Wing Somatic Mutation Research Articles

Exposure to boron trioxide nanoparticles and ions cause oxidative stress, DNA damage, and phenotypic alterations in Drosophila melanogaster as an in vivo model.

Boron trioxide nanoparticles (B2 O3 NPs) have recently been widely used in a range of applications including electronic device technologies, acousto-optic apparatus fields, and as nanopowder for the production of special glasses. We propose Drosophila melanogaster as a useful in vivo model system to study the genotoxic risks associated with NP exposure. In this study, we have conducted a genotoxic evaluation of B2 O3 NPs (size average 55.52 ± 1.41 nm) and its ionic form in D.melanogaster. B2 O3 NPs were supplied to third instar larvae at concentrations ranging from 0.1-10mM. Toxicity, intracellular oxidative stress (reactive oxygen species, ROS), phenotypic alterations, genotoxic effect (via the wing somatic mutation and recombination test, SMART), and DNA damage (via Comet assay) were the end-points evaluated. B2 O3 NPs did not cause any mutagenic/recombinogenic effects in all tested non-toxic concentrations in Drosophila SMART. Negative data were also obtained with the ionic form. Exposure to B2 O3 NPs and its ionic form (at two highest concentrations, 2.5 and 5mM) was found to induce DNA damage in Comet assay. Additionally, ROS induction in hemocytes and phenotypic alterations were determined in the mouths and legs of Drosophila. This study is the first study reporting genotoxicity data in the somatic cells of Drosophila larvae, emphasizing the importance of D. melanogaster as a model organism in investigating the different biological effects in a concentration-dependent manner caused by B2 O3 NPs and its ionic form. The obtained in vivo results contribute to improvement the genotoxicity database on the B2 O3 NPs.

Genotoxic hazard assessment of cerium oxide and magnesium oxide nanoparticles in Drosophila

The use of metal oxide nanoparticles (NPs) is steadily spreading, leading to increased environmental exposures to many organisms, including humans. To improve our knowledge of this potential hazard, we have evaluated the genotoxic risk of cerium oxide (CeO2NPs) and magnesium oxide (MgONPs) nanoparticle exposures using Drosophila as an in vivo assay model. In this study, two well-known assays, such as the wing somatic mutation and recombination test (wing-spot assay) and the single-cell gel electrophoresis test (comet assay) were used. As a novelty, and for the first time, changes in the expression levels of a wide panel of DNA repair genes were also evaluated. Our results indicate that none of the concentrations of CeO2NPs increased the total spot frequency in the wing-spot assay, while induction was observed at the highest dose of MgONPs. Regarding the comet assay, both tested NPs were unable to induce single DNA strand breaks or oxidative damage in DNA bases. Nevertheless, exposure to CeO2NPs induced significant increases in the expression levels of the Mlh1 and Brca2 genes, which are involved in the double-strand break repair pathway, together with a decrease in the expression levels of the MCPH1 and Rad51D genes. Regarding the effects of MgONPs exposure, the expression levels of the Ercc1, Brca2, Rad1, mu2, and stg genes were significantly increased, while Mlh1 and MCPH1 genes were decreased. Our results show the usefulness of our approach in detecting mild genotoxic effects by evaluating changes in the expression of a panel of genes involved in DNA repair pathways.

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.

Adverse biological effects of ingested polystyrene microplastics using Drosophila melanogaster as a model in vivo organism

ABSTRACT The abundant presence and extensive use of polystyrene microplastics (PSMPs) has recently become a serious environmental concern, as impact of exposure to these substances on human health remains unknown. While in vitro studies yield data on adverse effect of PSMPs, in vivo approaches are more relevant for risk assessment. Drosophila melanogaster is one of the most genetically and experimentally accessible model organisms used in biology as an in vivo model. D. melanogaster was selected as a representative in vivo model organism to examine the genotoxic potential of PSMPs at 5 concentrations of three different sizes namely 4, 10, or 20 µm. In particular, the wing somatic mutation and recombination test (SMART), a scalable, time-efficient in vivo assay developed to study genotoxicity of various compounds in a rapid manner at low costs was used. The third–instar Drosophila larvae were exposed to PSMPs through food at 5 concentrations ranging from 0.01-10 mM. Viability (lethality), larval length, morphological deformations, locomotor activity (climbing behavior), and genotoxic effects were the end-points measured. Exposure to PSMPs at 4, 10, or 20 µm produced significant morphological defects, impaired climbing behavior, and genotoxicity as evidenced by the SMART test demonstrating induction of somatic recombination. Significant increases were observed in the frequency of total spots, suggesting that PSMPs might induce genotoxic activity predominantly via initiation of somatic DNA recombination in a concentration-dependent manner.

