Drosophila Wing Somatic Mutation Research Articles

Genotoxicity and cytotoxicity evaluation of two thallium compounds using the Drosophila wing somatic mutation and recombination test

Thallium (Tl) is a heavy and toxic metal and a byproduct of several human activities, such as cement production, mining, and coal combustion. Thallium is found in fruits, vegetables, and animal fodder with high Tl contamination; therefore, it is an environmental pollution issue and a toxicological contamination problem for human beings and other organisms when exposed to it. The mutagenic potential of Tl and its compounds is controversial, and there are few in vivo studies on its effects. We conducted the animal bioassay Drosophila wing somatic mutation and recombination test (SMART) to test for genotoxicity and assessed the genotoxic effects of Tl acetate (TlCH3COO) and Tl sulfate (Tl2SO4) on Drosophila melanogaster. Third instar larvae from the SMART standard cross (ST) were fed Tl acetate [0.2, 2, 20, 200, 600 and 1200 μM] and Tl sulfate [0.2, 2, 20, 200, and 600 μM]. Hexavalent chromium [CrO3, 500 μM] served as the positive control, and Milli-Q water served as the negative control. Only the high Tl2SO4 [600 μM] concentration resulted in genotoxicity with 87.6% somatic recombination, and both salts disrupted cell division of wing imaginal disc cells, showing the expected cytotoxic effects. Genotoxic risks due to high metal levels by bioaccumulation of Tl+1 or its compounds require further evaluation with other in vivo and in vitro assays.

Genotoxicity assessment of four novel quinazoline-derived trypanocidal agents in the Drosophila wing somatic mutation and recombination test.

Chagas disease, caused by the protozoan Trypanosoma cruzi, has increased in the world due to migration, travelling and climate change; at present, the principal problem is that common trypanocidal agents have resulted in toxic or inconvenient side effects. We tested for genotoxicity in the standard (ST) and high bioactivation (HB) crosses of Drosophila wing somatic mutation and recombination test, four novel trypanocidal agents derived from 2, 4, 6-triaminquinazoline (TAQ): 2,4-diamino-6 nitro-1,3 diazonaftalene (S-1QN2-1), 2,4-diacetamino-6-amino 1,3 diazonaftalene (D-1), N6-(4,methoxybenzyl)quinazoline-2,4,6-triamine (GHPM) and N6-[4-(trifluoromethoxy)benzyl]quinazoline-2,4,6-triamine (GHPMF) at 1.9, 3.9, 7.9 and 15 µM, respectively. Also, high-pressure liquid chromatography (HPLC) analysis was run to determine the remanence of either drug in flare, and Oregon R(R)-flare flies emerged from treated larvae. S-1QN2-1 showed genotoxicity only in the ST cross, increasing the small, large and total spot frequencies at all concentrations and twin spots only at 1.9 µM; D-1 and GHPM showed significant increments of large spots only at 15 µM in the ST cross; GHPMF was not genotoxic at any concentration or either cross. In the mwh clones accumulated distribution frequencies analysis, associated with disrupted cell division, S-1QN2-1 caused alterations in the ST cross at all concentrations but only at 15 µM in the HB cross; D-1 caused alterations at 3.9, 7.9 and 15 µM in the ST cross and at 1.9 and 15 µM in the HB cross; GHPM caused alterations at 7.9 and 15 µM in the ST cross and also at 1.9, 3.9 and 7.9 µM in the HB cross; GHPMF caused those alterations at all concentrations in the ST cross and at 1.9, 3.9 and 7.9 µM in the HB cross. The HPLC results indicated no traces of either agent in the flare and Oregon R(R)-flare flies. We conclude that S-1QN2-1 is clearly genotoxic, D-1 and GHPM have an unclear genotoxicity and GHPMF was not genotoxic; all quinazoline derivatives disrupted cell division. GHPMF is a good candidate to be tested in other genotoxicity and cytotoxic bioassays. The differences in the genotoxic activity of these trypanocidal agents are correlated with differences in their chemical structure.

81 A new series of biologically active DNA minor groove binders based on bisbenzimidazole and benzimidazole-pyrrole motives

