Development and verification of a detection method for activity of neutralizing antibody in ELISA antibody positive serum of rats immunized with recombinant human interleukin-1 receptor antagonist / 中国生物制品学杂志

@#Objective To develop and verify a method for detecting the activity of neutralizing antibodies in ELISA antibody positive serum of rats immunized with recombinant human interleukin-1 receptor antagonist(rhIL-1Ra). Methods The SD rats were subcutaneously immunized with 3,20 and 100 mg/kg rhIL-1Ra injection respectively,10 rats in each group,half male and half female,twice a day at an interval of at least 4 h between each dose for 13 consecutive weeks. The blood samples were collected from the jugular vein of rats during the administration period and the recovery period. The serum samples were isolated and detected for the antibody titers by ELISA,and the samples positive for rhIL-1Ra antibody were purified by Protein A chromatographic column. Based on,D10G4·1 cells biological activity assay,a method for the detection of neutralizing antibody activity was developed and verified for the specificity,sensitivity and precision. The neutralizing antibody activity of rhIL-1Ra antibody positive serum determined by ELISA was detected by using the developed method.Results With the increase of doses,the serum antibody titers of rats in various dose groups gradually increased,and there were still antibodies in the recovery period,and the titer was still high. Rabbit anti-rhIL-1Ra monoclonal antibody showed obvious neutralizing effect on rIL-1Ra,while rabbit anti-rIFN-2b monoclonal antibody had no dose-effect relationship with rIL-1Ra. The sensitivity of the method was 171. 93 μg/mL;The CVs of precision verification were not more than 20%. The positive antibody sera detected by ELISA all had neutralizing effect on rhIL-1Ra injection,which was consistent with the results detected by ELISA. Conclusion The method developed in this study has good specificity and high sensitivity in the detection of serum neutralizing antibody activity in rats immunized with rhIL-1Ra,which can be used to detect the serum neutralizing antibody activity of animals with rhIL-1Ra repeated administration.

Biochemical characterization of the recombinant schistosome tegumental protein SmALDH_312 produced in E. coli and baculovirus expression vector system

BACKGROUND The heterologous expression of parasitic proteins is challenging because the sequence composition often differs significantly from host preferences. However, the production of such proteins is important because they are potential drug targets and can be screened for interactions with new lead compounds. Here we compared two expression systems for the production of an active recombinant aldehyde dehydrogenase (SmALDH_312) from Schistosoma mansoni, which causes the neglected tropical disease schistosomiasis. RESULTS We produced SmALDH_312 successfully in the bacterium Escherichia coli and in the baculovirus expression vector system (BEVS). Both versions of the recombinant protein were found to be active in vitro, but the BEVS-derived enzyme showed 3.7-fold higher specific activity and was selected for further characterization. We investigated the influence of Mg2+, Ca2+ and Mn2+, and found out that the specific activity of the enzyme increased 1.5-fold in the presence of 0.5 mM Mg2+. Finally, we characterized the kinetic properties of the enzyme using a design-of-experiment approach, revealing optimal activity at pH 7.6 and 41C. CONCLUSIONS Although, E. coli has many advantages, such as rapid expression, high yields and low costs, this system was outperformed by BEVS for the production of a schistosome ALDH. BEVS therefore rovides an opportunity for the expression and subsequent evaluation of schistosome enzymes as drug targets

Gene cloning, protein expression and examination of biological activity of chicken CD40L / 生物工程学报

To obtain chicken CD40L protein, the cDNA was prepared from chicken splenic cells and used as a template to clone and amplify CD40L by PCR. The target gene was cloned into pFastBac vector to construct a pFastBac-chCD40L donor plasmid. Recombinant plasmid was transformed into DH10Bac and recombinant Bacmid-chCD40L was obtained. The Bacmid-chCD40L plasmid was transfected into sf9 insect cells to obtain His-chCD40L protein. In addition, the target gene was cloned into pQM01 vector to construct a pQM01-chCD40L plasmid, recombinant plasmid was transfected into HEK 293T cells to obtain Strep-chCD40L protein. The chCD40L protein was purified by affinity chromatography, and the concentration of purified chCD40L protein was determined to be 0.01 mg/mL. Primary cells were isolated from the bursal tissue of 3-week old SPF chickens, and the chCD40L protein was added to the culture medium to stimulate cells. The chCD40L could bind to CD40 on B cells as examined by Western blotting, indirect immunofluorescence assay and flow cytometry, suggesting that chCD40L protein is biologically active. We successfully obtained chicken CD40L protein of biological activity, which laid the foundation in the in vitro culture of primary B lymphocytes for the isolation and diagnosis of virulent IBDV.

