A Newly Identified Glutaminase-Free L-Asparaginase (L-ASPG86) from the Marine Bacterium Mesoflavibacter zeaxanthinifaciens

( Su Jin Lee ),( Youngdeuk Lee ),( Gun Hoo Park ),( Navaneethaiyer Umasuthan ),( Soo Jin Heo ),( Mahanama De Zoysa ),( Won Kyo Jung ),( Dae Won Lee ),( Hanjun Kim ),( Do Hyung Kang ),( Chulhong Oh ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.6

L-Asparaginase (E.C. 3.5.1.1) is an enzyme involved in asparagine hydrolysis and has the potential to effect leukemic cells and various other cancer cells. We identified the Lasparaginase gene (L-ASPG86) in the genus Mesoflavibacter, which consists of a 1,035 bp open reading frame encoding 344 amino acids. Following phylogenetic analysis, the deduced amino acid sequence of L-ASPG86 (L-ASPG86) was grouped as a type I asparaginase with respective homologs in Escherichia coli and Yersinia pseudotuberculosis. The L-ASPG86 gene was cloned into the pET-16b vector to express the respective protein in E. coli BL21 (DE3) cells. Recombinant L-asparaginase (r-L-ASPG86) showed optimum conditions at 37-40oC, pH 9. Moreover, r-L-ASPG86 did not exhibit glutaminase activity. In the metal ions test, its enzymatic activity was highly improved upon addition of 5 mM manganese (3.97-fold) and magnesium (3.35-fold) compared with the untreated control. The specific activity of r-LASPG86 was 687.1 units/mg under optimum conditions (37°C, pH 9, and 5 mM MnSO4).

The Trajectory of University Science Parks (USPs) in China

De-Jin Su,Bei Wu,Dong-Won Sohn,Da-Yong Zhou 과학기술정책연구원 2016 STI Policy Review Vol.7 No.2

This study aims to identify the chronological trajectory of university science parks (USPs) in China and to discuss the roles of government-driven science and technology (S&T) policies in the development of USPs and the future directions of these entities. Our study shows that USPs in China have undergone two development waves: The first from the late 1980s to the late 1990s, when research universities expected to directly participate in economic activities, and the second from 2000 when the Ministry of Science and Technology (MOST) and the Ministry of Education (MOE) jointly enacted the Proposed Regulation of State-level USPs Management to guide and regulate the development of USPs. The development trajectory highlights that USPs are effective platforms that link scientific research, knowledge spillovers and industrial system. However, Chinese USPs still need to confront some conundrums which may influence the processes and outcomes of UILs. Finally, we also summarize the major issues inherent in the development of USPs to guide policymakers to enact more effective policies.

Chinese Policy to Stimulate University - Industry Linkages in Nanjing

De-Jin Su,Dong-Won Sohn,Sunwoo Sohn 과학기술정책연구원 2013 STI Policy Review Vol.4 No.2

Rapid changes in the economic, social and academic environments often provide opportunities to develop new and advanced technologies. In China, recent literature on the role of universities suggests that university - industry linkages (UILs) play a substantial role in the development of high-tech industries. Since 1979 when the country became more open and underwent economic reform, Chinese central authorities, local governments, and universities have continued to set up various science and technology (S&T) policies to stimulate UILs, contributing to China’s technological progress and economic growth. This study examines the role of S&T policies on UILs such as transfer of technology, joint research, and spin-off creation with a particular focus on Nanjing University (NJU) in Jiangsu Province. Nanjing has over 53 universities, ranking it behind Beijing and Shanghai in terms of S&T and higher education opportunities. By adopting “institutional methodology,” this study contends that UILs not only benefit universities and industry but also society in terms of job training, consulting activities, joint research, R&D results commercialization, patent licensing, new business creation, and other aspects. Finally, we suggest that the Chinese experience, though with some problems, might enhance our understanding of how to stimulate UILs through the arrangement of various S&T policies.

Roles of entrepreneurial orientation and guanxi network with parent university in start-ups’ performance: evidence from university spin-offs in China

De-Jin Su,손동원 기술경영경제학회 2015 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.23 No.1

The aim of this study is to examine the roles of entrepreneurial orientation (EO) and the guanxinetwork with parent university (GNPU) in the creation of university spin-offs (USOs). Thestudy replicates and extends previous research on academic entrepreneurship by providingan empirical analysis using data from 140 USOs in China. The empirical results indicatethat three dimensions of EO (innovativeness: IN; proactiveness: PR; and risk-taking: RT)and GNPU have positive effects on the financial performance (FP); PR, RT, and GNPUhave positive effects on non-financial performance (NFP) of USOs. In the context ofmoderating effects, this study finds that only GNPU positively moderates the relationshipsbetween IN and FP as well as between PR and NFP, failing to find others. Generallyspeaking, EO is an important strategic asset and GNPU is an important organisationalresource that underpin the establishment of USOs. In addition, we also provide someimportant theoretical and practical implications for scholars, practitioners, and policy-makers

