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The interaction of bovine serum albumin (BSA) with Ginsenoside Rd (GSRd) was studied using multiple spectroscopic methods, isothermal titration calorimetry (ITC), molecular docking and density func...

In this paper, a kind of soybean nodule-derived nitrogen-doped carbon (SNNDC) was prepared, characterized and applied to modify the assembled carbon paste electrode (CPE), to fabricate a novel chemical sensor for the detections of AA and DA. The electrochemical characteristics of SNNDC implied that it is an effective electron transfer mediator accelerating the electron transfer to CPE. The cyclic voltammetry measurements at different scan rates indicated that the electrochemical process on the electrode surface of the chemical sensor is a diffusion-controlled irreversible oxidation reaction of one-electron and one-proton for DA, and two-electron with one-proton for AA. The linear detection ranges of the chemical sensor for the detections of AA and DA were 5–3000 μM and 5–1000 μM with the detection limits of 1.90 μM and 3.18 μM, respectively, as determined by amperometric experiments. Both linear detection range and detection limit obtained are comparable or better than those of several modified electrodes reported recently. And the chemical sensor was also successfully applied to the detections of AA and DA in injection samples. This study suggested that the fabricated chemical sensor is a hopeful candidate to be used in the detection of pharmaceutical samples of AA and DA, and provides valuable reference information for the development of novel drug sensors in both clinical laboratory and food industries.

The interaction mechanism of a kind of natural drug helicid with typical digestive enzyme trypsin was investigated using multi-spectroscopic techniques and molecular modeling method. The fluorescen...

European eel (Anguilla anguilla) is considered to be a vital commercial fish species. In this study, the effect and molecular mechanism of bioactive peptides from European eel on macrophage-stimulating activity in RAW264.7 cells were investigated. Eel peptide (EP) markedly induced NO and iNOS production and promoted TNF-α and IL-6 secretion in a concentration-dependent manner. Moreover, EP dose-dependently activated NF-κB and MAPK signaling pathways in RAW264.7 cells. In addition, EP was purified using a Sephadex A-25 column and a Bio-Gel P-6 column, and the fraction (Fr-1-1) showing the strongest NO-inducing activity was obtained. Then, the molecular weights of the components in Fr-1-1 were analyzed by LC-MS/MS and found to range from 700 to 1900 Da for the majority of components, which suggested that Fr-1-1 mainly consisted of peptides containing 8-20 amino acid residues. Overall, our results indicated that EP from Anguilla anguilla activated macrophages and could be used as a potential nutraceutical or pharmaceutical.

Alginate is an unbranched polymer composed of polymannuronate (PM) and polyguluronate and widely used as a colloid in food industries. Seleno-polymannuronate (Se-PM), a kind of seleno-polysaccharide, was synthesized through selenylation replacement reaction of PM. And its neuroimmunoregulatory activity in LPS-induced BV2 cells and in vivo septic shock model was conducted. Se-PM could significantly attenuate the NO and PGE2 secretion, as well as the iNOS and COX-2 expression, and the release of TNF-α and IL-1β, 6 and 12 in LPS-activated microglia. Meanwhile, the changes in cellular morphology and migration were recovered by pretreating the LPS-activated microglia with Se-PM. Moreover, the overactivation of the NF-κB and MAPK signaling pathways stimulated by LPS in BV2 microglia was prominently alleviated by Se-PM. In the septic shock mouse model, Se-PM could remarkably decrease the TNF-α and IL-6 production in the serum and brain. These results indicate that alginate-derived Se-PM is a good candidate to be used in alternative/supplementary medication or functional foods for treating/managing neurodegenerative disorder.

