Fundamental study on in situ monitoring of environmental mutagens with Tradescantia

本文以紫露草雄蕊毛为材料，研究了(1)烷化剂的致突变性及其与X射线的协同效应，(2)马来酰肼(用作除草剂)的致突变性及其与X射线的相互作用，(3)空气污染物的致突变性，(4)自发突变率的变化，以及(5)新的检测系统。(1)甲烷磺酸乙酯(EMS)、甲磺酸甲酯(MMS)、硫酸二甲酯(DMS)、测定了N-乙基-N-亚硝基(ENU)和N-甲基-N-亚硝脲(MNU)，证实了EMS、MMS、DMS和MNU对X射线有明显的协同效应。关于(2)，发现顺丁烯二酸肼(MH)是一种诱变剂，在紫露草细胞中被过氧化物酶激活为诱变剂，当MH的激活被X射线抑制和不被X射线抑制时，它与X射线既有拮抗作用，又有协同作用。关于(3)，在氮气或空气/氮气混合物中用二氧化氮处理，用气体曝气室进行处理，但得到的结果不一致。臭氧的影响目前正在研究中。关于(4)，证实了温度条件下自发突变频率的一定程度的变化。关于(5)，在营养液循环生长箱中培养的无性系BNL 4430的带根花序幼芽被发现是最有效的诱变试验材料。

This study was carried out in 1993 to 1995 using the stamen hairs of Tradescantia, in order to investigate (1) the mutagenicities of alkylating agents and their synergistic effects with X rays, (2) the mutagenicity of maleic hydrazide (being used as herbicide) and its interactions with X rays, (3) the mutagenicities of air pollutants, and (4) variation of spontaneous mutation frequency, as well as to develop (5) a new testing system.As for (1), the mutagenicities of ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), dimethyl sulfate (DMS), N-ethyl-N-nitrosoures (ENU) and N-methl-N-nitrosourea (MNU) were determined, and EMS,MMS,DMS and MNU were confirmed to show clear synergistic effects with X rays. Concerning (2), maleic hydrazide (MH), a promutagen, was found to be activated into a mutagen in Tradescantia cells by peroxidase, and to act both antagonistically and synergistically with X rays when the activation of MH was inhibited and not inhibited by X rays, respectively. As for (3), treatments with nitrogen dioxide in nitrogen or air/nitrogen mixtures were conducted using a gas exposing chamber, but inconsistent results were obtained. The effect of ozone is now being investigated. About (4), a certain extent of variation in spontaneous mutation frequency due to temperature conditions was confirmed. Concerning (5), young inflorescence-bearing shoots with roots of clone BNL 4430 cultivated in the nutrient solution circulating growth chamber were found to be the most efficient materials for mutagenicity testings.