• Volume 24,Issue 9,2008 Table of Contents
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    • >Review
    • Research Progresses of Methanotrophs and Methane Monooxygenases

      2008, 24(9):1511-1519.

      Abstract (2581) HTML (0) PDF 561.41 K (7174) Comment (0) Favorites

      Abstract:Methanotrophs are a group of bacteria capable of utilizing methane as the sole carbon and energy source for their anabolism and catabolism. Since methanotrophs contain the unique enzymes of methane monooxygenases (MMOs), which can catalyze the oxidation of methane and short-chain alkanes and alkenes, they have potential applications in carbon recycle of nature and industrial biotechnology. Therefore, methanotrophs have been paid much more attention by the researchers in recent 20 years. In this paper, the latest progresses in studies of methanotrophs and MMOs were reviewed, including taxonomy, function and distribution of methanotrophs, and structure, function and genetic engineering of MMOs. The future research directions of methanotrophs and MMOs as well as their applications were also discussed.

    • >基因工程
    • Expression of Biologically Active Recombinant Arresten in Nicotiana tabacum

      2008, 24(9):1520-1525.

      Abstract (1400) HTML (0) PDF 526.61 K (3290) Comment (0) Favorites

      Abstract:In this report, the biological activity of the recombinant Arresten expressed in Nicotiana tabacum was studied. The gene coding for the tumor angiogenesis inhibitor Arresten was PCR-amplified from the plasmid pCA and its plant expression vector named pCAMBIAarr was constructed by inserting the Arresten cDNA fragment into the NcoI/BstEII sites of the plant binary expression vector pCAMBIA1301. Then pCAMBIAarr was transferred into Agrobacterium tumefacien LBA4404 by the freeze-thaw method. The adventitious shoots and regenerated plants of Nicotiana tabacum with hygromycinB-resistance were obtained via Agrobacterium-mediated leaf disk transformation method. Southern hybridization, RT-PCR and Western blotting analysis showed that the Arresten cDNA was integrated into the genome of some of the regenerated plants and the recombinant Arresten was expressed with a molecular size of 26 kD. Recombinant Arresten purified from transgenic tobacco leaves had an anti-proliferative effect on bovine endothelial cells. We speculate that biologically active recombinant Arresten can be produced by using plants as bioreactors.

    • Change of Hydrolase Activity in Germinating Seeds of trxS Transgenic Barley

      2008, 24(9):1526-1530.

      Abstract (2070) HTML (0) PDF 440.91 K (3008) Comment (0) Favorites

      Abstract:Genetic modification of barley variety can be an efficient way to improve beer quality. The objective of this study was to understand the effect of trxS gene on hydrolases activities in transgenic and non-transgenic barley seeds. The results showed that a-amylase, free b-amylase and limit dextrinase activity were increased in transgenic seeds in comparison with non-transgenic seeds. Sulfhydryl content of protein in transgenic seeds was also higher than that in non-transgenic seeds, suggesting that trxS gene could express in barley seeds, which opens a new way for breeding new barley varieties to improve beer quality.

    • Identification of Glucose-responsive Elements in the Promoter of UDP-L-rhamnose Biosynthesis Gene RHM1 in Arabidopsis thaliana

      2008, 24(9):1531-1537.

      Abstract (1996) HTML (0) PDF 589.70 K (3885) Comment (0) Favorites

      Abstract:In plants, UDP-L-rhamnose is one of the major components of cell wall skeleton. Rhamnose synthase plays a key role in rhamnose synthesis which converts UDP-D-glucose into UDP-L-rhamnose in plants. In this study, we isolated the 1058 bp promoter region of the rhamnose synthase gene AtRHM1 from Arabidopsis genome by PCR, and created a series of deletions of AtRHM1 promoter ranging from -931 bp to +127 bp. The full length of the promoter and its deletion derivatives fused with GUS reporter gene were introduced into wild-type Arabidopsis by Agrobacterium-mediated transformation respectively. The GUS staining and GUS enzymatic activity assay showed that the expression of AtRHM1 is induced at transcriptional level by glucose and the regulatory elements involved in the glucose response are located in the region of -931 bp ~ -752 bp which contains three G-box motifs.

