Immunogenicity Studies of Various Experimental Vaccines in Chickens

In this paper, the main objective was to raise chickens’ antibodies against three crucial public health microorganisms: the human immunodeficiency virus-1, Salmonella spp, and Staphylococcus aureus. Immunogens were prepared from the said microorganisms. Chickens were vaccinated either orally or intramuscularly. After a booster immunization, mostly eggs were collected and assess for the presence of specific antibodies. The most important results were the production of a large amount of anti-HIV antibodies in chicken’s eggs, and also the synthesis of anti-protein a antibodies with the ability to inhibit the growth of S. aureus in vitro and to serve as anti-anti-idiotypic antibodies with the capacity of neutralizing the original antigen. Enzyme- linked immune absorbent assays detected the presence of these antibodies as anti-Salmonella antibodies that were critical in reducing the bacterial load in the stomach and caeca compared with a control group. The vaccines were effective and safe, but more laboratory work, and economics have to be carried out to start a human trial.

Cloning, expression and purification of fructose-2, 6-bisphosphatase gene CpF2KP in papaya / 生物工程学报

Papaya, which is mainly cultivated in the southeastern region of China, is one of the four famous fruits in Lingnan. It is favored by people because of its edible and medicinal value. Fructose-6-phosphate, 2-kinase/fructose-2, 6-bisphosphatase (F2KP) is a unique bifunctional enzyme with a kinase domain and an esterase domain that catalyzes the synthesis and degradation of fructose-2, 6-bisphosphate (Fru-2, 6-P2), an important regulator of glucose metabolism in organisms. In order to study the function of the gene CpF2KP encoding the enzyme in papaya, it is particularly important to obtain the target protein. In this study, the coding sequence (CDS) of CpF2KP, with a full-length of 2 274 bp, was got from the papaya genome. The amplified sequence of full-length CDS was cloned into the vector PGEX-4T-1 which was double digested with EcoR I and BamH I. The amplified sequence was constructed into a prokaryotic expression vector by genetic recombination. After exploring the induction conditions, the results of SDS-PAGE showed that the size of the recombinant GST-CpF2KP protein was about 110 kDa. The optimum IPTG concentration and temperature for CpF2KP induction were 0.5 mmol/L and 28 ℃, respectively. The purified sin[A1] gle target protein was obtained after purifying the induced CpF2KP protein. In addition, the expression level of this gene was detected in different tissues, and showed that the gene was expressed at the highest level in seeds and the lowest in pulp. This study provides an important basis for further revealing the function of CpF2KP protein and studying the involved biological processes of this gene in papaya.

The therapeutic effect of human thioredoxin on ulcerative colitis in mice / 药学学报

This study was designed to obtain recombinant human thioredoxin (rhTXN) by gene cloning and prokaryotic expression, and evaluated its therapeutic effect in the mouse ulcerative colitis (UC) model induced by dextran sulfate sodium (DSS). The human thioredoxin gene TXN was cloned from the cDNA of Jurkat cells. The recombinant expression plasmid pCold TF-rhTXN was constructed by restriction enzyme digestion. After expression in E. coli BL21 (DE3), recombinant human thioredoxin was purified by a nickel column. Intact rhTXN recombinant protein was obtained after removal of the fusion partner-tag by enzyme digestion and the activity of disulfide reductase was detected by the insulin reduction method. The animal experiments in this study were performed in accordance with the ethical guidelines of the Laboratory Animal Welfare Ethical Review Committee of Nanjing University. Experiment ulcerative colitis was induced by providing mice with sterilized drinking water which contained 3% DSS. rhTXN was injected intraperitoneally. The therapeutic effect was studied by weight change, colon length and HE (hematoxylin and eosin) stained sections. In vivo imaging was used to study the targeting of rhTXN to DSS mice. The GSE107499 data set of GEO database was used to screen the hub genes at the lesional sites of UC and study the correlation with TXN. The experimental results showed that rhTXN was successfully expressed and purified with disulfide reductase activity. rhTXN (100 μg·kg-1) had a significant therapeutic effect on maintaining the weight change of mice (P = 0.000 5) and reducing intestinal injury (P < 0.000 1), and had a colon targeting effect on DSS mice. In GSE107499 data set, TXN in inflammatory sites of UC patients was significantly down regulated (P < 0.01) and negatively correlated with hub gene CD40 (P < 0.01) and positively correlated with hub gene fibronectin 1 (FN1) (P < 0.01). In this study, biologically active rhTXN was successfully prepared and proved to have a promising therapeutic effect on the DSS mouse model, and TXN gene was significantly correlated with the UC hub genes CD40 and FN1.

