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1.
1,3-β-Glucans are a class of natural polysaccharides with unique pharmacological properties and the ability to form single- and triple-helical structures that can be formed into resilient gels with the application of heat and humidity. The pharmacological capabilities of 1,3-β-glucans include the impartation of tumor inhibition, resistance to infectious disease, and improvements in wound healing. Curdlan is a linear 1,3-β-glucan that has been used extensively to study the nature of these helical structures and gels, and Curdlan sulfates have found ongoing application in the inhibition of HIV infection. 1,3-β-Glucan gels have been used in food science as stabilizers and encapsulating agents, in nanoscience as scaffolds to build nanofibers and nanowires, and in drug delivery to form nanoparticles and create helical micelles encapsulating polynucleotides. 1,3-β-Glucans are beginning to have enormous significance due to their dual nature as structure-forming agents and pharmacological substances, and research is especially focused on the application of these polymers in animal nutrition and drug delivery.  相似文献   

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1.3-β-Glucanase (laminarinase) activity in soil was measured using laminarin as the substrate. Activity was optimal in sodium acid-maleate buffer at pH 5.4 and followed Michaelis-Menten kinetics. Three methods of analysing kinetic data gave Km values of 0.23, 0.21 and 0.20 mg.ml?1. Vmax values were 0.41, 0.39 and 0.39 μmole glucose, g?1. h?1. The activation energy of the reaction was 49 kJ. mole?1. A proportion of the activity was highly resistant to storage at various temperatures: at 50 C 1,3-β-glucanase had a half-life of 28 days.  相似文献   

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Partial acid hydrolysis of the tetrasaccharide (lycotetraose) side chain of the tomato glycoalkaloid α-tomatine resulted in the formation of four products with three, two, one, and zero carbohydrate side chains, which were separated by high-performance liquid chromatography (HPLC) and identified by thin-layer chromatography (TLC) and liquid chromatography ion-trap time-of-flight mass spectrometry (LCMS-IT-TOF). The inhibitory activities in terms of IC(50) values (concentration that inhibits 50% of the cells under the test conditions) of the parent compound and the hydrolysates, isolated by preparative HPLC, against normal human liver and lung cells and human breast, gastric, and prostate cancer cells indicate that (a) the removal of sugars significantly reduced the concentration-dependent cell-inhibiting effects of the test compounds, (b) PC3 prostate cancer cells were about 10 times more susceptible to inhibition by α-tomatine than the breast and gastric cancer cells or the normal cells, (c) the activity of α-tomatine against the prostate cancer cells was 200 times greater than that of the aglycone tomatidine, and (d) the activity increased as the number of sugars on the aglycone increased, but this was only statistically significant at p < 0.05 for the normal lung Hel299 cell line. The effect of the alkaloids on tumor necrosis factor α (TNF-α) was measured in RAW264.7 macrophage cells. There was a statistically significant negative correlation between the dosage of γ- and α-tomatine and the level of TNF-α. α-Tomatine was the most effective compound at reducing TNF-α. The dietary significance of the results and future research needs are discussed.  相似文献   

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In the present study, four high-pressure (HP) treatments (100, 200, 300, and 400 MPa) of 9 min duration were evaluated to assess their effect on the lipid fraction (fat-soluble vitamins and fatty acid profile) of an orange juice-milk and a vegetable beverage. After HP treatment, nonsignificant changes in vitamin D(2) and D(3) contents were observed for both beverages. An increase in vitamin E activity was observed in HP beverages when pressures >100 MPa were applied, mainly due to an increase in α-tocopherol content. Only a small reduction in fat content was found for the orange juice-milk beverage, but no changes were observed for the vegetable beverage. A significant decrease in SFA levels was observed in HP-treated (300-400 MPa) orange juice-milk. With regard to MUFA, a significant increase in oleic acid (C(18:1)) was found in both liquid foods. Nonsignificant differences in the PUFA profiles were observed after HP processing.  相似文献   

