RESUMO
Phytochemical electrophiles are drawing significant attention due to their properties to modulate signaling pathways related to cellular homeostasis. The aim of this study was to develop new tools to examine the electrophilic activity in food and predict their beneficial effects on health. We developed a spectrophotometric assay based on the nitrobenzenethiol (NBT) reactivity, as a thiol-reactive nucleophile, to screen electrophiles in tomato fruits. The method is robust, simple, inexpensive, and could be applied to other types of food. We quantified the electrophile activity in a tomato collection and associated this activity with the pigment composition. Thus, we identified lycopene, ß- and γ-carotenes, 16 by-products of carotenoid oxidation and 18 unknown compounds as NBT-reactive by HPLC-MS/MS. The potential benefits of NBT-reactive compounds on health were evaluated in the in vivo model of C. elegans where they activated the SKN-1/Nrf2 pathway, evidencing the ability of electrophilic compounds to induce a biological response.
Assuntos
Proteínas de Caenorhabditis elegans , Solanum lycopersicum , Animais , Caenorhabditis elegans/genética , Proteínas de Ligação a DNA , Suplementos Nutricionais , Fator 2 Relacionado a NF-E2/genética , Espectrometria de Massas em Tandem , Fatores de TranscriçãoRESUMO
Tocochromanols constitute the different forms of vitamin E (VTE), essential components of the human diet, and display a high membrane protectant activity. By combining interval mapping and genome-wide association studies (GWAS), we unveiled the genetic determinants of tocochromanol accumulation in tomato (Solanum lycopersicum) fruits. To enhance the nutritional value of this highly consumed vegetable, we dissected the natural intraspecific variability of tocochromanols in tomato fruits and genetically engineered their biosynthetic pathway. These analyses allowed the identification of a total of 25 quantitative trait loci interspersed across the genome pinpointing the chorismate-tyrosine pathway as a regulatory hub controlling the supply of the aromatic head group for tocochromanol biosynthesis. To validate the link between the chorismate-tyrosine pathway and VTE, we engineered tomato plants to bypass the pathway at the arogenate branch point. Transgenic tomatoes showed moderate increments in tocopherols (up to approximately 20%) and a massive accumulation of tocotrienols (up to approximately 3400%). Gene expression analyses of these plants reveal a trade-off between VTE and natural variation in chorismate metabolism explained by transcriptional reprogramming of specific structural genes of the pathway. By restoring the accumulation of alpha-tocotrienols (α-t3) in fruits, the plants produced here are of high pharmacological and nutritional interest.
Assuntos
Ácido Corísmico/metabolismo , Solanum lycopersicum/metabolismo , Vitamina E/análise , Mapeamento Cromossômico , Frutas/química , Frutas/metabolismo , Genes de Plantas/genética , Engenharia Genética , Loci Gênicos , Variação Genética , Estudo de Associação Genômica Ampla , Solanum lycopersicum/química , Solanum lycopersicum/genética , Redes e Vias Metabólicas/genética , Plantas Geneticamente Modificadas , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Tirosina/metabolismo , Vitamina E/metabolismoRESUMO
Sucrose metabolism is important for most plants, both as the main source of carbon and via signaling mechanisms that have been proposed for this molecule. A cleaving enzyme, invertase (INV) channels sucrose into sink metabolism. Although acid soluble and insoluble invertases have been largely investigated, studies on the role of neutral invertases (A/N-INV) have lagged behind. Here, we identified a tomato A/N-INV encoding gene (NI6) co-localizing with a previously reported quantitative trait locus (QTL) largely affecting primary carbon metabolism in tomato. Of the eight A/N-INV genes identified in the tomato genome, NI6 mRNA is present in all organs, but its expression was higher in sink tissues (mainly roots and fruits). A NI6-GFP fusion protein localized to the cytosol of mesophyll cells. Tomato NI6-silenced plants showed impaired growth phenotype, delayed flowering and a dramatic reduction in fruit set. Global gene expression and metabolite profile analyses of these plants revealed that NI6 is not only essential for sugar metabolism, but also plays a signaling role in stress adaptation. We also identified major hubs, whose expression patterns were greatly affected by NI6 silencing; these hubs were within the signaling cascade that coordinates carbohydrate metabolism with growth and development in tomato.
