R. N. Singh Memorial Lab, Centre of Advanced study in Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India.
Department of Botany, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, Punjab, 144411, India.
J Phycol. 2019 Feb;55(1):60-73. doi: 10.1111/jpy.12777. Epub 2018 Sep 21.
The objective of the present study was to characterize intrinsic physiological and biochemical properties of the wall-less unicellular cholorophyte Dunaliella salina isolated from a hypersaline Sambhar Lake. The strain grew optimally at 0.5 M NaCl and 16:8 h L:D photoperiod along with maintaining low level of intracellular Na even at higher salinity, emphasizing special features of its cell membranes. It was observed that the cells experienced stress beyond 2 M NaCl as evidenced by increased intracellular reactive oxygen species and antioxidative enzymes, nevertheless proline and malondialdehyde content declined sharply accompanied by higher neutral lipid accumulation. Salinity exceeding 2 M resulted decrease in photosynthetic quantum yield (Fv/Fm) and enhanced glycerol synthesis accompanied by leakage. Super oxide dismutase seemed to play a pivotal role in antioxidative defense as eight isoforms were expressed differentially while catalase and glutathione peroxidase showing no significant change in their expression at higher salinity. The ability of D. salina to grow in range of salinities by sustaining healthy photosynthetic apparatus along with accumulation of valuable products made this alga an ideal organism that can be exploited as resource for biofuel and commercial products.
本研究的目的是描述从高盐度桑姆巴尔湖分离得到的无壁单细胞绿藻杜氏盐藻的固有生理和生化特性。该菌株在 0.5 M NaCl 和 16:8 h L:D 光周期下最佳生长，即使在较高盐度下也能维持低水平的细胞内 Na，这强调了其细胞膜的特殊特征。研究发现，当细胞经历超过 2 M NaCl 的胁迫时，细胞内活性氧和抗氧化酶的含量会增加，然而脯氨酸和丙二醛的含量会急剧下降，同时中性脂质的积累会增加。当盐度超过 2 M 时，光合量子产量（Fv/Fm）会下降，甘油合成会增加，同时伴随着泄漏。超氧化物歧化酶似乎在抗氧化防御中发挥着关键作用，因为 8 种同工酶的表达存在差异，而过氧化氢酶和谷胱甘肽过氧化物酶在高盐度下的表达没有明显变化。杜氏盐藻能够在一定盐度范围内生长，维持健康的光合作用装置，并积累有价值的产物，这使得这种藻类成为一种理想的生物，可以被开发为生物燃料和商业产品的资源。
