25 July 2012, Volume 32 Issue 07
    

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  • Fusion Protein Identification as Polymer and Its Analysis of Structure
    NI Bei-bei, FAN Zhen-zhen, CHEN Hong, HUANG Bing-ren
    China Biotechnology. 2012, 32(07): 1-7.
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    Objective: To confirm the polymer structure of the recombinant fusion protein EGF-E4orf4 and its EGFR binding activity. Methods: The gel filtration chromatogram,SDS-PAGE,Western blotting, light scattering, circular dichroism and receptor binding test were used to determine the characters of the protein EGF-E4orf4. Results: It was showed that the fusion protein EGF-E4orf4 formed a polymer. The static light scattering and dynamic light scattering determined that the molecular weight of EGF-E4orf4 is 1.656×107Da and the molecular radius is about 67.90nm, which indicated that EGF-E4orf4 polymerized with 820 monomers. The secondary structure of EGF-E4orf4 was riched in β sheet. Flow cytometry analysis proved that EGF-E4orf4 can combine with the cell surface EGFR. Conclusion: The fusion protein EGF-E4orf4 exists as a polymer and it could bind to EGFR. Therefore, as a potential novel targeted nticancer drug, EGF-E4orf4 has ossibility of clinical application.
  • Effect of GALNT14 on the Migration of Human Breast Cancer Cells MCF-7
    WU Chen, TIAN Huan-na, WANG Yuan-yuan, LIU Fang-ming, ZHANG Xiao-kang, LI Qin-jian, XIE Yuan-yuan
    China Biotechnology. 2012, 32(07): 8-15.
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    The recombinant plasmid—pcDNA 3.1-Flag-T14 was constructed and identified by restriction enzyme digestion and DNA sequencing. pcDNA 3.1-Flag-T14 was transfected into MCF-7 cells with lipofectamine 2000, and positive clones were selected by G418. The expression of GALNT14 in MCF-7 was tested by RT-PCR and Western blot. Wound healing assay and transwell migration assay were performed to detect migration activity. The effect of GALNT14 on the expression of MMP-2,MMP-9,TGF-β1and VEGF was measured by semi-quantitative RT-PCR. The result showed that pcDNA 3.1-Flag-T14 was successfully constructed and GALNT14 was expressed stably in MCF-7 cells. GALNT14 can promote the migration of MCF-7 cells. RT-PCR showed that GALNT14 also increased the expressions of MMP-2,MMP-9,TGF-β1and VEGF mRNA. In conclusion,GALNT14 can significantly improve the migration of MCF-7 cells and it might play an important role in the invasion and metastasis of tumor.
  • Effects of PLGA Degradation on Angiogenesis in vitro
    WU Yan-ge, SUN Xue-feng, YANG Lin, WANG Zheng
    China Biotechnology. 2012, 32(07): 16-19.
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    Objective: To investigate the influences of degradable PLGA scaffold on proliferation, migration and the formation of tube-like structure (TLS formation) of vascular endothelial cells.Methods: PLGA scaffold were immersed in PBS fluid to stimulate the degradation for 1, 2, and 4 weeks. HUVEC (Human Umbilical Vein Endothelial Cells) was cultured with degradation fluid. Cell proliferation, migration and TLS formation were detected by Brdu ELISA, Transwell chamber and tube formation.Results: The PLGA degradation fluid showed no effects on the migration, TLS formation of HUVEC, but the proliferation was increased in 1 week. With the prolonged degradation time, the migration and TLS formation were significantly decreased in 2 weeks, and the proliferation, migration and TLS formation were reduced remarkably in 4 weeks.Conclusions: At the beginning of degradation, PLGA could improve the proliferation function. The concentration of acid products increased with the increase of degradation time, and cell behaviors were retrained, thus inhibiting the angiogenesis of endothelial cells.
  • Propeptide-deleted von Willebrand Factor Improves Heavy Chain Secretion and Bioactivity by Split FVIII Gene Co-transfected Cells
    ZHU Fu-xiang, LIU Ze-long, MIAO Jing, QU Hui-ge, CHI Xiao-yan
    China Biotechnology. 2012, 32(07): 20-25.
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    Dual-vector based FVIII gene split delivery has been developped as an altenative strategy to overcome the packaging limitation of adeno-associated virus (AAV) vectors in hemophilia A gene therapy but the efficacy is undesired for the inefficient secretion of heavy chain. A propeptide-deleted mutant of von Willebrand factor(vWF-ΔPro), which functions as a carrier of FVIII was tested for its effect on dual-vector FVIII gene delivery. 48 hours post-transfection of HEK293 cell with vWF-ΔPro, heavy and light chain genes of a B-domain deleted FVIII (BDD-FVIII), a chain-specific ELISA showed high levels of heavy chain secretion of 142?29ng/ml in the culture supernatant, greater than that of cell without vWF-ΔPro co-transfection(87?15ng/ml). The heavy chain transfected cells showed a very low levels of heavy chain secretion in absence of vWF-ΔPro although improved in presence of vWF-ΔPro, but lower than that of heavy and light chain co-transfected cells indicating a pro-secretion effect of light chain on heavy chain in trans. The light chain showed higher efficient secretion in light chain gene transfection alone or co-transfection with heavy chain, which was not affected by vWF-ΔPro. The Coatest assay showed an obviously higher bioactivity (0.80?0.15IU/ml) in supernatant of vWF-ΔPro, heavy and light chain genes co-transfected cell, compared to vWF-ΔPro-free co-transfection cell (0.41?0.08IU/ml). The supernatant from combined cells separately transfected with heavy and light chain displayed FVIII bioactivity of 0.23?0.09IU/ml in presence of vWF-ΔPro, suggesting a function of vWF-ΔPro in assembly of secreted heavy and light chain into a functional hetero-dimer. The data demonstrated that vWF-ΔPro transfection could improve dual-vector mediated FVIII gene delivery forming a basis for ongoing in vivo study.
  • Effect of Aurora-A Overexpression on Invasion and MMP-9 Expression of Esophageal Carcinoma Cells
    WANG Xiao-xia, LU Na, LIU Zhi-rong, XIE Jun, WANG Hui-zhen, NIU Bo, PEI Yi
    China Biotechnology. 2012, 32(07): 26-30.
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    Objective:To establish Aurora-A overexpressing transfectant clones and investigate its effect on invasiveness as well as protein expression and activity of MMP-9 in esophageal carcinoma cells. Methods:The Aurora-A expressing plasmid was transfected using LipofectamineTM 2000 and the identification of transfected clones was confirmed by Western blot analysis and RT-PCR. The invasive properties of cells were examined by an in vitro Boyden chamber invasion assay. Level of MMP-9 protein expression and activity were measured with Western blot and ELISA as well as gelatin zymography analysis. Results:Aurora-A overexpressing transfectant clone was established, which increased cell invasion as well as protein expression and activity of MMP-9. Conclusion:The elucidation the molecular mechanism for the promotion of invasion in esophageal carcinoma by Aurora-A may lead to the development of new target for effective therapy.
  • The Study of Therapy Efficacy Applied Sheep Amnion Epithelial Cells in Rabbit Radius Defected Models
    ZHU Xue-min, LIU Jun-ping, YANG Yin-feng, WANG Xiu-mei, MI Yan, LI Hai-jun, LI Yan, MENG Qing-gang, CAO Gui-fang
    China Biotechnology. 2012, 32(07): 31-36.
