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Sample records for cdna library screening

  1. High-Throughput Plasmid cDNA Library Screening

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    Wan, Kenneth H.; Yu, Charles; George, Reed A.; Carlson, JosephW.; Hoskins, Roger A.; Svirskas, Robert; Stapleton, Mark; Celniker, SusanE.

    2006-05-24

    Libraries of cDNA clones are valuable resources foranalysing the expression, structure, and regulation of genes, as well asfor studying protein functions and interactions. Full-length cDNA clonesprovide information about intron and exon structures, splice junctionsand 5'- and 3'-untranslated regions (UTRs). Open reading frames (ORFs)derived from cDNA clones can be used to generate constructs allowingexpression of native proteins and N- or C-terminally tagged proteins.Thus, obtaining full-length cDNA clones and sequences for most or allgenes in an organism is critical for understanding genome functions.Expressed sequence tag (EST) sequencing samples cDNA libraries at random,which is most useful at the beginning of large-scale screening projects.However, as projects progress towards completion, the probability ofidentifying unique cDNAs via EST sequencing diminishes, resulting in poorrecovery of rare transcripts. We describe an adapted, high-throughputprotocol intended for recovery of specific, full-length clones fromplasmid cDNA libraries in five days.

  2. Optimization of yeast surface-displayed cDNA library screening for low abundance targets.

    Science.gov (United States)

    Kim, Juh-Yung; Kim, Hyung Kyu; Jang, Hye Jeong; Kim, Eun-Kyung; Kim, Moon Kyu

    2015-04-01

    The yeast surface-displayed cDNA library has been used to identify unknown antigens. However, when unknown target antigens show moderate-to-low abundance, some modifications are needed in the screening process. In this study, a directional random-primed cDNA library was used to increase the number of candidates for the unknown antigen. To avoid the loss of target yeast clones that express proteins at a low frequency in the cDNA library, a comprehensive monitoring system based on magnetic-activated cell sorting, fluorescence-activated cell sorting, and immunofluorescence was established, and a small number of target yeast cells was successfully enriched. These results showed that our optimized method has potential application for identifying rare unknown antigens of the human monoclonal antibody.

  3. Design and Screening of M13 Phage Display cDNA Libraries

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    Yuliya Georgieva

    2011-02-01

    Full Text Available The last decade has seen a steady increase in screening of cDNA expression product libraries displayed on the surface of filamentous bacteriophage. At the same time, the range of applications extended from the identification of novel allergens over disease markers to protein-protein interaction studies. However, the generation and selection of cDNA phage display libraries is subjected to intrinsic biological limitations due to their complex nature and heterogeneity, as well as technical difficulties regarding protein presentation on the phage surface. Here, we review the latest developments in this field, discuss a number of strategies and improvements anticipated to overcome these challenges making cDNA and open reading frame (ORF libraries more readily accessible for phage display. Furthermore, future trends combining phage display with next generation sequencing (NGS will be presented.

  4. RAPID SCREENING OF AN ARRAYED cDNA LIBRARY BY IMPROVED PCR-BASED METHOD

    Institute of Scientific and Technical Information of China (English)

    杜光伟; 潘美辉; 袁建刚; 周彦; 强伯勤; 梁植权

    1998-01-01

    Tbe present study reports an improved PCR-based technique that allows quick and effecfive screening of eDNA libraries. First, the eDNA library was arrayed as follows: about 3×106 cDNA clones were multiplied as individual plsques on solid medium in 24-well culture dishes at 1 200 plaque forming units per well.The phage suspension of each well was transferred to an individual micrccentrifuge tube in 72-tube box. Then,box pool, row pools and column pools were set up that respectively represent a 72-tube box,rows and columns within the box. To screen a specific target cDNA,primers specific for novel ESTs obtained in our laboratory were eznployed to conduct PCR in a fiierarchy mode. PCR began with the box pools, resulting in the identification of some positive box pools. Then PCR went down to the row and column pools of the positive box. Tbe intersection of the positive row(s) and column(s) revealed the candidate positive tubes. The specificity of PCR products were meanwhile checked hy restriction enzyme digestion. Finally, hybridization was carried out to get single specific eDNA clones-from the positive tlabes. This PCR-hased technique features high specificity, high efficiency and Les-cost in large-scale cDNA library screening. Our initial implementation of the technique resulted in the isolation of three longer different cDNA clones from a hnman fetal brain eDNA library. Thus this improved technique can serve as an alternative to the time-consuming and laborious conventional hybridization-hased metfiod for screening cDNA library.

  5. Construction of cDNA Library from NPC Tissue and Screening of Antigenic Genes

    Institute of Scientific and Technical Information of China (English)

    Jun Shu; Xiaojuan He; Guancheng Li

    2006-01-01

    To construct cDNA library of nasopharyngeal carcinoma (NPC) and obtain the NPC associated or specific antigens from it, we used a powerful new method to identify the antigens eliciting humoral immune response, which is SEREX (serological identification of antigen by recombinant cDNA expression library). Autologous serum of NPC patient was used to screen the reactive clones in the human NPC tissue cDNA library consisted of 3.64×106 recombinants. The 23 exact positive clones were subcloned to monoclonality and the size of cDNA inserts was identified by PCR. Then the nucleotide sequence of cDNA inserts was determined, and the sequence alignments were performed with BLAST software on GenBank database. They represented 16 different antigens. A detailed sequence analysis showed that 10 of 16 genes were high homologous to genes known in GenBank, such as RPL31,S100 A2, MT2A, etc. However, there were also 6 genes with low homology to genes in GenBank. Furthermore, 3 of 6 genes may be novel genes. The associations of these genes to NPC and the roles that they played in the occurrence and development of NPC should be further revealed.

  6. Requirements in screening cDNA libraries for new genes and solutions offered by SBH technology

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    Drmanac, R.; Drmanac, S.; Labat, I.; Stavropoulos, N.

    1993-12-31

    Under different assumptions about the total number of genes, the number of housekeeping and tissue-specific genes, and the difference in the number of mRNAs per cell for functional and nonfunctional genes, significantly different results can be expected from screening random cDNA clones. We have developed gene expression models as a guide for interpretation of experimental results. For statistical, biological, and technical reasons, the search for 100,000 plus genes and discrimination between nonfunctional, housekeeping, and tissue-specific genes requires the analysis of up to 10 million clones from 20 to 50 tissues. Oligonucleotide hybridization of dense clone blots is an inexpensive and fast way to screen such large clone sets. Our preliminary results on control clones and thousands of cDNA clones from an infant brain library demonstrate the feasibility of the method. We present several models of gene expression and analyze the main factors which can influence the hunt for new genes via the screening of random cDNA libraries. The basic steps in the preparation and use of dense DNA dot arrays are described, and some results that demonstrate the feasibility and efficiency of gene inventorying by oligonucleotide hybridization are presented. Furthermore, partial SBH and single-pass gel sequencing are compared and a gene analysis scheme that combines the two approaches is discussed.

  7. Screening cDNA Libraries Using Partial Probes to Isolate Full-Length cDNAs from Vascular Cells.

    Science.gov (United States)

    Csortos, C; Lazar, V; Garcia, J G

    1999-01-01

    The purpose of screening cDNA libraries is to isolate a particular cDNA clone encoding a mRNA and by implication, a protein, of interest. The screening is based on identification of the desired clone among a large number of recombinant clones within the library selected (1,2). As an example of both the utility and power of library screening, we will relate our own library screening efforts utilized to isolate the nonmuscle high molecular weight myosin light chain kinase isoform from a human umbilical vein endothelial cell cDNA library (3). This unique nonmuscle myosin light chain kinase isoform phosphorylates myosin light chains, thereby playing an essential role in agonist-mediated endothelial cell contraction, paracellular gap formation and increased vascular permeability. We are hopeful that this step-by-step approach will help the reader to understand the discussed methods.

  8. THE CLONING OF HRNT-1 USING A COMBINATION OF cDNA LIBRARY SCREENING WITH BIOTIN-LABELED PROBE AND RAPID AMPLIFICATION OF cDNA ENDS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To clone the human counterpart of rat ZA73, EST cloned from rat tracheal epithelial (RTE) neoplastic transformed cell model induced by (a-particles radiation by using mRNA differential display. Methods: According to the sequence of rat ZA73, a probe was biotin-labeled to screen human cDNA library, and then the gene sequence was extended by RACE (rapid amplification of cDNA ends). Result: Human gene HRNT-1 (GenBank Accession Number: AF223393) is 4.256 kb in length, with an ORF located in the region between 254 and 3013 bp. 5' UTS (untranslated sequences) is 253 bp, 3' UTS is 1243 bp. Conclusion: The combination of cDNA library screening with biotin-labeled probes and RACE is an effective method to clone full-length cDNA, especially for sequences longer than 2 kb.

  9. Rapid and Efficient cDNA Library Screening by Self-Ligation ofInverse PCR Products (SLIP)

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    Hoskins, Roger A.; Stapleton, Mark; George, Reed A.; Yu, Charles; Wan, Kenneth H.; Carlson, Joseph W.; Celniker, Susan E.

    2005-04-22

    The production of comprehensive cDNA clone collections is an important goal of the human and model organism genome projects. cDNA sequences are used to determine the structures of transcripts, including splice junctions, polyadenylation sites, and 5' and 3' untranslated regions (UTRs). cDNA collections are also valuable resources for functional studies of genes and proteins. Expressed Sequence Tag (EST)sequencing is the method of choice for recovering cDNAs representing a majority of the transcripts encoded in a eukaryotic genome. However, EST sequencing samples a library at random, so it realizes diminishing returns as the project progresses. To drive cDNA collections toward completion new methods are needed to recover cDNAs representing specific genes and alternative transcripts, including transcripts with low expression levels. We describe a simple and effective inverse-PCR-based method for screening plasmid libraries to recover intact cDNAs for specific transcripts. We tested the method by screening libraries used in our Drosophila EST projects for 153 transcription factor genes that were not yet represented by full-length cDNAs. We recovered target-specific clones for 104 of the genes: 46 exactly match, 30 improve and 28partially match current gene annotations. Successful application of the screening method depends on cDNA library complexity and quality of the gene models. The approach should be effective for improving cDNA collections for other model organisms and the human. It also provides a simple and rapid method for isolating cDNAs of interest in any system for which plasmid cDNA libraries and complete or partial gene sequences are available.

  10. Screening a Novel Human Breast Cancer-Associated Antigen from a cDNA Expression Library of Breast Cancer

    Institute of Scientific and Technical Information of China (English)

    Shuhua Yang; Lin Zhang; Ruifang Niu; Defa Wang; Yurong Shi; Xiyin Wei; Yi Yang

    2005-01-01

    OBJECTIVE The aim of this research was to clone and express the antigen of the previously prepared monoclonal antibody named M4G3.METHODS Western blots were used to screen a breast cancer cell line that overexpresses the M4G3-associated antigen. A λ zap cDNA expression library of breast cancer cells was constructed and screened using M4G3 as a probe to clone the antigen. The positive clones were subcloned and identified by homologous comparison using BLAST.RESULTS The λ zap cDNA expression library had 1.0x106 independent clones. Fifteen positive clones were isolated following 3 rounds of immunoscreening and identified as being from Mycoplasma pulmonis.CONCLUSION The specific antigen that matched the monoclonal M4G3 antibody is an unknown protein of M. pulmonis. This work is helpful for the further study of the association of M. pulmonis infection with breast cancer.

  11. Screening for plant transporter function by expressing a normalized Arabidopsis full-length cDNA library in Xenopus oocytes

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    Halkier Barbara A

    2006-10-01

    Full Text Available Abstract Background We have developed a functional genomics approach based on expression cloning in Xenopus oocytes to identify plant transporter function. We utilized the full-length cDNA databases to generate a normalized library consisting of 239 full-length Arabidopsis thaliana transporter cDNAs. The genes were arranged into a 96-well format and optimized for expression in Xenopus oocytes by cloning each coding sequence into a Xenopus expression vector. Results Injection of 96 in vitro transcribed cRNAs from the library in pools of columns and rows into oocytes and subsequent screening for glucose uptake activity identified three glucose transporters. One of these, AtSTP13, had not previously been experimentally characterized. Conclusion Expression of the library in Xenopus oocytes, combined with uptake assays, has great potential in assignment of plant transporter function and for identifying membrane transporters for the many plant metabolites where a transporter has not yet been identified.

  12. Lung fibrosis: drug screening and disease biomarker identification with a lung slice culture model and subtracted cDNA Library.

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    Guo, Tong; Lok, Ka Yee; Yu, Changhe; Li, Zhuo

    2014-09-01

    Pulmonary fibrosis is a progressive and irreversible disorder with no appropriate cure. A practical and effective experimental model that recapitulates the disease will greatly benefit the research community and, ultimately, patients. In this study, we tested the lung slice culture (LSC) system for its potential use in drug screening and disease biomarker identification. Fibrosis was induced by treating rat lung slices with 1ng/ml TGF-β1 and 2.5μM CdCl2, quantified by measuring the content of hydroxyproline, and confirmed by detecting the expression of collagen type III alpha 1 (Col3α1) and connective tissue growth factor (CTGF) genes. The anti-fibrotic effects of pirfenidone, spironolactone and eplerenone were assessed by their capability to reduce hydroxyproline content. A subtractive hybridisation technique was used to create two cDNA libraries (subtracted and unsubtracted) from lung slices. The housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was employed to assess the subtraction efficiency of the subtracted cDNA library. Clones from the two libraries were sequenced and the genes were identified by performing a BLAST search on the NCBI GenBank database. Furthermore, the relevance of the genes to fibrosis formation was verified. The results presented here show that fibrosis was effectively induced in cultured lung slices, which exhibited significantly elevated levels of hydroxyproline and Col3α1/CTGF gene expression. Several inhibitors have demonstrated their anti-fibrotic effects by significantly reducing hydroxyproline content. The subtracted cDNA library, which was enriched for differentially expressed genes, was used to successfully identify genes associated with fibrosis. Collectively, the results indicate that our LSC system is an effective model for the screening of drug candidates and for disease biomarker identification.

  13. cDNA Library Screening Identifies Protein Interactors Potentially Involved in Non-telomeric Roles of Arabidopsis Telomerase

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    Ladislav eDokládal

    2015-11-01

    Full Text Available Telomerase-reverse transcriptase (TERT plays an essential catalytic role in maintaining telomeres. However, in animal systems telomerase plays additional non-telomeric functional roles. We previously screened an Arabidopsis cDNA library for proteins that interact with the C-terminal extension (CTE TERT domain and identified a nuclear-localized protein that contains a RNA recognition motif (RRM. This RRM-protein forms homodimers in both plants and yeast. Mutation of the gene encoding the RRM-protein had no detectable effect on plant growth and development, nor did it affect telomerase activity or telomere length in vivo, suggesting a non-telomeric role for TERT/RRM-protein complexes. The gene encoding the RRM-protein is highly expressed in leaf and reproductive tissues. We further screened an Arabidopsis cDNA library for proteins that interact with the RRM-protein and identified five interactors. These proteins are involved in numerous non-telomere-associated cellular activities. In plants, the RRM-protein, both alone and in a complex with its interactors, localizes to nuclear speckles. Transcriptional analyses in wild-type and rrm mutant plants, as well as transcriptional co-analyses, suggest that TERT, the RRM-protein, and the RRM-protein interactors may play important roles in non-telomeric cellular functions.

  14. cDNA Library Screening Identifies Protein Interactors Potentially Involved in Non-Telomeric Roles of Arabidopsis Telomerase.

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    Dokládal, Ladislav; Honys, David; Rana, Rajiv; Lee, Lan-Ying; Gelvin, Stanton B; Sýkorová, Eva

    2015-01-01

    Telomerase-reverse transcriptase (TERT) plays an essential catalytic role in maintaining telomeres. However, in animal systems telomerase plays additional non-telomeric functional roles. We previously screened an Arabidopsis cDNA library for proteins that interact with the C-terminal extension (CTE) TERT domain and identified a nuclear-localized protein that contains an RNA recognition motif (RRM). This RRM-protein forms homodimers in both plants and yeast. Mutation of the gene encoding the RRM-protein had no detectable effect on plant growth and development, nor did it affect telomerase activity or telomere length in vivo, suggesting a non-telomeric role for TERT/RRM-protein complexes. The gene encoding the RRM-protein is highly expressed in leaf and reproductive tissues. We further screened an Arabidopsis cDNA library for proteins that interact with the RRM-protein and identified five interactors. These proteins are involved in numerous non-telomere-associated cellular activities. In plants, the RRM-protein, both alone and in a complex with its interactors, localizes to nuclear speckles. Transcriptional analyses in wild-type and rrm mutant plants, as well as transcriptional co-analyses, suggest that TERT, the RRM-protein, and the RRM-protein interactors may play important roles in non-telomeric cellular functions.

  15. Systematic mining of salt-tolerant genes in halophyte-Zoysia matrella through cDNA expression library screening.

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    Chen, Yu; Zong, Junqin; Tan, Zhiqun; Li, Lanlan; Hu, Baoyun; Chen, Chuanming; Chen, Jingbo; Liu, Jianxiu

    2015-04-01

    Though a large number of salt-tolerant genes were identified from Glycophyte in previous study, genes involved in salt-tolerance of halophyte were scarcely studied. In this report, an important halophyte turfgrass, Zoysia matrella, was used for systematic excavation of salt-tolerant genes using full-length cDNA expression library in yeast. Adopting the Gateway-compatible vector system, a high quality entry library was constructed, containing 3 × 10(6) clones with an average inserted fragments length of 1.64 kb representing a 100% full-length rate. The yeast expression library was screened in a salt-sensitive yeast mutant. The screening yielded dozens of salt-tolerant clones harboring 16 candidate salt-tolerant genes. Under salt-stress condition, these 16 genes exhibited different transcription levels. According to the results, we concluded that the salt-tolerance of Z. matrella might result from known genes involved in ion regulation, osmotic adjustment, as well as unknown pathway associated with protein folding and modification, RNA metabolism, and mitochondrial membrane translocase, etc. In addition, these results shall provide new insight for the future researches with respect to salt-tolerance.

  16. The tetramethylammonium chloride method for screening of cDNA libraries using highly degenerate oligonucleotides obtained by backtranslation of amino-acid sequences

    DEFF Research Database (Denmark)

    Honoré, B; Madsen, Peder; Leffers, H

    1993-01-01

    We describe a method for screening of cDNA libraries with highly degenerate oligonucleotides using tetramethylammonium chloride (TMAC). This method is a convenient alternative to using probes generated by the polymerase chain reaction (PCR), especially when these cannot easily be made. Nylon filt...

  17. Mouse protein arrays from a TH1 cell cDNA library for antibody screening and serum profiling

    OpenAIRE

    2005-01-01

    The mouse is the premier genetic model organism for the study of disease and development. We describe the establishment of a mouse T helper cell type 1 (TH1) protein expression library that provides direct access to thousands of recombinant mouse proteins, in particular those associated with immune responses. The advantage of a system based on the combination of large cDNA expression libraries with microarray technology is the direct connection of the DNA sequence information from a particula...

  18. Identification of midgut microvillar proteins from Tenebrio molitor and Spodoptera frugiperda by cDNA library screenings with antibodies.

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    Ferreira, A H P; Cristofoletti, P T; Lorenzini, D M; Guerra, L O; Paiva, P B; Briones, M R S; Terra, W R; Ferreira, C

    2007-11-01

    The objective of this study was to identify midgut microvillar proteins in insects appearing earlier (Coleoptera) and later (Lepidoptera) in evolution. For this, cytoskeleton-free midgut microvillar membrane from Spodoptera frugiperda (Lepidoptera) and Tenebrio molitor (Coleoptera) were used to raise antibodies. These were used for screening midgut cDNA expression libraries. Positive clones were sequenced, assembled and searched for similarities with gene/protein databases. The predicted midgut microvillar proteins from T. molitor were: cockroach allergens (unknown function), peritrophins (peritrophic membrane proteins), digestive enzymes (aminopeptidase, alpha-mannosidase) and unknown proteins. Predicted S. frugiperda midgut proteins may be grouped into six classes: (a) proteins involved in protection of midgut (thioredoxin peroxidase, aldehyde dehydrogenase, serpin and juvenile hormone epoxide hydrolase); (b) digestive enzymes (astacin, transporter-like amylase, aminopeptidase, and carboxypeptidase); (c) peritrophins; (d) proteins associated with microapocrine secretion (gelsolin, annexin); (e) membrane-tightly bound-cytoskeleton proteins (fimbrin, calmodulin) and (f) unidentified proteins. The novel approach is compared with others and microvillar function is discussed in the light of the predicted proteins.

  19. Construction of human liver cancer vascular endothelium cDNA expression library and screening of the endothelium-associated antigen genes

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    Xing Zhong; Yu-Liang Ran; Jin-Ning Lou; Dong Hu; Long Yu; Yu-Shan Zhang; Zhuan Zhou; Zhi-Hua Yang

    2004-01-01

    AIM: To gain tumor endothelium associated antigen genes from human liver cancer vascular endothelial cells (HLCVECs)cDNA expression library, so as to find some new possible targets for the diagnosis and therapy of liver tumor.METHODS: HLCVECs were isolated and purified from a fresh hepatocellular carcinoma tissue sample, and were cultured and proliferated in vitro. A cDNA expression library was constructed with the mRNA extracted from HLCVECs.Anti-sera were prepared from immunized BALB/c mice through subcutaneous injection with high dose of fixed HLCVECs, and were then tested for their specificity against HLCVECs and angiogenic effectsin vitro, such as inhibiting proliferation and inducing apoptosis of tumor endothelial cells, using immunocytochemistry, immunofiuorescence,cell cycle analysis and MTT assays, etc. The identified xenogeneic sera from immunized mice were employed to screen the library of HLCVECs by modified serological analyses of recombinant cDNA expression libraries (SEREX).The positive clones were sequenced and analyzed by bioinformatics.RESULTS: The primary cDNA library consisted of 2x106recombinants. Thirty-six positive clones were obtained from6×10s independent clones by immunoscreening. Bio-informatics analysis of cDNA sequences indicated that 36 positive clones represented 18 different genes. Among them, 3 were new genes previously unreported, 2 of which were hypothetical genes. The other L5 were already known ones. Series analysis of gene expression (SAGE) database showed that ERP70,GRP58, GAPDH, SSB, S100A6, BMP-6, DVS27, HSP70 and NAC alpha in these genes were associated with endothelium and angiogenesis, but their effects on HLCVECs were still unclear. GAPDH, S100A6, BMP-6 and hsp70 were identified by SEREX in other tumor cDNA expression libraries.CONCLUSION: By screening of HLCVECs cDNA expression library using sera from immunized mice with HLCVECs,the functional genes associated with tumor endothelium or angiogenesis were identified. The

  20. Improved production of fatty acids by Saccharomyces cerevisiae through screening a cDNA library from the oleaginous yeast Yarrowia lipolytica

    DEFF Research Database (Denmark)

    Shi, Shuobo; Ji, Haichuan; Siewers, Verena;

    2016-01-01

    for screening a cDNA library from the oleaginous yeast Yarrowia lipolytica for identification of genes/enzymes that were able to enhance free FA accumulation in Saccharomyces cerevisiae. Several novel enzymes resulting in increasing FA accumulation were discovered. These targets include a GPI anchor protein...... method for high-throughput evaluation of the content of free FAs, but also give new insight into how enzymes from Y. lipolytica may increase the production of fatty acids in S. cerevisiae....

  1. A functional yeast survival screen of tumor-derived cDNA libraries designed to identify anti-apoptotic mammalian oncogenes.

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    Moritz Eißmann

    Full Text Available Yeast cells can be killed upon expression of pro-apoptotic mammalian proteins. We have established a functional yeast survival screen that was used to isolate novel human anti-apoptotic genes overexpressed in treatment-resistant tumors. The screening of three different cDNA libraries prepared from metastatic melanoma, glioblastomas and leukemic blasts allowed for the identification of many yeast cell death-repressing cDNAs, including 28% of genes that are already known to inhibit apoptosis, 35% of genes upregulated in at least one tumor entity and 16% of genes described as both anti-apoptotic in function and upregulated in tumors. These results confirm the great potential of this screening tool to identify novel anti-apoptotic and tumor-relevant molecules. Three of the isolated candidate genes were further analyzed regarding their anti-apoptotic function in cell culture and their potential as a therapeutic target for molecular therapy. PAICS, an enzyme required for de novo purine biosynthesis, the long non-coding RNA MALAT1 and the MAST2 kinase are overexpressed in certain tumor entities and capable of suppressing apoptosis in human cells. Using a subcutaneous xenograft mouse model, we also demonstrated that glioblastoma tumor growth requires MAST2 expression. An additional advantage of the yeast survival screen is its universal applicability. By using various inducible pro-apoptotic killer proteins and screening the appropriate cDNA library prepared from normal or pathologic tissue of interest, the survival screen can be used to identify apoptosis inhibitors in many different systems.

  2. Construction and Screening of an Expression cDNA Library from the Triactinomyxon Spores of Myxobolus cerebralis, the causative agent of Salmonid Whirling Diseases

    OpenAIRE

    Soliman, Hatem Mohamed Touhan

    2005-01-01

    The ZAP Express cDNA library was constructed using mRNA extracted from the triactinomyxon spores. First-strand cDNA was synthesized using Moloney Murine leukaemia virus reverse transcriptase. Following second-strand cDNA synthesis, the double-stranded cDNA was digested with Xho I restriction enzyme, cDNA fragments less than 400bp were removed and the remaining cDNA was ligated with the lambda ZAP Express vector. The recombinants were packaged in vitro using Gigapack III gold packaging extract...

  3. Searching for cellular partners of hantaviral nonstructural protein NSs: Y2H screening of mouse cDNA library and analysis of cellular interactome.

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    Tuomas Rönnberg

    Full Text Available Hantaviruses (Bunyaviridae are negative-strand RNA viruses with a tripartite genome. The small (S segment encodes the nucleocapsid protein and, in some hantaviruses, also the nonstructural protein (NSs. The aim of this study was to find potential cellular partners for the hantaviral NSs protein. Toward this aim, yeast two-hybrid (Y2H screening of mouse cDNA library was performed followed by a search for potential NSs protein counterparts via analyzing a cellular interactome. The resulting interaction network was shown to form logical, clustered structures. Furthermore, several potential binding partners for the NSs protein, for instance ACBD3, were identified and, to prove the principle, interaction between NSs and ACBD3 proteins was demonstrated biochemically.

  4. Searching for cellular partners of hantaviral nonstructural protein NSs: Y2H screening of mouse cDNA library and analysis of cellular interactome.

    Science.gov (United States)

    Rönnberg, Tuomas; Jääskeläinen, Kirsi; Blot, Guillaume; Parviainen, Ville; Vaheri, Antti; Renkonen, Risto; Bouloy, Michele; Plyusnin, Alexander

    2012-01-01

    Hantaviruses (Bunyaviridae) are negative-strand RNA viruses with a tripartite genome. The small (S) segment encodes the nucleocapsid protein and, in some hantaviruses, also the nonstructural protein (NSs). The aim of this study was to find potential cellular partners for the hantaviral NSs protein. Toward this aim, yeast two-hybrid (Y2H) screening of mouse cDNA library was performed followed by a search for potential NSs protein counterparts via analyzing a cellular interactome. The resulting interaction network was shown to form logical, clustered structures. Furthermore, several potential binding partners for the NSs protein, for instance ACBD3, were identified and, to prove the principle, interaction between NSs and ACBD3 proteins was demonstrated biochemically.

