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1.
Sci Rep ; 14(1): 14685, 2024 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-38918476

RESUMO

Human milk oligosaccharides (HMOs) promote adequate intestinal microbiota development and favor the immune system's maturation and cognitive development. In addition to non-modifiable factors, HMOs composition can be influenced by other factors like body mass index and eating habits, but the reports are discrepant. The aim of this work was to describe the correlation between maternal factors and HMOs concentration in colostrum in 70 women from northeastern Mexico categorized into women with normal weight and women with overweight or obesity. The absolute concentration of six HMOs were significantly lower in women with overweight or obesity compared to women with normal weight (LNFPI p = 0.0021, 2'-FL p = 0.0304, LNT p = 0.0492, LNnT p = 0.00026, 3'-SL p = 0.0476, 6'-SL p = 0.00041). Another main finding was that the frequency of consumption of food groups such as vegetables, fruits and meats was positively correlated to specific HMOs (Poblano chili and 2'-FL; rs = 0.702, p = 0.0012; Orange or tangerine and 3-FL; rs = 0.428, p = 0.0022; Chicken and 2'-FL; rs = 0.615, p = 0.0039). This study contributes to the elucidation of how maternal factors influence the composition of HMOs and opens possibilities for future research aimed at mitigating overweight or obesity, consequently improving the quality of human milk.


Assuntos
Aleitamento Materno , Comportamento Alimentar , Leite Humano , Oligossacarídeos , Humanos , Leite Humano/química , Leite Humano/metabolismo , Feminino , México , Oligossacarídeos/análise , Adulto , Obesidade/metabolismo , Índice de Massa Corporal , Colostro/química , Colostro/metabolismo , Sobrepeso , Adulto Jovem
2.
Food Sci Nutr ; 12(6): 4063-4075, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38873484

RESUMO

Consumer acceptability of beers is influenced by product formulation and processing conditions, which impart unique sensory profiles. This study used multivariate techniques to evaluate at-home consumer sensory acceptability of six commercial beers considering their style, fermentation type, and chemical composition. Samples included top-fermented beers (American India Pale Ale and Stout) and bottom-fermented beers (Pilsner, zero-alcohol Pilsner, Vienna Lager, and Munich Dunkel). Beer consumers (n = 50) conducted sensory hedonic, check-all-that-apply (CATA) and just-about-right (JAR) tests. Chemometric variables included iso-alpha-acids, hordenine, and volatile aromatic compounds, quantified by chromatographic methods, whereas bitterness units (IBU) were determined spectrophotometrically. Lager beers had higher acceptability than top-fermented beer (p < .05) for all attributes. Light-colored beers and medium-height foams had the highest liking scores for visual sensory attributes. Higher concentrations of bitter-tasting molecules, hordenine, and acidity decreased the liking scores of top-fermented (Ale) beers, as a sensory penalty analysis suggested. In contrast, the most favored beers (Pilsners and Munich Dunkel) contained higher fusel alcohol esters linked to fruity aromatic notes. Although a low conversion rate of fatty acids into fruity esters was noted in nonalcoholic Pilsner, its overall liking score was not statistically different from the alcoholic version. However, consumers perceived the nonalcoholic Pilsner as less bitter than its alcoholic counterpart even when IBUs were nonsignificantly different. This study emphasized the significance of understanding beer chemometrics to comprehend consumer acceptability, highlighting the crucial role of bitter molecules. Hence, hordenine, acidity, and volatile contents provided additional and valuable insights into consumer preferences.

3.
Heliyon ; 9(11): e22475, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38028015

RESUMO

Oligosaccharides are significant in mammalian milk, where they serve as prebiotics that promote the growth of beneficial gut bacteria in infants. Comprehensive research of milk oligosaccharides requires precise and validated analytical methods for compositional studies. To address this need, the focus of our study was to develop and validate an analytical method using UPLC-MS/MS to quantify seven specific oligosaccharides found in mammalian milk. The developed and optimized method has adequate linearity, accuracy, and precision parameters. The detection (LOD) and quantification (LOQ) limits for the seven compounds ranged from 0.0018 to 0.0030 µg/mL and 0.0054-0.0063 µg/mL, respectively. The sample preparation method yielded recovery rates above 90.5 %. Furthermore, no significant matrix effect was observed. The validated method was successfully applied to human, goat, and bovine milk samples, demonstrating its proficiency in identifying variances in the concentration of oligosaccharides across different mammals. This versatile method will allow future research about factors affecting oligosaccharide composition.