What Promotes International Sustainable Development of Green Ventures? The Joint Effects of Entrepreneurial Orientation and Home Country-Based Networks

De-Jin Su,김영길 한국무역학회 2022 Journal of Korea trade Vol.26 No.4

Purpose – Along with the growing awareness of environmental sustainability, international green entrepreneurship is expected to realize international sustainable development (ISD) by introducing ecological innovation results, using fewer resources consumption, and reducing negative environmental impacts. Building upon contingency theory and social network theory, this paper attempts to explore the role of home country-based networks (technology ties and business ties) as contingent factors that might impact the effectiveness of entrepreneurial orientation (EO) in promoting ISD among green ventures. Design/methodology – Original data were collected from 127 green ventures in China based on the random sampling technique. These green ventures mainly focus on the lower use of energy or materials, lower CO2 emissions, and higher ecological benefits located in the Fujian province, which highlights green economic growth and economic cooperation with international markets. Moderated hierarchical linear regression analysis was conducted to test our hypotheses concerning the main relationship between EO (innovativeness, proactiveness, and risk-taking) and ISD as well as the moderating effects of home country-based networks (technology ties and business ties) on the main relationship. Findings – Empirical results indicate that: first, both innovativeness and proactiveness positively affect ISD; second, both technology ties and business ties at home might significantly strengthen the positive relationship between innovativeness (or proactiveness) and ISD. However, this study did not find significant moderating effects of technology ties or business ties at home on the relationship between risk-taking and ISD. Originality/value – Since previous literature often gives more focus on the host country context of social networks, this study shifts to a home country-based network context. Therefore, our research might enrich the international green entrepreneurship literature by empirically investigating the contingent value of home country-based networks in the relationship between EO and ISD in the context of an emerging economy such as China.

Software Technology Integrated Smart Machine Tool Development for Mold Machining

De-Yu Park(박대유),Kyu-Yeong Yum(엄규용),Hyun-Yeong Cho(조현용),Du-Jin Kim(김두진),Jae-Keun Park(박재근),Su-Jin Kim(김수진) Korean Society for Precision Engineering 2018 한국정밀공학회지 Vol.35 No.2

A New Synthetic Histone Deacetylase Inhibitor, MHY2256, Induces Apoptosis and Autophagy Cell Death in Endometrial Cancer Cells via p53 Acetylation

De, Umasankar,Son, Ji Yeon,Sachan, Richa,Park, Yu Jin,Kang, Dongwan,Yoon, Kyungsil,Lee, Byung Mu,Kim, In Su,Moon, Hyung Ryong,Kim, Hyung Sik MDPI 2018 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.19 No.9

<P>We previously discovered a novel sirtuin (SIRT) inhibitor, MHY2256, that exerts anticancer activity through p53 acetylation in MCF-7 human breast cancer cells. We investigated the anticancer activity of MHY2256 against hormone-related cancer, an endometrial cancer with a poor prognosis. The IC<SUB>50</SUB> values of MHY2256 were shown to be much lower than those of salermide, a well-known SIRT inhibitor. Furthermore, MHY2256 significantly reduced the protein expression and activities of SIRT1, 2, and 3, with similar effects to salermide. Particularly, MHY2256 markedly inhibited tumor growth in a tumor xenograft mouse model of Ishikawa cancer cells. During the experimental period, there was no significant change in the body weight of mice treated with MHY2256. A detailed analysis of the sensitization mechanisms of Ishikawa cells revealed that late apoptosis was largely increased by MHY2256. Additionally, MHY2256 increased G1 arrest and reduced the number of cell cyclic-related proteins, suggesting that apoptosis by MHY2256 was achieved by cellular arrest. Particularly, p21 was greatly increased by MHY225656, suggesting that cell cycle arrest by p21 is a major factor in MHY2256 sensitization in Ishikawa cells. We also detected a significant increase in acetylated p53, a target protein of SIRT1, in Ishikawa cells after MHY2256 treatment. In a mouse xenograft model, MHY2256 significantly reduced tumor growth and weight without apparent side effects. These results suggest that MHY2256 exerts its anticancer activity through p53 acetylation in endometrial cancer and can be used for targeting hormone-related cancers.</P>

Plumbagin from a tropical pitcher plant (<i>Nepenthes alata</i> Blanco) induces apoptotic cell death via a p53-dependent pathway in MCF-7 human breast cancer cells

