RESUMO
Rubber (Hevea brasiliensis) is a latex-producing plant that often encounters mechanical wounding, as well as pathogen and pest attacks through wound sites during and after tapping. Terpenoids play an important role in the ecological interactions of many plant species, and their diversity is mainly generated by enzymes known as terpene synthases (TPS). In this study, one cDNA sequence encoding a putative terpene synthase, HbTPS20, was obtained from the bark tissues of H. brasiliensis. The encoded protein contains 610 amino acids with a putative N-terminal plastid transit peptide of approximately 70 residues. It belongs to the TPS-b subfamily. Further phylogenetic analysis showed that HbTPS20 formed a separate branch that diverged from the progenitor of all other potentially functional terpene synthases of the rubber TPS-b subfamily. The truncated HbTPS20 without the signal peptide coding sequence was successfully expressed in E. coli and in vitro enzymatic assays with geranyl diphosphate (GPP) or neryl diphosphate (NPP) as a substrate defined HbTPS20 as an active linalool synthase (HbLIS) with the ability to produce linalool as the principal product. RT-qPCR analysis showed that the highest transcript levels of HbTPS20 were found in barks, and this gene was expressed at 2.26- and 250-fold greater levels in the bark tissues of wounded and MeJA-treated plants, respectively, than in those of the control plants. This indicates that this gene may be involved in the induced stress responses of rubber.
Assuntos
Hevea , Borracha , Borracha/metabolismo , Hevea/genética , Filogenia , Casca de Planta/metabolismo , Escherichia coli , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
Stored water in inner tissues influences the plant water economy, which might be particularly relevant for trees facing increasing dry conditions due to climate change. We studied the water storage in the inner bark and the sapwood of Araucaria araucana (Molina) K. Koch. This species has an extremely thick inner bark and thus it can be used as a model system to assess the impact of internal water storage on plant water balance. Specifically, we analyzed the water circulation pathways in and out of the elastic water storages by using simultaneously frequency domain moisture sensors and dendrometers inserted in the inner bark and in the sapwood, and sap flow determinations during the dry season. The daily patterns of water content and expansion and contraction of the stem tissues were similar to the sap flow pattern. The whole-stem water content and diameter increased in the morning and decreased in the afternoon, contrary to the typical pattern observed in most tree species. An osmotic gradient favoring the water influx from sapwood to inner bark was observed in the morning. There were no lags in the onset of sap flow between different stem heights at the time that recharge of reservoirs occurred. Sap flow at 6 m height was higher than basal sap flow in the afternoon, when the sapwood water content started to decline followed by the water content of the inner bark. Inner bark and sapwood contributed 5-11% to total daily transpiration, allowing the maintenance of high water potentials in the dry season. Our results suggest that the stored water in the stems, the atypical dynamic of recharge and discharge of water from reservoirs and the high tissue capacitance may make an important contribution to the survival of A. araucana during drought periods by maintaining the water balance.
Assuntos
Araucaria araucana , Água , Água/metabolismo , Secas , Casca de Planta/metabolismo , Transpiração Vegetal , Ritmo Circadiano , Árvores/metabolismo , Caules de Planta/metabolismoRESUMO
A phytochemical investigation of cytotoxic extract and fractions of Cnidoscolus quercifolius Pohl led to isolation of five terpenoids, including three lupane-type triterpenes (1-3) and two bis-nor-diterpenes (4-5). Compounds 4 (phyllacanthone) and 5 (favelanone) are commonly found in this species and have unique chemical structure. Although their cytotoxic activity against cancer cells has been previously reported, the anticancer potential of these molecules remains poorly explored. In this paper, the antimelanoma potential of phyllacanthone (PHY) was described for the first time. Cell viability assay showed a promising cytotoxic activity (IC50 = 40.9 µM) against chemoresistant human melanoma cells expressing the BRAF oncogenic mutation (A2058 cell line). After 72 h of treatment, PHY inhibited cell migration and induced apoptosis and cell cycle arrest (p < 0.05). Immunofluorescence assay showed that the pro-apoptotic effect of PHY is probably associated with tubulin depolymerization, resulting in cytoskeleton disruption of melanoma cells. Molecular docking investigation confirmed this hypothesis given that satisfactory interaction between PHY and tubulin was observed, particularly at the colchicine binding site. These results suggest PHY from C. quercifolius could be potential leader for the design of new antimelanoma drugs.