RESUMEN
Historically, formaldehyde was used as a preservative in personal care products to extend product shelf-life; however, given its skin sensitization potential it has been phased out of use and replaced with formaldehyde-releasing preservatives, such as Dimethyloldimethyl hydantoin (DMDMH). A relationship has been established between positive patch test results following exposure to DMDMH and previous sensitization to formaldehyde. Upon direct contact with the skin, formaldehyde can react with skin proteins and cause an acute inflammatory reaction, which may progress to skin sensitization following repeated exposure. This quantitative risk assessment (QRA) aimed to assess the risk of skin sensitization induction following use of shampoo products containing the maximum allowable concentrations of DMDMH in formulation (1% w/v), translating to a free formaldehyde concentration of 0.02%. To determine a margin of safety (MOS) for exposure to DMDMH from use of shampoo products, consumer exposure levels (CEL) were estimated based on typical use scenarios and then benchmarked against an acceptable exposure level (AEL). The AEL was derived using a weight of evidence approach where a range of no expected sensitization induction levels (NESILs) was utilized. The MOS values for a shampoo product containing 1% DMDMH (.02% formaldehyde) was above 1 for the typical use scenario indicating a low likelihood of skin sensitization induction among healthy individuals. Thus, it can be concluded that shampoo products containing DMDMH at or below current allowable concentrations are not expected to increase the risk of skin sensitization induction.
Asunto(s)
Dermatitis Alérgica por Contacto , Hidantoínas , Humanos , Dermatitis Alérgica por Contacto/etiología , Hidantoínas/toxicidad , Formaldehído/toxicidad , Anticonvulsivantes , Conservadores Farmacéuticos/toxicidad , Medición de Riesgo/métodosRESUMEN
Rovral® is a fungicide used to control pests that affect various crops and little is known regarding its effects on embryonic development of amniotes. Thus, this study aimed to determine the influence of Rovral® during chicken organogenesis using acute in ovo contamination. Fertilized eggs were inoculated with different concentrations of Rovral® (100, 300, 500 or 750 µl/ml), injected into the egg's air chamber. After 7 days, embryos were examined for possible malformations, staging, weight and mortality. Subsequently, head, trunk, limbs and eyes were measured for morphometry and asymmetry. For blood analysis, eggs were treated with 300 µl/ml Rovral® and glucose, presence of micronuclei and erythrocyte nuclei abnormalities determined. Treatments with Rovral® affected the mortality rate in a concentration-dependent manner. LC50 value was found to be 596 µl/ml which represents 397-fold higher than the recommended concentration for use. Rovral® produced several malformations including hemorrhagic, ocular and cephalic abnormalities. No significant changes were observed in body weight, staging, body measurements, symmetry and glucose levels of live embryos, which indicates this fungicide presents low toxicity under the analyzed conditions. Changes in erythrocyte nuclei were noted; however significant difference was observed only for presence of binucleated erythrocytes. It is important to point out that possibly more significant changes may have occurred at lower concentrations through chronic contamination. Therefore, caution is needed in the use of this fungicide, since it presents teratogenic and mutagenic potential.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Embrión de Pollo/efectos de los fármacos , Embrión no Mamífero/efectos de los fármacos , Desarrollo Embrionario/efectos de los fármacos , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Aminoimidazol Carboxamida/toxicidad , Animales , Pollos , Relación Dosis-Respuesta a Droga , Dosificación Letal Mediana , Mutágenos/toxicidad , Teratógenos/toxicidadRESUMEN
This study concerns synthesis and evaluation of pharmacodynamic and pharmacokinetic profile for all four stereoisomers of MF-8 (5-(4-fluorophenyl)-3-(2-hydroxy-3-(4-(2-methoxyphenyl)piperazin-1-yl)propyl)-5-methylimidazolidine-2,4-dione), the previously described, highly potent 5-HT7R ligand with antidepressant activity on mice. The combination of DFT calculations of 1H NMR chemical shifts with docking and dynamic simulations, in comparison to experimental screening results, provided prediction of the configuration for one of two present stereogenic centers. The experimental data for stereoisomers (MF-8A-MF-8D) confirmed the significant impact of stereochemistry on both, 5-HT7R affinity and antagonistic action, with Ki and Kb values in the range of 3-366 nM and 0.024-99 µM, respectively. We also indicated the stereochemistry-dependent influence of the tested compounds on P-glycoprotein efflux, absorption in Caco-2 model, metabolic pathway as well as CYP3A4 and CYP2C9 activities.
