Mechanisms of Antibiotic Resistance and Developments in Therapeutic Strategies to Combat Klebsiella pneumoniae Infection.

Infections with drug-resistant bacteria have become one of the greatest public health challenges, and K. pneumoniae is among the top six drug-resistant bacteria. K. pneumoniae often causes nosocomial infections, leading to illnesses such as pneumonia, liver abscesses, soft tissue infections, urinary tract infections, bacteremia, and in some cases death. As the pathogen continues to evolve and its multidrug resistance increases, K. pneumoniae poses a direct threat to humans. Drug resistance in K. pneumoniae may occur due to the formation of biofilms, efflux pumps, and the production of ß-lactamases. In many cases, resistance is further enhanced by enzymatic modification and loss of porins. Drug resistance to K. pneumoniae has led to a decline in the effectiveness of conventional therapies against this pathogen. Therefore, there is an urgent need to accelerate the development of new antibiotics and explore new therapeutic approaches such as antimicrobial peptides, phages, traditional Chinese medicine, immunotherapy, Antimicrobial nanoparticle technology, antisense oligonucleotides and gene editing technologies. In this review, we discuss the mechanisms of drug resistance in K. pneumoniae and compare several new potential therapeutic strategies to overcome drug resistance in the treatment of K. pneumoniae infections.

Characteristics of antibiotic resistance mechanisms and genes of Klebsiella pneumoniae.

Klebsiella pneumoniae is an important multidrug-resistant (MDR) pathogen that can cause a range of infections in hospitalized patients. With the growing use of antibiotics, MDR K. pneumoniae is more prevalent, posing additional difficulties and obstacles in clinical therapy. To provide a valuable reference to deeply understand K. pneumoniae, and also to provide the theoretical basis for clinical prevention of such bacteria infections, the antibiotic resistance and mechanism of K. pneumoniae are discussed in this article. We conducted a literature review on antibiotic resistance of K. pneumoniae. We ran a thorough literature search of PubMed, Web of Science, and Scopus, among other databases. We also thoroughly searched the literature listed in the papers. We searched all antibiotic resistance mechanisms and genes of seven important antibiotics used to treat K. pneumoniae infections. Antibiotics such as ß-lactams, aminoglycosides, and quinolones are used in the treatment of K. pneumoniae infection. With both chromosomal and plasmid-encoded ARGs, this pathogen has diverse resistance genes. Carbapenem resistance genes, enlarged-spectrum ß-lactamase genes, and AmpC genes are the most often ß-lactamase resistance genes. K. pneumoniae is a major contributor to antibiotic resistance worldwide. Understanding K. pneumoniae antibiotic resistance mechanisms and molecular characteristics will be important for the design of targeted prevention and novel control strategies against this pathogen.

Study on Synergistic Anti-Inflammatory Effect of Typical Functional Components of Extracts of Ginkgo Biloba Leaves.

There are some differences in the anti-inflammatory activities of four typical components in EGB (extracts of ginkgo biloba leaves), and there is also a synergistic relationship. The order of inhibiting the NO-release ability of single functional components is OA > GF > OPC > G. Ginkgolide (G), proanthocyanidins (OPC), and organic acids (OA) all have synergistic effects on ginkgo flavonoids (GF). GF:OA (1:9) is the lowest interaction index among all complexes, showing the strongest synergy. The anti-inflammatory mechanism of the compound affects the expression of p-JNK, p-P38, and p-ERK1/2 proteins by inhibiting the expression of iNOS and COX2 genes on NFKB and MAPK pathways. This also provides a research basis for the development of anti-inflammatory deep-processing products of EGB.

Atractylenolide III suppresses senescence-associated secretome via inhibiting cGAS/NF-κB pathway in hepatic stellate cells.

