Acetylenic spiroketal enol ethers from Artemisia rupestris and their synergistic antibacterial effects on methicillin-resistant Staphylococcus aureus.

Synergistic bioassay-guided isolation of the extracts of Artemisia rupestris L, which belongs to the family Asteraceae, afforded two acetylenic spiroketal enol ethers, namely rupesdiynes A (1) and B (2). Their structures were determined based on spectroscopic analysis and experimental and calculated ECD investigations. The two compounds exhibited synergistic activity and were able to reduce the minimum inhibitory concentration (MIC) of oxacillin four-fold, with a fractional inhibitory concentration index (FICI) of 0.5 in combination with oxacillin against the oxacillin-resistant EMRSA-16. Biofilm formation inhibitory and Ethidium bromide (EtBr) efflux assay were further employed to verify the possible mechanism of the synergistic antibacterial effect. Additionally, molecular docking studies were conducted to investigate the binding affinities of the two compounds with penicillin-binding protein 2a (PBP2a) of EMRSA-16. Taken together, rupesdiynes A (1) and rupesdiyne B (2) showed moderate synergistic activity against EMRSA-16 with oxacillin via inhibiting biofilm formation and efflux pump activity, respectively.

Bulk and single-cell alternative splicing analyses reveal roles of TRA2B in myogenic differentiation.

Alternative splicing (AS) disruption has been linked to disorders of muscle development, as well as muscular atrophy. However, the precise changes in AS patterns that occur during myogenesis are not well understood. Here, we employed isoform long-reads RNA-seq (Iso-seq) and single-cell RNA-seq (scRNA-seq) to investigate the AS landscape during myogenesis. Our Iso-seq data identified 61,146 full-length isoforms representing 11,682 expressed genes, of which over 52% were novel. We identified 38,022 AS events, with most of these events altering coding sequences and exhibiting stage-specific splicing patterns. We identified AS dynamics in different types of muscle cells through scRNA-seq analysis, revealing genes essential for the contractile muscle system and cytoskeleton that undergo differential splicing across cell types. Gene-splicing analysis demonstrated that AS acts as a regulator, independent of changes in overall gene expression. Two isoforms of splicing factor TRA2B play distinct roles in myogenic differentiation by triggering AS of TGFBR2 to regulate canonical TGF-ß signalling cascades differently. Our study provides a valuable transcriptome resource for myogenesis and reveals the complexity of AS and its regulation during myogenesis.

A novel off-line multi-dimensional high-speed countercurrent chromatography strategy for preparative separation of bioactive neolignan isomers from Piper betle. L.

Separation and purification of naturally occurring isomers from herbs are still challenging. High-speed counter-current chromatography (HSCCC) has been applied to isolate natural products. In this study, an off-line multi-dimensional high-speed counter-current chromatography (multi-D HSCCC) strategy was developed utilizing the in situ concentration technique with online storage recycling elution to rapidly separate bioactive isomeric neolignans from chloroform-partitioned samples of the plant Piper betle L. In the procedure, the crude sample (105 mg) was implemented using the online storage recycling technique in a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water (7: 5: 12: 3), which first simply afforded a neolignane kadsurenone (1, 5.3 mg) and its epimer (-)-denudatin B (2, 6.4 mg). Then, the remains fr a was subjected to the second-dimensional HSCCC elution using the in situ concentration technique with online storage recycling technique in another solvent system of petroleum ether-ethyl acetate-methanol-water (5: 5: 11, 15). As a result, kadsurenin I (3, 0.6 mg) and its regioisomer pibeneolignan C (4, 5.0 mg), together with the fractional remaining fr b and fr c, were obtained. Thirdly, the fr c was reloaded to allow the HSCCC for recycling elution with the former solvent system employing the in situ concentration strategy and yielded a pair of epimers, (7R,8S,1'S)-1'-allyl-5-methoxy-8-methyl-7-piperonyl-7,8,3,6-tetrahydro-2-oxobenzofuran (5, 10.2 mg), and 3-epi-(-)-burchullin (6, 2.6 mg). Finally, the three pairs of less amount and the structurally similar isomers 1-6 were isolated from the crude fraction of P. betle with a high HPLC purity of over 95.0 % for compound 2, 4-6 and 92.5 % for compound 1, 91.0 % for 3, while the purity of 1 and 3 in 1H NMR were 89.9 % and 91.1 %, respectively. The whole isolation process was quick and efficient. Compounds 1, 2, 4 and 5 showed significantly synergistic activities combining several antibiotics against five drug-resistant Staphylococcus aureus with FICIs from 0.156 to 0.375. This novel off-line multi-dimensional HSCCC strategy could be broadened to application for the rapid separation of complex natural products.

