There is considerable controversy with regard to the genotoxicity of glyphosate, with some reports stating that this compound is non-toxic for fish, birds and mammals. In this work, we used the comet assay to examine the genotoxicity of glyphosate isopropylamine (0.7, 7, 70 and 700 µM) in human lymphocytes, erythrocytes of Oreochromis niloticus and staminal nuclei of Tradescantia (4430) in vitro and in vivo. Cells, nuclei and fish that had and had not been exposed to 5 mM N-nitrosodiethylamine (NDEA) were used as positive and negative controls, respectively. Significant (p < 0.01) genetic damage was observed in vivo and in vitro in all cell types and organisms tested. Human lymphocytes and Tradescantia hairs showed lower genetic damage in vivo compared to in vitro, possibly because of efficient metabolization of the herbicide. In O. niloticus erythrocytes, significant (p < 0.001) genotoxicity was observed at > 7 µM, whereas in vitro, glyphosphate was genotoxic in human lymphocytes and Tradescantia hairs at > 0.7 µM. These results indicate that glyphosate is genotoxic in the cells and organisms studied at concentrations of 0.7-7 µM.

Glyphosate is noted for being non-toxic in fishes, birds and mammals (including humans). Nevertheless, the degree of genotoxicity is seriously controversial. In this work, various concentrations of a glyphosate isopropylamine salt were tested using two methods of genotoxicity assaying, viz., the pink mutation assay with Tradescantia (4430) and the comet assay with nuclei from staminal cells of the same plant. Staminal nuclei were studied in two different forms, namely nuclei from exposed plants, and nuclei exposed directly. Using the pink mutation assay, isopropylamine induced a total or partial loss of color in staminal cells, a fundamental criterion utilized in this test. Consequently, its use is not recommended when studying genotoxicity with agents that produce pallid staminal cells. The comet assay system detected statistically significant (p < 0.01) genotoxic activity by isopropylamine, when compared to the negative control in both the nuclei of treated plants and directly treated nuclei, but only the treated nuclei showed a dose-dependent increase. Average migration in the nuclei of treated plants increased, when compared to that in treated nuclei. This was probably due, either to the permanence of isopropylamine in inflorescences, or to the presence of secondary metabolites. In conclusion, isopropylamine possesses strong genotoxic activity, but its detection can vary depending on the test systems used.

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 hidrazide (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 80Mm 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. The English version of this paper is available too at: <A HREF="http://www.insp.mx/salud/index.html">http://www.insp.mx/salud/index.html </A>

Objetivo. Evaluar la genotoxicidad de N-nitroso dietilamina (NDEA), hidrazida málica (MH) y etil metano sulfonato (EMS), en núcleos de Tradescantia (clona 4430) por medio de la prueba del cometa y de la prueba de mutación rosa, en los pelos estaminales de la misma planta. Material y métodos. Las plantas de Tradescantia (clon 4430) fueron obtenidas del Laboratorio de Citogenética y Mutagénesis del Centro de ciencias de la Atmósfera de la Universidad Nacional Autónoma de México, tratadas con NDEA a 1, 5, 10 mM, MH a 1, 5, 10 mM y EMS a 15, 30 y 45 mM, y utilizadas en la prueba de mutación rosa y en la del cometa, en núcleos celulares de los pelos estaminales. En la primera, la lectura de los pelos estaminales se realizó de acuerdo con el método de Underbrink. En otros estudios, que han aplicado la prueba del cometa en plantas, existe la necesidad de romper la pared celular y separar los núcleos por gradiente de centrifugación; en este caso, los núcleos de las células de los pelos estaminales fueron extraídos por aplastamiento sin aplicar un procedimiento especial para romper la pared, colectados por filtración en una malla de nylon y sometidos a la prueba del cometa. La prueba t de Student se usó para analizar los datos obtenidos. Resultados. Ambas pruebas presentaron una gran sensibilidad a los mutágenos estudiados y hubo una relación evidente dosis-eventos rosa / longitud de la cauda. Aunque la prueba de mutación rosa en Tradescantia fue muy sensible a MH y EMS, no se detectaron dosis bajas de NDEA; en cambio, la prueba del cometa en la misma planta permite detectar fácilmente la actividad de todos los agentes estudiados. Conclusión. La prueba del cometa en los núcleos de las células de los pelos estaminales de Tradescantia es una útil herramienta para los estudios de monitoreo. Además, es simple, sensible y más rápida que la prueba de mutación rosa en la misma planta. El texto completo en inglés de este artículo también está disponible en: <A HREF="http://www.insp.mx/salud/index.html">http://www.insp.mx/salud/index.html </A>

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 hidrazide (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 80Mm 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. The English version of this paper is available too at: <A HREF="http://www.insp.mx/salud/index.html">http://www.insp.mx/salud/index.html </A>

Objetivo. Evaluar la genotoxicidad de N-nitroso dietilamina (NDEA), hidrazida málica (MH) y etil metano sulfonato (EMS), en núcleos de Tradescantia (clona 4430) por medio de la prueba del cometa y de la prueba de mutación rosa, en los pelos estaminales de la misma planta. Material y métodos. Las plantas de Tradescantia (clon 4430) fueron obtenidas del Laboratorio de Citogenética y Mutagénesis del Centro de ciencias de la Atmósfera de la Universidad Nacional Autónoma de México, tratadas con NDEA a 1, 5, 10 mM, MH a 1, 5, 10 mM y EMS a 15, 30 y 45 mM, y utilizadas en la prueba de mutación rosa y en la del cometa, en núcleos celulares de los pelos estaminales. En la primera, la lectura de los pelos estaminales se realizó de acuerdo con el método de Underbrink. En otros estudios, que han aplicado la prueba del cometa en plantas, existe la necesidad de romper la pared celular y separar los núcleos por gradiente de centrifugación; en este caso, los núcleos de las células de los pelos estaminales fueron extraídos por aplastamiento sin aplicar un procedimiento especial para romper la pared, colectados por filtración en una malla de nylon y sometidos a la prueba del cometa. La prueba t de Student se usó para analizar los datos obtenidos. Resultados. Ambas pruebas presentaron una gran sensibilidad a los mutágenos estudiados y hubo una relación evidente dosis-eventos rosa / longitud de la cauda. Aunque la prueba de mutación rosa en Tradescantia fue muy sensible a MH y EMS, no se detectaron dosis bajas de NDEA; en cambio, la prueba del cometa en la misma planta permite detectar fácilmente la actividad de todos los agentes estudiados. Conclusión. La prueba del cometa en los núcleos de las células de los pelos estaminales de Tradescantia es una útil herramienta para los estudios de monitoreo. Además, es simple, sensible y más rápida que la prueba de mutación rosa en la misma planta. El texto completo en inglés de este artículo también está disponible en: <A HREF="http://www.insp.mx/salud/index.html">http://www.insp.mx/salud/index.html </A>