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    To explore the potentials differentiation of sheep amnion epithelial cells into bone in vitro, the sheep amnion epithelial cells of stem cells properties were injected into New Zealand rabbit radius defected models and then observed the radius restoration. The sheep amnion epithelial cells were cultured and made morphological identifications. The rabbit’s left 13-centimetre long radius defected models were artificially divided into high dose group, low dose group and control group randomly. Sheep amnion epithelial cells with the dense of 5×107 and 5×106 in 5ml saline and 5ml saline were injected into high dose group of rabbits, low dose group of rabbits and control group of rabbits respectively. Took the models for X-ray in 2 weeks, 4 weeks and 8 weeks after the sheep amnion epithelial cells transplantations respectively and observed the radius restorations. At the mean time, the radius defected areas were observed by histological methods, and the trabecular bones generating quantities and the bone remodeling time were analysised. Defected radiuses in high dose group of models were restored completely at 8 weeks after the sheep amnion epithelial cells transplantations. Meanwhile, the quality and quantities of trabecular bones in high dose group were better and higher than in the low dose group and it was the same situation between the low dose group and the control group. Thus it can be seen that the sheep amnion epithelial cells can not only be transplanted among various species of animal, but also are effective for defective bone restoration.
  • Toxicity Evaluation of a FAPα-activated Targeting Anticancer Prodrug Z-GP-Dox in Zebrafish
    MA Wei-feng, YANG Fei-hua, ZHAO Hai-shan, DU Jun, CAI Shao-hui
    China Biotechnology. 2012, 32(07): 37-42.
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    Objective: To investigate the toxicity in zebrafish of Z-GP-Dox, a novel FAPα-catalyzed activation targeted anticancer drug designed and synthesized previously. Methods: The mortality of 4-month-old zebrafish and the development of 24hpf (hours post fertilization) embryos were observed after treatment of Z-GP-Dox in different concentrations. The toxic effects of Z-GP-Dox on the zebrafish heart were evaluated with morphological and electrophysiological changes. Doxorubicin was set as a control. Results: The mortality rate of zebrafish in Dox control group showed significant does-dependent manner, while the mortality rate of the structural acylated modification prodrug Z-GP-Dox treated group was much lower. Dox induced malformations of zebrafish embryos and impaired heart function in juvenile. While at the same concentration, there was no significant difference between the Z-GP-Dox treatment group and blank control group in the heart shape and heart rate of the juvenile. When the Z-GP-Dox was hydrolysised by FAPα, its toxicity significantly increased and almost equal to the Dox. Conclusion: When compared with Dox, prodrug Z-GP-Dox toxicity was reduced significantly in zebrafish with characteristics of FAPα enzyme activated targeting release.
  • Transformation and Genetic Analysis of Maize with the Lycb
    HUO Pei, JI Jing, WANG Gang, GUAN Chun-feng, JIN Chao
    China Biotechnology. 2012, 32(07): 43-48.
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    Lycb gene was transformed into embryonic callus derived from Tianta Fifth inbred lines by Agrobacterium-mediated transformation, and the independent T0 transformants and their progenies genetics were analyzed. PCR analysis with 27 T0 transformed plants testified 8 positive plantlets. T1 plantlets were selected by 200 mg/L PPT and seeds of the resistance plants were harvested. T2 transgenic plants were analyzed using PCR, RT-PCR, and the results showed that the six positive lines detected were further confirmed to have PPT resistance. HPLC analysis showed the total beta carotene content from transformed leaves was significantly higher than that of the wild type. The results show that the Lycb gene was able to inherit in the T2 progeny, and transcribed and translated effectively.
  • Induction of Taxus chinensis var. mairei Hairy Roots and Isolation and Purification of Paclitaxel in Hairy Roots
    WANG Ying-fang, HAN Bin, LI Zhong, JIA Zhen, CHEN Yan-fen, HU Xu-guang, YANG Ze-min
    China Biotechnology. 2012, 32(07): 49-52.
