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A supramolecular chiral electrode was constructed by layer-by-layer assembly of gold nanoparticles (AuNPs) and an S-chiral multifarene [3,2,1] (S-CMF) on the surface of a glassy carbon electrode, which was applied for the electroreduction of acetophenone. The host-guest encapsulation of the substrate within the chiral cavity was confirmed by 1H NMR, fluorescence titration, and molecular simulation. The composite on the electrode surface was characterized by electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM). Optimization of the electrolysis process was performed to give a high yield of 70.9% and high enantioselectivity of 63.9% ee, which exhibited superior reactivity to the previously reported materials. The repeatability of the experiment was tested via five separate experiments and indicated consistent stability, recyclability, and reusability of the novel chiral electrode. The proposed mechanism involved supramolecular encapsulation, two single-electron transfer steps, and proton addition. The chiral electroorganic reduction was extended to more substrates to provide successful yields and enantioselectivity.

Oritavancin is a new-generation semisynthetic lipoglycopeptide antibiotic used to prevent the spread of vancomycin-resistant Gram-positive bacteria. The glycopeptide A82846B is the direct precursor of oritavancin. Considering the structural similarity between A82846B and vancomycin, the vancomycin producer Amycolatopsis orientalis was used as a chassis for the construction of a strain producing high-quality A82846B. To construct the A82846B synthetic pathway, we established a highly efficient CRISPR-Cas12a system by optimizing the conditions of conjugation and by screening the regulatory elements in the A. orientalis, which is difficult to be genetically manipulated. The efficiency of gene knockout was almost 100%. The glycosyltransferases module (gtfDE) and glycosyl synthesis module (vcaAEBD) in the vancomycin gene cluster were replaced with the corresponding glycosyltransferases module (gtfABC) and glycosyl synthesis module (evaAEBD) in the A82846B cluster, respectively. A82846B was successfully produced by the artificially constructed synthetic pathway. Moreover, the titer of A82846B was increased 80% by expressing the pathway-specific regulatory strR. This strategy has excellent potential for remodification of natural products to solve antibiotic resistance.

A supramolecular strategy was developed for electrocatalytic water splitting in the presence of a macrocyclic compound. The improvement in the oxygen evolution reaction (OER) was observed on the surface of an electrode modified via the facile layer-by-layer assembly of polypyrrole (PPy), reduced graphene oxide (rGO) and cucurbit[6]uril (Q[6]) in sequence. The electrochemical performance was evaluated, and the results indicate the remarkable activity of the proposed supramolecular electrocatalyst toward the OER in alkaline media. The morphology and chemical structure of the electrocatalyst were estimated before and after the OER process. Linear sweep voltammetry measurements suggested that a current density of 10 mA cm−2 at an overpotential of 377 mV was achieved, which is very close to the value of IrO2 under the same conditions, and the calculated Tafel slope of 167 mV dec−1 and electrochemical impedance spectroscopy results imply that a fast charge transfer occurs on the electrode with the functionalization of Q[6]. The developed catalyst could be considered as a potential alternative material for high-efficiency electrocatalytic OER.

Background CRISPR/Cas9 systems have been repurposed as canonical genome editing tools in a variety of species, but no application for the model strain Rhodobacter sphaeroides 2.4.1 was unveiled. Results Here we showed two kinds of programmable base editing systems, cytosine base editors (CBEs) and adenine base editors (ABEs), generated by fusing endonuclease Cas9 variant to cytosine deaminase PmCDA1 or heterodimer adenine deaminase TadA–TadA*, respectively. Using CBEs, we were able to obtain C-to-T mutation of single and double targets following the first induction step, with the efficiency of up to 97% and 43%; while the second induction step was needed in the case of triple target, with the screening rate of 47%. Using ABEs, we were only able to gain A-to-G mutation of single target after the second induction step, with the screening rate of 30%. Additionally, we performed a knockout analysis to identify the genes responsible for coenzyme Q10 biosynthesis and found that ubiF, ubiA, ubiG, and ubiX to be the most crucial ones. Conclusions Together, CBEs and ABEs serve as alternative methods for genetic manipulation in Rhodobacter sphaeroides and will shed light on the fundamental research of other bacteria that are hard to be directly edited by Cas9-sgRNA.

An electrochemiluminescence (ECL) sensor based on a benzo[3]uril-modified glassy carbon electrode with sensitized luminescence, with the coexistence of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as the coreactant, was successfully constructed. The sensitization mechanism was proposed by analyzing the results of the control experiments for establishing the relationship of the luminescence effect with the concentration of HEPES. Under the optimized conditions, the fabricated sensor system was applied for the detection of Fe3+ in an aqueous solution with good sensitivity and selectivity. A low detection limit of 0.41 nM was achieved, indicating superior sensor performance over the previous analytical methods. The ECL sensor system was employed for the detection of Fe3+ in human serum samples to produce excellent recoveries ranging from 96.17% to 101.81%.

Three undescribed chromanones (1–3) and two known chromanones (4 and 5) were isolated from the culture of endophytic fungus Phomopsis CGMCC No. 5416 from the stems of Achyranthes bidentata. Their structures were determined by spectroscopic analysis. Compounds 1 and 2 showed inhibitory activities against HIV-1 with IC50 values of 20.4 and 32.5 μg ml−1, respectively. Compounds 1–3 displayed moderate cytotoxicity with CC50 values of 36.5–79.3 μg ml−1 against A549, MDA-MB-231, and PANC-1 cell lines. Moreover, compound 3 can induce the early apoptosis of PANC-1 cancer cells with the apoptosis rate of 10.52%.

Electrochemical sensing is a promising analytic method with its advantages, such as low cost, fast response, simple operation, high accuracy, low detection limit and so on. With the rapid development of electroanalysis, various modified electrodes were synthesized for constructing different kinds of electrochemical sensors on purpose. Macrocyclic compounds with their superior supramolecular recognition properties have aroused the research interest, as they can be used as modifiers for enhancing the sensitivity and selectivity of electrodes. All five classic macrocyclic compounds, which are crown ethers, cyclodextrins, calixarenes, cucurbiturils, and pillararenes, have been employed as receptors for electrochemical sensors, and these macrocycles have led to a wilder detection range, a lower detection limit, and superior ability of anti-interferences against coexisting ions or molecules. The macrocycles modified electrodes have shown greater sensitivity and selectivity in detection. Therefore, this review focuses on the results of the studies published in recent 8 years on macrocycles improved electrochemical sensing. In this review, the recent development of functionalization of macrocyclic compounds including crown ethers, cyclodextrins, calixarenes, cucurbiturils, pillararenes, on electrochemical sensors has been summarized.

