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@#Objective To prepare murine and rabbit polyclonal antibodies against rabies virus(RV) matrix(M) protein and compare their reactivity.Methods The prokaryotic expression vector pET-28a-M was constructed by using the cDNA of cells infected with RV CVS-11 strain as template,then transformed into E.coli BL21(DE3),and the induced by IPTG to express M protein.After nickel column affinity chromatography and dialysis renaturation,female BALB/c mice and New Zealand white rabbits were immunized with the M protein,and the whole blood was taken to separate the serum.The titers of the murine and rabbit polyclonal antibodies were detected by ELISA,and the reactivity was measured by Western blot,indirect immunofluorescence assay(IFA) and immunoprecipitation(IP).Results The plasmid pET-28a-M was constructed correctly as identified by sequencing.The titers of murine and rabbit polyclonal antibodies were 1:100 and 1:256 000respectively,and the polyclonal antibodies had reactivity with different RV strains.Conclusion The murine and rabbit polyclonal antibodies against M protein were successfully prepared,which provides important biological tools for exploring the interaction between M protein and host protein as well as studying the pathogenesis of RV.
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@#Objective To express and purify the protein of variable region of adeno-associated virus 9(AAV9) capsid in prokaryotic cells,and prepare rabbit polyclonal antibody against it.Methods DNA sequence encoding variable region of AAV9 capsid protein was designed,synthesized and inserted into prokaryotic expression vector pET-30a. The obtained plasmid pET-30a-AAV-VR was transformed to E.coli BL21(DE3),induced by IPTG to express the multivalent antigenic peptide and purified by Ni-NTA resin under denaturation conditions. Male Japanese large-eared white rabbits were immunized with the AAV9 variable region protein after dialysis and renaturation to prepare polyclonal antibody,which was determined for the antibody potency by indirect ELISA,and for the specificity by Western blot and cellular immunofluorescence.Results The recombinant prokaryotic expression plasmid pET-30a-AAV-VR expressing the variable region of AAV9 capsid was constructed correctly as identified by XhoⅠ and BglⅡ digestion. The expressed protein was recognized by His tag antibody after purification with a relative molecular mass of about 20 000. The potency of rabbit polyclonal antibody was 1∶10 240 000,which specifically recognize AAV9 capsid protein.Conclusion The capsid variable region protein of AAV9 was successfully expressed and rabbit polyclonal antibody with high potency was prepared,which laid a foundation of the subsequent development of AAV vector and the research of AAV biological function.
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@#Objective To express the globular head domain HA1 gene of influenza virus(IV)in prokaryotic cells,optimize the induced expression conditions,and purify the protein in order to obtain IV HA1 protein with good immunogenicity.Methods Influenza A virus[A/Saratov/CRIE-250/2017(H3N2)],Influenza A virus[A/Hebei/F076/2018(mixed)]and Influenza A virus[A/USA/LAN＿(P5)＿HA/2018(H1N1)]were truncated,and amino acid sequence of63-286 globular head domain was obtained. The genes were optimized and synthesized according to the codon commonly used in E.coli,and named 17Sa,Hebei and USA. The 17Sa point mutation gene was named as 17Sa change. The four genes were cloned into prokaryotic expression vector pET-28a(+)to construct recombinant plasmids respectively,which were transformed into E.coli BL21(DE3)competent cells and induced by IPTG. The protein expression conditions were optimized,and the protein was purified by His labeled nickel ion protein purification column.Results The 762 bp target gene was successfully inserted,and the recombinant plasmid was confirmed to be constructed correctly by double enzyme digestion(NheⅠ/XhoⅠ). The expressed recombinant proteins USA with a relative molecular mass of about 26 000,17Sa,p17Sa and Hebei with a relative molecular mass of about 28 000,showed specific binding to mouse anti-His antibody. The recombinant proteins were all expressed in the form of inclusion bodies,and the expression was highest after induction at 37 ℃ for 8 h. The purified recombinant proteins 17Sa,17Sa change,Hebei and USA had a purity of 90%,85%,95% and 80%,respectively.Conclusion The target protein was successfully expressed and purified by prokaryotic expression system with good reactivity,which lays a foundation of the detection of influenza antibody and the development of new vaccines.