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    Objective: To explore Induction system of Taxus chinensis var. mairei hairy roots and isolation and purification of paclitaxel in hairy roots. Methods: Genetic transformation of Taxus chinensis var. mairei by three different Agrobacterium rhizogenes, the effect of some factors on transformation efficiency were analyzed. Paclitaxel in hairy roots was isolated and purified by supercritical CO2 fluid extraction, silica gel column chromatography and high performance liquid chromatography(HPLC). Results: The induction system of Taxus chinensis var. mairei hairy roots was established. The factors influenced transformation efficiency contain Agrobacterium species of Agrobacterium rhizogenes, types of explants, pro-culture, co-culture time and hormone concentrations in the medium. High voltage paper electrophoresis (HVPE) indicated that crown gall were expressed in Taxus chinensis var. mairei hairy roots. Paclitaxel in hairy roots was successfully separated and purified by supercritical CO2 fluid extraction and silica gel column chromatography. The purity of paclitaxel was 98% by HPLC assay. Conclusion: Taxus chinensis var. mairei hairy roots induced by Agrobacterium rhizogenes can produce paclitaxel, as source of paclitaxel.
  • Effect of Interfacial Ligands on the Absorption Behavior of BSA
    MA Hong-mei, ZHANG Gui-feng, LI Chun, KONG Ying-jun, GAO Fei, HU Tao, MA Guang-hui, SU Zhi-guo
    China Biotechnology. 2012, 32(07): 53-59.
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    The effect of interfacial ligands on the adsorption behavior of BSA was investigated using dual polarization interferometry (DPI). The sensor chips of DPI were modified with 3-aminopropyltriethoxysilane (APTES), (3-methylaminopropyl)trimethoxysilane (MAPTMS) and (3-diethylaminopropyl)trimethoxysilane (DAPTMS) respectively. The ligand densities on the modified chips were compared using X-ray photoelectron spectroscopy. The adsorption behaviors of BSA on the three modified chips were characterized using DPI and atomic force microscopy (AFM) respectively. It was found that the adsorbed BSA on the APTES-modified chip occupies a larger area than other ligand-modified ones, suggesting that the higher ligand density led to the more points in binding sites. The ligand density on MAPTMS-modified chip was similar as that on the DAPTMS-modified chip. BSA showed higher BSA adsorption on the DAPTMS-modified chip than the MAPTMS-modified, but the thickness of BSA layers were almost the same, indicating a higher density of BSA adsorbed. AFM images of the BSA adsorbed on the three ligand-modified chips corresponded to the result from DPI detection. The results indicates that the ligand density on the modified chip affects the amount, density and aggregation of BSA on the interfaces.
  • Screening and Classification of a Thermophilic Cellulase-producing Trichoderma sp. Strain and the Study of the Enzyme Properties
    YANG Jie, YE Xiu-yun, YAN Fen, GAO Zhen-na, LI Ren-kuan, LV Wen-jing, LIN Juan
    China Biotechnology. 2012, 32(07): 60-65.
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    A fungal strain, designated as M1, producing thermo-tolerant cellulase was isolated from straw compost and classified as Trichoderma sp. via morphological analysis and its 18S rDNA sequence. The pattern of cellulase synthesis by the strain in submerged fermentation with rice straw as the sole carbon source was investigated as well as the enzyme properties of the carboxymethyl cellulase (CMCase). The maximum CMCase activity was observed at pH 4.4 and the CMCase retained more than 95% activity in the pH range of 4.0~6.0 after incubation at 50℃ for 4h. The optimum temperature for the CMCase activity was 75℃; this CMCase maintained 87% and 65% of the initial activity after incubation for 4h at 50℃ and 60℃, respectively, indicating that the enzyme had good thermostability.
  • Optimization of Single Cell Oil Produced from Cassava Starch by Response Surface Methodology
    AI Zuo-zuo, YAN Ri-ming, YUAN Jin-yun, ZHANG Zhi-bin, ZHU Du
    China Biotechnology. 2012, 32(07): 66-72.
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    Response surface methodology was applied to optimize the Trichosporon fermentans fermentation conditions for microbial lipids produced from hydrolysate of cassava starch. The Plackeet-Burman design was adopted to sort the important factors influencing the lipids yield, and the conditions of lipids production was further optimized by using Box-Behnken design and response surface methodology. The results showed that the temperature, C/N and pH could influence on the lipid yield significantly. The optimized conditions for lipid production were temperature of 28.79℃, C/N of 126.18 and pH of 6.69, and the lipids yield of 14.88g/L which was 28.6% higher than control. Moreover, gas chromatography analysis revealed that the microbial lipid from Trichosporon fermentans mainly included palmitic acid, stearic acid, oleic acid and linoleic acid and it was suggested to be used as an excellent feedstock for biodiesel production.
