Pseudomonas aeruginosa grew in the presence of 10 $ mu$g/ml tetracycline (TC) or chlorotetracycline (CTC) in a minimal medium containing Mg$ sp{++}$. Growth is inhibited, with a six-fold increase in length of the lag phase. Cells revert to sensitivity when returned to antibiotic-free medium. Substitution of Mg$ sp{++}$ in the growth medium of CTC-resistant strains with Ca$ sp{++}$ and Sr$ sp{++}$ resulted in dramatic changes in growth and cell mass of cultures. Exposure of CTC-grown cells to EDTA did not result in cell lysis. SDS-PAGE of outer membrane proteins of resistant cells revealed loss of a protein band of molecular weight 73,500 D and the appearance of a 54,000 D protein band. Growth of cells resistant to CTC was hampered by subsequent exposure to penicillin G. Chelation of divalent cations from the outer membrane of sensitive cells leading to cell disruption is postulated as the primary mode of action of this antibiotic against P. aeruginosa.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.56894 |
| Date | January 1992 |
| Creators | Sergeant, Claire |
| Contributors | Ingram, Jordan M. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Microbiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001324152, proquestno: AAIMM87585, Theses scanned by UMI/ProQuest. |
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