Production of a Recombinant Laccase from Pichia pastoris and Biodegradation of Chlorpyrifos in a Laccase/Vanillin System

( Hui fang Xie ),( Qi Li ),( Min Min Wang ),( Lin Guo Zhao ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.6

The recombinant strain P. pastoris GS115-lccC was used to produce laccase with high activity. Factors influencing laccase expression, such as pH, methanol concentration, copper concentration, peptone concentration, shaker rotate speed, and medium volume were investigated. Under the optimal conditions, laccase activity reached 12,344 U/L on day 15. The recombinant enzyme was purified by precipitating and dialyzing to electrophoretic homogeneity, and was estimated to have a molecular mass of about 58 kDa. When guaiacol was the substrate, the laccase showed the highest activity at pH 5.0 and was stable when the pH was 4.5~6.0. The optimal temperature for the laccase to oxidize guaiacol was 60℃, but it was not stable at high temperature. The enzyme could remain stable at 30℃ for 5 days. The recombinant laccase was used to degrade chlorpyrifos in several laccase/mediator systems. Among three synthetic mediators (ABTS, HBT, VA) and three natural mediators (vanillin, 2,6-DMP, and guaiacol), vanillin showed the most enhancement on degradation of chlorpyrifos. Both laccase and vanillin were responsible for the degradation of chlorpyrifos. A higher dosage of vanillin may promote a higher level of degradation of chlorpyrifos, and the 2-step addition of vanillin led to 98% chlorpyrifos degradation. The degradation of chlorpyrifos was faster in the L/V system (kobs = 0.151) than that in the buffer solution (kobs = 0.028).

Estimation of load and resistance factors based on the fourth moment method

Zhao-Hui Lu,Yan-gang Zhao,Alfredo H-S. Ang 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.1

The load and resistance factors are generally obtained using the First Order Reliability Method (FORM), in which the design point should be determined and derivative-based iterations have to be used. In this paper, a simple method for estimating the load and resistance factors using the first four moments of the basic random variables is proposed and a simple formula for the target mean resistance is also proposed to avoid iteration computation. Unlike the currently used method, the load and resistance factors can be determined using the proposed method even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not need either the iterative computation of derivatives or any design points. Thus, the present method provides a more convenient and effective way to estimate the load and resistance factors in practical engineering. Numerical examples are presented to demonstrate the advantages of the proposed fourth moment method for determining the load and resistance factors.

Performance Analysis of Fixed-Burst-Length Optical Burst Switching Networks

Zhao Hui,Seung-Woo Seo 한국통신학회 2003 한국통신학회 학술대회 및 강연회 Vol.2003 No.4

Artificial control maturation of porcine oocyte by dibutyryl cyclicAMP

Zhao, Ming-Hui,Jin, Yong-Xun,Lee, Seul-Ki,Kim, Nam-Hyung,Cui, Xiang-Shun TaylorFrancis 2014 Animal cells and systems Vol.18 No.1

<P>In this study, we investigated the effects of various durations of dibutyryl cyclic AMP (dbcAMP) treatment on the in vitro maturation (IVM) and subsequent development of parthenogenetically activated embryos. Immature porcine oocytes were cultured with or without 1 mM dbcAMP during the first 20, 28, or 36 h of culture, and then incubated for an additional 24 h without dbcAMP. The expression of <I>Wee1B, Myt</I>, and <I>Cdc25B</I> and the level of maturation promoting factor (MPF) in metaphase II oocytes were analyzed by real-time PCR (qRT-PCR) and enzyme linked immunosorbent assay (ELISA), respectively. The distribution of actin microfilaments in oocytes was also assessed. Subsequently, apoptotic cells in blastocysts from each group were visualized by transferase-mediated dUTP nick-end labeling staining. Results showed that oocytes extruded the first polar body between 12 and 18 h after being released from dbcAMP. MPF activity in oocytes at 28 + 24 h and 36 + 24 h after dbcAMP treatment was higher than that in the control group. Significantly more blastocysts were present among embryos in 28 + 24 h (54.28% vs. 39.11%, <I>P</I> < 0.05) and 36 + 24 h (47.24% vs. 32.94%, <I>P</I> < 0.05) groups than among embryos cultured in the absence of dbcAMP. However, the number of total and apoptotic cells was not significantly different between groups. The distribution of actin microfilaments was abnormal in oocytes cultured for 60 h without dbcAMP. In addition, the expression of <I>Wee1B, Myt</I>, and <I>Cdc25B</I> was higher in the control group at 44 h than in the dbcAMP group, but there were no differences in expression at the other time points. In conclusion, dbcAMP treatment delays oocyte maturation and maintains oocyte quality.</P>

