氟化物对不同类型DNA紫外吸收光谱的影响

THE EFFECTS OF SODIUM FLUORIDE ON THE UV ABSORPTION SPECTRUM OF DIFFERENT TYPES OF DNA

以紫外吸收光谱法测定了氟化钠（ＮａＦ）与不同类型ＤＮＡ的直接结合作用。结果表明，ＮａＦ（０．１５－２３．６ｍｍｏｌ／Ｌ）可使线状小牛胸腺ＤＮＡ（２２４ｍｇ／Ｌ）及ＬａｍｄｓＤＮＡ的紫外吸收光谱特征发生明显改变，表现为吸收波长的明显位移及吸收强度的显著降低；而１０—８０ｍｍｏｌ／ＬＮａＦ未诱发环状ＰＢＲ３２２质粒ＤＮＡ紫外吸收光谱特征发生改变。从而较好地解释了以往氟遗传毒性研究中，哺乳动物细胞染色体损伤及基因突变试验多为阳性，而细菌基因回复突变试验呈阴性的结果。

The direct combination of sodium fluoride(NaF) to the different types of DNA was investigated using UV absorption spectrometry. The results showed that NaF (0.15-23.6mmol/L)could significantly change the UV absorption spectrum of the linar type fetal bovine thymus DNA (22.4 mg/L) and Lamds DNA(0.9mg/L). Its absorption peak was shifted and declined. NaF (10-80 mmol/L) could not change the UV absorption spectrum of the circular type PBR 322 DNA. These may explain the results of that NaF induce clastogenicity and mutation in mammalian cell assays but not in bacteria mutation tests.