    • A Successive Three-step ‘Gap-repair’ Method to Generate the mWAP-hLF Hybrid Gene Locus

      2008, 24(9):1538-1544.

      Abstract (1662) HTML (0) PDF 617.69 K (3576) Comment (0) Favorites

      Abstract:To generate a mWAP-hLF hybrid locus that the transcription of human lactoferrin(hLF) genomic sequence is directed by the up&down stream regulatory sequence of murine whey acidic protein (mWAP) gene locus, we describe here a successive three-step ‘Gap-repair’ method. First, a gap-repair vector based on pBR322 vector backbone by inserting six joint homologous arms was constructed. Then using ‘Gap-repair ’method mediated by Red recombination system of l-prophage in Escherichia coli, in the first step, the 8 kb 3¢ flanking region of the mWAP gene was subcloned from the Bacterial artificial chromosome which harbors the mWAP gene locus(mWAP BAC) into the gap-repair vector; in the second step, the 29 kb hLF genomic sequence from the ATG code to the TAA code was subcloned from the hLF BAC; in the third step, the 12 kb 5¢ flanking region of the mWAP gene was subcloned from the mWAP BAC. Finally, all these three DNA fragments were automatically combined together without any gap in the gap-repair vector, and a 49 kb mWAP-hLF hybrid locus that the hLF genomic sequence was flanked by the 5¢ & 3¢ flanking region of mWAP gene locus was constructed. The result was confirmed by PCR、restriction enzyme digestion and sequencing. Our method provide a new way for the construction of large mammary-gland expression vector.

    • Cloning, Expression and Purification of KDR Tyrosine Kinase

      2008, 24(9):1545-1549.

      Abstract (1672) HTML (0) PDF 504.88 K (3657) Comment (0) Favorites

      Abstract:The catalytic domain of KDR kinase (KDR-CD) was amplified from RNA of HUVCEs cells with RT-PCR and expressed in E. coli BL21(DE3) by plasmid pET30a as vector. The recombinant protein was purified with affinity chromatography (Ni-NTA). Western blotting showed that the recombinant KDR-CD was phosphorylated in E. coli BL21(DE3). The recombinant KDR-CD was identified to have kinase activity catalyzing the substrate phosphorylated with ATP in the enzymatic reaction.

    • Cloning, Expressing and Characterizing of a Phosphoglycerate mutas Gene of Schistosoma japonncum

      2008, 24(9):1550-1555.

      Abstract (1714) HTML (0) PDF 717.16 K (3708) Comment (0) Favorites

      Abstract:Phosphoglycerate mutase (PGAM) is a key enzyme in glycolytic pathways. With PCR technique based on an EST identified in our lab, a novel gene named SjPGAM (GenBank Accession No. EU374631) was cloned. Sequence analysis revealed that the ORF of SjPGAM gene contained 753 nucleotides, encoding 250 amino acids, and the molecular weight was about 28.26 kD. Real-time PCR analysis showed that the mRNA level of SjPGAM was much higher in the 14 days and 19 days schistosomula than other stages, suggesting that the gene was a schistosomula stage differential expression gene. The SjPGAM cDNA fragment was subcloned into an expression vector pET-28a (+) and transformed into Escherichia coli BL21 cells. In the presence of IPTG, the 31 kD fusion protein was expressed in included bodies. Western blotting revealed that the fusion protein could be recognized by the rabbit serum anti-Schistosoma japonicum adult worm antigen preparation. The study provides important basis for investigating the mechanism of the PGAM in the glycolytic pathways of Schistosoma japonnicum.

    • Comparison of Antiviral Activitt Between feIFN-w and feIFN-a

      2008, 24(9):1556-1560.

      Abstract (2867) HTML (0) PDF 614.57 K (5880) Comment (0) Favorites

      Abstract:Both IFN-ω and IFN-α belong to type I interferon and have antiviral, antiproliferative, immunomodulatory activities, but their bioactivities are usually different. FeIFN-w gene was amplified by PCR. FeIFN-a gene was synthesized based on the published sequences of GenBank. Then the two types of feline interferon genes were subcloned into the pET-His vector, and expressed in Escherichia coli Rosetta (DE3). Recombinant interferons were purified by affinity chromatography with immobilized nickel chelating NTA (Ni-NTA) and their antiviral activity was estimated according to the ability of IFNs to inhibit the cytopathic effects (CPE) of virus on cells. Results showed that the antiviral activities against various viruses of feIFN-w were higher than those of feIFN-a. Against H9N2 subtype avian influenza virus (AIV) and canine distemper virus (CDV), the antiviral activities of feIFN-w were 160 folds and 4 folds higher than those of feIFN-a.

