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1.
Int J Mol Sci ; 23(12)2022 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-35743241

RESUMO

Many years have passed since micronuclei were first observed then accepted as an indicator of the effect of mutagens. However, the possible mechanisms of their formation and elimination from the cell are still not fully understood. Various stresses, including mutagens, can alter gene expression through changes in DNA methylation in plants. In this study we demonstrate for the first time DNA methylation in the foci of 5S and 35S rDNA sequences in individual Brachypodium distachyon micronuclei that are induced by mutagenic treatment with maleic acid hydrazide (MH). The impact of MH on global epigenetic modifications in nuclei and micronuclei has been studied in plants before; however, no in situ analyses of DNA methylation in specific DNA sequence sites are known. To address this problem, we used sequential immunodetection of 5-methylcytosine and fluorescence in situ hybridization (FISH) with 5S and 25S rDNA probes on the non-dividing cells of B. distachyon. Such investigations into the presence or absence of DNA methylation within specific DNA sequences are extremely important in plant mutagenesis in the light of altering gene expression.


Assuntos
Brachypodium , Hidrazida Maleica , Brachypodium/genética , Cromossomos de Plantas , Metilação de DNA , DNA de Plantas/genética , DNA Ribossômico/genética , Hibridização in Situ Fluorescente , Hidrazida Maleica/farmacologia , Mutagênicos/toxicidade , Plantas/genética
2.
Pesqui. bras. odontopediatria clín. integr ; 22: e210058, 2022. tab, graf
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1365226

RESUMO

ABSTRACT Objective To evaluate and compare the effect of 17% Ethylenediaminetetraacetic Acid (EDTA), 9% Etidronic acid (HEDP), and 7% Maleic acid (MA) on the push-out bond strength of NeoMTA Plus sealer to the coronal, middle, and apical thirds of root canal dentin. Material and Methods Forty single-rooted human maxillary central incisors were selected and decoronated to 12 mm long root fragments. Working length was established and root canals were then enlarged up to rotary Protaper F3. After each instrumentation, the root canal was irrigated with 2.5% NaOCl. For the final irrigation regimen, the specimens were divided into 4 groups (n=10) and treated with EDTA, HEDP, MA or Saline. Root canals were coated with NeoMTA Plus sealer, and obturation was done with single cone obturation technique. Subsequently, three horizontal sections were taken from the coronal, middle and apical thirds of each specimen, and POBS was measured using a universal testing machine. The type of bond failures was assessed under a stereomicroscope. Statistical analysis was done with One-way ANOVA with Tukey's Post hoc analysis. Results MA and EDTA showed the highest POBS. There was no significant difference in bond strength between MA and EDTA (p>0.05). HEDP and Saline showed lower POBS. Among all the four groups, the coronal third showed the highest values, followed by middle and apical thirds. Conclusion The type of chelating agent used during the root canal treatment significantly affects the bond strength of NeoMTA Plus to the root canal dentin.


Assuntos
Humanos , Materiais Restauradores do Canal Radicular , Resistência à Tração , Quelantes/química , Cimentos Dentários , Endodontia , Análise de Variância , Ácido Edético , Ácido Etidrônico , Materiais Dentários/química , Incisivo , Índia , Hidrazida Maleica
3.
Anal Methods ; 13(39): 4662-4673, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34546231

RESUMO

A simple electrochemical sensing platform based on a low-cost disposable laser-induced porous graphene (LIPG) flexible electrode for the intelligent analysis of maleic hydrazide (MH) in potatoes and peanuts coupled with machine learning (ML) was successfully designed. The LIPG electrode was patterned by a simple one-step laser-induced procedure on commercial polyimide film using a computer-controlled direct laser writing micromachining system and displayed excellent flexibility, 3D porous structure, large specific surface area, and preferable conductivity. A data partitioning technique was proposed for the optimal MH concentration ranges by selecting the size of datasets, including the size of the training set and the size of the test set combined with the performance metrics of ML models. Different algorithms such as artificial neural networks (ANN), random forest (RF), and least squares support vector machine (LS-SVM) were selected to build the ML models. Three ML models were evaluated, and the LS-SVM model displayed unique superiority. Both the recoveries and RSD of practical application were further measured to assess the feasibility of the selected LS-SVM model. This will have important theoretical and practical significance for the intelligent analysis of harmful residuals in agro-product safety using an electrochemical sensing platform.


