Tetrastigma hemsleyanum (Sanyeqing) root extracts evoke S phase arrest while inhibiting the migration and invasion of human pancreatic cancer PANC-1 cells.

BACKGROUND: Ethyl acetate extracts from Tetrastigma hemsleyanum (Sanyeqing) (EFT), a member of the Vitaceae plant family, have been shown to exhibit efficacy against a variety of cancers. In this light, our current study seeks to examine the mechanism of efficacy between EFT extracts and human pancreatic cancer PANC-1 cells. METHODS: The chemical components of EFT were analyzed by gas chromatography-mass spectrometry. The cytotoxicity of EFT on PANC-1 cells was measured using an MTT assay. In order to investigate EFT induction of cell cycle arrest, changes in cell-cycle distribution were monitored by flow cytometry. Wound healing and transwell assays were employed to investigate whether migration and invasion of PANC-1 cells were inhibited by EFT. Relative protein expression was detected using Western blot. RESULTS: GC-MS analysis of the chemical composition of EFT revealed that the majority of constituents were organic acids and their corresponding esters. EFT exhibits measurable cytotoxicity and inhibition of PANC-1 invasion. Growth inhibition was primarily attributed to downregulation of CDK2 which induces cell cycle arrest in the S-phase. Inhibition of metastasis is achieved through downregulation of mesenchymal-associated genes/activators, including ZEB1, N-cadherin, Vimentin, and Fibronectin. Meanwhile, the expression of E-cadherin was significantly increased by EFT treatment. Furthermore, downregulation of MMP-2 and MMP-9 were observed. CONCLUSION: Treatment of PANC-1 with EFT demonstrated measurable cytotoxic effects. Furthermore, EFT evoked S phase arrest while inhibiting the migration and invasion of PANC-1 cells. Additionally, EFT inhibited the epithelial to mesenchymal transition and MMPs expression in PANC-1 cells. This study serves to confirm the strong therapeutic potential of EFT while identifying the mechanisms of action.

The Extracts Derived from Artemisia japonica Thunb. Leaves Mitigate Oxidative Stress and Inflammatory Response Induced by LPS in RAW264.7 Cells through Modulation of the Nrf2/HO-1 Signaling Pathway.

Artemisia japonica Thunb. has been used as a traditional Chinese medicine and a vegetable for thousands of years in China. However, there are few reports on the chemical composition and biological activity of its leaves. Thus, this study aimed to evaluate the chemical composition, antioxidant and anti-inflammatory effects of water extracts of A. japonica leaves and their underlying mechanisms. A total of 48 compounds were identified in the water extract using UPLC-QTOF-MS2 analysis, with phenolic acids, particularly chlorogenic acid compounds, being the predominant components. The ethyl acetate fraction (EAF) contained most of the total phenolic content (385.4217 mg GAE/g) and displayed superior antioxidant capacity with the IC50DPPH•, IC50ABTS•+, and OD0.5reducing power at 10.987 µg/mL, 43.630 µg/mL and 26.883 µg/mL, respectively. Furthermore, EAF demonstrated potent antioxidant and anti-inflammatory effects in LPS-induced RAW264.7 cells by upregulating the Nrf2/HO-1 signal pathway. These findings highlight that A. japonica leaves possess remarkable abilities to mitigate inflammation and oxidative stress, suggesting their potential utilization as medicinal agents and food additives for promoting human health.

Liquiritin reduces chondrocyte apoptosis through P53/PUMA signaling pathway to alleviate osteoarthritis.

