Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
Plant Physiol Biochem ; 214: 108889, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38954945

RESUMO

Abscisic acid (ABA) is crucial for plant water deficit (WD) acclimation, but how the interplay between ABA and guard cell (GC) metabolism aids plant WD acclimation remains unclear. Here, we investigated how ABA regulates GC metabolism and how this contributes to plant WD acclimation using tomato wild type (WT) and the ABA-deficient sitiens mutant. These genotypes were characterized at physiological, metabolic, and transcriptional levels under recurring WD periods and were used to perform a13C-glucose labelling experiment using isolated guard cells following exogenously applied ABA. ABA deficiency altered the level of sugars and organic acids in GCs in both irrigated and WD plants and the dynamic of accumulation/degradation of these compounds in GCs during the dark-to-light transition. WD-induced metabolic changes were more pronounced in sitiens than WT GCs. Results from the 13C-labelling experiment indicate that ABA is required for the glycolytic fluxes toward malate and acts as a negative regulator of a putative sucrose substrate cycle. The expression of key ABA-biosynthetic genes was higher in WT than in sitiens GCs after two cycles of WD. Additionally, the intrinsic leaf water use efficiency increased only in WT after the second WD cycle, compared to sitiens. Our results highlight that ABA deficiency disrupts the homeostasis of GC primary metabolism and the WD memory, negatively affecting plant WD acclimation. Our study demonstrates which metabolic pathways are activated by WD and/or regulated by ABA in GCs, which improves our understanding of plant WD acclimation, with clear consequences for plant metabolic engineering in the future.


Assuntos
Ácido Abscísico , Solanum lycopersicum , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Solanum lycopersicum/metabolismo , Solanum lycopersicum/genética , Estômatos de Plantas/metabolismo , Estômatos de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos
2.
Plants (Basel) ; 13(14)2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-39065432

RESUMO

The Brazilian Atlantic Forest, renowned for its exceptional species richness and high endemism, acts as a vital reservoir of terrestrial biodiversity, often referred to as a biodiversity hotspot. Consequently, there is an urgent need to restore this forest to safeguard certain species and to unravel the ecophysiological adaptations of others. This study aims to integrate some physiological parameters, including gas exchange and chlorophyll a fluorescence, with anatomical and metabolic techniques to elucidate how five different native species (Paubrasilia echinata, Chorisia glaziovii, Clusia nemorosa, Licania tomentosa, and Schinus terebinthifolius), each occupying distinct ecological niches, respond to seasonal variations in rainfall and their consequences. Our investigation has revealed that C. nemorosa and P. echinata exhibit robust mechanisms to mitigate the adverse effects of drought. In contrast, others demonstrate greater adaptability (e.g., S. terebinthifolia and C. glaziovii). In this context, exploring metabolic pathways has proven invaluable in comprehending the physiological strategies and their significance in species acclimatization. This study provides a comprehensive overview of the impact of water restrictions and their consequential effects on various species, defining the strategies each species uses to mitigate water privation during the dry season.

3.
Rev. argent. cir ; 115(3): 270-273, ago. 2023. graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1514933

RESUMO

RESUMEN El tratamiento no operatorio (TNO) de lesiones abdominales en traumatismo cerrado de abdomen (TCA) se basa en pilares clínicos y radiológicos. Presentamos el de caso de paciente masculino de 16 años que ingresa en el Servicio de Emergencias por dolor abdominal en hipocondrio izquierdo y antecedente de traumatismo cerrado de abdomen reciente. Se establece protocolo de TNO basado en cuadro clínico e imágenes pero, en forma posterior, ante la evolución desfavorable, se cambia la conducta y se realiza tratamiento laparoscópico conservador de órgano.


ABSTRACT Nonoperative management (NOM) of organ injuries in abdominal blunt trauma (ABT) is based on clinical and imaging test findings. We herein present a 16-year-old male patient with a history of recent blunt abdominal trauma was admitted to the emergency department for abdominal pain in the left hypochondrium. A protocol for NOM was established based on the clinical picture and imaging findings, but afterwards, in view of the unfavorable progression, the approach was modified to laparoscopic organ-preserving surgery.