Improved antifungal activity of barley derived chitinase I gene that overexpress a 32 kDa recombinant chitinase in Escherichia coli host

Abstract Agricultural crops suffer many diseases, including fungal and bacterial infections, causing significant yield losses. The identification and characterisation of pathogenesis-related protein genes, such as chitinases, can lead to reduction in pathogen growth, thereby increasing tolerance against fungal pathogens. In the present study, the chitinase I gene was isolated from the genomic DNA of Barley (Hordeum vulgare L.) cultivar, Haider-93. The isolated DNA was used as template for the amplification of the ∼935 bp full-length chitinase I gene. Based on the sequence of the amplified gene fragment, class I barley chitinase shares 93% amino acid sequence homology with class II wheat chitinase. Interestingly, barley class I chitinase and class II chitinase do not share sequence homology. Furthermore, the amplified fragment was expressed in Escherichia coli Rosetta strain under the control of T7 promoter in pET 30a vector. Recombinant chitinase protein of 35 kDa exhibited highest expression at 0.5 mM concentration of IPTG. Expressed recombinant protein of 35 kDa was purified to homogeneity with affinity chromatography. Following purification, a Western blot assay for recombinant chitinase protein measuring 35 kDa was developed with His-tag specific antibodies. The purified recombinant chitinase protein was demonstrated to inhibit significantly the important phytopathogenic fungi Alternaria solani, Fusarium spp, Rhizoctonia solani and Verticillium dahliae compared to the control at concentrations of 80 µg and 200 µg.

Optimization of an Activity Assay of Coprinus Cinereus Peroxidase

ABSTRACT To seek a simple, rapid and sensitive Coprinus cinereus Peroxidase (CIP) activity assay, a convenient one-factor-at-a-time (OFAT) method and a response surface methodology (RSM) were used. The recombinant CIP expressed in Pichia pastoris was purified with the Ni-NTA spin column. Based on the results of catalytic efficiency (kcat/Km) analysis, 2,2'-azinobis (ethylbenzthiazoline -6-sulfonate) (ABTS) was selected as the optimal enzyme substrate. Results of the OFAT method showed that enzymatic reaction performed in 0.1 mol/L sodium acetate (pH 5.0) buffer in a 200-µl reaction mixture containing 0.5 mmol/L ABTS, 10 mmol/L hydrogen peroxide (H2O2), 49.7 ng CIP at 25°C gave an average CIP activity of 88 U/mL. The ABTS and H2O2 concentrations were then further optimized to improve the sensitivity of the assay. To do that, RSM was conducted through central composite design, and a reduced quadratic model with good fit regression equation was generated. ANOVA analysis of this model indicated that the concentrations of ABTS and H2O2 and their interaction had significant impact on the assay sensitivity. The optimal reaction mixture was determined to include an initial ABTS concentration of 0.82 mmol/L 49.7 ng CIP and 16.36 mmol/L H2O2, and the activity under this condition was determined to be 138.89 U/mL.

Effect of sumoylation on the structure and activity of human thymine DNA glycosylase / 上海交通大学学报（医学版）

Objective: To study the effect of sumoylation on the structure, stability and activity of human thymine DNA glycosylase (TDG). Methods: Expression and purification systems were established for obtaining SUMO-1-TDG protein with high purity which can be used for crystal screening and activity detection. Structure of SUMO-1-TDG was solved after crystal screening, diffraction data collection and structure analysis. The change of TDG stability led by sumoylation was detected through a protein thermal shift assay. In addition, an activity assay was applied to investigate the effect of sumoylation on the activity of TDG. Results: A high-resolution structure of SUMO-1-TDG which could clearly describe the interaction between TDG and SUMO-1 was solved. The melting temperature (Tm) value of SUMO-1-TDG increased by about 16℃ and the catalytic activity increased by 9.70%, comparing with TDG protein. Conclusion: SUMO-1 binds to TDG to modify the intermolecular interaction of amino acids near the binding site, and further participates in the regulation of the stability and catalytic activity of TDG protein.

