305 research outputs found

    Efecto del proceso tecnológico sobre la capacidad antioxidante y compuestos fenólicos totales del lupino (Lupinus mutabilis Sweet) andino

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    The effect of debittering, extrusion and spray drying on antioxidant capacity and total phenolic compounds in non-defatted and defatted flours from three Andean lupine genotypes (Altagracia, Andenes, and Yunguyo) was evaluated. Total phenolic content (TPC; Folin-Ciocalteu method) and antioxidant capacity (DPPH and ABTS+) were assessed by spectrophotometry. Results showed that technological processes decreased significantly (p ≤ 0.05) antioxidants and phenolic compounds. Bitter lupine (control sample) had higher (p ≤ 0.05) TPC and antioxidant capacity than processed samples. In non-defatted and defatted samples, TPC of processed samples varied between 0.64 - 1.10 and 0.75 - 1.33 mg gallic acid equivalent/g d.m. in non-defatted and defatted samples, respectively. The DPPH antioxidant capacity varied between 2.87 - 4.10 and 3.12 - 4.73 μmol Trolox/g d.m., while the ABTS+ antioxidant capacity ranged between 50.65 - 75.56 and 61.63 - 76.88 μmol Trolox/g d.m. in non-defatted and defatted samples, respectively. On the other hand, lipids negatively influenced the quantification of TPC; therefore, the defatted samples had higher TPC.Se evaluó el efecto del desamargado, la extrusión y el secado por aspersión sobre la capacidad antioxidante y los compuestos fenólicos totales en harinas no desgrasadas y desgrasadas de tres genotipos de lupino andino (Altagracia, Andenes y Yunguyo). El contenido de fenólicos totales (TPC; método Folin-Ciocalteu) y la capacidad antioxidante (DPPH y ABTS+) se evaluaron por espectrofotometría. Los resultados mostraron que los procesos tecnológicos disminuyeron significativamente (p ≤ 0,05) antioxidantes y compuestos fenólicos. El lupino amargo (muestra de control) tenía una mayor capacidad de TPC y antioxidante (p ≤ 0,05) que las muestras procesadas. En muestras no desgrasadas y desgrasadas, el TPC de las muestras procesadas varió entre 0,64 - 1,10 y 0,75 - 1,33 mg de ácido gálico equivalente/g b.s., en muestras no desgrasadas y desgrasadas, respectivamente. La capacidad antioxidante DPPH varió entre 2,87 - 4,10 y 3,12 - 4,73 μmol Trolox/g b.s, mientras que la capacidad antioxidante ABTS+ varió entre 50,65 - 75,56 y 61,63 - 76,88 μmol Trolox/g b.s., en muestras no desgrasadas y desgrasadas, respectivamente. Por otro lado, los lípidos influyeron negativamente en la cuantificación de TPC; por lo tanto, las muestras desgrasadas tenían un TPC más alto

    Analysis of the genome and transcriptome of Cryptococcus neoformans var. grubii reveals complex RNA expression and microevolution leading to virulence attenuation.

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    Cryptococcus neoformans is a pathogenic basidiomycetous yeast responsible for more than 600,000 deaths each year. It occurs as two serotypes (A and D) representing two varieties (i.e. grubii and neoformans, respectively). Here, we sequenced the genome and performed an RNA-Seq-based analysis of the C. neoformans var. grubii transcriptome structure. We determined the chromosomal locations, analyzed the sequence/structural features of the centromeres, and identified origins of replication. The genome was annotated based on automated and manual curation. More than 40,000 introns populating more than 99% of the expressed genes were identified. Although most of these introns are located in the coding DNA sequences (CDS), over 2,000 introns in the untranslated regions (UTRs) were also identified. Poly(A)-containing reads were employed to locate the polyadenylation sites of more than 80% of the genes. Examination of the sequences around these sites revealed a new poly(A)-site-associated motif (AUGHAH). In addition, 1,197 miscRNAs were identified. These miscRNAs can be spliced and/or polyadenylated, but do not appear to have obvious coding capacities. Finally, this genome sequence enabled a comparative analysis of strain H99 variants obtained after laboratory passage. The spectrum of mutations identified provides insights into the genetics underlying the micro-evolution of a laboratory strain, and identifies mutations involved in stress responses, mating efficiency, and virulence

