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Background Bupleurum chinense DC. is a widely used traditional Chinese medicinal plant. Saikosaponins are the major bioactive constituents of B. chinense, but relatively little is known about saikosaponin biosynthesis. In the present study, we performed an integrated analysis of metabolic composition and the expressed genes involved in saikosaponin biosynthetic pathways among four organs (the root, flower, stem, and leaf) of B. chinense to discover the genes related to the saikosaponin biosynthetic pathway. Results Transcript and metabolite profiles were generated through high-throughput RNA-sequencing (RNA-seq) data analysis and liquid chromatography tandem mass spectrometry, respectively. Evaluation of saikosaponin contents and transcriptional changes showed 152 strong correlations (P Conclusions Our results investigated the diversity of the saikosaponin triterpene biosynthetic pathway in the roots, stems, leaves and flowers of B. chinese by integrated transcriptomic and metabolomic analysis, implying that manipulation of P450s genes such as Bc95697 and Bc35434 might improve saikosaponin biosynthesis. This is a good candidate for the genetic improvement of this important medicinal plant.

Fundamental understanding of the nature of active sites in real-life water gas shift (WGS) catalysts that can convert CO and H2O into CO2 and H2 is crucial to engineer related catalysts performing under ambient conditions. Herein, we identified that the WGS reaction can be, in principle, catalyzed by rhodium-manganese oxide clusters Rh2MnO1,2- in the gas phase at room temperature. This is the first example of the construction of such a potential catalysis in cluster science because it is challenging to discover clusters that can abstract the oxygen from H2O and then supply the anchored oxygen to oxidize CO. The WGS reaction was characterized by mass spectrometry, photoelectron spectroscopy, and quantum-chemical calculations. The coordinated oxygen in Rh2MnO1,2- is paramount for the generation of an electron-rich Mn+-Rh- bond that is critical to capture and reduce H2O and giving rise to a polarized Rh+-Rh- bond that functions as the real redox center to drive the WGS reaction.

Low-carbon transformation has become a key priority in China, as demonstrated in the implementation of the Carbon Peak, Carbon Neutralization policy, leading to increasing concern of environmental performance at the corporate level. This paper measures the carbon emission of 1,089 Chinese companies through the EIO-LCA-based approach. Then we examine the impacts of international crude oil price fluctuations and the corporate development level on carbon emissions of individual companies. Our results indicate that an increase in international crude oil price uncertainty could inhibit the company’s carbon emission. In parallel, we find that there might exist an environmental Kuznets curve (EKC) inverted U-shaped correlation between the company’s development level and its environmental performance. However, some exceptions to corporate carbon performance may emerge, resulting from specific corporate characteristics such as the state-owned nature and whether the firm is listed on the stock exchange. Our results could help companies optimize their internal carbon emission structure during the low-carbon transition process and contribute to effective policy regulations towards the target of carbon reduction.

Three-dimensional (3D) hybrid of nanocarbons is a very promising way to the high-performance design of electrocatalysis materials. However, sp3-like defect structure, a combination of high strength and conduction of graphene and carbon nanotubes (CNTs) is rarely reported. Herein, 3D neural-like hybrids of graphene (from reduced graphene oxide) and carbon nanotubes (CNTs) have been integrated via sp3-like defect structure by a hydrothermal approach. The sp3-like defect structure endows 3D nanocarbon hybrids with an enhanced carrier transfer, high structural stability, and electrocatalytic durability. The neural-like structure is shown to demonstrate a cascade effect of charges and significant performances regarding bio-electrocatalysis and lithium-sulfur energy storage. The concept and mechanism of “sp3-like defect structure” are proposed at an atomic/nanoscale to clarify the generation of rational structure as well as the cascade electron transfer.

It is very challenging to completely break the corona symmetry of polymer vesicles as usually their inner and outer coronas have the same constituents. Herein, we propose a novel micelle-to-vesicle...

Die gemeinsame katalytische Umsetzung von Methan mit Kohlendioxid zur Erzeugung von Synthesegas (2H2+2CO) umfasst komplizierte Elementarschritte, und fast alle Elementarreaktionen werden praktisch bei den gleichen Hochtemperaturbedingungen der Thermokatalyse durchgeführt. Hier zeigen wir durch massenspektrometrische Experimente, dass RhTiO2- die gemeinsame Umsetzung von CH4 und CO2 zu freiem 2H2+CO und einem adsorbierten CO(COads) bei Raumtemperatur fördert; der einzige Elementarschritt, der die Zufuhr von externer Energie erfordert, ist die Desorption von COadsvom RhTiO2CO- zur Rückbildung von RhTiO2-. Die aktuelle Studie identifiziert nicht nur eine vielversprechende aktive Spezies für die Methan-Trockenreformierung (CO2-Reformierung) zu Synthesegas, sondern unterstreicht auch die Bedeutung der Temperaturkontrolle über Elementarschritte in der angewandten Katalyse, die die Kohlenstoffabscheidung durch Methanpyrolyse erheblich mindern könnte.

In order to study the impact of CO2 during n-heptane ignition delay under O2/CO2 conditions, this study presents a numerical and experimental study in four cases (40 mol.% O2/60 mol.% CO2, 50 mol.%...

