稀土元素对怀槐悬浮培养细胞异黄酮合成及氧化还原态的影响

Effects of Rare Earth Elements on Isoflavone Biosynthesis and Redox Status of Maackia amurensis Cells in Suspension Cultures

在培养基中添加不同浓度的硝酸铈和硝酸镧,并检测怀槐细胞悬浮培养过程中异黄酮含量、苯丙氨酸裂解酶(PAL)酶活、还原型谷胱甘肽和氧化型谷胱甘肽含量的变化,以探讨稀土元素对怀槐细胞合成异黄酮的影响和机制.结果表明,20mmolL-1硝酸铈和10mmolL-1硝酸镧较适合诱导怀槐悬浮培养细胞合成异黄酮;细胞培养过程中,硝酸铈和硝酸镧诱导异黄酮合成的变化趋势与PAL酶的活性变化一致;氧化还原态变化分析发现,硝酸铈和硝酸镧处理的细胞中GSH/GSSG比例分别在d3和d2达到最大值,是同期对照的1.46和1.47倍,而异黄酮含量则在d4和d3达到最大值,分别达到了271.42μgg-1(DW)和279.32μgg-1(DW).研究结果显示,怀槐细胞悬浮培养中添加稀土元素提高次生代谢产物异黄酮的合成可能与稀土元素诱导细胞氧化还原态的改变有关.

To interpret the effects and mechamism of rare earth elements on isoflavone biosynthesis, the changes in isoflavone concentration, phenylalanine -ammonia lyase activity, and GSH and GSSG concentrations in the suspension cultures of Maackia arnurensis were studied after Ce（ NO3 ）3 and La（ NO3 ）3 were added into the liquid medium. The rusuhs showed that the optimum concentrations of Ce （NO3 ）3 and La（ NO3 ）3 for isoflavone biosynthesis were 20 mmol· L^-1 and 10 mmol· L^-1, respectively. During the culture period, the change in isoflavone biosynthesis caused by the elieitation of Ce（ NO3 ）3 or La（ NO3 ）3 was consistent with the activity of PAL. The highest accumulation of isoflavone genistein occurred on day 4 for the elieitation of Ce （NO3） 3 and day 3 for La（ NO3 ）3, and was 271.42 μg·g^- 1 （DW） and 279.32 μg· g^- 1 （DW） , respectively. The analysis of cellular redox status showed that the treatment of Ce（ NO3 ）3 and La（ NO3 ）3 changed the levels of GSH and GSSG in the cultured cells. The ratio of GSH/GSSG reached a peak value on day 3 for Ce（NO3）3 and day 2 for La（NO3）3, and it was enhanced by 0.46 and 0.47 times as compared to the control. The obtained results suggested an increase in isoflavone biosynthesis by the rare earth elements could be related to the change in cell redox status.