An Evaluation of the Genotoxic Effects of Electromagnetic Radiation at 900 MHz, 1800 MHz, and 2100 MHz Frequencies with a SMART Assay in Drosophila melanogaster

ABSTRACT With the development of today’s technology, the electromagnetic radiation spread by mobile phones and base stations is also rapidly increasing, and this causes serious concerns about the environment and human health. The Drosophila model organism is widely used in genetic toxicology studies because its genome is highly similar to the genes identified in human diseases. In this study, the genotoxic effects of radiofrequency electromagnetic radiation were evaluated by the wing Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster at 900 MHz, 1800 MHz, and 2100 MHz. The SMART method is based on the observation of genetic changes occurring in the trichomes of the Drosophila wings appearing as mutant clones under the microscope. Throughout the study, total clone parameters were evaluated by exposing the Drosophila larvae to electromagnetic fields for two, four, and six hours per day for two days. As a result of the study, it was observed that the number of mutant clones was statistically increased according to the negative control group in all applications except for the six-hour application at 1800 MHz.

Genotoxic analysis of nickel–iron oxide in Drosophila

It is known that nickel-iron oxide nanocomposite (NiFe2O4NP) is used in many important areas such as modern industry, biomedical applications, magnetic resonance imaging, construction of sensors, targeted drug treatment, and photoelectric devices in our life. In this study, we have carried out a genotoxic evaluation of NiFe2O4NP (30 nm) in Drosophila melanogaster by using the wing somatic mutation and recombination assay. For this purpose, third instar larvae carrying the recessive genes (flr3) and multiple wing hairs (mwh) in their third chromosomes were used. The larvae were fed at concentrations ranging from 25 µg/mL to 200 µg/mL. The genotoxic effects of NiFe2O4NPs were evaluated according to mutant trichomes resulting from genetic changes (mitotic recombination, deletion, point mutation, nondisjunction) on development of the wing imaginal discs. Mutant clone evaluations were performed based on small single spots, large single spots, and twin spots classifications. The results showed that significant increases were observed in the frequency of all spots, indicating that the highest concentration of nanoparticles was able to induce genotoxic activity in the wing spot assay of D. melanogaster.

Assessment of the antioxidant activity and genotoxicity of the extracts and isolated glycosides with a new flavonoid from Lotus aegaeus (Gris.) Boiss

Chemical composition and genotoxic properties of L. aegaeus (Griseb.) Boiss. which is a member of legumes and used as a cover crop, an antimicrobial agent for animal wounds and forage in Central Anatolia were detected for the first time. Nine secondary metabolites together with a new compound for nature were isolated from the n-butanol extract of Lotus aegaeus (Griseb.) Boiss aerial parts. The structures of the isolated compounds were clarified as a known cyanogenic glucoside, linamarin (1), 2 known saponins: wistariasaponin C (8) and wistariasaponin D (9), 5 known flavonoids: quercetin-3-O-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (2), quercetin-3-O-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside (3), kaempferol-3-O-β-d-galactopyranosyl-7-O-α-l-rhamnopyranoside (4), kaempferol-3-O-β-xylopyranosyl-(1→2)-α--l-rhamnopyranosyl-7-O-α-l-rhamnopyranoside (5), kaempferol 3-O-(5′'-acetyl) apiofuranoside 7-O-rhamnopyranoside(6) and a new flavonoid, kaempferol 3-O-(3′',5′'-diacetyl) apiofuranoside 7-O-rhamnopyranoside (7) by using 1D-2D Nuclear Magnetic Resonance (NMR) and Mass Spectroscopy (MS) methods. Antioxidant effects of the L. aegaeus (Griseb.) Boiss extracts and all isolated compounds were investigated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and superoxide (SO) radical scavenging tests. Quercetin glycosides (2/3) exhibited the strongest antioxidant ability. The genotoxicity of the extracts and some isolated compounds (1,4,6/7,9) were determined in Drosophila melanogaster by the in vivo wing somatic mutation and recombination test (SMART). All genotoxicity test results revealed that L. aegaeus is a reliable source for drug development researches.