AIMS: The main pathological features of osteoarthritis (OA) include the degeneration of articular cartilage and a decrease in matrix synthesis. Chondrocytes, which contribute to matrix synthesis, play a crucial role in the development of OA. Liquiritin, an effective ingredient extracted from Glycyrrhiza uralensis Fisch., has been used for over 1000 years to treat OA. This study aims to investigate the impact of liquiritin on OA and its underlying mechanism. MATERIALS AND METHODS: Gait and hot plate tests assessed mouse behavior, while Micro-CT and ABH/OG staining observed joint morphological changes. The TUNEL kit detected chondrocyte apoptosis. Western blot and immunofluorescence techniques determined the expression levels of cartilage metabolism markers COL2 and MMP13, as well as apoptosis markers caspase3, bcl2, P53, and PUMA. KEGG analysis and molecular docking technology were used to verify the relationship between liquiritin and P53. KEY FINDINGS: Liquiritin alleviated pain sensitivity and improved gait impairment in OA mice. Additionally, we found that liquiritin could increase COL2 levels and decrease MMP13 levels both in vivo and in vitro. Importantly, liquiritin reduced chondrocyte apoptosis induced by OA, through decreased expression of caspase3 expression and increased expression of bcl2 expression. Molecular docking revealed a strong binding affinity between liquiritin and P53. Both in vivo and in vitro studies demonstrated that liquiritin suppressed the expression of P53 and PUMA in cartilage. SIGNIFICANCE: This indicated that liquiritin may alleviate OA progression by inhibiting the P53/PUMA signaling pathway, suggesting that liquiritin is a potential strategy for the treatment of OA.

Effect fraction of Bletilla striata (Thunb.) Reichb.f. alleviates LPS-induced acute lung injury by inhibiting p47phox/NOX2 and promoting the Nrf2/HO-1 signaling pathway.

BACKGROUND & AIMS: The effect fraction of Bletilla striata (Thunb.) Reichb.f. (EFBS), a phenolic-rich extract, has significant protective effects on lipopolysaccharide (LPS)-induced acute lung injury (ALI), but its composition and molecular mechanisms are unclear. This study elucidated its chemical composition and possible protective mechanisms against LPS-induced ALI from an antioxidant perspective. METHODS: EFBS was prepared by ethanol extraction, enriched by polyamide column chromatography, and characterized using ultra-performance liquid chromatography/time-of-flight mass spectrometry. The LPS-induced ALI model and the RAW264.7 model were used to evaluate the regulatory effects of EFBS on oxidative stress, and transcriptome analysis was performed to explore its possible molecular mechanism. Then, the pathway by which EFBS regulates oxidative stress was validated through inhibitor intervention, flow cytometry, quantitative PCR, western blotting, and immunofluorescence techniques. RESULTS: A total of 22 compounds in EFBS were identified. The transcriptome analyses of RAW264.7 cells indicated that EFBS might reduce reactive oxygen species (ROS) production by inhibiting the p47phox/NADPH oxidase 2 (NOX2) pathway and upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. Both in vitro and in vivo data confirmed that EFBS significantly inhibited the expression and phosphorylation of p47phox protein, thereby weakening the p47phox/NOX2 pathway and reducing ROS production. EFBS significantly increased the expression of Nrf2 in primary peritoneal macrophages and lung tissue and promoted its nuclear translocation, dose-dependent increase in HO-1 levels, and enhancement of antioxidant activity. In vitro, both Nrf2 and HO-1 inhibitors significantly reduced the scavenging effects of EFBS on ROS, further confirming that EFBS exerts antioxidant effects at least partially by upregulating the Nrf2/HO-1 pathway. CONCLUSIONS: EFBS contains abundant phenanthrenes and dibenzyl polyphenols, which can reduce ROS production by inhibiting the p47phox/NOX2 pathway and enhance ROS clearance activity by upregulating the Nrf2/HO-1 pathway, thereby exerting regulatory effects on oxidative stress and improving LPS-induced ALI.

Surface-Ligand Tuned Reversible Transformations in Aqueous Environments Between CdSe Magic-Size Clusters and Their Precursor Compounds.

