Kexuan Tang

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (238)412.51 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Artemisia annua is widely studied for its ability to accumulate the antimalarial sesquiterpenoid artemisinin. In addition to producing a variety of sesquiterpenoids, A. annua also accumulates mono-, di-, and triterpenoids, the majority of which are produced in the glandular trichomes. A. annua also has filamentous trichomes on its aerial parts, but little is known of their biosynthesis potential. Here, through a comparative transcriptome analysis between glandular and filamentous trichomes, we identified two genes, OSC2 and CYP716A14v2, encoding enzymes involved in the biosynthesis of specialized triterpenoids in A. annua. By expressing these genes in Saccharomyces cerevisiae and Nicotiana benthamiana, we characterized the catalytic function of these proteins and could reconstitute the specialized triterpenoid spectrum of A. annua in these heterologous hosts. OSC2 is a multifunctional oxidosqualene cyclase that produces α-amyrin, β-amyrin, and δ-amyrin. CYP716A14v2 is a P450 belonging to the functionally diverse CYP716 family and catalyzes the oxidation of pentacyclic triterpenes, leading to triterpenes with a carbonyl group at position C-3, thereby providing an alternative biosynthesis pathway to 3-oxo triterpenes. Together, these enzymes produce specialized triterpenoids that are constituents of the wax layer of the cuticle covering the aerial parts of A. annua and likely function in the protection of the plant against biotic and abiotic stress. © 2015 American Society of Plant Biologists. All rights reserved.
    The Plant cell. 01/2015;
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    ABSTRACT: Artemisinin is a sesquiterpenoid especially synthesized in the Chinese herbal plant, Artemisia annua, which is widely used in the treatment of malaria. Artemisinin accumulation can be enhanced by exogenous abscisic acid (ABA) treatment. However, it is not known how ABA signaling regulates artemisinin biosynthesis. A global expression profile and phylogenetic analysis as well as the dual-LUC screening revealed that a basic leucine zipper family transcription factor from A. annua (namely AabZIP1) was involved in ABA signaling to regulate artemisinin biosynthesis. AabZIP1 had a higher expression level in the inflorescences than in other tissues; ABA treatment, drought, and salt stress strongly induced the expression of AabZIP1. Yeast one-hybrid assay and electrophoretic mobility shift assay (EMSA) showed that AabZIP1 bound to the ABA-responsive elements (ABRE) in the promoter regions of the amorpha-4,11-diene synthase (ADS) gene and CYP71AV1, which are two key structural genes of the artemisinin biosynthetic pathway. A mutagenesis assay showed that the C1 domain in the N-terminus of AabZIP1 was important for its transactivation activity. Furthermore, the activation of ADS and CYP71AV1 promoters by AabZIP1 was enhanced by ABA treatment in transient dual-LUC analysis. The AabZIP1 variant with C1 domain deletion lost the ability to activate ADS and CYP71AV1 promoters regardless of ABA treatment. Notably, overexpression of AabZIP1 in A. annua resulted in significantly increased accumulation of artemisinin. Our results indicate that ABA promotes artemisinin biosynthesis, likely through 1 activation of ADS and CYP71AV1 expression by AabZIP in A. annua. Meanwhile, our findings reveal the potential value of AabZIP1 in genetic engineering of artemisinin production.
    Molecular Plant. 01/2015; 8(1):163-175.
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    ABSTRACT: Quantitative PCR (qPCR) is a powerful tool for measuring gene expression levels. Accurate and reproducible results are dependent on the correct choice of reference genes for data normalization. Atropa belladonna is a commercial plant species from which pharmaceutical tropane alkaloids are extracted. In this study, eight candidate reference genes, namely 18S ribosomal RNA (18S), actin (ACT), cyclophilin (CYC), elongation factor 1α (EF-1α), β-fructosidase (FRU), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase (PGK), and beta-tubulin (TUB), were selected and their expression stabilities studied to determine their suitability for normalizing gene expression in A. belladonna. The expression stabilities of these genes were analyzed in the root, stem, and leaf under cold, heat, NaCl, UV-B, methyl jasmonate, salicylic acid, and abscisic acid treatments using geNorm, NormFinder, and BestKeeper. The statistical algorithms indicated that PGK was a reliable gene for normalizing gene expression under most of the experimental conditions. The pairwise value analysis showed that two genes were sufficient for proper expression normalization, except when analyzing gene expression in heat-treated roots. However, the choice of the second reference gene depended on specific conditions. Finally, the relative expression level of the PMT gene of A. belladonna was detected to validate the selection of PGK a reliable reference gene. In summary, our results should guide the selection of appropriate reference genes for gene expression studies in A. belladonna under different organs and abiotic stress conditions.
