1.Prediction models of stroke risk after transient ischemic attack
Pei CHEN ; Lulu PEI ; Yuming XU ; Bo SONG
International Journal of Cerebrovascular Diseases 2015;23(12):924-927
The risk of stroke increases significantly after transient ischemic attack (TIA). TIA is an independent risk factor for cerebral infarction. This article review s the advances in prediction models of stroke risk after TIA in order to conduct rapid and accurate risk assessment and stratification in patients w ith TIA and develop timely reasonable treatment strategies, thereby reducing the risk of stroke.
2.Production of Restriction Endonuclease Not Ⅰ Utilizing CpG DNA Methylase M.Sss Ⅰ Co-expression Vector
Pei WANG ; Kai CHEN ; Song GAO
China Biotechnology 2017;37(8):51-58
Restriction endonucleases are important molecular biology tools for DNA recombination.Because of the cleavage of DNA,their recombinant expression is difficult with low yields and complicated purification processes.In commercial productions,the technology that uses specific methylases to protect host DNA from digestion of the expressed restriction enzymes was cumbersome and practically limited.For solving this problem the expression of restriction enzyme Not Ⅰ was performed by using the DNA methylase M.Sss Ⅰ derived from Spiroplasma sp.MQ1 which specifically kept CpG sequence methylated.The methylated DNA was protected from the cutting of Not Ⅰ whose recognition sequence contained CpG.The gene of methylase M.Sss Ⅰ was introduced into Escherichia coli ER2566 and constitutively expressed,resulting in the CpG methylation pattern of the host DNA.Restriction enzyme Not Ⅰ was successfully expressed in this E.coli strain.Furthermore,by adding a purification tag to one terminus of the enzyme,recombinant Not Ⅰ was prepared as a highly purified and active product through two simple Ni-affinity and anion exchange chromatography steps.This expression system can be applied for the preparation of a series of restriction enzymes with CpG in their recognition sequences.
3.Effects of VEGF on proliferation and morphology of hBMSCs
Bin CHEN ; Yanbin SONG ; Guoxian PEI
Chinese Journal of Orthopaedic Trauma 2008;10(7):659-661
Objective To observe the influences of VEGF transfection on the proliferation and ultrastructure of hBMSCs. Methods Three groups were enrolled in the experiment: group of Ad-VEGF transfection, group of empty Ad transfection, and the control group. Cells were observed continually by inverted phase contrast microscope, and stained by HE. Proliferation of cells was tested by MTT and by flow cytometry analysis. Results Histological observation and observation through inverted phase contrast microscope showed that the cells were of the similar morphology in the 3 groups. As time elapsed, the amount of cells increased, but still no obvious differences were found in optical density (OD) value of hBMSCs.Groups B, C, A had a similar percentage of DNA G1 period and a similar proliferation index (PrI) ( P >0. 05). Conclusion Transfeetion of VEGF has no obvious influence on the prohferation and morphologyof hBMSCs in vitro.
4.Method for Japanese encephalitis virus NS3 protease activity analysis and high-throughput screening assay for inhibitors.
Jingyun ZHOU ; Xue WANG ; Chao PEI ; Yunfeng SONG ; Huanchun CHEN
Chinese Journal of Biotechnology 2014;30(2):194-202
Japanese encephalitis virus (JEV) is a single-stranded and positive-sense RNA, which has a single ORF (open reading frame), encoding a polyprotein precursor. Non-structural protein 3 (NS3) plays an important role in processing the polyprotein precursor and has become an important drug target of flavivirus. In this study, NS2BH-NS3 gene was amplified by PCR and subcloned to the prokaryotic expression plasmid, resulting pET30a-NS2BH-NS3. The fusion protein was expressed in Escherichia coli BL21 (DE3) in soluble form after induction by Isopropyl beta-D-1-Thiogalactopyranoside (IPTG). The recombinant protein was purified by Ni-NTA affinity column. Then a fluorescence resonance energy transfer (FRET) method was used to determine enzymatic activity and the assay conditions were optimized. After screening 113 compounds, we found two compounds inhibiting the activity of NS2BH-NS3. This study provides a convenient and cost-effective method for screening of JEV NS3 protease inhibitor.