    Role of Plant-Specific N-Terminal Domain of Maize CK2β1 Subunit in CK2β Functions and Holoenzyme Regulation

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    Protein kinase CK2 is a highly pleiotropic Ser/Thr kinase ubiquituous in eukaryotic organisms. CK2 is organized as a heterotetrameric enzyme composed of two types of subunits: the catalytic (CK2α) and the regulatory (CK2β). The CK2β subunits enhance the stability, activity and specificity of the holoenzyme, but they can also perform functions independently of the CK2 tetramer. CK2β regulatory subunits in plants differ from their animal or yeast counterparts, since they present an additional specific N-terminal extension of about 90 aminoacids that shares no homology with any previously characterized functional domain. Sequence analysis of the N-terminal domain of land plant CK2β subunit sequences reveals its arrangement through short, conserved motifs, some of them including CK2 autophosphorylation sites. By using maize CK2β1 and a deleted version (ΔNCK2β1) lacking the N-terminal domain, we have demonstrated that CK2β1 is autophosphorylated within the N-terminal domain. Moreover, the holoenzyme composed with CK2α1/ΔNCK2β1 is able to phosphorylate different substrates more efficiently than CK2α1/CK2β1 or CK2α alone. Transient overexpression of CK2β1 and ΔNCK2β1 fused to GFP in different plant systems show that the presence of N-terminal domain enhances aggregation in nuclear speckles and stabilizes the protein against proteasome degradation. Finally, bimolecular fluorescence complementation (BiFC) assays show the nuclear and cytoplasmic location of the plant CK2 holoenzyme, in contrast to the individual CK2α/β subunits mainly observed in the nucleus. All together, our results support the hypothesis that the plant-specific N-terminal domain of CK2β subunits is involved in the down-regulation of the CK2 holoenzyme activity and in the stabilization of CK2β1 protein. In summary, the whole amount of data shown in this work suggests that this domain was acquired by plants for regulatory purposes

    The yield of essential oils in Melaleuca alternifolia (Myrtaceae) is regulated through transcript abundance of genes in the MEP pathway

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    Medicinal tea tree (Melaleuca alternifolia) leaves contain large amounts of an essential oil, dominated by monoterpenes. Several enzymes of the chloroplastic methylerythritol phosphate (MEP) pathway are hypothesised to act as bottlenecks to the production of monoterpenes. We investigated, whether transcript abundance of genes encoding for enzymes of the MEP pathway were correlated with foliar terpenes in M. alternifolia using a population of 48 individuals that ranged in their oil concentration from 39 -122 mg x g DM(-1). Our study shows that most genes in the MEP pathway are co-regulated and that the expression of multiple genes within the MEP pathway is correlated with oil yield. Using multiple regression analysis, variation in expression of MEP pathway genes explained 87% of variation in foliar monoterpene concentrations. The data also suggest that sesquiterpenes in M. alternifolia are synthesised, at least in part, from isopentenyl pyrophosphate originating from the plastid via the MEP pathway

    Digital Gene Expression Profiling by 5′-End Sequencing of cDNAs during Reprogramming in the Moss Physcomitrella patens

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    Stem cells self-renew and repeatedly produce differentiated cells during development and growth. The differentiated cells can be converted into stem cells in some metazoans and land plants with appropriate treatments. After leaves of the moss Physcomitrella patens are excised, leaf cells reenter the cell cycle and commence tip growth, which is characteristic of stem cells called chloronema apical cells. To understand the underlying molecular mechanisms, a digital gene expression profiling method using mRNA 5′-end tags (5′-DGE) was established. The 5′-DGE method produced reproducible data with a dynamic range of four orders that correlated well with qRT-PCR measurements. After the excision of leaves, the expression levels of 11% of the transcripts changed significantly within 6 h. Genes involved in stress responses and proteolysis were induced and those involved in metabolism, including photosynthesis, were reduced. The later processes of reprogramming involved photosynthesis recovery and higher macromolecule biosynthesis, including of RNA and proteins. Auxin and cytokinin signaling pathways, which are activated during stem cell formation via callus in flowering plants, are also activated during reprogramming in P. patens, although no exogenous phytohormone is applied in the moss system, suggesting that an intrinsic phytohormone regulatory system may be used in the moss
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