4.
Plant Physiol Biochem ; 201: 107862, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37413941

RESUMO

Evidence suggests that guard cells have higher rate of phosphoenolpyruvate carboxylase (PEPc)-mediated dark CO2 assimilation than mesophyll cells. However, it is unknown which metabolic pathways are activated following dark CO2 assimilation in guard cells. Furthermore, it remains unclear how the metabolic fluxes throughout the tricarboxylic acid (TCA) cycle and associated pathways are regulated in illuminated guard cells. Here we carried out a13C-HCO3 labelling experiment in tobacco guard cells harvested under continuous dark or during the dark-to-light transition to elucidate principles of metabolic dynamics downstream of CO2 assimilation. Most metabolic changes were similar between dark-exposed and illuminated guard cells. However, illumination altered the metabolic network structure of guard cells and increased the 13C-enrichment in sugars and metabolites associated to the TCA cycle. Sucrose was labelled in the dark, but light exposure increased the 13C-labelling and leads to more drastic reductions in the content of this metabolite. Fumarate was strongly labelled under both dark and light conditions, while illumination increased the 13C-enrichment in pyruvate, succinate and glutamate. Only one 13C was incorporated into malate and citrate in either dark or light conditions. Our results indicate that several metabolic pathways are redirected following PEPc-mediated CO2 assimilation in the dark, including gluconeogenesis and the TCA cycle. We further showed that the PEPc-mediated CO2 assimilation provides carbons for gluconeogenesis, the TCA cycle and glutamate synthesis and that previously stored malate and citrate are used to underpin the specific metabolic requirements of illuminated guard cells.


Assuntos
Dióxido de Carbono , Malatos , Malatos/metabolismo , Dióxido de Carbono/metabolismo , Células do Mesofilo/metabolismo , Fosfoenolpiruvato Carboxilase/metabolismo , Citratos/metabolismo
5.
Metabolites ; 13(4)2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37110197

RESUMO

Plants are sessile, and their ability to reprogram their metabolism to adapt to fluctuations in soil water level is crucial but not clearly understood. A study was performed to determine alterations in intermediate metabolites involved in central carbon metabolism (CCM) following exposure of Mexican mint (Plectranthus amboinicus) to varying watering regimes. The water treatments were regular watering (RW), drought (DR), flooding (FL), and resumption of regular watering after flooding (DHFL) or after drought (RH). Leaf cluster formation and leaf greening were swift following the resumption of regular watering. A total of 68 key metabolites from the CCM routes were found to be significantly (p < 0.01) impacted by water stress. Calvin cycle metabolites in FL plants, glycolytic metabolites in DR plants, total tricarboxylic acid (TCA) cycle metabolites in DR and DHFL plants, and nucleotide biosynthetic molecules in FL and RH plants were significantly (p < 0.05) increased. Pentose phosphate pathway (PPP) metabolites were equally high in all the plants except DR plants. Total Calvin cycle metabolites had a significantly (p < 0.001) strong positive association with TCA cycle (r = 0.81) and PPP (r = 0.75) metabolites. Total PPP metabolites had a moderately positive association with total TCA cycle metabolites (r = 0.68; p < 0.01) and a negative correlation with total glycolytic metabolites (r = -0.70; p < 0.005). In conclusion, the metabolic alterations of Mexican mint plants under different watering regimes were revealed. Future studies will use transcriptomic and proteomic approaches to identify genes and proteins that regulate the CCM route.

6.
Free Radic Biol Med ; 197: 71-84, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36738801

RESUMO

Mitochondrial aconitase (ACO2) has been postulated as a redox sensor in the tricarboxylic acid cycle. Its high sensitivity towards reactive oxygen and nitrogen species is due to its particularly labile [4Fe-4S]2+ prosthetic group which yields an inactive [3Fe-4S]+ cluster upon oxidation. Moreover, ACO2 was found as a main oxidant target during aging and in pathologies where mitochondrial dysfunction is implied. Herein, we report the expression and characterization of recombinant human ACO2 and its interaction with frataxin (FXN), a protein that participates in the de novo biosynthesis of Fe-S clusters. A high yield of pure ACO2 (≥99%, 22 ± 2 U/mg) was obtained and kinetic parameters for citrate, isocitrate, and cis-aconitate were determined. Superoxide, carbonate radical, peroxynitrite, and hydrogen peroxide reacted with ACO2 with second-order rate constants of 108, 108, 105, and 102 M-1 s-1, respectively. Temperature-induced unfolding assessed by tryptophan fluorescence of ACO2 resulted in apparent melting temperatures of 51.1 ± 0.5 and 43.6 ± 0.2 °C for [4Fe-4S]2+ and [3Fe-4S]+ states of ACO2, sustaining lower thermal stability upon cluster oxidation. Differences in protein dynamics produced by the Fe-S cluster redox state were addressed by molecular dynamics simulations. Reactivation of [3Fe-4S]+-ACO2 by FXN was verified by activation assays and direct iron-dependent interaction was confirmed by protein-protein interaction ELISA and fluorescence spectroscopic assays. Multimer modeling and protein-protein docking predicted an ACO2-FXN complex where the metal ion binding region of FXN approaches the [3Fe-4S]+ cluster, supporting that FXN is a partner for reactivation of ACO2 upon oxidative cluster inactivation.


