ABSTRACT

The harmful effects of ultraviolet (UV) radiation have increased the demand for new sources of UV photoprotectants to develop cosmetic and skin care products. In this study, a filamentous cyanobacterial strain was isolated from the topsoil collected in an arid and exposed region in Chetimari, Niger. On the basis of 16S rDNA sequences, the isolated strain was identified as Pseudanabaena sp. CCNU1. UV-B treatment of Pseudanabaena sp. CCNU1 significantly enhanced the production of active photoprotectants, including UV-absorbing mycosporine-like amino acids (MAAs) and carotenoids. UV-B irradiation mainly induced the production of one MAA, identified as palythine-serine. The palythine-serine content was as high as 16 mg g⁻¹ dry weight after a 4-day UV-B treatment. Eight carotenoids were detected in the methanol extracts of UV-B-treated Pseudanabaena sp. CCNU1: β-carotene, echinenone, canthaxanthin, zeaxanthin, synechoxanthin, and three myxoxanthophyll derivatives. With the exception of β-carotene and echinenone, these carotenoids were positively correlated with the UV-B treatment duration. Thus, Pseudanabaena sp. CCNU1 was identified as a unique organism that produces a considerable abundance of palythine-serine as well as carotenoids to protect against UV-B radiation. Pseudanabaena sp. CCNU1 may be useful as a producer of UV photoprotectants, although the genetic basis of the relevant biosynthetic pathways remains to be precisely characterized in the future.

摘要

紫外线 (UV) 辐射的有害影响增加了对新的紫外线光保护剂来源的需求，以开发化妆品和护肤产品。在这项研究中，从尼日尔 Chetimari 干旱和暴露地区收集的表土中分离出一种丝状蓝藻菌株。根据 16S rDNA 序列，分离菌株被鉴定为Pseudanabaena sp。CCNU1. UV-B 处理Pseudanabaena sp. CCNU1 显着增强了活性光保护剂的产生，包括吸收紫外线的类菌孢素氨基酸 (MAA) 和类胡萝卜素。UV-B 照射主要诱导一种 MAA 的产生，该 MAA 被鉴定为 palythine-serine。palythine-丝氨酸含量高达16 mg g ^-14 天 UV-B 处理后的干重。在 UV-B 处理的Pseudanabaena sp.的甲醇提取物中检测到八种类胡萝卜素。CCNU1：β-胡萝卜素、海胆酮、角黄素、玉米黄质、聚虫黄质和三种粘黄素衍生物。除 β-胡萝卜素和海胆酮外，这些类胡萝卜素与 UV-B 处理持续时间呈正相关。因此，Pseudanabaena sp。CCNU1 被确定为一种独特的生物，它产生大量的 palythine-丝氨酸以及类胡萝卜素，以防止 UV-B 辐射。假单胞菌属 CCNU1 可用作紫外线光保护剂的生产者，尽管相关生物合成途径的遗传基础在未来仍有待精确表征。