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( Xi He ),( Ning Han ),( Yan Ping Wang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.1
Lactobacillus kefiranofaciens ZW3 was obtained from kefir grains, which have high lactose hydrolytic activity. In this study, a heterodimeric LacLM-type β-galactosidase gene (lacLM) from ZW3 was isolated, which was composed of two overlapping genes, lacL (1,884 bp) and lacM (960 bp) encoding large and small subunits with calculated molecular masses of 73,620 and 35,682 Da, respectively. LacLM, LacL, and LacM were expressed in Escherichia coli BL21(DE3) and these recombinant proteins were purified and characterized. The results showed that, compared with the recombinant holoenzyme, the recombinant large subunit exhibits obviously lower thermostability and hydrolytic activity. Moreover, the optimal temperature and pH of the holoenzyme and large subunit are 60oC and 7.0, and 50oC and 8.0, respectively. However, the recombinant small subunit alone has no activity. Interestingly, the activity and thermostability of the large subunit were greatly improved after mixing it with the recombinant small subunit. Therefore, the results suggest that the small subunit might play an important role in maintaining the stability of the structure of the catalytic center located in the large subunit.
( Xi He ),( Mingjian Luan ),( Ning Han ),( Ting Wang ),( Xiangzhong Zhao ),( Yanyan Yao ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.4
Lactobacillus kefiranofaciens contains two types of β-galactosidase, LacLM and LacZ, belonging to different glycoside hydrolase families. The difference in function between them has been unclear so far for practical application. In this study, LacLM and LacZ from L. kefiranofaciens ATCC51647 were cloned into constitutive lactobacillal expression vector pMG36e, respectively. Furtherly, pMG36nlacs was constructed from pMG36e-lacs by replacing erythromycin with nisin as selective marker for food-grade expressing systems in Lactobacillus plantarum WCFS1, designated recombinant LacLM and LacZ respectively. The results from hydrolysis of o-nitrophenyl-β-galactopyranoside (ONPG) showed that the β-galactosidases activity of the recombinant LacLM and LacZ was 1460% and 670% higher than that of the original L. kefiranofaciens. Moreover, the lactose hydrolytic activity of recombinant LacLM was higher than that of LacZ in milk. Nevertheless, compare to LacZ, in 25% lactose solution the galacto-oligosaccharides (GOS) production of recombinant LacLM was lower. Therefore, two β-galactopyranosides could play different roles in carbohydrate metabolism of L. kefiranofaciens. In addition, the maximal growth rate of two recombinant strains were evaluated with different temperature level and nisin concentration in fermentation assay for practical purpose. The results displayed that 37oC and 20-40 U/ml nisin were the optimal fermentation conditions for the growth of recombinant β-galactosidase strains. Altogether the food-grade Expression system of recombinant β-galactosidase was feasible for applications in the food and dairy industry.
Huang, Xi,Ouyang, Xinhao,Yang, Panyu,Lau, On Sun,Chen, Liangbi,Wei, Ning,Deng, Xing Wang National Academy of Sciences 2013 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.110 No.41
<P>The evolutionarily conserved CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) is a RING and WD40 protein that functions as a substrate receptor of CULLIN4–DAMAGED DNA BINDING PROTEIN 1 (CUL4–DDB1)–based E3 ubiquitin ligases in both plants and animals. In <I>Arabidopsis</I>, COP1 is a central repressor of photomorphogenesis in the form of COP1–SUPPRESSOR OF PHYA (SPA) complex(es). CUL4–DDB1–COP1–SPA suppresses the photomorphogenic program by targeting the transcription factor ELONGATED HYPOCOTYL 5 for degradation. Intriguingly, under photomorphogenic UV-B light, COP1 reverses its repressive role and promotes photomorphogenesis. However, the mechanism by which COP1 is functionally switched is still obscure. Here, we demonstrate that UV-B triggers the physical and functional disassociation of the COP1–SPA core complex(es) from CUL4–DDB1 and the formation of a unique complex(es) containing the UV-B receptor UV RESISTANCE LOCUS 8 (UVR8). The establishment of this UV-B–dependent COP1 complex(es) is associated with its positive modulation of ELONGATED HYPOCOTYL 5 stability and activity, which sheds light on the mechanism of COP1’s promotive action in UV-B–induced photomorphogenesis.</P>
Han Ning,Li Lanxin,Wang Fengjie,Yang Zhen,He Xi 한국원예학회 2024 Horticulture, Environment, and Biotechnology Vol.65 No.1
Anthocyanin accumulation in the skin of red/black grape berries is a crucial quality parameter that is known to be infl uenced by salt content. During two consecutive seasons, we applied a mild salinity NaCl solution (20 mmol L −1 and 60 mmol L −1 ) to the grapevine canopy in a commercial vineyard to investigate anthocyanin biosynthesis during berry ripening. The results showed a gradual reduction in the mass of mature berries as the concentration of NaCl increased. However, the contents of reducing sugars, total phenols, and tannins exhibited an inverse trend. Compared to the control group, the treatment with 60 mmol L −1 NaCl signifi cantly hindered ABA synthesis in berries at véraison. This reduction was associated with lower levels of anthocyanin and sugar accumulation, which was determined by the downregulation of key genes involved in the related pathways during the early stages of berry ripening. Conversely, during the late stages of berry ripening, there was a notable increase in both anthocyanin and sugar accumulation with rising NaCl levels. This observation aligned with the upregulation of key genes involved in anthocyanin metabolism and sugar transport. However, unlike the early stages, the ABA content in berries did not correlate with anthocyanin synthesis during the late stages of ripening under salt stress. Therefore, we concluded that anthocyanin accumulation was regulated under NaCl stress during berry ripening and exhibited diff er ent accumulation profi les at diff erent developmental stages. Additionally, we noticed that the proportion of dihydroxylated/ trihydroxylated anthocyanins was increased in salt-stressed berries at harvest, while the proportion of acylated anthocyanins was notably decreased. In summary, the fi ndings suggested that the alteration in anthocyanin accumulation varied across diff erent developmental stages of berries under moderate salinity stress.
