K+ transport in the caterpillar intestine epithelium: role of osmolytes for the K+-secretory capacity of the tobacco hornworm midgut
K+ transport in the caterpillar intestine epithelium: role of osmolytes for the K+-secretory capacity of the tobacco hornworm midgut
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毛毛虫肠上皮中的钾转运：渗透剂对烟草天蛾中肠钾分泌能力的作用
DOI：
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
W. Zeiske
中科院分区：
文献类型：
--
作者：
Heiko Meyer;H. Wieczorek;W. Zeiske
烟草角虫（Manduca sexta）的中肠积极分泌钾离子。这可以用短路电流（Isc）来测量，将中肠安装在Ussing腔中，并与含166 mM蔗糖的高k +盐水混合。非代谢化合物（甘露醇、尿素、NaCl和聚乙二醇200、400和600）对蔗糖的等渗透取代导致了电流的急剧下降，尽管这是可逆的。阿卡波糖是脊椎动物和昆虫的一种特异性蔗糖酶抑制剂，对Isc没有可检测到的影响。出乎意料的是，在用葡萄糖、果糖、海藻糖或棉子糖等糖代替蔗糖后，K+电流不再得到支持。然而，所有比蔗糖小的渗透物（NaCl除外），无论是否可代谢，都引起Isc立即、相当均匀但短暂地增加约20%，然后最终下降到远低于控制值的水平。省略蔗糖的低渗透处理也会瞬间增加K+电流。当上皮在低渗透压状态下受到冲击时，小渗透液代替蔗糖不会引起短暂的Isc刺激；但是，无法阻止Isc的最终下降。我们的数据似乎与蔗糖作为能量剂或简单渗透剂的作用不一致。相反，我们在此讨论其可能的作用，类似于蔗糖在低等真核生物或植物中的作用，作为细胞外和/或细胞内的“相容渗透物”，稳定与K+运输有关的蛋白质的结构和/或功能。
The midgut of the tobacco hornworm, Manduca sexta, actively secretes potassium ions. This can be measured as short-circuit current (Isc) with the midgut mounted in an Ussing chamber and superfused with a high-K+ saline containing as its major osmolyte 166 mM sucrose. Iso-osmotic substitution of sucrose by non-metabolisable compounds (mannitol, urea, NaCl and the polyethylene glycols 200, 400 and 600) led to a dramatic, though reversible, drop in the current. Acarbose, a specific inhibitor of invertase (sucrase) in vertebrates and insects, had no detectable influence on Isc. Unexpectedly, after replacing sucrose iso-osmotically with the saccharides glucose, fructose, trehalose or raffinose, the K+ current could no longer be supported. However, all osmolytes smaller than sucrose (except for NaCl), metabolisable or not, initiated an immediate, quite uniform but transient, increase in Isc by about 20%, before its eventual decline far below the control value. Hypo-osmotic treatment by omission of sucrose also transiently increased the K+ current. Small osmolytes substituted for sucrose caused no transient Isc stimulation when the epithelium had been challenged before with hypo-osmolarity; however, the eventual decline in Isc could not be prevented. Our data seem inconsistent with a role of sucrose as energiser or simple osmolyte. Rather, we discuss here its possible role as analogous to that of sucrose in lower eukaryotes or plants, as an extra- and/or intracellular “compatible osmolyte” that stabilises structure and/or function of the proteins implicated in K+ transport.
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DOI：
10.1073/pnas.95.16.9268
发表时间：
1998-08-04
影响因子：
11.1
作者：
Qu, YX;Bolen, CL;Bolen, DW
通讯作者：
Bolen, DW
DOI：
10.1146/annurev.physiol.60.1.719
发表时间：
1998
期刊：
Annual review of physiology.
影响因子：
--
作者：
Kirk,K;Strange,K
通讯作者：
Strange,K
DOI：
--
发表时间：
2002-04
期刊：
The Journal of experimental biology
影响因子：
--
作者：
S. Reineke;H. Wieczorek;H. Merzendorfer
通讯作者：
S. Reineke;H. Wieczorek;H. Merzendorfer
影响因子：
4.2
作者：
USHIJIMA, K;RIBY, JE;KRETCHMER, N
通讯作者：
KRETCHMER, N
鳞翅目中肠的隔离、电压钳位和通量测量。
影响因子：
--
作者：
Harvey,WR;Crawford,DN;Spaeth,DD
通讯作者：
Spaeth,DD