4.
Plants (Basel) ; 12(7)2023 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-37050060

RESUMO

Wounding induces phenolic biosynthesis in broccoli. However, there is scarce information about the physiological and molecular mechanisms governing this stress response. In the present study, a chemical-genetics approach was used to elucidate the role of reactive oxygen species (ROS), jasmonic acid (JA), and ethylene (ET) as stress-signaling molecules in the wound-induced phenolic biosynthesis in broccoli. Wounding activated the biosynthesis of ET and JA. Likewise, the wound-induced biosynthesis of ET and JA was regulated by ROS. JA activated primary metabolism, whereas the three signaling molecules activated phenylpropanoid metabolism. The signaling molecules inhibited the wound-induced activation of the hydroxycinnamoyl-CoA quinate hydroxycinnamoyl transferase (HQT) gene, which is involved in caffeoylquinic acids biosynthesis, and the main phenolics accumulated in wounded broccoli, suggesting that an alternative caffeoylquinic biosynthesis pathway is activated in the tissue due to wounding. ROS mediated the biosynthesis of most individual phenolic compounds evaluated. In conclusion, ROS, ET, and JA are essential in activating broccoli's primary and secondary metabolism, resulting in phenolic accumulation.

5.
Plants (Basel) ; 10(12)2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34961133

RESUMO

Wounding stress is an effective strategy to induce glucosinolate (GS) biosynthesis in broccoli. However, there is insufficient knowledge on the physiological and molecular mechanisms underlying this stress response. Herein, a chemical-genetic approach was applied to elucidate the role of jasmonic acid (JA), ethylene (ET), and reactive oxygen species (ROS) on the wound-induced biosynthesis of GS. Broccoli was processed into chops to induce wounding stress. Broccoli chops were treated with phenidone (PHEN) and diphenyleneiodonium chloride (DPI) as inhibitors of JA and ROS biosynthesis, respectively, whereas 1-methylcyclopropene (1-MCP) was applied as an inhibitor of ET action. Wounding stress induced the expression of genes related to the biosynthesis of indolic and aliphatic GS, which was correlated with the accumulation of GS and modulated by the inhibitors of signaling molecules applied. Results of gene expression analysis indicated that JA played a key role in the activation of most genes, followed by ROS. Furthermore, except for the CYP79B2 gene, PHEN and 1-MCP synergistically downregulated the expression of GS biosynthetic genes evaluated, showing that the interaction between JA and ET was fundamental to modulate GS biosynthesis. Results presented herein increased our knowledge of the physiological and molecular mechanisms governing the wound-induced biosynthesis of GS in broccoli.

6.
Foods ; 10(2)2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33494486

RESUMO

In this study, the effects of static and multi-pulsed mild-intensity high hydrostatic pressure (HHP) treatments (60 or 100 MPa, ~23 °C) on the extractability and accumulation of phenolics and carotenoids in whole carrots were evaluated. HHP treatments were applied for the time needed to reach the desired pressure (come-up-time, CUT) either as a single pulse or multi-pulse (2P, 3P, and 4P). Likewise, a single sustained treatment (5 min) applied at 60 or 100 MPa was evaluated. Individual carotenoids, free and bound phenolics were quantified after HHP treatment and subsequent storage (48 h, 15 °C). As an immediate HHP response, phenolic extractability increased by 66.65% and 80.77% in carrots treated with 3P 100 MPa and 4P 60 MPa, respectively. After storage, CUT 60 MPa treatment accumulated free (163.05%) and bound (36.95%) phenolics. Regarding carotenoids, total xanthophylls increased by 27.16% after CUT 60 MPa treatment, whereas no changes were observed after storage. Results indicate that HHP processing of whole carrots at mild conditions is a feasible innovative tool to enhance the nutraceutical properties of whole carrots by increasing their free and bound phenolic content while maintaining carotenoid levels. HHP treated carrots can be used as a new functional food or as raw material for the production of food and beverages with enhanced levels of nutraceuticals.