Prokaryotic expression of a recombinant protein of adeno-associated virus capsid conserved regions and preparation of its polyclonal antibody / 南方医科大学学报

OBJECTIVE@#To express and purify the antigenic peptide of adeno-associated virus (AAV) capsid conserved regions in prokaryotic cells and prepare its rabbit polyclonal antibody.@*METHODS@#The DNA sequence encoding the conserved regions of AAV capsid protein was synthesized and cloned into the vector pET30a to obtain the plasmid pET30a-AAV-CR for prokaryotic expression and purification of the conserved peptides. Coomassie blue staining and Western blotting were used to identify the AAV conserved peptides. Japanese big ear white rabbits were immunized with AAV conserved region protein to prepare polyclonal antibody, with the rabbits injected with PBS as the control group. The antibody titer was determined with ELISA, and the performance of the antibody for recognizing capsid protein sequences of AAV1-AAV10 was assessed with Western blotting and immunofluorescence assay.@*RESULTS@#The plasmid pET30a-AAV-CR was successfully constructed, and a recombinant protein with a relative molecular mass of 17000 was obtained. The purified protein induced the production of antibodies against the conserved regions of AAV capsid in rabbits, and the titer of the purified antibodies reached 1:320 000. The antibodies were capable of recognizing a wide range of capsid protein sequences of AAV1-AAV10.@*CONCLUSION@#We successfully obtained the polyclonal antibodies against AAV capsid conserved region protein from rabbits, which facilitate future studies of AAV vector development and the biological functions of AAV.

Preparation of purified proteins from fresh Pheretima and their inhibitory effect against pulmonary fibrosis in mice / 南方医科大学学报

OBJECTIVE@#To develop a convenient method for rapid purification of fresh Pheretima proteins and assess the inhibitory effect of these proteins against pulmonary fibrosis.@*METHODS@#The crude extract of fresh Pheretima was obtained by freeze-drying method and then purified by size exclusion chromatography. The composition of the purified proteins was analyzed by mass spectrometry. MRC-5 cells were treated with 5 ng/mL TGF-β1 alone (model group) or in combination with SB431542 (2 μmol/L) or the purified proteins (13.125 μg/mL), and the cytotoxicity of purified proteins and their inhibitory effects on cell proliferation were detected with CCK8 assay. Flow cytometry was used to detect the changes in cell apoptosis, and the cellular expressions of α-SMA, Vimentin, E-cadherin, collagen I, Smad2/3 and P-Smad2/3 were detected using RT-PCR and Western blotting. In the animal experiment, adult male C57BL/6 mice were subjected to intratracheal instillation of bleomycin followed by treatment with the purified proteins (5 mg/mL) for 21 days, after which HE and Masson staining was used to observe the pathological changes in the lung tissue of the mice.@*RESULTS@#We successfully obtained purified proteins from fresh Pheretima protein by size exclusion chromatography. Treatment with the purified proteins significantly inhibited TGF-β1-induced proliferation of MRC-5 cells (P < 0.01), reduced the cellular expressions of α-SMA, Vimentin and collagen I (P < 0.001 or P < 0.01), increased the expression of E-cadherin (P < 0.01), and inhibited the expressions of Smad2/3 and P-Smad2/3 (P < 0.001 or P < 0.01). In male C57BL/6 mice models of bleomycin-induced pulmonary fibrosis, treatment with the purified proteins obviously reduced the number of inflammatory cells and fibrotic area in the lungs.@*CONCLUSION@#The purified proteins from fresh Pheretima obtained by size exclusion chromatography can inhibit pulmonary fibrosis in mice by regulating the TGF-β/ Smad pathway.

