Author
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CUPPLES, ALISON - PREV. USDA POST DOC |
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Sims, Gerald |
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Submitted to: American Society for Microbiology Meeting
Publication Type: Abstract Only Publication Acceptance Date: 2/17/2006 Publication Date: 5/21/2006 Citation: Cupples, A.M., Sims, G.K. 2006. Identification of 2,4-D degrading soil microorganisms with stable isotope probing [abstract]. American Society for Microbiology. 241/Q. Interpretive Summary: Technical Abstract: Stable isotope probing (SIP) is a recently developed technique allowing function to be linked with identity without the need to isolate the bacteria involved. With this technique we investigated the microorganisms responsible for degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2, 4-D) in soil samples. Soils were unamended or amended with either unlabelled 2, 4-D or 13C6 ring-labeled 2,4-D. 2,4-D removal was complete after 17 days, whereas little removal (89 ± 3 % of applied remained) was observed in the sterile control. Terminal restriction fragment length polymorphism (TRFLP) on soil DNA after 17 days indicated a consistent increase in the relative abundance of one peak (217 bp) in soils spiked with 2, 4-D (both unlabeled and labeled samples) compared to the unamended soils. TRFLP profiles from ultracentrifugation fractions of 2, 4-D amended samples illustrated the same peak experienced an increase in buoyant density (BD) in samples spiked with 13C 2,4-D. This increase in DNA BD indicates the organism represented by peak 217 was responsible for degradation and uptake of the herbicide. Ongoing research involves identification of the microorganism represented by peak 217. Unlike traditional methods of identifying herbicide degrading bacteria, which typically involve gross manipulation of environmental samples (such as in enrichments), SIP has facilitated the identification of soil organisms degrading 2,4-D under conditions closer to the real soil environment. |