Effect of sumoylation on the structure and activity of human thymine DNA glycosylase / 上海交通大学学报（医学版）

Objective·To study the effect of sumoylation on the structure,stability and activity of human thymine DNA glycosylase (TDG).Methods·Expression and purification systems were established for obtaining SUMO-1-TDG protein with high purity which can be used for crystal screening and activity detection.Structure of SUMO-1-TDG was solved after crystal screening,diffraction data collection and structure analysis.The change of TDG stability led by sumoylation was detected through a protein thermal shift assay.In addition,an activity assay was applied to investigate the effect of sumoylation on the activity of TDG.Results·A high-resolution structure of SUMO-1-TDG which could clearly describe the interaction between TDG and SUMO-1 was solved.The melting temperature ? value of SUMO-1-TDG increased by about 16 ℃ and the catalytic activity increased by 9.70％,comparing with TDG protein.Conclusion·SUMO-1 binds to TDG to modify the intermolecular interaction of amino acids near the binding site,and further participates in the regulation of the stability and catalytic activity of TDG protein.

Rapid and sensitive high-throughput determination method for alanine-dependent transaminase / 中国药科大学学报

@#A new method for determining transaminase activity based on the color change of the reaction solution was established, by using alanine-dependent transaminase VfTA from Vibrio fluvialis JS17 as the research object coupled with pyruvate oxidase and horseradish peroxidase. After the optimization of the conditions, the linear relationship between VfTA activity units and the absorbance at 400 nm was investigated. This method was also applied to determine the activity of commercial transaminase ATA117. The results showed that the detection limit of transaminase VfTA activity was up to 0. 45 U/mL and the detection limit of ATA117 activity was up to 0. 5 U/mL. The transaminase activity could be quickly judged according to the color depth of the reaction solution.

Expression and activity assay of recombinant flap endonuclease 1 / 生物工程学报

Flap endonuclease 1 (FEN1) is an endonuclease that catalyzes invasive reaction. It can be used in signal-amplification reaction-based nucleic acid assay. However, the application of FEN1 is hampered due to the lack of detailed protocols to express and purify the enzyme, and to quantify the enzyme activity. In this paper, the DNA fragment coding the gene of FEN1 from Archaeoglobus fulgidus was synthesized, and inserted into the plasmid of pET24a(+) to express recombinant FEN1 with His-tag. After optimizing the expression, detailed expression protocol of FEN1 was obtained by culturing the recombinant E. coli at 37 ℃ with 200 r/min of shaking for 8 h, followed by inducing with 0.05 mmol/L IPTG at 37 ℃ for 11 h. The purified recombinant FEN1 with the molecular mass of 38 kDa was obtained by Ni-affinity chromatography. Moreover, we developed a accurate quantification method with fluorescence-labelled probes. Finally, the recombinant FEN1 was used in real-time PCR coupled with high specific invader assay for aldh2 gene genotyping to obtain the correct typing results, indicating that the recombinant FEN1 can be used in gene polymorphism detection. We provide a reliable enzyme for developing invasive reaction-based nucleic acid assay.

Expression,cloning and activity assay of active domain of human granzyme A / 中国免疫学杂志

Objective:To clone and express active domain of human granzyme A ( aGzmA ) and detect its biological activity.Methods:Human aGzmA gene was amplified by PCR from the full-length human granzyme A and inserted into prokaryotic ex-pression vector pET24a(+).The constructed recombinant plasmid pET24a-aGzmA was transformed to E.coli BL21(DE3) and induced with IPTG.The expressed product was identified by SDS-PAGE and Western blot.The recombinant protein was purified by the Ni2+affinity column chromatography and the enzyme activity was assayed with BLT substrate.Results: A DNA fragment of 700 bp was amplified by PCR.The recombinant plasmid pET24a-aGzmA identified by enzyme-digesting analysis and sequencing showed that aGzmA gene was inserted into vector plasmid correctly.SDS-PAGE analysis showed that there was a specific protein with a relative molecular mass of about 26 kD.Western blot analysis indicated that the protein could react with mouse anti-His monoclonal antibody specifically.The recombinant protein with high purity could be acquired from the inclusion bodies by the Ni2+ affinity column chromatography and the purified protein had good enzyme activity.Conclusion: The recombinant human granzyme A with good biological activity was prepared successfully.