As a wide band gap semiconductor material, tin oxide (SnO2) has been widely used in gas sensing, optoelectronics and catalysis. The complex micro and nanoscale three-dimensional (3D) geometric structures endow the conventional SnO2 ceramics with novel properties and functionalities. Nevertheless, ceramics cannot be cast or machined easily due to their high mechanical toughness and resistance. The additive manufacturing opens a great opportunity for flexibly geometrical shaping, while the arbitrary shaping of SnO2 ceramics at micro and nanoscale is always a challenge. Herein, preceramic monomers which can be polymerized under ultrafast laser irradiation, were utilized to form complex and arbitrary 3D preceramic polymer structures. After calcination treatment, these green-body structures could be converted into pure high-dense SnO2 ceramics with uniform shrinkage, and the feature size was down to submicron. Transmission electron microscopy (TEM) analysis displays that the printed SnO2 ceramic nanostructures can be nanocrystallized with grain sizes of 2.5 ± 0.4 nm. This work provides the possibility of manufacturing 3D SnO2 ceramic nanostructures arbitrarily with sub-100 nm resolution, thus making it promising for the applications of SnO2 in different fields.

Alkaline earth metal salts are environmentally friendly and economical. They have attracted much attention in the process of biomass conversion, especially for isomerization and dehydration. However, the lack of understanding of the alkaline earth metal-mediated catalytic mechanism prevents the achievement of high HMF yields from glucose or fructose. Herein, we performed experimental and theoretical studies on CaCl2-catalyzed glucose-to-fructose isomerization and fructose-to-HMF dehydration. In CaCl2 solution, the highest fructose yield (33.6%) from glucose can be achieved at 80 °C. Meanwhile, the presence of CaCl2 in fructose-to-HMF dehydration notably improved fructose conversion. A “one-pot” isomerization–dehydration of glucose to prepare HMF was designed and 100% conversion and 52.1% HMF yield were obtained. The CaCl2 solution can be reused for five runs while maintaining catalytic activity without regeneration. Through 1H NMR, 13C NMR, DOSY-NMR and DFT calculations, we concluded that the coordination between the C1/C2 sites of the β-glucopyranose tautomer and CaCl2 promoted the 1,2-intramolecular hydride shift of glucose, thus rapidly converting glucose into fructose. Similarly, Ca2+ can complex with the C2/C6-OH of β-D-fructofuranose and stabilize this tautomer, which easily forms HMF. This is the main reason that CaCl2 can promote the preparation of HMF from fructose.

The diagnosis and therapy of tumors are challenging problems in the medical field. Peptides are derived from living organisms with excellent biocompatibility, low-toxicity/non-toxicity, and negligible immunogenicity, and they have been widely used in the field of biomedicine, especially in tumor sensing and treatment. In recent years, a series of technologies in peptide research (including polypeptide synthesis, phage screening, sequencing, and computer-aided molecular simulations) and the discovery of tumor targeting peptide have been developed. In this review, we summarized the progress of peptide-based materials in tumor therapy, including the development and screening of peptides, and two peptide targeting tumor strategies: targeting tumor high-expressing receptors and targeting tumor microenvironment. We also summarized various tumor imaging methods and treatment methods based on peptides. Furthermore, the advantages and challenges of peptides in the current tumor field and the possible solutions are also discussed.

Metal-organic frameworks (MOFs) represent an emerging class of platforms to assemble single site photocatalysts for artificial photosynthesis. In this work, we report a new CO2 reduction photocatalyst (UiO-68-Fe-bpy) based on a robust Zr(iv)-MOF platform with incorporated Fe(bpy)Cl3 (bpy refers to the 4'-methyl-[2,2'-bipyridine] moiety) via amine-aldehyde condensation. We show that this hybrid catalyst can reduce CO2 to form CO under visible light illumination with excellent selectivity and enhanced activity with respect to its parent MOF and corresponding homogeneous counterpart. Using steady state and transient absorption (TA) spectroscopy, we show that the enhanced photocatalytic activity of UiO-68-Fe-bpy is attributed to the elongated excited state lifetime of Fe(bpy)Cl3 after being incorporated to the UiO-68-NH2 platform. This work demonstrates the great potential of MOFs as a next generation platform for solar fuel conversion.

The severe acute respiratory syndrome coronavirus 3C-like protease has been proposed to be a key target for structurally based drug design against SARS. The enzyme exists as a mixture of dimer and monomer, and only the dimer was considered to be active. In this report, we have investigated, using molecular dynamics simulation and mutational studies, the problems as to why only the dimer is active and whether both of the two protomers in the dimer are active. The molecular dynamics simulations show that the monomers are always inactive, that the two protomers in the dimer are asymmetric, and that only one protomer is active at a time. The enzyme activity of the hybrid severe acute respiratory syndrome coronavirus 3C-like protease of the wild-type protein and the inactive mutant proves that the dimerization is important for enzyme activity and only one active protomer in the dimer is enough for the catalysis. Our simulations also show that the right conformation for catalysis in one protomer can be induced upon dimer formation. These results suggest that the enzyme may follow the association, activation, catalysis, and dissociation mechanism for activity control.