The ubiquitin specific protease 7 stabilizes HPV16E7 to promote HPV-mediated carcinogenesis.

Human papillomavirus (HPV) encoded E7 oncoprotein plays an important role in supporting the viral productive cycle and inducing cancer phenotypes. The ability of E7 to exercise these functions, partly, depends upon its steady-state level. HPV manipulates the host de-ubiquitination pathway to maintain the stability of its viral proteins. In this study, we uncovered that HPV interacts with the host ubiquitin specific protease 7 (USP7), a universal de-ubiquitinating enzyme, leading to the stabilization of E7 oncoprotein. We observed that HPV16E7 complexes with USP7 via the E7-CR3 domain, and this E7-USP7 complex exists predominantly in the nucleus. Our results showed that USP7 stabilizes and prolongs the half-life of HPV16E7 by antagonizing ubiquitination and proteasomal degradation. Consistently, when we inhibited USP7 activity using HBX 19818, HPV16E7 protein level was reduced and its turnover was increased. We also provide evidence that HBX 19818-induced USP7 inhibition can halt HPV-mediated carcinogenesis, including cell proliferation, invasion, migration and transformation. These findings indicate that USP7 plays an essential role in stabilizing E7. The specific and potent inhibitory effects of HBX 19818 on HPV-induced carcinogenesis provide a molecular insight, suggesting the potential of targeting USP7 as a new therapeutic approach for the treatment of HPV-associated cancers.

Natural Product BO-1 as an Inner Responsive Molecule Inhibits Antimicrobial-Resistant Staphylococcus aureus via Synergism.

Multidrug-resistant Staphylococcus aureus, a Gram-positive bacterium that causes several difficult-to-treat human infections, is a considerable threat to global healthcare. We hypothesize that there exist inner responsive molecules (IRMs) which can function synergistically with antibiotics to restore the sensitivity of resistant bacteria to existing antibiotics without inducing new antibiotic resistance. An investigation of the extracts of the Chinese medicinal herb Piper betle L. led to the isolation of six benzoate esters, BO-1-BO-6. Among these, BO-1 as a distinct IRM displayed considerable synergism by potentiating antibacterial activity against five antibiotic-resistant S. aureus strains. Mechanistic studies demonstrated that BO-1 acted as a suppressing drug resistance IRM via inhibiting efflux activity. A combination of BO-1 with ciprofloxacin significantly inhibited resistance to this antibiotic and reversed its resistance in the S. aureus strain. Furthermore, BO-1 effectively enhanced the activity of ciprofloxacin against the efflux fluoroquinolone-resistant S. aureus strain SA1199B that caused infection in two animal models and significantly decreased the inflammatory factors IL-6 and C-reactive protein of the infected mice, thereby showing the practice utility of this approach.

Interaction between Human Papillomavirus-Encoded E6 Protein and AurB Induces Cell Immortalization and Proliferation-A Potential Target of Intervention.

The human papillomavirus E6 and E7 oncoproteins interact with a different subset of host proteins, leading to dysregulation of the apoptotic, cell cycle, and signaling pathways. In this study, we identified, for the first time, that Aurora kinase B (AurB) is a bona fide interacting partner of E6. We systematically characterized the AurB-E6 complex formation and its consequences in carcinogenesis using a series of in vitro and cell-based assays. We also assessed the efficacy of Aurora kinase inhibitors in halting HPV-mediated carcinogenesis using in vitro and in vivo models. We showed that AurB activity was elevated in HPV-positive cells, and this correlated positively with the E6 protein level. E6 interacted directly with AurB in the nucleus or mitotic cells. A previously unidentified region of E6, located upstream of C-terminal E6-PBM, was important for AurB-E6 complex formation. AurB-E6 complex led to reduced AurB kinase activity. However, the AurB-E6 complex increased the hTERT protein level and its telomerase activity. On the other hand, AurB inhibition led to the inhibition of telomerase activity, cell proliferation, and tumor formation, even though this may occur in an HPV-independent manner. In summary, this study dissected the molecular mechanism of how E6 recruits AurB to induce cell immortalization and proliferation, leading to the eventual cancer development. Our findings revealed that the treatment of AZD1152 exerted a non-specific anti-tumor effect. Hence, a continuous effort to seek a specific and selective inhibitor that can halt HPV-mediated carcinogenesis should be warranted.