Fluorescent chemosensors based on a new macrocyclic compound, multifarene[2,2], with modification by triazole-linked pyrene or anthracene were synthesized. These macrocyclic sensors exhibited high affinity and selectivity toward Ag+ over other metal ions, with ratiometric or enhanced response of their fluorescence emissions depending upon the substituent species for coordination to Ag+, and an unexpected response to a concentration threshold of the metal cations was discovered. The experimental evidences of fluorescence spectra, 1H NMR titration, IR spectra, and high-resolution mass spectra suggested the coordination behaviors of the sensors with Ag+, that is, the 1:1 complexes were formed with moderate association constants of about 105 L·mol−1, and the sulfur atoms on macrocyclic ligand should affinite to the metal cations. Energy-minimized structures and frontier orbitals were estimated by quantum chemical calculations with a view to rationalizing the fluorescence response of the multifarene[2,2] sensors upon binding to Ag+.

Cortex Moutan (Paeonia suffruticosa Andr.) is a common traditional Chinese medicine and has been widely used in clinic for 2000 years in China. As sources for this crude drug are always mixed with other species, many cultivars on herbal market may lead to quality instability. Multi-component quantitative analysis is an efficient method to reflect chemical profiles of herb medicine and is always taken as the main method for quality evaluation. So, the aim of this work is to develop analytical method to quantify paeonol, paeoniflorin, gallic acid, oxypaeoniflorin, benzoylpaeoniflorin and paeonolide in Cortex Moutan (CM) to evaluate the chemical qualities of CM from different species or cultivars. Besides, we also study the intestinal absorption characteristics of paeonol and paeoniflorin for further pharmacological evaluation. In the present study, all of the standard markers were performed on an Ecosil C18 (250 mm × 4.6 mm, 5 μM, Lubex Co., Guangzhou, China) with linear gradient elution of 0.2% formic acid water and acetonitrile. The proposed method was applied to analyze 50 batches of samples with acceptable linearity (R2, 0.9995 - 0.9999), precisions (RSD, 0.47% - 2.08%), repeatability (RSD, 039% - 2.63%), stability (RSD, 0.52% - 2.45%), and recovery (RSD, 0.72% - 3.03%) of the six compounds. Furthermore, the Hierarchical Cluster Analysis was applied to classify the 50 samples based on contents of the six compound markers. The results obtained from multi-component quantification of CM clearly indicated that CM originated from P. suffruticosa and P. ostii presented different chemical properties, and that samples from the two materials could be gathered into one branch, respectively, while CM sourced from cultivars of P. suffruticosa showed great variety on chemical quality. The results from Hierarchical Cluster Analysis implied that the established method could be used as a powerful tool for the quality evaluation of CM. The intestinal absorption study indicated that the intestinal absorption activities for paeoniflorin and paeonol showed an increasing absorption with time. Paeonol had lower absorption rate (6.69% - 15.93%) than that of paeoniflorin (19.0% - 30.70%). As a result, the established method is suitable for the quality evaluation of CM. The results of intestinal absorption characteristics of paeonol and paeoniflorin offer an insight for pharmacological evaluation and clinical efficacy research of CM.

Background Our previous study showed that the ribosomal protein L21 (RPL21) may play an important role in the development and survival of pancreatic cancer. In this article, RNA interference (RNAi) experiments were performed with RPL21-specific small interfering RNA (siRNA) to elucidate the mechanism by which RPL21 controls PC PANC-1 and BxPC-3 cell proliferation. Methods In the present study, PANC-1, BxPC-3 cells, and BALB/c nude mice were used to investigate antitumor effect and mechanism by which RPL21 controls cell proliferation and apoptosis in vitro and in vivo. The effects of RPL21 knockdown on PANC-1 and BxPC-3 cell proliferation, cell cycle and cell apoptosis in vitro were determined using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assays and flow cytometry assay. The mechanism of RPL21 regulating cell proliferation was investigated using transcriptome sequencing analysis and luciferase reporter assay. The effects of RPL21 knockdown on PANC-1 and BxPC-3 cell proliferation in vivo were determined using BALB/c nude mice tumor model. Results In PANC-1 and BxPC-3 cells, the knockdown of RPL21 expression with corresponding siRNA suppressed cell proliferation in vitro and in vivo, inhibited DNA replication, and induced arrests in the G1 phase of the cell cycle. Further results showed that the mini-chromosome maintenance (MCM) protein family (MCM2-7), CCND1 and CCNE1 were down-regulated significantly in PANC-1 and BxPC-3 cells after transfected with RPL21 siRNA, which suggests that the suppression of DNA replication is due to the reduced expression of MCM2-7 family, and the induction of G1 arrest is correlated with the inhibition of CCND1 and CCNE1. Luciferase reporter assay showed that RPL21 controls the DNA replication and G1-S phase progression possibly through the regulation of E2F1 transcription factor in PC cells. Moreover, RPL21 siRNA showed an apoptosis-inducing effect only in BxPC-3 and PANC-1 cells but not in normal HPDE6-C7 cells. The increase of caspase-8 activities and the loss of mitochondrial membrane potential after RPL21 silencing indicates that the RPL21 gene may be involved in caspase-8-related mitochondrial apoptosis. Conclusion Our findings suggest that siRNA against the RPL21 gene possesses a potential anti-cancer activity for PC cells by inhibiting their proliferation and DNA replication, as well as inducing cell cycle G1 arrest and cell apoptosis.

