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1.
J Agric Food Chem ; 69(31): 8634-8648, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34339211

RESUMO

The monocot lineage-specific miR528 was previously established as a multistress regulator. However, it remains largely unclear how miR528 participates in response to salinity stress in rice. Here, we show that miR528 positively regulates rice salt tolerance by down-regulating a gene encoding l-ascorbate oxidase (AO), thereby bolstering up the AO-mediated abscisic acid (ABA) synthesis and ROS scavenging. Overexpression of miR528 caused a substantial increase in ascorbic acid (AsA) and ABA contents but a significant reduction in ROS accumulation, resulting in the enhanced salt tolerance of rice plants. Conversely, knockdown of miR528 or overexpression of AO stimulated the expression of the AO gene, hence lowering the level of AsA, a critical antioxidant that promotes the ABA content but reduces the ROS level, and then compromising rice tolerance to salinity. Together, the findings reveal a novel mechanism of the miR528-AO module-mediated salt tolerance by modulating the processes of AsA and ABA metabolism as well as ROS detoxification, which adds a new regulatory role to the miR528-AO stress defense pathway in rice.


Assuntos
Ácido Abscísico/metabolismo , Ácido Ascórbico/metabolismo , MicroRNAs/genética , Oryza , Tolerância ao Sal , Ascorbato Oxidase , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tolerância ao Sal/genética , Estresse Fisiológico
2.
Int J Mol Sci ; 22(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201662

RESUMO

Gene expression and phytohormone contents were measured in response to elevating ascorbate in the absence of other confounding stimuli such as high light and abiotic stresses. Young Arabidopsis plants were treated with 25 mM solutions of l-galactose pathway intermediates l-galactose (l-gal) or l-galactono-1,4-lactone (l-galL), as well as L-ascorbic acid (AsA), with 25 mM glucose used as control. Feeding increased rosette AsA 2- to 4-fold but there was little change in AsA biosynthetic gene transcripts. Of the ascorbate recycling genes, only Dehydroascorbate reductase 1 expression was increased. Some known regulatory genes displayed increased expression and included ANAC019, ANAC072, ATHB12, ZAT10 and ZAT12. Investigation of the ANAC019/ANAC072/ATHB12 gene regulatory network revealed a high proportion of ABA regulated genes. Measurement of a subset of jasmonate, ABA, auxin (IAA) and salicylic acid compounds revealed consistent increases in ABA (up to 4.2-fold) and phaseic acid (PA; up to 5-fold), and less consistently certain jasmonates, IAA, but no change in salicylic acid levels. Increased ABA is likely due to increased transcripts for the ABA biosynthetic gene NCED3. There were also smaller increases in transcripts for transcription factors ATHB7, ERD1, and ABF3. These results provide insights into how increasing AsA content can mediate increased abiotic stress tolerance.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/fisiologia , Ácido Ascórbico/metabolismo , Glutationa Transferase/genética , Reguladores de Crescimento de Plantas/metabolismo , Estresse Fisiológico/fisiologia , Ácido Abscísico/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/metabolismo , Ascorbato Oxidase/genética , Ascorbato Oxidase/metabolismo , Ácido Ascórbico/genética , Ciclopentanos/metabolismo , Galactose/farmacologia , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Glutationa Transferase/metabolismo , Ácidos Hexurônicos/metabolismo , Ácidos Indolacéticos/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/genética , Sesquiterpenos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
3.
Genes (Basel) ; 12(5)2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066421

RESUMO

Ascorbic acid (AsA) is an essential multifaceted phytonutrient for both the human diet and plant growth. Optimum levels of AsA accumulation combined with balanced redox homeostasis are required for normal plant development and defense response to adverse environmental stimuli. Notwithstanding its moderate AsA levels, tomatoes constitute a good source of vitamin C in the human diet. Therefore, the enhancement of AsA levels in tomato fruit attracts considerable attention, not only to improve its nutritional value but also to stimulate stress tolerance. Genetic regulation of AsA concentrations in plants can be achieved through the fine-tuning of biosynthetic, recycling, and transport mechanisms; it is also linked to changes in the whole fruit metabolism. Emerging evidence suggests that tomato synthesizes AsA mainly through the l-galactose pathway, but alternative pathways through d-galacturonate or myo-inositol, or seemingly unrelated transcription and regulatory factors, can be also relevant in certain developmental stages or in response to abiotic factors. Considering the recent advances in our understanding of AsA regulation in model and other non-model species, this review attempts to link the current consensus with novel technologies to provide a comprehensive strategy for AsA enhancement in tomatoes, without any detrimental effect on plant growth or fruit development.