E6-Encoded by Cancer-Causing Human Papillomavirus Interacts with Aurora Kinase A To Promote HPV-Mediated Carcinogenesis.

The expression of human papillomavirus (HPV) oncoproteins perturbed multiple cellular events of the host cells, leading to the formation of cancer phenotypes. Our current and previous studies indicated that Aurora kinase A (AurA), a mitotic regulator that is often aberrantly expressed in human cancers, is preferentially bound to E6-encoded by cancer-causing HPV. AurA is believed to be important for the proliferation and survival of HPV-positive cells. Nonetheless, the interaction between AurA and E6, and the mechanism of how this association is involved in carcinogenesis, have not been elucidated clearly. Hence, we performed a series of biochemical assays to characterize the AurA-E6 association and complex formation. We found the C-terminus of E6, upstream of the PDZ binding motif of E6, is important to forming the AurA-E6 complex in the nucleus. We also showed that the expression level of E6 corresponded positively with AurA expression. Meanwhile, the functional consequences of the AurA-E6 association to AurA kinase function and host cellular events were also delineated. Intriguingly, we revealed that AurA-E6 association regulated the expression of cyclin E and phosphor-Histone H3, which are involved in G1/S and mitotic phases of the cell cycle, respectively. Depletion of AurA also reduced the invasive ability of HPV-positive cells. AurA inhibition may not be sufficient to reduce the oncogenic potential exerted by E6. Altogether, our study unleashed the mechanism of how HPVE6 deploy AurA to promote cancer phenotypes, particularly through dysregulation of cell cycle checkpoints and suggests that the AurA-E6 complex possesses a therapeutic value. IMPORTANCE We unveiled the mechanism of how HPV employs Aurora kinase A (AurA) of host cells to exert its oncogenic capability synergistically. We systematically characterized the mode of interaction between E6-encoded by cancer-causing HPV and AurA. Then, we delineated the consequences of AurA-E6 complex formation on AurA kinase function and changes to cellular events at molecular levels. Using a cell-based approach, we unleashed that disruption of AurA-E6 association can halt cancer phenotype exhibited by HPV-positive cancer cells. Our findings are vital for the designing of state-of-the-art therapies for HPV-associated cancers.

Review of the Standard and Advanced Screening, Staging Systems and Treatment Modalities for Cervical Cancer.

Cancer arising from the uterine cervix is the fourth most common cause of cancer death among women worldwide. Almost 90% of cervical cancer mortality has occurred in low- and middle-income countries. One of the major aetiologies contributing to cervical cancer is the persistent infection by the cancer-causing types of the human papillomavirus. The disease is preventable if the premalignant lesion is detected early and managed effectively. In this review, we outlined the standard guidelines that have been introduced and implemented worldwide for decades, including the cytology, the HPV detection and genotyping, and the immunostaining of surrogate markers. In addition, the staging system used to classify the premalignancy and malignancy of the uterine cervix, as well as the safety and efficacy of the various treatment modalities in clinical trials for cervical cancers, are also discussed. In this millennial world, the advancements in computer-aided technology, including robotic modules and artificial intelligence (AI), are also incorporated into the screening, diagnostic, and treatment platforms. These innovations reduce the dependence on specialists and technologists, as well as the work burden and time incurred for sample processing. However, concerns over the practicality of these advancements remain, due to the high cost, lack of flexibility, and the judgment of a trained professional that is currently not replaceable by a machine.

Neolignans from Piper betle Have Synergistic Activity against Antibiotic-Resistant Staphylococcus aureus.