Asunto(s)
Hidantoínas/farmacocinética , Piperazinas/farmacocinética , Antagonistas de la Serotonina/farmacocinética , Animales , Sitios de Unión , Línea Celular Tumoral , Citocromo P-450 CYP2C9/química , Citocromo P-450 CYP2C9/metabolismo , Inhibidores del Citocromo P-450 CYP3A/síntesis química , Inhibidores del Citocromo P-450 CYP3A/metabolismo , Inhibidores del Citocromo P-450 CYP3A/farmacocinética , Inhibidores del Citocromo P-450 CYP3A/toxicidad , Teoría Funcional de la Densidad , Estabilidad de Medicamentos , Humanos , Hidantoínas/síntesis química , Hidantoínas/metabolismo , Hidantoínas/toxicidad , Ratones , Microsomas Hepáticos/metabolismo , Modelos Químicos , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Piperazinas/síntesis química , Piperazinas/metabolismo , Piperazinas/toxicidad , Unión Proteica , Espectroscopía de Protones por Resonancia Magnética , Receptores de Serotonina/química , Receptores de Serotonina/metabolismo , Antagonistas de la Serotonina/síntesis química , Antagonistas de la Serotonina/metabolismo , Antagonistas de la Serotonina/toxicidad , EstereoisomerismoRESUMEN
The fungicide Iprodione is widely applied in vegetables and raises concern for human health. The A549 human lung carcinoma cell line is a suitable model for assessing the toxicological effects of drugs. The goal of this work was to evaluate the genotoxicity and oxidative stress in the A549 cell line exposed to sublethal concentrations from 3 to 100 µg/mL Iprodione considering LC50 = 243.4 µg/mL Iprodione, as determined by the MTT assay. Generalized Linear Mixed Models (GLMM) were performed to determine the association between the responses NDI, MNim and MNib and the explanatory variables. Iprodione and solvent were relativized to the control whereas the concentration was included as numeric variable. ANOVA was used for the comparison of treatments. The coefficients of linear association between the explanatory variables and NDI, and the coefficients of logistic association between explanatory variables and MNim were not significant. However, these coefficients showed significant association with MNib only for Iprodione treatment but not for Iprodione concentration, indicating lack of dose-response relationship. Genotoxicity risk assessment indicated that the increase in Iprodione concentrations increased slightly the probability of belonging to the genotoxic category. ANOVA showed significant differences in MNib, and non-significant differences in NDI and MNim among treatments. The oxidative stress analysis performed at 3, 12, and 25 µg/mL Iprodione showed a significant and linear increase in SOD, and a significant and linear decrease in GSH and GST. The Dunnett test was significant for GSH at 12 and SOD at 25 µg/mL.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Mutágenos/toxicidad , Estrés Oxidativo/efectos de los fármacos , Células A549 , Aminoimidazol Carboxamida/administración & dosificación , Aminoimidazol Carboxamida/toxicidad , Relación Dosis-Respuesta a Droga , Fungicidas Industriales/administración & dosificación , Humanos , Hidantoínas/administración & dosificación , Dosificación Letal Mediana , Neoplasias Pulmonares/metabolismo , Pruebas de Mutagenicidad , Mutágenos/administración & dosificación , Medición de Riesgo , Superóxido Dismutasa/metabolismoRESUMEN
Azoxystrobin (AZO) and Iprodione (IPR) fungicides are extensively used worldwide, and therefore, contaminate all environmental compartments. The toxicity and the mechanisms by which they affected immune cells are complex and remain unknown. This study investigated the impact of AZO and IPR on the in vitro function of mice peritoneal macrophages including lysosomal enzyme activity and tumor necrosis factor (TNF)α and nitric oxide (NO) production in response to lipopolysaccharide (LPS) stimulation, the proliferation of mice splenocytes stimulated by concanavalin (Con)A and LPS, and the production of the Th1cytokine interferon-gamma (IFNγ) and the Th2 cytokine interleukin (IL)-4 and IL-10 by ConA-activated splenocytes. This is the first report indicating that AZO and IPR fungicides dose-dependently inhibited mice macrophage lysosomal enzyme activity and LPS-stimulated production of TNFα and NO. Mitogen-induced proliferation of mice splenocytes was also suppressed by AZO and IPR in a dose-dependent manner. More pronounced impact was observed on ConA-induced response. The production of IFNγ by ConA-stimulated splenocytes was dose-dependently inhibited; however, the production of IL-4 and IL-10 increased in the same conditions. These results suggested that AZO and IPR polarized Th1/Th2 cytokine balance towards Th2 response. Overall, marked immunosuppressive effects were observed for AZO. The immunomodulatory effects caused by AZO and IPR were partially reversed by the pharmacological antioxidant N-acetylcysteine (NAC), suggesting that both fungicides exerted their actions through, at least in part, oxidative stress-dependent mechanism. Collectively, our data showed that AZO and IPR fungicides exerted potent immunomodulatory effects in vitro with eventually strong consequences on immune response and immunologically based diseases.