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.

Lead modulated Heme synthesis inducing oxidative stress mediated Genotoxicity in Drosophila melanogaster

The mechanism of lead (Pb) modulated heme synthesis pathway induced oxidative stress mediated genotoxicity using standard (ST) and high bioactivation (HB) crosses of Drosophila melanogaster was addressed in the present study. Third instar larvae derived from the ST or HB crosses were reared in sub lethal concentrations of lead acetate (PbAc) treated food media and showed that Pb was readily taken up and accumulated in the said crosses. Pb modulated heme synthesis was evident by significant reductions of δ-aminolevulinic acid dehydratase (δ-ALA-D) and cytochrome P450 (CYP450) and increased accumulation of δ-aminolevulinic acid (δ-ALA). The results have also demonstrated that Pb induced oxidative stress by overproducing reactive oxygen species (ROS) and lipid peroxidation (LPO) and depletion of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione-s-transferase (GST). Wing somatic mutation and recombination test (SMART) using ST and HB crosses revealed that Pb is mutagenic and weakly recombinogenic. By employing larval hemocytes, there was an increase in percent of tail DNA in alkaline comet compared to that of neutral comet revealing the DNA single strand breaks were the products of Pb modulated heme synthesis pathway induced oxidative free radicals. Based on these findings, it can be concluded that Pb modulated heme synthesis pathway induces oxidative stress that mediates the genotoxicity in D. melanogaster.

Genotoxic evaluation of different sizes of iron oxide nanoparticles and ionic form by SMART, Allium and comet assay

In this study, the genotoxic potential of <50 nm, <100 nm iron oxide (Fe2O3) nanoparticles (IONPs) and ionic form were investigated using the wing somatic mutation and recombination test (SMART) and Allium and comet assays. In the SMART assay, different concentrations (1, 2, 5 and 10 mM) of NPs and ionic forms were fed to transheterozygous larvae of Drosophila melanogaster. No significant genotoxic effect was observed in <100 nm NPs and ionic form, while <50 nm IONPs showed genotoxicity at 1 and 10 mM concentrations. Allium cepa root meristems were exposed to five concentrations (0.001, 0.01, 0.1, 1 and 10 mM) of <50 nm and ionic forms for 4 h and three concentrations (2.5, 5 and 10 mM) for <100 nm of IONPs for 24 and 96 h. There was a statistically significant effect at 96 h at all concentrations of <100 nm IONPs. Similarly, <50 nm of IONPs and ionic forms also showed a statistically significant effect on mitotic index frequencies for all concentrations at 4 h. There was a dose-dependent increase in chromosomal abnormalities for IONPs and ionic form. Comet assay results showed time- and concentration-dependent increases in <100 nm NPs. There was a concentration-dependent increase in <50 nm NPs and ionic form ( p < 0.05). Consequently, the <50 nm of Fe2O3 was found toxic compared to 100 nm Fe2O3 and ionic form.

Assessment of the mutagenic, recombinogenic, and carcinogenic potential of amphotericin B in somatic cells of Drosophila melanogaster

Amphotericin B (AmB) is an antifungal antibiotic extracted from Streptomyces nodosus. Its fungicidal activity depends primarily on its binding to the sterol group that is present in fungal membranes. In view of the toxicity of this drug, the purpose of this study was to evaluate its mutagenic, carcinogenic, and recombinogenic activity, based on the wing somatic mutation and recombination test (SMART) and the epithelial tumor detection test (wts) applied to Drosophila melanogaster. Larvae were chronically treated with different concentrations of AmB (0.01, 0.02, and 0.04 mg/mL). The results revealed that AmB is a promutagen exhibiting increase in the number of spots on individuals from high bioactivation (HB) cross with a high level of cytochrome P450. The results also indicate that the main genotoxic event induced by AmB is recombinogenicity. Homologous recombination can act as a determinant at different stages of carcinogenesis. For verification of carcinogenic potential of this compound, larvae from the wts/mwh and wts/ORR, flr3 were treated with the same three AmB concentrations used in the SMART assay. The results did not provide evidence that AmB has carcinogenic potential in wts/mwh individuals. However, individuals from wts/ORR, flr3 developed tumors at the highest concentration tested.