Assuntos
Proteínas de Ligação ao Ferro , Proteínas Ferro-Enxofre , Humanos , Proteínas de Ligação ao Ferro/genética , Proteínas de Ligação ao Ferro/metabolismo , Oxirredução , Superóxidos/metabolismo , Aconitato Hidratase/metabolismo , Proteínas Ferro-Enxofre/genética , Proteínas Ferro-Enxofre/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Frataxina
7.
Food Chem ; 411: 135498, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-36696718

RESUMO

Consumers around the world prefer high quality table grapes. To achieve higher quality traits at ripening, grapevine producers apply different plant growth regulators. The synthetic cytokinin forchlorfenuron N-(2-chloro-4-pyridinyl)-N'-phenylurea (CPPU) is widely used, its effect on grape quality is poorly understood. We hypothesized that the use of CPPU in pre-flowering can lead to changes in the metabolism that affects grape quality at harvest. Therefore, we investigated the role of CPPU applications on the quality of grapes by integrating proteomics and metabolomics. CPPU-treated grapevines showed a significant increase in berry size and firmness. Proteomic analyses indicated that CPPU-treated berries accumulated enzymes associated with carbohydrate metabolism, glycolysis, and tricarboxylic acid (TCA) cycle at harvest. Metabolomic analyses showed shifts in the abundance of compounds associated with carbohydrate metabolism and TCA cycle in CPPU-treated grapes. These findings suggest that CPPU applications modulate central carbon metabolism, improving grape berry quality.


Assuntos
Citocininas , Vitis , Vitis/metabolismo , Frutas/metabolismo , Proteômica , Metabolômica
8.
Cancer Treat Res Commun ; 32: 100600, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35811248

RESUMO

Evidence supports the antitumoral effects of physical activity, either in experimental animal models or humans. However, the biological mechanisms by which physical exercise modulates tumoral development are still unclear. An important feature of the tumor cells is the altered energy metabolism, often associated with definitions of tumor aggressiveness. Nevertheless, exercise can cause global metabolic changes in the body, as well as modulate tumor metabolism. Here we specifically discuss the metabolic changes found in tumors and how exercise can contribute to anti-tumoral effects by modulating the mitochondrial function, and tricarboxylic acid cycle-related metabolites of cancer cells. The effect of physical exercise on tumor metabolism is a new possibility for comprehension of cancer biology and developing therapies focused on tumor energy metabolism.


Assuntos
Metabolismo Energético , Neoplasias , Animais , Ciclo do Ácido Cítrico , Exercício Físico , Humanos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Neoplasias/patologia , Neoplasias/terapia
9.
Toxins (Basel) ; 14(4)2022 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-35448860