    • Cloning, Expression and Immunity of pilA Gene and ompC Gene from Avian Pathogenic Escherichia coli

      2008, 24(9):1561-1567.

      Abstract (1678) HTML (0) PDF 620.30 K (3473) Comment (0) Favorites

      Abstract:In order to amplify pilA gene and ompC gene of avian pathogenic Escherichia coli (APEC) strain, two pairs of primers were designed according to the GenBank sequences, and a 549 bp pilA gene and a 1104 bp ompC gene were obtained by PCR separately. Sequence analysis indicated that the homology of the nucleotide sequence of AEPC strain to those other reference strains was 98.18% of the pilA gene and 97.28% of the ompC gene. Two expression plasmids pETpilA and pETompC were constructed by inserting pilA gene and ompC gene into the prokaryotic expression vector pET-28a. The two plasmids were transformated into E. coli BL21 separately and two recombinant strains BL21 (pETpilA) and BL21 (pETompC) were obtained. The type 1 fimbraie and the out membrane protein were highly expressed when the recombinant strain BL21 (pETpilA) and BL21 (pETompC) were induced by IPTG. Two specific proteins were detected by SDS-PAGE and immunogenicity of the expressed protein was confirmed by Western blotting and ELISA. The expressed fimbraie and OmpC were transformed into vaccine. The protective immune response was proved after the mice were immunized with the two vaccines. The results showed that the recombinant strain BL21 (pETpilA) and BL21 (pETompC) could be as candidate vaccine to provide protective immune response against AEPC infection.

    • Construction of Eukaryotic Express Vector of Duck Interleukin 18 Gene and Identification of Bioactivity of Its Expressed Protein

      2008, 24(9):1568-1572.

      Abstract (1812) HTML (0) PDF 519.28 K (3204) Comment (0) Favorites

      Abstract:Duck IL-18 gene was amplified from plasmid pGEM-DuIL-18 by PCR. The PCR product digested with Pst I and Xho I was inserted into eukaryotic express vector pcDNA3.1(+) to generate an recombinant expression plasmid pcDNA3.1/DuIL-18 (pDuIL-18), and transformed into Escherichia coli JM109. The recombinant colonies were identified by restriction enzyme digestion, PCR and sequencing. DNA sequence confirmed the correct sequence of the recombinant eukaryotic expression plasmid pDuIL-18 in the reading frame and the ligation part. After the transfection of pDuIL-18 into Cos7 cells, duck IL-18 mRNA was expressed in Cos7 cel1. The SDS-PAGE analysis showed that the expressed duck IL-18 protein had molecular weight of 23 000 D. The results of methyl thiazolyl tetrazolium (MTT) assay showed that duck IL-18 protein expressed in Cos7 cell could induce significantly transformation of duck T lymphocytes. Immunoenhancement effect of recombinant expression plasmid pDuIL18 on avian influenza vaccine was observed by proliferation response of the T lymphocytes from spleen. It can obviously enhance the cell-mediated immune response.

    • Construction and Application of Chimeric Infectious Clones of Porcine Reproductive and Respiratory Syndrome Virus

      2008, 24(9):1573-1581.

