Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina.
Biol Trace Elem Res. 2012 May;146(2):246-55. doi: 10.1007/s12011-011-9244-1. Epub 2011 Nov 19.
In the present work, the response of tobacco (Nicotiana tabaccum L.) wild-type SR1 and transgenic CAT1AS plants (with a basal reduced CAT activity) was evaluated after exposure to the herbicide paraquat (PQ). Superoxide anion (O (2) (.-) ) formation was inhibited at 3 or 21 h of exposure, but H(2)O(2) production and ion leakage increased significantly, both in SR1 or CAT1AS leaf discs. NADPH oxidase activity was constitutively 57% lower in non-treated transgenic leaves than in SR1 leaves and was greatly reduced both at 3 or 21 h of PQ treatment. Superoxide dismutase (SOD) activity was significantly reduced by PQ after 21 h, showing a decrease from 70% to 55%, whereas catalase (CAT) activity decreased an average of 50% after 3 h of treatment, and of 90% after 21 h, in SR1 and CAT1AS, respectively. Concomitantly, total CAT protein content was shown to be reduced in non-treated CAT1AS plants compared to control SR1 leaf discs at both exposure times. PQ decreased CAT expression in SR1 or CAT1AS plants at 3 and 21 h of treatment. The mechanisms underlying PQ-induced cell death were possibly not related exclusively to ROS formation and oxidative stress in tobacco wild-type or transgenic plants.
在本工作中，评价了接触除草剂百草枯（PQ）后烟草（Nicotiana tabaccum L.）野生型 SR1 和转基因 CAT1AS 植株（基础 CAT 活性降低）的反应。在 3 或 21 小时暴露时，超氧阴离子（O2(-)）的形成受到抑制，但在 SR1 或 CAT1AS 叶片圆盘，H2O2 的产生和离子漏出明显增加。与 SR1 叶片相比，未经处理的转基因叶片中的 NADPH 氧化酶活性一直低 57%，在 PQ 处理 3 或 21 小时后大大降低。在 21 小时时，超氧化物歧化酶（SOD）活性因 PQ 而显著降低，从 70%降至 55%，而 CAT 活性在 3 小时处理后平均降低 50%，在 21 小时后降低 90%，在 SR1 和 CAT1AS 中分别降低。同时，在两个暴露时间，与对照 SR1 叶片圆盘相比，未经处理的 CAT1AS 植物中的总 CAT 蛋白含量降低。在 3 和 21 小时的处理中，PQ 降低了 SR1 或 CAT1AS 植物中的 CAT 表达。PQ 诱导的细胞死亡的机制可能不仅仅与 ROS 的形成和烟草野生型或转基因植物中的氧化应激有关。
