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1.
Cell ; 170(6): 1079-1095.e20, 2017 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-28823558

RESUMO

Loss-of-function mutations in TET2 occur frequently in patients with clonal hematopoiesis, myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML) and are associated with a DNA hypermethylation phenotype. To determine the role of TET2 deficiency in leukemia stem cell maintenance, we generated a reversible transgenic RNAi mouse to model restoration of endogenous Tet2 expression. Tet2 restoration reverses aberrant hematopoietic stem and progenitor cell (HSPC) self-renewal in vitro and in vivo. Treatment with vitamin C, a co-factor of Fe2+ and α-KG-dependent dioxygenases, mimics TET2 restoration by enhancing 5-hydroxymethylcytosine formation in Tet2-deficient mouse HSPCs and suppresses human leukemic colony formation and leukemia progression of primary human leukemia PDXs. Vitamin C also drives DNA hypomethylation and expression of a TET2-dependent gene signature in human leukemia cell lines. Furthermore, TET-mediated DNA oxidation induced by vitamin C treatment in leukemia cells enhances their sensitivity to PARP inhibition and could provide a safe and effective combination strategy to selectively target TET deficiency in cancer. PAPERCLIP.


Assuntos
Ácido Ascórbico/farmacologia , Proteínas de Ligação a DNA/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Síndromes Mielodisplásicas/tratamento farmacológico , Proteínas Proto-Oncogênicas/metabolismo , Vitaminas/farmacologia , Animais , Ácido Ascórbico/administração & dosagem , Morte Celular , Linhagem Celular Tumoral , Metilação de DNA , Proteínas de Ligação a DNA/genética , Dioxigenases , Técnicas de Silenciamento de Genes , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Síndromes Mielodisplásicas/genética , Transplante de Neoplasias , Poli(ADP-Ribose) Polimerase-1/genética , Proteínas Proto-Oncogênicas/genética , Transcrição Gênica , Transplante Heterólogo , Vitaminas/administração & dosagem
2.
EMBO J ; 41(4): e106825, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35023164

RESUMO

Despite extensive analysis of pRB phosphorylation in vitro, how this modification influences development and homeostasis in vivo is unclear. Here, we show that homozygous Rb∆K4 and Rb∆K7 knock-in mice, in which either four or all seven phosphorylation sites in the C-terminal region of pRb, respectively, have been abolished by Ser/Thr-to-Ala substitutions, undergo normal embryogenesis and early development, notwithstanding suppressed phosphorylation of additional upstream sites. Whereas Rb∆K4 mice exhibit telomere attrition but no other abnormalities, Rb∆K7 mice are smaller and display additional hallmarks of premature aging including infertility, kyphosis, and diabetes, indicating an accumulative effect of blocking pRb phosphorylation. Diabetes in Rb∆K7 mice is insulin-sensitive and associated with failure of quiescent pancreatic ß-cells to re-enter the cell cycle in response to mitogens, resulting in induction of DNA damage response (DDR), senescence-associated secretory phenotype (SASP), and reduced pancreatic islet mass and circulating insulin level. Pre-treatment with the epigenetic regulator vitamin C reduces DDR, increases cell cycle re-entry, improves islet morphology, and attenuates diabetes. These results have direct implications for cell cycle regulation, CDK-inhibitor therapeutics, diabetes, and longevity.


Assuntos
Envelhecimento/fisiologia , Ácido Ascórbico/farmacologia , Diabetes Mellitus Experimental/prevenção & controle , Proteína do Retinoblastoma/metabolismo , Animais , Senescência Celular/efeitos dos fármacos , Quinase 2 Dependente de Ciclina/antagonistas & inibidores , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Fator de Transcrição E2F1/metabolismo , Desenvolvimento Embrionário/genética , Feminino , Fibroblastos/efeitos dos fármacos , Técnicas de Introdução de Genes , Células Secretoras de Insulina/patologia , Camundongos , Fosforilação , Gravidez , Proteína do Retinoblastoma/genética , Telômero/genética
3.
Immunol Rev ; 305(1): 152-164, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34820863

RESUMO

Micronutrients are essential small molecules required by organisms in minute quantity for survival. For instance, vitamins and minerals, the two major categories of micronutrients, are central for biological processes such as metabolism, cell replication, differentiation, and immune response. Studies estimated that around two billion humans worldwide suffer from micronutrient deficiencies, also known as "hidden hunger," linked to weakened immune responses. While micronutrients affect the immune system at multiple levels, recent studies showed that micronutrients potentially impact the differentiation and function of immune cells as cofactors for epigenetic enzymes, including the 2-oxoglutarate-dependent dioxygenase (2OGDD) family involved in histone and DNA demethylation. Here, we will first provide an overview of the role of DNA methylation in T cells and B cells, followed by the micronutrients ascorbate (vitamin C) and iron, two critical cofactors for 2OGDD. We will discuss the emerging evidence of these micronutrients could regulate adaptive immune response by influencing epigenetic remodeling.