  5. A novel approach to investigation of the pathogenesis of active minimal-change nephrotic syndrome using subtracted cDNA library screening.

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    Sahali, Djillali; Pawlak, André; Valanciuté, Asta; Grimbert, Philippe; Lang, Philippe; Remy, Philippe; Bensman, Albert; Guellaën, Georges

    2002-05-01

    Clinical and experimental observations suggest that minimal-change nephrotic syndrome (MCNS) results from T cell dysfunction, via unknown mechanisms. For the identification of genes that are potentially involved in MCNS, a subtractive cDNA library was constructed from cDNA from T cell-enriched peripheral blood mononuclear cells obtained from the same patient during relapse versus remission ("relapse minus remission"). This library was screened by differential hybridization with forward ("relapse minus remission") and reverse ("remission minus relapse") subtractive cDNAs probes, as well as unsubtracted probes from relapse and remission, and irrelevant nephrotic syndrome (membranous nephropathy). A total of 84 transcripts were isolated, of which 12 matched proteins of unknown function and 30 were unknown clones. Among the 42 known transcripts, at least 18 are closely involved in the T cell receptor-mediated complex signaling cascade, including genes encoding components of the T cell receptor and proteins associated with the cytoskeletal scaffold, as well as transcription factors. In particular, it was demonstrated that the expression levels of Fyb/Slap, L-plastin, and grancalcin were increased during relapse, suggesting that the integration of proximal signaling after T cell engagement involves the preferential recruitment of these cytoskeleton-associated proteins in MCNS. Because very low levels of interleukin-12 receptor beta2 mRNA were detected in relapse samples, the interleukin-12 signaling pathway might be defective, suggesting that, in MCNS, T cell activation evolves toward a T helper 2 phenotype. Therefore, the combination of subtractive cloning and differential screening constitutes an efficient approach to the identification of genes that are likely to be involved in the pathophysiologic processes of MCNS.

  6. Preparation of cDNA libraries from vascular cells.

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    Lieb, M E; Taubman, M B

    1999-01-01

    The vast majority of past and present efforts in the molecular cloning of expressed sequences involve isolation of clones from cDNA libraries constructed in bacteriophage lambda (1,2). As discussed in Chapter 6 , screening these cDNA libraries using labeled probes remains the most straightforward method to isolate full length cDNAs for which some partial sequence information is known. Although the availability of high quality reagents and kits over the past decade has made the process of library construction increasingly straightforward, generation of high-quality libraries is a task that still requires a fair amount of dedicated effort. Because alternative PCR-based cloning strategies have become increasingly popular alternatives to cDNA library screening, it is useful to consider the advantages and disadvantages of each strategy before embarking on a project to construct a cDNA library (Table 1). In our opinion, it is worthwhile to construct a cDNA library when the transcript of interest is not exceedingly rare (i.e., can readily be detected by Northern blot analysis of total RNA), when multiple cDNAs will need to be cloned over a period of time, and in situations where occasional mutations can not be tolerated (for example, if the cDNA is to be expressed in mammalian cells to examine function). In situations where the transcript of interest is expressed at exceedingly low levels, or when only a single cDNA needs to be cloned, a PCR-based strategy should be considered. When the tissue source is precious (such as a unique clinical specimen), successful construction of a phage library provides a resource that can be amplified and used for multiple cloning projects over many years, but runs the risk of consuming the available RNA if the library construction fails. Table 1 Comparison of Relative Advantages of cDNA Cloning from Lambda Phage Libraries by Plaque Hybridization Compared to Newer PCR- Based Strategies Lambda phage cDNA library PCR-based strategy Freedom

  7. Improved production of fatty acids by Saccharomyces cerevisiae through screening a cDNA library from the oleaginous yeast Yarrowia lipolytica.

    Science.gov (United States)

    Shi, Shuobo; Ji, Haichuan; Siewers, Verena; Nielsen, Jens

    2016-02-01

    Biological production of fatty acid (FA)-derived products has gained increasing attention to replace petroleum-based fuels and chemicals. FA biosynthesis is highly regulated, and usually it is challenging to design rational engineering strategies. In addition, the conventional 'one sample at a time' method for lipid determination is time consuming and laborious, and it is difficult to screen large numbers of samples. Here, a method for detecting free FAs in viable cells using Nile red staining was developed for use in large-scale screening. Following optimization of the method, it was used for screening a cDNA library from the oleaginous yeast Yarrowia lipolytica for identification of genes/enzymes that were able to enhance free FA accumulation in Saccharomyces cerevisiae. Several novel enzymes resulting in increasing FA accumulation were discovered. These targets include a GPI anchor protein, malate dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase, FA hydroxylase, farnesyltransferase, anoctamin, dihydrolipoamide dehydrogenase and phosphatidylethanolamine-binding protein. The best enzyme resulted in a 2.5-fold improvement in production of free FAs. Our findings not only provide a novel method for high-throughput evaluation of the content of free FAs, but also give new insight into how enzymes from Y. lipolytica may increase the production of fatty acids in S. cerevisiae.

  8. Screening for Novel Binding Proteins Interacting with Human Papillomavirus Type 18 E6 Oncogene in the Hela cDNA Library by Yeast Two-Hybrid System

    Institute of Scientific and Technical Information of China (English)

    Shuang LI; Ping LIU; Ling XI; Xuefeng JIANG; Jianfeng ZHOU; Shixuan WANG; Li MENG; Yunping LU; Ding Ma

    2008-01-01

    To screen for novel binding proteins interacting with high-risk HPV 18 E6 oncogene, the strain AH109 was transformed with pGBKT7-HPV18 E6 plasmid, and subsequent transference was utilized to screen for interacting proteins with HPV 18 E6 in human Hela cDNA library. HPVl8 E6 mRNA was expressed in yeast and there was no self-activation and toxicity in AH109. Seven proteins that interacted with HPV18 E6, including transmembrane protein 87B, phosphonoformate im- muno-associated protein 5, vimentin, KM-HN-1 protein, dedicator of cytokinesis 7, vaccinia related kinase 2 and a hypothetical protein, were identified. It was suggested that yeast two-hybrid system is an efficient for screening interacting proteins. The high-risk HPV 18 E6 oncogene may interact with the proteins, which may be associated with signal transduction and transeriptional control, epithelial cell invasion and migration, as well as humoral and cellular immune etc. This investigation provides functional clues for further exploration of potential oncogenesis targets for cancer biotherapy.

  9. Identification of three wheat globulin genes by screening a Triticum aestivum BAC genomic library with cDNA from a diabetes-associated globulin

    Directory of Open Access Journals (Sweden)

    MacFarlane Amanda J

    2009-07-01

    Full Text Available Abstract Background Exposure to dietary wheat proteins in genetically susceptible individuals has been associated with increased risk for the development of Type 1 diabetes (T1D. Recently, a wheat protein encoded by cDNA WP5212 has been shown to be antigenic in mice, rats and humans with autoimmune T1D. To investigate the genomic origin of the identified wheat protein cDNA, a hexaploid wheat genomic library from Glenlea cultivar was screened. Results Three unique wheat globulin genes, Glo-3A, Glo3-B and Glo-3C, were identified. We describe the genomic structure of these genes and their expression pattern in wheat seeds. The Glo-3A gene shared 99% identity with the cDNA of WP5212 at the nucleotide and deduced amino acid level, indicating that we have identified the gene(s encoding wheat protein WP5212. Southern analysis revealed the presence of multiple copies of Glo-3-like sequences in all wheat samples, including hexaploid, tetraploid and diploid species wheat seed. Aleurone and embryo tissue specificity of WP5212 gene expression, suggested by promoter region analysis, which demonstrated an absence of endosperm specific cis elements, was confirmed by immunofluorescence microscopy using anti-WP5212 antibodies. Conclusion Taken together, the results indicate that a diverse group of globulins exists in wheat, some of which could be associated with the pathogenesis of T1D in some susceptible individuals. These data expand our knowledge of specific wheat globulins and will enable further elucidation of their role in wheat biology and human health.

  10. THE CLONING OF HRNT-1 USING A COMBINATION OF cDNA LIBRARY SCREENING WITH BIOTIN-LABELED PROBE AND RAPID AMPLIFICATION OF cDNA ENDS

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Kai-tai

    2001-01-01

    [1]Tom S, Andrew PR. Human Molecular Genetics [M]. John Wiley & Sons, Inc. United States of America 1996; 335.[2]Zhao Yong-liang, Jin Cui-zhen, Wu De-chang et al. Neoplastic transformation and cytogenetic changes of rat tracheal epithelial cells induced by a-particles irradiation [J]. Chin Med Sci J 1997; 12:202.[3]Frohman MA. Rapid amplification of complementary DNA ends for generation of full-length complementary DNAs: thermal RACE [J]. Methods Enzymol 1993; 218:340.[4]Frederick A, Roger B. Current Protocols in Molecular Biology [M]. John Wiley & Sons, Inc. United States of America 1998; 2.1.1.[5]Roux KH. Optimization and troubleshooting in PCR [J]. PCR Methods Appl 1995; 4:5158.[6]Sambrook, J, Fritsch EF, Maniatis T. Molecular Cloning: A Laboratory Manual [M]. 2nd Ed. New York: Cold Spring Harbor Laboratory, Cold Spring Harbor, 1989; 54.[7]Zhang Y, Frohman MA. Using rapid amplification of cDNA ends (RACE) to obtain full-length cDNAs [J]. Methods Mol Biol 1997; 69:61.[8]Frohman MA. Rapid amplification of complementary DNA ends for generation of full-length complementary DNAs: thermal RACE [J]. Methods Enzymol 1993; 218:340.[9]Iqbal S, Robinson J, Deere D, et al. Efficiency of the polymerase chain reaction amplification of the uid gene for detection of Escherichia coli in contaminated water [J]. Lett Appl Microbiol 1997; 24:498.[10]Schunck B, Kraft W, Truyen U. A simple touch-down polymerase chain reaction for the detection of canine parvovirus and feline panleukopenia virus in feces [J]. J Virol Methods 1995; 55:427.

  11. Screening of genes of proteins interacting with p7 protein of hepatitis C virus from human liver cDNA library by yeast two-hybrid system

    Institute of Scientific and Technical Information of China (English)

    Yan-Ping Huang; Xue-Song Gao; Dong Ji; Shu-Mei Lin; Yan-Wei Zhong; Qing Shao; Shu-Lin Zhang; Jun Cheng; Lin Wang; Jiang Guo; Yan Liu; Yuan Yang; Li-Ying Zhang; Gui-Qin Bai

    2005-01-01

    AIM: To investigate the biological function of p7 protein and to look for proteins interacting with p7 protein in hepatocytes.METHODS: We constructed p7 protein bait plasmid by doning the gene of p7 protein into pGBKT7, then transformed it into yeast AH109 (a type). The transformed yeast was mated with yeast Y187 (α type) containing liver cDNA library plasmid, pACT2 in 2xYPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-α-gal for selection and screening. After extracting and sequencing of plasmids from blue colonies, we performed sequence analysis by bioinformatics.RESULTS: Fifty colonies were selected and sequenced.Among them, one colony was Homo sapiens signal sequence receptor, seven colonies were Homo sapiens H19, seven colonies were immunoglobulin superfamily containing leucine-rich repeat, three colonies were spermatid peri-nuclear RNA binding proteins, two colonies were membrane-spanning 4-domains, 24 colonies were cancer-associated antigens, four colonies were nucleoporin 214 ku and two colonies were CLL-associated antigens.CONCLUSION: The successful cloning of gene of protein interacting with p7 protein paves a way for the study of the physiological function of p7 protein and its associated protein.

  12. Functional screening of a cDNA library from the desiccation-tolerant plant Selaginella lepidophylla in yeast mutants identifies trehalose biosynthesis genes of plant and microbial origin.

    Science.gov (United States)

    Pampurova, Suzana; Verschooten, Katrien; Avonce, Nelson; Van Dijck, Patrick

    2014-11-01

    Trehalose is a non-reducing disaccharide that accumulates to large quantities in microbial cells, but in plants it is generally present in very low, barely-detectible levels. A notable exception is the desiccation-tolerant plant Selaginella lepidophylla, which accumulates very high levels of trehalose in both the hydrated and dehydrated state. As trehalose is known to protect membranes, proteins, and whole cells against dehydration stress, we have been interested in the characterization of the trehalose biosynthesis enzymes of S. lepidophylla; they could assist in engineering crop plants towards better stress tolerance. We previously isolated and characterized trehalose-6-phosphate synthases from Arabidopsis thaliana (desiccation sensitive) and S. lepidophylla (desiccation tolerant) and found that they had similar enzymatic characteristics. In this paper, we describe the isolation and characterization of trehalose-6-phosphate phosphatase from S. lepidophylla and show that its catalytic activities are also similar to those of its homolog in A. thaliana. Screening of an S. lepidophylla cDNA library using yeast trehalose biosynthesis mutants resulted in the isolation of a large number of trehalose biosynthesis genes that were of microbial rather than plant origin. Thus, we suggest that the high trehalose levels observed in S. lepidophylla are not the product of the plant but that of endophytes, which are known to be present in this plant. Additionally, the high trehalose levels in S. lepidophylla are unlikely to account for its desiccation tolerance, because its drought-stress-sensitive relative, S. moellendorffii, also accumulated high levels of trehalose.

  13. T cell-based functional cDNA library screening identified SEC14-like 1a carboxy-terminal domain as a negative regulator of human immunodeficiency virus replication.

    Science.gov (United States)

    Urano, Emiko; Ichikawa, Reiko; Morikawa, Yuko; Yoshida, Takeshi; Koyanagi, Yoshio; Komano, Jun

    2010-05-26

    Genome-wide screening of host factors that regulate HIV-1 replication has been attempted using numerous experimental approaches. However, there has been limited success using T cell-based cDNA library screening to identify genes that regulate HIV-1 replication. We have established a genetic screening strategy using the human T cell line MT-4 and a replication-competent HIV-1. With this system, we identified the C-terminal domain (CTD) of SEC14-like 1a (SEC14L1a) as a novel inhibitor of HIV-1 replication. Our T cell-based cDNA screening system provides an alternative tool for identifying novel regulators of HIV-1 replication.

  14. Differential screening of mitochondrial cDNA libraries from male-fertile and cytoplasmic male-sterile sugar-beet reveals genome rearrangements at atp6 and atpA loci.

    Science.gov (United States)

    Xue, Y; Collin, S; Davies, D R; Thomas, C M

    1994-04-01

    As part of a strategy to define differences in genome organization and expression between cytoplasmic male-sterile (CMS) and male-fertile (MF) sugar-beet mitochondria, cDNA libraries from both mitochondrial genotypes were constructed. Preliminary screening with ribosomal RNA gene probes identified candidate cDNA clones corresponding to structural genes. In addition, reciprocal hybridization experiments were performed using labelled first-strand cDNA to identify uniquely transcribed sequences. One cDNA clone (pYC700) is unique to CMS mitochondria and is located upstream of the F0F1-ATPase subunit 6 gene (atp6). Another cDNA clone (pYC130), when used as a probe in northern hybridization analysis, revealed novel transcript profiles in CMS sugar-beet mitochondria. Sequence analysis of this cDNA showed strong homology with the F0F1-ATPase subunit alpha (atpA) coding sequences from several higher plants. The atp6 and atpA loci from each genotype were cloned and the genomic organization, DNA sequence and transcription of each locus was studied. Differences in the transcript profiles of each gene are a consequence of genomic rearrangements 5' to the coding sequence.

  15. [Construction and analysis of subtractive cDNA library associated with multidrug resistance of acute leukemia].

    Science.gov (United States)

    Ji, Lei; Zhang, Wang-Gang; Liu, Jie; Liu, Xin-Ping; Yao, Li-Bo

    2004-08-01

    The study was aimed to construct subtractive cDNA library associated with multidrug resistance (MDR) of acute leukemia for screening genes related to MDR in leukemia. The improved PCR-based subtractive hybridization was performed to clone differential genes between HL-60/VCR and HL-60 cell line. The mRNA of HL-60/VCR and HL-60 cell line were isolated. Then the mRNA of HL-60/VCR group was reversely transcribed into cDNA by Cap-Finder method, and the mRNA of HL-60 was reversely transcribed into cDNA by ordinary method to be marked by biotin for the hybridization next with HL-60/VCR cDNA. After hybridizing, filtrating through the sephacryl S-400 column, absorbing by the magnetic beads, and amplifying by PCR method, the fragments were cloned by T-A method and the cDNA library was constructed. Then the quality of cDNA library was identified by dot-blotting hybridization method. The results showed that after constriction, the library demonstrated its good quality. There was a high proportion of large fragments in this library. From small amount of samples a large amount of candidate fragments could be screened rapidly at once by dot-blotting hybridization. It is concluded that a differentially-expressed subtractive cDNA library in MDR of leukemia with high quality and larger fragments can be efficiently constructed by improving subtractive hybridization and selective PCR method.

  16. Construction of cDNA Library from Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Yu Guangjun; Wang Yiqin; Shen Xin

    2003-01-01

    In order to isolate and clone salt-tolerance involved genes of Populus euphratica, we constructed a cDNA library from salt-treated leaves of P. euphratica. In the experiment, double strand cDNA were synthesized by a beads-based method. The syntheses of the first strand and the second strand cDNA, adapter ligation and restriction reaction for releasing cDNA were all conducted on the beads. The double strand cDNA were released from magnetic beads by digestion with NotI, and cDNA fragments smaller than 500 bp and residual adapters were removed through cDNA size fractionation columns. Finally, double strand cDNA were directionally cloned intoλExcell vector. The results show that the primary titer of the cDNA library is 7.46×106 pfu per mL and the packaging efficiency reaches 1.47×107 recombinants per μg DNA. λDNA extracted from two clones of plaque were digested by EcoR I and NotI, both of the clones contained inserts larger than 900 bp. These results show that the cDNA library of salt-treated P. euphratica leaves has been successfully constructed.

  17. Construction of full length cDNA expression library of hepatopancreas of Penaeus monodon

    Institute of Scientific and Technical Information of China (English)

    罗田; 徐洵

    2002-01-01

    --mRNA was isolated from the hepatopancrease of shrimp Penaeus monodon with a PolyATtract System 1000 Kit. By using mRNA as template, double- strand cDNA with EcoR I/Xho I ends was synthesized by using a ZAP Express cDNA Synthesis Kit. The cDNA was inserted into the lambda ZAP Express vector predigested with EcoR I/Xho I, and the recombinant DNA was in vitro packaged into larnbda phage with GigapackⅢ Gold packaging extracts. These recombinant phages were then used to transfect E. coli XLl - Blue MRF', and finally a cDNA expression library was constructed. The library is 7.2 × 105pfu in capacity and its recombination ratio is higher than 99%. The size of the inserted cDNAs was determined by EcoR I/Xho I digestion of 9 phagemids prepared by in vivo excision of plaques selected randomly from amplified cDNA library . The longest inserted cDNA is about 1.6 kb in length. The complete sequence (about 1.2 kb) of actin cDNA was amplified from the library by PCR reveals that this library contains full-length cDNAs of Penaeus mod on hepatopancreas and is available for screening and expression of shrimp genes.

  18. Screening of genes for proteins interacting with the PS1TP5 protein of hepatitis B virus: probing a human leukocyte cDNA library using the yeast two-hybrid system

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-kang; ZHAO Long-feng; CHENG Jun; GUO Jiang; LUN Yong-zhi; HONG Yuan

    2006-01-01

    Background The hepatitis B virus (HBV) genome includes S, C, P and X regions. The S region is divided into four subregions of pre-pre-S, pre-S1, pre-S2 and S. PS1TP5 (human gene 5 transactivated by pre-S1 protein of HBV) is a novel target gene transactivated by the pre-S1 protein that has been screened with a suppression subtractive hybridization technique in our laboratory (GenBank accession: AY427953). In order to investigate the biological function of the PS1TP5 protein, we performed a yeast two-hybrid system 3 to screen proteins from a human leukocyte cDNA library interacting with the PS 1TP5 protein.Methods The reverse transcription polymerase chain reaction (RT-PCR) was performed to amplify the gene of PS1TP5 from the mRNA of HepG2 cells and the gene was then cloned into the pGEM-T vector. After being sequenced and analyzed with Vector NTI 9.1 and NCBI BLAST software, the target gene of PS1TP5 was cut from the pGEM-T vector and cloned into a yeast expression plasmid pGBKT7, then "bait" plasmid pGBKT7-PS 1TP5 was transformed into the yeast strain AH109. The yeast protein was isolated and analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting hybridization.After expression of the pGBKT7-PS1TP5 fusion protein in the AH109 yeast strain was accomplished, a yeast two-hybrid screening was performed by mating AH 109 with Y 187 containing a leukocyte cDNA library plasmid.The mated yeast was plated on quadruple dropout medium and assayed for α-gal activity. The interaction between the PS1TP5 protein and the proteins obtained from positive colonies was further confirmed by repeating the yeast two-hybrid screen. After extracting and sequencing of plasmids from blue colonies we carried out a bioinformatic analysis.Results Forty true positive colonies were selected and sequenced, full length sequences were obtained and we searched for homologous DNA sequences from GenBank. Among the 40 positive colonies, 23 coding genes

  19. Procedure for normalization of cDNA libraries

    Science.gov (United States)

    Bonaldo, Maria DeFatima; Soares, Marcelo Bento

    1997-01-01

    This invention provides a method to normalize a cDNA library constructed in a vector capable of being converted to single-stranded circles and capable of producing complementary nucleic acid molecules to the single-stranded circles comprising: (a) converting the cDNA library in single-stranded circles; (b) generating complementary nucleic acid molecules to the single-stranded circles; (c) hybridizing the single-stranded circles converted in step (a) with complementary nucleic acid molecules of step (b) to produce partial duplexes to an appropriate Cot; (e) separating the unhybridized single-stranded circles from the hybridized single-stranded circles, thereby generating a normalized cDNA library.

  20. Csa-19, a radiation-responsive human gene, identified by an unbiased two-gel cDNA library screening method in human cancer cells

    Science.gov (United States)

    Balcer-Kubiczek, E. K.; Meltzer, S. J.; Han, L. H.; Zhang, X. F.; Shi, Z. M.; Harrison, G. H.; Abraham, J. M.

    1997-01-01

    A novel polymerase chain reaction (PCR)-based method was used to identify candidate genes whose expression is altered in cancer cells by ionizing radiation. Transcriptional induction of randomly selected genes in control versus irradiated human HL60 cells was compared. Among several complementary DNA (cDNA) clones recovered by this approach, one cDNA clone (CL68-5) was downregulated in X-irradiated HL60 cells but unaffected by 12-O-tetradecanoyl phorbol-13-acetate, forskolin, or cyclosporin-A. DNA sequencing of the CL68-5 cDNA revealed 100% nucleotide sequence homology to the reported human Csa-19 gene. Northern blot analysis of RNA from control and irradiated cells revealed the expression of a single 0.7-kilobase (kb) messenger RNA (mRNA) transcript. This 0.7-kb Csa-19 mRNA transcript was also expressed in a variety of human adult and corresponding fetal normal tissues. Moreover, when the effect of X- or fission neutron-irradiation on Csa-19 mRNA was compared in cultured human cells differing in p53 gene status (p53-/- versus p53+/+), downregulation of Csa-19 by X-rays or fission neutrons was similar in p53-wild type and p53-null cell lines. Our results provide the first known example of a radiation-responsive gene in human cancer cells whose expression is not associated with p53, adenylate cyclase or protein kinase C.

  1. A NEW METHOD TO CONSTRUCT A FULL-LENGTH cDNA LIBRARY OF HUMAN NORMAL BLADDER TISSUE

    Institute of Scientific and Technical Information of China (English)

    成瑜; 李旭; 陈葳; 杨玉琮; 赵乐

    2003-01-01

    Objective Using template-switch mechanism at the 5'-end of mRNA technique (SMART) to construct a full-length cDNA library of human normal bladder tissue. Methods The novel procedures used the template-switching activity of powerscript reverse transcriptase to synthesize and anchor first-strand cDNA in one step. Following reverse transcription, 5 cycles of PCR were performed using a modified oligo(dT) primer and an anchor primer to enrich the full-length cDNA population with 1.0 g human normal bladder poly(A)+RNA, then double-strand cDNA was synthesized. After digestion with sfiI and size-fractionation by CHROMA SPIN-400 columns, double-strand cDNA was ligated into λTripIEx2 vector and was packaged. We determined the titer of the primary library and the percentage of recombinant clones and finally amplified the library. Results The titer of the cDNA library constructed was 2.1×106 pfu*mL-1, and the amplified cDNA library was 6×1011 pfu*mL-1, the percentage of recombination clones was 99%. Conclusion Using SMART technique helps us to construct full-length cDNA library with high efficiency and high capacity which lays solid foundation for screening target genes of bladder diseases with probes and antibodies.

  2. A BIOINFORMATIC STRATEGY TO RAPIDLY CHARACTERIZE CDNA LIBRARIES

    Science.gov (United States)

    A Bioinformatic Strategy to Rapidly Characterize cDNA LibrariesG. Charles Ostermeier1, David J. Dix2 and Stephen A. Krawetz1.1Departments of Obstetrics and Gynecology, Center for Molecular Medicine and Genetics, & Institute for Scientific Computing, Wayne State Univer...

  3. Construction and analysis of SSH cDNA library of human vascular endothelial cells related to gastrocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Yong-Bo Liu; Zhao-Xia Wei; Li Li; Hang-Sheng Li; Hui Chen; Xiao-Wen Li

    2003-01-01

    AIM: To construct subtracted cDNA libraries of human vascular endothelial cells (VECs) related to gastrocarcinoma using suppression substractive hybridization (SSH) and to analyze cDNA libraries of gastrocarcinoma and VECs in Cancer Gene Anatomy Project (CGAP) database.METHODS: Human VECs related to gastric adenocarcinoma and corresponding normal tissue were separated by magnetic beads coupled with antibody CD31 (Dynabeads CD31). A few amount of total RNA were synthesized and amplified by SMARTTM PCR cDNA Synthesis Kit. Then, using SSH and T/A cloning techniques, cDNA fragments of differentially expressed genes in human VECs of gastric adenocarcinoma were inserted into JM109 bacteria. One hundred positive bacteria clones were randomly picked and identified by colony PCR method. To analyze cDNA libraries of gastrocarcinoma and VECs in CGAP database, the tools of Library Finder,cDNA xProfiler, Digital GENE Expression Displayer (DGED),and Digital Differential Display (DDD) were used.RESULTS: Forward and reverse subtraction cDNA libraries of human VECs related to gastrocarcinoma were constructed successfully with SSH and T/A cloning techniques. Analysis of CGAP database indicated that no appropriate library of VECs related to carcinoma was constructed.CONCLUSION: Construction of subtraction cDNA libraries of human VECs related to gastrocarcinoma was successful and necessary, which laid a foundation for screening and cloning new and specific genes of VECs related to gastrocardnoma.

  4. Isolation and characterization of sequences homologous to the tobacco clone axi 1 (auxin independent) from a Vicia sativa nodule cDNA library

    NARCIS (Netherlands)

    Yalçin-Mendi, Y.; Çetiner, S.; Bisseling, T.

