RESUMO
Pepper seeds (Capsicum annuum L.) var. B12 were mutagenized by four presoaking treatments in ten concentrations of ethyl methane sulfonate (EMS) to determine the sensitivity of the first generation (M1) to mutagens. The spectrum of mutations and induced variability for various quantitative traits, including germination, percent plant height, injury occurrence, survival ratio, first three fruits weight, and number of seeds per first fruit, were observed in the M1 generation. Our results indicated that all of the test parameters decreased with increasing EMS concentration, except for seedling injury. There were significant differences in germination ratio, LD50, plant height, percent injury, and survival ratio among the tested presoaking treatment. The LD50 was 1% EMS in seeds that were not presoaked (T1) and seeds presoaked for 12 h before treating with EMS (T3). In contrast, the LD50 was 0.5% EMS in seeds presoaked for 6 h (T2) and seeds presoaked in water for 6 h then incubated at 28°C for 12 h before EMS treatment (T4). Five dwarf plants were observed in mutagenized seeds without presoaking as compared to control seeds (at the maturity stage of the control plant).
Assuntos
Capsicum/efeitos dos fármacos , Capsicum/crescimento & desenvolvimento , Metanossulfonato de Etila/toxicidade , Capsicum/anatomia & histologia , Frutas/anatomia & histologia , Frutas/efeitos dos fármacos , Germinação/efeitos dos fármacos , Dose Letal Mediana , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Fatores de TempoRESUMO
Cynara scolymus L. (Asteraceae), popularly known as artichoke, has been widely used in herbal medicine for the treatment of hepatic diseases. The genotoxicity of C. scolymus L. leaf extract (LE) and the ability to modulate the genetic toxicity of the alkylating agent ethyl methanesulfonate (EMS) were assessed using the comet assay on Chinese hamster ovary cells. Genotoxicity was evaluated after 1- and 24-h treatments using four different LE concentrations: 0.62, 1.25, 2.5, and 5.0 mg/mL. Antigenotoxicity was assessed for pretreatment, simultaneous treatment, and post-treatment. All doses used led to a significant increase in the frequency of DNA damage, after exposure for 1 and 24 h. In the antigenotoxicity experiments, LE reduced the frequency of DNA damage induced by EMS in the simultaneous treatment only. However, the lowest dose was more protective than higher concentrations. Flavonoids and phenolic compounds are, probably, the C. scolymus constituents responsible for its genotoxic and antigenotoxic effects.
Assuntos
Cynara scolymus/química , Dano ao DNA/efeitos dos fármacos , Metanossulfonato de Etila/toxicidade , Extratos Vegetais/farmacologia , Alquilantes/toxicidade , Animais , Células CHO , Sobrevivência Celular , Ensaio Cometa , Cricetinae , Mutagênicos/toxicidadeRESUMO
Ethyl methanesulphonate (EMS) is a mutagenic alkylating agent that induces marked elevations of sperm abnormalities in mice. In this paper, we report the ultrastructural findings on the morphology of the seminiferous epithelium of mice resulting from EMS administration. Eight- to twelve-weeks-old male mice were injected intraperitoneally with EMS at 200 mg kg(-1) body weight daily for five consecutive days. Analysis of smears of epididymis and semi-thin sections of testes revealed that the more suitable specimens for the ultrastructural analysis were tissues of mice killed at the third week, following EMS administration. At this time, the spermatid was the damaged cell type. Abnormalities were mainly observed in the morphology of the nucleus, the acrosome, chromatin distribution and in the arrangement of the cytoplasmic microtubules, and binucleated spermatids were also observed. EMS has the capacity to penetrate the blood-testis barrier, and thus it can damage post-meiotic spermatogenic cells. However, morphological abnormalities could be the consequence of damage exerted on the differentiated spermatogonia stage, the most sensitive spermatogenic cell to the action of chemical agents or drugs. Our findings contribute to elucidate the action mechanism of the damage exerted by EMS administration on the germinal male cells.
