Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 861
Filtrar
1.
Int J Mol Sci ; 22(2)2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33435615

RESUMO

Celiac disease is an autoimmune disorder characterized by a heightened immune response to gluten proteins in the diet, leading to gastrointestinal symptoms and mucosal damage localized to the small intestine. Despite its prevalence, the only treatment currently available for celiac disease is complete avoidance of gluten proteins in the diet. Ongoing clinical trials have focused on targeting the immune response or gluten proteins through methods such as immunosuppression, enhanced protein degradation and protein sequestration. Recent studies suggest that polyphenols may elicit protective effects within the celiac disease milieu by disrupting the enzymatic hydrolysis of gluten proteins, sequestering gluten proteins from recognition by critical receptors in pathogenesis and exerting anti-inflammatory effects on the system as a whole. This review highlights mechanisms by which polyphenols can protect against celiac disease, takes a critical look at recent works and outlines future applications for this potential treatment method.


Assuntos
Doenças Autoimunes/imunologia , Doença Celíaca/imunologia , Gliadina/imunologia , Polifenóis/imunologia , Doenças Autoimunes/metabolismo , Doenças Autoimunes/prevenção & controle , Doença Celíaca/metabolismo , Doença Celíaca/prevenção & controle , Gliadina/metabolismo , Glutens/imunologia , Glutens/metabolismo , Humanos , Imunossupressão/métodos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/imunologia , Intestino Delgado/metabolismo , Polifenóis/metabolismo , Polifenóis/uso terapêutico , Estudos Prospectivos
2.
Food Chem ; 346: 128903, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33429299

RESUMO

Phosvitin (PSV) is considered as a good emulsifier, although it has a low proportion of hydrophobic regions and steric hindrance. Wheat gluten (WG) possesses excellent hydrophobicity and macromolecular network structure. In this work, WG was subjected to a series of Na2SO3 solution, followed by cross-linking with PSV under transglutaminase (TGase) catalyzation. The results showed that Na2SO3 could break disulfide bonds of WG and increase its solubility from 7.33% to 42.82% with 1200 mg/L of Na2SO3. Correspondingly, the cross-linking degree was significantly enhanced. Compared to PSV, the cross-linked PSV-WG exhibited a higher surface hydrophobicity and thermal stability, with a lower zeta potential and apparent viscosity. The emulsifying activity of PSV-WG reached 17.42, 20.63 and 20.28 m2/g with Na2SO3 concentration of 300, 600 and 900 mg/L, which were all higher than that of PSV (15.19 m2/g). This work provided a novel strategy to elevate emulsifying properties of PSV by cross-link reaction.


Assuntos
Glutens/metabolismo , Fosvitina/metabolismo , Sulfatos/química , Transglutaminases/metabolismo , Biocatálise , Dissulfetos/química , Emulsificantes/química , Glutens/química , Interações Hidrofóbicas e Hidrofílicas , Peso Molecular , Fosvitina/química , Solubilidade , Temperatura , Triticum/metabolismo , Viscosidade
3.
Food Chem ; 335: 127663, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32738540

RESUMO

Dissecting the functions of high molecular weight glutenin subunits (HMW-GSs) is helpful for improving wheat quality via breeding. In this study, we used a wheat mutant AS273 in which HMW-GS 1Dy12 was silenced to investigate the silencing mechanism of 1Dy12 and its effects on gluten accumulation and flour-processing quality. Results suggested that the expression of 1Dy12 in AS273 was decreased by one fifth during grain development; a stop codon produced by a base mutation (C/T) led to truncated translation; the absence of 1Dy12 stimulated the accumulation of low molecular weight glutenin subunits (LMW-GSs), gliadins, and glutenin macropolymers, and was resulted in larger protein bodies; AS273 had an inferior flour-processing performance. Based on the outputs achieved in this study it is concluded that 1Dy12 makes important contributions to bread, sponge cake and biscuit-processing quality.