  • Effects of Intracellular Redox Level on Fermentation Metabolism of Thermoanaerobacter ethanolicus
    SUN Huan-min, GUO Min, IRBIS Cha-gan
    China Biotechnology. 2012, 32(07): 73-78.
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    Coenzyme NADH/NAD+ plays an important role in intracellular oxidation-reduction reactions, and is a necessary cofactor for cell growth and energy metabolism. Regulating the intracellular NADH/NAD+ ratio of microorganisms is an effective means to alter microbial metabolic pathway directionally and obtain the target metabolic products efficiently. Thermoanaerobacter ethanolicus is a representative thermophilic anaerobic and ethanologenic bacteria. This study altered intracellular NADH/NAD+ ratio using carbon sources at different redox status. Then its effect on cell growth and distribution of metabolic products was studied. When glucose and mannitol at different ratios were used as the substrate for fermentation, variations occurred with respect to intracellular redox level, growth characteristics of cells and metabolic products. When glucose was used as the only carbon source, T. ethanolicus grew well, and the ethanol production was 0.79g/L. However, both of the intracellular NADH/NAD+ ratio and ethanol/acetic acid ratio were low, being 0.474 and 4.82 respectively. As the ratio of glucose in the mixed carbon source decreased, the NADH/NAD+ ratio increased, and the ethanol/acetic acid ratio in the fermentation products also showed an increasing trend. When mannitol was used as the only carbon source, the ethanol concentration in the fermentation products was 0.389g/L, and the NADH/NAD+ ratio and ethanol/acetic acid ratio were 1.04 and 16.0 respectively.
  • Degradation of Raw Corn Starch by an α-Amylase (AmyP) from Marine Environment
    PENG Hui, LEI Yin, LIU Yuan-tao, WANG Ying
    China Biotechnology. 2012, 32(07): 79-83.
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    The α-amylase (AmyP) from a marine metagenomic library belongs to the recently classified glycoside hydrolase subfamily GH13_37. AmyP is raw starch degrading enzyme, exhibiting a remarkable ability to digest raw corn starch. The specific activity of raw corn starch was reached (39.6 ± 1.4)U/mg under the optimum pH 7.5 and temperature 40℃. The hydrolysis curve showed that AmyP could hydrolyze raw corn starch at a very high speed. The final hydrolysis degrees were obtained in 30min for 1% raw corn starch and 3h for 4% and 8% concentration. The enzyme’s activity was greatly increased in the presence of DTT. 1% DTT led to a twofold-enhanced activity. The results of scanning electron microscopy and thin-layer chromatography show that AmyP attacks sites on raw corn starch granules with a mode of endo-corrosion, and releases glucose, maltose and maltotriose as end products.
  • Construction of a Fluorescence Detection Method for HCV NS3/4A Protease Activity
    YAN Xing, SHI Ming-lei, CHEN Na, WANG Yang, ZHANG Yan, WANG Zheng, LI Xiao-chen, ZHAO Zhi-hu
    China Biotechnology. 2012, 32(07): 84-88.
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    Objective: To develop a visualized cell method for detecing the existence of HCV NS3/4A protease. Methods: Based on the character that the insertion of NS5AB sequence into certain site of EGFP molecule will keep its fluorescence, constructed EGFP-5AB recombinant molecule. When the NS3/4A was coexpressed in the same cell, the EGFP will be digested into two parts and lost its fluorescence. So the model can be used to detect HCV NS3/4A protease. Three insertion sites were compared to find the best site for insertion; three host cells were transfected to find the best for fluorescence detection. Results: After optimization, the EGFP 173~174 aa is chosen as the best site for NS5AB insertion, CHO-K1 cell is chosen as the best host cell. The digested EGFP1-173 fragment can be detected in the cell without fluorescence, which proved that the method can detect HCV NS3/4A existence sensitively. Conclusion: A fluorescence detection method for HCV NS3/4A protease activity is successfully constructed.