That magic-size clusters (MSCs) have their counterpart precursor compounds (PCs) has not been generally accepted by expertise circles. Here, experimental evidence to support this new concept is presented. With aqueous-phase CdSe MSCs as a model system, it is shown that when the MSCs are dispersed in water containing a certain amount of L-cysteine (Cys), the MSCs disappear slowly. Upon the addition of CdCl2 , the MSCs recover. It is proposed that after dispersing, the MSCs transform to their quasi-isomeric, non-absorbing PCs upon Cys addition. In the presence of CdCl2 , the PCs transform back to the MSCs due to Cys elimination. The surface ligand Cys of the MSCs plays a significant role in the reversible transformations. The present study provides compelling evidence that absorbing MSCs have their non-absorbing PCs. The study findings suggest that the transformation between two MSCs that display absorption spectral shifts in a stepwise pattern is assisted by their PCs.

Precursor Compound-Assisted Formation of CdS Magic-Size Clusters in Aqueous Solutions.

Investigations of the formation pathway of semiconductor magic-size clusters (MSCs) in aqueous solutions are quite limited. Here, we present our understanding about a precursor compound (PC)-assisted formation pathway of aqueous-phase CdS MSCs exhibiting a characteristic absorption peak at about 360 nm (MSC-360). The reaction uses CdCl2 as the Cd source and thioglycolic acid (TGA) as both the S source and ligand in alkaline aqueous solutions. The mixture remains absorption featureless upon incubation at room temperature but with MSC-360 absorption observed upon adding butylamine. The longer the incubation period of the aqueous solution, the more MSC-360 forms after adding butylamine. We propose that Cd-TGA complexes form first, in which the TGA moieties then decompose partially to form PC of MSC-360 (PC-360) that cannot be observed in the optical absorption spectrum. The resulting PC-360 transforms to MSC-360 via quasi-isomerization in the presence of butylamine. The present study provides an in-depth understanding about the formation of aqueous-phase MSCs.

Mechanisms of the Higher Catalytic Activity of Polymer Forms over Complexes for Non-pyrolytic Mono-1,10-phenanthroline-Coordinated Cu2+ (Cu-N2 Type) in an Oxygen Reduction Reaction.

In this paper, we have thoroughly investigated the ORR mechanism of non-pyrolytic mono-1,10-phenanthroline-coordinated Cu2+ (Cu-N2 type) complexes and polymers by molecular dynamics and quantum mechanics calculation. In contrast to the complex-catalyzed ORR, which follows a direct four-electron pathway along intermediates of Cu(I)-Phen, the polymer-catalyzed ORR follows an indirect four-electron pathway by intermediates of Cu(II)-Phen. By analyzing the structure, spin population, electrostatic potential (ESP), and density of states, we confirmed that the higher ORR catalytic activity of the polymer is due to the conjugation effect of coplanar phenanthroline and Cu(II) in the planar reactants or at the base of the square-pyramidal intermediates. The conjugation effect allows the highest ESP to be located near the active center Cu(II), while the lower ESPs are distributed on the phenanthroline, which is very favorable for the reduction current. This will serve as a theoretical foundation for the development of new highly efficient ORR non-pyrolytic CuN2 polymer catalysts.

Development of an automatic sample changer with variable temperature for small-angle neutron scattering at China Spallation Neutron Source.

A small-angle neutron scattering (SANS) instrument at the China Spallation Neutron Source (CSNS) is an operating instrument for studying structures and inhomogeneities with dimensions ranging from 1 to 100 nm. Preparing multiple samples at once and measuring them sequentially is a common approach in SANS experiments to reduce neutron beamline wastes and increase experimental efficiency. We present the development of an automatic sample changer for the SANS instrument, including system design, thermal simulation, optimization analysis, structure design details, and temperature control test results. It features a two-row construction that can hold 18 samples on each row. The controllable temperature range is -30 to 300 °C. Furthermore, neutron scattering experiments on SANS at CSNS proved that this instrument has good temperature control performance and low background. This automatic sample changer is optimized for usage at SANS and will be offered to other researchers through the user program.

Direct and Indirect Evolution of Photoluminescent Semiconductor CdS Magic-Size Clusters through Their Precursor Compounds.