Desenvolvimento de jogos didáticos para o ensino de Bioquímica / Development of educational games for biochemical education

A Pesquisa de Educação em Bioquímica investiga aspectos relacionados ao ensino-aprendizagem, principalmente no ensino superior. Dentre as alternativas às aulas expositivas, os jogos didáticos apresentam-se como recursos que promovem a elaboração de estratégias, a tomada de decisão, o intercâmbio de informações entre os pares, etc. Estas características configuram os jogos didáticos como ferramentas importantes para a aprendizagem ativa. O objetivo deste trabalho foi desenvolver jogos didáticos para o ensino de bioquímica. Para elaboração dos objetos de ensino, utilizou-se uma estratégia baseada em três etapas: definição das características educativas, elaboração do design conceitual e desenvolvimento do jogo e pré-avaliação. A partir da gravação e transcrição de áudio de algumas partidas dos jogos e, quando possível, por questionários, foram feitas avaliações preliminares a fim de inferir o potencial educacional dos recursos didáticos. Dois jogos didáticos foram desenvolvidos: "Pura Proteína! Uma Experiência no Laboratório de Bioquímica" e "Perfil Lipídico". O objetivo principal do primeiro jogo foi desenvolver competências de planejamento e teste de hipóteses cientificas a partir da simulação de experimentos de purificação de proteínas. A construção deste material foi fundamentada em preceitos teóricos do Ensino por Investigação. Pura Proteína é constituído por um tabuleiro e cerca de 4000 cartas e fichas. Os jogadores, ao início do jogo, recebem um desafio: obter uma determinada quantidade de uma proteína específica, purificada a partir de uma solução composta por uma mistura de proteínas. Para a consecução desse objetivo os estudantes recebem informações sobre alguns métodos de purificação de proteínas mais utilizados. Para vencer, os participantes devem combinar métodos de forma eficaz a obter, antes dos outros jogadores, a quantidade de proteína pura desejada. O jogo foi aplicado com estudantes de graduação em Biomedicina e foi feita uma análisedo processo investigativo que empregavam. Verificou-se que o jogo foi capaz de promover a elaboração de um plano de trabalho, tomada de decisão a partir de argumentações, teste e verificação de hipóteses, ao mesmo tempo em que promovia a diversão. O segundo jogo desenvolvido foi "Perfil Lipídico", por meio do qual pretendeu-se explorar a diversidade das estruturas de lipídeos e os grupos químicos que os compunham. O jogo dispõe de quinze lipídeos, distribuídos em ácidos graxos e lipídeos complexos e, para vencer, os jogadores devem descobrir a identidade de um lipídeo a partir de dicas e desenhar sua estrutura. A prática do jogo permitiu diagnosticar pequenos erros conceituais dos jogadores, revelados ao desenhar as estruturas. Ao responder um questionário, os participantes atestaram que este jogo era motivador, de fácil aplicação em sala de aula e que permitiu revisar a estrutura dos lipídeos. Os dois jogos, com objetivos educacionais muito diferentes, foram desenvolvidos a partir de uma estratégia rigorosa, que permitiu o equilíbrio entre as funções lúdicas e educativas, necessário para o sucesso desta estratégia em sala de aula. Em razão da pandemia da COVID-19, os jogos não puderam ser aplicados com o público apropriado, o que impediu uma avaliação mais robusta do potencial educacional. Os dados coletados, no entanto, forneceram indícios de que ambos os objetos de ensino são eficazes para promover o aprendizado de bioquímica, ao mesmo tempo que a diversão própria do jogo

Biochemical Education research focuses on aspects related to teaching and learning, mostly in higher education. Among several methodological alternatives to traditional classes, educational games are tools that promote the development of problem-solving strategies, decision-making, peer exchange of information, etc. These features make educational games valuable tools for active learning. The main goal of the work herein presented was to develop educational games for Biochemical Education. For this purpose, a three-step based strategy was designed: definition of educational features, conceptual game design and development and evaluation. To assess educational potential, qualitative data were obtained by recording and transcribing audio captured during plays, and, when possible, questionnaires were applied. Two educational games were developed: "Pure Protein! An Experiment in the Biochemistry Lab" and "Ten Questions - Lipids". The main learning purpose of the first game was to develop skills in planning and testing scientific hypotheses through a simulation of a protein purification experiment. The game development was based on an Inquirybased learning approach. Pure Protein is a board game set-up with ca. 4000 cards. Players are challenged to obtain an amount of a specific protein, purified from a protein solution. To achieve this goal, students receive general information about common methods used to purify proteins. To win, contestants should efficiently combine methods to obtain the needed protein before their adversaries. The game was applied to Biomedicine undergraduate students, and an analysis of the inquiry process they went through was done. It was verified that the game promotes elaboration of a working plan, decision-making supported by arguments, testing and verifying hypotheses while being a fun and enjoyable activity. The second game is called "Ten Questions - Lipids", by which we intended to explore the structural diversity of lipids and the chemical groups in their composition. The game is based on fifteen molecules, ranging from fattyacids to complex lipids. The goal is to figure out the identity and the structure of a given lipid, using clues given throughout the gameplay. The game application allowed us to assess players conceptual mistakes revealed by their drawings of chemical structures. In questionnaire answers, students stated that the game was motivating, suitable for the classroom and that it promoted the review of lipid structures. Both games, with different learning objectives, were developed using a rigorous strategy, which enables the balance between the ludic and educational functions needed to achieve educational game success. Due to the COVID-19 pandemic, the games werent properly evaluated with different, larger groups. Nevertheless, the collected data suggest that the teaching objects are efficient both in promoting biochemical learning and fun