RESUMO

The neurotoxic alkaloid ß-N-methyl-amino-l-alanine (BMAA) and related isomers, including N-(2-aminoethyl glycine) (AEG), ß-amino-N-methyl alanine (BAMA), and 2,4-diaminobutyric acid (DAB), have been reported previously in cyanobacterial samples. However, there are conflicting reports regarding their occurrence in surface waters. In this study, we evaluated the impact of amending lake water samples with trichloroacetic acid (0.1 M TCA) on the detection of BMAA isomers, compared with pre-existing protocols. A sensitive instrumental method was enlisted for the survey, with limits of detection in the range of 5−10 ng L−1. Higher detection rates and significantly greater levels (paired Wilcoxon's signed-rank tests, p < 0.001) of BMAA isomers were observed in TCA-amended samples (method B) compared to samples without TCA (method A). The overall range of B/A ratios was 0.67−8.25 for AEG (up to +725%) and 0.69−15.5 for DAB (up to +1450%), with absolute concentration increases in TCA-amended samples of up to +15,000 ng L−1 for AEG and +650 ng L−1 for DAB. We also documented the trends in the occurrence of BMAA isomers for a large breadth of field-collected lakes from Brazil, Canada, France, Mexico, and the United Kingdom. Data gathered during this overarching campaign (overall, n = 390 within 45 lake sampling sites) indicated frequent detections of AEG and DAB isomers, with detection rates of 30% and 43% and maximum levels of 19,000 ng L−1 and 1100 ng L−1, respectively. In contrast, BAMA was found in less than 8% of the water samples, and BMAA was not found in any sample. These results support the analyses of free-living cyanobacteria, wherein BMAA was often reported at concentrations of 2−4 orders of magnitude lower than AEG and DAB. Seasonal measurements conducted at two bloom-impacted lakes indicated limited correlations of BMAA isomers with total microcystins or chlorophyll-a, which deserves further investigation.


Assuntos
Diamino Aminoácidos , Cianobactérias , Alanina , Diamino Aminoácidos/análise , Brasil , Lagos/microbiologia , México , Neurotoxinas/análise , Água/análise
10.
Front Cell Dev Biol ; 9: 751301, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34733852

RESUMO

The role of metabolism in tumor growth and chemoresistance has received considerable attention, however, the contribution of mitochondrial bioenergetics in migration, invasion, and metastasis is recently being understood. Migrating cancer cells adapt their energy needs to fluctuating changes in the microenvironment, exhibiting high metabolic plasticity. This occurs due to dynamic changes in the contributions of metabolic pathways to promote localized ATP production in lamellipodia and control signaling mediated by mitochondrial reactive oxygen species. Recent evidence has shown that metabolic shifts toward a mitochondrial metabolism based on the reductive carboxylation, glutaminolysis, and phosphocreatine-creatine kinase pathways promote resistance to anoikis, migration, and invasion in cancer cells. The PGC1a-driven metabolic adaptations with increased electron transport chain activity and superoxide levels are essential for metastasis in several cancer models. Notably, these metabolic changes can be determined by the composition and density of the extracellular matrix (ECM). ECM stiffness, integrins, and small Rho GTPases promote mitochondrial fragmentation, mitochondrial localization in focal adhesion complexes, and metabolic plasticity, supporting enhanced migration and metastasis. Here, we discuss the role of ECM in regulating mitochondrial metabolism during migration and metastasis, highlighting the therapeutic potential of compounds affecting mitochondrial function and selectively block cancer cell migration.

11.
Antioxidants (Basel) ; 10(10)2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34679752

RESUMO

Since breast cancer (BC) cells are dependent on mitochondrial bioenergetics for promoting proliferation, survival, and metastasis, mitochondria highlight as an important target for anticancer drug discovery. FRI-1, methyl 1, 3-dimethyl-5, 8-dioxo-5, 8-dihydro-4-isoquinolinecarboxylate, was previously described as a selective cytotoxic compound on cancer cell lines, however, details on the mechanism of action remain unknown. In this work, we describe that FRI-1 inhibits mitochondrial bioenergetics, producing apoptosis in MCF7 and MDA-MB-231 BC cell lines. FRI-1 decreases the maximal oxygen consumption rate (OCR), Δψm, NADH, and ATP levels, with a notable increase of mitochondrial reactive oxygen species (ROS) production, promoting AMPK activation with pro-survival effects. Moreover, FRI-1 inhibits the metabolic remodeling to glycolysis induced by oligomycin. In isolated tumoral mitochondria, FRI-1 increases Complex I and III-dependent OCR state 2, and this is sensitive to rotenone and antimycin A inhibitor additions, suggesting a redox cycling event. Remarkably, α-ketoglutarate and lipoic acid supplementation reversed and promoted, respectively, the FRI-1-induced apoptosis, suggesting that mitochondrial redox disruption affects 2-oxoglutarate dehydrogenase (OGDH) activity, and this is involved in their anticancer mechanism. Consistent with this, the combination of FRI-1 and CPI-613, a dual inhibitor of redox-sensible tricarboxylic acid (TCA) cycle enzymes PDH and OGDH, produced extensive BC cell death. Taken together, our results suggest that FRI-1 exhibits anticancer effects through inhibition of mitochondrial bioenergetics by redox disruption in BC cells.