Assuntos
Epigênese Genética , Micronutrientes , Humanos , Imunidade/genética , Micronutrientes/metabolismo , Minerais/metabolismo , Vitaminas
4.
Eur J Immunol ; 54(7): e2451028, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38616772

RESUMO

Vitamin C (ascorbic acid) is a potent antioxidant and a cofactor for various enzymes including histone demethylases and methylcytosine dioxygenases. Vitamin C also exerts direct cytotoxicity toward selected tumor cells including colorectal carcinoma. Moreover, vitamin C has been shown to impact immune cell differentiation at various levels including maturation and/or functionality of T cells and their progenitors, dendritic cells, B cells, and NK cells. γδ T cells have recently attracted great interest as effector cells for cell-based cancer immunotherapy, due to their HLA-independent recognition of a large variety of tumor cells. While γδ T cells can thus be also applied as an allogeneic off-the-shelf product, it is obvious that the effector function of γδ T cells needs to be optimized to ensure the best possible clinical efficacy. Here we review the immunomodulatory mechanisms of vitamin C with a special focus on how vitamin C enhances the effector function of γδ T cells. We also discuss future directions of how vitamin C can be used in the clinical setting to boost the efficacy of adoptive cell therapies.


Assuntos
Ácido Ascórbico , Receptores de Antígenos de Linfócitos T gama-delta , Ácido Ascórbico/farmacologia , Humanos , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Animais , Imunoterapia Adotiva/métodos , Linfócitos T/imunologia , Neoplasias/imunologia , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Diferenciação Celular/imunologia , Diferenciação Celular/efeitos dos fármacos
5.
EMBO Rep ; 24(4): e56374, 2023 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-36876523

RESUMO

ACE2 is a major receptor for cellular entry of SARS-CoV-2. Despite advances in targeting ACE2 to inhibit SARS-CoV-2 binding, strategies to flexibly and sufficiently reduce ACE2 levels for the prevention of SARS-CoV-2 infection have not been explored. Here, we reveal vitamin C (VitC) administration as a potent strategy to prevent SARS-CoV-2 infection. VitC reduces ACE2 protein levels in a dose-dependent manner, while even a partial reduction in ACE2 levels can greatly inhibit SARS-CoV-2 infection. Further studies reveal that USP50 is a crucial regulator of ACE2 levels. VitC blocks the USP50-ACE2 interaction, thus promoting K48-linked polyubiquitination of ACE2 at Lys788 and subsequent degradation of ACE2 without affecting its transcriptional expression. Importantly, VitC administration reduces host ACE2 levels and greatly blocks SARS-CoV-2 infection in mice. This study reveals that ACE2 protein levels are down-regulated by an essential nutrient, VitC, thereby enhancing protection against infection of SARS-CoV-2 and its variants.


Assuntos
COVID-19 , Animais , Camundongos , SARS-CoV-2 , Enzima de Conversão de Angiotensina 2 , Ácido Ascórbico/farmacologia
6.
EMBO Rep ; 24(6): e56319, 2023 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-37114473

RESUMO

Vitamins are essential micronutrients, but the mechanisms of vitamin chemoreception in animals are poorly understood. Here, we provide evidence that vitamin C doubles starvation resistance and induces egg laying in Drosophila melanogaster. Our behavioral analyses of genetically engineered and anatomically ablated flies show that fruit flies sense vitamin C via sweet-sensing gustatory receptor neurons (GRNs) in the labellum. Using a behavioral screen and in vivo electrophysiological analyses of ionotropic receptors (IRs) and sweet-sensing gustatory receptors (GRs), we find that two broadly tuned IRs (i.e., IR25a and IR76b) and five GRs (i.e., GR5a, GR61a, GR64b, GR64c, and GR64e) are essential for vitamin C detection. Thus, vitamin C is directly detected by the fly labellum and requires at least two distinct receptor types. Next, we expand our electrophysiological study to test attractive tastants such as sugars, carboxylic acids, and glycerol. Our analysis elucidates the molecular basis of chemoreception in sweet-sensing GRNs.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Drosophila/fisiologia , Drosophila melanogaster/genética , Paladar/fisiologia , Ácido Ascórbico/farmacologia , Proteínas de Drosophila/genética , Vitaminas , Receptores de Superfície Celular/genética
7.
J Biol Chem ; 299(8): 104976, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37390985