    2001-01-01

    In this research, partial nucleotide sequences of the axi 1 gene, which is related to auxin perception and transduction, isolated from Vicia sativa using cDNA library screening were investigated. Four V. sativa cDNA clones representing homologous of the tobacco axi 1 (auxin independent) cDNA clone w

  5. Cloning and screening of cDNA of Psilgramma menephorn allergen

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To construct a cDNA expression library of Psilgramma menephorn to screen its major allergen so as to provide the basis for producing recombinant allergen vaccine of Psilgramma menephorn. Methods Total RNA was extracted from the whole body of Psilgramma menephorn with Trizol and mRNA was purified with Oligo (dT) Spin-Column. And dscDNA was synthesized through reverse transcription. After blunting, the cDNA fragments were ligated with EcoRⅠ adapters. Then the cDNAs were digested by XhoⅠ, and the fragments less than 400 bp were removed by using GHROMA SPIN-400 column. The remaining fragments longer than 400 bp were ligated with Uni-ZAP XR vector. The recombinants were packaged in vitro and a small portion of the packaged phage was used to infect E.coli XL1-Blue MRF′ for titration. The recombinants were examined by color selection. The size of cDNA inserts and the diversity of library were analyzed by PCR. The library was screened using SPT positive sera from patients with Psilgramma menephorn allergy repeatedly. Results The cDNA expression library consisting of a 5×105 recombinant bacteriophages was constructed with the recombinant ratio of 67%. The average length of recombinant exogenous inserts was about 1.49 kb. Five positive cDNA clones were obtained. Conclusion The constructed cDNA expression library shows appropriate contents and size of cDNA fragments and the related genes of Psilgramma menephorn major allergens were harbored successfully, which lays the foundation for the positive clone identification and further analysis.

  6. cDNA library information - Dicty_cDB | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available [ Credits ] BLAST Search Image Search Home About Archive Update History Contact us Dicty_cDB cDNA library... information Data detail Data name cDNA library information Description of data conten...d - Data analysis method - Number of data entries 14 entries Data item Description cDNA library name Names o...(Slug phase)(S) 4) culminating stages (Morphogenetic phase)(C) 5) sexually fusion-competent KAX3 cells (Gamete phase) (F) cDNA librar...y construction method How to construct cDNA library 1) C

  7. Cloning and screening of cDNA of Psilgramma menephorn allergen

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To construct a cDNA expression library of Psilgramma menephorn to screen its major allergen so as to provide the basis for producing recombinant allergen vaccine of Psilgramma menephorn. Methods Total RNA was extracted from the whole body of Psilgramma menephorn with Trizol and mRNA was purified with Oligo (dT) Spin-Column. And dscDNA was synthesized through reverse transcription. After blunting, the cDNA fragments were ligated with EcoRⅠ adapters. Then the cDNAs were digested by XhoⅠ, and the fra...

  8. Construction and characterization of a normalized whole-life-cycle cDNA library of rice

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A cDNA library with genomic complete coverage is a powerful tool for functional genomic studies. For studying the functions of rice genes on a large scale, a normalized whole-life-cycle cDNA library is constructed based on the strategy of saturation hybridization with genomic DNA using rice cultivar Minghui 63, an elite restorer line for a number of rice hybrids that are widely cultivated in China. This library consists of cDNA from 15 directionally cloned cDNA libraries constructed with different tissues from 9 developmental stages. For normalization, the denatured plasmids purified from the 15 directionally cloned libraries are mixed and hybridized with saturated genomic DNA labeled with magnetic beads in two complementary systems. Well-matched plasmids are captured from the hybridized genomic DNA and electroporated into competent DH10B E. coli for construction of the normalized whole-life-cycle cDNA library. This library consists of 62000 clones with an average insert length about 1.4 kb. Inverse Northern blotting shows that this cDNA library included many rarely expressed genes and tissue-specific genes. Sequencing of 10750 cDNA clones of this library reveals 6399 unique ESTs (expressed sequence tags), indicating that the non-redundancy of the library is about 59.5%. This library has been used to make cDNA microarrays for functional genomic studies.

  9. Screening of genomic libraries.

    Science.gov (United States)

    Novelli, Valdenice M; Cristofani-Yaly, Mariângela; Bastianel, Marinês; Palmieri, Dario A; Machado, Marcos A

    2013-01-01

    Microsatellites, or simple sequence repeats (SSRs), have proven to be an important molecular marker in plant genetics and breeding research. The main strategies to obtain these markers can be through genomic DNA and from expressed sequence tags (ESTs) from mRNA/cDNA libraries. Genetic studies using microsatellite markers have increased rapidly because they can be highly polymorphic, codominant markers and they show heterozygous conserved sequences. Here, we describe a methodology to obtain microsatellite using the enrichment library of DNA genomic sequences. This method is highly efficient to development microsatellite markers especially in plants that do not have available ESTs or genome databases. This methodology has been used to enrich SSR marker libraries in Citrus spp., an important tool to genotype germplasm, to select zygotic hybrids, and to saturate genetic maps in breeding programs.

  10. [cDNA library construction from panicle meristem of finger millet].

    Science.gov (United States)

    Radchuk, V; Pirko, Ia V; Isaenkov, S V; Emets, A I; Blium, Ia B

    2014-01-01

    The protocol for production of full-size cDNA using SuperScript Full-Length cDNA Library Construction Kit II (Invitrogen) was tested and high quality cDNA library from meristematic tissue of finger millet panicle (Eleusine coracana (L.) Gaertn) was created. The titer of obtained cDNA library comprised 3.01 x 10(5) CFU/ml in avarage. In average the length of cDNA insertion consisted about 1070 base pairs, the effectivity of cDNA fragment insertions--99.5%. The selective sequencing of cDNA clones from created library was performed. The sequences of cDNA clones were identified with usage of BLAST-search. The results of cDNA library analysis and selective sequencing represents prove good functionality and full length character of inserted cDNA clones. Obtained cDNA library from meristematic tissue of finger millet panicle represents good and valuable source for isolation and identification of key genes regulating metabolism and meristematic development and for mining of new molecular markers to conduct out high quality genetic investigations and molecular breeding as well.

  11. Construction of a metastasis-associated gene subtracted cDNA library of human colorectal carcinoma by suppression subtraction hybridization

    Institute of Scientific and Technical Information of China (English)

    Li Liang; Yan-Qing Ding; Xin Li; Guang-Zhi Yang; Jun Xiao; Li-Chun Lu; Jin-Hua Zhang

    2004-01-01

    AIM: To construct a differentially-expressed gene subtracted cDNA library from two colorectal carcinoma (CRC) cell lines with different metastatic phenotypes by suppression subtractive hybridization.METHODS: Two cell lines of human CRC from the same patient were used. SW620 cell line showing highly metastatic potential was regarded as tester in the forward subtractive hybridization, while SW480 cell line with lowly metastatic potential was treated as tester in the reverse hybridization. Suppression subtractive hybridization (SSH)was employed to obtain cDNA fragments of differentially expressed genes for the metastasis of CRC. These fragments were ligated with T vectors, screened through the bluewhite screening system to establish cDNA library.RESULTS: After the blue-white screening, 235 white clones were picked out from the positive-going hybridization and 232 from the reverse. PCR results showed that 200-700 bp inserts were seen in 98% and 91% clones from the forward and reverse hybridizations, respectively.CONCLUSIONS: A subtractive cDNA library of differentially expressed genes specific for metastasis of CRC can be constructed with SSH and T/A cloning techniques.

  12. [Development of new SSR markers from EST of SSH cDNA libraries on rose fragrance].

    Science.gov (United States)

    Yan, Hui-Jun; Zhang, Hao; Xie, Ji-Rong; Li, Shu-Fa; Jian, Hong-Ying; Qiu, Xian-Qin; Wang, Qi-Gang; Wang, Ji-Hua; Tang, Kai-Xue

    2009-09-01

    The new SSR markers of rose related fragrance were developed based on the SSH cDNA libraries of rose floral scent mutant. In this study, 10 EST-SSRs (2.6%) from 391 ESTs in the libraries were identified. Six EST-SSRs primers were designed to sequence flanking SSRs. The primer pairs designed were screened on the wild-type Jinyindao, which has flowers full of pleasant scent, and the mutant-type Wangriqinghuai without perceivable floral scent. Five primer pairs were amplified effectively in Jinyindao and Wangriqinghuai, and 3 were polymorphic between Jinyindao and Wangriqinghuai. Eighteen rose cultivars including fragrant roses and nonfragrant roses were identified by the five prime pairs. These results proved that EST-SSR markers are effective markers to identify the polymorphism of the rose.

  13. Construction and analysis of SSH cDNA library of human vascular endothelial cells related to gastrocarcinoma

    OpenAIRE

    2003-01-01

    AIM: To construct subtracted cDNA libraries of human vascular endothelial cells (VECs) related to gastrocarcinoma using suppression substractive hybridization (SSH) and to analyze cDNA libraries of gastrocarcinoma and VECs in Cancer Gene Anatomy Project (CGAP) database.

  14. A method for generating subtractive cDNA libraries retaining clones containing repetitive elements.

    OpenAIRE

    1997-01-01

    Here we describe a two-stepped photobiotin-based procedure to enrich a target (canine retinal) cDNA library for tissue specific clones without removing those containing repetitive ( SINE ) elements, despite the presence of these elements in the driver population. In a first hybridization excess SINE elements were hybridized to a driver (canine cerebellar) cDNA. In a second hybridization target cDNA was added to this reaction. The resulting cDNA library was enriched for retinal specific clones...

  15. CDNA library from the Latex of Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Wilaiwan Chotigeat

    2010-12-01

    Full Text Available Latex from Hevea brasiliensis contains 30-50% (w/w of natural rubber (cis-1,4-polyisoprene, the important rawmaterial for many rubber industries. We have constructed a cDNA library from the latex of H. brasiliensis to investigate theexpressed genes and molecular events in the latex. We analyzed 412 expressed sequence tags (ESTs. More than 90% of theEST clones showed homology to previously described sequences in public databases. Functional classification of the ESTsshowed that the largest category were proteins of unknown function (30.1%, 11.4% of ESTs encoded for rubber synthesisrelatedproteins (RS and 8.5% for defense or stress related proteins (DS. Those with no significant homology to knownsequences (NSH accounted for 8.7%, primary metabolism (PM and gene expression and RNA metabolism were 7.8% and6.6%, respectively. Other categories included, protein synthesis-related proteins (6.6%, chromatin and DNA metabolism(CDM 3.9%, energy metabolism (EM 3.4%, cellular transport (CT 3.2%, cell structure (CS 3.2%, signal transduction (ST2.2%, secondary metabolism (SM 1.7%, protein fate (PF 2.2%, and reproductive proteins (RP 0.7%.

  16. Construction of the subtractive cDNA library of injured adult and fetal rabbit skins

    Institute of Scientific and Technical Information of China (English)

    张波; 刘大维; 王正国; 朱佩芳; 周继红; 蒋建新

    2004-01-01

    Objective: Early gestational mammalian fetuses possess the amazing ability to heal cutaneous wounds in a scarless fashion. Over the past years, scientists have been working to decipher the mechanisms underlying this regenerative repair. The remarkable phenotypic differences between fetal and adult healings behoves us to learn their characteristics in genetics, which represents potentially important mechanisms involved in wound repair observed in fetal versus adult tissues. In this sense, it is reasonable to construct subtractive cDNA library for future research.Methods: Middle laparotomy and hysterotomy were performed on pregnant rabbits at 20-day gestation to expose the fetal back, and a longitudinal incision through the skin was made on the back of the fetus. The traumatized fetal skin was harvested 12 hours post-operation, the fetus control and traumatized adult skin specimens were taken at the same time. dscDNA was synthesized from total RNA of skin samples with SMART technology. Taking one of the three samples as Tester respectively and the other two as Drivers, we obtained 1 forward and 2 reverse hybridization products. After being amplified with selective polymerase chain reaction, the products were inserted into a vector, and then transferred into E.coli HB101. The colonies were screened afterwards. Results: The wounded fetuses were alive for a long time even after birth. Every determinant step, such as RNA isolation, cDNA synthesis, Rsa I digestion, adaptor ligation and hybridization, was well-operated. Subtractive efficiency identification demonstrated that the suppression subtractive hybridization (SSH) was successful. Insertion into vector and transferring to E.coli were satisfactory. Conclusions: Instead of classic SSH, an improved SSH with 2 Drivers was applied for the experiment. Results confirmed that the improved program was reasonable and correct in both theory and practice. The subtractive cDNA library we have obtained is going to be used for

  17. 酵母双杂交筛选胎肾上腺cDNA文库中HNP-1结合蛋白%SCREENING THE GENE SEQUENCES OF THE INTERACTION PROTEINS OF HNP-1 FROM HUMAN FETAL ADRENAL CDNA LIBRARY BY YEAST TWO HYBRID SYSTEM

    Institute of Scientific and Technical Information of China (English)

    杜润滋; 邓璐霞; 黄宁; 罗朝志

    2011-01-01

    [Objective] To screen proteins binding with α-defensin (HNP-1) mature peptide from placenta cDNA libraty by yeast two hybrid technique. [Methods] The cDNA fragment encoding HNP-1 mature peptide was amplified by polymera-sechain reaction (PCR) and constructed into pGBK-T7 vector as the bait plasmid in yeast two hybrid system 3. Subsequently , the RNA from fetal adrenal gland was obtained and then transformed into cDNA library using SMART technology. The fetal adrenal cDNA library was screened with pGBKT7-HNP-1 as bait plasmid by yeast-two hybrid system Matchmaker Lexa. Finally, the positive clone was obtained by PCR and then identified by sequence. Then the interaction between them was determined by GST pull down in vitro and coimmunoprecipitates experiments in vivo. [Results] Bait and cDNA library have been constructed successfully and transformed into yeast. Then the interaction protein was found-melanocortin 2 receptor (ACTHR), CCAAT-enhancer-binding proteins (C/EBP), Tramembrane trafficking protein (TMP21), low density lipoprotein receptor-related protein 6 (LRP6). Therefore, melanocortin 2 receptor (ACTH-R) was determined into the major subjects. And bands which can demonstrate the relationship between HNP-1 and ACTH-R was obtained in GST pull down and coimmunoprecipitates experiments. [Conclusion] ACTH-R can bind to HNP-1 we obtained from fetal adrenal cDNA library and it may play important roles in the function of HNP-1 mature peptide.%[目的]筛选胎肾上腺cDNA文库中与α防御素HNP-1成熟肽具有相互作用的蛋白分子.[方法]通过聚合酶链反应(PCR)成功获得HNP-1成熟肽基因插入酵母表达载体pGBK-T7中构建诱饵质粒,同时提取胎肾上腺RNA,SMART技术制备人胎肾上腺cDNA文库,并采用Matchmaker LexA酵母双杂交系统从胎肾上腺cDNA文库中筛选与HNP-1成熟肽相互作用的蛋白.最后通过PCR筛选获得阳性克隆并测序,而后经回转实验,GST pull down以及免疫共沉淀再次验证

  18. Construction and Characterization of a cDNA Expression Library for the North American Ginseng Root Tissues

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; WANG Kun; BAO Yong-li; WU Yin; MENG Xiang-ying; LI Yu-xin

    2007-01-01

    The root of Panax ginseng plant undergoes a specific developmental process to become a biosynthesis and accumulation tissue for ginsenosides. To identify and analyze genes involved in the biosynthesis of ginsenoside, we constructed and characterized a full-length cDNA library for 6-year-old North American ginseng. The titer of primary cDNA library is 1.2×106 pfu/mL, the titer of amplified library is 2.6×1010 pfu/mL and the rate of recombinant is above 86%. The insert size ranges from 0.3 to 2.0 kb. Sequencing results show that 18 of 58 genes are high homologous to the genes(GBR5, GBR3 and GBR1) known in GenBank, which are involved in biosynthesis of ginsenoside in North American ginseng plant; 16 of 58 genes are novel genes. The full-length cDNA library of North American ginseng root tissues is essential for the cloning of genes known and it is also an initial key for the screening and cloning of new genes.

  19. Construction of a hepatic stellate cells subtracted cDNA library of differentially expressed genes in normal mice and mice with Schistosomiasis japonica

    Institute of Scientific and Technical Information of China (English)

    Zheng Min; Wu Yi-jun; Cai Wei-min; Weng Hong-lei; Liu Rong-hua

    2005-01-01

    To construct a hepatic stellate cells (HSCs) subtracted cDNA library to find differentially expressed genes in normal mice and mice infected with Schistosomajaponicum (S. japonicum). Suppression subtractive hybridization (SSH) was used. The cDNA fragments of normal mouse were compared to those of schistosoma-infected mice to find differentially expressed genes.Then differentially expressed cDNA fragments were directly inserted into T/A cloning vector to set up the subtractive library.Amplification of the library was carried out with transformation of DH5α. The amplified library contained more than 400 positive bacterial clones, which were then hybridized with forward and backward subtracted probes for differential screening. One hundred positive bacterial clones were randomly selected for sequencing and BLAST analysis. Finally, virtual Northern Blot confirmed such differential expression. The subtracted cDNA library of differentially expressed genes of HSCs was constructed successfully,the library is efficient and lays foundation for screening and cloning new and specific genes of schistosomiasis.

  20. Construction of a Plant Transformation-ready Expression cDNA Library for Thellungiella halophila Using Recombination Cloning

    Institute of Scientific and Technical Information of China (English)

    Wan-Song Ni; Zhi-Yong Lei; Xi Chen; David J. Oliver; Cheng-Bin Xiang

    2007-01-01

    Salt cress (Thellungiella halophila), a close relative of the model plant Arabidopsis thaliana L., is an extremophile that is adapted to harsh saline environments. To mine salt-tolerance genes from this species, we constructed an entry cDNA library from the salt cress plant treated with salt-stress by using a modified cDNA synthesis and an improved recombinationassisted cDNA library construction method that is completely free of manipulations involving restriction enzymes and DNA ligase. This cDNA library construction procedure is significantly simplified and the quality of the cDNA library is improved. This entry cDNA library was subsequently shuttled into the destination binary vector pCB406 designed for plant transformation and expression via recombination-assisted cloning. The library is plant transformation ready and is used to transform Arabidopsis on a large scale in order to create a large collection of transgenic lines for functional gene mining.

  1. SEREX技术筛选及鉴定食管癌肿瘤抗原%Human Esophageal Carcinoma Antigens Screened by Serologic Analysis of Recombinant cDNA Expression Libraries (SEREX)

    Institute of Scientific and Technical Information of China (English)

    遇珑; 胡海; 冉宇靓; 彭良平; 李江伟; 杨治华

    2007-01-01

    背景与目的:正常细胞向癌细胞转化过程中,突变的基因或各种异常表达的蛋白可以成为肿瘤抗原诱导机体的免疫反应,因此肿瘤患者的血清中存在着与肿瘤相关的自身抗体.重组cDNA表达文库血清学分析法(serological analysis of recombinant cDNA expression libraries,SEREX)是利用肿瘤患者血清中的自身抗体筛选、鉴定肿瘤抗原的技术.本研究拟采用SEREX的方法寻找食管癌自身抗体的相关肿瘤抗原,鉴定与食管癌发生、发展相关的基因和免疫治疗分子靶点,并为食管癌的诊断提供候选血清标志物.方法:用食管癌组织建立库容量达1.6×106 pfu的cDNA表达文库,SEREX筛选获得21个不同cDNA序列的阳性克隆,进一步使用SADA法分析其中4个抗原在10例食管癌及10例正常人血清中的反应.结果:在Homosapiens desmin(DES)等21个阳性克隆中,4个克隆与已知EST序列明显无同源性,另外17个克隆与已知基因高度同源.Ribosomal protein S4等4个抗原与食管癌患者和正常人血清反应阳性率分别为40%和0%、60%和10%、70%和20%、30%和20%.结论:Ribosomal protein S4等4个抗原普遍参与了食管癌患者的体液免疫反应,与食管癌患者血清的反应阳性率明显高于正常人的血清.本研究发现的21个食管癌抗原可作为食管癌治疗的潜在分子靶点和食管癌诊断新的候选血清学标志物.

  2. Construction and analysis of a subtracted cDNA library of Betula platyphylla female inflorescence

    Institute of Scientific and Technical Information of China (English)

    WEIJi-cheng; YANGChuan-ping; WANGChao; JIANGJing

    2005-01-01

    Female inflorescence of Betula platyphylla was sampled at an interval of each two days to analyze the background of gene expression in floral phase. On the basis of SMART strategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA was from that of the others by RT-PCR which were subsequently used to construct a subtracted cDNA library. The result of the ESTs (expression sequence tags) blastX showed that the genes in the subtracted cDNA library could be mainly clustered into 5 groups related to metabolism, transportation and signal transduction, cell cycle, stress response, and regulation. The relationship between gene expression and development was also discussed.

  3. Virtual screening of virtual libraries.

    Science.gov (United States)

    Green, Darren V S

    2003-01-01

    Virtual screening of virtual libraries (VSVL) is a rapidly changing area of research. Great efforts are being made to produce better algorithms, selection methods and infrastructure. Yet, the number of successful examples in the literature is not impressive, although the quality of work certainly is high. Why is this? One reason is that these methods tend to be applied at the lead generation stage and therefore there is a large lead-time before successful examples appear in the literature. However, any computational chemist would confirm that these methods are successful and there exists a glut of start-up companies specialising in virtual screening. Moreover, the scientific community would not be focussing so much attention on this area if it were not yielding results. Even so, the paucity of literature data is certainly a hindrance to the development of better methods. The VSVL process is unique within the discovery process, in that it is the only method that can screen the > 10(30) genuinely novel molecules out there. Already, some VSVL methods are evaluating 10(13) compounds, a capacity that high throughput screening can only dream of. There is a huge potential advantage for the company that develops efficient and effective methods, for lead generation, lead hopping and optimization of both potency and ADME properties. To do this, it requires more than the software, it requires confidence to exploit the methodology, to commit synthesis on the basis of it, and to build this approach into the medicinal chemistry strategy. It is a fact that these tools remain quite daunting for the majority of scientists working at the bench. The routine use of these methods is not simply a matter of education and training. Integration of these methods into accessible and robust end user software, without dilution of the science, must be a priority. We have reached a coincidence, where several technologies have the required level of maturity predictive computational chemistry

  4. Biological characterization of liver fatty acid binding gene from miniature pig liver cDNA library.

    Science.gov (United States)

    Gao, Y H; Wang, K F; Zhang, S; Fan, Y N; Guan, W J; Ma, Y H

    2015-01-01

    Liver fatty acid binding proteins (L-FABP) are a family of small, highly conserved, cytoplasmic proteins that bind to long-chain fatty acids and other hydrophobic ligands. In this study, a full-length enriched cDNA library was successfully constructed from Wuzhishan miniature pig, and then the L-FABP gene was cloned from this cDNA library and an expression vector (pEGFP-N3-L-FABP) was constructed in vitro. This vector was transfected into hepatocytes to test its function. The results of western blotting analysis demonstrated that the L-FABP gene from our full-length enriched cDNA library regulated downstream genes, including the peroxisome proliferator-activated receptor family in hepatocytes. This study provides a theoretical basis and experimental evidence for the application of L-FABP for the treatment of liver injury.

  5. Construction of a rice immature seeds cDNA library and molecular cloning of oryzacystatin cDNA

    Institute of Scientific and Technical Information of China (English)

    周兆斓; 朱祯; 刘春明; 张海涛; 肖桂芳; 李向辉

    1996-01-01

    Total RNA was extracted from rice immature seeds harvested 2 weeks after flowering; then mRNA was purified. cDNA with NotI and SaiI cohesive ends was synthesized and inserted into λgt22A. After packaged in vitno, the cDNA library was constructed with 1.5×106pfu. A 21-mer oligodeoxynucleotide was synthesized according to the 5’-end conserved coding sequence of oryzacystatin (a thiol proteinase inhibitor) and labeled as a probe. From 2.1 × 104 pfu, 9 positive dones have been isolated, 8 of which contain the entire coding region of oryzacystatin. λOC1 has the longest cDNA insert, which contains an open reading frame of 309 bp coding sequence, 84 bp 5’-end non-coding region and a poly(A) signal AATAAA at the 3’-end followed by 31 Nt of poly(A). The coding sequence is the same compared with oryzacystatin genomic DNA sequence, while there are some obvious differences such as insertion and variation in the non-coding region, especially lots of nonsucoessive insertion in the 3’ region after poly(A) signal.

  6. Construction of cDNA subtractive library between yeast and mycelium phase of Sporothrix schenckii and screening of differently expressed genes about dimorphic transition%申克孢子丝菌菌丝相和酵母相cDNA消减文库的构建及差异表达基因的筛选

    Institute of Scientific and Technical Information of China (English)

    周汛; 杨致邦; 肖异珠

    2011-01-01

    The purpose of this study was to screen the differentially expressed genes about dimorphic transition of Sporothrix schenckii by construction of eDNA subtractive library between yeast and mycelium phase.The eDNA subtractive library between yeast and mycelium phase was constructed by suppression subtractive hybridization(SSH)and bioinformatics analysis was performed to profile the relationship between those differently expressed genes and dimorphic transition.Of 751 and 875 ESTs were obtained in M+Y and Y+M library, separately.After splicing of ESTs, 101 and 249 unigenes were obtained in M +Y and Y+ M libraries.During the construction of cDNA subtractive libraries, the distribution of differently expressed genes varied with dimorphic transition.The over expressed genes with diversity and complexity were divided into structural genes,metabolic enzymes, molecule on cell surface and molecule with indistinct function.Results disclose that construction of cDNA subtractive libraries for the dimorphic transition and bioinformatics analysis for those differently expressed genes lay the foundation for screening the related genes involved in the pathogenesis of Sporothrix schenckii infection.%目的 构建申克孢子丝菌双相cDNA消减文库,筛选与双相转换相关的差异表达基因.方法 运用抑制性消减杂交技术,构建申克孢子丝菌菌丝相(Mycelium,M)和酵母相(Yeast,Y)的正反cDNA消减文库,并对其差异表达的基因进行生物信息学分析.结果 M+Y文库获得751条表达序列标签(Expressed Sequence Tags,ESTs),经拼接后获得101条unigenes;Y+M文库获得875条ESTs,拼接获得249条unigenes.申克孢子丝菌酵母相菌丝相的转换伴随着不同菌相细胞差异基因的高表达,这些高表达的差异基因可分为结构基因类、代谢酶类、细胞表面分子类及功能不明的细胞分子.结论 成功构建了申克孢子丝菌双相转换相关的cDNA消减文库基础上,筛选出部分差异表达基

  7. Characterization of Leukemia-Inducing Genes Using a Proto-Oncogene/Homeobox Gene Retroviral Human cDNA Library in a Mouse In Vivo Model.

    Directory of Open Access Journals (Sweden)

    Su Hwa Jang

    Full Text Available The purpose of this research is to develop a method to screen a large number of potential driver mutations of acute myeloid leukemia (AML using a retroviral cDNA library and murine bone marrow transduction-transplantation system. As a proof-of-concept, murine bone marrow (BM cells were transduced with a retroviral cDNA library encoding well-characterized oncogenes and homeobox genes, and the virus-transduced cells were transplanted into lethally irradiated mice. The proto-oncogenes responsible for leukemia initiation were identified by PCR amplification of cDNA inserts from genomic DNA isolated from leukemic cells. In an initial screen of ten leukemic mice, the MYC proto-oncogene was detected in all the leukemic mice. Of ten leukemic mice, 3 (30% had MYC as the only transgene, and seven mice (70% had additional proto-oncogene inserts. We repeated the same experiment after removing MYC-related genes from the library to characterize additional leukemia-inducing gene combinations. Our second screen using the MYC-deleted proto-oncogene library confirmed MEIS1and the HOX family as cooperating oncogenes in leukemia pathogenesis. The model system we introduced in this study will be valuable in functionally screening novel combinations of genes for leukemogenic potential in vivo, and the system will help in the discovery of new targets for leukemia therapy.

