| Summary |
The purpose of this study is to define any capacity of Staphylococcus aureus strain 7-8 to undergo photoenzymatic repair of UV-irradiation induced damage and compare it to the photoreactivation (PR) response of Escherichia coli strain B. Staphylococcus aureus showed greater inhibition by UV irradiation than E. coli. This was consistent with the higher adenine and thymine content of aureus, Staphylococcus aureus showed an enhanced rate of photoreactivation with no lag in initiation of the PR response with low PR doses compared to E. coli. Maximum PR capacity of both cultures was about equal and occurred for cultures incubated at 23-25 C. The PR responses at 11-12 and 35-37 C for aureus and coli differed, although both were capable of PR at all temperatures employed. The PR response of E. coli was directly related to the dosage of PR light (ergs/mm²); however, the photoenzymatic capacity of aureus was not directly responsive to continued decrease in light intensity. The capacity of S. aureus to undergo liquid holding recovery (LHR) occurred within a narrow range (23-25 C) , whereas E. coli underwent LHR at all but the highest temperatures (35-37 C). The LHR response of aureus was somewhat more effective than E. coli and did not show the direct response to increased liquid-holding period as coli. The PR value of a white pigmentation mutant of aureus was different from the normally pigmented parent. The relation of pigment production to photoenzymatic response of aureus requires further clarification. The PR values were non-refractoiry to exposure of cells to PR conditions in the presence of antibiotics inhibiting protein synthesis. These preliminary results may indicate the constitutive occurrence of PR enzymes. The differences observed in PR capacity and LHR response of coli and aureus to conditions of PR exposure and pigmentation were related to the natural habitats of these species. |
| General note | Submitted to the faculty of the Department of Biology. |
| General note | Advisor: Wendall E. Allen |
| Dissertation note | M.A. East Carolina University 1972 |
| Bibliography note | Includes bibliographical references (leaves 58-68). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