RESUMO

Urate transporters play a pivotal role in urate handling in the human body, but the urate transporters identified to date do not account for all known molecular processes of urate handling, suggesting the presence of latent machineries. We recently showed that a urate transporter SLC2A12 is also a physiologically important exporter of ascorbate (the main form of vitamin C in the body) that would cooperate with an ascorbate importer, sodium-dependent vitamin C transporter 2 (SVCT2). Based on the dual functions of SLC2A12 and cooperativity between SLC2A12 and SVCT2, we hypothesized that SVCT2 might be able to transport urate. To test this proposal, we conducted cell-based analyses using SVCT2-expressing mammalian cells. The results demonstrated that SVCT2 is a novel urate transporter. Vitamin C inhibited SVCT2-mediated urate transport with a half-maximal inhibitory concentration of 36.59 µM, suggesting that the urate transport activity may be sensitive to physiological ascorbate levels in blood. Similar results were obtained for mouse Svct2. Further, using SVCT2 as a sodium-dependent urate importer, we established a cell-based urate efflux assay that will be useful for identification of other novel urate exporters as well as functional characterization of nonsynonymous variants of already-identified urate exporters including ATP-binding cassette transporter G2. While more studies will be needed to elucidate the physiological impact of SVCT2-mediated urate transport, our findings deepen understanding of urate transport machineries.


Assuntos
Transportadores de Ânions Orgânicos Dependentes de Sódio , Transportadores de Sódio Acoplados à Vitamina C , Ácido Úrico , Animais , Humanos , Camundongos , Ácido Ascórbico/metabolismo , Transportadores de Ânions Orgânicos Dependentes de Sódio/genética , Transportadores de Ânions Orgânicos Dependentes de Sódio/metabolismo , Transportadores de Sódio Acoplados à Vitamina C/genética , Ácido Úrico/metabolismo
8.
Glia ; 72(4): 708-727, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38180226

RESUMO

Radial glia (RG) cells generate neurons and glial cells that make up the cerebral cortex. Both in rodents and humans, these stem cells remain for a specific time after birth, named late radial glia (lRG). The knowledge of lRG and molecules that may be involved in their differentiation is based on very limited data. We analyzed whether ascorbic acid (AA) and its transporter SVCT2, are involved in lRG cells differentiation. We demonstrated that lRG cells are highly present between the first and fourth postnatal days. Anatomical characterization of lRG cells, revealed that lRG cells maintained their bipolar morphology and stem-like character. When lRG cells were labeled with adenovirus-eGFP at 1 postnatal day, we detected that some cells display an obvious migratory neuronal phenotype, suggesting that lRG cells continue generating neurons postnatally. Moreover, we demonstrated that SVCT2 was apically polarized in lRG cells. In vitro studies using the transgenic mice SVCT2+/- and SVCT2tg (SVCT2-overexpressing mouse), showed that decreased SVCT2 levels led to accelerated differentiation into astrocytes, whereas both AA treatment and elevated SVCT2 expression maintain the lRG cells in an undifferentiated state. In vivo overexpression of SVCT2 in lRG cells generated cells with a rounded morphology that were migratory and positive for proliferation and neuronal markers. We also examined mediators that can be involved in AA/SVCT2-modulated signaling pathways, determining that GSK3-ß through AKT, mTORC2, and PDK1 is active in brains with high levels of SVCT2/AA. Our data provide new insights into the role of AA and SVCT2 in late RG cells.


Assuntos
Ácido Ascórbico , Transportadores de Sódio Acoplados à Vitamina C , Animais , Humanos , Camundongos , Ácido Ascórbico/farmacologia , Células Ependimogliais/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Camundongos Transgênicos , Neurônios/metabolismo , Transportadores de Sódio Acoplados à Vitamina C/genética
9.
J Neurochem ; 168(2): 142-160, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38169121