As we reported earlier, dimeric bisbenzimidazoles DB(n) (Ivanov et al., 2011a) were able to noncovalently bind in the DNA minor groove and displayed inhibitory activity at low concentrations toward three different DNA-dependent enzymes (Susova et al., 2010; Ivanov et al., 2011b; Cherepanova et al., 2011; Tunitskaya et al., 2011). However, these compounds had a substantial drawback: a low solubility in water solutions, which prevent their potential use in vivo as biologically active preparations. Therefore, for the new minor groove binder series, additional groups were added into the molecule structures for the sake of hydrophility and DNA affinity improvement. A DBP(n) series contains piperazine cycle in the oligomethylene linker which connects bisbenzimidazole fragments of molecule together. A DBPy(n) series have a pyrrole and benzimidazole cycles combination in their structure (Figure 1). DBP(n) (n = 1–4) compounds were studied as inhibitors of calf thymus DNA topoisomerase I (topo-I). All of them inhibited topo-I activity at 1–5 μM concentrations, besides, at concentrations over 5 μM, the inhibitory activities of DBP(n) were few times higher than that of DB(n). It was found that dimeric bisbenzoimidazoles DBP(1–3) were not mutagenic. They were inactive in the point mutagenesis assessment using the Ames test (with Salmonella Typhimurium bacteria as the tested object) and did not display mutagenic or recombinogenic properties in the Drosophila wing somatic mutation and recombination test (SMART). All the compounds of series were evaluated for cytotoxicity in the MTT test on breast cancer MCF-7, large bowel adenocarcinoma HCT-116, noncancer HEK-293 cell lines and on primary murine fibroblasts. All the tested DBP( n ) were not toxic up to concentrations of 100 μM. Contrary, the one tested compound from DBPy(n) series, DBPy(4) (n = 4), showed substantial cytotoxicity against cancer HCT-116 and human leukemic K-562 cell lines with an IC50 of 1–2 μM. Judging by the combination of such criterions as water solubility, topo-I inhibition activity and mutagenicity, it would be safe to assume that dimeric bisbenzoimidazoles of DBP(n) series are more perspective minor groove binders than previously synthesized DB( n ).

Genotoxicity studies in the ST cross of the Drosophila wing spot test of sunflower and soybean oils before and after frying and boiling procedures

Sunflower and soybean oils were tested for genotoxicity in the Drosophila wing somatic mutation and recombination assay. Results indicate that both oils produce genotoxic effects when tested without any previous frying or boiling processes. Boiling sunflower oil during fifteen, thirty and sixty minutes significantly increased its genotoxic response; nevertheless, after frying potatoes this oil showed a significant decrease in the genotoxic activity. On the other hand, boiling and frying soybean oil in the same conditions results in a decrease of its genotoxic potential. We have also detected that the amount of total polar materials increases significantly in oils submitted to frying or boiling process. Nevertheless, in oils obtained after frying potatoes, the amount of TPM was higher than after boiling. It is suggested that this effect is probably due to the amount of non-volatile TPM, the fatty acid composition of the oils, the types of frying oil, the high frying temperature and time, and the number of boiling and frying. This is the first study reporting genotoxicity data in Drosophila for the boiling and frying of both sunflower and soybean oils.

Genotoxicity testing of Cecropia obtusifolia extracts in two in vivo assays: The wing somatic mutation and recombination test of Drosophila and the human cytokinesis-block micronucleus test

Cecropia obtusifolia Bertol. (Cecropiaceae) is a tree that grows in secondary vegetation in the tropical rain forest along both coasts of Mexico. Its leaves are used in folk medicine for the treatment of diabetes mellitus type 2. The aim of the present studies was the evaluation of possible genotoxic effects of the aqueous extract from the leaves of Cecropia obtusifolia by means of two different experimental assay models: the wing somatic mutation and recombination test in flies and the micronucleus test from lymphocytes obtained from patients treated with the extract. No toxicity was found to be induced by the leaves of Cecropia obtusifolia. The Drosophila wing somatic mutation and recombination test (SMART) was applied in the standard version with basal biotransformation activity as well as in a variant version with increased cytochrome P450-dependent bioactivation capacity. The ranges of exposure concentrations for these genotoxicity experiments were between 0.82 and 13.32 mg/ml. The extract did not produce any genotoxic effect; however it showed a non significant antigenotoxic effect. The human micronucleus assay in vivo was performed with cultured lymphocytes obtained from six diagnosed type 2 diabetic patients treated daily with 13.5 g of the aqueous extract between 32 and 85 days. No statistically significant increases in cytotoxicity and/or genotoxicity between control and diabetic blood samples were observed.

A phytotherapeutic extract of Equisetum myriochaetum is not genotoxic either in the in vivo wing somatic test of Drosophila or in the in vitro human micronucleus test

