The Experts below are selected from a list of 193749 Experts worldwide ranked by ideXlab platform

Bertold Hock - One of the best experts on this subject based on the ideXlab platform.

  • a new concept for the bioeffects related analysis of xenoestrogens hyphenation of Receptor assays with lc ms
    Fresenius Journal of Analytical Chemistry, 1999
    Co-Authors: Martin Seifert, Stefanie Haindl, Gerald Brennerweis, Michael Nusser, Ursula Obst, Bertold Hock
    Abstract:

    The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In this work the hyphenation of an Enzyme-Linked Receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS) for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation of biomolecular interaction and chemical analysis are discussed: the on-line coupling of Receptor-affinity chromatography (RAC) to LC-MSMS and the direct measurement of Receptor-ligand complexes by LC-MSMS.

  • Development of an enzyme linked Receptor assay (ELRA) for estrogens and xenoestrogens
    Analytica Chimica Acta, 1999
    Co-Authors: Martin Seifert, Stefanie Haindl, Bertold Hock
    Abstract:

    Abstract Enzyme-Linked Receptor assays (ELRAs) represent a bioeffects-related approach to the analysis of xenoendocrines. The Receptor assay employs the same principles as competitive immunoassays based on ligand–protein interactions. However, Receptor binding implicates a biological effect, either agonistic or antagonistic. In this paper, the human estrogen Receptor α was used for binding estrogenic substances in environmental samples. A BIAcore biosensor was applied for Receptor characterisation and assay development. The ELRA was calibrated using different estrogens and xenoestrogens including o , p ′-isomers of DDT and its metabolites. It yielded a detection limit up to 0.1 μg l −1 for 17β-estradiol. A close correlation was obtained when ELRA cross-reactivity data of different estrogenic and non-estrogenic substances were compared with data published for radioReceptor assays. Real-water samples were spiked with 17β-estradiol and measured with the ELRA. Recoveries between 90% and 100% and no significant matrix effects were observed. The ELRA can be used for cost-effective and high throughput screening of estrogens and xenoestrogens in environmental samples.

Yoshihiro Yoshihara - One of the best experts on this subject based on the ideXlab platform.

  • an adenosine Receptor for olfaction in fish
    Current Biology, 2017
    Co-Authors: Noriko Wakisaka, Nobuhiko Miyasaka, Tetsuya Koide, Miwa Masuda, Towako Hirakikajiyama, Yoshihiro Yoshihara
    Abstract:

    Nucleotides released from food sources into environmental water are supposed to act as feeding cues for many fish species. However, it remains unknown how fish can sensitively detect those nucleotides. Here we discover a novel olfactory mechanism for ATP sensing in zebrafish. Upon entering into the nostril, ATP is efficiently converted into adenosine through enzymatic reactions of two ecto-nucleotidases expressed in the olfactory epithelium. Adenosine subsequently activates a small population of olfactory sensory neurons expressing a novel adenosine Receptor A2c that is unique to fishes and amphibians. The information is then transmitted to a single glomerulus in the olfactory bulb and further to four regions in higher olfactory centers. These results provide conclusive evidence for a sophisticated Enzyme-Linked Receptor mechanism underlying detection of ATP as a food-derived attractive odorant linking to foraging behavior that is crucial and common to aquatic lower vertebrates.

Martin Seifert - One of the best experts on this subject based on the ideXlab platform.

  • a new concept for the bioeffects related analysis of xenoestrogens hyphenation of Receptor assays with lc ms
    Fresenius Journal of Analytical Chemistry, 1999
    Co-Authors: Martin Seifert, Stefanie Haindl, Gerald Brennerweis, Michael Nusser, Ursula Obst, Bertold Hock
    Abstract:

    The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In this work the hyphenation of an Enzyme-Linked Receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS) for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation of biomolecular interaction and chemical analysis are discussed: the on-line coupling of Receptor-affinity chromatography (RAC) to LC-MSMS and the direct measurement of Receptor-ligand complexes by LC-MSMS.

  • Development of an enzyme linked Receptor assay (ELRA) for estrogens and xenoestrogens
    Analytica Chimica Acta, 1999
    Co-Authors: Martin Seifert, Stefanie Haindl, Bertold Hock
    Abstract:

    Abstract Enzyme-Linked Receptor assays (ELRAs) represent a bioeffects-related approach to the analysis of xenoendocrines. The Receptor assay employs the same principles as competitive immunoassays based on ligand–protein interactions. However, Receptor binding implicates a biological effect, either agonistic or antagonistic. In this paper, the human estrogen Receptor α was used for binding estrogenic substances in environmental samples. A BIAcore biosensor was applied for Receptor characterisation and assay development. The ELRA was calibrated using different estrogens and xenoestrogens including o , p ′-isomers of DDT and its metabolites. It yielded a detection limit up to 0.1 μg l −1 for 17β-estradiol. A close correlation was obtained when ELRA cross-reactivity data of different estrogenic and non-estrogenic substances were compared with data published for radioReceptor assays. Real-water samples were spiked with 17β-estradiol and measured with the ELRA. Recoveries between 90% and 100% and no significant matrix effects were observed. The ELRA can be used for cost-effective and high throughput screening of estrogens and xenoestrogens in environmental samples.

Stefanie Haindl - One of the best experts on this subject based on the ideXlab platform.

  • a new concept for the bioeffects related analysis of xenoestrogens hyphenation of Receptor assays with lc ms
    Fresenius Journal of Analytical Chemistry, 1999
    Co-Authors: Martin Seifert, Stefanie Haindl, Gerald Brennerweis, Michael Nusser, Ursula Obst, Bertold Hock
    Abstract:

    The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In this work the hyphenation of an Enzyme-Linked Receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS) for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation of biomolecular interaction and chemical analysis are discussed: the on-line coupling of Receptor-affinity chromatography (RAC) to LC-MSMS and the direct measurement of Receptor-ligand complexes by LC-MSMS.

  • Development of an enzyme linked Receptor assay (ELRA) for estrogens and xenoestrogens
    Analytica Chimica Acta, 1999
    Co-Authors: Martin Seifert, Stefanie Haindl, Bertold Hock
    Abstract:

    Abstract Enzyme-Linked Receptor assays (ELRAs) represent a bioeffects-related approach to the analysis of xenoendocrines. The Receptor assay employs the same principles as competitive immunoassays based on ligand–protein interactions. However, Receptor binding implicates a biological effect, either agonistic or antagonistic. In this paper, the human estrogen Receptor α was used for binding estrogenic substances in environmental samples. A BIAcore biosensor was applied for Receptor characterisation and assay development. The ELRA was calibrated using different estrogens and xenoestrogens including o , p ′-isomers of DDT and its metabolites. It yielded a detection limit up to 0.1 μg l −1 for 17β-estradiol. A close correlation was obtained when ELRA cross-reactivity data of different estrogenic and non-estrogenic substances were compared with data published for radioReceptor assays. Real-water samples were spiked with 17β-estradiol and measured with the ELRA. Recoveries between 90% and 100% and no significant matrix effects were observed. The ELRA can be used for cost-effective and high throughput screening of estrogens and xenoestrogens in environmental samples.

David Margulies - One of the best experts on this subject based on the ideXlab platform.