Isoptericola luteus sp. nov., a novel yellow bacterium isolated from soil.

An aerobic, non-motile, Gram-stain-positive bacterium, designated strain NEAU-Y5T, was isolated from a soil sample collected from Northeast Agricultural University, Heilongjiang province. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-Y5T belonged to the genus and showed high 16S rRNA sequence similarity to Isoptericola variabilis (98.9 %), Isoptericola nanjingensis (98.9 %), Isoptericola cucumis (98.5 %), Isoptericola hypogeus (98.5 %), Isoptericola dokdonensis (98.5 %), Isoptericola jiangsuensis (98.3 %), and Isoptericola halalbus (98.1 %), followed by other members of the genus Isoptericola (<98 %), and phylogenetically clustered with I. dokdonensis and I. jiangsuensis. Strain NEAU-Y5T was found to grow at 4-40 °C (optimum, 28 °C), pH 6.0-12.0 (optimum, pH 7.0), and tolerated 0-6 % NaCl (w/v). The cell-wall peptidoglycan type was l-Lys-d-Asp. The whole-cell hydrolysates contained glucose, galactose, and ribose. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, and glucosamine unknown phospholipid. Major fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. The predominant menaquinone was MK-9(H4). The DNA G+C content was 73.4 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between strain NEAU-Y5T and the type strains of the genus Isoptericola ranged from 18.6 to 23.5 % and from 77.3 to 81.6 %, respectively. Based on morphological, physiological, chemotaxonomic, and phylogenetic data, as well as digital DNA-DNA hybridization and average nucleotide identity values, the novel strain NEAU-Y5T could be differentiated from its closest relatives. Therefore, the strain represents a novel species of the genus Isoptericola, for which the name Isoptericola luteus sp. nov. is proposed. The type strain is NEAU-Y5T (=CCTCC AA 2019087T=DSM 110637T).

Exploring Research on the Construction and Application of Knowledge Graphs for Aircraft Fault Diagnosis.

Fault diagnosis is crucial for repairing aircraft and ensuring their proper functioning. However, with the higher complexity of aircraft, some traditional diagnosis methods that rely on experience are becoming less effective. Therefore, this paper explores the construction and application of an aircraft fault knowledge graph to improve the efficiency of fault diagnosis for maintenance engineers. Firstly, this paper analyzes the knowledge elements required for aircraft fault diagnosis, and defines a schema layer of a fault knowledge graph. Secondly, with deep learning as the main method and heuristic rules as the auxiliary method, fault knowledge is extracted from structured and unstructured fault data, and a fault knowledge graph for a certain type of craft is constructed. Finally, a fault question-answering system based on a fault knowledge graph was developed, which can accurately answer questions from maintenance engineers. The practical implementation of our proposed methodology highlights how knowledge graphs provide an effective means of managing aircraft fault knowledge, ultimately assisting engineers in identifying fault roots accurately and quickly.

Emission Characteristics of NOx and SO2 during the Combustion of Antibiotic Mycelial Residue.

The antibiotic mycelial residue (AMR) generated from cephalosporin C production is a hazardous organic waste, which is usually disposed of by landfilling that causes potential secondary environmental pollution. AMR combustion can be an effective method to treat AMR. In order to develop clean combustion technologies for safe disposal and energy recovery from various AMRs, the emission characteristics of NOx and SO2 from AMR combustion were studied experimentally in this work. It was found that the fuel-N is constituted by 85% protein nitrogen and 15% inorganic nitrogen, and the fuel-S by 78% inorganic sulfur and 22% organic sulfur. Nitrogen oxide emissions mainly occur at the volatile combustion stage when the temperature rises to 400 °C, while the primary sulfur oxide emission appears at the char combustion stage above 400 °C. Increasing the combustion temperature and airflow cause higher NOx emissions. High moisture content in AMR can significantly reduce the NOx emission by lowering the combustion temperature and generating more reducing gases such as CO. For the SO2 emission, the combustion temperature (700 to 900 °C), airflow and AMR water content do not seem to exhibit obvious effects. The presence of CaO significantly inhibits SO2 emission, especially for the SO2 produced during the AMR char combustion because of the good control effect on the direct emission of inorganic SO2. Employing air/fuel staging technologies in combination with in-situ desulfurization by calcium oxide/salts added in the combustor with operation temperatures lower than 900 °C should be a potential technology for the clean disposal of AMRs.