RESUMO

White matter injury (WMI) is one of the most serious complications associated with preterm births. Damage to oligodendrocytes, which are the key cells involved in WMI pathogenesis, can directly lead to myelin abnormalities. L-ascorbyl-2-phosphate (AS-2P) is a stable form of vitamin C. This study aimed to explore the protective effects of AS-2P against chronic hypoxia-induced WMI, and elucidate the underlying mechanisms. An in vivo chronic hypoxia model and in vitro oxygen-glucose deprivation (OGD) model were established to explore the effects of AS-2P on WMI using immunofluorescence, immunohistochemistry, western blotting, real-time quantitative polymerase chain reaction, Morris water maze test, novel object recognition test, beaming-walking test, electron microscopy, and flow cytometry. The results showed that AS-2P resulted in the increased expression of MBP, Olig2, PDGFRα and CC1, improved thickness and density of the myelin sheath, and reduced TNF-α expression and microglial cell infiltration to alleviate inflammation in the brain after chronic hypoxia. Moreover, AS-2P improved the memory, learning and motor abilities of the mice with WMI. These protective effects of AS-2P may involve the upregulation of protein arginine methyltransferase 5 (PRMT5) and downregulation of P53 and NF-κB. In conclusion, our study demonstrated that AS-2P attenuated chronic hypoxia-induced WMI in vivo and OGD-induced oligodendrocyte injury in vitro possibly by regulating the PRMT5/P53/NF-κB pathway, suggesting that AS-2P may be a potential therapeutic option for WMI.


Assuntos
Lesões Encefálicas , Substância Branca , Animais , Camundongos , NF-kappa B/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais Recém-Nascidos , Substância Branca/patologia , Hipóxia/metabolismo , Lesões Encefálicas/patologia , Ácido Ascórbico/metabolismo , Oxigênio/metabolismo
10.
Funct Integr Genomics ; 24(2): 73, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38598147

RESUMO

Vitamin C, also known as ascorbic acid, is an essential nutrient that plays a critical role in many physiological processes in plants and animals. In humans, vitamin C is an antioxidant, reducing agent, and cofactor in diverse chemical processes. The established role of vitamin C as an antioxidant in plants is well recognized. It neutralizes reactive oxygen species (ROS) that can cause damage to cells. Also, it plays an important role in recycling other antioxidants, such as vitamin E, which helps maintain the overall balance of the plant's antioxidant system. However, unlike plants, humans cannot synthesize ascorbic acid or vitamin C in their bodies due to the absence of an enzyme called gulonolactone oxidase. This is why humans need to obtain vitamin C through their diet. Different fruits and vegetables contain varying levels of vitamin C. The biosynthesis of vitamin C in plants occurs primarily in the chloroplasts and the endoplasmic reticulum (ER). The biosynthesis of vitamin C is a complex process regulated by various factors such as light, temperature, and plant hormones. Recent research has identified several key genes that regulate vitamin C biosynthesis, including the GLDH and GLDH genes. The expression of these genes is known to be regulated by various factors such as light, temperature, and plant hormones. Recent studies highlight vitamin C's crucial role in regulating plant stress response pathways, encompassing drought, high salinity, and oxidative stress. The key enzymes in vitamin C biosynthesis are L-galactose dehydrogenase (GLDH) and L-galactono-1, 4-lactone dehydrogenase (GLDH). Genetic studies reveal key genes like GLDH and GLDH in Vitamin C biosynthesis, offering potential for crop improvement. Genetic variations influence nutritional content through their impact on vitamin C levels. Investigating the roles of genes in stress responses provides insights for developing resilient techniques in crop growth. Some fruits and vegetables, such as oranges, lemons, and grapefruits, along with strawberries and kiwi, are rich in vitamin C. Guava. Papaya provides a boost of vitamin C and dietary fiber. At the same time, red and yellow bell peppers, broccoli, pineapple, mangoes, and kale are additional sources of this essential nutrient, promoting overall health. In this review, we will discuss a brief history of Vitamin C and its signaling and biosynthesis pathway and summarize the regulation of its content in various fruits and vegetables.


Assuntos
Ácido Ascórbico , Verduras , Animais , Humanos , Antioxidantes , Frutas/genética , Reguladores de Crescimento de Plantas , Produtos Agrícolas/genética , Transdução de Sinais
11.
J Mol Evol ; 92(3): 266-277, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38683367

