Construction and Characterization of Vitreoscilla Hemoglobin (VHb) with Enhanced Peroxidase Activity for Efficient Degradation of Textile Dye

( Zi Dong Zhang ),( Wei Li ),( Hai Chao Li ),( Jing Zhangi ),( Yue Bin Zhang ),( Yu Feng Cao ),( Jian Zhang Ma ),( Zheng Qiang Li ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.9

Pollution resulting from the discharge of textile dyes into water systems has become a major global concern. Because peroxidases are known for their ability to decolorize and detoxify textile dyes, the peroxidase activity of Vitreoscilla hemoglobin (VHb) has recently been studied. It is found that VHb and variants of this enzyme show great promise for enzymatic decolorization of dyes and may play a role in achieving their successful removal from industrial wastewater. The level of VHb peroxidase activity correlates with two amino acid residues present within the conserved distal pocket, at positions 53 and 54. In this work, sitedirected mutagenesis of these residues was performed and resulted in improved VHb peroxidase activity. The double mutant, Q53H/P54C, shows the highest dye decolorization and removal efficiency, with 70% removal efficiency within 5 min. UV spectral studies of Q53H/P54C reveals a more compact structure and an altered porphyrin environment (λSoret = 413 nm) relative to that of wild-type VHb (λSoret = 406), and differential scanning calorimetry data indicate that the VHb variant protein structure is more stable. In addition, circular dichroism spectroscopic studies indicate that this variant’s increased protein structural stability is due to an increase in helical structure, as deduced from the melting temperature, which is higher than 90°C. Therefore, the VHb variant Q53H/P54C shows promise as an excellent peroxidase, with excellent dye decolorization activity and a more stable structure than wild-type VHb under high-temperature conditions.

Tumor-Derived Transforming Growth Factor-β is Critical for Tumor Progression and Evasion from Immune Surveillance

Li, Zheng,Zhang, Li-Juan,Zhang, Hong-Ru,Tian, Gao-Fei,Tian, Jun,Mao, Xiao-Li,Jia, Zheng-Hu,Meng, Zi-Yu,Zhao, Li-Qing,Yin, Zhi-Nan,Wu, Zhen-Zhou Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.13

Tumors have evolved numerous mechanisms by which they can escape from immune surveillance. One of these is to produce immunosuppressive cytokines. Transforming growth factor-${\beta}$(TGF-${\beta}$) is a pleiotropic cytokine with a crucial function in mediating immune suppression, especially in the tumor microenvironment. TGF-${\beta}$ produced by T cells has been demonstrated as an important factor for suppressing antitumor immune responses, but the role of tumor-derived TGF-${\beta}$ in this process is poorly understood. In this study, we demonstrated that knockdown of tumor-derived TGF-${\beta}$ using shRNA resulted in dramatically reduced tumor size, slowing tumor formation, prolonging survival rate of tumor-bearing mice and inhibiting metastasis. We revealed possible underlying mechanisms as reducing the number of myeloid-derived suppressor cells (MDSC) and $CD4^+Foxp3^+$ Treg cells, and consequently enhanced IFN-${\gamma}$ production by CTLs. Knockdown of tumor-derived TGF-${\beta}$ also significantly reduced the conversion of na$\ddot{i}$ve $CD4^+$ T cells into Treg cells in vitro. Finally, we found that knockdown of TGF-${\beta}$ suppressed cell migration, but did not change the proliferation and apoptosis of tumor cells in vitro. In summary, our study provided evidence that tumor-derived TGF-${\beta}$ is a critical factor for tumor progression and evasion of immune surveillance, and blocking tumor-derived TGF-${\beta}$ may serve as a potential therapeutic approach for cancer.

Synthesisof Fructose Laurate Esters Catalyzed by a CALB-displaying Pichia pastoris Whole-cell Biocatalyst in a Non-aqueous System

Zi Jin,Shuli Liang,Xiuqin Zhang,Shuangyan Han,Changqiong Ren,Ying Lin,Suiping Zheng 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2