Assuntos
Ácido Ascórbico/metabolismo , Lycopersicon esculentum/metabolismo , Estresse Fisiológico , Ácido Ascórbico/genética , Biofortificação/métodos , Lycopersicon esculentum/genética , Lycopersicon esculentum/normas , Melhoramento Vegetal/métodos
4.
Nutrients ; 13(5)2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-34063417

RESUMO

Severe and long-term vitamin C deficiency can lead to fatal scurvy, which is fortunately considered rare today. However, a moderate state of vitamin C (vitC) deficiency (hypovitaminosis C)-defined as a plasma concentration below 23 µM-is estimated to affect up to 10% of the population in the Western world, albeit clinical hallmarks in addition to scurvy have not been linked to vitC deficiency. The brain maintains a high vitC content and uniquely high levels during deficiency, supporting vitC's importance in the brain. Actions include both antioxidant and co-factor functions, rendering vitamin C deficiency likely to affect several targets in the brain, and it could be particularly significant during development where a high cellular metabolism and an immature antioxidant system might increase sensitivity. However, investigations of a non-scorbutic state of vitC deficiency and effects on the developing young brain are scarce. This narrative review provides a comprehensive overview of the complex mechanisms that regulate vitC homeostasis in vivo and in the brain in particular. Functions of vitC in the brain and the potential consequences of deficiency during brain development are highlighted, based primarily on findings from experimental animal models. Perspectives for future investigations of vitC are outlined.


Assuntos
Deficiência de Ácido Ascórbico/sangue , Ácido Ascórbico/metabolismo , Encéfalo/metabolismo , Escorbuto/metabolismo , Animais , Antioxidantes/metabolismo , Ácido Ascórbico/sangue , Ácido Ascórbico/farmacocinética , Deficiência de Ácido Ascórbico/genética , Encéfalo/crescimento & desenvolvimento , Carnitina , Ácidos Graxos Insaturados/metabolismo , Homeostase , Humanos , Camundongos Knockout , Modelos Animais , Neuroglia/metabolismo , Neurônios/metabolismo , Transportadores de Sódio Acoplados à Vitamina C/genética
5.
Int J Biol Macromol ; 183: 2100-2108, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34102235

RESUMO

Effect of edible coatings of gum Arabic, carrageenan and xanthan gum containing lemon grass essential oil 1% w/v on postharvest quality of strawberry was studied under refrigeration for a period of 12 days. Results showed all the three coatings maintained fruit quality parameters during storage compared to control. Among all the coatings, carrageenan coated fruits showed delayed weight loss (10.1 to 8%), decay percentage (78.42 to 14.29%), retained ascorbic acid (0.15 to 0.27 g kg-1), antioxidant activity (18.17 to 25.85%), firmness (9.07 to 12.43 N), L* (32.38 to 40.42), a* (16.08 to 17.22) and b* (27.36 to 33.54). Carrageenan gum also showed lowest cellulase activity (0.03 units h-1 mg protein-1), pectin methylesterase activity (1.13 A620 min-1 mg protein-1) and ß-galactosidase activity (0.51 µmol min-1 mg protein-1), while showed maximum reduction in polygalacturonase activity (0.07 units h-1 mg protein-1) at the end of storage. Carrageenan gum was found effective in retention of anthocyanins and phenolic compounds during storage. Coatings loaded with antimicrobial agent inhibited psychrophilic bacteria, yeast and mold growth. It is concluded that carrageenan gum could better retain strawberry quality up to 12 days under refrigeration.


Assuntos
Anti-Infecciosos/química , Carragenina/química , Filmes Comestíveis , Embalagem de Alimentos , Conservação de Alimentos , Fragaria/enzimologia , Frutas/enzimologia , Goma Arábica/química , Óleos Vegetais/química , Polissacarídeos Bacterianos/química , Antocianinas/metabolismo , Anti-Infecciosos/farmacologia , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Celulase/metabolismo , Cymbopogon , Microbiologia de Alimentos , Armazenamento de Alimentos , Fragaria/microbiologia , Frutas/microbiologia , Fenóis/química , Óleos Vegetais/isolamento & purificação , Óleos Vegetais/farmacologia , Poligalacturonase/metabolismo , Refrigeração , Fatores de Tempo , beta-Galactosidase/metabolismo
6.
Int J Mol Sci ; 22(9)2021 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-33947005

