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The Diverse Potential of Gluten from Different Durum Wheat Varieties in Triggering Celiac Disease: A Multilevel In Vitro, Ex Vivo and In Vivo Approach.
Gaiani, F, Graziano, S, Boukid, F, Prandi, B, Bottarelli, L, Barilli, A, Dossena, A, Marmiroli, N, Gullì, M, de'Angelis, GL, et al
Nutrients. 2020;(11)
Abstract
The reasons behind the increasing prevalence of celiac disease (CD) worldwide are still not fully understood. This study adopted a multilevel approach (in vitro, ex vivo, in vivo) to assess the potential of gluten from different wheat varieties in triggering CD. Peptides triggering CD were identified and quantified in mixtures generated from simulated gastrointestinal digestion of wheat varieties (n = 82). Multivariate statistics enabled the discrimination of varieties generating low impact on CD (e.g., Saragolla) and high impact (e.g., Cappelli). Enrolled subjects (n = 46) were: 19 healthy subjects included in the control group; 27 celiac patients enrolled for the in vivo phase. Celiacs were divided into a gluten-free diet group (CD-GFD), and a GFD with Saragolla-based pasta group (CD-Sar). The diet was followed for 3 months. Data were compared between CD-Sar and CD-GFD before and after the experimental diet, demonstrating a limited ability of Saragolla to trigger immunity, although not comparable to a GFD. Ex vivo studies showed that Saragolla and Cappelli activated immune responses, although with great variability among patients. The diverse potential of durum wheat varieties in triggering CD immune response was demonstrated. Saragolla is not indicated for celiacs, yet it has a limited potential to trigger adverse immune response.
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Rapid cloning of genes in hexaploid wheat using cultivar-specific long-range chromosome assembly.
Thind, AK, Wicker, T, Šimková, H, Fossati, D, Moullet, O, Brabant, C, Vrána, J, Doležel, J, Krattinger, SG
Nature biotechnology. 2017;(8):793-796
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Abstract
Cereal crops such as wheat and maize have large repeat-rich genomes that make cloning of individual genes challenging. Moreover, gene order and gene sequences often differ substantially between cultivars of the same crop species. A major bottleneck for gene cloning in cereals is the generation of high-quality sequence information from a cultivar of interest. In order to accelerate gene cloning from any cropping line, we report 'targeted chromosome-based cloning via long-range assembly' (TACCA). TACCA combines lossless genome-complexity reduction via chromosome flow sorting with Chicago long-range linkage to assemble complex genomes. We applied TACCA to produce a high-quality (N50 of 9.76 Mb) de novo chromosome assembly of the wheat line CH Campala Lr22a in only 4 months. Using this assembly we cloned the broad-spectrum Lr22a leaf-rust resistance gene, using molecular marker information and ethyl methanesulfonate (EMS) mutants, and found that Lr22a encodes an intracellular immune receptor homologous to the Arabidopsis thaliana RPM1 protein.
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In silico prediction and characterization of secondary metabolite biosynthetic gene clusters in the wheat pathogen Zymoseptoria tritici.
Cairns, T, Meyer, V
BMC genomics. 2017;(1):631
Abstract
BACKGROUND Fungal pathogens of plants produce diverse repertoires of secondary metabolites, which have functions ranging from iron acquisition, defense against immune perturbation, to toxic assaults on the host. The wheat pathogen Zymoseptoria tritici causes Septoria tritici blotch, a foliar disease which is a significant threat to global food security. Currently, there is limited knowledge of the secondary metabolite arsenal produced by Z. tritici, which significantly restricts mechanistic understanding of infection. In this study, we analyzed the genome of Z. tritici isolate IP0323 to identify putative secondary metabolite biosynthetic gene clusters, and used comparative genomics to predict their encoded products. RESULTS We identified 32 putative secondary metabolite clusters. These were physically enriched at subtelomeric regions, which may facilitate diversification of cognate products by rapid gene rearrangement or mutations. Comparative genomics revealed a four gene cluster with significant similarity to the ferrichrome-A biosynthetic locus of the maize pathogen Ustilago maydis, suggesting this siderophore is deployed by Z. tritici to acquire iron. The Z. tritici genome also contains several isoprenoid biosynthetic gene clusters, including one with high similarity to a carotenoid/opsin producing locus in several fungi. Furthermore, we identify putative phytotoxin biosynthetic clusters, suggesting Z. tritici can produce an epipolythiodioxopiperazine, and a polyketide and non-ribosomal peptide with predicted structural similarities to fumonisin and the Alternaria alternata AM-toxin, respectively. Interrogation of an existing transcriptional dataset suggests stage specific deployment of numerous predicted loci during infection, indicating an important role of these secondary metabolites in Z. tritici disease. CONCLUSIONS We were able to assign putative biosynthetic products to numerous clusters based on conservation amongst other fungi. However, analysis of the majority of secondary metabolite loci did not enable prediction of a cluster product, and consequently the capacity of these loci to play as yet undetermined roles in disease or other stages of the Z. tritici lifecycle is significant. These data will drive future experimentation for determining the role of these clusters and cognate secondary metabolite products in Z. tritici virulence, and may lead to discovery of novel bioactive molecules.