Assuntos
Metanossulfonato de Etila/toxicidade , Mutagênicos/toxicidade , Epitélio Seminífero/efeitos dos fármacos , Epitélio Seminífero/ultraestrutura , Animais , Masculino , Camundongos , Espermátides/efeitos dos fármacos , Espermátides/ultraestruturaRESUMO
Vanillin (VA) modulates the genotoxicity of chemical and physical agents in a complex manner. Previous studies indicate that VA inhibits the mutagenicity but increases the mitotic homologous recombination caused by at least some genotoxic agents. In the present study, we have evaluated the effects of VA on the repair of lethal damage produced by three genotoxins, N-ethyl-N-nitrosourea (ENU), ethyl methanesulfonate (EMS), and mitomycin C (MMC), using the DNA repair test (DRT) in Drosophila melanogaster. VA, 0.25% and 0.5% (w/v), increased the toxicity of MMC and EMS in repair-deficient flies, as measured by a decrease in the proportion of male to female progeny in the DRT; sex ratios decreased from 18-48% for MMC and 21-97% for EMS. These effects may be caused by the inhibition of nonhomologous DNA end joining caused by VA. In contrast to the results with MMC and EMS, VA protected against the lethality of ENU in repair-defective flies, as measured by a 43-207% increase in the survival of male flies in the DRT. It was inferred that the protective effect was due to VA modulating stages prior to the induction of ENU lesions in DNA, including modulating the antioxidant properties of VA and/or to its interference with the metabolic activation and/or detoxification of specific genotoxins. The results from this study indicate that the characterization of VA as a promising agent for preventing damage to genes and chromosomes should be tempered by observations that VA can increase the toxicity of chemical agents.
Assuntos
Benzaldeídos/farmacologia , Reparo do DNA/efeitos dos fármacos , Drosophila melanogaster/efeitos dos fármacos , Mutagênicos/toxicidade , Animais , Antimutagênicos/farmacologia , Dano ao DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Drosophila melanogaster/genética , Metanossulfonato de Etila/toxicidade , Etilnitrosoureia/toxicidade , Feminino , Masculino , Mitomicina/toxicidade , Recombinação Genética/efeitos dos fármacosRESUMO
Vanillin (VA), the world's major flavoring compound used in food industry and confectionery products - that has antimutagenic and anticarcinogenic activity against a variety of mutagenic/carcinogenic agents - was tested for the interval between the formation of premutational lesion and it is finalization as a DNA lesion. The overall findings using co-treatment protocols in SMART test suggest that VA can lead to a significant protection against the general genotoxicity of ethylmethanesulphonate (EMS), N-ethyl-N-nitrosourea (ENU), N-methyl-N-nitrosourea (MNU) and bleomycin sulphate (BLEO). Considering MNU, ENU and EMS the desmutagenic activity observed could result from VA-stimulation of detoxification, via induction of glutathione S-transferase. However, the protector effect related to BLEO could be attributed to its powerful scavenger ability, which has the potential to prevent oxidative damage induced by BLEO.
Assuntos
Alquilantes/toxicidade , Antimutagênicos/toxicidade , Benzaldeídos/farmacologia , Mutação/efeitos dos fármacos , Recombinação Genética , Animais , Bleomicina/toxicidade , Cromossomos , Cruzamentos Genéticos , Relação Dose-Resposta a Droga , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Metanossulfonato de Etila/toxicidade , Etilnitrosoureia/toxicidade , Feminino , Marcadores Genéticos , Masculino , Metilnitrosoureia/toxicidade , Testes de MutagenicidadeRESUMO
Agaricus blazei Murrill ss. Heinem, known as the sun mushroom or himematsutake, is a basidiomycete native to Brazil, which is popular for its medicinal properties. The aim of this study was to test hexane extracts (one fraction and its four sub-fractions) of A. blazei for bioactivity in cultured mammalian cells (CHO-K1). The comet assay, the colony forming assay (CFA) and CHO/HGPRT gene mutation assay were used respectively to determine genotoxicity, cytotoxicity and antimutagenicity of these extracts at different concentrations. The cells were incubated in culture medium and treated for 3h according to the standard protocol for each assay. The DNA damage-inducing agent ethylmethane sulfonate (EMS) was utilized as the positive control and also in combination with extracts to test for a protective effect. Statistical analysis of the data was performed using analysis of variance (ANOVA) and Tukey's test. A relationship between cytotoxicity and genotoxicity could be established and two extracts EH6B and EH6D showed a protective tendency, while the others did not, with the primary extract EH6 causing the most substantial damage to genetic material. These findings warrant more in-depth studies of the active principles of this mushroom.