Assuntos
Hidrazida Maleica , Análise dos Mínimos Quadrados , Aprendizado de Máquina , Redes Neurais de Computação , Máquina de Vetores de Suporte
4.
Int J Mol Sci ; 21(22)2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33198069

RESUMO

ATR, a DNA damage signaling kinase, is required for cell cycle checkpoint regulation and detecting DNA damage caused by genotoxic factors including Al3+ ions. We analyzed the function of the HvATR gene in response to chemical clastogen-maleic acid hydrazide (MH). For this purpose, the Al-tolerant barley TILLING mutant hvatr.g was used. We described the effects of MH on the nuclear genome of hvatr.g mutant and its WT parent cv. "Sebastian", showing that the genotoxic effect measured by TUNEL test and frequency of cells with micronuclei was much stronger in hvatr.g than in WT. MH caused a significant decrease in the mitotic activity of root cells in both genotypes, however this effect was significantly stronger in "Sebastian". The impact of MH on the roots cell cycle, analyzed using flow cytometry, showed no differences between the mutant and WT.


Assuntos
Alumínio/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Dano ao DNA/efeitos dos fármacos , Hordeum/efeitos dos fármacos , Hidrazida Maleica/farmacologia , Proteínas de Arabidopsis/metabolismo , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/genética , Dano ao DNA/genética , Genoma de Planta/efeitos dos fármacos , Genoma de Planta/genética , Genótipo , Hordeum/genética , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Mutagênicos/farmacologia , Mutação/efeitos dos fármacos , Mutação/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética
5.
Planta ; 252(4): 64, 2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-32968874

RESUMO

MAIN CONCLUSION: Transcriptomic analysis revealed maleic hydrazide suppresses apical and axillary bud development by altering the expression of genes related to meristem development, cell division, DNA replication, DNA damage and recombination, and phytohormone signaling. Topping (removal of apical buds) is a common agricultural practice for some crop plants including cotton, cannabis, and tobacco. Maleic hydrazide (MH) is a systemic suckercide, a chemical that inhibits shoot bud growth, used to control the growth of apical (ApB) and axillary buds (AxB) following topping. However, the influence of MH on gene expression and the underlying molecular mechanism of controlling meristem development are not well studied. Our RNA sequencing analysis showed that MH significantly influences the transcriptomic landscape in ApB and AxB of chemically topped tobacco. Gene ontology (GO) enrichment analysis revealed that upregulated genes in ApB were enriched for phosphorelay signal transduction, and the regulation of transition timing from vegetative to reproductive phase, whereas downregulated genes were largely associated with meristem maintenance, cytokinin metabolism, cell wall synthesis, photosynthesis, and DNA metabolism. In MH-treated AxB, GO terms related to defense response and oxylipin metabolism were overrepresented in upregulated genes. GO terms associated with cell cycle, DNA metabolism, and cytokinin metabolism were enriched in downregulated genes. Expression of KNOX and MADS transcription factor (TF) family genes, known to be involved in meristem development, were affected in ApB and AxB by MH treatment. The promoters of MH-responsive genes are enriched for several known cis-acting elements, suggesting the involvement of a subset of TF families. Our findings suggest that MH affects shoot bud development in chemically topped tobacco by altering the expression of genes related to meristem development, DNA repair and recombination, cell division, and phytohormone signaling.


Assuntos
Regulação da Expressão Gênica de Plantas , Hidrazida Maleica , Brotos de Planta , Tabaco , Transcriptoma , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Hidrazida Maleica/farmacologia , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/genética , Tabaco/efeitos dos fármacos , Tabaco/genética , Transcriptoma/efeitos dos fármacos
6.
J Sep Sci ; 42(14): 2390-2397, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31038270