Vernonanthura polyanthes leaves aqueous extract enhances doxorubicin genotoxicity in somatic cells of Drosophila melanogaster and presents no antifungal activity against Candida spp.

Vernonanthura polyanthes (Spreng.) A.J. Vega & Dematt. (Asteraceae), known as "assa-peixe", has been used in ethnomedicine for the treatment of various diseases such as bronchitis, pneumonia, hemoptysis, persistent cough, internal abscesses, gastric and kidney stone pain. Moreover, some studies demonstrated that species of Genus Vernonia present antifungal activity. Due to the biological relevance of this species, the aim of this study was to investigate the toxic, genotoxic, antigenotoxic and antifungal potential of V. polyanthes leaves aqueous extract in somatic cells of Drosophila melanogaster or against Candida spp. The aqueous extract of the plant showed no toxic, genotoxic and antigenotoxic activity in the experimental conditions tested using the wing somatic mutation and recombination test (SMART/wing). However, when the extract was associated with doxorubicin, used in this work as a positive control, the mutagenic potential of doxorubicin was enhanced, increasing the number of mutations in D. melanogaster somatic cells. In the other hand, no inhibitory activity against Candida spp. was observed for V. polyanthes leaves aqueous extract using agar-well diffusion assay. More studies are necessary to reveal the components present in the V. polyanthes leaves aqueous extract that could contribute to potentiate the doxorubicin genotoxicity.

Determination of mutagenicity of chemical compounds, physical factors and environmental pollutants by the Drosophila melanogaster wing somatic mutation and recombination test

A somatic mutation and recombination test (SMART) on the wing cells of Drosophila melanogaster is described in this article in detail. SMART can be used to evaluate the effect of various factors on the genome: physical (temperature, various types of radiation, electromagnetic fields), biogenic (genetic, physiological, infectious factors) and a wide range of chemical compounds. SMART is used as an in vivo version of the method for evaluating promutagenic and mutagenic properties of food, food supplements, potential drugs and cosmetics, and environmental pollutants. The method is based on the influence of the agents under study on the dividing cells of the wing imaginal discs of larvae heterozygous for recessive mutations, marking the wing cells. The mutations, multi wing hairs (mwh; 3 – 0.3) and flare (flr; 3 – 38.8), are located on the left arm of chromosome 3. The Drosophila melanogaster wing contains 24,400 cells arranged in two layers. Each normal cell has only one wing fiber. Recombination or mutational events in the cell leads to the formation of mutant spots/clones visible by microscopic analysis of the wing surface. The Drosophila and mammalian detoxication system is arranged on similar principles, which are based on the action of cytochrome P450. There are modifications to SMART, based on elevated cytochrome P450 expression, allowing more reliable extrapolation of the test results to mammals. Detailed recommendations for the use of the SMART method on the wing cells of Drosophila melanogaster presented in the paper can be used as a textbook in practice and for training purposes.

Assessment of the genotoxic potential of two zinc oxide sources (amorphous and nanoparticles) using the in vitro micronucleus test and the in vivo wing somatic mutation and recombination test