Sediment samples in this study were taken from five typical sites near the outlet of Shekou industrial district of Shenzhen City, China. The concentrations of seven elements including Cr, Cu, Cd, Pb, Hg, Zn, and As were determined respectively by atomic absorption spectrometry or atomic fluorescence spectrometry. The pollution degrees of the seven elements were assessed with the contamination factor and potential ecological risk index respectively, and their different sources were identified using multivariate statistical methods. The calculated contamination factors of these elements indicated that the sediments were at least moderately polluted by all the surveyed elements except As. The values of potential ecological risk indexes obtained decreased as the following order: Cd > Hg > Cu > As > Pb > Zn > Cr, and suggested that Cd and Hg were respectively at high and considerable environmental health risks. In addition, multivariate statistical analyses indicated that Cd, Hg, Cu, and Zn were most likely from the waste of electroplating, metal, and battery industries at Shekou industrial district, while Pb and As originated from both natural processes and anthropogenic activities along the bank of Pear River such as coal transportation and combustion, glass manufacturing, and painting, and Cr came mostly from Cr-related industries especially leather tanning within Shenzhen City. This study provided useful reference information about heavy metal contamination in the sediments in the estuarine and coastal areas with rapid urbanization and industrialization, and should be very helpful for the local governments to make relevant policies and strategies of heavy metal contamination control and management in developing countries.

Sediment samples in this study were taken from five typical sites near the outlet of Shekou industrial district of Shenzhen City, China. The concentrations of seven elements including Cr, Cu, Cd, Pb, Hg, Zn, and As were determined respectively by atomic absorption spectrometry or atomic fluorescence spectrometry. The pollution degrees of the seven elements were assessed with the contamination factor and potential ecological risk index respectively, and their different sources were identified using multivariate statistical methods. The calculated contamination factors of these elements indicated that the sediments were at least moderately polluted by all the surveyed elements except As. The values of potential ecological risk indexes obtained decreased as the following order: CdHgCuAsPbZnCr, and suggested that Cd and Hg were respectively at high and considerable environmental health risks. In addition, multivariate statistical analyses indicated that Cd, Hg, Cu, and Zn were most likely from the waste of electroplating, metal, and battery industries at Shekou industrial district, while Pb and As originated from both natural processes and anthropogenic activities along the bank of Pear River such as coal transportation and combustion, glass manufacturing, and painting, and Cr came mostly from Cr-related industries especially leather tanning within Shenzhen City. This study provided useful reference information about heavy metal contamination in the sediments in the estuarine and coastal areas with rapid urbanization and industrialization, and should be very helpful for the local governments to make relevant policies and strategies of heavy metal contamination control and management in developing countries.

The interaction of lipase with Ligupurpuroside B was studied by multiple spectroscopic techniques, enzyme activity and molecular modeling under simulative physiological condition. According to Stern-Volmer equation, fluorescence of lipase was quenched by Ligupurpuroside B via a static quenching mechanism because of formation of Ligupurpuroside B-lipase complex. Binding constants, number of binding sites & thermodynamic parameters were evaluated. The values of ΔGo (−25.085 kJ mol−1), ΔHo (−12.14 kJ mol−1) and ΔSo (+43.45 J mol−1 K−1) at 298 K indicated that Ligupurpuroside B-lipase interaction is spontaneous and hydrophobic interaction is the main force stabilizing the Ligupurpuroside B-lipase complex. The enzyme activity assay showed that Ligupurpuroside B inhibited lipase activity efficiently. Synchronous fluorescence spectra (SFS) suggested that Ligupurpuroside B is closer to Trp residues than to Tyr residues. All above experimental results were confirmed by molecular docking studies, which further indicated the binding site of Ligupurpuroside B on the surface of lipase, and the amino acid residues of lipase interacting with Ligupurpuroside B. Our present research work gives valuable information on the design of drugs with lipase as a carrier and should be useful for food industries.

Polymannuronate (PM) is an acidic polymer separated from alginate. PM is a linear block polysaccharide in edible brown algae that has been widely used in the food industry. Seleno-polymannuronate (Se-PM) is a seleno-derivative of PM synthesized from PM and Na2SO3 in our laboratory. We investigated the anti-neuroinflammatory activity of Se-PM in lipopolysaccharide (LPS)-activated primary microglia and astrocytes and a mouse model of acute inflammation. Our results show that Se-PM could markedly reduce NO and PGE2 production, iNOS and COX-2 expression, and TNF-α, IL-1β and IL-6 secretion in LPS-treated primary microglia and astrocytes. Moreover, the LPS-triggered overactivation of NF-κB and MAPK signalling was attenuated by Se-PM. In addition, in vivo, LPS-induced microglial and astrocytic activation was remarkably suppressed by Se-PM. These results suggest that Se-PM merits exploration as an alternative medicinal or functional food for alleviating neuroinflammation.

