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|Title:||Isolation and Partial Characterization of a Pseudomonas Species That Degrades 3,6-Dichloro-2-Methoxybenzoic Acid (Analog Enrichment)|
|Author(s):||Hicks, Ronald J.|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The capacity to degrade aromatic compounds completely with even complex structures is not an unusual property of bacteria. However, chlorinated aromatic compounds tend to resist degradation. Recently, bacteria have been isolated which can utilize some chlorinated compounds as growth substrates. Bacteria capable of degrading these chlorinated compounds have been found to elaborate plasmids that encode for degradation. This present study sought to determine if a bacterium capable of utilizing 3-6-dichloro-2-methoxybenzoic acid (Dicamba) as a growth substrate could be isolated from an agricultural soil. Secondly, an assessment was made of the role of plasmid DNA in Dicamba degradation.
A Drummer silt loam soil with a previous history of herbicide usage was amended with ('14)C -Dicamba and incubated until approximately 50% of the added ('14)C was released as ('14)CO(,2). Soil samples were diluted and plated on minimal media containing Dicamba as the carbon source. The metabolic and physiological requirements of Dicamba degrading colonies arising on the plates were determined and the possible involvement of plasmids was examined.
A Pseudomonas sp. was isolated from soil that could utilize Dicamba as a growth substrate. Dicamba was toxic to the isolate at concentrations greater than 750 mg/l. Dicamba degradation was enhanced by adding the non-chlorinated analog, o-anisic acid, to the growth media. Degradation of Dicamba in soils reinoculated with the isolate increased significantly over non-inoculated controls. Finally, the results of plasmid isolation, plasmid transformation, and plasmid curing experiments suggest that plasmid DNA is not involved in Dicamba degradation.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2014-12-16|