title: Bacterial acquisition of hexachlorobenzene-derived carbon in contaminated soil.
abstract: Pesticides are a class of xenobiotics intentionally released into the environment. Hexachlorobenzene (HCB) was used as a fungicide from 1945, leaving behind many contaminated sites. Very few studies have examined the biodegradation of HCB or the fate of HCB-derived carbon. Here we report that certain bacterial populations are capable of deriving carbon from HCB in contaminated soil under aerobic conditions. These populations are primarily Proteobacteria, including Methylobacterium and Pseudomonas, which predominated as detected by stable isotope probing (SIP) and 16S rRNA gene amplicon pyrosequencing. Due to the nature of SIP, which can be used as a functional method solely for assimilatory processes, it is not possible to elucidate whether these populations metabolized directly HCB or intermediates of its metabolism produced by different populations. The possibility exists that HCB is degraded via the formation of pentachlorophenol (PCP), which is further mineralized. With this in mind, we designed primers to amplify PCP 4-monooxygenase-coding sequences based on the available pcpB gene sequence from Methylobacterium radiotolerans JCM 2831. Based on 16S rRNA gene analysis, organisms closely related to this strain were detected in (13)C-labeled DNA. Using the designed primers, we were able to amplify pcpB genes in both total community DNA and (13)C-DNA. This indicates that HCB might be transformed into PCP before it gets assimilated. In summary, this study is the first report on which bacterial populations benefit from carbon originating in the pesticide HCB in a contaminated soil.
authors: Institute of Chemical Technology Prague, Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, Technicka 3, 166 28 Prague 6, Czech Republic. Electronic address: ondrej.uhlik@vscht.cz.
authors: Ondrej
authors: O
authors: Uhlik
authors: Institute of Chemical Technology Prague, Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, Technicka 3, 166 28 Prague 6, Czech Republic.
authors: Michal
authors: M
authors: Strejcek
authors: Institute of Chemical Technology Prague, Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, Technicka 3, 166 28 Prague 6, Czech Republic.
authors: Jan
authors: J
authors: Vondracek
authors: Institute of Chemical Technology Prague, Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, Technicka 3, 166 28 Prague 6, Czech Republic.
authors: Lucie
authors: L
authors: Musilova
authors: Institute of Molecular Genetics, Czech Academy of Sciences, Department of Genomics and Bioinformatics, Videnska 1083, 142 20 Prague 4, Czech Republic.
authors: Jakub
authors: J
authors: Ridl
authors: Institute of Chemical Technology Prague, Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, Technicka 3, 166 28 Prague 6, Czech Republic.
authors: Petra
authors: P
authors: Lovecka
authors: Institute of Chemical Technology Prague, Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, Technicka 3, 166 28 Prague 6, Czech Republic. Electronic address: tomas.macek@vscht.cz.
authors: Tomas
authors: T
authors: Macek
mesh_terms: D001673:Biodegradation, Environmental; D002247:Carbon Isotopes / Q000378:metabolism; D018153:Czech Republic; D017931:DNA Primers; D006581:Hexachlorobenzene / Q000737:chemistry / Q000378:metabolism*; D007553:Isotope Labeling; D020580:Methylobacterium / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism; D015394:Molecular Structure; D010416:Pentachlorophenol / Q000737:chemistry / Q000378:metabolism; D011549:Pseudomonas / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D017931:DNA Primers; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D006581:Hexachlorobenzene; D010416:Pentachlorophenol; D006899:Mixed Function Oxygenases; C069781:pentachlorophenol monooxygenase
keywords: 16S rRNA genes; Amplicon pyrosequencing; Bioremediation; Pentachlorophenol 4-monooxygenase; Pesticides; Stable isotope probing