Asunto(s)
Acetilcisteína/farmacología , Aminoimidazol Carboxamida/análogos & derivados , Contaminantes Ambientales/toxicidad , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Macrófagos Peritoneales , Pirimidinas/toxicidad , Estrobilurinas/toxicidad , Aminoimidazol Carboxamida/toxicidad , Animales , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/inmunología , Células Cultivadas , Citocinas/biosíntesis , Relación Dosis-Respuesta a Droga , Macrófagos Peritoneales/efectos de los fármacos , Macrófagos Peritoneales/inmunología , Masculino , Ratones , Bazo/efectos de los fármacos , Bazo/inmunologíaRESUMEN
In this study, we selected and characterized different pesticide-tolerant bacteria isolated from a biomixture of a biopurification system that had received continuous applications of a pesticides mixture. The amplicon analysis of biomixture reported that the phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were predominant. Six strains grew in the presence of chlorpyrifos and iprodione. Biochemical characterization showed that all isolates were positive for esterase, acid phosphatase, among others, and they were identified as Pseudomonas, Rhodococcus and Achromobacter based on molecular and proteomic analysis. Bacterial growth decreased as both pesticide concentrations increased from 10 to 100 mg L-1 in liquid culture. The Achromobacter sp. strain C1 showed the best chlorpyrifos removal rate of 0.072-0.147 d-1 a half-life of 4.7-9.7 d and a maximum metabolite concentration of 2.10 mg L-1 at 120 h. On the other hand, Pseudomonas sp. strain C9 showed the highest iprodione removal rate of 0.100-0.193 d-1 a half-life of 4-7 d and maximum metabolite concentration of 0.95 mg L-1 at 48 h. The Achromobacter and Pseudomonas strains showed a good potential as chlorpyrifos and iprodione-degrading bacteria.
Asunto(s)
Achromobacter/metabolismo , Biodegradación Ambiental , Plaguicidas/metabolismo , Pseudomonas/metabolismo , Microbiología del Suelo , Achromobacter/aislamiento & purificación , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/metabolismo , Aminoimidazol Carboxamida/toxicidad , Cloropirifos/metabolismo , Cloropirifos/toxicidad , Hidantoínas/metabolismo , Hidantoínas/toxicidad , Plaguicidas/toxicidad , Pseudomonas/aislamiento & purificación , Contaminantes del Suelo/metabolismo , Contaminantes del Suelo/toxicidad , Recursos HídricosRESUMEN
In humans, bitter taste is mediated by 25 TAS2Rs. Many compounds, including certain active pharmaceutical ingredients, excipients, and nutraceuticals, impart their bitter taste (or in part) through TAS2R8 activation. However, effective TAS2R8 blockers that can either suppress or reduce the bitterness of these compounds have not been described. We are hereby reporting a series of novel 3-(pyrazol-4-yl) imidazolidine-2,4-diones as potent and selective TAS2R8 antagonists. In human sensory tests, S6821 and S7958, two of the most potent analogues from the series, demonstrated efficacy in blocking TAS2R8-mediated bitterness and were selected for development. Following data evaluation by expert panels of a number of national and multinational regulatory bodies, including the US, the EU, and Japan, S6821 and S7958 were approved as safe under conditions of intended use as bitter taste blockers.