Colloidal semiconductor II-VI metal chalcogenide (ME) magic-size clusters (MSCs) exhibit either an optical absorption singlet or doublet. In the latter case, a sharp photoluminescence (PL) signal is observed. Whether the PL-inactive MSCs transform to the PL-active ones is unknown. We show that PL-inactive CdS MSC-322 transforms to PL-active CdS MSC-328 and MSC-373 in the presence of acetic acid (HOAc). MSC-322 displays a sharp absorption at ≈322 nm, whereas MSC-328 and MSC-373 both have broad absorptions respectively around 328 and 373 nm. In a reaction of cadmium myristate and S powder in 1-octadecene, MSC-322 develops; with HOAc, MSC-328 and MSC-373 are present. We propose that the MSCs evolve from their relatively transparent precursor compounds (PCs). The PC-322 to PC-328 quasi-isomerization involves monomer substitution, while monomer addition occurs for the PC-328 to PC-373 transformation. Our findings suggest that S dominates the precursor self-assembly quantitatively, and ligand-bonded Cd mainly controls MSC optical properties.

Chondroprotective Mechanism of Eucommia ulmoides Oliv.-Glycyrrhiza uralensis Fisch. Couplet Medicines in Knee Osteoarthritis via Experimental Study and Network Pharmacology Analysis.

Background: Knee osteoarthritis (KOA) is the primary prevalent disabling joint disorder among osteoarthritis (OA), and there is no particularly effective treatment at the clinic. Traditional Chinese medicine (TCM) herbs, such as Eucommia ulmoides Oliv. and Glycyrrhiza uralensis Fisch. (E.G.) couplet medicines, have been reported to exhibit beneficial health effects on KOA, exact mechanism of E.G. nevertheless is not fully elucidated. Purpose: We assess the therapeutic effects of E.G. on KOA and explore its underlying molecular mechanism. Methods: UPLC-Q-TOF/MS technique was used to analyze the active chemical constituents of E.G. The destabilization of the medial meniscus model (DMM) was employed to evaluate the chondroprotective action of E.G. in KOA mice using histomorphometry, µCT, behavioral testing and immunohistochemical staining. Additionally, network pharmacology and molecular docking were used to predict potential targets for anti-KOA activities of E.G., which was further verified through in vitro experiments. Results: In vivo studies have shown that E.G. could significantly ameliorate DMM-induced KOA phenotypes including subchondral bone sclerosis, cartilage degradation, gait abnormality and thermal pain reaction sensibility. E.G. treatment could also promote extracellular matrix synthesis to protect articular chondrocytes, which was indicated by Col2 and Aggrecan expressions, as well as reducing matrix degradation by inhibiting MMP13 expression. Interestingly, network pharmacologic analysis showed that PPARG might be a therapeutic center. Further study proved that E.G.-containing serum (EGS) could up-regulate PPARG mRNA level in IL-1ß-induced chondrocytes. Notably, significant effects of EGS on the increment of anabolic gene expressions (Col2, Aggrecan) and the decrement of catabolic gene expressions (MMP13, Adamts5) in KOA chondrocytes were abolished due to the silence of PPARG. Conclusion: E.G. played a chondroprotective role in anti-KOA by inhibiting extracellular matrix degradation, which might be related to PPARG.

Direct and Indirect Pathways of CdTeSe Magic-Size Cluster Isomerization Induced by Surface Ligands at Room Temperature.

The field of isomerization reactions for colloidal semiconductor magic-size clusters (MSCs) remains largely unexplored. Here, we show that MSCs isomerize via two fundamental pathways that are regulated by the acidity and amount of an incoming ligand, with CdTeSe as the model system. When MSC-399 isomerizes to MSC-422 at room temperature, the peak red-shift from 399 to 422 nm is continuous (pathway 1) and/or stepwise (pathway 2) as monitored in situ and in real time by optical absorption spectroscopy. We propose that pathway 1 is direct, with intracluster configuration changes and a relatively large energy barrier. Pathway 2 is indirect, assisted by the MSC precursor compounds (PCs), from MSC-399 to PC-399 to PC-422 to MSC-422. Pathway 1 is activated when PC-422 to MSC-422 is suppressed. Our findings unambiguously suggest that when a change occurs directly on a nanospecies, its absorption peak continuously shifts. The present study provides an in-depth understanding of the transformative behavior of MSCs via ligand-induced isomerization upon external chemical stimuli.

