Department of Zoology, University of Maine, Orono, Maine 04473.
Plant Physiol. 1970 Nov;46(5):685-91. doi: 10.1104/pp.46.5.685.
Light induces beta-carotene synthesis in streptomycin-bleached Euglena gracilis Z. Light-adapted, chemostat-grown cells have up to 10-fold as much beta-carotene and 25% more protein than similarly grown, dark-adapted cells. Carotenogenesis does not occur under anaerobic conditions or in the presence of diphenylamine, cyanide, or cycloheximide. The blue portion of the spectrum (360-560 nm) is most active in initiating carotenogenesis. The level of cellular carotenoids is influenced by the type of carbon source and to some degree by pH. Phytofluence and zeta-carotene are present in dark-grown cells but not in cells grown aerobically in white light (360-1120 nm). These pigments, however, were present in cells grown in yellow or green light (above 486 nm) or in cells exposed to white light anaerobically. The carotenoids are localized in two types of structures at the light microscope level. A protoporphyrin was isolated from Euglena, and its role as a possible photoreceptor during carotenogenesis is suggested.
光诱导链霉素漂白的衣藻中β-胡萝卜素的合成。与同样在黑暗中生长的适应黑暗的细胞相比，适应光照的、在恒化器中生长的细胞中β-胡萝卜素的含量增加了 10 倍，蛋白质含量增加了 25%。在厌氧条件下或存在二苯胺、氰化物或环己亚胺时，不会发生类胡萝卜素的生物合成。光谱的蓝色部分（360-560nm）在启动类胡萝卜素生物合成方面最为活跃。细胞类胡萝卜素的水平受碳源的类型和一定程度上的 pH 值的影响。在黑暗中生长的细胞中存在叶黄素和ζ-胡萝卜素，但在有氧条件下在白光（360-1120nm）中生长的细胞中不存在。然而，这些色素存在于在黄光或绿光（高于 486nm）中生长的细胞或在厌氧条件下暴露于白光的细胞中。类胡萝卜素在光镜水平上定位于两种类型的结构中。从衣藻中分离出一种原卟啉，并提出其在类胡萝卜素生物合成过程中作为可能的光受体的作用。