Molecular Cloning and Expression Profile of Class E Genes Related to Sepal Development in Nelumbo nucifera.

The lotus (Nelumbo Adans.) is an important aquatic plant with ornamental, medicinal and edible values and cultural connotations. It has single-, semi-double-, double- and thousand-petalled types of flower shape and is an ideal material for developmental research of flower doubling. The lotus is a basal eudicot species without a morphological difference between the sepals and petals and occupies a critical phylogenetic position in flowering plants. In order to investigate the genetic relationship between the sepals and petals in the lotus, the class E genes which affect sepal formation were focused on and analyzed. Here, SEPALLATA 1(NnSEP1) and its homologous genes AGAMOUS-LIKE MADS-BOXAGL9 (NnAGL9) and MADS-BOX TRANSCRIPTION FACTOR 6-like (NnMADS6-like) of the class E gene family were isolated from the flower buds of the Asian lotus (Nelumbo nucifera Gaertn.). The protein structure, subcellular localization and expression patterns of these three genes were investigated. All three genes were verified to locate in the nucleus and had typical MADS-box characteristics. NnSEP1 and NnMADS6-like were specifically expressed in the sepals, while NnAGL9 was highly expressed in the petals, suggesting that different developmental mechanisms exist in the formation of the sepals and petals in the lotus. The significant functional differences between NnSEP1, NnMADS6-like and NnAGL9 were also confirmed by a yeast two-hybrid assay. These results expand our knowledge on the class E gene family in sepal formation and will benefit fundamental research on the development of floral organs in Nelumbo.

Lattice-Gas-Automaton Modeling of Income Distribution.

A simple and effective lattice-gas-automaton (LGA) economic model is proposed for the income distribution. It consists of four stages: random propagation, economic transaction, income tax, and charity. Two types of discrete models are introduced: two-dimensional four-neighbor model (D2N4) and D2N8. For the former, an agent either remains motionless or travels to one of its four neighboring empty sites randomly. For the latter, the agent may travel to one of its nearest four sites or the four diagonal sites. Afterwards, an economic transaction takes place randomly when two agents are located in the nearest (plus the diagonal) neighboring sites for the D2N4 (D2N8). During the exchange, the Matthew effect could be taken into account in the way that the rich own a higher probability of earning money than the poor. Moreover, two kinds of income tax models are incorporated. One is the detailed taxable income brackets and rates, and the other is a simplified tax model based on a fitting power function. Meanwhile, charity is considered with the assumption that a richer agent donates a part of his income to charity with a certain probability. Finally, the LGA economic model is validated by using two kinds of benchmarks. One is the income distributions of individual agents and two-earner families in a free market. The other is the shares of total income in the USA and UK, respectively. Besides, impacts of the Matthew effect, income tax and charity upon the redistribution of income are investigated. It is confirmed that the model has the potential to offer valuable references for formulating financial laws and regulations.

Histological and Cytological Characterization of Anther and Appendage Development in Asian Lotus (Nelumbo nucifera Gaertn.).

The lotus (Nelumbo Adans.) is a perennial aquatic plant with important value in horticulture, medicine, food, religion, and culture. It is rich in germplasm and more than 2000 cultivars have been cultivated through hybridization and natural selection. Microsporogenesis and male gametogenesis in the anther are important for hybridization in flowering plants. However, little is known about the cytological events, especially related to the stamen, during the reproduction of the lotus. To better understand the mechanism controlling the male reproductive development of the lotus, we investigated the flower structure of the Asian lotus (N. nucifera). The cytological analysis of anther morphogenesis showed both the common and specialized cytological events as well as the formation of mature pollen grains via meiosis and mitosis during lotus anther development. Intriguingly, an anatomical difference in anther appendage structures was observed between the Asian lotus and the American lotus (N. lutea). To facilitate future study on lotus male reproduction, we categorized pollen development into 11 stages according to the characterized cytological events. This discovery expands our knowledge on the pollen and appendage development of the lotus as well as improving the understanding of the species differentiation of N. nucifera and N. lutea.

