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Recently much information has accumulated indicating specific functions of inorganic ions, especially Na⁺ in the nutrition and metabolism of marine bacteria. A number of marine bacteria have been reported to have a specifie Na+ requirement for growth and for optimal metabolism. The function of the ions has been considered to be more than a simple osmotic effect, since evidence has been obtained, indicating that inorganic ions play a major part in the maintenance of the integrity of the cell wall. It has also been shown, recently, that Na⁺ is involved in the penetration of substrates into cells of marine bacteria. Since marine bacteria appear to have special requirements for inorganic ions for growth, transport and the maintenance of cell wall integrity, the knowledge of intracellular ion concentrations are of particular importance to an understanding of the relation of marine bacterial cells to their environment. Only one marine bacterium has so far been examined in any detail in this connection. The aim of this investigation has been to study ion distributions and the conditions affecting ion uptake in three other marine bacterial species. In this study the actual intracellular Na⁺, K⁺ and Cl⁻ concentrations have been determined directly and the penetration and the exchange of Na²² isotope into the cells has been measured. [...]

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.

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Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Oceanography." Includes bibliographical references (p. 142-146).

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1989. / Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 102-112).

Thesis (M.S.) in Microbiology--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 39-45).

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