Objective To test whether sodium arsenite can induce in vitro reverse mutation of Salmonella typhimurium histamine-auxotroph mutant. Methods Ames test was carded out with Salmonella typhimurium strains TA97,TA98,TA100 and TA102 by standard method with or without the liver microsomal enzyme activation system (+S9,-S9). Results At concentrations of sodium arsenite from 500.00 to 5000.00 μg/plate, no colonies were seen on the plates of TA97,TA98,TA100 or TA102, with or without the presence of S9. At concentrations of sodium arsenite of 0.01,0.10,10.00 μg/plate and with the presence of S9, twice as many colonies grew on the plates of TA102 as the negative control(P<0.05). Without S9 activation,twice as many colonies grew on the plates of TA100 as the negative control(P<0.05)at concentrations of sodium arsenite of 1.00,10.00 μg/plate(P<0.05). The reverse mutation colonies induced by sodium arsenite in TA98 strain were twice as many as negative control group at concentrations of 0.01,0.10 μg/plate(P<0.05). There was no obvious increase of the strain clones in the other(P0.05). Conclusions With and without S9 activation, the doses of 500.00,5000.00 μg/plate sodium arsenite resulted in a toxic effect and a reduction of the revertants among the strain. At concentrations of 0.01～10.00 μg/plate, sodium arsenite exhibited mutngenesis effects.%目的 体外观察亚砷酸钠诱发鼠伤寒沙门杆菌组氨酸营养缺陷型突变菌株的回复突变(Ames)作用,探讨低剂量亚砷酸钠的致突变性.方法 采用Ames试验中标准平板掺人法,检测不同剂量亚砷酸钠(5000.00、500.00、10.00、1.00、0.10、0.01μg/皿)及阳性、阴性对照在加与不加肝微粒体酶活化系统(+S9、-S9)条件下诱发TA97、TA98、TA100和TA102菌株的致突变作用.结果 +S9或-S9时,500.00、5000.00μg/皿亚砷酸钠作用下,TA97、TA98、TA100、TA102菌株均没有生长;+S9时,0.01、0.10、10.00μg/皿亚砷酸钠诱发TA102产生的回变菌落数与阴性对照相比均达到2倍以上(P<0.05),突变率(MR)分别为2.57、2.10、2.50,其他剂量组无明显增加(P0.05);在-S9条件下,1.00、10.00μg/皿亚砷酸钠诱发TA100菌株产生的回变菌落数与阴性对照相比均达到2倍以上(P<0.05),MR分别为2.18、2.27;0.01、0.10μg/皿亚砷酸钠诱发TA98菌株产生的回变菌落数与阴性对照相比均达到2倍以上(P<0.05),MR分别为3.17、4.22,其他剂量组未见明显增加(P0.05).结论 500.00、5000.00μg/皿亚砷酸钠抑制菌落生长,0.01～10.00μg/皿亚砷酸钠具有致突变性.
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