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Milk proteins contain numerous potential bioactive peptides, which may be released by digestive proteases or by the proteolytic system of lactic acid bacteria during food processing. The capacity of Streptococcus thermophilus to generate peptides, especially bioactive peptides, from bovine caseins was investigated. Strains expressing various levels of the cell envelope proteinase, PrtS, were incubated with α(s1)-, α(s2)-, or β-casein. Analysis of the supernatants by LC-ESI-MS/MS showed that the β-casein was preferentially hydrolyzed, followed by α(s2)-casein and then α(s1)-casein. Numbers and types of peptides released were strain-dependent. Hydrolysis appeared to be linked with the accessibility of different casein regions by protease. Analysis of bonds hydrolyzed in the region 1-23 of α(s1)-casein suggests that PrtS is at least in part responsible for the peptide production. Finally, among the generated peptides, 13 peptides from β-casein, 5 from α(s2)-casein, and 2 from α(s1)-casein have been reported as bioactive, 15 of them being angiotensin-converting enzyme inhibitors.  相似文献   

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《广西农业生物科学》2011,30(4):324-324
Legume Genomics and Genetics (LGG) (IS SN 1925-1580 online, http://lgg, sophiapublisher.com) propscd by legume geneticist Dr. Da Luo from Sun Yat-Sen University in China, is an open access and peer-reviewed journal publishing original research papers relevant to genomics and genetics in legume plants. It is committed to serving for legume genomics and genetics, especially featuring innovative research findings in the basic and applied fields of structural genomics, functional genomics, proteomics, epigenomics within the field of Legume sciences, as well as legume genetics from the molecular level to whole plant level.  相似文献   

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Genomics and Applied Biology (GAB) (ISSN1925-1602) is an international open access and peer review journal, containing original research papers, involving in the structural genomics, functional genomics, comparative  相似文献   

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Anthocyanins from blackberries are natural dietary pigments. The aim of this study was to investigate the occurrence of anthocyanins in fruits of wild Norwegian blackberries and three blackberry ( Rubus fruticosus L.) cultivars and to report the complete identification of cyanidin 3-O-β-(6″-(3-hydroxy-3-methylglutaroyl)glucopyranoside), 5. This new pigment is most probably the same pigment that has previously been reported to occur in various blackberry samples as cyanidin 3-dioxalylglucoside. All of the examined blackberry samples contained in similar relative proportions the 3-glucoside (1), 3-rutinoside (2), 3-xyloside (3), and 3-O-β-(6″-malonylglucoside) (4) of cyanidin and 5. The absolute amounts of 1-5 in the wild Norwegian blackberries were 249, 18, 10, 24, and 22 mg of cyanidin 3-glucoside equivalents/100 g of fresh weight, respectively.  相似文献   

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Soils were collected from 2-year (2-y) and 3-year (3-y) old red-pine seedling plots in two tree nurseries, Hayward in the north and Wilson in the southwestern part of Wisconsin State respectively, and equilibrated with 0.01 M Ca(NO3)2 for soil solution Zn and Mn (solu-Zn and Mn), and with 0.01 M Ca(NO3)2+0.005 M EDTA for soil adsorbed Zn and Mn (ad-Zn and Mn). Buffering capacity of soil Zn and Mn (b-Zn and Mn) was obtained from the ratio of ad-Zn and Mn to the solu-Zn and Mn. The concerned traces in pine seedling needles (ndls), stems(sts) and roots (rts) were simultaneously measured.  相似文献   

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The present study was designed to compare surface plasmon resonance (SPR) biosensor, enzyme-linked immunosorbent assay (ELISA), and ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) methods for the analysis of Nε-(carboxymethyl)lysine (CML) in glucose-bovine serum albumin (BSA) model systems and to investigate the possible inhibitory effect of selected compounds (α-tocopherol, ferulic acid, rutin, thiamin, thiamin monophosphate, and thiamin pyrophosphate) on CML formation. The reported levels of CML detected were dependent upon the method of analysis employed. The highest reported concentrations were obtained with the SPR biosensor, whereas the lowest were found by ELISA. However, a high correlation was observed between these two immunochemical procedures. CML concentrations were dependent upon the type and concentration of the candidate CML inhibitor. All inhibitory compounds investigated, with the exception of α-tocopherol, decreased the level of CML formation in the glucose-BSA system.  相似文献   