Exploration of the metabolic flexibility of glycogen accumulating organisms through metatranscriptome analysis and metabolic characterization.

Glycogen accumulating organisms (GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds supernatant of a reactor were decanted following the anaerobic period to enrich GAOs. Long-term monitoring demonstrated that the system was stable and exhibited typical characteristics of GAOs metabolism. Acetate was completely consumed after 60 min of the anaerobic phase. The level of glycogen decreased from 0.20 to 0.14 g/gSS during the anaerobic phase, whereas the level of glycogen significantly increased to 0.21g/gSS at the end of the aerobic period. Moreover, there was almost no phosphate release and absorption in the complete periods, thus confirming the successful construction of a GAOs enrichment system. Microbial community analysis demonstrated that Ca. Contendobacter was among the core functional genera and showed the highest activity among all of the communities. Furthermore, our study is the first to identify the involvement of the ethyl-malonyl-CoA pathway in the synthesis of polyhydroxyvalerate via croR, ccr, ecm, mcd, mch and mcl genes. The Embden-Meyerhof-Parnas (EMP) pathway was preferentially used via glgP. Furthermore, the glyoxylate cycle was the main source of ATP under anaerobic conditions, whereas the tricarboxylic acid cycle provided ATP under aerobic conditions. aceA and mdh appeared to be major modulators of the glyoxylate pathway for controlling energy flow. Collectively, our findings not only revealed the crucial metabolic mechanisms in a GAOs enrichment system but also provided insights into the potential application of Ca. Contendobacter for wastewater treatment.

Sepsis Due to Pandoraea sputorum Infection After Multiple Trauma in a Non-Cystic Fibrosis Patient: A Case Report from Southeast China.

Pandoraea sputorum (P. sputorum) infection is of great concern as these gram-negative bacillus species are multidrug-resistant and usually isolated from the patients' respiratory tract suffering from cystic fibrosis (CF). A few cases of infection have also been reported in non-CF patients due to its rare pathogenic nature with unclear and overlapping clinical, biochemical, and microbiological characteristics with other species. Here, we report an unusual case of a 46-year-old non-CF female, who presented with multiple pelvic fractures, acute traumatic brain injury, multiple rib fractures, and multiple burns (18% of the total body surface area, II°) by the collapse of a brick kiln, suffered from P. sputorum sepsis due to wound infection. Pandoraea species were isolated both from her blood and wound secretion. Antibiotic susceptibility testing indicated susceptibility to imipenem, tetracyclines, sulfamethoxazole, and ampicillin/sulbactam but resistance to meropenem, quinolones, aminoglycosides, and other beta-lactams. 16S ribosomal RNA (rRNA) PCR assays and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to confirm the bacteria as P. sputorum. After effective anti-infection of intravenous antibiotics (imipenem 1.0 Q8H with tigecycline 50 mg Q12H for 14 days), wound care, and other comprehensive treatment for two months, the patient improved and was discharged from the hospital eventually. After reviewing the literature, we observed that the susceptibility results of Pandoraea species were often multidrug-resistant and had a unique pattern of being resistant to meropenem but sensitive to imipenem. Biofilm formation, carbapenemase production, and unique gene procession differed from the environmental isolates could help explain its resistance. This case report highlights the potential virulence of Pandoraea species as a pathogen in patients with no underlying disease. Although they are often multi-resistant, imipenem can be a preferred treatment for Pandoraea species in the earliest identification steps.

Chemical Composition, Antitumor Properties, and Mechanism of the Essential Oil from Plagiomnium acutum T. Kop.