Equisetum myriochaetum is a Mexican plant used in folk medicine to treat kidney diseases and type 2 diabetes mellitus. The main constituents of the phytoextract are flavonol glycosides (kaempferol), phytoesterols and carbohydrates. In this study, phytotherapeutic extracts from Equisetum myriochaetum were investigated for genotoxicity in the in vivo wing spot test in Drosophila melanogaster and in the in vitro human micronucleus test. No acute toxicity of the phytoextract could be determined in Drosophila or in human lymphocytes in culture, ranging from 0.78 μg/ml to 3700 μg/ml for the wing assay and between 12.5 μg/ml and 500 μg/ml for the micronucleus test. The Drosophila wing somatic mutation and recombination test (SMART) was applied in the standard version with basal biotransformation activity as well as in a variant version with increased cytochrome P450-dependent bioactivation capacity. The ranges of exposure concentrations for these genotoxicity experiments were between 0.78 μg/ml and 500 μg/ml. The human micronucleus test in vitro was performed with cultured lymphocytes obtained from four healthy donors. The concentrations assayed for these experiments ranged from 12.5 μg/ml to 500 μg/ml. No statistically significant increase was observed between treated series when compared with a concurrent negative (water solvent) control series in either assay. The results demonstrate clearly that the phytotherapeutic extract from Equisetum myriochaetum, under the experimental conditions tested, is not genotoxic in the in vivo experiments or in the in vitro studies.

Recombinogenic activity of 10 chemical compounds in male germ cells of Drosophila melanogaster

The Drosophila melanogaster male germ cells are sensitive to the recombinogenic activity of chemical compounds. In our experiments, we have employed four recessive markers located on the 2nd chromosome: dumpy ( dp, 13.0), black ( b, 48.5), cinnabar ( cn, 57.5), and brown ( bw, 104.5); b and cn flank the centromere. Three-day-old larvae, heterozygous for these markers, were treated chronically by oral administration with the test compounds. The chemicals already shown to be positive or negative in the assay systems to test chemical agents in D. melanogaster are three carcinogens (4-nitroquinoline N-oxide, hydroxylamine HCl, and acrylamide), four herbicides (maleic hydrazide, alachlor, trifluralin, and amitrol), and three insecticides (endrin, piperonyl butoxide, and allethrin). In our study, some compounds induced recombinogenic effects in Drosophila premeiotic male germ cells, and comparison of our results with those reported in the literature with the Drosophila wing somatic mutation and recombination assay showed that the somatic cells and the germinal cells have a differential response to the defined compounds.

Genotoxic effects of eugenol, isoeugenol and safrole in the wing spot test of Drosophila melanogaster

In the present study, the phenolic compounds eugenol, isoeugenol and safrole were investigated for genotoxicity in the wing spot test of Drosophila melanogaster. The Drosophila wing somatic mutation and recombination test (SMART) provides a rapid means to evaluate agents able to induce gene mutations and chromosome aberrations, as well as rearrangements related to mitotic recombination. We applied the SMART in its standard version with normal bioactivation and in its variant with increased cytochrome P450-dependent biotransformation capacity. Eugenol and safrole produced a positive recombinagenic response only in the improved assay, which was related to a high CYP450-dependent activation capacity. This suggests, as previously reported, the involvement of this family of enzymes in the activation of eugenol and safrole rather than in its detoxification. On the contrary, isoeugenol was clearly non-genotoxic at the same millimolar concentrations as used for eugenol in both the crosses. The responsiveness of SMART assays to recombinagenic compounds, as well as the reactive metabolites from eugenol and safrole were considered responsible for the genotoxicity observed.

Genotoxicity is modulated by ascorbic acid: Studies using the wing spot test in Drosophila

The ability of ascorbic acid (Vitamin C) to modulate the genotoxic action of several mutagens was investigated in the wing spot test of Drosophila melanogaster. In this assay, 3-day-old transheterozygous larvae for the multiple wing hairs ( mwh, 3-0.3) and flare ( flr, 3-38.8) genes were treated with three reference mutagenic compounds, namely cobalt chloride (CoCl 2), 4-nitroquinoline 1-oxide (4-NQO) and potassium dichromate (K 2Cr 2O 7). The results obtained show that the three reference mutagens tested were clearly genotoxic in the Drosophila wing somatic mutation and recombination test (SMART). None of the three concentrations tested of ascorbic acid (25, 75 and 250 mM) induced significant increases in the frequency of the mutant clones recorded. When co-treatment experiments with ascorbic acid were carried out, different results were found. Thus, ascorbic acid was effective in reducing the genotoxicity of K 2Cr 2O 7 virtually to the control level; on the contrary, it did not show any antigenotoxic effect on the genotoxicity of 4-NQO. Finally, co-treatments with CoCl 2 and ascorbic acid show a significant increase in the frequency of mutant clones over the values obtained with CoCl 2 alone.

Genotoxicity Testing of Some Metals in the Drosophila Wing Somatic Mutation and Recombination Test

Genotoxicity Testing of Some Metals in the Drosophila Wing Somatic Mutation and Recombination Test

Genotoxicity testing of some metals in the Drosophila wing somatic mutation and recombination test.

Genotoxicity testing of some metals in the Drosophila wing somatic mutation and recombination test.

