Characterization of the metabolism of eupalinolide A and B by carboxylesterase and cytochrome P450 in human liver microsomes

Eupalinolide A (EA; Z-configuration) and eupalinolide B (EB; E-configuration) are bioactive cis-trans isomers isolated from Eupatorii Lindleyani Herba that exert anti-inflammatory and antitumor effects. Although one pharmacokinetic study found that the metabolic parameters of the isomers were different in rats, metabolic processes relevant to EA and EB remain largely unknown. Our preliminary findings revealed that EA and EB are rapidly hydrolyzed by carboxylesterase. Here, we investigated the metabolic stability and enzyme kinetics of carboxylesterase-mediated hydrolysis and cytochrome P450 (CYP)-mediated oxidation of EA and EB in human liver microsomes (HLMs). We also explored differences in the hydrolytic stability of EA and EB in human liver microsomes and rat liver microsomes (RLMs). Moreover, cytochrome P450 reaction phenotyping of the isomers was performed via in silico methods (i.e., using a quantitative structure-activity relationship model and molecular docking) and confirmed using human recombinant enzymes. The total normalized rate approach was considered to assess the relative contributions of five major cytochrome P450s to EA and EB metabolism. We found that EA and EB were eliminated rapidly, mainly by carboxylesterase-mediated hydrolysis, as compared with cytochrome P450-mediated oxidation. An inter-species difference was observed as well, with faster rates of EA and EB hydrolysis in rat liver microsomes. Furthermore, our findings confirmed EA and EB were metabolized by multiple cytochrome P450s, among which CYP3A4 played a particularly important role

Nanocone Decorated ZnO Microspheres Exposing the (0001) Plane and Enhanced Photocatalytic Properties

WZ thanks EPSRC for a platform grant (No. EP/K015540/1) and financial support to the Electron Microscopy Laboratory (No. EP/F019580/1)ZnO spherical particles exposing only the (0001) planes were prepared by an established solvothermal method using a water‒ethylene glycol (EG) mix as a solvent. It was found that poorly crystalline nanoparticles formed first, followed by their aggregation into microspheres consisting of crystallites embedded in ethylene glycol and precursor molecules/ions. The grown up nanocrystallites and nanocones in the microspheres are all radially aligned. The possible formation mechanisms, in particular, the roles of water molecules, ethylene glycol and the intrinsic dipolar field of ZnO crystals, are discussed. X-ray photoelecton spectroscopy (XPS) experiments indicated the spherical particles were terminated solely by zinc atoms. Brunauer-Emmett-Teller (BET) measurements in conjunction with the degradation of methylene blue (MB) dye data demonstrated that the photocatalytic performance of the ZnO spheres depended on the growth time and was significantly improved compared to traditional ZnO nanorods. This study is a rare example which combines nanostructural characterisation of ZnO particles terminated with a single (0001) plane of known Zn2+-polarity with their photocatalytic performance.PostprintPeer reviewe

Kv7.4 Channel Contribute to Projection-Specific Auto-Inhibition of Dopamine Neurons in the Ventral Tegmental Area

Dopaminergic neurons in the ventral tegmental area (VTA) encode behavioral patterns important in reward and drug addiction as well as in emotional disorders. These functions of dopamine neurons are directly related to the release of dopamine in the targeted regions of the brain which are, thus, controlled by the excitability of dopamine neurons. One mechanism for modulation of dopamine neuronal excitability is mediated by the auto dopamine type 2 (D2) receptors, through activation of a Kir3/GIRK K+ channel which inhibits the firing of dopamine neurons. In this study, we provide evidence that Kv7.4, in addition to Kir3.2 channels, contributes to dopamine (DA)-mediated auto-inhibition of DA activity projecting to NAc and to basolateral amygdale (BLA). Furthermore, we demonstrate that D2 receptors enhance Kv7.4 currents through Gi/o protein and redox-dependent cellular pathway. Finally, we show this D2 mediated auto-inhibition is blunted in a social defeat mice model of depression, a phenomenon that may contribute to the altered excitability of VTA DA neurons in depressed animals. These results provide a new perspective for understanding the molecular mechanism of the excitability of VTA DA neurons and for potential new strategies against mental disorders involving altered excitability of DA neurons, such as major depression and drug addictions

Easy and green route towards nanostructured ZnO as active sensing material with unexpected H2S dosimeter-type behaviour

Nanostructured ZnO particles were prepared through a straightforward, quick and low\u2010temperature synthesis route involving coprecipitation of the metal precursor salts with oxalic acid, followed by hydrothermal treatment at 135 or 160 \ub0C. The synthesised nanostructured powders were thoroughly characterised by a wide array of analytical techniques from the morphological (Scanning Electron Microscopy \u2013SEM\u2010, Transmission Electron Microscopy \u2010TEM\u2010, Energy\u2010dispersive X\u2010ray Spectroscopy \u2010EDXS\u2010), structural (Powder X\u2010Ray Diffraction \u2010PXRD\u2010, Selected Area Electron Diffraction \u2010SAED\u2010), compositional (X\u2010ray Photoelectron Spectroscopy \u2010XPS\u2010) and physical (thermal stability) point of view. As far as functional applications are concerned, the powders were tested as gas sensor materials for H2S detection. Thereby these ZnO particles show unexpected gas dosimeter behaviour at 150 \ub0C. Based on these observations and on a comparison with literature a new model for the interaction of ZnO nanostructures with H2S is proposed