Enzyme-activity essay demonstrated that Ligupurpuroside A acts as a natural inhibitor of lipase in a competitive manner. The inhibition mechanism and nature of lipase by Ligupurpuroside A were investigated by fluorescence spectra, UV–Vis absorption spectra, circular dichroism (CD) spectra and molecular docking methods. Fluorescence experiments indicated that Ligupurpuroside A can quench the intrinsic fluorescence of lipase through a static quenching procedure. Thermodynamic analysis suggested that hydrophobic interaction is the main force between lipase and Ligupurpuroside A. Fluorescence resonance energy transfer experiment showed that an energy transfer from lipase to Ligupurpuroside A occurs with great possibility, confirming the presence of static quenching mechanism of lipase fluorescence by Ligupurpuroside A. Interestingly, conformation of lipase remained almost the same after bound to Ligupurpuroside A based on CD spectral experiments. All these experimental results were validated by the protein-ligand docking studies which further showed that Ligupurpuroside A could bind to the amino acid residues of the hydrophobic cavity on catalytic sites of lipase. This study should be helpful for the design of diet drug and the full use of Ligupurpuroside A in food industry.

Abstarct The electrosensing of chlorzoxazone (CHZ) was studied for the first time at nanostructured Au/graphene modified glassy carbon electrode (AuNPs/Gr/GCE) employing different voltammetric techniques viz. cyclic, linear sweep and differential pulse voltammetries. The results indicated that the voltammetric response of CHZ was improved distinctly at the AuNPs/Gr/GCE electrode than that at bare GCE. In order to carry out the CHZ determination, the dependency of the response current on supporting electrolyte pH, sweep rate and CHZ concentration were inspected to optimize the investigational conditions. The surface characterizations of the Au/graphene modified and unmodified glassy carbon electrodes were carried out. The anodic peak showed a process of diffusion-control. The number of electrons transferred was calculated to be two. The determination of [CHZ] using the modified electrode was studied over the range of 1.0 × 10−7 M to 10.0 × 10−7 M which showed the LOD value to be 1.164 × 10−8 M. The study of excipients showed that the method owns selectivity. A differential pulse voltammetry which is fast and simple, showed a good accuracy and precision, for the purpose of determining the [CHZ] in biomedical applications like pharmaceutical formulation and also in pathological sample testing. In addition, this type of work can find its usage towards scientific purposes that involves electrical measurements, particularly in industrial quality management, environmental pollution management, as it involves simple sample preparation, appreciable repeatability, reproducibility and also high sensitivity.

Alginate is a naturally acidic polysaccharide consisting alternately of β-d-mannuronic acid and α-l-guluronic acid with 1, 4-glycosidic linkages and is derived from brown seaweeds. Herein, the effect of alginate on the promotion of macrophage phagocytosis and the corresponding molecular mechanisms were investigated in murine RAW264.7 cells. Alginate could enhance the intracellular phagocytosis of gold nanoparticles (AuNPs), fluorescent microspheres and immunoglobulin G (IgG)-opsonized Staphylococcus aureus (S. aureus). Moreover, alginate increased Toll-like receptor 4 (TLR4) expression and activated the Akt/nuclear factor-κB (NF-κB) and p38 mitogen-activated protein kinase (MAPK) signalling pathways. Alginate-promoted phagocytosis was suppressed by the addition of inhibitors of TLR4, NF-κB and p38 MAPK and by TLR4 gene knockdown, indicating the involvement of these key components. This work is the first to propose that alginate promotes phagocytosis via upregulating TLR4 expression and stimulating the Akt/NF-κB and p38 MAPK signalling pathways, which may contribute to the capacity of alginate to activate macrophages.