12.
Biomolecules ; 11(9)2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34572472

RESUMO

Mitochondria are complex organelles that orchestrate several functions in the cell. The primary function recognized is energy production; however, other functions involve the communication with the rest of the cell through reactive oxygen species (ROS), calcium influx, mitochondrial DNA (mtDNA), adenosine triphosphate (ATP) levels, cytochrome c release, and also through tricarboxylic acid (TCA) metabolites. Kidney function highly depends on mitochondria; hence mitochondrial dysfunction is associated with kidney diseases. In addition to oxidative phosphorylation impairment, other mitochondrial abnormalities have been described in kidney diseases, such as induction of mitophagy, intrinsic pathway of apoptosis, and releasing molecules to communicate to the rest of the cell. The TCA cycle is a metabolic pathway whose primary function is to generate electrons to feed the electron transport system (ETS) to drives energy production. However, TCA cycle metabolites can also release from mitochondria or produced in the cytosol to exert different functions and modify cell behavior. Here we review the involvement of some of the functions of TCA metabolites in kidney diseases.


Assuntos
Ciclo do Ácido Cítrico , Nefropatias/metabolismo , Metaboloma , Animais , Biomarcadores/metabolismo , Humanos , Modelos Biológicos
13.
Biomolecules ; 11(8)2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34439810

RESUMO

Mitochondria are essential organelles in physiology and kidney diseases, because they produce cellular energy required to perform their function. During mitochondrial metabolism, reactive oxygen species (ROS) are produced. ROS function as secondary messengers, inducing redox-sensitive post-translational modifications (PTM) in proteins and activating or deactivating different cell signaling pathways. However, in kidney diseases, ROS overproduction causes oxidative stress (OS), inducing mitochondrial dysfunction and altering its metabolism and dynamics. The latter processes are closely related to changes in the cell redox-sensitive signaling pathways, causing inflammation and apoptosis cell death. Although mitochondrial metabolism, ROS production, and OS have been studied in kidney diseases, the role of redox signaling pathways in mitochondria has not been addressed. This review focuses on altering the metabolism and dynamics of mitochondria through the dysregulation of redox-sensitive signaling pathways in kidney diseases.


Assuntos
Injúria Renal Aguda/metabolismo , Mitocôndrias/metabolismo , Estresse Oxidativo , Processamento de Proteína Pós-Traducional , Espécies Reativas de Oxigênio/metabolismo , Insuficiência Renal Crônica/metabolismo , Injúria Renal Aguda/genética , Injúria Renal Aguda/patologia , Apoptose/genética , Ácidos Graxos/metabolismo , Humanos , Rim/metabolismo , Rim/patologia , Mitocôndrias/genética , Mitocôndrias/patologia , Dinâmica Mitocondrial , Mitofagia/genética , NADPH Oxidase 1/genética , NADPH Oxidase 1/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , Fosforilação Oxidativa , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia , Transdução de Sinais , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo
14.
Bioengineering (Basel) ; 8(8)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34436106

RESUMO

Streptomyces clavuligerus (S. clavuligerus) has been widely studied for its ability to produce clavulanic acid (CA), a potent inhibitor of ß-lactamase enzymes. In this study, S. clavuligerus cultivated in 2D rocking bioreactor in fed-batch operation produced CA at comparable rates to those observed in stirred tank bioreactors. A reduced model of S. clavuligerus metabolism was constructed by using a bottom-up approach and validated using experimental data. The reduced model was implemented for in silico studies of the metabolic scenarios arisen during the cultivations. Constraint-based analysis confirmed the interrelations between succinate, oxaloacetate, malate, pyruvate, and acetate accumulations at high CA synthesis rates in submerged cultures of S. clavuligerus. Further analysis using shadow prices provided a first view of the metabolites positive and negatively associated with the scenarios of low and high CA production.

