Volgusheva A A, Zagidullin V E, Antal T K, Korvatovsky B N, Krendeleva T E, Paschenko V Z, Rubin A B
Biological Faculty, Moscow State University, Vorobyevi Gory 119992, Moscow, Russia.
Biochim Biophys Acta. 2007 Jun;1767(6):559-64. doi: 10.1016/j.bbabio.2007.04.006. Epub 2007 May 3.
Chlorophyll fluorescence decay kinetics was measured in sulfur deprived cells of green alga Chlamydomonas reinhardtii with a home made picosecond fluorescence laser spectrometer. The measurements were carried out on samples either shortly adapted to the dark ('Fo conditions') or treated to reduce Qa ('Fm conditions'). Bi-exponential fitting of decay kinetics was applied to distinguish two components one of them related to energy trapping (fast component) and the other to charge stabilization and recombination in PS 2 reaction centers (slow component). It was found that the slow component yield increased by 2.0 and 1.2 times when measured under 'Fo' and 'Fm conditions', respectively, in sulfur deprived cells as compared to control ones. An additional rapid rise of the slow component yield was observed when incubation was carried out in a sealed bioreactor and cell culture turned to anaerobic conditions. The obtained results strongly indicate the existence of the redox control of PS 2 activity during multiphase adaptation of C. reinhardtii to sulfur deficiency stress. Probable mechanisms responsible for the observed increased recombinant fluorescence yield in starved cells are discussed.
利用自制的皮秒荧光激光光谱仪，测定了莱茵衣藻硫缺乏细胞中的叶绿素荧光衰减动力学。测量在短期适应黑暗的样品（“Fo条件”）或经过处理以降低Qa的样品（“Fm条件”）上进行。对衰减动力学进行双指数拟合，以区分两个成分，其中一个与能量捕获有关（快速成分），另一个与PS 2反应中心的电荷稳定和复合有关（慢速成分）。结果发现，与对照细胞相比，硫缺乏细胞在“Fo”和“Fm条件”下测量时，慢速成分产率分别增加了2.0倍和1.2倍。当在密封生物反应器中进行培养且细胞培养变为厌氧条件时，观察到慢速成分产率出现额外的快速上升。所得结果有力地表明，在莱茵衣藻对硫缺乏胁迫的多阶段适应过程中存在PS 2活性的氧化还原控制。讨论了饥饿细胞中观察到的重组荧光产率增加的可能机制。
