Campesato V R, Graf U, Reguly M L, de Andrade H H
Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil.
Environ Mol Mutagen. 1997;29(1):91-7.
Integerrimine (ITR), a pyrrolizidine alkaloid from Senecio brasiliensis, was tested for genotoxicity using the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster. The compound was administered by chronic feeding (48 hours) of 3-day-old larvae. Two different crosses involving the markers flare (flr) and multiple wing hairs (mwh) were used, that is, the standard (ST) cross and the high bioactivation (HB) cross, which has a high cytochrome P450-dependent bioactivation capacity. In both crosses, the wings of two types of progeny were analyzed, that is, inversion-free marker heterozygotes and balancer heterozygotes carrying multiple inversions. ITR was found to be equally potent in inducing spots in a dose-related manner in the marker heterozygotes of both crosses. This indicates that the bioactivation capacity present in larvae of the ST cross is sufficient to reveal the genotoxic activity of ITR. In the balancer heterozygotes of both crosses, where all recombinational events are eliminated due to the inversions, the frequencies of induced spots were considerably reduced which documents the recombinagenic activity of ITR. Linear regression analysis of the dose response relationships for both genotypes shows that 85% to 90% of the wing spots are due to mitotic recombination.
从巴西千里光中提取的吡咯里西啶生物碱整数精（ITR），利用黑腹果蝇的翅体细胞突变和重组试验（SMART）对其遗传毒性进行了检测。该化合物通过对3日龄幼虫进行48小时的慢性喂食来给药。使用了涉及标记物耀斑（flr）和多翅毛（mwh）的两种不同杂交组合，即标准（ST）杂交组合和具有高细胞色素P450依赖性生物活化能力的高生物活化（HB）杂交组合。在这两种杂交组合中，分析了两种类型后代的翅膀，即无倒位标记杂合子和携带多个倒位的平衡子杂合子。发现ITR在两种杂交组合的标记杂合子中均以剂量相关的方式同等有效地诱导斑点。这表明ST杂交组合幼虫中存在的生物活化能力足以揭示ITR的遗传毒性活性。在两种杂交组合的平衡子杂合子中，由于倒位消除了所有重组事件，诱导斑点的频率显著降低，这证明了ITR的重组活性。对两种基因型的剂量反应关系进行线性回归分析表明，85%至90%的翅斑是由有丝分裂重组引起的。
