Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 326
Filtrar
1.
J Am Soc Mass Spectrom ; 32(9): 2490-2494, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34374553

RESUMO

Laser-ablation electrospray ionization mass spectrometry (LAESI-MS) is an emerging method that has the potential to transform the field of metabolomics. This is in part due to LAESI-MS being an ambient ionization method that requires minimal sample preparation and uses (endogenous) water for in situ analysis. This application note details the employment of the "LAESI microscope" source to perform spatially resolved MS analysis of cells and MS imaging (MSI) of tissues at high spatial resolution. This source configuration utilizes a long-working-distance reflective objective that permits both visualization of the sample and a smaller LAESI laser beam profile than conventional LAESI setups. Here, we analyzed 200 single cells of Allium cepa (red onion) and imaged Fittonia argyroneura (nerve plant) in high spatial resolution using this source coupled to a Fourier transform mass spectrometer for high-mass-resolution and high-mass-accuracy metabolomics.


Assuntos
Metabolômica/métodos , Imagem Molecular/métodos , Análise de Célula Única/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Processamento de Imagem Assistida por Computador , Cebolas/citologia , Cebolas/metabolismo
2.
Anal Bioanal Chem ; 413(25): 6267-6277, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34355255

RESUMO

In this work, a novel fluorescent probe CBO was synthesized for detecting Fe2+ using the natural monoterpenketone camphor as the starting material. The probe CBO displayed turn-on fluorescence to Fe2+ accompanied by the solution change from colorless to green. As expected, there was an excellent linear relationship between the fluorescence intensity of probe CBO and the concentration of Fe2+ (0-20 µM), and the detection limit was as low as 1.56×10-8 M. In particular, CBO could selectively sense Fe2+ more than other analytes (Fe3+ included) through the N-oxide strategy, and quickly responded to Fe2+ (60 s) over a wide pH (4-14) range. Additionally, based on the rapid fluorescence response of CBO to Fe2+, a simple test strip-based detector was designed for boosting practical applicability. The probe CBO had been successfully applied to the fluorescence imaging of Fe2+ in onion cells and living zebrafish. The probe CBO was a powerful tool of detecting Fe2+ level in organisms, which was of significance to understand the role of Fe2+ in Fe2+-related physical processes and diseases.


Assuntos
Cânfora/química , Corantes Fluorescentes/química , Ferro/química , Animais , Concentração de Íons de Hidrogênio , Modelos Moleculares , Estrutura Molecular , Cebolas/citologia , Sensibilidade e Especificidade , Peixe-Zebra
3.
Plant J ; 107(6): 1616-1630, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34216173

RESUMO

Glutamine is a product of ammonium (NH4+ ) assimilation catalyzed by glutamine synthetase (GS) and glutamate synthase (GOGAT). The growth of NH4+ -preferring paddy rice (Oryza sativa L.) depends on root NH4+ assimilation and the subsequent root-to-shoot allocation of glutamine; however, little is known about the mechanism of glutamine storage in roots. Here, using transcriptome and reverse genetics analyses, we show that the rice amino acid transporter-like 6 (OsATL6) protein exports glutamine to the root vacuoles under NH4+ -replete conditions. OsATL6 was expressed, along with OsGS1;2 and OsNADH-GOGAT1, in wild-type (WT) roots fed with sufficient NH4 Cl, and was induced by glutamine treatment. We generated two independent Tos17 retrotransposon insertion mutants showing reduced OsATL6 expression to determine the function of OsATL6. Compared with segregants lacking the Tos17 insertion, the OsATL6 knock-down mutant seedlings exhibited lower root glutamine content but higher glutamine concentration in the xylem sap and greater shoot growth under NH4+ -replete conditions. The transient expression of monomeric red fluorescent protein-fused OsATL6 in onion epidermal cells confirmed the tonoplast localization of OsATL6. When OsATL6 was expressed in Xenopus laevis oocytes, glutamine efflux from the cell into the acidic bath solution increased. Under sufficient NH4+ supply, OsATL6 transiently accumulated in sclerenchyma and pericycle cells, which are located adjacent to the Casparian strip, thus obstructing the apoplastic solute path, and in vascular parenchyma cells of WT roots before the peak accumulation of GS1;2 and NADH-GOGAT1 occurred. These findings suggest that OsATL6 temporarily stores excess glutamine, produced by NH4+ assimilation, in root vacuoles before it can be translocated to the shoot.


