The lipopolysaccharide (LPS) translocation process was studied by a pulse-chase experimental procedure designed to follow the fate of newly synthesized LPS through the cell wall fractions of the marine bacterium Alteromonas haloplanktis, strain 214, variant 3 (ATCC 19855). It was determined that newly synthesized LPS I (the prominent LPS species under the conditions employed) initially enters an LPS fraction which can be released from the cell wall along with periplasmic material. This is followed by rapid entry of the newly synthesized LPS into a loosely bound LPS fraction (released from the cell wall by washing with NaCl) before final insertion into the outer membrane. The inhibition of protein synthesis with chloramphenicol was observed to have little or no effect on the rate of translocation of newly synthesized LPS. In contrast, both the respiratory inhibitor NaCN (10 mM) and the proton ionophore 3,3',4',5-tetrachlorosalicylanilide (TCS, 30 (mu)M), if added during the chase period, resulted in an immediate and complete inhibition of further LPS translocation. The results suggest an independence of the LPS transloction process from continued protein synthesis, but a requirement for an energy source. It was observed that newly synthesized LPS sedimented to a lower density position than previously formed LPS on sucrose density gradients, and displayed a faster migration rate during electrophoresis on sodium dodecyl sulfate polyarylamide gels (SDS-PAGE). This indicated compositional differences between the two LPS populations. Extended electrophoresis on SDS-PAGE separated both newly synthesized and previously formed LPS I into a number of distinct radiolabelled peaks and shoulders, indicating compositional microheterogeneity within each species. The fate of added radiolabelled galactose was also investigated. A one minute pulse with {('14)C} galactose resulted in a preferential labelling of components associated with the cell wall such that 57.3% of the total w
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.71845 |
| Date | January 1983 |
| Creators | Bilous, Peter Thomas. |
| 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 | Doctor of Philosophy (Department of Microbiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000155568, proquestno: AAINK64582, Theses scanned by UMI/ProQuest. |
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