Senescence of activated hepatic stellate cells (aHSCs) is a stable growth arrest that is implicated in liver fibrosis regression. Senescent cells often accompanied by a multi-faceted senescence-associated secretory phenotype (SASP). Induction of aHSCs senescence by inhibiting SASP may be a potential therapeutic model against hepatic fibrosis. To evaluate the role of atractylenolide III (ATR III) in the development of chemotherapeutic drug-induced SASPs in hepatic stellate cells. Etoposide-induced senescent HSC-LX2 model was established and treated with ATR III at different concentrations (20, 30 and 40 µM). We found that ATR III dose-dependently enhanced senescence in etoposide-induced LX2 cells. ATR III dose-dependently decreased the release and expression of SASP factors (interleukin [IL]-1α, IL-1ß, IL6 and IL-8) in senescent cells. ATR III regulated cyclic GMP-AMP synthase (cGAS)/nuclear factor κ (NF-κB) signalling to affect SASP expression in senescent cells. The addition of 2'3' cGAMP counteracted the effect of ATR III. The release of SASP factors in the conditioned medium from senescent cells could affect cell migration, proliferation and contraction through paracrine manner. Our results indicated ATR III could still enter senescence and prevent the production of SASP and its paracrine effects in senescent cells, an effect that may be related to the possible inhibition of cGAS/NF-κB signalling by ATR III. Our study proves that ATR III may be an effective potential drug against liver fibrosis by promoting aHSC senescence, which can provide a new choice for the future clinical treatment of liver fibrosis.

Network Pharmacology Analysis and Experimental Verification on Antiangiogenesis Mechanism of Hedyotis diffusa Willd in Liver Cancer.

Purpose: Hedyotis diffusa Willd (HDW) is one of the most well-known herbs used in the therapy of cancer. However, the potential mechanisms of its antiangiogenic effects have not been fully explored. Here, we applied a network pharmacology approach to explore the potential mechanisms of HDW against liver cancer angiogenesis (LCA) and used a mouse orthotopic liver cancer model for experimental verification accordingly. Methods: The effective components, primary active compounds, and possible targets in the therapy of LCA were predicted using network pharmacology and bioinformatics. In vivo testing of the pharmacodynamic foundation of HDW in the treatment of LCA was performed. Hepa1-6 cells were implanted in C57BL/6 mice to establish an orthotopic liver cancer model to evaluate the antitumor and antiangiogenesis effects of the drug. Furthermore, protein levels were evaluated by western blotting, immunofluorescence, and immunohistochemistry. Results: We firstly confirmed the therapeutic effect of HDW on LCA and subsequently screened 7 active compounds from HDW according to their pharmacokinetic properties. Network analysis and enrichment analysis indicated that these compounds exhibit antiangiogenic effect by acting on multiple targets and thereby regulating multiple pathways mainly involved in Akt1, IL-6, IL-1ß, IL-17, hypoxia inducible factor-1α (HIF-1α), and tumor necrosis factor-α (TNF-α). Importantly, we preliminarily verified the results of the network pharmacology analysis in vivo. Conclusion: Collectively, our work initially explored the therapeutic mechanism of HDW on tumor angiogenesis, which lays an experimental reference for further exploring its pharmacological action and its clinical application.

Polygonatum sibiricum Polysaccharides Attenuate Lipopoly-Saccharide-Induced Septic Liver Injury by Suppression of Pyroptosis via NLRP3/GSDMD Signals.

Sepsis is a systemic inflammatory response syndrome with high mortality. Acute liver injury is an independent predictor for poor prognosis in septic patients. Polygonatum sibiricum polysaccharides (PSP) have been reported to possess anti-inflammatory and hepatoprotective activities. To evaluate the effects of PSP on septic liver injury and demonstrate the potential molecular mechanisms, the septic acute liver injury (SALI) model was established in BALB/c mice via intraperitoneal injection of lipopolysaccharide (LPS). We found that PSP treatment could remarkably reduce the 48 h mortality rate of septic mice; alleviate liver histopathologic damage; lower the activity of neutrophil infiltration marker MPO in liver tissue; and decrease the levels of liver function indexes AST, ALT, ALP, and TBIL, inflammatory cytokines TNFα and IL-6, and pyroptosis-related inflammatory cytokines IL-18 and IL-1ß in serum. TUNEL staining and detecting GSDMD-NT protein expression level in liver tissue revealed that PSP could restrain excessive pyroptosis. In addition, PSP treatment reversed the upregulations of mRNA expression levels of the NLRP3/GSDMD signals in the liver. Our results indicated the potential protective role of PSP against SALI by inhibiting pyroptosis via NLRP3/GSDMD signals.