Chronic obstructive pulmonary disease (COPD) is becoming a leading cause of morbidity and mortality in China. In the IMPACT trial, fluticasone furoate[FF]/umeclidinium[UMEC]/vilanterol[VI] single-inhaler triple therapy demonstrated lower rates of moderate/severe exacerbations than dual therapy with FF/VI or UMEC/VI in patients with symptomatic COPD and a history of exacerbations. This analysis investigates the China cohort and its consistency with the overall ITT population. 10,355 patients were randomized 2:2:1 to once-daily FF/UMEC/VI 100/62.5/25 µg, FF/VI 100/25 µg, or UMEC/VI 62.5/25 µg for 52 weeks. Endpoints included: annual rates of exacerbations, time-to-first on-treatment moderate/severe exacerbation and change from baseline in trough forced expiratory volume in 1 s (FEV1) at Week-52. Clinical trial registration is NCT02164513 (CTT116855). 535 patients (5.2%) were from China. Annual on-treatment moderate/severe exacerbation rate was 0.81 with FF/UMEC/VI versus 0.96 with FF/VI (rate ratio: 0.84; 95% confidence interval [CI]: 0.64, 1.11; p = .227) and 0.80 with UMEC/VI (rate ratio: 1.02; 95% CI: 0.72, 1.44; p = .929). Hazard ratio for time-to-first moderate/severe exacerbation was 0.84 (95% CI: 0.63, 1.11; p = .218) for FF/UMEC/VI versus FF/VI and 0.89 (95% CI: 0.62, 1.27; p = .516) versus UMEC/VI. Significant improvements in mean change from baseline in trough FEV1 were observed for FF/UMEC/VI versus FF/VI (treatment difference 137 mL; 95% CI: 86, 188; p p = .050). Health status was improved with FF/UMEC/VI versus both dual therapies. Results were similar to the overall ITT population. No new safety signals were identified. Single-inhaler triple therapy with FF/UMEC/VI versus FF/VI or UMEC/VI reduced the rate and risk of exacerbations, and improved lung function and health status in the China cohort similar to the overall ITT population. No new safety signals were identified.

This study investigated the effects of granular activated carbon (GAC) dosing on the co-anaerobic digestion of municipal sludge and food waste. It was found that methane production increased in the...

Background Mounting evidence has demonstrated the vital importance of tumor-associated macrophages (TAMs) and exosomes in the formation of the premetastatic niche. However, the molecular mechanisms by which tumor-derived exosomal miRNAs interact with TAMs underlying premetastatic niche formation and colorectal cancer liver metastasis (CRLM) remain largely unknown. Methods Transmission electron microscopy and differential ultracentrifugation were used to verify the existence of exosomes. In vivo and in vitro assays were used to identify roles of exosomal miR-934. RNA pull-down assay, dual-luciferase reporter assay, etc. were applied to clarify the mechanism of exosomal miR-934 regulated the crosstalk between CRC cells and M2 macrophages. Results In the present study, we first demonstrated the aberrant overexpression of miR-934 in colorectal cancer (CRC), especially in CRLM, and its correlation with the poor prognosis of CRC patients. Then, we verified that CRC cell-derived exosomal miR-934 induced M2 macrophage polarization by downregulating PTEN expression and activating the PI3K/AKT signaling pathway. Moreover, we revealed that hnRNPA2B1 mediated miR-934 packaging into exosomes of CRC cells and then transferred exosomal miR-934 into macrophages. Interestingly, polarized M2 macrophages could induce premetastatic niche formation and promote CRLM by secreting CXCL13, which activated a CXCL13/CXCR5/NFκB/p65/miR-934 positive feedback loop in CRC cells. Conclusions These findings indicate that tumor-derived exosomal miR-934 can promote CRLM by regulating the crosstalk between CRC cells and TAMs. These findings reveal a tumor and TAM interaction in the metastatic microenvironment mediated by tumor-derived exosomes that affects CRLM. The present study also provides a theoretical basis for secondary liver cancer.

The dehydration of cellulose in polar aprotic solvents produces high-value anhydro-sugars, opening up a new avenue for the utilization of cellulose. However, there are still some problems that need to be solved. Herein, we selected some carbohydrates (e.g. cellulose, starch, cellobiose, maltose, methyl-β-D-glucopyranoside and methyl-α-D-glucopyranoside) to examine the influence of different glycosidic bonds and substituents on the preparation of levoglucosan (LGA). The results of LGA yields, reaction rate constants and activation energies from different saccharides show that β-glycosidic bond is more vulnerable to break, forming LGA more easily. The activation energies of the latter 4 carbohydrates are 89.9, 104.2, 93.3, 113.6 kJ/mol, respectively. The strength of acid affects the dehydration process of cellulose greatly. These acids whose pKa values are between − 3 and − 2, including p-toluenesulfonic acid, methanesulfonic acid, and sulfuric acid, can achieve the best yields of LGA and levoglucosenone (LGO). Accordingly, those acids with higher pKa value have no catalytic activity, whereas the rate of cellulose degradation using lower pKa valued acids as catalyst is too fast to be efficiently monitored and carbonization is severe. The side reaction of cellulose hydrolysis and the formation of byproducts including 5-hydroxymethylfurfural (HMF) and furfural (FF) could be suppressed effectively through the addition of phosphorus pentoxide as water absorbent into the reaction system. The molar concentration ratio of LGO and (HMF + FF + Glucose) reached 12.04, which is 105% higher than those without water absorbent. This ratio can reach 21.38 in LGA dehydration into LGO process when phosphorus pentoxide was added.

Background L-tert-Leucine has been widely used in pharmaceutical, chemical, and other industries as a vital chiral intermediate. Compared with chemical methods, enzymatic methods to produce L-tert-leucine have unparalleled advantages. Previously, we found a novel leucine dehydrogenase from the halophilic thermophile Laceyella sacchari (LsLeuDH) that showed good thermostability and great potential for the synthesis of L-tert-leucine in the preliminary study. Hence, we manage to use the LsLeuDH coupling with a formate dehydrogenase from Candida boidinii (CbFDH) in the biosynthesis of L-tert-leucine through reductive amination in the present study. Result The double-plasmid recombinant strain exhibited higher conversion than the single-plasmid recombinant strain when resting cells cultivated in shake flask for 22 h were used. Under the optimized conditions, the double-plasmid recombinant E. coli BL21 (pETDute-FDH-LDH, pACYCDute-FDH) transformed 1 mol·L-1 trimethylpyruvate (TMP) completely into L-tert-leucine with greater than 99.9% ee within 8 h. Conclusions The LsLeuDH showed great ability to biosynthesize L-tert-leucine. In addition, it provided a new option for the biosynthesis of L-tert-leucine. How to cite Wang L, Zhu W, Gao Z, et al. Biosynthetic L-tert-leucine using Escherichia coli co-expressing a novel NADH-dependent leucine dehydrogenase and a formate dehydrogenase. Electron J Biotechnol 2020;47. https://doi.org/10.1016/j.ejbt.2020.07.001