Anti-proliferation Effects of Interferon-gamma on Gastric Cancer Cells

Zhao, Ying-Hui,Wang, Tao,Yu, Guang-Fu,Zhuang, Dong-Ming,Zhang, Zhong,Zhang, Hong-Xin,Zhao, Da-Peng,Yu, Ai-Lian Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

IFN-${\gamma}$ plays an indirect anti-cancer role through the immune system but may have direct negative effects on cancer cells. It regulates the viability of gastric cancer cells, so we examined whether it affects their proliferation and how that might be brought about. We exposed AGS, HGC-27 and GES-1 gastric cancer cell lines to IFN-${\gamma}$ and found significantly reduced colony formation ability. Flow cytometry revealed no effect of IFN-${\gamma}$ on apoptosis of cell lines and no effect on cell aging as assessed by ${\beta}$-gal staining. Microarray assay revealed that IFN-${\gamma}$ changed the mRNA expression of genes related to the cell cycle and cell proliferation and migration, as well as chemokines and chemokine receptors, and immunity-related genes. Finally, flow cytometry revealed that IFN-${\gamma}$ arrested the cells in the G1/S phase. IFN-${\gamma}$ may slow proliferation of some gastric cancer cells by affecting the cell cycle to play a negative role in the development of gastric cancer.

녹색신용대출이 중국상업은행의 신용위험에 미치는 영향

Hui-Xin Zhao,제해금 한국유통경영학회 2022 유통경영학회지 Vol.25 No.1

Purpose: The purpose of this study was to examine how green credit loans affect the credit risk of commercial banks in China. The heterogeneity of banks was analyzed, and the synergy with the equity capital ratio was analyzed more innovative in consideration of the impact of the government’s regulatory policy on green credit loans. Research design, data, and methodology: This study focuses on the influence of green credit on the risk of commercial banks in China. Using the sample data of 16 relatively large commercial banks in China from 2009 to 2019, this paper constructs a static panel data model for empirical analysis. Results: First, The results show that the green credit business can significantly reduce the non-performing loan ratio (NPLR) of banks. Second, We found that the green credit ratio (GCR) is positively correlated with the NPLR namely, the green credit ratio and credit risk show a "U-shaped" relationship between credit risk and "pre-down, post-up". Third, The impact of green credit on the credit risk of non-state-owned banks is significantly reduced, while the impact on the credit risk of state-owned commercial banks is not significant, Finally, In view of the interaction of capital adequacy ratio(CAR) and green credit on bank credit risk, we find that banks with higher capital adequacy ratio have a more positive effect on reducing credit risk. Implications: Commercial banks that develop the green credit have risk consideration, especially credit risk. It should be noted that risk management considerations are important for the stability of the banking system. This study provides empirical evidence for commercial banks to reduce the credit risk. The results of this study are helpful in actively promoting China’s green credit loan policy.

The effect of the material factors on the concrete resistance against carbonation

Hui Zhao,Wei Sun,Xiaoming Wu,Bo Gao 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.4

The carbonation is one of the main factors to cause the degradation of the properties in the reinforcement concrete structures. In thisstudy, the effect of the material factors, i.e. the type and the particle size of cement, the calcium oxide content in the fly ash, thefineness modulus of fine aggregate, the types and the dosages of superplasticizers (SPs), on the carbonation properties of the concretewas studied. The carbonation coefficient (K) values of the concrete mixtures with various material factors were obtained. The controlindexes of the material to resist against carbonation of the reinforced concrete were proposed. The test results show that the type andthe particle size of cement, the calcium oxide content in the fly ash and the types of SPs have the significant influence on thecarbonation coefficient (K). The concrete mixture with the excellent resistance against carbonation can be prepared by using cementwith the fine particle size and the high-calcium fly ash and the PCA SP of lower dosage in the concrete.