Three undescribed azaphilones, phomopsones A-C (1–3) and two known azaphilones (4–5) were isolated from the culture of endophytic fungus Phomopsis sp. CGMCC No.5416 from the stems of Achyranthes bidentata. Their structures were determined by spectroscopic analysis (HRESIMS, 1D and 2D NMR), and the absolute configurations were determined by CD spectroscopy. Compounds 2 and 3 showed significant inhibitory activities against HIV-1 with against HIV-1 with IC50 values of 7.6 and 0.5 μmol/L, respectively. Compounds 2 and 3 also displayed moderate cytotoxicity with CC50 values of 3.2–303 μmol/L against A549, MDA-MB-231 and PANC-1 cell lines. Moreover, compound 3 can induce the early apoptosis of PANC-1 cancer cells with the apoptosis rate of 28.54%.

Backgroud Leptospira interrogans is the major causative agent of leptospirosis, a worldwide zoonotic disease. Hemorrhage is a typical pathological feature of leptospirosis. Binding of von Willebrand factor (vWF) to platelet glycoprotein-Ibα (GPIbα) is a crucial step in initiation of platelet aggregation. The products of L. interrogans vwa-I and vwa-II genes contain vWF-A domains, but their ability to induce hemorrhage has not been determined. Methods Human (Hu)-platelet- and Hu-GPIbα-binding abilities of the recombinant proteins expressed by L. interrogans strain Lai vwa-I and vwa-II genes (rLep-vWA-I and rLep-vWA-II) were detected by flowcytometry, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Hu-platelet aggregation and its signaling kinases and active components were detected by lumiaggregometry, Western analysis, spectrophotometry and confocal microscopy. Hu-GPIbα-binding sites in rLep-vWA-I and rLep-vWA-II were identified by SPR/ITC measurements. Findings Both rLep-vWA-I and rLep-vWA-II were able to bind to Hu-platelets and inhibit rHu-vWF/ristocetin-induced Hu-platelet aggregation, but Hu-GPIbα-IgG, rLep-vWA-I-IgG and rLep-vWA-II-IgG blocked this binding or inhibition. SPR and ITC revealed a tight interaction between Hu-GPIbα and rLep-vWA-I/rLep-vWA-II with KD values of 3.87 × 10−7-8.65 × 10−8 M. Hu-GPIbα-binding of rL-vWA-I/rL-vWA-II neither activated the PI3K/AKT-ERK and PLC/PKC kinases nor affected the NO, cGMP, ADP, Ca2+ and TXA2 levels in Hu-platelets. G13/R36/G47 in Lep-vWA-I and G76/Q126 in Lep-vWA-II were confirmed as the Hu-GPIbα-binding sites. Injection of rLep-vWA-I or rLep-vWA-II in mice resulted in diffuse pulmonary and focal renal hemorrhage but this hemorrhage was blocked by rLep-vWA-I-IgG or rLep-vWA-II-IgG. Interpretation The products of L. interrogans vwa-I and vwa-II genes induce hemorrhage by competitive inhibition of vWF-mediated Hu-platelet aggregation.

Fluorescence spectroscopy, 1H NMR spectroscopy and quantum chemical calculations were used to investigate the interactions of benzo[6]urils with polycyclic aromatic hydrocarbons acting as the guest molecules. The fluorescence emission of the host was decreased upon the addition of an increasing amount of the guest molecules, providing an association constant in the range of 8.0 × 102–7.5 × 104 L mol−1 obtained via non-linear curve fitting, and the formation of host–guest complexes in a 1 : 1 ratio was confirmed using Job's plot analysis. In addition, the 1H NMR spectra also supported the formation of the interaction complexes with changes in the chemical shifts of the aromatic protons in the host molecules being observed in the presence of the guest molecules. The calculation results provided the structures of the encapsulation complexes with the driving force attributed to the formation of hydrogen bonds between the benzo[6]urils host and the guest molecules. The unique property of luminescence with electrochemical reaction was discovered in methyl-substituted benzo[6]uril, which has great potential as a new type of electrochemiluminescent material.

N6-methyladenosine (m6A) is the most thoroughly studied type of internal RNA modification, as this epigenetic modification is the most abundant in eukaryotic RNAs to date. This modification occurs in various types of RNAs and plays significant roles in dominant RNA-related processes, such as translation, splicing, export and degradation. These processes are catalyzed by three types of prominent enzymes: writers, erasers and readers. Increasing evidence has shown that m6A modification is vital for the regulation of gene expression, carcinogenesis, tumor progression and other abnormal changes, and recent studies have shown that m6A is important in the development of hepatocellular carcinoma (HCC). Herein, we summarize the nature and regulatory mechanisms of m6A modification, including its role in the pathogenesis of HCC and related chronic liver diseases. We also highlight the clinical significance and future strategies involving RNA m6A modifications in HCC.

X-ray diffraction (XRD) reciprocal space mappings (RSMs) and transmission electron microscopy (TEM) were applied to structurally characterize InGaN multi-quantum-well (MQW) alloys with a novel structure which were epi-grown successively on a rough thick n-InGaN layer with {1 0 1 ¯ m} (2 1 ¯ m〉 modulation direction, was observed by TEM and unconventional shift of satellite peaks in reciprocal space took place in XRD (1 0 1 ¯ 5) RSM. The two scarce phenomena are attributed to the special morphology of V-MQWs.

Incubation and shape transition are considered as two essential processes for nucleating of self-assembly InGaN nanocolumns (NCs) in traditional way. We propose a new approach for nuclei forming directly by in-situ annealing and ion irradiating the InGaN template during growing process. The nanoislands, considered as the nuclei of NCs, were formed by a combinational effect of thermal and ion etching (TIE), which made the gaps of the V-pits deeper and wider. On account of the decomposition of InGaN during TIE process, more nitride-rich amorphous alloys would intent to accumulate in the corroded V-pits. The amorphous alloys played a key role to promote the following growth from 2D regime into Volmer-Weber growth regime so that the NC morphology took place, rather than a compact film. As growth continued, the subsequently epitaxial InGaN alloys on the annealed NC nuclei were suffered in biaxial compressive stress for losing part of indium content from the NC nuclei during the TIE process. Strain relaxation, accompanied by thread dislocations, came up and made the lattice planes misoriented, which prevented the NCs from coalescence into a compact film at later period of growing.

