Simultaneous determination of 13 bioactive components in Jiawei Zuojin Pill by HPLC-MS/MS / 中草药

Objective: To develop and validate an high performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-ESI-MS/MS) method for simultaneously qualitative and quantitative determination of 13 major bioactive components (ferulic acid, costunolide, baicalin, paeoniflorin, tetrahydropalmatine, rutecarpine, berberine, palmatine, evodiamine, naringin, hesperidin, saikosaponin a, and saikosaponin d) in Jiawei Zuojin Pills (JZP). Methods: The chromatographic separation was performed on a Thermo Syncronis C18 column (100 mm × 4.6 mm, 3.0 μm) with a gradient elution of methanol and 0.02 mol/L ammonium acetate in water at a flow rate of 0.35 mL/min, and the injection volume was 10 μL. The 13 major bioactive components were detected using an electrospray ionization source in ESI+ and ESI- ionization mode, quantified by multiple reaction monitor (MRM) scanning at the same time. Results: The linear ranges of ferulic acid, costunolide, baicalin, paeoniflorin, tetrahydropalmatine, rutecarpine, berberine, palmatine, evodiamine, naringin, hesperidin, saikosaponin a and saikosaponin d were 2-80 μg/mL (r = 0.999 2), 0.5-20.0 μg/mL (r = 0.999 1), 3.5-140.0 μg/mL (r = 0.999 8), 1-40 μg/mL (r = 0.999 2), 0.3-12.0 μg/mL (r = 0.999 1), 1-40 μg/mL (r = 0.999 2), 3-120 μg/mL (r = 0.999 7), 2.5-100.0 μg/mL (r = 0.999 5), 0.5-20.0 μg/mL (r = 0.999 3), 0.5-20.0 μg/mL (r = 0.999 1), 1-40 μg/mL (r = 0.999 1), 0.3-12.0 μg/mL (r = 0.999 2), 0.3-12.0 μg/mL (r = 0.999 2), and the average recoveries were 99.5% (RSD = 4.11%), 98.9% (RSD = 4.88%), 100.2% (RSD = 1.08%), 99.2% (RSD = 3.23%), 99.5% (RSD = 4.13%), 99.7% (RSD = 3.23%), 98.6% (RSD = 2.78%), 99.9% (RSD = 3.12%), 101.3% (RSD = 4.53%), 98.7% (RSD = 3.43%), 99.8% (RSD = 3.58%), 97.9% (RSD = 5.22%), and 101.3% (RSD = 5.13%), respectively. The contents of 12 batches of the 13 major bioactive components were 0.324-0.383, 0.051-0.072, 3.225-3.466, 0.154-0.198, 0.015-0.062, 0.144-0.199, 2.145-2.982, 0.441-0.953, 0.032-0.099, 0.062-0.089, 0.111-0.178, 0.012-0.065, 0.011-0.069 mg/g, respectively. Conclusion: The developed method is simple, specific, and sensitive, and it can be applied for the determination of 13 major bioactive components and the quality control of JZP.

Recombinant batroxobin expressed highly in Pichia pastoris / 生物工程学报

Methylotrophic yeast, Pichia pastoris was used to express recombinant batroxobin, and a technology route of producing recombinant protein was finally established. We synthesized batroxobin gene artificially by means of recursive PCR. pPIC9-batroxobin was constructed and transformed into Pichia pastoris GS115 (his4). Recombinant batroxobin was expressed in yeast engineering strain and it was purified from the culture supernatant. 10 mg of recombinant batroxobin was purified from 1 liter fermentation media, it exhibited specific activity of 238 NIH units/mg and had molecular weight of 30.55 kD. The purified recombinant protein converted fibrinogen into fibrin clot in vitro, and shortened bleeding time in vivo. This study laid a foundation of development of hemostatic of recombinant snake venom thrombin-like enzyme.

