N-glycanase is a class of deglycosylation enzymes, widely used in the study of N-glycosylation modification of glycoprotein. In this study, an N-glycanase gene (OsPNGase A, XM_015775832) with high GC content (69.48%) was cloned from rice and then the yeast secretory expression vector pPICZ(α)A-OsPNGase A was constructed for the purpose of transformation to Pichia pastoris. After induction in Pichia pastoris SMD1168H, the target protein was purified by DEAE Sepharose and HisTrap HP chromatography, with a yield of 12.3 mg OsPNGase A from 1 L fermentation medium, showing a specific activity of 258 U/mg. SDS-PAGE revealed that the purified OsPNGase A was a single band and showed consistentcy with the expected molecular weight. OsPNGase A could act on transferrin recombinantly expressed in rice, avidin recombinantly expressed in corn and horseradish peroxidase. Furthermore, OsPNGase A showed higher activity than commercial PNGase F towards avidin. OsPNGase A displayed the highest digestion activity at pH 6.0 and 40 °C, and was also active in the neutral and alkaline environment. Despite the fact that OsPNGase A was inhibited by reducing agents and surfactants, it still maintained partial enzymatic activity in 100 mmol/L β-ME or DTT. Therefore, the successful expression of rice OsPNGase A provides a new tool for the study of plant glycoproteins and the establishment of yeast secretion expression system lays the foundation for the preparation of PNGase A.

Nucleases is an important enzyme widely used in biotechnology. A codon optimized nuclease gene (SNU) from Northern Shrimps was inserted into pPICZα A vector, and expressed extracellularly in strain SMD1168H. On the basis of multi-copy recombinant strain, we further optimized the expression condition and characterized SNU. SNU was highly expressed and stable after 1% methanol induction for 72 h, yield reached 1.4×10⁵ U/mL. SDS-PAGE electrophoresis demonstrated that this is a N-linked glycoprotein of 50 kDa. It was purified by one step DEAE Sephadex chromatography to the purity of about 15 mg/L with a specific activity of 6.291×10⁶ U/mg. Functional analysis on the nuclease activity indicated that it was stimulated by bivalent iron, such as Ca²⁺, Mn²⁺, Co²⁺ and Mg²⁺, but inhibited by Zn²⁺, Cu²⁺ and high salt. Meanwhile, it was irreversibly inactivated at 70 ℃ for 10 min.
Animals ; Codon ; Electrophoresis, Polyacrylamide Gel ; Endonucleases ; biosynthesis ; Glycoproteins ; Hot Temperature ; Penaeidae ; enzymology ; Pichia ; metabolism ; Recombinant Proteins ; biosynthesis

Rutin-degrading enzymes (RDE) can degrade rutin into poorly water soluble compound, quercetin, and cause the bitter taste in tartary buckwheat. In the present study RDE from Yu 6-21 tartary buckwheat seeds was purified by ammonium sulphate precipitation, followed by hydrophobic interaction chromatography on Phenyl Sepharose CL-4B, ion exchange chromatography on CM-Cellulose and gel filtration chromatography on Sephadex G-150. Purified RDE showed single band with molecular weight of 66 kDa on SDS-PAGE. The optimum pH and temperature of RDE were 5.0 and 50 ℃ respectively. The Km was 0.27 mmol/L, and the Vmax was 39.68 U/mg. The RDE activity could be inhibited by Cu²⁺, Zn²⁺, Mn²⁺ and EDTA, and showed tolerance to 50% methanol (V/V). The N terminal sequence (TVSRSSFPDGFLFGL) was obtained by Edman degradation method and 15 internal peptide sequences were determined by MALDI-TOF-MS (matrix-assisted laser desorption ionization time of flight mass spectrometry). These results established the foundations for identification of the candidate gene of RDE via transcriptome data and further studying RDE biological function.

The study is aimed to construct high quality Salvia miltiorrhiza cDNA library and obtain the SmJAZ8 gene of S. miltiorrhiza by yeast two-hybrid system. In this study， full-length cDNA was synthesized from roots， stems， leaves， flowers and hairy roots of S. miltiorrhiza. The full-length cDNA library was synthesized by SMART method and constructed with DSN homogenization technique. The results showed that the library capacity was 1.45×10⁶， the recombination rate was 100%， and the average size of the insert was 500-2 000 bp. The recombinant vector of pDEST-pGADT7-SmJAZ8 was constructed and transformed into Y2HGold strain. The interaction protein was screened by yeast two-hybrid system. The DnaJ protein and UBQ protein were screened by yeast two-hybrid system. This study has successfully constructed a full-length cDNA library of S. miltiorrhiza， and laid the foundation for the follow-up study on functional gene screening and gene function of S. miltiorrhiza.
Co-Repressor Proteins ; genetics ; DNA, Complementary ; Gene Library ; Plant Proteins ; genetics ; Salvia miltiorrhiza ; genetics ; Two-Hybrid System Techniques

