136 research outputs found

    Lipolysis kinetics of milk-fat catalyzed by an enzymatic supplement under simulated gastrointestinal conditions

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    [EN] Pancreatic insufficiency is a clinical manifestation characterized by the in-ability of the pancreas to release enough pancreatic enzyme into the small intestine, necessary to digest intraluminal nutrients. The lack of digestive enzymes leads to the difficulty to absorb nutrients, which drives in infants, to malnutrition and lack of growth and development, due to the loss of calories. These patients generally need oral administration of enzymes to favor lipolysis and absorption of lipids from foods. However, there are a number of food related factors (matrix, type of fat, etc.) and digestive environment (intestinal pH, bile concentration, among others), which will influence the digestibility of nutrients. In this study, an "in vitro" digestion model was used to characterize the kinetics of the lipolysis of milk-fat catalyzed by an enzymatic supplement. Different intestinal conditions (pH (6, 7 and 8) and bile concentrations (1, 5 and 10 mml L-1)) were simulated, using a fixed concentration of supplement. Gastro-Intestinal conditions, significantly affected lipolysis. High pH and bile concentrations were translated into low values of the Michaelis-Menten constant and high values of the catalytic constant. The kinetic parameters obtained from this work allowed estimating the dose of enzymatic supplement required to optimize the lipolysis of milk-fat under different intestinal environments, sufficient and insufficient pancreatic conditions.Authors of this paper, on behalf of MyCyFAPP consortium, acknowledge the European Union and the Horizon 2020 Research and Innovation Framework Programme for funding the above-mentioned project under grant agreement number 643806.Peinado Pardo, I.; Larrea Santos, V.; Heredia Gutiérrez, AB.; Andrés Grau, AM. (2018). Lipolysis kinetics of milk-fat catalyzed by an enzymatic supplement under simulated gastrointestinal conditions. Food Bioscience. 23:1-8. https://doi.org/10.1016/j.fbio.2018.02.011S182

    Assessing European wheat sensitivities to parastagonospora nodorum necrotrophic effectors and fine-mapping the Snn3-B1 locus conferring sensitivity to the effector SnTox3

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    © 2018 Downie, Bouvet, Furuki, Gosman, Gardner, Mackay, Campos Mantello, Mellers, Phan, Rose, Tan, Oliver and Cockram. Parastagonospora nodorum is a necrotrophic fungal pathogen of wheat (Triticum aestivum L.), one of the world’s most important crops. P. nodorum mediates host cell death using proteinaceous necrotrophic effectors, presumably liberating nutrients that allow the infection process to continue. The identification of pathogen effectors has allowed host genetic resistance mechanisms to be separated into their constituent parts. In P. nodorum, three proteinaceous effectors have been cloned: SnToxA, SnTox1, and SnTox3. Here, we survey sensitivity to all three effectors in a panel of 480 European wheat varieties, and fine-map the wheat SnTox3 sensitivity locus Snn3-B1 using genome-wide association scans (GWAS) and an eight-founder wheat multi-parent advanced generation inter-cross (MAGIC) population. Using a Bonferroni corrected P = 0.05 significance threshold, GWAS identified 10 significant markers defining a single locus, Snn3-B1, located on the short arm of chromosome 5B explaining 32% of the phenotypic variation [peak single nucleotide polymorphisms (SNPs), Excalibur_c47452_183 and GENE-3324_338, -log10P = 20.44]. Single marker analysis of SnTox3 sensitivity in the MAGIC population located Snn3-B1 via five significant SNPs, defining a 6.2-kb region that included the two peak SNPs identified in the association mapping panel. Accordingly, SNP Excalibur_c47452_183 was converted to the KASP genotyping system, and validated by screening a subset of 95 wheat varieties, providing a valuable resource for marker assisted breeding and for further genetic investigation. In addition, composite interval mapping in the MAGIC population identified six minor SnTox3 sensitivity quantitative trait loci, on chromosomes 2A (QTox3.niab-2A.1, P-value = 9.17-7), 2B (QTox3.niab-2B.1, P = 0.018), 3B (QTox3.niab-3B.1, P = 48.51-4), 4D (QTox3.niab-4D.1, P = 0.028), 6A (QTox3.niab-6A.1, P = 8.51-4), and 7B (QTox3.niab-7B.1, P = 0.020), each accounting for between 3.1 and 6.0 % of the phenotypic variance. Collectively, the outcomes of this study provides breeders with knowledge and resources regarding the sensitivity of European wheat germplasm to P. nodorum effectors, as well as simple diagnostic markers for determining allelic state at Snn3-B1

