Ultraviolet-B-induced DNA damage and photorepair in the cyanobacterium Anabaena variabilis PCC 7937
Ultraviolet-B-induced DNA damage and photorepair in the cyanobacterium Anabaena variabilis PCC 7937
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DOI：
10.1016/j.envexpbot.2011.06.010
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发表时间：
2011-12-01
影响因子：
5.7
通讯作者：
Sinha, Rajeshwar P.
中科院分区：
文献类型：
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作者：
Rastogi, Rajesh P.;Singh, Shailendra P.;Sinha, Rajeshwar P.
在蓝藻鱼腥藻 PCC 7937 中研究了模拟太阳辐射对 DNA 的影响以及光再激活对 DNA 损伤效应的减轻。培养物在 295,320 和 395 nm 截止滤光片以及其他七种滤光片（例如 WG 280、WG 295、WG 305、WG 320、WG 335、WG）下进行照射345 和 GG 400。发现与 PAR 和 PAR + UV-A 辐射相比，测试生物体的生长在 UV-B 辐射下受到的影响最大。基因组 DNA 暴露于 UV-B 辐射后，16s rDNA 和 RAPD 谱的扩增受到显着影响。仅在用 UV-B 辐射（即在 295 nm 下以及在 WG 280、WG 295 和 WG 305 nm 截止滤光片下）照射的培养物中记录了 T CPD 的形成，但在 280 nm 截止滤光片下发现了最大产量。此外，随着紫外线照射时间的增加，观察到胸腺嘧啶二聚体的显着诱导。与光对照样品相比，针对 UV 诱导的 DNA 链断裂的 DNA 解旋 (FADU) 测定的荧光分析显示，在 UV-B 辐射下双链 DNA 百分比损失最大，其次是 UV-A 和 PAR。我们观察到 TT CPD 修复是光依赖性的，因为这些病变在暴露于可见光下比在黑暗中更能有效地去除。人们发现蓝色辐射比任何其他波段的光在光活化方面最有效。此外，在不同温度（10,20 和 30 摄氏度）下测量光活化速率；发现在20℃白色荧光灯下修复率最大。我们的结果表明，尽管暴露于太阳滴中存在的 UV-B 成分，但光再活化在自然条件下的生物体生存中发挥着重要作用。 (C) 2011 Elsevier B.V. 保留所有权利。
The impact of simulated solar radiation on DNA and the mitigation of DNA-damaging effects by photoreactivation was studied in a cyanobacterium Anabaena variabilis PCC 7937. Cultures were irradiated under 295,320 and 395 nm cut-off filters as well as seven other filters such as WG 280, WG 295, WG 305, WG 320, WG 335, WG 345 and GG 400. Growth of the test organism was found to be affected mostly under UV-B radiation as compared to PAR and PAR + UV-A radiations. Amplification of 16s rDNA and RAPD profile was significantly affected following exposure of genomic DNA to UV-B radiation. The formation of T CPDs was recorded only in the cultures irradiated with UV-B radiation (i.e., under 295 nm as well as under WG 280, WG 295 and WG 305 nm cut-off filters), but maximum yield was found under 280 nm cut-off filter. Furthermore, the considerable induction of thymine dimers was observed with increasing UV-irradiation times. Fluorometric analysis of DNA unwinding (FADU) assay for UV-induced DNA strand breaks exhibited the maximum loss in the percentage of dsDNA under UV-B radiation followed by UV-A and PAR in comparison to the light control samples. We observed that TT CPD repair is light-dependent, since these lesions were more efficiently removed upon exposure to visible light than in the darkness. Blue radiation was found to be the most effective in photoreactivation than any other wavebands of light. Furthermore, the rate of photoreactivation was measured under varying temperatures (10,20 and 30 degrees C); the repair rate was found to be the maximum at 20 degrees C under white fluorescent light. Our results indicate that photoreactivation play an important role in survival of the organism under natural conditions in spite of being exposed to the UV-B component present in the solar drops. (C) 2011 Elsevier B.V. All rights reserved.