Klebsiella pneumonia and Its Antibiotic Resistance: A Bibliometric Analysis.

The rapid development of antibiotic resistance in K. pneumonia has led to a major concern. In order to analyze the hotspots and develop trends in this field through visual the analysis, this study used CiteSpace software to summarize the available data in the literature to provide insights. A total of 9366 research articles were retrieved from the Web of Science Core Collection, and the number of published papers is increasing year by year. The country with the most articles was the USA, followed by China and India. The institution with the highest number of publications was LERU. The author with the highest number of articles was Li. The journal with the highest citation rate was Antimicrobial Agents and Chemotherapy. In addition, based on keyword coword analysis and cited literature prominence analysis by CiteSpace, the current research focus in the field was therapy, CRKP, and resistance genes. This paper provides a new quantitative visualization way for the development of the field in the recent ten years. The results show global trends that researchers can use to determine future directions.

Study on Synergistic Antioxidant Effect of Typical Functional Components of Hydroethanolic Leaf Extract from Ginkgo Biloba In Vitro.

The predicted anti-oxidation is related to apoptosis, proliferation, lipid metabolism, cell differentiation, and immune response. There are some differences in the antioxidant capacity of the four typical components of ginkgo biloba extract (EGb) including ginkgo flavone (GF), ginkgolide (G), procyanidins (OPC), and organic acids (OA), and any two members of them can exhibit apparent synergistic effects. The order of DPPH scavenging ability was: OPC > GF > OA > G. The scavenging ability of procyanidins was close to that of VC; the scavenging capacity of ABTS was GF > OPC > OA > G. The GF:OPC (1:9) showed the best synergism in scavenging DPPH and ABTS radicals. The 193 kinds of small molecules reported in EGb were obtained by analyzing the properties of EGb. In order to construct a corresponding biological activity target set, molecular docking and the network pharmacology method were employed to build the molecular action mechanism network of a compound target, and the main biological functions and signaling pathways involved with their antioxidant activities were predicted. The results displayed that the top ten compounds which belonged to the two broad categories, ginkgo flavonoids and proanthocyanidins, could interact closely with several important target proteins (CASP3, SOD2, MAPK1, HSPA4, and NQO1). This would be expected to lay a theoretical foundation for the deep development of Ginkgo biloba extract.

Optimizing the Desorption Technology of Total Flavonoids of Ginkgo Biloba from Separating Materials of Activated Carbon.

Activated carbon adsorption is one of the processes used to produce ginkgolides from the extract of Ginkgo biloba (EGB) in most enterprises. However, the problem is that the ginkgolides can be eluted by ethanol after the Ginkgo biloba extracts are adsorbed by activated carbon, while total ginkgo flavonoids (TGFs) would form dead adsorption, leading to the ineffective utilization of TGFs. In this paper, the maximum adsorption capacity of TGFs by activated carbon was 226.7 mg/g activated carbon at pH 5, and the adsorption of TGFs was easier and more favorable to monolayer adsorption. On this basis, the technical process of desorption of TGFs from activated carbon preparation technology was optimized by using the response surface optimization technique. Under the optimum process (the elution volume was 116.75 mL, the ethanol concentration in the eluent was 73.4%, the elution temperature was 31.5 °C, and the ammonia concentration was 5.7%), the desorption rate of TGFs was 74.56%. Scanning electron microscopy morphological analysis showed that the used activated carbon had a wide pore size distribution, with the micropore pore size mainly concentrated around 0.64 and 1.00 nm and the mesopore pore size mainly concentrated between 2.89 and 39.5 nm. In addition, the molecular weight of ginkgo flavonoids is mainly distributed between 500 and 1000 Da, which can be transported to the micropores through the mesopore channels. On the other hand, there is a force between the flavonoids and the acidic oxygen-containing functional groups on the pore surface, which is the main reason for the formation of dead adsorption. The obtained results contribute to further improving the process of adsorbing and desorbing TGFs from EGB and lay a foundation for the development of more suitable activated carbon.