Graphene and Au NPs co-mediated enzymatic silver deposition for the ultrasensitive electrochemical detection of cholesterol.

Cholesterol is an essential ingredient in mammals, and serum cholesterol is a major component of atherosclerotic plaques. The level of cholesterol in human serum has become an important index for clinical diagnosis and prevention of cardiovascular disease. In this paper, a simple and ultrasensitive cholesterol biosensor based on graphene oxide (GO) and gold nanoparticles (Au NPs) co-mediated enzymatic silver deposition was designed by immobilizing cholesterol oxidase (CHOD), cholesterol esterase (CHER) and GO onto the surface of Au NPs modified screen-printed carbon electrode (SPE). Under the synergistic effect of CHER, CHOD and GO, the cholesterol was hydrolyzed to generate hydrogen peroxide, which can reduce the silver (Ag) ions in the solution to metallic Ag which deposited on the surface of Au NPs modified SPE. The ultrasensitive detection of cholesterol was achieved by anodic stripping voltammetry measurement of the enzymatically deposited Ag. Under optimal conditions, the anodic stripping peak current of Ag increased with the increasing cholesterol concentration in the range from 0.01µg/mL to 5000µg/mL with a limit of detection of 0.001µg/mL (S/N = 3). In addition, the ultrasensitive cholesterol biosensor exhibited higher specificity, acceptable reproducibility and excellent recoveries for cholesterol detection.

A Fe3O4@Au-basedpseudo-homogeneous electrochemical immunosensor for AFP measurement using AFP antibody-GNPs-HRP as detection probe.

In this study, a Fe3O4@Au-based pseudo-homogeneous electrochemical immunosensor was prepared for detection of alpha fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker. The primary antibody (Ab1) was immobilized on Fe3O4@Au NPs as the capture probe. Horseradish peroxidase (HRP) and secondary antibody (Ab2) were conjugated on gold nanoparticles (GNPs) through electrostatic adsorption to form signal-amplifying labels. In the presence of AFP, a sandwich immunocomplex was formed via specific recognition of antigen-antibody in a Fe3O4@Au-basedpseudo-homogeneousreaction system. After the immunocomplex was captured to the surface of magnetic glassy carbon electrode (MGCE), the labeling HRP catalyzed the decomposition of H2O2, resulting in a substantial current for the quantitative detection of AFP. The amperometric (i-t) method was employed to record the response signal of the immunosensor based on the catalysis of the immobilized HRP toward the reduction of H2O2 with hydroquinone (HQ) as the redox mediator. Under the optimal conditions, the amperometric current response presented a linear relationship with AFP concentration over the range of 20 ng/mL-100 ng/mLwith a correlation coefficient of 0.9940, and the detection limit was 0.64 ng/mL at signal/noise [S/N] = 3. Moreover, the electrochemical immunosensor exhibited higher anti-interference ability, acceptable reproducibility and long-term stability for AFP detection.

Ultrasensitive cholesterol biosensor based on enzymatic silver deposition on gold nanoparticles modified screen-printed carbon electrode.

Cholesterol is one of the essential structural constituents of cell membranes. Determination of cholesterol is of great importance in clinical analysis because the level of cholesterol in serum is an indicator in the diagnosis and prevention of heart diseases. In this work, a simple and ultrasensitive cholesterol biosensor based on enzymatic silver deposition was designed by immobilizing cholesterol oxidase (CHOD) and cholesterol esterase (CHER) onto the surface of gold nanoparticles (Au NPs) modified screen-printed carbon electrode (SPE). By the catalytic action of CHER and CHOD, the cholesterol was hydrolyzed to generate hydrogen peroxide (H2O2) which can reduced the silver (Ag) ions in the solution for the deposition of metallic Ag on the surface of Au NPs modified SPE. The ultrasensitive detection of cholesterol was achieved by anodic stripping voltammetry (ASV) measurement of the enzymatically deposited Ag. The influence of relevant experimental variables was optimized. The anodic stripping peak current of Ag depended linearly on the concentration of cholesterol in the range of 5-5000µg/mL with the regression correlation coefficient of 0.9983. A detection limit of 3.0µg/mL was attained by 3 sigma-rule. In addition, the ultrasensitive cholesterol biosensor exhibited higher specificity, acceptable reproducibility and excellent recoveries for cholesterol detection.

