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2,886 results on '"Ma, Jin-An"'

12. 酶解法制备核桃谷蛋白-1 ACE抑制肽的工艺优化Preparation of ACE inhibitory peptide from walnut glutelin-1 by enzymatic hydrolysis

Author

王静，马劲，朱柏佳，姚嘉仪，汪飞，杨雯静，冯龙丹 WANG Jing, MA Jin, ZHU Baijia, YAO Jiayi, WANG Fei, YANG Wenjing, FENG Longdan

Subjects
核桃谷蛋白-1；ace抑制肽；蛋白酶；响应面试验, walnut glutelin-1, ace inhibitory peptide, protease, response surface methodology, Oils, fats, and waxes, TP670-699
Abstract

为获得优质的核桃蛋白血管紧张素转化酶（ACE）抑制肽的制备原料及优化其制备工艺，采用连续提取法从脱脂核桃粕中依次分离出清蛋白、球蛋白、醇溶蛋白、谷蛋白-1和谷蛋白-2 5种组分蛋白，测定5种组分蛋白的占比及ACE抑制率，以ACE抑制率最大的组分蛋白作为原料采用酶解法制备ACE抑制肽，在筛选出最适酶解用酶基础上，采用单因素试验与响应面试验优化酶解制备核桃蛋白ACE抑制肽的工艺。结果表明：5种组分蛋白中谷蛋白-1占比仅次于谷蛋白-2，且其ACE抑制率最高，以核桃谷蛋白-1为原料，在筛选出胃蛋白酶作为酶解用酶基础上，经工艺优化得到最优的酶解法制备核桃谷蛋白-1 ACE抑制肽的工艺条件为酶解温度46 ℃、酶解时间6 h、酶用量4.2%（以底物质量计）、酶解pH 1.6，在该条件下所得核桃谷蛋白-1 酶解液的ACE抑制率为（50.08±2.34）%。因此，核桃谷蛋白-1经胃蛋白酶酶解可生产ACE抑制活性较高的核桃多肽。In order to obtain high-quality raw materials for the preparation of angiotensin converting enzyme (ACE) inhibitory peptide from walnut protein and optimize its preparation process, five component proteins including albumin, globulin, prolamin, glutelin-1 and glutelin-2 were separated from defatted walnut meal using continuous extraction method in turn. The proportion and ACE inhibition rates of the five component proteins were determined.The component protein with the largest ACE inhibition rate was used as raw material to prepare ACE inhibitory peptide by enzymatic hydrolysis. On the basis of selecting the optimal enzyme, the enzymatic conditions for the preparation of walnut protein ACE inhibitory peptide were optimized by single factor experiment combined with response surface methodology.The results showed that the proportion of glutelin-1 in the five component proteins was second only to glutelin-2, and its ACE inhibition rate was the highest. With walnut glutelin-1 as raw material and pepsin as enzyme, the optimal enzymatic hydrolysis preparation conditions of walnut glutelin-1 ACE inhibitory peptide were obtained as follows: enzymolysis temperature 46 ℃, enzymolysis time 6 h, enzyme dosage 4.2%(based on the mass of substrate), and enzymolysis pH 1.6. The ACE inhibition rate of the enzymatic hydrolysate obtained under the optimal conditions was （50.08±2.34）%. Enzymatic hydrolysis of walnut glutelin-1 by pepsin can produce walnut polypeptides with higher ACE inhibitory activity.

Published
2024
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14. Stepped-up development of accelerator mass spectrometry method for the detection of 60Fe with the HI-13 tandem accelerator

Author

Zhang, Yang, Yan, Sheng-Quan, He, Ming, Zhao, Qing-Zhang, Zhang, Wen-Hui, Kan, Chao-Xin, Zhou, Jian-Ming, Li, Kang-Ning, Wang, Xiao-Fei, Liu, Jian-Cheng, Peng, Zhao-Hua, Liang, Zhuo, Li, Ai-Ling, Zheng, Jian, Fan, Qi-Wen, Li, Yun-Ju, Wang, You-Bao, Li, Zhi-Hong, Shen, Yang-Ping, Nan, Ding, Nan, Wei, Zhang, Yu-Qiang, Li, Jia-Ying-Hao, Tian, Jun-Wen, Hou, Jiang-Lin, Guo, Chang-Xin, Zhang, Zhi-Cheng, Zhu, Ming-Hao, Chen, Yu-Wen, Jiang, Yu-Chen, Tian, Tao, Ma, Jin-Long, Liu, Yi-Hui, Dong, Jing-Yu, Liu, Run-Long, Ma, Mei-Yue-Nan, Chen, Yong-Shou, Liu, Wei-Ping, and Guo, Bing