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@#Objective To express the capsid proteins VP1 and VP3 of hepatitis A virus(HAV) in prokaryotic cells and evaluate their immunogenicity.Methods VP1 and VP3 gene fragments were amplified by PCR,cloned into vector pETG28a to construct recombinant expression plasmids pET-G28a-VP1 and pET-G28a-VP3,which were transformed into competent E.coli BL21(DE3),induced by IPTG,and then analyzed by 12% SDS-PAGE.The target protein was purified by ion exchange chromatography,renatured and combined with several adjuvants to immunize mice.The mice were divided into VP1-MF59,VP1-AH,VP1-AP,VP1-AP-10CpG,VP1-AP-50CpG,VP3-AP,VP3-VP1-AP and PBS control groups,five for each group.Serum IgG antibody titers of mice in various groups were detected by ELISA,and serum neutralizing antibody titers of mice in VP1-AP,VP3-VP1-AP and PBS control groups were detected by rapid fluorescence focus immunosuppression experiment.Results Colony PCR and sequencing showed that the recombinant plasmids pET-G28a-VP1 and pET-G28a-VP3were constructed correctly.The recombinant proteins VP1 and VP3,with relative molecular masses of about 37 000 and26 000 respectively,mainly existed in the form of inclusion bodies,the expression levels were 18.6% and 32.4%,and the purity was 86.3% and 84.7%,respectively.The recombinant proteins VP1 and VP3 reacted specifically with rabbit anti-HAV antiserum and mouse anti-HAV-VP3 antiserum respectively.The serum IgG antibody titer of mice in VP1-AP-50CpG group was significantly higher than that in VP1-AP group(q=22.05,P <0.01),and the serum IgG antibody titer of mice in VP3-VP1-AP group was significantly higher than that in VP1-AP group and VP3-AP group(q=22.05 and 22.49 respectively,each P <0.01).Compared with PBS control group,the serum neutralizing antibody titer of mice in VP1-AP and VP3-VP1-AP group increased significantly(q=7.79 and 25.11 respectively,P<0.01) Conclusion Prokaryotic HAV capsid proteins VP1 and VP3 showed high purity and good immunogenicity,and the addition of CpG in the preparation was beneficial to enhance the immunogenicity of antigens.This study laid a foundation of the development of HAV recombinant subunit vaccine.
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@#Objective To express CamA(Clostridiodies difficile adenine methltransferase A,CamA)protein with methylase activity in prokaryotic expression system.Methods The gene sequence of CamA protein of the standard strain of C.difficile1870 was amplified by PCR,cloned into plasmid pGEX-4T-1-MBP,transformed into E.coli HB101 and induced by 1 mmol/L IPTG to express the recombinant target protein. After purification with Amylose Resin,CamA protein was digested by tobacco etch virus(TEV)protease,and verified for its methylase activity using MTase-Glo~(TM)Methyltransferase Assay in vitro.Results PCR sequencing showed that the cloned CamA gene sequence was correct,in which no base mutation occurred. The recombinant expression plasmid pGEX-4T-1-MBP-CamA was digested by EcoRⅠand BamHⅠ,which showed that 1 731 bp of CamA gene was connected to the vector plasmid. The relative molecular mass of the recombinant protein was about 108 800(with 1 MBP tag),and the purity was over 90% after purified with Amylose Resin. Under the condition of20 μmol/L DNA and 20 μmol/L SAM at room temperature for 30 min,0. 5 μg CamA produced SAH at a concentration of about 101. 60 nmol/L and the enzyme activity was(0. 339 ± 0. 027)U/mg.Conclusion The CamA protein of C.difficile has been successfully expressed and purified with methylase activity,which lays a foundation of further study on the function of CamA and its role in the occurrence,development and treatment of C.difficile infection.
