CONFOCAL IMAGING OF CHANGES IN CYTOPLASMIC CA2+ IN GUARD CELLS OF ARABIDOPSIS

细胞内钙离子的升高是一个普遍存在的信号过程 在真核细胞中。生理反应的特异性 由Ca~(2+)信号启动的部分编码由 细胞内钙离子浓度升高。在植物细胞中，调节 叶片中的气体交换，对各种刺激(光， 温度、脱落酸、二氧化碳)被认为是由空间、 钙信号的时间和幅度(STA)变化。我们计划 用单个保卫细胞成像技术分析这些复杂的钙信号 利用NCMIR提供的技术。之前的研究在 施罗德博士的实验室表明，保卫细胞可以 负载钙敏感染料钙绿和富拉2 非侵入性的酯负载技术。这一重大进步可以 现在被用来研究这些细胞中的钙信号。这样的问题 作为钙离子的来源(胞外或胞内)，STA的性质 信号的频率和信号的可能振荡 地址。从NCMIR获得的图像中获得的信息 将与在 施罗德实验室利用电生理技术，如 如膜片钳和单电极电压钳。组合在一起 这些技术将产生重要的信息关于自然和 对作为产生的基础的运输过程的监管 保卫细胞内的钙信号。这项工作将使用拟南芥 守卫牢房。拟南芥突变体保卫细胞功能缺陷 都是在施罗德实验室分离出来的。这些突变体将会是 测试了它们的CA2+信号表型的变异，因此是特定的 突变可以与保卫细胞信号中的特定角色联系在一起。这个 突变工作将特别集中在激素阿西西酸(ABA)上。 ABA通过以下途径调节保卫细胞膨大，从而调节气孔开度 钙离子介导的离子通道调节。许多变种人现在 在显示异常ABA的施罗德实验室可用 回应。使用这些ABA突变体和整合 NCMIR和施罗德实验室可用的技术可以 提供关于这一作用机制的重要信息 重要的植物激素。这个项目的工作正在进行中。

The elevation of cytosolic Ca2+ is a ubiquitous signaling process in eukaryotic cells. Specificity of the physiological response initiated by the Ca2+ signal is in part encoded by the nature of the cytosolic Ca2+ increase. In plant cells, the cell pairs that regulate gaseous exchange in the leaf, specificity to various stimuli (light, temperature, abscisic acid, CO2) is thought to be encoded by spatial, temporal and amplitude (STA) variations in the Ca2+ signal. We plan to dissect these comples Ca2+ signals using single guard cell imaging utilizing the techniques available at NCMIR. Previous studies in the laboratory of Dr. J.I. Schroeder have shown that guard cells can be loaded with the Ca2+ -sensitive dyes Calcium green and Fura 2 by a non-invasive ester loading technique. This significant advance can now be utilized to study Ca2+ signals in these cells. Questions such as the source of Ca2+ (extracellular or intracellular), the STA nature of the signal and the possible oscillation of the signal will be addressed. The information obtained from the images obtained at NCMIR will be combined with concurrent experiments performed in the Schroeder laboratory that utilize electrophysiological techniques such as patch clamping and single electrode voltage clamp. The combination of these techniques will yield important information on the nature and regulation of the transport processes that underlie the generation of Ca2+ signals in guard cells. The work will use Arabidopsis thaliana guard cells. A. thaliana mutants defective in guard cell function have been isolated in the Schroeder laboratory. These mutants will be tested for variations in their CA2+ signaling phenotype, so specific mutations can be linked to defined roles in guard cell signaling. The mutant work will focus particularly on the hormone Absisic acid (ABA). ABA regulates guard cell turgor, and therefore, stomatal aperture by Ca2+-mediated regulation of ion channels. Many mutants are now available in the Schroeder laboratory which show aberrant ABA responses. Using these ABA mutants and an integration of the techniques available at NCMIR and in the Schroeder laboratory could yield important information on the mechanism of action of this important plant hormone. Work on this project is underway.