Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Jochanan Stenesh

Second Advisor

Dr. Robert Harmon

Third Advisor

Dr. J. Lindsley Foote

Access Setting

Masters Thesis-Open Access


Survival curves were determined for the mesophile, Bacillus licheniformis and the thermophile, Bacillus stearothermophilus after subjecting the cells to ultraviolet irradiation. Cells were grown at 37°C for the mesophile and at 55°C for the thermophile.

At low UV exposure times, the thermophile was more resistant to UV irradiation (had a better survival rate) than was the case for the mesophile. At higher exposure times, the situation was reversed, the mesophile having a greater survival rate than the thermophile.

The effect of changes in the temperature during irradiation was also determined. Thermophiles were greatly affected by changes in temperature while the mesophile appeared to be relatively insensitive to variations in temperature (except at a 50 second exposure time).

Varying the incubation temperature at which irradiated cells were allowed to grow led to significant changes in the survival curves of the thermophiles. The survival rate was greater when the cells were incubated at 63°C, as compared to their incubation at 55°C. However, changes in the incubation temperature had little or no effect on the survival curves of the mesophile.