15.
Rev. mex. trastor. aliment ; 11(1): 108-116, ene.-jun. 2021.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1570012

RESUMO

Resumen Los instrumentos para explorar los trastornos alimentarios han sido desarrollados y evaluados principalmente para la población Caucásica. Esta realidad ha limitado la disponibilidad de instrumentos validados y adaptados para la población latina/hispana. Debido al reto que representa para los investigadores en los Estados Unidos que estudian TA en latinos/hispanos, este artículo tiene como propósito revisar los instrumentos en español que hayan sido validados y adaptados para la población latina/hispana que vive en los Estados Unidos. También, se discutirán consideraciones psicométricas y culturales que tienen que incorporarse al utilizar un instrumento que haya sido construido y evaluado para una población o sub población en específico. Cuatro instrumentos, dos para establecer diagnósticos de TA (S-EDE y EDE-Q) y dos para explorar síntomas asociados a la insatisfacción corporal (BSQ y BICI) fueron identificados. La disponibilidad de instrumentos en español para el uso con latinos en los Estados Unidos es muy limitada y no han sido evaluados en todos los sub-grupos de latinos/hispanos que comprenden la población en los Estados Unidos. Esto constituye un reto para los clínicos e investigadores que trabajan con la comunidad latinos/hispanos con TA en los Estados Unidos. (palabras: 188).


Abstract The instruments to explore eating disorders (ED) have been developed and evaluated mainly for the Caucasian population. This situation has limited the availability of instruments validated and adapted for the Latino/Hispanic population. Due to the challenge it represents for researchers in the United States who study ED in Latinos/Hispanics, this article aims to review the instruments in Spanish that have been validated and adapted for the Latino/Hispanic population living in the United States. In addition, psychometric and cultural considerations that should be incorporated when using an instrument that has been constructed and evaluated for a specific population or sub-population will be discussed. Four instruments, two to establish diagnoses of ED (S-EDE and EDE-Q) and two to explore symptoms associated with body dissatisfaction (BSQ and BICI) were identified. The availability of instruments in Spanish for use with Latinos in the United States is very limited and has not been evaluated in all the subgroups of Latinos / Hispanics that comprise the population in the United States. This is a challenge for clinicians and researchers working with the Latino / Hispanic community with ED in the United States. (Words count: 186).

16.
J Exp Bot ; 72(17): 5987-6002, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-33649770

RESUMO

Thioredoxins (TRXs) are ubiquitous proteins engaged in the redox regulation of plant metabolism. Whilst the light-dependent TRX-mediated activation of Calvin-Benson cycle enzymes is well documented, the role of extraplastidial TRXs in the control of the mitochondrial (photo)respiratory metabolism has been revealed relatively recently. Mitochondrially located TRX o1 has been identified as a regulator of alternative oxidase, enzymes of, or associated with, the tricarboxylic acid (TCA) cycle, and the mitochondrial dihydrolipoamide dehydrogenase (mtLPD) involved in photorespiration, the TCA cycle, and the degradation of branched chain amino acids. TRXs are seemingly a major point of metabolic regulation responsible for activating photosynthesis and adjusting mitochondrial photorespiratory metabolism according to the prevailing cellular redox status. Furthermore, TRX-mediated (de)activation of TCA cycle enzymes contributes to explain the non-cyclic flux mode of operation of this cycle in illuminated leaves. Here we provide an overview on the decisive role of TRXs in the coordination of mitochondrial metabolism in the light and provide in silico evidence for other redox-regulated photorespiratory enzymes. We further discuss the consequences of mtLPD regulation beyond photorespiration and provide outstanding questions that should be addressed in future studies to improve our understanding of the role of TRXs in the regulation of central metabolism.


Assuntos
Arabidopsis , Arabidopsis/metabolismo , Oxirredução , Fotossíntese , Respiração , Tiorredoxinas/metabolismo
17.
Plant Cell Physiol ; 62(5): 798-814, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33693904

RESUMO

In Arabidopsis thaliana, two genes encode the E2 subunit of the 2-oxoglutarate dehydrogenase (2-OGDH), a multimeric complex composed of three subunits. To functionally characterize the isoforms of E2 subunit, we isolated Arabidopsis mutant lines for each gene encoding the E2 subunit and performed a detailed molecular and physiological characterization of the plants under controlled growth conditions. The functional lack of expression of E2 subunit isoforms of 2-OGDH increased plant growth, reduced dark respiration and altered carbohydrate metabolism without changes in the photosynthetic rate. Interestingly, plants from e2-ogdh lines also exhibited reduced seed weight without alterations in total seed number. We additionally observed that downregulation of 2-OGDH activity led to minor changes in the levels of tricarboxylic acid cycle intermediates without clear correlation with the reduced expression of specific E2-OGDH isoforms. Furthermore, the e2-ogdh mutant lines exhibited a reduction by up to 25% in the leaf total amino acids without consistent changes in the amino acid profile. Taken together, our results indicate that the two isoforms of E2 subunit play a similar role in carbon-nitrogen metabolism, in plant growth and in seed weight.


