Effect of osmolality on 86Rb+ uptake and release by Leishmania donovani.
Effect of osmolality on 86Rb+ uptake and release by Leishmania donovani.
复制标题
渗透压对杜氏利什曼原虫摄取和释放 86Rb 的影响。
DOI：
10.1002/jcp.1041520115
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发表时间：
1992
影响因子：
5.6
通讯作者：
Blum,JJ
中科院分区：
文献类型：
--
作者：
Blum,JJ
将杜氏利什曼原虫对数晚期培养物的前鞭毛体洗涤并重悬于不含葡萄糖或苯红但含有 20 mM (N-[2-羟乙基]哌嗪-N'-[2-乙磺酸]) (HEPES) (HBSS-, 305 mOsm/kg) 的汉克斯平衡盐溶液中。然后将它们添加到含有86 Rb的溶液中，使得最终的重量克分子渗透压浓度和离子组成符合需要。在已知时间取样并测量细胞内86 Rb的量。类似地，进行实验，其中在收集前约18小时将86 Rb添加到培养物中，并测量从洗涤的细胞中释放的86 Rb的量。在等渗条件下，900 秒内仅释放约 1.3% 的细胞内 86 Rb。如果渗透压从 305-153 mOsm/kg 降低，则该值会增加约 4 倍。这比丙氨酸响应低渗透压的快速释放要慢得多，表明丙氨酸释放不是通过非特异性孔。将温度从 26°C 降低至 3–4°C 会在等渗条件下完全抑制 86Rb 释放，并在低渗条件下很大程度上抑制 86Rb 释放。 86 Rb 释放速率对 K+ 浓度不敏感，并且如果用氨基磺酸盐代替氯化物则不会改变。哇巴因对 86 Rb 摄取或释放没有影响，但羰基氰化物 P-三氟甲氧基苯腙 (FCCP) 降低了 86 Rb 释放速率，并且在暴露约 300 秒后，完全抑制 86 Rb 摄取。阿米洛利部分抑制86Rb释放，但对摄取没有影响。 pH值从7.1降低到5.9对等渗条件下86Rb的释放影响不大，并略微增加了低渗条件下的释放速率，但降低了等渗和低渗条件下的摄取速率。取自3天稳定期培养物的细胞在等渗条件下比取自对数期晚期培养物的细胞释放86Rb更慢，但比对数期细胞对低渗应激的反应更灵敏。这些数据似乎排除了 [Na-K-Cl] 转运蛋白或 [K-Cl] 协同转运蛋白作为 K+ 释放的方式，但与 K+/H+ 交换器存在的可能性一致。还讨论了可能存在其他载体系统的可能性。 © 1992 Wiley-Liss, Inc.
Promastigotes from late‐log phase cultures ofLeishmania donovaniwere washed and resuspended in Hanks' Balanced Salt Solution without glucose or phenyl red but with 20 mM (N‐[2‐hydroxyethyl] piperazine‐N'‐[2‐ethanesulfonic acid]) (HEPES) (HBSS−, 305 mOsm/kg). They were then added to a solution containing86Rb such that the final osmolality and ionic composition was as desired. Samples were taken at known times and the amount of intracellular86Rb was measured. Similarly, experiments were performed in which86Rb was added to the cultures about 18 hr before collection, and the amount of86Rb released from the washed cells was measured. Under iso‐osmotic conditions only about 1.3% of the intracellular86Rb was released in 900 sec. This increased about 4‐fold if the osmolality was reduced from 305–153 mOsm/kg. This is much slower than the very rapid release of alanine in response to hypo‐osmotic stress, indicating that alanine release is not via a non‐specific pore. Reducing the temperature from 26°C to 3–4°C completely inhibits86Rb release under iso‐osmotic conditions and largely inhibits it under hypo‐osmotic conditions. The rate of86Rb release was not sensitive to K+concentration and was not altered if chloride was replaced by sulfamate. Ouabain had no effect on either86Rb uptake or release, but carbonylcyanide P‐trifluoromethoxyphenylhydrazone (FCCP) reduced the rate of86Rb release and, after about a 300 sec exposure, completely inhibited86Rb uptake. Amiloride partially inhibited86Rb release, but had no effect on uptake. A decrease in pH from 7.1–5.9 had little effect on86Rb release under iso‐osmotic conditions and slightly increased the rate of release under hypo‐osmotic conditions, but it decreased the rate of uptake under both iso‐osmotic and hypo‐osmotic conditions. Cells taken from 3‐day stationary phase cultures released86Rb more slowly under iso‐osmotic conditions than cells from late log phase cultures, but were more responsive to hypo‐osmotic stress than were log phase cells. These data appear to rule out an [Na‐K‐Cl] transporter or a [K‐Cl] cotransporter as the means of K+release, but are consistent with the possiblity that a K+/H+exchanger is present. The possibility that other carrier systems may be present is also discussed. © 1992 Wiley‐Liss, Inc.