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@#Objective To express insulin-degrading enzyme(IDE)mutant T142A in prokaryotic cells and detect its activity.Methods According to the results of multi-sequence alignment and IDE substrate co-crystal structure,an active residue in β6-strand structure of IDE were predicted.The recombinant plasmid ppSUMO-T142A,with the site mutation of threonine 142 to alanine,was constructed by point mutation technique and expressed by E.coli prokaryotic expression system.After purification by nickel ion column affinity chromatography,ion exchange chromatography and gel filtration chromatography,the mutant T142A was obtained and determined for the activity by fluorescence method.Results IDE amino acid sequence is highly conserved among 16 species.T142 directly participates in substrate binding,interacts with substrate cleavage sites,and is close to important structures such as catalytic active sites and door-subdomains.The mutation of recombinant plasmid ppSUMO-T142A was proved to be correct by sequencing.The expressed fusion protein His-SUMO-T142A was mainly existed in soluble form in the supernatant at a concentration of 18 mg/mL,with a relative molecular mass of about 131 000;After three steps of purification,the purity of mutant T142A reached 86%.The maximum reaction rate(V_(max))of T142A catalytic degradation of fluorescent substrate V was 501.06 min~(-1) and the Michaelis constant(K_m) was 9.01μmol/L.Compared with wild-type IDE(V_(max) was 2 814.32 min~(-1),K_m was 11.93μmol/L),the activity of T142A decreased significantly.Conclusion The activity of IDE mutant T142A expressed in this study greatly decreases,while T142 is an important residue for IDE to play its enzymatic function,which provides an experimental basis for the development of new IDE activity regulatory molecules.
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@#Objective To optimize the condition for prokaryotic expression of recombinant tetanus toxin heavy chain fragment C(rTTHc) protein.Methods The rTTHc gene fragment after optimization of codon was inserted into prokaryotic expression vector pET30a,low temperature expression vector pCold Ⅱ and high temperature expression vector pBV220separately.The constructed recombinant plasmids were transformed to E.coli BL21(DE3).The expression levels and solubility of recombinant protein at various temperatures were compared.Results The expression level of pBV220-rTTHc after induction at 42 ℃ for 4 h was relatively low,and the protein solubility was poor.The expression level of pET30a-rTTHc after induction at 37 ℃ for 4 h was equivalent to that of pCold-rTTHc after induction at 15 ℃ for 8 h,while the solubility of the former was slightly lower than that of the latter.However,both the expression level and solubility of pET30a-rTTHc after induction at 28 ℃ for 4 h were high,while the expression time was short.Conclusion The pET30a-rTTHc induced by2 mg/mL IPTG at 28℃ is optimal for high expression of rTTHc protein.
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@#Objective To express dengue virus(DENV)NS2B-NS3 protease in E.coli,optimize the expression conditions and determine the enzyme activity,so as to lay a foundation of screening and discovering of lead compounds targeting DENV.Methods Codon-optimized NS2B-NS3 gene was inserted into pET-28a vector to construct recombinant prokaryotic expression plasmid pET-28a-NS2B-NS3,which was transformed E.coli Rosetta(DE3)competent cells and induced by IPTG to express NS2B-NS3 protease. The optimal expression conditions of NS2B-NS3 protease in E.coli were determined by optimizing induction length,induction temperature and IPTG concentration. NS2B-NS3 protease was isolated and purified by HisTrap~(TM) affinity chromatography column and measured for the protease activity by fluorescence resonance energy transfer(FRET)assay.Results The recombinant prokaryotic expression plasmid pET-28a-NS2B-NS3 was constructed correctly as identified by restriction analysis(NheⅠ/XhoⅠ)and sequencing. The optimal expression conditions of NS2BNS3 protease in E.coli were as follows:induction temperature of 20 ℃,induction length of 10 h and IPTG concentration of0. 2 mmol/L. The purified NS2B-NS3 protease showed a purity of more than 90% with a exhibited a of 20 mg/L,which bound to mouse monoclonal antibody against His-tag specifically and had good hydrolytic activity with a specific activity of 16. 111 U/mg,a K_m of 16. 46 μmol/L and a k_(cat) of 0. 028/s.Conclusion DENV NS2B-NS3 protease with high purity and activity was successfully prepared,which laid an experimental foundation of the establishment of high-throughput screening model for inhibitors targeting NS2B-NS3 protease.