Assuntos
Pão , Glutens/genética , Glutens/metabolismo , Triticum/genética , Triticum/metabolismo , Pão/análise , Códon de Terminação , Eletroforese em Gel de Poliacrilamida , Farinha , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Gliadina/metabolismo , Peso Molecular , Mutação , Proteínas de Armazenamento de Sementes/genética , Proteínas de Armazenamento de Sementes/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Triticum/crescimento & desenvolvimento
4.
PLoS One ; 15(8): e0237711, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810182

RESUMO

Alleles at the Glu-1 loci play important roles in the functional properties of wheat flour. The effects of various high-molecular-weight glutenin subunit (HMW-GS) compositions on quality traits and bread-making properties were evaluated using 235 doubled haploid lines (DHs). The experiment was conducted in a split plot design with two water regimes as the main plot treatment, and DH lines as the subplot treatments. Results showed that the presence of subunit pair 5+10 at the Glu-D1 locus, either alone or in combination with others, appears to provide an improvement in quality and bread-making properties. At the Glu-A1 locus, subunit 1 produced a higher Zeleny sedimentation value (Zel) and stretch area (SA) than subunit 2* when subunits 14+15 and 5+10 were expressed at the Glu-B1 and Glu-D1 loci, and 2* had a positive effect on the maximum dough resistance (Rmax) when subunits 14+15 and 5'+12 were expressed at the Glu-B1 and Glu-D1 loci, respectively. Given subunit 1 at the Glu-A1 locus and 5'+12 at the Glu-D1 locus, the effects of Glu-B1 subunits 14+15 on the tractility (Tra), dough stability time (ST), and dough development time (DT) under the well-watered regime were significantly higher than those of Glu-B1 subunits 13+16. However, 13+16 had a positive effect on SA under the rain-fed regime when subunits 2* and 5+10 were expressed at the Glu-A1 and Glu-D1 loci, respectively. Multiple comparisons analysis revealed that the Zel and Rmax of the six subunits and eight HMW-GS compositions were stable under different water regimes. Overall, subunit compositions 1, 13+16 and 5+10 and 1, 14+15 and 5+10 had higher values for quality traits and bread-baking properties under the two water regimes. These results could play a positive guiding role in selecting and popularizing varieties suitable for production and cultivation in local areas.


Assuntos
Qualidade dos Alimentos , Glutens/genética , Melhoramento Vegetal , Subunidades Proteicas/genética , Triticum/química , Irrigação Agrícola/métodos , Pão/normas , China , Farinha/normas , Genes de Plantas/genética , Loci Gênicos , Glutens/metabolismo , Haploidia , Peso Molecular , Subunidades Proteicas/química , Triticum/genética , Triticum/crescimento & desenvolvimento
5.
PLoS One ; 15(8): e0238283, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857796

RESUMO

AIMS: Non-Coeliac Gluten Sensitivity (NCGS) is poorly understood, particularly in terms of its neurological outcomes. We initially conducted a prospective postal survey to investigate its neurological presentation and symptom course. Results from this then motivated a follow-up pilot study utilising brain MRI to characterise potential diagnostic biomarkers for future research. METHODS: Patients with NCGS were recruited from a specialist centre and completed a prospective postal questionnaire (N = 125). This summarised symptoms experienced, their severity and their course. Onset time was compared by Chi-squared analysis to data from the same centre concerning coeliac disease patients (N = 224). Five respondents on a strict gluten-free diet who self-reported brain fog then attended a pilot study, completing MR brain imaging/questionnaires before/after a gluten challenge. "Baseline" data were assessed for abnormalities, while symptom severity and cerebral blood flow (CBF) were compared before/after challenge. RESULTS: Survey participants were aged 47 (85% female). Prevalence of neurological symptoms were: headaches (51%), brain fog (48%), balance issues (31%), tingling (19%). Median symptom resolution time was 48 hours, while onset was 90 minutes; onset pattern was not significantly different compared to CD patients (p = 0.322). Extra-intestinal symptoms worsened by 37%(±28) during a typical reaction. Predominantly non-statistical observations from the brain imaging study are discussed. CONCLUSIONS: Neurological symptoms in NCGS are common, and onset time is comparable to that in CD. Brain imaging may be a useful future means of investigating physiological injury and responses to gluten in further study.


