Amino acid and potassium transport were studied in Alteromonas haloplanktis, strain 214, variant 3 (ATCC 19855). Stationary phase cells exhibited greater transport activity for AIB and K('+) than mid-logarithmic phase cells. Transport activity for amino acids in membrane vesicles was less than 1% of that in intact cells regardless of the method employed to form vesicles. French press disruption of protoplasts gave vesicle preparations with the greatest capacity for amino acid transport. Greater than 85% of the population of membrane vesicles in these preparations was oriented right-side-out as judged by freeze-etch electron microscopy. A membrane-bound, Mg('2+)-stimulated ATPase activity was present in vesicle preparations. Expression of this activity required disruption of the membrane vesicles, indicating its localisation on the inner surface of the vesicle membrane. This is further evidence that the vesicles are oriented right-side-out. K('+) transport was studied in K('+)-depleted cells by a K('+) ion-specific electrode technique. K('+) uptake was shown to be a strictly aerobic process and was concurrent with H('+) efflux. K('+) uptake occurs in response to a membrane potential and is not dependent on ATP. The membrane potential in whole cells was estimated from the K('+) distribution as -151mv. In vesicle preparations, (DELTA)(psi) was estimated by the distribution of ('3)H-TPMP('+) as -87mv. The failure of membrane vesicles to accumulate K('+) may be due to the low membrane potential that is generated in vesicle preparations.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.68517 |
| Date | January 1980 |
| Creators | Sedgwick, Edward G. |
| 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: 000593846, proquestno: AAINK50559, Theses scanned by UMI/ProQuest. |
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