Busch D B, Bryan G T
Department of Pathology, University of Wisconsin Hospital and Clinics, Madison.
Environ Mol Mutagen. 1987;10(4):397-410. doi: 10.1002/em.2850100409.
Both histidine and dipeptides that can be converted to histidine can potentially interfere with the Ames test by increasing the number of spontaneous revertants. Such interference might be especially evident when urine and other biological samples are studied in this assay. We have developed a turbidimetric bioassay that utilizes a nonrevertible Salmonella typhimurium histidine auxotroph, NS1135. The assay is linear with histidine over at least a 300-fold range (0.015-5 micrograms/ml of L-histidine.HCl.H2O). Data indicate that several histidine-containing dipeptides can be utilized as efficiently as free histidine. Our data suggest that this assay may be used to measure biological samples accurately for their histidine content and thereby permit an adjustment for sample histidine during the setup of Ames assays, thus eliminating increased reversion caused by sample histidine.
组氨酸以及可转化为组氨酸的二肽都有可能通过增加自发回复突变体的数量来干扰艾姆斯试验。当在此试验中研究尿液和其他生物样品时，这种干扰可能尤为明显。我们开发了一种比浊生物测定法，该方法利用了一种不可回复的鼠伤寒沙门氏菌组氨酸营养缺陷型菌株NS1135。该测定法在至少300倍的范围内（0.015 - 5微克/毫升的L - 组氨酸盐酸盐一水合物）与组氨酸呈线性关系。数据表明，几种含组氨酸的二肽能够与游离组氨酸一样高效地被利用。我们的数据表明，这种测定法可用于准确测量生物样品中的组氨酸含量，从而在设置艾姆斯试验时对样品中的组氨酸进行校正，进而消除样品组氨酸引起的回复突变增加。