      Abstract (1745) HTML (0) PDF 599.89 K (3954) Comment (0) Favorites

      Abstract:In recent years, mass outbreaks of highly pathogenic (HP) porcine reproductive and respiratory syndrome virus (PRRSV) have spread all over the Chinese swine industry. Based on the first infectious cDNA clone of HP PRRSV strain pJX143 and that of an attenuated PRRSV, pAPRRS, constructed in our group, we constructed several chimeric clones with various substitutions of structural protein genes (ORF4-7) and 3¢ UTR between attenuated pAPRRS and virulent pJX143.Upon transfection of MA-104 cultured cells, all chimeric constructs pSX12, p5NX12, and p56N12 were rescued. The rescued viruses maintained the similar virological properties, based on the results of the growth curve of the rescued viruses. To test if the chimeric viruses can be used as a vaccine candidate, vSX12 and v56N12 vaccinated pigs were challenged with the HP PRRSV JX143 strain. As a result, the vSX12 vaccinated pigs were all seroconverted by 14-day-post vaccination, while v56N12 vaccinated pigs showed poor antibody response. Upon challenge, the vSX12-vaccinated group showed no signs of clinical PRRS syndrome, and virema period was shorten to 6 days post-challenge. Our results demonstrated that 1) vSX12 chimeric virus is a good vaccine candidate; 2) the virulence determinants of HP PRRSV probably located in coding regions other than ORF3-7 and 3¢ UTR, as our chimeric viruses were proved to be attenuated.

    • >细胞工程
    • Differentiation of Human Amniotic Fluid Stem Cells into Cardiomyocytes through Embryonic Body Formation

      2008, 24(9):1582-1587.

      Abstract (1831) HTML (0) PDF 581.91 K (4108) Comment (0) Favorites

      Abstract:To isolate human amniotic fluid stem cells (hASCs) and induce hASCs into cardiomyocytes after forming the embryonic bodies. We cultivated hASCs isolated from the amniotic fluid continually for over 42 passages. The biological characteristics of hASCs were detected by immunocytochemistry, RT-PCR and flow cytometer. hASCs at 10~15th passage were suspension cultured to form embryonic bodies that were induced to cardiomyocytes. Fibroblastoid-type hASCs were obtained. Immunocytochemistry, RT-PCR and flow cytometry analysis demonstrated that hASCs were positive for some specific makers of the embryonic stem cell. hASCs could form embryonic bodies that were alkaline-phosphatase positive and expressed fgf5, ζ-globin and α-fetoprotein. The embryonic bodies could differentiate into cardiomyocytes showing α-actin positive and Tbx5, Nkx2.5, GATA4 and α-MHC positive. We conclued that hASCs obtained from human amniotic fluid could differentiate into cardiomyocytes through the formation of embryonic bodies.

    • Hematopoietic Repopulating Ability of Human CD34+ Cells and CD34- Cells in NOD/SCID Mice

      2008, 24(9):1588-1594.

      Abstract (2026) HTML (0) PDF 510.31 K (6005) Comment (0) Favorites

      Abstract:The hematopoietic repopulating ability of fresh and cultured CD34+ cells and CD34- cells derived from cord blood were compared by nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mouse model. Fresh CD34+ cells and CD34- cells were isolated from fresh cord blood. Cultured CD34+ cells and CD34- cells were separated from cultured mononuclear cells (MNC). We transplanted these cells into sublethally irradiated NOD/SCID mice via the tail vein and sacrificed surviving mice after 6 weeks. The peripheral blood, spleen and bone marrow from each mouse were harvested for flow cytometry, colony-forming cells and human Alu sequences analyses. The proportions of CD45+ cells and human multilineage hematopoietic cells in NOD/SCID mice received CD34+ cells were close to that in the mice received both CD34+ cells and CD34- cells, while it was significantly higher than that in the mice received CD34- cells. Six weeks after transplantation, all the mice injected with cultured CD34- cells dead. The survival rate of mice injected with cultured CD34+ cells was 66.7%. All of the mice injected with both cultured CD34- and CD34+ cells survived. Moreover, CD45+ cells could be detected in all surviving mice, and human CD34, CD3, CD19, CD33 and CD71 antigen also could be detected on these CD45+ cells. The results showed that both fresh and cultured CD34+ cells had the capability of engraftment and hematopoiesis reconstitution, but CD34- cells hadn’t the ability. However, CD34- cells had assistant effect on the hematopoietic repopulating ability of CD34+ cells.

    • Breeding of Actinobacillus Succiniogenes Mutants with Improved Succinate Production Based on Metabolic Flux Analysis

      2008, 24(9):1595-1603.