    Biology and epidemiology of Venturia species affecting fruit crops: a review

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    [EN] The fungal genus Venturia Sacc. (anamorph Fusicladium Bonord.) includes plant pathogens that cause substantial economic damage to fruit crops worldwide. Although Venturia inaequalis is considered a model species in plant pathology, other Venturia spp. also cause scab on other fruit trees. Relative to the substantial research that has been conducted on V. inaequalis and apple scab, little research has been conducted on Venturia spp. affecting other fruit trees. In this review, the main characteristics of plant-pathogenic species of Venturia are discussed with special attention to V. inaequalis affecting apple, V. pyrina affecting European pear, V. nashicola affecting Asian pear, V. carpophila affecting peach and almond, Fusicladium oleagineum affecting olive, F. effusum affecting pecan, and F. eriobotryae affecting loquat. This review has two main objectives: (i) to identify the main gaps in our knowledge regarding the biology and epidemiology of Venturia spp. affecting fruit trees; and (ii) to identify similarities and differences among these Venturia spp. in order to improve disease management. A thorough review has been conducted of studies regarding the phylogenetic relationships, host ranges, biologies, and epidemiologies of Venturia spp. A multiple correspondence analysis (CA) has also been performed on the main epidemiological components of these Venturia spp. CA separated the Venturia spp. into two main groups, according to their epidemiological behavior: the first group included V. inaequalis, V. pyrina, V. nashicola, and V. carpophila, the second F. oleagineum and F. eriobotryae, with F. effusum having an intermediate position. This review shows that Venturia spp. affecting fruit trees are highly host-specific, and that important gaps in understanding the life cycle exist for some species, including V. pyrina; gaps include pseudothecia formation, ascospore and conidia germination, and mycelial growth. Considering the epidemiological information reviewed, this paper shows that the use of Mills tables to predict infection periods should be avoided for Venturia spp. other than V. inaequalis.This work was supported by “Instituto Nacional de Investigaciones Agrarias (INIA)” grant number RTA2013-00004-C03-03, and FEDER Funds.González Domínguez, E.; Armengol Fortí, J.; Rossi, V. (2017). Biology and epidemiology of Venturia species affecting fruit crops: a review. Frontiers in Plant Science. 8. https://doi.org/10.3389/fpls.2017.01496S

    A study on trypsin, Aspergillus flavus and Bacillus sp. protease inhibitory activity in Cassia tora (L.) syn Senna tora (L.) Roxb. seed extract

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    <p>Abstract</p> <p>Background</p> <p>Proteases play an important role in virulence of many human, plant and insect pathogens. The proteinaceous protease inhibitors of plant origin have been reported widely from many plant species. The inhibitors may potentially be used for multiple therapeutic applications in viral, bacterial, fungal diseases and physiological disorders. In traditional Indian medicine system, <it>Cassia tora </it>(<it>Senna tora</it>) is reportedly effective in treatment of skin and gastrointestinal disorders. The present study explores the protease inhibitory activity of the above plant seeds against trypsin, <it>Aspergillus flavus </it>and <it>Bacillus </it>sp. proteases.</p> <p>Methods</p> <p>The crushed seeds of <it>Cassia tora </it>were washed thoroughly with acetone and hexane for depigmentation and defatting. The proteins were fractionated by ammonium sulphate (0-30, 30-60, 60-90%) followed by dialysis and size exclusion chromatography (SEC). The inhibitory potential of crude seed extract and most active dialyzed fraction against trypsin and proteases was established by spot test using unprocessed x-ray film and casein digestion methods, respectively. Electrophoretic analysis of most active fraction (30-60%) and SEC elutes were carried employing Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Gelatin SDS-PAGE. Inhibition of fungal spore germination was studied in the presence of dialyzed active inhibitor fraction. Standard deviation (SD) and ANOVA were employed as statistical tools.</p> <p>Results</p> <p>The crude seeds' extract displayed strong antitryptic, bacterial and fungal protease inhibitory activity on x-ray film. The seed protein fraction 30-60% was found most active for trypsin inhibition in caseinolytic assay (P < 0.001). The inhibition of caseinolytic activity of the proteases increased with increasing ratio of seed extract. The residual activity of trypsin, <it>Aspergillus flavus </it>and <it>Bacillus </it>sp. proteases remained only 4, 7 and 3.1%, respectively when proteases were incubated with 3 mg ml<sup>-1 </sup>seed protein extract for 60 min. The inhibitory activity was evident in gelatin SDS-PAGE where a major band (~17-19 kD) of protease inhibitor (PI) was detected in dialyzed and SEC elute. The conidial germination of <it>Aspergillus flavus </it>was moderately inhibited (30%) by the dialyzed seed extract.</p> <p>Conclusions</p> <p><it>Cassia tora </it>seed extract has strong protease inhibitory activity against trypsin, <it>Aspergillus flavus </it>and <it>Bacillus </it>sp. proteases. The inhibitor in <it>Cassia tora </it>may attenuate microbial proteases and also might be used as phytoprotecting agent.</p