Scope Peanut stem and leaf (PSL), a traditional Chinese medicine, is widely used as a dietary supplement to improve sleep quality, however, the underlying mechanism is unclear. Here, we aimed to determine whether active compounds in PSL extract exert their effects by mediating neuronal excitability. Methods and results Aqueous PSL extract (500 mg/kg BW) increased the duration of total sleep (TS), slow wave sleep (SWS) and rapid eye movement sleep (REMS) in BALB/c mice after 7 and 14 continuous days of intragastric administration. Two PSL extract components with flavonoid-like structures: 4',7-di-O-methylnaringenin (DMN, 61 μg/kg BW) and 2'-O-methylisoliquiritigenin (MIL, 12 μg/kg BW), showed similar effects on sleep in BALB/c mice. Moreover, incubation with DMN (50 μM) and MIL (50 μM) acutely reduced voltage-gated sodium and potassium currents and suppressed the firing of evoked action potential in mouse cortical neurons, indicating the inhibition on neuronal excitability. Meanwhile, RNA-seq analysis predicted the potential regulation of voltage-gated channels, which is according with the molecular docking simulation that both MIL and DMN can bind to Nav 1.2. Conclusions DMN and MIL are the active ingredients of PSL that improve sleep quality, suggesting that PSL promotes sleep by regulating the excitability of neurons. This article is protected by copyright. All rights reserved.

[Zn6(L)4(DMF)2(H2O)4](1,4-Dioxane)2(DMF)10(H2O)4 (1, L = 4,4′,4″-(benzene-1,3,5-triyltris(oxy))tribenzoate), the metal-organic cage, was produced via Zn(NO3)2·6H2O reacting with the H3L ligand in the mixed solvent of DMF and water. The heterogeneous catalytic activities of the complex 1 for the aldehydes cyanidation under the conditions of free solvent were studied, which indicates that the removal of coordination solvents could greatly improve the catalytic activities. Furthermore, the inhibitory effect of the compound against the ovarian cancer cells was assessed. The mi-RNA16 relative expression level was measured after exposure to the compound with real-time reverse transcription-polymerase chain reaction. The invasion and migration of cells after compound treatment were also detected by the transwell method.

Corncob is an abundant agricultural residue containing high content of hemicellulose. In this paper, the hemicellulosic hydrolysate was prepared from the hydrolysis of corncob using the solid acid sulfated zirconia as a catalyst. According to response surface analysis experiments, the optimum conditions for preparing hemicellulosic hydrolysate catalyzed by sulfated zirconia were determined as follows: solid (sulfated zirconia)-solid (corncob) ratio was 0.33, solid (corncob)-liquid (water) ratio was 0.09, temperature was 153 °C, and time was 5.3 h. Under the optimized conditions, the soluble sugar concentration was 30.12 g/L with a yield of 033 g/g corncob. Subsequently, xylitol production from the resulting hemicellulosic hydrolysate was demonstrated by Candida tropicalis, and results showed that the yield of xylitol from the hemicellulosic hydrolysate could be significantly improved on a basis of decolorization and detoxification before fermentation. The maximum yield of xylitol from the hemicellulosic hydrolysate fermented by C. tropicalis was 0.76 g/g. This study provides a new attempt for xylitol production from the hemicellulosic hydrolysate.

Pyrrosia petiolosa, Pyrrosia lingua and Pyrrosia sheareri are recorded as original plants of Pyrrosiae Folium (PF) and commonly used as Chinese herbal medicines. Due to the similar morphological features of PF and its adulterants, common DNA barcodes cannot accurately distinguish PF species. Knowledge of the chloroplast (cp) genome is widely used in species identification, molecular marker and phylogenetic analyses. Herein, we determined the complete cp genomes of three original species of PF via high-throughput sequencing technologies. The three cp genomes exhibited a typical quadripartite structure with sizes ranging from 158 165 to 163 026 bp. The cp genomes of P. petiolosa and P. lingua encoded 130 genes, whilst that of P. sheareri encoded 131 genes. The complete cp genomes were compared, and five highly divergent regions of petA-psbJ, matK-rps16, ndhC-trnM, psbM-petN and psaC-ndhE were screened as potential DNA barcodes for identification of Pyrrosia genus species. The phylogenetic tree we obtained indicated that P. petiolosa and P. lingua are clustered in a single clade and, thus, share a close relationship. This study provides invaluable information for further studies on the species identification, taxonomy and phylogeny of Pyrrosia genus species.

Crotonaldehyde, a highly toxic α, β-unsaturated aldehyde, is a ubiquitous hazardous pollutant. Because of its extreme toxicity and ubiquity in all types of smoke, most current research focuses on the lung toxicity of such air pollutants. However, the specific mechanism of pulmonary toxicity caused by crotonaldehyde remains unclear, especially after long-term exposure to crotonaldehyde at low dose. Therefore, the aim of the present study is to determine whether crotonaldehyde-induced oxidative damage and inflammation promote apoptosis in rats via the mitochondrial pathway using histopathology, immunohistochemistry, biochemistry analysis and Western blot analysis. The results show that crotonaldehyde elicited oxidative damage and inflammation in rats in a concentration-dependent manner. Crotonaldehyde-induced lung injury which was confirmed by H&E, Masson's trichrome staining and TUNEL. And crotonaldehyde-induced lung cell apoptosis showed a concentration-response relationship. Immunohistochemistry and Western blot results showed that apoptotic mitochondrial signaling pathway is abnormally activated in crotonaldehyde-induced lung injury. Collectively, this study demonstrates that exposure of rats to crotonaldehyde induces lung injury by inducing apoptosis, which is related to oxidative damage and inflammation through mitochondrial pathway.