Exonuclease Ⅷ (Exo Ⅷ), an ATP-independent dsDNA 5'-3' exonuclease, is a candidate protein with great application value for in vitro DNA recombination. However, the application of Exo Ⅷ in DNA recombination in vitro has not been reported. In this study, the recombinant expression vector of the truncated Exo Ⅷ (tExo Ⅷ) with the full exonuclease activity was built and used to achieve the overexpression of tExo Ⅷ in Escherichia coli. Based on the purified tExo Ⅷ protein with high-purity, the feasibility of tExo Ⅷ applied in vitro DNA recombination and effects of the reaction temperatures, reaction duration, and homology arm lengths were examined. The results showed that tExo Ⅷ was highly expressed in soluble form in E. coli. One liter of bacterial culture yielded 92.40 mg of purified tExo Ⅷ with the specific activity of 1.21×10⁵ U/mg. In a 10 μL recombination system containing 2.5 U tExo Ⅷ, the highest cloning efficiency was achieved in a reaction at 25 °C for 12.5 min and followed by incubation at 50 °C for 50 min. With addition of Pfu DNA polymerase, the homology arm extension strategy can effectively improve the recombination efficiency. Using competent E. coli Mach1 T1 with 2.2×10⁶ cfu/μg transformation efficiency as recipient cell, the recombination of a 1 kb fragment with a 21 bp homology arm and a 5.8 kb linearized vector can form about 1.1×10⁴ recombinant clones per μg vector, and the positive rates was over 80%. The recombination efficiency was increased with the increasing length of homology arm ranged from 8 to 21 bp. Under the optimal reaction condition, only 8 bp homology arm can still achieve valid DNA recombination. This novel in vitro DNA recombination system mediated by tExo Ⅷ was particularly characterized by its easy preparation, no limitation on restriction sites and high recombination cloning efficiency. All results revealed that the new efficient gene cloning system has potential application in the field of molecular biology.
Cloning, Molecular ; Escherichia coli ; genetics ; Exonucleases ; genetics ; Recombinant Proteins ; metabolism ; Recombination, Genetic

The aim of this paper was to investigate the flavonoids of callus of transgenic and non-transgenic Saussurea involucrate and its antitumor activity on the esophageal cancer CaEs-17 cells. The species and content of mono-phenols were detected by high performance liquid chromatography. The growth of human esophageal cancer CaEs-17 cells was detected using CCK-8 assay, apoptosis morphology observation and flow cytometry. Expression of related apoptotic genes Bax and Bcl-2 were determined by qPCR. The results showed that the content of total flavonoids in the transgenic callus was 2.72 times that of the non-transgenic callus. The cyanidin-galactoside was detected in the transgenic callus, but not in the non-transgenic callus. The inhibitory effect of the extracts from the transgenic callus on CaEs-17 cells was more significant than that of the non-transgenic callus, and the IC₅₀ value had a decreased of 26.4%. Flow cytometry analysis results showed that the apoptosis induction effect of the extracts from the transgenic callus on CaEs-17 cells was significantly better than that of the non-transgenic callus. Fluorescence quantitative PCR analysis results showed that the extracts from the transgenic callus could up-regulate the expression of proapoptotic gene Bax and down-regulate the expression of apoptotic gene Bcl-2, and the regulation effect of the transgenic callus was more significant. Therefore, compared with the non-transgenic callus, the antitumor activity of the extracts from the callus of transgenic S. involucrate on the esophageal cancer CaEs-17 cells was significantly increased, which was closely related to the accumulation of cyanidin-galactoside and its metabolism-related flavonoid compounds in the transgenic callus.
Apoptosis ; Chromatography, High Pressure Liquid ; Flavonoids ; Humans ; Phenols ; Plant Extracts ; Saussurea

To research the expression of key enzymes in saikosaponin biosynthesis and the content of saikosaponin under the drought stress, the study focused on the gene-level and the end product responses to environmental change. Taking the five months of Bupleurum chinense as research materials, the contents of saikosaponin A and saikosaponin D under different stress levels were measured by HPLC. The drought was simulated by poly ethylene glycol. The real-time fluorescence quantitative PCR was used to analyze the expression of four key enzymes genes HMGR, IPPI, FPS, β-AS and the expression of β-tubulin was set as a reference gene. The results showed that drought stress significantly improved the content of saikosaponin. The contents of SSa and SSd were highest researching 0.648% and 0.781%, respectively when the concentration of PEG was 10%. Meanwhile, the results reflected that the expression of four key enzymes had risen differently and FPS, β-AS raised significantly(P<0.01). In addition, the results of correlation analysis showed that there was a significant positive correlation between the expression of the four key enzymes genes and the content of saikosaponin. In a word, the contents of secondary metabolites were regulated by the expression of key enzymes genes under the drought stress in B. chinense.