Asunto(s)
Hidantoínas/farmacología , Pirazoles/farmacología , Receptores de Superficie Celular/antagonistas & inhibidores , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Gusto/efectos de los fármacos , Animales , Café/química , Descubrimiento de Drogas , Estabilidad de Medicamentos , Humanos , Hidantoínas/síntesis química , Hidantoínas/toxicidad , Estructura Molecular , Pirazoles/síntesis química , Pirazoles/toxicidad , Ratas , Relación Estructura-ActividadRESUMEN
The honey bee Apis mellifera is an important pollinator of agricultural crops and natural forests. Honey bee populations have declined over the years, as a result of diseases, pesticides, and management problems. Fungicides are the main pesticides found in pollen grains, which are the major source of protein for bees. The objective of this study was to evaluate the cytotoxic effects of the fungicide iprodione on midgut cells of adult A. mellifera workers. Bees were fed on iprodione (LD50, determined by the manufacturer) for 12 or 24 h, and the midgut was examined using light and transmission electron microscopies. The expression level of the autophagy gene atg1 was assessed in midgut digestive cells. Cells of treated bees had signs of apoptosis: cytoplasmic vacuolization, apical cell protrusions, nuclear fragmentation, and chromatin condensation. Ultrastructural analysis revealed some cells undergoing autophagy and necrosis. Expression of atg1 was similar between treated and control bees, which can be explained by the facts that digestive cells had autolysosomes, whereas ATG-1 is found in the initial phases of autophagy. Iprodione acts by inhibiting the synthesis of glutathione, leading to the generation of reactive oxygen species, which in turn can induce different types of cell death. The results indicate that iprodione must be used with caution because it has side effects on non-target organisms, such as pollinator bees.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Abejas/efectos de los fármacos , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Aminoimidazol Carboxamida/toxicidad , Animales , Apoptosis/efectos de los fármacos , Abejas/citología , Sistema Digestivo/citología , Sistema Digestivo/efectos de los fármacos , Plaguicidas/análisis , Polen/químicaRESUMEN
Having identified novel hydantoin derivatives (compounds 1-5) demonstrating promising photoprotective capacity against UV radiation, and understainding the problem of the biotic and abiotic degradation of UV filters, the aim of the study was to evaluate their metabolic fate with the environmental fungus Cunninghamella echinulata. In parallel, compound 1 in vitro microsomal metabolic pattern was evaluated. Finally, in silico toxicity of test compounds and their biotransformation products was estimated, and parent compounds photostability was assessed. The study demonstrated the capacity for C. echinulata to metabolize 1-5, which were biotransformed to a greater extent than the standard UV filter. O-dealkylation of the side chains attached to the phenyl or hydantoin rings, and hydroxylation of the phenyl ring occurred during microbial transformation. O-dealkylation product was a unique metabolite observed in microsomal biotransformation of 1, being its intrinsic clearance in the medium category range. In silico study demonstrated that compounds 1-5 have low toxicity risk. Among the resulting metabolites, four can increase the risk of reproductive effects as shown by OSIRIS prediction. Noteworthy, all indicated metabolites belong to minor metabolites, except for compound 3 major metabolite. Moreover, the results of the photostability study showed that 1-5 were considered to be photostable. To sum up, the obtained in vitro biotransformation, photostability, and in silico toxicity results encourage further studies on hydantoin derivatives as potential UV photoprotective agents. The presented biotransformation profile of compounds 1-5 by C. echinulata suggests that these compounds may follow a similar biodegradation fate when released into the environment.
Asunto(s)
Cunninghamella/metabolismo , Hidantoínas/metabolismo , Protectores Solares/metabolismo , Biodegradación Ambiental , Biotransformación , Hidantoínas/efectos de la radiación , Hidantoínas/toxicidad , Hidroxilación , Rayos UltravioletaRESUMEN
In this study the phytotoxic, cytotoxic, genotoxic and mutagenic effects of two commercial fungicide-active compounds, procymidone (PR) and iprodione (IP), were determined. The parameters evaluated were germination and root growth, mitotic index, chromosomal and nuclear aberrations, and molecular analyses were also performed in the model plant Allium cepa L. The results demonstrated that the active compounds PR and IP were phytotoxic, delaying germination and slowing the development of A. cepa seedlings. Moreover, PR and IP showed cytogenotoxicity towards A. cepa meristematic cells, inducing chromosomal changes and cell death. The mutagenic activity of the active compounds was demonstrated by the detection of DNA changes in simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) markers in the treated cells compared to the negative control. Together, these results contribute to a better understanding of the damage caused by these substances in living organisms and reveal a promising strategy for prospective studies of the toxic effects of environmental pollutants.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Compuestos Bicíclicos con Puentes/toxicidad , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Mutágenos/toxicidad , Cebollas/efectos de los fármacos , Aminoimidazol Carboxamida/toxicidad , Daño del ADN/efectos de los fármacos , Germinación/efectos de los fármacos , Meristema/efectos de los fármacos , Meristema/genética , Meristema/crecimiento & desarrollo , Cebollas/genética , Cebollas/crecimiento & desarrollo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Plantones/efectos de los fármacos , Plantones/genética , Plantones/crecimiento & desarrolloRESUMEN
Oocyte maturation can be a target of endocrine disruption by environmental chemicals capable of acting as hormone mimics, receptor blockers, and/or enzyme inhibitors. Six environmental chemicals (genistein, endosulfan, malathion, iprodione, carbaryl, and glyphosate) were selected to determine their ability to interfere with oocyte maturation in zebrafish. The translucent oocytes undergoing germinal vesicle (nucleus) breakdown (GVBD) were counted and expressed as a ratio of oocytes undergoing GVBD and total oocytes exposed. The GVBD increased significantly in oocytes exposed to 10â¯IU/ml to 100â¯IU/ml human chorionic gonadotropin (hCG). The lowest effective concentration of genistein that inhibited hCG-induced GVBD was 30⯵M, while endosulfan inhibited it at 0.03⯵M concentration. In addition, malathion inhibited hCG-induced GVBD at the lowest concentration of 60⯵M. These inhibitory effects were likely due to the chemicals acting as estrogen mimics, induction of estrogen receptors, or increase in aromatase activity resulting in enhanced estrogen action. Fungicide iprodione, possibly acting as a progestin mimic, promoted hCG-induced GVBD at the lowest concentration of 20⯵M, while the weed killer glyphosate inhibited hCG-induced GVBD starting at the 50⯵M concentration. These results demonstrate the feasibility of using fully grown zebrafish oocytes arrested at the prophase I stage in an in vitro incubation system to evaluate the effects of a variety of environmental chemicals on oocyte maturation.
