19 research outputs found

    A novel (1,4)-beta-linked glucoxylan is synthesized by members of the cellulose synthase-like F gene family in land plants

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    As a significant component of monocot cell walls, (1,3;1,4)-β-glucan has conclusively been shown to be synthesized by the cellulose synthase-like F6 protein. In this study, we investigated the synthetic activity of other members of the barley (Hordeum vulgare) CslF gene family using heterologous expression. As expected, the majority of the genes encode proteins that are capable of synthesizing detectable levels of (1,3;1,4)-β-glucan. However, overexpression of HvCslF3 and HvCslF10 genes resulted in the synthesis of a novel linear glucoxylan that consists of (1,4)-β-linked glucose and xylose residues. To demonstrate that this product was not an aberration of the heterologous system, the characteristic (1,4)-β-linkage between glucose and xylose was confirmed to be present in wild type barley tissues known to contain HvCslF3 and HvCslF10 transcripts. This polysaccharide linkage has also been reported in species of Ulva, a marine green alga, and has significant implications for defining the specificity of the cell wall content of many crop species. This finding supports previous observations that members of a single CSL family may not possess the same carbohydrate synthetic activity, with the CSLF family now associated with the formation of not only (1,3)- and (1,4)-β-glucosidic linkages, but also (1,4)-β-glucosidic and (1,4)-β-xylosidic linkages.Alan Little, Jelle Lahnstein, David W. Jeffery, Shi F. Khor, Julian G. Schwerdt, Neil J. Shirley, Michelle Hooi, Xiaohui Xing, Rachel A. Burton, and Vincent Bulon

    The genetic architecture of type 2 diabetes

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    The genetic architecture of common traits, including the number, frequency, and effect sizes of inherited variants that contribute to individual risk, has been long debated. Genome-wide association studies have identified scores of common variants associated with type 2 diabetes, but in aggregate, these explain only a fraction of heritability. To test the hypothesis that lower-frequency variants explain much of the remainder, the GoT2D and T2D-GENES consortia performed whole genome sequencing in 2,657 Europeans with and without diabetes, and exome sequencing in a total of 12,940 subjects from five ancestral groups. To increase statistical power, we expanded sample size via genotyping and imputation in a further 111,548 subjects. Variants associated with type 2 diabetes after sequencing were overwhelmingly common and most fell within regions previously identified by genome-wide association studies. Comprehensive enumeration of sequence variation is necessary to identify functional alleles that provide important clues to disease pathophysiology, but large-scale sequencing does not support a major role for lower-frequency variants in predisposition to type 2 diabetes

    The trans-ancestral genomic architecture of glycemic traits

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    Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 x 10(-8)), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.A trans-ancestry meta-analysis of GWAS of glycemic traits in up to 281,416 individuals identifies 99 novel loci, of which one quarter was found due to the multi-ancestry approach, which also improves fine-mapping of credible variant sets.Diabetes mellitus: pathophysiological changes and therap

    Microstructure, Crystal structure and ionic conductivity of 3 mol % (Fe, Mn, Co, Zn) doped 8YSZ

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    Effect of 3 mol% of transition elements doped 8YSZ such as YSZZn, YSZFe, YSZCo and YSZMn on the ionic conductivity. SOFCs mostly operate at higher temperature. By substitute with dopants, it can reduce the operating temperature and costs. In this experiment, 3 mol% dopants mixed with 8YSZ and sintered at 1550 °C, hold for two hours. Crystal structure, microstructure, sintering behaviour and ionic conductivity at 300 oC were investigated. XRD demonstrates three phases (cubic, monoclinic and tetragonal) were obtained. It was confirmed that small additions of TMOs (Mn, Fe, Co and Zn) promotes densification, grain growth and ionic conductivity compared to pure 8YSZ. YSZZn obtained the highest ionic conductivity, 3.55 × 10−3 mS cm−1 at 300 °C

    Microstructure, Crystal structure and ionic conductivity of 3 mol % (Fe, Mn, Co, Zn) doped 8YSZ

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    Effect of 3 mol% of transition elements doped 8YSZ such as YSZZn, YSZFe, YSZCo and YSZMn on the ionic conductivity. SOFCs mostly operate at higher temperature. By substitute with dopants, it can reduce the operating temperature and costs. In this experiment, 3 mol% dopants mixed with 8YSZ and sintered at 1550 °C, hold for two hours. Crystal structure, microstructure, sintering behaviour and ionic conductivity at 300 oC were investigated. XRD demonstrates three phases (cubic, monoclinic and tetragonal) were obtained. It was confirmed that small additions of TMOs (Mn, Fe, Co and Zn) promotes densification, grain growth and ionic conductivity compared to pure 8YSZ. YSZZn obtained the highest ionic conductivity, 3.55 × 10−3 mS cm−1 at 300 °C

    The effect of zinc fertilisation and arbuscular mycorrhizal fungi on grain quality and yield of contrasting barley cultivars

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    Zinc is essential for the functioning of many enzymes and plant processes and the malting process. Arbuscular mycorrhizal fungi (AMF) can improve zinc (Zn) uptake in the important cereal crop barley (Hordeum vulgare) on Zn-deficient soils. Here we investigated the impacts of Zn fertilisation and AMF on the yield and grain quality of malting barley cultivars. Five barley genotypes were inoculated or not with the AMF Rhizophagus irregularis, and grown in pots either fertilised with Zn or not. Measurements of Zn nutrition and yield were made for all cultivars. Further analyses of grain biochemical composition, including starch, β-glucan and arabinoxylan contents, and analysis of ATR-MIR spectra were made in two contrasting cultivars. Mycorrhizal colonisation generally resulted in decreased biomass, but increased grain dimensions and mean grain weight. Barley grain yield and biochemical qualities were highly variable between cultivars, and the ATR-MIR spectra revealed grain compositional differences between cultivars and AMF treatments. Mycorrhizal fungi can affect barley grain Zn concentration and starch content, but grain biochemical traits including β-glucan and arabinoxylan contents were more conserved by the cultivar, and unaffected by AMF inoculation. The ATR-MIR spectra revealed that there are other grain characteristics affected by AMF that remain to be elucidated.Ahmed A. Al Mutairi, Timothy R. Cavagnaro, Shi Fang Khor, Kylie Neumann, Rachel A. Burton and Stephanie J. Watts-William
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