    Plant Molecular Biology Reporter 10/2014; 32(5). · 2.37 Impact Factor
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    ABSTRACT: Amorpha-4,11-diene synthase (ADS) is the first key enzyme of artemisinin biosynthetic pathway in Artemisia annua L. In this study, the promoter region of the ADS gene has been cloned and used to demonstrate the expression of GUS reporter gene in both glandular trichomes of A. annua and non-glandular trichomes of Arabidopsis thaliana following homologous and heterologous expression of ADS promoter–GUS fusion. Subsequently, 5′ sequential deletion analysis of the ADS promoter revealed that a short sequence, −350 upstream of the transcription start site, was sufficient for trichome-specific expression in A. thaliana and that the region from −350 to −300 contained essential elements for this observed specificity. However, frequencies of transgenic A. thaliana plants displaying trichome-specific expressions varied between different lines, and all the lines with deleted fragments of the ADS promoter showed lower frequencies than the line with full-length ADS promoter. Most lines with deleted ADS promoter–GUS fusions showed GUS expressions in the guard cells of stomata as well, which was not observed in A. thaliana plants transformed with the full-length ADS promoter. GUS activities varied among different transgenic lines as well, both in transiently transformed Nicotiana benthamiana and stably transformed A. thaliana, with promoter–deletion lines exhibiting higher GUS activities than the full-length ADS promoter line.
    Plant Molecular Biology Reporter 04/2014; 32(2). · 2.37 Impact Factor
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    ABSTRACT: Jasmonates (JAs) are important signaling molecules in plants and play crucial roles in stress responses, secondary metabolites' regulation, plant growth and development. In this study, the promoter of AaAOC, which was the key gene of jasmonate biosynthetic pathway, had been cloned. GUS staining showed that AaAOC was expressed ubiquitiously in A. annua. AaAOC gene was overexpressed under control of 35S promoter. RT-Q-PCR showed that the expression levels of AaAOC were increased from 1.6- to 5.2-fold in AaAOC-overexpression transgenic A. annua. The results of GC-MS showed that the content of endogenous jasmonic acid (JA) was 2- to 4.7-fold of the control level in AaAOC-overexpression plants. HPLC showed that the contents of artemisinin, dihydroartemisinic acid and artemisinic acid were increased significantly in AaAOC-overexpression plants. RT-Q-PCR showed that the expression levels of FPS (farnesyl diphosphate synthase), CYP71AV1 (cytochrome P450 dependent hydroxylase) and DBR2 (double bond reductase 2) were increased significantly in AaAOC-overexpression plants. All data demonstrated that increased endogenous JA could significantly promote the biosynthesis of artemisinin in AaAOC-overexpression transgenic A.annua.
    PLoS ONE 03/2014; 9(3):e91741. · 3.53 Impact Factor
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    ABSTRACT: A major challenge for further promotion of lipase productivity in Penicillium expansum PE-12 is to find a suitable promoter that can function efficiently in this industrial strain. In this study, the 5' flanking region of P. expansum lipase (Ppel) containing a putative novel promoter sequence was characterized by fusing to β-glucuronidase (GUS) and subsequently introducing into P. expansum. As a result, all the transformants showed blue color quickly, after incubation in GUS detection buffer, suggesting a strong promoter activity of this fragment. Glucose repression was identified for the promoter, whereas olive oil acted as a positive regulator. Facilitated by this novel promoter, P. expansum PE-12 was genetically modified, with an improved lipase yield, via a recombinant plasmid with P. expansum lipase gene (PEL) under the control of Ppel promoter and TtrpC terminator. The highest lipase yield among the modified strains could attain 2100 U/mL, which is more than 2-fold of the previous industrial strain (900 U/mL). The engineered strain through molecular breeding method as well as this new promoter has great value in lipase industry. This article is protected by copyright. All rights reserved.