Assuntos
Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Imagem por Ressonância Magnética , Síndromes de Malabsorção/diagnóstico por imagem , Adolescente , Adulto , Idoso , Disfunção Cognitiva/etiologia , Dieta Livre de Glúten , Feminino , Seguimentos , Glutens/metabolismo , Humanos , Síndromes de Malabsorção/dietoterapia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudo de Prova de Conceito , Estudos Prospectivos , Autorrelato , Índice de Gravidade de Doença , Adulto Jovem
6.
Food Chem ; 332: 127422, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32623129

RESUMO

During wheat cultivation, glyphosate-based herbicides are recommended to be applied a week prior to harvest during the ripe stage of physiological maturity. However, some grains may not be at this physiological stage due to non-uniform maturation within the field. The goal of this study was to determine the effect of glyphosate-based herbicide timing on the chemistry of wheat gluten proteins and shikimic acid accumulation. The results of the study indicate that pre-harvest glyphosate application does not impact the amino acid composition, protein secondary structure or gluten protein composition. However, pre-harvest glyphosate application decreased the molecular weight of SDS extractable and unextractable proteins, and significantly increased the amount of shikimic acid accumulation, especially when applied early. Thus, this study indicates that pre-harvest use of glyphosate-based herbicides can cause significant differences in wheat protein chemistry and shikimic acid levels, especially when applied earlier than recommended, emphasizing the importance of timely application.


Assuntos
Glicina/análogos & derivados , Herbicidas/farmacologia , Proteínas de Plantas/metabolismo , Ácido Chiquímico/metabolismo , Triticum/efeitos dos fármacos , Aminoácidos/análise , Aminoácidos/metabolismo , Glutens/análise , Glutens/metabolismo , Glicina/farmacologia , Proteínas de Plantas/análise , Ácido Chiquímico/análise , Triticum/química , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
8.
Int J Food Microbiol ; 331: 108712, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32563775

RESUMO

The bread-making quality of wheat depends on the viscoelastic properties of the dough in which gluten proteins play an important role. The quality of gluten proteins is influenced by the genetics of the different wheat varieties and environmental factors. Occasionally, a near complete loss of gluten strength, measured as the maximum resistance towards stretching (Rmax), is observed in grain lots of Norwegian wheat. It is hypothesized that the loss of gluten quality is caused by degradation of gluten proteins by fungal proteases. To identify fungi associated with loss of gluten strength, samples from a selection of wheat grain lots with weak gluten (n = 10, Rmax < 0.3 N) and strong gluten (n = 10, Rmax ≥ 0.6 N) was analyzed for the abundance of fungal operational taxonomic units (OTUs) using DNA metabarcoding of the nuclear ribosomal Internal Transcribed Spacer (ITS) region ITS1. The DNA quantities for a selection of fungal pathogens of wheat, and the total amount of fungal DNA, were analyzed by quantitative PCR (qPCR). The mean level of total fungal DNA was higher in grain samples with weak gluten compared to grain samples with strong gluten. Heightened quantities of DNA from fungi within the Fusarium Head Blight (FHB) complex, i.e. Fusarium avenaceum, Fusarium graminearum, Microdochium majus, and Microdochium nivale, were observed in grain samples with weak gluten compared to those with strong gluten. Microdochium majus was the dominant fungus in the samples with weak gluten. Stepwise regression modeling based on different wheat quality parameters, qPCR data, and the 35 most common OTUs revealed a significant negative association between gluten strength and three OTUs, of which the OTU identified as M. majus was the most abundant. The same analysis also revealed a significant negative relationship between gluten strength and F. avenaceum detected by qPCR, although the DNA levels of this fungus were low compared to those of M. majus. In vitro growth rate studies of a selection of FHB species showed that all the tested isolates were able to grow with gluten as a sole nitrogen source. In addition, proteins secreted by these fungi in liquid cultures were able to hydrolyze gluten substrate proteins in zymograms, confirming their capacity to secrete gluten-degrading proteases. The identification of fungi with potential to influence gluten quality can enable the development of strategies to minimize future problems with gluten strength in food-grade wheat.


