Date of Defense



Biological Sciences


In these experiments, we attempted to isolate strains of Bacillus which carry antibiotic resistance genes on associated plasmids. Sodium dodecyl sulfate and mitomycin C were utilized to cure cells of plasmids, which were then assayed for loss of resistance to specific antibiotics and a concomitant lots of plasmids. A total of fifteen strains of Bacillus were studied. All of the strains but two were found to harbor plasmids and all exhibited resistance to the antibiotics tetracycline or neomycin. These organisms were able to maintain their growth in nutrient medium containing the curing agents sodium dodecy sulfate (0.001%) and mitomycin C (0.5 ug/ml). All fifteen strains were subjected to each curing agent at the appropriate concentration at 30°C for sixteen hours, and five strains were incubated at 50°C for the same time period. In each curing experiment, sensitive variants were found for each strain except for one, and the rate was doubled in the sodium dodecyl sulfate/elevated temperature experiment. Upon agarose gel electrophoresis of DNA preparations of these variants, no loss of plasmid DNA was found. Various reasons for the lack of success are discussed.

Access Setting

Honors Thesis-Campus Only