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The present study investigated the potentials of ionic liquids (ILs) containing aromatic rings in extracting and enriching n-3 polyunsaturated compounds. The relationship between extraction efficiency, selectivity, and structure of ILs was studied and elucidated. Ionic liquids containing aromatic rings such as the N,N'-dialkylimidazolium and N-alkylpyridinium are found to selectively extract and enrich n-3 polyunsaturated compounds. The IL extraction process reached equilibrium relatively quickly (<30 min), and the extraction efficiency can be further enhanced by increasing the volume ratio of IL to solvent, addition of silver tetrafluoroborate, and usage of double bond containing solvents such as 1-hexene as stripping solvent. At optimal conditions, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim]PF(6) and 1-butyl-3-methylpyridinium dicyanamide [BuMePyr]DCN had increased extraction capabilities of n-3 polyunsaturated fatty acids (PUFA) (16.19%) and n-3 polyunsaturated fatty acid ethyl esters (PUFAEE) (144.54%), respectively. Multiple-step reverse extraction whereby n-3 PUFAs were first enriched through IL/hexane extraction followed by addition of fresh hexane repeatedly up to three times to the IL phase to desorb the saturated FAs resulted in a higher purity of n-3 PUFAs. Following this reverse extraction operation, the purity of n-3 PUFA and n-3 PUFAEE in the IL phase increased from the initial 15.88 to 38% (step 1) and further to 45% (step 3) and from the initial 72.56 to 82% (step 1) and further to 89% (step 3), respectively. The results from this study strongly suggested the correlation of n-3 PUFA extraction with aromatic/delocalized cation structure of ILs, which provides the basis for future research in designing novel ILs task-specified for efficient long-chain PUFA concentration.  相似文献   

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Dry bean yields (Phaseolus vulgaris L.) were raised to similar levels as the topsoil by manure application to eroded or leveled Portneuf silt loam soil (coarse‐silty mixed mesic Durixerollic Calciorthid). Only soil organic matter and zinc (Zn) content of leaf tissue were correlated with improved yields. Manure application increased mycorrhizal colonization and Zn uptake in pot experiments with dry bean which would explain the increased yields in the field. A field study was conducted to see if similar effects of manure and mycorrhizal colonization could be observed in field grown spring wheat (Triticum aestivum L.) and sweet corn (Zea mays L.). This study was conducted on existing experiments established in the spring of 1991 at the USDA‐ARS farm in Kimberly, Idaho, to study crop rotation/organic matter amendment treatments on exposed subsoils and focused on mycorrhizal colonization as related to topsoils and subsoils treated with conventional fertilizer (untreated) or dairy manure. Mycorrhizal root colonization was higher with untreated than with manure‐treated wheat and sweet corn. Root colonization was also higher in subsoil than in topsoil for wheat, but there were no differences between soils for sweet corn. Shoot Zn and manganese (Mn) concentrations generally increased with increased root colonization for both species (except between soils with corn Mn contents). Wheat shoot potassium (K) concentration was increased by manure application, but the affect declined with time, was the opposite of colonization and was not observed with sweet com. Phosphorus (P), calcium (Ca), magnesium (Mg), iron (Fe), and copper (Cu) concentrations either were not influenced or were erratically affected by mycorrhizal colonization. Yields of wheat were highest for manure‐treated subsoil and topsoil compared to untreated soils. Mycorrhizal colonization was different between conventional and manure‐treated soils and between topsoil and subsoil and these differences increased Zn and Mn uptake, but they did not explain the improvement in wheat yields obtained with manure application.  相似文献   

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To evaluate the interaction between anionic species when they were adsorbed on variable charge soils, we measured the adsorption of NO3 - and SO4 2- on. an Andisol equilibrated with a mixture of KNO3 and K2SO4 solutions. The amount of NO3 - adsorption declined with the increase in the concentration of SO4 2-. On the other hand, the amount of SO4 2- adsorption increased with the increase in the concentration of NO3 -. These phenomena can not be explained by the simple “exchange theory” or the “Three-plane model” unless surface complexation is associated with the changes in the electrical potential of the surface. Therefore, in order to explain the phenomena by using the “Four-plane model” with surface complexation, a new equation was derived for the Diffuse Double Layer (DDL) charge from the “main equation of DDL theory” (equation of electrical potential in DDL) instead of the “Gouy-Chapman equation,” which can be used only for single symmetric electrolytes but nor for a mixture. By introducing the new equation to the computer program for analyzing the Four-plane model, the interaction between anionic species adsorbed on Andisols could be explained well. It was considered that SO4 2- acted as a regulator for the ionic concentration, osmotic pressure and pH of the soil solution, and consequently, these factors affected the vertical distribution and mobility of anionic species and also the mobility of counter-ions in Andisols.  相似文献   