    Biotechnology and Applied Biochemistry 02/2014; · 1.35 Impact Factor
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    ABSTRACT: Artemisinin is widely used as an antimalarial drug around the world. Artemisinic aldehyde Δ11(13) reductase (DBR2) is a key enzyme which reduces artemisinic aldehyde to dihydroartemisinic aldehyde in the biosynthesis of artemisinin. In this study, two fragments encompassing a putative promoter of DBR2, designated as DBR2pro1 and DBR2pro2, were isolated using genomic DNA walking. The transcription start site and the putative cis-elements of each version of promoter were predicted using bioinformatic analysis. In order to study the function of the cloned promoter, Artemisia annua was transformed with β-glucuronidase (GUS) reporter gene driven by DBR2pro1 and DBR2pro2, respectively. GUS staining results demonstrated that both DBR2pro1 and DBR2pro2 were strongly expressed in glandular secretory trichomes (GSTs) of leaf primordia and flower buds, but were not obviously expressed in roots, stems, old leaves, and fully developed flowers, thus indicating that the two versions of promoter were functional and specifically expressed in GSTs.
    Plant Molecular Biology Reporter 02/2014; · 2.37 Impact Factor
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    ABSTRACT: Artemisinin, the endoperoxide sesquiterpene lactone, is an effective antimalarial drug isolated from the Chinese medicinal plant Artemisia annua L. Due to its effectiveness against multi-drug-resistant cerebral malaria, it becomes the essential components of the artemisinin-based combination therapies which are recommended by the World Health Organization as the preferred choice for malaria tropica treatments. To date, plant A. annua is still the main commercial source of artemisinin. Although semi-synthesis of artemisinin via artemisinic acid in yeast is feasible at present, another promising approach to reduce the price of artemisinin is using plant metabolic engineering to obtain a higher content of artemisinin in transgenic plants. In the past years, an Agrobacterium-mediated transformation system of A. annua has been established by which a number of genes related to artemisinin biosynthesis have been successfully transferred into A. annua plants. In this review, the progress on increasing artemisinin content in A. annua by transgenic approach and its future prospect are summarized and discussed.
    Plant Cell Reports 01/2014; · 2.94 Impact Factor
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    ABSTRACT: The phytohormone abscisic acid (ABA) plays an important role in plant development and environmental stress response. Additionally, ABA also regulates secondary metabolism such as artemisinin in the medicinal plant Artemisia annua L. Although an earlier study showed that ABA receptor, AaPYL9, plays a positive role in ABA-induced artemisinin content improvement, many components in the ABA signaling pathway remain to be elucidated in Artemisia annua L. To get insight of the function of AaPYL9, we isolated and characterized an AaPYL9-interacting partner, AaPP2C1. The coding sequence of AaPP2C1 encodes a deduced protein of 464 amino acids, with all the features of plant type clade A PP2C. Transcriptional analysis showed that the expression level of AaPP2C1 is increased after ABA, salt, and drought treatments. Yeast two-hybrid and bimolecular fluorescence complementation assays (BiFC) showed that AaPYL9 interacted with AaPP2C1. The P89S, H116A substitution in AaPYL9 as well as G199D substitution or deletion of the third phosphorylation site-like motif in AaPP2C1 abolished this interaction. Furthermore, constitutive expression of AaPP2C1 conferred ABA insensitivity compared with the wild type. In summary, our data reveals that AaPP2C1 is an AaPYL9-interacting partner and involved in the negative modulation of the ABA signaling pathway in A. annua L.