In this study, we evaluated the toxic and genotoxic potential of zinc oxide nanoparticles (ZnO NPs) of 20 nm and the mutagenic potential of these ZnO NPs as well as that of an amorphous ZnO. Toxicity was assessed by XTT colorimetric assay. ZnO NPs were toxic at concentrations equal to or higher than 240.0 μM. Genotoxicity was assessed by in vitro Cytokinesis Block Micronucleus Assay (CBMN) in V79 cells. ZnO NPs were genotoxic at 120.0 μM. The mutagenic potential of amorphous ZnO and the ZnO NPs was assayed using the wing Somatic Mutation and Recombination Test (SMART) of Drosophila melanogaster. In the Standard cross, the amorphous ZnO and ZnO NPs were not mutagenic. Nevertheless, Marker trans-heterozygous individuals from the High bioactivation cross treated with amorphous ZnO (6.25 mM) and ZnO NPs (12.50 mM) displayed a significant increased number of mutant spots when compared with the negative control. In conclusion, the results were not dose related and indicate that only higher concentrations of ZnO NPs were toxic and able to induce genotoxicity in V79 cells. The increase in mutant spots observed in D. melanogaster was generated due to mitotic recombination, rather than mutational events.

Genotoxic evaluation of bupivacaine and levobupivacaine in the Drosophila wing spot test.

Bupivacaine and levobupivacaine are amino amide local anesthetics commonly used in medical practice. Although bupivacaine consists of a racemic mixture of S (-)-bupivacaine and R (+)-bupivacaine enantiomers, levobupivacaine is comprised of pure S (-)-bupivacaine. It has been known that levobupivacaine is preferable to bupivacaine since it may cause cardiovascular and nervous system toxicity. For determining genotoxicity of these anesthetics, we used the wing somatic mutation and recombination test in Drosophila melanogaster. Three-day-old trans-heterozygous larvae were treated with bupivacaine and levobupivacaine. Analysis of the standard crosses indicated that bupivacaine and levobupivacaine did not exhibit mutagenic or recombinogenic activity until toxic doses have been reached at the larval stage. When we examined bupivacaine and levobupivacaine in the HB cross, bupivacaine did not exhibit any genotoxicity at high concentrations (500µg/mL), but levobupivacaine did exert genotoxicity at high concentrations (1000µg/mL)-depending on the substantial recombinogenic effect.

Analysis of genotoxic activity of ketamine and rocuronium bromide using the somatic mutation and recombination test in Drosophila melanogaster

The present study evaluated the mutagenic and recombinogenic effects of two commonly used anesthetic agents, ketamine and rocuronium bromide, in medicine using the wing somatic mutation and recombination test (SMART) in Drosophila. The standard (ST) cross and the high-bioactivation (HB) cross with high sensitivity to procarcinogens and promutagens were used. The SMART test is based on the loss of heterozygosity, which occurs via various mechanisms, such as chromosome loss and deletion, half-translocation, mitotic recombination, mutation, and non-disjunction. Genetic alterations occurring in the somatic cells of the wing's imaginal discs result in mutant clones in the wing blade. Three-day-old trans-heterozygous larvae with two recessive markers, multiple wing hairs (mwh) and flare (flr3), were treated with ketamine and rocuronium bromide. Analysis of the ST cross indicated that ketamine exhibited genotoxicity activity and that this activity was particularly dependent on homologous mitotic recombination at concentrations of 250μg/ml and above. Rocuronium bromide did not exert mutagenic and/or recombinogenic effects. In the HB cross, ketamine at a concentration of 1000μg/ml and rocuronium bromide at all concentrations, with the exception of 250μg/ml (inconclusive), exerted genotoxic effects, which could also be associated with the increase in mitotic recombination.

In vivo Genotoxicity of Four Synthetic Pyrethroids with Combinations of Piperonyl Butoxide (PBO) Using the Drosophila SMART Assay

In this study, the genotoxic effects of four synthetic pyrethroids (cypermethrin, cyphenothrin, deltamethrin, and permethrin) alone and their combinations with different rates of piperonyl butoxide (PBO) were studied using the wing somatic mutation and recombination test (SMART) of the Drosophila melanogaster. In the first stage, lethal concentration values (LC 25 or LC 50 ) of the synthetic pyrethroids and concentrations of PBO used for the synthetic pyrethroids were determined. Then, Drosophila larvae were exposed to lethal concentrations of synthetic pyrethroids and combinations with different rates of PBO (1:0.25, 1:0.5, 1:0.75, 1:1, and 1:2). According to the obtained results, alone and with the PBO of the mixtures of the four synthetic pyrethroids are not genotoxic when compared with the negative control. In addition, the PBO when used alone demonstrated negative results when exposed to 1, 5, and 25 ppm concentrations, while demonstrating positive result when exposed to 50 ppm concentration. However, the PBO did not show any co-genotoxic activity with the four tested synthetic pyrethroids. Results of this study will take an important place in human and environmental health with the new results for the PBO ratios in insecticide formulations.

