Despite being an autotrophic organism, Galdieria phlegrea (Galdieriaceae) has the ability to use glycerol thereby switching to heterotrophy in the dark and mixotrophy in the presence of light. To examine cellular changes during the switch to mixotrophic metabolism and finally to photoautotrophic metabolism, heterotrophic cells of G. phlegrea were exposed to light and split into two subcultures. Cells exposed only to light but cultivated in medium containing glycerol grew with a recovery time of at least 3 days. In a parallel culture, the simultaneous removal of glycerol from the culture medium and light exposure allowed Galdieria cells to rapidly recover their growth rate due to their ability to rapidly absorb ammonium from the medium. However, contrary to expectation, a higher content of total soluble protein was observed in light-exposed cells cultivated in medium containing glycerol compared to cells cultivated without glycerol. In addition, the level of Rubisco in cells exposed to light and cultivated without glycerol was higher than those in cells cultivated in medium containing glycerol, indicating full photosynthetic functionality after only 3 days of light treatment. The greater chlorophyll a content confirms that the photosynthetic activity of cells cultivated without glycerol recovers earlier than that of heterotrophic cells exposed to light but still cultivated in medium containing glycerol.

中文翻译：

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Galdieria phlegrea 的异养培养在存在或不存在甘油的情况下转变为自养

尽管是自养生物，Galdieria phlegrea (Galdieriaceae) 具有使用甘油的能力，从而在黑暗中转换为异养，在光照下转换为混合营养。为了检查在转换为混合营养代谢并最终转换为光合自养代谢期间的细胞变化，将 G. phlegrea 的异养细胞暴露在光下并分成两个亚培养物。仅暴露于光但在含有甘油的培养基中培养的细胞的生长恢复时间至少为 3 天。在平行培养中，同时从培养基中去除甘油和光照使 Galdieria 细胞能够快速恢复其生长速度，因为它们能够从培养基中快速吸收铵。然而，出乎意料的是，与不含甘油培养的细胞相比，在含有甘油的培养基中培养的暴露于光的细胞中观察到更高含量的总可溶性蛋白质。此外，暴露于光且不加甘油培养的细胞中 Rubisco 的水平高于在含甘油培养基中培养的细胞，表明仅经过 3 天的光照处理即可实现完全的光合功能。较高的叶绿素 a 含量证实，在没有甘油的情况下培养的细胞的光合活性比暴露于光但仍在含有甘油的培养基中培养的异养细胞恢复得更早。暴露于光且不含甘油培养的细胞中 Rubisco 的水平高于在含有甘油的培养基中培养的细胞中的 Rubisco 水平，表明仅经过 3 天的光照处理就具有完全的光合功能。较高的叶绿素 a 含量证实，在没有甘油的情况下培养的细胞的光合活性比暴露于光但仍在含有甘油的培养基中培养的异养细胞恢复得更早。暴露于光且不含甘油培养的细胞中 Rubisco 的水平高于在含有甘油的培养基中培养的细胞中的 Rubisco 水平，表明仅经过 3 天的光照处理就具有完全的光合功能。较高的叶绿素 a 含量证实，在没有甘油的情况下培养的细胞的光合活性比暴露于光但仍在含有甘油的培养基中培养的异养细胞恢复得更早。