Assuntos
Sistemas de Transporte de Aminoácidos/metabolismo , Glutamina/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Sistemas de Transporte de Aminoácidos/genética , Amônia/metabolismo , Cloreto de Amônio/farmacologia , Animais , Feminino , Regulação da Expressão Gênica de Plantas , Homeostase , Mutação , Cebolas/citologia , Cebolas/genética , Oócitos/metabolismo , Oryza/efeitos dos fármacos , Oryza/genética , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/genética , Raízes de Plantas/citologia , Raízes de Plantas/efeitos dos fármacos , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plantas Geneticamente Modificadas , Vacúolos/metabolismo , Xenopus laevis
4.
Appl Opt ; 60(17): 5081-5086, 2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34143073

RESUMO

A new, to the best of our knowledge, method for Stokes vector imaging is proposed to achieve imaging and dynamic monitoring of a non-labeled cytomembrane. In this work, a polarization state vector is described by a Stokes vector and expressed in chrominance space. A physical quantity called polarization chromaticity value (PCV) corresponding to a Stokes vector is used as the imaging parameter to perform Stokes vector imaging. By using the PCV imaging technique, the Stokes vector can be expressed in three-dimensional real space rather than in a Poincare sphere. Furthermore, a four-way Stokes parameter confocal microscopy system is designed to measure four Stokes parameters simultaneously and obtain micro-imaging. Label-free living onion cell membranes and their plasmolysis process are selected as the representative micro-anisotropy experimental analysis. It is proved that PCV imaging can perform visualization of cytomembranes, and further, microscopic orientation is demonstrated. The prospect of universal measurement of anisotropy details for analysis and diagnosis is provided.


Assuntos
Estruturas da Membrana Celular/fisiologia , Microscopia Confocal/métodos , Microscopia de Polarização/métodos , Cebolas/citologia , Imagem Óptica/métodos , Células Vegetais/fisiologia , Anisotropia , Interpretação de Imagem Assistida por Computador
5.
Appl Opt ; 60(15): 4418-4425, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-34143133

RESUMO

A single-shot dual-wavelength digital holographic microscopy with an adjustable off-axis configuration is presented, which helps realize real-time quantitative phase imaging for living cells. With this configuration, two sets of interference fringes corresponding to their wavelengths can be flexibly recorded onto one hologram in one shot. The universal expression on the dual-wavelength hologram recorded under any wave vector orientation angles of reference beams is given. To avoid as much as possible the effect of zero-order spectrum, we can flexibly select their carry frequencies for the two wavelengths using this adjustable off-axis configuration, according to the distribution feature of object's spatial-frequency spectrum. This merit is verified by a quantitative phase imaging experiment for the microchannel of a microfluidic chip. The reconstructed phase maps of living onion epidermal cells exhibit cellular internal life activities, for the first time to the best of our knowledge, vividly displaying the progress of the nucleus, cell wall, cytoskeleton, and the substance transport in microtubules inside living cells. These imaging results demonstrate the availability and reliability of the presented method for real-time quantitative phase imaging.


Assuntos
Holografia/métodos , Processamento de Imagem Assistida por Computador/métodos , Técnicas Analíticas Microfluídicas/métodos , Cebolas/citologia , Epiderme Vegetal/citologia , Sistemas Computacionais , Microscopia/métodos
6.
PLoS One ; 16(5): e0250650, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33951055

RESUMO

The primary plant cell wall is a complex matrix composed of interconnected polysaccharides including cellulose, hemicellulose, and pectin. Changes of this dynamic polysaccharide system play a critical role during plant cell development and differentiation. A better understanding of cell wall architectures can provide insight into the plant cell development. In this study, a Raman spectroscopic imaging approach was developed to visualize the distribution of plant cell wall polysaccharides. In this approach, Surface-enhanced Raman scattering (SERS through self-assembled silver nanoparticles) was combined with Raman labels (4-Aminothiophenol. 4ATP) and targeted enzymatic hydrolysis to improve the sensitivity, specificity, and throughput of the Raman imaging technique, and to reveal the distribution of pectin and its co-localization with xyloglucan inside onion epidermal cell (OEC) wall. This technique significantly decreased the required spectral acquisition time. The resulted Raman spectra showed a high Raman signal. The resulted Raman images successfully revealed and characterized the pectin distribution and its co-localization pattern with xyloglucan in OEC wall.