Assuntos
Agaricus/química , Antimutagênicos/farmacologia , Antineoplásicos/farmacologia , Hipoxantina Fosforribosiltransferase/genética , Animais , Antimutagênicos/isolamento & purificação , Antineoplásicos/isolamento & purificação , Células CHO , Ensaio Cometa , Cricetinae , Dano ao DNA/efeitos dos fármacos , Metanossulfonato de Etila/antagonistas & inibidores , Metanossulfonato de Etila/toxicidade , Mutagênicos/toxicidade , Ensaio Tumoral de Célula-TroncoRESUMO
Vanillin (VA; C8H8O3) is a flavoring agent that in previous studies has both increased and decreased the genotoxicity of chemical agents, depending on the nature of both the agent and the genetic event measured. The ability of VA to modulate the mutagenicity and recombinogenicity of three different monoalkylating agents, N-ethyl-N-nitrosourea (ENU), N-methyl-N-nitrosourea (MNU), and ethyl methanesulfonate (EMS), and the intercalating agent bleomycin (BLEO) was examined using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. While neither the mutagenicity nor the recombinagenicity of ENU or MNU was modified by posttreatment with VA, EMS-induced genetic toxicity was enhanced by as much as 30%. This overall enhancement included a synergistic increase in mitotic recombination and a lesser decrease in mutation. Posttreatment with VA also produced an increase in the genotoxicity of BLEO, which was characterized by increases of 120% and 180% for 0.5% and 1% VA, respectively. This enhancement was restricted to an increase in recombinational events, since no alteration in BLEO-induced mutation was observed. The data suggest that the major VA-modulatory action on genotoxicity in D. melanogaster is related to its synergistic effects on somatic recombination, which has a greater consequence on overall genotoxicity than its antimutagenic effects. Since the SMART assay is specifically sensitive to mitotic crossing-over, our data suggest that VA promotes toxicant-induced homologous recombination, at least in the proliferative cells of Drosophila.
Assuntos
Antimutagênicos/farmacologia , Benzaldeídos/farmacologia , Proliferação de Células/efeitos dos fármacos , Drosophila melanogaster/genética , Etilnitrosoureia/toxicidade , Mutação/efeitos dos fármacos , Recombinação Genética , Alquilantes/toxicidade , Animais , Cruzamentos Genéticos , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/crescimento & desenvolvimento , Sinergismo Farmacológico , Metanossulfonato de Etila/toxicidade , Feminino , Aromatizantes/farmacologia , Masculino , Metilnitrosoureia/toxicidade , Mitose , Mosaicismo , Testes de MutagenicidadeRESUMO
OBJECTIVE: To assess the genotoxic activity of N-nitroso diethylamine (NDEA), maleic hydrazide (MH), and ethyl methane sulfonate (EMS) using two systems: the comet assay on nuclei from Tradescantia, and the pink mutation test on Tradescantia staminal hairs (clone 4430). MATERIAL AND METHODS: Tradescantia cups was obtained from Laboratorio de Citogenética y Mutagénesis del Centro de Ciencias de la Atmósfera de la Universidad Nacional Autónoma de México and treated with: N-nitroso diethylamine (NDEA) at 1, 5, 10 mM, maleic hydrazide (MH) at 1, 5, 10 mM and ethyl methane sulfonate (EMS) at 15, 30 and 45 mM; and used in both pink mutation assay and comet assay using cellular nuclei from Tradescantia staminal hairs. The observation of staminal hair was realized along eight days (6-14) after treatment), flowers produced day 14 after treatment were utilized done according to Underbrink. In previous reports on plants, were comet assay was used, breaking cellular wall and separating by centrifugation gradient are necessary. Here, nuclei from staminal hairs were obtained by squashing the cells (is not necessary to utilize to break special procedure cellular wall), collected using a nylon mesh of 80 Mm and next the comet assay was applied. Student's T test was the statistical test used for analyzing the comet assay data. RESULTS: Both assays showed a great sensitivity to the studied mutagens. A relationship between the dose-pink event and the dose-tail length was evident. Even though the Tradescantia mutation assay is a sensitive test with MH and EMS, low doses of NDEA were not able to induce a significant increase in the pink event frequencies; however, the comet assay was able to detect the mutagenic effect of NDEA at the same dose. Thus, it is clear that the comet assay is highly sensitive to the lowest dose of chemical mutagens. CONCLUSIONS: The comet assay on nuclei from Tradescantia staminal hairs is a useful tool to monitor genotoxic agents; it is simple, highly sensitive, and faster than the pink mutation test.