Encephalitis Virus, Japanese
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enzymology
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Escherichia coli
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metabolism
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High-Throughput Screening Assays
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Protease Inhibitors
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chemistry
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RNA Helicases
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metabolism
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Recombinant Fusion Proteins
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metabolism
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Serine Endopeptidases
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metabolism
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Viral Nonstructural Proteins
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metabolism
5.Insulin promotes rhesus retinal vascular endothelial cells angiogenesis via VEGF-A/VEGFR2 pathway
Saijun ZHOU ; Song CHEN ; Pei YU ; Demin YU
Chinese Journal of Endocrinology and Metabolism 2010;26(10):891-893
Rhesus retinal vascular endothelial cell line RF/6A cells were treated with human insulin. Cell proliferation, migration, and lumen formation, as well as the expressions of vascular endothelial growth factor-A ( VEGF-A ), VEGF-A receptors, and phosphorylated receptors were measured. Insulin promoted RF/6A cell proliferation, migration, and lumen formation ( all P<0. 01 ). Insulin increased the expression of VEGF-A mRNA and improved its protein activity ( all P<0. 05 ), and promoted the expression of VEGFR2 mRNA and its phosphorylation ( both P<0. 01 ). There was no significant difference in the expression of VEGFR1 mRNA among the groups ( P>0. 05 ).
6.The Gene Cloning, Expression and Bioactivity of the Human FKBP52
Wuhong PEI ; Yonghuai HE ; Xing CHEN ; Song LI ; Beifen SHEN
Progress in Biochemistry and Biophysics 2001;28(2):236-239
To obtain active hFKBP52 protein for screening novel neu rotrophic drugs. Semi-nested and overlap PCR and affinity chromatography were u sed. hFKBP52 gene was cloned successfully from human fetal brain cDNA library, a nd then highly expressed (about 30%) as fusion protein in pET28a(+) vector syste m. The recombinant protein was purified as one band on SDS-PAGE. The purified h FKBP52 showed peptidyl-prolyl cis-trans isomerase (PPIase) activity, simil ar to the wild type.
7.Molecular identification of Cynomorii herba using ITS2 DNA barcoding.
Dian-Yun HOU ; Jing-Yuan SONG ; Lin-Chun SHI ; Pei YANG ; Shi-Lin CHEN ; Hui YAO
China Journal of Chinese Materia Medica 2013;38(23):4028-4032
OBJECTIVETo identify the Cynomorii Herba and its analogues species using DNA barcoding technique.
METHODTotal genomic DNA extracted from all materials using the DNA extraction kit. The internal transcribed spacer 2 (ITS2) regions were amplified using polymerase chain reaction (PCR), and purified PCR products were sequenced bi-directionally. Sequence assembly and consensus sequence generation were performed using the CodonCode Aligner 3.7.1. The Kimura 2-Parameter (K2P) distances and GC content were computed using MEGA 5. 0. Species identification analyses were conducted through the species identification system for traditional Chinese medicine and neighbor-joining (NJ) trees.
RESULTThe ITS2 sequence lengths of Cynomorii Herba were 229 bp. The average intra-specific genetic distances of Cynomorii Herba were 0.003. The average inter-specific genetic distances between Cynomorii Herba and its adulterants species were 0.760. The results showed that the minimum inter-specific divergence is larger than the maximum intra-specific divergence. The species identification system for traditional Chinese medicine and NJ trees results indicated that Cynomorii Herba and its adulterants species can be easily identification.
CONCLUSIONThe ITS2 region is an efficient barcode for identification of Cynomorii Herba, which provide a new technique to ensure clinical safety in utilization of traditional Chinese medicine.