Plagiomnium acutum T. Kop. (P. acutum) has been used as a traditional Chinese medicine for thousands of years to treat cancer but lacks evidence. The objective of this work was to reveal the chemical composition of P. acutum essential oil (PEO) and explore its potential antitumor activity and molecular mechanism. PEO was prepared by the simultaneous distillation-extraction method and characterized by gas chromatography/mass spectroscopy. CCK8 assay, flow cytometry, western blot, and immunofluorescence techniques were used to analyze the effects and mechanism of PEO against cancer cells. A total of 74 constituents of PEO were identified, with diterpenes (26.5%), sesquiterpenes (23.89%), and alcohols (21.81%) being the major constituents. Two terpenoids, selina-6-en-4-ol and dolabella-3,7-dien-18-ol, were detected in PEO for the first time. PEO showed significant cell growth inhibitory activity on HepG2 and A549 cells by blocking the G1 phase and inducing apoptosis, which may be attributed to its upregulation of p21Cip1 and p27Kip1 proteins and interference with mitochondrial membrane potential effect. Dolabella-3,7-dien-18-ol accounts for 25.5% of PEO and is one of the main active components of PEO, with IC50 values in HepG2 and A549 cells of (25.820 ± 0.216) µg/mL and (23.597 ± 1.207) µg/mL, respectively. These results confirmed the antitumor medicinal value of P. acutum and showed great application potential in the pharmaceutical industry.

Processive binding mechanism of Cel9G from Clostridium cellulovorans: molecular dynamics and free energy landscape investigations.

The degradation of recalcitrant polysaccharides such as cellulose and chitin requires the synergistic functionality of processive glycosidase (GH) cocktails. Understanding the fundamental phenomenon of processivity is of biological and economic importance for the conversion of biomass into biofuel. In this work, cellulase family 9 from Clostridium cellulovorans (Cel9G), which is a processive endoglucanase, was used to elucidate the processive binding mechanism with respect to polysaccharides, since it exhibits a multimodular crystallographic structure. Metadynamics and molecular dynamics simulations were performed to explore the dynamics of cellulose chain binding to Cel9G via processive motion. The processive movement of the cellulose chain towards the catalytic domain may exhibit several local minima, which are related to strong CH/π interactions between the sugar rings and the aromatic residues distributed at the active site. For the binding of the G6 and G12 molecules, the energy barriers were determined to be 4.8 and 7.4 kcal mol-1, respectively. Based on the site-directed mutagenesis simulations of Y520A, it was found that the existence of Y520 is critical for processive binding. It is likely that Y520 and H125/Y416 form two anchor points to facilitate processive binding to polysaccharides. More importantly, the straight-line morphology of the substrate could be observed after the formation of the so-called slide mode, which is different from the V-shaped Michaelis complex structure revealed by quantum mechanics/molecular mechanics simulations. This indicates that an additional step, namely, catalytic activation, probably exists between processive binding and the hydrolysis reaction. Finally, a four-step catalytic cycle was proposed for Cel9G. Our work provides novel molecular-level insights into the structure-function relationship for the processive enzyme Cel9G and should aid the development of improved GH cocktails for the efficient cleavage of glycosidic linkages.

Transformations of Magic-Size Clusters via Precursor Compound Cation Exchange at Room Temperature.

The transformation of colloidal semiconductor magic-size clusters (MSCs) from zinc to cadmium chalcogenide (ZnE to CdE) at low temperatures has received scant attention. Here, we report the first room-temperature evolution of CdE MSCs from ZnE samples and our interpretation of the transformation pathway. We show that when prenucleation stage samples of ZnE are mixed with cadmium oleate (Cd(OA)2), CdE MSCs evolve; without this mixing, ZnE MSCs develop. When ZnE MSCs and Cd(OA)2 are mixed, CdE MSCs also form. We propose that Cd(OA)2 reacts with the precursor compounds (PCs) of the ZnE MSCs but not directly with the ZnE MSCs. The cation exchange reaction transforms the ZnE PCs into CdE PCs, from which CdE MSCs develop. Our findings suggest that in reactions that lead to the production of binary ME quantum dots, the E precursor dominates the formation of binary ME PCs (M = Zn or Cd) to have similar stoichiometry. The present study provides a much more profound view of the formation and transformation mechanisms of the ME PCs.

