Wongslater8469

In the present study, chitosan-containing nanocomposites were investigated as new antibacterial agents. Magnetite (Fe3O4) nanoparticles (NPs) as well as chitosan (CS)/Fe3O4 nanocomposites (NCs) and graphene(Gr)/CS/Fe3O4 NCs were synthesized by simple hydrothermal method. Their composition, structure and morphology were studied, followed by the evaluation of their antibacterial activity against ESBL-producing and gram-negative P. aeruginosa and K. pneumoniae bacterial strains. The Gr/CS/Fe3O4 NCs showed significantly higher antibacterial activity compared to Fe3O4 NPs and CS/Fe3O4 NCs (105 and 69 % higher against P. aeruginosa as well as 91 and 77 % higher against K. pneumoniae, respectively). The minimum inhibitory concentration (MIC) of Gr/CS/Fe3O4 NCs against P. aeruginosa and K. pneumoniae were 60 and 70 μg/mL, respectively. The synergistic antibacterial activity and facile synthesis of Gr/CS/Fe3O4 NCs suggests their applicability as novel highly efficient antibacterial agents with potential for a wide range of biomedical applications, where antibacterial properties are needed.In this work, we synthesized graphene oxide-silver nanoparticles (GO-AgNPs) hybrids by one-pot method. Since there are relatively few reports on whether GO-AgNPs bind and change the structure and function of trypsin, A variety of methods were employed to systematically characterize the molecular interaction between GO-AgNPs and trypsin. Results exhibited that GO-AgNPs bound with trypsin to form a ground state complex. GO-AgNPs had higher adsorption capacity for trypsin compared with single GO. Langmuir-Blodgett assembly method was used to confirm that AgNPs did not interfere with the adsorption of trypsin by GO. The secondary structure and the microenvironment of amino acid residues of trypsin were altered after interacting with GO-AgNPs. In addition, GO-AgNPs can enhance the activity of trypsin and promote the hydrolysis of bovine serum protein (BSA) by trypsin. These findings provide important support for the application of GO-based nanocomposites in the efficient immobilization of enzymes.HBV capsid assembly has been regarded as an attractive potential target for anti-HBV therapy. In this study, we discovery the Novel HBV capsid assembly modulators (CAMs) through structure-based virtual screening and bioassays. A total of 16 structurally diverse compounds were purchased and assayed, including three compounds with inhibition rate > 50% at 20 μM. Further lead optimization based on the most potent compound II-1-7 (EC50 = 5.6 ± 0.1 µM) were performed by using substructure searching strategy, resulting in compound II-2-9 with an EC50 value of 1.8 ± 0.6 μM. In bimolecular fluorescence complementation (BiFC) assay, compound II-2-9 inhibited the HBV by disrupting the HBV capsid interactions. In summary, this study provides a highly efficient way to discover novel CAMs, and 2-aryl-4-quinolyl amide derivatives could serve as the starting point for development of novel anti-HBV drugs.Limited studies examined the associations of prenatal exposure to particulate matter (PM) and children's growth with inconsistent results, and no study focused on PM1. We matched a birth cohort (10,547 children) with daily PM1 and PM2.5 concentrations by maternal home addresses. Air pollution concentrations were predicted by satellite remote sensing data, meteorological factors, and land use information. The weight and length of children in the birth cohort were measured at approximately one year old. We calculated the Z-score of weight for length (WFL) and body mass index (BMI) and then defined overweight and obesity (OWOB) based on WHO Standards. Generalized linear regression and modified Poisson regression were used to identify the association of prenatal exposure to PM1 or PM2.5 with anthropometric measurements and risk of OWOB. We also determined the mediation effect of preterm birth on the associations. Results showed that a 10 μg/m3 increase in prenatal exposure to PM1 and PM2.5 was significantly assoce to PM1 and PM2.5 increased WFL, BMI Z-scores and higher risk of OWOB for one-year-old children. The associations were partially mediated by preterm birth. These findings call for the urgent action on air pollution regulation to protect early-life health among children.Five pairs of undescribed naphthalenone derivative enantiomers, xylarinaps A-E, including one pair of indole naphthalenones and four pairs of naphthalene-naphthalenone dimers, were isolated from the ethyl acetate extracts of the solid fermentation of Xylaria nigripes, which has been used as a traditional Chinese medicinal fungus for the treatment of insomnia, trauma, and depression. The structures of these enantiomers were elucidated based on comprehensive spectroscopic analysis, including NMR and HRESIMS. Their absolute configurations were assigned by the experimental and calculated ECD data. The neuroprotective effects of all the compounds against damage to PC12 cells by oxygen and glucose deprivation (OGD) were evaluated by an in vitro bioassay. The results revealed that xylarinaps A, B, D, and E significantly enhanced cell viability, decreased the levels of malondialdehyde (MDA), increased the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as further markedly inhibiting apoptosis, which indicated that these results could be the mode of action of their neuroprotective effect.The Lamiaceae plant Ajuga forrestii Diels is a traditional Chinese herbal medicine with abundant glandular trichomes (GTs), but their chemistry and biological functions remain uninvestigated. Here, a panel of six highly functionalized neo-clerodane diterpenoids was localized to the peltate GTs of A. forrestii using laser microdissection coupled with HPLC analysis, indicating that the GTs of A. forrestii are an excellent material for the elucidation of the yet unclear biosynthetic pathway of natural neo-clerodane diterpenoids. In addition, four undescribed neo-clerodane diterpenoids with