In order to study the structure-function relationship in the protein which is incorporated with p-nitro-L-phenylalanine,the method of MD(Molecular Dynamics) simulation was established and successfully used in the analysis of protein which contains p-nitro-L-phenylalanine.The force field of CHARMM can only stimulate protein with natural amino acid in NAMD.Compared with phenylalanine,p-nitro-L-phenylalanine just has one more group of nitro.If the parameter of group of nitro was defined,the protein containing p-nitro-L-phenylalanine can be simulated.CGenFF-paramchem was used to calculate the energy and topological structure of p-nitro-L-phenylalanine' s new bonds (r),angles (θ),dihendrals (φ) and improper angle (ψ).And then the new defined parameter and topology information was input into the related parameter files and topology files in CHARMM.On the basis of correct parameter,NAMD can successfully simulate the modified BAFF(B lymphocyte stimulator) which contains p-nitro-L-phenylalanine.The changes in structure indicated that there might be new B cell epitopes.The temperature distribution of each frame in the process of dynamics stimulation was in accord with normal distribution,which proved the defined force field parameters was feasible.The RMSD of whole protein solution systemis 2.5.Calculate each resides' RMSF in BAFF,the RMSF of p-nitro-L-phenylalanine's residue is 3.7,which is obviously higher than that of the other residues in β-pleated sheet,and close to the loop rings,indicate that there might be variation in the area of p-nitro-L-phenylalanine residue and might produce new comformational epitopes.The results of MD stimulation will guide the immunogenicity experiments of p-nitro-L-phenylalanine modified proteins.

To investigate whether chemically modified non-anticoagulation heparin derivate (periodate oxidation/borohydride reduction-modified heparin (OR-heparin)) could inhibit high glucose-induced human mesangial cell apoptosis and to explore its possible mechanism.Methods:Mesangial cells were exposed to high glucose or high glucose with OR-heparin for 24 h.Apoptosis was evaluated by Hoechst 33258 staining and Fluorescent activated cell sorting analysis.The expressions of apoptosis-related proteins ( p53,Bcl-2,Bax,cytosolic cytochrome C) were determined by Western blotting.NF-kB translocation was observed under fluorescence microscopy by using Cy3-1abeled antibody.Caspase-3 activity was detected by colorimetry.Results:OR-heparin significantly inhibited high glucose-induced mesangial cell apoptosis and the expression of apoptosis-related proteins.It also blocked NF-kB translocation induced by high glucose.Conclusion:OR-heparin inhibits high glucose-induced mesangial cell apoptosis through inhibiting the expression of apoptosis-related proteins and it may be due to the blockage of the translocation of NF-kB.

Ubiquitous chromatin opening element ( UCOE ) , composed of the promoters of human housekeeping genes, prevents transgene from silencing and produces consistent, stable and high-level gene expression irrespec-tive of the chromosomal integration site. The research studied the influence of different UCOE element parts on antibody expression in CHO cells. UCOE 1. 5 kb from chromobox homolog 3 ( CBX3 ) , UCOE 2. 5 kb from the heterogeneous ribonucleoprotein A2/B1 ( HNRPA2 B1 ) and the whole UCOE 4. 0 kb were inserted into the anti-body light and heavy chain vectors, respectively, and transfected into CHO cells using antibiotics-Zeocin and Blasticidin for pressure selection. Four groups of monoclonal cells were harvested and antibody expression of each group was detected. The monoclonal cells with UCOE 1. 5 kb and UCOE 2. 5 kb increased 1. 5 to 2-fold in the level of antibody expression, wheareas, monoclonal cells with UCOE 4. 0 kb increased 3 to 4-fold. The enhance-ment of two housekeeping promoter genes on antibody expression could stack up.

To optimize Chinese hamster ovary (CHO)expression system and establish a process of screening CHO cell lines with high productivity;neomycin-phosphotransferase (NPT)expressed by the resistance marker gene on the expression vector was mutated with amino acid D at 261 changed to G.After selection by culturing with G418;the survival rate of CHO cells bearing mutant-NPT was significantly lower than that of the cells bear-ing wide type NPT.An enhanced green fluorescent protein (EGFP)was genetically linked to the N terminus of the IgG1 Fc fragment part to generate an EGFP-Fc fusion protein regarded as a report gene;which verified that the resistance of mutant-NPT to G418 was weakened.By comparing fluorescence assay of EGFP intensity in stable transfections after selection with the same concentration of G418 for 3 weeks;mutant-selected pools expressed more exogenous protein than the WT-selected pools.Therefore;the ratio of high producers in a transfected cell population greatly increased.