      Abstract (2008) HTML (0) PDF 724.64 K (3620) Comment (0) Favorites

      Abstract:It is very important to obtain high yield mutant strains on the base of metabolic flux analysis of Actinobacillus succinogenes S.JST for the industrial bioconversion of succinic acid. The metabolic pathway was analized at first and the flux of the metabolic networks was calculated by matrix. In order to decrease acetic acid flux, the strains mutated by soft X-ray of synchronous radiation were screened on the plates with high concentration of fluoroacetic acid. For decreasing the metabolic flux of ethanol the site-directed mutagenesis was carried out for the reduction of alcohol dehydrogenase(Adh) specific activity. Then the enzyme activity determination and the gene sequence analysis of the mutant strain was compared with those of the parent strain. Metabolic flux analysis of the parent strain indicated that the fulx of succinic acid was 1.78 (mmol/g/h) and that the flux of acetic acid and ethanol were 0.60 (mmol/g/h) and 1.04( mmol/g/h), respectively. Meanwhile the metabolic pathway analysis showed that the ethanol metabolism enhanced the lacking of H electron donor during the synthesis of succinic acid and that the succinic acid flux was weakened by the metabolism of byproducts ethanol and acetic acid. Compared with the parent strain, the acetic acid flux of anti-fluoroacetic mutant strain S.JST1 was 0.024( mmol/g/h), decreasing by 96%. Then the enzyme determination showed that the specific activity unit of phosphotransacetylase(Pta) decreased from 602 to 74 and a mutated site was founded in the pta gene of the mutant strain S.JST1. Compared with that of the parent strain S.JST1 the ethanol flux of adh-site-directed mutant strain S.JST2 was 0.020 (mmol/g/h), decreasing by 98%. Then the enzyme determination showed that the specific activity unit of Adh decreased from 585 to 62 and the yield of end product succinic acid was 65.7 (g/L). The interdiction of Adh and Pta decreased the metabolism of byproducts and the H electron donor was well balanced, thus the succinic acid flux was strengthened by the redundant carbon flux from these byproducts. The mutant strain S.JST2 obtained in this paper deserves being extended to application of industrial fermentation.

    • Influences of Phosphate Deficiency in the Medium on Growth, Activities of Antioxidant Enzymes and Utilization of Nitrogen Resource in Cucumis sativus Hairy Roots

      2008, 24(9):1604-1612.

      Abstract (1474) HTML (0) PDF 544.44 K (3175) Comment (0) Favorites

      Abstract:Effects of phosphorus deficiency in the medium on growth and morphology and activities of SOD and POD, utilization of nitrogen and calcium in the medium during liquid culture of Cucumis sativus hairy roots were investigated. The results showed that C. sativus hairy roots can not grow in the medium without addition of any phosphorus. When cultured into the medium with different Pi concentrations, the growth of C. sativus hairy roots was significantly inhibited with the decreasing of Pi concentration in the medium, its main roots became thinner and longer, the number of its lateral roots was decreased and its lateral roots became shorter and smaller. Compared to the medium with full strength phosphorus, the content of soluble proteins in C. sativus hairy roots cultured under Pi deficiency was significantly lower than that with standard full-length Pi, while POD and SOD activities in C. sativus hairy roots were significantly stimulated. Compared to the control (without addition of any phosphorus in the medium), the activities of POD and SOD in C. sativus hairy roots cultured in the medium with different concentration of Pi were lower than the control. When C. sativus hairy roots were cultured into medium with different Pi concentrations, the medium conductivity was gradually decreased with time and with direct proportion of the initial Pi concentration of the medium; NH4+-N and NO3--N of the medium was gradually absorbed and utilized, at day 15, NH4+-N of the medium was nearly used up but its NO3--N was not used up until cultured for 30 days. Pi deficiency in the medium could decrease the consumption rate of NO3--N and inhibited the absorption and utilization of calcium of the medium by C. sativus hairy roots. Proper enhancement of Pi concentration could stimulate absorption and consumption of calcium of the medium.

    • >Metabolic Engineering
    • Effects of Leptin on Porcine Primary Adiocytes Lipolysis and mRNA Expression of Key Lipolytic Enzymes

      2008, 24(9):1613-1619.