RESUMO

Maleic hydrazide has been extensively used as an effective growth regulator in tobacco sucker control. After application, maleic hydrazide distributes itself throughout the tobacco plant where it can exist as free, or forms glucoside conjugates with glucose, or becomes bound with lignin. Among them, free maleic hydrazide and its glucoside conjugates are extractable under conventional solvent extraction, while lignin bound maleic hydrazide is claimed to be non-extractable. Herein, an autoclave extraction method has been developed to extract maleic hydrazide effectively, in which tobacco samples are extracted in an autoclave at 130°C for 1 h using 4 M hydrochloric acid. Under such pressurized hot acidic water conditions, lignin bound maleic hydrazide can be released. Meanwhile, glucoside conjugates are hydrolyzed. Total maleic hydrazide is detected by liquid chromatography coupled with tandem mass spectrometry, and the quantitative results coincide well with that obtained from the international standard method. The proposed autoclave extraction with liquid chromatography and tandem mass spectrometry method exhibits excellent linearity in the range of 5-200 mg/kg (R2  = 0.9998), the matrix matched limit of detection and limit of quantification is 0.68 and 2.27 mg/kg, respectively. This method is simple and improves sample capacity, providing an effective approach to monitoring maleic hydrazide residues in tobacco.


Assuntos
Hidrazida Maleica/análise , Resíduos de Praguicidas/análise , Tabaco/química , Cromatografia Líquida , Espectrometria de Massas em Tandem
7.
Se Pu ; 36(7): 651-658, 2018 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-30136537

RESUMO

A hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method was established for the simultaneous determination of maleic hydrazide (MH) and its two glucosides in tobacco leaves. Ultrasonic assisted extraction of MH and its glucosides was performed using acetonitrile-methyl tert-butyl ether-water (7:10:13, volume ratio). The extraction solution was then centrifuged, and the subnatant was transferred for solvent replacement using acetonitrile. The extract in acetonitrile was then analyzed using HILIC-MS/MS. Method validation was performed, and the linear ranges for MH and MH-O-ß -D-glucoside were 5-150 mg/kg with correlation coefficients (r2) greater than 0.9971 for matrix-matched calibration curves. Limits of detection for MH and MH-O-ß -D-glucoside were 0.5 mg/kg and 0.3 mg/kg, and limits of quantification were 1.0 mg/kg and 0.8 mg/kg, respectively. The recoveries were in the range of 83.1%-112.3% at three spiked levels (10, 40, 80 mg/kg), with intra-day repeatability of 2.7% and 3.8%, inter-day repeatability of 8.3% and 7.1% at 40 mg/kg. The established method was used for the study of MH metabolism in tobacco leaves. By the 28th day after MH spraying, the content of MH in tobacco leaves had decreased by 80.8%, of which only 7.6% transformed to MH-glucosides. The disposition of the remainder needs to be studied.


Assuntos
Glucosídeos/análise , Hidrazida Maleica/análise , Folhas de Planta/química , Tabaco/química , Calibragem , Cromatografia Líquida , Interações Hidrofóbicas e Hidrofílicas , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
8.
Ann Bot ; 122(7): 1161-1171, 2018 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-29982446

RESUMO

Background and Aims: Brachypodium distachyon (Brachypodium) is a model species for temperate cereals and other economically important grasses. Its favourable cytogenetic features and advanced molecular infrastructure make it a good model for understanding the mechanisms of instability of plant genomes after mutagenic treatment. The aim of this study was to qualitatively and quantitatively assess the composition and origin of micronuclei arising from genomic fracture, and to detect possible 'hot spots' for mutagen-induced DNA breaks. Methods: Seeds of Brachypodium were treated with maleic hydrazide (MH) or X-rays. The structure of mutagen-induced micronuclei was analysed in root-tip meristematic cells using multicolour fluorescence in situ hybridization (mcFISH) with various repetitive (5S rDNA, 25S rDNA, telomeric, centromeric) and low-repeat [small and large pools of bacterial artificial chromosome (BAC) clones specific for chromosome Bd1] DNA sequences. Key Results: The majority of micronuclei derive from large, acentric fragments. X-rays caused more interstitial DNA breaks than MH. Double-strand breaks rarely occurred in distal chromosome regions. Bd1 contributed to the formation of more mutagen-induced micronuclei than expected from random chromosome involvement. Conclusions: mcFISH with chromosome-specific BAC clones offers insight into micronuclei composition, in so far as it allows their origin and formation to be determined more specifically. A reliable assay for micronuclei composition is crucial for the development of modern genotoxicity tests using plant cells. The combination of mutagenic treatments and well-developed cytomolecular resources in Brachypodium make this model species very promising for plant mutagenesis research.