Assuntos
Frutas/fisiologia , Solanum lycopersicum , beta-Frutofuranosidase , Citosol , Solanum lycopersicum/enzimologia , Solanum lycopersicum/genética , Sacarose , beta-Frutofuranosidase/genéticaRESUMO
BACKGROUND: Chlorogenic acid (CGA) is a polyphenol widely distributed in plants and plant-derived food with antioxidant and protective activities against cell stress. Caenorhabditis elegans is a model organism particularly useful for understanding the molecular and biochemical mechanisms associated with aging and stress in mammals. In C. elegans, CGA was shown to improve resistance to thermal, while the underlying mechanisms that lead to this effect require further understanding. PURPOSE: The present study was conducted to investigate the underlying molecular mechanisms behind CGA response conferring thermotolerance to C. elegans. METHODS AND RESULTS: Signaling pathways that could be involved in the CGA-induced thermotolerance were evaluated in C. elegans strains with loss-of-function mutation. CGA-induced thermotolerance required hypoxia-inducible factor HIF-1 but no insulin pathway. CGA exposition (1.4⯵M CGA for 18â¯h) before thermal stress treatment increased HIF-1 levels and activity. HIF-1 activation could be partly attributed to an increase in radical oxygen species and a decrease in superoxide dismutase activity. In addition, CGA exposition before thermal stress also increased autophagy just as hormetic heat condition (HHC), worms incubated at 36 °C for 1â¯h. RNAi experiments evidenced that autophagy was increased by CGA via HIF-1, heat-shock transcription factor HSF-1 and heat-shock protein HSP-16 and HSP-70. In contrast, autophagy induced by HHC only required HSF-1 and HSP-70. Moreover, suppression of autophagy induction showed the significance of this process for adapting C. elegans to cope with thermal stress. CONCLUSION: This study demonstrates that CGA-induced thermotolerance in C. elegans is mediated by HIF-1 and downstream, by HSF-1, HSPs and autophagy resembling HHC.
Assuntos
Autofagia/efeitos dos fármacos , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/efeitos dos fármacos , Ácido Clorogênico/farmacologia , Proteínas de Choque Térmico/metabolismo , Fatores de Transcrição/metabolismo , Animais , Antioxidantes/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/genética , Ácido Clorogênico/química , Proteínas de Choque Térmico/genética , Resposta ao Choque Térmico , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Termotolerância/efeitos dos fármacos , Fatores de Transcrição/genéticaRESUMO
Tocopherols are non-polar compounds synthesized in the plastids, which function as major antioxidants of the plant cells and are essential in the human diet. Both the intermediates and final products of the tocopherol biosynthetic pathway must cross plastid membranes to reach their sites of action. So far, no protein with tocopherol binding activity has been reported in plants. Here, we demonstrated that the tomato SlTBP protein is targeted to chloroplasts and able to bind α-tocopherol. SlTBP-knockdown tomato plants exhibited reduced levels of tocopherol in both leaves and fruits. Several tocopherol deficiency phenotypes were apparent in the transgenic lines, such as alterations in photosynthetic parameters, dramatic distortion of thylakoid membranes and significant variations in the lipid profile. These results, along with the altered expression of genes related to photosynthesis, and tetrapyrrole, lipid, isoprenoid, inositol/phosphoinositide and redox metabolism, suggest that SlTBP may act in conducting tocopherol (or its biosynthetic intermediates) between the plastid compartments and/or at the interface between chloroplast and endoplasmic reticulum membranes, affecting interorganellar lipid metabolism.
Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Plantas/metabolismo , Solanum lycopersicum/metabolismo , alfa-Tocoferol/metabolismo , Cloroplastos/metabolismo , Retículo Endoplasmático/metabolismo , Técnicas de Silenciamento de Genes , Metabolismo dos Lipídeos , Solanum lycopersicum/genética , Filogenia , Proteínas de Plantas/genética , Plastídeos/metabolismoRESUMO
BACKGROUND: The fruits of most commercial tomato cultivars (Solanum lycopersicum L.) are deficient in flavour. In contrast, traditional 'criollo' tomato varieties are appreciated for fruit of excellent organoleptic quality. Small farmers from the Andean valleys in Argentina have maintained their own tomato varieties, which were selected mainly for flavour. This work aims to correlate the chemical composition of the fruit with the sensory attributes of eight heirloom tomato varieties. The long-term goal is to identify potential candidate genes capable of altering the chemicals involved in flavour. RESULTS: A sensory analysis was conducted and the metabolomics of fruit were determined. The data revealed that defined tomato aroma and sourness correlated with citrate and several volatile organic compounds (VOC), such as α-terpineol, p-menth-1-en-9-al, linalool and 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (DMHEX), a novel volatile recently identified in tomato. Two sensory attributes - sweetness and a not-acidic taste - correlated with the characteristic tomato taste, and also with fructose, glucose, and two VOCs, benzaldehyde, and 2-methyl-2-octen-4-one. CONCLUSIONS: These data provide new evidence of the complex chemical combination that induced the flavour and aroma of the good-tasting 'criollo' tomato fruit. That is, the compounds that correlated with defined tomato aroma and acidic taste did not correlate with sweetness, or with characteristic tomato taste. © 2018 Society of Chemical Industry.