Activity assay and preservation of S-homocysteine methyltransferase / 国际检验医学杂志

Objective To construct a simple method for the measurement of activity of S-homocysteine methyltransferase (HMT),and explore the best processing condition for HMT and the preservation of HMT.Methods HMT was expressed in pro-karyotic system by using genetic engineering technology,then was purified by using affinity and Sephadex G1 5 chromatography. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE)was performed to identify the physicochemical and bio-logical properties of target protein.Based on the principle of 5 ,5′-disulfide-double (2- nitro benzoic acid)(DTNB)could react with sulfydryl compounds rapidly,the reduction of homocysteine was detect to evaluate the activity of enzyme,then the best processing conditions of HTM were determined.Activity of enzyme,preserved in preservation solution with or without glycerol and preserved under different temperatures,was detected.Activity remaining ratios were detected and compared between HMT preserved in pres-ervation solution with different protective agents of different concentration and preserved by cryodesiccation.Results The purity of recombined HMT was above 95%,with molecular weight of 36 000 and excellent catalytic activity,and the catalytic activity was 2 000 U/mg.The optimum condition for the detection of biological activity was using HEPES buffer of pH 7.4 at 37 ℃ and reac-tion for 25 min.Glycerol could significantly prolong the preserving time of HMT,and half activity of HMT could be remained for six months.The reservation rates of activity of HMT,preserved in preservation solution with mannitol and trehalose,were 104%and 100%,respectively.Conclusion HMT could be obtained through genetic engineering.A simple test method of HMT was es-tablished,and the best processing conditions and preserving methods of HMT were determined,which laid a foundation for clinical application.

Rapid synthesis of biocompatible silver nanoparticles using aqueous extract of Rosa damascena petals and evaluation of their anticancer activity

Objective: To optimize the process parameters involved in the green synthesis of silver nanoparticles (G-SNPs) by aqueous extract of Rosa damascena petals and to evaluate the biocompatibility and anti cancer activity of the synthesized silver nanoparticles against human lung adenocarcinoma (A549). Methods: The process variables that include concentration of extract, mixing ratio of reactants, silver salt concentration and interaction time were analyzed. The compatibility of the G-SNPs was verified by incubating with erythrocytes and the anticancer property of the G-SNPs against A549 cells was performed by MTT assay. Results: Formation of G-SNPs was confirmed by the visual change in the colour of the reaction mixture from pale yellow to brown yellow. Surface plasmon resonance of synthesized G-SNPs was observed at 420 nm; the size of G-SNPs were analyzed by DLS and found to be in the range of (84.00±10.08) nm. Field emission scanning electron microscope and high resolution transmission electron microscopy analysis confirmed that the G-SNPs were fairly spherical. Fourier transform infrared spectroscopy spectroscopy and X-ray diffraction revealed the characteristic peaks of G-SNPs. Energy dispersive X-ray analysis showed a signal of silver around 3 keV. The synthesized G-SNPs exhibited anticancer activity as evidenced by the MTT assay. IC