    BioMed Research International 01/2014; 2014:521794. · 2.71 Impact Factor
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    ABSTRACT: Herbicide resistance is the most widely used transgenic crop trait for broad-spectrum control of weeds. Here we report a novel 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene (Gr5 aroA ) isolated from glyphosate-contaminated soil. The full Gr5 aroA gene was 1,819 bp and contained a 1,341-bp open reading frame encoding a 47-kDa protein. Phylogenetic analysis showed that Gr5aroA is a class I EPSPS even though most such enzymes are naturally sensitive to glyphosate. Interestingly, Gr5aroA protein contained highly conserved PEP and S3P binding residues (Glu-351) and several motifs insensitive to glyphosate. Transgenic Gr5 aroA plants (T 0) grew normally and produced seeds which we treated with a high-glyphosate solution (4× recommended spray). Analysis of the T 1 progenies showed that Gr5 aroA was inherited at a Mendelian 3:1 segregation ratios and that glyphosate tolerance in T 1 plants was unchanged. Our results show the Gr5 aroA gene to be a promising candidate for the development of commercial transgenic crops with high glyphosate tolerance.
    Molecular Breeding 01/2014; 33(1). · 2.28 Impact Factor
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    ABSTRACT: MYB transcription factors are essential for cotton fiber development. We isolated the R2R3-MYB gene GbMYB2 from Gossypium barbadense. RNA in situ hybridization analysis showed that GbMYB2 is mainly expressed in the outer integuments of cotton ovules and in elongating fibers. GbMYB2 expression increased throughout fiber initiation and during the elongation stage. The expression level of GbMYB2 was higher in the Gossypium hirsutum cultivar Xu142 than in the Xu142 (fl) mutant. Overexpression of GbMYB2 in Arabidopsis caused thicker leaf trichomes and longer roots to develop due to the activation of trichome development-related genes such as GL2. These results indicate that GbMYB2 is an R2R3-MYB gene that is involved in fiber development.
    Plant Physiology and Biochemistry 08/2013; 73C:16-22. · 2.35 Impact Factor
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    ABSTRACT: Artemisinin is an effective anti-malarial drug isolated from A. annua, which has an enormous commercialization demand all over the world. However, the low artemisinin content of A. annua greatly limits the commercialization of artemisinin. In this study, we report the results of our experiments, where for the first time we have achieved the overexpression of ADS, CYP71AV1 and CPR genes in A. annua. Eight transgenic A. annua plants were obtained through Agrobacterium tumefaciens-mediated transformation, which was confirmed by PCR. Southern-blot analyses showed that some of the transgenic lines had low copies of the integration transgenes. The results of real time-qPCR showed that the expression levels of ADS, CYP71AV1 and CPR genes were significantly increased, too. The HPLC analyses showed that the artemisinin contents were significantly increased in these transgenic plants. One of the transgenic plants, ACR16, was found to contain 2.4-fold higher (15.1 mg/g DW) artemisinin than the control plants (pCAMBIA2300 transgenic plants). All above results showed that overexpression of ADS, CYP71AV1 and CPR genes in A. annua could promoted the metabolic flux flows toward biosynthesis of artemisinin and effectively increase the level of artemisinin content in transgenic A. annua plants.
    Industrial Crops and Products 08/2013; 49:380–385. · 3.21 Impact Factor
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    ABSTRACT: Epidemiological studies have shown that regular consumption of fruits and vegetables is associated with reduced risk of chronic diseases. Vegetables can provide vitamins, phenolics, flavonoids, minerals and dietary fibers for optimal health benefits. However, some nutrients contained in many fruits and vegetables cannot meet of the complete nutrition need in the human body. Biotechnology has the potential to improve the nutritional value of crops. Considering the high consumption of romaine lettuce in human diet worldwide, the objective of study is to enhance the contents of vitamin C, phenolics and antioxidant activity in lettuce leaves by genetic engineering techniques. The gene expression level, vitamin C content, total phenolics, as well as total and cellular antioxidant activities were analyzed by real-time PCR, HPLC, Folin–Ciocalteu, Hydro-PSC and CAA methods, respectively. The bio-fortification of genetically engineered lettuce increased vitamin C up to 48.94 ± 1.34 mg/100 g FW following the increased over-expression of At GLDH. This is almost a 3.2-fold increase as the content when compared with wild type lettuce (p < 0.05). In addition, phenolic compounds in transgenic lettuce contained 120.4 ± 1.62 mg GA equiv./100 g FW, almost double the phenolic content of the wild type. Total antioxidant activities were 735.4 ± 47.7 μmol vitamin C equiv./100 g FW, cellular antioxidant activities were 7.33 ± 0.86 μmol quercetin equiv./100 g FW (PBS wash) and 18.14 ± 0.68 μmol quercetin equiv./100 g FW (No PBS wash) in transgenic lettuce, respectively, 1.5, 4 and twofold increases when compared with the wild type. This study suggests that bio-fortification by genetic engineering has great potential to improve vitamin C, phenolic contents and antioxidant activity in lettuce.
