Bacteria isolated from the surface and the subsurface water at four stations along the Swedish west coast were assessed for their hydrophobicity with hydrophobic interaction chromatography (HIC). The surface bacteria were sampled by the Teflon sheet technique. [3H]-L-leucine metabolically labeled isolates were run on a column packed with Octyl-Sepharose CL-4B gel. The relative hydrophobicity of the bacteria was expressed as the ratio, g/e, between the radioactivity of the gel and the eluate. The results revealed a positive correlation between the degree of enrichment of bacteria at the surface and their hydrophobicity. The subsurface bacteria exhibited a broader spectrum of g/e-values than the surface bacteria. The initial adhesion of bacteria to the surface microlayer depends on several factors of which the hydrophobic interaction may be one of the most important.

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By using the isotope pairs 22Na-24Na and 42K-86Rb, the uptake and retention of Na and K was studied in the salt-tolerant Debaryomyces hansenii and in the less tolerant Saccharomyces cerevisiae at NaCl levels of 4 mm and 0.68, 1.35, and 2.7 M in the medium. The ratio of K to Na is much higher in the cells than in the media, and higher in D. hansenii than in S. cerevisiae under comparable conditions. The difference between the two species is due to a better Na extrusion and a better uptake of K in D. hansenii. The kinetics of ion transport show that at about the time when extrusion of Na could be demonstrated in D. hansenii, K-Rb previously lost to an easily washable compartment of the cells was reabsorbed in both organisms. More H+ was given off from S. cerevisiae than from D. hansenii in the course of these events. The findings fit the working hypothesis tested, which regards salt tolerance as partly dependent on the ability to mobilize energy to extrude Na from the cells and to take up K. The volume changes in S. cerevisiae are greater and are more slowly overcome than those in D. hansenii. The total salt level of the cells is not sufficient to counteract the osmotic potential of the medium, so that additional osmoregulatory mechanisms must be involved in determining halotoler'ance.

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