Asunto(s)
Contaminantes Ambientales/toxicidad , Oocitos/efectos de los fármacos , Pruebas de Toxicidad/métodos , Pez Cebra , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/toxicidad , Animales , Diferenciación Celular/efectos de los fármacos , Gonadotropina Coriónica/toxicidad , Endosulfano/toxicidad , Femenino , Genisteína/toxicidad , Glicina/análogos & derivados , Glicina/toxicidad , Hidantoínas/toxicidad , Malatión/toxicidad , Plaguicidas/toxicidad , GlifosatoRESUMEN
A semifield study to assess the effects of iprodione on honeybees at label use rates was conducted on a bloom mustard crop. The present study followed the Organisation for Economic Co-operation and Development guideline 75 tunnel test and consisted of 3 groups: the iprodione-treated group, the untreated control group, and the toxic reference item group. In addition to the tunnels used for biological assessments, a tunnel was set up in the treatment and control groups to determine the level of residues in flowers, nectar, and pollen. The major endpoints to assess the effects of the application of iprodione were mortality, flight intensity, behavior, condition of the colonies, and development of the brood. Residue analysis showed that honeybees were exposed to significant residues of iprodione. However, no adverse effects were observed on overall mortality, flight intensity, behavior, or brood development of honeybees compared to control. It is concluded that iprodione does not adversely affect the health of honeybees when applied in agriculture at commercially relevant rates in a worst-case exposure scenario. Environ Toxicol Chem 2018;37:3086-3094. © 2018 SETAC.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Abejas/crecimiento & desarrollo , Conducta Animal/efectos de los fármacos , Flores/fisiología , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Planta de la Mostaza/fisiología , Hojas de la Planta/efectos de los fármacos , Aminoimidazol Carboxamida/toxicidad , Animales , Abejas/efectos de los fármacos , Vuelo Animal/efectos de los fármacos , Planta de la Mostaza/efectos de los fármacos , Néctar de las Plantas/química , Polen/química , Análisis de SupervivenciaRESUMEN
Pesticides are being used globally to improve agricultural production. They are applied specifically to combat with pathogens that are a major threat for reduced optimum yield of crops. This study was carried out to see the effect of commercially used pesticides on a specific plant protein viz. phytocystatin isolated from yellow mustard seeds (YMP). Phytocystatin is a thiol proteinase inhibitor, which regulates endogenous and exogenous cysteine proteinases and plays a vital physiological role in plants. Different classes of pesticides like fungicide (iprodione) of dicarboximide class and an insecticide (malathion) of class organophosphate are retorted for our study. In the presence of these pesticides, biophysical and biochemical changes were observed in phytocystatin. These changes were evaluated making use of caseinolytic activity assay, UV-vis spectroscopy, fluorescence spectroscopy, FTIR, and circular dichroism. Isothermal titration calorimetry was employed to see interaction pattern of these pesticides with phytocystatin. The results obtained clearly depict that the pesticides bind with the phytocystatin thereby changing its native conformation and reducing its intrinsic property of inhibition on cysteine proteinase as evident by reduced anti-papain inhibition in the presence of pesticides. Furthermore, CD and FTIR spectroscopy results clearly show a decrease in α-helical content upon interaction with malathion and iprodione. Among the two pesticides, iprodione has far more pronounced effect on YMP evident from striking changes in UV, Fluorescence, CD and FTIR spectroscopy. 2,4-dinitrophenylhydrazine spectrophotometric assay was also carried out to check production of ROS, generation of ROS was observed in the presence of these pesticides thus implying that ROS might be responsible for changes in native structure of phytocystatin induced by pesticides.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Cistatinas/metabolismo , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Insecticidas/toxicidad , Malatión/toxicidad , Planta de la Mostaza/efectos de los fármacos , Proteínas de Plantas/metabolismo , Inhibidores de Proteasas/metabolismo , Aminoimidazol Carboxamida/toxicidad , Cistatinas/química , Planta de la Mostaza/metabolismo , Inhibidores de Proteasas/química , Conformación Proteica/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Semillas , Análisis Espectral/métodos , Compuestos de Sulfhidrilo/metabolismoRESUMEN
