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@ARTICLE{Gabriel:432,
      author       = {Gabriel, F. L. P. and Routledge, E.J. and Heidlberger, A.
                      and Rentsch, D. and Günther, K. and Giger, W. and Sumpter,
                      J.P. and Kohler, H.-P.E.},
      title        = {{I}somer-specific degradation and endocrine disrupting
                      activity of nonylphenols},
      journal      = {Environmental Science $\&$ Technology},
      volume       = {42},
      issn         = {0013-936X},
      address      = {Columbus, Ohio},
      publisher    = {American Chemical Society},
      reportid     = {PreJuSER-432},
      pages        = {6399 - 6408},
      year         = {2008},
      note         = {This research was supported by the Swiss National Science
                      Foundation within the framework of the National Research
                      Programme NFP50 "Endocrine Disruptors: Relevance to Humans,
                      Animals, and Ecosystems". We thank Dr. Ian Purvis and others
                      at GlaxoSmithKline for kindly supplying the genetically
                      modified yeast strain.},
      abstract     = {Degradation of technical nonylphenol by Sphingobium
                      xenophagum Bayram led to a significant shift in the isomers
                      composition of the mixture. By means of gas
                      chromatography-mass spectrometry, we could observe a strong
                      correlation between transformation of individual isomers and
                      their a-substitution pattern, as expressed by their
                      assignment to one of six mass spectrometric groups. As a
                      rule, isomers with less bulkiness at the a-carbon and those
                      with an optimally sized main alkyl chain (4-6 carbon atoms)
                      were degraded more efficiently. By mass spectrometric
                      analysis, we identified the two most recalcitrant main
                      isomers of the technical mixture (Group4) as
                      4-(1,2-dimethyl-1-propylbutyl) phenols (NP193a and NP193b,
                      which are diastereomers with a bulky alpha-CH3,
                      alpha-CH(CH3)C2H5 substitution. Our experiments with strain
                      Bayram show that the selective enrichment of isomers with
                      bulky a-substitutions observed in nonylphenol fingerprints
                      of natural systems can be caused by microbial
                      ipso-hydroxylation. Based on the yeast estrogen assay (YES),
                      we established an estrogenicity ranking with a variety of
                      single isomers and compared it to rankings obtained with
                      different reporter cell systems. Structure-activity
                      relationships derived from these data suggest that Group 4
                      isomers have a high estrogenic potency. This indicates a
                      substantial risk that enrichment of highly estrogenic
                      isomers during microbial degradation by ipso-substitution
                      will increase the specific estrogenicity of aging material.},
      keywords     = {J (WoSType)},
      cin          = {ICG-3},
      ddc          = {050},
      cid          = {I:(DE-Juel1)ICG-3-20090406},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Engineering, Environmental / Environmental Sciences},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000258883300019},
      pubmed       = {pmid:18800507},
      doi          = {10.1021/es800577a},
      url          = {https://juser.fz-juelich.de/record/432},
}