Assuntos
Microbiologia de Alimentos , Fungos/classificação , Glutens/química , Triticum/química , Triticum/microbiologia , DNA Fúngico/genética , Grão Comestível/microbiologia , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Glutens/metabolismo , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase em Tempo Real , Triticum/metabolismo
9.
Food Chem ; 327: 127048, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454285

RESUMO

In our previous study, a novel LMW-GS designated as LMW-N13 with a unique molecular structure was identified from Aegilops uniaristata. LMW-N13 has been characterized as the largest LMW-GS, so far, and possesses an extra cysteine residue compared with typical LMW-GS. In order to analyze the contribution of LMW-N13 to dough quality, in this work, three transgenic wheat lines overexpressing LMW-N13 were generated. Compared with non-transformation (NT) lines, transgenic (TG) lines demonstrated superior dough properties. These superior dough properties were accompanied by the higher contents of glutenin macropolymer (GMP) and total protein. The microstructure of the dough was further investigated by scanning electron microscopy; starch granules in NT lines were smaller than those in transgenic lines. The protein matrix in NT lines was relatively loose and discontinuous. Conversely, the protein matrix in transgenic lines was more continuous and tight. The application of LMW-N13 in wheat breeding is also discussed.


Assuntos
Farinha/análise , Glutens/química , Plantas Geneticamente Modificadas/química , Triticum/química , Aegilops/genética , Dissulfetos/química , Glutens/genética , Glutens/metabolismo , Microscopia Eletrônica de Varredura , Peso Molecular , Plantas Geneticamente Modificadas/metabolismo , Amido/química , Triticum/metabolismo , Água/química
10.
PLoS One ; 15(4): e0229535, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32315299

RESUMO

Colored wheat is a valuable resource that is rich in anthocyanins and minerals and thus contributes additional nutritional value to a healthy human diet. However, the effects of nitrogen fertilization on anthocyanin content (AC) and the balance between quality and yield still merit discussion. In this study, blue, purple, and common-colored wheat genotypes were used to investigate three nutrient quality traits, seven processing quality traits, three yield traits and seven grain morphology traits at three nitrogen levels in two years to excavate their possible plasticity under low-nitrogen stress and the tradeoffs among these traits. The highest AC was found in the blue genotypes followed by the purple genotypes. Analysis of variance (ANOVA) showed that AC could be significantly increased by reducing N application, especially in the purple genotypes. Therefore, growing colored wheat with low nitrogen input could allow efficient harvesting of grain with higher AC. However, the other nutrient quality traits and most processing quality traits were observed to decrease under low-nitrogen (LN) stress. Additionally, a correlation analysis indicated that the nutrient quality traits had stable tradeoffs with thousand kernel weight at all N levels because of the significantly negative correlations among them. Therefore, the additive main effect and multiplicative interaction (AMMI) model was used to further identify the most suitable colored genotypes with the best yield potential and also nutrient quality relative characteristics under LN stress. The blue lines Lanmai2999 and purple varieties Zhongkezinuomai 168 were found to be specifically adapted to LN stress with the highest AC values and showed stable performance in the other nutrient quality- and yield-related features. To further investigate the possible mechanism of anthocyanin accumulation in response to reduced N application, the expression of four genes (TaCHS, TaFDR, TaCHI and TaANS) involved in the anthocyanin synthesis pathway was evaluated. All four genes were downregulated under high nitrogen fertilizer application, indicating that anthocyanin synthesis in colored wheat might be inhibited by nitrogen fertilizer. Therefore, this research provided information for optimizing nitrogen fertilizer management in producing colored wheat and also demonstrated that it is efficient and economical to plant colored wheat genotypes in nitrogen-poor areas for use in a healthy human diet, improving the benefits of wheat planting and facilitating nitrogen pollution control.


