Department of Biological Sciences, University at Buffalo, Buffalo, New York 14260, USA.
Environ Sci Technol. 2011 Oct 15;45(20):8958-64. doi: 10.1021/es200863j. Epub 2011 Sep 14.
Plant responses to natural stresses have been the focus of numerous studies; however less is known about plant responses to artificial (i.e., man-made) stress. Chlortetracycline (CTC) is widely used in agriculture and becomes an environmental contaminant when introduced into soil from manure used as fertilizer. We show here that in the model plant Arabidopsis (Arabidopsis thaliana), root uptake of CTC leads to toxicity, with growth reductions and other effects. Analysis of protein accumulation and in vivo synthesis revealed numerous changes in soluble and membrane-associated proteins in leaves and roots. Many representative proteins associated with different cellular processes and compartments showed little or no change in response to CTC. However, differences in accumulation and synthesis of NAD-malic enzyme in leaves versus roots suggest potential CTC-associated effects on metabolic respiration may vary in different tissues. Fluorescence resonance energy transfer (FRET) analysis indicated reduced levels of intracellular calcium are associated with CTC uptake and toxicity. These findings support a model in which CTC uptake through roots leads to reductions in levels of intracellular calcium due to chelation. In turn, changes in overall patterns and levels of protein synthesis and accumulation due to reduced calcium ultimately lead to growth reductions and other toxicity effects.
植物对自然胁迫的反应一直是众多研究的重点；然而，人们对植物对人为（即人为）胁迫的反应知之甚少。金霉素（CTC）在农业中被广泛使用，当它从用作肥料的粪便中引入土壤时，就会成为环境污染物。我们在这里表明，在模式植物拟南芥（Arabidopsis thaliana）中，根吸收 CTC 会导致毒性，表现为生长减少和其他影响。对蛋白质积累和体内合成的分析揭示了叶片和根中可溶性和膜相关蛋白的大量变化。许多与不同细胞过程和隔室相关的代表性蛋白质对 CTC 的反应几乎没有变化或没有变化。然而，叶片与根中 NAD-苹果酸酶的积累和合成的差异表明，代谢呼吸可能会因不同组织而存在潜在的 CTC 相关影响。荧光共振能量转移（FRET）分析表明，细胞内钙水平的降低与 CTC 的摄取和毒性有关。这些发现支持了这样一种模型，即 CTC 通过根吸收会因螯合作用而导致细胞内钙水平降低。反过来，由于钙的减少，导致蛋白质合成和积累的整体模式和水平发生变化，最终导致生长减少和其他毒性影响。