Dynamic expression analysis of early response genes induced by potato virus Y in PVY-resistant Nicotiana tabacum.

KEY MESSAGE: Dynamic transcriptional changes of the host early responses genes were detected in PVY-resistant tobacco varieties infected with Potato virus Y; PVY resistance is a complex process that needs series of stress responses. Potato virus Y (PVY) causes a severe viral disease in cultivated crops, especially in Solanum plants. To understand the molecular basis of plant responses to the PVY stress, suppression subtractive hybridization (SSH) and microarray approaches were combined to identify the potentially important or novel genes that were involved in early stages (12 h, 1, 2, 3, 5, 8 days) of tobacco response to PVY infection. Dynamic changes of the host plant early responses to PVY infection on a transcriptional level were detected. In total, 167 different expressed ESTs were identified. The majority of genes involved in the metabolic process were found to be down-regulated at 12 h and 1 day, and then up-regulated at least one later period. Genes related to signaling and transcriptions were almost up-regulated at 12 h, 1 or 2 days, while stress response genes were almost up-regulated at a later stage. Genes involved in transcription, transport, cell wall, and several stress responses were found to have changed expression during the PVY infection stage, and numbers of these genes have not been previously reported to be associated with tobacco PVY infection. The diversity expression of these genes indicated that PVY resistance is a complex process that needs a series of stress responses. To resist the PVY infection, the tobacco plant has numerous active and silent responses.

Molecular cloning and expression analysis of a Cu/Zn SOD gene (BcCSD1) from Brassica campestris ssp. chinensis.

Superoxide dismutases (SODs) are a family of metalloproteins extensively exists in eukaryote, which plays an essential role in stress-tolerance of higher plants. A full-length cDNA encoding Cu/Zn SOD (BcCSD1) was isolated from young seedlings of non-heading Chinese cabbage (Brassica campestris ssp. chinensis) by rapid amplification of cDNA ends (RACE). Bioinformatics analysis revealed that BcCSD1 belonged to the plant SOD super family and had the closest relationship with SOD from Brassica napus. Tissue expression pattern analysis revealed that the BcCSD1 was constitutively expressed in all the tested tissues, and strongest in leaf, moderate in stem, lowest in root. The expression profiles under different stress treatments such as drought, NaCl, high temperature and ABA were also investigated, and the results revealed that BcCSD1 was a stress-responsive gene, especially to ABA. These results provide useful information for further understanding the role of BcCSD1 resistant to abiotic stress in Brassica campestris in the future.

Transcriptome exploration for further understanding of the tropane alkaloids biosynthesis in Anisodus acutangulus.

Tropane alkaloids (TAs) such as anisodamine, anisodine, hyoscyamine and scopolamine are extensively used in clinical practice as anticholinergic agents. Anisodus acutangulus produces TAs in root tissue, and although several genes involved in scopolamine biosynthesis have been cloned, yet the biosynthetic pathway of TAs remains poorly understood. To further understand TAs biosynthesis mechanism, transcriptome analysis with deep RNA sequencing in A. acutangulus roots was performed in this study; 48 unigenes related to tropane, piperidine and pyridine alkaloid biosynthesis, 145 linked to the distribution of arginine to TAs biosynthesis, and 86 categorized to terpenoid backbone biosynthesis have been identified in pathway enrichment analyses with eukaryotic orthologous groups (KOG) and Kyoto encyclopedia of genes and genomes. Additionally, 82 unigenes annotated as cytochrome P450 family members seemed to be involved in secondary metabolism. Genes encoding littorine mutase/monooxygenase (CYP80F1), diamine oxidase (DAO), alcohol dehydrogenase (ADH) and aromatic amino acid aminotransferase (ArAT) may also play roles in TAs biosynthetic pathways. Furthermore, over 1,000 unigenes were identified as potential transcription factors of WRKY, AP2/ERF, MYB and bHLH families, which would be helpful to understand transcriptional regulation of secondary metabolite biosynthesis. These data enable novel insights into A. acutangulus transcriptome, updating the knowledge of TAs biosynthetic mechanism at molecular level.

Co-overexpression of geraniol-10-hydroxylase and strictosidine synthase improves anti-cancer drug camptothecin accumulation in Ophiorrhiza pumila.