Aim: To explore the relationship between structure and immunological activity of marine polysaccha-ride YCP,the physicochemical property and immunological activity of the YCP-derived fragment were studied.Methods: YCP was hydrolyzed by α-amylase from human saliva.The hydrolysate was purified to obtain an polysaccharide fragment by gel filtration chromatography.The physicochemical properties of this YCP-derived fragment was characterized by HPLC,FT-IR and TLC.In addition,changes of phagocytic activity,production of reactive nitrogen and macrophage binding were investigated.Results: The relative molecular weight of YCP-de-rived fragment was approximately 6.6 × 10~3.The monosaccharide composition and FT-IR of the YCP-derived frag-ment were identical to YCP.No significant effect of the YCP-derived fragment on NO production and murine mac-rophage phagocyte were observed.And this fragment was not able to compete the binding between YCP and mac-rophages.Conclusion: The remarkable decrease of immunological activity of YCP-derived fragments degraded byα-amylase of human saliva suggests that the complete structure and high molecule weight of YCP are essential for its immuno-modulatory activity.

In order to solve the difficucties of renaturation and immunogenicity of new bifunctional fusion protein GAD,inclusion bodies of GAD were modified by PEG-maleimide.Conformational changes of the modified GAD were compared by circular dichroism and tryptophan fluorescence spectroscopy.The biological activity was verified by oral glucose tolerance test and lipid scavenging.The results showed that PEG-maleimide completed the specific-point modification of GAD,and improved its refolding efficiency.The secondary and tertiary structures of mPEGylated GAD were consistent with that of GAD.PEG-GAD has significant hypoglycemic and lipid-lowering effects (P ＜0.001) with longer half life in vivo and lower immunogenicity (P ＜0.01).This study provides effective strategies for the development of strongly hydrophobic peptide drugs.

To modify uricase with PEG reagent in order to decrease uricase immunogenieity and increase its stability.Methods:The branched PEG of 40 kD was chosen to modify native uricase.The properties of the mod-ified uricase including the stabilities to protease,pH and temperature,in vivo half-life time,as well as the immu-nogenicity were evaluated.The pharmacokinetic profiles of the midofied uricase were studied in mice.Results:It is demonstrated that the conjugation of PEG to lysine residues of Candida utilis uricase resulted in higher tryp-sin resistance.reduced immune response.and prolonged in vivo half-life.PEG modified uricase retained 80% of the enzymatic activity of native uricase.In addition,it was found that half-life in serum of the intravenously injec-ted PEGylated uriease of up to 696 min was longer that that of native uficase of 45 min.Higher plasma drug con-centrations were also reached with dosing of the PEGylated uricase to mice.Furthermore,the binding affinity Was shown to be reduced for the PEG-uricase using ELISA assay.and it was one-eishth that of native uricase.Final-ly,it Was indicated that the PEG uficase induced a delayed immunoresponse in mice following repeated adminis-trations.Conclusion:These findings demonstrate that this chemically modified form of uricase may serve as a potentially effective drug to treat gout patients.

Purpose The research was conducted to evaluate the stability of N-terminal site-specific PEGylated uricase. Methods The enzyme activity is used as an index to evaluate the thermal stability (at 4-80 ℃) , the pH stability, the ability of avoiding the trypsin digestion and half-life in vivo of PEG-uricase, then it is compared with uricase. Results PEGylated uricase is thermally more stable than uricase between 4 ℃ and 60 ℃, but at 70 ℃, the enzyme activity of both PEG-uricase and uricase decreases sharply. In the test of pH stability, the curve of uricase shows an obvious decrease of enzyme activity at 5 .2-6.0 and 9.2-10.0. The behavior of PEG-uricase indicates that the destabilizing was prevented effectively by PEGylation. The test of anti-trypsin digestion suggests that PEG-uricase retains 70% of its enzyme activity,but uricase only 20% ,200 minutes after being reserved in trypsin solution. Stability in vivo indicates that the half-life of PEG-uricase is 1 530 min and uricase, only 45 min. Conclusion PEGylated uricase has improved thermal stability, the pH stability, ability of protecting from trypsin digestion and stability in vivo.

Comparison of rCBF SPECT imaging and clinical visual function of 12 cases with complete homonymous hemianopia (CHH) were taken before and after a course of oriented dynamic color photic stimulation (ODCPS ). It was suggested that ODCPS in patients with CHH was an effective met hod for increasing visual field and improving visual function. Cerebral metabolic patterns of increasing rCBF reflected the mechanism of ODCPS effecting the patients with CHH. The rgtinal- midbrain-occipital visual path way may play an important role in mediating the increase of visual field and restoration of visual function.

Chlamydia psittaci is a causative agent of psittacosis,which can infect a wide range of hosts including birds and humans.However,information regarding C.psittaci infection in pigeons is scarce.In the present study,a total of 399 fecal samples from pigeons were collected from Jilin Province,northeastern China,between March and May 2015,and examined by nested PCR amplification of outer membrane protein A (ompA) gene.The overall Chlamydiosis prevalence was 5.01％ (21/399),with 3.19％ in Changchun City and 9.40％ in Jilin City.Furthermore,breed was the major risk factor associated with Chlamydia infection in pigeon,boiler pigeons had a prevalence of 7.49％,whereas no C.psittaci was detected in racing pigeons.Sequence analysis of the ompA gene revealed that all the identified isolates represented C.psittaci genotype B.Our results firstly indicated the presence of zoonotic C.psittaci in boiler pigeons in Jilin Province,northeastern China,and effective measures should be implemented to reduce the risk of C.psittaci transmission from pigeons to humans.