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- 저자 : ( Juanjuan Shi ) (검색결과 3 건)
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Yang Hu,Shanyi Shi,Lu Lu,Chunying Teng,Sumei Yu,Xin Wang,Min Yu,Jinsong Liang,Juanjuan Qu 한국고분자학회 2017 Macromolecular Research Vol.25 No.3
Excessive reactive oxygen species is implicated in the etiology and pathology of many acute and chronic diseases. Selenium acts as an antioxidant and stimulates the creation of more antioxidants. Selenizing modification polysaccharides potentiate the physiological and pharmacological activities of selenium and polysaccharide. In this study, Inonotus obliquus polysaccharide (IOP) extracted from cultured mycelia was modified into Se-IOP by HNO3- Na2SeO3 method. The characteristics and antioxidant activity of IOP and Se-IOP were comparatively investigated. The result showed that polysaccharide content of purified IOP was 98.9%. The selenium content of Se-IOP was 0.71 mg/g. Both IOP and Se-IOP were homogeneous polysaccharides with a molecular weight of 37.354 and 28.071 kDa, respectively depicted in high performance gel permeation chromatogram (HPGPC). Moreover, both IOP and Se- IOP were composed of Man, Glu, and Gal with a molar ratio of 7.7:32.6:23.3 and 8.3:32.1:22.7, respectively determined by high performance liquid chromatography (HPLC). The characteristic absorption peak of O-Se-O, Se=O and C-O-Se appeared at 1026.75, 772.82, and 652.29 cm-1 respectively in FT-IR spectrum of Se-IOP indicating the success of selenylation. NMR spectrum further confirmed the anomeric carbon signals and chemical shifts in IOP and Se-IOP. These variations induced by selenylation may lead to a higher antioxidant activity of Se-IOP on scavenging hydroxyl, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide radical than that of IOP. Furthermore, Se- IOP treatment could also reduce oxidant damage by decreasing the level of malondialdehyde (MDA) and increasing the activities of superoxidedismutase (SOD) and GSH-Px in mice.
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Overexpression of the potato StEPF2 gene confers enhanced drought tolerance in Arabidopsis
Yanli Wang,Tian Xie,Chunli Zhang,Juanjuan Li,Zhi Wang,Hongbing Li,Xiping Liu,Li-Na Yin,Shi-Wen Wang,Sui-Qi Zhang,Xiping Deng,Qingbo Ke 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.4
Epidermal patterning factor 2 (EPF2) is a negative regulator of stomatal development, and is essential for plant growth, development, and environmental stress responses. However, the role of EPF2 in potato (Solanum tuberosum) has not been investigated to date. Here, we cloned and characterized the potato EPF2-like gene (StEPF2). StEPF2 is predominantly intercellular space localized and its transcripts were rhythmically expressed, and showed the highest expression in apical unexpanded leaves. Expression of StEPF2 was markedly down-regulated in response to abscisic acid and sodium chloride treatments; however, upon the application of polyethylene glycol, the expression of StEPF2 peaked at 4 h and then decreased gradually. Overexpression of StEPF2 in Arabidopsis (OE) substantially reduced stomatal density and photosynthetic rate, but had little effects on plant growth. Under drought stress, OE lines maintained higher photosynthetic rates, photosystem II efficiency, and instantaneous water use efficiency than wild-type (WT) plants. Moreover, OE lines showed less water loss and hydrogen peroxide accumulation in detached leaves compared with WT plants. Thus, our results suggest that StEPF2 acts as a negative regulator of stomatal development in potato, indicating that the role of EPF2 is conserved across plant species. Overall, StEPF2 represents an important target for the development of drought-tolerant potato cultivars via genetic engineering.
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( Ning Yang ),( Zhenmin Ling ),( Liang Peng ),( Yanlai Liu ),( Pu Liu ),( Kai Zhang ),( Aman ),( Juanjuan Shi ),( Xiangkai Li ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.9
Fusarium oxysporum trypsin (FOT) is a fungal serine protease similar to mammal trypsin. The FOT could be successfully expressed in Pichiapastoris by engineering the natural propeptide APQEIPN. In this study, we constructed two recombinant enzymes with engineered amino acid sequences added to the N-terminus of FOT and expressed in P. pastoris. The N-terminal residues had various effects on the structural and functional properties of trypsin. The FOT, and the recombinants TE (with peptide YVEF) and TS (with peptide YV) displayed the same optimum temperature (40°C) and pH (8.0). However, the combinants TE and TS showed significantly increased thermal stability at 40°C and 50°C. Moreover, the combinants TE and TS also showed enhanced tolerance of alkaline pH conditions. Compared with those of wildtype FOT, the intramolecular hydrogen bonds and the cation π-interactions of the recombinants TE and TS were significantly increased. The recombinants TE and TS also had significantly increased catalytic efficiencies (referring to the specificity constant, k<sub>cat</sub>/K<sub>m</sub>), 1.75- fold and 1.23-fold than wild-type FOT. In silico modeling analysis uncovered that the introduction of the peptides YVEF and YV resulted in shorter distances between the substrate binding pocket (D174, G198, and G208) and catalytic triad (His42, Asp102, and Ser180), which would improve the electron transfer rate and catalytic efficiency. In addition, N-terminal residues modification described here may be a useful approach for improving the catalytic efficiencies and characteristics of other target enzymes.
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