Assuntos
Parede Celular/metabolismo , Glucanos/metabolismo , Cebolas/citologia , Pectinas/metabolismo , Epiderme Vegetal/citologia , Análise Espectral Raman , Xilanos/metabolismo , Transporte Proteico
7.
Int J Mol Sci ; 22(6)2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33809693

RESUMO

The N-terminal of Myc-like basic helix-loop-helix transcription factors (bHLH TFs) contains an interaction domain, namely the MYB-interacting region (MIR), which interacts with the R2R3-MYB proteins to regulate genes involved in the anthocyanin biosynthetic pathway. However, the functions of MIR-domain bHLHs in this pathway are not fully understood. In this study, PbbHLH2 containing the MIR-domain was identified and its function investigated. The overexpression of PbbHLH2 in "Zaosu" pear peel increased the anthocyanin content and the expression levels of late biosynthetic genes. Bimolecular fluorescence complementation showed that PbbHLH2 interacted with R2R3-MYB TFs PbMYB9, 10, and 10b in onion epidermal cells and confirmed that MIR-domain plays important roles in the interaction between the MIR-domain bHLH and R2R3-MYB TFs. Moreover, PbbHLH2 bound and activated the dihydroflavonol reductase promoter in yeast one-hybrid (Y1H) and dual-luciferase assays. Taken together these results suggested that the MIR domain of PbbHLH2 regulated anthocyanin biosynthesis in pear fruit peel.


Assuntos
Antocianinas/biossíntese , Fatores de Transcrição Hélice-Alça-Hélice Básicos/química , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Vias Biossintéticas , Frutas/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Pyrus/metabolismo , Sequência de Aminoácidos , Frutas/genética , Regulação da Expressão Gênica de Plantas , Cebolas/citologia , Filogenia , Epiderme Vegetal/citologia , Proteínas de Plantas/genética , Regiões Promotoras Genéticas , Ligação Proteica , Domínios Proteicos , Pyrus/genética , Relação Estrutura-Atividade
8.
Opt Express ; 29(5): 7060-7069, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33726214

RESUMO

Fast 3D volumetric imaging has been essential for biology, medicine and industrial inspections, and various optical coherence tomography (OCT) methods have been developed to meet such needs. Point-scanning based approaches, such as swept-source OCT and spectral domain OCT, can obtain a depth information at once, but they require lateral scan for full 3D imaging. On the contrary, full-field OCT needs the scanning of imaging depth while it records a full lateral information at once. Here, we present a full-field OCT system that can obtain multi-depth information at once by a single-shot recording. We combine a 2D diffraction grating and a custom-made echelon to prepare multiple reference beams having different pathlengths and propagating angles. By recording a single interference image between the reflected wave from a sample and these multiple reference beams, we reconstruct full-field images at multiple depths associated with the pathlengths of the individual reference beams. We demonstrated the single-shot recording of 7 different depth images at 10 µm for biological tissues. Our method can potentially be useful for applications where high-speed recording of multiple en-face images is crucial.


Assuntos
Imageamento Tridimensional/métodos , Tomografia de Coerência Óptica/instrumentação , Cebolas/citologia , Imagens de Fantasmas
9.
Biomolecules ; 11(1)2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33450991

RESUMO

Before replicating, Pospiviroidae viroids must move into the plant nucleus. However, the mechanisms of viroid nuclear import are not entirely understood. To study the nuclear import of viroids, we established a nuclear import assay system using onion cell strips and observed the import of Alexa Fluor-594-labeled citrus exocortis viroid (CEVd). To identify the plant factors involved in the nuclear import of viroids, we cloned the Viroid RNA-binding Protein 1 (VIRP1) gene from a tomato cultivar, Seokwang, and heterologously expressed and purified the VIRP1 protein. The newly prepared VIRP1 protein had alterations of amino acid residues at two points (H52R, A277G) compared with a reference VIRP1 protein (AJ249595). VIRP1 specifically bound to CEVd and promoted its nuclear import. However, it is still uncertain whether VIRP1 is the only factor required for the nuclear import of CEVd because CEVd entered the plant nuclei without VIRP1 in our assay system. The cause of the observed nuclear accumulation of CEVd in the absence of VIRP1 needs to be further clarified.


