Refolding with Simultaneous Purification of Recombinant Core Streptavidin Using Single-step High-performance Hydrophobic Interaction Chromatography

Siyao Wang,Yuejuan Zhang,Dong Gao,Jing Zi,Wenpeng Wang,Nianzhe Zhang,Yi Wan,Lili Wang 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.4

Streptavidin has applied to many areas including detection, purification, labeling, crosslinking and immobilization resulting in a high demand on its production. In this study, we report a method for preparation of recombinant core streptavidin (cSAV) protein using highperformance hydrophobic interaction chromatography (HPHIC). Firstly the cSAV was successfully cloned and expressed in Escherichia coli as inclusion bodies. A bifunctional stationary phase mainly working as HIC mode accompanied by weak anion exchange chromatography (WAX) was prepared using β-phenylethylamine (PEA) as a ligand. The denatured cSAV was then refolded and simultaneously purified by PEA hydrophobic interaction chromatography (PEA-HIC). The mass recovery and purity of cSAV by single-step were 30.2% and 98%, respectively. The bioactivity was determined to be 13.2 U/mg by biotin binding capacity assay. This method provides a new possibility for fast separation with simultaneous renaturation of cSAV.

Numerical study on particle deposition in rough channels with large-scale irregular roughness

Wenpeng Hong,Xin Wang 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.7

We studied particle deposition in rough channels, using the W-M fractal function to characterize a largescale irregular surface with a root-mean-square roughness of 0.5mm. The flow was numerically investigated by Reynolds stress model, and the particles were tracked by a Lagrangian particle model. An analysis of the flow field in a rough channel shows that the roughness enhances the max flow velocity and the pressure drop in the channel. It induces several eddies in the concave of the rough surface. We also compared particle deposition in a rough channel with particle deposition in a smooth channel. This comparison shows that the roughness significantly enhances the particle deposition of small particles, but the enhancement decreases with the increase of particle size. Moreover, the particle deposition ratio decreases with increasing flow velocity.

An Investigation of Surface Tracking Characteristics and Factors Influencing Epoxy Resin Pouring Insulation for Dry-type Reactors

Yongqiang Wang,Han Liu,Wenpeng Li,Renjie Ding 한국고분자학회 2019 Macromolecular Research Vol.27 No.3

This study aimed to understand the deterioration mechanisms of epoxy resin pouring insulation for outdoor dry-type reactors under the effect of long-term surface tracking discharge. Epoxy resin insulation boards similar to the main insulation composition of the dry-type reactor were poured as the experimental material. A tracking experimental platform of insulation materials was built using an inclined plate method. The tracking discharge characteristics and surface erosion of the insulation materials were measured and analyzed. The characteristics of partial discharge, erosion, hydrophobicity and surface roughness were measured experimentally. Surface morphology, three-dimensional morphology and Fourier infrared images at different stages during erosion of the epoxy resin insulation material were analyzed. The effect of glass fiber content on the tracking resistance to erosion was characterized. The results show that the tracking process of epoxy resin insulation material experienced initiation, stability, development and outbreak periods. The flashover discharge corresponding to the development period was the main reason for the carbonization of the insulating material. During the tracking process, with a change in surface topography and formation of surface products, the surface roughness of the material generally increased along with the surface roughness which rose fastest during the discharge outbreak period. The changes in the surface morphology and three-dimensional morphology of the epoxy resin material constitute the basis for assessing the condition of the insulation surface and development of the erosion. The discharge capacity of epoxy resin generally shows an exponential increase. Adding 20 wt% of glass fibers that are evenly distributed and have reduced exposure can improve the tracking resistance of epoxy resin insulation materials.

Cactus-like double-shell structured SiO2@TiO2 microspheres: Fabrication, electrorheological performances and microwave absorption

Xuqiang Ji,Wenling Zhang,Wenpeng Ji,Xiaoxia Wan,Yutian Wang,Li Deng,Jingquan Liu 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.56 No.-

The cactus-like double-shell structured SiO2@TiO2 microspheres (CDS SiO2@TiO2 microspheres) withhigh dielectric properties were successfully fabricated and utilized as high-performance electrorheological(ER)fluids and microwave absorbing materials. The SiO2 nanospheres with average diametersof 190 nm were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS), and used as the core forthefirst coating layer of TiO2 achieved by sol-gel method. Thefinal cactus-like TiO2 layer was prepared viaa hydrothermal method. The morphology of the resultant samples was characterized via transmissionelectron microscopy (TEM), scanning electron microscopy (SEM) and scanning transmission electronmicroscopy (STEM). This novel CDS SiO2@TiO2 microspheres based suspension exhibited improved ERproperties compared to conventional bare SiO2 spheres.

Elucidating Bottlenecks to the Efficient Preparation of AB₅-Hexamer Mucosal Adjuvant Protein LTm by Genetic Engineering

( Di Liu ),( Fabiao Hu ),( Wenpeng Wang ),( Dong Wu ),( Xiujuan He ),( Wenyun Zheng ),( Haipeng Liu ),( Xingyuan Ma ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

Escherichia coli heat-labile enterotoxin (LT) and its non-toxic mutant (LTm) are well-known powerful mucosal adjuvants and immunogens. However, the yields of these adjuvants from genetically engineered strains remain at extremely low levels, thereby hindering their extensive application in fundamental and clinical research. Therefore, efficient production of these adjuvant proteins from genetically engineered microbes is a huge challenge in the field of molecular biology. In order to explore the expression bottlenecks of LTm in E. coli, we constructed a series of recombinant plasmids based on various considerations and gene expression strategies. After comparing the protein expression among strains containing different recombinant plasmids, the signal sequence was found to be critical for the expression of LTm and its subunits. When the signal sequence was present, the strong hydrophobicity and instability of this amino acid sequence greatly restricted the generation of subunits. However, when the signal sequence was removed, abundantly expressed subunits formed inactive inclusion bodies that could not be assembled into the hexameric native form, although the inclusion body subunits could be refolded and the biological activity recovered in vitro. Therefore, the dilemma choice of signal sequence formed bottlenecks in the expression of LTm. These results reveal the expression bottlenecks of LTm, provide guidance for the preparation of LTm and its subunits, and certainly help to promote efficient preparation of this mucosal adjuvant protein.

Multilevel Pedicle Subtraction Osteotomy for Correction of Thoracolumbar Kyphosis in Ankylosing Spondylitis: Clinical Effect and Biomechanical Evaluation

Xin Lv,Yelidana Nuertai,Qiwei Wang,Di Zhang,Xumin Hu,Jiabao Liu,Ziliang Zeng,Renyuan Huang,Zhihao Huang,Qiancheng Zhao,Wenpeng Li,Zhilei Zhang,Liangbin Gao 대한척추신경외과학회 2024 Neurospine Vol.21 No.1

Objective: To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Methods: Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Results: Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Conclusion: Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.