Hideg E, Kálai T, Hideg K, Vass I
Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged.
Biochemistry. 1998 Aug 18;37(33):11405-11. doi: 10.1021/bi972890+.
In plants experiencing environmental stress, the formation of reactive oxygen is often presumed. In this study, singlet oxygen was detected in broad bean (Vicia faba) leaves that were photoinhibited in vivo. Detection was based on the reaction of singlet oxygen with DanePy (dansyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrole) yielding a nitroxide radical (DanePyO) which is EPR active and also features lower fluorescence compared to DanePy. The two (fluorescent and spin) sensor fuctions of DanePy are commensurate, which makes detecting singlet oxygen possible with a spectrofluorimeter in samples hard to measure with EPR spectroscopy [Kálai, T., Hideg, E., Vass, I., and Hideg, K. (1998) Free Radical Biol. Med. 24, 649-652]. We found that in leaves saturated with DanePy, the fluorescence of this double sensor was decreased when the leaves were photoinhibited by 1500 micromol m-2 s-1 photosynthetically active radiation. This fluorescence quenching is the first direct experimental evidence that photoinhibition of photosynthesis in vivo is accompanied by 1O2 production and is, at least partly, governed by the process characterized as acceptor side-induced photoinhibition in vitro.
在经历环境胁迫的植物中，通常推测会产生活性氧。在本研究中，在体内发生光抑制的蚕豆（Vicia faba）叶片中检测到了单线态氧。检测基于单线态氧与丹磺酰 - 2,2,5,5 - 四甲基 - 2,5 - 二氢 - 1H - 吡咯（DanePy）的反应，生成一种氮氧自由基（DanePyO），它具有电子顺磁共振（EPR）活性，并且与DanePy相比荧光较低。DanePy的两种（荧光和自旋）传感功能是相称的，这使得用荧光分光光度计在难以用EPR光谱测量的样品中检测单线态氧成为可能[Kálai, T., Hideg, E., Vass, I., and Hideg, K. (1998) Free Radical Biol. Med. 24, 649 - 652]。我们发现，在用DanePy饱和的叶片中，当叶片被1500微摩尔·米⁻²·秒⁻¹光合有效辐射光抑制时，这种双传感器的荧光会降低。这种荧光猝灭是光合作用在体内的光抑制伴随着单线态氧产生的首个直接实验证据，并且至少部分受体外被称为受体侧诱导光抑制的过程所支配。
