Regulation of Calcium Transport in Barley Aleurone Cells

拟议研究的目标是实现一个 大麦糊粉层细胞钙稳态的理解。 实验室先前的研究是合成钙- 含有金属酶，α-淀粉酶，已经确定， 细胞质钙浓度维持在狭窄范围内， 限制，而钙的恒定通量发生通过 细胞质 实验提出了确定的来源， 确保细胞质钙稳态的钙。 贴片 钳位技术将被用来识别通道中的 糊粉细胞的质膜和液泡膜， 进入细胞质的离子流。 实验方法 依赖于分离功能性原生质体的能力， 糊粉层，并使用这些原生质体作为完整的来源 空泡 细胞膜通道活性的变化 糊粉原生质体和从原生质体分离的液泡中 已经在这个实验室里测量过了;因此， 方法应该成功。 在种子萌发过程中， 贮藏器官如糊粉层被调动起来， 生长中的植物胚胎 虽然这些储备是 至关重要的是，人们对这些物质是如何被调动起来的知之甚少。 据认为，赤霉酸参与，但机制 其作用是什么，我们不得而知。 这个实验室已经证明， 钙的动员对于 赤霉酸诱导的α-淀粉酶的合成， 在糊粉层细胞中运输贮藏物质方面起重要作用。 该项目旨在了解钙是如何 在大麦糊粉层细胞中受到调控。 结果应该说明 调节代谢物动员的重要步骤 在种子萌发期间。

The goals of the proposed research are to achieve an understanding of calcium homeostasis in the barley aleurone cell. Prior work from this laboratory on the synthesis of the calcium- containing metalloenzyme, alpha-amylase, has established that the cytoplasmic calcium concentration is maintained within narrow limits while a constant flux of calcum occurs through the cytoplasm. Experiments are proposed to determine the source of the calcium that assures cytoplasmic calcium homeostasis. Patch clamp techniques will be used to identify the channels in the plasm membrane and tonoplast of the aleurone cell that regulate the flux of ions into the cytoplasm. The experimental approach relies on the ability to isolate functional protoplasts from the aleurone layer and to use these protoplasts as a source of intact vacuoles. The activties of channels in the plasma membrane of aleurone protoplasts and in vacuoles isolated from protoplasts have already been measured in this laboratory; thus, this approach should succeed. During seed germination metabolites stored in the vacuoles of storage organs such as aleurone layers are mobilized for use by the growing plant embryo. Although these stored reserves are crucial, little is known about how these materials are mobilized. It is thought that giberellic acid is involved, but the mechanism by which it acts is not known. This laboratory has shown that mobilization of calcium is of central importance to the giberellic acid-induced synthesis of alpha-amylase, an enzyme important in mobilizing storage products in the aleurone cell. This project is directed toward understanding how calcium is regulated in barley aleurone cells. The results should elucidate an important step in the regulation of metabolite mobilization during seed germination.