Camptothecin (CPT) belongs to a group of monoterpenoidindole alkaloids (TIAs) and its derivatives such as irinothecan and topothecan have been widely used worldwide for the treatment of cancer, giving rise to rapidly increasing market demands. Genes from Catharanthus roseus encoding strictosidine synthase (STR) and geraniol 10-hydroxylase (G10H), were separately and simultaneously introduced into Ophiorrhiza pumila hairy roots. Overexpression of individual G10H (G lines) significantly improved CPT production with respect to non-transgenic hairy root cultures (NC line) and single STR overexpressing lines (S lines), indicating that G10H plays a more important role in stimulating CPT accumulation than STR in O. pumila. Furthermore, co-overexpression of G10H and STR genes (SG Lines) caused a 56% increase on the yields of CPT compared to NC line and single gene transgenic lines, showed that simultaneous introduction of G10H and STR can produce a synergistic effect on CPT biosynthesis in O. pumila. The MTT assay results indicated that CPT extracted from different lines showed similar anti-tumor activity, suggesting that transgenic O. pumila hairy root lines could be an alternative approach to obtain CPT. To our knowledge, this is the first report on the enhancement of CPT production in O. pumila employing a metabolic engineering strategy.

Preparation of a liposomal delivery system and its in vitro release of rapamycin.

The aim of this study was to prepare a liposomal delivery system for rapamycin and study its in vitro release characteristics. The results may provide a foundation for the further development of a liposomal delivery system for rapamycin and the establishment of a new active treatment method targeted towards the cellular components of atherosclerotic plaques. The ethanol injection method was used to prepare rapamycin-containing liposomes. The formulation was optimized by orthogonal design, and the degree of rapamycin release by the liposomes was measured by the reverse dialysis method. Orthogonal testing showed that the optimum formulation had a phospholipid concentration of 4%, a phospholipid-cholesterol mass ratio of 8:1, a drug-lipid mass ratio of 1:20 and an aqueous phase pH of 7.4. Rapamycin-containing liposomes with an encapsulation efficiency of 82.11±2.13% were prepared, and the in vitro release of rapamycin from the liposomes complied with a first-order kinetic equation. In conclusion, the formulation was optimized, the prepared liposomes had a high rapamycin encapsulation rate and good reproducibility, and their in vitro release had a certain delayed-release effect.

Effects of methyl jasmonate and salicylic acid on tanshinone production and biosynthetic gene expression in transgenic Salvia miltiorrhiza hairy roots.

Tanshinone is a group of active diterpenes, which are widely used in the treatment of cardiovascular disease. In this study, methyl jasmonate (MJ) and salicylic acid (SA) were used to investigate their effects on tanshinone accumulation and biosynthetic gene expression in the hairy roots of geranylgeranyl diphosphate synthase (SmGGPPS) overexpression line (G50) in Salvia miltiorrhiza. High-performance liquid chromatography analysis showed that total tanshinone content in G50 was obviously increased by 3.10-fold (11.33 mg/g) with MJ at 36 H and 1.63 times (5.95 mg/g) after SA treatment for 36 H in comparison with their mimic treatment control. Furthermore, quantitative reverse-transcription PCR analysis showed that the expression of isopentenyl-diphosphate delta-isomerase (SmIPPI), SmGGPPS, copalyl diphosphate synthase (SmCPS), and kaurene synthase-like (SmKSL) increased significantly with MJ treatment. However, the expression of SmIPPI reached the highest level at 144 H, whereas those of SmGGPPS, SmCPS, and SmKSL only increased slightly with SA treatment. The two elicitor treatments suggested that tanshinone accumulation positively correlated to the expression of key genes such as SmGGPPS, SmCPS, and SmKSL. Meanwhile, the study also indicated that it was a feasible strategy to combine elicitor treatment with transgenic technology for the enhancement of tanshinone, which paved the way for further metabolic engineering of tanshinone biosynthesis.

WITHDRAWN: Metabolic engineering and biotechnological approaches for production of bioactive diterpene tanshinones in Salvia miltiorrhiza.

This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Increased accumulation of the cardio-cerebrovascular disease treatment drug tanshinone in Salvia miltiorrhiza hairy roots by the enzymes 3-hydroxy-3-methylglutaryl CoA reductase and 1-deoxy-D-xylulose 5-phosphate reductoisomerase.