FMD vaccine matching: Inter laboratory study for improved understanding of r1 values

Foot-and-mouth disease virus (FMDV) is a highly variable RNA virus existing as seven different serotypes. The antigenic variability between and within serotypes can limit the cross-reactivity and therefore the in vivo cross-protection of vaccines. Selection of appropriate vaccine strains is crucial in the control of FMD. Determination of indirect relationships (r1-value) between potential vaccine strains and field strains based on antibody responses against both are routinely used for vaccine matching purposes. Aiming at the investigation of the repeatability, reproducibility and comparability of r1-value determination within and between laboratories and serological tests, a small scale vaccine matching ring test for FMDV serotype A was organized. Well-characterized serum pools from cattle vaccinated with a monovalent A24/Cruzeiro/Brazil/55 (A24) FMD vaccine with known in vivo protection status (homologous and heterologous) were distributed to four laboratories to determine r1-values for the heterologous FMD strains A81/Argentina/87, A/Argentina/2000 and A/Argentina/2001 using the virus neutralization tests (VNT) and liquid phase blocking ELISA (LPBE). Within laboratories, the repeatability of r1-value determination was high for both antibody assays. VNT resulted in reproducible and comparable r1-values between laboratories, indicative of a lack of antigenic relatedness between the A24 strain and the heterologous strains tested in this work, thus corresponding to some of the in vivo findings with these strains. Using LPBE, similar trends in r1-values were observed in all laboratories, but the overall reproducibility was lower than with VNT. Inconsistencies between laboratories may at least in part be attributed to differences in LPBE protocols as well as the in preexisting information generated in each laboratory (such as antibody titer-protection correlation curves). To gain more insight in the LPBE-derived r1-values standard bovine control sera were included in the antibody assays performed in each laboratory and a standardization exercise was performed.Fil: Willems, Tom. No especifíca;Fil: De Vleeschauwer, Annebel. No especifíca;Fil: Pérez Filgueira, Daniel Mariano. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Virologia E Innovaciones Tecnologicas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Virologia E Innovaciones Tecnologicas.; ArgentinaFil: Li, Yanmin. No especifíca;Fil: Ludi, Anna. No especifíca;Fil: Lefebvre, David. No especifíca;Fil: Wilsden, Ginette. No especifíca;Fil: Statham, Bob. No especifíca;Fil: Haas, Bernd. Federal Research Institute for Animal Health; AlemaniaFil: Mattion, Nora Marta. Ministerio de Produccion y Trabajo. Secretaria de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virologia Animal. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Virologia Animal.; ArgentinaFil: Robiolo, Blanca. Ministerio de Produccion y Trabajo. Secretaria de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virologia Animal. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Virologia Animal.; ArgentinaFil: Beascoechea Perez, Claudia. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Maradei, Eduardo. Ministerio de Agricultura, Ganadería, Pesca y Alimento. Servicio Nacional de Sanidad y Calidad Agroalimentaria; ArgentinaFil: Smitsaart, Eliana. Biogénesis Bagó; ArgentinaFil: la Torre, Jose Leonardo. Ministerio de Produccion y Trabajo. Secretaria de Gobierno de Agroindustria. Servicio Nacional de Sanidad y Calidad Agroalimentaria. Centro de Virologia Animal. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Virologia Animal.; ArgentinaFil: De Clercq, Kris. No especifíca

PCP-B class pollen coat proteins are key regulators of the hydration checkpoint in Arabidopsis thaliana pollen-stigma interactions

The establishment of pollen–pistil compatibility is strictly regulated by factors derived from both male and female reproductive structures. Highly diverse small cysteine-rich proteins (CRPs) have been found to play multiple roles in plant reproduction, including the earliest stages of the pollen–stigma interaction. Secreted CRPs found in the pollen coat of members of the Brassicaceae, the pollen coat proteins (PCPs), are emerging as important signalling molecules that regulate the pollen–stigma interaction. Using a combination of protein characterization, expression and phylogenetic analyses we identified a novel class of Arabidopsis thaliana pollen-borne CRPs, the PCP-Bs (for pollen coat protein B-class) that are related to embryo surrounding factor (ESF1) developmental regulators. Single and multiple PCP-B mutant lines were utilized in bioassays to assess effects on pollen hydration, adhesion and pollen tube growth. Our results revealed that pollen hydration is severely impaired when multiple PCP-Bs are lost from the pollen coat. The hydration defect also resulted in reduced pollen adhesion and delayed pollen tube growth in all mutants studied. These results demonstrate that AtPCP-Bs are key regulators of the hydration ‘checkpoint’ in establishment of pollen–stigma compatibility. In addition, we propose that interspecies diversity of PCP-Bs may contribute to reproductive barriers in the Brassicaceae