Assuntos
Brachypodium/genética , Cromossomos de Plantas/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico , Mutagênicos/efeitos adversos , Brachypodium/efeitos dos fármacos , Coloração Cromossômica , Cromossomos de Plantas/genética , Quebras de DNA , Hibridização in Situ Fluorescente , Hidrazida Maleica/efeitos adversos , Raios X/efeitos adversos
9.
Plant Physiol Biochem ; 130: 314-323, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30036860

RESUMO

The aim of the present study was to evaluate the antigenotoxic potential of P. aculeata L. leaf extract/fractions against maleic hydrazide (MH) using Allium cepa root chromosomal aberration assay. The excessive reduction in root growth and mitotic index value was observed after 3 h treatment of MH as compared to negative control (water). In case of MH treatment, frequency of aberrated cells significantly (p ≤ 0.05) raised from 129 to 337 at 0.1 ppm and 2.0 ppm concentrations respectively. From root growth inhibition test with MH treatment, EC50 value i.e. 0.5 ppm was selected to study the antigenotoxic effect of different extract/fractions of P. aculeata L. leaves. All the extract/fractions showed increase in mitotic index and great reduction in chromosomal aberrations with rise in concentration against the genotoxicity of MH. Among all the extract/fractions, butanol and ethyl acetate fractions showed significant reduction in chromosomal aberrations in A. cepa cells and indicates the chemo preventive activity. Antigenotoxic property of this plant is due to the presence of various phytochemicals in leaf such as epi-orientin, Parkinsonin-A, Parkinsonin-B, orientin, iso-orientin, vitexin, iso-vitexin, C-glycosylflavone, parkintin, rotenoids, terpenoids, flavonoids, saponins, alkaloids, glycosides and anthraquinone etc. Our result showed that among all the treatments, simultaneous treatment showed best result followed by pre and post treatment. Further studies in animal model are suggested for further evaluation of the use of P. aculeata leaf extract in human welfare.


Assuntos
Aberrações Cromossômicas/efeitos dos fármacos , Fabaceae/química , Cebolas/efeitos dos fármacos , Extratos Vegetais/farmacologia , Folhas de Planta/química , Hidrazida Maleica/antagonistas & inibidores , Hidrazida Maleica/toxicidade , Índice Mitótico , Testes de Mutagenicidade , Cebolas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento
10.
J Agric Food Chem ; 65(34): 7535-7541, 2017 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-28759225

RESUMO

A simple high-throughput liquid chromatography/tandem mass spectrometry (LC-MS-MS) method was developed for the determination of maleic hydrazide, glyphosate, fosetyl aluminum, and ethephon in grapes using a reversed-phase column with weak anion-exchange and cation-exchange mixed mode. A 5 g test portion was shaken with 50 mM HOAc and 10 mM Na2EDTA in 1/3 (v/v) MeOH/H2O for 10 min. After centrifugation, the extract was passed through an Oasis HLB cartridge to retain suspended particulates and nonpolar interferences. The final solution was injected and directly analyzed in 17 min by LC-MS-MS. Two MS-MS transitions were monitored in the method for each target compound to achieve true positive identification. Four isotopically labeled internal standards corresponding to each analyte were used to correct for matrix suppression effects and/or instrument signal drift. The linearity of the detector response was demonstrated in the range from 10 to 1000 ng/mL for each analyte with a coefficient of determination (R2) of ≥0.995. The average recovery for all analytes at 100, 500, and 2000 ng/g (n = 5) ranged from 87 to 111%, with a relative standard deviation of less than 17%. The estimated LOQs for maleic hydrazide, glyphosate, fosetyl-Al, and ethephon were 38, 19, 29, and 34 ng/g, respectively.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Herbicidas/análise , Hidrazida Maleica/análise , Compostos Organofosforados/análise , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Vitis/química , Contaminação de Alimentos/análise , Glicina/análogos & derivados , Glicina/análise
11.
PLoS One ; 12(1): e0170618, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28118403