Earlier studies on fructose laurate ester products have shown that recombinant Pichia pastoris displaying Candida antarctica lipase B (CALB) on the cell surface acts as an efficient whole-cell biocatalyst for sugar ester production from fructose and lauric acid in an organic solvent. The effects of various reaction factors, including solvent composition, substrate molar ratio, enzyme dose,temperature and water activity, on esterification catalyzed by the CALB-displaying P. pastoris whole-cell biocatalyst were examined in the present study. Under the preferred reaction conditions, specifically, 5 mL organic solvent mixture of 2-methyl-2-butanol/DMSO (20% v/v), 2 mmol fructose with a lauric acid to fructose molar ratio of 2:1, 0.3 g whole-cell biocatalyst (1,264 U/g dry cell) with an initial water activity of 0.11, 1.2 g 4Å molecular sieve, reaction temperature of 55oC and 200 rpm stirring speed, the fructose mono laurate ester yield was 78% (w/w). The CALBdisplaying P. pastoris whole-cell biocatalyst exhibited good operational stability, with an evident increase, rather than decrease, in relative activity after the continuous recover and reuse cycle. The relative activity of the biocatalyst remained 50% higher than that of the first batch, even following reuse for 15 batches. Our results collectively indicate that the CALB-displaying P. pastoris whole-cell biocatalyst may be potentially utilized in lieu of free or immobilized enzyme to effectively produce non-ionic surfactants such as fatty acid sugar esters, offering the significant advantages of cost-effectiveness, good operational stability and mild reaction conditions.

Pu-erh Tea Powder Preventive Effects on Cisplatin-Induced Liver Oxidative Damage in Wistar Rats

Zheng, Xiao-Nan,Wang, Xiao-Wen,Li, Li-Ya,Xu, Zi-Wei,Huang, Hsin-Yi,Zhao, Jin-Sheng,Zhang, Duo,Yin, Xu,Sheng, Jun,Tang, Jin-Tian Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.17

Background: Chemotherapy is one of the major means for control of malignancies, with cisplatin (CDDP) as one of the main agents, widely used for the treatment of various malignant solid tumors. However, prevention of hepatotoxicity from cisplatin is one of the urgent issues in cancer chemotherapy. In this study, we aimed to investigate the effects of pu-erh tea on hepatotoxicity through body weight and tissue antioxidant parameters like, liver coefficient, serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), malondialdehyde(MDA) and glutathione (GSH) levels, and light microscopic evaluation by histological findings. Materials and Methods: The rats were randomly divided into five groups: Control (n=10), cisplatin (3 mg/kg p.i., n=10), cisplatin+pu-erh (0.32 g/kg/day i.g., n=10), cisplatin+pu-erh (0.8 g/kg/day i.g., n=10) and cisplatin+pu-erh (1.6 g/kg/day i.g., n=10). Pu-erh tea powder was administrated for 31 consecutive days. The rats were sacrificed at the end on the second day after a single dose of cisplatin treatment for measuring indices. Results: Pu-erh tea powder exhibited a protective effect by decreasing MDA and GSH and increasing the SOD and GSH-PX levels and GSH-PX/MDA ratio in camparison with the control group. Besides, pu-erh tea was also able to alleviate the pathological damage to some extent. Conclusion: Pu-erh tea powder is protective against cisplatin-induced liver oxidative damages, especially at the medium dosage (0.8 g/kg/d).

A Method for Evaluation of the Quality of DNA Microarray Spots

Zhang, Bao,Ma, Wen-Li,Hu, Zi-You,Shi, Rong,Song, Yan-Bin,Zheng, Wen-Ling Korean Society for Biochemistry and Molecular Biol 2002 Journal of biochemistry and molecular biology Vol.35 No.5

To establish a method to evaluate the quality of the printed microarray and DNA fragments' immobilization. The target gene fragments that were made with the restriction display PCR (RD-PCR) technique were printed on a superamine modified glass slide, then immobilized with UV cross-linking and heat. This chip was hybridized with universal primers that were labeled with cy3-dUTP, as well as cDNA that was labeled with cy3-dCTP, as the conventional protocol. Most of the target gene fragments on the chip showed positive signals, but the negative control showed no signal, and vice versa. We established a method that enables an effective evaluation of the quality of the microarrays.

Risk Factors for Nodal Metastasis in cN0 Papillary Thyroid Microcarcinoma

Zhang, Li-Yang,Liu, Zi-Wen,Liu, Yue-Wu,Gao, Wei-Sheng,Zheng, Chao-Ji Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Background: Despite the majority of papillary thyroid microcarcinoma (PTMC) patients having an excellent prognosis, cervical lymph node metastases are common. The purpose of this study was to investigate the incidence and the predictive risk factors for occult central compartment lymph node metastasis (CLNM) in PTMC patients. Materials and Methods: 178 patients with clinically node-negative (cN0) PTMC undergoing prophylactic central compartment neck dissection in our hospital from January 2008 to Jun 2010 were enrolled. The relationship between CLNM and the clinical and pathological factors such as gender, age, tumor size, tumor number, tumor location, extracapsular spread (ECS), and coexistance of chronic lymphocytic thyroiditis was analyzed. Results: Occult CLNM was observed in 41% (73/178) of PTMC patients. Multivariate analysis showed that male gender, tumor size (${\geq}6mm$) and ECS were independent variables predictive of CLNM in PTMC patients. Conclusions: Male gender, tumor size (${\geq}6mm$) and ECS were risk factors of CLNM. We recommend a prophylactic central lymph node dissection (CLND) should be considered in PTMC patients with such risk factors.