RESUMO

Ascorbic acid functions as an antioxidant and facilitates other biochemical processes such as collagen triple helix formation, and iron uptake by cells. Animals which endogenously produce ascorbic acid have a functional gulonolactone oxidase gene (GULO); however, humans have a GULO pseudogene (GULOP) and depend on dietary ascorbic acid. In this study, the conservation of GULOP sequences in the primate haplorhini suborder were investigated and compared to the GULO sequences belonging to the primates strepsirrhini suborder. Phylogenetic analysis suggested that the conserved GULOP exons in the haplorhini primates experienced a high rate of mutations following the haplorhini/strepsirrhini divergence. This high mutation rate has decreased during the evolution of the haplorhini primates. Additionally, indels of the haplorhini GULOP sequences were conserved across the suborder. A separate analysis for GULO sequences and well-conserved GULOP sequences focusing on placental mammals identified an in-frame GULO sequence in the Brazilian guinea pig, and a potential GULOP sequence in the pika. Similar to haplorhini primates, the guinea pig and lagomorph species have experienced a high substitution rate when compared to the mammals used in this study. A shared synteny to examine the conservation of local genes near GULO/GULOP identified a conserved inversion around the GULO/GULOP locus between the haplorhini and strepsirrhini primates. Fischer's exact test did not support an association between GULOP and the chromosomal inversion. Mauve alignment showed that the inversion of the length of the syntenic block that the GULO/GULOP genes belonged to was variable. However, there were frequent rearrangements around ~ 2 million base pairs adjacent to GULOP involving the KIF13B and MSRA genes. These data may suggest that genes acquiring deleterious mutations in the coding sequence may respond to these deleterious mutations with rapid substitution rates.


Assuntos
Inversão Cromossômica , Evolução Molecular , Éxons , L-Gulonolactona Oxidase , Mutação , Filogenia , Primatas , Animais , Éxons/genética , Primatas/genética , Mutação/genética , Humanos , L-Gulonolactona Oxidase/genética , Inversão Cromossômica/genética , Pseudogenes/genética , Sequência Conservada/genética
12.
Biochem Biophys Res Commun ; 695: 149463, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38176172

RESUMO

Cisplatin-induced acute kidney injury (AKI) restricts the use of cisplatin as a first-line chemotherapeutic agent. Our previous study showed that prophylactic vitamin C supplementation may act as an epigenetic modulator in alleviating cisplatin-induced AKI in mice. However, the targets of vitamin C and the mechanisms underlying the epigenetics changes remain largely unknown. Herein, whole-genome bisulfite sequencing and bulk RNA sequencing were performed on the kidney tissues of mice treated with cisplatin with prophylactic vitamin C supplementation (treatment mice) or phosphate-buffered saline (control mice) at 24 h after cisplatin treatment. Ascorbyl phosphate magnesium (APM), an oxidation-resistant vitamin C derivative, was found that led to global hypomethylation in the kidney tissue and regulated different functional genes in the promoter region and gene body region. Integrated evidence suggested that APM enhanced renal ion transport and metabolism, and reduced apoptosis and inflammation in the kidney tissues. Strikingly, Mapk15, Slc22a6, Cxcl5, and Cd44 were the potential targets of APM that conferred protection against cisplatin-induced AKI. Moreover, APM was found to be difficult to rescue cell proliferation and apoptosis caused by cisplatin in the Slc22a6 knockdown cell line. These results elucidate the mechanism by which vitamin C as an epigenetic regulator to protects against cisplatin-induced AKI and provides a new perspective and evidence support for controlling the disease process through regulating DNA methylation.


Assuntos
Injúria Renal Aguda , Antineoplásicos , Camundongos , Animais , Cisplatino/efeitos adversos , Antineoplásicos/farmacologia , Desmetilação do DNA , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/genética , Injúria Renal Aguda/prevenção & controle , Rim/metabolismo , Apoptose , Magnésio/metabolismo , Vitaminas/farmacologia , Suplementos Nutricionais , Ácido Ascórbico/metabolismo , Fosfatos/metabolismo , Camundongos Endogâmicos C57BL
13.
BMC Plant Biol ; 24(1): 149, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38418950

