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421 results on '"Jiang, Zedong"'

17. Effects of N-Terminal Non-catalytic Domains on Enzymatic Properties of the Alginate Lyase AlgL7 from Microbulbifer sp. ALW1

Author

HUANG Xiaoyi, LI Hebin, CHEN Yanhong, JIANG Zedong, NI Hui, LI Qingbiao, ZHU Yanbing,

Subjects
alginate lyase, carbohydrate-binding module, f5/8 type c domain, enzymatic properties, enzymatic hydrolysate, Food processing and manufacture, TP368-456
Abstract

In order to clarify the effect of the non-catalytic carbohydrate-binding module (CBM) and F5/8 type C domains on the enzymatic properties of AlgL7, an alginate lyase from Microbulbifer sp. ALW1, the full-length enzyme AlgL7 and two truncated enzymes: CD1 (catalytic domain) and CD2 (containing F5/8 type C domain and catalytic domain) were constructed and characterized. The results showed that the truncated enzyme CD2 exhibited higher specific activity, thermostability, Michaelis constant (Km), and maximum reaction velocity (Vmax) compared to the full-length AlgL7, indicating that the CBM domain played an important role in maintaining the substrate affinity of the enzyme, but reduced the catalytic activity, thermostability, and Vmax value the enzyme. Compared to the truncated enzyme CD1, CD2 exhibited higher specific activity, optimal reaction temperature, thermostability, Vmax, and Km, indicating that the F5/8 type C domain contributed to improve the enzymatic activity, optimum reaction temperature, thermostability, and Vmax, but reduced the substrate affinity of the enzyme. Using sodium alginate as the substrate, the specific activity of CD2 was 183.9 U/mg. The optimal reaction temperature and pH were 40 ℃ and 7.0, respectively. The Km and Vmax were 39.80 mg/mL and 2 000 U/mg, respectively. The major enzymatic hydrolysates were disaccharides and trisaccharides. This study promotes the understanding of the structure-activity relationship between the non-catalytic domains and the properties of alginate lyase, and lays a theoretical basis for using the non-catalytic domains to improve the catalytic properties of alginate lysate.

Published
2023
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24. In Vitro Pro-angiogenic Activity of Porphyran Prepared from Porphyra yezoensis in Human Umbilical Vein Endothelial Cells (HUVECs) Model

Author

FENG Fengzhen, ZHENG Mingjing, HONG Tao, LI Zhipeng, DU Xiping, ZHU Yanbing, NI Hui, JIANG Zedong

Subjects
porphyran, human umbilical vein endothelial cells, cell migration, pro-angiogenic activity, Food processing and manufacture, TP368-456
Abstract

In this study, the total sugar, protein, 3,6-anhydro galactose and sulfate contents, apparent molecular mass and monosaccharide composition of porphyran isolated from Porphyra yezoensis were analyzed. The pro-angiogenic activity and underlying mechanism of porphyran were further investigated using human umbilical vein endothelial cells (HUVECs) as an in vitro angiogenesis model. The effect of porphyran on the cell viability of HUVECs was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell adhesion and migration capacity were evaluated using cell adhesion and wound healing assays. The number of lumens formed by HUVECs was analyzed using in vitro tube formation assay. The expression levels of E-cadherin and N-cadherin in HUVECs were analyzed by Western Blotting, and the pro-angiogenic mechanism of porphyran in HUVECs was explored using specific inhibitors of mitogen-activated protein kinases (MAPKs) and vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitors. The results showed that porphyran contained (77.48 ± 2.62)% total sugar, (3.24 ± 0.58)% protein, and (20.30 ± 1.06)% 3,6-anhydrogalactose as well as (20.78 ± 3.31)% sulfate groups. The apparent molecular mass of porphyran was 39.81 kDa. Porphyran was mainly composed of galactose, 3,6-anhydrogalactose and sulfate groups, suggesting it to be a sulfated galactan. Furthermore, porphyran treatment in the concentration range of 0–200 μg/mL had no significant toxicity no HUVECs, but instead promote cell proliferation, adhesion, migration, and vascular network formation. Further studies demonstrated that porphyran exerted its pro-angiogenic effect primarily by mediating the down-regulation of E-cadherin expression and the up-regulation of N-cadherin expression through the c-Jun N-terminal kinase (JNK) MAPK and VEGF receptor signaling pathways. In conclusion, porphyran has pro-angiogenic potential, which will provide a scientific basis for the development of porphyran as a novel pro-angiogenic factor and the precision nutrition-guided deep processing and high-value utilization of the red seaweed P. yezoensis.

Published
2023
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39. Characteristics and mechanism of Ni2+and Cd2+adsorption by recovered perlite from agar extraction residue

Author

Wang, Juan, Zhu, Yanbing, Jiang, Zedong, Du, Xiping, Zheng, Mingjing, Li, Lijun, Ni, Hui, Wang, Yuanpeng, Li, Zhipeng, and Li, Qingbiao

Abstract

Ni2+and Cd2+in wastewater accumulated through the ecological chain and could jeopardize human health. Adsorption of Ni2+and Cd2+from wastewater using recovered perlite was an important way to solve the problem of resource utilization of solid waste from agar production. Our previous study confirmed that recovered perlite from agar extraction residue had better pore size and specific surface area than commercial perlite. However, the adsorption efficiency and adsorption mechanism of recovered perlite were the main factors limiting its adsorption application. The adsorption process of Ni2+and Cd2+by recovered perlite in aqueous solution was described by the pseudo-second-order kinetic equation, and the relevant adsorption mechanism was mainly chemisorption. Compared with commercial perlite, the adsorption removal rate of Ni2+and Cd2+by enzymatic recovered perlite could reach 92.9% and 89.2%, respectively, and were improved by 12.63% and 13.03%. Langmuir isothermal adsorption model could better describe the isothermal adsorption process of recovered perlite on heavy metal Ni2+and Cd2+, and the relevant adsorption mechanism was mainly monolayer adsorption. The X-ray photoelectron spectroscopy (XPS) results indicated that the decrease of Si–O Si2+hydroxyl coordination bond and the increase of C–Si bond might make the binding effect of recovered perlite with heavy metals stronger. The competitive adsorption of Ni2+and Cd2+by recovered perlite was still dominated by chemisorption and monolayer adsorption. This study was expected to provide a theoretical basis and technical support for the removal of Ni2+and Cd2+from wastewater using recovered perlite from seaweed residue.

Published
2024
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