Integrative analysis in toxicological assessment of the insecticide Malathion in Allium cepa L system / Análise integrativa na avaliação toxicológica do inseticida Malation no sistema Allium cepa L

For many centuries human populations have been suffering and trying to fight with disease-bearing mosquitoes. Emerging and reemerging diseases such as Dengue, Zika, and Chikungunya affect billions of people around the world and recently has been appealing to control with chemical pesticides. Malathion (MT) is one of the main pesticides used against mosquitoes, the vectors of these diseases. This study aimed to assess cytotoxicity and mutagenicity of the malathion for the bioindicator Allium cepa L. using a multivariate and integrative approach. Moreover, an appendix table was compiled with all available literature of insecticides assessed by the Allium cepa system to support our discussion. Exposures during 48h to 0.5 mg mL-¹ and 1.0 mg mL-¹ MT were compared to the negative control (distilled water) and positive control (MMS solution at 10 mg L-¹). The presence of chromosomal aberrations, micronuclei frequency, and mitotic index abnormalities was evaluated. Anaphase bridges were the alterations with higher incidence and presented a significantly elevated rate in the concentration of 0.5 mg mL-¹, including when compared to the positive control. The integrative discriminant analysis summarizes that MT in assessed concentrations presented effects like the positive control, corroborating its potential of toxicity to DNA. Therefore, it is concluded that MT in its pure composition and in realistic concentrations used, has genotoxic potential in the biological assessment of A. cepa cells. The multivariate integrative analysis was fundamental to show a whole response of all data, providing a global view of the effect of MT on DNA.

Por muitos séculos, as populações humanas sofrem e tentam combater os mosquitos transmissores de doenças. Doenças emergentes e reemergentes como Dengue, Zika e Chikungunya afetam bilhões de pessoas em todo o mundo e, recentemente, vem apelando ao controle com pesticidas químicos. O Malation (MT) é um dos principais pesticidas usados contra mosquitos, vetores dessas doenças. O objetivo deste estudo foi avaliar a citotoxicidade e a mutagenicidade do MT para o bioindicador Allium cepa L. usando uma abordagem multivariada e integrativa. Além disso, uma tabela suplementar foi compilada com toda a literatura disponível de inseticidas avaliada pelo sistema Allium cepa para apoiar nossa discussão. Exposições ao MT durante 48h a 0,5 mg mL-¹ e 1,0 mg mL-¹ foram comparadas a um controle negativo (água destilada) e um controle positivo (10 mg L-¹ de MMS). Foram avaliadas a presença de aberrações cromossômicas, frequência de micronúcleos e anormalidades no índice mitótico. As pontes anafásicas foram as alterações com maior incidência e apresentaram uma taxa significativamente elevada na concentração de 0,5 mg mL-¹, inclusive quando comparadas ao controle positivo. A análise discriminante integrativa resume que o MT nas concentrações avaliadas apresentou efeitos semelhantes ao controle positivo, corroborando seu potencial de toxicidade para o DNA. Portanto, conclui-se que o MT, em sua composição pura e nas concentrações realistas utilizadas, possui potencial genotóxico na avaliação biológica de células de A. cepa. A análise integrativa multivariada foi fundamental para mostrar uma resposta completa de todos os dados, fornecendo uma visão global do efeito da MT no DNA.

Competition of onion genotypes in the soil and climatic conditions of Guarapuava, State of Paraná

The use of genotypes more adapted to climatic conditions can contribute to increase the yield of onion producers. The goal of this study was to evaluate the agronomic performance of 15 onion genotypes in the soil and climatic conditions of Guarapuava, state of Paraná. The study was conducted in the experimental area of Horticulture, Cedeteg campus, Universidade Estadual do Centro-Oeste (UNICENTRO), Guarapuava, state of Paraná, Brazil, from July to November 2018. The experimental design used was randomized blocks, with four replications, and the treatments consisted of four commercial cultivars Optima F1, Bella Dura, Sirius F1, Soberana F1 and eleven experimental genotypes N1, N2, N3, N4, N5, N6, N7, N8, N9, AF4241 and AF4243. Biometric characteristics of the plants, production components and early flowering were evaluated. Plants presented between 6 and 9 leaves, in which N1, N3, N4 and N6 had less than 7 leaves, differing statistically from the others. The cultivar Optima F1 and the genotypes N2, N3, N5, N6, N7 and N8 presented the tallest plants, with 66.1 to 76.0 cm. The pseudostem diameter did not differ significantly between genotypes, showing values between 15.2 and 20.4 mm. Total productivity was higher in genotypes N2, N6, N5, N4, N3, N7 with values from 43.6 to 50.3 t ha-1. The highest average bulb mass was found in N2, N4, N6, Sirius F1, Optima F1 and Soberana F1