In vivo genotoxicity assessment of titanium, zirconium and aluminium nanoparticles, and their microparticulated forms, in Drosophila

As in vivo system, we propose Drosophila melanogaster as a useful model for study the genotoxic risks associated with nanoparticle exposure. In this study we have carried out a genotoxic evaluation of titanium dioxide (TiO2), zirconium oxide (ZrO2) and aluminium oxide (Al2O3) nanoparticles and their microparticulated forms in D. melanogaster by using the wing somatic mutation and recombination assay. This assay is based on the principle that loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs and flare-3, can lead to the formation of mutant clones in treated larvae, which are expressed as mutant spots on the wings of adult flies. Third instar larvae were feed with TiO2, ZrO2 and Al2O3 nanoparticles, and their microparticulated forms, at concentrations ranging from 0.1 to 10mM. Although a certain level of aggregation/agglomeration was observed in solution, it must be noted than the constant digging activity of larvae ensures that treated medium pass constantly through the digestive tract ensuring exposure. The results showed that no significant increases in the frequency of all spots (e.g. small single, large single, twin, total mwh and total spots) were observed, indicating that these nanoparticles were not able to induce genotoxic activity in the wing spot assay of D. melanogaster. Negative data were also obtained with the microparticulated forms. This indicates that the nanoparticulated form of the selected nanomaterials does not modify the potential genotoxicity of their microparticulated versions. These in vivo results contribute to increase the genotoxicity database on the TiO2, ZrO2 and Al2O3 nanoparticles.

Metronidazole Induced DNA Damage in Somatic Cells of Drosophila melanogaster

The standard version of the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster was employed in order to evaluate the genotoxic potential of metronidazole (MTZ) as a function of exposure concentration. MTZ was administered by chronic feeding of 3-day-old larvae with the parenteral solution at 0, 500, 1000 and 2000 μg/ml until pupation. The marker-heterozygous progeny (mwh+/+flr3) with phenotypically wild-type wings was analyzed. Non significant differences were found between control and each MTZ concentration tested for single small spots (SSS) frequencies. Large single spots (LSS) and twin spots (TS) were significantly increased with the higher dose. MTZ treatments with 1000 and 2000 μg/ml also significantly increased the frequency of Total spots. These findings suggest that MTZ is genotoxic in the present experimental conditions and induces recombinagenesis and/or gene conversion, two major mechanisms that cause loss of heterocigosity and could play an important role in tumorigenesis and carcinogenesis processes.

Assessment of the in vitro and in vivo genotoxicity of extracts and indole monoterpene alkaloid from the roots of Galianthe thalictroides (Rubiaceae)

Roots of Galianthe thalictroides K. Schum. (Rubiaceae) are used in folk medicine in the State of Mato Grosso do Sul, Brazil, for treating and preventing cancer. To gain information about the genotoxicity of extracts (aqueous and EtOH), the CHCl₃ phase resulting from partition of the EtOH extract and the indole monoterpene alkaloid 1 obtained from this plant. The genotoxicity of 1 and extracts was evaluated in vivo through the Drosophila melanogaster wing Somatic Mutation and Recombination Test - SMART, while in vitro cytotoxic (MTT) and Comet assays were performed only with alkaloid 1. The results obtained with the SMART test indicated that the aqueous extract had no genotoxic activity. The EtOH extract was not genotoxic to ST descendants but genotoxic to HB ones. The CHCl₃ phase was genotoxic and cytotoxic. Alkaloid 1 showed significant mutational events with SMART, in the cytotoxicity assay (MTT), it showed a high cytotoxicity for human hepatoma cells (HepG2), whereas for the Comet assay, not showing genotoxic activity. The ethanol extract was shown to be genotoxic to HB descendants in the SMART assay, while the results obtained in this test for the monoterpene indole alkaloid 1 isolated from this extract.