Echinacoside ameliorates alcohol-induced oxidative stress and hepatic steatosis by affecting SREBP1c/FASN pathway via PPARα.

Alcoholic liver disease (ALD) is one of the most common health problems for drinkers, especially in men. Echinacoside (ECH), a natural phenylethanoid glycoside welcomed by the market, has been shown to have a variety of biological activities, such as neuroprotective, anti-fatigue, anti-diabetes and so on. Here, the protective effect and the underlying mechanism of ECH on ethanol-induced liver injuries were studied. In vitro, the HepG2 cells were treated with ECH prior to ethanol. In vivo, C57BL/6 J mice were fed a Lieber-DeCarli ethanol liquid diet and gave with or without 100 mg/kg ECH for 10 days. Our experiments showed that ECH significantly enhanced the levels of antioxidants and reduced the level of ROS, thus attenuating ethanol-induced oxidative stress. Besides, ECH attenuated lipid accumulation caused by ethanol, as evidenced by oil-red O staining, histological examination and the quantification of TG and TC. Finally, ECH increased the level of PPAR-α, and reduced the levels of SREBP-1c and FASN. When PPAR-α inhibitor was introduced in the system, the effects of ECH on SREBP-1c and FASN were reversed. Taken together, our study suggest that ECH can protect against ethanol-induced liver injuries via alleviating oxidative stress and hepatic steatosis by affecting SREBP-1c/FASN pathway via PPAR-α.

Molecular dynamics simulation of CO2-switchable surfactant regulated reversible emulsification/demulsification processes of a dodecane-saline system.

CO2-Switchable surfactants are of great potential in a wide range of industrial applications related to their ability to stabilize and destabilize emulsions upon command. Molecular dynamics simulations have been performed to reveal the fundamental mechanism of the reversible emulsification/demulsification processes of a dodecane-saline system by a CO2-switchable surfactant that switches between active (i.e., N'-dodecyl-N,N-dimethylacetamidinium (DMAAH+)) and inactive (i.e., N'-dodecyl-N,N-dimethylacetamidine (DMAA)) forms. The density profiles indicate that DMAAH+ could increase the oil-water interfacial thickness to a greater extent compared to DMAA. DMAAH+ could sharply reduce the interfacial tension of the dodecane-saline system, while DMAA only exhibits a limited decrease, which is in accordance with the experimental observation that DMAAH+/DMAA can reversibly emulsify/demulsify alkane-water systems. Our simulations showed that both the number and lifetime of hydrogen bonds (HBs) between DMAA and water are almost equal to those between DMAAH+ and water. In DMAA, the N atom connecting with the alkyl tail acted as a HB acceptor, while the N atom attached by a proton in DMAAH+ acted as a HB donor. Furthermore, the HBs between DMAAH+ and HCO3- at the interfaces are relatively limited. Hence, it is deduced that the HBs are insufficient to achieve the CO2-switchability of DMAA/DMAAH+. The Lennard Jones and coulombic potentials between DMAA/DMAAH+ and other species show that the coulombic potentials between DMAAH+ and water or anions (i.e., Cl- and HCO3-) sharply decrease with the increase of DMAAH+ and are much lower than those in models with DMAA. The enhanced coulombic interactions between DMAAH+ and anions lead to a remarkable reduction in interfacial tension and the emulsification of the alkane-saline system. Therefore, coulombic interactions are of crucial importance to the reversible emulsification/demulsification processes regulated by CO2-switchable surfactants, namely DMAAH+/DMAA.

Enhancing UDP-Rhamnose Supply for Rhamnosylation of Flavonoids in Escherichia coli by Regulating the Modular Pathway and Improving NADPH Availability.