Taxanes: the genetic toxicity of paclitaxel and docetaxel in somatic cells of Drosophila melanogaster.

In this study, the taxanes, paclitaxel and docetaxel were investigated for genotoxicity in the wing spot test of Drosophila melanogaster. These relatively new drugs are used in cancer therapy and show great promise in the treatment of a variety of cancers. Their major cellular target is the alpha,beta-tubulin dimer but, unlike other spindle poisons, they stabilize microtubules by a shift towards assembly, producing nonfunctional microtubule bundles. The Drosophila wing Somatic Mutation and Recombination Test (SMART) provides a rapid means to evaluate agents able to induce gene mutations and chromosome aberrations, as well as rearrangements related to mitotic recombination. We applied the standard version of SMART (with normal bioactivation) and a variant version with increased cytochrome P450-dependent biotransformation capacity. In the standard assay, docetaxel was found to be aneuploidogenic; this was effectively abolished by a high cytochrome P450-dependent detoxification capacity. This suggests, as previously reported, the involvement of this family of enzymes in the detoxification of docetaxel rather than in its activation. In contrast, paclitaxel was clearly non-genotoxic at the same (millimolar) concentrations as used for docetaxel in both crosses. The weak responsiveness of SMART assays to aneugenic compounds, the weaker ligand and assembly action of paclitaxel and the more rapid reversibility of the microtubules formed with this compound, may have caused the negative response observed in the present study.

Genotoxicity testing of different types of beverages in the drosophila wing somatic mutation and recombination test

Five wines and one brandy of Spanish origin as well as three herbal teas and ordinary black tea were tested for genotoxicity in the wing Somatic Mutation And Recombination Test (SMART) which makes use of the two recessive wing cell markers multiple wing hairs ( mwh) and flare ( flr 3) on the left arm of chromosome 3 of Drosophila melanogaster. 3-day-old larvae trans-heterozygous for these two markers were fed the beverages at different concentrations and for different feeding periods using Drosophila instant medium. Somatic mutations or mitotic recombinations induced in the cells of the wing imaginal discs give rise to mutant single or twin spots on the wing blade of the emerging adult flies showing either the mwh phenotype or/and the flr phenotype. One of the red wines showed a clear genotoxic activity that was not due to its ethanol content. Two herbal teas ( Urtica dioica, Achillea millefolium) and black tea ( Camellia sinensis) proved to be weakly genotoxic as well. Furthermore, it was shown that quercetin and rutin, two flavonols present in beverages of plant origin, also exhibited weak genotoxic activity in the somatic cells of Drosophila. These results demonstrate that Drosophila in vivo somatic assays can detect the genotoxicity of complex mixtures such as beverages. In particular, it is possible to administer these test materials in the same form as that in which they are normally consumed.

Thirty compounds tested in the Drosophila wing spot test

The Drosophila wing somatic mutation and recombination test (SMART) was evaluated for its suitability in genotoxicity screening by testing 30 chemicals. Of the 2 crosses used, the mwh-flr 3 cross turned out to be more convenient than the previously used mwh-flr cross. Based on the experience gained with both acute exposures and chronic exposures of different duration, we suggest that the optimal strategy in genotoxicity screening is to start with chronic exposure of 3-day-old larvae for 48 h (that is, until pupation). Only for unstable compounds and very volatile compounds and gases are acute treatments, including inhalation, recommended. In general, a qualitative evaluation of the genotoxicity of a compound in the wing assay is possible with as few as 1–2 different exposure concentrations. A more quantitative evaluation of genotoxicity, based upon dose-response data, can often be achieved with as few as 3–4 concentrations. The results reported here were obtained in 2 different laboratories, demonstrating that the wing spot test is easily transferable to other laboratories. The experience gained indicates that the assay has now been developed to an extent that a coordinated international comparative validation study is desirable.

Genotoxicity testing of antiparasitic nitrofurans in the Drosophila wing somatic mutation and recombination test

Nifurtimox and eight structurally related 5-nitrofuran compounds active against Trypanosoma cruzi were tested for genotoxicity in the wing somatic mutation and recombination test in Drosophila melanogaster. Nifurtimox, compound ada and compound 1B were clearly mutagenic and recombinogenic whereas the remaining six compounds were negative. In contrast to the situation in bacterial mutagenicity tests, nitroreductase activity is probably not decisive for the genotoxicity of these compounds in Drosophila. The three non-genotoxic nitrofurans with high antiparasitic activity are promising candidates for the replacement of nifurtimox. However, these compounds require further genotoxicity testing in eukaryotic assay systems for a final evaluation.

The Drosophila wing somatic mutation and recombination test (SMART): Effects of different treatment durations and of different strains

The Drosophila wing somatic mutation and recombination test (SMART): Effects of different treatment durations and of different strains