Stimuli-responsive anticancer drug delivery vehicles have attracted increasing attention in nanomedicine. However, controlled drug release in vivo is still an important challenge, as traditional stimuli lack maneuverability. To solve this problem, we designed an ultrasound and pH-responsive polymersome by self-assembly of poly(ethylene oxide)-block-poly(2-(diethylamino)ethyl methacrylate)-stat-poly(methoxyethyl methacrylate) [PEO-b-P(DEA-stat-MEMA)], where PEO acts as the corona-forming block, DEA acts as the endosomal escape segment, and MEMA acts as the ultrasound-responsive segment. This strategy combines the advantages of noninvasive ultrasonic stimulus which can be applied from outside to any organ regardless of depth, and the weakly acidic microenvironment of tumor tissue. In vitro experiments confirmed excellent endosomal escape ability, on-demand drug release behavior, low cytotoxicity, and high intracellular delivery efficiency of polymersomes. In vivo antitumor tests revealed that in the presence of sonication, the anticancer drug was released at an accelerated rate from these ultrasound-responsive polymersomes, and the DOX-loaded polymersomes + sonication group significantly inhibited tumor growth (95% reduction in tumor mass) without any side effects. Overall, this ultrasound-responsive polymersome provides us with a fresh insight into designing next-generation stimuli-responsive drug carriers with better maneuverability and higher chemotherapeutic efficiency.

Rare earth metal (RE = La, Pr, Nd, Y)-doped CoCeOx catalysts were prepared and evaluated for eliminating chlorobenzene (CB). Characterization results showed that the doped RE metal simultaneously a...

A molecularly imprinted photoelectrochemical sensor based on AgBiS2/Bi2S3 was developed for detection of insecticide propoxur. AgBiS2/Bi2S3 composites were synthesized on Ti substrate by solvothermal method. By using propoxur as a template molecule and o-phenylenediamine as a functional monomer, a molecularly imprinted polymer film was formed by electropolymerization on AgBiS2/Bi2S3 composite material-modified Ti electrode for specific recognition of propoxur. The specific binding of propoxur with the imprinted cavity hindered the electron donor from passing through the cavity to the surface of the electrode, resulting in a decrease in photocurrent, and then propoxur was detected. The logarithm of the concentration of propoxur was linear with the photocurrent in the range of 1.0 × 10−12−5.0 × 10−10 mol/L, and the detection limit was 2.3 × 10−13 mol/L. The sensor was used for detection of propoxur residues in actual sample such as fruits, and the recoveries of the spiked standard were 101.0%–;103.1%.

In present study, we have mined a transaminase (TA) from Rhizobium sp. from the pool of fully sequenced genomes by using an ω-TA sequence from Vibrio fluvialis JS17 as a template in a BLASTP search. The protein sequence of the TA from Rhizobium sp. exhibits 53% sequence identity to that from V. fluvialis. The TA with S-selectivity showed close evolutionary relationship with a pyruvate transaminase from Alcaligenes denitrificans Y2k-2 and an S-selective aminotransferase from Sphaerobacter thermophilus. The gene of the ω-TA was inserted into pET-28a and functionally expressed in E. coli BL21. Results showed that the recombinant ω-TA has a specific activity of 7.46 U/mg at pH 8.0, 30 ℃. The substrate specificity test found the ω-TA presented significant reactivity toward aromatic amino donors and amino acceptors containing aldehydes. More importantly, the ω-TA also exhibited a good affinity towards some cyclic substrates. The homology model of the ω-TA was built by Discovery Studio and docking was performed to describe the relative activity towards some substrates.

The copper coordination complex [CuCl(2-OHNA)H2O]·H2O (1) was synthesized by the reaction of CuCl2·2H2O with in situ generated 2-hydroxynicotinic acid and its crystal structure was determined by single X-ray diffraction methods. It was further characterized by FT-IR spectroscopy, elemental analyses, and thermogravimetric analysis. Complex 1 crystallizes in monoclinic space group P21/c with a = 8.9797(13), b = 14.196(2), c = 7.0738(11) A, β = 96.897(2), V = 895.2(2) A3, Mr = 273.12, Dc = 2.027 g/cm3, and Z = 4. In the structure, complex 1 is linked into 2D sheets via intermolecular hydrogen bonding [N1–H1···O2 (−x+1, y − 1/2, − z+1/2); O5–H10···O2 (− x+1, y + 1/2, − z+1/2); O4–H9···O5 (x, y − 1, z); O4–H8···O5 (− x+2, y + 1, − z)]. The catalytic property of 1 was also investigated in the selective oxidation of benzyl-alkanes using TBHP as oxidant. Under optimized conditions, 1 exhibited high catalytic activity and selectivity toward the corresponding aryl ketones. The copper coordination complex [CuCl(2-OHNA)H2O]·H2O (1) was synthesized by the reaction of CuCl2·2H2O with in situ generated 2-hydroxynicotinic acid and the catalytic property of 1 was also investigated in the selective oxidation of benzyl-alkanes using TBHP as oxidant.

