Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-20980 Beitrag zu einem Tagungsband Weber, M.; Durmaz, V.; Becker, Roland; Esslinger, Susanne Predictive identification of Pentabromocyclododecene (PBCD) isomers with high binding affinity to hTTR The binding affinities of the six main hexabromocyclododecane (HBCD) stereoisomers and all of their possible 48 allylic pentabromocyclododecene (PBCD) metabolites to the endocrinous human transthyretin receptor (hTTR) were investigated and compared to the natural binder thyroxine, and the two brominated diphenyl ethers BDE-47 and 3-hydroxy-BDE-47. The endocrine disrupting potency was approximated by a combination of two methods: a surface matching with the natural binder thyroxine (T4) followed by approximation of free binding energies for various binding modes within hTTR. The results indicate slightly higher binding affinities for both BDE structures than for T4 itself and similarly high affinities for two trans-configurated PBCD isomers. For many other PBCD isomers, intermediate values were computed, whereas all HBCD diastereomers yielded significantly lower binding affinities. Beijing, China 2009 Dioxin 2009 - 29th International symposium on halogenated persistent organic pollutants / Organohalogen compounds (Proceedings) 71 Dioxin 2009 - 29th International symposium on halogenated persistent organic pollutants / Organohalogen compounds Beijing, China 2009-08-23 2009-08-28 000247 000252 2016-02-19 OPUS4-21187 Beitrag zu einem Tagungsband Esslinger, Susanne; Becker, Roland; Müller-Belecke, A.; Jung, Christian; Nehls, Irene Bioisomerization of HBCD: Results of feeding experiments with pure Gamma-HBCD enantiomers 1,2,5,6,9,10-hexabromocyclododecane (HBCD), a widely used flame retardant, is an ubiquitous contaminant in the environment. Still, only little is known about the distribution and behavior in the environment such as bioaccumulation or biotransformation of HBCD stereoisomers. In order to investigate enrichment and possible bioisomerization of HBCD stereoisomers, Mirror Carps were exposed to pure (+)- and (-)-γ-HBCD, randomly sampled after a predefined specific period and subjected to enantiomer-specific determination of α-, β-, and γ- HBCD. No evidence for the isomerization of HBCD stereoisomers was observed in Mirror Carp fillets. Beijing, China 2009 Dioxin 2009 - 29th International symposium on halogenated persistent organic pollutants / Organohalogen compounds (Proceedings) 71 Dioxin 2009 - 29th International symposium on halogenated persistent organic pollutants / Organohalogen compounds Beijing, China 2009-08-23 2009-08-28 000487 000492 2016-02-19 OPUS4-19911 Zeitschriftenartikel Köppen, Robert; Esslinger, Susanne; Becker, Roland; Nehls, Irene Hexabromcyclododecan in heimischen Süßwasserfischen Hexabromcyclododecan senkt als Flammschutzmittel die Entflammbarkeit von Polymeren und verhindert damit Brände. Als persistente Verbindung reichert es sich in der belebten und in der unbelebten Umwelt an und steht daher im Fokus öffentlichen Interesses. Weinheim Wiley-VCH Verl. Gesellschaft Deutscher Chemiker 2009 Nachrichten aus der Chemie 57 9 901 904 10.1002/nadc.200967612 2016-02-19 OPUS4-22377 Zeitschriftenartikel Köppen, Robert; Becker, Roland; Esslinger, Susanne; Nehls, Irene Enantiomer-specific analysis of hexabromocyclododecane in fish from Etnefjorden (Norway) High-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was applied to sterospecifically quantify the content of α-, β-, and γ-hexabromocyclododecane (HBCD) in six fish species from the Norwegian Etnefjorden. A combination of a β-PM cyclodextrin and an achiral column enabled the paired chromatographic separation of the stereoisomers in the order (-)-α-, (+)-α-, (-)-β-, (+)-β-, (+)-γ- and, (-)-γ-HBCD. The limits of detection were in the range of 6-21 pg g-1 depending on the stereoisomer and the concentrations of α-, β-, and γ-HBCD in fillets ranged from <5.4 ng g-1 to 11.1 µg g-1 lipid weight. α-HBCD enantiomers were throughout dominating, and in most cases the accumulation of the respective first eluted enantiomers ((-)-α-, (-)-β- and (+)-γ-HBCD) was observed. Deviations from the racemic EF-value were considered to be significant if it was outside of the expanded uncertainty range for each of the racemic HBCD-ratios. The composition of HBCD isomers varied between the investigated fish species and the relative high values for the γ-HBCD concentrations for the bottom-dwellers flounder and thorny skate seems to echo the HBCD pattern of ocean sediments. Kidlington, Oxford Elsevier Science 2010 Chemosphere 80 10 1241 1245 10.1016/j.chemosphere.2010.06.019 2016-02-19 OPUS4-23173 Zeitschriftenartikel Esslinger, Susanne; Becker, Roland; Müller-Belecke, A.; Bremser, Wolfram; Jung, Christian; Nehls, Irene HBCD stereoisomer pattern in mirror carps following dietary exposure to pure Gamma-HBCD enantiomers Columbus, Ohio American Chemical Society 2010 Journal of agricultural and food chemistry 58 17 9705 9710 10.1021/jf101469q 2016-02-19 OPUS4-23837 Zeitschriftenartikel Esslinger, Susanne; Becker, Roland; Maul, Ronald; Nehls, Irene Hexabromocyclododecane enantiomers: microsomal degradation and patterns of hydroxylated metabolites The degradation of the enantiomers of α-, β-, and γ-hexabromocyclododecane (HBCD) by phase I metabolism was investigated using induced rat liver microsomes. HBCD isomers were quantified using HPLC-MS/MS (ESI-) after separation on a combination of a reversed phase and a chiral analytical column. The degradation of all six isomers followed first-order kinetics and the estimated half-lives ranged from 6.3 min for both β-HBCD enantiomers to 32.3 min in case of (+)-γ-HBCD. (+)-α- and (-)-γ-HBCD displayed significantly shorter half-lives than their corresponding antipodes. It could be shown that this degradation led to a significant enrichment of the first eluting enantiomers (-)-α- and (+)-γ-HBCD. Individual patterns of mono- and dihydroxylated derivatives obtained from each α- and γ-HBCD enantiomer were seen to be distinctly characteristic. The patterns of monohydroxylated HBCD derivatives detected in liver and muscle tissues of pollack, mackerel and in herring gull eggs were largely similar to those observed in the in vitro experiments with rat liver microsomes. This enabled individual hydroxy-HBCDs to be assigned to their respective parent HBCD enantiomers. Washington, DC ACS Publ. American Chemical Society 2011 Environmental science & technology 45 9 3938 3944 10.1021/es1039584 2016-02-19 OPUS4-27263 Zeitschriftenartikel Scharkoi, O.; Esslinger, Susanne; Becker, Roland; Weber, M.; Nehls, Irene Phase I oxidation of alpha- and gamma-hexabromocyclododecane by cytochrome P450 enzymes: simulation of the steroisomerism of hydroxylated metabolites 2011 Organohalogen compounds 73 DIOXIN 2011 Brussels, Belgium 2011-08-21 2011-08-24 730 733 2016-02-20 OPUS4-23351 Zeitschriftenartikel Esslinger, Susanne; Becker, Roland; Jung, Christian; Schröter-Kermani, C.; Bremser, Wolfram; Nehls, Irene Temporal trend (1988-2008) of hexabromocyclododecane enantiomers in herring gull eggs from the german coastal region Levels of α-, β-, and γ-hexabromocyclododecane (HBCD) were determined in pooled eggs from herring gulls (Larus argentatus) sampled on three bird sanctuaries near the German North Sea coast between 1988 and 2008 (Mellum and Trischen) and the German Baltic Sea coast between 1998 and 2008 (Heuwiese) and archived by the German Environmental Specimen Bank. Pressurized fluid extraction, gel permeation chromatography, and LC–MS/MS using 13C12-labelled isotope standards and a chiral column were applied. α-HBCD was the dominating diastereomer and ranged between 3.7 and 107 ng g-1 lw while β- and γ-HBCD were throughout close to LOQ. The highest α-HBCD concentration was found in eggs from Mellum sampled in the year 2000. Interestingly, HBCD in eggs from the three islands displayed similar time courses with levels increasing to a peak contamination around 2000 and decreasing levels ever since. Chiral signatures of α-HBCD in eggs differed among the islands but indicated a preferential enrichment of the first eluting enantiomer (-)-α-HBCD. Kidlington, Oxford Elsevier Science 2011 Chemosphere 83 2 161 167 10.1016/j.chemosphere.2010.12.047 2016-02-19 OPUS4-30492 Zeitschriftenartikel Scharkoi, O.; Becker, Roland; Esslinger, Susanne; Weber, M.; Nehls, Irene Predicting sites of cytochrome P450-mediated hydroxylation applied to CYP3A4 and hexabromocyclododecane This article describes a simple and quick in silico method for the prediction of cytochrome P450 (CYP)-mediated hydroxylation of drug-like compounds. Testosterone and progesterone, two known substrates of CYP3A4, are used to test the method. Further, we apply the procedure to predict sites of hydroxylation of isomers of the flame retardant hexabromocyclododecane by CYP3A4. Within the method, the compound is rotated in the binding pocket of the cytochrome, so that each hydrogen under consideration is placed near the active centre. Afterwards, short molecular dynamics simulations are provided for each step of the rotation. All steps of the simulation are compared concerning the distances between the hydrogens and the active centre and the corresponding energies. The computational results correlate well with experimental results. New York, NY Gordon and Breach 2015 Molecular simulation 41 7 538 546 10.1080/08927022.2014.898845 2016-02-20