Publication Date

12-2010

Advisor(s) - Committee Chair

Dr. Kinchel Doerner (Director), Dr. Rodney King, Dr. Claire Rinehart

Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

3-Methyl indole (3-MI) is a malodorant in food and animal waste and Clostridium scatologenes ATCC 25775 is the model organism for the study of 3-MI production. 3-MI is an anaerobic degradation product of L-tryptophan and can cause pulmonary disorders and death in cattle and goats. To elucidate the 3-MI biosynthesis pathway and the underlying genes, it is necessary to develop a system to allow genetic modification in Clostridium scatologenes ATCC 25775. Bacteriophages and transposons are useful tools to achieve this goal. Isolation of Clostridium scatologenes ATCC 25775 bacteriophage was attempted by prophage induction and enrichments using environmental sources. To induce prophages, cultures of Clostridium scatologenes ATCC 25775 were exposed to an effective concentration of mitomycin C at 2μg/ml and 5μg/ml. Induction with temperature was performed at 42ºC and 55ºC. Bacteriophage liberation, determined by a decrease in optical density was not observed in response to mitomycin C or by different growth temperatures. Nineteen environmental samples were tested for the presence of a bacteriophage that could infect Clostridium scatologenes ATCC 25775. The first cycle of enrichments suggested a decrease in cell density, consistent with the presence of a bacteriophage but this was not observed in further iterations. Plaque assays were performed to confirm the presence of phage, but no plaques were observed. Although, different experimental conditions were tested, a transducing bacteriophage capable of infecting Clostridium scatologenes ATCC 25775 was not isolated. Transposons have been successfully used to generate mutants in Clostridium difficle. Therefore, we attempted to introduce transposons Tn5 and Tn916 into Clostridium scatologenes ATCC 25775 using electroporation. Transposon mutagenesis using Tn916 did not yield antibiotic resistant colonies. In contrast, commercially available transposon Tn5 gave antibiotic resistant colonies. However, further screening of the colonies using transposon specific primers in PCR reactions, did not yield any PCR product. We were unsuccessful in developing a genetic modification system in Clostridium scatologenes ATCC 25775 using bacteriophage or transposons.

Disciplines

Biotechnology | Cell and Developmental Biology | Genetics | Molecular Biology