used as detecting antibodies and the FMMU-SEB.B4 and FMMU-SEC1.G8 mAbs were used as coating antibodies in both methods. Phenolphthalein monophosphate (PMP) and lumigen APS-5 were employed as substrates for AP in ELISA and CLIA, respectively. The light was detected and measured by the GENios analyzer (TECAN Group Ltd.). The sensitivities and detect ranges of CLIA and ELISA methods were compared. RESULTS: Compared with ELISA, CLIA was more sensitive (0.1 ng/mL vs 0.39 ng/mL) and timesaving. Furthermore, the liner range of CLIA was broader than that of ELISA (0.78-50 ng/mL vs 3.125-50 ng/mL). CONCLUSION: CLIA for detecting SEB and SEC1 are established successfully which may be useful in food monitoring, epidemiology survey and detecting SE contaminated samples in environment.

Identification of CD226 ligand on colo205 cell surface.

AIM: To confirm the existence of CD226 ligand and its distribution, which is a novel molecule cloned in 1996. METHODS: The mRNA was extracted from TPA activated Jurkat cells and used as a template for reverse-transcription. After PCR amplification, the fragment including CD226 extracellular region and the splice donor sequence "ACTTACCTGT" was obtained and cloned into fusion expression vector pIG. The recombinant vector pCD226/Ig was transfected in COS-7 cells by DEAE-Dextran method, the secreting fusion protein was identified by Sandwich ELISA, and was purified by anti-CD226 affinity chromatography. This fusion protein was used as a probe in the investigation of CD226 ligand by immunohistochemistry. Existence of CD226 ligand was further identified by adhesion experiment. RESULTS: Expression of a secreting fusion protein was identified by sandwich ELISA,indicating that both CD226 extracellular domain and IgGFc domain could be recognized respectively by anti-CD226 and anti-hIgFc mAb. About 130g CD226/Ig fusion protein could be obtained from 100mL COS-7 culture supernatants by anti-CD226 affinity chromatography purification. SDS-PAGE showed that this fusion protein has a molecular mass of 83ku. It was confirmed by immunohistochemistry that CD226 ligand expressed on the Colo205 cells, but not on Jurkat cell, U937 cell and mixed lymphocyte culture cells. In adhesive assay, resting Jurkat cells did not have significant adhesion to Colo205 cells. In contrast, activated Jurkat cells could bind to colon carcinoma Colo205 cells and this adhesive reaction could be blocked by CD226/Ig fusion protein or anti-CD226 mAb. Immunochemical experiment showed that Colo205 cells could be specifically stained by CD226/Ig, indicating that CD226 ligand exists on the surface of Colo205 cells. CONCLUSION: Existence of CD226 ligand on the surface of Colo205 cells was identified by immunohistochemistry and adhesion blocking experiment. In addition, the secreting CD226/Ig fusion protein prepared in this study will be a potential tool for further investigation of CD226 ligand.