UDP-rhamnose is the main type of sugar donor and endows flavonoids with special activity, selectivity, and pharmacological properties by glycosylation. In this study, several UDP-glucose synthesis pathways and UDP-rhamnose synthases were screened to develop an efficient UDP-rhamnose biosynthesis pathway in Escherichia coli. Maximal UDP-rhamnose production reached 82.2 mg/L in the recombinant strain by introducing the cellobiose phosphorolysis pathway and Arabidopsis thaliana UDP-rhamnose synthase (AtRHM). Quercitrin production of 3522 mg/L was achieved in the recombinant strain by coupling the UDP-rhamnose generation system with A. thaliana rhamnosyltransferase (AtUGT78D1) to recycle UDP-rhamnose. To further increase UDP-rhamnose supply, an NADPH-independent fusion enzyme was constructed, the UTP supply was improved, and NADPH regenerators were overexpressed in vivo. Finally, by optimizing the bioconversion conditions, the highest quercitrin production reached 7627 mg/L with the average productivity of 141 mg/(L h), which is the highest yield of quercitrin and efficiency of UDP-rhamnose supply reported to date in E. coli. Therefore, the method described herein for the regeneration of UDP-rhamnose from cellobiose may be widely used for the rhamnosylation of flavonoids and other bioactive substances.

Deoxyelephantopin decreases the release of inflammatory cytokines in macrophage associated with attenuation of aerobic glycolysis via modulation of PKM2.

Growing evidence suggests that activated immune cells undergo metabolic reprogramming in the regulation of the innate inflammatory response. Remarkably, macrophages activated by lipopolysaccharide (LPS) induce a switch from oxidative phosphorylation to aerobic glycolysis, and consequently results in release of proinflammatory cytokines. Pyruvate Kinase M2 (PKM2) plays a vital role in the process of macrophage activation, promoting the inflammatory response in sepsis and septic shock. Deoxyelephantopin (DET), a naturally occurring sesquiterpene lactone from Elephantopus scaber, has been shown to counteracts inflammation during fulminant hepatitis progression, but the underlying mechanism remains unclear. Here, we studied the function of the DET on macrophage activation and investigated the anti-inflammatory effects of DET associated with interfering with glycolysis in macrophage. Our results first demonstrated that DET attenuates LPS-induced interleukin-1ß (IL-1ß) and high-mobility group box 1 (HMGB1) release in vitro and in vivo and protected mice against lethal endotoxemia. Furthermore, DET decreased the expression of pyruvate dehydrogenase kinase 1 (PDK1), glucose transporter 1(GLUT1), lactate dehydrogenase A (LDHA), and reduced lactate production dose-dependently in macrophages. Moreover, we further revealed that DET attenuates aerobic glycolysis in macrophages associated with regulating the nuclear localization of PKM2. Our results provided a novel mechanism for DET suppression of macrophages activation implicated in anti-inflammatory therapy.

Distribution and Mobility of Crude Oil-Brine in Clay Mesopores: Insights from Molecular Dynamics Simulations.