Assuntos
Antocianinas/genética , Grão Comestível/genética , Nitrogênio/metabolismo , Triticum/genética , Grão Comestível/crescimento & desenvolvimento , Fertilizantes , Regulação da Expressão Gênica de Plantas/genética , Genótipo , Glutens/metabolismo , Humanos , Nutrientes , Fenótipo , Melhoramento Vegetal , Proteínas de Plantas/genética , Triticum/crescimento & desenvolvimento
11.
Food Chem ; 324: 126840, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32344339

RESUMO

Functional foods have created an open environment for the development of new solutions to health-related issues. In celiac disease, there is still no therapeutic alternative other than the observance of a gluten-free diet. In this context, we developed a wheat flour enriched in l-theanine aimed to be a potential alternative to the gluten-free diet. Through microbial transglutaminase-catalysed transamidation of gluten proteins using ethylamine as amine nucleophile, substantial amounts of glutamine residues were converted in theanine residues. Furthermore, using T-cell lines generated from intestinal biopsy specimens of celiac disease patients, this treatment showed the potential to strongly reduce the ability of gluten proteins to stimulate a T-cell-mediated immune response. From a rheological point of view, the functionality of gluten was retained. Considering L-theanine's evidence-based health benefits, a novel functional food is presented here and for celiac disease can be a path towards the development of an alternative to the gluten-free diet.


Assuntos
Doença Celíaca/imunologia , Farinha , Glutamatos/química , Glutens/química , Linfócitos T/imunologia , Doença Celíaca/dietoterapia , Dieta Livre de Glúten , Suplementos Nutricionais , Elasticidade , Etilaminas/metabolismo , Alimento Funcional , Glutens/metabolismo , Humanos , Intestinos/citologia , Intestinos/imunologia , Transglutaminases/metabolismo , Triticum
12.
Int J Mol Sci ; 21(4)2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32085665

RESUMO

Absence of high-molecular-weight glutenin subunit (HMW-GS) Dx2 weakens the gluten quality, but it is unclear how the absence of Dx2 has these effects. Thus, we investigated the gluten quality in terms of cytological, physicochemical, and transcriptional characteristics using two near-isogenic lines with Dx2 absent or present at Glu-D1 locus. Cytological observations showed that absence of Dx2 delayed and decreased the accumulation of protein bodies (PBs), where fewer and smaller PBs formed in the endosperm. The activity and gene expression levels of nitrogen assimilation and proteolysis enzymes were lower in HMW-D1a without Dx2 than HMW-D1p with Dx2, and thus less amino acid was transported for protein synthesis in the grains. The expression pattern of genes encoding Glu-1Dx2+1Dy12 was similar to those of three transcription factors, where these genes were significantly down-regulated in HMW-D1a than HMW-D1p. Three genes involving with glutenin polymerization were also down-regulated in HMW-D1a. These results may explain the changes in the glutenin and glutenin macropolymer (GMP) levels during grain development. Therefore, we suggest that the lower nitrogen metabolism capacity and expression levels of glutenin synthesis-related genes in HMW-D1a accounted for the lower accumulation of glutenin, GMP, and PBs, thereby weakening the structural‒thermal properties of gluten.


Assuntos
Regulação da Expressão Gênica de Plantas , Genes de Plantas , Loci Gênicos , Glutens/genética , Nitrogênio/metabolismo , Triticum/genética , Aminoácidos/metabolismo , Endosperma/crescimento & desenvolvimento , Endosperma/metabolismo , Glutamato-Amônia Ligase/metabolismo , Glutens/biossíntese , Glutens/química , Glutens/metabolismo , Folhas de Planta/metabolismo , Polimerização , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Temperatura , Transaminases/metabolismo , Transcrição Genética
13.
Adv Neurobiol ; 24: 469-479, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32006368

RESUMO

Autism spectrum disorder (ASD) is an inherited neurodevelopmental disorder of social communication and restricted, repetitive behaviors. Much remains unknown about their mechanisms of action and physiological effects. In recent years, there has been a growing interest in nutritional diets, which can be used as a form of therapeutic intervention for ASD with a recent increase in the research being carried out in this field. Selective nutrition therapy for ASD and brain function shows improvement in behavioral changes and reduction in malnutrition seemingly associated with the allergies or food intolerances to gluten. Therefore, a gluten-free diet has yielded positive outcomes giving hope in developing therapy for ASD.