Assuntos
Núcleo Celular/metabolismo , Citrus/virologia , Proteínas de Plantas/metabolismo , Viroides/metabolismo , Transporte Ativo do Núcleo Celular , Solanum lycopersicum , Cebolas/citologia , Epiderme Vegetal/citologia , Proteínas de Plantas/isolamento & purificação , Ligação Proteica
10.
J Ethnopharmacol ; 266: 113416, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32980485

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochia indica L. (Aristolochiaceae) is a common medicinal plant described in many traditional medicine as well as in Ayurveda used against snakebites. Besides, the plant has also been reported traditionally against fever, rheumatic arthritis, madness, liver ailments, dyspepsia, oedema, leishmaniasis, leprosy, dysmenorrhoea, sexual diseases etc. The plant is known to contain its major bioactive constituent aristolochic acid (AA) known for its anti-snake venom, abortifacient, antimicrobial and antioxidant properties. MATERIALS AND METHODS: This present work describes a validated, fast and reproducible high performance thin layer chromatography (HPTLC) method to estimate AA from the roots of 20 chemotypes of A. indica procured from 20 diverse geographical locations from the state of West Bengal, India. Further, an evidence-based approach was adopted to investigate the reported anti-venom activity of the aqueous extracts of the A. indica roots by assessing its phospholipase A2 (PLA2) inhibitory properties since PLA2 is a major component of many snake-venoms. Finally, the cytotoxicity and genotoxicity of the aqueous root extract of the Purulia (AI 1) chemotype were assessed at various concentrations using Allium cepa root meristematic cells. RESULTS: The highest amount of AA (7643.67 µg/g) was determined in the roots of A. indica chemotype collected from Purulia district followed by the chemotypes collected from Murshidabad, Jalpaiguri and Birbhum districts (7398.34, 7345.09 and 6809.97 µg/g respectively). This study not only determines AA in the plants to select pharmacologically elite chemotypes of A. indica, but it also identifies high AA producing A. indica for further domestication and propagation of the plants for pharmacological and industrial applications. The method was validated via analyzing inter-day and intra-day precision, repeatability, reproducibility, instrumental precision, limit of detection (LOD) and limit of quantification (LOQ) and specificity. Chemotypes with high AA content exhibited superior anti-PLA2 activity by selectively inhibiting human-group PLA2. Moreover, A. indica root extract significantly inhibited mitosis in Allium cepa root tips as a potent clastogen. CONCLUSIONS: The present quick, reproducible and validated HPTLC method provides an easy tool to determine AA in natural A. indica plant populations as well as in food and dietary supplements, a potential antivenin at one hand and a possible cause of aristolochic acid nephropathy (AAN) at another. Besides, the cytotoxic and mitotoxic properties of the root extracts should be used with caution especially for oral administration.


Assuntos
Antídotos/farmacologia , Aristolochia/química , Ácidos Aristolóquicos/farmacologia , Extratos Vegetais/farmacologia , Antídotos/isolamento & purificação , Antídotos/toxicidade , Ácidos Aristolóquicos/isolamento & purificação , Cromatografia em Camada Delgada , Humanos , Medicina Tradicional , Meristema/citologia , Meristema/efeitos dos fármacos , Mitose/efeitos dos fármacos , Testes de Mutagenicidade , Cebolas/citologia , Cebolas/efeitos dos fármacos , Inibidores de Fosfolipase A2/isolamento & purificação , Inibidores de Fosfolipase A2/farmacologia , Inibidores de Fosfolipase A2/toxicidade , Extratos Vegetais/química , Extratos Vegetais/toxicidade , Raízes de Plantas , Reprodutibilidade dos Testes
11.
Drug Chem Toxicol ; 44(2): 190-197, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30607990

