. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 134 PHILIP B. DUNHAM AND F. M. CHILD elevated cation (shown by increase in //, cells) and large efflux of water (4-5% cell shrinkage in each case) in the first minutes. Kt per cell increases initially about times, and subsequently increases slowly to times the initial level by 200 minutes, accompanied by water re-entry. Na4 per cell increases initially to 6 times initial level, and subsequently slowly increases to times initial level at 160 minutes, with water re-entry. So equilibration in both cases
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 134 PHILIP B. DUNHAM AND F. M. CHILD elevated cation (shown by increase in //, cells) and large efflux of water (4-5% cell shrinkage in each case) in the first minutes. Kt per cell increases initially about times, and subsequently increases slowly to times the initial level by 200 minutes, accompanied by water re-entry. Na4 per cell increases initially to 6 times initial level, and subsequently slowly increases to times initial level at 160 minutes, with water re-entry. So equilibration in both cases is fast, but much faster in high Na medium. When Nat increased, final Kj per cell was not significantly different from the initial value, and likewise for Na} per cell after 200 minutes when Kj increased. This lack of reciprocal changes means that increases in KI and Nai are accompanied by proportionate increases in 100 -. 100 TIME IN MINUTES 200 FIGURE 5. Changes in cell volume and K content of Tetrahymcna after increasing KC1 concentration of normal medium. Ordinates : cell volume (open circles); K content per unit number of cells (crosses) ; K content per unit volume of cells, solid circles. Abscissa: time (minutes). KC1 concentration of normal medium was increased by 137 mM at zero time. per unit number of cells at 200 minutes was not significantly different from initial some anion, or decreases in some other cation, if electroneutrality is preserved within the cells. (In a few experiments in which both K0 and Na0 were increased, both Kj and Nai increased in the same way as when studied singly, as described.) Preliminary analyses of Cl content of cells show that Cl does not balance increases in KI or Naj. Figure 6 shows Clj values in cells in normal, dilute, and high NaCl and KC1 media. Clj is quite constant in media ranging from a 2-fold dilution (14 mM C10) up to 123 mM C10 (99 mM K0) and 73 mM C10 ( mM Na0) : for 18 determinations, Clj averaged cells, ra
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