The value of crude oil accommodated in shale has been recognized and has attracted increasing attention from the academic and industrial society. The occurrence and mobility of crude oil in clay pores, therefore, become essential issues for evaluation and recovery of shale oil. The distribution, structure, and transport of the oil-brine mixture confined in a slit-shaped montmorillonite mesopore with different water amounts have been investigated using equilibrium molecular dynamics and nonequilibrium molecular dynamics (NEMD) simulations. A mimic model of crude oil, a mixture of 19 organic molecules, was employed, and thus the behavior of different organic molecules could be characterized in detail. A temperature of 410 K and a pressure of 300 atm corresponding to a buried depth of 3 km were employed. The simulations indicate that the water amount determines the distribution of crude oil. Water and metal ions prefer to cover on hydrophilic montmorillonite surfaces, while nonpolar hydrocarbons tend to be far away from clay surfaces. As the water amount is too low to completely cover the clay surfaces, some polar organic molecules will come into contact with the uncovered clay surface. Abundant organic acid molecules adsorb onto montmorillonite surfaces mainly through participating in the inner-sphere complexes of Na+ ions closely located at montmorillonite surfaces (i.e., Na+ cation bridge) and forming hydrogen bonds with water molecules in the vicinity. Carbazole molecules tend to aggregate together due to π-π stacking, while thioether molecules mix within alkane molecules and exhibit no characteristic distributions. The mobility of all oil components decreases with the decrease of the water amount, and the mobility of polar components (i.e., organic acid and carbazole) is relatively lower than that of nonpolar hydrocarbons. NEMD simulations clearly indicate that the transport velocity of crude oil markedly increases with the water amount under a specific pressure gradient. The brine covering on clay surfaces significantly weakens oil-clay interfacial interactions. Polar components, especially organic acid, exhibit relatively low transport velocity compared with nonpolar hydrocarbons. These findings highlight the understanding of physical-chemical behaviors of shale oil and provide atomistic information for technology development for enhancing oil recovery.

Quercetin Inhibits the Proliferation of Glycolysis-Addicted HCC Cells by Reducing Hexokinase 2 and Akt-mTOR Pathway.

Increased glycolysis in tumor cells is associated with increased risk of tumor progression and mortality. Therefore, disruption of glycolysis, one of the main sources of cellular energy supply, can serve as a target for suppressing tumor growth and progression. Of note, hexokinase-2 (HK2) plays vital roles in glucose metabolism. Moreover, the expression of HK2 alters the metabolic phenotype and supports the continuous growth of tumor cells, making it an attractive target for cancer therapy. Quercetin (QUE), a bioactive flavonoid, has a profound anti-tumor effect on hepatocellular carcinoma (HCC), but the precise underlying mechanism of this effect is unclear. In the present study, we reported that QUE inhibited the proliferation of HCC cells that relied on aerobic glycolysis. We further found that QUE could decrease the protein levels of HK2 and suppress the AKT/mTOR pathway in HCC cells. In addition, QUE significantly restrained the growth of HCC xenografts and decreased HK-2 expression in vivo. Taken together, we have revealed that QUE suppresses the progression of HCC by inhibiting HK2-dependentglycolysis, which may have a promising potential to be an effective treatments for HCC, especially for those patients with high HK2 expression.

Enrichment and Purification of Total Ginkgo Flavonoid O-Glycosides from Ginkgo Biloba Extract with Macroporous Resin and Evaluation of Anti-Inflammation Activities In Vitro.

In the present study, the performance and separation characteristics of six macroporous resins for the enrichment and purification of total ginkgo flavonoid O-glycosides (TGFs) (quercetin (I), kaempferol (II), isorhamnetin (III)) from Ginkgo Biloba extracts (EGB) are evaluated. The adsorption and desorption properties of TGFs are studied on macroporous resins, including D101, D201, AB-8, HPD400, D301, and D311. Along with the results, AB-8 resin exhibits the best adsorption and desorption capacity for these three ginkgo flavonoid O-glycosides among the six resins. Adsorption isotherms are created on AB-8 resin and fit well to the Langmuir (R² > 0.96) and Freundlich (R² > 0.92, 0.3 < 1/n < 0.7) models. After the treatment with gradient elution on AB-8 resin packed chromatography column, the contents of the three main ginkgo flavonoid O-glycosides (I, II, and III) increase from 8.93%, 9.88%, and 6.11% in the extracts to 30.12%, 35.21%, and 14.14%, respectively, in the product. The recoveries of compounds I, II, and III are 88.76%, 93.78%, and 60.90%, respectively. Additionally, the anti-inflammatory effects of TGFs are evaluated in LPS-treated RAW 264.7 macrophages, and the result demonstrates that TGFs could significantly inhibit LPS-induced NO release in vitro in a dose-dependent manner compared with the control group. These findings suggest that TGFs could potentially be natural antioxidants and anti-inflammatory ingredients that could be used in pharmaceutical products and functional food additives.