    Plant Cell Tissue and Organ Culture 08/2013; 114(2). · 2.61 Impact Factor
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    ABSTRACT: Artemisinin is an endoperoxide sesquiterpene lactone isolated from the aerial parts of Artemisia annua L., and is presently the most potent anti-malarial drug. Owing to the low yield of artemisinin from A. annua as well as the widespread application of artemisinin-based combination therapy recommended by the World Health Organization, the global demand for artemisinin is substantially increasing and is therefore rendering artemisinin in short supply. An economical way to increase artemisinin production is to increase the content of artemisinin in A. annua. In this study, three key genes in the artemisinin biosynthesis pathway, encoding farnesyl diphosphate synthase, amorpha-4, 11-diene C-12 oxidase and its redox partner cytochrome P450 reductase, were over-expressed in A. annua through Agrobacterium-mediated transformation. The transgenic lines were confirmed by Southern blotting and the over-expressions of the genes were demonstrated by real-time PCR assays. The HPLC analysis showed that the artemisinin contents in transgenic lines were increased significantly, with the highest one found to be 3.6-fold higher (2.9 mg/g FW) than that of the control. These results demonstrate that multigene engineering is an effective way to enhance artemisinin content in A. annua.
    Plant Biotechnology Reports 07/2013; 7(3). · 1.59 Impact Factor
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    ABSTRACT: Six transcription factors of APETALA2/ethylene-response factor (AP2/ERF) family were cloned and analyzed in Artemisia annua. Real-time quantitative polymerase chain reaction (RT-Q-PCR) showed that AaORA exhibited similar expression patterns to those of amorpha-4,11-diene synthase gene (ADS), cytochrome P450-dependent hydroxylase gene (CYP71AV1) and double bond reductase 2 gene (DBR2) in different tissues of A. annua. AaORA is a trichome-specific transcription factor, which is expressed in both glandular secretory trichomes (GSTs) and nonglandular T-shaped trichomes (TSTs) of A. annua. The result of subcellular localization shows that AaORA is targeted to the nuclei and the cytoplasm. Overexpression and RNA interference (RNAi) of AaORA in A. annua regulated, positively and significantly, the expression levels of ADS, CYP71AV1, DBR2 and AaERF1. The up-regulated or down-regulated expression levels of these genes resulted in a significant increase or decrease in artemisinin and dihydroartemisinic acid. The results demonstrate that AaORA is a positive regulator in the biosynthesis of artemisinin. Overexpression of AaORA in Arabidopsis thaliana increased greatly the transcript levels of the defense marker genes PLANT DEFENSIN1.2 (PDF1.2), HEVEIN-LIKE PROTEIN (HEL) and BASIC CHITINASE (B-CHI). After inoculation with Botrytis cinerea, the phenotypes of AaORA overexpression in A. thaliana and AaORA RNAi in A. annua demonstrate that AaORA is a positive regulator of disease resistance to B. cinerea.