RESUMO

Brachypodium distachyon (Brachypodium) is now intensively utilized as a model grass species in various biological studies. Its favorable cytological features create a unique foundation for a convenient system in mutagenesis, thereby potentially enabling the 'hot spots' and 'cold spots' of DNA damage in its genome to be analyzed. The aim of this study was to analyze the involvement of 5S rDNA, 25S rDNA, the Arabidopsis-type (TTTAGGG)n telomeric sequence and the Brachypodium-originated centromeric BAC clone CB33J12 in the micronuclei formation in Brachypodium root tip cells that were subjected to the chemical clastogenic agent maleic hydrazide (MH). To the best of our knowledge, this is the first use of a multicolor fluorescence in situ hybridization (mFISH) with four different DNA probes being used simultaneously to study plant mutagenesis. A quantitative analysis allowed ten types of micronuclei, which were characterized by the presence or absence of specific FISH signal(s), to be distinguished, thus enabling some specific rules governing the composition of the MH-induced micronuclei with the majority of them originating from the terminal regions of chromosomes, to be identified. The application of rDNA sequences as probes showed that 5S rDNA-bearing chromosomes are involved in micronuclei formation more frequently than the 25S rDNA-bearing chromosomes. These findings demonstrate the promising potential of Brachypodium to be a useful model organism to analyze the effects of various genotoxic agents on the plant nuclear genome stability, especially when the complex FISH-based and chromosome-specific approaches such as chromosome barcoding and chromosome painting will be applied in future studies.


Assuntos
Brachypodium/genética , Coloração Cromossômica/métodos , Cromossomos de Plantas/efeitos dos fármacos , Hidrazida Maleica/farmacologia , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos/métodos , Mutagênese , Mutagênicos/farmacologia , Brachypodium/efeitos dos fármacos , Centrômero/efeitos dos fármacos , Centrômero/ultraestrutura , Cromossomos Artificiais Bacterianos/efeitos dos fármacos , Cromossomos de Plantas/ultraestrutura , Sondas de DNA , DNA Ribossômico/genética , Genoma de Planta , Germinação , Interfase , Mitose , Raízes de Plantas , RNA de Plantas/biossíntese , RNA de Plantas/genética , Sementes/efeitos dos fármacos , Telômero/efeitos dos fármacos , Telômero/ultraestrutura
12.
Artigo em Inglês | MEDLINE | ID: mdl-27908384

RESUMO

The temporal and spatial properties of DNA replication in plants related to DNA damage and mutagenesis is poorly understood. Experiments were carried out to explore the relationships between DNA replication, chromatin structure and DNA damage in nuclei from barley root tips. We quantitavely analysed the topological organisation of replication foci using pulse EdU labelling during the S phase and its relationship with the DNA damage induced by mutagenic treatment with maleic hydrazide (MH), nitroso-N-methyl-urea (MNU) and gamma ray. Treatment with mutagens did not change the characteristic S-phase patterns in the nuclei; however, the frequencies of the S-phase-labelled cells after treatment differed from those observed in the control cells. The analyses of DNA replication in barley nuclei were extended to the micronuclei induced by mutagens. Replication in the chromatin of the micronuclei was rare. The results of simultanous TUNEL reaction to identify cells with DNA strand breaks and the labelling of the S-phase cells with EdU revealed the possibility of DNA replication occurring in damaged nuclei. For the first time, the intensity of EdU fluorescence to study the rate of DNA replication was analysed.


Assuntos
Dano ao DNA/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , DNA de Plantas/efeitos dos fármacos , Hordeum/efeitos dos fármacos , Hordeum/genética , Mutagênese/efeitos dos fármacos , Mutagênicos/toxicidade , Núcleo Celular/efeitos dos fármacos , Raios gama , Marcação In Situ das Extremidades Cortadas/métodos , Hidrazida Maleica/toxicidade
13.
PLoS One ; 11(6): e0156865, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27257817

RESUMO

In the present study, the combination of the micronucleus test with analysis of the activity of the rRNA genes in mutagen-treated Hordeum vulgare (barley) by maleic hydrazide (MH) cells was performed. Simultaneously fluorescence in situ hybridization (FISH) with 25S rDNA as probes and an analysis of the transcriptional activity of 35S rRNA genes with silver staining were performed. The results showed that transcriptional activity is always maintained in the micronuclei although they are eliminated during the next cell cycle. The analysis of the transcriptional activity was extended to barley nuclei. MH influenced the fusion of the nucleoli in barley nuclei. The silver staining enabled detection of the nuclear bodies which arose after MH treatment. The results confirmed the usefulness of cytogenetic techniques in the characterization of micronuclei. Similar analyses can be now extended to other abiotic stresses to study the response of plant cells to the environment.


