Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Mol Sci ; 22(21)2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34768948

RESUMO

The objective of our study was to characterise the growth of tomato seedlings under various light spectra, but special attention has been paid to gaining a deeper insight into the details of photosynthetic light reactions. The following light combinations (generated by LEDs, constant light intensity at 300 µmol m-2 s-1) were used: blue/red light; blue/red light + far red; blue/red light + UV; white light that was supplemented with green, and white light that was supplemented with blue. Moreover, two combinations of white light for which the light intensity was changed by imitating the sunrise, sunset, and moon were also tested. The reference point was also light generated by high pressure sodium lamps (HPS). Plant growth/morphological parameters under various light conditions were only partly correlated with the photosynthetic efficiency of PSI and PSII. Illumination with blue/red as the main components had a negative effect on the functioning of PSII compared to the white light and HPS-generated light. On the other hand, the functioning of PSI was especially negatively affected under the blue/red light that was supplemented with FR. The FT-Raman studies showed that the general metabolic profile of the leaves (especially proteins and ß-carotene) was similar in the plants that were grown under the HPS and under the LED-generated white light for which the light intensity changed during a day. The effect of various light conditions on the leaf hormonal balance (auxins, brassinosteroids) is also discussed.

2.
Nat Plants ; 7(5): 619-632, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-34007032

RESUMO

Brassinosteroid (BR) hormones are indispensable for root growth and control both cell division and cell elongation through the establishment of an increasing signalling gradient along the longitudinal root axis. Because of their limited mobility, the importance of BR distribution in achieving a signalling maximum is largely overlooked. Expression pattern analysis of all known BR biosynthetic enzymes revealed that not all cells in the Arabidopsis thaliana root possess full biosynthetic machinery, and that completion of biosynthesis relies on cell-to-cell movement of hormone precursors. We demonstrate that BR biosynthesis is largely restricted to the root elongation zone, where it overlaps with BR signalling maxima. Moreover, optimal root growth requires hormone concentrations to be low in the meristem and high in the root elongation zone, attributable to increased biosynthesis. Our finding that spatiotemporal regulation of hormone synthesis results in local hormone accumulation provides a paradigm for hormone-driven organ growth in the absence of long-distance hormone transport in plants.


Assuntos
Brassinosteroides/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Brassinosteroides/biossíntese , Regulação da Expressão Gênica de Plantas , Meristema/metabolismo , Redes e Vias Metabólicas , Reguladores de Crescimento de Plantas/fisiologia , Raízes de Plantas/metabolismo
3.
Int J Mol Sci ; 22(6)2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33799719

RESUMO

Ecdysteroids (ECs) are steroid hormones originally found in the animal kingdom where they function as insect molting hormones. Interestingly, a relatively high number of these substances can also be formed in plant cells. Moreover, ECs have certain regulatory effects on plant physiology, but their role in plants still requires further study. One of the main aims of the present study was to verify a hypothesis that fenarimol, an inhibitor of the biosynthesis of ECs in the animal kingdom, also affects the content of endogenous ECs in plants using winter wheat Triticum aestivum L. as a model plant. The levels of endogenous ECs in winter wheat, including the estimation of their changes during a course of different temperature treatments, have been determined using a sensitive analytical method based on UHPLC-MS/MS. Under our experimental conditions, four substances of EC character were detected in the tissue of interest in amounts ranging from less than 1 to over 200 pg·g-1 FW: 20-hydroxyecdysone, polypodine B, turkesterone, and isovitexirone. Among them, turkesterone was observed to be the most abundant EC and accumulated mainly in the crowns and leaves of wheat. Importantly, the level of ECs was observed to be dependent on the age of the plants, as well as on growth conditions (especially temperature). Fenarimol, an inhibitor of a cytochrome P450 monooxygenase, was shown to significantly decrease the level of naturally occurring ECs in experimental plants, which may indicate its potential use in studies related to the biosynthesis and physiological function of these substances in plants.