RESUMO

Beneficial metabolic effects of inorganic nitrate (NO3-) and nitrite (NO2-) in type 2 diabetes mellitus (T2DM) have been documented in animal experiments; however, this is not the case for humans. Although it has remained an open question, the redox environment affecting the conversion of NO3- to NO2- and then to NO is suggested as a potential reason for this lost-in-translation. Ascorbic acid (AA) has a critical role in the gastric conversion of NO2- to NO following ingestion of NO3-. In contrast to AA-synthesizing species like rats, the lack of ability to synthesize AA and a lower AA body pool and plasma concentrations may partly explain why humans with T2DM do not benefit from NO3-/NO2- supplementation. Rats also have higher AA concentrations in their stomach tissue and gastric juice that can significantly potentiate gastric NO2--to-NO conversion. Here, we hypothesized that the lack of beneficial metabolic effects of inorganic NO3- in patients with T2DM may be at least in part attributed to species differences in AA metabolism and also abnormal metabolism of AA in patients with T2DM. If this hypothesis is proved to be correct, then patients with T2DM may need supplementation of AA to attain the beneficial metabolic effects of inorganic NO3- therapy.


Assuntos
Ácido Ascórbico/uso terapêutico , Diabetes Mellitus Tipo 2/metabolismo , Nitratos/farmacocinética , Oxirredutases do Álcool/deficiência , Animais , Arginina/metabolismo , Ácido Ascórbico/metabolismo , Ácido Ascórbico/farmacologia , Deficiência de Ácido Ascórbico/complicações , Deficiência de Ácido Ascórbico/tratamento farmacológico , Ensaios Clínicos como Assunto , Diabetes Mellitus Tipo 2/complicações , Dieta , Suco Gástrico/metabolismo , Mucosa Gástrica/metabolismo , Glucose/metabolismo , Cobaias , Homeostase , Humanos , Insulina/metabolismo , Camundongos , Modelos Animais , Nitratos/administração & dosagem , Nitratos/metabolismo , Nitratos/uso terapêutico , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Nitritos/metabolismo , Nitritos/farmacocinética , Necessidades Nutricionais , Oxirredução , Ratos , Especificidade da Espécie
7.
Ecotoxicol Environ Saf ; 217: 112248, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33901782

RESUMO

Melatonin (Mel), a powerful antioxidant that has the ability to regulate physiological and biochemical processes in plants under abiotic stresses. However, its roles in pesticide detoxification is poorly understood. Herein, selecting leaf spraying insecticide imidacloprid (IMD) as the model, we demonstrated the detoxification mechanism underlying root pretreatment of Mel on IMD in cucumber. IMD treatment affected the primary light conversion efficiency of photosystem II (Fv/Fm), reduced the quantum yield, and increased hydrogen peroxide and superoxide anions contents as well as the levels of membrane lipid peroxidation, indicating that excessive IMD treatment induces oxidative stress. Nonetheless, by increasing the appropriate levels of exogenous Mel, the photosynthesis of cucumber under IMD treatment reached the control levels, effectively removing reactive oxygen species. Furthermore, the content and ratio of ascorbate (AsA) and glutathione (GSH) were decreased under IMD treatment; Mel treatment enhanced the AsA/DHA and GSH/GSSG ratios, as well as the activities of MDHAR, DHAR and GR, suggesting that Mel could alleviate oxidative stress of cucumber treated with IMD by regulating the ascorbic acid-glutathione cycle. Importantly, IMD degradation rate and glutathione S-transferase (GST) activity increased after Mel treatment. The levels of transcripts encoding antioxidant enzymes GPX and GST (GST1,2 and 3) were also increased, indicating that Mel accelerated IMD degradation. These results suggest that Mel plays an important role in the detoxification of IMD by promoting GST activity and transcription and the AsA-GSH cycle, thus providing an approach for plants to reduce IMD residue through the plant's own detoxification mechanism.


Assuntos
Cucumis sativus/fisiologia , Glutationa/metabolismo , Inseticidas/toxicidade , Melatonina/metabolismo , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Cucumis sativus/metabolismo , Homeostase/efeitos dos fármacos , Homeostase/fisiologia , Peróxido de Hidrogênio/metabolismo , Inativação Metabólica/efeitos dos fármacos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos
8.
Biomolecules ; 11(2)2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33670537

