SYSTEM ANALYSIS OF PHYCOMYCES PHOTORESPONSES

将研究两种蓝光的光接收和感觉转导。 真菌藻类单细胞孢子囊的光响应。 趋光性和光生长反应都发生在绝对的 工作范围为10年，光照强度从10-9到10W m-2。 这一范围和相关的适应现象类似于 发生在视觉感受器细胞中。该计划的长远目标 拟议的研究是为了了解光刺激 被转化为细胞反应，特别是在具有 与黄素发色团相关的特定蓝光灵敏度。在……里面 藻霉菌，一种模式生物，遗传和生理方法可以 有效地结合在一起。向光性和光生长的作用光谱 将在不同的强度范围内测量响应，以表征 孢子囊的低强度和高强度光系统。向光性 作用光谱将通过连续光和脉冲光协议获得。 向光性的动力学实验将以时间推移的方式记录下来 视频设备，并在跟踪机的帮助下使用 新方法。结果将与光致变化性天平进行比较。 光谱来确定每个蓝光响应如何使用 光感受器系统的组成部分。最近发现的依赖 暗适应对昏暗、潜意识的光线将会有所帮助 确定哪种光感受器介导这种效应，哪种光感受器对 绿灯、红灯和蓝灯都有。系统辨识实验 光增长响应将在跟踪器上继续进行， 高斯白噪声和正弦和测试刺激以测量 这一反应的动态和非线性方面。这些实验将 涉及野生型和突变株，并将被解释为 光敏转导链动力学的解析模型。 一种新的理论，在其他地方发展，关于光分布在一个 孢子囊将通过记录方位角来进行实验测试 用水平激光照射的孢子囊周围的光图案 波束。这一理论对解释向光性作用具有重要意义。 光谱，是向光性理论的基础。最后，蜂窝 生理学方法将应用于孢子囊和原生质体。 效应物质和指示剂染料将通过直接摄取引入， 注射和电穿孔；改进的蓝光响应和效果 将在野生型和突变株的制剂中进行监测。这些 方法是针对识别分子组分和 与藻类的蓝光反应相关的途径。

Photoreception and sensory transduction will be investigated for two blue- light responses of the unicellular sporangiophore of the fungus Phycomyces. Both phototropism and the light-growth response occur over an absolute operating range of 10 decades in light intensity from 10-9 to 10 W m-2. This range and the associated adaptation phenomena are similar to those that occur in visual receptor cells. The long term objective of the proposed research is to understand the processes by which a light stimulus is transduced into a cellular response, particularly in organisms with specific blue-light sensitivity associated with flavin chromophores. In Phycomyces, a model organism, genetic and physiological approaches can be effectively combined. Action spectra for phototropism and the light-growth response will be measured in different intensity ranges to characterize the low and high intensity photosystems of the sporangiophore. Phototropism action spectra will be obtained with continuous and pulsed light protocols. Experiments on kinetics of phototropism will be recorded with time-lapse video equipment and analyzed with the aid of an tracking machine using a novel method. The results will be compared with phototropic balance spectra to determine how each of the blue-light responses uses the components of the photoreceptor system. The recently discovered dependence of dark adaptation on dim, subliminal light will be pursued to help establish which photoreceptor mediates this effect, which is sensitive to green and red as well as blue light. System-identification experiments on the light-growth response will be continued on the tracking machine with Gaussian white noise and sum-of-sinusoids test stimuli to measure the dynamic and nonlinear aspects of this response. These experiments will involve both wild-type and mutant strains, and will be interpreted with analytical models for the kinetics of the photosensory transduction chain. A new theory, developed elsewhere, concerning light distribution around a sporangiophore will be tested experimentally by recording the azimuthal light pattern around a sporangiophore illuminated with a horizontal laser beam. This theory is important for interpretation of phototropism action spectra and is fundamental for theories of phototropism. Finally, cellular physiology methods will be applied to sporangiophores and protoplasts. Effector substances and indicator dyes will be introduced by direct uptake, injection, and electroporation; modified blue-light responses and effects will be monitored in preparations from wild type and mutant strains. These approaches are directed towards identifying molecular components and pathways associated with the blue light responses of Phycomyces.