Phenolic compounds are problematic byproducts generated from lignocellulose pretreatment. In this study, the feasibility degradation of syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) by Bio-Electro-Fenton (BEF) system with a novel Fe–Mn/graphite felt (Fe–Mn/GF) composite cathode were investigated. The nano-scale Fe–Mn multivalent composite catalyst with core shell structure distributed more evenly on GF surface to form a catalyst layer with higher oxygen reduction reaction performance. Accordingly, the maximum power density generated with Fe–Mn/GF cathode was 48.1% and 238.9% higher than Fe/GF and GF respectively, which further enhanced the in situ generation of H2O2 due to the superiority of nano-scale core shell structure and synergistic effect of Fe and Mn species. The degradation efficiency of the three phenolic compounds in the BEF system could reached 100% after optimization of influencing parameters. Furthermore, a possible SA degradation pathway by BEF process in the present system was proposed based on the detected intermediates. These results demonstrated an efficient approach for the degradation of phenolic compounds derived from lignocellulose hydrolysates.

A Cu2O/(001)TiO2@Ti3C2Tx photocatalyst was synthesized via a wet-chemistry reduction method by N, N-dimethylformamide (DMF). By scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), it was revealed that the surface coverage of photocatalyst increased with the loading amount of Cu2O, while the particle size of Cu2O did not change significantly. The photocatalytic activity and mechanism of ternary Cu2O/(001)TiO2@Ti3C2Tx photocatalyst heavily depend on the surface coverage of copper species. When the surface coverage of photocatalyst by Cu2O was low, the Ti3C2Tx acted as hole reservoir. Cu2O was firstly reduced in situ to metallic copper by excited electrons. Then the reverse movement of carriers enabled the spatial separation of photogenerated electron-hole pairs, and afforded relatively high hydrogen evolution (more than 1100 μmol h−1 (g CuOx TiO2)−1). When the coverage of Cu2O on (001)TiO2@Ti3C2Tx was too high at high loading amounts, Ti3C2Tx failed to play the role of hole trapping. Under that circumstance, the photocatalytic reaction follows p-n junction mechanism, leading to low hydrogen productivity. The results here shed light on the relationship between structure and activity of Cu2O/(001)TiO2@Ti3C2Tx, which was conducive to the development of the MXene-based photocatalysts.

Crotonaldehyde is a hazardous pollutant present in cigarette smoke and automobile exhausts that is generated by lipid peroxidation, and harmful to reproductive organs. Although we are often exposed to low doses of crotonaldehyde daily, its adverse effects on the reproductive organs have not been fully elucidated. To elucidate them, we administered crotonaldehyde (0, 2.5, 4.5, and 8.5 mg/kg) by gavage for 150 days to male Wister rats, and evaluated its effect on their testicular tissues. Body weight, testis coefficient, sperm count, and motility decreased. Reactive oxygen species and malondialdehyde levels in the 8.5 and 4.5 mg/kg groups significantly increased as antioxidant enzyme activity decreased. Testicular cell apoptosis rate in the exposed groups increased. Testicular enzyme activity and reproductive hormone levels were significantly altered in the 8.5 and 4.5 mg/kg groups. Therefore, long-term exposure to crotonaldehyde may induce oxidative stress, resulting in testicular cell apoptosis, and testicular enzyme and hormone level alteration.

Bacteria maintain a stable cell size and a certain DNA content through proliferation as described by classic growth laws. How cells behave when this inherent scaling is broken, however, has rarely been interrogated. Here we engineered Escherichia coli cells with extremely low DNA contents using a tunable synthetic tool CRISPRori that temporarily inhibited chromosome replication initiation. A detailed mechanistic model coupling DNA replication, cell growth, and division revealed a fundamental DNA-centric growth law, which was validated by two observations. First, lineage dynamics were robust to large CRISPRori perturbations with division cycles rapidly restoring through a timer mechanism rather than the adder rule. Second, cellular growth transitioned into a linear regime at low DNA-cytoplasm ratios. Experiments and theory showed that in this regime, cellular resource was redirected to plasmid-borne gene expression. Together with the ability of CRISPRori to bi-directionally modulate plasmid copy numbers, these findings suggest a novel strategy for bio-production enhancement.

Uterine M1/M2 macrophages activation states undergo dynamic changes throughout pregnancy, and inappropriate macrophages polarization can cause adverse pregnancy outcomes, especially during the peri-implantation period. Our previous studies have confirmed that Cytochrome P450 26A1 (CYP26A1) can affect embryo implantation by regulating uterine NK cells and DCs. The aim of this study was to investigate whether CYP26A1 regulates the polarization of uterine macrophages in early pregnancy. Here, we observed that Cyp26a1 was significantly upregulated in M1 as compared with M2 of uterine macrophages, Raw264.7 and iBMDM. Knockdown of CYP26A1 in mice uterine significantly decreased the number of embryo implantation sites and the proportion of CD45+F4/80+CD206− M1-like uterine macrophages. Primary uterine macrophages treated with anti-CYP26A1 antibody expressed significantly lower levels of M1 markers Nos2, Il1b, Il6 and Tnf-a. In CYP26A1 knockout Raw264.7 cells, the protein levels of M1 markers TNF-α, IL-6 and CD86 were significantly decreased as compared with the wild type cells. Moreover, CYP26A1 deficiency decreased the ability to produce nitric oxide and increased the phagocytosis capacity of Raw264.7 cells under M1 stimulation state. The re-introduction of CYP26A1 partially reversed the polarization levels of M1 in CYP26A1 knockout Raw264.7 cells. CYP26A1 may regulate the polarization of uterine macrophages to M1 through Stap1 and Slc7a2. In summary, these results indicate that CYP26A1 plays a significant role in macrophage polarization, and knockdown of CYP26A1 can cause insufficient M1 polarization during the peri-implantation period, which has adverse effects on blastocyst implantation.