RESUMO

BACKGROUND: Consecutive droughts and quantitative and qualitative reduction of surface and underground water resources have caused an increase in greenhouse and hydroponic cultivation for most garden crops, including strawberries, in Iran. On the other hand, most of the inputs of greenhouse crops in Iran are imported. To possibility of replacing vermicompost with peat moss under hydroponic cultivation, an experiment was done in a split plot based on randomized complete blocks design in three replications in Isfahan (Iran) Agricultural and Natural Resources Research Center in 2019. The main treatment was substrate at four levels included different levels of vermicompost (30 and 50%) and peat moss (30 and 50%) in combination with perlite and sub-treatment were Selva and Camarosa cultivars. RESULTS: The results showed that Camarosa cultivar and Selva cultivar in (perlite/ peat moss 50:50) and Selva cultivar in (perlite / vermicompost 70:30) had maximum yield. Leaf number and chlorophyll index were maximum in Camarosa cultivar in peat moss substrates. Strawberry cultivars had the highest root fresh weight, the content of vitamin C and total soluble solids (TSS) in substrates containing vermicompost. Camarosa cultivar in (perlite / peat moss50:50) and Selva cultivar in (perlite /vermicompost 50:50) had maximum root dry weight. Also, the highest number of inflorescences was related to substrates containing peat moss and (perlite /vermicompost 70:30). Maximum amount of fresh and dry weight of shoots were observed in (perlite/ peat moss70:30). Selva cultivar had more inflorescences (16.5%) than Camarosa cultivar and Camarosa cultivar produced more fresh and dry weight of shoots (16.5%, 23.01%) than Selva cultivar. CONCLUSION: Expriment results highlighted the importance of considering both main and sub-treatments in agricultural research, as they interacted to influence various growth and yield parameters. 50% vermicompost treatment combined with perlite had a positive impact on plant growth and in quality index such as vitamin C content and TSS was highest. while the choice of cultivar affected different aspects of plant development. Selva cultivar was known to be more tolerant to salinity caused by vermicompost. Vermicompost is local and more economical, also salt resistant cultivars are recommended in a controlled (30%) amount of vermicompost.


Assuntos
Óxido de Alumínio , Fragaria , Dióxido de Silício , Sphagnopsida , Solo , Ácido Ascórbico
14.
BMC Microbiol ; 24(1): 30, 2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38245680

RESUMO

BACKGROUND: Macrolide antibiotics have been extensively used for the treatment of Staphylococcus aureus infections. However, the emergence of macrolide-resistant strains of S. aureus has become a major concern for public health. The molecular mechanisms underlying macrolide resistance in S. aureus are complex and diverse, involving both target site modification and efflux pump systems. In this study, we aim to overcome the molecular diversity of macrolide resistance mechanisms in S. aureus by identifying common molecular targets that could be exploited for the development of novel therapeutics. METHODS: About 300 Staphylococcus aureus different isolates were recovered and purified from 921 clinical specimen including urine (88), blood (156), sputum (264), nasal swabs (168), pus (181) and bone (39) collected from different departments in Tanta University Hospital. Macrolide resistant isolates were detected and tested for Multi Drug Resistant (MDR). Gel electrophoresis was performed after the D test and PCR reaction for erm(A), (B), (C), msr(A), and mph(C) genes. Finally, we tried different combinations of Erythromycin or Azithromycin antibiotics with either vitamin K3 or vitamin C. RESULTS: Macrolide resistance S. aureus isolates exhibited 7 major resistance patterns according to number of resistance markers and each pattern included sub patterns or subgroups. The PCR amplified products of different erm genes; analysis recorded different phenotypes of the Staphylococcus aureus isolates according to their different genotypes. In addition, our new tested combinations of Erythromycin and vitamin C, Erythromycin, and vitamin K3, Azithromycin and vitamin C and Azithromycin and vitamin K3 showed significant antibacterial effect when using every antibiotic alone. Our findings provide new insights into the molecular mechanisms of macrolide resistance in S. aureus and offer potential strategies for the development of novel protocols to overcome this emerging public health threat.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Antibacterianos/farmacologia , Staphylococcus aureus , Macrolídeos/farmacologia , Vitaminas/farmacologia , Lincosamidas/farmacologia , Azitromicina/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Farmacorresistência Bacteriana/genética , Estreptogramina B/farmacologia , Eritromicina/farmacologia , Infecções Estafilocócicas/microbiologia , Vitamina K/farmacologia , Vitamina A/farmacologia , Testes de Sensibilidade Microbiana , Ácido Ascórbico/farmacologia , Variação Genética
15.
J Exp Bot ; 75(9): 2631-2643, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38349339

RESUMO

Ascorbate is involved in numerous vital processes, in particular in response to abiotic but also biotic stresses whose frequency and amplitude increase with climate change. Ascorbate levels vary greatly depending on species, tissues, or stages of development, but also in response to stress. Since its discovery, the ascorbate biosynthetic pathway has been intensely studied and it appears that GDP-l-galactose phosphorylase (GGP) is the enzyme with the greatest role in the control of ascorbate biosynthesis. Like other enzymes of this pathway, its expression is induced by various environmental and also developmental factors. Although mRNAs encoding it are among the most abundant in the transcriptome, the protein is only present in very small quantities. In fact, GGP translation is repressed by a negative feedback mechanism involving a small open reading frame located upstream of the coding sequence (uORF). Moreover, its activity is inhibited by a PAS/LOV type photoreceptor, the action of which is counteracted by blue light. Consequently, this multi-level regulation of GGP would allow fine control of ascorbate synthesis. Indeed, experiments varying the expression of GGP have shown that it plays a central role in response to stress. This new understanding will be useful for developing varieties adapted to future environmental conditions.