It has been shown that non-cytotoxic doses of Carbendazim (CBZ), a broad-spectrum benzimidazole fungicide, possess endocrine-disrupting (androgen-like) actions, ex vivo, on the pubertal rat seminiferous epithelium. Iprodione (IPR), a dicarboximide fungicide, is also known to be an endocrine-disrupter (anti-androgen). The effect of a mixture of these two pesticides was investigated in the validated rat seminiferous tubule culture model. Cultures were performed in the absence or presence of CBZ 50nM or IPR 50nM either alone or in mixture (Mix), over a 3-week period. Mix exerted a dramatic effect on two proteins (Connexin 43 and Claudin-11) of the blood-testis barrier and possessed similar effects to IPR on some germ cell populations. The presence of IPR together with CBZ (Mix) cancelled the effect of CBZ on the increase of the androgen-dependent TP1 and TP2 mRNAs and on the decrease of ERα, ERß mRNAs. Nevertheless, CBZ alone or IPR alone or Mix induced toxicity on spermatogenesis resulting in a decrease of round spermatids (the precursors of spermatozoa). These results strongly suggest that, even at these low concentrations, the effects of IPR and of CBZ are not solely dependent on their respective anti-androgenic and androgen-like effects and should involve several mechanisms of action.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Bencimidazoles/toxicidad , Carbamatos/toxicidad , Disruptores Endocrinos/toxicidad , Fungicidas Industriales/toxicidad , Hidantoínas/toxicidad , Epitelio Seminífero/efectos de los fármacos , Aminoimidazol Carboxamida/toxicidad , Animales , Barrera Hematotesticular/efectos de los fármacos , Células Cultivadas , Claudinas/biosíntesis , Claudinas/genética , Conexina 43/biosíntesis , Conexina 43/genética , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Ratas , Ratas Sprague-Dawley , Maduración Sexual , Espermatocitos/efectos de los fármacos , Espermatogénesis/efectos de los fármacosRESUMEN
The use of biopurification systems can mitigate the effects of pesticide contamination on farms. The primary aim of this study was to evaluate the effect of pesticide dissipation on microbial communities in a pilot biopurification system. The pesticide dissipation of atrazine, chlorpyrifos and iprodione (35 mg kg-1 active ingredient [a.i.]) and biological activity were determined for 40 days. The microbial communities (bacteria, actinomycetes and fungi) were analyzed using denaturing gradient gel electrophoresis (DGGE). In general, pesticide dissipation was the highest by day 5 and reached 95%. The pesticides did not affect biological activity during the experiment. The structure of the actinomycete and bacterial communities in the rhizosphere was more stable during the evaluation than that in the communities in the control without pesticides. The rhizosphere fungal communities, detected using DGGE, showed small and transitory shifts with time. To conclude, rhizosphere microbial communities were not affected during pesticide dissipation in a pilot biopurification system.
Asunto(s)
Bacterias/efectos de los fármacos , Hongos/efectos de los fármacos , Consorcios Microbianos/efectos de los fármacos , Plaguicidas/toxicidad , Eliminación de Residuos Líquidos/métodos , Actinomyces/efectos de los fármacos , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/análisis , Aminoimidazol Carboxamida/toxicidad , Atrazina/análisis , Atrazina/toxicidad , Biodiversidad , Cloropirifos/análisis , Cloropirifos/toxicidad , Electroforesis en Gel de Gradiente Desnaturalizante , Hidantoínas/análisis , Hidantoínas/toxicidad , Plaguicidas/análisisRESUMEN
There is a current tendency to develop and apply environmentally friendly techniques that meet the requirements of green analytical chemistry as an alternative to conventional analytical methods. For toxicity evaluation, these alternatives may be found in bioassays such as Tradescantia. This technique, developed in the 1980s, is highly sensitive to evaluate environmental mutagens, simple and cheap. In this paper, the sensibility of both the Tradescantia micronucleus bioassay (Trad-MCN) and the Tradescantia stamen hair bioassay (Trad-SH) were studied for carbaryl, dimethoate and iprodione, common agricultural and domestic pesticides that are currently used in Chile, which have never been tested with such bioassays. Biomonitor exposures were performed by capillary absorption for each individual pesticide over a wide range of concentrations, from maximum residue limits (trace levels) up to the application dose in agricultural fields. In addition, the organochloride 4,4'-DDE was included but only in the concentration range from 0.01mgL-1 to 1mgL-1, mimicking residue concentrations since it is not a commercial product but, rather, the main breakdown product of the persistent organochloride pesticide 4,4-DDT, whose use was discontinued in Chile in the 1980s. The Trad-MCN bioassay revealed a significant increase in micronucleus frequency at the early tetrads of meiotic pollen mother cells of the biomonitor Tradescantia pallida var. purpurea, induced by 4,4'-DDE (for 1mgL-1), dimethoate (for 40mgL-1, 200mgL-1, 400mg/L-1) and carbaryl (for 889mgL-1). Iprodione did not generate any significant change at the tested concentration. Meanwhile, the Trad-SH bioassay was carried out by analysis of the phenotype variations of the stamen hair cells of the Tradescantia clone KU-20 for the same pesticides and doses. This bioassay was not sufficiently sensitive for toxicity evaluation of most of the pesticides tested, with exception of dimethoate in low doses (2 and 5mg/L-1).