X-ray diffraction (XRD) reciprocal space mappings (RSM) were applied to structurally characterize InGaN multi-quantum-wells alloys with V-shape morphology (V-MQWs), epi-grown successively on the rough thick n-InGaN layer by plasma assisted molecular beam epitaxy on c -plane sapphire. In asymmetric (105) RSM, all reciprocal lattice points (RLPs) of satellite peaks have obvious shift to both sides along axis Q x , but the RLP of the zero-order peak diffracted from MQWs locates at the pseudomorphic line, aligning with the n-InGaN layer diffraction peak (substrate peak) along axis Q y . Unlike the shift of satellite peaks caused by partial strain relaxation of MQWs in asymmetric RSM, the abnormal shift in our sample is aroused by the special profiles of interfaces of V-MQWs. According to the x-ray reflectivity of the interfaces of MQWs, the quasi-symmetric V-shape MQWs can be divided into the so-called “high reflection coefficient (HRC)” area and the “high transmission coefficient (HTC)” area. In kinematics of XRD, the satellite peaks from MQWs can be attributed to the diffraction of reflected x-ray by interfaces of MQWs. In that case, the satellite peaks were modified by the interfaces of V-MQWs so that RLPs of satellite peak were contributed by the diffraction of interfaces of MQWs in HRC area, rather than in the HTC area. The zero-order peak from MQWs was still determined by the diffraction from lattice planes both within the HRC and HTC areas.

Pristinamycin, produced by Streptomyces pristinaespiralis, which is a streptogramin-like antibiotic consisting of two chemically unrelated components: pristinamycin I (PI) and pristinamycin II (PII), shows potent activity against many antibiotic-resistant pathogens. However, so far pristinamycin production titers are still quite low, particularly those of PI. In this study, we constructed a PI single component producing strain by deleting the PII biosynthetic genes (snaE1 and snaE2). Then, two metabolic engineering approaches, including deletion of the repressor gene papR3 and chromosomal integration of an extra copy of the PI biosynthetic gene cluster (BGC), were employed to improve PI production. The final engineered strain ΔPIIΔpapR3/PI produced a maximum PI level of 132 mg/L, with an approximately 2.4-fold higher than that of the parental strain S. pristinaespiralis HCCB10218. Considering that the PI biosynthetic genes are clustered in two main regions in the 210 kb “supercluster” containing the PI and PII biosynthetic genes as well as a cryptic polyketide BGC, these two regions were cloned separately and then were successfully assembled into the PI BGC by the transformation-associated recombination (TAR) system. Collectively, the metabolic engineering approaches employed is very efficient for strain improvement in order to enhance PI titer.

With a facile preparation for graphitic carbon nitride quantum dots (g-C3N4 QDs), an ultrasensitive photoelectrochemical (PEC) sensor was developed with the supramolecular affinity of chiral multifarene[3,2,1] (CMF) to a hormone drug, thyroxine (T4), for efficient identification of thyroxine enantiomers. In the principle that g-C3N4 QDs was employed to achieve the photocurrent response and the macrocyclic compound served as the supramolecular enantiorecognition for thyroxine, the photoelectrochemical electrode was constructed by layer-by-layer assembly of g-C3N4 QDs and CMF on the surface of ITO (ITO-g-C3N4-CMF QDs). The proposed PEC sensor produced the limits of detection low to 67 pM towards L-T4 and 85 pM towards D-T4 in a concentration range from 0.1 nM to 10 nM, which was superior to the values in pioneering reports with colorimetric or electrochemical methods. With good stability, reproducibility, repeatability anti-interference ability, and acceptable recoveries, the proposed PEC sensor was employed for quantitative determination of L/D-T4 in water, human serum and commercial tablet.

A novel chiral sensor was developed to produce the distinguishing response to the enantiomers of tyrosine (Tyr), with high sensitivity and selectivity. The electrochemical sensor was modified by the inorganic-organic nanohybrid material with the functionalization of reduced graphene oxide (rGO) to be the amplifier and a chiral hetero-multifarene[3,2,1] (CHMF[3,2,1]) as the chiral receptor. The as-prepared rGO-CHMF was characterized by transmission electron microscopy (TEM), atomic force microscope (AFM), infrared spectroscopy (IR), thermogravimetric analysis (TGA), Raman spectroscopy and electrochemical methods. It was observed that the composites exhibited different binding ability for Tyr enantiomers. The proposed sensor presented significant difference with peak potential separation value (ΔEp = 70 mV) and the ratio of peak current (IL-Tyr/ID-Tyr = 1.58) for Tyr enantiomers by differential pulse voltammetry. In addition, the peak currents increased linearly with the concentration of Tyr enantiomers in the concentration range 0.1–10 μM with detection limits of 78 nM and 83 nM for l -Tyr and d -Tyr (S/N = 3), respectively. It also exhibited the ability to determine the percentage of one Tyr enantiomer in the racemic mixture. Moreover, the selectivity, reproducibility, and stability of the chiral sensor were investigated to give satisfactory results. The above discoveries offered an alternative technology for chiral recognition with electrochemical response to actualize a real-time and quantitative determination.

The progress of chiral electroorganic chemistry, an emerging field in asymmetric organic synthesis and electrocatalysis, is summarized in this work. In recent years, with the intensive research of asymmetric organic synthesis and the rapid development of electrocatalytic organic synthesis, asymmetric electrochemical reactions have attracted the attention of researchers. The use of electrochemical methods is propitious to the controllability of product, and greenness, sustainability, repeatability of the process to synthesize enantiomers. From the organic chemical point of view, this review highlighted the reaction types with various electrochemical strategies, that is, the applications of electroreduction, electrooxidation, and electrochemical chiral resolution, respectively, for classified asymmetric electrosynthesis, and a longitudinal discussion is also conducted in each type of electroorganic reactions in different enantioselective strategies. This summary provides deep and systemic insights on the application of electrochemical methods in asymmetric organic synthesis.