Evaluation of cytotoxicity and genotoxicity of Hancornia speciosa latex in Allium cepa root model / Avaliação da citotoxicidade e genotoxicidade do látex de Hancornia speciosa usando o modelo da raiz de Allium cepa

Abstract The latex obtained from Hancornia speciosa Gomes (Mangabeira tree) is widely used in traditional medicine to treat a variety of diseases, including diarrhea, ulcer, gastritis, tuberculosis, acne and warts. In this study, the cytotoxicity and genotoxicity effects of H. speciosa latex on the root meristem cells of Allium cepa were examined. Onion bulbs were exposed to different concentrations of latex and then submitted to microscopic analysis using Giemsa stain. Water was used as a negative control and sodium azide as a positive control. The results showed that, under the testing conditions, the mitotic index (MI) of the onion roots submitted to latex treatment did not differ significantly from the negative control, which suggests that the latex is not cytotoxic. Low incidence of chromosome aberrations in the cells treated with H. speciosa latex was also observed, indicating that the latex does not have genotoxic effect either. The MI and the chromosome aberration frequency responded to the latex concentration, requiring more studies to evaluate the dosage effect on genotoxicity. The results indicate that in tested concentrations H. speciosa latex is probably not harmful to human health and may be potentially used in medicine.

Resumo O látex obtido de Hancornia speciosa é amplamente utilizado na medicina popular para tratar uma variedade de doenças, tais como: diarreia, úlcera, gastrite, tuberculose, acne e verrugas. Nesse estudo, foram avaliados os efeitos citotóxicos e genotóxicos do látex de H. speciosa sobre as células meristemáticas das raízes de Allium cepa. Os bulbos das cebolas foram expostos a diferentes concentrações de látex e depois submetidos à analise microscópica usando o corante Giemsa. A água foi usada como controle negativo e a ázida sódica como controle positivo. Os resultados mostraram que o índice mitótico (IM) das raízes de cebola submetidas ao tratamento com látex, nas condições testadas, não diferiram significativamente do controle negativo, e sugerem que o látex não é citotóxico. Também foi observada uma baixa incidência de aberrações cromossômicas nas células tratadas com látex de H. speciosa, o que sugere que o látex também não possui efeito genotóxico. O IM e a frequência de aberrações cromossômicas foram dependentes da concentração de látex. Outros estudos devem ser realizados para avaliar o efeito da dose na genotoxidade. Os resultados indicam que o látex de mangabeira, nas concentrações testadas, provavelmente não é danoso para saúde humana e pode ter potencial para ser usado na medicina.

Alterations in the mitotic index of Allium cepa induced by infusions of Pluchea sagittalis submitted to three different cultivation systems

We evaluated the antiproliferative effect of infusions from Pluchea sagittalis using the Allium cepa test. Infusions in three concentrations (2.5, 5, and 25 g dm-3) of leaves cultivated in three environments (in vitro, acclimatized growth chamber, and field) were used. Six onion bulbs were used for each of the eight treatments, and the mitotic index was obtained from 6000 cells per treatment. In conclusion, leaf infusions of P. sagittalis cultivated in the field have a high antiproliferative activity, as well as the cultivation system influences the antiproliferative potential.

Avaliou-se o efeito antiproliferativo de infusões de Pluchea sagittalis usando o teste de Allium cepa. Foram usadas infusões em três concentrações (2,5, 5 e 25g dm-3) de folhas cultivadas em três ambientes (in vitro, sala de crescimento climatizada e em campo). Foram usados seis grupos de bulbos para cada um dos 8 tratamentos e o os índices mitóticos foram obtidos a partir de 6000 células por tratamento. Concluiu-se que a infusão de folhas de P. sagittalis cultivadas em campo possui grande atividade antiproliferativa, bem como o sistema de cultivo de plantas influencia o potencial antiproliferativo.