RESUMO

The effects of nitric oxide (NO) as 100 µM sodium nitroprusside (SNP, NO donor) on photosynthetic-nitrogen use efficiency (NUE), photosynthetic-sulfur use efficiency (SUE), photosynthesis, growth and agronomic traits of rice (Oryza sativa L.) cultivars, Taipie-309 (high photosynthetic-N and SUE) and Rasi (low photosynthetic-N and SUE) were investigated under high temperature stress (40 °C for 6 h). Plants exposed to high temperature stress caused significant reduction in photosynthetic activity, use efficiency of N and S, and increment in H2O2 and thiobarbituric acid reactive substance (TBARS) content. The drastic effects of high temperature stress were more pronounced in cultivar Rasi than Taipie-309. However, foliar spray of SNP decreased the high temperature induced H2O2 and TBARS content and increased accumulation of proline and activity of ascorbate-glutathione cycle that collectively improved tolerance to high temperature stress more effectively in Taipie-309. Exogenously applied SNP alleviated the high temperature induced decrease in photosynthesis through maintaining higher photosynthetic-NUE and photosynthetic-SUE, activity of ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco), and synthesis of reduced glutathione (GSH). The use of 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide (cPTIO, NO scavenger) substantiated the study that in the absence of NO oxidative stress increased, while NO increased photosynthetic-NUE and photosynthetic-SUE, net photosynthesis and plant dry mass. Taken together, the present investigation reveals that NO increased heat stress tolerance and minimized high temperature stress adversaries more effectively in cultivar Taipie-309 than Rasi by enhancing photosynthetic-NUE and SUE and strengthening the antioxidant defense system.


Assuntos
Ácido Ascórbico/metabolismo , Glutationa/metabolismo , Óxido Nítrico/metabolismo , Nitrogênio/metabolismo , Oryza/efeitos dos fármacos , Oryza/metabolismo , Enxofre/metabolismo , Nitroprussiato/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Temperatura
9.
Arch Insect Biochem Physiol ; 106(4): e21783, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33719082

RESUMO

Vitamin C (VC) is an essential nutrient for many animals. However, whether insects, including Bombyx mori, can synthesize VC remains unclear. In this article, the optimized HPLC method was used to determine the content of l-ascorbic acid (AsA) in silkworm eggs, larvae and pupae, and the activity of l-gulono-1,4-lactone oxidase (GULO), a key enzyme in VC synthesis. The RNA interference method was used to determine the effect of the BmGulo-like gene on embryonic development and GULO activity in the pupal fat body. The AsA content increased significantly during E144 h-E168 h in the late embryonic stage and P48 h-P144 h in the middle-late pupal stage, in which exogenous VC was not ingested. Furthermore, the body AsA content in larvae fed VC-free feed also increased with larval stage. The GULO enzymatic activity was present in eggs and the fat bodies of larvae and pupae, even when the larvae were reared with fresh mulberry leaves. Moreover, the activity was higher in the later embryonic stages (E144 h-E168 h) and the early pupal stage (before P24 h). The GULO activity in the pupal fat body dramatically decreased when the screened BmGulo-like gene (BGIBMGA005735) was knocked down with small interfering RNA; in addition, the survival rate and hatching rate of eggs significantly decreased 21% and 44%, respectively, and embryonic development was delayed. Thus, Bombyx mori can synthesize AsA through the l-gulose pathway, albeit with low activity, and this synthesis ability varies with developmental stages.


Assuntos
Ácido Ascórbico/metabolismo , Bombyx/metabolismo , Animais , Bombyx/crescimento & desenvolvimento , Hexoses/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Açúcares Ácidos/metabolismo
10.
Nutrients ; 13(2)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672967

RESUMO

The process of obtaining ascorbic acid (AA) via intestinal absorption and blood circulation is carrier-mediated utilizing the AA transporters SVCT1 and SVCT2, which are expressed in the intestine and brain (SVCT2 in abundance). AA concentration is decreased in Alzheimer's disease (AD), but information regarding the status of intestinal AA uptake in the AD is still lacking. We aimed here to understand how AA homeostasis is modulated in a transgenic mouse model (5xFAD) of AD. AA levels in serum from 5xFAD mice were markedly lower than controls. Expression of oxidative stress response genes (glutathione peroxidase 1 (GPX1) and superoxide dismutase 1 (SOD1)) were significantly increased in AD mice jejunum, and this increase was mitigated by AA supplementation. Uptake of AA in the jejunum was upregulated. This increased AA transport was caused by a marked increase in SVCT1 and SVCT2 protein, mRNA, and heterogeneous nuclear RNA (hnRNA) expression. A significant increase in the expression of HNF1α and specific protein 1 (Sp1), which drive SLC23A1 and SLC23A2 promoter activity, respectively, was observed. Expression of hSVCT interacting proteins GRHPR and CLSTN3 were also increased. SVCT2 protein and mRNA expression in the hippocampus of 5xFAD mice was not altered. Together, these investigations reveal adaptive up-regulation of intestinal AA uptake in the 5xFAD mouse model.