Two-dimensional (2D)molybdenum disulfide (MoS2) promiseda widerange of potential applications. Here, we report the transport investigations on the MoS2 from Armchair (AC) and Zigzag (ZZ) directions with different kinds of leads. The conductance of 2H phase MoS2 depended on the transport directions and lead types (2H phase or 1T phase). System with 1T phase MoS2 as lead can impressively improve the transport properties compared with the 2H phase lead. Moreover, for the system with metal lead, enhanced conductance can be observed, which contrast to the experi- ment measurements. Further investigate indicated that the conductance is sensitively rely on the distance between metal lead and 2D material. The present theoretical re- sults suggested the lead material and interface details are both important for MoS2 transport exploration, which can provide vital insights into the other 2D hybrid mate- rials.

Fluorescence and electrochemical response of multifarene[3,3](S) to serotonin hydrochloride and its quantitative measurement by hybridization on the surface of reduced graphene oxide were investigated. The fluorescence titration suggested the formation of host–guest complex in a radio of 1:1, and the moderate association constants of (1.7 ± 0.3) × 104 M (in DMSO) and (2.7 ± 0.2) × 104 M (in water) were obtained by non-linear curve fitting, which implied the supramolecular interaction could be irrelevant to the species of solvents. Furthermore, the hybridization of multifarene[3,3](S) with reduced graphene oxide improved the response to serotonin hydrochloride in both fluorescence and voltammetry, which was employed to realize the quantitative analysis for the drug, and a low limit of detection of 3.9 × 10−7 M was found for determination in the real simple of human serum.

A series of AlN/GaN heterostructures were grown on 150 mm Si substrates by metal organic chemical vapor deposition (MOCVD). Different cap layer structures, including gallium nitride (GaN) and silicon nitride (SiNx), were used to passivate the heterostructure surface. A 3.5 nm thick SiNx cap is able to maintain the two dimensional electron gas (2DEG) stability in a long period. An AlN/GaN heterostructure with a 4.5 nm thick AlN barrier exhibits the best 2DEG properties, in terms of sheet resistance, carrier mobility and stability. The carrier mobility of the 2DEG can be enhanced by a combination of SiNx and GaN cap layers to over 1400 cm2/Vs.

The composites of benzo[6]uril-hybridized graphene oxide were realized with the full characterization of atomic force microscopy (AFM), Infrared spectroscopy (IR), and Raman spectroscopy, which exhibited dramatical improvement of the fluorescence response to the supramolecular interactions of umbelliferones with the macrocyclic compounds to produce the ternary supramolecular hybrid materials, and the host-guest interactions were evidenced with 1H NMR, fluorescence titrations, and molecular simulations to confirm the encapsulation of the umbelliferone guests within the cavities of the macrocyclic hosts. The supramolecular materials were applied for quantitative determination for diquat to give the limits of detection of 3.4 × 10−7 mol L−1 and 5.0 × 10−7 mol L−1, respectively, with high selectivity in coexistence of other bipyridyl interferences including 2,2′-bipyridine, 4,4′-bipyridine, and methyl viologen in aqueous solutions.

The root bark of tree peony (Paeonia suffruticosa Andr.), also called Coetex Moutan (CM), is a traditional Chinese medicine. The medicinal plant is also well known for its beautiful flowers with hundreds of cultivars. CM from different cultivars or grown in various geographic areas are significantly different in quality and chemical properties. So the aim of this study is to develop specific SSRs by transcriptome analysis to distinguish CM samples from different sources and quantify the contents of paeonol and paeoniflorin to evaluate its chemical qualities. Totally, 6654 SSR markers were developed in the coding regions by transcriptome. 10 pairs of SSRs were found to be consistently polymorphic when applied in all fifty individuals collected from three typical producing areas (Chongqing, Henan, and Anhui province). These CM individuals were originated from two medicinal cultivars of P. suffruticosa and Paeonia ostii T. Hong et J. X. Zhang and horticultural varieties. The genetic results indicated that fifty samples could be clearly divided into three clusters based on genetic distance, in which samples from the same species all gathered together without being affected by geographical origins. The accumulations of two main chemical markers showed great variation among tree peony species or cultivars, in which production area was found as another important factor for this variation except the origin. As a result, the chemical profiles combined with the genetic fingerprint are proved to be effective and could precisely authenticate species and discriminate quality of CM.

The chem-sensors, based on the triazole-CH2-anthracene-functionalized multifarene[2,2] were successfully synthesized, which could efficiently and rapidly detect 2,4,6-trinitrophenol (TNP). The high specificities of the proposed macrocyclic sensors were achieved by selective response for TNP in the existence of other competing phenolic compounds, and the limits of detection in ∼10−8 mol/L range were produced to confirm the high sensitivities of the chem-sensors, which could be attributed to the mechanism of electron and resonance energy transfer processes in the complexes with the supramolecular interactions. 1H NMR titration analysis revealed the actual binding position should be the triazole rings of sensors with the hydroxyl group on TNP to offer a hydrogen bonding. The extraordinary sensing properties endued the compounds as sensitive fluorometric chem-sensors for the potential application of TNP detection.

Background Cordyceps sinensis has been used for centuries in China as one of the most valued herbal medicine and tonic food. Paecilomyces hepiali, a fungal strain isolated from natural C. sinensis, has been used widely as a substitute of C. sinensis in medicine and health food. P. hepiali has been reported to have various pharmaceutical benefits, including triglyceride-lowing activity. However, its effects on triglyceride metabolism in adipocytes remain unknown. The purpose of the present study was to evaluate the effect of P. hepiali mycelia on adipocyte lipolysis and to clarify the underlying mechanisms. Methods The fully differentiated 3T3-L1 adipocytes were treated with methanol extract of Paecilomyces hepiali mycelia (PHME). Contents of glycerol released into the culture medium and intracellular triglyceride were measured as indices of lipolysis using glycerol assay kit and Oil red O staining, respectively. Then, effects of PHME on the main lipases or kinases involved in lipolysis regulation were investigated. Protein expression of adipose triglyceride lipase (ATGL) and perilipin, as well as phosphorylation of hormone-sensitive lipase (HSL), AMP-activated protein kinase (AMPK), and mitogen-activated protein kinases (MAPKs) were determined by western blotting. Moreover, nucleosides, important constituents of PHME, were analyzed using high performance liquid chromatography (HPLC). Results Treatment with PHME led to a significant increase in glycerol release thereby reduced intracellular triglyceride accumulation in fully differentiated adipocytes. PHME upregulated protein kinase (PK) A-mediated phosphorylation of HSL at serine residues of 563 and 660. Meanwhile, PHME treatment also upregulated phosphorylation of extracellular signal-regulated kinase (ERK), and downregulated the protein level of perilipin. Pretreatment with the PKA inhibitor, H89, blunted the PHME-induced lipolysis and the phosphorylation of HSL (Ser 563 and 660). Moreover, pretreatment with ERK inhibitor, PD98059, weakened the PHME-caused glycerol release and downregulation of perilipin expression. HPLC analysis indicated there were adenosine, cordycepin, uridine and vernine in PHME. Conclusions Our results showed that PHME significantly induced lipolysis in 3T3-L1 adipocytes, which is mainly mediated by activation of HSL through PKA pathway and by downregulation of perilipin through activation of ERK pathway. Electronic supplementary material The online version of this article (10.1186/s12906-018-2389-0) contains supplementary material, which is available to authorized users.

