title: Hydroxylated metabolites of 4-monochlorobiphenyl and its metabolic pathway in whole poplar plants.
abstract: 4-Monochlorobiphenyl (CB3), mainly an airborne pollutant, undergoes rapid biotransformation to produce hydroxylated metabolites (OH-CB3s). However, up to now, hydroxylation of CB3 has not been studied in living organisms. In order to explore the formation of hydroxylated metabolites of CB3 in whole plants, poplars (Populus deltoides x nigra, DN34) were exposed to CB3 for 10 days. Poplars are a model plant with complete genomic sequence, and they are widely used in phytoremediation. Results showed poplar plants can metabolize CB3 into OH-CB3s. Three monohydroxy metabolites, including 2'-hydroxy-4-chlorobiphenyl (2'OH-CB3), 3'-hydroxy-4-chlorobiphenyl (3'OH-CB3), and 4'-hydroxy-4-chlorobiphenyl (4'OH-CB3), were identified in hydroponic solution and in different parts of the poplar plant. The metabolite 4'OH-CB3 was the major product. In addition, there were two other unknown monohydroxy metabolites of CB3 found in whole poplar plants. Based on their physical and chemical properties, they are likely to be 2-hydroxy-4-chlorobiphenyl (2OH-CB3) and 3-hydroxy-4-chlorobiphenyl (3OH-CB3). Compared to the roots and leaves, the middle portion of the plant (the middle wood and bark) had higher concentrations of 2'OH-CB3, 3'OH-CB3, and 4'OH-CB3, which suggests that these hydroxylated metabolites of CB3 are easily translocated in poplars from roots to shoots. The total masses of 2'OH-CB3, 3'OH-CB3, and 4'OH-CB3 in whole poplar plants were much higher than those in solution, strongly suggesting that it is mainly the poplar plant itself which metabolizes CB3 to OH-CB3s. Finally, the data suggest that the metabolic pathway be via epoxide intermediates.
authors.affiliation: Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, USA. zhai-guangshu@uiowa.edu
authors.forename: Guangshu
authors.initials: G
authors.lastname: Zhai
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Lehmler
authors.forename: Jerald L
authors.initials: JL
authors.lastname: Schnoor
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry*; D006900:Hydroxylation; D032107:Populus / Q000378:metabolism*
chemical_list: D001713:Biphenyl Compounds; C006983:4-chlorobiphenyl
references.citation: Chemosphere. 2008 Nov;73(10):1608-16
references.pmid: 18793792
references.citation: Chemosphere. 2001 Dec;45(8):1119-27
references.pmid: 11695625
references.citation: Chemosphere. 2009 Feb;74(7):950-61
references.pmid: 19054541
references.citation: Biochem Biophys Res Commun. 1979 Nov 28;91(2):475-83
references.pmid: 42397
references.citation: Chem Biol Interact. 2006 Feb 25;159(3):235-46
references.pmid: 16413005
references.citation: Nature. 1974 Dec 20;252(5485):698-9
references.pmid: 4215979
references.citation: Arch Biochem Biophys. 2003 Jan 1;409(1):59-71
references.pmid: 12464245
references.citation: Appl Environ Microbiol. 1999 May;65(5):2217-21
references.pmid: 10224022
references.citation: Environ Health Perspect. 2004 Aug;112(11):1208-12
references.pmid: 15289169
references.citation: Chem Res Toxicol. 1995 Jan-Feb;8(1):92-5
references.pmid: 7703372
references.citation: Crit Rev Toxicol. 1994;24(2):87-149
references.pmid: 8037844
references.citation: Sci Total Environ. 2004 Sep 20;331(1-3):125-41
references.pmid: 15325145
references.citation: Reprod Toxicol. 2005 May-Jun;20(1):57-64
references.pmid: 15808786
references.citation: Aquat Toxicol. 2006 Jun 15;78(2):176-85
references.pmid: 16621064
references.citation: Experientia. 1977 Sep 15;33(9):1134-6
references.pmid: 891850
references.citation: Chem Res Toxicol. 2004 Mar;17(3):340-7
references.pmid: 15025504
references.citation: Environ Sci Technol. 2009 Oct 1;43(19):7503-9
references.pmid: 19848168
references.citation: Environ Toxicol Pharmacol. 2008 Mar;25(2):260-6
references.pmid: 18438460
references.citation: Arch Biochem Biophys. 1995 Mar 10;317(2):464-70
references.pmid: 7893164
references.citation: Chemosphere. 2007 Oct;69(8):1221-7
references.pmid: 17640705
references.citation: Science. 1974 Aug 16;185(4151):573-82
references.pmid: 4841570
references.citation: Chem Res Toxicol. 1996 Jan-Feb;9(1):158-64
references.pmid: 8924585
references.citation: Environ Health Perspect. 2007 Jan;115(1):20-7
references.pmid: 17366814
references.citation: Environ Sci Technol. 2002 Nov 15;36(22):4735-40
references.pmid: 12487293
references.citation: Chem Res Toxicol. 2008 Jul;21(7):1359-67
references.pmid: 18549251
references.citation: Trends Biotechnol. 2003 Mar;21(3):123-30
references.pmid: 12628369
references.citation: J Bacteriol. 1995 Jan;177(1):20-6
references.pmid: 8002618
references.citation: Environ Sci Technol. 2008 Aug 1;42(15):5746-51
references.pmid: 18754503
references.citation: Xenobiotica. 1989 Nov;19(11):1307-18
references.pmid: 2515663
references.citation: Environ Sci Technol. 2006 Aug 1;40(15):4633-8
references.pmid: 16913117
references.citation: J Environ Monit. 2004 Sep;6(9):758-65
references.pmid: 15346180