TY - CONF A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Jung, Christian A1 - Schröter-Kermani, C. A1 - Nehls, Irene T1 - Time courses of HBCD levels and enantiomeric signatures in herring gull eggs from the German coast T2 - Dioxin 2010 - 30th International symposium on halogenated persistent organic pollutants CY - San Antonio, TX, USA DA - 2010-09-12 PY - 2010 UR - http://www.dioxin20xx.org/pdfs/2010/10-1112.pdf N1 - Serientitel: Organohalogen Compounds – Series title: Organohalogen Compounds VL - 72 SP - 255 EP - 258 AN - OPUS4-23167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Jung, Christian A1 - Schröter-Kermani, C. A1 - Bremser, Wolfram A1 - Nehls, Irene T1 - Temporal trend (1988-2008) of hexabromocyclododecane enantiomers in herring gull eggs from the german coastal region N2 - 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. KW - Brominated flame retardant KW - Chiral separation KW - HPLC-ESI-MS/MS KW - Enantiomer-specific bioaccumulation PY - 2011 U6 - https://doi.org/10.1016/j.chemosphere.2010.12.047 SN - 0045-6535 SN - 0366-7111 VL - 83 IS - 2 SP - 161 EP - 167 PB - Elsevier Science CY - Kidlington, Oxford AN - OPUS4-23351 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, M. A1 - Durmaz, V. A1 - Becker, Roland A1 - Esslinger, Susanne T1 - Predictive identification of Pentabromocyclododecene (PBCD) isomers with high binding affinity to hTTR N2 - 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. T2 - Dioxin 2009 - 29th International symposium on halogenated persistent organic pollutants / Organohalogen compounds CY - Beijing, China DA - 2009-08-23 KW - Flammschutzmittel KW - Thyroxin KW - Molecular modeling PY - 2009 UR - http://www.dioxin20xx.org/pdfs/2009/09-54.pdf VL - 71 SP - 000247 EP - 000252 CY - Beijing, China AN - OPUS4-20980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharkoi, O. A1 - Becker, Roland A1 - Esslinger, Susanne A1 - Weber, M. A1 - Nehls, Irene T1 - Predicting sites of cytochrome P450-mediated hydroxylation applied to CYP3A4 and hexabromocyclododecane N2 - 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. KW - Predicting sites of metabolism KW - Cytochrome P450 KW - Hydroxylation KW - Metabolism of HBCD PY - 2015 U6 - https://doi.org/10.1080/08927022.2014.898845 SN - 0892-7022 SN - 1029-0435 VL - 41 IS - 7 SP - 538 EP - 546 PB - Gordon and Breach CY - New York, NY AN - OPUS4-30492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharkoi, O. A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Weber, M. A1 - Nehls, Irene T1 - Phase I oxidation of alpha- and gamma-hexabromocyclododecane by cytochrome P450 enzymes: simulation of the steroisomerism of hydroxylated metabolites T2 - DIOXIN 2011 CY - Brussels, Belgium DA - 2011-08-21 KW - Bromierte Falmmschutzmittel KW - Hexabromcyclododecan KW - Cytochrom KW - Metaboliten KW - HPLC KW - Simulation PY - 2011 UR - http://www.dioxin20xx.org/pdfs/2011/1810.pdf SN - 1026-4892 VL - 73 SP - 730 EP - 733 AN - OPUS4-27263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Maul, Ronald A1 - Nehls, Irene T1 - Hexabromocyclododecane enantiomers: microsomal degradation and patterns of hydroxylated metabolites N2 - 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. KW - Brominated flame retardant KW - Cytochromes KW - Phase I metabolism KW - Hydroxylation KW - HPLC-MS/MS PY - 2011 U6 - https://doi.org/10.1021/es1039584 SN - 0013-936X SN - 1520-5851 VL - 45 IS - 9 SP - 3938 EP - 3944 PB - ACS Publ. CY - Washington, DC AN - OPUS4-23837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Köppen, Robert A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Nehls, Irene T1 - Hexabromcyclododecan in heimischen Süßwasserfischen N2 - 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. PY - 2009 U6 - https://doi.org/10.1002/nadc.200967612 SN - 1439-9598 SN - 1521-3854 VL - 57 IS - 9 SP - 901 EP - 904 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-19911 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Maul, Ronald A1 - Nehls, Irene T1 - Hexabromcyclododecan - Untersuchungen zum Phase I Metabolismus PY - 2010 SN - 0934-3504 SN - 1865-5084 VL - 22 IS - 4 SP - 364 PB - Springer CY - Heidelberg AN - OPUS4-22907 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Müller-Belecke, A. A1 - Bremser, Wolfram A1 - Jung, Christian A1 - Nehls, Irene T1 - HBCD stereoisomer pattern in mirror carps following dietary exposure to pure Gamma-HBCD enantiomers KW - Enantiomer-specific determination KW - HPLC-MS/MS KW - Brominated flame retardant KW - Fish feeding experiment KW - Enantiomer fraction KW - Bioisomerization PY - 2010 U6 - https://doi.org/10.1021/jf101469q SN - 0021-8561 SN - 1520-5118 VL - 58 IS - 17 SP - 9705 EP - 9710 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-23173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Nehls, Irene T1 - HBCD isomers: degradation rates and hydroxylated products from microsome incubation experiments T2 - Dioxin 2010 - 30th International symposium on halogenated persistent organic pollutants CY - San Antonio, TX, USA DA - 2010-09-12 PY - 2010 UR - http://www.dioxin20xx.org/pdfs/2010/10-1113.pdf N1 - Serientitel: Organohalogen Compounds – Series title: Organohalogen Compounds VL - 72 SP - 259 EP - 262 AN - OPUS4-23168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Esslinger, Susanne A1 - Köppen, Robert A1 - Becker, Roland A1 - Nehls, Irene T1 - Enantiomerenspezifischer Vergleich von HBCD-Gehalten maritimer Lebewesen zweier norwegischer Fjorde PY - 2010 SN - 0934-3504 SN - 1865-5084 VL - 22 IS - 4 SP - 441 PB - Springer CY - Heidelberg AN - OPUS4-22906 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Köppen, Robert A1 - Becker, Roland A1 - Esslinger, Susanne A1 - Nehls, Irene T1 - Enantiomer-specific analysis of hexabromocyclododecane in fish from Etnefjorden (Norway) N2 - 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. KW - Flame retardant KW - Diastereomers KW - Chiral separation KW - Bioaccumulation KW - Enantiomeric fraction PY - 2010 U6 - https://doi.org/10.1016/j.chemosphere.2010.06.019 SN - 0045-6535 SN - 0366-7111 VL - 80 IS - 10 SP - 1241 EP - 1245 PB - Elsevier Science CY - Kidlington, Oxford AN - OPUS4-22377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Müller-Belecke, A. A1 - Jung, Christian A1 - Nehls, Irene T1 - Bioisomerization of HBCD: Results of feeding experiments with pure Gamma-HBCD enantiomers N2 - 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. T2 - Dioxin 2009 - 29th International symposium on halogenated persistent organic pollutants / Organohalogen compounds CY - Beijing, China DA - 2009-08-23 PY - 2009 UR - http://www.dioxin20xx.org/pdfs/2009/09-103.pdf VL - 71 SP - 000487 EP - 000492 CY - Beijing, China AN - OPUS4-21187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -