| 内容提要: |
In plants, carbon and nitrogen are directed to specific tissues or structures in accordance with developmental programs. In contrast, unicellular algae flexibly direct carbon and nitrogen to various macromolecules associated with specific intracellular compartments to optimize growth under varying environmental conditions. The signals responsible for this optimization strategy are poorly understood. They clearly are not driven by a developmental program but rather, responses to environmental cues.For example, under optimal growth conditions, ∼40% of the photosynthetically fixed carbon in typical eukaryotic microalga is directed toward the synthesis of amino acids that ultimately are incorporated into proteins. Over 50y ago, however, it was recognized that, when nitrogen limits growth, intermediate metabolism is altered, and many microalgae can accumulate storage lipids, mainly in the form of triacylglycerols (TAGs) . This phenomenon is especially pronounced in diatoms. |