Asunto(s)
Monitoreo del Ambiente , Plaguicidas/toxicidad , Tradescantia/efectos de los fármacos , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/toxicidad , Carbaril/toxicidad , Chile , Diclorodifenil Dicloroetileno , Dimetoato/toxicidad , Hidantoínas/toxicidad , Pruebas de Micronúcleos , Mutágenos , Tradescantia/genéticaRESUMEN
To measure the testicular toxicity of two fungicides (carbendazim and iprodione), alone or in a mixture, we used a rat ex vivo model of seminiferous tubules, greatly reducing the number of rodents used, in accordance with the 3R rule (Replacement, Reduction, and Refinement). This model allows the representation of puberty, a critical life period with regard to endocrine disruptors. The cellular modifications were followed for three weeks through transcriptomic and proteomic profiling analysis. A quantitative and comparative method was developed to estimate how known pathways were disturbed by each substance. This pathway-driven analysis revealed a strong alteration of steroidogenesis and an impairment of meiosis in all cases, albeit the initial molecular events were different for both substances. The ex vivo cytogenetic analysis confirmed that both fungicides alter the course of the first meiotic prophase. In addition, the mixture of both substances triggered effects greater than the sum of their cumulative effects and compromised future sperm motility after a shorter time of exposure compared with the fungicides tested separately. The alliance of an ex vivo culture with "omics" strategies complemented with a physiological examination is a powerful combination of tools for testing substances, separately or in a mixture, for their testicular toxicity. In particular, proteomics allowed the identification of systematically differentially expressed proteins in the secretomes of exposed cultures, such as FUCO and PEBP1, two proteins linked with the motility and fertilizing ability of spermatozoa, respectively. These proteins may be potential biomarkers of testicular dysfunction and infertility.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Alternativas a las Pruebas en Animales/métodos , Bencimidazoles/toxicidad , Carbamatos/toxicidad , Hidantoínas/toxicidad , Túbulos Seminíferos/efectos de los fármacos , Enfermedades Testiculares/inducido químicamente , Pruebas de Toxicidad/métodos , Aminoimidazol Carboxamida/toxicidad , Animales , Fungicidas Industriales/toxicidad , Masculino , Meiosis/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Túbulos Seminíferos/citología , Túbulos Seminíferos/metabolismo , Aberraciones Cromosómicas Sexuales/efectos de los fármacos , Espermatogénesis/efectos de los fármacos , Esteroides/biosíntesis , Técnicas de Cultivo de TejidosRESUMEN
There is a growing body of empirical evidence showing that wild and managed bees are negatively impacted by various pesticides that are applied in agroecosystems around the world. The lethal and sublethal effects of two widely used fungicides and one adjuvant were assessed in cage studies in California on blue orchard bees, Osmia lignaria, and in cage studies in Utah on alfalfa leafcutting bees, Megachile rotundata. The fungicides tested were Rovral 4F (iprodione) and Pristine (mixture of pyraclostrobin + boscalid), and the adjuvant tested was N-90, a non-ionic wetting agent (90% polyethoxylated nonylphenol) added to certain tank mixtures of fungicides to improve the distribution and contact of sprays to plants. In separate trials, we erected screened cages and released 20 paint-marked females plus 30-50 males per cage to document the behavior of nesting bees under treated and control conditions. For all females in each cage, we recorded pollen-collecting trip times, nest substrate-collecting trip times (i.e., mud for O. lignaria and cut leaf pieces for M. rotundata), cell production rate, and the number of attempts each female made to enter her own or to enter other nest entrances upon returning from a foraging trip. No lethal effects of treatments were observed on adults, nor were there effects on time spent foraging for pollen and nest substrates and on cell production rate. However, Rovral 4F, Pristine, and N-90 disrupted the nest recognition abilities of O. lignaria females. Pristine, N-90, and Pristine + N-90 disrupted nest recognition ability of M. rotundata females. Electroantennogram responses of antennae of O. lignaria females maintained in the laboratory did not differ significantly between the fungicide-exposed and control bees. Our results provide the first empirical evidence that two commonly used fungicides and a non-ionic adjuvant can disrupt nest recognition in two managed solitary bee species.