an acyclic C-9 side chain including two pairs of 11 mixture of inseparable diastereomers, ajuforrestins D-G, were isolated from the fresh leaves of A. forrestii together with six known compounds. The structures of the undescribed compounds were elucidated by spectroscopic (including 1D and 2D NMR and HR-ESI-MS) analyses. Biological assays indicated that the major GT compound ajugacumbin B and undescribed ajuforrestins D/E showed antifeedant activity against Helicoverpa armigera, suggesting that neo-clerodanes in A. forrestii should be involved in plant defence against insects. Moreover, the abietane diterpenoid ajuforrestin B exhibited significant anti-inflammatory activity on the secretion of interleukin-2 (IL-2) and cytotoxicity against three cancer cell lines, NCI-H1975, HepG2 and MCF-7, suggesting that ajuforrestin B could positively contribute to the therapeutic effects of this traditional Chinese medicine.The glycogen synthase kinases 3 family (GSK3s/SKs; serine/threonine protein kinases) is conserved throughout eukaryotic evolution from yeast to plants and mammals. We studied a plant SK kinase from Lotus japonicus (LjSK1), previously implicated in nodule development, by enzyme kinetics and mutagenesis studies to compare it to mammalian homologues. Using a phosphorylated peptide as substrate, LjSK1 displays optimum kinase activity at pH 8.0 and 20 °C following Michaelis-Menten kinetics with Km and Vmax values of 48.2 μM and 111.6 nmol/min/mg, respectively, for ATP. Mutation of critical residues, as inferred by sequence comparison to the human homologue GSK3β and molecular modeling, showed a conserved role for Lys167, while residues conferring substrate specificity in the human enzyme are not as significant in modulating LjSK1 substrate specificity. Mutagenesis studies also indicate a regulation mechanism for LjSK1 via proteolysis since removal of a 98 residue long N-terminal segment increases its catalytic efficiency by almost two-fold. In addition, we evaluated the alteration of LjSK1 kinase activity in planta, by overexpressing the mutant variants in hairy-roots and a phenotype in nodulation and lateral root development was verified.Casuarina equisetifolia L. (Casuarinaceae), an actinorhizal plant, exhibits mutualistic symbiosis with Frankia and promotes nitrogen fixation in root nodules. While the exchange of metabolites between host plant and microsymbiont is well understood in legume symbioses, the situation in the symbiosis between nitrogen-fixing Frankia and actinorhizal plants is less clear. In this study, a metabolomic approach was applied to root nodules of mature C. equisetifolia trees, leading to the identification of an undescribed taraxerane-type triterpenoid ester, 3-O-dihydrocoumaroyl β-taraxerol, along with twelve known compounds. An abundant component was tyramine with a content of 2.76 ± 0.315 mg/g FW in mature nodules. Tyramine specifically and abundantly accumulated in mature nitrogen-fixing nodules compared to senescent nodules, stems, leaves, and seeds. In addition, the potential function of tyramine was preliminarily examined and discussed.Cycad cone thermogenesis and its associated volatiles are intimately involved in mediating the behavior of their obligate specialist pollinators. In eastern Australia, thrips in the Cycadothrips chadwicki species complex are the sole pollinators of many Macrozamia cycads. Further, they feed and reproduce entirely in the pollen cones. M. miquelii, found only in the northern range of this genus, is pollinated only by a C. chadwicki cryptic species that is the most distantly related to others in the complex. We examined the volatile profile from M. miquelii pollen and ovulate (receptive and non-receptive) cones to determine how this mediates pollination mechanistically, using GC-MS (gas chromatography-mass spectrometry) and behavioral tests. Monoterpenes comprise the bulk of M. miquelii volatile emissions, as in other Macrozamia species, but we also identified compounds not reported previously in any cycad, including three aliphatic esters (prenyl acetate and two of uncertain identity) and two aliphatic alcohols. The two unknown esters were confirmed as prenyl (3-methylbut-2-enyl) esters of butyric and crotonic ((E))-but-2-enoic) acids after chemical synthesis. Prenyl crotonate is a major component in emissions from pollen and receptive ovulate cones, is essentially absent from non-receptive cones, and has not been reported from any other natural source. In field bioassays, Cycadothrips were attracted only to those volatile treatments containing prenyl crotonate. We discuss M. Protein Tyrosine Kinase inhibitor miquelii cone odorants relative to those of other cycads, especially with respect to prenyl crotonate being a species-specific signal to this northern C. chadwicki cryptic species, and how this system may have diversified.Phytoprotease inhibitors (PI) are important defence compounds produced by plants against microbes and insect herbivory. Oryzacystatins (OCs) are a group of protease inhibitors from Oryza sativa L. that are specific against cysteine protease enzymes. This study revealed the evolutionary relationship of eleven different oryzacystatins from rice and their interaction with cysteine protease enzymes from brown planthopper (BPH) and striped stem borer (SSB). Three-dimensional structure of eleven different oryzacystatins and six cysteine protease enzymes were homologically modelled, and their interaction was analysed to explore the sequence heterogeneity, structural variability and functional significance. OC XI and OC V showed higher docking score and hydrogen bond interaction with all the six tested cysteine protease enzymes. N terminal glycine residue, central conserved QVVXG, C terminal AVVXXXPW regions are involved in interacting with the active site residue of protease enzymes. Substitution of N terminal glycine by any other residue in OC VI significantly reduced the interaction efficiency with cysteine proteases.