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31.
The feasibility of pressurized solvents (liquids at a high pressure and/or high temperature without the subcritical point being reached) has been newly investigated to accelerate enzymatic hydrolysis processes of mussel tissue for multielement determinations. The target elements (Al, As, Cd, Co, Cu, Fe, Hg, Li, Mn, Pb, Se, Sr, V, and Zn) were released from dried mussel tissue by action of two proteases (pepsin and pancreatin), and they have been evaluated by inductively coupled plasma optical emission spectrometry (ICP-OES). Variables inherent to the enzymatic activity (pH, ionic strength, temperature, and enzyme mass) and factors affecting pressurization (static time, pressure, and number of cycles) were simultaneously studied by applying a Plackett-Burman design (PBD) as the screening method. Results showed that pH, ionic strength, and temperature were the most statistically significant factors (confidence interval of 95%) under pressurized conditions for pepsin, while pH and ionic strength affected pancreatin activity. This means that metal extraction is mostly attributed to enzymatic activity. The static time (enzymatic hydrolysis time) was found statistically nonsignificant for most of the elements, meaning that the hydrolysis procedure can be finished within a 2-15 min range. For pepsin, optimized conditions (pH 1.0, temperature 40 degrees C, pressure 1500 psi, static time 2 min, and number of cycles 3) gave quantitative extractions for As, Cd, Co, Cu, Hg, Li, Mn, Pb, Se, Sr, V, and Zn. The pepsin mass was 0.05 g, and the solution was Milli-Q water at pH 1.0 (adjusted with hydrochloric acid). For pancreatin, quantitative recoveries were only reached for As, Cd, Cu, Li, Pb, and Sr at room temperature, at a pressure of 1500 psi, for a static time of 2 min and a number of cycles of 3. The extraction solution was a 0.3 M potassium dihydrogen phosphate/potassium hydrogen phosphate buffer at a pH of 7.5 working at room temperature. Around 0.5 g of diatomaceous earth was used as dispersing agent for hydrolyses with either enzyme. Analytical performances, such as limits of detection and quantification and repeatability of the overall procedure, have been established. Finally, accuracy of the methods was assessed by analyzing seafood certified reference materials (GBW-08571, DORM-2, DOLT-3, TORT-2), fatty tissues certified reference materials (BCR 185, NIST 1577b), and fibrous certified reference materials (BCR 62, GBW-08501).  相似文献   
32.
Despite substantial research, the understanding of the chemopreventive mechanisms of soy isoflavones remains challenging. Promising tools, such as metabolomics, can provide now a deeper insight into their biochemical mechanisms. The purpose of this study was to offer a comprehensive assessment of the metabolic alterations induced by genistein, daidzein and a soy seed extract on estrogen responsive (MCF-7) and estrogen non-responsive breast cancer cells (MDA-MB-231), using a global metabolomic approach. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that all test compounds induced a biphasic effect on MCF-7 cells and only a dose-dependent inhibitory effect on MDA-MB-231 cells. Proton nuclear magnetic resonance (1H-NMR) profiling of extracellular metabolites and gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites confirmed that all test compounds shared similar metabolic mechanisms. Exposing MCF-7 cells to stimulatory concentrations of isoflavones led to increased intracellular levels of 6-phosphogluconate and ribose 5-phosphate, suggesting a possible upregulation of the pentose phosphate pathway. After exposure to inhibitory doses of isoflavones, a significant decrease in glucose uptake was observed, especially for MCF-7 cells. In MDA-MB-231 cells, the glutamine uptake was significantly restricted, leading to alterations in protein biosynthesis. Understanding the metabolomic alterations of isoflavones represents a step forward in considering soy and soy derivates as functional foods in breast cancer chemoprevention.  相似文献   
33.
Low oxygen level is a phenomenon often occurring during the cucumber cultivation period. Genes involved in adaptations to stress can be regulated by non-coding RNA. The aim was the identification of long non-coding RNAs (lncRNAs) involved in the response to long-term waterlogging stress in two cucumber haploid lines, i.e., DH2 (waterlogging tolerant—WL-T) and DH4 (waterlogging sensitive—WL-S). Plants, at the juvenile stage, were waterlogged for 7 days (non-primed, 1xH), and after a 14-day recovery period, plants were stressed again for another 7 days (primed, 2xH). Roots were collected for high-throughput RNA sequencing. Implementation of the bioinformatic pipeline made it possible to determine specific lncRNAs for non-primed and primed plants of both accessions, highlighting differential responses to hypoxia stress. In total, 3738 lncRNA molecules were identified. The highest number (1476) of unique lncRNAs was determined for non-primed WL-S plants. Seventy-one lncRNAs were depicted as potentially being involved in acquiring tolerance to hypoxia in cucumber. Understanding the mechanism of gene regulation under long-term waterlogging by lncRNAs and their interactions with miRNAs provides sufficient information in terms of adaptation to the oxygen deprivation in cucumber. To the best of our knowledge, this is the first report concerning the role of lncRNAs in the regulation of long-term waterlogging tolerance by priming application in cucumber.  相似文献   
34.