Assuntos
Transtorno do Espectro Autista/dietoterapia , Transtorno do Espectro Autista/imunologia , Dieta Livre de Glúten , Glutens/efeitos adversos , Glutens/imunologia , Transtorno do Espectro Autista/fisiopatologia , Transtorno do Espectro Autista/psicologia , Glutens/metabolismo , Humanos , Hipersensibilidade a Trigo/imunologia , Hipersensibilidade a Trigo/metabolismo
14.
Theor Appl Genet ; 133(3): 751-770, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31907562

RESUMO

KEY MESSAGE: A set of eight SNP markers was developed to facilitate the early selection of HMW-GS alleles in breeding programmes. In bread wheat (Triticum aestivum), the high molecular weight glutenin subunits (HMW-GSs) are the most important determinants of technological quality. Known to be very diverse, HMW-GSs are encoded by the tightly linked genes Glu-1-1 and Glu-1-2. Alleles that improve the quality of dough have been identified. Up to now, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of grain proteins is the most widely used for their identification. To facilitate the early selection of HMW-GS alleles in breeding programmes, we developed DNA-based molecular markers. For each accession of a core collection (n = 364 lines) representative of worldwide bread wheat diversity, HMW-GSs were characterized by both genotyping and SDS-PAGE. Based on electrophoresis, we observed at least 8, 22 and 9 different alleles at the Glu-A1, Glu-B1 and Glu-D1 loci, respectively, including new variants. We designed a set of 17 single-nucleotide polymorphism (SNP) markers that were representative of the most frequent SDS-PAGE alleles at each locus. At Glu-A1 and Glu-D1, two and three marker-based haplotypes, respectively, captured the diversity of the SDS-PAGE alleles rather well. Discrepancies were found mainly for the Glu-B1 locus. However, statistical tests revealed that two markers at each Glu-B1 gene and their corresponding haplotypes were more significantly associated with the rheological properties of the dough than were the relevant SDS-PAGE alleles. To conclude, this study demonstrates that the SNP markers developed provide additional information on HMW-GS diversity. Two markers at Glu-A1, four at Glu-B1 and two at Glu-D1 constitute a useful toolbox for breeding wheat to improve end-use value.


Assuntos
Glutens/genética , Glutens/metabolismo , Melhoramento Vegetal/métodos , Triticum/genética , Alelos , Eletroforese em Gel de Poliacrilamida , Genes de Plantas , Marcadores Genéticos , Haplótipos , Peso Molecular , Polimorfismo de Nucleotídeo Único , Triticum/metabolismo
15.
Proc Natl Acad Sci U S A ; 117(6): 3063-3073, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-31974305

RESUMO

The highly homologous human leukocyte antigen (HLA)-DQ2 molecules, HLA-DQ2.5 and HLA-DQ2.2, are implicated in the pathogenesis of celiac disease (CeD) by presenting gluten peptides to CD4+ T cells. However, while HLA-DQ2.5 is strongly associated with disease, HLA-DQ2.2 is not, and the molecular basis underpinning this differential disease association is unresolved. We here provide structural evidence for how the single polymorphic residue (HLA-DQ2.5-Tyr22α and HLA-DQ2.2-Phe22α) accounts for HLA-DQ2.2 additionally requiring gluten epitopes possessing a serine at the P3 position of the peptide. In marked contrast to the biased T cell receptor (TCR) usage associated with HLA-DQ2.5-mediated CeD, we demonstrate with extensive single-cell sequencing that a diverse TCR repertoire enables recognition of the immunodominant HLA-DQ2.2-glut-L1 epitope. The crystal structure of two CeD patient-derived TCR in complex with HLA-DQ2.2 and DQ2.2-glut-L1 (PFSEQEQPV) revealed a docking strategy, and associated interatomic contacts, which was notably distinct from the structures of the TCR:HLA-DQ2.5:gliadin epitope complexes. Accordingly, while the molecular surfaces of the antigen-binding clefts of HLA-DQ2.5 and HLA-DQ2.2 are very similar, differences in the nature of the peptides presented translates to differences in responding T cell repertoires and the nature of engagement of the respective antigen-presenting molecules, which ultimately is associated with differing disease penetrance.