A phytochemical investigation of an extract of the leaves of Piper betle, guided by a synergistic antibacterial screen, led to the isolation and structural elucidation of 10 new neolignans, Pibeneolignan A-J (1-10), together with 11 known compounds. The structures and absolute configurations of the new compounds were elucidated on the basis of spectroscopic data, single-crystal X-ray diffraction analysis, and experimental and calculated ECD investigations. Compounds 1 and 2 are new naturally occurring neolignan skeletons, based on the cyclohept-2-ene-1,4-dione framework. We propose that these natural products are biosynthetically formed from bicyclic [3.2.1] neolignans by oxidative cleavage and ring opening at C-1' and C-2'. Among these compounds, 9, 13, 15, and 16, in combination with norfloxacin against an effluxing S. aureus strain (SA1199B), exhibited significant synergistic activity with fractional inhibitory concentration indices (FICIs) of 0.078, 0.156, 0.125, and 0.25, respectively. Bacterial growth curves, ethidium bromide (EtBr) efflux, and qRt-PCR were further employed to verify their synergistic antibacterial mechanism. Furthermore, computational molecular modeling suggested the binding of compounds 14-17 and 19 to the active site of the modeled structure of the NorA efflux pump, which is the main efflux pump in SA1199B.

The Phytochemistry and Pharmacology of Hypericum.

Hypericum L. is a genus of the family Hypericaceae within the dicotyledones. The constituents of Hypericum species are valued for their important biological properties. Their use is in the treatment of depression and as antibacterial agents has been well documented in the primary literature and in ethnobotanical reports. The present contribution gives a comprehensive summary of the chemical constituents of members of the genus Hypericum and their biological effects. A detailed account of the chemical constituents, including phloroglucinol derivatives, xanthones, dianthrones, and flavonoids, is included. These compounds show a diverse range of biological activities that include antimicrobial, cytotoxic, antidepressant-like, and antinociceptive effects.

Theoretically designed two-dimensional γ-C4O as an effective gas separation membrane for hydrogen purification.

A high-performance gas separation membrane for hydrogen (H2) purification is still highly desirable for the sustainable development of our society. Based on the structure of γ-graphyne, we theoretically designed the two-dimensional nanomaterials γ-C4X (X = O, S or Se) with intrinsic pores that may be suitable for gas separation. By first-principles calculations, we obtained the geometric structures of γ-C4X, and confirmed that γ-C4O and γ-C4S are stable at room temperature. Due to the moderate size of the intrinsic pores, γ-C4O exhibits a lower diffusion barrier and higher permeance for H2 than those of γ-C4S. It is worth noting that at room temperature, the high selectivity (1019) for separating H2 from a H2/CH4 mixture by γ-C4O shows great potential for H2 purification. Moreover, the classic molecular dynamics simulations at 300 K demonstrate that H2 can easily permeate through the intrinsic pores of γ-C4O membranes with high permeability and selectivity, which supports our first-principles calculations.

Mechanical, Electronic, and Magnetic Properties of NiX2 (X = Cl, Br, I) Layers.

Since the recent experimental discovery of the CrI3 and CrGeTe3 monolayers, van der Waals (vdW) layered transition metal compounds have been recognized as promising candidates to realize 2D ferromagnetic (FM) semiconductors. However, until now, only limited compounds have been proposed to be ferromagnetic semiconductors. Here, on the basis of first-principles calculations, we report that the monolayer, Janus monolayer, and bilayer of NiX2 (X = Cl, Br, I) are intrinsic 2D FM semiconductors. Our results show that exfoliation energy of the NiX2 monolayer is smaller than that of graphene, and all studied NiX2 layers show semiconducting band gaps. The predicted Curie temperature values for NiX2 (X = Cl, Br, I) monolayers ranged from 120 to 170 K with Monte Carlo simulations. For the Janus monolayer, we found that the spin interaction shows a very strong magnetoelectric coupling under an external electric field. Furthermore, for the bilayer of NiX2, our results show that the interlayer coupling is quite weak, indicating the possibility of tuning the magnetic coupling through external manipulations.

Confinement boosts CO oxidation on an Ni atom embedded inside boron nitride nanotubes.