OBJECTIVETo investigate the quality and quantity changes of Flos Lonicerace during flowering stages in Hanzhong GAP base in order for properly harvesting and quality control.

METHODThe yield index of Flos lonicerace in four flowering stages was determined, and the contents of chlorogenic acid and the total flavonoid in the samples were determined by HPLC and the colorimetry, respectively. The volatile oils were extracted by the SFE-CO2 and the constituents were analyzed by GC-MS.

RESULTThe yield in the first two flowering times was attributed to about more than 80% of total yield, and the number of flower buds for each plant in the first time was almost the same as the sum of the other three times. The drying rate of the three-site green flowers kept the highest during the first flowering time, and the drying rate of the two-site white flowers kept the highest during the second flowering time. The contents of chlorogenic acid and the total flavonoid in the first flowering time were higher than those in the second, and among them, the two-site white flowers kept the highest, about 3.5% and 13.2%, respectively. For the sample flowers in in the second flowering time, the three-site green flowers kept the highest level of chlorogenic acid and the total flavonoid, about 2.7% and 11.6%, respectively. From the volatile oil samples in the five periods of Flos lonicerace in the first flowering time, 19 components were identified by GC-MS. They were composed by three types of compounds, n-diolefines, fatty acids and steroids. Nonacosane and hentriacontane had the relatively higher amount with more than 40% and 20%, respectively. The relative contents of vitamine E were higher too, about 8.15% - 10.43%. And, gamma-5-sitostene-3-ol, stigmasta-5,2-diene-3-ol and campesterol were also detected. Among these steroids, the relative contents of the first two were 4.90% - 6.9%, 1.06%- 4.10%, respectively.

CONCLUSIONThe flowering samples in the first two times were attributed to the most to the total yield. The samples of the two-site white flower and the whole-white flower had the higher comprehensive quality. The components of vitamine E and the steroids in the volatile oil need to be paid more attention.

Biomass ; Flowers ; chemistry ; growth & development ; Lonicera ; chemistry ; growth & development ; Oils, Volatile ; analysis ; Seasons

OBJECTIVETo investigate the constituents of Ervatamia hainanensis systematically.

METHODVarious chromatographic techniques were applied to isolate and purify the constituents of this plant. The structures were elucidated by spectroscopic analysis.

RESULTEight compounds were obtained, which were identified as alpha-amyrin acetate (1), 11-oxo-alpha-amyrin acetate (2), beta-sitosterol (3), cycloart-23-ene-3beta, 25-diol(4), cycloart-25-ene-3beta, 24-diol (5), 5alpha, 8alpha-epidioxyergosta-6, 22-dien-3beta-ol (6), ibogamin-3-one (7), beta-daucosterol (8).

CONCLUSIONCompounds 1, 2, 4- 7 were isolated from this plant for the first time.

Apocynaceae ; chemistry ; Ergosterol ; analogs & derivatives ; chemistry ; isolation & purification ; Oleanolic Acid ; analogs & derivatives ; chemistry ; isolation & purification ; Plant Roots ; chemistry ; Plant Stems ; chemistry ; Plants, Medicinal ; chemistry ; Triterpenes ; chemistry ; isolation & purification

To establish human beta-defensin-3 gene transgenic cell lines as competent donor cells for the production of transgenic animals using somatic cell nuclear transfer (SCNT). Firstly, we obtained human beta-defensin-3 by RT-PCR from human placenta, and subsequently inserted the fragment hBD into the corresponding site of the plasmid pBCP. Then we moved the combined fragment BCD (including 5' and 3' regulating region of beta-casein and hBD) into the corresponding site of the plasmid pEGFP-C1. Finally we successfully constructed mammary-specific expression vector pEBCD. We transected pEBCD into Holstein Fetal fibroblast cells by Lipofectamine TM-2000 and selected in medium with G418 for three to four weeks. We identified G418 resistant transfectants by PCR, RT-PCR and EGFP detection. Our results indicated that human beta-defensin-3 gene stably was integrated into the open region of the chromatin in G418 resistant fibroblast cells. Meanwhile we identified the expression of human beta-defensin-3 in the supernatant of stable transfected mammary epithelial cells by Western blotting. This study may provide competent transgenic donor cells for the production of transgenic animals by SCNT and improve the efficiency of transgenic cloning.
Animals ; Animals, Genetically Modified ; Caseins ; genetics ; Cattle ; Epithelial Cells ; metabolism ; Genes, erbB-1 ; genetics ; Genetic Vectors ; genetics ; Humans ; Mammary Glands, Animal ; cytology ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; beta-Defensins ; biosynthesis ; genetics