      Abstract (1403) HTML (0) PDF 659.00 K (3600) Comment (0) Favorites

      Abstract:Leptin, a cytokine predominantly secreted from fat tissue, plays an important role in regulating organism energy balance. Leptin can stimulate lipolysis, but the mechanism is unclear. In order to study the molecular mechanism of leptin stimulating lipolysis, we systemically studied the mRNA expression of key lipolytic enzymes. Morphological observation, Oil Red O staining and RT- PCR were used to identify pig primary adipocytes; commercial kits were used to measure the glycerol and FFA release; Semiquantitative RT-PCR was used to detect the mRNA expression of key lipolytic enzymes. The results showed that 100 nmol/L leptin up-regulated the mRNA expression of ATGL, TGH-2, HSL, MGL and LPL (P<0.01), but down-regulated the Perilipin mRNA expression (P<0.01). At the same time, leptin promoted the glycerol release in a dose dependent manner (P<0.01), but had no effect on the FFA release (P>0.05). These indicate that leptin may mainly stimulate lipolysis in pig primary adipocytes by up-regulating the expression of ATGL, MGL, LPL and down-regulating the expression of Perilipin. The unchanged FFA release may be resulted from Leptin promoting UCPs mRNA expression and increasing FFA expenditure.

    • >SHORT COMMUNICATIONS
    • Cloning of PTD-NPY Fusion Gene and Its Secretory Expression in Pichia pastoris

      2008, 24(9):1620-1624.

      Abstract (1751) HTML (0) PDF 581.84 K (3233) Comment (0) Favorites

      Abstract:The PTD-NPY fusion gene derived from HIV-1 TAT protein transduction domain and rat neuropeptide Y was amplified by overlap extension PCR, digested and subcloned into yeast expression vector pPICZaA to construct recombinant expression plasmid pPICZa-PTD-NPY. The cloned PTD-NPY fusion gene was identified by PCR and restriction enzyme digestion and sequenced. The exact recombinant plasmid was linearized by Sac I and integrated by electrotransformation into the genome of Pichia pastoris GS115 cells. Then, these positive recombinant yeast cells were induced by 10 mL/L methanol to express soluble PTD-NPY fusion protein. After 120 h of methanol induction, the SDS-PAGE electrophoresis result indicated PTD-NPY fusion protein was efficiently secreted into the medium. Western blotting analysis proved that the expressed fusion protein had specific NPY binding activity. The successful expression of PTD-NPY fusion protein in Pichia pastoris provided basis for its further application study.

    • Cloning, Expression and Antiviral Activity of Arctic Fox (Alopex lagopus) Interferon-g Gene

      2008, 24(9):1625-1630.

      Abstract (1519) HTML (0) PDF 767.63 K (3636) Comment (0) Favorites

      Abstract:In order to characterize the biological activity of fox (Vulpes vulpes) interferon gamma(VuIFN-g), We have isolated the cDNA encoding arctic fox(Alopex lagopus)VuIFN- g. This cDNA encodes a 23 amino acid signal peptide and a 144 amino acid mature protein, which shares 99.8% or 99.4% for nucleotide identity with silver fox and canine, respectively, and 100% for amino acid identity. Expression of recombinant mature arctic fox interferon gamma (mVuIFN-g) in bacterial system was confirmed by SDS-PAGE and Western blotting analysis. Recombinant VuIFN-g showed higher antiviral activity against vesicular stomatitis virus in cultured Vero and MDCK by inhibiting virus induced cytopathic effect, In view of the immunomodulatory and antiviral activities of VuIFN-g, it may provide a basis for further research on antiviral therapy of recombinant VuIFN-g in economic animal practice.

    • Relationship between Structure and Function of Loops from Bacillus thuringiensis Insecticidal Crystal Protein Cry1Ba

      2008, 24(9):1631-1636.