To date, most studies of heterogeneous catalysis have focused on metal particles supported on the surface of substrates. However, studies of the catalytic properties of metallic nanoparticles supported on the interior surface of nanotubes are rare. Using first-principles calculations based on density functional theory, we have studied the CO oxidation on a single nickel atom confined in a nitrogen vacancy on the inside surface of boron nitride nanotubes (BNNT). By exploring the Eley-Rideal mechanism, we find that an Ni atom embedded on the interior surface of BNNTs exhibits a much higher catalytic activity for CO oxidation when compared with Ni doped on their outside surface. In addition, the energy barriers of the rate-determining step for CO oxidation on Ni embedded on the inside wall of BNNT(5,5), BNNT(6,6) and BNNT(7,7) are 0.39, 0.29 and 0.33 eV, respectively. The results illustrate the merit of confinement for CO oxidation.

Ar plasma irradiation improved optical and electrical properties of TiO2/Ag/TiO2 multilayer thin film.

Embedding a thin metal layer between two thin dielectric or semiconductor layers [dielectric/metal/dielectric (DMD)] leads to a kind of transparent electrode that is promising as a substitute for the currently widely applied indium tin oxide electrode. However, the optical and electrical properties of DMD still wait for further improvement. In this study, Ar plasma irradiation (API) was, for the first time to our knowledge, applied to improve the optical and electrical properties of a TiO2/Ag/TiO2 electrode that was fabricated by electron-beam evaporation of TiO2 and electric-resistance heating of high purity Ag under vacuum. Ar plasma was produced by radio frequency glow discharge. The Ag layer was bombarded before the second layer of TiO2 was deposited. The electrode with configuration of TiO2 (24 nm)/Ag(14 nm)/TiO2 (24 nm) after API for 10 s shows excellent performance. The mean transmittance between 370 and 800 nm reaches 94% and the sheet resistance is as low as 6 Ω/sq, while Haacke's figure of merit is as high as 112×10(-3) Ω(-1). The improvement mechanism is discussed based on field emission scanning electron microscope images and absorption spectra. The improvement is attributed to the fact that API reduces the localized surface plasmon resonance of Ag nanoparticles and makes the Ag film thinner and denser.

[Effect of Parasep® feces centrifuge tube method on detecting schistosome eggs].

OBJECTIVE: To evaluate the effect of the Parasep® feces centrifuge tube method on detecting schistosome eggs. METHODS: A total of 803 residents aged from 6-65 years were selected in 2 schistosomiasis endemic villages, Jiangling County, Hubei Province, and their stool samples were collected and detected parallelly by the Kato-Katz technique, nylon silk egg hatching method, and Parasep® feces centrifuge tube method at the same time. RESULTS: Among the 803 people, 15 cases were found of schistosome egg positive, and the positive rate was 1.87%. The positive rates of the Kato-Katz technique, nylon silk egg hatching method, and Parasep® feces centrifuge tube method were 0.75%, 1.49% and 1.12%, respectively. The schistosome eggs got with the Parasep® feces centrifuge tube method were clear and easy to identify. CONCLUSION: In low endemic areas of schistosomiasis, the Parasep® feces centrifuge tube method can be used as schistosomiasis japonica etiology diagnosis method.

A promising monolayer membrane for oxygen separation from harmful gases: nitrogen-substituted polyphenylene.

We theoretically demonstrate that N-substitutional doping dramatically reduces the diffusion barrier for oxygen passing through the pores of polyphenylene, leading to a massive enhancement in O2 selectivity over various harmful gases with excellent permeance at appropriate temperatures for O2 across an N-doped polyphenylene in a unit cell.

Theoretical study of CO oxidation on cationic, neutral, and anionic AuM dimers (M = Pd and Ag).