RESUMO

Lavender and immortelle essential oils (EOs) are widely used to treat a spectrum of human conditions. The aim of this study was to investigate cyto/genotoxic effects of lavender and immortelle EOs using plant cells (Allium cepa) and human lymphocytes, as well as their antimicrobial potential using nine strains of bacteria and fungi. Our results for lavender and immortelle EOs showed that the frequency of chromosome aberrations (CAs) was increased in comparison with controls. For both oils, increased frequency of apoptosis for all concentrations, as well as the frequency of necrosis (0.10/0.30 µl/ml for lavender/immortelle, respectively) was demonstrated. In human lymphocytes, differences for minute fragments between immortelle oil (0.10 µl/ml) and controls were observed. Increased frequency of apoptosis was detected for immortelle oil (0.20 µl/ml), while both oils (0.20; 0.30 µl/ml lavender, and immortelle at all concentrations) induced higher frequency of necrosis in comparison with controls. Lavender EO was effective against all tested Gram-positive and Gram-negative bacteria, while immortelle EO inhibited only Gram-positive bacteria. Both oils exhibited antifungal effect. Our results demonstrated that lavender and immortelle EOs showed cyto/genotoxic effects in both, plant and human cells, as well as antimicrobial properties. Further studies are needed to strengthen these findings.


Assuntos
Helichrysum/química , Lavandula/química , Óleos Voláteis/isolamento & purificação , Óleos de Plantas/isolamento & purificação , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antibacterianos/toxicidade , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Antifúngicos/toxicidade , Apoptose/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Aberrações Cromossômicas , Relação Dose-Resposta a Droga , Fungos/efeitos dos fármacos , Humanos , Linfócitos/efeitos dos fármacos , Testes de Mutagenicidade , Óleos Voláteis/farmacologia , Óleos Voláteis/toxicidade , Cebolas/citologia , Cebolas/efeitos dos fármacos , Óleos de Plantas/farmacologia , Óleos de Plantas/toxicidade
12.
Opt Lett ; 45(13): 3443-3446, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32630867

RESUMO

Intensity levels allowed by safety standards (ICNIRP or ANSI) limit the amount of light that can be used in a clinical setting to image highly scattering or absorptive tissues with optical coherence tomography (OCT). To achieve high-sensitivity imaging at low intensity levels, we adapt a detection scheme-which is used in quantum optics for providing information about spectral correlations of photons-into a standard spectral domain OCT system. This detection scheme is based on the concept of dispersive Fourier transformation, where a fiber introduces a wavelength-dependent time delay measured by a single-pixel detector, usually a high-speed photoreceiver. Here, we use a fast superconducting single-photon detector SSPD as a single-pixel detector and obtain images of a glass stack and a slice of onion at the intensity levels of the order of 10 pW. We also provide a formula for a depth-dependent sensitivity falloff in such a detection scheme, which can be treated as a temporal equivalent of diffraction-grating-based spectrometers.


Assuntos
Teoria Quântica , Tomografia de Coerência Óptica/métodos , Análise de Fourier , Vidro , Cebolas/citologia , Fótons
13.
Artigo em Inglês | MEDLINE | ID: mdl-32684077

RESUMO

Plant models may be useful as test organisms for initial screening of potential toxicity of personal care products. The objective of the present study was to assess the efficacy of the Allium cepa (common onion) test system as a bioanalytical tool for screening potential cytotoxicity and genotoxicity of herbal-based hair dye formulations. Exposure of black hair dye formulations for 48 hours resulted in root growth retardation and mitosis suppression in the root meristems of A. cepa bulbs indicating concentration dependent cytotoxicity. At the 72 hour post exposure, cytotoxic effects on the roots were reduced but not recovered completely signifying prolong toxic action of the hair dyes. The condensed nuclei was the most frequent nuclear abnormality found in the dye exposed root meristematic cells indicating the cell death process. Induction of micronuclei and chromosomal aberrations in the root meristematic cells even at the post exposure stage indicates persistent genotoxicity of the hair dyes which may be attributed to the interactive effects of chemical mixtures present in the commercial hair dye formulations. The results revealed that A. cepa test system is an effective bioanalytical tool for screening cytogenotoxicity of commercial hair dye formulations.