Acyclovir (ACV) is an effective and selective antiviral drug, and the study of its toxicology and the use of appropriate detection techniques to control its toxicity at safe levels are extremely important for medicine efforts and human health. This review discusses the mechanism driving ACV’s ability to inhibit viral coding, starting from its development and pharmacology. A comprehensive summary of the existing preparation methods and synthetic materials, such as 5-aminoimidazole-4-carboxamide, guanine and its derivatives, and other purine derivatives, is presented to elucidate the preparation of ACV in detail. In addition, it presents valuable analytical procedures for the toxicological studies of ACV, which are essential for human use and dosing. Analytical methods, including spectrophotometry, high performance liquid chromatography (HPLC), liquid chromatography/tandem mass spectrometry (LC-MS/MS), electrochemical sensors, molecularly imprinted polymers (MIPs), and flow injection–chemiluminescence (FI-CL) are also highlighted. A brief description of the characteristics of each of these methods is also presented. Finally, insight is provided for the development of ACV to drive further innovation of ACV in pharmaceutical applications. This review provides a comprehensive summary of the past life and future challenges of ACV.

Encapsulation of lithium in the confined spaces within individual nanocapsules is intriguing and highly desirable for developing high-performance Li metal anodes. This work aims for a mechanistic understanding of Li encapsulation and its confined growth kinetics inside 1D enclosed spaces. To achieve this, amorphous carbon nanotubes are employed as a model host using in situ transmission electron microscopy. The carbon shells have dual roles, providing geometric/mechanical constraints and electron/ion transport channels, which profoundly alter the Li growth patterns. Li growth/dissolution takes place via atom addition/removal at the free surfaces through Li+ diffusion along the shells in the electric field direction, resulting in the formation of unusual Li structures, such as poly-crystalline nanowires and free-standing 2D ultrathin (1-2 nm) Li membranes. Such confined front-growth processes are dominated by Li {110} or {200} growing faces, distinct from the root growth of single-crystal Li dendrites outside the nanotubes. Controlled experiments show that high lithiophilicity/permeability, enabled by sufficient nitrogen/oxygen doping or pre-lithiation, is critical for the stable encapsulation of lithium inside carbonaceous nanocapsules. First-principles-based calculations reveal that N/O doping can reduce the diffusion barrier for Li+ penetration, and facilitate Li filling driven by energy minimization associated with the formation of low-energy Li/C interfaces.

Ischemia-reperfusion injury (IRI) remains as a critical challenge for organ transplantation. Herein, an enzyme therapeutic based on superoxide dismutase and catalase for effective mitigation of IRI and pathogen-induced liver injury is reported, providing a therapeutic for organ transplantation and other diseases.

The treatment approach to advanced, ALK-positive non-small cell lung cancer (NSCLC) utilizing sequential ALK tyrosine kinase inhibitors (TKIs) represents a paradigm of precision oncology. Lorlatinib is currently the most advanced, potent and selective ALK tyrosine kinase inhibitor (TKI) in the clinic. However, tumors invariably acquire resistance to lorlatinib, and after sequential ALK TKIs culminating with lorlatinib, diverse refractory compound ALK mutations can emerge. Here, we determine the spectrum of lorlatinib-resistant compound ALK mutations identified in patients after treatment with lorlatinib, the majority of which involve ALK G1202R or I1171N/S/T. By assessing a panel of lorlatinib analogs against compound ALK mutant in vitro and in vivo models, we identify structurally diverse lorlatinib analogs that harbor differential selective profiles against G1202R- versus I1171N/S/T-based compound ALK mutations. Structural analysis revealed that increased potency against compound mutations was achieved primarily through two different mechanisms of improved targeting of either G1202R- or I1171N/S/T-mutant kinases. Based on these results, we propose a classification of heterogenous ALK compound mutations designed to focus the development of distinct therapeutic strategies for precision targeting of compound resistance mutations following sequential TKIs.

Background MEK1/ERK signaling pathway plays an important role in most tumor progression, including colorectal cancer (CRC), however, MEK1-targeting therapy has little effective in treating CRC patients, indicating there may be a complex mechanism to activate MEK1/ERK signaling pathway except RAS activated mechanism. Methods To investigate the clinical significance of IMP3, we analyzed its expression levels in publicly available dataset and samples from Fudan University Shanghai Cancer Center. The effects of IMP3 on proliferation, migration, and invasion were determined by in vitro and in vivo experiments. To investigate the role of IMP3 in colon carcinogenesis, conditional IMP3 knockout C57BL/6 mice was generated. The IMP3/MEKK1/MEK/ERK signaling axis in CRC was screened and validated by RNA-sequencing, RNA immunoprecipitation, luciferase reporter and western blot assays. Results We find RNA binding protein IMP3 directly bind to MEKK1 mRNA 3′-UTR, which regulates its stability, promote MEKK1 expression and sequentially activates MEK1/ERK signaling. Functionally, IMP3 promote the malignant biological process of CRC cells via MEKK1/MEK1/ERK signaling pathway both in vitro and in vivo, Moreover, IMP3−/− mice show decreased the expression of MEKK1 as well as colorectal tumors compared with wild-type mice after treatment with azoxymethane/dextran sodium sulfate. Clinically, the expression of IMP3 and MEKK1 are positive correlated, and concomitant IMP3 and MEKK1 protein levels negatively correlate with metastasis in CRC patients. In addition, MEK1 inhibitor in combination with shRNA-IMP3 have a synergistic effect both in vitro and in vivo. Conclusion Our study demonstrates that IMP3 regulates MEKK1 in CRC, thus activating the MEK1/ERK signaling in the progression of colorectal cancer, Furthermore, these results provide new insights into potential applications for combining MEK1 inhibitors with other target therapy such as IMP3 in preclinical trials for CRC patients.