The CO and O2 adsorption as well as CO oxidation on cationic, neutral, and anionic AuM dimers (M = Pd, Ag) are studied by density functional calculations. Our results show that CO and O2 are adsorbed more stably on AuPd dimers than on AuAg dimers with corresponding charge state. O2 is favorable to be adsorbed on Pd atom in AuPd(+), AuPd and AuPd(-) dimers. CO is adsorbed on Pd in AuPd and AuPd(-), while it is favorable to be adsorbed on Au in AuPd(+). For AuAg dimers, O2 is adsorbed on Ag in AuAg and AuAg(-), and it is adsorbed on Au in AuAg(+). CO is adsorbed on Ag in AuPd(-), while it is adsorbed on Au in AuAg and AuAg(+). The CO oxidation reaction is explored along two possible pathways: path-1 involves CO attacking the initial complexes of AuM dimers and O2, and path-2 is related to O2 interacting with the complexes of AuM dimers and CO. The charge state of AuM dimers has a substantial effect on CO oxidation. The reaction on AuPd(-) prefers path-1, and AuPd(+) mediated reaction proceeds along path-2, while CO oxidation on AuPd is difficult along both paths. For AuAg, both pathways are viable for AuAg(-) mediated reactions, while AuAg and AuAg(+) mediated reactions prefer path-2. Moreover, the energy barriers of CO oxidation on neutral AuAg is comparable with those on AuPd in all charge states while the energy barriers for AuAg(-) and AuAg(+) are considerably lower than those for all AuPd dimmers, indicating the impurity atom also plays a significant role in the catalytic activity. Furthermore, AuAg(-) is proposed to be the most active species due to the lowest barrier involved in the reaction.

A B-C-N hybrid porous sheet: an efficient metal-free visible-light absorption material.

The polyphenylene network, known as porous graphene, is one of the most important and widely studied two-dimensional materials. As a potential candidate for photocatalysis and photovoltaic energy generation, its application has been limited by the low photocatalytic activity in the visible-light region. State-of-the-art hybrid density functional theory investigations are presented to show that an analogous B-C-N porous sheet outperforms the pristine polyphenylene network with significantly enhanced visible-light absorption. Compared with porous graphene, the calculated energy gap of the B-C-N hybrid crystal shrinks to 2.7 eV and the optical absorption peak remarkably shifts to the visible light region. The redox potentials of water splitting are well positioned in the middle of the band gap. Hybridizations among B_p, N_p and C_p orbitals are responsible for these findings. Valence and conduction band calculations indicate that the electrons and holes can be effectively separated, reducing charge recombination and improving the photoconversion efficiency. Moreover, the band gap and optical properties of the B-C-N hybrid porous sheet can be further finely engineered by external strain.

Boron-substituted graphyne as a versatile material with high storage capacities of Li and H2: a multiscale theoretical study.

Based on density functional theory (DFT), first-principles molecular dynamics (MD), and the grand canonical ensemble Monte Carlo (GCMC) method, we investigated the boron substitution in aromatic rings of graphyne in terms of geometric and electronic structures as well as its bifunctional application including Li and H2 storage. The calculated binding energies of B-doped graphyne (BG) are significantly enhanced at two adsorptive sites compared to pristine graphyne, leading to high lithiation potentials of 2.7 V in 6Li@1BG, and even higher with 3.0 V in 6Li@3BG. Thus, 6Li@1BG with a capacity of 1125 mA h g(-1), which is much larger than other carbon materials, is proposed to be a good anode material in lithium-ion batteries. For further hydrogen storage in 6Li@nBG, the results show that it can steadily adsorb at least 8H2 in DFT, MD and GCMC computations, and the excess gravimetric H2 uptake is 7.4 wt% at ambient conditions, exceeding the 2017 DOE target. Our multiscale simulations demonstrate that chemical modifications in two-dimensional carbon structures are very promising for high lithium storage and hydrogen uptake.

The strain effect on colossal oxygen ionic conductivity in nanoscale zirconia electrolytes: a first-principles-based study.

Density functional theory calculations and first-principles molecular dynamics (MD) simulations have been performed to examine the strain effect on the colossal oxygen ionic conductivity in selected sandwich structures of zirconia electrolytes. For the KTaO(3)/YSZ/KTaO(3) sandwich structure with 9.7% lattice mismatch, transition state calculations indicate that the strain effect changes the oxygen migration pathways from straight line into zigzag form and reduces the energy barrier by 0.2 eV. On the basis of our computational results, a possible oxygen ion diffusion highway is suggested. By finite-temperature MD simulations, an activation barrier of 0.33 eV is obtained, corresponding to an oxygen ionic conductivity which is 6.4 × 10(7) times higher than that of the unstrained bulk zirconia at 500 K. A nearly linear relationship is identified between the energy barrier and the lattice mismatch in the sandwich structures.