Published
2024
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16. Mitochondrial respiration reduces exposure of the nucleus to oxygen.

Author

Mori, Mateus, Penjweini, Rozhin, Ma, Jin, Alspaugh, Greg, Andreoni, Alessio, Kim, Young-Chae, Wang, Ping-Yuan, Knutson, Jay, and Hwang, Paul

Subjects
classification: cell biology, hypoxia, metabolism, mitochondria, nucleus, oxygen, respiration, Oxygen, Mitochondria, Respiration, Electron Transport Complex IV, Cell Nucleus, Oxygen Consumption, Cell Respiration
Abstract

The endosymbiotic theory posits that ancient eukaryotic cells engulfed O2-consuming prokaryotes, which protected them against O2 toxicity. Previous studies have shown that cells lacking cytochrome c oxidase (COX), required for respiration, have increased DNA damage and reduced proliferation, which could be improved by reducing O2 exposure. With recently developed fluorescence lifetime microscopy-based probes demonstrating that the mitochondrion has lower [O2] than the cytosol, we hypothesized that the perinuclear distribution of mitochondria in cells may create a barrier for O2 to access the nuclear core, potentially affecting cellular physiology and maintaining genomic integrity. To test this hypothesis, we utilized myoglobin-mCherry fluorescence lifetime microscopy O2 sensors without subcellular targeting (cytosol) or with targeting to the mitochondrion or nucleus for measuring their localized O2 homeostasis. Our results showed that, similar to the mitochondria, the nuclear [O2] was reduced by ∼20 to 40% compared with the cytosol under imposed O2 levels of ∼0.5 to 18.6%. Pharmacologically inhibiting respiration increased nuclear O2 levels, and reconstituting O2 consumption by COX reversed this increase. Similarly, genetic disruption of respiration by deleting SCO2, a gene essential for COX assembly, or restoring COX activity in SCO2-/- cells by transducing with SCO2 cDNA replicated these changes in nuclear O2 levels. The results were further supported by the expression of genes known to be affected by cellular O2 availability. Our study reveals the potential for dynamic regulation of nuclear O2 levels by mitochondrial respiratory activity, which in turn could affect oxidative stress and cellular processes such as neurodegeneration and aging.

Published
2023

20. The Effects of Icon Characteristics and Metaphors on the Recognition of Icons by Students With Different Knowledge Structures

Author

Zhao Xin, Ma Jin, Wu Guo Chao, and Zhang Qing Qing

Subjects
Mobile phone interface, knowledge difference, icon design, icon characteristics, icon metaphors, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Icons are widely used to communicate information in graphical user interfaces, and it is essential for designers to understand how users recognize and interpret them. This study investigates the impact of university students’ knowledge structures on icon usability. It examines the effects of icon metaphors (appearance, symbolic, relational, arbitrary) and icon characteristics (concreteness, abstractness) on icon recognition. One hundred participants from the liberal arts and sciences were tested (N =50). The test parameters included form recognition rate, functional accuracy rate, and response time. The results indicated that university students’ knowledge structures influenced the recognition of icon characteristics, with liberal arts students preferring concrete icons and science students preferring abstract icons. However, differences in knowledge structure had no significant effect on icon metaphor recognition. Furthermore, the liberal arts and science students showed some differences in recognizing specific combinations of icon characteristics and metaphors. These findings suggest that icon characteristics are influenced by knowledge structure, whereas metaphor recognition is more dependent on cultural structure. Specific combinations of icon characteristics and metaphors can significantly improve icon usability. The implications of these findings suggest new ways for graphical interface icons to enhance usability.

Published
2024
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