  8. Characterization of Leukemia-Inducing Genes Using a Proto-Oncogene/Homeobox Gene Retroviral Human cDNA Library in a Mouse In Vivo Model.

    Science.gov (United States)

    Jang, Su Hwa; Lee, Sohyun; Chung, Hee Yong

    2015-01-01

    The purpose of this research is to develop a method to screen a large number of potential driver mutations of acute myeloid leukemia (AML) using a retroviral cDNA library and murine bone marrow transduction-transplantation system. As a proof-of-concept, murine bone marrow (BM) cells were transduced with a retroviral cDNA library encoding well-characterized oncogenes and homeobox genes, and the virus-transduced cells were transplanted into lethally irradiated mice. The proto-oncogenes responsible for leukemia initiation were identified by PCR amplification of cDNA inserts from genomic DNA isolated from leukemic cells. In an initial screen of ten leukemic mice, the MYC proto-oncogene was detected in all the leukemic mice. Of ten leukemic mice, 3 (30%) had MYC as the only transgene, and seven mice (70%) had additional proto-oncogene inserts. We repeated the same experiment after removing MYC-related genes from the library to characterize additional leukemia-inducing gene combinations. Our second screen using the MYC-deleted proto-oncogene library confirmed MEIS1and the HOX family as cooperating oncogenes in leukemia pathogenesis. The model system we introduced in this study will be valuable in functionally screening novel combinations of genes for leukemogenic potential in vivo, and the system will help in the discovery of new targets for leukemia therapy.

  9. cDNA library Table: Nnor [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available Nnor NA Nnor NA ovary-derived cell-line NA NA pBluescript SK- EcoR1 for 5' Xho1for 3' sequenced from T3 prim...er (5' -> 3') BY916644-BY916866 E_ET_Nnor_[number]_F_0,E_ET_Nnor_[number]_F_1 BmN normalized library ...

  10. 干旱胁迫的水稻根高效酵母双杂交体系建立%Construction and High-efficient Screenings of a Yeast Two-Hybrid cDNA Library from the Drought-stressed Roots of Rice

    Institute of Scientific and Technical Information of China (English)

    付坚; Linkun Gu; 郭怡卿; Liyuan ZHANG; 王玲仙; 李定琴; 王波; Jeff Qingxi SHEN; 程在全

    2013-01-01

    采用SMART技术在酵母菌株AH109中构建了干旱胁迫下水稻根部全长cDNA文库,采用改进的滤膜杂交方法建立了高效酵母杂交体系,以抗旱相关水稻转录调控因子OsWRKy71基因作为诱饵对该方法进行检验.实验获得的酵母杂交文库容量为4.9×10 6,平均插入片段为800 bp,达到了基因分离和克隆等后续研究的标准.同时采用滤膜杂交法将文库的杂交效率提高到了6.9%,是液体杂交法的6倍以上.该方法不需要特殊的设备,且具有低消耗和高效率的特点,可用于高通量酵母双杂交分析.%By using the SMART technique, a yeast two-hybrid cDNA library of rice roots was constructed and utilized to study protein-protein interactions induced by drought. An optimized high efficiency membrane mating method, substituting for liquid mating method, was developed for library screenings. As results, there are about 4. 9 × 106 clones in the library with the averaged size of the insert fragments to be about 800 base pairs. To verify the efficiency of the membrane mating method, OsWRKY71 , a well-studied gene encoding a transcriptional repressor of gibberellin signaling, was used as a bait to screen this library. The mating efficiency was shown to be as high as 6. 9% , which was six times higher than that of the liquid mating method. This high efficient mating method is simple, cost-effective and suitable for large scale yeast hybrid analyses.

  11. Construction of cDNA library and preliminary analysis of expressed sequence tags from Siberian tiger

    Directory of Open Access Journals (Sweden)

    Chang-Qing Liu, Tao-Feng Lu, Bao-Gang Feng, Dan Liu, Wei-Jun Guan, Yue-Hui Ma

    2010-01-01

    Full Text Available In this study we successfully constructed a full-length cDNA library from Siberian tiger, Panthera tigris altaica, the most well-known wild Animal. Total RNA was extracted from cultured Siberian tiger fibroblasts in vitro. The titers of primary and amplified libraries were 1.30×106 pfu/ml and 1.62×109 pfu/ml respectively. The proportion of recombinants from unamplified library was 90.5% and average length of exogenous inserts was 1.13 kb. A total of 282 individual ESTs with sizes ranging from 328 to 1,142bps were then analyzed the BLASTX score revealed that 53.9% of the sequences were classified as strong match, 38.6% as nominal and 7.4% as weak match. 28.0% of them were found to be related to enzyme/catalytic protein, 20.9% ESTs to metabolism, 13.1% ESTs to transport, 12.1% ESTs to signal transducer/cell communication, 9.9% ESTs to structure protein, 3.9% ESTs to immunity protein/defense metabolism, 3.2% ESTs to cell cycle, and 8.9 ESTs classified as novel genes. These results demonstrated that the reliability and representativeness of the cDNA library attained to the requirements of a standard cDNA library. This library provided a useful platform for the functional genomic research of Siberian tigers.

  12. Construction of cDNA representational difference analysis based on two cDNA libraries and identification of garlic inducible expression genes in human gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Yong Li; Lin Yang; Jian-Tao Cui; Wen-Mei Li; Rui-Fang Guo; You-Yong Lu

    2002-01-01

    AIM: To elucidate molecular mechanism of chemopreventiveefficacies of garlic against human gastric cancer (HGC):METHODS: HGC cell line BGC823 was treated with Allitridi (akind of garlic extract) and Allitridi-treated and parentalBGC823 cDNA librarles were constructed respectively byusing λZAP Ⅱ vector. cDNA Representatinal DifferenceAnalysis (cDNA RDA) was perfonmed using BamH Ⅰ cutting-site and abundant ~DNA messages provided by the Iibrarles.Northern blot analysls was applied to identifythe obtaineddifference prnducts.RESULTS: Two specific cDNA fragments were obtained andcharacterized to be derived from homo sapiens folatereceptorα (FRα) gene and calcyclin gene respectively.Northern blot results showed a 4-fold increase in FRα geneexpression level and 9-fold increase in calcyclin mRNA levelin BGC823 cells after Allilridi treatment for 72 h.CONCLUSION: The method of cDNA RDA based on cDNAlibraries combines the high specificity of cDNA RDA withabundant cDNA messages in cDNA library; this expands theapplication of cDNA library and increases the specificity ofcDNA RDA. Up-regulstion of FRα gene and calcyclin geneexpressions induced by Allitridi provide valuable molecularevidence for theefficacy of garlic in treating HGC as well asother diseases.

  13. Isolation of carrot Argonaute1 from subtractive somatic embryogenesis cDNA library.

    Science.gov (United States)

    Takahata, Kiminori

    2008-03-01

    Carrot Argonaute1 (C-Ago1) was isolated from a subtractive cDNA library to obtain somatic embryogenesis related genes. C-Ago1 has three conserved domains, which are found in all other Argonautes. C-Ago1 has specific expression during somatic embryogenesis, which indicates that microRNA gene expression controlling system is required for somatic embryogenesis.

  14. 黑曲霉H1的cDNA文库构建及其溶磷相关基因的筛选%Construction of cDNA library of Aspergillus niger H1 and screening of phosphate-dissolving related gene

    Institute of Scientific and Technical Information of China (English)

    唐超西; 龚明波; 李顺鹏; 朱昌雄

    2012-01-01

    [目的]构建溶磷黑曲霉H1的cDNA文库,并从中筛选溶磷相关基因.[方法]利用SMART技术合成黑曲霉H1的双链cDNA并将其连接于pBluescript Ⅱ SK(+)载体上,将重组质粒转化E.coli HST08,得到黑曲霉的初级cDNA文库.利用难溶磷培养基筛选具有溶磷能力的克隆子,测序并利用Blast分析基因序列.在难溶磷液体培养基中,进行克隆子对溶液pH值、可溶磷含量的影响和产有机酸实验.[结果]成功构建了黑曲霉H1的cDNA文库,其初级库容量约为5.65×106cfu/mL,重组率约为99.15%;通过难溶磷固体培养基筛选,得到具有溶磷圈的克隆子61个,其中克隆子H-54的cDNA序列长839 bp,基因编码氨基酸残基序列长179n.t.克隆子E.coli HST08 H-54在液体难溶磷培养基中培养,提高了有机酸的表达量,并增加了有机酸的种类,在培养12h后,溶液中开始产生甲酸和乙酸,在24 h后,溶液中产生苹果酸和α-酮戊二酸,培养36 h,溶液pH值由6.32降到3.93,可溶磷含量达到0.105 mg/mL.[结论]从黑曲霉H1中获得1个溶磷相关基因,将其命名为psgA.%[ Objective]To obtain phosphate-dissolving genes from cDNA library of Aspergillus niger HI. [Methods] The double-stranded cDNA was synthesized using switching mechanism at 5'end of RNA transcript technique and ligated to the vector pBluescript II SK ( + ). We transformed recombinant plasmid into E. Coli HST08, resulting in a primary cDNA library. We screened clones with phosphate-dissolving activities on the insoluble phosphate medium and blasted the sequence in National Center for Biotechnology Information (NCBI). To study the phosphate dissolving mechanisms of the cloned gene, we analyzed the changes of the pH value, the soluble phosphate content and the production of organic acids in the insoluble phosphate liquid medium inoculated with the clones harboring the phosphate-dissolving gene. [Results] A cDNA library of A. Niger HI was successfully constructed. Titer tests

  15. 与人巨细胞病毒UL128两种不同结构蛋白相互作用蛋白的筛选与分析%Screening of protein interacting with the transcript of UL128 gene showed two protein patterns by yeast two-hybrid from human fetus brain cDNA library

    Institute of Scientific and Technical Information of China (English)

    任高伟; 崔鑫; 马艳萍; 齐莹; 阮强; 孙峥嵘

    2010-01-01

    Objective Using yeast two-hybrid system to screen the proteins which can interact with the human cytomegalovirus (HCMV) UL128 which have two difference transcription structure from human fetus brain cDNA library, and compare the difference with structure and function of interacting proteins. Methods Two fragments of UL128 were amplified by 3'RACE and 5'RACE technology, the length are 519 bp and 642 bp, respectively. The "bait plasmid" (named as pGBKT7-UL128-519 bp and pGBKT7-UL128-642 bp) was constructed successfully. Using pGBKT7-UL128-519 bp and pGBKT7-UL128-642 bp as a bait, a human fetus brain cDNA was screened and the proteins interacting with UL128-519 bp and UL128-642 bp encoded protein were searched, and the positive clones were sequenced and analyzed by bioinformatic methods. Results EFEMP2 interacting with HCMV UL128-519 bp were identified, THY-1 interacting with HCMV UL128-642 bp were identified. Conclusion EFEMP2 and THY-1 proteins interacting with HCMV UL128-519 bp and UL128-642 bp in human fetus brain cDNA library were successfully screened, but same proteins weren't found from the proteins interacting with UL128-519 bp and UL128-642 bp protein, UL128-519 bp and UL128-642 bp protein may be play an different effect in the process of infect by HCMV.%目的 利用酵母双杂交系统从人胎脑cDNA文库中筛选与两种不同转录结构的人巨细胞病毒(HCMV)UL128编码蛋白相互作用的蛋白,比较两者相互作用蛋白之间的异同点.方法 通过3'RACE和5'RACE技术扩增出两种HCMV UL128片段,其大小分别为519 bp和642 bp,并将其成功构建到酵母诱饵表达载体pGBKT7中.将以上两种酵母表达载体分别转化到酵母菌AH109中,再将文库DNA转化到已含有酵母表达载体的AH109中,筛选与两种片段大小不同的UL128编码蛋白相互作用的人胎脑蛋白,并对筛选得到的阳性克隆进行测序和生物信息学分析.结果 筛出EFEMP2与UL128-519 bp编码蛋白相互作用,THY-1

  16. Construction of cDNA Library of Pyrocystis lunula(Pyrophyta)

    Institute of Scientific and Technical Information of China (English)

    SUI Zhenghong; Klaus V.Kowallik

    2004-01-01

    Complementary DNA library of a dinoflagellate Pyrocystis lunula was constructed for the purpose of expression sequence tags analysis. The RNA isolated from this alga was about 20 μg g-1 net cells, and the band intensity ratio of 28 S/18 S in electrophoresis pattern was nearly 1 to 1. Different cDNA/vector molar ratios were exploited in the ligating reaction to be optimized. The clones produced by cDNA/vector molar ratio of 3.75 to 1 were desirable, most of whose inserts were longer than 300 bp. The recombinants insert length of the unfractionation cDNA library was largely shorter than 500 bp. However, in the fractionation library made from high molecule weight cDNA parts, over seventy percent of the recombinants contained inserts longer than 1 kb, some of which were even longer than 3 kb. Operating concerns were discussed at the end.

  17. High-content screening of functional genomic libraries.

    Science.gov (United States)

    Rines, Daniel R; Tu, Buu; Miraglia, Loren; Welch, Genevieve L; Zhang, Jia; Hull, Mitchell V; Orth, Anthony P; Chanda, Sumit K

    2006-01-01

    Recent advances in functional genomics have enabled genome-wide genetic studies in mammalian cells. These include the establishment of high-throughput transfection and viral propagation methodologies, the production of large-scale cDNA and siRNA libraries, and the development of sensitive assay detection processes and instrumentation. The latter has been significantly facilitated by the implementation of automated microscopy and quantitative image analysis, collectively referred to as high-content screening (HCS), toward cell-based functional genomics application. This technology can be applied to whole genome analysis of discrete molecular and phenotypic events at the level of individual cells and promises to significantly expand the scope of functional genomic analyses in mammalian cells. This chapter provides a comprehensive guide for curating and preparing function genomics libraries and performing HCS at the level of the genome.

  18. Screening of tissues pooled cDNA library using probes by restricted fragments of BAC positive clones of ovine MHC%以绵羊MHC 区段BAC 克隆酶切片段为探针杂交筛选绵羊混合组织cDNA 文库

    Institute of Scientific and Technical Information of China (English)

    杨小亮; 白大章; 邱巍; 董慧芹; 李大全; 陈芳; 马润林; Hugh T Blair; 高剑峰

    2012-01-01

    Under the premise what we have known bacterial artificial chromosome(BAC) clone sequence information and gene annotation predicted in the Chinese Merino sheep major histocompatibility complex (MHC) region, the digested fragments from 6 BAC clones that were located in the MHC region of the Chinese Merino sheep genome BAC library, which were used to screen the cDNA library using plaque in situ hybridization as probes. The full length of positive cDNA clones (sequences) isolated were completely sequenced, and the sequences obtained were aligned with the corresponding known sequence information and the BAC clones with gene annotation. Meanwhile, the sequence similarity was searched in NCBI Blastn database. This work aimed at verification of accuracy of the gene annotation results and initial analysis of gene (sequence) function. At last, 27 positive cDNA clones (sequences) in total were screened through two runs of hybridization. It was also found that these sequences could be positioned in the corresponding BAC clones, and 25 sequences were located in exon area of the annotated gene. It was verified that 23 sequences had the highest sequence similarity with those in the Bos taurus by searching against the NCBI Blastn database; moreover, the function of these sequences were closely relate to immunology.%在已知中国美利奴羊MHC(Major histocompatibility complex)区段BAC(Bacterial artificial chromosome)克隆序列信息和预测的基因注释前提下,用位于中国美利奴羊基因组BAC 文库MHC 区段的6 个BAC 克隆酶切片段为探针,以噬菌斑原位杂交筛选法筛选中国美利奴羊混合组织cDNA 文库(库库杂交),对分离到的cDNA阳性克隆进行全序列测定,并与相应的已知序列信息和基因注释的BAC 克隆比对以及在NCBI Blastn 数据库中序列相似性检索,旨在验证基因注释结果的准确性和对基因(序列)功能的初步分析.实验中,经过两轮杂交共筛选出27 个cDNA 阳性克隆(序

  19. Construction of cDNA subtractive library from pearl oyster (Pinctada fucata Gould) with red color shell by SSH

    Institute of Scientific and Technical Information of China (English)

    GUAN Yunyan; HUANG Liangmin; HE Maoxian

    2011-01-01

    The molecular basis of color polymorphism in the shells of the pearl oyster Pinctada fucata is largely unknown. We developed a red-shelled family line and used suppression subtractive hybridization (SSH) to screen for differentially expressed genes in red- and non-red-shelled pearl oysters. We constructed forward and reverse cDNA subtractive libraries consisting of 2 506 and 797 clones, respectively.Among 343 randomly selected clones in the forward library, 304 sequences were identified in GenBank using BLASTx and BLASTn. Of the 304 sequences, 13 showed no similarity to known sequences and 291 were matched with known genes of the pearl oyster, including shematrin-1, shematrin-2, shematrin-6,shematrin-7, nacrein, nacrein-like protein, aspein for shell matrix protein, glycine-rich protein, mantle gene 5, 28S, EST00031, EST00036, 16S, and COI. In the reverse library, 7 clones were sequenced and analyzed by BLAST. Two sequences shared similarity with EST00036 from the P. fucata subtraction cDNA library, four with the P. fucata mitochondrial gene for 16S rRNA and 1 with P. fucata shematrin-2. We evaluated the expression of 12 genes from the forward library using RT PCR. Two sequences matched with 16S and COI so were considered to be false positives. The remaining 10 sequences were differentially expression in the red-shelled pearl oysters. Our results suggest that differential expression of these genes may be related to color variation in the red-shelled family line of the pearl oyster.

  20. Construction of cDNA subtractive library from pearl oyster ( Pinctada fucata Gould) with red color shell by SSH

    Science.gov (United States)

    Guan, Yunyan; Huang, Liangmin; He, Maoxian

    2011-05-01

    The molecular basis of color polymorphism in the shells of the pearl oyster Pinctada fucata is largely unknown. We developed a red-shelled family line and used suppression subtractive hybridization (SSH) to screen for differentially expressed genes in red- and non-red-shelled pearl oysters. We constructed forward and reverse cDNA subtractive libraries consisting of 2 506 and 797 clones, respectively. Among 343 randomly selected clones in the forward library, 304 sequences were identified in GenBank using BLASTx and BLASTn. Of the 304 sequences, 13 showed no similarity to known sequences and 291 were matched with known genes of the pearl oyster, including shematrin-1, shematrin-2, shematrin-6, shematrin-7, nacrein, nacrein-like protein, aspein for shell matrix protein, glycine-rich protein, mantle gene 5, 28S, EST00031, EST00036, 16S, and COI. In the reverse library, 7 clones were sequenced and analyzed by BLAST. Two sequences shared similarity with EST00036 from the P. fucata subtraction cDNA library, four with the P. fucata mitochondrial gene for 16S rRNA and 1 with P. fucata shematrin-2. We evaluated the expression of 12 genes from the forward library using RT PCR. Two sequences matched with 16S and COI so were considered to be false positives. The remaining 10 sequences were differentially expression in the red-shelled pearl oysters. Our results suggest that differential expression of these genes may be related to color variation in the red-shelled family line of the pearl oyster.

  1. Characterization of Expressed Sequence Tags From a Gallus gallus Pineal Gland cDNA Library

    OpenAIRE

    2005-01-01

    The pineal gland is the circadian oscillator in the chicken, regulating diverse functions ranging from egg laying to feeding. Here, we describe the isolation and characterization of expressed sequence tags (ESTs) isolated from a chicken pineal gland cDNA library. A total of 192 unique sequences were analysed and submitted to GenBank; 6% of the ESTs matched neither GenBank cDNA sequences nor the newly assembled chicken genomic DNA sequence, three ESTs aligned with sequences designated to be on...

  2. ISOLATION OF TUMOR DIFERENTIALLY EXPRESSED GENES BY MIXING PROBES LIBRARY SCREEN

    Institute of Scientific and Technical Information of China (English)

    余鹰; 朱诗国; 张必成; 周鸣; 李桂源; 沈守荣; 张晓梅

    2001-01-01

    Objective: This study was designed to clone candidate tumor suppressor genes down-expressed in Nasopharyngeal Carcinoma (NPC). Methods: Differentially expressed cDNA fragments (AF152605 and AF091517) were labeled by PCR, and Northern blot was used to confirmed transcript length of these genes. Skeleton muscle cDNA library was screened with PCR-labeled probe mixture. By sequencing the positive clones directly, three novel genes (Genbank accession number: AF179285, AF170307 and AF194971), with transcripts of 2.1 Kb, 1.1 Kb and 1.4 Kb respectively, were isolated successfully. Conclusions: Library screening using PCR-labeled probes mixture is an efficient method to get full-length cDNA from multi-cDNA fragment simultaneously and quickly.

  3. [Construction of subtractive cDNA libraries of the sporogony stage of Eimeria tenella by suppression subtractive hybridization].

    Science.gov (United States)

    Han, Hong-Yu; Lin, Jiao-Jiao; Zhao, Qi-Ping; Dong, Hui; Jiang, Lian-Lian; Wang, Xin; Han, Jing-Fang; Huang, Bing

    2007-11-01

    In order to clone and identify differentially expressed genes in the sporogony stage of Eimeria tenella, the cDNAs from unsporulated oocysts and sporulated oocysts of E. tenella were used as driver, respectively, the cDNAs from sporozoites of E. tenella was used tester, Two subtractive cDNA libraries of sporozoites were constructed by using the technique of suppression subtractive hybridization (SSH). the cDNAs from unsporulated oocysts was used driver, the cDNAs from sporulated ooceysts was used tester, one subtractive cDNA library of sporulated oocysts was constructed. PCR amplification revealed that the two subtractive cDNA libraries of sporozoites and one subtractive cDNA library of sporulated oocysts contained approximated 96%, 96% and 98% recombinant clones, respectively. Fifty positive clones were sequenced and analyzed in GenBank with Blast search from three subtractive cDNA libraries, respectively, thirteen unique sequences were found from the subtractive cDNA library of sporulated oocysts, eight ESTs shared significant identity with previously described. A total of forty unique sequences were obtained from the two subtractive cDNA libraries, nine ESTs shared significant identity with previously described, the other sequences represent novel genes of E. tenella with no significant homology to the proteins in Genbank. These results have provided the foundation for cloning new genes of E. tenella and further studying new approaches to control coccidiosis.

  4. Construction of Yeast Two-hybrid cDNA Library of Verticillium dahliae%大丽轮枝菌酵母双杂交 cDNA 文库的构建

    Institute of Scientific and Technical Information of China (English)

    康静敏; 刘坤; 刘严; 张怡; 李成伟; 谭光轩

    2015-01-01

    为了分离克隆与植物互作的大丽轮枝菌致病相关蛋白基因,利用 SMART 技术构建了大丽轮枝菌酵母双杂交 cDNA 文库。结果表明,构建的文库滴度为5.2×107 cfu/mL,库容为3.9×107 cfu;文库 cDNA 插入片段长度主要分布在0.5~2.0 kb,平均为1 kb;文库重组率为96%。表明文库质量较好,为筛选与植物互作的大丽轮枝菌致病蛋白基因奠定了基础。%To seek out the V. dahliae proteins involved in the interaction of plant with V. dahliae,a yeast two-hybrid library of V. dahliae was constructed using SMART technique. Results showed that the titer of cDNA library was 5. 2 × 107 cfu/mL,the library contained 3. 9 × 107 cfu independent clones,the size distribution of insert frag-ments ranged from 0. 5 -2. 0 kb,and the recombination rate was about 96%. These data demonstrated that the li-brary could meet the requirements of standard cDNA library,which laid a foundation for screening the interaction proteins from V. dahliae.

  5. Rapid Discovery of Functional Small Molecule Ligands against Proteomic Targets through Library-Against-Library Screening.

    Science.gov (United States)

    Wu, Chun-Yi; Wang, Don-Hong; Wang, Xiaobing; Dixon, Seth M; Meng, Liping; Ahadi, Sara; Enter, Daniel H; Chen, Chao-Yu; Kato, Jason; Leon, Leonardo J; Ramirez, Laura M; Maeda, Yoshiko; Reis, Carolina F; Ribeiro, Brianna; Weems, Brittany; Kung, Hsing-Jien; Lam, Kit S

    2016-06-13

    Identifying "druggable" targets and their corresponding therapeutic agents are two fundamental challenges in drug discovery research. The one-bead-one-compound (OBOC) combinatorial library method has been developed to discover peptides or small molecules that bind to a specific target protein or elicit a specific cellular response. The phage display cDNA expression proteome library method has been employed to identify target proteins that interact with specific compounds. Here, we combined these two high-throughput approaches, efficiently interrogated approximately 10(13) possible molecular interactions, and identified 91 small molecule compound beads that interacted strongly with the phage library. Of 19 compounds resynthesized, 4 were cytotoxic against cancer cells; one of these compounds was found to interact with EIF5B and inhibit protein translation. As more binding pairs are confirmed and evaluated, the "library-against-library" screening approach and the resulting small molecule-protein domain interaction database may serve as a valuable tool for basic research and drug development.

  6. Construction of human and mouse brain cDNA libraries and isolation of full-length cDNAs

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    cDNA libraries from aborted human 3-month fetal brain,adult rat and mouse brain were constructed by using a yZAP express cDNA library construction kin.Low molecular weight fragments of the second strand cDNASA were removed by flowing through the Sepharose CL-4B column and the frractionated long,Middle,Short fragments and the combined fragments weire respectively inserted into clone vectors to construct the cDNA libraries of the brain of human 3-month fetus.The 5'ends of 1200 clones from each of human fetal brain cDNA libraries were sequenced.A total of 894 ESTs were obtained and some full-length clones were squenced.By andalyaing the se-quences,12 novel full-length cDNAs were obtained.

  7. Large-scale screens of metagenomic libraries.

    Science.gov (United States)

    Pham, Vinh D; Palden, Tsultrim; DeLong, Edward F

    2007-01-01

    Metagenomic libraries archive large fragments of contiguous genomic sequences from microorganisms without requiring prior cultivation. Generating a streamlined procedure for creating and screening metagenomic libraries is therefore useful for efficient high-throughput investigations into the genetic and metabolic properties of uncultured microbial assemblages. Here, key protocols are presented on video, which we propose is the most useful format for accurately describing a long process that alternately depends on robotic instrumentation and (human) manual interventions. First, we employed robotics to spot library clones onto high-density macroarray membranes, each of which can contain duplicate colonies from twenty-four 384-well library plates. Automation is essential for this procedure not only for accuracy and speed, but also due to the miniaturization of scale required to fit the large number of library clones into highly dense spatial arrangements. Once generated, we next demonstrated how the macroarray membranes can be screened for genes of interest using modified versions of standard protocols for probe labeling, membrane hybridization, and signal detection. We complemented the visual demonstration of these procedures with detailed written descriptions of the steps involved and the materials required, all of which are available online alongside the video.

  8. Production of Arrayed and Rearrayed cDNA Libraries for Public Use

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, K

    2005-08-29

    Researchers studying genes and their protein products need an easily available source for that gene. The I.M.A.G.E. Consortium at Lawrence Livermore National Laboratory is an important source of such genes in the form of arrayed cDNA libraries. The arrayed clones and associated data are available to the public, free of restriction. Libraries are transformed and titered into 384-well master plates, from which 2-8 copies are made. One copy plate is stored by LLNL while others are sent to sequencing groups, plate distributors, and to the group which contributed the library. Clones found to be unique and/or full-length are rearrayed and also made publicly available. Bioinformatics tools supporting the use of I.M.A.G.E. clones are accessible via the World Wide Web.

  9. Identification and characterization of a new autoimmune protein in membranous nephropathy by immunoscreening of a renal cDNA library.