Assuntos
Ácido Ascórbico , Monoéster Fosfórico Hidrolases , Ácido Ascórbico/biossíntese , Ácido Ascórbico/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética
16.
J Exp Bot ; 75(9): 2604-2630, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38300237

RESUMO

Ascorbate (vitamin C) is one of the most abundant primary metabolites in plants. Its complex chemistry enables it to function as an antioxidant, as a free radical scavenger, and as a reductant for iron and copper. Ascorbate biosynthesis occurs via the mannose/l-galactose pathway in green plants, and the evidence for this pathway being the major route is reviewed. Ascorbate accumulation is leaves is responsive to light, reflecting various roles in photoprotection. GDP-l-galactose phosphorylase (GGP) is the first dedicated step in the pathway and is important in controlling ascorbate synthesis. Its expression is determined by a combination of transcription and translation. Translation is controlled by an upstream open reading frame (uORF) which blocks translation of the main GGP-coding sequence, possibly in an ascorbate-dependent manner. GGP associates with a PAS-LOV protein, inhibiting its activity, and dissociation is induced by blue light. While low ascorbate mutants are susceptible to oxidative stress, they grow nearly normally. In contrast, mutants lacking ascorbate do not grow unless rescued by supplementation. Further research should investigate possible basal functions of ascorbate in severely deficient plants involving prevention of iron overoxidation in 2-oxoglutarate-dependent dioxygenases and iron mobilization during seed development and germination.


Assuntos
Ácido Ascórbico , Plantas , Ácido Ascórbico/metabolismo , Ácido Ascórbico/biossíntese , Plantas/metabolismo , Plantas/genética , Regulação da Expressão Gênica de Plantas , Vias Biossintéticas
17.
J Exp Bot ; 75(9): 2754-2771, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38224521

RESUMO

l-Ascorbic acid (AsA, vitamin C) is a pivotal dietary nutrient with multifaceted importance in living organisms. In plants, the Smirnoff-Wheeler pathway is the primary route for AsA biosynthesis, and understanding the mechanistic details behind its component enzymes has implications for plant biology, nutritional science, and biotechnology. As part of an initiative to determine the structures of all six core enzymes of the pathway, the present study focuses on three of them in the model species Myrciaria dubia (camu-camu): GDP-d-mannose 3',5'-epimerase (GME), l-galactose dehydrogenase (l-GalDH), and l-galactono-1,4-lactone dehydrogenase (l-GalLDH). We provide insights into substrate and cofactor binding and the conformational changes they induce. The MdGME structure reveals a distorted substrate in the active site, pertinent to the catalytic mechanism. Mdl-GalDH shows that the way in which NAD+ association affects loop structure over the active site is not conserved when compared with its homologue in spinach. Finally, the structure of Mdl-GalLDH is described for the first time. This allows for the rationalization of previously identified residues which play important roles in the active site or in the formation of the covalent bond with FAD. In conclusion, this study enhances our understanding of AsA biosynthesis in plants, and the information provided should prove useful for biotechnological applications.


Assuntos
Ácido Ascórbico , Frutas , Myrtaceae , Proteínas de Plantas , Ácido Ascórbico/metabolismo , Ácido Ascórbico/biossíntese , Frutas/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/química , Myrtaceae/metabolismo , Myrtaceae/genética , Galactose Desidrogenases/metabolismo , Galactose Desidrogenases/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/genética
18.
Toxicol Appl Pharmacol ; 482: 116798, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38160894