Assuntos
Doença Celíaca , Antígenos HLA-DQ , Receptores de Antígenos de Linfócitos T , Linfócitos T CD4-Positivos/química , Linfócitos T CD4-Positivos/metabolismo , Doença Celíaca/genética , Doença Celíaca/imunologia , Doença Celíaca/metabolismo , Linhagem Celular , Cristalografia por Raios X , Epitopos de Linfócito T/química , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/metabolismo , Glutens/química , Glutens/imunologia , Glutens/metabolismo , Antígenos HLA-DQ/química , Antígenos HLA-DQ/genética , Antígenos HLA-DQ/metabolismo , Humanos , Modelos Moleculares , Ligação Proteica , Receptores de Antígenos de Linfócitos T/química , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo
16.
J Plant Physiol ; 245: 153109, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31896032

RESUMO

OsERdj7 is one of six endoplasmic reticulum (ER)-resident J-domain-containing proteins (J-proteins) encoded by the rice genome that acts as a co-chaperone for Hsp70 and is characterized by the presence of two transmembrane domains. It is N-glycosylated and primarily exists in a dimeric form with a molecular mass of 64 kDa. When the microsomal fraction of maturing seeds was treated with alkaline, high salt or detergent compounds, OsERdj7 was solubilized, even in alkaline and high salt environments, indicating that it is not tightly integrated in the ER membrane. Next, to investigate its role during seed maturation, expression of OsERdj7 was specifically downregulated using RNA interference (RNAi) under the control of the endosperm-specific 16 kDa prolamin promoter in transgenic rice. As a result, the unfolded protein response (UPR) was induced in maturing seeds via activation of OsIRE1/OsbZIP50 and ATF6 orthologs, such as OsbZIP39 and OsbZIP60, leading to upregulation of several chaperones and folding enzymes. Furthermore, some prolamins (RM4 and RM9) were retained in the ER lumen in the form of a mesh-like structure without deposition to the inherent ER-derived protein bodies (PB-Is), although major storage protein glutelins were normally transported to protein storage vacuoles (PB-IIs). On the other hand, induction of ER associated degradation (ERAD) increased OsERdj7 expression in transgenic rice seeds in which ERAD related genes were highly expressed. Due to PDIL2-3 and OsHard3 co-immunoprecipitating with OsERdj7 in rice protoplasts, this result implicates OsERdj7 in the translocation of some seed proteins within the ER lumen and in the degradation of misfolded or unfolded proteins.


Assuntos
Estresse do Retículo Endoplasmático/genética , Degradação Associada com o Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Endosperma/metabolismo , Chaperonas Moleculares/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Fator 6 Ativador da Transcrição/genética , Fator 6 Ativador da Transcrição/metabolismo , Endosperma/enzimologia , Endosperma/genética , Regulação da Expressão Gênica de Plantas/genética , Glutens/metabolismo , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Oryza/genética , Plantas Geneticamente Modificadas/genética , Prolaminas/metabolismo , Domínios Proteicos , Sementes/enzimologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Vacúolos/metabolismo
17.
Theor Appl Genet ; 133(2): 517-528, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31732753

