ANEURAL PHOTOSENSORY TRANSDUCTION IN STENTOR COERULEUS

单细胞原生动物纤毛虫，Stentor coeruleus，能够感知 光强度和波长的差异，对红色最敏感 光（610 nm）。 Stentor还可以感知光传播的方向， 它们的趋光性和负趋光性游泳证明了这一点 行为。 这种神经感光现象是由 感光体，和拟议的工作涉及如何阐明 生物体感知光信号并对其进行处理， 将光能转换为行为反应。 特别是， 我们打算研究光致质子 作为光信号的主要机制从光感受器释放 处理. 初级感觉信号，以质子释放的形式， 触发随后的转导步骤，包括钙离子从 细胞外介质。 这表明钙离子内流 导致Stentor细胞逆转其纤毛跳动， 远离光源。 本项目旨在阐明这些不同的机制， 光响应中的转导步骤及其功能网络 蓝斑大喇叭。 为此，将进一步研究光感受器蛋白。 特征，并阐明其主要的光过程 在H2O和D2O两者中进行光谱分析。 钙通道的性质 和参与纤毛逆转的Ca 2+泵也将被表征。

The unicellular protozoan ciliate, Stentor coeruleus, is able to sense differences in light intensity and wavelength, being most sensitive to red light (610 nm). Stentor also senses the direction of light propagation, as evidenced by their light-avoiding and negative phototactic swimming behaviors. This aneural photosensory phenomenon is triggered by the photoreceptor, and the proposed work involves the elucidation of how the organism perceives the light signal and processes it for subsequent sensory transduction of the light energy into behavioral responses. In particular, we propose to study the possible involvement of a light-induced proton release from the photoreceptor as a primary mechanism of light-signal processing. The primary sensory signal, in the form of proton release, triggers subsequent transduction steps that include calcium ion influx from the extracellular medium. It is proposed that the calcium ion influx causes the Stentor cell to reverse its ciliary beating and subsequently turn away from the light source. The present project is aimed at elucidating the mechanisms of these various transduction steps and their functional network in the photoresponse of Stentor coeruleus. For this aim, the photoreceptor protein will be further characterized, and its primary photoprocess will be elucidated spectroscopically in both H20 and D20. The nature of calcium channel(s) and Ca2+-pump involved in the ciliary reversal will also be characterized.