Purification and activity of anti-PD-L1&CXCR4 bispecific nanobody / 中国药科大学学报

@#Targeted programmed death-ligand 1 (PD-L1) and CXC chemokine receptor type 4 (CXCR4), gene sequences encoding anti-PD-L1 nanobody and anti-CXCR4 nanobody were cloned into the pET-22b (+) vector to construct recombinant expression plasmid of anti-PD-L1&CXCR4 bispecific nanobody, which was connected with 6 × His tag and transformed into E.coli BL21 (DE3). The expressed proteins were then found to exist as a soluble form in the supernatant of bacterial lysate after induction of IPTG.Three purification methods were used to obtain the target protein in order to improve the yield and purity of the bispecific nanobody.The bacterial supernatant was separated and purified by His Trap FF affinity chromatographic column.The target protein output could exceed 1 mg/L, and the product purity could reach up to 97%.Besides, the anti-PD-L1&CXCR4 bispecific nanobody shows a specific binding ability to two antigens on the cell surface, enhancing the cytotoxicity of IL-2 activated human peripheral blood mononuclear cells (PBMC) to tumor cell line AsPC-1, which lays the foundation for further evaluation of its drug efficacy in vivo.

Rapid Enrichment and Activity Research of Antithrombotic Proteins from Pheretima vulgaris / 中国实验方剂学杂志

Objective:A strong antithrombotic protein component， named PvQ， was purified and enriched from total protein of <italic>Pheretima vulgaris</italic>，<italic> </italic>a<italic> </italic>traditional Chinese medicine. Moreover， we evaluated its fibrinolytic and anticoagulant activity， and expected to provide reference for the research on antithrombotic substances of Pheretima. Method:A rapid <italic>in</italic> <italic>vitro</italic> activity-oriented separation combined with the AKTA-Pure protein purification system conducted on <italic>P. vulgaris</italic>. Meanwhile， the fibrinolytic and anticoagulant activities of PvQ were measured by fibrin plate method and fibrinogen-thrombin time （Fibg-TT） method. And the <italic>in vitro</italic> thrombolysis assay was used for evaluating the lysis ability of PvQ to thrombus. Then the stability of PvQ was also analyzed for its anticoagulant activity at different pH and temperature. Result:The PvQ was successfully enriched and its activity was determined to have significant fibrinolytic and anticoagulant activities. And the result of <italic>in vitro</italic> thrombolysis assay revealed that PvQ could hydrolyze more than 80% of thrombus after 5 h of incubation at 37 ℃. In addition， the changes of temperature and pH had significant effects on antithrombotic activity， and this study showed that PvQ was rapidly inactivated at ≥60 ℃ or in acidic conditions （pH<7）. While， the activity of PvQ was unaffected or less affected at ≤50 ℃ and under alkaline conditions. Conclusion:A feasible preparation method of PvQ is established， and it can affect fibrin and fibrinogen at the same time， thus exerting a dual fibrinolytic effect and possessing significant fibrinolytic and anticoagulant activities. It provides a scientific interpretation for the treatment of thrombotic diseases by PvQ and a reference for the development of antithrombotic protein products of Pheretima.

Prokaryotic expression, protein purification and functional verification of human homotypic fusion and vacuole protein sorting complex subunit / 生物工程学报