    Directory of Open Access Journals (Sweden)

    Fabrizio Cavazzini

    Full Text Available Membranous Nephropathy (MN represents a large amount of Nephrotic Syndromes in the adult population and its definitive diagnosis is currently carried out through biopsy. An autoimmune condition has been demonstrated in idiopathic MN (iMN in which some kidney structures are targeted by patient autoantibodies. Some candidate antigens have been described and other likely involved target proteins responsible for the disease are not known yet. In this work our aim is to identify these proteins by screening a lambda-phage library with patients' sera. We enrolled four groups of patients: two MN groups of 12 full iMN patients; one control group of 15 patients suffering from other renal diseases; one control group of 15 healthy individuals. A commercial cDNA phagemide library was screened using the above described sera, in order to detect positive signals due to antigen-antibody bond. We detected one phagemide clone expressing a protein which was shown to be targeted by the antibodies of the iMN sera only. Control sera were negative. The sequence analysis of cDNA matched the Synaptonemal Complex protein 65 (SC65 coding sequence. Further proteomic analyses were carried out to validate our results. We provide evidence of an involvement of SC65 protein as an autoimmune target in iMN. Considering the invasiveness and the resulting risk coming from renal biopsy, our ongoing aim is to set a procedure able to diagnose affected patients through a little- or non-invasive method such as blood sampling rather than biopsy.

  10. Construction of the Subtracted cDNA Library of Striatal Neurons Treated with Long-term Morphine

    Institute of Scientific and Technical Information of China (English)

    Bo Bai; Hai-qing Liu; Jing Chen; Ya-lin Li; Hui Du; Hai Lu; Peng-li Yu

    2011-01-01

    Objective To construct a morphine tolerance model in primarily cultured striatal neurons, and screen the differentially expressed genes in this model using suppression subtractive hybridization (SSH).Methods Sbtracted cDNA libraries were constructed using SSH from normal primarily cultured striatal neurons and long-term morphine treated striatal neurons (10-5 mol/L for 72 hours). To check reliability of the cell culture model, RT-PCR was performed to detect the cAMP-responsive element-binding protein (CREB) mRNA expression. The subtracted clones were prescreened by PCR. The clones containing inserted fragments from forward libraries were sequenced and submitted to GenBank for homology analysis. And the expression levels of genes of interest were confirmed by RT-PCR. Results CREB mRNA expression showed a significant increase in morphine treated striatal neurons (62.85±1.98) compared with normal striatal neurons (28.43±1.46, P<0.01). Thirty-six clones containing inserted fragments were randomly chosen for sequence analysis. And the 36 clones showed homology with 19 known genes and 2 novel genes. The expression of 2 novel genes, mitochondrial carrier homolog 1 (Mtch1; 96.81±2.04 vs. 44.20±1.31, P<0.01) and thymoma viral proto-oncogene 1 (Akt1; 122.10±2.17 vs. 50.11 ±2.01, P<0.01), showed a significant increase in morphine-treated striatal neurons compared with normal striatal neurons. Conclusions A reliable differential cDNA library of striatal neurons treated with long-term morphine is constructed. Mtchl and Akt1 might be the candidate genes for the development of morphine tolerance.

  11. [Construction and analysis of subtractive cDNA library of Phellodendron amurense under drought stress].

    Science.gov (United States)

    Wang, Huimei; Wang, Yanbing; Zu, Yuangang; Sun, Lianhui

    2008-02-01

    With cDNA from Phellodendron amurense seedlings treated with drought stress as tester and cDNA from this plant in normal growth as driver, we construct cDNA subtracted library using suppression subtractive hybridization (SSH). In the library, the rate of recombination was 95%, the size of inserts was 300-800 bp. Two hundred and sixty-five new genes were obtained by DNA sequencing 816 positive clones picked randomly, and partitioned to 16 classes after nucleotide Blast and BlastX homological analysis against NT, NR, SWISSPROT, KEGG database. Forty-four drought stress associated genes, such as heat shock protein cognate 70, dehydration responsive protein 22, universal stress protein, metallothionein II, late embryogenesis abundant protein, were obtained, which made 16.6% of the overall genes. These genes included osmotic regulator, signal component regulatory protein and antioxidant enzyme. The research had established a basis for cloning stress resistance genes and further studying genes expression in P. amurense seedlings under drought stress.

  12. Analysis of cDNA libraries from developing seeds of guar (Cyamopsis tetragonoloba (L. Taub

    Directory of Open Access Journals (Sweden)

    Dixon Richard A

    2007-11-01

    Full Text Available Abstract Background Guar, Cyamopsis tetragonoloba (L. Taub, is a member of the Leguminosae (Fabaceae family and is economically the most important of the four species in the genus. The endosperm of guar seed is a rich source of mucilage or gum, which forms a viscous gel in cold water, and is used as an emulsifier, thickener and stabilizer in a wide range of foods and industrial applications. Guar gum is a galactomannan, consisting of a linear (1→4-β-linked D-mannan backbone with single-unit, (1→6-linked, α-D-galactopyranosyl side chains. To better understand regulation of guar seed development and galactomannan metabolism we created cDNA libraries and a resulting EST dataset from different developmental stages of guar seeds. Results A database of 16,476 guar seed ESTs was constructed, with 8,163 and 8,313 ESTs derived from cDNA libraries I and II, respectively. Library I was constructed from seeds at an early developmental stage (15–25 days after flowering, DAF, and library II from seeds at 30–40 DAF. Quite different sets of genes were represented in these two libraries. Approximately 27% of the clones were not similar to known sequences, suggesting that these ESTs represent novel genes or may represent non-coding RNA. The high flux of energy into carbohydrate and storage protein synthesis in guar seeds was reflected by a high representation of genes annotated as involved in signal transduction, carbohydrate metabolism, chaperone and proteolytic processes, and translation and ribosome structure. Guar unigenes involved in galactomannan metabolism were identified. Among the seed storage proteins, the most abundant contig represented a conglutin accounting for 3.7% of the total ESTs from both libraries. Conclusion The present EST collection and its annotation provide a resource for understanding guar seed biology and galactomannan metabolism.

  13. Study on Wusan Granule Anti-tumor Related Target Gene Screened by Cdna Microarray

    Institute of Scientific and Technical Information of China (English)

    YOU Zi-li; SHI Jin-ping; CHEN Hai-hong

    2006-01-01

    To screen Wusan Granule anti-tumor related target gene using cDNA microarray technique, both mRNA from Lewis lung carcinoma tissues treated by Wusan Granule and untreated control are reversibly transcribed to prepare cDNA probes which are labeled by Cy5 and Cy3. Then, the probes are hybridized to the mice cDNA microarray type MGEC-20S. After hybridization, the cDNA microarray is scanned by ScanArray 3 000 scanner and the data is analyzed by ImaGene 3 software to screen the differentially expressed genes. There are 45 differentially expressed genes including 18 known genes and 27 unknown genes between the two groups, and among them, 20 elevated genes and 25 reduced genes are identified. Additionally, the genes related to invasion and metastasis of malignant carcinomas are down-regulated and the genes related to apoptosis are up-regulated. The cDNA microarray technique is a high-throughput approach to screen the Wusan Granule anti-tumor related target genes, which allow us to explore the molecular biological mechanism on a genomic scale.

  14. Optimization of RNA isolation from Brittle Leaf Disease affected date palm leaves and construction of a subtractive cDNA library.

    Science.gov (United States)

    Saïdi, Mohammed Najib; Gargouri-Bouzid, Radhia; Rayanni, Mariem; Drira, Noureddine

    2009-01-01

    A simple and efficient method was described here for the isolation of high-quality RNA from date palm leaves affected with Brittle Leaf Disease (BLD) and containing high amount of phenolic compounds. The procedure was based on the use of a non-ionic detergent Nonidet-P40 (NP-40), Polyvinylpyrrolidone (PVP), and beta-mercaptoethanol in the extraction buffer in order to isolate cytoplasmic RNA and to prevent the oxidation of phenolic compounds. This method allowed the isolation of intact RNA, suitable for cDNA synthesis and library construction. Differential screening of the subtractive cDNA library from affected leaf RNA led to the identification of some BLD-induced genes.

  15. 人胰腺细胞cDNA 文库中丙型肝炎病毒NS4B 结合蛋白基因的筛选%Screening of proteins binding to hepatitis C virus NS4B protein from human pancreas cDNA library

    Institute of Scientific and Technical Information of China (English)

    温少芳; 张锦前; 孙荣华; 李卓; 高萍; 王琦; 刘顺爱; 成军

    2011-01-01

    Objective To screen proteins from human pancreas cDNA library , which interact with the protein coded hy hepatitis C virus ( HCV) NS4B. Methods The reconstructed plasmid pGBKT7-NS4B was transformed into yeast strain AH109 and identified. The transformed AH109 ( pGBKT7-NS4B) mated with Y187 ( plasmids of pancreatic cDNA library ) . The diploid yeast cells were plated on nutrient deficiency medium containing X-α-gal for selecting. The plasmids in diploid yeast cells were extracted and electrotransformed into E. c.oli DH5a. The plasmids in DH5α were extracted, sequenced and blasted.Results Seven proteins interacting with HCV NS4B were found . such as CDK5RAP3 , colipase , pancreatic stone protein ,lactoprotein . elastase2A , chymotrypsin and bile salt-stimulated esterase . Conclusions Some of the eight pancreatic proteins may be related with metaholisms of glucose and lipid .%目的 从人胰腺细胞cDNA 文库中,采用酵母双杂交方法 筛选HCV NS4B 包膜蛋白的相互作用蛋白.方法 人胰腺细胞cDNA 文库先进行扩增,随后纯化及鉴定,然后将鉴定好的人胰腺细胞cDNA 文库质粒转化入酵母菌株Y187.构建pGBKT7-NS4B 作为诱饵质粒,随之转化酵母菌株AH109,用色氨酸缺陷型培养基(SD/-Trp)筛选阳性菌落.配合两种重组酵母菌株AH109 与Y187,用四缺培养基及X-α-gal 筛选蓝色酵母菌落,提取相应质粒,电转化感受态菌DH5α后再提取质粒,测序仪测序,结果 使用PUBMED 进行序列比对.结果 成功构建pGBKT7-HCV NS4B 重组质粒,并从人胰腺cDNA 文库中筛选出7 种与HCV NS4B 蛋白相结合的蛋白基因,包括CDK5RAP3、辅脂肪酶、胰石蛋白、凝乳蛋白、弹性蛋白酶2A、糜蛋白酶和胆盐刺激酯酶.结论 HCV NS4B 蛋白可能通过与所筛选出前述蛋白中参与代谢过程的相关蛋白结合,影响糖、脂类代谢过程.

  16. Human BAC library: construction and rapid screening.

    Science.gov (United States)

    Asakawa, S; Abe, I; Kudoh, Y; Kishi, N; Wang, Y; Kubota, R; Kudoh, J; Kawasaki, K; Minoshima, S; Shimizu, N

    1997-05-20

    We have constructed a human genomic bacterial artificial chromosome (BAC) library using high molecular weight DNA from a pre-pro-B cell line, FLEB14-14, with a normal male diploid karyotype. This BAC library consists of 96,000 clones with an average DNA insert size of 110 kb, covering the human genome approximately 3 times. The library can be screened by three different methods. (1) Probe hybridization to 31 high-density replica (HDR) filters: each filter contains 3072 BAC clones which were gridded in a 6 x 6 pattern. (2) Probe hybridization to two Southern blot filters to which 31 HindIII digests of the pooled 3072 BAC clones were loaded. This identifies a particular HDR filter for which further probe hybridization is performed to identify a particular clone(s). (3) Two-step polymerase chain reaction (PCR). First, PCR is applied to DNA samples prepared from ten superpools of 9600 BAC clones each to identify a particular superpool and the second PCR is applied to 40 unique DNA samples prepared from the four-dimensionally assigned BAC clones of the particular superpool. We present typical examples of the library screening using these three methods. The two-step PCR screening is particularly powerful since it allows us to isolate a desired BAC clone(s) within a day or so. The theoretical consideration of the advantage of this method is presented. Furthermore, we have adapted Vectorette method to our BAC library for the isolation of terminal sequences of the BAC DNA insert to facilitate contig formation by BAC walking.

  17. Sequence characterization of a human embryonic craniofacial cDNA library

    Energy Technology Data Exchange (ETDEWEB)

    Padanilam, B.J.; Barsel, S.; Solursh, M. [and others

    1994-09-01

    Broad-based sequencing approaches for the characterization of human cDNA libraries have proven successful in identifying large numbers of novel genes of specific tissue or developmental stages. To pursue our interests in human craniofacial development, stages. To pursue our interests in human craniofacial development, we have made use of both subtracted and unsubtracted cDNA libraries constructed from embryonic craniofacial tissue obtained from pooled samples at 42-54 days gestation. Single-pass sequencing was carried out using an ABI automated sequencer and T3 or T7 primers. Sequences were characterized using BLAST and GRAIL, and the identified homologous sequences grouped according to gene class and family. Four genes have been mapped using repeat sequence elements identified in the clones. Using primers developed from sequence data, other genes are being mapped using a panel of somatic cell hybrids. To date, a total of 786 sequences have been returned with 35% identifying no homologies, and 35% with strong homologies to previously identified genes. A number of genes previously identified to play a role in human embryonic development have been returned from the sequence comparisons providing evidence that the library is representative of this tissue and stage of development. Previous characterization of the library has also identified a number of novel embryonically expressed human homeobox genes. Genes felt to be of special relevance based on their homology to characterized genes known to play a role in development or that are members of novel classes but with high scores on GRAIL searches are being characterized using whole mount in situ hybridization with mouse embryos. Characterization of the library with respect to chromosomal mapping, gene types and make-up, and embryonic expression patterns will be presented.

  18. Efficient and simpler method to construct normalized cDNA libraries with improved representations of full-length cDNAs

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Marcelo Bento (New York, NY); Bonaldo, Maria de Fatima (New York, NY)

    1998-01-01

    This invention provides a method to normalize a cDNA library comprising: (a) constructing a directionally cloned library containing cDNA inserts wherein the insert is capable of being amplified by polymerase chain reaction; (b) converting a double-stranded cDNA library into single-stranded DNA circles; (c) generating single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) by polymerase chain reaction with appropriate primers; (d) hybridizing the single-stranded DNA circles converted in step (b) with the complementary single-stranded nucleic acid molecules generated in step (c) to produce partial duplexes to an appropriate Cot; and (e) separating the unhybridized single-stranded DNA circles from the hybridized DNA circles, thereby generating a normalized cDNA library. This invention also provides a method to normalize a cDNA library wherein the generating of single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) is by excising cDNA inserts from the double-stranded cDNA library; purifying the cDNA inserts from cloning vectors; and digesting the cDNA inserts with an exonuclease. This invention further provides a method to construct a subtractive cDNA library following the steps described above. This invention further provides normalized and/or subtractive cDNA libraries generated by the above methods.

  19. Efficient and simpler method to construct normalized cDNA libraries with improved representations of full-length cDNAs

    Energy Technology Data Exchange (ETDEWEB)

    Soares, M.B.; Fatima Bonaldo, M. de

    1998-12-08

    This invention provides a method to normalize a cDNA library comprising: (a) constructing a directionally cloned library containing cDNA inserts wherein the insert is capable of being amplified by polymerase chain reaction; (b) converting a double-stranded cDNA library into single-stranded DNA circles; (c) generating single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) by polymerase chain reaction with appropriate primers; (d) hybridizing the single-stranded DNA circles converted in step (b) with the complementary single-stranded nucleic acid molecules generated in step (c) to produce partial duplexes to an appropriate Cot; and (e) separating the unhybridized single-stranded DNA circles from the hybridized DNA circles, thereby generating a normalized cDNA library. This invention also provides a method to normalize a cDNA library wherein the generating of single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) is by excising cDNA inserts from the double-stranded cDNA library; purifying the cDNA inserts from cloning vectors; and digesting the cDNA inserts with an exonuclease. This invention further provides a method to construct a subtractive cDNA library following the steps described above. This invention further provides normalized and/or subtractive cDNA libraries generated by the above methods. 25 figs.

  20. Colony color assay coupled with 5FOA negative selection greatly improves yeast threehybrid library screening efficiency

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The recently developed yeast three-hybrid system is a powerful tool for analyzing RNA-protein interactions in vivo. However, large numbers of false positives are frequently met due to bait RNA-independent activation of the reporter gene in the library screening using this system. In this report, we coupled the colony color assay with the 5FOA (5-fluoroorotic acid) negative selection in the library screening, and found that this coupled method effectively eliminated bait RNA-independent false positives and hence greatly improved library screening efficiency. We used this method successfully in isolation of cDNA of an RNA-binding protein that might play important roles in certain cellular process. This improvement will facilitate the use of the yeast three-hybrid system in analyzing RNA-protein interaction.

  1. Discovery of Phytophthora infestans genes expressed in planta through mining of cDNA libraries.

    Directory of Open Access Journals (Sweden)

    Roberto Sierra

    Full Text Available BACKGROUND: Phytophthora infestans (Mont. de Bary causes late blight of potato and tomato, and has a broad host range within the Solanaceae family. Most studies of the Phytophthora--Solanum pathosystem have focused on gene expression in the host and have not analyzed pathogen gene expression in planta. METHODOLOGY/PRINCIPAL FINDINGS: We describe in detail an in silico approach to mine ESTs from inoculated host plants deposited in a database in order to identify particular pathogen sequences associated with disease. We identified candidate effector genes through mining of 22,795 ESTs corresponding to P. infestans cDNA libraries in compatible and incompatible interactions with hosts from the Solanaceae family. CONCLUSIONS/SIGNIFICANCE: We annotated genes of P. infestans expressed in planta associated with late blight using different approaches and assigned putative functions to 373 out of the 501 sequences found in the P. infestans genome draft, including putative secreted proteins, domains associated with pathogenicity and poorly characterized proteins ideal for further experimental studies. Our study provides a methodology for analyzing cDNA libraries and provides an understanding of the plant--oomycete pathosystems that is independent of the host, condition, or type of sample by identifying genes of the pathogen expressed in planta.

  2. Primary analysis of the expressed sequence tags in a pentastomid nymph cDNA library.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    Full Text Available BACKGROUND: Pentastomiasis is a rare zoonotic disease caused by pentastomids. Despite their worm-like appearance, they are commonly placed into a separate sub-class of the subphylum Crustacea, phylum Arthropoda. However, until now, the systematic classification of the pentastomids and the diagnosis of pentastomiasis are immature, and genetic information about pentastomid nylum is almost nonexistent. The objective of this study was to obtain information on pentastomid nymph genes and identify the gene homologues related to host-parasite interactions or stage-specific antigens. METHODOLOGY/PRINCIPAL FINDINGS: Total pentastomid nymph RNA was used to construct a cDNA library and 500 colonies were sequenced. Analysis shows one hundred and ninety-seven unigenes were identified. In which, 147 genes were annotated, and 75 unigenes (53.19% were mapped to 82 KEGG pathways, including 29 metabolism pathways, 29 genetic information processing pathways, 4 environmental information processing pathways, 7 cell motility pathways and 5 organismal systems pathways. Additionally, two host-parasite interaction-related gene homologues, a putative Kunitz inhibitor and a putative cysteine protease. CONCLUSION/SIGNIFICANCE: We first successfully constructed a cDNA library and gained a number of expressed sequence tags (EST from pentastomid nymphs, which will lay the foundation for the further study on pentastomids and pentastomiasis.

  3. Construction and characterization of a cDNA library from human liver tissue with chronic hepatitis B

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-hong; CHEN Zhi; YAO Hang-ping; CHEN Feng; ZHU Hai-hong; ZHOU Hong-juan

    2005-01-01

    Objective: To construct a cDNA library from human liver tissue with chronic hepatitis B and check its quality for investigating the expression level of liver tissue infected by hepatitis B virus. This will then be used to find the relevant genes and interesting proteins associated with the development of hepatitis B. Methods: The total RNA from liver tissue with chronic hepatitis B was extracted and the mRNA was purified using TRIZOL method. Switching mechanism at 5' end of the RNA transcript(SMART) technique and CDS Ⅲ/3' primer were used for first-strand cDNA synthesis. Long distance polymerase chain reaction(LD PCR) was then used to synthesize the double-strand cDNA that was then digested by Sfi I and fractionated by CHROMA SPIN-400 column. The longer than 0.4 kb cDNAs were collected and ligated to λTriplEx2 vector. Then λ phage packaging reaction and library amplification were performed. The qualities of both unamplified and amplified cDNA libraries were strictly checked by conventional titer determination. Fourteen plaques were randomly picked and tested using PCR with universal primers derived from the sequence flanking the vector. Results: The titers of unamplifed and amplified libraries were 1.94×106 pfu/ml and1.49×109 pfu/ml respectively. The percentages of recombinants from both libraries were 98.15% in unamplified library and98.76% in amplified library. The lengths of the inserts were 1.23 kb in average, 1-2 kb in 64.29%, and 0.5-1.0 kb in 35.71%.Conclusion: A high quality cDNA library from human liver tissue with chronic hepatitis B was successfully constructed.

  4. Screening of TACE Peptide Inhibitors from Phage Display Peptide Library

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To obtain the recombinant tumor necrosis factor-α converting enzyme (TACE) ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coding catalytic domain (T800) and full-length ectodomain (T1300) of TACE were amplified by RTPCR, and the expression plasmids were constructed by inserting T800 and T1300 into plasmid pET28a and pET-28c respectively. The recombinant T800 and T1300 were induced by IPTG, and SDSPAGE and Western blotting analysis results revealed that T800 and T1300 were highly expressed in the form of inclusion body. After Ni2+-NTA resin affinity chromatography, the recombinant proteins were used in the screening of TACE-binding peptides from phage display peptide library respectively. After 4 rounds of biopanning, the positive phage clones were analyzed by ELISA, competitive inhibition assay and DNA sequencing. A common amino acid sequence (TRWLVYFSRPYLVAT) was found and synthesized. The synthetic peptide could inhibit the TNF-α release from LPS-stimulated human peripheral blood mononuclear cells (PBMC) up to 60.3 %. FACS analysis revealed that the peptide mediated the accumulation of TNF-α on the cell surface. These results demonstrate that the TACE-binding peptide is an effective antagonist of TACE.

  5. Construction and characterization of a full-lengh cDNA library from non-fresh Giardia lamblia

    Institute of Scientific and Technical Information of China (English)

    Jun-Li Guo; Jie Jiang; Wen-Yu Zheng; Ming-Luan Li; Xi-Feng Tian; Xian-Min Feng; Yue-Hua Wang; Xiao-Hong Ju; Yue-Qiong Kong

    2012-01-01

    Objective: To construct rapidly a full-length cDNA library from nanogram amounts total RNA of Giardia lamblia (G. lamblia) trophozoites stocked in RNA stabilization reagent. Methods: Total RNA of Giardia was extracted using Trizol reagent. A full-length cDNA library of G. lamblia trophozoites was constructed by a long-distance PCR (LD-PCR) method. The recombinant rate and the coverage rate of full-length clones of the library were evaluated. The inserted fragments were identified and sequenced by PCR amplification. Results: The titer of cDNA library was 3.85 ×107 pfu/mL. The length of inserted fragments ranged from 0.4 to 2.5 kb, and the recombination efficiency accounted for 100% (20/20). The coverage rate of full-length clones is high (17/20). Conclusions: The RNA stabilization reagent may be used to fix the cells and prevent the RNA in cells even though delivered under normal atmospheric temperature. The long-distance PCR can be used to construct a full-length cDNA library rapidly and it needs less RNA than the traditional method from mRNA.

  6. Construction of Hypericin Gland-Specific cDNA Library via Suppression Subtractive Hybridization.

    Science.gov (United States)

    Singh, Rupesh Kumar; Hou, Weina; Franklin, Gregory

    2016-01-01

    Hypericin, an important determinant of the pharmacological properties of the genus Hypericum, is considered as a major molecule for drug development. However, biosynthesis and accumulation of hypericin is not well understood. Identification of genes differentially expressed in tissues with and without hypericin accumulation is a useful strategy to elucidate the mechanisms underlying the development of the dark glands and hypericin biosynthesis. Suppression Subtractive Hybridization (SSH) is a unique method for PCR-based amplification of specific cDNA fragments that differ between a control (driver) and experimental (tester) transcriptome. This technique relies on the removal of dsDNA formed by hybridization between a control and test sample, thus eliminating cDNAs of similar abundance, and retaining differentially expressed or variable in sequence cDNAs. In our laboratory we applied this method to identify the genes involved in the development of dark glands and accumulation of hypericin in Hypericum perforatum. Here we describe the complete procedure for the construction of hypericin gland-specific subtracted cDNA library.

  7. Construction and quality analysis of cDNA library from flower buds of spring soybean cultivars%春大豆花芽 cDNA 文库的构建及质量分析

    Institute of Scientific and Technical Information of China (English)

    王楠; 周莹; 姚丹; 尹俊琦; 曲静; 王丕武

    2014-01-01

    [目的]为了解大豆多荚、多粒相关基因的调控机制,构建了大豆花芽cDNA文库,根据要求初步鉴定了所构建文库的质量.[方法]以大豆吉农18突变体的幼嫩花芽为材料提取总RNA,采用SMART技术合成双链cDNA.经蛋白酶K的消化及SfiⅠ酶切后,将所得cDNA克隆到λTriplEx质粒载体中,成功构建了大豆花芽全长cDNA文库.[结果和结论]将初始文库经扩增后保存,检测扩增文库滴度为2.13×108 pfu/mL,重组率接近95.3%,菌落PCR鉴定插入片段主要分布在0.5~2.0 kb .插入片段平均大小在1.0 kb左右.表明本研究所构建的文库既满足了目的基因的分离筛选,又可保证全长cDNA文库的获得,该文库的构建为进一步开展相关基因的克隆及分子生物学研究奠定基础.%[Objective] To understand soybean pods and multigrain gene regulation mechanisms of impro-ving soybean production , a soybean flower bud cDNA library was constructed .The quality of library con-struction was initially identified according to the requirements .[Method]In order to study the novel genes from flower bud mutants of soybean , a full-length cDNA library from flower bud mutants of soybean Jinong 18 was constructed .Total RNA from young flower bud mutants of soybean was extracted .Double strand cDNA was synthesized by SMART method .After proteinase K digestion and SfiⅠ digestion , the ds cDNA fragments were ligated to the λTriplEx vector .A cDNA library of soybean was successfully con-structed .[Result and conclusion]With the unamplified library stored after amplification , the titer of the amplified library was estimated as 2.13 ×108 pfu/mL and the recombination rate was approximately 95.3%.PCR results showed that the inserts varied from 0.5 to 2.0 kb with an average size of 1.0 kb or so.It indicated that this library could be used for full-length genes screening and cloning of low abundance genes.The library will lay a

  8. Genomic libraries: I. Construction and screening of fosmid genomic libraries.

    Science.gov (United States)

    Quail, Mike A; Matthews, Lucy; Sims, Sarah; Lloyd, Christine; Beasley, Helen; Baxter, Simon W

    2011-01-01

    Large insert genome libraries have been a core resource required to sequence genomes, analyze haplotypes, and aid gene discovery. While next generation sequencing technologies are revolutionizing the field of genomics, traditional genome libraries will still be required for accurate genome assembly. Their utility is also being extended to functional studies for understanding DNA regulatory elements. Here, we present a detailed method for constructing genomic fosmid libraries, testing for common contaminants, gridding the library to nylon membranes, then hybridizing the library membranes with a radiolabeled probe to identify corresponding genomic clones. While this chapter focuses on fosmid libraries, many of these steps can also be applied to bacterial artificial chromosome libraries.