7.
Foods ; 9(6)2020 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-32580405

RESUMO

Some chemical compounds, especially alcohol, sugars, and alkaloids such as hordenine, have been reported as elicitors of different emotional responses. This preliminary study was based on six commercial beers selected according to their fermentation type, with two beers of each type (spontaneous, bottom, and top). Chemometry and sensory analysis were performed for all samples to determine relationships and patterns between chemical composition and emotional responses from consumers. The results showed that sweeter samples were associated with higher perceived liking by consumers and positive emotions, which corresponded to spontaneous fermentation beers. There was high correlation (R = 0.91; R2 = 0.83) between hordenine and alcohol content. Beers presenting higher concentrations of both, and higher bitterness, were related to negative emotions. Further studies should be conducted, giving more time for emotional response analysis between beer samples, and comparing alcoholic and non-alcoholic beers with similar styles, to separate the effects of alcohol and hordenine. This preliminary study was a first attempt to associate beer compounds with the emotional responses of consumers using non-invasive biometrics.

8.
Metabolites ; 10(2)2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32059429

RESUMO

Formaldehyde is a highly reactive compound that participates in multiple spontaneous reactions, but these are mostly deleterious and damage cellular components. In contrast, the spontaneous condensation of formaldehyde with tetrahydrofolate (THF) has been proposed to contribute to the assimilation of this intermediate during growth on C1 carbon sources such as methanol. However, the in vivo rate of this condensation reaction is unknown and its possible contribution to growth remains elusive. Here, we used microbial platforms to assess the rate of this condensation in the cellular environment. We constructed Escherichia coli strains lacking the enzymes that naturally produce 5,10-methylene-THF. These strains were able to grow on minimal medium only when equipped with a sarcosine (N-methyl-glycine) oxidation pathway that sustained a high cellular concentration of formaldehyde, which spontaneously reacts with THF to produce 5,10-methylene-THF. We used flux balance analysis to derive the rate of the spontaneous condensation from the observed growth rate. According to this, we calculated that a microorganism obtaining its entire biomass via the spontaneous condensation of formaldehyde with THF would have a doubling time of more than three weeks. Hence, this spontaneous reaction is unlikely to serve as an effective route for formaldehyde assimilation.

9.
Molecules ; 24(13)2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31247930

RESUMO

Acetogenins are bioactive fatty acid derivatives found in avocado tissues. Their efficacy as antimicrobials has been documented and initiated interest to use them as replacements of synthetic food additives. The present work focused on evaluation of multiple analytical methodologies for detection and quantification of organic solids present in a food-grade acetogenin-enriched extract (Avosafe®), and on its safety evaluations using bacterial reverse mutation (AMES) tests and acute oral toxicity to rat assays. Results confirmed chemical structures of two acetogenins as present in Avosafe® (AcO-avocadyne-(0) and AcO-avocadiene B-(3)), and together with seven other previously known compounds, quantified 94.74 ± 5.77% w/w of its solids as acetogenins. Safety evaluations indicated that Avosafe® was non-mutagenic and had an acute median lethal oral dose (LD50) to rats higher than the maximum concentration tested (>2000 mg·kg-1), with no signs of macroscopic abnormalities in organs. Mean body weight and hematological and biochemical parameters were normal after 14 days of a single oral dose of 2000 mg·kg-1. The results advance scientific information on the safety of avocado seed acetogenins and also generate new knowledge on profiles and concentrations of individual acetogenins found in avocado tissues (seed, pulp, and leaves) and in Avosafe®.


Assuntos
Acetogeninas/química , Acetogeninas/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Persea/química , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Sementes/química , Cromatografia Líquida de Alta Pressão , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
10.
Food Chem ; 277: 362-372, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30502158

RESUMO

High hydrostatic pressure (HHP) processing is a non-thermal technology reported to increase desirable metabolites in plant foods. This work evaluated changes in carotenoid accumulation in fresh-cut papaya fruit as affected by HHP treatment (50-400 MPa for 3-60 min) and during subsequent storage at 4 °C; simultaneously, transcriptional activities of carotenoid biosynthetic genes and oxidative stress markers were evaluated. LC-MS analyses revealed that HHP treatment increased carotenoid precursors and carotenes contents following processing and storage: lycopene levels increased up to 11-fold compared to the non-treated samples, and H2O2 and lipid peroxidation were concomitantly increased. qRT-PCR of intact RNA showed that the amount of phytoene desaturase transcripts increased after HHP treatment, and that they were correlated with carotene accumulation. This is the first study to show that HHP treatment triggers de novo carotenoid biosynthesis, which is regulated at the transcriptional level, possibly by inducing oxidative stress signaling in fruit tissue.