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Sensitivity to wheat, gluten and FODMAPs in IBS: facts or fiction?
De Giorgio, R, Volta, U, Gibson, PR
Gut. 2016;(1):169-78
Abstract
IBS is one of the most common types of functional bowel disorder. Increasing attention has been paid to the causative role of food in IBS. Food ingestion precipitates or exacerbates symptoms, such as abdominal pain and bloating in patients with IBS through different hypothesised mechanisms including immune and mast cell activation, mechanoreceptor stimulation and chemosensory activation. Wheat is regarded as one of the most relevant IBS triggers, although which component(s) of this cereal is/are involved remain(s) unknown. Gluten, other wheat proteins, for example, amylase-trypsin inhibitors, and fructans (the latter belonging to fermentable oligo-di-mono-saccharides and polyols (FODMAPs)), have been identified as possible factors for symptom generation/exacerbation. This uncertainty on the true culprit(s) opened a scenario of semantic definitions favoured by the discordant results of double-blind placebo-controlled trials, which have generated various terms ranging from non-coeliac gluten sensitivity to the broader one of non-coeliac wheat or wheat protein sensitivity or, even, FODMAP sensitivity. The role of FODMAPs in eliciting the clinical picture of IBS goes further since these short-chain carbohydrates are found in many other dietary components, including vegetables and fruits. In this review, we assessed current literature in order to unravel whether gluten/wheat/FODMAP sensitivity represent 'facts' and not 'fiction' in IBS symptoms. This knowledge is expected to promote standardisation in dietary strategies (gluten/wheat-free and low FODMAP) as effective measures for the management of IBS symptoms.
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Increased consumption of wheat biofortified with selenium does not modify biomarkers of cancer risk, oxidative stress, or immune function in healthy Australian males.
Wu, J, Salisbury, C, Graham, R, Lyons, G, Fenech, M
Environmental and molecular mutagenesis. 2009;(6):489-501
Abstract
Increased intake of selenium (Se) may reduce the risk of degenerative diseases including cancer but excessive intake may be toxic. Wheat is a major source of dietary Se in humans. However, the effect of Se from wheat that is agronomically biofortified with Se on biomarkers of human health status is unknown. This study aimed to investigate whether improving Se status, by increased dietary intake of Se-biofortified wheat, affects biomarkers of cancer risk, cardiovascular disease risk, oxidative stress, and immune function in healthy South Australian men. A 24-week placebo-controlled double-blind intervention was performed in healthy older men (n = 62), with increased dose of Se intake every 8 weeks. Wheat was provided as 1, 2, and 3 puffed wheat biscuits, during weeks 1-8, 9-16, and 17-24, respectively. Blood was collected to measure a wide range of disease risk biomarkers. Consumption of Se-biofortified wheat was found to increase plasma Se concentration from a baseline level of 122 to 192 microg/L following intake of three biscuits/day, which provided 267 microg Se. Platelet glutathione peroxidase, chromosome aberrations, and DNA damage in lymphocytes measured using the cytokinesis-block micronucleus cytome assay and with the Comet assay, plasma F2-isoprostanes, protein carbonyls, plasma C-reactive protein, and leukocyte number were unaffected by the improved Se status. Improvement of Se status by consumption of Se-biofortified wheat did not substantially modify the selected biomarkers of degenerative disease risk and health status in this apparently selenium-replete cohort of healthy older men in South Australia.
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Effect of wheat gluten hydrolysate on the immune system in healthy human subjects.
Horiguchi, N, Horiguchi, H, Suzuki, Y
Bioscience, biotechnology, and biochemistry. 2005;(12):2445-9
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Abstract
Nine healthy volunteers were divided into a test group (n = 5) and a control group (n = 4). The test group consumed 3 grams per d of wheat gluten hydrolysate for 6 d, and their NK cell activity and hematological parameters were measured: The same assessments were performed in the control group, which did not receive wheat gluten hydrolysate. In the test group, NK cell activity increased significantly (P = 0.018) after wheat gluten hydrolysate intake. No adverse effects were observed in either group.