Manipulating Reaction Intermediates to Aqueous-Phase ZnSe Magic-Size Clusters and Quantum Dots at Room Temperature.

It is not resolved which model describes better the aqueous-phase nucleation and growth of semiconductor quantum dots (QDs), the classical one-step one or the nonclassical multi-step one. Here, we design a room-temperature reaction to trap reaction intermediates in the prenucleation stage of ZnSe QDs (as a model system). We show that the trapped intermediate can transform to magic-size clusters (MSCs) via intra-molecular reorganization and can fragment to enable the growth of QDs. The MSCs exhibit a sharp optical absorption peaking at 299 nm, labelled MSC-299. The intermediate, the precursor compound (PC-299) of MSC-299, is optically transparent at 299 nm and to longer wavelengths. This intermediate forms in various Zn and Se reaction systems. The present study provides unambiguous evidence that the nonclassical and classical pathways are both necessary to explain the nucleation and growth of aqueous-phase QDs, with the former pathway favored more by high reaction concentrations.

Ruthenium-Catalyzed Divergent Acceptorless Dehydrogenative Coupling of 1,3-Diols with Arylhydrazines: Synthesis of Pyrazoles and 2-Pyrazolines.

Herein, the divergent transformations of 1,3-diols with arylhydrazines via acceptorless dehydrogenative coupling reactions to selectively synthesize pyrazoles and 2-pyrazolines were reported, which were based on Ru3(CO)12/NHC-phosphine-phosphine catalytic systems. The reactions featured low catalyst loading, high selectivity, wide substrate scope, and good yields, with only water and hydrogen gas (H2) as the byproducts.

Ethylmalonyl-CoA pathway involved in polyhydroxyvalerate synthesis in Candidatus Contendobacter.

Here a stable glycogen accumulating organisms (GAOs) system was operated by anaerobic-aerobic mode in the sequencing batch reactor. We focused on the metabolic mechanisms of PHAs storage from GAOs. Our system showed the classic characteristic of glycogen accumulating metabolism (GAM). Glycogen consumption was followed by acetic acid uptake to synthesize poly-ß-hydroxyalkanoates (PHAs) during the anaerobic period, and glycogen was synthesized by PHAs degradation in the aerobic stage. Microbial community structure indicated that Candidatus Contendobacter was the most prevalent GAOs. We found that the ethylmalonyl-CoA (EMC) pathway was the crucial pathway supplying the core substance propionyl-CoA for poly-ß-hydroxyvalerate (PHV) synthesis in Candidatus Contendobacter. All genes in EMC pathway were mainly located in Candidatus Contendobacter by gene source analysis. The key genes expression of EMC pathway increased with Candidatus Contendobacter enrichment, further validating that propionyl-CoA was synthesized by Candidatus Contendobacter predominantly via EMC pathway. Our work revealed the novel mechanisms underlying PHV synthesis through EMC pathway and further improved the intercellular storage metabolism of GAOs.

Characterization of Three Paris polyphylla Glycosyltransferases from Different UGT Families for Steroid Functionalization.

Plant steroid glycosides, such as phytosterol glycosides, steroidal saponins, and steroidal glycoalkaloids, are natural products with great pharmaceutical values. In this study, we characterized three UDP-glycosyltransferases (UGTs) involved in the glycosylation of steroidal sapogenin from Paris polyphylla. Substrate specificity analysis revealed that UGT73CR1 could glycosylate steroidal sapogenins and steroidal alkaloids, with the highest affinity for diosgenin. The residues His27 and Asp129 of UGT73CR1 are conserved in corresponding positions of plant glycosyltransferases, which are crucial for activating the C-3 OH of the receptor substrates. In comparison, UGT80A33 and UGT80A34 exhibited a higher affinity for cholesterol than other steroids. UGT80s have a larger active pocket, which allows them to accommodate the side chain of sterols. In summary, we assessed three P. polyphylla glycosyltransferases from two UGT families for the functionalization of steroidal molecules, which will provide a basis for the future biomanufacturing of diverse bioactive steroid glycosides.