Assuntos
Carica/metabolismo , Carotenoides/biossíntese , Frutas/metabolismo , Carica/genética , Cromatografia Líquida , Temperatura Baixa , Manipulação de Alimentos , Frutas/genética , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Pressão Hidrostática , Peroxidação de Lipídeos/efeitos dos fármacos , Licopeno/análise , Análise Multivariada , Estresse Oxidativo/efeitos dos fármacos , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ativação Transcricional/genética
11.
Nat Commun ; 7: 11640, 2016 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-27291711

RESUMO

DNA methylation is an epigenetic mechanism that has important functions in transcriptional silencing and is associated with repressive histone methylation (H3K9me). To further investigate silencing mechanisms, we screened a mutagenized Arabidopsis thaliana population for expression of SDCpro-GFP, redundantly controlled by DNA methyltransferases DRM2 and CMT3. Here, we identify the hypomorphic mutant mthfd1-1, carrying a mutation (R175Q) in the cytoplasmic bifunctional methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase (MTHFD1). Decreased levels of oxidized tetrahydrofolates in mthfd1-1 and lethality of loss-of-function demonstrate the essential enzymatic role of MTHFD1 in Arabidopsis. Accumulation of homocysteine and S-adenosylhomocysteine, genome-wide DNA hypomethylation, loss of H3K9me and transposon derepression indicate that S-adenosylmethionine-dependent transmethylation is inhibited in mthfd1-1. Comparative analysis of DNA methylation revealed that the CMT3 and CMT2 pathways involving positive feedback with H3K9me are mostly affected. Our work highlights the sensitivity of epigenetic networks to one-carbon metabolism due to their common S-adenosylmethionine-dependent transmethylation and has implications for human MTHFD1-associated diseases.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Metilação de DNA/genética , Meteniltetra-Hidrofolato Cicloidrolase/metabolismo , Metilenotetra-Hidrofolato Desidrogenase (NADP)/metabolismo , Proteínas de Arabidopsis/genética , Citoplasma/efeitos dos fármacos , Citoplasma/metabolismo , Desmetilação do DNA , Epigênese Genética , Ácido Fólico/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Inativação Gênica , Proteínas de Fluorescência Verde/metabolismo , Histonas/metabolismo , Homeostase/efeitos dos fármacos , Lisina/metabolismo , Meteniltetra-Hidrofolato Cicloidrolase/genética , Metionina/farmacologia , Metilenotetra-Hidrofolato Desidrogenase (NADP)/genética , Modelos Biológicos , Mutação/genética , Transporte Proteico/efeitos dos fármacos , S-Adenosilmetionina/metabolismo , Tetra-Hidrofolatos/farmacologia
12.
Food Funct ; 6(4): 1352-60, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25797308

RESUMO

Dietary guidelines recommend the daily consumption of fruits; however, healthy and type 2 diabetes mellitus (T2DM) subjects receive conflicting messages regarding ingestion of fruits, such as mango, because of its sugar content. We investigated the effects of high hydrostatic pressure (HHP) processing of fresh mango puree (MP) on the glycemic indexes (GIs) and postprandial glycemic responses of 38 healthy Mexican subjects in a randomized cross-over clinical trial. Physicochemical characterization of MP included sugar profiles by HPLC-ELSD, starch, fibers, moisture, viscosity, swelling capacity and solubility properties of alcohol insoluble residue (AIR). The mean GI for HHP-MP was significantly lower (32.7 ± 13.4) than that of unprocessed-MP (42.7 ± 19.5). A significantly higher proportion of subjects showed a low GI following the consumption of HHP-MP compared to unprocessed-MP and none of them showed a high GI for the HHP-MP, compared to a significantly higher proportion for the unprocessed-MP. The viscosity and AIR solubility values of HHP-MP samples were significantly higher, which influenced glucose peaking later (Tmax) at 45 minutes and induced 20% lower AUC values than unprocessed-MP, corresponding to greater retardation indexes. The study findings support data stating that low GI fruits are appropriate for glycemic control and that mango may be included as part of healthy subjects' diets and potentially T2DM subjects' diets. Furthermore, HHP processing of mango may offer additional benefits for glycemic control, as its performance regarding GI, AUC and Tmax was significantly better than that of the unprocessed-MP. To our knowledge, this is the first report on the impact of this commercial non-thermal pasteurization technology on glucose metabolism.