Homotypic fusion and vacuole protein sorting(HOPS) is a protein complex consisting of VPS11, VPS16, VPS18, VPS33, VPS39, VPS41 and regulates membrane transport in vivo through membrane fusion mechanisms. The evidence suggests that HOPS complex as a fusion factor, facilitates autophagosome-lysosome fusion. To determine whether the HOPS complex directly interacts with the autophagic SNARE protein STX17 in vitro, the coding sequence of the six genes were amplified from the existing plasmids by PCR, and then ligated to the prokaryotic expression vector pGEX 4T-1-GST or pET-His-NusA. After identification through colony PCR and DNA sequencing, 6 recombinant plasmids were constructed and transferred into Escherichia coli BL21 (DE3). The recombinant proteins were purified by glutathione sepharose 4B and nickel column. We used the tobacco etch virus protease to cut off the GST-tag or His-NusA-tag, to obtain HA-VPS11 protein of about 105 kDa, Flag-VPS16 protein of about 97 kDa, HA-VPS18 protein of about 108 kDa, Flag-VPS33 protein of about 70 kDa, HA-VPS39 protein of about 97 kDa, and Flag-VPS41 protein of about 98 kDa. The function of the purified proteins was verified by in vitro glutathione S-transferases pull-down assay, confirming that autophagic SNARE protein STX17 interacted directly with HOPS components. Our findings provide experimental basis to further study the function and mechanism of HOPS complex in the process of autophagosome-lysosome fusion.

Prokaryotic expression, purification and functional identification of epidermal pattern factors in Arabidopsis thaliana / 生物工程学报

Stomatal density is important for crop yield. In this paper, we studied the epidermal pattern factors (EPFs) related to stomatal development. Prokaryotic expression vectors were constructed to obtain EPFs. Then the relationship between EPFs and hydrogen sulfide (H2S) was established. First, AtEPF1, AtEPF2 and AtEPFL9 were cloned and constructed to pET28a vectors. Then recombinant plasmids pET28a-AtEPF1, pET28a-AtEPF2 and pET28a-AtEPFL9 were digested and sequenced, showing successful construction. Finally, they were transformed into E. coli BL21(DE3) separately and induced to express by isopropyl β-D-galactoside (IPTG). The optimized expression conditions including IPTG concentration (0.5, 0.3 and 0.05 mmol/L), temperature (28 °C, 28 °C and 16 °C) and induction time (16 h, 16 h and 20 h) were obtained. The bands of purified proteins were about 18 kDa, 19 kDa and 14.5 kDa, respectively. In order to identify their function, the purified AtEPF2 and AtEPFL9 were presented to Arabidopsis thaliana seedlings. Interestingly, the H2S production rate decreased or increased compared with the control, showing significant differences. That is, EPFs affected the production of endogenous H2S in plants. These results provide a foundation for further study of the relationship between H2S and EPFs on stomatal development, but also a possible way to increase the yield or enhance the stress resistance.

Cloning and expression analysis of 2-oxoglutarate-dependent dioxygenase from Schisandra chinensis / 药学学报

The 2-oxoglutarate-dependent dioxygenase (2-ODD) gene is regarded as the key enzyme gene involved with aryl naphthalene lignan-podophyllotoxin synthesis. To study the expression pattern and function of the Sc2-ODD gene, a full-length cDNA of the gene was cloned. Bioinformatic analysis, the expression pattern, and prokaryotic expression and purification were implemented. The open reading frame of Sc2-ODD gene was 1 077 bp and encoded 358 amino acids with a molecular weight of 40.16 kD. The Sc2-ODD protein contained the conserved 2OG-FeII-oxy sequence of the 2-ODD protein. The results of phylogenetic analysis revealed that Sc2-ODD is most closely related to Corchorus olitorius 2-ODD. qRT-PCR results showed that Sc2-ODD expression displayed obvious up-regulation at the fruit-swelling stage, then down-regulation in the fruit-coloring period. The Sc2-ODD gene was cloned into the bacterial expression vector pGS21T, the recombinant Sc2-ODD protein was expressed in Escherichia coli Rosetta (DE3) cells and the fusion protein was obtained and purified by GST fusion protein purification technology. This study will lay a foundation for further research on the function and expressional regulation of the Sc2-ODD gene in the aryl naphthalene lignans biosynthesis pathway, and also provides a scientific basis for improving the lignan content and the medicinal quality of Schisandra chinensis using plant genetic engineering.

Purification and physicochemical characterisation of Aspergillus niger USM F4 β-mannanase