Tanshinone is widely used for treatment of cardio-cerebrovascular diseases with increasing demand. Herein, key enzyme genes SmHMGR (3-hydroxy-3-methylglutaryl CoA reductase) and SmDXR (1-deoxy-D-xylulose 5-phosphate reductoisomerase) involved in the tanshinone biosynthetic pathway were introduced into Salvia miltiorrhiza (Sm) hairy roots to enhance tanshinone production. Over-expression of SmHMGR or SmDXR in hairy root lines can significantly enhance the yield of tanshinone. Transgenic hairy root lines co-expressing HMGR and DXR (HD lines) produced evidently higher levels of total tanshinone (TT) compared with the control and single gene transformed lines. The highest tanshinone production was observed in HD42 with the concentration of 3.25 mg g(-1) DW. Furthermore, the transgenic hairy roots showed higher antioxidant activity than control. In addition, transgenic hairy root harboring HMGR and DXR (HD42) exhibited higher tanshinone content after elicitation by yeast extract and/or Ag(+) than before. Tanshinone can be significantly enhanced to 5.858, 6.716, and 4.426 mg g(-1) DW by YE, Ag(+), and YE-Ag(+) treatment compared with non-induced HD42, respectively. The content of cryptotanshinone and dihydrotanshinone was effectively elevated upon elicitor treatments, whereas there was no obvious promotion effect for the other two compounds tanshinone I and tanshinone IIA. Our results provide a useful strategy to improve tanshinone content as well as other natural active products by combination of genetic engineering with elicitors.

Enhancing the production of tropane alkaloids in transgenic Anisodus acutangulus hairy root cultures by over-expressing tropinone reductase I and hyoscyamine-6ß-hydroxylase.

Tropane alkaloids (TA) including hyoscyamine, anisodamine, scopolamine and anisodine, are used medicinally as anticholinergic agents with increasing market demand, so it is very important to improve TA production by metabolic engineering strategy. Here, we report the simultaneous introduction of genes encoding the branch-controlling enzyme tropinone reductase I (TRI, EU424321) and the downstream rate-limiting enzyme hyoscyamine-6ß-hydroxylase (H6H, EF187826) involved in TA biosynthesis into Anisodus acutangulus hairy roots by Agrobacterium-mediated gene transfer technology. Transgenic hairy root lines expressing both TRI and H6H (TH lines) produced significantly higher (P < 0.05) levels of TA compared with the control and single gene transformed lines (T or H lines). The best double gene transformed line (TH53) produced 4.293 mg g(-1) TA, which was about 4.49-fold higher than that of the control lines (0.96 mg g(-1)). As far as it is known, this is the first report on simultaneous introduction of TRI and H6H genes into TA-producing plant by biotechnological approaches. Besides, the content of anisodine was also greatly improved in A. acutangulus by over-expression of AaTRI and AaH6H genes. The average content of anisodine in TH lines was 0.984 mg g(-1) dw, about 18.57-fold of BC lines (0.053 mg g(-1) dw). This is the first time that this phenomenon has been found in TA-producing plants.

Expression of Monstera deliciosa agglutinin gene (mda) in tobacco confers resistance to peach-potato aphids.

The aphid is one of the most serious pests that causes damage to crops worldwide. Lectins from Araceae plant had been proved useful to control the aphid. Herein, the full-length cDNA of Monstera deliciosa agglutinin (mda) gene was cloned and then introduced into tobacco and the influence of the expression of mda in transgenic tobacco against peach-potato aphids (Myzus persicae) was investigated. Among 92 regenerated plants, 59 positive tobacco lines were obtained. Real-time PCR assays and aphid bioassay test revealed that there is a positive correlation between the expression level of mda and the inhibitory effect on peach-potato aphids. The average anti-pests ability of mda transgenic tobacco was 74%, which was higher than that of other reported lectins from Araceae plant. These results indicated that MDA is one of promising insect resistance proteins selected for the control of peach-potato aphids.

Recombinant hHscFv-RC-RNase protein derived from transgenic tobacco acts as a bifunctional molecular complex against hepatocellular carcinoma.

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.