Assuntos
Manipulação de Alimentos/métodos , Índice Glicêmico , Pressão Hidrostática , Mangifera/química , Adulto , Glicemia/metabolismo , Fenômenos Químicos , Estudos Cross-Over , Diabetes Mellitus Tipo 2/sangue , Carboidratos da Dieta/administração & dosagem , Carboidratos da Dieta/análise , Fibras na Dieta/administração & dosagem , Fibras na Dieta/análise , Jejum , Feminino , Frutas/química , Voluntários Saudáveis , Humanos , Insulina/sangue , Masculino , México , Pessoa de Meia-Idade , Período Pós-Prandial , Adulto Jovem
13.
New Phytol ; 202(4): 1223-1236, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24635769

RESUMO

Roots have both indeterminate and determinate developmental programs. The latter is preceded by the former. It is not well understood how the indeterminacy-to-determinacy switch (IDS) is regulated. We isolated a moots koom2 (mko2; 'short root' in Mayan) Arabidopsis thaliana mutant with determinate primary root growth and analyzed the root apical meristem (RAM) behavior using various marker lines. Deep sequencing and genetic and pharmacological complementation permitted the identification of a point mutation in the FOLYLPOLYGLUTAMATE SYNTHETASE1 (FPGS1) gene responsible for the mko2 phenotype. Wild-type FPGS1 is required to maintain the IDS in the 'off' state. When FPGS1 function is compromised, the IDS is turned on and the RAM becomes completely consumed. The polyglutamate-dependent pathway of the IDS involves activation of the quiescent center independently of auxin gradients and regulatory modules participating in RAM maintenance (WUSCHEL-RELATED HOMEOBOX5 (WOX5), PLETHORA, and SCARECROW (SCR)). The mko2 mutation causes drastic changes in folate metabolism and also affects lateral root primordium morphogenesis but not initiation. We identified a metabolism-dependent pathway involved in the IDS in roots. We suggest that the root IDS represents a specific developmental pathway that regulates RAM behaviour and is a different level of regulation in addition to RAM maintenance.


Assuntos
Arabidopsis/genética , Ácido Fólico/metabolismo , Peptídeo Sintases/genética , Arabidopsis/citologia , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Meristema/citologia , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/metabolismo , Peptídeo Sintases/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Mutação Puntual , Transdução de Sinais , Nicho de Células-Tronco
14.
Plant Foods Hum Nutr ; 69(1): 57-64, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24445671

RESUMO

Folate deficiency is a global health problem related to neural tube defects, cardiovascular disease, dementia, and cancer. Considering that folic acid (FA) supply through industrialized foods is the most successful intervention, limitations exist for its complete implementation worldwide. Biofortification of plant foods, on the other hand, could be implemented in poor areas as a complementary alternative. A biofortified tomato fruit that accumulates high levels of folates was previously developed. In this study, we evaluated short-term folate bioavailability in rats infused with this folate-biofortified fruit. Fruit from tomato segregants hyperaccumulated folates during an extended ripening period, ultimately containing 3.7-fold the recommended dietary allowance in a 100-g portion. Folate-depleted Wistar rats separated in three groups received a single dose of 1 nmol of folate/g body weight in the form of lyophilized biofortified tomato fruit, FA, or synthetic 5-CH3-THF. Folate bioavailability from the biofortified tomato was comparable to that of synthetic 5-CH3-THF, with areas under the curve (AUC(0-∞)) of 2,080 ± 420 and 2,700 ± 220 pmol · h/mL, respectively (P = 0.12). Whereas, FA was less bioavailable with an AUC(0-∞) of 750 ± 10 pmol · h/mL. Fruit-supplemented animals reached maximum levels of circulating folate in plasma at 2 h after administration with a subsequent steady decline, while animals treated with FA and synthetic 5-CH3-THF reached maximum levels at 1 h. Pharmacokinetic parameters revealed that biofortified tomato had slower intestinal absorption than synthetic folate forms. This is the first study that demonstrates the bioavailability of folates from a biofortified plant food, showing its potential to improve folate deficiency.