The sediment samples were collected from eight sites located in the Pearl River Estuary and the Shenzhen Bay of the west coast of Shenzhen. The distributions of the seven elements Zn, Cr, Hg, Cu, Cd, Pb and As have been analyzed, and their pollution degrees, corresponding potential ecological risks and source identifications have been studied using geo-accumulation index, potential ecological risk index and integrated multivariate statistical methods, respectively. Based on the calculated geo-accumulation indices, the contamination levels of all elements in the Pearl River Estuary are similar to those in the Shenzhen Bay, reflecting that these elements in the study areas have similar sources because of the adequate seawater exchange. The calculated potential ecological risk indices suggest that Cd and Hg are at considerable and moderate risk, respectively. Multivariate statistical analyses further reveal that Zn, Hg, Cd and Pb originated from industrial wastewater, while Cr and Cu are mainly from both industrial wastewater and agricultural sources, and As is mainly from natural source. These research results provide baseline information for both the coastal environment management and the worldwide heavy metal distribution and assessment.

Ligupurpuroside A is a glycoside extracted from Ku-Ding tea. As extracts from Ku-Ding tea exhibit anti-inflammatory property, we hypothesize that Ligupurpuroside A may be an active compound which inhibits trypsin activity during the anti-inflammatory process. The mechanism and nature of inhibition of trypsin by Ligupurpuroside A have been studied by multi-spectroscopic method, enzyme-activity assay and molecular docking. Enzyme activity assay reveals that Ligupurpuroside A significantly inhibits the activity of trypsin through a competitive manner with an IC50 value of 3.08 × 10−3 mol L−1. Fluorescence titration together with thermodynamic analysis indicate that a Ligupurpuroside A-trypsin complex is formed, and that hydrophobic force and hydrogen bonding are the main forces stabilizing the complex. UV-vis absorption, synchronous fluorescence and circular dichroism spectra show that the interaction between Ligupurpuroside A and trypsin induces conformational changes of trypsin with a decrease in the contents of α-helix and β-sheet. Finally, molecular docking further suggests that Ligupurpuroside A molecule binds within the active pocket of trypsin via hydrophobic force and hydrogen bond. Results from this study of the interaction of trypsin with its natural inhibitor should be useful to minimize the antinutritional effects and make full use of tea extracts in the food industry, and be also helpful to the design of the drugs for the diseases related to overexpression of trypsin.

The objective of this longitudinal study was to identify growth curves and related predictors of depressive symptoms among Chinese adolescent earthquake survivors. A total of 1573 adolescent survivors of the 8-magnitude Wenchuan earthquake were assessed through the Depression Self-Rating Scale for Children (cutoff for probable clinical depression: 15), Social Support Rate Scale, Adolescent Self-Rating Life Events Checklist, and a self-designed questionnaire covering earthquake exposure and demographic information at 6-, 12-, 18-, 24- and 30-months after the earthquake. Data were analyzed using growth mixture modeling (GMM) and multinomial logistic regression. The prevalence rates of depressive symptoms were 27.6%, 40.6%, 30.9%, 37.5% and 29.8% at 6-, 12-, 18-, 24- and 30-months, respectively. GMM analysis showed four patterns of growth curves for depressive symptoms: chronic depression (25.6% of the sample), recovery (1.7%), delayed depression (4.3%), and resilience (68.4%). Female gender was related with decreased probability of resilience. Direct witness of tragic scenes during the earthquake was related with higher risk for chronic depression. More negative life events and fewer social support were also common predictors of not developing the resilience pattern. The need of providing appropriate individualized interventions for high-risk adolescent earthquake survivors is indicated., Highlights • About 2/3 of adolescent survivors showed persistent euthymia post-earthquake. • About one quarter of them showed persistent depressive symptomatology. • Others showed a gradual relief or delayed-onset of depressive symptoms over time. • Female sex and directly viewing tragic scenes lowered the probability for euthymia. • Life adversity and less social support also predicted worse outcome than euthymia.

