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991.
992.
Fresh Mashui orange samples were pretreated with microwave digestion using an HNO3-H2O2 system. The levels of Mg, K, Ca, Fe, Mn, Cu, Zn, As, Cd, and Pb in the seeds, pulp, and peel were then determined using inductively coupled plasma mass spectrometry (ICP-MS) combined with collision cell technology (CCT) and kinetic energy discrimination (KED). The standard curve coefficient of determinations of the ten tested elements were between 0.9995 and 0.9999. The instrument detection limit was between 0.112 ng/L and 3.05 ng/mL. The method detection limit was between 0.0281 and 763 ng/g. The average recovery rate was between 85.0 and 117%. The current results showed that Mashui oranges are rich in three elements, namely Mg, K, and Ca. The concentrations of K and Ca were significantly higher than that of Mg in the peel. The content of K was the highest in the seeds. Fe, Mn, Cu, and Zn had the second highest concentrations, and Fe was the highest in the seeds, while Cu was the lowest in the peel. As, Cd, and Pb (hazardous elements) had the lowest concentrations of all the tested elements. 相似文献
993.
994.
Liu Yang Lingyang Xu Yang Zhou Mei Liu Lei Wang James W. Kijas Hongping Zhang Li Li George E. Liu 《Genomics》2018,110(3):143-148
Copy number variation (CNV) represents a major source of genomic variation. We investigated the diversity of CNV distribution using SNP array data collected from a comprehensive collection of geographically dispersed sheep breeds. We identified 24,558 putative CNVs, which can be merged into 619 CNV regions, spanning 197 Mb of total length and corresponding to ~ 6.9% of the sheep genome. Our results reveal a population differentiation in CNV between different geographical areas, including Africa, America, Asia, Southwestern Asia, Central Europe, Northern Europe and Southwestern Europe. We observed clear distinctions in CNV prevalence between diverse groups, possibly reflecting the population history of different sheep breeds. We sought to determine the gene content of CNV, and found several important CNV-overlapping genes (BTG3, PTGS1 and PSPH) which were involved in fetal muscle development, prostaglandin (PG) synthesis, and bone color. Our study generates a comprehensive CNV map, which may contribute to genome annotation in sheep. 相似文献
995.
A Multistep, ATP-dependent Pathway for Assembly of Human Immunodeficiency Virus Capsids in a Cell-free System 总被引:14,自引:0,他引:14 下载免费PDF全文
Jaisri R. Lingappa Rebecca L. Hill Mei Lie Wong Ramanujan S. Hegde 《The Journal of cell biology》1997,136(3):567-581
To understand the mechanism by which human immunodeficiency virus type 1 (HIV) capsids are formed, we have reconstituted the assembly of immature HIV capsids de novo in a cell-free system. Capsid authenticity is established by multiple biochemical and morphologic criteria. Known features of the assembly process are closely reproduced, indicating the fidelity of the cell-free reaction. Assembly is separated into co- and posttranslational phases, and three independent posttranslational requirements are demonstrated: (a) ATP, (b) a detergent-sensitive host factor, and (c) a detergent-insensitive host subcellular fraction that can be depleted and reconstituted. Assembly appears to proceed by way of multiple intermediates whose conversion to completed capsids can be blocked by either ATP depletion or treatment with nondenaturing detergent. Specific subsets of these intermediates accumulate upon expression of various assembly-defective Gag mutants in the cell-free system, suggesting that each mutant is blocked at a particular step in assembly. Furthermore, the accumulation of complexes of similar sizes in cells expressing the corresponding mutants suggests that comparable intermediates may exist in vivo. From these data, we propose a multi-step pathway for the biogenesis of HIV capsids, in which the assembly process can be disrupted at a number of discrete points. 相似文献
996.
997.
Analysis of type 1 metallothionein cDNAs in Vicia faba 总被引:7,自引:0,他引:7
998.
胚胎鼠胃粘膜上皮细胞的原代培养 总被引:1,自引:0,他引:1
采用胰酶冷消化法对胚胎鼠胃粘膜上皮细胞进行了培养,细胞培养于含20%的胎牛血清的DMEM/F12的培养液中,种植24h后开始生长,3d长成片状,相差显微镜下观察90%的细胞具有上皮细胞特征。免疫细胞化学显示:(a)90%的细胞上皮角蛋白染色阳性;(b)90%的上皮细胞PAS染色阳性;(c)20%的上皮细胞琥珀酸脱氢酶(SDH)染色阳性。透射电镜可见微绒毛、连接复合物(紧密连接,桥粒)、丰富的糖原、线粒体。放射自显影结果表明:上皮细胞具有合成DNA的能力,而且在培养2d时增殖能力最强。本实验为研究胃粘膜的功能提供了较好的方法。 相似文献
999.
黑莓汁的理化特性及贮藏期营养成分的变化 总被引:11,自引:1,他引:10
对黑莓浓缩汁的理化特性及其营养成分变化进行研究,结果表明:pH3~4,波长511~514nm时,果汁色泽最佳;果汁抗氧化还原能力很弱,但具有很强的光和热的稳定性。0~4℃低温贮藏1年后,6种维生素的损失率都超过50%;含糖量损失407%;SOD活性和氨基酸含量分别损失10%和124%;含酸量略有增加 相似文献
1000.