Expression, purification and characterization of rat procarboxypeptidase B in Pichia pastoris / 生物工程学报

Carboxypeptidase B is a metalloenzyme, which is widely used for commercial and research purposes. Commercially available CPB purified from porcine or bovine pancreas is very expensive, and is not totally free from other proteases. In order to express the rat proCPB in Pichia pastoris, total RNA extracted from SD rat pancreas cells was reversely transcripted to synthesize cDNA, and the proCPB ORF was synthesized by PCR. After digestion with Xho I and EcoR I , the fragment was inserted into pPIC9, and the recombinant plasmid was named as pPIC9-proCPB. By digestion with Sac I , the lined pPIC9-proCPB was transformed into Pichia pastoris strains GS115 with PEG1000 and integrated into their genomes. In the inducement of methanol, recombinant proCPB was successfully expressed in Pichia pastoris, and could be secreted into the supernatant in the culture. After optimizing the fermentation conditions, a higher production could be obtained when GS115-proCPB was induced in BMGY (pH6.0) at 28CC, with addition of 0.5% casein. The yield of recombinant protein reached 500mg/L, achieving over 94% of total protein in the culture supernatant. The purity of recombinant CPB can reach 96% after two step phenyl sepharose F F purification, and 38% of total protein can obtained after optimizing the pufication method. Comparing to the specific activity 180u/mg of CPB purchased from Sigma, the specific activity of recombinant CPB is 110u/mg. Mass spectrometry analyses showed the mass of the recombinant CPB was 35.1 kD, which is very close to the theory value 35.2 kD. Amino acid sequencing of N-terminal of recombinant CPB further indicated proCPB was expressed successfully and modificated correctly after translation.

Proteomic analysis of paclitaxel-induced apoptosis in MCF-7 human breast carcinoma cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of paclitaxel-induced apoptosis in MCF-7 human breast carcinoma cells.</p><p><b>METHODS</b>In this study, the proteins extracted from paclitaxel-induced apoptotic MCF-7 cells were analyzed by 2-dimentional gel electrophoresis (2-DE), and compared with those from untreated MCF-7 cells. The differential proteins were identified by mass spectrometry.</p><p><b>RESULTS</b>At 24 hour after paclitaxel (100 nmol/L) treatment, MCF-7 cells were collected and extracted the whole proteins. Seventeen up-regulated or down-regulated proteins were found by analysis of the differential proteomic 2-DE map. Six of them were identified by mass spectrometry. They were enolase 1, chloride intracellular channel 1, keratin 8, ribosomal protein S12, galectin-1 and histidine triad nucleotide binding protein, respectively.</p><p><b>CONCLUSION</b>We effectively found the changed proteins in the process of paclitaxel-induced apoptosis in MCF-7 human breast carcinoma cells by proteomic techniques. These up-regulated or down-regulated proteins are important molecules for our further research about the mechanism of paclitaxel-induced apoptosis.</p>

Expression of ATR-Fc fusion protein in CHO cells / 生物工程学报

ATR-Fc is a fusion protein consisting of extracellular domain of human anthrax toxin receptor (ATR) and a fragment (hinge, CH2, and CH3 domains) of the Fc of human IgG1. The aim of ATR-Fc expression is to get an antibody-like molecule binding to protective antigen (PA), a component of anthrax toxins, this fusion protein may compete with cell surface receptor for PA binding, and block the transport of lethal factor (LF) and edema factor (EF) into cells, thereby act as an antitoxin to prevent and treat anthrax infection. A DNA fragment encoding N-terminal amino acids 1-227 of ATR and human IgG1 Fc was inserted into the Hind III and Not I sites of pcDNA3.1 to generate the eukaryotic vector pcDNA3.1/ATR-Fc for expression of ATR-Fc fusion protein. Using lipofectine-mediated gene transfer technique, pcDNA3.1/ATR-Fc was transfected into CHO-K1 cells. After selected with G418, a recombinant CHO cell line, ATR-Fc-1D5, whose expression level was about 10 - 15 microg/(10(6) cells x d), was established. The recombinant protein expressed by the ATR-Fc-1D5 cells was purified with protein A chromatography. The experimental results demonstrated a direct and specific interaction between ATR-Fc and PA assessed by ELISA.

Expression of fusion protein of parathyroid hormone and transferrin N-terminal half-molecule in Pichia pastoris / 生物工程学报

The fused gene (PTH-TFN) of parathyroid hormone (PTH) gene and transferring N-terminal half-molecule (TFN) gene was amplified by multiple PCR and inserted into pPIC9 vector. The recombinant plasmid pPIC9-PTH-TFN was transformed into Pichia pastoris GS115 by PEG. After methanol induction, the target protein was expressed in fermentation supernatant at high level. The fused protein PTH-TFN with purity being higher than 95% was finally obtained after purification through two-step chromatography: SP Sepharose Fast Flow and Phenyl Sepharose Fast Flow. Western blot analysis and adenylate cyclase assay proved that the fused protein exhibited the bioactivity to stimulate cAMP synthesis and the ability to bind Fe3+ in the Fe3+ saturation study as the recombinant TFN did indicating that TFN could be used as the transcellar carrier of PTH.