RESUMO

Osteosarcoma (OS) is a common malignant tumor disease in the department of orthopedics, which is prone to the age of adolescents and children under 20 years old. Arsenic trioxide (ATO), an ancient poison, has been reported to play a critical role in a variety of tumor treatments, including OS. However, due to certain poisonous side effects such as cardiotoxicity and hepatotoxicity, clinical application of ATO has been greatly limited. Here we report that low doses of ATO (1 µM) observably reduced the half-effective inhibitory concentration (IC50) of vitamin C on OS cells. Compared with the treatment alone, the synthetic application of vitamin C (VitC, 800 µM) and ATO (1 µM) significantly further inhibited the proliferation, migration, and invasion of OS cells and promoted cell apoptosis in vitro. Meanwhile, we observed that the combined application of VitC and ATO directly suppresses the aerobic glycolysis of OS cells with the decreased production of pyruvate, lactate, and ATP via inhibiting the expression of the critical glycolytic genes (PGK1, PGM1, and LDHA). Moreover, the combination of VitC (200 mg/kg) and ATO (1 mg/kg) with tail vein injection significantly delayed OS growth and migration of nude mice by inhibiting aerobic glycolysis of OS. Thus, our results demonstrate that VitC effectively increases the sensitivity of OS to low concentrations of ATO via inhibiting aerobic glycolysis to alleviate the toxic side effects of high doses of arsenic trioxide, suggesting that synthetic application of VitC and ATO is a promising approach for the clinical treatment of human OS.


Assuntos
Arsenicais , Neoplasias Ósseas , Osteossarcoma , Animais , Camundongos , Criança , Humanos , Adolescente , Adulto Jovem , Adulto , Trióxido de Arsênio/farmacologia , Ácido Ascórbico/farmacologia , Camundongos Nus , Óxidos/toxicidade , Arsenicais/farmacologia , Apoptose , Osteossarcoma/tratamento farmacológico , Vitaminas/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Glicólise , Linhagem Celular Tumoral
19.
Allergy ; 79(2): 353-383, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38084827

RESUMO

Nutritional Immunity is one of the most ancient innate immune responses, during which the body can restrict nutrients availability to pathogens and restricts their uptake by the gut mucosa (mucosal block). Though this can be a beneficial strategy during infection, it also is associated with non-communicable diseases-where the pathogen is missing; leading to increased morbidity and mortality as micronutritional uptake and distribution in the body is hindered. Here, we discuss the acute immune response in respect to nutrients, the opposing nutritional demands of regulatory and inflammatory cells and particularly focus on some nutrients linked with inflammation such as iron, vitamins A, Bs, C, and other antioxidants. We propose that while the absorption of certain micronutrients is hindered during inflammation, the dietary lymph path remains available. As such, several clinical trials investigated the role of the lymphatic system during protein absorption, following a ketogenic diet and an increased intake of antioxidants, vitamins, and minerals, in reducing inflammation and ameliorating disease.


Assuntos
Micronutrientes , Vitaminas , Humanos , Micronutrientes/uso terapêutico , Vitaminas/uso terapêutico , Antioxidantes/metabolismo , Vitamina A , Inflamação/tratamento farmacológico , Mucosa/metabolismo
20.
Anal Biochem ; 692: 115574, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38782251

RESUMO

Ascorbic acid (AA), a prominent antioxidant commonly found in human blood serum, serves as a biomarker for assessing oxidative stress levels. Therefore, precise detection of AA is crucial for swiftly diagnosing conditions arising from abnormal AA levels. Consequently, the primary aim of this research is to develop a sensitive and selective electrochemical sensor for accurate AA determination. To accomplish this aim, we used a novel nanocomposite comprised of CeO2-doped ZnO adorned on biomass-derived carbon (CeO2·ZnO@BC) as the active nanomaterial, effectively fabricating a glassy carbon electrode (GCE). Various analytical techniques were employed to scrutinize the structure and morphology features of the CeO2·ZnO@BC nanocomposite, ensuring its suitability as the sensing nanomaterial. This innovative sensor is capable of quantifying a wide range of AA concentrations, spanning from 0.5 to 1925 µM in a neutral phosphate buffer solution. It exhibits a remarkable sensitivity of 0.2267 µA µM-1cm-2 and a practical detection limit of 0.022 µM. Thanks to its exceptional sensitivity and selectivity, this sensor enables highly accurate determination of AA concentrations in real samples. Moreover, its superior reproducibility, repeatability, and stability underscore its reliability and robustness for AA quantification.


Assuntos
Ácido Ascórbico , Carbono , Cério , Técnicas Eletroquímicas , Nanocompostos , Óxido de Zinco , Ácido Ascórbico/análise , Ácido Ascórbico/química , Ácido Ascórbico/sangue , Nanocompostos/química , Óxido de Zinco/química , Técnicas Eletroquímicas/métodos , Cério/química , Carbono/química , Humanos , Biomassa , Eletrodos , Limite de Detecção
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