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原子荧光和电感耦合等离子体质谱法在硒形态分析中的应用 总被引:1,自引:0,他引:1
硒是人体必需的微量元素之一,具有抗肿瘤、防衰老、防辐射和增强机体免疫力等多种功能。近年来,随着人们生活水平的不断提高,各种各样的富硒产品及富硒保健品走进了我们的生活,硒的形态测定越来越受到人们广泛的关注。本文对目前主要检测硒形态的两种方法—原子荧光法(AFS)和电感耦合等离子质体谱法(ICP-MS)在食品、水果蔬菜、富硒保健品、生物样品等方面的应用进行了综述。 相似文献
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采用微波水解、HPLC-HG-AFS法测定了硒蛋白粉、硒蛋白片、肽粉、富硒原料等19种硒产品中的总硒、硒代氨基酸和亚硒酸根离子[Se(IV)],分析了硒代氨基酸、Se(IV)和其他形态硒占总硒的百分比及不同形态硒代氨基酸的组成比例。以此为依据,将硒产品分为硒蛋白型、单一硒代氨基酸型、其它形态硒型及有机无机硒混合型。根据DBS42/002-2014规定建立了富有机硒产品评分模式,其中18种为富有机硒产品;根据适硒地区母乳中硒代氨基酸的组成比例提出了硒代氨基酸的化学评分模式,评分结果显示13种以蛋白态硒为主的硒产品中硒代氨基酸的组成比例均与母乳相差甚远,不利于人体平衡吸收利用,其中10种SeMet含量远远超过人体所需,SeCys_2为限制硒代氨基酸。该评分模式的建立对硒产品的开发具有指导意义。 相似文献
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恩施州天然硒资源特征及其开发利用研究进展 总被引:1,自引:0,他引:1
《生物技术进展》2017,(5)
硒是人和动物所必需的微量元素,也是恩施的优势特色资源。从恩施州的硒资源特征、开发利用情况以及对硒研究的问题和建议两方面,探讨了恩施硒资源的研究现状,并对其未来对硒资源的开发利用方向进行了展望,以期为后续的硒相关研究以及富硒产品的产业开发提供参考和指导。 相似文献
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中国典型高硒区硒的环境地球化学研究进展 总被引:1,自引:0,他引:1
《生物技术进展》2017,(5)
硒是人体和动物必需的微量元素,但其营养性的阈值范围较窄,已引起了不同领域研究者的广泛关注。综述了近20年来我国典型高硒区——湖北恩施富硒岩石与土壤中硒的分布与形态、硒的赋存状态、硒的迁移转化规律、硒的生物可利用性与人体健康风险、微生物与硒相互作用等硒的环境地球化学过程与循环规律,以及硒的同位素地球化学等方面的重要研究进展,并对硒的环境地球化学未来的研究方向进行了展望。 相似文献
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基于生态位理论的富硒土壤资源开发利用适宜性评价及分区方法 总被引:2,自引:0,他引:2
实施乡村振兴战略,产业兴旺是关键。立足区域富硒土壤资源禀赋优势,发展富硒农业特色经济,是振兴乡村产业的一条有效途径。以多维超体积生态位理论为指导,以区域富硒土壤资源禀赋和富硒农业发展要求为基础,从土壤自身条件、土地利用和生态保护3个方面明确了富硒土壤资源开发利用的主导因素、区位因素、限制因素;选择土壤硒含量、土壤有机质含量、地形坡度、土地利用类型、土地综合污染指数、生态保护建设等6个关键因子,构建了富硒土壤资源开发利用生态位适宜性评价指标体系;利用生态位适宜性评价相关模型,探讨了生态位适宜性单一指数和综合指数的计算方法;结合土壤利用改良分区、土壤利用功能分区、富硒农业生产分区等,分析了区域富硒土壤资源开发利用适宜性分区问题。研究可为富硒土壤资源开发利用适宜性评价提供科学可行的思路与方法,对于促进区域富硒土壤资源科学合理利用、实现富硒农业产业科学发展具有重要的指导意义和现实意义。 相似文献
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正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases 相似文献
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Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme
responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare
the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show
that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by
distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of
demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least
one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of
the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable
potent antiproliferative synthetic drugs. 相似文献
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The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle. 相似文献
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H.-R. GREGORIUS 《Biological journal of the Linnean Society. Linnean Society of London》1984,23(2-3):157-165
For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment. 相似文献
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment. 相似文献
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Å. Berg 《Bird Study》2013,60(2):153-165
CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden. Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden. Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified. Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds. Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed. 相似文献
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This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized. 相似文献