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Diterpenos/química , Euphorbiaceae/química , Proteínas Proto-Oncogênicas B-raf/genética , Tubulina (Proteína)/metabolismo , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/metabolismo , Sítios de Ligação , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular , Colchicina/química , Colchicina/metabolismo , Diterpenos/metabolismo , Diterpenos/farmacologia , Euphorbiaceae/metabolismo , Humanos , Melanoma/metabolismo , Melanoma/patologia , Simulação de Acoplamento Molecular , Mutação , Casca de Planta/química , Casca de Planta/metabolismo , Extratos Vegetais/química , Proteínas Proto-Oncogênicas B-raf/metabolismo , Tubulina (Proteína)/químicaRESUMO
BACKGROUND: French maritime pine bark (Pinus pinaster) extract (PBE), the registered trade name of which is Pycnogenol® , has been studied for its depigmenting action due to its antioxidant, anti-inflammatory, and anti-melanogenic activity. However, the mechanisms through which PBE are still not fully clear. OBJECTIVE: Evaluate the impact of PBE on four in vitro parameters closely associated with cutaneous pigmentation, including melanin synthesis, tyrosinase activity, endothelin-1 (ED1), and production of peroxisome proliferator-activated receptor α, δ, and γ (PPAR α, δ, and γ), by studying the modulation of action of ultraviolet radiation A (UVA)/ultraviolet radiation B (UVB), infrared-A (IR-A), visible light (VL), and association of UVA/UVB, IR-A, and VL (ASS). METHODS: Human melanocytes were incubated in a dry extract solution of PBE, exposed to UVA/UVB, IR-A, VL, and ASS for subsequent quantification of melanin, ED1, and PPAR α, δ, and γ. The effects of PBE on inhibition of tyrosinase activity were also performed by monophenolase activity assay. RESULTS: UVA/UVB, IR-A, VL, and ASS radiation caused significant increases in the synthesis of melanin, ED1, and PPAR α, δ, and γ when compared to baseline control. However, PBE significantly reduced the production of melanin, ED1, and PPAR α, δ, and γ, as well as reducing about 66.5% of the tyrosinase activity. CONCLUSIONS: PBE reduces in vitro melanin production by downregulating tyrosinase and reducing pigmentation-related mediators, such as ED1 and PPAR α, δ, and γ, therefore contributing to the inhibition of pathways associated with skin hyperpigmentation.
Assuntos
Melaninas , Monofenol Mono-Oxigenase , Endotelina-1/metabolismo , Endotelina-1/farmacologia , Humanos , Melanócitos/metabolismo , Monofenol Mono-Oxigenase/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/farmacologia , Casca de Planta/metabolismo , Extratos Vegetais/metabolismo , Extratos Vegetais/farmacologia , Raios UltravioletaRESUMO
Amphipterygium adstringens (cuachalalate) contains anacardic acids (AAs) such as 6-pentadecyl salicylic acid (6SA) that show immunomodulatory and antitumor activity with minimal or no secondary adverse effects. By contrast, most chemotherapeutic agents, such as 5-fluorouracil (5-FU) and carboplatin (CbPt), induce myelosuppression and leukopenia. Here, we investigated the myeloprotective and antineoplastic potential of an AA extract or the 6SA as monotherapy or in combination with commonly used chemotherapeutic agents (5-FU and CbPt) to determine the cytoprotective action of 6SA on immune cells. Treatment of Balb/c breast tumor-bearing female mice with an AA mixture or 6SA did not induce the myelosuppression or leukopenia observed with 5-FU and CbPt. The co-administration of AA mixture or isolated 6SA with 5-FU or CbPt reduced the apoptosis of circulating blood cells and bone marrow cells. Treatment of 4T1 breast tumor-bearing mice with the AA mixture or 6SA reduced tumor growth and lung metastasis and increased the survival rate compared with monotherapies. An increased effect was observed in tumor reduction with the combination of 6SA and CbPt. In conclusion, AAs have important myeloprotective and antineoplastic effects, and they can improve the efficiency of chemotherapeutics, thereby protecting the organism against the toxic effects of drugs such as 5-FU and CbPt.