  9. Construction and screening of marine metagenomic libraries.

    Science.gov (United States)

    Weiland, Nancy; Löscher, Carolin; Metzger, Rebekka; Schmitz, Ruth

    2010-01-01

    Marine microbial communities are highly diverse and have evolved during extended evolutionary processes of physiological adaptations under the influence of a variety of ecological conditions and selection pressures. They harbor an enormous diversity of microbes with still unknown and probably new physiological characteristics. Besides, the surfaces of marine multicellular organisms are typically covered by a consortium of epibiotic bacteria and act as barriers, where diverse interactions between microorganisms and hosts take place. Thus, microbial diversity in the water column of the oceans and the microbial consortia on marine tissues of multicellular organisms are rich sources for isolating novel bioactive compounds and genes. Here we describe the sampling, construction of large-insert metagenomic libraries from marine habitats and exemplarily one function based screen of metagenomic clones.

  10. Identification of some unknown transcripts from SSH cDNA library of buffalo follicular oocytes.

    Science.gov (United States)

    Rajput, S K; Kumar, P; Roy, B; Verma, A; Pandey, H P; Singh, D; De, S; Datta, T K

    2013-03-01

    A buffalo oocyte-specific subtracted cDNA library was constructed to identify exclusively or preferentially oocyte-expressed genes. The library represented an enriched population of transcripts obtained from oocytes of diverse ovarian follicular origin and at different stages of in vitro maturation. A total of 1173 high-quality sequences of oocyte-specific genes were clustered into 645 unique sequences, out of which 65.76% were represented as singlets and 34.26% as contig expressed sequence tags (ESTs; clusters). Analysis of sequences revealed that 498 of these sequences were identified as a known sequence in mammalian species including buffalo, 103 as uncharacterized ESTs and 44 unknown sequences including 1 novel EST, so far not reported in any species. Gene ontology annotation classified these sequences into functional categories of cellular events and biological processes associated with oocyte competence. Expression status of the isolated unknown ESTs confirmed that many of these are expressed in oocytes exclusively and in others preferentially, some in excess of 80-fold greater in comparison with a variety of somatic tissues. The isolated novel EST was detected to be expressed exclusively in oocytes and testicular cells only. To our knowledge, this is the first report giving a detailed transcriptome account of oocyte-expressed genes in buffalo. This study will provide important information on the physiological control of oocyte development, as well as many questions yet to be addressed on the reproductive process of buffalo.

  11. Construction of a hepatic stellate cells subtracted cDNA library of differentially expressed genes in normal mice and mice with Schistosomiasis japonica*

    OpenAIRE

    2005-01-01

    To construct a hepatic stellate cells (HSCs) subtracted cDNA library to find differentially expressed genes in normal mice and mice infected with Schistosoma japonicum (S. japonicum). Suppression subtractive hybridization (SSH) was used. The cDNA fragments of normal mouse were compared to those of schistosoma-infected mice to find differentially expressed genes. Then differentially expressed cDNA fragments were directly inserted into T/A cloning vector to set up the subtractive library. Ampli...

  12. Construction and selection of subtracted cDNA library of mouse hepatocarcinoma cell lines with different lymphatic metastasis potential

    Institute of Scientific and Technical Information of China (English)

    Li Hou; Jan-Wu Tang; Xiao-Nan Cui; Bo Wang; Bo Song; Lei Sun

    2004-01-01

    AIM: In order to elucidate the molecular mechanism of lymphatic metastasis of hepatocarcinoma, we detected the difference of gene expression between mouse hepatocarcinoma cell lines Hca-F and Hca-P with different lymphatic metastasis potential.METHODS: cDNA of Hca-F cells was used as a tester and cDNA of Hca-P cells was used as a driver. cDNAs highly expressed in Hca-F cells were isolated by the suppression subtractive hybridization (SSH) method. The isolated cDNA was cloned into T/A cloning vector. The ligation products were transformed into DH5 α competent cells. Individual clones were randomly selected and used for PCR amplification.Vector DNA from positive clones was isolated for sequencing.RESULTS: There were 800 positive clones in amplified subtracted cDNA library. Random analysis of 160 clones with PCR showed that 95% of the clones contained 100-700 bp inserts. Analysis of 20 sequenced cDNA clones randomly picked from the SSH library revealed 4 known genes (mouse heat shock protein 84 ku, DNA helicase, ribosomal protein S13 ,ethanol induced 6 gene) and 3 expressed sequence tags (ESTs). Four cDNAs showed no homology and presumably represent novel genes.CONCLUSION: A subtracted cDNA library of differentially expressed genes in mouse heptocarcinoma cell lines with different lymphatic metastasis potential was successfully constructed with SSH and T/A cloning techniques. The library is efficient and lays a solid foundation for searching new lymphatic metastasis related genes. The expression of mouse heat shock protein gene, DNA helicase and other 4 novel gene may be different between mouse heptocarcinoma cell lines with different lymphatic metastasis potential.

  13. New algebraic constructions for pooling design in DNA library screening.

    Science.gov (United States)

    Li, Zengti; Gao, Suogang; Du, Hongjie; Shi, Yan

    2010-01-01

    Pooling design is an important mathematical tool in DNA library screening. It has been showed that using pooling design, the number of tests in DNA library screening can be greatly reduced. In this paper, we present some new algebraic constructions for pooling design.

  14. Self-encoding resin beads of combinatorial library screening

    Science.gov (United States)

    Lei, Du; Zhao, Yuandi; Cheng, Tongsheng; Zeng, Shaoqun; Luo, Qingming

    2003-07-01

    The latest self-encoding resin bead is a novel technology for solid phase synthesis combinatorial library screening. A new encode-positional deconvolution strategy which was based on that technology been illustrated compared with positional scanning and iterative strategies. The self-encoding resin beads technology provides an efficient method for improving the high-throughput screening of combinatorial library.

  15. Screening of proteins binding to mouse cytomegalovirus M122 protein from mouse brain cDNA library by yeast two-hybrid system%酵母双杂交技术筛选小鼠脑cDNA文库中鼠巨细胞病毒即刻早期蛋白M122相互作用蛋白的研究

    Institute of Scientific and Technical Information of China (English)

    王慧; 周玉峰; 舒赛男; 罗丹; 田佳; 张慧娟; 杜小弋; 方峰

    2010-01-01

    histone acetyltransferase(monocytic leukemia)4,Myst4]、透明质酸和蛋白多糖连接蛋白1(hyaluronan and proteoglycan link protein 1,Hapln1)、自噬相关蛋白3(autophagy-related 3,Atg3)、精氨酸/色氨酸富集的剪切因子5(splicing factor,arginine/serine-rich 5,Sfrs5)、C3HC型锌指蛋白(zinc finger,C3HC-type containing 1,Zc3hc1)、硫氧还蛋白相关的跨膜蛋白1(thioredoxin-related transmembrane protein 1,Txndc1)、接头蛋白复合物AP-1亚单位(adaptor protein complex AP-1,gamma 1 subunit,Aplg1)和Cul1蛋白(cullin 1,Cul1).回返验证实验进一步证实这些蛋白与M122蛋白能够在酵母细胞AH109发生相互作用,但Aplg1和Cul1被证实具有自激活作用.结论 筛选到的其中19种已知基因编码的蛋白可能与巨细胞病毒的致病机制相关,但仍需进一步的验证.%Objective To investigate the biological function of M122 in pathogenesis of MCMV in developmental brain disorders and brain damage, screening for mouse brain cDNA library interacting with M122 was performed by a yeast two-hybrid system. Methods The reconstructed bait plasmid pGBKT7-M122 was transformed into yeast cells AH109 and screened on the nutrient deficiency medium SD/-Trp. After express of the bait protein in AH109 yeast strains was detected by Western blot analysis, yeast-two hybrid screening was performed by mating AH109 with Y187 containing mouse brain cDNA library plasmid. The diploid yeast cells were plated on the nutrient deficiency medium SD/-Trp/-Leu/-His/-Ade. The second screening was performed with SD/-Trp/-Leu/-His/-Ade containing X-α-gal. The plasmids in positive colonies were extracted and transformed into E. coli JM109 cells. After plasmid DNA in JM109 cells were extracted form positive colonies and sequenced, the results were analyzed by bioinformatic methods. The interactions between M122 protein and the protein obtained from positive colonies were further confirmed by repeating yeast-two hybrid. Then, autoactivations of

  16. Optimal screening of surface-displayed polypeptide libraries.

    Science.gov (United States)

    Boder, E T; Wittrup, K D

    1998-01-01

    Cell surface display of polypeptide libraries combined with flow cytometric cell sorting presents remarkable potential for enhancement of protein-ligand recognition properties. To maximize the utility of this approach, screening and purification conditions must be optimized to take full advantage of the quantitative feature of this technique. In particular, discrimination of improved library mutants from an excess of wild-type polypeptides is dependent upon an effective screening methodology. Fluorescence discrimination profiles for improved library mutants were derived from a mathematical model of expected cell fluorescence intensities for polypeptide libraries screened with fluorescent ligand. Profiles for surface-displayed libraries under equilibrium or kinetic screening conditions demonstrate distinct discrimination optima from which optimal equilibrium and kinetic screening parameters were derived. In addition, a statistical model of low cytometrically analyzed cell populations indicates the importance of low-stringency sorting followed by amplification through regrowth and resorting at increased stringency. This analysis further yields quantitative recommendations for cell-sorting stringency.

  17. Preparation of a subtractive cDNA library enriched in cDNAs which expressed at a high level in cultured senescent human fibroblasts.

    Science.gov (United States)

    Tahara, H; Hara, E; Tsuyama, N; Oda, K; Ide, T

    1994-03-30

    Subtracted cDNA library was prepared by subtracting [cDNA from young growing SV40-transformed human fibroblasts] from [cDNA from growing SV40-transformed fibroblasts in extended lifespan]. Isolated cDNA clones which expressed at high level in life-extended transformed cells also expressed at high level in normal senescent fibroblasts but did at low level in growing and growth-arrested young cells. Neither fibronectin nor procollagen cDNA was isolated. This cDNA library is useful for isolation of senescent-specific cDNA species which express at high level in normal senescent cells but at low level in growing and growth-arrested young cells, avoiding growth-arrest-specific cDNAs.

  18. Suppression subtractive hybridization: a method for generating differentially regulated or tissue-specific cDNA probes and libraries.

    OpenAIRE

    1996-01-01

    A new and highly effective method, termed suppression subtractive hybridization (SSH), has been developed for the generation of subtracted cDNA libraries. It is based primarily on a recently described technique called suppression PCR and combines normalization and subtraction in a single procedure. The normalization step equalizes the abundance of cDNAs within the target population and the subtraction step excludes the common sequences between the target and driver populations. In a model sys...

  19. Isolation of cDNAs of scrapie-modulated RNAs by subtractive hybridization of a cDNA library.

    OpenAIRE

    1988-01-01

    We have developed a subtractive cloning procedure based on the hybridization of single-stranded cDNA libraries constructed in pi H3M, a vector containing the phage M13 origin of replication. We have used this strategy to isolate three transcripts whose abundance is increased in scrapie-infected brain. DNA sequence analysis showed that they represent glial fibrillary acidic protein, metallothionein II, and the B chain of alpha-crystallin; the latter two may represent a response to stress.

  20. 中华蜜蜂工蜂 cDNA 文库的构建及ESTs 测序分析%Construction of cDNA libraries and ESTs sequencing of Apis cerana cerana workers

    Institute of Scientific and Technical Information of China (English)

    张卫星; 郗学鹏; 秦明; 王帅; 刘春蕾; 王红芳; 胥保华

    2016-01-01

    Objectives] To build a cDNA library to improve understanding of how honey bee workers respond to adverse conditions and analyze the quality of the resultant library. [Methods] A cDNA library of Apis cerana cerana was constructed using the SMART technique. [Results] The library’s capacity was 3.6×106 cfu/mL, the recombination rate was 97% and the average length of inserts was approximately 1 000 bp. 306 ESTs were generated by ESTs sequencing. Additionally, 234 non-repetitive sequences were formed, including 207 singletons and 27 contigs after initial assembly. Using Blastx to query, compare and annotate these sequences with those in GenBank, revealed that 141 sequences could be assigned putative functions because they were homologous to known genes. Other sequences had no obvious homology, which suggests there is potential for the discovery of new functional genes. [Conclusion] The construction of a cDNA library has important benefits for cloning, screening and gene function research in Apis cerana cerana.%【目的】为了解中华蜜蜂 Apis cerana cerana 工蜂的抗逆性,构建了中华蜜蜂工蜂的 cDNA 文库,并对文库质量进行分析。【方法】本研究利用 SMART 技术构建了中华蜜蜂工蜂的全长 cDNA 文库。【结果】文库库容为3.6×106 cfu/mL,文库重组率为97%,插入片段长度多数分布在1000 bp 左右。挑取 cDNA克隆进行 EST 测序,共进行了306个成功反应,软件拼接共得到234个单基因簇(Unigene),其中包括207个单拷贝(Singletons)序列及27个重叠群(Contigs)。使用 Blastx 将这些序列同 GenBank 等数据库进行查询、比对和注释,结果显示141条序列有相关同源性,其他序列没有明显的同源性,这也为我们发现新功能基因提供了可靠依据。【结论】此文库的构建在中华蜜蜂功能基因的分离、克隆、筛选以及基因功能研究等方面具有重要作用。

  1. Determination of a Screening Metric for High Diversity DNA Libraries.

    Science.gov (United States)

    Guido, Nicholas J; Handerson, Steven; Joseph, Elaine M; Leake, Devin; Kung, Li A

    2016-01-01

    The fields of antibody engineering, enzyme optimization and pathway construction rely increasingly on screening complex variant DNA libraries. These highly diverse libraries allow researchers to sample a maximized sequence space; and therefore, more rapidly identify proteins with significantly improved activity. The current state of the art in synthetic biology allows for libraries with billions of variants, pushing the limits of researchers' ability to qualify libraries for screening by measuring the traditional quality metrics of fidelity and diversity of variants. Instead, when screening variant libraries, researchers typically use a generic, and often insufficient, oversampling rate based on a common rule-of-thumb. We have developed methods to calculate a library-specific oversampling metric, based on fidelity, diversity, and representation of variants, which informs researchers, prior to screening the library, of the amount of oversampling required to ensure that the desired fraction of variant molecules will be sampled. To derive this oversampling metric, we developed a novel alignment tool to efficiently measure frequency counts of individual nucleotide variant positions using next-generation sequencing data. Next, we apply a method based on the "coupon collector" probability theory to construct a curve of upper bound estimates of the sampling size required for any desired variant coverage. The calculated oversampling metric will guide researchers to maximize their efficiency in using highly variant libraries.

  2. Rasmuson Library DVD Browser: Fun with Screen Scraping and Drupal

    Directory of Open Access Journals (Sweden)

    Mark Morlino

    2008-12-01

    Full Text Available The DVD Browser is a simple application that lets library patrons browse movie covers, titles, and reviews. It works by screen scraping the the Rasmuson Library catalog for DVD movies and dumps the data into a Drupal MySQL database. This paper describes the process of setting up the DVD Browser.

  3. Construction of a full-length cDNA library for Senecio scandens%千里光全长cDNA文库的构建及分析

    Institute of Scientific and Technical Information of China (English)

    平军娇; 张珍; 蔡振锋; 汤贤春; 钱刚

    2012-01-01

    metabolites. Conclusion SMART technology could be effectively applied to constructing the full-length cDNA library of S. Scandens. Our results indicate that the full-length cDNA library could be further applied to regulation of expression on identification of functional genome, screening of novel genes, and biosynthesis of metabolism genes in S. Scandens.

  4. Construction of cDNA library of the treated Changliver cell and quality analysis%常氏肝癌细胞cDNA文库的构建及质量分析

    Institute of Scientific and Technical Information of China (English)

    林俊堂; 王聪睿; 张会勇; 李玉昌; 徐存拴

    2004-01-01

    目的利用RNA转录5′末端转换机制(SMART)构建适合免疫筛选的经去分化培养基处理的常氏肝癌细胞cDNA文库.方法通过反转录PCR和长距离PCR获得常氏肝癌细胞的全长cDNA,然后利用SMART cDNA文库构建试剂盒建立经去分化培养基处理的常氏肝癌细胞cDNA文库.结果通过测定,高质量的包含常氏肝癌细胞全长cDNA的cDNA文库得到建立,扩增cDNA文库的滴度高达4.5 × 1010 pfu*ml-1,重组子内平均插入外源基因片段长度在200 bp到4000 bp之间,约1500 bp左右,并且此文库适合免疫筛选.结论结果显示所构建的经去分化培养基处理的常氏肝癌细胞cDNA文库具有很高的质量, 为进一步研究常氏肝癌细胞和筛选相关基因获得cDNA全长奠定了坚实的基础.%Objective To construct cDNA library of the treated Changliver cell by switching mechanism at 5′ end of RNA transcript (SMART) technique and analyze its quality.Methods cDNA of Changliver cell was aquired with reverse transcription polymerase chain reaction (RT-PCR) and long-distance PCR (LD-PCR),then the cDNA library was constructed with SMART cDNA library construction kit.Results Through testing,the high quality cDNA library containing full length cDNA of Changliver cell had been constructed.The titer of the amplified cDNA library was 4.5 × 1010 pfu*ml-1 and the average exogenous inserts of the recombinants was 1.5 kb.Conclusion These results suggest that the Changliver cell cDNA library has a high quality and lays a solid foundation for researching on Changliver cell and screening

  5. Generation and Analysis of Expressed Sequence Tags (ESTs) from Muscle Full-Length cDNA Library of Wujin Pig

    Institute of Scientific and Technical Information of China (English)

    ZHAO Su-mei; LIU Yong-gang; PAN Hong-bing; ZHANG Xi; GE Chang-rong; JIA Jun-jing; GAO Shi-zheng

    2014-01-01

    Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Construction of a full-length cDNA library is an effective way to understand the expression of functional genes in muscle tissues. In addition, novel genes for further research could be identiifed in the library. In this study, we constructed a full-length cDNA library from porcine muscle tissue. The estimated average size of the cDNA inserts was 1076 bp, and the cDNA fullness ratio was 86.2%. A total of 1058 unique sequences with 342 contigs (32.3%) and 716 singleton (67.7%) expressed sequence tags (EST) were obtained by clustering and assembling. Meanwhile, 826 (78.1%) ESTs were categorized as known genes, and 232 (21.9%) ESTs were categorized as unknown genes. 65 novel porcine genes that exhibit no identity in the TIGR gene index ofSus scrofa and 124 full-length sequences with unknown functions were deposited in the dbEST division of GenBank (accession numbers: EU650784-EU650788, GE843306, GH228978-GH229100). The abundantly expressed genes in porcine muscle tissue were related to muscle ifber development, energy metabolism and protein synthesis. Gene ontology analysis showed that sequences expressed in porcine muscle tissue contained a high percentage of binding activity, catalytic activity, structural molecule activity and motor activity, which involved mainly in metabolic, cellular and developmental process, distributed mainly in intracellular region. The sequence data generated in this study would provide valuable information for identifying porcine genes expressed in muscle tissue and help to advance the study on the structure and function of genes in pigs.

  6. Seek protein which can interact with hepatitis B virus X protein from human liver cDNA library by yeast two-hybrid system

    Institute of Scientific and Technical Information of China (English)

    Xiao-Zhong Wang; Xiang-Rong Jiang; Xiao-Chun Chen; Zhi-Xing Chen; Dan Li; Jian-Yin Lin; Qi-Min Tao

    2002-01-01

    AIM: To seek the X associated protein (XAP) with theconstructed bait vector pAS2-1X from normal human livercDNA library.METHODS: The X region of the HBV gene was amplied byPCR and cloned into the eukaryotic expression vector pAS2-l.The reconstituted plasmid pAS2-1X was transformed intothe yeast cells and the expression of X protein (pX) wasconfirmed by Western blot analysis. Yeast cells werecotransformed with pAS2-1X and the normal human livercDNA library and were grown in selective SC/-trp-leu-his-ade medium, the second screen was performed with theLacZ report gene. Furthermore, segregation analysis andmating experiment were performed to eliminate the falsepositive and the true positive clones were selected for PCRand sequencing.RESULTS: Reconstituted plasmid pAS2-1X including theanticipated fragment of X gene was proved by auto-sequencing assay. Western blot analysis showed thatreconstituted plasmid pAS2-1X expressed BD: X fusionprotein in yeast cells. Of 5 × 106 transformed coloniesscreened, 65 grew in the selective SC/-trp-leu-his-ademedium, 5 scored positive for β-gal activity, and only 2remaining clones passed through the segregation analysisand mating experiment. Sequence analysis identified thattwo clones contained similar cDNA fragment: GAACFFGCG.CONCLUSION: The short peptide (glutacid-leucine-alanine)is a possible required site for XAP binding to pX. Normalhuman liver cDNA library has difficulties in expressing theintegrated XAP on yeast cells.

  7. An anti-tumor protein produced by Trichinella spiralis and identified by screening a T7 phage display library, induces apoptosis in human hepatoma H7402 cells

    Science.gov (United States)

    Trichinella spiralis infection confers effective resistance to tumor cell expansion. In this study, a T7 phage cDNA display library was constructed to express genes encoded by T. spiralis. Organic phase multi-cell screening was used to sort through candidate proteins in a transfected human chronic m...

  8. Chum-RNA allows preparation of a high-quality cDNA library from a single-cell quantity of mRNA without PCR amplification

    OpenAIRE

    2008-01-01

    Linear RNA amplification using T7 RNA polymerase is useful in genome-wide analysis of gene expression using DNA microarrays, but exponential amplification using polymerase chain reaction (PCR) is still required for cDNA library preparation from single-cell quantities of RNA. We have designed a small RNA molecule called chum-RNA that has enabled us to prepare a single-cell cDNA library after four rounds of T7-based linear amplification, without using PCR amplification. Chum-RNA drove cDNA synt...

  9. Identification of a panel of tumor-associated antigens from breast carcinoma cell lines, solid tumors and testis cDNA libraries displayed on lambda phage

    Directory of Open Access Journals (Sweden)

    Cianfriglia Maurizio

    2004-11-01

    Full Text Available Abstract Background Tumor-associated antigens recognized by humoral effectors of the immune system are a very attractive target for human cancer diagnostics and therapy. Recent advances in molecular techniques have led to molecular definition of immunogenic tumor proteins based on their reactivity with autologous patient sera (SEREX. Methods Several high complexity phage-displayed cDNA libraries from breast carcinomas, human testis and breast carcinoma cell lines MCF-7, MDA-MB-468 were constructed. The cDNAs were expressed in the libraries as fusion to bacteriophage lambda protein D. Lambda-displayed libraries were efficiently screened with sera from patients with breast cancer. Results A panel of 21 clones representing 18 different antigens, including eight proteins of unknown function, was identified. Three of these antigens (T7-1, T11-3 and T11-9 were found to be overexpressed in tumors as compared to normal breast. A serological analysis of the 21 different antigens revealed a strong cancer-related profile for at least five clones (T6-2, T6-7, T7-1, T9-21 and T9-27. Conclusions Preliminary results indicate that patient serum reactivity against five of the antigens is associated with tumor disease. The novel T7-1 antigen, which is overexpressed in breast tumors and recognized specifically by breast cancer patient sera, is potentially useful in cancer diagnosis.

  10. Gene discovery in Eimeria tenella by immunoscreening cDNA expression libraries of sporozoites and schizonts with chicken intestinal antibodies.

    Science.gov (United States)

    Réfega, Susana; Girard-Misguich, Fabienne; Bourdieu, Christiane; Péry, Pierre; Labbé, Marie

    2003-04-01

    Specific antibodies were produced ex vivo from intestinal culture of Eimeria tenella infected chickens. The specificity of these intestinal antibodies was tested against different parasite stages. These antibodies were used to immunoscreen first generation schizont and sporozoite cDNA libraries permitting the identification of new E. tenella antigens. We obtained a total of 119 cDNA clones which were subjected to sequence analysis. The sequences coding for the proteins inducing local immune responses were compared with nucleotide or protein databases and with expressed sequence tags (ESTs) databases. We identified new Eimeria genes coding for heat shock proteins, a ribosomal protein, a pyruvate kinase and a pyridoxine kinase. Specific features of other sequences are discussed.

  11. An analysis of expressed sequence tags of developing castor endosperm using a full-length cDNA library

    Directory of Open Access Journals (Sweden)

    Wallis James G

    2007-07-01

    Full Text Available Abstract Background Castor seeds are a major source for ricinoleate, an important industrial raw material. Genomics studies of castor plant will provide critical information for understanding seed metabolism, for effectively engineering ricinoleate production in transgenic oilseeds, or for genetically improving castor plants by eliminating toxic and allergic proteins in seeds. Results Full-length cDNAs are useful resources in annotating genes and in providing functional analysis of genes and their products. We constructed a full-length cDNA library from developing castor endosperm, and obtained 4,720 ESTs from 5'-ends of the cDNA clones representing 1,908 unique sequences. The most abundant transcripts are genes encoding storage proteins, ricin, agglutinin and oleosins. Several other sequences are also very numerous, including two acidic triacylglycerol lipases, and the oleate hydroxylase (FAH12 gene that is responsible for ricinoleate biosynthesis. The role(s of the lipases in developing castor seeds are not clear, and co-expressing of a lipase and the FAH12 did not result in significant changes in hydroxy fatty acid accumulation in transgenic Arabidopsis seeds. Only one oleate desaturase (FAD2 gene was identified in our cDNA sequences. Sequence and functional analyses of the castor FAD2 were carried out since it had not been characterized previously. Overexpression of castor FAD2 in a FAH12-expressing Arabidopsis line resulted in decreased accumulation of hydroxy fatty acids in transgenic seeds. Conclusion Our results suggest that transcriptional regulation of FAD2 and FAH12 genes maybe one of the mechanisms that contribute to a high level of ricinoleate accumulation in castor endosperm. The full-length cDNA library will be used to search for additional genes that affect ricinoleate accumulation in seed oils. Our EST sequences will also be useful to annotate the castor genome, which whole sequence is being generated by shotgun sequencing at

  12. Achieving high throughput sequencing of a cDNA library utilizing an alternative protocol for the bench top next-generation sequencing system.

    Science.gov (United States)

    Wan, Minxi; Faruq, Junaid; Rosenberg, Julian N; Xia, Jinlan; Oyler, George A; Betenbaugh, Michael J

    2013-02-15

    The development of next-generation sequencing (NGS) technologies has provided novel tools for genome analysis and expression profiling. A high throughput cDNA sequencing method using a bench top next-generation sequencing system, GS Junior, is now available. Here, we used an alternative protocol to the standard method for generating the cDNA library. This protocol can decrease the number of processing steps to manipulate RNA when constructing a cDNA library from an RNA sample, and does not require mRNA isolation from total RNA. Thus it can decrease the risk of RNA degradation and the cost for preparing a cDNA library. Also, the efficiency of sequencing data obtained with this approach is comparable to the standard method as verified by sequencing characteristics and expression levels of the reference gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

  13. Construction of SMART cDNA Library of Sheep Ovary and Identification of Candidate Gene by Homologous Cloning

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The cDNA library of an ovary from Small Tail Han sheep before estrus was constructed by switching mechanism at 5' end of RNA transcript (SMART) approach. This library had a plaque titer of 1 × 109pfu mL-1 and a 96% recombinant ratio of which the fragment length of inserted average eDNA sequences was 1.0 kb. Based on bioinformatics analysis of the sequences, we obtained 338 expressed sequence tags (ESTs) from 380 cDNA clones which indicated 191 contigs. These contigs consist of 89 unmatched ESTs, 9 homologous known genes in sheep, and 93 homologous sequences in species of mouse, bovine, and human beings, including 19 sequences expressed in the ovary or follicle and 14 unknown sequences.Several candidate genes associated with sheep reproduction trait such as epidermal growth factor (EGF), estrogen receptor (ESR), Inhibin, follicle stimulating hormone receptor (FSHR), prostaglandin (PG), and transforming growth factor-β (TGF-β) were identified and the homologous were cloned from this library, which will contribute to compile expression profies and find the major genes of prolificacy of Small Tail Han sheep.