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Anthocyanidin reductase (ANR) is one of the key enzyme in the flavonoid biosynthetic pathway, and its catalytic activity is important for the synthesis of plant anthocyanin. In this study, specific primers were designed according to the transcriptome data of Lonicera japonica Thunb., and the CDS, gDNA and promoter sequences of ANR genes from Lonicera japonica Thunb. and Lonicera japonica Thunb. var. chinensis (Wats.) Bak. were cloned. The results showed that the CDS sequences of LjANR and rLjANR were 1 002 bp, the gDNA sequences were 2 017 and 2 026 bp respectively, and the promoter sequences were 1 170 and 1 164 bp respectively. LjANR and rLjANR both contain 6 exons and 5 introns, which have the same length of exons and large differences in introns. The promoter sequences both contain a large number of light response, hormone response and abiotic stress response elements. Bioinformatics analysis showed that both LjANR and rLjANR encoded 333 amino acids and were predicted to be stable hydrophobic proteins without transmembrane segments and signal peptides. The secondary structures of LjANR and rLjANR were predicted to be mainly consisted of α-helix and random coil. Sequence alignment and phylogenetic analysis showed that LjANR and rLjANR had high homology with Actinidia chinensis var. chinensis, Camellia sinensis and Camellia oleifera, and were closely related to them. The expression levels of LjANR and rLjANR were the highest in flower buds and the lowest in roots. The expression patterns at different flowering stages were similar, with higher expression levels in S1 and S2 stages and then gradually decreased until reaching the lowest level in S4 stage, after a slow increase in S5 stage, the expression levels decreased again. The expression levels of ANR genes in the two varieties showed significant differences in roots, S2 and S5 stages, while the differences in stems, flower buds, S1, S3 and S6 stages were extremely significant. The prokaryotic expression vector pET-32a-LjANR was constructed for protein expression. The target protein was successfully expressed of about 59 kD. This study lays a foundation for further study on the function of ANR gene and provides theoretical guidance for breeding new varieties of Lonicera japonica Thunb.
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@#Objective To express and purify Cc PT1 protein from Aspongopus chinensis in prokaryotic cell.Methods Thesynthesized Cc PT1 gene was cloned to vector p GEX-4T-1 to construct recombinant expression plasmid p GEX-4T1-Cc PT1,which was then transformed to competent E.coli Rosetta strain and induced by IPTG.The induction temperature(20 ℃ and37 ℃),final concentration of IPTG(0.25,0.5,0.75 and 1 mmol/L)and induction time(6,8,10,12 h)were opti-mized.The obtained protein was purified by GST protein purification system,which was then analyzed by 10% SDS-PAGEand identified by Western blot.GST tags were removed by Pre Scission Protease during purification.Results The recombi-nant protein GST-Cc PT1 was expressed in the form of inclusion body with a concentration of 0.026 9 mg/ml,of which therelative molecular mass was 29 800,consistent with the expectation.The optimum induction condition was induction withIPTG of final concentration of 0.75 mol/L for 12 h at 20 ℃.The purified protein was more than 90% in purity and boundspecifically to mouse monoclonal antibody against GST.After remove of GST tags,Cc PT1 protein showed a relative molecu-lar mass of about 2 830 and the yield was 11.15%.Conclusion A.chinensis Cc PT1 protein was expressed by prokaryoticexpression system,and the purity of Cc PT1 protein was high after purification,which laid a foundation of the in-depth studyof anticancer peptides of A.chinensis.
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1-Deoxy-D-xylulose-5-phosphate synthase (DXS), the first key enzyme in 2-methyl-D-erythritol-4-phosphate (MEP) pathway, catalyzes the condensation of glyceraldehyde-3-phosphate with pyruvate to 1-deoxy-xylose-5-phosphate (DXP). In this study, PgDXS1, PgDXS2, and PgDXS3 genes were cloned from the root of Platycodon grandiflorum (P. grandiflorum). The open reading frame (ORF) of PgDXS1, PgDXS2, and PgDXS3 were 2 160, 2 208, and 2 151 bp in full length, encoding 719, 735, and 716 amino acids, respectively. Homologous alignment results showed a high identity of PgDXSs with DXS in Hevea brasiliensis, Datura stramonium and Stevia rebaudiana. The recombinant expression plasmids of pET-28a-PgDXSs were constructed and transformed into Escherichia coli (E. coli) BL21 (DE3) cells, and the induced proteins were successfully expressed. Subcellular localization results showed that PgDXS1 and PgDXS2 were mainly located in chloroplasts, and PgDXS3 was located in chloroplasts, nucleus and cytoplasm. The expression of three DXS genes in different tissues of two producing areas of P. grandiflorum were assayed via real-time fluorescence quantitative PCR, and the results showed that all of them were highly expressed in leaves of P. grandiflorum from Taihe. Under methyl jasmonate (MeJA) treatment, the expression levels of three PgDXS genes showed a trend of first decreasing and then increasing at different time points (3 - 48 h), and the activity of DXS showed a trend of first increasing and then decreasing in three tissues of P. grandiflorum. This study provides a reference for further elucidating the biological function of PgDXS in terpenoid synthesis pathway in P. grandiflorum.
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@#Abstract： Objective To clone PE_PGRS35 gene of Mycobacterium tuberculosis（MTB），construct recombinant vector pET28a⁃PE_PGRS35，express and purify the PE_PGRS35 protein of MTB H37Rv heterologously，and explore a new target against MTB after bioinformatics analysis. Methods The PE_PGRS35 coding gene was amplified by PCR and used to construct the expression vector pET28a⁃PE_PGRS35 by recombinant cloning technology，which was transformed to E. coli BL21（DE3）after successful sequencing and induced by using IPTG. The obtained PE_PGRS35 protein was purified by Ni column affinity chromatography and analyzed by bioinformatics. Results The pET28a⁃PE_PGRS35 prokaryotic expression vector was constructed correctly as identified by sequencing. The PE_PGRS35 protein was mainly expressed in the form of inclusion bodies，with a relative molecular mass of about 53 000 and a purity of 90%. Bioinformatics analysis showed that PE_PGRS35 protein was an acid⁃labile protein，with main secondary structure of β⁃sheet and random coil，and no transme⁃ mbrane region，which was presumed to be an extramembrane protein with 39 phosphorylation sites and two conserved domains. Total 10 proteins，including Rv1769，PPE8，PPE64，PPE54，PPE24，PPE16，PPE35，PPE6，PPE28 and PE2， interacted with PE_PGRS35 protein. Conclusion PE_PGRS35 protein with high purity was successfully obtained，which provided a reference for the further development of new targets for drugs against MTB.
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Deacetylation of chitin is closely related to insect development and metamorphosis. Chitin deacetylase (CDA) is a key enzyme in the process. However, to date, the CDAs of Bombyx mori (BmCDAs), which is a model Lepidopteran insect, were not well studied. In order to better understand the role of BmCDAs in the metamorphosis and development of silkworm, the BmCDA2 which is highly expressed in epidermis was selected to study by bioinformatics methods, protein expression purification and immunofluorescence localization. The results showed that the two mRNA splicing forms of BmCDA2, namely BmCDA2a and BmCDA2b, were highly expressed in the larval and pupal epidermis, respectively. Both genes had chitin deacetylase catalytic domain, chitin binding domain and low density lipoprotein receptor domain. Western blot showed that the BmCDA2 protein was mainly expressed in the epidermis. Moreover, fluorescence immunolocalization showed that BmCDA2 protein gradually increased and accumulated with the formation of larval new epidermis, suggesting that BmCDA2 may be involved in the formation or assembly of larval new epidermis. The results increased our understandings to the biological functions of BmCDAs, and may facilitate the CDA study of other insects.
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Animals , Bombyx/metabolism , Metamorphosis, Biological/genetics , Larva/metabolism , Gene Expression , Insect Proteins/metabolism , Chitinالملخص
c-Myc protein encoded by c-Myc (cellular-myelocytomatosis viral oncogene) gene regulates the related gene expression through the Wnt/β-catenin signaling pathway, and has received extensive attention in recent years. The purpose of this study was to express Helicoverpa armigera c-Myc gene (Ha-c-Myc) by using prokaryotic expression system, prepare the polyclonal antibody, examine the spatio-temporal expression profile of Ha-c-Myc, and investigate the possible function of Ha-c-Myc in regulating H. armigera sterol carrier protein-2 (SCP-2) gene expression. The Ha-c-Myc gene was amplified by PCR and cloned into a prokaryotic expression plasmid pET-32a(+). The recombinant plasmid pET-32a-Ha-c-Myc was transformed into Escherichia coli BL21. IPTG was used to induce the expression of the recombinant protein. Protein was purified by Ni2+-NTA column and used to immunize New Zealand rabbits for preparing the polyclonal antibody. The Ha-c-Myc expression levels in different developmental stages (egg, larva, prepupa, pupa, and adult) of H. armigera and different tissues (midgut, fat body, head, and epidermis) of the prepupa were determined by real-time quantitative reverse transcription PCR (qRT-PCR). Ha-c-Myc siRNA was synthesized and transfected into H. armigera Ha cells. The relative mRNA levels of Ha-c-Myc and HaSCP-2 in Ha cells were detected by qRT-PCR. Results showed that the pET-32a-Ha-c-Myc recombinant plasmid was constructed. The soluble Ha-c-Myc protein of about 65 kDa was expressed in E. coli. The polyclonal antibody was prepared. Western blotting analysis suggested that the antibody had high specificity. Enzyme linked immunosorbent assay (ELISA) showed that the titer of the antibody was high. Ha-c-Myc gene expressed at all developmental stages, with high levels in the early and late instars of larva, and the prepupal stage. Tissue expression profiles revealed that Ha-c-Myc expressed in various tissues of prepupa, with high expression level in the midgut, but low levels in the epidermis and fat body. RNAi results showed that the knockdown of Ha-c-Myc expression significantly affected transcription of HaSCP-2, leading to a 50% reduction in HaSCP-2 mRNA expression level. In conclusion, the Ha-c-Myc was expressed through a prokaryotic expression system, and the polyclonal anti-Ha-c-Myc antibody was obtained. Ha-c-Myc may promote the expression of HaSCP-2 and play an important role in the lipid metabolism of H. armigera. These results may facilitate further study on the potential role and function mechanism of Ha-c-Myc in H. armigera and provide experimental data for exploring new targets of green pesticides.
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Animals , Rabbits , Escherichia coli/metabolism , Enzyme-Linked Immunosorbent Assay , Moths/genetics , Blotting, Western , Larva/genetics , Isoantibodies/metabolism , Antibody Specificityالملخص
Objective:To construct a recombinant plasmid pET30a-leucine-rich repeat (LRR) containing 15 (LRRC15) of Taenia solium, prokaryotically express and purify the LRRC15 recombinant protein, and prepare a rabbit polyclonal antibody. Methods:The LRRC15 protein encoding gene of Taenia solium was obtained by whole gene synthesis; it was cloned into pET30a vector, and the recombinant plasmid pET30a-LRRC15 was constructed and identified by double-enzyme PCR; the recombinant plasmid was transformed into competent cells of Escherichia coli BL21 (DE3), and the recombinant protein LRRC15 was induced to express by isopropyl-beta-D-thiogalactopyranoside (IPTG), the expression product was analyzed and identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE); the LRRC15 recombinant protein was purified by Ni-IDA affinity columns, the purified recombinant protein was analyzed and identified by SDS-PAGE, and the specificity of the purified recombinant protein was identified by Western blot (WB); the New Zealand rabbits were immunized with purified LRRC15 recombinant protein to prepare polyclonal antibodies against LRRC15, and the potency of the purified polyclonal antibody was determined by indirect enzyme-linked immunosorbent assay (ELISA). Results:After PCR identification, a band with a length of 1 506 bp was amplified, which was consistent with the LRRC15 gene; after SDS-PAGE and WB identification, the LRRC15 target protein with a relative molecular mass ( Mr) of about 55.36 × 10 3 was obtained; after immunizing New Zealand rabbits with purified LRRC15 recombinant protein, a polyclonal antibody against LRRC15 was obtained, and its potency was 1∶1 587 200. Conclusion:The recombinant plasmid pET30a-LRRC15 is successfully constructed, the LRRC15 recombinant protein of Taenia solium is prepared, and a high purity and high potency rabbit anti polyclonal antibody against LRRC15 recombinant protein is obtained.
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We established an indirect ELISA method using Trichinella spiralis trehalase(TsTRE)protein expressed in prokaryotic cells.The TsTRE gene was amplified by RT-PCR and ligated into the pCold I plasmid,which was expressed in E.coli BL21 competent cells.The rTsTRE protein was purified through affinity column chromatography.The TsTRE protein was localized with immunofluorescence techniques,and the immunogenicity of rTsTRE was detected by westernblotting.Subse-quently,rTsTRE protein was used as a coating antigen to establish an indirect ELISA.We optimized the antigen-coating con-centration,serum dilution concentration,antigen-coating incubation time,type of blocking solution,blocking incubation time,HRP-labeled goat anti-rabbit IgG serum dilution concentration,HRP-labeled goat anti-rabbit IgG serum incubation time and response time of TMB.Subsequently,the critical value,repeatability,sensitivity,specificity and clinical detection rate of the ELISA were evaluated.Immunofluorescence indicated that trehalase was abundant in the rod-shaped body,tail and epidermis of Trichinella spiralis muscle larvae.Western-blot indicated that rTsTRE protein combined with the positive serum of mice infected with T.spiralis for 42 d;the band was approximately 60 kDa.The established indirect ELISA had a positive threshold of 0.384;the intra-run and inter-run coefficients of variation were 5.504％-7.630％ and 4.664％-9.929％,and did not exceed 10％.The lowest detectable titer was 1:1 280.No cross reaction was observed with antibodies to Clonorchissinensis,Schistosoma ja-ponicum,Ascaris suum,Toxocara gondii and Toxocara canis,and the clinical negative detection rate was 0％.Thus,we suc-cessfully expressed the rTsTRE protein.Moreover,the established indirect ELISA method using the TsTRE protein as the coating antigen had good repeatability,sensitivity,specificity and clinical detectability,and can be applied to the detection of clinical samples.
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Objective@#To construct the full-length prokaryotic expression plasmid of the wild type of androgen receptor (AR) and the truncated body of four functional domains，and to identify the fusion protein by Western blot and electrophoretic mobility shift assay ( EMSA) ．@*Methods@#Based on the pGEX-4T-1 vector ，the recombinant plasmids were constructed to express the full-length and functional domains of AR. IPTG was used to induce the expression of the recombinant proteins，which were isolated and purified by glutathione sepharose 4B beads under the optimized condition．The specific protein expression in the bacterial lysate and the purified protein isolated with glutathione sepharose 4B beads was identified by Western blot with AR antibody and GST labeled antibody．The purified protein was incubated with a fluorescent probe of the virus，and the complex was detected by electrophoresis in a non-denaturing gel. @*Results @# The prokaryotic recombinant plasmids of full length and three functional domain truncated AR were successfully constructed．The recombinant clones were identified by using bacterial culture as a template，and further verified by double enzyme digestion．It showed that there were identical bands in the same sizes as the inserted fragments．The nucleotide and the amino acid sequences were aligned to the reference sequence in NCBI GenBank．The GST fusion protein，GST-AR-NTD + DBD (96 ku) and GST-AR-NTD (86 ku) were successfully induced and verified． The purified protein could be directly combined with the viral genome DNA．@*Conclusion@#The prokaryotic expression conditions of truncated AR plasmid from the same gene sequence are different．The purified AR protein can be used to understand the direct interaction mechanism between functional domains of AR and other molecules.
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Bacillus cereus belongs to Gram-positive bacteria, which is widely distributed in nature and shows certain pathogenicity. Different B. cereus strains carry different subsets of virulence factors, which directly determine the difference in their pathogenicity. It is therefore important to study the distribution of virulence factors and the biological activity of specific toxins for precise prevention and control of B. cereus infection. In this study, the hemolysin BL triayl was expressed, purified, and characterized. The results showed that the bovine pathogenic B. cereus hemolysin BL could be expressed and purified in the prokaryotic expression system, and the bovine pathogenic B. cereus hemolysin BL showed hemolysis, cytotoxicity, good immunogenicity and certain immune protection in mice. In this study, the recombinant expression of hemolysin BL triayl was achieved, and the biological activity of hemolysin BL of bovine pathogenic ceroid spore was investigated. This study may facilitate further investigating the pathogenic mechanism of B. cereus hemolysin BL and developing a detection method for bovine pathogenic B. cereus disease.
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Cattle , Animals , Mice , Bacterial Proteins/metabolism , Bacillus cereus/metabolism , Hemolysin Proteins/metabolism , Virulence Factors/metabolism , Enterotoxins/metabolismالملخص
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.
الموضوعات
Humans , Carica/genetics , Recombinant Proteins , Carbohydrate Metabolism , Cloning, Molecular , Chinaالملخص
Flavanone 3-hydroxylase (F3H) is a key enzyme in the synthesis of phycocyanidins. In this experiment, the petals of red Rhododendron hybridum Hort. at different developmental stages were used as experimental materials. The R. hybridum flavanone 3-hydroxylase (RhF3H) gene was cloned using reverse transcription PCR (RT-PCR) and rapid-amplification of cDNA ends (RACE) techniques, and bioinformatics analyses were performed. Petal RhF3H gene expression at different developmental stages were analyzed by using quantitative real-time polymerase chain reaction (qRT-PCR). A pET-28a-RhF3H prokaryotic expression vector was constructed for the preparation and purification of RhF3H protein. A pCAMBIA1302-RhF3H overexpression vector was constructed for genetic transformation in Arabidopsis thaliana by Agrobacterium-mediated method. The results showed that the R. hybridum Hort. RhF3H gene is 1 245 bp long, with an open reading frame of 1 092 bp, encoding 363 amino acids. It contains a Fe2+ binding motif and a 2-ketoglutarate binding motif of the dioxygenase superfamily. Phylogenetic analysis showed that the R. hybridum RhF3H protein is most closely related to the Vaccinium corymbosum F3H protein. qRT-PCR analysis showed that the expression level of the red R. hybridum RhF3H gene tended to increase and then decrease in the petals at different developmental stages, with the highest expression at middle opening stage. The results of the prokaryotic expression showed that the size of the induced protein of the constructed prokaryotic expression vector pET-28a-RhF3H was about 40 kDa, which was similar to the theoretical value. Transgenic RhF3H Arabidopsis thaliana plants were successfully obtained, and PCR identification and β-glucuronidase (GUS) staining demonstrated that the RhF3H gene was integrated into the genome of A. thaliana plants. qRT-PCR, total flavonoid and anthocyanin contentanalysis showed that RhF3H was significantly higher expressed in the transgenic A. thaliana relative to that of the wild type, and its total flavonoid and anthocyanin content were significantly increased. This study provides a theoretical basis for investigating the function of RhF3H gene, as well as for studying the molecular mechanism of flower color in R. simsiib Planch.