Cynomorium ; classification ; genetics ; DNA Barcoding, Taxonomic ; DNA, Intergenic ; genetics ; DNA, Plant ; genetics ; Polymerase Chain Reaction
8.Heat-killed Staphylococcus aureus induces a common early response in human monocytes in the presence of high concentration glucose
Ying CHEN ; Yan ZHANG ; Xin SONG ; Pei SUN ; Bai CHANG ; Haidong LI ; Dong MENG ; Qiaofen LI
Chinese Journal of Microbiology and Immunology 2012;(12):1005-1010
Objective To investigate the effects of heat-killed Staphylococcus aureus (HKSA) on the apoptosis and expression of iNOS and IL-1β in THP-1 monocytes in the presence of high concentration of glucose.Methods THP-1 cells were cultured in medium containing 25.0 mmol/L(HG) or 5.5 mmol/L (LG,control) D-glucose for 12 h-8 d.The THP-1 cells cultured for 6 d were extracted on the 0-48 h with or without HKSA,then apoptosis and expression of iNOS and IL-1β were examined.Apoptosis was analyzed by flow cytometry and expressions of IL-1β and iNOS were quantitated by real-time PCR.Results The expression of iNOS and IL-1β in THP-1 monocytes was increased significantly in the presence of high concentration of glucose for 12-48 h(P<0.05),reaching the highest level at 24 h and returned to baseline after 4 d.The expression was significantly lower than that of control after 4-6 d.Apoptosis rate was also increased significantly after 48 h to 4 days.HKSA infection enhanced apoptosis,but inhibited the expression of iNOS and IL-1 β in the presence of high concentration of glucose.The expression of iNOS and IL-1β increased significantly at 6 h(P<0.01),reaching the highest level at 12 h,but the levels were significantly lower than those in control groups (P<0.05).Conclusion These data suggest that high concentration of glucose can interfere with the anti-bacterial function of monocytes by reducing their expression of iNOS and IL-1β and enhancing their apoptosis.
9.Long-term follow-up of perfluorodeclin liquid in the anterior chamber
Song CHEN ; Bingshui ZHAO ; Yan LI ; Shurong WU ; Pei LIU ; Qiaolan HONG
Recent Advances in Ophthalmology 2000;20(5):345-347
Objective To observe the effects of residual perfluorocarbon liquid(PFCL) droplets in the anterior chamber in patients after vitreoretinal(VR) surgery for complicated retinal detachments.Methods The study group consisted of nine patients(nine eyes)aged 16~64 in whom droplets of perfluorodeclin liquid(PFDL) appeared in the anterior chamber subsequent to VR surgery for complicated retinal detachments involving scleral bucking, vitrectomy and/or lensectomy, the peeling of pre-retinal membrane, perfluorodecalin injection, and perfluorodeclin liquid-silicone oil or fluid-air exchange. Mean follow-up was 10.3 months.Results Three to 30 droplets of perfluorodeclin liquid were found in the anterior chambers in 9 eyes. There was no corneal complication or inflammatory reactions or blood vessel invasion into the corneal stroma or increased intraocular pressure.Conclusion Residual perfluorodeclin liquid droplets in the anterior chamber are well tolerated and do not induce corneal damage or ocular inflammation.
10.Novel Evidence Suggests Hepatitis B Virus Surface Proteins Participate in Regulation of HBV Genome Replication
Jian QIU ; Bo QIN ; Simon RAYNER ; Chunchen WU ; Rangjuan PEI ; Song XU ; Yun WANG ; Xinwen CHEN
Virologica Sinica 2011;26(2):131-138
Naturally occurring mutations in surface proteins of Hepatitis B virus(HBV)usually result in altered hepatitis B surface antigen(HBsAg)secretion efficiency.In the present study,we reported two conserved residues,M75 and M103 with respect to HBsAg,mutations of which not only attenuated HBsAg secretion(M75 only),but also suppressed HBV genome replication without compromising the overlapping p-gene product.We also found M75 and M103 can initiate truncated surface protein(TSPs)synthesis upon over-expression of full-length surface proteins,which may possibly contribute to HBV genome replication.However,attempts to rescue replicationdefective HBV mutant by co-expression of TSPs initiated from M75 or M103 were unsuccessful,which indicated surface proteins rather than the putative TSPs were involved in regulation of HBV genome replication.