Xu Maojun, Dong Jufang, Zhang Xinbo
Institute of Natural Resource and Environmental Sciences, Zhejiang Gongshang University, Hangzhou 310035, China.
Sci China C Life Sci. 2008 Aug;51(8):676-86. doi: 10.1007/s11427-008-0095-8. Epub 2008 Aug 3.
Heat shock (HS, 40 degrees C, 10 min) induces hypericin production, nitric oxide (NO) generation, and hydrogen peroxide (H(2)O(2)) accumulation of Hypericum perforatum suspension cells. Catalase (CAT) and NO specific scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) suppress not only the HS-induced H(2)O(2) generation and NO burst, but also the HS-triggered hypericin production. Hypericin contents of the cells treated with both NO and H(2)O(2) are significantly higher than those of the cells treated with NO alone, although H(2)O(2) per se has no effects on hypericin production of the cells, which suggests the synergistic action between H(2)O(2) and NO on hypericin production. NO treatment enhances H(2)O(2) levels of H. perforatum cells, while external application of H(2)O(2) induces NO generation of cells. Thus, the results reveal a mutually amplifying action between H(2)O(2) and NO in H. perforatum cells. CAT treatment inhibits both HS-induced H(2)O(2) accumulation and NO generation, while cPTIO can also suppress H(2)O(2) levels of the heat shocked cells. The results imply that H(2)O(2) and NO may enhance each other's levels by their mutually amplifying action in the heat shocked cells. Membrane NAD(P)H oxidase inhibitor diphenylene iodonium (DPI) and nitric oxide synthase (NOS) inhibitor S,S'-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea (PBITU) not only inhibit the mutually amplifying action between H(2)O(2) and NO but also abolish the synergistic effects of H(2)O(2) and NO on hypericin production, showing that the synergism of H(2)O(2) and NO on secondary metabolite biosynthesis might be dependent on their mutual amplification. Taken together, data of the present work demonstrate that both H(2)O(2) and NO are essential for HS-induced hypericin production of H. perforatum suspension cells. Furthermore, the results reveal a special interaction between the two signal molecules in mediating HS-triggered secondary metabolite biosynthesis of the cells.
热激（40℃，10分钟）可诱导贯叶连翘悬浮细胞中金丝桃素的产生、一氧化氮（NO）的生成以及过氧化氢（H₂O₂）的积累。过氧化氢酶（CAT）和NO特异性清除剂2-（4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物（cPTIO）不仅抑制热激诱导的H₂O₂生成和NO爆发，还抑制热激引发的金丝桃素产生。用NO和H₂O₂处理的细胞中金丝桃素含量显著高于仅用NO处理的细胞，尽管H₂O₂本身对细胞的金丝桃素产生没有影响，这表明H₂O₂和NO在金丝桃素产生方面具有协同作用。NO处理可提高贯叶连翘细胞的H₂O₂水平，而外源施加H₂O₂可诱导细胞产生NO。因此，结果揭示了贯叶连翘细胞中H₂O₂和NO之间的相互放大作用。CAT处理抑制热激诱导的H₂O₂积累和NO生成，而cPTIO也可抑制热激细胞的H₂O₂水平。结果表明，H₂O₂和NO可能通过热激细胞中的相互放大作用来提高彼此的水平。膜NAD（P）H氧化酶抑制剂二亚苯基碘鎓（DPI）和一氧化氮合酶（NOS）抑制剂S,S'-1,3-亚苯基-双（1,2-乙二基）-双异硫脲（PBITU）不仅抑制H₂O₂和NO之间的相互放大作用，还消除H₂O₂和NO对金丝桃素产生的协同效应，表明H₂O₂和NO对次生代谢物生物合成的协同作用可能依赖于它们的相互放大。综上所述，本研究数据表明，H₂O₂和NO对于热激诱导贯叶连翘悬浮细胞产生金丝桃素都是必不可少的。此外，结果揭示了这两种信号分子在介导热激引发的细胞次生代谢物生物合成中的特殊相互作用。