    Plant Antimicrobial Agents and Their Effects on Plant and Human Pathogens

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    To protect themselves, plants accumulate an armoury of antimicrobial secondary metabolites. Some metabolites represent constitutive chemical barriers to microbial attack (phytoanticipins) and others inducible antimicrobials (phytoalexins). They are extensively studied as promising plant and human disease-controlling agents. This review discusses the bioactivity of several phytoalexins and phytoanticipins defending plants against fungal and bacterial aggressors and those with antibacterial activities against pathogens affecting humans such as Pseudomonas aeruginosa and Staphylococcus aureus involved in respiratory infections of cystic fibrosis patients. The utility of plant products as “antibiotic potentiators” and “virulence attenuators” is also described as well as some biotechnological applications in phytoprotection

    Chromosomal replication dynamics and interaction with the β sliding clamp determine orientation of bacterial transposable elements

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    Insertion sequences (ISs) are small transposable elements widespread in bacterial genomes, where they play an essential role in chromosome evolution by stimulating recombination and genetic flow. Despite their ubiquity, it is unclear how ISs interact with the host. Here, we report a survey of the orientation patterns of ISs in bacterial chromosomes with the objective of gaining insight into the interplay between ISs and host chromosomal functions. We find that a significant fraction of IS families present a consistent and family-specific orientation bias with respect to chromosomal DNA replication, especially in Firmicutes. Additionally, we find that the transposases of up to nine different IS families with different transposition pathways interact with the β sliding clamp, an essential replication factor, suggesting that this is a widespread mechanism of interaction with the host. Although we find evidence that the interaction with the β sliding clamp is common to all bacterial phyla, it also could explain the observed strong orientation bias found in Firmicutes, because in this group β is asymmetrically distributed during synthesis of the leading or lagging strands. Besides the interaction with the β sliding clamp, other asymmetries also play a role in the biased orientation of some IS families. The utilization of the highly conserved replication sliding clamps suggests a mechanism for host regulation of IS proliferation and also a universal platform for IS dispersal and transmission within bacterial populations and among phylogenetically distant species

    New data on the chronology of the Vale do Forno sedimentary sequence (Lower Tejo River terrace staircase) and its relevance as a fluvial archive of the Middle Pleistocene in western Iberia

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    The Vale do Forno archaeological sites (Alpiar\ue7a, central Portugal) document the earliest human occupation in the Lower Tejo River, well established in geomorphological and environmental terms, within the Middle Pleistocene. In a staircase of six fluvial terraces, the Palaeolithic sites were found on the T4 terrace (\ufe24 m, above river bed) which is made of a basal Lower Gravels unit (LG) and an overlying Upper Sands unit (US). Geomorphological mapping, coupled with lithostratigraphy, sedimentology and luminescence dating (quartz-OSL and K-feldspar post-IRIR290) were used in this study. The oldest artefacts found in the LG unit show crude bifacial forms that can be attributed to the Acheulian. In contrast, the US unit has archaeological sites stratigraphically documenting successive phases of an evolved Acheulian. Luminescence dating and correlation with the Marine Isotopic Stages suggest that the LG unit has a probable age of ca. 335 to 325 ka and the US unit an age of ca. 325 to 155 ka. This is in contrast to previous interpretations ascribing this terrace (and lithic industries) to the Last Interglacial and early phases of the Last Glacial. The VF3 site (Milharos), containing Micoquian (Final Acheulian) industries (with fine and elaborated bifaces), found in a stratigraphic level located between the T4 terrace deposits and a colluvium associated with Late Pleistocene aeolian sands, is younger than 155 ka but much older than 32 ka
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