  14. Structure-Based Virtual Screening of Commercially Available Compound Libraries.

    Science.gov (United States)

    Kireev, Dmitri

    2016-01-01

    Virtual screening (VS) is an efficient hit-finding tool. Its distinctive strength is that it allows one to screen compound libraries that are not available in the lab. Moreover, structure-based (SB) VS also enables an understanding of how the hit compounds bind the protein target, thus laying ground work for the rational hit-to-lead progression. SBVS requires a very limited experimental effort and is particularly well suited for academic labs and small biotech companies that, unlike pharmaceutical companies, do not have physical access to quality small-molecule libraries. Here, we describe SBVS of commercial compound libraries for Mer kinase inhibitors. The screening protocol relies on the docking algorithm Glide complemented by a post-docking filter based on structural protein-ligand interaction fingerprints (SPLIF).

  15. Pattern analysis approach reveals restriction enzyme cutting abnormalities and other cDNA library construction artifacts using raw EST data

    Directory of Open Access Journals (Sweden)

    Zhou Sun

    2012-05-01

    Full Text Available Abstract Background Expressed Sequence Tag (EST sequences are widely used in applications such as genome annotation, gene discovery and gene expression studies. However, some of GenBank dbEST sequences have proven to be “unclean”. Identification of cDNA termini/ends and their structures in raw ESTs not only facilitates data quality control and accurate delineation of transcription ends, but also furthers our understanding of the potential sources of data abnormalities/errors present in the wet-lab procedures for cDNA library construction. Results After analyzing a total of 309,976 raw Pinus taeda ESTs, we uncovered many distinct variations of cDNA termini, some of which prove to be good indicators of wet-lab artifacts, and characterized each raw EST by its cDNA terminus structure patterns. In contrast to the expected patterns, many ESTs displayed complex and/or abnormal patterns that represent potential wet-lab errors such as: a failure of one or both of the restriction enzymes to cut the plasmid vector; a failure of the restriction enzymes to cut the vector at the correct positions; the insertion of two cDNA inserts into a single vector; the insertion of multiple and/or concatenated adapters/linkers; the presence of 3′-end terminal structures in designated 5′-end sequences or vice versa; and so on. With a close examination of these artifacts, many problematic ESTs that have been deposited into public databases by conventional bioinformatics pipelines or tools could be cleaned or filtered by our methodology. We developed a software tool for Abnormality Filtering and Sequence Trimming for ESTs (AFST, http://code.google.com/p/afst/ using a pattern analysis approach. To compare AFST with other pipelines that submitted ESTs into dbEST, we reprocessed 230,783 Pinus taeda and 38,709 Arachis hypogaea GenBank ESTs. We found 7.4% of Pinus taeda and 29.2% of Arachis hypogaea GenBank ESTs are “unclean” or abnormal, all of which could be cleaned

  16. Construct breast carcinoma T7 phage display cDNA library%乳腺癌T7噬菌体展示cDNA文库的构建

    Institute of Scientific and Technical Information of China (English)

    张涛; 施宝民; 王洪; 陈鹊汀; 季堃; 余松林

    2015-01-01

    目的 构建乳腺癌组织T7噬菌体展示cDNA文库,为下一步筛选差异蛋白打下基础.方法 利用乳腺癌新鲜标本,提取总RNA,分离mRNA并进行纯化,然后合成cDNA,连接体外包装获得T7噬菌体展示cDNA文库.结果 总RNA经检测,A260/A280=1.87,纯化的mRNA产量为4.0μg,A260/A280=1.91,合成的cDNA大小在200~6 000 bp之间,原始文库的容量为2×107pfu,文库重组率为90%,插入片段长度在300~2 000 bp之间.结论 噬菌体展示技术是进行蛋白质功能研究的高效方法,构建高质量的乳腺癌噬菌体展示cDNA文库,可用于肿瘤标志物的筛选、肿瘤疫苗的研制、多肽药物的开发、靶向治疗的研究等众多领域.%Objective To construct the breast carcinoma T7 phage display cDNA library,so the foundation for the screening of differentially expressed proteins was laid. Methods Firstly,fresh specimens of breast carcinoma was used to extract total RNA,separating and purifying of mRNA. Then synthesis cDNA was done. At last,the packaging was connected in vitro and T7 phage display cDNA library was obtained. Results The total RNA was tested,the result is A260/A280=1.87. The purified mRNA is 4.0μg,A260/A280=1.91. The size of cDNA is 200-6 000 bp. The primary library capacity is 2 × 107pfu. Recombination rate of the library is 90%. The length of inserted fragments is 300-2 000 bp. Conclusions Phage display is an efficient method of protein function research. We constructed a high quality breast cancer phage display cDNA Library. The library can be used for screening tumor markers,tumor vaccine,polypeptide drug development,targeted research,and so on.

  17. Efficient Management of High-Throughput Screening Libraries with SAVANAH

    DEFF Research Database (Denmark)

    List, Markus; Elnegaard, Marlene Pedersen; Schmidt, Steffen;

    2017-01-01

    High-throughput screening (HTS) has become an indispensable tool for the pharmaceutical industry and for biomedical research. A high degree of automation allows for experiments in the range of a few hundred up to several hundred thousand to be performed in close succession. The basis for such scr......High-throughput screening (HTS) has become an indispensable tool for the pharmaceutical industry and for biomedical research. A high degree of automation allows for experiments in the range of a few hundred up to several hundred thousand to be performed in close succession. The basis...... for such screens are molecular libraries, that is, microtiter plates with solubilized reagents such as siRNAs, shRNAs, miRNA inhibitors or mimics, and sgRNAs, or small compounds, that is, drugs. These reagents are typically condensed to provide enough material for covering several screens. Library plates thus need...

  18. 人胎儿骨骼和关节RACE cDNA文库的构建%The construction of rapid amplification of cDNA ends cDNA libraries from human fetal bone and joint

    Institute of Scientific and Technical Information of China (English)

    梁晓媛; 龚瑶琴; 刘奇迹; 李江夏; 陈丙玺; 郭辰虹

    2001-01-01

    目的 建立人胎儿骨骼和关节快速扩增cDNA末端(rapid amplification of cDNA ends,RACE cDNA)文库,为分离骨骼和关节发育相关基因奠定基础。方法 采用改进的异硫氰酸胍-酚-氯仿-异戊醇一步法提取骨骼和关节总RNA,用TaKaRa公司生产的cDNA合成试剂盒合成平末端的双链cDNA,然后与衔接子连接。再用位于双链cDNA末端的通用引物扩增全部cDNA。结果 建立了从骨骼和关节构建RACE cDNA文库的方法,并用该方法成功地构建了人胎儿骨骼和关节RACE cDNA文库。结论 所构建的的利用少量总RNA构建RACE cDNA文库方法切实可行,所构建的文库适用于用RACE方法从中分离骨骼和关节发育相关基因。%Objective To construct rapid amplification cDNA ends(RACE) cDNA libraries from human fetal bone and joint and provide resources for isolation of bone- and joint- specific development-related genes.Methods Total RNA of bone and joint were extracted with the modified single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. The double-stranded end-blunted cDNA were synthesized using TaKaRa's cDNA synthesis kit and ligated to cassette adaptors. All of the cDNA molecules were amplified by a pair of common primers.Results A protocol for RACE cDNA library construction from bone and joint was established and two RACE cDNA libraries from human fetal bone and joint were successfully constructed.Conclusion The protocol of RACE cDNA library construction from limited materials proved to be simple and efficient and the library was suitable for RACE to isolate tissue-specific genes.

  19. Construction of a full-length cDNA library of Solen grandis dunker and identification of defense- and immune-related genes

    Science.gov (United States)

    Sun, Guohua; Liu, Xiangquan; Ren, Lihua; Yang, Jianmin; Wei, Xiumei; Yang, Jialong

    2013-11-01

    The basic genetic characteristics, important functional genes, and entire transcriptome of Solen grandis Dunker were investigated by constructing a full-length cDNA library with the `switching mechanism at the 5'-end of the RNA transcript' (SMART) technique. Total RNA was isolated from the immune-relevant tissues, gills and hemocytes, using the Trizol reagent, and cDNA fragments were digested with Sfi I before being ligated to the pBluescript II SK* vector. The cDNA library had a titer of 1048 cfu μL-1 and a storage capacity of 1.05×106 cfu. Approximately 98% of the clones in the library were recombinants, and the fragment lengths of insert cDNA ranged from 0.8 kb to 3.0 kb. A total of 2038 expressed sequence tags were successfully sequenced and clustered into 965 unigenes. BLASTN analysis showed that 240 sequences were highly similar to the known genes (E-value 80%), accounting for 25% of the total unigenes. According to the Gene Ontology, these unigenes were related to several biological processes, including cell structure, signal transport, protein synthesis, transcription, energy metabolism, and immunity. Fifteen of the identified sequences were related to defense and immunity. The full-length cDNA sequence of HSC70 was obtained. The cDNA library of S. grandis provided a useful resource for future researches of functional genomics related to stress tolerance, immunity, and other physiological activities.

  20. Antibody Phage Library Screening Efficiency Measured by KD Values

    Institute of Scientific and Technical Information of China (English)

    WANG Hui-tang; SHAN Ya-ming; TANG Li-li; GAO Li-zeng; WANG Li-ping; LI Wei; LI Yu-xin

    2005-01-01

    An antibody phage library was screened with two target molecules, IFNα-2a and FGFR-GST, and the KD value of each round of panning was measured. It was found that the apparent KD values decreased along with each additional panning round, which indicates the increase of the binding affinity between the phage and the target molecules.This result shows that the KD value is a reliable intrinsic parameter and a new method for screening efficiency detection is thus provided.

  1. Rapid plasmid library screening using RecA-coated biotinylated probes.

    Science.gov (United States)

    Rigas, B; Welcher, A A; Ward, D C; Weissman, S M

    1986-12-01

    A method for the rapid physical isolation of recombinant plasmids of interest from a mixture of plasmids such as a plasmid cDNA library is presented. This method utilizes the ability of RecA protein to form stable complexes between linear single-stranded and circular double-stranded DNA molecules sharing sequence homology, and procedures allowing isolation of biotinylated nucleic acid. Biotinylated linear DNA probes coated with RecA have been used to screen reconstituted plasmid libraries consisting of two plasmid species, one homologous and the other heterologous to the probe. When the link between biotin and the nucleotide base could be cleaved by reducing agents, the complex was purified by streptavidin-agarose chromatography and the recovered plasmid was propagated in Escherichia coli. When the link was not cleavable the complex was bound to avidin in solution and purified by cupric iminodiacetic acid-agarose chromatography. The complex was then dissociated and the plasmids were propagated in E. coli. With either protocol, homologous plasmid recovery was between 10% and 20%, and enrichment was between 10(4)- and 10(5)-fold. Potential applications and extensions of this method, such as plasmid, cosmid, and phage library screening and facilitation of physical mapping of macroregions of mammalian genomes are presented and discussed.

  2. Analysis of expressed sequence tags generated from full-length enriched cDNA libraries of melon

    Directory of Open Access Journals (Sweden)

    Bendahmane Abdelhafid

    2011-05-01

    Full Text Available Abstract Background Melon (Cucumis melo, an economically important vegetable crop, belongs to the Cucurbitaceae family which includes several other important crops such as watermelon, cucumber, and pumpkin. It has served as a model system for sex determination and vascular biology studies. However, genomic resources currently available for melon are limited. Result We constructed eleven full-length enriched and four standard cDNA libraries from fruits, flowers, leaves, roots, cotyledons, and calluses of four different melon genotypes, and generated 71,577 and 22,179 ESTs from full-length enriched and standard cDNA libraries, respectively. These ESTs, together with ~35,000 ESTs available in public domains, were assembled into 24,444 unigenes, which were extensively annotated by comparing their sequences to different protein and functional domain databases, assigning them Gene Ontology (GO terms, and mapping them onto metabolic pathways. Comparative analysis of melon unigenes and other plant genomes revealed that 75% to 85% of melon unigenes had homologs in other dicot plants, while approximately 70% had homologs in monocot plants. The analysis also identified 6,972 gene families that were conserved across dicot and monocot plants, and 181, 1,192, and 220 gene families specific to fleshy fruit-bearing plants, the Cucurbitaceae family, and melon, respectively. Digital expression analysis identified a total of 175 tissue-specific genes, which provides a valuable gene sequence resource for future genomics and functional studies. Furthermore, we identified 4,068 simple sequence repeats (SSRs and 3,073 single nucleotide polymorphisms (SNPs in the melon EST collection. Finally, we obtained a total of 1,382 melon full-length transcripts through the analysis of full-length enriched cDNA clones that were sequenced from both ends. Analysis of these full-length transcripts indicated that sizes of melon 5' and 3' UTRs were similar to those of tomato, but

  3. Construction and Characterization of a cDNA Library from the Pulp of Coconut (Cocos nucifera L.)

    Institute of Scientific and Technical Information of China (English)

    LI Dong-dong; FAN Yong-mei

    2008-01-01

    To investigate the gene expression profile of endosperm development,a cDNA library was constructed and characterized from the pulp of coconut at different developmental stages.The constructed cDNA library incorporated approximately 1 × 107 clones in total,and the size of the insertion fragments ranged from 800 to 2000 bp.Sequencing results of 100 randomly picked clones showed that the recombination rate was 96%.In subsequent sequence analysis,41 clones (41%)were homologous to known function proteins,and 23 clones showed high amino acid identity (more than 80%) with the corresponding genes of different plants.Semi-quantitative RT-PCR indicated that oleosin and globulin genes are pulpspecific expression,and have differential expression level in different developmental stage.Clone 29,recognized as homologous to KIAA1239 protein (Homo sapiens),was observed to occur nine times,indicating that this gene may be over-expressed during the endosperm development stage.However,the homologous protein was found only in mammals,and the detailed function is still unknown.Elucidation of the functional characterization of these genes will be carried out immediately.

  4. Recovery of a soybean urease genomic clone by sequential library screening with two synthetic oligodeoxynucleotides.

    Science.gov (United States)

    Krueger, R W; Holland, M A; Chisholm, D; Polacco, J C

    1987-01-01

    We report the first isolation of a low-copy-number gene from a complex higher plant (soybean) genome by direct screening with synthetic oligodeoxynucleotide (oligo) probes. A synthetic, mixed, 21-nucleotide (nt) oligo (21-1) based on a seven amino acid (aa) sequence from soybean seed urease, was used to screen genomic libraries of soybean (Glycine max [L.] Merr.) in the lambda Charon 4 vector. Twenty homologous clones were recovered from a screen of 500,000 plaques. These were counterscreened with embryo-specific cDNA (15-2 cDNA) made by priming with a second, mixed 15-nt oligo (15-2), based on a Jack bean (Canavalia ensiformis) urease peptide [Takishima et al., J. Natl. Def. Med. Coll. 5 (1980) 19-23]. Five out of 20 clones were homologous to 15-2 cDNA and proved to be identical. Nucleotide sequence analysis of representative clone E15 confirmed that it contained urease sequences. Subclones of E15 homologous to the oligo probes contain a deduced amino acid sequence which matches 108 of 130 aa residues of an amino acid run in a recently published [Mamiya et al., Proc. Jap. Acad. 61B (1985) 359-398] complete protein sequence for Jack-bean seed urease. Using clone E15 as a probe of soybean embryonic mRNA revealed a homologous 3.8-kb species that is the size of the urease messenger. This species is absent from mRNA of embryos of a soybean seed urease-null mutant. However, both urease-positive and urease-null genomes contain the 11-kb DNA fragment bearing urease sequences.

  5. 微量RNA的cDNA PCR文库的构建%The Construction of cDNA PCR Library from a Small Amount of RNA

    Institute of Scientific and Technical Information of China (English)

    李晶泉; 袁晓东; 汤敏谦

    2001-01-01

    By the method of PCR (Polymerase Chain Reaction),we have constructed the cDNA PCR library from mRNA.The cDNA PCR library can amplify the original cDNA up to hundreds of times.With the total RNA of human K562 cultured cell,the cDNA of β-Actin has been obtained by the methods of cDNA PCR library and reverse transcription respectively.As contrast,the amount of β-Actin′s cDNA from the cDNA PCR library is much higher than from reverse transcription.75pg total RNA of human K562 Cultured cell is employed to construct 50μl cDNA PCR library,and the cDNA of β-Actin can even be detected by using 1μl of the library as template to perform the PCR.Therefore cDNA PCR library can greatly enlarge the amount of information.%使用PCR(polymerase chain reaction)技术,调制了mRNA的cDNA PCR文库,实验证明,cDNA PCR文库能使原cDNA的量放大数百倍。同时,使用人体K562培养细胞的总RNA,对cDNA PCR文库法和反转录中的β-Actin的cDNA量进行了比较,cDNA PCR文库法中的β-Actin的cDNA量大大高于反转录中的β-Actin的cDNA量。使用75pg的人体K562培养细胞的总RNA,调制成50μl的cDNA PCR文库,使用1μl的cDNA PCR文库进行PCR反应时,可对文库中的β-Actin的cDNA进行PCR检测。因此,cDNA PCR文库显示了良好的信息放大性能。

  6. Generation of high-affinity fully human anti-interleukin-8 antibodies from its cDNA by two-hybrid screening and affinity maturation in yeast.

    Science.gov (United States)

    Ding, Ling; Azam, Mark; Lin, Yu-Huei; Sheridan, James; Wei, Shuanghong; Gupta, Gigi; Singh, Rakesh K; Pauling, Michelle H; Chu, Waihei; Tran, Antares; Yu, Nai-Xuan; Hu, Jiefeng; Wang, Wei; Long, Hao; Xiang, Dong; Zhu, Li; Hua, Shao-Bing

    2010-10-01

    We have developed a technology for rapidly generating novel and fully human antibodies by simply using the antigen DNA. A human single-chain variable fragment (scFv) antibody library was constructed in a yeast two-hybrid vector with high complexity. After cloning cDNA encoding the mature sequence of human interleukin-8 (hIL8) into the yeast two-hybrid system vector, we have screened the human scFv antibody library and obtained three distinct scFv clones that could specifically bind to hIL8. One clone was chosen for further improvement by a novel affinity maturation process using the error-prone PCR of the scFv sequence followed by additional rounds of yeast two-hybrid screening. The scFv antibodies of both primary and affinity-matured scFv clones were expressed in E. coli. All purified scFvs showed specific binding to hIL8 in reciprocal coimmunoprecipitation and ELISA assays. All scFvs, as well as a fully human IgG antibody converted from one of the scFv clones and expressed in the mammalian cells, were able to effectively inhibit hIL8 in neutrophil chemotaxis assays. The technology described can generate fully human antibodies with high efficiency and low cost.

  7. Insight into screening immunoglobulin gene combinatorial libraries in a phage display vector: a tale of two antibodies.

    Science.gov (United States)

    Kakinuma, A; Portolano, S; Chazenbalk, G; Rapoport, B; McLachlan, S M

    1997-01-01

    Combinatorial libraries of immunoglobulin genes in "phage display" vectors are a powerful tool for obtaining antigen-specific antibody fragments. To date, this approach has been used to isolate abundant, but not rare, human autoantibodies of IgG class. We have compared the relative efficiencies of panning pComb3 libraries made from intrathyroidal plasma cells for abundant human autoantibodies to thyroid peroxidase (TPO) and rare autoantibodies to the thyrotropin receptor (TSHR). TPO-specific Fab were readily obtained from a library using three different forms of recombinant antigen, (i) purified TPO, (ii) impure TPO in culture medium and, (iii) TPO expressed on the surface of CHO cells. In contrast, TSHR-specific Fab were not isolated. This was the case despite repeated pannings of six libraries from three optimal patients (IgG/kappa and IgG/lambda libraries for each patient). Both purified recombinant TSHR and CHO cells expressing TSHR on their surface were used. Library enrichment was observed on some screenings. However, Fab expressed by individual clones or from enriched libraries were not specific as determined by (i) binding to purified, radio-labeled antigen, (ii) FACS analysis of TSHR on intact CHO cells and, (iii) inhibition of radiolabeled TSH binding. Remarkably, in screening for both TPO- and TSHR-specific Fab, neither library enrichment nor the retention of cDNA inserts of the correct size correlated with obtaining Fab with the antigenic specificity sought. Indeed, excellent enrichment could be observed with conditioned medium from untransfected cells. Our data suggest that the key to isolating rare antibodies from phage display libraries is not the creation of vast libraries of greater diversity or even the development of more stable vectors. Rather, success in this endeavor appears to require reducing the "noise" of non-specific clones in a moderately sized library.

  8. An annotated cDNA library of juvenile Euprymna scolopes with and without colonization by the symbiont Vibrio fischeri

    Directory of Open Access Journals (Sweden)

    Tong Deyan

    2006-06-01

    Full Text Available Abstract Background Biologists are becoming increasingly aware that the interaction of animals, including humans, with their coevolved bacterial partners is essential for health. This growing awareness has been a driving force for the development of models for the study of beneficial animal-bacterial interactions. In the squid-vibrio model, symbiotic Vibrio fischeri induce dramatic developmental changes in the light organ of host Euprymna scolopes over the first hours to days of their partnership. We report here the creation of a juvenile light-organ specific EST database. Results We generated eleven cDNA libraries from the light organ of E. scolopes at developmentally significant time points with and without colonization by V. fischeri. Single pass 3' sequencing efforts generated 42,564 expressed sequence tags (ESTs of which 35,421 passed our quality criteria and were then clustered via the UIcluster program into 13,962 nonredundant sequences. The cDNA clones representing these nonredundant sequences were sequenced from the 5' end of the vector and 58% of these resulting sequences overlapped significantly with the associated 3' sequence to generate 8,067 contigs with an average sequence length of 1,065 bp. All sequences were annotated with BLASTX (E-value Conclusion Both the number of ESTs generated from each library and GO categorizations are reflective of the activity state of the light organ during these early stages of symbiosis. Future analyses of the sequences identified in these libraries promise to provide valuable information not only about pathways involved in colonization and early development of the squid light organ, but also about pathways conserved in response to bacterial colonization across the animal kingdom.

  9. Screening metagenomic libraries for laccase activities.

    Science.gov (United States)

    Ferrer, Manuel; Beloqui, Ana; Golyshin, Peter N

    2010-01-01

    Laccases are multi-copper oxidoreductases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) able to oxidise a wide variety of phenolic and non-phenolic compounds. They are useful enzymes for a variety of applications, including bioremediation and craft pulp bio-bleaching as the most significant ones. There is a considerable interest to find new laccases through the exploration of biological diversity. Laccases have been found in plants, insects, and bacteria but predominantly in fungi: these enzymes have been documented in about 60 fungal strains. Microbial diversity constitutes a largely unexplored treasure chest with new laccases with a good potential for basic science and biotechnology. At present, due to our inability to cultivate most microbes, the only means of accessing the resources of the microbial world is to harvest genetic resources ("metagenomes"), which can further on be subjected to extensive screening programs. In this chapter, we provide an overview of screening methods to identify laccase-encoding genes from environmental resources.

  10. [Cold induced cDNA library construction of highland barley (Hordeum vulgare L. var. nudum Hk. f.) using suppression subtractive hybridization technology].

    Science.gov (United States)

    He, Tao; Jia, Jing Fen

    2008-12-01

    Cold-induced genes of highland barley (Hordeum vulgare L. var. nudum Hk. f.) were studied using suppression subtractive hybridization (SSH) technique. The cDNA from the materials treated with 4 degrees C was used as "tester", and that from the materials growing in green house (20+/-2 degrees C) as "driver". A subtractive library of highland barley including 640 cDNA clones was constructed in this study. Enzyme digestion of 32 clones chosen randomly from the library indicated that 87.5% of them contained inserts. The cDNA inserts of 16 clones were sequenced. Blast search analyses showed that these cDNAs were homologies to genes encoding the following proteins: metallothionein, protein kinase, ethylene signal transcription factor, bZIP transcription factor, zing finger transcription factor, ribulose-1,5-bisphosphate carboxylase, ribosomal protein, sodium: hydrogen antiporter, catalase, NADPH-cytochrome reductase, ascorbate peroxidase, DNA binding protein, and sugar transporter-like protein. These results indicated that the cDNA clones in the library were related to cold-induced genes, and suggested that the cold-tolerant mechanism of highland barley might be a complicated, interactive system involving multiple approaches and genes. Construction of subtractive cDNA library provided an advantage for further studies to isolate and clone cold-induced genes in highland barley.

  11. Generation and analysis of expressed sequence tags from a cDNA library of the fruiting body of Ganoderma lucidum

    Directory of Open Access Journals (Sweden)

    Li Xiwen

    2010-03-01

    Full Text Available Abstract Background Little genomic or trancriptomic information on Ganoderma lucidum (Lingzhi is known. This study aims to discover the transcripts involved in secondary metabolite biosynthesis and developmental regulation of G. lucidum using an expressed sequence tag (EST library. Methods A cDNA library was constructed from the G. lucidum fruiting body. Its high-quality ESTs were assembled into unique sequences with contigs and singletons. The unique sequences were annotated according to sequence similarities to genes or proteins available in public databases. The detection of simple sequence repeats (SSRs was preformed by online analysis. Results A total of 1,023 clones were randomly selected from the G. lucidum library and sequenced, yielding 879 high-quality ESTs. These ESTs showed similarities to a diverse range of genes. The sequences encoding squalene epoxidase (SE and farnesyl-diphosphate synthase (FPS were identified in this EST collection. Several candidate genes, such as hydrophobin, MOB2, profilin and PHO84 were detected for the first time in G. lucidum. Thirteen (13 potential SSR-motif microsatellite loci were also identified. Conclusion The present study demonstrates a successful application of EST analysis in the discovery of transcripts involved in the secondary metabolite biosynthesis and the developmental regulation of G. lucidum.

  12. Computer selection of oligonucleotide probes from amino acid sequences for use in gene library screening.

    Science.gov (United States)

    Yang, J H; Ye, J H; Wallace, D C

    1984-01-11

    We present a computer program, FINPROBE, which utilizes known amino acid sequence data to deduce minimum redundancy oligonucleotide probes for use in screening cDNA or genomic libraries or in primer extension. The user enters the amino acid sequence of interest, the desired probe length, the number of probes sought, and the constraints on oligonucleotide synthesis. The computer generates a table of possible probes listed in increasing order of redundancy and provides the location of each probe in the protein and mRNA coding sequence. Activation of a next function provides the amino acid and mRNA sequences of each probe of interest as well as the complementary sequence and the minimum dissociation temperature of the probe. A final routine prints out the amino acid sequence of the protein in parallel with the mRNA sequence listing all possible codons for each amino acid.

  13. Construction and preliminary analysis of a normalized cDNA library from Locusta migratoria manilensis topically infected with Metarhizium anisopliae var. acridum.