Identification of Human Acetylcholinesterase Inhibitors from the Constituents of EGb761 by Modeling Docking and Molecular Dynamics Simulations.

AIM AND OBJECTIVE: EGb761, a standardized and well-defined product extract of Ginkgo biloba leaves, has beneficial role in the treatment of multiple diseases, particularly Alzheimer's disease (AD). Identification of natural acetylcholinesterase (AChE) inhibitors from EGb761 would provide a novel therapeutic approach against the Alzheimer's disease. MATERIAL AND METHOD: A series of 21 kinds of promising EGb761 compounds were selected, and subsequently evaluated for their potential ability to bind AChE enzyme by molecular docking and a deep analysis of protein surface pocket features. RESULTS: Docking results indicated that these compounds can bind tightly with the active site of human AChE, with favorable distinct interactions around several important residues Asp74, Leu289, Phe295, Ser293, Tyr341, Trp286 and Val294 in the active pocket. Most EGB761 compounds could form the hydrogen bond interactions with the negatively charged Asp74 and Phe295 residues. Among these compounds, diosmetin is the one with the best-predicted docking score while three key hydrogen bonds can be formed between small molecule and corresponding residues of the binding site. Besides, other three compounds luteolin, apigenin, and isorhamnetin have better predicted docking scores towards AChE than other serine proteases, i.e. Elastase, Tryptase, Factor XA, exhibiting specificity for AChE inhibition. The RMSD and MM-GBSA results from molecular dymamic simulations indicated that the docking pose of diosmetin-AChE complex displayed highly stable, which can be used for validating the accuracy of molecular docking study. Subsequently, the AChE inhibitory activities of these compounds were evaluated by the Ellman's colorimetric method. CONCLUSION: The obtained results revealed that all the four compounds exhibited modest AChE inhibitory activity, among which Diosmetin manifested remarkable anti-AChE activity, comparable with the reference compound, Physostigmine. It can be deduced that these EGB761 compounds can be regarded as a promising starting point for developing AChE inhibitors against AD.

Hydration of methane intercalated in Na-smectites with distinct layer charge: insights from molecular simulations.

Molecular dynamic simulations have been carried out to investigate the behavior of methane hydration in Na-smectite interlayers with different layer-charge distributions and water contents under certain pressure-temperature (P-T) conditions, which is analogous to the methane hydrate-bearing marine sediments. It was found that sufficient interlayer water is necessary for coordinating with methane and forming hydrate-like structures. Methane molecules are solvated by nearly 12-13 water molecules and coordinated with six oxygen atoms from the clay surface in the interlayer of nontronite as well as in montmorillonite. The mobility of the interlayer water of smectite, which is determined by the layer-charge amount and distribution of smectite, also influences the stability of hydrate methane complexes. The tetrahedral negative charge site is closer to the surface than the octahedral charge site and is more effective in confining water than methane water molecules.

[Isolation and characteristic of SmbHLH1 gene in Salvia miltiorrhiza].

OBJECTIVE: A novel bHLH-like gene, designated SmbHLH1, was isolated from Salvia miltiorrhiza, in order to identify a bHLH gene in related to danshinone biosysnthesis. METHOD: SmbHLH1 was isolated by RT-PCR,and Semi-quantitative RT-PCR was used to detect the gene expression level. RESULT: The full length of SmbHLH1 cDNA has an open reading frame of 999 bp. The deduced amino acid sequence of SmbHLH1 has 332 amino acid residues which forms a 36 kDa polypeptide with a calculated pI of 5.4. SmbHLH1 gene was expressed at high level in root, but low level in stem, leaf and flower of S. miltiorrhiza. The transcripts of SmbHLH1 was suppressed when the plants were treated with exogenous MeJA, Yeast + Ag+. The transcripts of SmbHLH1 constitutively accumulated in response to exogenous ABA and low concentration of salicylic acid. CONCLUSION: SmbHLH is a new member of the S. miltiorrhiza bHLH family, and its possible roles in brassinosteriods signaling responses.