    New Phytologist 03/2013; · 6.37 Impact Factor
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    ABSTRACT: Plants are sessile organisms, and they can not move away under abiotic or biotic stresses. Thus plants have evolved a set of genes that response to adverse environment to modulate gene expression. In this study, we characterized and functionally studied an ERF transcription factor from , , which plays an important role in biotic stress responses. The promoter had been cloned and GUS staining results of promoter-GUS transgenic showed that is expressed ubiquitiously in all organs. Several putative -acting elements such as W-box, TGA-box and Py-rich element, which are involved in defense responsiveness, are present in the promoter. The expression of can be induced vigorously by methyl jasmonate as well as by ethephon and wounding, implying that may activate some of the defense genes via the jasmonic acid and ethylene signaling pathways of . The results of electrophoretic mobility shift assay (EMSA) and yeast one-hybrid experiments showed that was able to bind to the GCC box -acting element and in yeast. Ectopic expression of could enhance the expression levels of the defense marker genes () and (), and increase the resistance to in the 35S:: transgenic Arabidopsis. The down-regulated expression level of evidently reduced the resistance to in . The overall results showed that positively regulated the resistance to in .
    PLoS ONE 02/2013; 8(2):e57657. · 3.53 Impact Factor
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    ABSTRACT: The phytohormone abscisic acid (ABA) plays an important role in plant development and environmental stress response. In this study, we cloned an ABA receptor orthologue, AaPYL9, from Artemisia annua L. AaPYL9 is expressed highly in leaf and flower. AaPYL9 protein can be localized in both nucleus and cytoplasm. Yeast two-hybrid assay shows AaPYL9 can specifically interact with AtABI1 but not with AtABI2, AtHAB1 or AtHAB2. ABA can enhance the interaction between AaPYL9 and AtABI1 while AaPYL9-89 Pro→Ser and AaPYL9-116 His→Ala point mutations abolishes the interaction. BiFC assay shows that AaPYL9 interacts with AtABI1 in nucleus in planta. Transgenic Arabidopsis plants over-expressing AaPYL9 are more sensitive to ABA in the seed germination and primary root growth than wild type. Consistent with this, ABA report genes have higher expression in AaPYL9 overexpressing plants compared to wild type after ABA treatment. Moreover, overexpression of AaPYL9 in A. annua increases not only drought tolerance, but also artemisinin content after ABA treatment, with significant enhancement of the expression of key genes in artemisinin biosynthesis. This study provides a way to develop A. annua with high-yielding artemisinin and high drought resistance.
    PLoS ONE 02/2013; 8(2):e56697. · 3.53 Impact Factor
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    ABSTRACT: Lipase produced by Penicillium expansum is widely used in laundry detergent and leather industry; however, the absence of an efficient transformation technology sets a major obstacle for further enhancement of its lipase productivity through advanced gene engineering. In this work, Agrobacterium tumefaciens-mediated transformation (ATMT) was investigated for P. expansum PE-12 transformation, using hygromycin phosphotransferase (hph) as a selectable marker gene. As a result, we revealed that the frequency of transformation surpassed 100transformants/10(5)condida, most of the integrated T-DNA appeared as a single copy at a random position in chromosomal DNA, and all the transformants showed mitotic stability. Facilitated by this newly established method, for the first time, P. expansum PE-12 was genetically engineered to improve the lipase yield, through a homologous expression vector carrying the endogenous lipase gene (PEL) driven by the strong constitutive promoter of the glyceraldehydes-3-phosphate dehydrogenase gene (gpdA) from Aspergillus nidulans. The highest expression level of the engineered strain reached up to 1700U/mL, nearly 2-fold of the original industrial strain (900U/mL). Our reproducible ATMT system has not only revealed the great potential of homologous expression-directed genetic engineering, which is more efficient and specific compared to traditional mutagenesis, but also provided new possibilities and perspectives for any other practical applications of P. expansum-related genetic engineering in the future.