Aims@#This present study focused on purification of fungal β-mannanase produced by Aspergillus niger USM F4 and also physicochemical characterisation of the purified enzyme.@*Methodology and results@#The purified β-mannanase with a molecular mass of ~47.4 kDa was demonstrated on SDSPAGE gel. The enzyme signified a purification degree of 4-fold, with final specific activity of 196.42 U/mg. It reached an optimum catalytic activity at pH 4.0 and 60 °C. The thermal stability of the enzyme was up to 70 °C and maintained the 50% activity after 30 min at 80 °C. Meanwhile, the pH stability was in the range of pH 3.0-9.0 and a 30 min half-life at pH 10.0. All chemical substances manifested an inhibitory effect on purified β-mannanase, with SDS (28.16 ± 0.05% residual activity) as the strongest inhibitor, followed by cupric ion (Cu2+) (49.51 ± 0.09% residual activity). As a whole, the enzyme displayed a substrate specificity in the order of locust bean gum (LBG) > carboxymethylcellulose > soluble starch > xylan from oat spelt > α-cellulose. Its preference for LBG has generated the Km and Vmax values of 0.20 mg/mL and 9.82 U/mL, respectively.@*Conclusion, significance and impact of study@#The outcomes of our study offer potential for use at industrial scales, particularly in the oligosaccharides production that involve acid-related activity, wide-ranging temperature and pH stability.

Expression and purification of the transcription factor StMsn2 from Setosphaeria turcica in Escherichia coli

Background: In Saccharomyces cerevisiae, Msn2, which acts as a key transcription factor downstream the MAPKHOG cascade pathway, also regulates the expression of genes related to stress responses. However, little is known about the regulation mechanisms of the transcription factor in Setosphaeria turcica. Results: In this study, a zinc finger DNA-binding protein, designated as StMSN2, was cloned from S. turcica. Sequencing results showed that StMSN2 had a 1752 bp open reading frame (ORF), which was interrupted by an intron (135 bp) and encoded a putative 538-amino acid protein. Phylogenetic analysis further revealed that StMsn2 was more closely related to Msn2 of Aspergillus parasiticus. StMSN2 was cloned into the pET-28a vector with His (Histidine) tags and induced with 1 mM IPTG (isopropyl-ß-D-thiogalactoside) at 37°C. The recombinant His-tagged StMsn2 was purified, and a band of size approximately 58.8 kDa was obtained. The high specificity of the polyclonal antibody Msn2-2 was detected with the StMsn2 protein from S. turcica and prokaryotic expression system, respectively. Conclusions: A new gene, named StMSN2, with 1617 bp ORF was cloned from S. turcica and characterized using bioinformatics methods. StMsn2 was expressed and purified in a prokaryotic system. A polyclonal antibody, named Msn2-2, against StMsn2 with high specificity was identified.

Tandem expression, purification and biological activity of recombinant multimeric β-defensin130 in Escherichia coli / 生物工程学报

To improve and broaden the antimicrobial activity of β-defensin130, 3 copies of β-defensin130 encoding sequences were synthesized and cloned into pET28a (+) expression vector, and expressed in Escherichia coli BL21 (DE3) as a 25 kDa soluble protein. The affinity purified 3×β-defensin 130 displayed antimicrobial activity against not only Gram-positive strains including Staphylococcus aureus (ATCC 25923) (45 μg/mL) and Listeria monocytogenes (ATCC 221633) (80 μg/mL) but also Gram-negative strains. Furthermore, the antimicrobial activity of β-defensin130 was not affected by temperature, pH and proteinase digestion. In addition, E. coli-derived 3×β-defensin130 was not toxic to HEK 293 cells and showed a relatively low hemolytic activity against rabbit erythrocytes. Our study proves 3×β-defensin130 expressed in E. coli is stable, non-cytotoxic and low-hemolytic active with great potential as alternative antibiotics.

Prokaryotic expression of ATP5B and preparation and identification of its monoclonal antibody / 吉林大学学报(医学版)

Objective:To construct and identify the monoclonal antibody of ATP synthase beta subunit (ATP5B) with high purity, and to lay foundation for further study.Methods:The ATP5Bgene was amplified by PCR and cloned into the pET28avector and transformed into E.coli BL21 (DE3) .The protein expression was induced by IPTG and then the fusion protein was purified by nickel affinity chromatography column.The protein purity was detected by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) .Three female Balb/C mice were immunized with purified fusion protein and the tail vein blood was taken to detect the titer of ATP5Bantibody by indirect enzyme-linked immunosorbent assay (ELISA) .The spleen cells from the immunized mice with the highest serum titer were mixed with the SP2/0cells to establish the hybridoma cells and the fused cells were screened by indirect ELISA and monoclonally cultured.Karyotype analysis were performed in the positive cells.The hybridoma cells were intraperitoneally injected into 12weeks old BALB/C mice to estabilish the ascites models.The titer of ascites was detected by indirect ELISA.The purity of the antibody was detected by SDS-PAGE.The antibody subtype was detected by ELISA.Results:After PCR amplification, a specific band of 1 455bp was obtained, and the pET28aempty vector was ligated to obtain a recombinant pET28a/ATP5Bvector.The target protein was expressed in the IPTG-induced bacteria solution;the SDS-PAGE results showed that the protein band was found at51 000.The indirect ELISA results showed that the serum titer of the venous blood of immunized mice was up to1:64 000.In karyotype analysis, the total number of chromosomes in hybridoma cells was about the sum of myeloma cells and normal mouse spleen cells.The mouse ascites was prepared with the hybridoma cell line, and the highest titer of the antibody was 1:240 000.The subtype of the monoclonal antibody produced by the hybridoma cells was IgG1.Conclusion:The monoclonal antibody against ATP5Bprotein is successfully prepared by cloning, expressing and purifying the recombinant protein.