  • Study on Peste Des Petits Ruminants Virus Nucleic Acid Detection Based on Gold-nanoparticle Conjuncted Probe
    TAO Chun-ai, QIU Wen-ying, LI Gang, TIAN Kang-le
    China Biotechnology. 2012, 32(07): 89-94.
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    In order to investigate a rapid method of detecting peste des petits ruminants virus(PPRV) with gold-nanoparticle conjuncted probe,two sets of specific oligonucleotide probes complementary to the ends of the highly conserved region of the PPRV nucleoprotein gene were designed. One was biotin-modified,the other was thioled and conjuncted to gold nanoparticles.During the course of hybridization, the two labeled probes binded to the target nucleic acid respectively, forming a "sandwich"type complex, which was amplified by silver staining after incubated to streptavidin coated immuno-Microwells. Concentration of the target nucleic acid was determined by visual light microscope and spectrophotometry observation. The established method took around 1.5 h and the detection limit for nucleic acid was 10 fmol/L. It would provide theoretical and technical support for the clinical detection of PPRV since it is easy to operate and highly sensitive.
  • Selection of scFv Genes of Foot-and-Mouth Disease Virus Using Ribosome Display
    DAI Peng, ZHOU Guang-qing, LIN Mi, FENG Xia, MA Jun-wu, ZHANG Xiao-xia
    China Biotechnology. 2012, 32(07): 95-101.
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    Objective: To screen the specific single-chain variable Fragment (scFv) gene of Foot-and-Mouth Disease by Ribosome display. Methods: Based on the construction of ribosome display library, five rounds of in vitro transcription, in vitro translation, affinity selection and RT-PCR constructed by ribosome display technology, then sequencing and analysis. Results: ScFv genes of FMDV were screened, and were enriched. Conclusion: Targeted by antigen of FMDV and purified 146S virus particle, FMDV scFv genes were obtained by using ribosome display technology. Not only previous basis for basic research, immunology research, prevention, treatment and diagnostic of FMD, but also for the development of rapid diagnostic techniques of FMD by using single-chain variable fragment were provided.
  • Immobilized Technology Impact on Fermentation ATP Ability of Yeast
    YAN Xiang-ru, LIN Li-ping, HE Ming-fang, CHEN Wei-ping
    China Biotechnology. 2012, 32(07): 102-106.
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    Immobilization method of yeast cell and its application in fermentation production of ATP are discussed. Considering the performance index of immobilized particles(particle size, elasticity and mechanical strength) and the capacity of fermentation producing ATP, orthogonal experiments optimize embedding conditions of the yeast. The optimal immobilization conditions of yeast cell was determined that is 3.5% of polyvinyl alcohol, 2% of sodium alginate, 3% of CaCl2 and 6 hours of cross-linking time. Under this fermentation condition, the content of ATP was the highest, reaching 0.783g/L. Further fermentation experiments confirmed that the immobilization of yeast cell can improve the temperature adaptation range, and lengthen the fermentation cycle of producing ATP.
  • Study on Thermal Stability and Catalytic Specificity of Monoamine Oxidase in Oat Seedlings
    ZHANG Yong-ming, CUI Zhi-feng, HIRASAWA Ei-ji, WU Hai-xia, LI Guo-long
    China Biotechnology. 2012, 32(07): 107-112.