Assuntos
Hordeum/genética , RNA Ribossômico/genética , Cromossomos de Plantas/genética , DNA de Plantas/genética , Hordeum/efeitos dos fármacos , Hibridização in Situ Fluorescente , Hidrazida Maleica/toxicidade , Testes para Micronúcleos , Mutagênese/efeitos dos fármacos , Mutagênese/genética , Mutagênicos/toxicidade , Ativação Transcricional/efeitos dos fármacos , Ativação Transcricional/genética
14.
PLoS One ; 10(4): e0125092, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25910193

RESUMO

An efficient method for crossing green foxtail (Setaria viridis) is currently lacking. S. viridis is considered to be the new model plant for the study of C4 system in monocots and so an effective crossing protocol is urgently needed. S. viridis is a small grass with C4-NADP (ME) type of photosynthesis and has the advantage of having small genome of about 515 Mb, small plant stature, short life cycle, multiple tillers, and profuse seed set, and hence is an ideal model species for research. The objectives of this project were to develop efficient methods of emasculation and pollination, and to speed up generation advancement. We assessed the response of S. viridis flowers to hot water treatment (48°C) and to different concentrations of gibberellic acid, abscisic acid, maleic hydrazide (MH), and kinetin. We found that 500 µM of MH was effective in the emasculation of S. viridis, whilst still retaining the receptivity of the stigma to pollination. We also report effective ways to accelerate the breeding cycle of S. viridis for research through the germination of mature as well as immature seeds in optimized culture media. We believe these findings will be of great interest to researchers using Setaria.


Assuntos
Hibridização Genética/efeitos dos fármacos , Hibridização Genética/genética , Hidrazida Maleica/farmacologia , Setaria (Planta)/efeitos dos fármacos , Setaria (Planta)/genética , Ácido Abscísico/farmacologia , Flores/efeitos dos fármacos , Flores/genética , Genoma de Planta/efeitos dos fármacos , Genoma de Planta/genética , Germinação/efeitos dos fármacos , Germinação/genética , Giberelinas/farmacologia , Cinetina/farmacologia , Fotossíntese/efeitos dos fármacos , Fotossíntese/genética , Polinização/efeitos dos fármacos , Polinização/genética , Sementes/efeitos dos fármacos , Sementes/genética
15.
J Toxicol Environ Health A ; 78(6): 369-80, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25734764

RESUMO

Assessment of genotoxic properties of chemicals is mainly conducted only for single chemicals, without taking mixture genotoxic effects into consideration. The current study assessed mixture effects of the three known genotoxic chemicals, 2,4-dichlorophenoxyacetic acid (2,4-D), acrylamide (AA), and maleic hydrazide (MH), in an experiment with a fixed ratio design setup. The genotoxic effects were assessed with the single-cell gel electrophoresis assay (comet assay) for both single chemicals and the ternary mixture. The concentration ranges used were 0-1.4, 0-20, and 0-37.7 mM for 2,4-D, AA, and MH, respectively. Mixture toxicity was tested with a fixed ratio design at a 10:23:77% ratio for 2.4-D:AA:MH. Results indicated that the three chemicals yielded a synergistic mixture effect. It is not clear which mechanisms are responsible for this interaction. A few possible interactions are discussed, but further investigations including in vivo studies are needed to clarify how important these more-than-additive effects are for risk assessment.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Acrilamida/toxicidade , Dano ao DNA , DNA/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Hidrazida Maleica/toxicidade , Células CACO-2 , Ensaio Cometa , Herbicidas/toxicidade , Humanos , Reguladores de Crescimento de Plantas/toxicidade
16.
N Biotechnol ; 32(6): 739-46, 2015 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-25639197