Prokaryotic expression of ATP5B and preparation and identification of its monoclonal antibody / 吉林大学学报(医学版)

Objective: To construct and identify the monoclonal antibody of ATP synthase beta subunit (ATP5B) with high purity, and to lay foundation for further study. Methods: The ATP5B gene was amplified by PCR and cloned into the pET28a vector and transformed into K. coli BL21 (DE3). The protein expression was induced by IPTG and then the fusion protein was purified by nickel affinity chromatography column. The protein purity was detected by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Three female Balb/C mice were immunized with purified fusion protein and the tail vein blood was taken to detect the titer of ATP5B antibody by indirect enzyme-linked immunosorbent assay (ELISA). The spleen cells from the immunized mice with the highest serum titer were mixed with the SP2/0 cells to establish the hybridoma cells and the fused cells were screened by indirect ELISA and monoclonally cultured. Karyotype analysis were performed in the positive cells. The hybridoma cells were intraperitoneally injected into 12 weeks old BALB/C mice to estabilish the ascites models. The titer of ascites was detected by indirect ELISA. The purity of tlie antibody was detected by SDS-PAGE. The antibody subtype was detected by ELISA. Results: After PCR amplification, a specific band of 1 455 bp was obtained, and the pET28a empty vector was ligated to obtain a recombinant pET28a/ATP5B vector. The target protein was expressed in the IPTG-induced bacteria solution; the SDS-PAGE results showed that the protein band was found at 51 000. The indirect ELISA results showed that the serum titer of the venous blood of immunized mice was up to 1: 64 000. In karyotype analysis, the total number of chromosomes in hybridoma cells was about the sum of myeloma cells and normal mouse spleen cells. The mouse ascites was prepared with the hybridoma cell line, and the highest titer of tlie antibody was 1 5 240 000. The subtype of the monoclonal antibody produced by the hybridoma cells was IgGl. Conclusion: The monoclonal antibody against ATP5B protein is successfully prepared by cloning, expressing and purifying the recombinant protein.

Establishment of prokar yotic expression system of autoantigen human bactericidal/permeability-incre-asing fold-containing B1 / 中华风湿病学杂志

Objective To establish a prokaryotic expression system of interstitial lung disease associated autoantigen human bactericidal/permeability-increasing fold-containing B1 (BPIFB1), providing tools for the study on its function in immune responese. Methods The coding region of BPIFB1 gene was amplified with specific primers from recombinant pGEM-C20ORF114 plasmid and cloned into the pET28a-MBP-His and pGEX-5X-1 vectors. The recombinant pET-BPIFB1-MBP-His and pGEX-BPIFB1-GST plasmids were transfected into Top10 cells. The positive clones were selected and sequenced. The correct clones of pET-BPIFB1-MBP-His and pGEX-BPIFB1-GST were transfected into prokaryotic expression strain Rosetta (DE3) and induced by Isopropyl β-D-Thiogalactoside (IPTG). The expression of recombinant BPIFB1 fusion protein was analyzed by SDS-PAGE and Western blotting, and purified by urea modified and renaturation and affinity chromatography of nickel NTA-resin. Results The polymerase chain reaction (PCR) produced specific product with the molecular weight equivalent to that of BPIFB1. The recombinant pET-BPIFB1-MBP-His and pGEX-BPIFB1-GST plasmids were cloned by double restriction enzyme digestion and ligation and confirmed by sequencing. The SDS-PAGE result showed that both BPIFB1-MBP and BPIFB1-GST fusion proteins were mainly expressed in the form of inclusion bodies. The Western blotting result revealed that the recombinant BPIFB1-MBP-His protein could be recognized by Anti-6 ×His antibody. The purified soluble BPIFB1-MBP fusion protein was obtained by urea denaturation, affinity chromatography of nickel NTA-resin and then renaturation after purification. Conclusion The BPIFB1 prokaryotic expression system is established by construct recombinant plasmid pET-BPIFB1-MBP-His, and an approach of renaturation after nickel resin affinity purification in denatured condition.