    Microbiological Research 12/2012; · 1.94 Impact Factor
  • Xinbo Guo, Tong Li, Kexuan Tang, Rui Hai Liu
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    ABSTRACT: Epidemiological studies have shown that regular consumption of fruits and vegetables is associated with reduced risk of chronic diseases. It is recommended to increase consumption of fruits and vegetables to prevent chronic diseases related to free radical-induced oxidative stress. Different varieties of fruits and vegetables provide different vitamins, phenolics, flavonoids, minerals and dietary fibers for optimal health benefits. Mung bean sprouts are one of the major vegetables in human diet. However, the profile of phytochemicals and effect of germination on phytochemical content and antioxidant activity of mung bean sprouts has not been studied. The objective of this study was to determine the effect of germination on phytochemical profiles and antioxidant activity of mung bean sprouts. Germination of mung beans dramatically increased vitamin C contents in mung bean sprout in a time-dependent manner and reached the peak on day 8 of germination up to 285 mg/100 g DW, almost 24 times higher than the initial concentration in mung bean seeds (p<0.05). On fresh weight basis, one serving of mung bean sprouts (about 104 g) provides 21.6 mg of vitamin C, which could meet 36% of Daily Value (DV). In addition, the germination dramatically increased total phenolic compounds and total flavonoids in mung bean sprouts in a time-dependent manner, up to 4.5 and 6.8 times higher than the original concentration of mung bean seeds, respectively. Quercetin-3-O-glucoside content was significantly increased in mung bean sprouts after germination. The total antioxidant activity of mung bean sprouts was increased by 6 times higher than that of mung bean seeds. Therefore, the germination of mung bean sprouts significantly increased phytochemical content, vitamin C content and antioxidant activity.
    Journal of Agricultural and Food Chemistry 10/2012; · 3.11 Impact Factor
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    ABSTRACT: Hepatocellular carcinoma (HCC) is a common clinical primary malignant tumor; however, efficient drugs for the treatment of HCC are still lacking at the present time. To develop a new approach for liver cancer therapy, we designed a chimeric gene (his-HR) encoding a single-chain variable fragment of human HAb25 (hHscFv) fused to a cytotoxic ribonuclease from Rana catesbeiana (RC-RNase) and expressed the corresponding fusion protein in transgenic tobacco (Nicotiana tabacum). Eleven positive transgenic plant lines were identified from 204 regenerated tobacco plants by PCR and Southern blot analysis, and the immunocompetence of the recombinant his-HR protein was confirmed by Western blotting. The expression levels of his-HR protein ranged from 0.75 to 1.99 µg/g in the fresh tobacco leaves. To characterize the bifunction of the expressed his-HR protein in tobacco, binding specificity and cell toxicity to several cell lines were examined by the indirect immunocytochemical streptavidin-biotin complex method and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay. Data indicated that the his-HR protein had stronger specific binding affinity to HepG2 (human liver HCC cell line) than to the other tumor cell lines and normal liver cell line, and the capacity to kill the HCC cell lines SMMC7721 and HepG2 with an half maximal inhibiting concentration of 2.0 and 2.4 nM, respectively. The results suggest that recombinant bifunctional his-HR protein derived from transgenic plants may provide a novel strategy to treat HCC in the future.
    Biotechnology and Applied Biochemistry 09/2012; 59(5):323-9. · 1.35 Impact Factor

Publication Stats

2k Citations
412.51 Total Impact Points

Institutions

  • 2003–2014
    • Shanghai Jiao Tong University
      • • Fudan-SJTU-Nottingham Plant Biotechnology R&D Center
      • • School of Agriculture and Biology
      Shanghai, Shanghai Shi, China
    • Shanghai University
      Shanghai, Shanghai Shi, China
    • Southwest University
      Kenner, Louisiana, United States
  • 1998–2013
    • Fudan University
      • • State Key Laboratory of Genetic Engineering
      • • Institute of Genetics
      Shanghai, Shanghai Shi, China
  • 2011
    • Chinese Academy of Sciences
      Peping, Beijing, China
    • Southwest University in Chongqing
      Pehpei, Chongqing Shi, China
  • 2010
    • Shenyang Medical College
      Feng-t’ien, Liaoning, China
  • 2002–2008
    • Tsinghua University
      • Department of Electronic Engineering
      Beijing, Beijing Shi, China
  • 2007
    • Government of the People's Republic of China
      Peping, Beijing, China
  • 2006
    • Ningbo University
      Ning-po, Zhejiang Sheng, China
  • 1999
    • University of Nottingham
      Nottigham, England, United Kingdom