Properties of the Cu(In,Ga)Se_2 absorbers deposited by electron-beam evaporation method for solar cells

Zhao-Hui Li,조의식,권상직 한국물리학회 2011 Current Applied Physics Vol.11 No.1

Cu(In,Ga)Se_2 thin films were formed using the commercial Cu(In,Ga)Se_2 bulk by electron-beam evaporation method with the various beam current of the irradiated electrons. The experimental results showed that the Cu-rich Cu(In_(1-x)Ga_x)Se_2 films could be deposited successfully when the electron-beam current increased up to 90 mA. After the annealing process at 550℃ for 1 h in the vacuum of 3 × 10^6torr, the as-deposited amorphous Cu(In,Ga)Se_2 thin film was crystallized and the Cu-rich CIGS film was converted to Cu-poor film. The chemical composition the morphology and the band gap of the annealed Cu(In,Ga)Se_2 films were also analyzed.

Antiproliferative Effects of Celecoxib in Hep-2 Cells through Telomerase Inhibition and Induction of Apoptosis

Zhao, Yong-Qiang,Feng, Hui-Wei,Jia, Tao,Chen, Xue-Mei,Zhang, Hui,Xu, An-Ting,Zhang, Hai-Ling,Fan, Xian-Liang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

Background: To investigate the effect of celecoxib on telomerase activity and apoptosis in a human laryngeal squamous carcinoma cell line (Hep-2 cells). Materials and Methods: The growth inhibition rate of Hep-2 cells in vitro was measured by MTT assay, and apoptosis by TUNEL assay and flow cytometry (FCM). The TRAP-ELISA method was used to determine telomerase activity in Hep-2 cells. The mRNA expression of human telomerase RNA component(hTR), human telomerase reverse transcriptase (hTERT) and human telomerase-associated protein(hTEP1) was determined by RT-PCR assay. Expression of Bax and Bcl-2 proteins was assessed by Western blotting. Results: Celecoxib can inhibit proliferation and induce apoptosis in a dose- and time-dependent manner, repress telomerase activity, decrease hTERT mRNA and Bcl-2 protein expression and increase Bax protein expression, PGE2 had no effect on telomerase. Conclusions: Celecoxib had the antiproliferative and pro-apoptotic effect in Hep-2 cells. Apoptosis was accompanied by a decrease in telomerase activity which was directly correlated with hTERT mRNA and up-regulation of Bax/Bcl-2. Bcl-2 may thus play an important role in telomerase activity as well as apoptosis.

Analysis of Ferrous on Ten-Eleven Translocation Activity and Epigenetic Modifications of Early Mouse Embryos by Fluorescence Microscopy

Zhao, Ming-Hui,Liang, Shuang,Guo, Jing,Choi, Jeong-Woo,Kim, Nam-Hyung,Lu, Wen-Fa,Cui, Xiang-Shun Cambridge University Press 2016 Microscopy and Microanalysis Vol.22 No.2

<B>Abstract</B><P>Iron is an essential trace element that plays important roles in the cellular function of all organs and systems. However, the function of Fe(II) in mammalian embryo development is unknown. In this study, we investigated the role of Fe(II) during preimplantation embryo development. Depletion of Fe(II) using thiosemicarbazone-24 (TSC24), a specific Fe(II) chelator, rescued quenching of the Fe(II)-sensitive fluorophore phen green-SK. After <I>in vitro</I> fertilization, TSC24 significantly reduced the cleavage rate as well as blastocyst formation. The hatch rate of blastocysts was also reduced with 1 pM TSC24 treatment (20.25±1.86 versus 42.28±12.96%, <I>p</I><0.05). Blastocysts were cultured in leukemia inhibitory factor-free mouse embryonic stem cell culture medium with or without TSC24, and those with depleted Fe(II) displayed delayed attachment and lost the ability to induce embryoid body formation. To further explore the mechanism of Fe(II) in embryo development, we assessed the expression of 5-hydroxymethylcytosine (5hmC) and OCT4 in the pronuclear and blastocyst stages, respectively. We observed that Fe(II) reduced 5hmC and OCT4 expression, which could be explained by low ten-eleven translocation (TET) enzyme activity induced by TSC24 treatment. These findings demonstrate that Fe(II) is required for mammalian embryo development and that it facilitates the process via regulation of TET activity.</P>