Assuntos
Produtos Biológicos/metabolismo , Ecdisteroides/biossíntese , Pirimidinas/farmacologia , Triticum/metabolismo , Produtos Biológicos/química , Cromatografia Líquida/métodos , Ecdisteroides/química , Fungicidas Industriais/farmacologia , Estrutura Molecular , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Espectrometria de Massas em Tandem/métodos , Temperatura , Triticum/crescimento & desenvolvimento
4.
Biomolecules ; 11(4)2021 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-33918915

RESUMO

Neuroactive steroids are a family of all steroid-based compounds, of both natural and synthetic origin, which can affect the nervous system functions. Their biosynthesis occurs directly in the nervous system (so-called neurosteroids) or in peripheral endocrine tissues (hormonal steroids). Steroid hormone levels may fluctuate due to physiological changes during life and various pathological conditions affecting individuals. A deeper understanding of neuroactive steroids' production, in addition to reliable monitoring of their levels in various biological matrices, may be useful in the prevention, diagnosis, monitoring, and treatment of some neurodegenerative and psychiatric diseases. The aim of this review is to highlight the most relevant methods currently available for analysis of neuroactive steroids, with an emphasis on immunoanalytical methods and gas, or liquid chromatography combined with mass spectrometry.


Assuntos
Hormônios/sangue , Espectrometria de Massas/métodos , Neuroesteroides/sangue , Animais , Análise Química do Sangue/métodos , Hormônios/metabolismo , Humanos , Imunoensaio/métodos , Neuroesteroides/metabolismo
5.
Int J Mol Sci ; 22(1)2020 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-33375728

RESUMO

Brassinosteroids are a class of plant hormones that regulate a broad range of physiological processes such as plant growth, development and immunity, including the suppression of biotic and abiotic stresses. In this paper, we report the synthesis of new brassinosteroid analogues with a nitrogen-containing side chain and their biological activity on Arabidopis thaliana. Based on molecular docking experiments, two groups of brassinosteroid analogues were prepared with short and long side chains in order to study the impact of side chain length on plants. The derivatives with a short side chain were prepared with amide, amine and ammonium functional groups. The derivatives with a long side chain were synthesized using amide and ammonium functional groups. A total of 25 new brassinosteroid analogues were prepared. All 25 compounds were tested in an Arabidopsis root sensitivity bioassay and cytotoxicity screening. The synthesized substances showed no significant inhibitory activity compared to natural 24-epibrassinolide. In contrast, in low concentration, several compounds (8a, 8b, 8e, 16e, 22a and 22e) showed interesting growth-promoting activity. The cytotoxicity assay showed no toxicity of the prepared compounds on cancer and normal cell lines.


Assuntos
Brassinosteroides/síntese química , Brassinosteroides/farmacologia , Técnicas de Química Sintética , Nitrogênio/química , Arabidopsis/efeitos dos fármacos , Arabidopsis/crescimento & desenvolvimento , Brassinosteroides/química , Estrutura Molecular , Desenvolvimento Vegetal/efeitos dos fármacos
6.
Bioorg Chem ; 100: 103868, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32388425

RESUMO

Triterpene bidesmosides are considered as highly cytotoxic saponins, usually less toxic against normal cells than monodesmosides, and less haemolytic. Biological activity of the betulin-type bidesmosides, rarely found in Nature, and seldom prepared due to serious synthetic problems, is poorly recognized. We report herein a protocol for the preparation of disubstituted lupane saponins (betulin bidesmosides) by treatment of their benzoates with potassium carbonate in dichloromethane / methanol solution. Cytotoxicity of all compounds was tested in vitro for a series of cancer cell lines, as well as normal human skin BJ fibroblasts. Presence of l-rhamnose moiety is crucial for cytotoxicity of betulin bidesmosides. On the other hand, l-arabinose fragment connected to lupane C-3 carbon atom significantly decreases activity. Presented results clearly show that betulin bidesmosides have significant clinical potential as anticancer agents.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Triterpenos/química , Triterpenos/farmacologia , Antineoplásicos/síntese química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células HeLa , Humanos , Células MCF-7 , Neoplasias/tratamento farmacológico , Ramnose/análogos & derivados , Ramnose/síntese química , Ramnose/farmacologia , Relação Estrutura-Atividade , Triterpenos/síntese química
7.
Food Chem Toxicol ; 137: 111164, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32001316