ZNF217 is Overexpressed and Enhances Cell Migration and Invasion in Colorectal Carcinoma

Zhang, Zi-Chao,Zheng, Li-Qiang,Pan, Li-Jie,Guo, Jin-Xing,Yang, Guo-Shan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Background: To investigate the expression and clinical significance of zinc finger protein 217 (ZNF217) in human colorectal carcinoma (CRC). Materials and Methods: The expression of ZNF217 in 60 CRC tissues and matched tumor adjacent tissues, collected between January 2013 and June 2014, was assessed immunohistochemically. The relationship between the expression of ZNF217 and clinicopathlogical features was analyzed by Pearson chi-square test. In addition, siRNA was used to down-regulate the expression of ZNF217 in CRC cells. The effects of ZNF217 for cell migration and invasion were measured by wound healing assay and transwell assay, respectively. Results: The expression level of ZNF217 was significantly higher in CRC tissues than in tumor adjacent tissues (p<0.05), positively correlating with tumor size, lymphatic metastasis and advanced TNM stage (p<0.05). Down-regulation of ZNF217 in CRC cells could significantly suppress cell migration and invasion. Conclusions: ZNF217 is overexpressed in colorectal carcinoma tissues and is associated with tumor malignant clinicopathological features. ZNF217 may promote CRC progression by inducing cell migration and invasion.

A Method for Evaluation of the Quality of DNA Microarray Spots

Zhang, Bao,Ma, Wen-Li,Hu, Zi-You,Shi, Rong,Song, Yan-Bin,Zheng, Wen-Ling 한국생화학분자생물학회 2002 BMB Reports Vol.35 No.5

To establish a method to evaluate the quality of the printed microarray and DNA fragments' immobilization. The target gene fragments that were made with the restriction display PCR (RD-PCR) technique were printed on a superamine modified glass slide, then immobilized with UV cross-linking and heat. This chip was hybridized with universal primers that were labeled with cy3-dUTP, as well as cDNA that was labeled with cy3-dCTP, as the conventional protocol. Most of the target gene fragments on the chip showed positive signals, but the negative control showed no signal, and vice versa. We established a method that enables an effective evaluation of the quality of the microarrays.

Structural Characterization and Optical Properties of Sol-gel-derived Polycrystalline Pb(Zr0.35Ti0.65)O3 Thin Films

Fan Zhang,Rong-Jun Zhang,Zi YiWang,Yu-Xiang Zheng,Song-You Wang,Hai-Bin Zhao,Liang-Yao Chen,Xiao Bin Liu,An Quan Jiang 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.1

Polycrystalline Pb(Zr0.35Ti0.65)O3 thin films prepared on Pt/Ti/SiO2/Si substrate by using solgel technique were characterized by using X-ray diffraction (XRD) and atomic force microscopy (AFM). The optical properties of the films were investigated by using spectroscopic ellipsometry (SE) with a four-phase optical model, air/roughness layer/PZT layer/Pt layer in the spectral range of 300 - 800 nm. The optical band gap of the films calculated following the Tauc’s Law was smaller than that of an amorphous PZT thin film with some microcrystals existing on the surface. The result indicates that the quantum-size effect leads to an increase in band gap when the crystalline dimensions become very small.

Nonsingular Fast Terminal Sliding Mode Control Strategy for PMLSM Based on Disturbance Compensation

Li Zheng,Zhang Zi-Hao,Wang Jin-Song,Yan Zhi-Bang,Guo Xiao-Qiang,Sun He-Xu 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

To optimize the anti-interference performance and dynamic response ability of permanent magnet linear synchronous motor (PMLSM) and enhance the overall control performance of the system, the novel nonsingular fast terminal sliding mode controller (NFTSMC) based on disturbance compensation is proposed in this design. To enhance the response speed and stability of the controller, this design introduces the system state variable into the exponential reaching law to make the controller adaptively adjust with the change of the system state, which can reduce the chattering of the system and have a faster response speed. The extended sliding mode disturbance observer is designed to estimate the interference factors in the system, and the controller is feedforward compensated to further improve the anti-interference ability of the PMLSM system. Meanwhile, the control strategy is proved by the Lyapunov stability theory. Simulation and experiments show that the proposed control strategy has better dynamic response ability and anti-interference ability than the traditional NFTSMC.