Study on the binding properties of helicid by pepsin systematically using multi-spectroscopic techniques and molecular docking method, and these interactions comprise biological recognition at molecular level and backbone of biological significance in medicine concerned with the uses, effects, and modes of action of drugs. We investigated the mechanism of interaction between helicid and pepsin by using various spectroscopic techniques viz., fluorescence spectra, UV–Vis absorption spectra, circular dichroism (CD), 3D spectra, synchronous fluorescence spectra and molecular docking methods. The quenching mechanism associated with the helicid–pepsin interaction was determined by performing fluorescence measurements at different temperatures. From the experimental results show that helicid quenched the fluorescence intensity of pepsin via a combination of static and dynamic quenching process. The binding constants (Ka) at three temperatures (288, 298, and 308 K) were 7.940 × 107, 2.082 × 105 and 3.199 × 105 L mol−1, respectively, and the number of binding sites (n) were 1.44, 1.14, and 1.18, respectively. The n value is close to unity, which means that there is only one independent class of binding site on pepsin for helicid. Thermodynamic parameters at 298 K were calculated as follows: ΔHo (− 83.85 kJ mol−1), ΔGo (− 33.279 kJ mol−1), and ΔSo (− 169.72 J K−1 mol−1). Based on thermodynamic analysis, the interaction of helicid with pepsin is driven by enthalpy, and Van der Waals’ forces and hydrogen bonds are the main forces between helicid and pepsin. A molecular docking study further confirmed the binding mode obtained by the experimental studies. The conformational changes in the structure of pepsin was confirmed by 3D fluorescence spectra and circular dichroism.

Alginate-derived polymannuronate (PM) is a type of polysaccharide found in edible brown seaweeds. Seleno-polymannuronate (Se-PM) was prepared from PM via synthesis using sulfation- and selenation-replacement reactions. The anti-inflammatory activity of Se-PM and its corresponding molecular mechanisms were investigated. In lipopolysaccharide (LPS)-activated murine macrophage RAW264.7 cells, Se-PM significantly attenuated the production of nitric oxide (NO), prostaglandin E2 (PGE2), and reactive oxygen species (ROS); the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2); and the secretion of proinflammatory cytokines. Moreover, Se-PM remarkably suppressed the LPS-induced activation of the nuclear-factor (NF)-κB and mitogen-activated-protein-kinase (MAPK) signaling pathways in RAW264.7 cells. Furthermore, Se-PM also decreased the production of proinflammatory mediators in LPS-triggered primary murine macrophages. Additionally, Se-PM inhibited the inflammatory response in the a...

A pair of ruthenium(II) complex enantiomers, Δ- and Λ-[Ru(bpy)2PBIP]2+ {bpy=2,2'-bipyridine, PBIP=2-(4-bromophenyl)imidazo[4,5-f]1,10-phenanthroline} have been synthesized and characterized. The systematic comparative studies between two enantiomers on their DNA binding-behaviors with calf thymus DNA (CT DNA) were carried out by viscosity measurements, spectrophotometric methods and molecular simulation technology. Additional assays were performed to explore the cytotoxicity of the ruthenium(II) enantiomers against tumor cell lines. DNA-binding studies show that both the enantiomers can bind to CT DNA via intercalative mode, and the Δ form binds to CT DNA more strongly than the Λ form does. Molecular simulation further shows that both the two enantiomers intercalate between base pairs of DNA in minor groove, and that the Δ form intercalates into DNA more deeply than the Λ form does. In addition, the cell proliferation assays show that the Δ form induces a greater cytotoxicity than the Λ form on human cervical cancer HeLa cells, which is positive correlated with the results in DNA binding studies and molecular docking, and implies that the DNA binding affinities of ruthenium(II) polypyridyl complexes might be constitute to the part of their anticancer mechanisms.

A population model discriminating the hyphae according to the hyphal length and a morphologically structured model considering the specific function of different morphological forms of a hypha are combined together to describe mycelial growth, substrate consumption and secondary metabolite formation in streptomycin fermentation. In the population model, the growth modes of hyphae with different age or length are considered, while in the morphologically structured model, the morphological forms of hyphae and their functions in growth and metabolism are described. The population model and the morphologically structured model are interrelated by a branching function and a differentiation function. In the model, the growth rate of immature apical compartment is distinguished from those of matured ones, branching is proposed to occur only in the subapical region, and the hyphal compartment is assumed to synthesize secondary metabolites. The model is successfully applied to simulate the batch fermentation process of streptomycin production. The growth characteristics of filamentous microorganisms are also discussed using the model predictions.