Assuntos
Solanum lycopersicum/química , Adulto , Argentina , Carotenoides/química , Carotenoides/metabolismo , Feminino , Aromatizantes/química , Aromatizantes/metabolismo , Frutas/química , Frutas/classificação , Frutas/economia , Frutas/metabolismo , Humanos , Solanum lycopersicum/classificação , Solanum lycopersicum/economia , Solanum lycopersicum/metabolismo , Masculino , Metaboloma , Pessoa de Meia-Idade , Odorantes/análise , Paladar , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo , Adulto JovemRESUMO
INTRODUCTION: The process of tomato (Solanum lycopersicum) breeding has affected negatively the fruit organoleptic properties and this is evident when comparing modern cultivars with heirloom varieties. Flavor of tomato fruit is determined by a complex combination of volatile and nonvolatile metabolites that is not yet understood. OBJECTIVES: The aim of this work was to provide an alternative approach to exploring the relationship between tomato odour/taste and volatile organic compounds (VOCs). METHODS: VOC composition and organoleptic properties of seven Andean tomato landraces along with an edible wild species (Solanum pimpinellifolium) and four commercial varieties were characterized. Six hedonic traits were analyzed by a semitrained sensory panel to describe the organoleptic properties. Ninety-four VOCs were analyzed by headspace solid phase microextraction/gas chromatography-mass spectrometry (HS/SPME/GC-MS). The relationship between sensory data and VOCs was explored using an Artificial Neural Networks model (Kohonen Self Organizing Maps, omeSOM). RESULTS AND CONCLUSION: The results showed a strong preference by panelists for tomatoes of landraces than for commercial varieties and wild species. The predictive analysis by omeSOM showed 15 VOCs significantly associated to the typical and atypical tomato odour and taste. Moreover, omeSOM was used to predict the relationship of VOC ratios with sensory data. A total of 108 VOC ratios out of 8837 VOC ratios were predicted to be contributing to the typical and atypical tomato odour and taste. The metabolic origin of these flavor-associated VOCs and the metabolic point or target for breeding strategies were discussed.
Assuntos
Solanum lycopersicum/química , Solanum lycopersicum/metabolismo , Compostos Orgânicos Voláteis/análise , Adulto , Colômbia , Feminino , Aromatizantes/análise , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Humanos , Solanum lycopersicum/fisiologia , Masculino , Pessoa de Meia-Idade , Redes Neurais de Computação , Odorantes , Melhoramento Vegetal , Análise de Componente Principal/métodos , Microextração em Fase Sólida/métodos , Paladar/fisiologia , Compostos Orgânicos Voláteis/metabolismoRESUMO
The aim of this study was to evaluate the toxic effects of chlorpyrifos (CPF) at environmental concentrations on the shrimp Palaemonetes argentinus, a South American native species. Organisms were exposed to environmentally relevant concentrations of CPF (from 3.5 to 94.5ngCPFL(-1)) at laboratory conditions for 96h. A wide battery of biochemical responses including bioaccumulation, damage and defense biomarkers were measured in cephalothorax and abdomen of shrimp. The concentration of CPF was below the detection limit of the method in both body sectors (8ngCPFg(-1)ww), probably indicating fast biotransformation of the parental compound. Our results showed that CPF exposure inhibits acetylcholinesterase activity from 3.5ngCPFL(-1), a concentration below the suggested Argentinean guidelines for the protection of aquatic biota. Moreover, oxidative stress was evidenced by increased H2O2 content and increased levels of TBARs and carbonyl groups in proteins. The induction of antioxidant enzymes like catalase, glutathione S-transferase and glutathione peroxidase seems not be sufficient to prevent oxidative damages. In addition, the mobilization of α-tocopherol from abdomen to cephalothorax was observed and reported for the first time in non-reproductive condition. Likewise, a strong diminution of metallothioneins occurred in cephalothorax from the lowest CPF concentration while induction occurred from the same treatment in abdomen as an oxidative stress response. Finally, significant correlation between Integrated Biomarker Response values and exposure concentrations suggest the usefulness of P. argentinus as bioindicator of CPF exposure at concentrations as low as environmental ones.
Assuntos
Biomarcadores/metabolismo , Clorpirifos/toxicidade , Inseticidas/toxicidade , Metalotioneína/metabolismo , Palaemonidae/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , alfa-Tocoferol/metabolismo , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Exposição Ambiental , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Palaemonidae/metabolismo , Poluentes Químicos da Água/químicaRESUMO
Data provide information about a tomato collection composed of accessions from the Andean Valley, commercial accessions and wild species. Antioxidant metabolites were measured in mature fruits of this collection, and their biological activities were assessed by both in vitro and in vivo methods. In this work, the parameters used to identify and quantify polyphenols compounds in tomato fruit by liquid chromatography coupled to diode array detector and quadrupole time of flight mass spectrometer are described. Moreover, data supporting a procedure to characterize the properties of tomato fruits to revert death by thermal stress in Caenorhabditis elegans are explained in detail. Lastly, principal component analysis and hierarchical cluster analysis of metabolites composition, antioxidant activities (in vivo and in vitro), tomato traits and geographical origin of the tomatoes collection are shown. The data presented here are related to the research article entitled "Hydrophilic antioxidants from Andean Tomato Landraces assessed by their bioactivities in vitro and in vivo" [1].