RESUMO

Plant hormone brassinosteroids (BRs) have multiple important functions in plants. They have also been found to exhibit anti-tumor, anti-angiogenic and anti-proliferative activity. The experimental part of this article describes the effects of BR biosynthetic precursors on prostate cancer cells. The experiments were performed with LNCaP and DU-145 prostate cancer cell lines. These were cultivated and treated with tested BRs in different concentrations and time intervals. The tested compounds were found to affect cell viability, nuclear receptor expression, cell cycle and apoptosis in the tumor cells. IC50 concentrations were determined based on MTT test and the two most active compounds (cathasterone and 6-oxocampestanol) were used in the next experiments. Cathasterone was the most effective of all tested compounds and effectively inhibited integrity of cell spheres. It was found that both BRs had no significant effect on the cell cycle in LNCaP at IC50 concentration, while in DU-145 a significant block in G0/G1 phase after the BR treatment was observed. The effect of BRs on the nuclear steroid receptors was manifested by changes in their expression and localization. BRs demonstrated their significant effect on prostate cancer cells and the compounds have potential used in anticancer drug research and cancer treatment.


Assuntos
Antineoplásicos/farmacologia , Brassinosteroides/farmacologia , Receptores de Esteroides/metabolismo , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Masculino , Neoplasias da Próstata/tratamento farmacológico
8.
Biomolecules ; 11(1)2020 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-33383794

RESUMO

Plants have developed various acclimation strategies in order to counteract the negative effects of abiotic stresses (including temperature stress), and biological membranes are important elements in these strategies. Brassinosteroids (BR) are plant steroid hormones that regulate plant growth and development and modulate their reaction against many environmental stresses including temperature stress, but their role in modifying the properties of the biological membrane is poorly known. In this paper, we characterise the molecular dynamics of chloroplast membranes that had been isolated from wild-type and a BR-deficient barley mutant that had been acclimated to low and high temperatures in order to enrich the knowledge about the role of BR as regulators of the dynamics of the photosynthetic membranes. The molecular dynamics of the membranes was investigated using electron paramagnetic resonance (EPR) spectroscopy in both a hydrophilic and hydrophobic area of the membranes. The content of BR was determined, and other important membrane components that affect their molecular dynamics such as chlorophylls, carotenoids and fatty acids in these membranes were also determined. The chloroplast membranes of the BR-mutant had a higher degree of rigidification than the membranes of the wild type. In the hydrophilic area, the most visible differences were observed in plants that had been grown at 20 °C, whereas in the hydrophobic core, they were visible at both 20 and 5 °C. There were no differences in the molecular dynamics of the studied membranes in the chloroplast membranes that had been isolated from plants that had been grown at 27 °C. The role of BR in regulating the molecular dynamics of the photosynthetic membranes will be discussed against the background of an analysis of the photosynthetic pigments and fatty acid composition in the chloroplasts.


Assuntos
Brassinosteroides/metabolismo , Cloroplastos/metabolismo , Hordeum/fisiologia , Aclimatação , Cloroplastos/genética , Resposta ao Choque Frio , Resposta ao Choque Térmico , Hordeum/genética , Simulação de Dinâmica Molecular , Mutação , Fotossíntese
9.
Biomolecules ; 9(12)2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31835421

RESUMO

We have recently discovered that brassinosteroids (BRs) can inhibit the growth of etiolated pea seedlings dose-dependently in a similar manner to the 'triple response' induced by ethylene. We demonstrate here that the growth inhibition of etiolated pea shoots strongly correlates with increases in ethylene production, which also responds dose-dependently to applied BRs. We assessed the biological activities of two natural BRs on pea seedlings, which are excellent material as they grow rapidly, and respond both linearly and uni-phasically to applied BRs. We then compared the BRs' inhibitory effects on growth, and induction of ethylene and ACC (1-aminocyclopropane-1-carboxylic acid) production, to those of representatives of other phytohormone classes (cytokinins, auxins, and gibberellins). Auxin induced ca. 50-fold weaker responses in etiolated pea seedlings than brassinolide, and the other phytohormones induced much weaker (or opposite) responses. Following the optimization of conditions for determining ethylene production after BR treatment, we found a positive correlation between BR bioactivity and ethylene production. Finally, we optimized conditions for pea growth responses and developed a new, highly sensitive, and convenient bioassay for BR activity.


