Lee Tzan-Chain, Hsu Ban-Dar
Department of Life Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan.
Protoplasma. 2014 Sep;251(5):1201-11. doi: 10.1007/s00709-014-0627-y. Epub 2014 Mar 6.
To find out how microalgae cope with heat stress, the small vegetative cells of a synchronous Scenedesmus vacuolatus culture were subjected to heat treatment and then cultured under continuous illumination. The heat-treated cells were found first to enter a degenerative intermediate stage with low cellular activities almost right after the start of the cultivation, which was then followed by a revival. The changes in physiological activities and morphology of the treated cells throughout the whole period of regeneration were explored. The variations in cellular DNA content and protein composition were also investigated. Stressed cells at the end of the degeneration stage were completely bleached and were also characterized by condensed but undegraded chromatin, partially disintegrated chloroplasts but with the thylakoid membrane system retained, partially operating mitochondria, intact plasma membranes, and a dramatically changed profile of cellular proteins. All of our data indicate they were still alive but in a different physiological state than the control cells. Recovery started with regeneration of mitochondrial cristae and redispersion of chromatins. These were followed by regreening and resuscitation of chloroplasts, which often started from one part of a thylakoid membrane system and then spread out. This study provided a unicellular model for studying how plant cells react to a period of stress and recover.
为了弄清楚微藻如何应对热应激，对同步培养的空星藻营养小细胞进行热处理，然后在连续光照下培养。发现热处理后的细胞在培养开始后几乎立即进入细胞活性较低的退化中间阶段，随后是复苏阶段。研究了处理后细胞在整个再生过程中的生理活动和形态变化。还研究了细胞DNA含量和蛋白质组成的变化。退化阶段末期的应激细胞完全变白，其特征还包括染色质浓缩但未降解、叶绿体部分解体但类囊体膜系统保留、线粒体部分功能正常、质膜完整以及细胞蛋白质谱显著改变。我们所有的数据表明它们仍然存活，但处于与对照细胞不同的生理状态。恢复始于线粒体嵴的再生和染色质的重新分散。随后是叶绿体的重新变绿和复苏，叶绿体的重新变绿和复苏通常从类囊体膜系统的一部分开始，然后扩散开来。这项研究为研究植物细胞如何应对一段时间的应激并恢复提供了一个单细胞模型。