Asunto(s)
Fungicidas Industriales/toxicidad , Himenópteros/efectos de los fármacos , Himenópteros/fisiología , Comportamiento de Nidificación/efectos de los fármacos , Fenoles/toxicidad , Agentes Mojantes/toxicidad , Agricultura , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/toxicidad , Animales , Compuestos de Bifenilo/toxicidad , California , Carbamatos/toxicidad , Femenino , Hidantoínas/toxicidad , Masculino , Niacinamida/análogos & derivados , Niacinamida/toxicidad , Pirazoles/toxicidad , Estrobilurinas , UtahRESUMEN
Guanine (G) is a target for oxidation by reactive oxygen species in DNA, RNA, and the nucleotide pool. Damage to DNA yields products with alternative properties toward DNA processing enzymes compared to those of the parent nucleotide. A new lesion, 5-carboxamido-5-formamido-2-iminohydantoin (2Ih), bearing a stereocenter in the base was recently identified from the oxidation of G. DNA polymerase and base excision repair processing of this new lesion has now been evaluated. Single nucleotide insertion opposite (S)-2Ih and (R)-2Ih in the template strand catalyzed by the DNA polymerases Klenow fragment exo(-), DPO4, and Hemo KlenTaq demonstrates these lesions to cause point mutations. Specifically, they promote 3-fold more G·C â C·G transversion mutations than G·C â T·A, and (S)-2Ih was 2-fold more blocking for polymerase bypass than (R)-2Ih. Both diastereomer lesions were found to be substrates for the DNA glycosylases NEIL1 and Fpg, and poorly excised by endonuclease III (Nth). The activity was independent of the base pair partner. Thermal melting, CD spectroscopy, and density functional theory geometric optimization calculations were conducted to provide insight into these polymerase and DNA glycosylase studies. These results identify that formation of the 2Ih lesions in a cell would be mutagenic in the event that they were not properly repaired.
Asunto(s)
Reparación del ADN , ADN Polimerasa Dirigida por ADN/metabolismo , Guanina/metabolismo , Hidantoínas/toxicidad , Mutación , Dicroismo Circular , Oxidación-Reducción , Especificidad por SustratoRESUMEN
Nitrofurans are antimicrobial compounds containing a nitro group at the 5-position of the furan ring and an amine or hydrazide side chain derivative. One member of the nitrofurans, nitrofurantoin (NFT), is a renal carcinogen in male rats despite its still controversial genotoxicity. We investigated chemical structure-related modes of action of NFT, and reporter gene mutation assays for NFT and its constituent moieties were performed. NFT, 5-nitro-2-furaldehyde (NFA), or 1-aminohydantoin (AHD) was administered to male F344 gpt delta rats by gavage for 4 or 13 weeks at a carcinogenic or the maximum tolerated dose. NFT caused a significant increase in gpt mutant frequency (MF) at 13 weeks with G-base substitution mutations. An increase in gpt MF was also observed in the NFA-treated group at 13 weeks, but not in the AHD-treated group. 8-Hydroxydeoxyguanosine (8-OHdG) levels in the kidney DNA of NFT-treated rats were significantly increased after 4 weeks. NFT caused accumulation of hyaline droplets indicated by positive immunostaining and western blot analysis for α2u-globulin in the proximal tubules. An additional study, in which female gpt delta rats were given NFT at the same dose used for males, was performed to mitigate the effect of α2u-globulin. NFT exerted the same effects on female rat kidneys to the same extent as males in terms of gpt MF and 8-OHdG level. Thus, it is highly probable that the structure of the nitro furan plays a key role in NFT-induced genotoxicity and genotoxic mechanisms including oxidative DNA damage are involved in NFT-induced renal carcinogenesis. α2u-globulin-mediated nephropathy may be a prerequisite for NFT-induced renal carcinogenesis in male rats, and additionally NFT could be a latent carcinogen in female rats and other animal species.