The effect of RCMF-magnetic therapy apparatus on signal substances was studied. The radioimmunoassay (RIA) suggested that the magnetic field increased beta-endorphin markedly in plasma. ELISA indicated that the magnetic field inhibited vomiting reaction induced by chemotherapy drug, with reversible decrease of serotonin (5-HT) level in brains, small intestine tissue and serum. Furthermore, the bioeffect of magnetic fields on 5-HT level presented a typical window effect and post-effect, and the inhibitory effect of magnetic field on the emesis was parallel to the decrease level of 5-HT. This result implied that the decrease of 5-HT might be the basis of rotating constant magnetic field (RCMF) inhibiting drug-induced emesis. The nitric acid reductase-spectrophotometry and nicotinamide adenine dinucleotide-diaphorase/arginine-vasopressin (AVP) cytochemistry technique showed that the magnetic field induced nitric oxide (NO) increase in hypothalamus and the high NO(A) level lasted for 3 hours. The results suggested that NO(A) increases after the treatment of the magnetic field in hypothalamus, which may result from strong expression of NO-ergic neuron in paraventricular hypothalamic nucleus (PVN), periventricular hypothalamic nucleus (PEN) and supraoptic nucleus (SON). The coexistence of NO and AVP may play an important role in the regulation of endocrine and neuroendocrine by the magnetic field. And our data also confirmed that the magnetic field increased the content of NO so strongly that high NO level lasted for 3 hours, also made neuropeptide Y (NPY) cell in medulla stained heavily.

To investigate the trajectory of depressive symptoms among adolescents exposed to the Wenchuan earthquake as well as predictors after the earthquake.A cohort of students (N = 1,573) in the 7th and 10th grades from Dujiangyan city was followed-up periodically for 2 years. Participants were assessed at 6, 12, 18, and 24 months after the earthquake. Adolescents completed the Depression Self-rating Scale for Children, Adolescent Self-Rating Life Event Checklist, Resilience Scale, and earthquake exposure questionnaire.The prevalence rates of depressive symptoms at 6, 12, 18 and 24 months were 27.4, 41, 31.9, and 38.3 %, respectively. The number of adolescents who kept no depressive symptoms and persistent depressive symptoms at each stage was stable, accounted for almost 50 and 20 % of the total, respectively. Adolescents turning no depressive symptoms to depressive symptoms were mostly in 6-12 months, followed by 18-24 months. Additionally, girls (OR 1.24-1.37), post-disaster negative life events (OR for high vs. low = 5.54-15.06), resilience (OR for low vs. high = 9.40-13.69), and depressive symptoms at previous stage (OR 4.96-6.03) had a long-term effect on depressive symptoms, while the impact of earthquake exposure diminished with the passage of time and could not predict depressive symptoms after one and a half years after the earthquake.Among adolescent survivors, the resistance and persistence of depressive symptoms were common. Moreover, depressive symptoms tended to outbreak close to the anniversary date, showing the anniversary reaction. Adolescent girls, adolescents who encountered high levels of life events, had low levels of resilience and a history of depressive symptoms should be provided with psychological intervention.

We have investigated the effects of magnetic fields on nitric acid (NO) and neuropeptide Y (NPY) on adrenal glands of the rat using NO nitric acid reductase-spec-trophotometry and histochemistry techniques. We found that all cellular layers of the adrenal cortex, including zona glomerulosa, zona fasciculata and zona reticularis were stained by NADPH-d, and some chromaffin cells of the medulla were positive for NPY. Furthermore, magnetic fields increased NO so strongly that high NO levels could be maintained for several hours, as well as some neuroganglion cells in medulla that were double-stained for NPY and NADPH-d. Our data showed that the magnetic field can regulate endocrine and neuroendocrine directly by some action on parenchyma cells, or indirectly by action to NO-ergic, NPY-ergic neurons in the adrenal gland.