Ability of Allium cepa L. root tips and Tradescantia pallida var. purpurea in N-nitrosodiethylamine genotoxicity and mutagenicity evaluation

N-nitroso compounds, such as N-nitrosodiethylamine (NDEA), can be formed by the reaction of secundary amines with nitrosating agents, and are suspected to be involved in tumors in humans. NDEA has been considered a weak carcinogen in genotoxic assays probably due to the inefficient nitrosamine activation system that is used and/or to the efficient repair system. In this work, we evaluated the sensibility of Allium cepa L. root tips and Tradescantia stamen hair mutation assay (Trad-SH) using Tradescantia pallida var. purpurea for NDEA (0.1; 0.5; 5 and 25mM) genotoxicity and mutagenicity induction. Allium cepa L. was treated with different NDEA concentrations for 3h, for 3 consecutive days, including negative control (distilled water) and positive control maleic hydrazide (MH 30mg/mL). After treatment, the roots were hydrolyzed, squashed, and the mitotic index (MI) and cytological abnormalities were scored. The results revealed a cytostatic effect of NDEA (0.5 and 5mM), showing a significant reduction in the MI. Chromosome stickiness suggests a NDEA toxic effect. T. pallida purpurea did not respond to mutagens with a dose-dependent pattern. In conclusion, our study indicates that the root tips of Allium cepa L. have sensibility to detect NDEA genotoxicity, but not for Trad-SH test.

Nitrocompostos, como N-nitrosodietilamina (NDEA), podem ser formados pela reação entre uma amina secundária e agentes nitrosantes e são suspeitos de estarem envolvidos na formação de tumores em humanos. NDEA é considerada um carcinógeno fraco e ensaios genotóxicos provavelente pela utilização de um sistema de ativação ineficiente e/ou pela utilização de um eficiente sistema de reparo. Neste trabalho, nós avaliamos a sensibilidade de ensaios com Alliu cepa L. e Tradescantia pallida var. purpurea (Trad-SH) à genotoxicidade e mutagenicidade induzidas por diferentes concentrações de NDEA (0,1; 0,5; 5 e 25mM) por 3h, por 3 dias consecutivos, incluindo controle negativo (água destilada) e controle positivo, hidrazida maleica (MH 30mg/mL). Depois do tratamento, as raízes foram hidrolizadas, esmagadas e o índice mitótico (IM) e anormalidades citológicas foram contadas. Os resultados revelaram um efeito citostático de NDEA (0,5 e 5mM), pela significante redução do IM. Chromosome stickiness sugere um efeito citotóxico de NDEA. T pallida purpurea não respondeu ao mutágeno com um padrão dose dependente. Em conclusão, nossos estudos indicaram que raízes de Allium cepa L. possue sensibilidade na detecção genotóxica de NDEA, mas não para o ensaio Trad-SH.

Estudio de genotoxicidad de Picrasma crenata (Vell.) Engl. - Simaroubaceae - / Genotoxicity study on Picrasma crenata (Vell.) Engl. - Simaroubaceae -

En la medicina popular se utiliza el leño de Picrasma crenata en infusión como pediculicida y como tónico amargo no astringente. Los principios activos responsables de la actividad son los quasinoides. Los objetivos de este trabajo son: determinar la actividad de las infusiones sobre el desarrollo de raíces y la división celular mediante el Test de Allium cepa; analizar la correlación de las concentraciones y los parámetros macro y microscópicos e interpretar la posible genotoxicidad de la infusión. Las concentraciones empleadas fueron 2,5 mg%; 5,0 mg%, 10,0 mg%, 20,0 mg% y 40,0 mg%. Se observó una correlación estadísticamente significativa de las concentraciones con las longitudes de las raíces y las anomalías macroscópicas; además, una correlación significativa de los índices mitóticos con las longitudes de las raíces y las anomalías microscópicas. Así, se puede inferir que los extractos en las concentraciones ensayadas podrían presentar actividad genotóxica.

Infusions of Picrasma crenata woods are used in folk medicine against lice and as a non astringent bitter tonic. The active principles responsible for the activity are the quasinoides. The objectives of this work are: to establish the activity of the infusions on the development by roots and the cellular division by means of the Test of Allium cepa; to analyze the correlation of the concentrations with macro and microscopic parameters and to conclude about the possible genotoxicity of the infusion. The used concentrations were 2.5 mg%; 5,0 mg%, 10,0 mg%, 20,0 mg% and 40,0 mg%. A statistically significant correlation between the concentrations and the roots lengths and macroscopic aberrations and a significant correlation between the mitotic index and the roots lengths and microscopic aberrations have been observed. Thus, it is possible to deduce that the extracts in the tested concentrations could present genotoxic activity.

