Lhotka M A, Plewa M J, Gentile J M
Institute for Environmental Studies, University of Illinois, Urbana 61801.
Environ Mol Mutagen. 1987;10(1):79-88. doi: 10.1002/em.2850100109.
Tobacco, cotton, and carrot plant cell suspension cultures activated the promutagen m-phenylenediamine into a mutagen as detected by Salmonella typhimurium strain TA98 with the use of the plant cell/microbe coincubation assay. For each cell line, mid-log phase plant cells at a density of 100-150 mg/ml were coincubated for 1 hr with concentrations of m-phenylenediamine that ranged from 0.1 to 10 mumol per reaction tube in the preincubation test of the plant cell/microbe coincubation assay. Further experiments were conducted to optimize the activation response for each plant cell line. The density of plant cells in the reaction mixture, the time of coincubation of the reaction mixture, and the stage of the growth curve at which the plant cells were harvested for use in the reaction mixture all affected the response. Experiments that used the conditions determined as optimum for each plant cell line were then conducted. With each cell line, the optimized conditions enhanced the activation response that had been observed with the preliminary conditions. A ranking order based on the concentration-response curves indicated a relationship of tobacco cells much greater than carrot cells greater than cotton cells. Tobacco cells were able to activate m-phenylenediamine into a mutagen at concentrations of less than 10 nmol per plate when using TA98 as the genetic indicator organism. Finally, experiments to determine the type of genetic lesion induced by plant-activated m-phenylenediamine were conducted. By using five of the Ames strains, m-phenylenediamine was shown to be active in inducing revertants in strains TA1538 and TA98 following activation by tobacco cells under the optimized conditions. We conclude that m-phenylenediamine is activated by plant cells into a mutagen that primarily induces frameshift mutations.
烟草、棉花和胡萝卜的植物细胞悬浮培养物可将前诱变剂间苯二胺激活为诱变剂，这是通过鼠伤寒沙门氏菌TA98菌株利用植物细胞/微生物共培养试验检测到的。对于每种细胞系，在植物细胞/微生物共培养试验的预培养试验中，将处于对数中期、密度为100 - 150 mg/ml的植物细胞与每个反应管中浓度范围为0.1至10 μmol的间苯二胺共培养1小时。进行了进一步的实验以优化每种植物细胞系的激活反应。反应混合物中植物细胞的密度、反应混合物的共培养时间以及收获用于反应混合物的植物细胞时的生长曲线阶段均会影响反应。然后进行了使用为每种植物细胞系确定的最佳条件的实验。对于每种细胞系，优化后的条件增强了在初步条件下观察到的激活反应。基于浓度 - 反应曲线的排序表明，烟草细胞的激活能力远大于胡萝卜细胞，大于棉花细胞。当使用TA98作为遗传指示生物时，烟草细胞能够在每平板浓度低于10 nmol的情况下将间苯二胺激活为诱变剂。最后，进行了确定植物激活的间苯二胺诱导的遗传损伤类型的实验。通过使用五种艾姆斯菌株，结果表明，在优化条件下，间苯二胺在被烟草细胞激活后，对TA1538和TA98菌株具有诱导回复突变体的活性。我们得出结论，间苯二胺被植物细胞激活为一种主要诱导移码突变的诱变剂。