Assuntos
Tinturas para Cabelo/farmacologia , Cebolas/efeitos dos fármacos , Aberrações Cromossômicas , Análise Citogenética , Dano ao DNA , Meristema/efeitos dos fármacos , Mitose , Cebolas/citologia , Cebolas/genética , Raízes de Plantas/efeitos dos fármacos
14.
Methods Mol Biol ; 2149: 225-237, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32617938

RESUMO

Field emission scanning electron microscopy (FESEM) is a powerful tool for analyzing surface structures of biological and nonbiological samples. However, when it is used to study fine structures of nanometer-sized microfibrils of epidermal cell walls, one often encounters tremendous challenges to acquire clear and undistorted images because of two major issues: (1) Preparation of samples suitable for high resolution imaging; due to the delicateness of some plant materials, such as onion epidermal cell walls, many things can happen during sample processing, which subsequently result in damaged samples or introduce artifacts. (2) Difficulties to acquire clear images of samples which are electron-beam sensitive and prone to charging artifacts at magnifications over 100,000×. In this chapter we described detailed procedures for sample preparation and conditions for high-resolution FESEM imaging of onion epidermal cell walls. The methods can be readily adapted for other wall materials.


Assuntos
Parede Celular/ultraestrutura , Celulose/ultraestrutura , Microscopia Eletrônica de Varredura/métodos , Processamento de Imagem Assistida por Computador , Cebolas/citologia , Cebolas/ultraestrutura , Epiderme Vegetal/citologia , Epiderme Vegetal/ultraestrutura
15.
IET Nanobiotechnol ; 14(2): 133-141, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32433030

RESUMO

Augmented escape of nanostructures to the ecosystem has necessitated the comprehensive study of their impact, especially on plants. In the current study, hematite nanoparticles were prepared by employing garlic extract and checked for their cytogenetic effect on onion roots and germination characteristics of five agricultural crops (Vigna radiata, Triticum aestivum, Trigonella foenum-graecum, Cicer arietinum and Vicia faba) in the concentration range of 20-100 mg/L. Onion roots exhibited an increased mitotic index till 60 mg/L dosage, beyond which trend decreased marginally. Percentage of aberrant chromosomes reported for 100 mg/L exposure was very low (3.358 ± 0.13%) and included common defects such as clumped/sticky metaphase, ring chromosomes, laggards, spindle abnormality, chromosome bridges etc. Moreover, comet assay, DNA laddering experiment and electron micrograph study confirmed negligible damage to onion roots. Seed germination study indicated a positive response in different agronomic traits (germination index, root length, fold change in weight and vigour index) up to 60 mg/L, beyond which either negative or neutral effect was observed. However, none of the samples showed 50% inhibition in germination index; highest being 33.33% inhibition for V. faba, compared to the control. In brief, biogenic hematite nanoparticles caused insignificant phytotoxicity and were likely assimilated as iron source at lower dosage.


Assuntos
Aberrações Cromossômicas/efeitos dos fármacos , Germinação/efeitos dos fármacos , Nanopartículas Magnéticas de Óxido de Ferro/toxicidade , Cebolas , Raízes de Plantas/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Mitose/efeitos dos fármacos , Testes de Mutagenicidade , Cebolas/citologia , Cebolas/efeitos dos fármacos , Cebolas/genética , Sementes/efeitos dos fármacos
16.
IET Nanobiotechnol ; 14(2): 161-166, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32433034

RESUMO

The production of different size and shape silver nanoparticles (AgNPs) has increased considerably in recent years due to several commercial and biological applications. Here, rod-shaped AgNPs (SNRs) were prepared using the microwave-assisted method and characterised by ultraviolet-visible spectroscopy, and transmission electron microscopy analysis. The present study aims to investigate the cyto-genotoxic effect of various concentrations (5, 10, and 15 µM) of SNRs using Allium cepa model. As a result, concentration-dependent cyto-genotoxic effect of SNRs was observed through a decrease in the mitotic index, and an increase in the chromosomal aberrations such as chromosome break, disturbed metaphase, and anaphase bridge. To check the impact of Ag+ ions, 15 µM silver nitrate (AgNO3) was prepared and tested in all the assays. Furthermore, cell viability and different reactive oxygen species assays were performed to test the cytotoxicity evaluation of SNRs. The authors found that in all the tested assays, SNRs at high concentrations (15 µM) and AgNO3 (15 µM) were observed to cause maximal damage to the roots. Therefore, the current study implies that the cytotoxicity and genotoxicity of SNRs were dependent on the concentration of SNRs.