Expression and bioactive characterization of bacteriophage lysin gene of Bacillus anthracis in Escherichia coli / 生物工程学报

The lysin gene of Bacillus anthracis-diagnosing bacteriophage, obtained by PCR amplification,was cloned into the Escherichia coli exepression vector pET22b which has been cleaved by EcoR I and Nde I. The recombinant vector pET22b-gamma lysin was verified to be correctly constructed by PCR, sequencing and enzyme digestion, and highly expressed in E. coli BL21 (DE3), which accounted for about 40 percent of total protein in E. coli BL21 (DE3), while in the 5L fermentor the expression level reached 15g/L. After expression, disruption and purification with three-step chromatography, Streamline SP, SP HP and Sephacryl S-100, the recombinant gamma lysin was finally obtained with purity of higher than 95 percent as determined by gel scan. The final yield following SP HP was 19.1 percent, with a greater-than-350-fold increase in specific activity. The pure enzyme has been shown active to Bacillus anthracis, and not to E. coli, Bacillus subtilis and Bacillus cereus. Its specific activity was about 1400 u/mg.

Development of toxin targeting to VEGF-KDR / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To develop toxin targeting vascular endothelial growth factor receptor II (VEGF-II/KDR) fused with a KDR-binling peptide screened from peptide library.</p><p><b>METHODS</b>By affinity to KDR molecular which expressed specifically by new born vascular endothelial cell, peptides to KDR were screened from C7 peptide library by phage display. Among them, a peptide binding to KDR with high affinity termed as P5 was selected and fused to the N-terminal of Shiga toxin subunit A (StxA). The protein (P5-StxA) was expressed in E. coli.</p><p><b>RESULTS</b>ELISA and Western blot were applied to characterize the binding interaction between the fusion protein, P5-StxA and KDR. Cytotoxicity assay showed that P5-StxA maintained similar toxicity to cell as StxA. In the model of angiogenesis, P5-StxA inhibited selectively VEGF-induced growth of preexisting vessels of the chick chorioallantoic membrane.</p><p><b>CONCLUSION</b>These studies demonstrate the small peptide, P5, maybe be used as carrier of toxin targeting to KDR.</p>

Construction of phage display antibody library to MCF-7 cells and screening of single-chain antibodies against breast cancer cells / 生物工程学报

The aim of this study is to construct a phage display single-chain variable fragment (scFv) library against breast cancer cells and screen the specific antibodies against MCF-7 cells from the library. The BALB/C mice were immunized with MCF-7 cells. Total RNA of spleens was isolated. The heavy-chain (VH) and light-chain variable region genes (VL) of the antibodies were amplified by RT-PCR and joined into a single chain by overlapping PCR with a linker DNA encoding the peptide (Gly4Ser)3. The assembled scFv fragments were cloned into the phagemids(pCANTAB5E) and the recombinant phagemids were used to transform competent E. coli TG1. The transformed TG1 cells were infected by helper phage M13KO7 and the recombinant phagemids were rescued. The scFv fusion proteins were displayed on the surfaces of the recombinant phages. A phage display antibody library of repertoire of 1.2 x 10(6) clones was constructed. The specific antibodies against MCF-7 cells were enriched by 75 times after five rounds of affinity selection. Ten recombinant phages clones that exhibited specific binding to MCF-7 cells were identified. The specificity of those phage clones was analyzed by reactivity against HepG2 cells and Hela cells by ELISA. One of the selected phage clones against MCF-7cells was used to infect E. coli TOP10 to produce the soluble scFv antibodies after induction with IPTG. The strategy of construction and screening of antibody library directed against the whole tumor cells described in this report should be generally applicable to generate tumor cell-specific antibodies.

High expression and characterization of human parathyroid hormone in Escherichia coli / 生物工程学报

Human parathyroid hormone (hPTH) was highly expressed in Escherichia coli by inserted the synthesized whole hPTH cDNA into the vectors pBV220 and pET22b. After expression and disruption, the purified product was acquired through cation exchange chromatography and reverse phase chromatography. From the results of N-terminal sequencing and MALDI-TOF-MS analysis the recombiant prtein was indentified as intact hPTH. In in vitro Bioassays the recombinant hPTH stimulated adenylate cyclase as the standard did. In ovariectomized rats the recombinant hPTH markedly increased the femoral bone mass and bone mineral density.