Assuntos
Doença de Alzheimer/metabolismo , Ácido Ascórbico/metabolismo , Jejuno/metabolismo , Transportadores de Sódio Acoplados à Vitamina C/metabolismo , Regulação para Cima/genética , Oxirredutases do Álcool/metabolismo , Animais , Transporte Biológico/genética , Proteínas de Ligação ao Cálcio/metabolismo , Suplementos Nutricionais , Modelos Animais de Doenças , Glutationa Peroxidase/metabolismo , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Hipocampo/metabolismo , Homeostase/genética , Absorção Intestinal/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Transgênicos , Estresse Oxidativo/genética , RNA Mensageiro/metabolismo , Superóxido Dismutase-1/metabolismo
11.
Food Chem ; 352: 129458, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33714166

RESUMO

We investigated the effect of exogenous glutathione (GSH) on chilling injury (CI) in postharvest bell pepper fruits stored at low temperature and explored the mechanism of this treatment from the perspective of the ascorbate-glutathione (AsA-GSH) cycle. Compared with the control, fruits treated with exogenous GSH before refrigeration displayed only slight CI symptoms and mitigated CI-induced cell damage after 10 d. Moreover, the treated peppers had lower lipid peroxidation product, H2O2, and O2- content than those did the control. Glutathione treatment enhanced the ascorbate-glutathione cycle by upregulating CaAPX1, CaGR2, CaMDHAR1, and CaDHAR1 and the antioxidant enzymes APX, GR, and MDHAR associated with the ascorbate-glutathione cycle. Glutathione treatment also increased ascorbate and glutathione concentrations. Taken together, our results showed that exogenous GSH treatment could alleviate CI in pepper fruits during cold storage by triggering the AsA-GSH cycle and improving antioxidant capacity.


Assuntos
Ácido Ascórbico/metabolismo , Capsicum/efeitos dos fármacos , Capsicum/metabolismo , Temperatura Baixa , Glutationa/farmacologia , Frutas/efeitos dos fármacos , Frutas/metabolismo , Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/metabolismo
12.
Plant Cell Environ ; 44(5): 1522-1533, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547695

RESUMO

Auxin induced in root culture (AIR12) is a single gene in Arabidopsis and codes for a mono-heme cytochrome b, but it is unknown whether plant AIR12 is involved in abiotic stress responses. MfAIR12 was identified from Medicago falcata that is legume germplasm with great cold tolerance. Transcript levels of MfAIR12 and its homolog MtAIR12 from Medicago truncatula was induced under low temperature. Overexpression of MfAIR12 led to the accumulation of H2 O2 in apoplast and enhanced cold tolerance, which was blocked by H2 O2 scavengers, indicating that the increased cold tolerance was dependent upon the accumulated H2 O2 . In addition, declined cold tolerance was observed in Arabidopsis mutant air12, which could be restored by expressing MfAIR12. Compared to the wild type, higher levels of ascorbic acid and ascorbate redox state, as well as transcripts of the C repeat/dehydration responsive element-binding factor (CBF) transcription factors and their downstream cold-responsive genes, were observed in MfAIR12 transgenic lines, but lower levels of those in air12 mutant. It is suggested AIR12 confers cold tolerance as a result of the altered H2 O2 in the apoplast that is signaling in the regulation of CBF cold response pathway and ascorbate homeostasis.


Assuntos
Adaptação Fisiológica , Ácido Ascórbico/metabolismo , Temperatura Baixa , Homeostase , Medicago/fisiologia , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Medicago/genética , Mutação/genética , Oxirredução , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Tabaco/genética
13.
J Photochem Photobiol B ; 216: 112142, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33592357

RESUMO

In the present study, the effects of elevated UV-B (eUVB; ambient ± 7.2 kJ m-2 day-1) were evaluated on the biochemical and metabolic profile of Adhatoda vasica Nees. (an indigenous medicinal plant) at different growth stages. The results showed reduction in superoxide radical production rate, whereas increase in the content of hydrogen peroxide which was also substantiated by the histochemical localization. Malondialdehyde content, which is a measure of oxidative stress, did not show significant changes at any of the growth stages however photosynthetic rate and chlorophyll content showed reduction at all growth stages under eUV-B exposure. Increased activities of the enzymatic and non-enzymatic antioxidants were noticed except ascorbic acid, which was reduced under eUV-B exposure. The metabolic profile of A. vasica revealed 43 major compounds (assigned under different classes) at different growth stages. Triterpenes, phytosterols, unsaturated fatty acids, diterpenes, tocopherols, and alkaloids showed increment, whereas reduction in saturated fatty acids and sesquiterpenes were observed under eUV-B treatment. Vasicinone and vasicoline, the two important alkaloids of A. vasica, showed significant induction under eUV-B exposure as compared to control. Treatment of eUV-B leads to the synthesis of some new compounds, such as oridonin oxide (diterpene) and α-Bisabolol oxide-B (sesquiterpene), which possess potent anti-inflammatory and anticancerous activities. The study displayed that differential crosstalk between antioxidants and secondary metabolites at different growth stages, were responsible for providing protection to A. vasica against eUV-B induced oxidative stress and enhancing its medicinal properties.


