Jacques Loeb Laboratory, Hopkins Marine Station, Stanford University, California, and the Bermuda Biological Station for Research, Inc., Bermuda.
J Gen Physiol. 1938 Nov 20;22(2):255-79. doi: 10.1085/jgp.22.2.255.
The potential difference across the protoplasm of impaled cells of Halicystis is not affected by increase of oxygen tension in equilibrium with the sea water, nor with decrease down to about 1/10 its tension in the air (2 per cent O(2) in N(2)). When bubbling of 2 per cent O(2) is stopped, the P.D. drifts downward, to be restored on stirring the sea water, or rebubbling the gas. Bubbling 0.2 per cent O(2) causes the P.D. to drop to 20 mv. or less; 1.1 per cent O(2) to about 50 mv. Restoration of 2 per cent or higher O(2) causes recovery to 70 or 80 mv. often with a preliminary cusp which decreases the P.D. before it rises. Perfusion of aerated sea water through the vacuole is just as effective in restoring the P.D. as external aeration, indicating that the direction of the oxygen gradient is not significant. Low O(2) tension also inhibits the reversed, negative P.D. produced by adding NH(4)Cl to sea water, 0.2 per cent O(2) bringing this P.D. back to the same low positive values found without ammonia. Restoration of 2 per cent O(2) or air, restores this latent negativity. At slightly below the threshold for ammonia reversal, low O(2) may induce a temporary negativity when first bubbled, and a negative cusp may occur on aeration before positive P.D. is regained. This may be due to a decreased consumption of ammonia, or to intermediate pH changes. The locus of the P.D. alteration was tested by applying increased KCl concentrations to the cell exterior; the large cusps produced in aerated solutions become greatly decreased when the P.D. has fallen in 0.2 per cent O(2). This indicates that the originally high relative mobility or concentration of K(+) ion has approached that of Na(+) in the external protoplasmic surface under reduced O(2) tension. Results obtained with sulfate sea water indicate that Na(+) mobility approaches that of SO(4) (-) in 0.2 per cent O(2). P.D. measurements alone cannot tell whether this is due to an increase of the slower ion or a decrease of the faster ion. A decrease of all ionic permeability is indicated, however, by a greatly increased effective resistance to direct current during low O(2). Low resistance is regained on aeration. The resistance increase resembles that produced by weak acids, cresol, etc. Acids or other substances produced in anaerobiosis may be responsible for the alteration. Or a deficiency of some surface constituent may develop. In addition to the surface changes there may be alterations in gradients of inorganic or organic ions within the protoplasm, but there is at present no evidence on this point. The surface changes are probably sufficient to account for the phenomena.
电刺穿细胞的细胞质的潜在差异不受平衡海水中氧气张力增加的影响，也不受氧气张力降低到空气中的约 1/10（空气中 2%的氧气）的影响。当停止冒泡 2%的氧气时，PD 向下漂移，在搅拌海水或重新冒泡时恢复。冒泡 0.2%的氧气会导致 PD 下降到 20mv 或更低；1.1%的氧气约为 50mv。恢复 2%或更高的氧气会导致 PD 恢复到 70 或 80mv，通常在恢复之前有一个初步的尖峰，会降低 PD。通过向液泡中灌注充气海水与外部充气一样有效地恢复 PD，这表明氧气梯度的方向并不重要。低氧气张力也会抑制向海水中添加氯化铵产生的相反的负 PD，0.2%的氧气会将 PD 恢复到没有氨时发现的相同的低正值。恢复 2%的氧气或空气会恢复这种潜在的负性。在低于氨反转的阈值时，当第一次冒泡时，低氧气可能会引起暂时的负性，并且在恢复正 PD 之前，在充气时可能会出现负尖峰。这可能是由于氨的消耗减少，或者是由于中间 pH 值变化。通过将增加的 KCl 浓度施加到细胞外表面来测试 PD 改变的位置；在 PD 下降到 0.2%的氧气中时，在充气溶液中产生的大尖峰大大减小。这表明，在低氧气张力下，K(+)离子的原始高相对迁移率或浓度已接近外部细胞质表面的 Na(+)。用硫酸盐海水获得的结果表明，在 0.2%的氧气中，Na(+)的迁移率接近 SO(4) (-)。PD 测量本身不能说明这是由于较慢离子的增加还是较快离子的减少。然而，在低氧气时，对直流电的有效电阻大大增加表明所有离子通透性都降低。在充气时恢复低电阻。电阻增加类似于弱酸、甲酚等产生的电阻增加。厌氧产生的酸或其他物质可能是造成这种改变的原因。或者可能会出现表面某些成分的缺乏。除了表面变化之外，细胞质内无机或有机离子的梯度也可能发生变化，但目前这方面没有证据。表面变化可能足以解释这些现象。