Assuntos
Brassinosteroides/farmacologia , Etilenos/metabolismo , Ervilhas/efeitos dos fármacos , Aminoácidos Cíclicos/metabolismo , Bioensaio/métodos , Inibidores do Crescimento/farmacologia , Ácidos Indolacéticos/farmacologia , Ervilhas/crescimento & desenvolvimento , Ervilhas/metabolismo , Reguladores de Crescimento de Plantas/farmacocinética , Reguladores de Crescimento de Plantas/farmacologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
10.
Front Plant Sci ; 10: 450, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31031786

RESUMO

Soil salinity is severely affecting crop productivity in many countries, particularly in the Mediterranean area. To evaluate early plant responses to increased salinity and characterize tolerance markers, three important Brassica crops - Chinese cabbage (Brassica rapa ssp. pekinensis), white cabbage (B. oleracea var. capitata) and kale (B. oleracea var. acephala) were subjected to short-term (24 h) salt stress by exposing them to NaCl at concentrations of 50, 100, or 200 mM. Physiological (root growth, photosynthetic performance parameters, and Na+/K+ ratio) and biochemical parameters (proline content and lipid peroxidation as indicated by malondialdehyde, MDA, levels) in the plants' roots and leaves were then measured. Photosynthetic parameters such as the total performance index PItotal (describing the overall efficiency of PSI, PSII and the intersystem electron transport chain) appeared to be the most salinity-sensitive parameter and informative stress marker. This parameter was decreased more strongly in Chinese cabbage than in white cabbage and kale. It indicated that salinity reduced the capacity of the photosynthetic system for efficient energy conversion, particularly in Chinese cabbage. In parallel with the photosynthetic impairments, the Na+/K+ ratio was highest in Chinese cabbage leaves and lowest in kale leaves while kale root is able to keep high Na+/K+ ratio without a significant increase in MDA. Thus Na+/K+ ratio, high in root and low in leaves accompanying with low MDA level is an informative marker of salinity tolerance. The crops' tolerance was positively correlated with levels of the stress hormone abscisic acid (ABA) and negatively correlated with levels of jasmonic acid (JA), and jasmonoyl-L-isoleucine (JA-Ile). Furthermore, salinity induced contrasting changes in levels of the growth-promoting hormones brassinosteroids (BRs). The crop's tolerance was positively correlated with levels of BR precursor typhasterol while negatively with the active BR brassinolide. Principal Component Analysis revealed correlations in observed changes in phytohormones, biochemical, and physiological parameters. Overall, the results show that kale is the most tolerant of the three species and Chinese cabbage the most sensitive to salt stress, and provide holistic indications of the spectrum of tolerance mechanisms involved.

11.
Plant Physiol Biochem ; 139: 215-228, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30908973

RESUMO

The purpose of experiments was to describe the alterations of content of steroid regulators (brassinosteroids, progesterone) during cold hardening of winter wheat. Further we studied physiological and biochemical changes induced by these steroids in cold hardened winter wheat together with estimation of plant frost tolerance. The endogenous brassinosteroid content was elevated in winter wheat during cold hardening while level of progesterone was lowered. A higher content of brassinosteroids (but not progesterone) was connected to better frost tolerance of winter wheat cultivars. Plant supplementation with brassinosteroid (24-epibrassinolide) and progesterone before cold hardening reduced frost damage. Tests with the inhibitors of the biosynthesis of brassinosteroids and progesterone suggested that these steroids are one of players in regulating the antioxidant system in winter wheat during cold hardening. Their role in regulating the expression of Rubisco or the Rubisco activase gene was less clear. Steroid regulators did not affect the content of the stress hormone ABA. Model studies of the membranes, made on a Langmuir bath, showed an increase in the value of the parameter describing differences in membrane compressibility (resulting from stronger interactions among the molecules in the monolayers). This suggests that 24-epibrassinolide and progesterone enter into the lipid layer and - in a similar way to sterols - stabilise the interaction among lipids. It may be significant step for better frost tolerance. The use of steroid regulators (especially brassinosteroids) as agrochemicals improving frost tolerance of winter cereals will be discussed.


