Dillon Jesse G, Tatsumi Cecelia M, Tandingan Patrick G, Castenholz Richard W
Department of Biology, University of Oregon, Eugene, 97403, USA.
Arch Microbiol. 2002 Apr;177(4):322-31. doi: 10.1007/s00203-001-0395-x. Epub 2002 Jan 31.
Abstract. The UV-screening pigment scytonemin is found in many species of ensheathed cyanobacteria. Past work has shown that the pigment is synthesized in response to exposure to UV-A irradiance. This study investigated the effect of other correlated stress factors including heat, osmotic and oxidative stress on the synthesis of scytonemin in a clonal cyanobacterial isolate ( Chroococcidiopsis sp.) from an epilithic desert crust. Stress experiments were carried out both in conjunction with UV-A irradiance and in isolation. Increases in both temperature and photooxidative conditions in conjunction with UV-A caused a synergistic increase in the rate of scytonemin production. In contrast, increased salt concentration under UV-A irradiance inhibited scytonemin synthesis. However, unlike the responses to temperature and oxidative stress, cells synthesized low levels of scytonemin under osmotic stress in the absence of scytonemin-inducing irradiance. These results suggest that scytonemin induction may be regulated as a part of a complex stress response pathway in which multiple environmental signals affect its synthesis.
摘要。紫外线屏蔽色素鞘脂藻黄素存在于许多具鞘蓝细菌物种中。过去的研究表明，该色素是在暴露于UV-A辐照下合成的。本研究调查了其他相关胁迫因素，包括热、渗透和氧化胁迫，对从石生荒漠结皮中分离出的克隆蓝细菌菌株（嗜球藻属）中鞘脂藻黄素合成的影响。胁迫实验在有UV-A辐照和无UV-A辐照的情况下均进行了。温度和光氧化条件的增加与UV-A共同作用导致鞘脂藻黄素产生速率协同增加。相比之下，在UV-A辐照下盐浓度的增加抑制了鞘脂藻黄素的合成。然而，与对温度和氧化胁迫的反应不同，在没有诱导鞘脂藻黄素的辐照时，细胞在渗透胁迫下合成的鞘脂藻黄素水平较低。这些结果表明，鞘脂藻黄素的诱导可能作为复杂胁迫反应途径的一部分受到调控，其中多种环境信号影响其合成。
