Petrilli F L, De Flora S
Appl Environ Microbiol. 1977 Apr;33(4):805-9. doi: 10.1128/aem.33.4.805-809.1977.
Four hexavalent and two trivalent chromium compounds were tested for toxicity and mutagenicity by means of the Salmonella typhimurium/mammalian-microsome test. All hexavalent compounds yielded a complete inhibition of bacterial growth at doses of 400 to 800 mug/plate, a significant increase of his(+) revertant colonies at doses ranging from 10 to 200 mug, and no effect at doses of less than 10 mug. The distinctive sensitivity of the four Salmonella strains tested (TA1535, TA1537, TA98, and TA100) suggested that hexavalent chromium directly interacts with bacterial deoxyribonucleic acid by causing both frameshift mutations and basepair substitutions. The latter mutations, which are prevalent, are amplified by an error-prone recombinational repair of the damaged deoxyribonucleic acid. On the average, 1 mumol of hexavalent chromium yielded approximately 500 revertants of the TA100 strain, irrespective of the compound tested (sodium dichromate, calcium chromate, potassium chromate, or chromic acid). The mutagenic potency of the hexavalent metal was not enhanced by adding the microsomal fraction of rat hepatocytes, induced either with sodium barbital or with Aroclor 1254. The two trivalent compounds (chromium potassium sulfate and chromic chloride), with or without the microsomal fraction, were neither toxic nor mutagenic for the bacterial tester strains.
通过鼠伤寒沙门氏菌/哺乳动物微粒体试验，对四种六价铬化合物和两种三价铬化合物进行了毒性和致突变性测试。所有六价铬化合物在剂量为400至800微克/平板时均能完全抑制细菌生长，在10至200微克剂量范围内能显著增加组氨酸（+）回复菌落数，而在低于10微克剂量时无影响。所测试的四种沙门氏菌菌株（TA1535、TA1537、TA98和TA100）的独特敏感性表明，六价铬通过引起移码突变和碱基对替换直接与细菌脱氧核糖核酸相互作用。后一种突变很普遍，通过受损脱氧核糖核酸的易错重组修复而被放大。平均而言，无论测试的化合物是重铬酸钠、铬酸钙、铬酸钾还是铬酸，1微摩尔六价铬能产生约500个TA100菌株的回复体。添加经巴比妥钠或多氯联苯混合物1254诱导的大鼠肝细胞微粒体部分，并不会增强六价金属的致突变能力。两种三价化合物（硫酸铬钾和氯化铬），无论有无微粒体部分，对细菌测试菌株既无毒性也无致突变性。