Assuntos
Triticum/metabolismo , Temperatura Baixa , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Progesterona/metabolismo , Ribulose-Bifosfato Carboxilase/metabolismo , Triticum/genética
12.
Plant Physiol Biochem ; 137: 84-92, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30769236

RESUMO

This study focused on the idea that the toxic effect of zearalenone (ZEA) and the protective actions of the brassinosteroid - 24-epibrassinolide (EBR) as well as selenium are dependent on its accumulation in chloroplasts to a high degree. These organelles were isolated from the leaves of oxidative stress-sensitive and stress-tolerant wheat cultivars that had been grown from grains that had been incubated in a solution of ZEA (30 µM), Na2SeO4 (Se, 10 µM), EBR (0.1 µM) or in a mixture of ZEA with Se or EBR. Ultra-high performance liquid chromatography techniques indicated that ZEA was adsorbed in higher amounts in the chloroplasts in the sensitive rather than tolerant cultivar. Although the brassinosteroids and Se were also accumulated in the chloroplasts, higher levels were only found in the tolerant cultivar. The application of EBR increased the homocastasterone content, especially in the chloroplasts of the tolerant plant and after the addition of ZEA. The presence of both protectants caused a decrease in the ZEA content in studied organelles and resulted in diminishing of the oxidative stress (i.e. changes in the activity of the antioxidative enzymes). Moreover, a recovery of photosystem II and decrease in the negative impact of ZEN on Hsp90 transcript accumulation was observed in plants.


Assuntos
Brassinosteroides/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Selênio/farmacologia , Esteroides Heterocíclicos/farmacologia , Triticum/efeitos dos fármacos , Zearalenona/toxicidade , Antioxidantes/metabolismo , Brassinosteroides/metabolismo , Brassinosteroides/farmacocinética , Carotenoides/metabolismo , Clorofila A/metabolismo , Cloroplastos/efeitos dos fármacos , Enzimas/metabolismo , Proteínas de Choque Térmico HSP90/genética , Proteínas de Plantas/genética , Selênio/farmacocinética , Esteroides Heterocíclicos/farmacocinética , Triticum/metabolismo , Zearalenona/farmacocinética
13.
J Plant Physiol ; 232: 107-114, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30537597

RESUMO

Although structurally simple, viroids can trigger numerous changes in host plants and cause loss of yield in agronomically important crops. This study investigated changes in the endogenous status of phytohormones and antioxidant enzyme activity in Solanum tuberosum cv. Désirée in response to Potato spindle tuber viroid (PSTVd) infection. Phytohormone analysis showed that the content of endogenous jasmonic acid (JA) and its precursor cis-OPDA significantly increased in leaves, while the content of castasterone (CS) increased in both leaves and tubers of systemically infected plants compared to mock-inoculated control plants at 8 weeks post-inoculation. The indole-3-acetic acid content moderately increased only in tubers, while no differences in salicylic acid and abscisic acid content were observed between infected and control plants. Changes in endogenous phytohormone content were associated with upregulated expression of genes involved in the biosynthesis of JA and brassinosteroids, and the metabolism of auxins. Additionally, PSTVd infection provoked overproduction of hydrogen peroxide, which coincided with increased activity of guaiacol peroxidase in leaves and ascorbate peroxidase in potato tubers. The activity of catalase decreased in leaves, while superoxide dismutase activity remained steady regardless of the treatment and organ type. Total ascorbate and glutathione did not change significantly, although a shift towards oxidized forms was observed. Results suggest the existence of organ-specific differences in phytohormone and antioxidative responses in potato upon PSTVd infection. Possible effects of the observed changes on symptom development are discussed.