Assuntos
Arabidopsis/fisiologia , Carbono/metabolismo , Complexo Cetoglutarato Desidrogenase/metabolismo , Nitrogênio/metabolismo , Arabidopsis/crescimento & desenvolvimento , Regulação para Baixo , Regulação da Expressão Gênica de Plantas , Germinação , Complexo Cetoglutarato Desidrogenase/genética , Fotossíntese , Filogenia , Subunidades Proteicas , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Sementes/enzimologia , Sementes/crescimento & desenvolvimento
18.
Microorganisms ; 8(9)2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32824882

RESUMO

Streptomyces clavuligerus is a filamentous Gram-positive bacterial producer of the ß-lactamase inhibitor clavulanic acid. Antibiotics biosynthesis in the Streptomyces genus is usually triggered by nutritional and environmental perturbations. In this work, a new genome scale metabolic network of Streptomyces clavuligerus was reconstructed and used to study the experimentally observed effect of oxygen and phosphate concentrations on clavulanic acid biosynthesis under high and low shear stress. A flux balance analysis based on experimental evidence revealed that clavulanic acid biosynthetic reaction fluxes are favored in conditions of phosphate limitation, and this is correlated with enhanced activity of central and amino acid metabolism, as well as with enhanced oxygen uptake. In silico and experimental results show a possible slowing down of tricarboxylic acid (TCA) due to reduced oxygen availability in low shear stress conditions. In contrast, high shear stress conditions are connected with high intracellular oxygen availability favoring TCA activity, precursors availability and clavulanic acid (CA) production.

19.
Rev. mex. trastor. aliment ; 10(3): 261-273, ene.-jun. 2020. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1377020

RESUMO

Resumen El propósito de este trabajo fue hacer la detección de probables casos de trastornos de la conducta alimentaria (TCA) en adolescentes, así como analizar su relación con los hábitos alimentarios (HA) dentro del contexto escolar. Participaron 3,144 alumnos/as (49.7% chicas y 50.3% chicos), con edades entre 13 y 17 años (M = 14.41, DE = 0.79). Fueron registradas distintas variables: sociodemográficas, índice de masa corporal (IMC) e ingesta alimentaria, además de aplicar el Cuestionario de Actitudes Alimentarias (EAT-40) y el Cuestionario de Imagen Corporal (BSQ). Se identificaron diferencias significativas en EAT-40 y BSQ, con una mayor proporción de chicas vs. chicos que superaron el punto de corte. Respecto al IMC, aunque la mayoría estaba en normopeso, el 17.6% tuvo infrapeso, 20.4% sobrepeso y 7.1% obesidad. El 5.6% de todos los participantes fueron identificados como probables casos de TCA, con una mayor proporción de mujeres (9.6%) que de hombres (1.8%). No hubo correlación con los HA, pero sí mayor proporción de chicas que consumían menos alimentos y bebidas durante el desayuno y el recreo. Un dato alarmante es que 5.6% de las chicas y 2.5% de los chicos no consumían nada durante toda la mañana escolar.


Abstract A study of detection of probable cases of eating disorders (ED) in teenagers, studying their possible relationship with their dietary habits (DH) in the school context has been carried out. The participants were 3,144 students (49.7 % girls and 50.3 % boys) aged between 13 and 17 years old (M = 14.41, SD = 0.79). Different variables were recorded: sociodemographic, body mass index (BMI) and dietary intake, in addition to applying the Eating Attitudes Questionnaire (EAT-40) and the Body Shape Questionnaire (BSQ). Significant differences were identified in EAT-40 and BSQ, with a greater proportion of girls vs. boys exceeding the cut-off point. Regarding the BMI, although most were in normal weight, the 17.6% were underweight, 20.4% overweight and 7.1% obese. Based on all the data, 5.6% of all participants were identified as probable cases of ED, with a higher proportion of women (9.6%) that men (1.8%). There was no correlation with DH, but there were a higher proportion of girls who consumed less food and beverages during breakfast and recess. An alarming fact is that 5.6% of girls and 2.5% of boys did not consume anything during the whole school time.