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OBJECTIVES: To determine whether weight problems in children (overweight, obesity and overweight or obesity) were related to deprivation indices when attributed only according to electoral ward of the school attended. To determine whether children with weight problems were more likely to be found in some wards rather than others, and to compare the distribution for boys and girls. DESIGN: Retrospective, cross-sectional, observational study. SETTING: One hundred and six primary schools from all parts of Liverpool city. SUBJECTS: Five cohorts of 9-10-year-old children between 1998 and 2003. Main outcome measures: Body mass index (BMI) for each child to estimate proportions overweight, obese and overweight or obese according to international criteria. RESULTS: Between January 1998 and March 2003, the heights and weights of 7902 boys and 7514 girls were measured and BMI calculated. The prevalence of boys and girls categorised as overweight or obese was very high (1620, 20.6% and 1909, 25.7%, respectively). Prevalence was not related to deprivation and varied between wards only for the girls; some wards had very different prevalence rates for boys and girls (Picton: 59 boys, 23.4%; 106 girls, 36.6%). The most deprived ward did not have a remarkable prevalence of overweight or obesity (Speke: 32 boys, 15.3%; 40 girls, 19.8%). CONCLUSIONS: Obesity is a major problem and requires urgent action but targeting intervention on the basis of administrative areas may be very wasteful. Different factors seem to lead to obesity in boys and girls, and attention should be paid to the role of the physical environment.  相似文献   

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Adulteration of sulfited strawberry and raspberry purées by apple is a commercial problem. Strawberry (n = 31) and raspberry (n = 30) purées were prepared from Irish-grown fruit and adulterated at levels of 10-75% w/w using cooking apples. Visible and near-infrared transflectance spectra were recorded using a 0.1 mm sample thickness. Classification and quantification models were developed using raw and scatter-corrected and/or derivatized spectral data. Classification as pure strawberry or raspberry was attempted using soft independent modeling of class analogy. The best models used spectral data in the wavelength ranges 400-1098 nm (strawberry) and 750-1098 nm (raspberry) and produced total correct classification rates of 75% (strawberry) and 95% (raspberry). Quantification of apple content was performed using partial least-squares regression. Lowest predictive errors obtained were 11.3% (raspberry) and 9.0% (strawberry). These results were obtained using spectral data in the wavelength ranges 400-1880 and 1100-1880 nm, respectively. These results suggest minimum detection levels of apple in soft fruit purées of approximately 25 and 20% w/w for raspberry and strawberry, respectively.  相似文献   

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OBJECTIVE: The aim of the study was to investigate the relative importance of personal and social environmental predictors of the consumption of fruit, high-fat snacks and breakfast. DESIGN: A school-based cross-sectional survey. Data were collected through written questionnaires. SETTING: Students from eight schools in the southern part of The Netherlands. SUBJECTS: Six hundred and one students from preparatory secondary vocational education schools. RESULTS: About a quarter of the variation in actual behaviours and intentions to change the behaviours could be explained. Stepwise multiple regression analysis revealed that, for all three behaviours, higher intention to change was especially associated with a more positive attitude and subjective norm, and higher intentions to increase fruit intake with more positive self-efficacy expectations. With regard to actual consumption, a more positive attitude towards eating fruit was the only significant correlate of a higher consumption of fruit. A more positive attitude towards eating high-fat snacks, perceived lower intake of the mother, and higher food availability and accessibility were associated with consumption of high-fat snacks, and a more positive attitude to breakfast more frequently was associated with more frequent breakfast consumption. CONCLUSION: The results indicate that adolescents' attitudes are the most important determinants of different health-related eating behaviours and intentions to change. Interventions promoting a healthy diet for adolescents should include creative strategies to achieve positive associations with healthy dietary changes.  相似文献   

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