Assuntos
Doenças das Plantas/virologia , Reguladores de Crescimento de Plantas/metabolismo , Solanum tuberosum/fisiologia , Viroides/metabolismo , Antioxidantes/metabolismo , Brassinosteroides/metabolismo , Clorofila/metabolismo , Colestanóis/metabolismo , Ciclopentanos/metabolismo , Ácidos Indolacéticos/metabolismo , Oxilipinas/metabolismo , Folhas de Planta/metabolismo , Tubérculos/metabolismo , Solanum tuberosum/metabolismo , Solanum tuberosum/virologia
14.
Int J Mol Sci ; 19(10)2018 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-30360451

RESUMO

Plant hormones through signaling networks mutually regulate several signaling and metabolic systems essential for both plant development and plant responses to different environmental stresses. Extensive research has enabled the main effects of all known phytohormones classes to be identified. Therefore, it is now possible to investigate the interesting topic of plant hormonal crosstalk more fully. In this review, we focus on the role of brassinosteroids and ethylene during plant growth and development especially flowering, ripening of fruits, apical hook development, and root and shoot growth. As well as it summarizes their interaction during various abiotic stress conditions.


Assuntos
Brassinosteroides/metabolismo , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Desenvolvimento Vegetal/fisiologia , Transdução de Sinais/fisiologia
15.
J Exp Bot ; 69(3): 441-454, 2018 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29294075

RESUMO

Cytokinins comprise a group of phytohormones with an organ-specific mode of action. Although the mechanisms controlling the complex networks of cytokinin metabolism are partially known, the role of individual cytokinin types in the maintenance of cytokinin homeostasis remains unclear. Utilizing the overproduction of single-chain Fv antibodies selected for their ability to bind trans-zeatin riboside and targeted to the endoplasmic reticulum, we post-synthetically modulated cytokinin ribosides, the proposed transport forms of cytokinins. We observed asymmetric activity of cytokinin biosynthetic genes and cytokinin distribution in wild-type tobacco seedlings with higher cytokinin abundance in the root than in the shoot. Antibody-mediated modulation of cytokinin ribosides further enhanced the relative cytokinin abundance in the roots and induced cytokinin-related phenotypes in an organ-specific manner. The activity of cytokinin oxidase/dehydrogenase in the roots was strongly up-regulated in response to antibody-mediated formation of the cytokinin pool in the endoplasmic reticulum. However, we only detected a slight decrease in the root cytokinin levels. In contrast, a significant decrease of cytokinins occurred in the shoot. We suggest the roots as the main site of cytokinin biosynthesis in tobacco seedlings. Conversely, cytokinin levels in the shoot seem to depend largely on long-range transport of cytokinin ribosides from the root and their subsequent metabolic activation.


Assuntos
Citocininas/fisiologia , Homeostase , Isopenteniladenosina/análogos & derivados , Fenótipo , Reguladores de Crescimento de Plantas/fisiologia , Tabaco/fisiologia , Isopenteniladenosina/metabolismo , Planticorpos/fisiologia , Plântula/fisiologia
16.
J Steroid Biochem Mol Biol ; 178: 263-271, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29307714