Assuntos
Deficiência de Ácido Fólico/dietoterapia , Ácido Fólico/farmacocinética , Alimentos Fortificados , Frutas/química , Solanum lycopersicum/química , Tetra-Hidrofolatos/farmacocinética , Complexo Vitamínico B/farmacocinética , Animais , Área Sob a Curva , Disponibilidade Biológica , Suplementos Nutricionais , Ácido Fólico/uso terapêutico , Humanos , Absorção Intestinal , Masculino , Ratos , Ratos Wistar , Tetra-Hidrofolatos/uso terapêutico , Complexo Vitamínico B/uso terapêutico
15.
J Agric Food Chem ; 61(16): 3949-56, 2013 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-23574547

RESUMO

Folates are essential micronutrients for humans, and their deficiency causes several detrimental effects on human health. Papaya fruit is an important natural source of some micronutrients. This paper presents a first complete characterization of folate derivatives accumulated in cv. Maradol papaya during fruit development and ripening processes. During postharvest ripening, the fruit accumulated up to 24.5% of the daily folate recommended dietary allowance (RDA) for an adult in a 1 cup (145 g) portion. Tetrahydrofolate (THF) and 5-methyl-THF were the predominant folate classes observed. Surprisingly, an unusually long polyglutamylation profile of tentatively up to 17 glutamates linked to 5-methyl-THF was detected; to the authors' knowledge, this very long polyglutamyl tail has not been reported for any organism, and it is probably characteristic of this plant species. This polyglutamylation degree changed throughout fruit development and ripening, showing the largest differences at the onset of ripening. This work raises questions about the functional role of folate derivatives in fruit development.


Assuntos
Carica/química , Ácido Fólico/análise , Ácido Fólico/química , Frutas/química , Frutas/crescimento & desenvolvimento , Fenômenos Químicos , Ácido Fólico/metabolismo , Frutas/metabolismo , Recomendações Nutricionais , Tetra-Hidrofolatos/análise
16.
Plant Physiol ; 155(3): 1237-51, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21233333

RESUMO

A recessive Arabidopsis (Arabidopsis thaliana) mutant with short primary roots and root hairs was identified from a forward genetic screen. The disrupted gene in the mutant encoded the plastidial isoform of folylpolyglutamate synthetase (FPGS), previously designated as AtDFB, an enzyme that catalyzes the addition of glutamate residues to the folate molecule to form folylpolyglutamates. The short primary root of atdfb was associated with a disorganized quiescent center, dissipated auxin gradient in the root cap, bundled actin cytoskeleton, and reduced cell division and expansion. The accumulation of monoglutamylated forms of some folate classes in atdfb was consistent with impaired FPGS function. The observed cellular defects in roots of atdfb underscore the essential role of folylpolyglutamates in the highly compartmentalized one-carbon transfer reactions (C1 metabolism) that lead to the biosynthesis of compounds required for metabolically active cells found in the growing root apex. Indeed, metabolic profiling uncovered a depletion of several amino acids and nucleotides in atdfb indicative of broad alterations in metabolism. Methionine and purines, which are synthesized de novo in plastids via C1 enzymatic reactions, were particularly depleted. The root growth and quiescent center defects of atdfb were rescued by exogenous application of 5-formyl-tetrahydrofolate, a stable folate that was readily converted to metabolically active folates. Collectively, our results indicate that AtDFB is the predominant FPGS isoform that generates polyglutamylated folate cofactors to support C1 metabolism required for meristem maintenance and cell expansion during postembryonic root development in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Peptídeo Sintases/metabolismo , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , Plastídeos/enzimologia , Arabidopsis/citologia , Arabidopsis/genética , Carbono/metabolismo , Divisão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Genoma de Planta/genética , Ácido Glutâmico/metabolismo , Guanosina/farmacologia , Ácidos Indolacéticos/metabolismo , Isoenzimas/metabolismo , Metaboloma/efeitos dos fármacos , Metionina/farmacologia , Mutação/genética , Fenótipo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Tetra-Hidrofolatos/metabolismo
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