Usefulness of the Endotoxin Activity Assay to Evaluate the Degree of Lung Injury

PURPOSE: It has been reported that the Pulse Contour Cardiac Output (PiCCO) is very useful mainly in the field of intensive care and treatment to grasp the pathophysiological conditions of pulmonary edema because of its capability of obtaining data such as Pulmonary Vascular Permeability Index (PVPI) and Extra Vascular Lung Water (EVLW). Furthermore, a high degree of usability of various markers has been reported for better understanding of the pathological conditions in cases with septicemia. MATERIALS AND METHODS: The correlation between the cardiorespiratory status based upon the PiCCO monitor (EVLW and PVPI) and inflammatory markers including C reactive protein, procalcitonin (PC), and Endotoxin Activity Assay (EAA) were evaluated in 11 severe cases that required treatment with a respirator in an intensive care unit. RESULTS: The EAA values were significantly higher in patients with abnormal EVLW at 0.46+/-0.20 compared to the normal EVLW group at 0.21+/-0.19 (p=0.0064). In a similar fashion, patients with abnormal PVPI values tended to have higher PC levels at 18.9+/-21.8 compared to normal PVPI cases at 2.4+/-2.2 (p=0.0676). On the other hand, PVPI was significantly higher in the abnormal EAA group at 3.55+/-0.48 in comparison with the normal EAA group at 1.99+/-0.68 (p=0.0029). The abnormal EAA group tended to have higher PVPI values than the normal EAA group. CONCLUSION: The EAA is a measurement method designed to estimate the activity of endotoxins in the whole blood. Our results suggest that the EAA value, which had the greatest correlation with lung disorders diagnosed by the PiCCO monitoring, reflects inflammatory reactions predominantly in the lungs.

Rapid synthesis of biocompatible silver nanoparticles using aqueous extract of Rosa damascena petals and evaluation of their anticancer activity

OBJECTIVE@#To optimize the process parameters involved in the green synthesis of silver nanoparticles (G-SNPs) by aqueous extract of Rosa damascena petals and to evaluate the biocompatibility and anti cancer activity of the synthesized silver nanoparticles against human lung adenocarcinoma (A549).@*METHODS@#The process variables that include concentration of extract, mixing ratio of reactants, silver salt concentration and interaction time were analyzed. The compatibility of the G-SNPs was verified by incubating with erythrocytes and the anticancer property of the G-SNPs against A549 cells was performed by MTT assay.@*RESULTS@#Formation of G-SNPs was confirmed by the visual change in the colour of the reaction mixture from pale yellow to brown yellow. Surface plasmon resonance of synthesized G-SNPs was observed at 420 nm; the size of G-SNPs were analyzed by DLS and found to be in the range of (84.00±10.08) nm. Field emission scanning electron microscope and high resolution transmission electron microscopy analysis confirmed that the G-SNPs were fairly spherical. Fourier transform infrared spectroscopy spectroscopy and X-ray diffraction revealed the characteristic peaks of G-SNPs. Energy dispersive X-ray analysis showed a signal of silver around 3 keV. The synthesized G-SNPs exhibited anticancer activity as evidenced by the MTT assay. IC50 value of G-SNPs was found to be 80 μg/mL.@*CONCLUSION@#The results of the present study suggest that G-SNPs can be synthesized rapidly within first minute of the reaction; they are biocompatible and possess anticancer activity against human lung adenocarcinoma.

Cloning, expression, purification and activity assay of Leucyl-tRNA synthetase from Trypanosoma Brucei / 中国生化药物杂志

Purpose To clone and express Trypanosoma Leucyl-tRNA synthetase (LeuRS) gene and to complete the purification and activity assay of LeuRS. Methods We cloned the LeuRS gene from T. Brucei genomic DNA,and cloned it into pBS-T and then into the expression vector pET21a( + ) .The expression of T. Brucei LeuRS was carried out in E. coli BL21 (DE3) RIPL host by optimizing the expression conditions. The products are purified by His-Bind affinity column and verified by Western blot . Enzymatic activity was detected by isotope labeling. Results A DNA fragment at length of 3.2 kb was amplified. Both restriction analysis and sequencing analysis proved that recombinant plasmid pET21a( + )/LeuRS was correctly constructed. The expressed product contained about 20% of total somatic soluble protein and reached a purity of 85% after purification . It was verified by the Western blot. Enzyme unit per millilitre of purified products was about 72. Conclusion Here we report the successful clone, expression and purification of LeuRS from Trypanosoma Brucei ( T. Brucei) in bacterial host. In addition, we tested its enzymatic activity by isotope labeling.This work would be helpful to the design and in vitro screening of Trypanosoma LeuRS inhibitors.

