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Biochemical Characterization of Exoribonuclease Encoded by SARS Coronavirus
Chen, Ping,Jiang, Miao,Hu, Tao,Liu, Qingzhen,Chen, Xiaojiang S.,Guo, Deyin Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.5
The nsp14 protein is an exoribonuclease that is encoded by severe acute respiratory syndrome coronavirus (SARS-CoV). We have cloned and expressed the nsp14 protein in Escherichia coli, and characterized the nature and the role(s) of the metal ions in the reaction chemistry. The purified recombinant nsp14 protein digested a 5'-labeled RNA molecule, but failed to digest the RNA substrate that is modified with fluorescein group at the 3'-hydroxyl group, suggesting a 3'-to-5' exoribonuclease activity. The exoribonuclease activity requires $Mg^{2+}$ as a cofactor. Isothermal titration calorimetry (ITC) analysis indicated a two-metal binding mode for divalent cations by nsp14. Endogenous tryptophan fluorescence and circular dichroism (CD) spectra measurements showed that there was a structural change of nsp14 when binding with metal ions. We propose that the conformational change induced by metal ions may be a prerequisite for catalytic activity by correctly positioning the side chains of the residues located in the active site of the enzyme.
Li, Jing-Ping,Cao, Nai-Xia,Jiang, Ri-Ting,He, Shao-Jian,Huang, Tian-Ming,Wu, Bo,Chen, De-Feng,Ma, Ping,Chen, Li,Zhou, Su-Fang,Xie, Xiao-Xun,Luo, Guo-Rong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6
Background: GC-binding factor 2 (GCF2) is a transcriptional regulator that represses transcriptional activity of the epidermal growth factor receptor (EGFR) by binding to a specific GC-rich sequence in the EGFR gene promoter. In addition to this function, GCF2 has also been identified as a tumor-associated antigen and regarded as a potentially valuable serum biomarker for early human hepatocellular carcinoma (HCC) diagnosis. GCF2 is high expressed in most HCC tissues and cell lines including HepG2. This study focused on the influence of GCF2 on cell proliferation and apoptosis in HepG2 cells. Materials and Methods: GCF2 expression at both mRNA and protein levels in HepG2 cells was detected with reverse transcription (RT) PCR and Western blotting, respectively. RNA interference (RNAi) technology was used to knock down GCF2 mRNA and protein expression. Afterwards, cell viability was analyzed with a Cell Counting Kit-8 (CCK-8), and cell apoptosis and caspase 3 activity by flow cytometry and with a Caspase 3 Activity Kit, respectively. Results: Specific down-regulation of GCF2 expression caused cell growth inhibition, and increased apoptosis and caspase 3 activity in HepG2 cells. Conclusions: These primary results suggest that GCF2 may influence cell proliferation and apoptosis in HepG2 cells, and also provides a molecular basis for further investigation into the possible mechanism at proliferation and apoptosis in HCC.
Ping Yao,Jun Zhang,Tieling Xing,Guo-Qiang Chen,Ran Tao,추광호 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.58 No.-
This study focused on the green synthesis of silver nanoparticles (AgNPs) using grape seed extract and their use for the catalytic degradation of a hazardous dye. The reaction temperature for the synthesis had great impacts to the properties of AgNPs and thereby, contributed to their activity for reductive decomposition of Direct Orange 26 by NaBH4. The elevated temperature made silver particles grow bigger and so reduced the effectiveness of surface catalysis. This was evidenced by the decrease in the reaction rate of AgNPs. The biosynthesis of AgNPs below 40 °C had no negative effect on the degradation of Direct Orange 26.
( Ping Lu ),( Ke Jiang ),( Ya-qiao Hao ),( Wan-ying Chu ),( Yu-dong Xu ),( Jia-yao Yang ),( Jia-le Chen ),( Guo-hong Zeng ),( Zhou-hang Gu ),( Hong-xin Zhao ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.9
Members of the genus Bacillus are known to play an important role in promoting plant growth and protecting plants against phytopathogenic microorganisms. In this study, 21 isolates of Bacillus spp. were obtained from the root micro-ecosystem of Suaeda glauca. Analysis of the 16S rRNA genes indicated that the isolates belong to the species Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus subtilis, Bacillus pumilus, Bacillus aryabhattai and Brevibacterium frigoritolerans. One of the interesting findings of this study is that the four strains B1, B5, B16 and B21 are dominant in rhizosphere soil. Based on gyrA, gyrB, and rpoB gene analyses, B1, B5, and B21 were identified as B. amyloliquefaciens and B16 was identified as B. velezensis. Estimation of antifungal activity showed that the isolate B1 had a significant inhibitory effect on Fusarium verticillioides, B5 and B16 on Colletotrichum capsici (syd.) Butl, and B21 on Rhizoctonia cerealis van der Hoeven. The four strains grew well in medium with 1-10% NaCl, a pH value of 5-8, and promoted the growth of Arabidopsis thaliana. Our results indicate that these strains may be promising agents for the biocontrol and promotion of plant growth and further study of the relevant bacteria will provide a useful reference for the development of microbial resources.