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    FAD-containing monoamine oxidase (MAO; EC 1.4.3.4) oxidises monoamines to their corresponding aldehydes, H2O2, and NH3 in organism. There are seldom reports about MAOs in plants. MAO activity was detected in oat seedlings during germination using benzylamine as substrate. The activities of oat seedlings growing in dark were higher than in light conditions. The activity, reached a peak after germinated for 3 days, was 2.5pKat/mg. and there are little difference about MAO activity in three parts of seedlings, shoots > roots > grains. The results of thermal stability shown oat MAO was unstable in room temperature after purified to homogenate successfully. 50% and 75% of oat MAO activity were lost after the 90-min incubation. Oat MAO shows high substrate specificities for benzylamine and phenethylamine, which are traditional MAO B specific substrates and are oxidised to benzaldehyde and phenylacetaldehde, but not for tyramine, serotonin, histamine or dopamine. The Km values for benzylamine and phenethylamine were 265μM and 705μM, respectively. Catalytic efficiency of oat MAO was lower than human MAO B and Aspergillus niger MAO.
  • The Types of siRNA Off-target Effects and the Strategies for Mitigation
    TANG De-ping, MAO Ai-hong, LIAO Shi-qi, XUE Lin-gui, ZHANG Bing-lin
    China Biotechnology. 2012, 32(07): 113-119.
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    Small interfering RNAs (siRNAs) can specific silence target genes,and are widely used to elucidate gene function,indentify drug targets and develop more specific therapeutics than are currently available. Off-target effects (OTEs) can complicate the interpretation of phenotypic effects in gene-silencing experiments and can potentially lead to unwanted toxicities. siRNAs OTEs include microRNA-like off-target effects, immune stimulation and saturation of the RNAi machinery. The types of off-target effects of siRNAs and methods to mitigate them was focused, to help enable effective application of RNAi technology.
  • Advances of The Protection of Telomeres 1
    CHENG Ling-li, ZHU Da-zhu, HUANG Di-nan, HOU Gan
    China Biotechnology. 2012, 32(07): 120-126.
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    POT1 (protection of telomere 1) was found in unicellular organisms by Baumann in 2001, which have been identified and expressed highly conserved in a wide range of eukaryotes.It plays pivotal roles in protection of chromosome end and regulation of telomere length with other telomeric binding proteins. With the advances of POT1, the mechanisms have being gradually completed due to the new founds in the DNA binding feature of POT1 and chromosome end protection. Furthermore, the ways in which POT1 regulates telomere length has been found being more complex; and how POT1 allows the cell immortalization and promotes tumor progression and induces cell apoptosis have been more clear.As reference recent journals, the article summarizes the functions of POT1 proteins and discusses the interaction with other related proteins.
  • Advance of Large-scale Animal Cell Culture Technology
    MEI Jian-guo, ZHUANG Jin-qiu, WANG Jin-liang, WANG Yu-mao, DING Zhuang, SHEN Zhi-qiang
    China Biotechnology. 2012, 32(07): 127-132.
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    In recent years, large-scale animal cell culture technology in the field of biotechnology as one of the most talked about hot spots, have been widely used in the process of the biomedical research and production. Large-scale animal cell culture technology platform based on bio-reactor technology is being built up gradually and becoming increasingly mature, which will become the powerful tools promoting bio-pharmaceutical industry rapid development. Focusing on the application level of this technology and its recent progress,the differences among the different cell culture technology are analyzed for finding its future direction.
  • Key Enzymes in Soybean Isoflavones Biosynthesis and Its Metabolic Engineering
    CHEN Xuan-qin, ZHANG Le, XU Hui-ni, CHEN Li-mei, LI Kun-zhi
    China Biotechnology. 2012, 32(07): 133-138.
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    Isoflavones were one class of secondary metabolites with C-6/C-3/C-6 skeleton, which possessed anti-oxidant and anti-tumor activities. Isoflavones and flavonoids had similar phenylpropanoid biosynthetic pathway. The majority of natural isoflavones occurred in leguminous plants. At present, more than 12 isoflavones were identified in soybean. The biosynthesis of soybean isoflvones mainly involved three key enzymes, which are CHS (chalcone synthase), CHI (chalcone isomerase), and IFS (isoflavone synthase). summarized The extraction and isolation methods and biosynthesis pathway of soybean isoflavones were summarized, and emphatically reviewed the biological characteristic and functions of CHI, CHS, and IFS as well as isoflovnes metabolic engineering were emphatically reviewed.
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