Alterations of the proteasome in the CA1 neurons after transient ischemia / 中华急诊医学杂志

Objective To investigate the alteration of chaperonine hsp40 and its influence on delayed death of neurons in the CA1 region of hippocampus after transient cerebral ischemia. Method After transient global ischemia for 20 minutes, rat model was made. Following different lengths of reperfusion, all the 28 wistar rats were divided into sham-operation group,4 hour recovery group, 24 hour recovery group and 72 hour recovery group ( n = 7 rats in each group). Immunochemistry and laser scanning confocal microscopy were used to observe the distributional alteration of hsp40 in the neurons. Differential centrifuge and western blot assay were used to analyze the quantitative alteration of hsp40 and its redistribution in the neurons. Results Immunochemistry and laser scanning confocal microscopy showed the progressive reduction of hsp40 occurred at first in the cytosol, then in the nucleus until the death of all the neurons in the CA1 region died. Differential centrifuge and western blot assay showed the level of hsp40 decreased from 1.00 ± 0.21 to 0.23 ± 0.13 ( P ＜ 0.01 ) 24 hours after reperfusion; the quantity of hsp40 in the protein aggregates increased from 1.00±0.18 to 8.61 ± 1.89 (P ＜0.01 =24 h after reperfusion.Conclusions The reduction of hsp40 in the neurons of hippocampus CA1 region is an important role in protein aggregates formation.

Prueba cuantitaiiva para proteasas usando películas fotográficas / Quantitative Protease Assay Using Photographic Films

Se han desarrollado dos métodos para la medición cuantitativa de la actividad proteasa basados en la prueba de la película fotográfica. Una prueba discontinua puede ser implementada mediante la cuantificación de la cantidad de pigmento remanente en la película con cualquier programa de edición de imágenes. La medición continua de la actividad proteasa se puede obtener a través del cambio de absorbancia generado por la liberación de las sales de plata unidas al negativo fotográfico si se cuenta con un espectrofotómetro equipado con una celda con agitación.

Two quantitative protease assays have been developed based on the classic photographic film test. A discontinuous assay can be performed by measuring the amount of pigment remaining in the film with any image editor software. A continuous assay can be implemented by the measuring the release of silver halide salts bonded in the film using a recording spectrophometer equipped with a Peltier Cell.

Gene Coloning, Expression and Activity Assay of Survivin / 中国生物工程杂志

Survivin expresssion in embryo spleen, embryo kidney, embryo liver and in many cancer tissues was determined by RT-PCR, while not in the health liver tissue. Construct the engineered Escherischia coli expressing human survivin and identify the expressed human survivin by Westen-blot. The combination activity of Survivin and RhSmac was determined in vitro. L929 cells transferred with Survivin can survive longer than which transferred with BSA.

Cloning and function analysis of 5′ end flanking sequence of EOLA1 gene / 第三军医大学学报

Objective To construct the ?-gal reporter genes containing the 5′-end flanking of endothelial-overexpressed lipopolysaccharide-associated factor 1 (EOLA1) gene in different sequence lengths and identify the sequence, which regulates the gene expression of EOLA1 by the ?-gal analysis system. Methods The target sequences were amplified by the method of genome walker, and were inserted into the upstream of ?-gal gene located in the ?-gal enhancer vector by the directional clone technique respectively; the regulative sequence was identified by analyzing the ?-gal activities of reconstructed plasmid in ECV304 cells. Results The regions, containing 2 659 bp and 1 951 bp upstreaming from exon 1, significantly stimulated the reporter gene activity as compared with that of the ?-gal control vector in transfected cells. But the region, containing 361 bp upstreaming from exon 1, did not stimulate the reporter gene activity. Conclusion There is an up-regulative element of gene transcription in the region of -361 to -1 951 bp in EOLA1 gene upstream.

Purification and functional assay of recombinant human interleukin 18 / 中国免疫学杂志

Objective:To purify recombinant human interleukin 18(rhIL 18) and perform activity assay of renatured rhIL 18 Methods:The rhIL 18 was purified by molecular sieve chromatography MTT assay and RT PCR method were used in activity assay of rhIL 18 Results:The purity of rhIL 18 was up to 96% The renatured rhIL 18 could enhance the cytotoxicity of NK cells and induce IFN ? gene expression in PBMC Conclusion:The rhIL 18 prepared exerts functional activity and can be applied for further studies