Catalytic co-conversion of methane with carbon dioxide to produce syngas (2 H2+2 CO) involves complicated elementary steps and almost all the elementary reactions are performed at the same high temperature conditions in practical thermocatalysis. Here, we demonstrate by mass spectrometric experiments that RhTiO2- promotes the co-conversion of CH4 and CO2 to free 2 H2+CO and an adsorbed CO (COads) at room temperature; the only elementary step that requires the input of external energy is desorption of COads from the RhTiO2CO- to reform RhTiO2-. This study not only identifies a promising active species for dry (CO2) reforming of methane to syngas, but also emphasizes the importance of temperature control over elementary steps in practical catalysis, which may significantly alleviate the carbon deposition originating from the pyrolysis of methane.

Salmonella is one of the major pathogenic bacteria causing food-borne diseases. The rapid detection of Salmonella in food is of great significance to food safety. In this study, the loop-mediated isothermal amplification (LAMP) method was developed and the primers were designed targeting the invA gene of Salmonella. Then, the standard samples of recombinant invA-plasmid and 100 retail meat samples were tested by LAMP and compared with the results tested by the conventional PCR and the routine China National Food Safety Standard Methods for Food Microbiological Examination-Salmonella (GB/T4789.4-2016), respectively. The results showed that Salmonella strains of 8 different serotypes were amplified successfully by the developed LAMP assay. And, it was 1000-fold more sensitive than the conventional PCR with the analytical sensitivity of 8×102 copies/μL of the standard sample of invA-plasmid. The results were visualized directly by adding Calcein/MnCl2 into the LAMP reaction tube and the positively amplified products turned green after an incubation of 2 min. In the parallel detection, the positive rate of Salmonella by the LAMP assay was highly correlated with the routine China national standard method. The results of the study demonstrated that the developed LAMP assay is a simple, rapid, strongly specific, highly sensitive and visual detection method for Salmonella.

An extracellular thermostable xylanase (XynNTU) from Paenibacillus campinasensis NTU-11, consisted of a glycoside hydrolase (GH) family 11 catalytic domain, a Gly/Pro-rich linker sequence (LS) and a family 6 carbohydrate-binding module (CBM6), was identified and expressed in E. coli BL21. The purified XynNTU had a specific activity of 2750 U/mg and an optimal activity at 60 °C and pH 7.0, and retained a residual activity of 58.4% after incubation (60 °C, 48 h). Two truncated mutants, CBM6-truncated form XynNTU-CDLS, CBM6 and linker-truncated form XynNTU-CD, possessed similar values of optimum pH and temperature as the native XynNTU. XynNTU-CD displayed a lower thermostability than XynNTU, whereas for XynNTU-CDLS, more than 90% of residual activity was remained (60 °C, 48 h), indicating that this enzyme presented a higher thermostability than that of the majority of reported GH11 xylanases. Furthermore, XynNTU and two mutants maintained more than 70% of residual activity at pH values of 5–9. Kinetic measurements suggested that CBM6 had a crucial function in the ability of the enzyme to bind and hydrolyze xylan substrates, while LS had a relatively mild influence. Collectively, a noticeable thermostability and a high specific activity of XynNTU and its truncated form XynNTU-CDLS highlights their potentials for diverse industrial applications.

Reactive Oxygen Species (ROS) are present in high amount in patients with tumors, and these ROS can kill and destroy tumor cells. Thus, tumor cells upregulate ROS-related genes to protect themselves and reduce their destruction. Cancer cells already damaged by ROS can be repaired by expressing DNA repair genes consequently promoting their proliferation. In this work, lung adenocarcinoma (LUAD) transcriptome data in the TCGA database was analyzed and samples were clustered into 5 ROS-related categories and 6 DNA repair categories. Survival analysis revealed a significant difference in patient survival between the two classification methods. In addition, the samples corresponding to the two categories overlap, thus, the gene expression profile of the same sample with different categories and survival prognosis was further explored, and the connection between ROS-related genes and DNA repair genes was investigated. The interactive sample recombination classification was used, revealing that the patient's prognosis was worse when the ROS-related genes and DNA repair genes were expressed at the same time. The further research on the potential regulatory network of the two categories of genes and the correlation analysis revealed that ROS-related genes and DNA repair genes have a mutual regulatory relationship. The ROS-related genes NQO1, TXNRD1, and PRDX4 could establish links with other DNA repair genes through the DNA repair gene NEIL3, thereby increasing the growth of tumor cells and balancing the level of ROS, leading to tumor cell death and constant damage to the tumor cell repair system, thus prolonging patient survival. Thus, targeting ROS-related genes and DNA repair genes might be a promising strategy in the treatment of LUAD. Finally, a survival prognostic model of ROS-related genes and DNA repair genes was established (TERT, PRKDC, PTTG1, SMUG1, TXNRD1, CAT, H2AFX and PFKP), the risk score might be used as an independent prognostic factor in LUAD patients.

C16H15FN2O2, monoclinic, P21/c (no. 14), a = 6.0573(3) Å, b = 13.8341(6) Å, c = 33.0876(15) Å, β = 92.837(2)°, Z = 8, V = 2769.3(2) Å3, R gt(F) = 0.0581, wR ref(F 2) = 0.1605, T = 173(2) K.

Here, we fabricated a novel photoelectrochemical (PEC) aptasensor based on Br,N-codoped TiO2/CdS quantum dots (QDs) sensitization structure with excellent energy level arrangement for supersensitiv...