Assuntos
Antioxidantes/metabolismo , Justicia, Planta/metabolismo , Metaboloma/efeitos da radiação , Extratos Vegetais/metabolismo , Plantas Medicinais/metabolismo , Antioxidantes/efeitos da radiação , Ácido Ascórbico/metabolismo , Clorofila/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Peróxido de Hidrogênio/metabolismo , Justicia, Planta/efeitos da radiação , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos da radiação , Fitosteróis/metabolismo , Plantas Medicinais/efeitos da radiação , Metabolismo Secundário/efeitos da radiação , Fatores de Tempo , Tocoferóis/metabolismo , Triterpenos/metabolismo , Raios Ultravioleta
14.
PLoS One ; 16(2): e0246678, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33544780

RESUMO

Na+,K+-ATPase is a crucial protein responsible for maintaining the electrochemical gradients across the cell membrane. The Na+,K+-ATPase is comprised of catalytic α, ß, and γ subunits. In adult brains, the α3 subunit, encoded by ATP1A3, is predominantly expressed in neurons, whereas the α2 subunit, encoded by ATP1A2, is expressed in glial cells. In foetal brains, the α2 is expressed in neurons as well. Mutations in α subunits cause a variety of neurologic disorders. Notably, the onset of symptoms in ATP1A2- and ATP1A3-related neurologic disorders is usually triggered by physiological or psychological stressors. To gain insight into the distinct roles of the α2 and α3 subunits in the developing foetal brain, whose developmental dysfunction may be a predisposing factor of neurologic disorders, we compared the phenotypes of mouse foetuses with double homozygous knockout of Atp1a2 and Atp1a3 (α2α3-dKO) to those with single knockout. The brain haemorrhage phenotype of α2α3-dKO was similar to that of homozygous knockout of the gene encoding ascorbic acid (ASC or vitamin C) transporter, SVCT2. The α2α3-dKO brain showed significantly decreased level of ASC compared with the wild-type (WT) and single knockout. We found that the ASC content in the basal ganglia and cerebellum was significantly lower in the adult Atp1a3 heterozygous knockout mouse (α3-HT) than in the WT. Interestingly, we observed a significant decrease in the ASC level in the basal ganglia and cerebellum of α3-HT in the peripartum period, during which mice are under physiological stress. These observations indicate that the α2 and α3 subunits independently contribute to the ASC level in the foetal brain and that the α3 subunit contributes to ASC transport in the adult basal ganglia and cerebellum. We propose that decreases in ASC levels may affect neural network development and are linked to the pathophysiology of ATP1A2- and ATP1A3-related neurologic disorders.


Assuntos
Ácido Ascórbico/metabolismo , Rede Nervosa/fisiopatologia , Doenças do Sistema Nervoso/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Camundongos , Camundongos Knockout , Rede Nervosa/metabolismo , Doenças do Sistema Nervoso/genética , Doenças do Sistema Nervoso/patologia , Fenótipo , Vitaminas/metabolismo
15.
Fish Physiol Biochem ; 47(2): 617-637, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33611775

RESUMO

A 45-day feeding trial was conducted to evaluate the effect of dietary jamun tree leaf (JL) on the antioxidant defence system-based disease resistance in juveniles of Trachinotus blochii. The juveniles of snubnose pompano were distributed into four treatment groups in triplicates. Each treatment was fed with a diet containing either 0 (0JL), 0.5 (0.5JL), 1 (1JL) and 1.5% JL (1.5JL) in the feed. After feeding trial, the fishes were experimentally infected with Vibrio parahaemolyticus. The activities of oxidative stress enzymes such as superoxide dismutase and catalase were found to be increasing with increasing level of dietary JL incorporation, and the lower value was witnessed in control group in pre- and post-challenge. After challenge, the alanine and aspartate aminotransferase activities in all the treatments were significantly increased (P < 0.05) than the pre-challenge condition and exhibited reverse trend with the antioxidant enzymes. The alkaline and acid phosphatase activities were found higher in 1.5JL group and showed significant difference (P < 0.05) among the treatments. The respiratory burst activity and liver glycogen content showed an increasing trend as the level of inclusion of JL increased in the diet. The acetylcholinesterase activity was significantly plunged (P < 0.05) after experimental infection, and JL diet fed groups showed better activity. After experimental infection with V. parahaemolyticus, the highest relative percentage of survival was observed in 1JL and 1.5JL groups. Hence, dietary supplementation of jamun tree leaf at the level of 1% is adequate to reduce the oxidative stress and improved the innate immune status through antioxidant defence system.