RESUMO

KEY MESSAGE: An expressed HMW glutenin subunit Glu-Ay showed positive impacts on a range of wheat processing quality and yield traits. The grain protein compositions are significantly optimised for baking, resulting in a better breadmaking quality. The unique breadmaking properties of wheat flour are related to the quality and quantity of high-molecular weight glutenin subunits (HMW-GSs) present in the grain. In the current study, the silent 1Ay HMW-GS allele, present in most bread wheat cultivars, was replaced by the expressed 1Ay21* allele, which was introgressed into Australian bread wheat cultivar Lincoln by a backcrossing and selfing scheme. Stability of gene expression and the effect of the introgressed 1Ay21* subunit on protein composition, agronomic traits, flour functionality, and breadmaking quality were studied using BC4F5 grain grown in glasshouse and field. Field phenotyping and grain quality testing showed that the 1Ay21* gene conferred significant improvements to a range of traits, including an increase in grain protein content by up to 9%, UPP% by up to 24%, bread volume by up to 28%. The glasshouse experiment and one of the field trials showed positive 1Ay21* effects on yield, while one field trial showed one significant effects. This indicates that expression of the 1Ay21* gene has the potential of simultaneously increasing protein content and grain yield under certain environment. The qualitative improvements of the grain also led to a reduction of the energy required during the baking process in addition to the significant positive effects on bread quality.


Assuntos
Grão Comestível/genética , Glutens/genética , Glutens/metabolismo , Proteínas de Grãos/metabolismo , Triticum/genética , Alelos , Pão/análise , Cromatografia Líquida de Alta Pressão , Grão Comestível/metabolismo , Farinha/análise , Introgressão Genética , Proteínas de Grãos/química , Espectrometria de Massas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Sementes/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho , Triticum/metabolismo
18.
Food Chem ; 305: 125452, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514050

RESUMO

Flakes are an assortment of grain products mainly consumed for breakfast. Most of them are important source of nutrients including minerals. Twenty commercial flakes from different raw materials were included in this study, both gluten (barley, rye, spelt, wheat) and gluten-free (amaranth, buckwheat, corn, quinoa, millet, oat, rice, teff). The content of minerals (Ca, Fe, K, Mg, Mn, Na and Zn), dietary fiber (total, soluble and insoluble), tannins and phytates was determined. Moreover, the phytates:mineral molar ratios and the percentage of the realization of mineral requirements were calculated. For the first time the mineral bioavailability from the gluten and gluten-free flakes was evaluated and compared. It allowed indicating amaranth and teff products as flakes with the highest impact on the realization of daily requirements for minerals, especially for magnesium and iron. This aspect is particularly important for people on a gluten-free diet who often represent mineral deficiencies.


Assuntos
Fibras na Dieta/análise , Minerais/análise , Ácido Fítico/análise , Taninos/análise , Disponibilidade Biológica , Chenopodium quinoa/química , Chenopodium quinoa/metabolismo , Grão Comestível/química , Fagopyrum/química , Fagopyrum/metabolismo , Glutens/metabolismo , Hordeum/química , Hordeum/metabolismo , Milhetes/química , Milhetes/metabolismo , Espectrofotometria Atômica , Triticum/química , Triticum/metabolismo
19.
Food Chem ; 311: 125892, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31791724

RESUMO

In this study, we successfully knock-out the d-hordein component of barley storage protein using RNA-guided Cas9. Mutation frequencies of 25% and 14% at two different target sites were obtained. Homozygous mutant plants that were T-DNA free were identified in the T1 generation. Barley grains without d-hordein proteins from T2 seeds showed a significantly reduced grain size compared to the parent plant and control non-edited line. The protein matrix surrounding the starch granules was increased, whereas the starch granules themselves were decreased in size in the mutant plants compared to controls. The main effect of a lack of d-hordein was a considerable decrease in the prolamines and an increase in the glutenins. The changes of other grain composition included the increased starch content, amylose content, and ß-glucan content. The roles of d-hordein mutation on barley grain size and grain composition remain to be studied.


Assuntos
Sistemas CRISPR-Cas/genética , Glutens/genética , Hordeum/metabolismo , RNA Guia/metabolismo , Edição de Genes , Glutens/metabolismo , Hordeum/genética , Hordeum/crescimento & desenvolvimento , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Prolaminas/metabolismo , RNA Guia/genética , Sementes/genética , Sementes/metabolismo , Amido/metabolismo , beta-Glucanas/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...