20.
Trends psychiatry psychother. (Impr.) ; 42(1): 39-47, Jan.-Mar. 2020. tab
Artigo em Inglês | LILACS | ID: biblio-1099404

RESUMO

Abstract Introduction The Questionnaire on Eating and Weight Patterns-5 (QEWP-5) is a self-report instrument developed to screen individuals for binge eating disorder (BED), as defined by the DSM-5. However, this version of the instrument had not been adapted for the Brazilian population. Objective To describe translation and cross-cultural adaptation of the QEWP-5 into Brazilian Portuguese. Methods Translation and cross-cultural adaptation of the QEWP-5 included the following steps: forward translation, comparison of translations and a synthesis version, blind back-translations, comparison of the back translations with the original version, and a comprehensibility test. The comprehensibility test was conducted with a sample of 10 participants with BED or bulimia nervosa and 10 eating disorders experts. Additionally, a Content Validity Index (CVI-I) was calculated for each item and then averaged to produce an index for the entire scale (CVI-Ave), to assess content equivalence. Results Some inconsistencies emerged during the process of translation and adaptation. However, the expert committee solved them by consensus. The participants of the comprehensibility test understood the Brazilian version of QEWP-5 well. Only 2 patients (20%) had doubts about items related to subjective binge eating episodes. Content equivalence analysis rated all items relevant, with CVI-I ranging from 0.8 to 1.0 and an overall CVI-Ave of 0.94. In view of the good overall assessment of the pre-final version of the instrument, additional changes were not made to the final version. Conclusion The Brazilian version of the QEWP-5 was cross-culturally adapted and was well understood by the target population. Further studies are required to assess its psychometric properties.


Resumo Introdução O Questionnaire on Eating and Weight Patterns-5 (QEWP-5) - Questionário sobre Padrões de Alimentação e Peso-5 - é um instrumento auto preenchível utilizado para rastrear indivíduos com transtorno da compulsão alimentar (TCA) segundo os critérios do DSM-5. Entretanto, essa versão do instrumento ainda não foi adaptada para a população brasileira. Objetivo Descrever a tradução e adaptação transcultural do QEWP-5 para a língua portuguesa. Métodos O processo de adaptação transcultural incluiu as seguintes etapas: tradução, comparação das traduções e elaboração da versão síntese, retro-tradução com cegamento, comparação das retrotraduções com a versão original, e teste de compreensibilidade. O teste de compreensibilidade foi conduzido em uma amostra de 10 indivíduos com TCA ou bulimia nervosa e 10 especialistas em Transtornos Alimentares. Adicionalmente, foram calculados o Índice de Validade de Conteúdo para cada item (IVC-I) e para a média da escala (IVC-M), para avaliar a equivalência de conteúdo. Resultados Durante o processo de tradução e adaptação surgiram algumas discrepâncias. No entanto, elas foram solucionadas por meio de consenso do comitê de especialistas. No teste de compreensibilidade, a versão brasileira do QEWP-5 foi bem compreendida pelos participantes. Somente 2 participantes (20%) apresentaram questionamentos sobre itens relacionados aos episódios de compulsão alimentar subjetivos. Em relação à equivalência de conteúdo, todos os itens foram avaliados como relevantes, com o IVC-I variando de 0,8 a 1,0. Ademais, o IVC-M foi 0,94. Considerando a boa avaliação geral da versão pré-final do instrumento, não foram realizadas alterações na versão final. Conclusão A versão brasileira do QEWP-5 foi adaptada transculturalmente e bem compreendida pela população-alvo. Estudos adicionais são necessários para avaliar suas propriedades psicométricas.


Assuntos
Adulto , Humanos , Escalas de Graduação Psiquiátrica/normas , Psicometria/normas , Peso Corporal , Transtornos da Alimentação e da Ingestão de Alimentos/diagnóstico , Psicometria/instrumentação , Psicometria/métodos , Brasil , Manual Diagnóstico e Estatístico de Transtornos Mentais , Bulimia Nervosa/diagnóstico , Transtorno da Compulsão Alimentar/diagnóstico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA