Abstract:As one of the key factors for tissue engineering, scaffolds affect the spread and proliferation of seeded cells and the formation of new tissue. Although conventional methods can produce porous scaffolds with different porosities, they are lack controls the porous structures of the scaffolds. In recent years, rapid prototyping (RP) techniques have been developed and have successfully applied to fabricate TE scaffolds. RP techniques can provide accurate control over internal pore architectures and complex-shapes. As a result of these techniques, ideal tissue-engineered constructs could be prepared. This paper reviewed the advantages, potential and future directions of RP techniques in the design and fabrication of TE scaffolds.

Abstract:Hv-S/TPK gene, a resistance related gene to powdery mildew, was cloned by using genechip, and its expression was upregulated after the inoculation of Blumeria graminis to Haynaldia villosa. Using the specific primers of Hv-S/TPK to screen a genomic TAC (Transformation-competent artificial chromosome) library of translocation line 6VS/6AL, a positive TAC was screened. A 5-kb fragment containing Hv-S/TPK was subcloned and identified. This 5160-bp fragment (GenBank Accession No. EU153366) was determined by specific primer walking. The analysis of Hv-S/TPK genomic sequence showed three introns and four extrons between start code and stop code. In the promoter region of Hv-S/TPK, there were W-box and OCS-like elements which were the elements related to disease resistance. In this study, the positive TAC clone was used to as probe in situ hybridized to mitotic metaphase chromosomes of translocation line. The result of fluorescence in situ hybridization (FISH) indicated that the TAC clone containing Hv-S/TPK was from Haynaldia villosa chromosome.

Abstract:The most difficult field in gene therapy is that vector system should offer both a means of successful transfection and a maximum of safety for the patient. Viral vectors and plasmid vectors are traditional vectors; they may cause unwanted immunological side effects resulting from the expression of nontherapeutic genes. Our aim is to develop a new general gene therapy vector which is suggested to be called as Micro-Linear Vector. The gene expression cassette is capped by our designed cap, including promoter, enhancer, objective gene, and RNA-stabilizing sequence, so it can defend the exnuclease in the eukaryotic cell, at the same time, DNA not encoding the objective gene is reduced to a minimum. The GFP gene is separated from the pEGFP-N3 plasmid, and acts as a reporter gene to construct the Micro-Linear Vector, then both the new vector and the plasmid are transfected to cells, the results are tested by fluorescence microscope and flow cytometry. The results show that the Micro-Linear Vector has a high effective of transfection and safety in 293, 3T3, CNE2 and B95-8 cell lines, at the same time it is less toxicity than the plasmid. We can get the rudiments of conclusion that Micro-Linear Vector has high effection of the transfection and more safety than tradition plasmid in eukaryotic cell.

Abstract:We constructed a recombinant strain BL21 (DE3) (pETST3LTBab) including ST1-LTB-a-b fusion gene via molecular technology. The SDS-PAGE and Western blotting indicated that the ST1-LTB-a-b fusion protein was highly expressed in Escherichia coli and the molecular weight of the fusion protein was about 110 kD. The recombinant strain was induced in different concentrations of lactose and different aeration rate. The optimal culture conditions in 20 L fermentor were 1% inoculation (V/V), initial aeration 5 L/min, 0.03 mol/L lactose addition 3 hours after inoculation, and increased the aeration to 12.5 L/min for the following 6 hours. The fusion protein was about 38.53% of total cellular protein. It was nontoxic, immunogenic and protective against enterotoxigenic E. coli and Clostridium perfringens infection The constructed recombinant strain BL21 (DE3) (pETST3LTBab) could serve as a candidate vaccine strain against diarrhea of piglet.

Abstract:Microarray analysis revealed that the expression of ferric reductase (FRP1) can be regulated by the Rim101 protein. In order to find new transcriptional regulatory element in the promoter of FRP1, we analyzed the 1000 bp sequence upstream of ATG to find 2 potential Rim101p binding sites. We generated site-specific mutations in each of the two sites and fused these mutated promoters to LacZ. Then the promoter-LacZ fusion construct was recombinant into wild type and rim101-/- strains for b- galactosidase assay. The results revealed that the FRP1 was up-regulated in alkaline pH and this was caused by iron starvation. The ?650 site, not the ?160 site, had an important role in FRP1 Rim101p-dependent expression. We conclude that Rim101p may interact with the ?650 binding site of the promoter to regulate the FRP1 expression.

Abstract:Swine is an ideal model for diabetes studies. Insulin and insulin resistance are closely related with diabetes. To investigate the effect of SOCS-3 in insulin resistance, porcine primary adipocyte was treated with insulin (100 nmol/L) and dexamethasone (300 nmol/L) to induce insulin resistance. The simi-quantitative PCR results suggested that insulin increased GLUT4, PPARγ and SOCS-3 gene expression in primary culture porcine adipocytes and no change of OB gene expression. Under insulin resistance conditions, SOCS-3 and OB gene expression were up-regulated, whereas GLUT4 and PPARγ gene expression were down-regulated in primary porcine adipocytes. The overexpression of PPARγ gene resulted in the increase of GLUT4 expression by insulin. Different expression levels of SOCS-3 determined the inhibitory effects of insulin signaling. Induction of insulin resistance by dexamethasone was not only due to inhibition of glucose transportation, but also repression of insulin signaling. SOCS-3 might be a potential gene to block the insulin resistance.

Abstract:GPR43 (G protein-coupled receptor 43) is a recently discovered short-chain free fatty acid receptor which plays important role in adipogenesis. Here we explored the transcriptional expression rule of GPR43 in porcine adipose tissue and primary cultured adipocytes. Partial cDNA of GPR43 was successfully cloned from swine by RT-PCR and the expression profile of GPR43 mRNA was studied from different types, different growing stages, and different sites of porcine adipose tissue as well as porcine primary cultured adipocytes. The results showed that porcine GPR43 shared high homology with human (89%), mouse (84%) and rat (83%). The expression level of GPR43 mRNA was significantly higher in adipose tissue of obese pigs than that of lean pigs, and also the expression level gradually increased with age. Further, the abundance of GPR43 mRNA level was higher in subcutaneous fat than in visceral fat. In addition, during the adipocytes differentiation, the expression of GPR43 mRNA increased in a time-dependent manner. These data indicated that GPR43 gene expression was relate to the site of adipose tissue, economic type, and age of pig as well as differentiating state of adipocytes, implying that GPR43 can be a potential factor to regulate adipogenesis.

Abstract:We constructed the plasmid containing the integrated open reading frame (ORF) HPV11 genome, and identified its function, to lay foundation for production of transgenic animal models of HPV11. Recombinant plasmid pQE-Trisystem- EGFP/HPV11 (pE/H) and pQE-Trisystem-EGFP/1.1 copy HPV11 (pE/1.1H) were constructed. Then, the human keratinocyte (KC) was transfected by pE/1.1H, pE/H and closed circular HPV11 and detected. The recombinant plasmid was successfully constructed. The expression of HPV11E6 gene was detected in the experimental group. Fluorescence was observed in the pE/1.1H and pE/H group. The HPV11, pE/H, and pE/1.1 enhanced the KC proliferation, with remarkable differences (P<0.01) from the control group. Amongst the three experimental groups, pE/1.1H was found to be the weakest. The plasmid containing the integrated ORF of HPV11 (1.1 copy HPV11) genome was successfully constructed. The pE/1.1H had the same phenotype of wild-type HPV11 genome. It provided experimental material and methodological guidance for studying the low-risk HPV, as well as for the production of HPV11 transgenic mice.

Abstract:To investigate the immunologic characteristics and cytotoxicity of the RetroNectin-activated cytokine-induced killer cells (CIK) against drug-resistant lung cancer cell lines DDP-A549 (DDP: Cisplatin). Peripheral blood mononuclear cells (PBMC) were collected from healthy donors and divided into two groups: group I and group II. Seeded samples of group I into culture flask precoated with RetroNectin and CD3MAb to induce the CIK cells while seeded the group II into culture flask precoated with CD3MAb. In both groups, IFN-γ was put into the flask on the same day and then IL-2 on the second day. The proliferation of CIK cells was tested by cytometirc analysis. The cytotoxicity activity of CIK cells was determined by MTT assays. The phenotype changes of CIK cells were identified by flow cytometric analysis. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to view the cytotoxicity against DDP-A549 of CIK cells and the changes of DDP-A549. The total CIK cells significantly increased by 524.77 fold in cell proliferation number due to the activation to CIK cells of RetroNectin. The expression rate of CD3+CD56+ cells was (31.40±1.91)%. The cytotoxicity of CIK cells showed statistically significance between DDP-A549 and the sensitive strains of parental generation A549 (P<0.01). There was no significant difference of CIK cells’ cytotoxicity between two groups when the effector: target ratio was fixed (P>0.05). RetroNectin can significantly improve the proliferation activity of CIK cells. There was no evident influence to the cytotoxicity of CIK cells. CIK cells may be used as the immuotherapy to lung adenocarcinoma owing to its significant inhibition to the proliferation of DDP-A549.

Abstract:To study the possibility of using hydroxypropyl chitosan-based blend membranes as carriers of corneal cells in tissue engineering, we prepared three kinds of blend membranes labeled hydroxypropyl chitosan/chondroitin sulfate, hydroxypropyl chitosan/gelatin/chondroitin sulfate and hydroxypropyl chitosan/oxidized hyaluronic acid/chondroitin sulfate. The transparency, water content and ability of protein adsorption of the blend membranes were measured. To evaluate the cytocompatibility of the blend membranes with corneal epithelial cells, rabbit corneal epithelial cells were cultured on the surface of the carrier membranes. The morphological characteristics, cell adhesion, cell proliferation and the activity of lactate dehydrogenase (LDH) in the media were investigated. Three kinds of blend membranes had good optical transmittance, suitable water content and ability of protein adsorption. The results showed that the less injury was made to corneal epithelial cells by the hydroxypropyl chitosan/gelatin/chondroitin sulfate blend membrane than the others. This kind of membrane was favor of the growth and adhesion of corneal epithelial cells. The hydroxypropyl chitosan/gelatin/chondroitin sulfate blend membrane is a promising carrier of corneal cells and can be used in reconstruction of tissue engineered cornea.

Abstract:White spot syndrome virus (WSSV) is one of the most important pathogens in shrimp farm throughout the world. Many researches on WSSV have been done, but no efficient approach has been gained to protect and cure the disease. In this study, we constructed a single-chain fragment variable (scFv) antibody library displayed on phage using spleen cells from mice immunized with denatured WSSV. After several rounds of panning respectively against purified intact WSSV virions and purified VP28 expressed in Escherichia coli, five novel scFv antibodies specifically against WSSV were selected, one of which, clone P75E8, recognized a linear epitope. The location in virions of the epitopes recognized by the five scFv clones was determined by immunoelectron microscopy. This study provides a new way to obtain more different antibodies specifically binding to WSSV, and especially provides a new strategy to obtain scFvs against linear epitopes.

Abstract:The knowledge of the relationship between sequence characteristics of insecticidal crystal proteins (ICP) and their inhibitory against Plutella xylostella provided helpful information for the rational design of ICP with desirable activity against Plutella xylostella.The four key loops of ICP with determined activities against Plutella xylostella were selected to study the quantitative relationship between sequence characteristics and insecticidal activity. The first principle components’ score vectors for 20 amino acids were assigned to converting amino acids into data. The six key sites X3, X9, X12, X13, X14 and X19 were predicted by stepwise regression method. The amino acids L/ X3, S/ X9, S/ X12, T/ X13, A/ X14 and G/ X19 found by partial least squares regression and second order polynomial models were predicted to increase the activity of ICP against Plutella xylostella.

Abstract:To demonstrate the fructose metabolism pathway in Bifidobacterium Longum NCC2705 and to construct its fermentation model, we explored the comparative proteome cultivating the strain on glucose or fructose, based on a proteomic reference map of B. longum NCC2705 constructed earlier. Then, we used matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry and electro-spray ionization tandem mass spectrometry (ESI-MS/MS) for differently expressed proteins identification. Furthermore, with semi-quantitative RT-PCR we determined the distinctively expressed proteins at the level of transcription. Proteomic comparison of glucose- and fructose-grown cells demonstrated much similarity. On the page of fructose there were all the enzymes and proteins that exist during the process of glucose degradation. We observed a greater variation of more than three-fold for the identified 9 spots representing 5 protein entries by MALDI-TOF MS. The sugar-binding protein specific to fructose (BL0033) and an ABC transporter ATP binding protein (BL0034) showed higher expression level from cells grown on fructose. It was also determined by semi-quantitative RT-PCR subsequently. BL0033 time course and concentration experiments showed that the induction time correlated to higher fructose concentration, and increased expression of BL0033. Fructose was catabolized via the same degradation pathway as glucose at the level of proteomics. BL0033 was induced by fructose. All results suggest that the uptake of fructose into the cell may be conducted by a specific ABC transport system, in which BL0033 and BL0034 as components might have played an important role.

Abstract:The gene of b-glucuronidase from Thermotoga maritima was cloned into the plasmid pHsh, and expressed in Escherichia coli JM109. The recombinant protein was purified to homogeneity by a simple step, heat treatment. The recombinant enzyme had a molecular mass of 65.9 kD. The optimal activity of b-glucuronidase was found at pH 5.0 and 80oC. The purified enzyme was stable over a pH range from 5.8 to 8.2 and had a half life of 2 h at 80oC. The kinetic experiments at 80oC with p-nitrophenyl-b- glucuronide as substrate gave a Km and Vmax of 0.18 mmol/L and 312 u per mg of protein. The purified enzyme could transform glycyrrhizin to glycyrrhetinic acid.

Abstract:The performance of a novel anaerobic bioreactor, spiral automatic circulation (SPAC) reactor, was investigated in lab-scale. The results showed that the average COD removal efficiency was 93.6% (91.1%~95.7%), with influent concentration increased from 8000 mg/L to 20 000 mg/L, at 30oC and hydraulic retention time (HRT) of 12 h. The removal efficiency remained at 96.0%~78.7% when HRT was shortened from 5.95 h to 1.57 h, as the influent concentration was kept constantly at 20 000 mg/L. The highest organic loading rate (OLR), volumetric COD removal rate and volumetric biogas production of the SPAC reactor were 306 gCOD/(L·d), 240 g/(L·d) and 131 L/(L·d), respectively. When increasing influent COD concentration (from 8000 mg/L to 20 000 mg/L), the effluent COD concentration maintained at low level (852?mg/L for average) with volumetric COD removal rate increased by 162% and volumetric biogas production increased by 119%. With reduced HRT (from 5.95 h to 1.57 h), the volumetric COD removal rate and volumetric biogas production were increased by 191% and 195%, respectively. The SPAC reactor shows good performances in adapting the continuous change of influent COD and HRT.

Abstract:The ECM25 deletion mutant of industrial brewing yeast, G03/a, was constructed by replacing the ECM25 gene with the kanMX gene. The transformant was verified to be genetically stable. The PCR analysis showed that ECM25 gene in the G-03/a was deleted. Under aerobic conditions of 11oC and 28oC, compared with the host strain G-03, the excretive glutathione concentration of G-03/a increased by 21.4% and 14.7%, respectively. Strains G-03 and G-03/a were inoculated in flasks and cultivated continuously for 4 generations. Compared with the host strain G-03, the glutathione concentration in the main fermentation broth and final beer of strain G-03/a increased by 32.1% and 13.8%, the stability index (SI) increased by 7.7% and 5.3%, respectively, and the flavor resistance staling value (RSV value) in final beer increased by 45.0%. During EBC fermentation, the glutathione concentration in the main fermentation broth of strain G-03/a increased by 34.0%, compared with the host strain G-03. Furthermore, no significant difference in routine fermentation parameters was found. The strain G-03/a is proved to be an excellent anti-staling brewing yeast to improve beer flavor stability.

Abstract:Atomic force microscope (AFM) was used to study biotoxicity of food preservative sodium benzoate (SB) at the single cellular level. Lymphocyte morphology and membrane ultrastructure treated with SB at different concentrations and time were analyzed visually. As compared to the normal lymphocyte, the cell morphology and membrane was significantly changed and its ultrastructure was also complicated. After treated with SB, the Rp-v, Rq, Ra and values were changed. The statistical analysis of lymphocytes after treated with SB was studied, and discussed its mechanism.

Abstract:Taxol is the most effective antitumor agent developed in the past three decades. It has been used for effective treatment of a variety of cancers. A taxol-producing endophytic fungus Pestalotiopsis pauciseta (strain CHP-11) was isolated from the leaves of Cardiospermum helicacabum and screened for taxol production. The fungus was identified based on the morphology of the fungal culture and the characteristics of the spores and screened for taxol production. The amount of taxol produced by this endophytic fungus was quantified by HPLC and it produced 113.3 mg/L, thus the fungus can serve as a potential material for fungus engineering to improve taxol production. This fungal taxol also had strong anticancer activity against some cancer cells viz., BT 220, H116, Int 407, HL 251 and HLK 210 tested by Apoptotic assay and it is indicated that with the increase of taxol concentration from 0.005–0.05 mmol/L, taxol induced increased cell death through apoptosis.

Abstract:Types of cofactor independency for newly found oxidoreductases sequences are usually determined by experimental analysis. These experimental methods are both time-consuming and costly. With the explosion of oxidoreductases sequences entering into the databanks, it is highly desirable to explore the feasibility of selectively classifying newly found oxidoreductases into their respective cofactor independency classes by means of an automated method. In this study, we proposed a modified Chou’s pseudo-amino acid composition method to extract features from sequences and the k-nearest neighbor was used as the classifier, and the results were very encouraging. When l=48, w=0.1, the areas under the ROC curve of k-nearest neighbor in 10-fold cross-validation was 0.9536; and the success rate was 92.0%, which was 3.5% higher than that of pseudo-amino acid composition. It was also better than all the other 7 feature extraction methods. Our results showed that predicting the cofactors of oxidoreductases was feasible and the modified pseudo-amino acid composition method may be a useful method for extracting features from protein sequences.

Abstract:The cp36 gene encoding an adhesive protein was amplified by PCR from genomic DNA of rabbit P. multocida C51-3 strain, and cloned into the pMD18-T vector and then sequenced. The mature adhesive protein without a signal peptide of cpm36 gene was amplified by PCR from the recombinant plasmid pMD18-cp36, then cloned into the prokaryotic expression vector pQE30 to provide a recombinant plasmid pQE30-cpm36. The recombinant protein of CPM36 was produced in Escherichia coli M15 harboring the recombinant plasmid pQE30-cpm36 by IPTG induction, and the recombinant protein purified by the affinity chromatography with Ni2+-NTA resin. The sequence analyses showed that the ORF of cp36 gene was 1032 bp in length, and DNA homology of the cp36 genes between the C51-3 strain and the previously reported different serotype strains of P. multocida in GenBank was 76.9 to 100%. The SDS-PAGE analyses revealed a single fusion protein band with a molecular weight of 37 kD, and the Western blotting analysis demonstrated that the recombinant protein CPM36 and native 36 kD protein of C51-3 were recognized specifically by an antiserum against the recombinant protein, suggesting that the recombinant protein is an antigenic protein.

Abstract:Fermentation kinetics is important for optimizing control and up-scaling fermentation process. We studied submerged fermentation kinetics of Morchella. Applying the genetic Algorithm in the Matlab software platform, we compared suitability of the Monod and Logistic models, both are commonly used in process of fungal growth, to describe Morchella growth kinetics. Meanwhile, we evaluated parameters involved in the models for Morchella growth, EPS production and substrate consumption. The results indicated that Logistic model fit better with the experimental data. The average error of this model was 5.8%. This kinetics model can be useful for optimizing and up-scaling fungal fermentation process.

Abstract:The regulation of a target gene expression is very important in gene therapy. However, constitutive or inappropriate expression of the genes with traditional expression system may interfere with the effect of the gene therapy, even may lead to lethal side effect. We constructed an RU486 inducible eukaryotic vector carrying DsRed protein and evaluated its regulatable effect in vitro. The single vector named PDC-RURED was constructed with molecular biological methods, which contained DsRed gene, promoter and mifepristone-inducible system. To minimize any potential interference, we spaced the two transcriptional elements with a 1.6 kb insulator. The vector was identified by different enzyme restrictions, sequencing analysis and PCR assay. We demonstrated the regulatable expression of this vector after transfection in HEK293 cells by fluorescence microscopy and flow cytometry. In the absence of RU486, no significant DsRed protein activation was observed, whereas in the presence of RU486 up to 40 fold activation of the DsRed protein was observed in cultured cells. The data show that the novel eukaryotic expression plasmid vector can be used to regulate the expression level of genes of interest in appropriate time under the control of RU486. This inducible expression vector provides a powerful tool for the research of gene regulation and gene therapy.

Abstract:The open reading frame of Spinacia oleracea Betaine Aldehyde Dehydrogenase (SoBADH) was retrieved from Spinacia oleracea and inserted into the Agrobacterium tumefaciens binary vector pBin438, which was driven by CaMV35S promoter, and produced the new binary vector pBSB. A. tumefaciens LBA4404 carrying this plasmid was used in genetic transformation of plants. Forty-five primary transgenic plants were detected by PCR and verified by the Southern blotting from 65 regenerated plants, of which 27 transgenic plants had only one copy of T-DNA. The Northern blotting and Western blotting analysis indicated that the SoBADH gene had been transcribed mRNA and expression protein in the transgenic cotton lines. The testing of SoBADH activity of transgenic plant leaves showed that the enzyme activity was much higher than that of the non-transgenic cotton. The growth of transgenic plants was well under the salinity and freezing stress, whereas the non-transgenic plant grew poorly and even died. Challenging with salinity, the height and fresh weight of transgenic plants was higher compared with those of non-transgenic plants. Under the freezing stress, the relative conductivity of leaf electrolyte leakage of the transgenic cotton lines was lower than that of non-transgenic plants. These results demonstrated that the SoBADH gene could over express in the exogenous plants, and could be used in genetic engineering for cotton stress resistance.

Abstract:To construct the recombinant vector pBV220-scFv and express anti-clenbuterol (CBL) scFv antibody in Escherichia coli, we amplified the scFv gene using plasmid pCANTAB5E-CBL as a template, recombined it with pPICZαA, then amplified the scFv-His-tag gene from plasmid pPICZαA-scFv and linked it with expression plasmid pBV220. We identified the recombinant plasmid by restrictive enzyme digestion, PCR amplification and sequence analysis. Finally, we transformed the recombinant vector into E. coli DH5a that was temperature-induced and expressed recombinant protein. We identified the recombinant protein by SDS-PAGE, Western blotting and indirect competitive ELISA .The results show that recombinant plasmid pBV220-scFv contained the inserted fragment with highest homology about 99.8%. The expression of scFv induced by temperature show 37 kD Mw and anti-His-tag mAb recognized-activity by SDS-PAGE and Western blotting respectively, and could competitively combine with CBL, the IC50 is 4.55 ng/mL. The recombinant plasmid pBV220-scFv is constructed and expresses the scFv gene of CBL in E. coli successfully. This study suggests the corresponding immunoassay methods could be set up by the recombinant scFv.

Abstract:A wheat stripe rust resistance gene was screened out from Aegilops tauschii which is relative genera of wheat species, broadening the genetic basis of the anti-disease character of wheat species. By hybridizing diversed Ae. Tauschii species, which is either resistant or susceptible to wheat stripe rust, a dominant wheat stripe rust resistance gene was detected from Ae. Tauschii (Coss.) Schmal Y206. The novel gene was temporarily designated as YrY206. By bulk segregation analysis, four microsatellite markers Wmc11a, Xgwm71c, Xgwm161 and Xgwm183 were found to be linked to YrY206 with genetic distances of 4.0, 3.3, 1.5 and 9.3 cM, respectively. According to the locations of the linked markers, the resistance gene was located on chromosome 3DS. Based on the chromosomal location and the resistance pattern of the gene, YrY206 should be a novel stripe rust resistance gene.

Abstract:Gene of human adiponectin (ADPN) was cloned by PCR-driven overlap?extension. The ADPN gene was linked into pGEM-T vector. After the sequence was determined, the ADPN gene was subcloned into expression vector pPIC3.5K to yield the recombinant expression vector pPIC3.5K-ADPN. The recombinant plasmid was transformed into Pichia pastoris GS115 by electroporation, then the recombinant strain was identified by PCR and Southern blotting. After induction by methanol, ADPN was expressed in GS115, then the protein was identified by Western blotting. The results showed that the ADPN was expressed successfully. The optimum conditions of expression were 30°C and 1% methanol inducing 48 h.

Abstract:To test the hypothesis that in vitro protein cross-linking could be accomplished in three concerted steps: (1) a change in protein conformation; (2) formation of interchain disulfide bonds; and (3) formation of interchain isopeptide cross-links, we studied Escherichia coli tartrate dehydratase beta subunit (TtdB). With polymerase chain reaction (PCR) technique, wild and Cys/Ser mutant genes were amplified from E. coli BL21 cells and subcloned into expression plasmid pTrcHisC. Recombinant proteins, which were associated with formation of inclusion bodies induced by IPTG, were purified by immobilized metal affinity chromatography (IMAC) and refolded by dialysis. In thermal unfolding and oxidative refolding experiment, wild TtdB was proved to form cross-linked dimmers/oligomers as revealed by SDS-PAGE; cross-linking intensity was obviously weakened when the loading buffer contained the reducing agent dithiothreitol (DTT). The residual cross-linking was isopeptide bonds; no dimmers/oligomers were detected when the refolding and unfolding solution contained DTT. In addition, Cys/Ser point mutation abrogated its ability to cross-link into homodimers, which showed disulfide bonds could facilitate the following formation of isopeptide bonds.

Abstract:To obtain the recombinant 18 kD protein with high purity and normal bioactivity of Cysticercus cellulosae (rCE18), E. coli cells with the rCE18 were disrupted ultra-sonically, and the inclusion bodies were washed with a solution containing 0.2% deoxycholic acid sodium (DOC)and 2% DOC, respectively. Then they were denatured with 0.9% sodium lauroyl sarcosine (SKL)followed by dialysis and gel filtration to refold and purify the target protein. At the same time, this method was compared with GST-FF affinity chromatography and recovering from SDS-PAGE gel. Biological activity of purified rCE18 was analyzed with indirect ELISA, and the purity of the products was identified using SDS-PAGE. The purity of refolded inclusion bodies exceeded 60% and the total recovery of activated protein rCE18 was about 41.3%. The specificity of rCE18 reached up to 97.2% using indirect ELISA. An effective way for purifying and refolding rCE18 expressed in E. coli as inclusion bodies was established. rCE18 with higher purity and activity was obtained, which has the potential for developing diagnosis methods of porcine cysticercosis.

Abstract:We selected 12 antigens corresponding to commonly used autoantibodies in clinical practice to prepare antigen microarray. We chose NBT/BCIP color reaction as the end detection strategy to develop a new autoantibody protein chip detection system. Using this system, we optimized the best spotting solution, spotting concentration of the 12 antigens and the dilution of serum. We prepared a protein chip that could detect 12 autoantibodies simultaneously using the optimized antigen concentration. We established a new method to determine the cutoff of each autoantibodies by evaluation of 678 positive and 120 negative serum of clinical sample. We also evaluated the sensitivity and specificity of our new detection system. The optimal spotting solution was 0.1% TBST, the dilution of serum was 1:4 and the best spotting concentration of the 12 antigens were ANA 520 μg/mL, Ro-60/SSa 465 μg/mL, La/SSb 530 μg/mL, Jo-1 530 μg/mL, Scl-70 525 μg/mL, Sm 520 μg/mL, Ro-52/SSa 615 μg/mL, RF 340 μg/mL, CCP 465 μg/mL, u1RNP 410 μg/mL, CENP-B 490 μg/mL and dsDNA 580 μg/mL respectively. It had higher coincidence rate compared to current clinical used methods. We have developed a 12 antigens protein chip for the detection of autoantibodies based on the NBT/BCIP color reaction system. This system was fast, convenient, efficient, and cost-effective.