Prokaryotic expression,purification and identification of low-toxic staphylococcal enterotoxin A with D227A mutation / 中国免疫学杂志

Objective:To obtain recombinant D227A mutation Staphylococcal enterotoxin A protein(rSEAD227A) with low toxicity but still retain its immunological activity and high purity. Methods: The SEA gene containing D227A mutation was cloned by PCR. By constructing pET44a-SEAD227Avector and transfecting the expression strain Rosetta, inclusion bodies were solubilized with guanidium hydrochloride and refolded by gradient dialysis;proteins were purified using StrepⅡ affinity chromatography,and identified by Western blot and high performance liquid chromatography-mass spectrometry(LC-MS/MS). Results: The D227A mutation of SEA was cloned and the expression system of Rosetta-rSEAD227Awas constructed. The purified rSEAD227Aprotein was obtained by refolding with gradient dialysis and affinity purification. LC-MS/MS analysis confirmed that the tryptic digested rSEAD227A peptide sequences matched the sequences of SEA in the database. Conclusion: The rSEAD227A protein in high purity was obtained,which provided the ex-perimental basis for further basic research and clinical application of SEA.

Prokaryotic expression and purification of His-tagged-STAT4 (565-748 amino acid) fusion protein / 中国免疫学杂志

Objective:To construct His-tagged peptide of human STAT4 (565-748 amino acid) expression vector and induce its expression in Escherichia coli,followed by purification.Methods:STAT4 gene fragment encoding C-terminal peptide of 565-748 amino acid was amplified by PCR using pEGFP-STAT4 as the template.The PCR product was inserted into prokaryotic expression vector pET-28a and was transformed into component E.coli BL21 cells.By isopropyl-β-D-thiogalactoside(IPTG) induction,fusion protein was found to be expressed in the inclusion body and was denatured by using the urea denaturation buffer followed by renaturation and purifi-cation.Finally the purified protein was confirmed by Western blot.Results:The STAT4 truncated gene encoding 565-748 amino acids peptide was amplified by PCR and inserted into pET-28a vector.After the recombined plasmid was transformed into component BL21, the His-tagged-STAT4 (565-748 amino acids) fusion protein was induced and obtained after denaturation,refolding,purification and dialysis.Conclusion:The eukaryotic expression vector containing the truncated human STAT4 gene encoding 565-748aa peptide has been successfully constructed and the fusion protein was obtained.

Effects of HIV-1 Tat derived from central nervous system of a HIV-associated dementia patient on the activity of human umbilical vein endothelial cells / 中华实验和临床病毒学杂志

Objective@#BG-derived HIV-1 Tat protein from an HIV-associated dementia (HAD) patient was expressed in E. coli BL21(DE3) and purified in order to research the effects on human umbilical vein endothelial cells (HUVECs) activity.@*Methods@#The recombinant plasmid pGEX-KG-tat with HIV-1 tat stored in our laboratory was amplified by PCR. The PCR product was cloned into pET-32a-tat. The recombinant plasmid pET-32a-tat was transfected into E. coli, and Tat protein was expressed in BL21(DE3), which was induced by IPTG. Then it was purified by Ni-chelating chromatography column and gel filtration preloaded column, and identified by SDS-PAGE and Western blot(WB). The concentration was determined by BCA Kit. Different concentrations of Tat were added into HUVECs to detect their effects on cell activity by cck-8.@*Results@#The Tat with high purity was efficiently expressed in BL21 (DE3) and obtained by using the Ni-chelating chromatography column and gel filtration preloaded column. The concentration was 0.47 mg/ml by using BCA Kit. As the concentration of Tat increased, HUVECs activity decreased. There was no significant difference in cells viability between negative control with 100 ng/ml and 200 ng/ml group (P>0.05). There was significant difference in cells viability between negative control with 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group (P<0.05). But the difference between 300 ng/ml, 400 ng/ml, 500 ng/ml and 1000 ng/ml group was not statistically significant (P>0.05).@*Conclusions@#The HIV-1 Tat with biological activity was efficiently expressed in BL21 (DE3), and the activity of HUVECs was significantly decreased when the concentration reached 300 ng/ml.