Assuntos
Aberrações Cromossômicas/efeitos dos fármacos , Nanopartículas Metálicas/química , Cebolas/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Prata/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Cebolas/citologia , Cebolas/genética , Raízes de Plantas/efeitos dos fármacos , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Prata/química
17.
Sci Rep ; 10(1): 5243, 2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-32251298

RESUMO

Rice blast resistance gene, Pi54 provides broad-spectrum resistance against different strains of Magnaporthe oryzae. Understanding the cellular localization of Pi54 protein is an essential step towards deciphering its place of interaction with the cognate Avr-gene. In this study, we investigated the sub-cellular localization of Pi54 with Green Fluorescent Protein (GFP) as a molecular tag through transient and stable expression in onion epidermal cells (Allium cepa) and susceptible japonica cultivar rice Taipei 309 (TP309), respectively. Confocal microscopy based observations of the onion epidermal cells revealed nucleus and cytoplasm specific GFP signals. In the stable transformed rice plants, GFP signal was recorded in the stomata, upper epidermal cells, mesophyll cells, vascular bundle, and walls of bundle sheath and bulliform cells of leaf tissues. These observations were further confirmed by Immunocytochemical studies. Using GFP specific antibodies, it was found that there was sufficient aggregation of GFP::Pi54protein in the cytoplasm of the leaf mesophyll cells and periphery of the epidermal cells. Interestingly, the transgenic lines developed in this study could show a moderate level of resistance to Xanthomonas oryzae and Rhizoctonia solani, the causal agents of the rice bacterial blight and sheath blight diseases, respectively. This study is a first detailed report, which emphasizes the cellular and subcellular distribution of the broad spectrum blast resistance gene Pi54 in rice and the impact of its constitutive expression towards resistance against other fungal and bacterial pathogens of rice.


Assuntos
Oryza/genética , Oryza/microbiologia , Doenças das Plantas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Resistência à Doença/genética , Imunofluorescência , Proteínas de Fluorescência Verde/genética , Interações Hospedeiro-Patógeno/genética , Magnaporthe/patogenicidade , Cebolas/citologia , Cebolas/genética , Oryza/citologia , Células Vegetais , Doenças das Plantas/microbiologia , Folhas de Planta/citologia , Plantas Geneticamente Modificadas , Rhizoctonia/patogenicidade , Xanthomonas/patogenicidade
18.
Plant Cell Rep ; 39(8): 1013-1028, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32328702

RESUMO

KEY MESSAGE: Induction of biphasic interphase-mitotic cells and PCC is connected with an increased level of metabolism in root meristem cells of Allium cepa. Previous experiments using primary roots of Allium cepa exposed to low concentrations of hydroxyurea have shown that long-term DNA replication stress (DRS) disrupts essential links of the S-M checkpoint mechanism, leading meristem cells either to premature chromosome condensation (PCC) or to a specific form of chromatin condensation, establishing biphasic organization of cell nuclei with both interphase and mitotic domains (IM cells). The present study supplements and extends these observations by describing general conditions under which both abnormal types of M-phase cells may occur. The analysis of root apical meristem (RAM) cell proliferation after prolonged mild DRS indicates that a broad spectrum of inhibitors is capable of generating PCC and IM organization of cell nuclei. These included: 5-aminouracil (5-AU, a thymine antagonist), characterized by the highest efficiency in creating cells with the IM phenotype, aphidicolin (APH), an inhibitor of DNA polymerase α, 5-fluorodeoxyuridine (FUdR), an inhibitor of thymidylate synthetase, methotrexate (MTX), a folic acid analog that inhibits purine and pyrimidine synthesis, and cytosine arabinoside (Ara-C), which inhibits DNA replication by forming cleavage complexes with topoisomerase I. As evidenced using fluorescence-based click chemistry assays, continuous treatment of onion RAM cells with 5-AU is associated with an accelerated dynamics of the DNA replication machinery and significantly enhanced levels of transcription and translation. Furthermore, DRS conditions bring about an intensified production of hydrogen peroxide (H2O2), depletion of reduced glutathione (GSH), and some increase in DNA fragmentation, associated with only a slight increase in apoptosis-like programmed cell death events.


