Sinha R P, Klisch M, Helbling E W, Häder D
Institut für Botanik und Pharmazeutische Biologie, Friedrich-Alexander-Universität, Staudtstr. 5, D-91058, Erlangen, Germany.
J Photochem Photobiol B. 2001 Jul;60(2-3):129-35. doi: 10.1016/s1011-1344(01)00137-3.
Three filamentous and heterocystous N(2)-fixing cyanobacteria, Anabaena sp., Nostoc commune and Scytonema sp. were tested for the presence of ultraviolet-absorbing mycosporine-like amino acids (MAAs) and their induction by solar ultraviolet-B (UV-B) radiation. High performance liquid chromatographic (HPLC) studies revealed the presence of only one type of MAAs in all three cyanobacteria, that was identified as shinorine, a bisubstituted MAA containing both glycine and serine groups having an absorption maximum at 334 nm and a retention time of around 2.8 min. There was a circadian induction in the synthesis of MAAs when the cultures were exposed to mid-latitude solar radiation (Playa Unión, Rawson, Chubut, Patagonia, Argentina) for 3 days, 4-6th February, 2000. Solar radiation was measured by an ELDONET (European Light Dosimeter Network) filter radiometer permanently installed on the roof of the Estación de Fotobiología Playa Unión (43 degrees 18' S; 65 degrees 03' W). The maximum irradiances were around 450-500, 45-50 and 1.0-1.2 Wm(-2) for PAR (photosynthetic active radiation), UV-A (ultraviolet-A) and UV-B (ultraviolet-B), respectively. PAR and UV-A had no significant impact on MAA induction while UV-B induced the synthesis of shinorine in all three cyanobacteria. Shinorine was found to be induced mostly during the light period. During the dark period the concentration stayed almost constant. In addition to shinorine, another unidentified, water-soluble, brownish compound with an absorption maximum at 315 nm was found to be induced by UV-B only in Scytonema sp. and released into the medium. This substance was neither found in Anabaena sp. nor in Nostoc commune. Judging from the results, the studied cyanobacteria may protect themselves from deleterious short wavelength radiation by their ability to synthesize photoprotective compounds in response to UV-B radiation.
对三种丝状且具异形胞的固氮蓝细菌——鱼腥藻属（Anabaena sp.）、普通念珠藻（Nostoc commune）和席藻属（Scytonema sp.）进行了检测，以确定其是否存在吸收紫外线的类菌孢素氨基酸（MAAs）以及它们是否会被太阳紫外线-B（UV-B）辐射诱导产生。高效液相色谱（HPLC）研究表明，这三种蓝细菌中仅存在一种类型的MAAs，经鉴定为肌醇甲胺，这是一种双取代的MAAs，同时含有甘氨酸和丝氨酸基团，其最大吸收波长为334 nm，保留时间约为2.8分钟。当培养物于2000年2月4日至6日在中纬度太阳辐射（阿根廷巴塔哥尼亚丘布特省拉乌森市普拉亚联盟）下暴露3天时，MAAs的合成呈现出昼夜节律性诱导。太阳辐射由永久安装在普拉亚联盟光生物学站（南纬43度18分；西经65度03分）屋顶的ELDONET（欧洲光剂量计网络）滤光辐射计进行测量。光合有效辐射（PAR）、紫外线-A（UV-A）和紫外线-B（UV-B）的最大辐照度分别约为450 - 500、45 - 50和1.0 - 1.2 Wm(-2)。PAR和UV-A对MAAs的诱导没有显著影响，而UV-B可诱导这三种蓝细菌中肌醇甲胺的合成。肌醇甲胺大多在光照期被诱导产生。在黑暗期，其浓度几乎保持恒定。除了肌醇甲胺外，还发现了另一种未鉴定的水溶性褐色化合物，其最大吸收波长为315 nm，仅在席藻属中被UV-B诱导产生并释放到培养基中。在鱼腥藻属和普通念珠藻中均未发现该物质。从结果来看，所研究的蓝细菌可能通过响应UV-B辐射合成光保护化合物的能力来保护自身免受有害短波长辐射的伤害。