De, Umasankar,Son, Ji Yeon,Jeon, Yukyoung,Ha, Song-Yi,Park, Yu Jin,Yoon, Sungpil,Ha, Ki-Tae,Choi, Wahn Soo,Lee, Byung Mu,Kim, In Su,Kwak, Jong Hwan,Kim, Hyung Sik Elsevier 2019 Food and chemical toxicology Vol.123 No.-

<P><B>Abstract</B></P> <P>Plumbagin (5-hydroxy-2-methyl-1,4-naphthaquinone) has displayed antitumor activity <I>in vitro</I> and in animal models; however, the underlying molecular mechanisms have not been fully explored. The aim of this study was to investigate the anticancer effects of plumbagin isolated from <I>Nepenthes alata</I> against MCF-7 breast cancer cells. We examined the cytotoxicity, cell cycle regulation, apoptotic cell death, and generation of intracellular reactive oxygen species (ROS) in MCF-7 cells. Plumbagin exhibited potent cytotoxicity in MCF-7 cells (wild-type p53) compared to that in SK-OV-3 (null-type) human epithelial ovarian cancer cells. Specifically, plumbagin upregulated the expression of p21<SUP>CIP1/WAF1</SUP> in MCF-7 cells, causing cell cycle arrest in the G2/M phase through inhibition of cyclin B1 levels. Plumbagin also significantly increased the ratio of Bax/Bcl-2 and release of cytochrome c, resulting in apoptotic cell death in MCF-7 cells. Furthermore, plumbagin dramatically increased the intracellular ROS level, whereas pretreatment with the ROS scavenger N-acetyl cysteine protected against plumbagin-induced cytotoxicity, suggesting that ROS formation plays a pivotal role in antitumor activity in MCF-7 cells. In mice bearing MCF-7 cell xenografts, plumbagin significantly reduced tumor growth and weight without apparent side effects. We therefore concluded that plumbagin exerts anticancer activity against MCF-7 cells through the generation of intracellular ROS, resulting in the induction of apoptosis via a p53-dependent pathway. This study thus identifies a new anticancer mechanism of plumbagin against p53-dependent breast cancer cells and suggests a novel strategy for overcoming of breast cancer therapy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Plumbagin, first isolated from <I>N. alata</I>, exhibits anticancer activity in human breast cancer MCF-7 cells. </LI> <LI> ROS generation contributes to the cytotoxicity of plumbagin against MCF7 cells. </LI> <LI> Plumbagin act as a lead molecule for new anticancer drug against breast cancer patients. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Minimization of Surface Roughness and Machining Deformation in Milling of Al Alloy Thin-Walled Parts

De-Jun Cheng,Feng Xu,Sheng-Hao Xu,Chun-Yan Zhang,Sheng-Wen Zhang,Su-Jin Kim 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.9

This study focused on investigating the surface roughness in the feed direction (R a -Fd), surface roughness in the transversedirection (R a -Td), and thin-walled parts deformation (TWD) during milling of Al alloy 5083. The response surface method(RSM) was used to conduct experiments and establish the models of R a -Fd , R a -Td , and TWD under various cutting parameters. The significance of cutting parameters on R a -Fd , R a -Td , and TWD was analyzed by analysis of variance. It was observedthat the R a -Fd and R a -Td are mainly influenced by the spindle speed, depth of cut, transverse size and feed rate, while the TWD is mainly influenced by the depth of cut. A comparison of RSM-optimum function and artificial bee colony (ABC)algorithm optimum programming was conducted to obtain the best cutting conditions leading to minimum R a -Fd, R a -Td and TWD simultaneously. From the presented results, ABC algorithm was able to obtain the better cutting strategy. Finally, theperformance of the proposed cutting strategy was verified by confirmation experiments.

Friction Experiment of Linear Motion Roller Guide THK SRG25

Cheng, De-Jun,Yang, Wan-Suk,Park, Je-Hong,Park, Tae-Jo,Kim, Su-Jin,Kim, Gyung-Ho,Park, Chun-Hong 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.3

Friction is a characteristic that can be found in machine elements in common engineering use, and it has great effect on the machining performance of a machine tool. Linear motion (LM) guides supported by rolling elements are used for accurate positioning of precision machine. For accurate positioning, the frictional behavior of the LM guide must be understood. In this investigation, a new experiment is conducted to measure friction, and the behavior of LM roller guide friction is measured under various external loads, preloads, velocities, and lubricants. The results obtained from experiment are compared with reference data, and the experimental friction equation of LM roller guide THK SRG25 is achieved from experiment, which can be used to calculate LM roller guide friction and control positioning accuracy.