      Abstract (1376) HTML (0) PDF 483.00 K (3087) Comment (0) Favorites

      Abstract:To indicate the relationship between structure and function of loops from Bacillus thuringiensis insecticidal crystal protein Cry1Ba, and the influence of amino acids mutation on toxicity against diamond back moth Plutella xylostella, five mutations at the loops of Cry1Ba were constructed by overlapping primer PCR, and expressed in E. coli BL21 (DE3). Bioassay results showed that the toxicity of mutation M1 (loop1: 340WSNTR344-deletion), compared with that of Cry1Ba (LC50 0.96 mg/mL), decreased significantly with LC50 35.51 mg/mL. And the toxicity of mutation M2 (402Y-G), M3 (400GIYLEP405-PSAV), M4 (400GIYLEPIH407-ILGS) was also reduced to some extent respectively. Only M5 (mutation at loop3: 472LQSRV476 - AGAVYTL) showed slightly increased activity against P. xylostella, but not significantly (LC50 0.81 mg/mL). Referring to the structures of Cry1Ba which was predicted using Swiss-Model software, and bioassay data, we can conclude that loop1 and loop2 play a important role on determining the activity of Cry1Ba against P. xylostella.

    • Effect of Organic Solvent on Production of Organic Acids from Municipal Sludge

      2008, 24(9):1637-1642.

      Abstract (1417) HTML (0) PDF 515.57 K (3141) Comment (0) Favorites

      Abstract:Organic acids are important chemicals. Municipal sludge can be reused by anaerobic fermentation, from which organic acids could be obtained with liquid-liquid extraction and useful substances be produced. Based on the determination of optimum organic solvent and extractant, it effect on production of volatile fatty acid (VFA) from municipal sludge was investigated in this research. The results showed that the proper organic solvent and extractant were sulfonated kerosene and trialkyl phosphine oxide. And, the VFA production was improved by a slight amount of sulfonated kerosene.

    • Relativity of Gene Expression and Co-regulated Gene Patterns in Feature KEGG Pathways

      2008, 24(9):1643-1648.

      Abstract (1927) HTML (0) PDF 477.54 K (4181) Comment (0) Favorites

      Abstract:We revealed the feature pathways by computing the classification error rates of out-of-bag (OOB) by random forests combined with pathway analysis. At each feature pathway, the relativity of gene expression was studied and the co-regulated gene patterns under different experiment conditions were analyzed by MAP (Mining attribute profile) algorithm. The discovered patterns were also clustered by the average-linkage hierarchical clustering technique. The results showed that the expression of genes at the same pathway was similar. The co-regulated patterns were found in two feature pathways of which one contained 108 patterns and the other contained 1 pattern. The results of clusters showed that the smallest Pearson coefficient of the clusters was more than 0.623, indicating that the co-regulated patterns in different experiment conditions were more similar at the same KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway. The methods can provide biological insight into the study of microarray data.

    • Expression and Identification of PEBP-like Gene from Saussurea involucrate Kar.er kir in Escherichia coli

      2008, 24(9):1649-1652.

      Abstract (1513) HTML (0) PDF 506.45 K (2991) Comment (0) Favorites

      Abstract:This assay was designed to construct the prokaryotic expression vector, investigate the expression of PEBP-like in Escherichia coli and purify its product. The PEBP gene was inserted into the vector pET30a (+). The recombinant vector was transferred into E. coli BL21 (DE3)and induced the expression of protein by low concentration of IPTG and low temperature overnight. After purification, the supernatants were analyzed by SDS-PAGE and the results were identified by Western blotting. After IPTG induction, a new anticipating fusion protein of 28 kD appeared as an expected size, and its product was 26.8% in total protein, the fusion protein was positive by Western blotting. The prokaryotic expression system of PEBP-like is successfully constructed. It lays the foundation for the further application study on the antifreeze characters of the PEBP.

    • >TECHNIQUES AND METHODS
    • Establishment of Human IFN-g in vitro Release Assay and Its Application in Tuberculosis Diagnosis

      2008, 24(9):1653-1657.

      Abstract (1500) HTML (0) PDF 488.59 K (4759) Comment (0) Favorites

      Abstract:This study aimed to establish human IFN-g (hIFN-g) in vitro release assay and to apply it in diagnosis of human tuberculosis. Human IFN-g gene was cloned and expressed in Escerichia coli. The recombinant hIFN-g was purified and used as immunogen to immunize mice and rabbits respectively. Monoclonal and polyclonal antibodies were respectively developed and a sandwich ELISA was established. The heparized whole blood from 111 active tuberculosis patients and 292 clinical healthy controls were collected. The blood was stimulated with tuberculosis specific fused antigen ESAT-6/CFP-10 and the plasma was collected for IFN-g detection. The sensitivity for tuberculosis diagnosis was 95.5%, whereas the positive detection rate for the healthy controls was 16.7%. There was a significant difference between the patients and healthy controls (P<0.01) indicating that this assay had a high sensitivity and specificity, and thus could be promising in tuberculosis diagnosis.