Two novel quinomycins I (1) and J (3) were discovered by UPLC-MS, then the two novel compounds and five known quinomycins A(2), B(4), E(5), C(6) and monosulfoxide quinomycin (7) were isolated from the culture broth of Streptomyces sp. HCCB11876. The structures of these compounds were elucidated through MS and NMR spectroscopic analysis. Compounds 1-7 showed significant antibacterial and cytotoxic activities. The structure-activity relationship indicated that sulfoxide group in N-methylcysteine of quinomycins (1, 3 and 7) would significantly decrease the antibacterial and cytotoxic activities. Moreover, the antibacterial and cytotoxic activities were decreased with the increase of carbon chain in amino-acid residues.

Apoptosis plays a critical role in many biological processes and the etiology of various diseases of the immune system. The study of apoptosis would allow both improving the diagnosis of certain diseases and serving as a target of drug screening. In this paper, we developed a sensitive assay of single-cell apoptosis using semiconductor quantum dots (QDs) as fluorescent-labeling probes. The principle of this assay is based on the detection of phosphatidylserine (PS) exposed on the plasma membrane during the drug-induced apoptosis. The QD-labeled annexin V (AV) was prepared to specifically target PS on the membrane of apoptotic cells, and PS was detected by fluorescent imaging, flow cytometer, and single-molecule fluorescence correlation spectroscopy (FCS). We developed the procedures for conjugation of QDs to AV and for purification of their conjugates by gel chromatography. The obtained conjugates were characterized by FCS, capillary electrophoresis, and zeta potential analyzer. We studied the nonspecific adsorption of cells to different surface-modified QDs and found that the nonspecific adsorption effects were significantly reduced by modification of QDs with polyethylene glycol in the detection of apoptosis. In this assay, the results obtained by flow cytometry were consistent with the commercial test kit. Furthermore, a home-built single-molecule FCS system was developed for in situ study the drug-induced apoptosis. We observed the significant change in the diffusion coefficients of QDs on cells during the progress of cell apoptosis. Compared with conventional methods, the fluorescent methods represented here possess high sensitivity because of the use of high photo stability and brightness QDs as labeling probes and provide the temp-spatial information on a single apoptotic cell.

Actinomycetes have evolved in the process of ecological interactions between animals, plants and microorganisms in the environment to produce new classes of secondary metabolites with novel structures,1, 2, 3 of which polyene macrolides are very interesting bioactive compounds with a wide range of biological activities and subject to a relatively low incidence of resistance.4, 5 Many of these molecules have been successfully isolated and turned into useful drugs and other organic chemicals. In our study aimed at the discovering of novel antifungals, the soil actinomycete, Streptomyces lavenduligriseus, was found to produce strong antifungal components. Bioactivity-guided isolation and purification yielded filipin III 1 and three novel polyene macrolides, compound 2, 3 and 4 (Figure 1). Details of the isolation, structure elucidation and the antifungal activities of these compounds are presented below.

The objective of this work was to identify the main allergenic proteins and to assess the influence of high hydrostatic pressure on the potential allergenicity of high hydrostatic pressure pineapple juice. Fresh pineapple juice was treated with different pressures and the allergenic proteins were extracted and analyzed by sodium dodecyl sulfate polyacrylamide gel electropheresis, Western bloting and liquid chromatography-tandem mass spectrometry. The main allergenic proteins were detected as 24-kDa and 14-kDa bands by serum of pineapple-allergic patients. liquid chromatography-tandem mass spectrometry analysis of these bands showed that they actually consisted of a mixture of several isotypes of cysteine proteinases. Among these, bromelain (Ananas comosus) is a known allergen named Ana c 2 and it is highly homologous to other cysteine proteinases. Enzyme-linked immunosorbent assay assay of high hydrostatic pressure pineapple juice carried out at ambient temperature (18–22°C) showed that the higher the pre...

Toll-like receptor 4 (TLR4)-mediated signaling plays a critical role in sepsis-induced acute lung injury (ALI). LYRM03 (3-amino-2-hydroxy-4-phenyl-valyl-isoleucine) is a novel derivative of ubenimex, a widely used antineoplastic medicine. We previously found that LYRM03 has anti-inflammatory effects in cecal ligation puncture mouse model. In this study we determined whether LYRM03 attenuated LPS-induced ALI in mice. LPS-induced ALI mouse model was established by challenging the mice with intratracheal injection of LPS (5 mg/kg), which was subsequently treated with LYRM03 (10 mg/kg, ip). LYRM03 administration significantly alleviated LPS-induced lung edema, inflammatory cell (neutrophils and macrophages) infiltration and myeloperoxidase (MPO) activity, decreased pro-inflammatory and chemotactic cytokine (TNF-α, IL-6, IL-1β, MIP-2) generation and reduced iNOS and COX-2 expression in the lung tissues. In cultured mouse alveolar macrophages in vitro, pretreatment with LYRM03 (100 μmol/L) suppressed LPS-induced macrophage activation by reducing Myd88 expression, increasing IκB stability and inhibiting p38 phosphorylation. These results suggest that LYRM03 effectively attenuates LPS-induced ALI by inhibiting the expression of pro-inflammatory mediators and Myd88-dependent TLR4 signaling pathways in alveolar macrophages. LYRM03 may serve as a potential treatment for sepsis-mediated lung injuries.