Ochratoxin A (OTA) is a toxic metabolite produced by Aspergillus and Penicillium fungi. As it can contaminate a wide variety of foodstuffs, maximum permitted levels have been established by the EU and other countries. The methods currently employed to prevent OTA contamination in different commodities are reviewed. Pre-harvest strategies are the most efficient. They are aimed to reduce fungal infection by aplying good agricultural practices. During harvest, the use of clean farming equipment, mechanical damage prevention and overripe or fermented fruits discard are convenient practices. In the post-harvest, storage is the most critical phase. Environmental conditions, in particular moisture and temperature, have to be well-controlled in this stage. Detoxificating treatments and products with protecting effects against OTA toxic action are also outlined.  相似文献   
35.
This review article explores the telocytes’ roles in inflammatory bowel diseases (IBD), presenting the mechanisms and hypotheses related to epithelial regeneration, progressive fibrosis, and dysmotility as a consequence of TCs’ reduced or absent number. Based on the presented mechanisms and hypotheses, we aim to provide a functional model to illustrate TCs’ possible roles in the normal and pathological functioning of the digestive tract. TCs are influenced by the compression of nearby blood vessels and the degree of fibrosis of the surrounding tissues and mediate these processes in response. The changes in intestinal tube vascularization induced by the movement of the food bowl, and the consequent pH changes that show an anisotropy in the thickness of the intestinal tube wall, have led to the identification of a pattern of intestinal tube development based on telocytes’ ability to communicate and modulate surrounding cell functions. In the construction of the theoretical model, given the predictable occurrence of colic in the infant, the two-layer arrangement of the nerve plexuses associated with the intestinal tube was considered to be incompletely adapted to the motility required with a diversified diet. There is resulting evidence of possible therapeutic targets for diseases associated with changes in local nerve tissue development.  相似文献   
36.
Deficiencies in Mannosidase β (MANBA) are associated with neurological abnormalities and recurrent infections. The single nucleotide polymorphism located in the 3′UTR of MANBA, rs7665090, was found to be associated with multiple sclerosis (MS) susceptibility. We aimed to study the functional impact of this polymorphism in lymphocytes isolated from MS patients and healthy controls. A total of 152 MS patients and 112 controls were genotyped for rs7665090. MANBA mRNA expression was quantified through qPCR and MANBA enzymatic activity was analyzed. Upon phytohemagglutinin stimulation, immune activation was evaluated by flow cytometry detection of CD69, endocytic function, and metabolic rates with Seahorse XFp Analyzer, and results were stratified by variation in rs7665090. A significantly reduced gene expression (p < 0.0001) and enzymatic activity (p = 0.018) of MANBA were found in lymphocytes of MS patients compared to those of controls. The rs7665090*GG genotype led to a significant β-mannosidase enzymatic deficiency correlated with lysosomal dysfunction, as well as decreased metabolic activation in lymphocytes of MS patients compared to those of rs7665090*GG controls. In contrast, lymphocytes of MS patients and controls carrying the homozygous AA genotype behaved similarly. Our work provides new evidence highlighting the impact of the MS-risk variant, rs7665090, and the role of MANBA in the immunopathology of MS.  相似文献   
37.
Sixty-one intact meat samples from Asturcelta autochthonous swine breed were scanned in the slaughterhouse in reflectance mode. A handheld microelectromechanical system digital transform (Phazir1624, Polychromix Inc.), with a window sampling area of 0.8?×?1 cm and wavelengths ranging from 1,600 to 2,400 nm, was used. With the spectra database recorded were developed different chemometrical models assaying first and second derivatives as math treatment and standard normal variate (SNV) and multiplicative scatter correction for minimizing scattering effect. The greatest predictive capacity was achieved after applying SNV and first derivative for moisture, intramuscular fat (IMF) content, and pH parameters and second derivative for CIE L*, a*, b* colorimetric values, and the Warner–Bratzler force (instrumental texture). The coefficients of determination for calibration ranged from 0.63 to 0.89. The ratio between the standard error of the laboratory and the standard error of calibration ranged from 0.8 to 2.5 for all parameters (1.7 on average) with the exception of b and pH with ratios of 3.5 and 4.1, respectively. The statistical values obtained for the models developed to estimate IMF, CIE L*, a*, b*, moisture, and pH, displayed acceptable predictive capacity. For instrumental texture, the model could be able to discriminate among tender, medium, and hard meat in carcasses for characterization slaughter purposes.  相似文献   
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39.
Adela Lau  Eric Tsui 《Knowledge》2009,22(4):324-325
The synergies, functional effectiveness and integration of KM within an e-learning environment have attracted little interest for serious research, despite the overarching importance of knowledge acquisition by students for fostering their innovation and creativity. Learners often fail to reach their desired learning objects due to the failure of indexing methods to provide them with a ubiquitous learning grid. The aim of this paper is to discuss how knowledge management can be used effectively in e-learning, and how it can provide a learning grid to enable the learner to identify the right learning objects in an environment which is based on the learner’s context and personal preferences.  相似文献   
40.
Clinical proteomics, a rapidly growing field, intends to use specific diagnostic proteomic/peptidomic markers for initial diagnosis or prognosis of the progression of various diseases. Analyses of disease-associated markers in defined biological samples can provide valuable molecular diagnostic information for these diseases. This approach relies on sensitive and highly standardized modern analytical techniques. In the recent years, one of these technologies, CZE online coupled to MS (CZE-MS), has been increasingly used for the detection of peptide biomarkers (<20 kDa) in body fluids such as urine. This review presents the most relevant urinary proteomic studies addressing the application of CZE-MS in clinically relevant biomarker research between the years 2006 and 2014.  相似文献   
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