Assuntos
Ácidos Anacárdicos/química , Carboplatina/farmacologia , Fluoruracila/farmacologia , Neoplasias Mamárias Experimentais/tratamento farmacológico , Anacardiaceae , Ácidos Anacárdicos/farmacologia , Animais , Antineoplásicos/farmacologia , Apoptose , Células da Medula Óssea/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Citoproteção , Modelos Animais de Doenças , Feminino , Hexanos/química , Leucócitos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Metástase Neoplásica , Casca de Planta/metabolismoRESUMO
Non-structural carbohydrates (NSC) are crucial for forest resilience, but little is known regarding the role of bark in NSC storage. However, bark's abundance in woody stems and its large living fraction make it potentially key for NSC storage. We quantified total NSC, soluble sugar (SS) and starch concentrations in the most living region of bark (inner bark, IB), and sapwood of twigs, trunks and roots of 45 woody species from three contrasting tropical climates spanning global extremes of bark diversity and wide phylogenetic diversity. NSC concentrations were similar (total NSC, starch) or higher (SS) in IB than wood, with concentrations co-varying strongly. NSC concentrations varied widely across organs and species within communities and were not significantly affected by climate, leaf habit or the presence of photosynthetic bark. Starch concentration tended to increase with density, but only in wood. IB contributed substantially to NSC storage, accounting for 17-36% of total NSC, 23-47% of SS and 15-33% of starch pools. Further examination of the drivers of variation in IB NSC concentration, and taking into account the substantial contribution of IB to NSC pools, will be crucial to understand the role of storage in plant environmental adaptation.
Assuntos
Metabolismo dos Carboidratos , Casca de Planta/metabolismo , Árvores/metabolismo , Bursera/metabolismo , Carboidratos/análise , Diospyros/metabolismo , Lamiaceae/metabolismo , Casca de Planta/anatomia & histologia , Casca de Planta/química , Clima Tropical , Água/metabolismo , Madeira/metabolismoRESUMO
BACKGROUND: Sucrose (Suc), as the precursor molecule for rubber biosynthesis in Hevea brasiliensis, is transported via phloem-mediated long-distance transport from leaves to laticifers in trunk bark, where latex (cytoplasm of laticifers) is tapped for rubber. In our previous report, six Suc transporter (SUT) genes have been cloned in Hevea tree, among which HbSUT3 is verified to play an active role in Suc loading to the laticifers. In this study, another latex-abundant SUT isoform, HbSUT5, with expressions only inferior to HbSUT3 was characterized especially for its roles in latex production. RESULTS: Both phylogenetic analysis and subcellular localization identify HbSUT5 as a tonoplast-localized SUT protein under the SUT4-clade (=type III). Suc uptake assay in baker's yeast reveals HbSUT5 to be a typical Suc-H+ symporter, but its high affinity for Suc (Km = 2.03 mM at pH 5.5) and the similar efficiency in transporting both Suc and maltose making it a peculiar SUT under the SUT4-clade. At the transcript level, HbSUT5 is abundantly and preferentially expressed in Hevea barks. The transcripts of HbSUT5 are conspicuously decreased both in Hevea latex and bark by two yield-stimulating treatments of tapping and ethephon, the patterns of which are contrary to HbSUT3. Under the ethephon treatment, the Suc level in latex cytosol decreases significantly, but that in latex lutoids (polydispersed vacuoles) changes little, suggesting a role of the decreased HbSUT5 expression in Suc compartmentalization in the lutoids and thus enhancing the Suc sink strength in laticifers. CONCLUSIONS: Our findings provide insights into the roles of a vacuolar sucrose transporter, HbSUT5, in Suc exchange between lutoids and cytosol in rubber-producing laticifers.
