Some aspects of induction mechanisms of 2, 3-dihydroxybenzoate oxygenase by Pseudomonas fluorescens / by Robert Timothy Powell.
| Author/creator | Powell, Robert Timothy author. |
| Other author | Ito, Takeru, degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 1979. |
| Description | 55 leaves, 3 unnumbered leaves of plates : illustrations ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | The soil bacterium islolated by Ayers (1978) on 2,3-DOB selective medium was identified as Pseudomonas fluoresceus. This strain grew best at room temperature (2.4-25°C) under aerated conditions. Glutamate was chosen as an alternate carbon source in the growth medium due to its lesser interference with 2,3-DOB oxygenase production by P. fluorescens. Glucose and fructose completely inhibited 2,3-DOB oxygenase induction. High enzyme induction was observed using 0.2 g 2,3-DOB per liter of glutamate growth medium. This finding resulted in a reduced 2,3-DOB expenditure. No alternate, less expensive inducers were found to elicit production of 2,3-DOB oxygenase. Among the compounds tested in this study, 2,3-DOB was the only substrate of the enzyme. The temperature optimum for 2,3-DOB oxygenase was established at 37°C and complete enzyme denaturation occurred between 50°C and 55°C. The pH optimum was near pH 8.0 with abrupt reduction in activity above that pH. A permease-mediated transport system, for 2,3-DOB in this organism. was indicated. The rate of transport was extremely rapid in starved cells. (Approximately 85% of 2,3~DOB exposed to the cells was taken up within 30 minutes.) The rate of transport was probably inhibited in growing cells by glutamate or accumulated raetabolites. Production of 2,3-DOB oxygenase began immediately after addition of 2,3-DOB to growing cultures, but in starved cells a two-hour lag period was observed between addition of 2,3-DOB and production of 2,3-DOB oxygenase. The lag period was attributed to limited availability and utilization of the "free amino acid pool" within the starved cells. The presence of phospholipids in the ultracentrifuged extract appeared to protect 2,3-DOB oxygenase activity against the effects of Bonification. However, no direct relationship between enzyme stability and membrane phospholipids could be established in this study. |
| Local note | Joyner-"Presented to the faculty of the Department of Biology ... in partial fulfillment of the requirements for the degree Master of Science in Biology." |
| General note | Presented to the Faculty of the Department of Biology. |
| General note | Advisor: Takeru Ito |
| Dissertation note | M.S. East Carolina University 1979 |
| Bibliography note | Includes bibliographical references (leaves 52-55). |
| Genre/form | dissertations. |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
| Library | Location | Call Number | Status | Item Actions |
|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
| Electronic Resources | Access Content Online | ✔ Available |