In Vitro Biological Characterization of DCUN1D5 in DNA Damage Response
Guo, Wei,Li, Guo-Jun,Xu, Hong-Bo,Xie, Jie-Shi,Shi, Tai-Ping,Zhang, Sheng-Zhong,Chen, Xiao-Hong,Huang, Zhi-Gang Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8
Background: Novel prognostic biomarkers or therapeutic molecular targets for laryngeal squamous cell carcinoma (LSCC) are an urgent priority. We here sought to identify multiple novel LSCC-associated genes. Methods: Using high-density microarray expression profiling, we identified multiple genes that were significantly altered between human LSCCs and paired normal tissues. Potential oncogenic functions of one such gene, DCUN1D5, were further characterized in vitro. Results: Our results demonstrated that DCUN1D5 was highly expressed in LSCCs. Overexpression of DCUN1D5 in vitro resulted in 2.7-fold increased cellular migration, 67.5% increased invasive capacity, and 2.6-fold increased proliferation. Endogenous DCUN1D5 expression was decreased in a time-dependent manner after genotoxic stress, and silencing of DCUN1D5 by siRNA decreased the number of cells in the S phase by 10.2% and increased apoptosis by 11.7%. Conclusion: Our data suggest that DCUN1D5 in vitro might have vital roles in DNA damage response, but further studies are warranted to assess its significance in vivo.
Structural and electronic properties of neutral boron clusters doped with two potassium atoms
Chen Guo Li,Yuan Yu Quan,Wang Chun Ping,Wang Ying Ying,Liu Ting,Huang Teng Xin,Lin Wei,Yang Jing 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.12
This paper reports a systematic study on the doping of two potassium atoms in small-sized neutral boron clusters. The CALYPSO software in conjunction with DFT was used to anticipate the low-energy structures, optimize their geometry, and adjust their energies. With increasing size, the structural development of the K2Bn (n=1–12) clusters was revealed, and we discovered that the majority of their ground-state structural isomers structurally inherited well from the corresponding ground-state isomers of pure B clusters. A fresh fnding was made after confrming the NPA (natural population analysis) of the low-lying K2Bn (n=1–12): every doped K atom in the structure has a positive charge. According to relative stability analysis, the most stable K2B8 cluster within the parameters of our investigation has a HOMO–LUMO gap of 3.31 eV. Strong interactions between K-4s and B-2P AO were also discovered through an additional examination of the molecular orbitals and bonds of K2B8 clusters. These interactions may be the primary cause of K2B8's exceptional stability. We hope that our research will be useful in the future for synthesizing and using doped boron-based nanomaterials.
Li, Ping,Xie, Xiao-Bing,Chen, Qian,Pang, Guo-Lian,Luo, Wan,Tu, Jian-Cheng,Zheng, Fang,Liu, Song-Mei,Han, Lu,Zhang, Jian-Kun,Luo, Xian-Yong,Zhou, Xin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16
Background: Recent studies have indicated that microRNA-15a (miR-15a) is dysregulated in breast cancer (BC). We aimed to evaluate the expression of miR-15a in BC tissues and corresponding para-carcinoma tissues. We also focused on effects of miR-15a on cellular behavior of MDA-MB-231 and expression of its target gene synuclein-${\gamma}$ (SNCG). Materials and Methods: The expression levels of miR-15a were analysed in BC formalin fixed paraffin embedded (FFPE) tissues by microarray and quantitative real-time PCR. CCK-8 assays, cell cycle and apoptosis assays were used to explore the potential functions of miR-15a in MDA-MB-231 human BC cells. A luciferase reporter assay confirmed direct targets. Results: Downregulation of miR-15a was detected in most primary BCs. Ectopic expression of miR-15a promoted proliferation and suppressed apoptosis in vivo. Further studies indicated that miR-15a may directly interact with the 3'-untranslated region (3'-UTR) of SNCG mRNA, downregulating its mRNA and protein expression levels. SNCG expression was negatively correlated with miR-15a expression. Conclusions: MiR-15a has a critical role in mediating cell cycle arrest and promoting cell apoptosis of BC, probably by directly targeting SNCG. Thus, it may be involved in development and progression of BC.
Li Chen,Ali Mohsin,Ju Chu,Ying-ping Zhuang,Yamei Liu,Mei-Jin Guo 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.6
Pichia pastoris strains carrying 1, 6, 12, and 18 copies of the porcine insulin precursor (PIP) gene, were employed to investigate the effects of sorbitol co-feeding with methanol on the physiology of the strains. Multicopy clones of the methylotrophic yeast were generated to vary the PIP gene dosage and recombinant proteins. Elevated gene dosage increased levels of the recombinant PIP protein when methanol served as the sole carbon and energy source i.e., an increase of 1.9% for a strain carrying 1 copy, 42.6% for a strain carrying 6 copies, 34.7% for a strain carrying 12 copies and 80.9% for a strain carrying 18 copies, respectively (using sorbitol co-feeding with methanol during the induction phase). However, it had no significant influence on a lower gene dosage strain (1 copy), but this approach affirmed enhancement in cell growth and PIP production for higher gene dosage strain (6, 12, and 18 copies) via using sorbitol co-feeding with methanol. Additionally, the co-feeding strategy could hold vital importance for recombinant protein production by a multi-copy P. pastoris system.