RESUMO

We report the synthesis and detailed biological study of the synthetic brassinosteroid analog 2α,3α-dihydroxy-6-oxo-5α-androstan-17ß-yl N-(tert-butoxycarbonyl)-D,L-valinate (BR4848). The panel of cancer cell lines was used for characterization of its antiproliferative activity, yet had no adverse effects in normal human fibroblasts. In HeLa cells, BR4848-induced apoptosis was accompanied by increase of apoptotic subG1 cells, PARP-1 and caspase-7 fragmentation, downregulation of Bcl-2 and Mcl-1, an increase in caspase activity and G2/M phase cell cycle arrest. Antiproliferative properties of BR4848 were exhibited by inhibition of phosphorylation of Akt, Erk1/2 and FAK. Furthermore, the developed analog exhibited in vitro antiangiogenic activity in human umbilical vein endothelial cells (HUVECs). BR4848-induced apoptosis accompanied with G2/M arrest was detected in endothelial cells. BR4848 also inhibited adhesion, tube formation and migration of endothelial cells by inhibition of FAK, Erk 1/2, CDK5, VEGFR2, TNFα-stimulated production of IL-6, angiopoietin-2 and Jagged1. Finally, BR4848 did not modulate the activity nor nuclear translocation of any of the steroid receptors (ERα, ERß, AR, MR and PR) included in reporter cell-based assays, which excludes the genomic activity of steroid receptors as a contributing factor to the observed biological activities of BR4848.


Assuntos
Inibidores da Angiogênese/farmacologia , Apoptose/efeitos dos fármacos , Brassinosteroides/farmacologia , Células Endoteliais da Veia Umbilical Humana/patologia , Neoplasias/patologia , Neovascularização Patológica/prevenção & controle , Inibidores da Angiogênese/química , Brassinosteroides/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Técnicas In Vitro , Neoplasias/irrigação sanguínea , Neoplasias/tratamento farmacológico , Neovascularização Patológica/patologia , Fosforilação , Transdução de Sinais , Células Tumorais Cultivadas
17.
Steroids ; 127: 46-55, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28837783

RESUMO

A series of phenyl analogues of brassinosteroids was prepared via alkene cross-metathesis using commercially available styrenes and 24-nor-5α-chola-2,22-dien-6-one. All derivatives were successfully docked into the active site of BRI1 using AutoDock Vina. Plant growth promoting activity was measured using the pea inhibition biotest and Arabidopsis root sensitivity assay and then was compared with naturally occuring brassinosteroids. Differences in the production of plant hormone ethylene were also observed in etiolated pea seedlings after treatment with the new and also five known brassinosteroid phenyl analogues. Antiproliferative activity was also studied using normal human fibroblast and human cancer cell lines.


Assuntos
Alcenos/química , Brassinosteroides/síntese química , Brassinosteroides/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Brassinosteroides/química , Brassinosteroides/metabolismo , Domínio Catalítico , Técnicas de Química Sintética , Simulação de Acoplamento Molecular , Ervilhas/efeitos dos fármacos , Ervilhas/crescimento & desenvolvimento , Proteínas Quinases/química , Proteínas Quinases/metabolismo
18.
Talanta ; 170: 432-440, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28501193

RESUMO

Brassinosteroids (BRs) are plant-specific steroid hormones that play essential roles in the regulation of many important physiological processes in plant life. Their extremely low concentrations (~pmoles/g FW) in plant tissue and huge differences in polarity of individual members within the BR family hamper their detection and quantification. To address this problem, an immunoaffinity sorbent with broad specificity and high capacity for different BR metabolites containing a monoclonal antibody (mAb) against a BR spacer (20S)-2α,3α-dihydroxy-7-oxa-7α-homo-5α-pregnane-6-one-20 carboxylic acid (BR4812) was used for the rapid and highly selective isolation of endogenous BRs containing a 2α,3α-diol in ring A from minute plant samples. This enrichment procedure was successfully applied as a sample preparation method prior to quantitative analysis of BRs in real plant tissues by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Use of immunoaffinity chromatography (IAC) increased the sensitivity of the UHPLC-MS/MS analysis owing to improvements in the BR signal-to-noise ratio (S/N) and matrix factor (MF). Although MF values of BRs analyzed in classical samples ranged from 8.9% to 47.4%, MF values for the IAC purified samples reached 44.5-96.6%. Thus, the developed IAC-UHPLC-MS/MS approach was shown to be a simple, robust, effective and extremely fast procedure requiring minute amounts of plant samples suitable for the quantitative profiling of many BR metabolites, helping to overcome the major problems associated with their determination in very complex plant matrices.


