Adaptation of Cyanobacteria to High Solar Irradiance: UV-Shielding Compounds

许多蓝藻(蓝藻)在它们细胞周围的鞘中产生一种淡黄色的色素。我们已经证明，这种色素是一种有效的防晒霜，可以保护生物体免受紫外线(UV)辐射的破坏。这一保护系统是在地球生命的早期阶段(即前寒武纪)进化出来的，当时紫外线辐射较高。在接下来的三年里，我们将继续努力了解这种色素的化学性质，生产过程中的生化步骤，它的数量是如何调节的，以及它在多大程度上可以与细胞内的其他紫外线吸收物质(即霉菌孢子素)协调工作。我们将在实验中确定这些类似霉孢素的化合物与那些没有作用的化合物的重要性，并事实上试图确定那些缺乏防晒霜的物种在高紫外线辐射下生存的其他方法。当平流层臭氧消耗威胁增加地球表面紫外线的破坏性水平时，这项研究尤其相关。

Many cyanobacteria (blue-green algae) produce a yellowish pigment in the sheaths surrounding their cells. We have shown that the pigment (scytonemin) is an effective sunscreen, shielding the organism from the damaging effects of ultra-violet (UV) radiation. It is that this protective system evolved during the early periods of life on earth (i.e. the Precambrian) when UV radiation was higher. Over the next three years we will continue to try understand the chemical nature of this pigment, the biochemical steps in its production, how its quantity is regulated, and to what extent it may work in harmony with other UV-absorbing substances within the cells (i.e. mycosporines). We will experimentally determine the importance of these mycosporine-like compounds with those that do not, and in fact try to determine what other means are used to survive under high UV radiation by those species lacking sunscreens. This research is particularly relevant now when stratospheric ozone depletion is threatening to increase damaging levels of UV at the earth's surface.