Assuntos
Ração Animal/análise , Antioxidantes/metabolismo , Dieta/veterinária , Peixes , Estresse Oxidativo , Folhas de Planta/química , Syzygium/química , Animais , Ácido Ascórbico/metabolismo , Fígado/metabolismo , Músculo Esquelético/metabolismo , Fitoterapia
16.
Mol Biol Rep ; 48(2): 1651-1658, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33580460

RESUMO

SVCT2, Sodium-dependent Vitamin C Transporter 2, uniquely transports ascorbic acid (also known as vitamin C and ascorbate) into all types of cells. Vitamin C is an essential nutrient that must be obtained through the diet and plasma levels are tightly regulated by transporter activity. Vitamin C plays an important role in antioxidant defenses and is a cofactor for many enzymes that enable hormone synthesis, oxygen sensing, collagen synthesis and epigenetic pathways. Although SVCT2 has various functions, regulation of its expression/activity remains poorly understood. We found a p53-binding site, within the SVCT2 promoter, using a transcription factor binding-site prediction tool. In this study, we show that p53 can directly repress SVCT2 transcription by binding a proximal- (~-185 to -171 bp) and a distal- (~-1800 to -1787 bp) p53-responsive element (PRE), Chromatin immunoprecipitation assays showed that PRE-bound p53 interacts with the corepressor-histone deacetylase 3 (HDAC3), resulting in deacetylation of histones Ac-H4, at the proximal promoter, resulting in transcriptional silencing of SVCT2. Overall, our data suggests that p53 is a potent transcriptional repressor of SVCT2, a critical transporter of diet-derived ascorbic acid, across the plasma membranes of numerous essential tissue cell types.


Assuntos
Antioxidantes/metabolismo , Histona Desacetilases/genética , Transportadores de Sódio Acoplados à Vitamina C/genética , Proteína Supressora de Tumor p53/genética , Animais , Ácido Ascórbico/genética , Ácido Ascórbico/metabolismo , Sítios de Ligação/genética , Cromatina/genética , Fibroblastos , Células Hep G2 , Humanos , Camundongos , Ligação Proteica , Proteínas Repressoras/genética , Transportadores de Sódio Acoplados à Vitamina C/antagonistas & inibidores
17.
BMC Plant Biol ; 21(1): 112, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627094

RESUMO

BACKGROUND: Abscisic acid (ABA) plays an important role in plant abiotic stress responses, and ABA INSENSITIVE 4 (ABI4) is a pivotal transcription factor in the ABA signaling pathway. In Arabidopsis, ABI4 negatively regulates salt tolerance; however, the mechanism through which ABI4 regulates plant salt tolerance is poorly understood. Our previous study showed that ABI4 directly binds to the promoter of the VITAMIN C DEFECTIVE 2 (VTC2) gene, inhibiting the transcription of VTC2 and ascorbic acid (AsA) biosynthesis. RESULTS: In the present study, we found that treatment with exogenous AsA could alleviate salt stress sensitivity of ABI4-overexpressing transgenic plants. The decreased AsA content and increased reactive oxygen species (ROS) levels in ABI4-overexpressing seedlings under salt treatment indicated that AsA-promoted ROS scavenging was related to ABI4-mediated salt tolerance. Gene expression analysis showed that ABI4 was induced at the early stage of salt stress, giving rise to reduced VTC2 expression. Accordingly, the abundance of the VTC2 protein decreased under the same salt stress conditions, and was absent in the ABI4 loss-of-function mutants, suggesting that the transcriptional inhibition of ABI4 on VTC2 resulted in the attenuation of VTC2 function. In addition, other encoding genes in the AsA biosynthesis and recycling pathways showed different responses to salt stress, demonstrating that AsA homeostasis is complicated under salinity stress. CONCLUSIONS: This study elucidates the negative modulation of ABI4 in salt stress tolerance through the regulation of AsA biosynthesis and ROS accumulation in plants.


Assuntos
Ácido Abscísico/metabolismo , Arabidopsis/genética , Arabidopsis/fisiologia , Ácido Ascórbico/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Tolerância ao Sal/genética , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas
18.
Int J Biol Macromol ; 173: 532-540, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33482210