To obtain functional expression of a heterologous multifunctional carotene synthase containing phytoene synthase, phytoene dehydrogenase, and lycopene β-cyclase activities encoded by carS from Schizochytrium sp. in order to allow Yarrowia lipolytica to produce β-carotene. To increase the integration efficiency of a 3.8 kb carS under the control of P GPD promoter with a 2 kb selection marker, ura3, along with a geranylgeranyl diphosphate synthase (GGS1) expression cassette (~10 kb in total), was inserted into the Y. lipolytica chromosome, and the DNA assembler method was combined with double chromosomal deletions of ku70 and ku80. This method resulted in a 13.4-fold increase in integration efficiency compared with the original method, reaching 63% (10/16). The resulting recombinant Y. lipolytica produced 0.41 mg β-carotene per g dry cell weight, while the wild type did not produce any indicating the functionality of the multifunctional carotene synthase in Y. lipolytica. Expression of GGS1 and a multifunctional carotene synthase from Schizochytrium sp. in Y. lipolytica led to β-carotene production. DNA assembler efficiency was greatly increased by the deletion of ku70 and ku80, which resulted in decreased in vivo nonhomologous end-joining (NHEJ) in Y. lipolytica.

There are up to seven regulatory genes in the pristinamycin biosynthetic gene cluster ofStreptomyces pristinaespiralis, which infers a complicated regulation mechanism for pristinamycin production. In this study, we revealed that PapR6, a putative atypical response regulator, acts as a pathway-specific activator of pristinamycin II (PII) biosynthesis. Deletion of thepapR6gene resulted in significantly reduced PII production, and its overexpression led to increased PII formation, compared to that of the parental strain HCCB 10218. However, eitherpapR6deletion or overexpression had very little effect on pristinamycin I (PI) biosynthesis. Electrophoretic mobility shift assays (EMSAs) demonstrated that PapR6 bound specifically to the upstream region ofsnaF, the first gene of thesnaFE1E2GHIJKoperon, which is likely responsible for providing the precursor isobutyryl-coenzyme A (isobutyryl-CoA) and the intermediate C11αβ-unsaturated thioester for PII biosynthesis. A signature PapR6-binding motif comprising two 4-nucleotide (nt) inverted repeat sequences (5′-GAGG-4 nt-CCTC-3′) was identified. Transcriptional analysis showed that inactivation of thepapR6gene led to markedly decreased expression ofsnaFE1E2GHIJK. Furthermore, we found that a mutant (snaFmu) with base substitutions in the identified PapR6-binding sequence in the genome exhibited the same phenotype as that of the ΔpapR6strain. Therefore, it may be concluded that pathway-specific regulation of PapR6 in PII biosynthesis is possibly exerted via controlling the provision of isobutyryl-CoA as well as the intermediate C11αβ-unsaturated thioester.

The A21978C family of compounds includes precursors of daptomycin, an important antibiotic for the treatment of diseases infected by Gram-positive resistant bacteria. Focusing on these valuable compounds, the differences in metabolites obtained with or without pH control in their producing strain Streptomyces parvus HCCB10043 were investigated by comparative metabolomics analysis based on UPLC-TOF-MS technology. According to principal component analysis, there were fourteen biomarker compounds selected under the two pH culture conditions. The ten known compounds were divided into two types: a glycoside family participating in the primary metabolism (daidzein, glycitein, genistein, and soyasaponin Bb) and a peptide family of secondary metabolites (valistatin, bestatin, 3-amino-2-hydroxy-4-phenylbutanoylvalylisoleucine, and arylomycins A2, A4, and A5). Through orthogonal partial least squares-discriminant analysis, three compounds, soyasaponin Bb and arylomycins A2 and A4 were identified as the most relevan...

A novel dihydronaphthalenone, phomonaphthalenone A (1) was isolated from solid cultures of the endophytic fungus Phomopsis sp. HCCB04730, together with six known naphthoquinones (2–7). The structure of 1 was elucidated through spectroscopic and X-ray crystallographic analysis. Cytotoxic and anti-HIV activities of compounds 1–7 were also investigated. All compounds exhibited cytotoxic and anti-HIV activities. Compounds 1 and 7 showed moderate anti-HIV activities with IC50 values of 11.6 and 9.4 μg/mL, and relatively low cytotoxicity. Compounds 2, 4, and 5 showed significant cytotoxicity with IC50 values less than 4.7 μg/mL against A549, MDA-MB-231 and PANC-1 cell lines.

Analysis of the Amycolatopsis orientalis genome revealed that two genes, hemA1 and hemA2, belonging to divergent pathways, were involved in the biosynthesis of 5-aminolevulinic acid. The roles of hemA1 and hemA2 were elucidated via genetic manipulation and metabolite analysis. The disruption of hemA1, encoding the glutamyl-tRNAGlu reductase of the C5 pathway, was essential for cell growth and is used for heme synthesis. Overexpression of hemA1 resulted in elevated vancomycin and ECO-0501 production in Amycolatopsis orientalis, and it was also effective in increasing the production of daptomycin and natamycin in other Streptomycetes. The disruption of hemA2 indicated that it encodes the 5-aminolevulinic acid synthase of the Shemin pathway, serving as a key enzyme for the synthesis of the precursor aminohydroxycyclopentenone unit of ECO-0501. However, hemA2 disruption could not be complemented by the addition of 5-aminolevulinic acid or by the expression of hemA2 outside of the ECO-0501 gene cluster. The synthesis of ECO-0501 was only restored by the insertion of hemA2 at its original locus. The hemA2 gene could partly complement the hemA1 deficiency. Overexpression of hemA1, a key gene from the heme biosynthetic pathway, is proposed here as a new approach to improve the production of secondary metabolites in bacteria, whereas hemA2 plays different roles depending on its pattern of expression.

β-Carotene is a terpenoid molecule with high hydrophobicity that is often used as an additive in foods and feed. Previous work has demonstrated the heterologous biosynthesis of β-carotene from an intrinsic high flux of acetyl-CoA in 12 steps through 11 genes in Yarrowia lipolytica. Here, an efficient biosynthetic pathway capable of producing 100-fold more β-carotene than the baseline construct was generated using strong promoters and multiple gene copies for each of the 12 steps. Using fed-batch fermentation with an optimized medium, the engineered pathway could produce 4g/L β-carotene, which was stored in lipid droplets within engineered Y. lipolytica cells. Expansion of these cells for squalene production also demonstrated that Y. lipolytica could be an industrially relevant platform for hydrophobic terpenoid production.

Analysis of the Amycolatopsis orientalis HCCB10007 genome revealed new gene clusters involved in natural product biosynthesis that were not associated with the production of known compounds. Halogenases are a type of tailoring enzymes that are usually found within these secondary gene clusters. In this study, we identified an indole-type halometabolite 6-chrolo-1H-indole-3-carboxamide, named LYXLF2, by whole genome mining and metabolic profiling of a flavin-dependent halogenase mutant. LYXLF2 is a new plant growth-regulating compound that promotes root elongation. The results of this study demonstrated that the special gene knock-out/comparative metabolic profiling approach provides a powerful tool for the discovery of novel natural products by genome mining.

Arylomycins are type I signal peptidase inhibitors and have a potential as a new type of antibiotics. They were identified from the broth of Streptomyces sp. HCCB10043. The arylomycin biosynthetic gene cluster in this strain was identical to that in S. roseosporus. Within the gene cluster, aryC, encoding a P450 enzyme, was deduced to be responsible for biaryl bond formation in, the arylomycins. Inactivation of aryC abolished arylomycin production and led to the generation of two novel linear lipopentapeptides lacking the aryl-aryl linkage. These derivatives had lost their antibacterial activities against Staphylococcus epidermidis which is sensitive to arylomycins A2 and A4.

A novel phytotoxic nonenolide, (6S,7R,9R)-6,7-dihydroxy-9-propylnon-4-eno-9-lactone (1), was isolated from solid cultures of the endophytic fungus Phomopsis sp. HCCB03520, together with three known compounds, cytochalasin H (2), cytochalasin N (3), and epoxycytochalasin H (4). The structures of these compounds were elucidated through spectroscopic analysis, and the absolute configurations were determined by CD spectroscopy. Phytotoxic activities of compounds 1-4 were also investigated. Compound 1 showed phytotoxic activity on germination and radicle growth of Medicago sativa, Trifolium hybridum, and Buchloe dactyloides.

Titania nanotube (NT) arrays with a length of 550nm were fabricated on the flat titanium substrate by anodization. The microstructure was identified by scanning electron microscope. The composition has been investigated with X-ray photoelectron microscopy. It also showed that, as compared with the flat surface, the density of Ti-OH groups on the NT surface has been increased. However, according to the contact angle goniometer, the hydrophilicity of the NT surface becomes worse than that of the flat surface. In addition, surface roughness was investigated by non-contact atomic force microscope. It demonstrated that the nano-roughness of NT arrays has been increased. More important is the relationship between contact angle and roughness factor have been analyzed based on the modified Young’s equation. These results indicate that the anodized NT structures may have provided an optimal surface roughness for promoting the bioactivity.

A Type of Three-Dimensional Nano-Porous Film on Titanium Was Successfully Prepared by Alkali Treatment. the Microstructure, Contact Angle and Surface Energy of the Film Were Investigated Using Scanning Electron Microscopy (SEM) and Contact Angle Meter. the Biomineralization of the Nano-Porous Titanium Was Studied in Vitro by Soaking in Simulated Body Fluid (SBF). the Experiment Results Demonstrated that Bone-Like Apatite Could Be Induced on Nano-Porous Titanium Surface, and the Apatite Crystals on Nano-Porous Titanium Surface Were Superior in Number and Higher in Crystallinity to that on Titanium Chemically Polished.

Eight 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated in vitro vascular endothelial growth factor (VEGF) inhibitory activity with 2-methoxyestradiol (2-ME) as the reference compound. Most of the compounds showed potent VEGF inhibitory activity with EC50 values of micromolar or submicromolar range. Among them, the compounds 3 and 8 exhibited similar EC50 values and obviously better TI values compared with 2-ME.

According to the industrial operation data, modeling and flowsheeting to the full process of Sulfur-buring Sulfuric aid which contains 3 stages as following:Sulfur Burning, Conversion and Absorption were completed based on the ASPEN PLUS .Subsection Settings were applied on the thermodynamic method and choosing the suitable one for actual processes of each unit by analyzing the industrial system and process.Meanwhile,chemical reaction was built in the absorption tower. Sever important operating parameters were considered in the simulation. The simulation results showed that the model is reasonable,and could provide reference for the design ,renovation and optimization of the large-scale sulfur-buring sulfuric aic process.

Pyrenocines are better known as phytotoxic metabolites been found in Alternaria, Curvularia, Penicillium and Phomopsis strains. The class of compounds showed several biological activities, reportedly being phytotoxic, antifungal, cytotoxic, antitrypanosomal and antimalarial.1, 2, 3 Fungi of the genus Colletotrichum, a class of the widely distributed endophytic fungi, were reported as prolific producers of bioactive metabolites.4, 5, 6, 7 However, there are few reports on pyrenocines found in genus Colletotrichum. During our ongoing chemical investigations of endophytic fungi as sources of new cytotoxic natural products, the organic solvent extract of solid substrate fermentation culture of a Colletotrichum sp. HCCB03289 strain displayed cytotoxicity against cancer cell lines. Bioassay-guided fractionation of the extract led to the isolation of two novel pyrenocines N–O (1–2), and five known pyrenocines macommelin-9-acetate (3),8 pyrenocine A (4),9 pyrenocine B (5),9 pyrenocine E (6)10 and novae-zelandin A (7).11 Details of the isolation, structure elucidation and the cytotoxic activities of these compounds are presented here.