| dc.description.abstract | CHEMISTRY
NEW METHODS TO INDUCE AND DETECT MICROBIAL SECONDARY METABOLITE PRODUCTION
C. RUTH MCNEES
Dissertation under the direction of Professor Brian O. Bachmann
Secondary metabolite production by bacteria, particularly actinomycete, has been extensively investigated, traditionally in mono-culture conditions with specific medium recipes, in an effort to identify new chemical entities with clinical relevance. Given the significant amount of research in the area of microbial secondary metabolites, the rate of discovery of unreported compounds has significantly diminished, while the increase in resistant pathogens is posing a serious medical issue. To address this issue and increase the probability of isolating new chemical entities, a multitude of new methods have been developed and more are needed. Through the application of rational alterations of the medium components and analyzing the metabolic output through statistical analysis using model actinomycetes, the development of methods for inducing secondary metabolites through the use of rare earth elements, co-culture cultivation, and low dose antibiotics have been achieved. Expanding on the evaluation of the metabolic impact of antibiotics produced by bacteria led to the development of a new method, which combines the techniques of bioautography, thin layer chromatography, and bacterial imaging mass spectrometry, to evaluate the response of an assay organism following exposure to bioactive compounds with different modes of action. The result of which was the development of a method in which detection of compounds arrayed in a 2-D fashion, as well as, the metabolic impact on the assay organism. With this method, a variety of metabolic responses, many of which showed various ion intensities for compounds with differing modes of action were detected. Further development of the method facilitated the identification of a known compound, baumycin, within a crude actinomycete extract. Purification and isolation efforts of the compound resulted in the identification of a previously unreported analogue. | |