Assuntos
Hevea/metabolismo , Látex/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Plantas/metabolismo , Sacarose/metabolismo , Citoplasma/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Hevea/genética , Floema/metabolismo , Casca de Planta/metabolismo , Regiões Promotoras Genéticas , Saccharomyces cerevisiae , Vacúolos/metabolismoRESUMO
Magnetite nanoparticles use for the remediation of toxic metal ions. Therefore, the scope of green synthesis of magnetite nanoparticles from Hevea bark extract, and application of these particles for the environmental remediation of Cd and Na tested. Mixing of 10.0 mL each bark extract (1.0 g in 25.0 mL H2O) and iron solution (10.0 mM FeCl3 and 5.0 mM FeCl2) resulted formation of semicrystalline magnetite nanoparticles having magnetic saturation at 104 G. The particles characterized with the help of scanning electron microscopy, energy dispersive spectroscopy, Uv-vis spectroscopy, vibrating sample magnetometry, powder X-Ray diffraction, Fourier-transform infrared spectroscopy, and differential thermal analysis coupled with thermogravimetry. The phytochemicals responsible for priming and coating of nanoparticle were phenolics, especially benzoic acid derivatives. Adsorption of metal ions to nanoparticles followed pseudo-second-order model. Maximum Cd and Na adsorption capacity were 37.03 and 3.95 mg g-1 respectively. The difference in Cd and Na adsorption capacity was the result of multilayer and monolayer adsorption processes respectively. Highest metal ion adsorption occurred at temperature 10.0-20.0 °C and pH 6.0. Metal adsorption property of the nanoparticles decreased the accumulation of Cd and Na in rice plants. The plant growth promotion effects of nanoparticles explained regarding biomass, osmolyte content, and oxidative stress tolerance. Therefore, the nanoparticles produced in the study can use as a magnetically separable nano sorbent of metal ions as well as ameliorant of metal stress in rice.
Assuntos
Cádmio/química , Hevea/metabolismo , Nanopartículas de Magnetita/química , Metais/toxicidade , Oryza/metabolismo , Casca de Planta/metabolismo , Sódio/química , Poluentes Químicos da Água/toxicidade , AdsorçãoRESUMO
Tapping Panel Dryness (TPD) affects latex production in Hevea brasiliensis. This physiological syndrome involves the agglutination of rubber particles, which leads to partial or complete cessation of latex flow. Latex harvesting consists in tapping soft bark. Ethephon can be applied to stimulate latex flow and its regeneration in laticifers. Several studies have reported transcriptome changes in bark tissues. This study is the first report on deep RNA sequencing of latex to compare the effect of ethephon stimulation and TPD severity. Trees were carefully selected for paired-end sequencing using an Illumina HiSeq 2000. In all, 43 to 60 million reads were sequenced for each treatment in three biological replicates (slight TPD trees without ethephon stimulation, and slight and severe TPD trees with ethephon treatment). Differentially expressed genes were identified and annotated, giving 8,111 and 728 in response to ethephon in slight TPD trees and in ethephon-induced severe TPD trees, respectively. A biological network of responses to ethephon and TPD highlighted the major influence of metabolic processes and the response to stimulus, especially wounding and jasmonate depression in TPD-affected trees induced by ethephon stimulation.
Assuntos
Hevea/genética , Compostos Organofosforados/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Hevea/metabolismo , Látex/biossíntese , Casca de Planta/genética , Casca de Planta/metabolismo , Doenças das Plantas/genética , Análise de Componente Principal , RNA de Plantas/química , RNA de Plantas/isolamento & purificação , RNA de Plantas/metabolismo , Análise de Sequência de RNARESUMO
BACKGROUND: Seasonal variation is presumed to play an important role in the regulation of tree growth, especially for Eucalyptus grandis, a fast-growing tree. This variation may induce changes in the whole tree at transcriptional, protein and metabolite levels. Bark represents an important group of tissues that protect trees from desiccation and pathogen attack, and it has been identified as potential feedstock for lignocellulosic derived biofuels. Despite the growing interest, little is known about the molecular mechanisms that regulates bark metabolism, particularly in tropical countries. RESULTS: In this study we report the changes observed in the primary metabolism of E. grandis bark during two contrasting seasons in Brazil, summer (wet) and winter (dry), through the combination of transcripts (RT-qPCR), proteome (2-DE gels) and metabolome (GC-MS) analysis, in an integrated manner. Twenty-four genes, involved in carbon metabolism, were analyzed in the two seasons. Eleven were up-regulated in summer, three were up-regulated in winter and ten did not show statistical differences in the expression pattern. The proteomic analysis using 2-DE gels showed 77 proteins expressing differences in abundance, with 38 spots up-regulated in summer and 37 in winter. Different metabolites significantly accumulated during winter. CONCLUSIONS: This study revealed a metabolic reconfiguration in the primary metabolism of E. grandis bark, triggered by seasonal variation. Transcripts and protein data suggests that during winter carbohydrate formation seems to be favored by tree metabolism. Glucose, fructose and sucrose accumulated at significant levels during the winter.