Role of Phosphodiesterase and G-Protein in the Response System of Phycomyces

视觉研究的主要问题之一，特别是感官系统的研究，是发现环境刺激导致感受器细胞释放动作电位(神经冲动)的机制(S)。正是这些冲动最终被大脑解释为感觉的基础。环境中的信息(例如，光能)在受体细胞中转化为神经冲动的过程称为转导。虽然真菌没有神经，因此在严格的术语解释中没有感觉系统，但一些真菌确实对光有反应。人们普遍认为，光在这些生物体中引发反应的机制与光在视觉感受器细胞中引起反应的机制相似。由于真菌在真正的视觉感受器中是不可能或极其困难的遗传和生化操作，所以阐明这些生物中的转导比在视觉感受器细胞中要容易得多。一旦真菌中的通路已知，测试视觉感受器在真菌中发生的机制就可以相当容易地完成。在这个项目中，研究人员将探索各种酶和蛋白质在真菌对光的反应中的作用，这些酶和蛋白质参与了被称为环核苷酸的化合物的新陈代谢。已经有理由怀疑这些化合物是感觉传导细胞的常见成分，而在研究中的真菌中代谢它们的一种酶是已知的对光敏感。

One of the leading problems in the study of vision, and of sensory systems in particular, is to discover the mechanism(s) by which environmental stimuli cause the receptor cells to discharge action potentials (nerve impulses). It is these impulses which are eventually interpreted by the brain as the basis for sensations. The conversion of information in the environment (for example, light energy) into nerve impulses in receptor cells is known as transduction. Although fungi do not have nerves, and therefore do not have sensory systems in the strict interpretation of the term, some fungi do respond to light. It is widely believed that the mechanism by which light elicits responses in these organisms is similar to that by which light elicits responses in visual receptor cells. Since fungi are amenable to genetic and biochemical manipulations that are impossible or extremely difficult in true visual receptors the elucidation of transduction in these organisms can be done far more easily than in visual receptor cells. Testing visual receptors for the mechanisms shown to occur in fungi can be accomplished fairly readily once the pathways are known in the fungi. In this project the investigator will explore the roles of various enzymes and proteins involved in metabolism of compounds called cyclic nucleotides in the responses of fungi to light. There are already reasons for suspecting that these compounds are common constituents of sensory transducing cells, and one of the enzymes that metabolizes them in the fungus under study is known to be sensitive to light.