Microalgae as one of the key components of food chains in aquatic environments are promising biological models for investigating gamma irradiation effects on eukaryotic organisms. Understanding resistance mechanisms in these organisms as simple models might illuminate how gamma irradiation resistance improves in these algae and even more complex organisms. The present study aimed to investigate the effects of ionizing irradiation on Chlorella vulgaris as a stress-tolerant microalga and to find how the eukaryotic cells would tolerate such stressful conditions. The physiological responses and biochemical alterations of C. vulgaris were analyzed at three different time points (0, 16, and 48 h) after 600 Gy gamma irradiation. Compared to the control, gamma-irradiated algae had slower growth rate with significantly longer lag phase, less chlorophyll and protein contents at time 0, which were compensated and recovered during the next 48 h. The results also showed spontaneous H₂O₂ burst accompanied by a higher rate of lipid peroxidation and electrolyte leakage, a rapid increase of catalase activity and more ferric reducing antioxidant power immediately after irradiation. During a 48-h period, most alterations stabilized. Raising trends were observed in the carotenoid contents, the ratios of carbohydrates, amide I and amide II to fatty acids. Principal component analysis and hierarchical clustering suggest two possible distinct mechanisms: a “quick” one including spontaneous responses by boosting H₂O₂, amplifying enzymatic antioxidant systems, and increasing compatible solutes like proline and a “delayed” responsive strategy including the increase of soluble carbohydrates, carotenoids, and stress-related proteins triggered several hours after irradiation.

微藻作为水生环境食物链的关键组成部分之一，是有前途的生物学模型，可用于研究γ射线对真核生物的影响。通过简单的模型将这些生物体的抗性机制理解为可能阐明了这些藻类甚至更复杂生物体中的伽马辐射抗性如何提高。本研究旨在研究电离辐射对小球藻作为耐胁迫微藻的影响，并寻找真核细胞如何耐受这种胁迫条件。寻常梭状芽胞杆菌的生理反应和生化变化在600 Gyγ射线照射后的三个不同时间点（0、16和48小时）进行了分析。与对照相比，γ射线辐照的藻类生长速度较慢，具有明显的滞后期，在时间0时叶绿素和蛋白质含量较低，这些在接下来的48小时内得到补偿和恢复。结果还显示自发的H ₂ O ₂爆炸后伴随着较高的脂质过氧化率和电解质渗漏，过氧化氢酶活性的快速增加以及辐照后立即具有更多的三价铁还原抗氧化能力。在48小时内，大多数变更都保持稳定。在类胡萝卜素含量，碳水化合物，酰胺I和酰胺II与脂肪酸的比率方面观察到上升趋势。主成分分析和层次聚类表明了两种可能的不同机制：一种“快速”机制，包括通过增强H ₂ O _2进行自发反应，放大酶促抗氧化剂系统，增加相容性溶质（如脯氨酸）和“延迟”响应策略，包括增加可溶性碳水化合物，类胡萝卜素和与压力有关的蛋白质在照射后数小时触发。