Dubey Shubham Kumar, Lee Seung Sik, Kim Jin-Hong
Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu-gil, Jeongeup-si, Jeonbuk-do, 56212, Republic of Korea.
Department of Radiation Science, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea.
Biotechnol Biofuels Bioprod. 2024 Oct 1;17(1):125. doi: 10.1186/s13068-024-02575-5.
Ionizing radiation has been used for mutagenesis or material modification. The potential to use microalgae as a platform for antimicrobial production has been reported, but little work has been done to advance it beyond characterization to biotechnology. This study explored two different applications of ionizing radiation as a metabolic remodeler and a molecular modifier to enhance the antimicrobial activity of total protein and solvent extracts of Chlamydomonas reinhardtii cells.
First, highly efficient transgenic C. reinhardtii strains expressing the plant-derived antimicrobial peptides, AtPR1 or AtTHI2.1, were developed using the radiation-inducible promoter, CrRPA70Ap. Low transgene expression was significantly improved through X-irradiation (12-50 Gy), with peak activity observed within 2 h. Protein extracts from these strains after X-irradiation showed enhanced antimicrobial activity against the prokaryotic bacterium, Pseudomonas syringae, and the eukaryotic fungus, Cryptococcus neoformans. In addition, X-irradiation (12 Gy) increased the growth and biomass of the transgenic strains. Second, C. reinhardtii cell extracts in ethanol were γ-irradiated (5-20 kGy), leading to molecular modifications and increased antimicrobial activity against the phytopathogenic bacteria, P. syringae and Burkholderia glumae, in a dose-dependent manner. These changes were associated with alterations in fatty acid composition. When both transgenic expression of antimicrobial peptides and molecular modification of bioactive substances were applied, the antimicrobial activity of C. reinhardtii cell extracts was further enhanced to some extent.
Overall, these findings suggest that ionizing radiation can significantly enhance the antimicrobial potential of C. reinhardtii through efficient transgene expression and molecular modification of bioactive substances, making it a valuable source of natural antimicrobial agents. Ionizing radiation can act not only as a metabolic remodeler of transgene expression in microalgae but also as a molecular modifier of the bioactive substances.
电离辐射已被用于诱变或材料改性。已有报道称微藻有潜力作为抗菌剂生产的平台，但在将其从特性研究推进到生物技术应用方面所做的工作很少。本研究探索了电离辐射作为代谢重塑剂和分子改性剂的两种不同应用，以增强莱茵衣藻细胞总蛋白和溶剂提取物的抗菌活性。
首先，利用辐射诱导型启动子CrRPA70Ap开发了高效表达植物源抗菌肽AtPR1或AtTHI2.1的转基因莱茵衣藻菌株。通过X射线照射（12 - 50 Gy）显著提高了低水平的转基因表达，在2小时内观察到峰值活性。这些菌株经X射线照射后的蛋白提取物对原核细菌丁香假单胞菌和真核真菌新生隐球菌显示出增强的抗菌活性。此外，X射线照射（12 Gy）增加了转基因菌株的生长和生物量。其次，对乙醇中的莱茵衣藻细胞提取物进行γ射线照射（5 - 20 kGy），导致分子修饰，并以剂量依赖的方式增加了对植物病原菌丁香假单胞菌和谷壳伯克霍尔德菌的抗菌活性。这些变化与脂肪酸组成的改变有关。当同时应用抗菌肽的转基因表达和生物活性物质的分子修饰时，莱茵衣藻细胞提取物的抗菌活性在一定程度上进一步增强。
总体而言，这些发现表明电离辐射可通过高效的转基因表达和生物活性物质的分子修饰显著增强莱茵衣藻的抗菌潜力，使其成为天然抗菌剂的宝贵来源。电离辐射不仅可以作为微藻中转基因表达的代谢重塑剂，还可以作为生物活性物质的分子改性剂。
