Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India.
J Photochem Photobiol B. 2013 Jul 5;124:63-70. doi: 10.1016/j.jphotobiol.2013.04.007. Epub 2013 Apr 25.
In this study, we evaluated the inhibitory effect of NaCl on cell growth, photochemistry and protein profile of photosystem (PS) II in Chlamydomonas reinhardtii. To study the effect of NaCl on the photosynthetic apparatus, the C. reinhardtii cells were grown at different concentrations (0, 50, 100 and 150 mM). NaCl induced flagellar resorption due to which the cells lost their motility, formation of palmelloids, reduced cell size and slower cell division. Chlorophyll fluorescence transients at different NaCl concentrations had decreased intensities of all peaks (OJIP) indicating the apparent inactivation energies of both donor and acceptor side of PSII. Consequently, inhibition of electron transport occurred particularly at PSII. Further, low temperature emission spectra showed that the rate of damage to the PSII was more when compared to PSI. Also, we have carried out the visible circular dichroism spectra from thylakoids where the major peaks contributed to chlorophyll a and b are equally reduced in different salt grown cells, which may explain the changes at the level of inter pigment-pigment interactions. Furthermore protein profile analysis of PSII revealed that the major subunit of light harvesting complex (LHC)II is more prone to salt stress than core proteins of PSII indicating the light harvesting funnel from LHCII to PSII core is impaired.
在这项研究中，我们评估了 NaCl 对莱茵衣藻细胞生长、光化学和光系统 II（PS II）蛋白谱的抑制作用。为了研究 NaCl 对光合作用器的影响，将莱茵衣藻细胞在不同浓度（0、50、100 和 150 mM）下生长。NaCl 诱导鞭毛收缩，导致细胞失去运动性、形成类囊体、细胞体积减小和细胞分裂速度减慢。不同 NaCl 浓度下的叶绿素荧光瞬变降低了所有峰（OJIP）的强度，表明 PS II 的供体和受体侧的明显失活能。因此，电子传递的抑制特别发生在 PS II 上。此外，低温发射光谱表明，与 PSI 相比，PS II 的损伤速度更快。此外，我们还从类囊体中进行了可见圆二色性光谱，其中主要峰归因于叶绿素 a 和 b，在不同盐生长的细胞中均有同等程度的减少，这可以解释色素间相互作用水平的变化。此外，PS II 的蛋白谱分析表明，光捕获复合物（LHC）II 的主要亚基比 PS II 的核心蛋白更容易受到盐胁迫的影响，这表明从 LHC II 到 PS II 核心的光捕获漏斗受损。