Research on Discontinuous Pulse Width Modulation Algorithm for Single-phase Voltage Source Rectifier
Yang, Xi-Jun,Qu, Hao,Tang, Hou-Jun,Yao, Chen,Zhang, Ning-Yun,Blaabjerg, Frede Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.4
Single phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). As the fundamental part of large scale PECs, single-phase VSC has a wide range of applications. In the paper, as first, on the basis of the concept of the discontinuous pulse-width modulation (DPWM) for three-phase VSC, a new DPWM of single-phase VSR is presented by means of zero-sequence component injection. Then, the transformation from stationary frame (abc) to rotating frame (dq) is designed after reconstructing the other orthogonal current by means of one order all-pass filter. Finally, the presented DPWM based single-phase VSR is established analyzed and simulated by means of MATLAB/SIMULINK. In addition, the DPWMs presented by D. Grahame Holmes and Thomas Lipo are discussed and simulated in brief. Obviously, the presented DPWM can also be used for single-phase VSI, GCI and APF. The simulation results show the validation of the above modulation algorithm, and the DPWM based single-phase VSR has reduced power loss and increased efficiency.
JIN XI,XIAN NING 국제온돌학회 2017 International Journal of Ondol Vol.10 No.1
The main goal of the Green Building Council is to create a prosperous and sustainable future through cost control and energy saving. Some positive measures have been adopted by the Green Building Council to take the construction industry in order to promote sustainable cost control of the construction of a number of architectural practices. In order to reduce the consumption of fossil fuels in the future, sustainable development in the system of education in the construction of large-scale implementation. Green buildings are designed to reduce operating costs to reduce energy consumption, but some of the artical on green buildings consume more energy than non green buildings. In this paper, the construction cost and the construction period of the data is from the specific area of the 30 green building and 30 non green education construction. Statistical tests are used to determine whether there is a clear difference between the construction cost and the construction period. Test results show that the cost and duration of the green building are significantly higher than those of the non green building. The findings are helpful to further research on the life cycle of the building.
Zhu, Xi,Xu, Yingjie,Solis, Luisa M.,Tao, Wei,Wang, Liangzhe,Behrens, Carmen,Xu, Xiaoyang,Zhao, Lili,Liu, Danny,Wu, Jun,Zhang, Ning,Wistuba, Ignacio I.,Farokhzad, Omid C.,Zetter, Bruce R.,Shi, Jinjun National Academy of Sciences 2015 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.112 No.25
<P><B>Significance</B></P><P>This study developed a new generation lipid–polymer hybrid nanoparticle platform for effective systemic delivery of small interfering RNA (siRNA) to tumors, which represents a challenging hurdle for the widespread application of RNA interference (RNAi) in cancer research and therapy. With promising in vivo features such as long blood circulation, high tumor accumulation, and effective gene silencing, the hybrid siRNA nanoparticles were successfully used to reveal and validate a putative therapeutic target, Prohibitin1 (PHB1), in non-small cell lung cancer treatment. In vivo antitumor efficacy results and human tissue microarray analysis further suggested the feasibility of utilizing PHB1 siRNA nanoparticles as a novel therapeutic agent. This hybrid RNAi nanoparticle platform may serve as a valuable tool for validating potential cancer targets and developing new cancer therapies.</P><P>RNA interference (RNAi) represents a promising strategy for identification and validation of putative therapeutic targets and for treatment of a myriad of important human diseases including cancer. However, the effective systemic in vivo delivery of small interfering RNA (siRNA) to tumors remains a formidable challenge. Using a robust self-assembly strategy, we develop a unique nanoparticle (NP) platform composed of a solid polymer/cationic lipid hybrid core and a lipid-poly(ethylene glycol) (lipid-PEG) shell for systemic siRNA delivery. The new generation lipid–polymer hybrid NPs are small and uniform, and can efficiently encapsulate siRNA and control its sustained release. They exhibit long blood circulation (<I>t</I><SUB>1/2</SUB> ∼8 h), high tumor accumulation, effective gene silencing, and negligible in vivo side effects. With this RNAi NP, we delineate and validate the therapeutic role of Prohibitin1 (PHB1), a target protein that has not been systemically evaluated in vivo due to the lack of specific and effective inhibitors, in treating non-small cell lung cancer (NSCLC) as evidenced by the drastic inhibition of tumor growth upon PHB1 silencing. Human tissue microarray analysis also reveals that high PHB1 tumor expression is associated with poorer overall survival in patients with NSCLC, further suggesting PHB1 as a therapeutic target. We expect this long-circulating RNAi NP platform to be of high interest for validating potential cancer targets in vivo and for the development of new cancer therapies.</P>