Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, Stockholm 10691, Sweden.
J Hazard Mater. 2021 Jun 5;411:124822. doi: 10.1016/j.jhazmat.2020.124822. Epub 2020 Dec 13.
Cyanobacteria, the first photoautotrophs have remarkable adaptive capabilities against most abiotic stresses, including Cd. A model cyanobacterium, Anabaena sp. PCC 7120 has been commonly used to understand cyanobacterial plasticity under different environmental stresses. However, very few studies have focused on the acute Cd toxicity. In this context, Anabaena was subjected to 100 μM Cd for 48 h (acute Cd stress, ACdS) and then transferred into the fresh medium for post-stress recovery (PSR). We further investigated the dynamics of morpho-ultrastructure, physiology, cytosolic proteome, thylakoidal complexes, chelators, and transporters after ACdS, as well as during early (ER), mid (MR), and late (LR) phases of PSR. The findings revealed that ACdS induced intracellular Cd accumulation and ROS production, altered morpho-ultrastructure, reduced photosynthetic pigments, and affected the structural organization of PSII, which subsequently hindered photosynthetic efficiency. Anabaena responded to ACdS and recovered during PSR by reprogramming the expression pattern of proteins/genes involved in cellular defense and repair; CO access, Calvin-Benson cycle, glycolysis, and pentose phosphate pathway; protein biosynthesis, folding, and degradation; regulatory functions; PSI-based cyclic electron flow; Cd chelation; and efflux. These modulations occurred in an integrated and coordinated manner that facilitated Anabaena to detoxify Cd and repair ACdS-induced cellular damage.
蓝藻是最早的光合自养生物，具有显著的适应大多数非生物胁迫的能力，包括 Cd。一种模式蓝藻，鱼腥藻 PCC 7120 常用于理解不同环境胁迫下蓝藻的可塑性。然而，很少有研究关注急性 Cd 毒性。在这种情况下，将鱼腥藻暴露于 100μM Cd 中 48 小时（急性 Cd 胁迫，ACdS），然后转移到新鲜培养基中进行胁迫后恢复（PSR）。我们进一步研究了 ACdS 后以及 ER、MR 和 LR 阶段 PSR 期间形态-超微结构、生理学、胞质蛋白质组、类囊体复合物、螯合剂和转运体的动态变化。研究结果表明，ACdS 诱导细胞内 Cd 积累和 ROS 产生，改变形态-超微结构，减少光合色素，并影响 PSII 的结构组织，从而阻碍光合作用效率。鱼腥藻通过重新编程参与细胞防御和修复的蛋白质/基因的表达模式来响应 ACdS 并在 PSR 期间恢复；CO 接入、卡尔文-本森循环、糖酵解和戊糖磷酸途径；蛋白质生物合成、折叠和降解；调节功能；PSI 为基础的循环电子流；Cd 螯合；和外排。这些调节以一种集成和协调的方式发生，使鱼腥藻能够解毒 Cd 并修复 ACdS 诱导的细胞损伤。