RESUMO

Ergot alkaloids are widely used in the pharmaceutical industry in drug preparations for treating migraines and Parkinson's disease, inducing uterine contraction, and other purposes. Phytopathogenic fungi of the genus Claviceps (e.g. C. purpurea) comprise a major biological source of ergot alkaloids. Worldwide industrial production of these alkaloids derives almost equally from two biotechnological procedures: submerged culture of the fungus in fermenters and field parasitic production in dormant fungal organs known as sclerotia (also termed ergot). Ergot yields from field cultivation are greatly affected by weather and also can be much reduced by pollen contamination from imperfectly male-sterile rye, as only unfertilized ovaries can be infected by C. purpurea spores. Two substances with gametocidal effect - maleic hydrazide and 2-chloroethylphosphonic acid - were tested during three consecutive seasons in small field experiments for the ability to induce or amplify the male sterility of rye as well as the impacts on germination of C. purpurea spores and general vitality of rye host plants. Maleic hydrazide was proven to be a highly effective gametocide on both a fertile rye variety and a variety with imperfectly induced cytoplasmic male sterility. It showed negligible effect on germination of C. purpurea spores. Both accurate dosaging of the active gametocidal compound and timing of the application just 2-3 weeks before onset of anthesis proved crucial to achieving high ergot yield with minimum grain impurities.


Assuntos
Alcaloides de Claviceps/biossíntese , Células Germinativas Vegetais/efeitos dos fármacos , Hidrazida Maleica/administração & dosagem , Compostos Organofosforados/administração & dosagem , Infertilidade das Plantas/fisiologia , Secale/metabolismo , Relação Dose-Resposta a Droga , Alcaloides de Claviceps/isolamento & purificação , Reguladores de Crescimento de Plantas/farmacologia , Infertilidade das Plantas/efeitos dos fármacos , Secale/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologia
17.
Artigo em Inglês | MEDLINE | ID: mdl-25440906

RESUMO

In the field of contaminated sites and soil management, chemical analyses only bring typological data about pollution. As far as bioavailability and effects on organisms are concerned, we need ecotoxicology tools. In this domain, among many existing tests, we chose to study genotoxicity because it is a short-term endpoint with long-term consequences. The aim of this study is to assess the effects of soil pH on the results of the Vicia faba root tip micronucleus test for the two following reasons: (i) to define the pH range within which the test can be performed without modifying the soil to be tested, within the framework of the ISO standard of the test and (ii) to provides information about the effects of the pH on the genotoxic potential of soils. In this context, we modified the pH of a standard soil with HCl or NaOH and we spiked the matrix with copper (2, 4 and 8 mmol kg(-1) dry soil) or with maleic hydrazide, an antigerminative chemical (5, 10 and 20 µmol kg(-1) dry soil). We concluded that the pH had no effect on the mitotic index or micronucleus frequency in the root cells of the negative controls: extreme pH values did not induce micronucleus formation in root cells. Moreover, according to our results, the Vicia-micronucleus test can be performed with pH values ranging between 3.2 and 9.0, but in the ISO 29200 "Soil quality--assessment of genotoxic effects on higher plants--V. faba micronucleus test" we recommended to use a control soil with a pH value ranging between 5 and 8 for a more accurate assessment of chemical genotoxicity. We also found that acid pH could increase the genotoxic potential of pollutants, especially heavy metals. With hydrazide maleic spiked soil, plants were placed in a situation of double stress, i.e. toxicity caused by extreme pH values and toxicity induced by the pollutant.


Assuntos
Cobre/toxicidade , Hidrazida Maleica/toxicidade , Testes para Micronúcleos , Poluentes do Solo/toxicidade , Vicia faba/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Meristema/efeitos dos fármacos , Testes para Micronúcleos/métodos , Índice Mitótico , Solo/química , Vicia faba/genética
18.
Plant Sci ; 225: 86-94, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25017163

RESUMO

Seedlessness is a highly desirable characteristic in fresh fruits. However, post-fertilization seed abortion of cross-pollinated citrus fruit is uncommon. The factors regulating stenospermocarpy in citrus are unknown. In this research, we induced stenospermocarpy interfering in newly fertilized ovule cell division. The research also elucidates the most sensitive stage for ovule/seed abortion in citrus. Experiments were conducted with 'Afourer' mandarin that cross-pollinates with several cultivars and species. Cross-pollinated fruitlets were treated with maleic hydrazide (MH), a systemic growth regulator that specifically interferes in cell division. MH reduced ovule growth rate, the number of cell layers in nucella and inhibited embryo sac expansion; moreover, the treatment increased callose accumulation in nucella and surrounding the embryo sac. Fruits developed an early-aborted seed type with an immature, soft and edible seed coat. Seed number (-80%) and seed weight (-46%) were reduced in mature fruits. MH also hampered cell division in ovary walls, mesocarp and endocarp, thus reducing daily fruitlet growth and increasing fruit abscission. Stenospermocarpy could only be induced for a short period of time in the progamic phase of fertilization, specifically, when ovules are ready to be fertilized (7 days after anthesis) to early stages of embryo sac development (14 days after anthesis).