    • Interferon a-2b Modified with Polyethylene Glycol

      2008, 24(9):1658-1663.

      Abstract (1847) HTML (0) PDF 598.34 K (4642) Comment (0) Favorites

      Abstract:In order to obtain a more stable PEGylated interferon a-2b, and prolong its half life, interferon a-2b(IFN a-2b) was modified with monomethoxy polyethylene glycol propionaldehyde (mPEG-ALD) 20000. It was found that the optimized reaction condition for the maximum bioactivity and highest PEGylation degree of the mono PEGylated interferon a-2b was as follows: in 20 mmol/L, pH 6.5, citric acid and sodium dihydrogen phosphate buffer, the concentration of IFN a-2b was 4 mg/mL, and the molar ratio of PEG/IFN a-2b was 8:1, and the reaction time was 20 h at 4oC. Under the optimized reaction condition, the mono PEGylation degree reached to 55%. Ion exchange chromatography was used to separate and purify mono PEGylated interferon a-2b from the reaction mixture. The purity of mono PEGylated interferon a-2b was higher than 97% characterized by HPLC. The bioactivity of the mono PEGylated interferon a-2b was 13.4% of the native IFN a-2b, while its half life in SD rat is much longer than the native IFN a-2b. The mono PEGylated interferon a-2b is also stable in aqueous.

    • Preparation of Monoclonal Antibodies Against VP2 Protein of Asia I Type Foot-and-mouth Disease Virus and Establishment of a Competitive ELISA for the Detection of Antibodies

      2008, 24(9):1664-1669.

      Abstract (1556) HTML (0) PDF 582.75 K (3669) Comment (0) Favorites

      Abstract:Monoclonal antibodies against FMDV vp2 protein were prepared and a competitive ELISA based on the monoclonal antibodies and vp2 protein was established. Balb/c mice were immunized with Escherichia coli expressed fusion protein. The splenocytes from immunized mice were fused with myeloma cells SP2/0. The hybridism cells were screened by indirect ELlSA and limited dilution method. Two hybndoma cell Iines secreting mAbs against Asia I type foot-and-mouth disease were obtained. The titer and relative affinity of mAbs were determined by ELISA. Specificity of mAbs was analyzed by Western blotting. The ELISA titers of the ascites induced by the two hybridism cells were above 100×29.A competitive ELISA for the use of FMDV antibody detection was established using E. coli expressed fusion protein as coating antigen and HRP-labled mAb as detecting antibody. Clinical tests showed the method had 89.0 percent agreement with UBI Kit to detection of FMDV antibodies and 86.5 percent agreement with LPB- ELISA kit (Ceditest kit) for detection of antibodies against Foot-and-Mouth Disease Virus respectively.

    • Isolation and Cultivation of Goat Embryo Stem Cells

      2008, 24(9):1670-1676.

      Abstract (1451) HTML (0) PDF 938.19 K (3646) Comment (0) Favorites

      Abstract:Morulaes and blastocysts obtained from Guanzhong dairy goats 6~7 days after mating were treated with whole embryo cultivaton, enzymatic digestion and immunosurgery separately. The goat embryonic stem cells (ESC) were isolated and cultured on a feeder layer of mitomycin-inactivated mouse embryo fibroblasts (MEF). The characteristics of goat ESCs were analyzed by immunohistochemisty, RT-PCR and inducing differentiation in vitro. The results indicated that the embryos were easier to attach the culture dish and form primary colonies with whole embryo method. There were colonies that maintained undifferentiated for 18 passages. The ESCs expressed the protein of Nanog, Oct4 and SSEA-3, whereas the protein of SSEA-4 was absent and the protein of SSEA-1 was weakly expressed. In addition, the genes of Nanog, Oct4, TERT and CD117 were expressed in goat ESCs. The cells also could differentiate to myocardial cells when induced in vitro by DMSO. These results suggest that the goat ESCs have characteristics of ESCs.

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