RESUMO

Sucrose phosphorylase (SPase, EC2.4.1.7) is a promising transglycosylation biocatalyst used for producing glycosylated compounds that are widely used in the food, cosmetics, and pharmaceutical industries. In this study, a recombinant SPase from the Thermobacillus sp. ZCTH02-B1 (rTSPase), which was previously reported to have high thermostability and the catalytic ability to synthesize ascorbic acid 2-glucoside, was attempted to be extracellularly expressed in Escherichia coli BL21(DE3) by fusion of endogenous osmotically-inducible protein Y. Unexpectedly, the rTSPase itself was produced outside the cells with an underestimated performance, although no typical signal peptide was predicted. Further N- and C-terminal truncation experiments revealed that both termini of rTSPase have an important role in protein folding and enzymatic activity, while its secretion was N-terminus associated. Extracellular protein concentration and rTSPase activity achieved 1.8 mg/mL and 6.2 U/mL after induction of 36 h in a 5-L fermenter. High-level extracellular rTSPase production could also be obtained from E. coli within 24 h by inducing overexpression of D, D-carboxypeptidase for cell lysis.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Glucosiltransferases/genética , Paenibacillus/enzimologia , Ácido Ascórbico/análogos & derivados , Ácido Ascórbico/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Técnicas de Cultura Celular por Lotes , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Glucosiltransferases/metabolismo , Glicosilação , Paenibacillus/genética , Engenharia de Proteínas , Proteínas Recombinantes/metabolismo
19.
Int J Biol Macromol ; 173: 379-398, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33484802

RESUMO

Vitamin C (VitC) is a requisite nutrient for humans and other primates. Extensive research continuously illustrates the applications of VitC in promoting cell reprogramming, fine-tuning embryonic stem cell function, and fighting diseases. Given its chemical reduction property, VitC predominantly acts as an antioxidant to reduce reactive oxygen species (ROS) and as a cofactor for certain dioxygenases involved in epigenetic regulation. Here, we propose that VitC is also a bio-signaling molecule based on the finding that sodium-dependent VitC transporter (SVCT) 2 is a novel receptor-like transporter of VitC that possesses dual activities in mediating VitC uptake and Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 2 signaling pathway. Through interaction, SVCT2 induces JAK2 phosphorylation while transporting VitC into cells. Activated JAK2 phosphorylates the C-terminus of SVCT2, resulting in the recruitment and activation of STAT2. As a highlight, our results suggest that the activation of JAK2 synergistically promotes regulation of VitC in ROS scavenging and epigenetic modifications through phosphorylating pyruvate dehydrogenase kinase 1, ten-eleven translocation enzyme 3, and histone H3 Tyr41. Furthermore, VitC-activated JAK2 exhibits bidirectional effects in regulating cell pluripotency and differentiation. Our results thus reveal that the SVCT2-mediated JAK2 activation facilitates VitC functions in a previously unknown manner.


Assuntos
Ácido Ascórbico/metabolismo , Janus Quinase 2/metabolismo , Transportadores de Sódio Acoplados à Vitamina C/genética , Transportadores de Sódio Acoplados à Vitamina C/metabolismo , Animais , Ácido Ascórbico/farmacologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Dioxigenases/genética , Epigênese Genética/efeitos dos fármacos , Células HEK293 , Histonas/metabolismo , Humanos , Camundongos , Células NIH 3T3 , Fosforilação , Domínios Proteicos , Fator de Transcrição STAT2/genética , Transdução de Sinais/efeitos dos fármacos , Transportadores de Sódio Acoplados à Vitamina C/química
20.
Sci Rep ; 11(1): 1770, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33469090

RESUMO

Calcium (Ca) deficiency in cabbage plants induces oxidative damage, hampering growth and decreasing quality, however, it is hypothesized that silicon (Si) added to the nutrient solution may alleviate crop losses. Therefore, this study aims at evaluating whether silicon supplied in the nutrient solution reduces, in fact, the calcium deficiency effects on cabbage plants. In a greenhouse, cabbage plants were grown using nutrient solutions with Ca sufficiency and Ca deficiency (5 mM) without and with added silicon (2.5 mM), arranged as a 2 × 2 factorial in randomized blocks, with five replications. At 91 days after transplanting, the plants were harvested for biological evaluations. In the treatment without added Si, Ca deficiency promoted oxidative stress, low antioxidant content, decreased dry matter, and lower quality leaf. On the other hand, added Si attenuated Ca deficiency in cabbage by decreasing cell extravasation while increasing both ascorbic acid content and fresh and dry matter, providing firmer leaves due to diminished leaf water loss after harvesting. We highlighted the agronomic importance of Si added to the nutrient solution, especially in crops at risk of Ca deficiency.


Assuntos
Ácido Ascórbico/metabolismo , Brassica/crescimento & desenvolvimento , Brassica/metabolismo , Cálcio/deficiência , Silício/metabolismo , Ácido Ascórbico/análise , Estresse Oxidativo/fisiologia , Desenvolvimento Vegetal/fisiologia , Folhas de Planta/crescimento & desenvolvimento , Fenômenos Fisiológicos Vegetais/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
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