Comparative Quantitative Prevalence of Mycobacteria and Functionally Abundant nidA, nahAc, and nagAc Dioxygenase Genes in Coal Tar Contaminated Sediments
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- 作者：Jennifer M. DeBruyn ; Christopher S. Chewning ; Gary S. Sayler
- 刊名：Environmental Science & Technology
- 出版年：2007
- 出版时间：August 1, 2007
- 年：2007
- 卷：41
- 期：15
- 页码：5426 - 5432
- 全文大小：307K
- 年卷期：v.41,no.15(August 1, 2007)
- ISSN：1520-5851
文摘
The Chattanooga Creek Superfund site is heavilycontaminated with metals, pesticides, and coal tar withsediments exhibiting high concentrations of polycyclicaromatic hydrocarbons (PAHs). High molecular weight PAHsare of concern because of their toxicity and recalcitrancein the environment; as such, there is great interest inmicrobes, such as fast-growing Mycobacterium spp., capableof degradation of these compounds. Real-time quantitativePCR assays were developed targeting multiple dioxygenasegenes to assess the ecology and functional diversity of PAH-degrading communities. These assays target the Mycobacterium nidA, 
-proteobacteria nagAc, and 
-proteobacterianahAc with the specific goal of testing the hypothesisthat Mycobacteria catabolic genes are enriched and maybe functionally associated with high molecular weightPAH biodegradation in Chattanooga Creek. Dioxygenasegene abundances were quantitatively compared tonaphthalene and pyrene mineralization, and temporal andspatial PAH concentrations. nidA abundances rangedfrom 5.69 × 104 to 4.92 × 106 copies per gram sediment;nagAc from 2.42 × 103 to 1.21 × 107, and nahAc from belowdetection to 4.01 × 106 copies per gram sediment. Therewas a significantly greater abundance of nidA and nagAc atsites with the greatest concentrations of PAHs. Inaddition, nidA and nagAc were significantly positivelycorrelated (r = 0.76), indicating a coexistence of organismscarrying these genes. A positive relationship was alsoobserved between nidA and nagAc and pyrene mineralizationindicating that these genes serve as biomarkers forpyrene degradation. A 16S rDNA clone library of fast-growing Mycobacteria indicated that the population is verydiverse and likely plays an important role in attenuationof high molecular weight PAHs from Chattanooga Creek.
-proteobacteria nagAc, and -proteobacterianahAc with the specific goal of testing the hypothesisthat Mycobacteria catabolic genes are enriched and maybe functionally associated with high molecular weightPAH biodegradation in Chattanooga Creek. Dioxygenasegene abundances were quantitatively compared tonaphthalene and pyrene mineralization, and temporal andspatial PAH concentrations. nidA abundances rangedfrom 5.69 × 104 to 4.92 × 106 copies per gram sediment;nagAc from 2.42 × 103 to 1.21 × 107, and nahAc from belowdetection to 4.01 × 106 copies per gram sediment. Therewas a significantly greater abundance of nidA and nagAc atsites with the greatest concentrations of PAHs. Inaddition, nidA and nagAc were significantly positivelycorrelated (r = 0.76), indicating a coexistence of organismscarrying these genes. A positive relationship was alsoobserved between nidA and nagAc and pyrene mineralizationindicating that these genes serve as biomarkers forpyrene degradation. A 16S rDNA clone library of fast-growing Mycobacteria indicated that the population is verydiverse and likely plays an important role in attenuationof high molecular weight PAHs from Chattanooga Creek.