Determination of vanadium accumulation in onion root cells (Allium cepa L) and its correlation with toxicity

The vanadium is a metal that presents great interest from the toxicological point of view, because of the numerous alterations that can take place in different biological systems. This work evaluated the capacity of vanadium accumulation and its correlation with genotoxic effects in root cells of Allium cepa L. The bulbs were cultivated in renovated filtered water each 24 h, at a temperature of 25 +/- 0.5 degrees C, in darkness and constant aeration. Treatments were carried out under the same experimental conditions, using water solutions of vanadium of 25, 50, 75 and 100 microg/g for 0, 12, 24, 48 and 72 h. A control was carried out where metal solution was substituted by distilled water. After the treatment, the meristems were fixed with alcohol--acetic acid (3:1) and stained according to the technique of Feulge n. The capacity of accumulation was determined by GFAAS. The analysis of the results revealed an accumulation of the metal for all times and concentrations. No correlation was presented among vanadium accumulation, growth and mitotic index; however, positive correlation was given with the induction of chromosomic aberrations. In conclusion, vanadium is able to induce cytotoxic effect in the exposed roots, but only genotoxic effect was correlated with metal accumulation.

Effects of Pterocaulon polystachyum DC. (Asteraceae) on onion (Allium cepa) root-tip cells

In Brazil leaf infusions of the plant Pterocaulon polystachyum DC (Asteraceae) are used to treat digestive problems. We used plants from six P. polystachyum populations to prepare fresh aqueous leaf infusions at the concentration normally used in Brazil (2.5 g L-1) and at twice (5 g L-1) and four times (10 g L-1) this concentration. We rooted onion bulbs in a water control or one of the infusions for 24 h and used the in vivo onion (Allium cepa) root-tip cell test to investigate the potential mutagenicity of the infusions by calculating the mitotic index for the control and the experimental treatments and comparing them using the Chi-squared test (chi2, p = 0.05). There was a highly significant decrease in the mitotic index of root-tip cells treated with infusion as compared to those exposed to water only. These results indicate that P. polystachyum infusions present cytotoxic and anti-proliferative activity and therefore have therapeutic potential.

Genotoxicity and mutagenicity of water contaminated with tannery effluents, as evaluated by the micronucleus test and comet assay using the fish Oreochromis niloticus and chromosome aberrations in onion root-tips

Cytotoxicity of metals is important because some metals are potential mutagens able to induce tumors in humans and experimental animals. Chromium can damage DNA in several ways, including DNA double strand breaks (DSBs) which generate chromosomal aberrations, micronucleus formation, sister chromatid exchange, formation of DNA adducts and alterations in DNA replication and transcription. In our study, water samples from three sites in the Córrego dos Bagres stream in the Franca municipality of the Brazilian state of São Paulo were subjected to the comet assay and micronucleus test using erythrocytes from the fish Oreochromis niloticus. Nuclear abnormalities of the erythrocytes included blebbed, notched and lobed nuclei, probably due to genotoxic chromium compounds. The greatest comet assay damage occurred with water from a chromium-containing tannery effluent discharge site, supporting the hypothesis that chromium residues can be genotoxic. The mutagenicity of the water samples was assessed using the onion root-tip cell assay, the most frequent chromosomal abnormalities observed being: c-metaphases, stick chromosome, chromosome breaks and losses, bridged anaphases, multipolar anaphases, and micronucleated and binucleated cells. Onion root-tip cell mutagenicity was highest for water samples containing the highest levels of chromium.

The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells

Root growth, G2 length, and the frequency of aberrant mitoses and apoptotic nuclei were recorded after a single X-ray irradiation, ranging from 2.5 to 40 Gy, in Allium cepa L. root meristematic cells. After 72 h of recovery, root growth was reduced in a dose-dependent manner from 10 to 40 Gy, but not at 2.5 or 5 Gy doses. Flow cytometry plus TUNEL (TdT-mediated dUTP nick end labeling) showed that activation of apoptosis occurred only after 20 and 40 Gy of X-rays. Nevertheless, irrespective of the radiation dose, conventional flow cytometry showed that cells accumulated in G2 (4C DNA content). Simultaneously, the mitotic index fell, though a mitotic wave appeared later. Cell accumulation in G2 was transient and partially reversed by caffeine, thus it was checkpoint-dependent. Strikingly, the additional G2 time provided by this checkpoint was never long enough to complete DNA repair. Then, in all cases, some G2 cells with still-unrepaired DNA underwent checkpoint adaptation, i.e., they entered into the late mitotic wave with chromatid breaks. These cells and those produced by the breakage of chromosomal bridges in anaphase will reach the G1 of the next cell cycle unrepaired, ensuring the appearance of genome instability.