Assuntos
Divisão Celular/efeitos dos fármacos , Citrus/efeitos dos fármacos , Hidrazida Maleica/farmacologia , Óvulo Vegetal/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Polinização , Sementes/efeitos dos fármacos , Frutas/efeitos dos fármacos , Glucanos/metabolismo
19.
J Appl Genet ; 55(4): 449-56, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24939040

RESUMO

In addition to their normal developmental processes, plants have evolved complex genetic and epigenetic regulatory mechanisms to cope with various environmental stresses. It has been shown that both DNA methylation and histone modifications are involved in DNA damage response to various types of stresses. In this study, we focused on the involvement of two mutagenic agents, chemical (maleic acid hydrazide; MH) and physical (gamma rays), on the global epigenetic modifications of chromatin in barley. Our results indicate that both mutagens strongly influence the level of histone methylation and acetylation. Moreover, we found that gamma irradiation, in contrast to MH, has a more robust influence on the DNA methylation level. This is the first study that brings together mutagenic treatment along with its impact at the level of epigenetic modifications examined using the immunohistochemical method.


Assuntos
Cromatina/efeitos dos fármacos , Cromatina/efeitos da radiação , Epigênese Genética/efeitos dos fármacos , Epigênese Genética/efeitos da radiação , Raios gama/efeitos adversos , Hordeum/genética , Hidrazida Maleica/toxicidade , Acetilação , Metilação de DNA/efeitos dos fármacos , Metilação de DNA/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Herbicidas/toxicidade , Histonas/genética , Histonas/metabolismo , Hordeum/efeitos dos fármacos , Hordeum/crescimento & desenvolvimento , Hordeum/efeitos da radiação , Técnicas Imunoenzimáticas
20.
J Photochem Photobiol B ; 135: 48-54, 2014 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-24796645

RESUMO

Kinetic and mechanistic aspects of the photochemical and microbiological degradation of the herbicide Maleic Hydrazide (MH) have been studied. Riboflavin (Rf, vitamin B2) was employed as a main photosensitizer whereas Humic Acid (HA) was included as a second sensitizer in order to more closely simulate natural environmental conditions. MH quenches excited singlet and triplet states of Rf, with rate constants close to the diffusion limit. The herbicide and dissolved molecular oxygen competitively quench triplet excited Rf. As a consequence the reactive oxygen species (ROS), superoxide radical anion (O2(-·)), hydrogen peroxide (H2O2) and singlet molecular oxygen (O2((1)Δg)) are produced by electron- and energy-transfer processes, respectively, as demonstrated by auxiliary experiments employing selective auxiliary quenchers and the exclusive O2((1)Δg) generator Rose Bengal (RB). As a global result, the photodegradation of Rf is retarded, whereas MH is degraded by the generated ROS. The bacteria Pseudomonas aeruginosa (Ps) and Bacillus subtilis (Bs), recognized as contaminants surface-water and soil and microbial antagonists of phytopathogenic, were used in the microbiological experiments. Results of the individual incubation of both bacteria in in the presence of MH indicate a stimulation on the Ps growth, implying the biodegradation of the herbicide, whereas MH only exerted a bacteriostatic effect on Bs.


Assuntos
Bacillus subtilis/metabolismo , Herbicidas/química , Herbicidas/metabolismo , Hidrazida Maleica/química , Fotólise , Pseudomonas aeruginosa/metabolismo , Biodegradação Ambiental , Elétrons , Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Poluentes Ambientais/metabolismo , Herbicidas/isolamento & purificação , Substâncias Húmicas , Cinética , Fármacos Fotossensibilizantes/química , Espécies Reativas de Oxigênio/química , Riboflavina/química
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