Assuntos
Brassica napus/química , Brassinosteroides/análise , Cromatografia de Afinidade/métodos , Reguladores de Crescimento de Plantas/análise , Espectrometria de Massas em Tandem/métodos , Anticorpos Imobilizados/química , Brassinosteroides/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Imunoadsorventes/química , Extratos Vegetais/química , Reguladores de Crescimento de Plantas/isolamento & purificação
19.
Plant J ; 89(5): 1065-1075, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27943492

RESUMO

Cytokinins (CKs) are pivotal plant hormones that have crucial roles in plant growth and development. However, their isolation and quantification are usually challenging because of their extremely low levels in plant tissues (pmol g-1 fresh weight). We have developed a simple microscale magnetic immunoaffinity-based method for selective one-step isolation of CKs from very small amounts of plant tissue (less than 0.1 mg fresh weight). The capacity of the immunosorbent and the effect of the complex plant matrix on the yield of the rapid one-step purification were tested using a wide range of CK concentrations. The total recovery range of the new microscale isolation procedure was found to be 30-80% depending on individual CKs. Immunoaffinity extraction using group-specific monoclonal CK antibodies immobilized onto magnetic microparticles was combined with a highly sensitive ultrafast mass spectrometry-based method with a detection limit close to one attomole. This combined approach allowed metabolic profiling of a wide range of naturally occurring CKs (bases, ribosides and N9 -glucosides) in 1.0-mm sections of the Arabidopsis thaliana root meristematic zone. The magnetic immunoaffinity separation method was shown to be a simple and extremely fast procedure requiring minimal amounts of plant tissue.


Assuntos
Arabidopsis/química , Citocininas/isolamento & purificação , Nanopartículas de Magnetita , Reguladores de Crescimento de Plantas/isolamento & purificação , Raízes de Plantas/química , Citocininas/química , Reguladores de Crescimento de Plantas/química
20.
Front Plant Sci ; 7: 1824, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27994612

RESUMO

Brassinosteroids (BRs) are a class of steroid phytohormones, which regulate various processes of morphogenesis and physiology-from seed development to regulation of flowering and senescence. An accumulating body of evidence indicates that BRs take part in regulation of physiological reactions to various stress conditions, including drought. Many of the physiological functions of BRs are regulated by a complicated, and not fully elucidated network of interactions with metabolic pathways of other phytohormones. Therefore, the aim of this study was to characterize phytohormonal homeostasis in barley (Hordeum vulgare) in reaction to drought and validate role of BRs in regulation of this process. Material of this study included the barley cultivar "Bowman" and five Near-Isogenic Lines (NILs) representing characterized semi-dwarf mutants of several genes encoding enzymes participating in BR biosynthesis and signaling. Analysis of endogenous BRs concentrations in these NILs confirmed that their phenotypes result from abnormalities in BR metabolism. In general, concentrations of 18 compounds, representing various classes of phytohormones, including brassinosteroids, auxins, cytokinins, gibberellins, abscisic acid, salicylic acid and jasmonic acid were analyzed under control and drought conditions in the "Bowman" cultivar and the BR-deficient NILs. Drought induced a significant increase in accumulation of the biologically active form of BRs-castasterone in all analyzed genotypes. Another biologically active form of BRs-24-epi-brassinolide-was identified in one, BR-insensitive NIL under normal condition, but its accumulation was drought-induced in all analyzed genotypes. Analysis of concentration profiles of several compounds representing gibberellins allowed an insight into the BR-dependent regulation of gibberellin biosynthesis. The concentration of the gibberellic acid GA7 was significantly lower in all NILs when compared with the "Bowman" cultivar, indicating that GA7 biosynthesis represents an enzymatic step at which the stimulating effect of BRs on gibberellin biosynthesis occurs. Moreover, the accumulation of GA7 is significantly induced by drought in all the genotypes. Biosynthesis of jasmonic acid is also a BR-dependent process, as all the NILs accumulated much lower concentrations of this hormone when compared with the "Bowman" cultivar under normal condition, however the accumulation of jasmonic acid, abscisic acid and salicylic acid were significantly stimulated by drought.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...