Extracellular nucleotide effects on the electrical properties of growing Arabidopsis thaliana root hairs
Extracellular nucleotide effects on the electrical properties of growing Arabidopsis thaliana root hairs
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DOI：
10.1016/s0168-9452(99)00242-3
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发表时间：
2000-04-14
期刊：
影响因子：
5.2
通讯作者：
Dearnaley, JDW
中科院分区：
文献类型：
--
作者：
Lew, RR;Dearnaley, JDW
细胞外核苷酸使生长中的根毛的膜电位去极化。ATP和ADP （1mm）引起约100mv的去极化。其他核苷酸的相对有效性为ATP=ADP= GTP>AMP >TTP（=腺苷）> CTP。磷酸盐没有影响，表明膜电位的变化不是核苷酸水解和磷酸盐摄取的结果。更详细地表征了ATP和ADP的效应：ATP在0.4 mM处出现半最大退极化，ADP在10 μ M处出现半最大退极化；两种核苷酸处理后膜电导均未改变。后没有用。电势通常没有完全恢复，电导下降。通过葡聚糖共轭钙绿直接监测或细胞质流间接监测（不受影响），ADP浓度的增加导致去极化不影响胞浆Ca2+水平。ADP灌注后，生长略有增加（22-38%）。由于嘌呤更有效，去极化的原因可能是动物嘌呤能受体的植物同源物。ADP对膜电位作用的高特异性表明ADP可能作为细胞外信息起作用，但其潜在功能尚不清楚。它可以作为细胞损伤过程中的信号，或作为根表面附近细菌/真菌活动的传感器。(C) 2000出版的爱思唯尔科学爱尔兰有限公司。版权所有。
Extracellular nucleotides depolarize the membrane potential of growing root hairs. ATP and ADP (at 1 mM) caused depolarizations of about 100 mV. The relative effectiveness of other nucleotides was ATP=ADP= GTP>AMP >TTP (= adenosine)> CTP. Phosphate had no effect, indicating that the membrane potential changes were not a consequence of nucleotide hydrolysis and phosphate uptake. The ATP and ADP effects were characterized in more detail: half-maximal depolarization occurred at 0.4 mM for ATP, and at 10 mu M for ADP; membrane conductance was unchanged after treatment with either nucleotide. After wash-out. the potential usually did not completely recover, and conductance declined. Additions of ADP at a concentration resulting in depolarization did not affect cytosolic Ca2+ levels as monitored directly with dextran-conjugated calcium green or indirectly by cytoplasmic streaming (which was unaffected). Growth increased slightly (22-38%) after ADP perfusion. Since purines were more potent, the cause of the depolarization could be a plant homolog of an animal purinergic receptor. The surprisingly high specificity of the ADP effect on the membrane potential suggests ADP may function as an extracellular message, but its potential function is unknown. It may serve as a signal during cellular wounding, or as a sensor of bacterial/fungal activity near the root surface. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.