Assuntos
Replicação do DNA/efeitos dos fármacos , Interfase/efeitos dos fármacos , Meristema/citologia , Mitose/efeitos dos fármacos , Cebolas/citologia , Uracila/análogos & derivados , Apoptose/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Dano ao DNA , Fragmentação do DNA/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Cebolas/genética , Biossíntese de Proteínas/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Transcrição Gênica/efeitos dos fármacos , Uracila/farmacologia
19.
PLoS One ; 15(4): e0231082, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32240261

RESUMO

Increased periods of prolonged droughts followed by severe precipitation events are expected throughout South America due to climate change. Freshwater sediments are especially sensitive to these changing climate conditions. The increased oscillation of water levels in aquatic ecosystems causes enhanced cycles of sediment drying and rewetting. Here we experimentally evaluate the effects of induced drought followed by a rewetting event on the release of carbon dioxide (CO2), methane (CH4), nutrients (nitrogen and phosphorus), and trace elements (iron, manganese, and zinc) from the sediment of a tropical reservoir in southeastern Brazil. Furthermore, we used bulb onions (Allium cepa) to assess the potential cytogenotoxicity of the water overlying sediments after rewetting. We found peaks in CO2 and CH4 emissions when sediments first transitioned from wet to dry, with fluxes declining as sediments dried out. CO2 emissions peaked again upon rewetting, whereas CH4 emissions remained unaltered. Our experiment also revealed average increases by up to a factor of ~5000 in the release rates of nutrients and trace elements in water overlying sediments after rewetting. These increased release rates of potentially toxic compounds likely explain the lower replication of Allium cepa cells (up to 22% reduction) exposed to water overlying sediments after rewetting. Our findings suggest that increased events of drought followed by rewetting may lead to a range of changes in freshwater ecosystems, including nutrient enrichment, increased toxicity following resuspension of contaminants, and higher emission of greenhouse gases to the atmosphere.


Assuntos
Dessecação , Sedimentos Geológicos/química , Gases de Efeito Estufa/análise , Mutagênicos/toxicidade , Oligoelementos/análise , Água/química , Dióxido de Carbono/análise , Morte Celular/efeitos dos fármacos , Difusão , Metano/análise , Índice Mitótico , Nitrogênio/análise , Cebolas/citologia , Fósforo/análise
20.
Biotech Histochem ; 95(6): 464-473, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32037888

RESUMO

POINCIANELLA BRACTEOSA: (Tul.) L.P. Queiroz. (Fabaceae) traditionally is used in Brazilian medicine to treat catarrhal infections, diarrhea, hepatitis and anemia. We investigated the phytochemical profile, and mutagenicity and anti-mutagenicity of aqueous extracts of leaves of P. bracteosa in A. cepa cells and in mice. We investigated four concentrations of extract for the A. cepa bioassay and three doses of extract for administration to mice. For the A. cepa assay, we analyzed 5,000 meristematic cells to determine the mitotic index, mean number of chromosome alterations and percentage of damage reduction. For each animal assay, 2,000 normochromatic erythrocytes were evaluated per mouse to determine the number of micronuclei and the protective effect of the extract. Phytochemical analysis of the extract revealed reducing sugars, tannins and alkaloids, which likely did not interfere with the cell cycle of A. cepa or cause damage to the DNA of A. cepa or mice. The extract exhibited a protective effect in both organisms.


Assuntos
Allium/efeitos dos fármacos , Cebolas/citologia , Extratos Vegetais/farmacologia , Folhas de Planta/metabolismo , Animais , Aberrações Cromossômicas , Fabaceae/efeitos dos fármacos , Meristema/citologia , Meristema/efeitos dos fármacos , Camundongos , Cebolas/genética , Folhas de Planta/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...