    Science.gov (United States)

    Wang, Jie; Xia, Yuxian

    2010-08-01

    The insect immune response to fungal infection is poorly understood at the molecular level. To explore the molecular basis of this process, a novel method to analyze the gene transcripts of insects in response to pathogenic fungus was established. A normalized cDNA library based on the SMART method combined with DSN (duplex-specific nuclease) treatment was constructed using mRNA extracted from the fat body and hemocytes of Locusta migratoria manilensis 6-24h after being topically infected with Metarhizium anisopliae var. acridum. Analysis of 259 unigenes out of 303 sequenced inserts from the cDNA library revealed that the cDNA library was not contaminated with M. anisopliae transcripts and validated the presence of the immune-related genes characterized here. These results suggest that this method overcame the difficulties of contamination from a fungal source in constructing the host cDNA library from mycosed insects and proved that this method is reliable and feasible for investigation of host genes in response to fungal infection. Further studies of the expressed sequence tags from this library will provide insights into the molecular basis of insect immune response to fungal infection.

  14. Two-dimensional screening of the Wageningen chicken BAC library.

    Science.gov (United States)

    Crooijmans, R P; Vrebalov, J; Dijkhof, R J; van der Poel, J J; Groenen, M A

    2000-05-01

    We have constructed a Bacterial Artificial Chromosome (BAC) library that provides 5.5-fold redundant coverage of the chicken genome. The library was made by cloning partial HindIII-digested high-molecular-weight (HMW) DNA of a female White Leghorn chicken into the HindIII site of the vector pECBAC1. Several modifications of standard protocols were necessary to clone efficiently large partial HindIII DNA fragments. The library consists of 49,920 clones arranged in 130 384-well plates. An average insert size of 134 kb was estimated from the analysis of 152 randomly selected BAC clones. The average number of NotI restriction sites per clone was 0.77. After individual growth, DNA was isolated of the pooled clones of each 384-well plate, and subsequently DNA of each plate was isolated from the individual row and column pools. Screening of the Wageningen chicken BAC library was performed by two-dimensional PCR with 125 microsatellite markers. For 124 markers at least one BAC clone was obtained. FISH experiments of 108 BAC clones revealed chimerism in less than 1%. The number of different BAC clones per marker present in the BAC library was examined for 35 markers which resulted in a total of 167 different BAC clones. Per marker the number of BAC clones varied from 1 to 11, with an average of 4.77. The chicken BAC library constitutes an invaluable tool for positional cloning and for comparative mapping studies.

  15. In-depth cDNA Library Sequencing Provides Quantitative Gene Expression Profiling in Cancer Biomarker Discovery

    Institute of Scientific and Technical Information of China (English)

    Wanling Yang; Dingge Ying; Yu-Lung Lau

    2009-01-01

    procedures may allow detection of many expres-sion features for less abundant gene variants. With the reduction of sequencing cost and the emerging of new generation sequencing technology, in-depth sequencing of cDNA pools or libraries may represent a better and powerful tool in gene expression profiling and cancer biomarker detection. We also propose using sequence-specific subtraction to remove hundreds of the most abundant housekeeping genes to in-crease sequencing depth without affecting relative expression ratio of other genes, as transcripts from as few as 300 most abundantly expressed genes constitute about 20% of the total transcriptome. In-depth sequencing also represents a unique ad-vantage of detecting unknown forms of transcripts, such as alternative splicing variants, fusion genes, and regulatory RNAs, as well as detecting mutations and polymorphisms that may play important roles in disease pathogenesis.

  16. Applications of chemogenomic library screening in drug discovery.

    Science.gov (United States)

    Jones, Lyn H; Bunnage, Mark E

    2017-01-20

    The allure of phenotypic screening, combined with the industry preference for target-based approaches, has prompted the development of innovative chemical biology technologies that facilitate the identification of new therapeutic targets for accelerated drug discovery. A chemogenomic library is a collection of selective small-molecule pharmacological agents, and a hit from such a set in a phenotypic screen suggests that the annotated target or targets of that pharmacological agent may be involved in perturbing the observable phenotype. In this Review, we describe opportunities for chemogenomic screening to considerably expedite the conversion of phenotypic screening projects into target-based drug discovery approaches. Other applications are explored, including drug repositioning, predictive toxicology and the discovery of novel pharmacological modalities.

  17. Application of an improved cDNA competition technique to identify prostate cancer-associated gene.

    Science.gov (United States)

    Rinaldy, A R; Steiner, M S

    1999-11-01

    A technique to improve cDNA library screening was developed by using mixed probes derived from two closely related cDNA populations of high-metastatic MAT-LyLu and low-metastatic AT-1 Dunning R3227 rat prostate cancer sublines. The technique required the generation of a cDNA library from each subline followed by polymerase chain reaction (PCR) amplification of the cDNA insert population. The PCR products derived from the first library were radiolabeled and mixed with an excess amount of PCR products from the second library. The mixture and an excess amount of both the lambda and pBluescript DNA were used as a probe to screen the first cDNA library. This mixed probe (designated the competition probe) differentially cross-hybridized with the plaque lift of the screened first cDNA library. Weak radioactive signals indicated the cross-hybridization of cDNA sequences common to the competition probe mixture and the first cDNA library, whereas strong signals implied unhybridized unique or abundant cDNA sequences in the first cDNA library. The reproducibility of this technique was confirmed by showing that the full-length cDNA clones were associated with the phenotype of the screened first cell line. The isolated clones were characterized as rat nucleolar protein, rat mitochondrial genes coding for 16S and 12S rRNAs, and rat tRNAs specific for valine and phenyl-alanine. This result is consistent with the fact that the first cell line, MAT-LyLu, is metabolically more active than are AT-1 cells because of higher gene dosage or amplification of nucleolar and mitochondrial RNA and its associated genes. Another clone which had a strong signal represented a novel gene associated with the MAT-LyLu cancer phenotype.

  18. Construction and evaluation of yeast two-hybrid cDNA library of Diaphorina citri (Hemiptera: Psyllidae)%柑橘木虱酵母双杂交cDNA文库的构建及评价

    Institute of Scientific and Technical Information of China (English)

    马晓芳; 陈国庆; 张学潮; 徐海君

    2013-01-01

    In order to study the interacting proteins between the Asian citrus psyllid ( Diaphorina citri) and Candidatus Liberibacter asiaticus ( CLas) which is the pathogenic bacterium causing Huanglongbing, yeast two-hybrid cDNA library of D. citri was constructed using the Switching Mechanism at 5' End of the RNA Transcript (SMART) technique. The total RNA was isolated from the citrus psyllid adults bred in the laboratory and subjected to reverse transcription, and the double-strand cDNAs ( ds cDNAs) were synthesized. The ds cDNAs were ligated with homologous adapter and purified by the chromatography column. By using homologous recombination reaction, the ds cDNAs were transformed into the Y187 competent cell with the library plasmid pGADT7-Rec to construct yeast two-hybrid cDNA library. Detection of the library indicated that it contained more than 106 independent clones, the titer of the amplified library was 2. 23 × 10 cfu/mL, and the average size of inserts was above 750 bp in the cDNA library. These results demonstrate that the library meets the requirements of the standard cDNA library. Moreover, two membrane proteins, ORF420 and ORF3420, from ( CLas) were used as bait proteins to screen the interacting proteins in the library, but no positive clone was screened in the tests. The yeast two-hybrid cDNA library of D. citri will be useful for the research on the interaction between insect vectors and C. Liberibacter asiaticus in the future.%为了探索研究柑橘木虱Diaphorina citri与柑橘黄龙病(Huanglongbing,HLB)病原菌的相互作用蛋白,本研究运用RNA转录中5 '末端转换机制(Switching Mechanism at 5'End of the RNA Transcript,SMART)技术构建了柑橘木虱的酵母双杂交cDNA文库.以实验室饲养的柑橘木虱为材料,提取总RNA,经反转录后合成ds cDNA,两端添加同源重组序列,并用层析柱纯化;ds cDNA与文库质粒pGADT7-Rec在酵母Y187感受态细胞内发生同源重组,柑橘木虱cDNA重组到文库质粒

  19. Construction and characterization of a full-length cDNA library for the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici

    Directory of Open Access Journals (Sweden)

    Chen Xianming

    2007-06-01

    Full Text Available Abstract Background Puccinia striiformis is a plant pathogenic fungus causing stripe rust, one of the most important diseases on cereal crops and grasses worldwide. However, little is know about its genome and genes involved in the biology and pathogenicity of the pathogen. We initiated the functional genomic research of the fungus by constructing a full-length cDNA and determined functions of the first group of genes by sequence comparison of cDNA clones to genes reported in other fungi. Results A full-length cDNA library, consisting of 42,240 clones with an average cDNA insert of 1.9 kb, was constructed using urediniospores of race PST-78 of P. striiformis f. sp. tritici. From 196 sequenced cDNA clones, we determined functions of 73 clones (37.2%. In addition, 36 clones (18.4% had significant homology to hypothetical proteins, 37 clones (18.9% had some homology to genes in other fungi, and the remaining 50 clones (25.5% did not produce any hits. From the 73 clones with functions, we identified 51 different genes encoding protein products that are involved in amino acid metabolism, cell defense, cell cycle, cell signaling, cell structure and growth, energy cycle, lipid and nucleotide metabolism, protein modification, ribosomal protein complex, sugar metabolism, transcription factor, transport metabolism, and virulence/infection. Conclusion The full-length cDNA library is useful in identifying functional genes of P. striiformis.

  20. Substrate-induced gene expression screening: a method for high-throughput screening of metagenome libraries.

    Science.gov (United States)

    Uchiyama, Taku; Miyazaki, Kentaro

    2010-01-01

    The SIGEX (substrate-induced gene expression) method is a novel approach for the screening of gene (genome) libraries. In addition to the commonly used function- and sequence-driven approaches to screening, SIGEX provides a third option; in SIGEX, positives are identified using a reporter gene, and the library is constructed using an "operon-trap" vector. This vector contains the reporter gene immediately downstream of the cloning site for the genomic insert so that the expression of the inserted gene(s) is coupled with that of the reporter gene. This system is especially suitable for screening catabolic genes that are induced in response to metabolically relevant compounds, such as substrates. If expression of the inserted gene(s) is activated in response to the addition of these compounds, then positive clones can be identified based on the reporter signal. The most effective selection is obtained by the use of a FACS (fluorescence-activated cell sorter) in conjunction with a FACS-compatible fluorescent reporter protein, such as GFP (green fluorescent protein). Activity-based screening of metagenomic libraries often suffers from low sensitivity and low throughput. In contrast, the high throughput, high sensitivity, and versatility of SIGEX make it a particularly suitable method for screening metagenomic libraries.

  1. [Construction of suppression subtractive hybridization (SSH) library of copepod Pseudodiaptomous annandalei and its ferritin cDNA cloning and differential expression under nickel stress].

    Science.gov (United States)

    Jiang, Jie-Lan; Wang, Gui-Zhong; Wu, Li-Sheng; Li, Shao-Jing

    2012-07-01

    To study the molecular response mechanisms of copepod to nickel stress, a suppression subtractive hybridization (SSH) cDNA library of Pseudodiaptomous annandalei under nickel stress was constructed by using SSH technique, and a total of 140 clones were randomly picked from the growing colonies and identified by PCR. The recombinant rate of the library was 98.6%, and the volume of the library was 1.12 x 10(6) cfu. After the recombinant plasmids were sequenced, a partial cDNA fragment of ferritin was recognized based on BLAST searches in NCBI, with a size of 859 bp and continuously encoding 170 amino acid residues. The semi-quantitative PCR results showed that the ferritin cDNA under 24 h nickel stress was distinctly up-regulated. The successful construction of the SSH library and the obtaining of ferritin cDNA fragment would supply basis for the further study of the molecular response mechanisms of copepod to nickel stress.

  2. Construction of Geobacillus thermoglucosidasius cDNA library and analysis of genes expressed in response to heat stress.

    Science.gov (United States)

    Tripathy, S; Maiti, N K

    2014-03-01

    Thermophiles exhibit various kinds of molecular mechanisms to survive in extreme environment, but their behavioral responses to long duration stress is poorly understood until date. In the present study, we have prospected for the genes differentially expressed in response to long duration heat stress in thermophilic bacteria. A cDNA library was constructed from Geobacillus thermoglucosidasius grown with a temperature upshift of 10 °C from optimum growth temperature of 45 °C for 16 h. A total of 451 clones from the library were sequenced with accurate base calling that generated 257 high quality sequences with an average read length of 350 bp. We queried our collection of single pass sequences against the NCBI non-redundant database using the BLASTX algorithm and obtained sequences that showed significant similarity (>60%) with heat shock proteins, metabolic proteins and hypothetical proteins. The expressed sequence tags (ESTs) expressed in response to heat stress were annotated that further commuted a strong interaction network among one another. The ESTs based on the best hits were validated by RT-PCR. Di- and tri-nucleotide repeat motifs were also found to be associated with 17 genes involved in heat shock response, metabolism, transport and transcriptional regulation. The present results provide the novel identification of the putative genes responsible for imparting tolerance to bacteria under heat stress and unveil their role for survival of life in environmental extremes.

  3. Construction and Characterization of a cDNA Library from the Pulp of Cara Cara Navel Orange (Citrus sinensis Osbeck)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A cDNA library was constructed and characterized from the pulp of Cara Cara navel orange (Citrus sinensis Osbeck) at different stages of ripening. Tittering results revealed that approximately 5.086x105 independent clones were included in this library. Electrophoresis gel results of 15 randomly selected clones revealed that the size of the insertion fragments ranged from 400 bp to 2 kb, with an average size of 900 bp. Sequencing results of 150 randomly picked clones showed that the recombination rate was 94%. During subsequent sequence analysis, 41 of 139 clones failed to be identified and the amino sequence of 71 clones shared less than 30% identity with related plants in GenBank. Of 27 clones whose amino sequences shared more than 60% identity with other related plants in GenBank, 17 clones showed an 80% identity with the corresponding candidate genes of citrus. The clone recognized as the type Ⅲ metallothionein-like (MT) gene was observed to occur 13 times, indicating that the protein may play an important role in fruit development and ripening.

  4. Construction of a cDNA library for sea cucumber Acaudina leucoprocta and differential expression of ferritin peptide

    Science.gov (United States)

    Zhou, Jun; Hou, Fujing; Li, Ye; Su, Xiurong; Li, Taiwu; Jin, Chunhua

    2016-07-01

    Acaudina leucoprocta is an edible sea cucumber of economic interest that is widely distributed in China. Little information is available concerning the molecular genetics of this species although such knowledge would contribute to a better understanding of the optimal conditions for its aquaculture and its mechanisms of defense against disease. Therefore, we constructed a cDNA library and, based on bioinformatics analysis of the sequences, the functions of 75% of the cDNAs were identified, including those involved in cell structure, energy metabolism, mitochondrial function, and signal transduction pathways. Approximately 25% of genes in the library were unmatched. The gene for A. leucoprocta ferritin was also cloned. The predicted amino-acid sequence of ferritin displayed significant homology with other sea-cucumber counterparts but indicated that it was a new member of the ferritin family. Semiquantitative real-time RT-PCR indicated the highest levels of ferritin mRNA expression in the intestine. A polyclonal antibody of ferritin was also produced. These data provide a set of molecular tools essential for further studies of the functions of ferritin protein in A. leucoprocta.

  5. Construction and analysis of a subtractive cDNA library of early embryonic development in duck.

    Science.gov (United States)

    Liu, Y L; Zhong, L X; Li, J J; Shen, J D; Wang, D Q; Tao, Z R; Shi, F X; Lu, L Z

    2013-07-08

    Several studies have documented the process of early embryonic development in poultry; however, the molecular mechanisms underlying its developmental regulation are poorly understood, particularly in ducks. In this study, we analyzed differential gene expression of embryos 6 and 25 h following oviposition to determine which genes regulate the early developmental stage in ducks. Among 216 randomly selected clones, 39 protein-encoding cDNAs that function in metabolism, transcription, transportation, proliferation/apoptosis, cell cycle, cell adhesion, and methylation were identified. Additionally, the full-length cDNA of the Nanog gene, encoding a 302-amino acid protein, was obtained. Quantitative real-time polymerase chain reaction analyses were performed to detect expression levels of the selected genes during early and late embryonic stages, which revealed that these genes are expressed in a particular spatial and temporal pattern. These results indicate that these genes may play pivotal roles in the process of area pellucida formation through a complex and precise regulatory network during development in duck embryos.

  6. Rapid construction of directional cDNA library from human nasopharynx%鼻咽上皮组织定向cDNA文库的快速构建

    Institute of Scientific and Technical Information of China (English)

    张必成; 余鹰; 邱元正; 钱骏; 周鸣; 李忠花; 张小慧; 向娟娟; 朱诗国; 李桂源

    2001-01-01

    Objective To construct a directional cDNA library from human adult nasopharynx by SMART (switching mechanism at 5′ end of RNA transcript) technique. Methods The total RNA was separated from human adult nasopharynx epithelial fissue and the frist-strand cDNA was synthesized through reverse transcription by a modified oligo(dT) primer(contained sfi IB site) while the SMART oligonudeotide(contained sfi IA site) was utilized as a template so that the frist-strand cDNA could be extended over the 5′end of mRNA. The double-strand cDNA was amplified by LD-PCR(long-distance PCR) with the above two primers and then digested by sfi I (IA & IB) restriction enzyme.After cDNA size fractionation through CHROMA SPIN column,the double-strand cDNA was ligated into the sfi I-digested λTripIEx2 vector and then the recombinant DNA was packaged in vitro. Results The unamplified human adult nasopharynx cDNA library consists of 1.5×106 independent clones in which the percentage of recombinant clones is about 100%.The titer of the amplified cDNA library is 3.8×109 pfu/ml and the average exogenous inserts of the recombinants is 1.5 kb. Conclusion These results shows that the human adult nasopharynx cDNA library has an excellent quality and lays solid foundation for screening and cloning new tumor suppressor genes of nasopharyngeal carcinoma(NPC) and tissue-specific genes of human nasopharynx.%目的采用SMART (switching mechanism at 5′ end of RNA transcript)技术,快速构建了高质量的成人鼻咽上皮组织定向cDNA文库。方法从成人正常鼻咽上皮组织分离总RNA,利用经修饰的oligo(dT)引物(含sfi IB酶切位点)合成cDNA第一链,同时根据真核生物mRNA 5′端帽子结构特点,利用SMART核苷酸(含sfi IA酶切位点)作为cDNA第二链在mRNA 5′端延伸出去的模板,进而以此序列为引物利用LD-PCR(Long-distance-PCR)合成双链cDNA,双链cDNA经sfi I(IA & IB)酶切和过柱分

  7. Yeast surface display for antibody isolation: library construction, library screening, and affinity maturation.

    Science.gov (United States)

    Van Deventer, James A; Wittrup, Karl Dane

    2014-01-01

    Antibodies play key roles as reagents, diagnostics, and therapeutics in numerous biological and biomedical research settings. Although many antibodies are commercially available, oftentimes, specific applications require the development of antibodies with customized properties. Yeast surface display is a robust, versatile, and quantitative method for generating these antibodies and is accessible to single-investigator laboratories. This protocol details the key aspects of yeast surface display library construction and screening.

  8. RAPD-based screening of genomic libraries for positional cloning.

    Science.gov (United States)

    Dioh, W; Tharreau, D; Lebrun, M H

    1997-12-15

    RAPD markers are frequently used for positional cloning. However, RAPD markers often contain repeated sequences which prevent genomic library screening by hybridisation. We have developed a simple RAPD analysis of genomic libraries based on the identification of cosmid pools and clones amplifying the RAPD marker of interest. Our method does not require the cloning or characterisation of the RAPD marker as it relies on the analysis of cosmid pools or clones using a simple RAPD protocol. We applied this strategy using four RAPD markers composed of single copy or repeated sequences linked to avirulence genes of the rice blast fungus Magnaporthe grisea . Cosmids containing these RAPD markers were easily and rapidly identified allowing the construction of physical contigs at these loci.

  9. Identification of expressed genes during compatible interaction between stripe rust (Puccinia striiformis and wheat using a cDNA library

    Directory of Open Access Journals (Sweden)

    Huang Lili

    2009-12-01

    Full Text Available Abstract Background Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst, is one of the most destructive diseases of wheat worldwide. To establish compatibility with the host, Pst forms special infection structures to invade the plant with minimal damage to host cells. Although compatible interaction between wheat and Pst has been studied using various approaches, research on molecular mechanisms of the interaction is limited. The aim of this study was to develop an EST database of wheat infected by Pst in order to determine transcription profiles of genes involved in compatible wheat-Pst interaction. Results Total RNA, extracted from susceptible infected wheat leaves harvested at 3, 5 and 8 days post inoculation (dpi, was used to create a cDNA library, from which 5,793 ESTs with high quality were obtained and clustered into 583 contigs and 2,160 singletons to give a set of 2,743 unisequences (GenBank accessions: GR302385 to GR305127. The BLASTx program was used to search for homologous genes of the unisequences in the GenBank non-redundant protein database. Of the 2,743 unisequences, 52.8% (the largest category were highly homologous to plant genes; 16.3% to fungal genes and 30% of no-hit. The functional classification of all ESTs was established based on the database entry giving the best E-value using the Bevan's classification categories. About 50% of the ESTs were significantly homologous to genes encoding proteins with known functions; 20% were similar to genes encoding proteins with unknown functions and 30% did not have significant homology to any sequence in the database. The quantitative real-time PCR (qRT-PCR analysis determined the transcription profiles and their involvement in the wheat-Pst interaction for seven of the gene. Conclusion The cDNA library is useful for identifying the functional genes involved in the wheat-Pst compatible interaction, and established a new database for studying Pst pathogenesis genes

  10. Survey of a cDNA library from the turkey (Meleagris gallopavo).

    Science.gov (United States)

    Chaves, L D; Rowe, J A; Reed, K M

    2005-02-01

    Genome characterization and analysis is an imperative step in identifying and selectively breeding for improved traits of agriculturally important species. Expressed sequence tags (ESTs) represent a transcribed portion of the genome and are an effective way to identify genes within a species. Downstream applications of EST projects include DNA microarray construction and interspecies comparisons. In this study, 694 ESTs were sequenced and analyzed from a library derived from a 24-day-old turkey embryo. The 437 unique sequences identified were divided into 76 assembled contigs and 361 singletons. The majority of significant comparative matches occurred between the turkey sequences and sequences reported from the chicken. Whole genome sequence from the chicken was used to identify potential exon-intron boundaries for selected turkey clones and intron-amplifying primers were developed for sequence analysis and single nucleotide polymorphism (SNP) discovery. Identified SNPs were genotyped for linkage analysis on two turkey reference populations. This study significantly increases the number of EST sequences available for the turkey.

  11. A cDNA library of the eutardigrade Hypsibius klebelsbergi Mihelčič, 1959 and analysis of the actin gene

    Directory of Open Access Journals (Sweden)

    Hartmut GREVEN

    2007-09-01

    Full Text Available A cDNA library was constructed from the glacier-dwelling eutardigrade Hypsibius klebelsbergi from more than 2000 individuals collected in the Austrian Central Alps. RNA, DNA and proteins were successively isolated by the Trizol®-method. From the RNA preparation a cDNA library was constructed with the cDNA inserted unidirectionally in the phagemid expression vector TriplEx2. The primary gene library had a titre of 107 pfu ml-1 and the final amplified gene library a titre of 6×109 pfu ml-1. The average insert length was about 1.6 kb. The partial sequence of H. klebelsbergi actin (746 bp showed highest similarity to GenBank data of Drosophila melanogaster actin at the nucleic acid level (84.9% and at the amino acid level (98%. Compared with actin fragments of the eutardigrades Ramazzottius oberhaeuseri (450 bp and Macrobiotus sp. (453 bp the identities were 85% - 81% and 100% - 98% with respect to the nucleic/amino acids. Identity with actin fragments (359 bp of Hypsibius dujardini from GenBank was 96% - 100%.

  12. Construction of the Seed-Coat cDNA Microarray and Screening of Differentially Expressed Genes in Barley

    Institute of Scientific and Technical Information of China (English)

    Jin-Song PANG; Meng-Yuan HE; Bao LIU

    2004-01-01

    Some barley mutants can synthesize neither anthocyanins nor proanthocyanidins in the seed coat, which is related to several genes in locus Ant13, but the exact model of action remains unknown. We used the cDNA microarray technology with barley transcription-deficient mutant (ant13-152) that does not synthesize proanthocyanidins as the tester, and its wild type genotype (Triumph) as the driver, to study this question. Six-thousand and forty-eight clones from the wild type Morex testa+pericarp cDNA library were amplified using PCR, and the DNA fragments were spotted on commercial amino-modified glass slide as microarray. The mRNAs from the developing seed coat (8-15 days) of both the mutant and the wild-type barley plants were isolated, and labeled respectively with Cy3-dUTP and Cy5-dUTP when reversely transcribed to cDNAs. The labeled cDNAs were used as probes, mixed at the same molar concentration, and hybridized with the DNA fragments on the slide. Seventy clones exhibiting marked differential expression (ratio>4) were identified from the microarray. All the 25 cDNA clones that showed an over-expression in wild type in comparison to the mutant ant13-152 were sequenced. It was found that most of these overexpressing clones were transcription/translation and hordein-associated genes. These results have laid a solid material basis for further elucidation of the metabolic pathway in proanthocyanidin synthesis in barley and likely other plants.

  13. Studies of the hyperthermophile Thermotoga maritima by random sequencing of cDNA and genomic libraries. Identification and sequencing of the trpEG (D) operon.

    Science.gov (United States)

    Kim, C W; Markiewicz, P; Lee, J J; Schierle, C F; Miller, J H

    1993-06-20

    Random sequencing of cDNA and genomic libraries has been used to study the genome of the hyperthermophile Thermotoga maritima. To date, 175 unique clones have been analyzed by comparing short sequence tags with known proteins in the PIR and GenBank databases. We find that a significant proportion of sequences can be matched to previously identified protein from non-Thermotoga sources. A high match rate was obtained from an oligo(dT)-primed cDNA library, where one-third of all unique sequences analyzed (21/65) shared high amino acid sequence similarity with proteins in the PIR and GenBank databases. Also, approximately one-third of the unique sequences from a second cDNA library (28/89), constructed with random oligo primers, could be matched to sequences in PIR and GenBank. Identification of genes from the oligo(dT)-primed cDNA library indicates that some Thermotoga mRNAs are polyadenylated. Genes have also been identified from a 1 to 2 kb genomic DNA library. Here, (3/21) of genomic sequences analyzed could be matched to protein in PIR and GenBank. One of the genomic clones had high sequence similarity to the tryptophan synthesis gene anthranilate synthase component I (trpE). Using this sequence tag, the Thermotoga trp operon was isolated and sequenced. The Thermotoga maritima trp operon is arranged with trpE forming an overlapping transcript with a second protein consisting of a fusion of anthranilate synthase component II (trpG) and anthranilate phosphoribosyltransferse (trpD). With regard to the fusion, the operon organization is similar to Escherichia coli and Salmonella typhimurium, but lacks the classic attenuation system of enteric bacteria. Amino acid sequence comparison with 19 trpE, 18 trpG and 14 trpD genes from other organisms suggest that the Thermotoga trp genes resemble corresponding genes from other thermophiles more closely than expected.

  14. Expressed sequence tags analysis of a liver tissue cDNA library from a highly inbred minipig line

    Institute of Scientific and Technical Information of China (English)

    CHEN You-nan; TAN Wei-dong; LU Yan-rong; QIN Sheng-fang; LI Sheng-fu; ZENG Yang-zhi; BU Hong; LI You-ping; CHENG Jing-qiu

    2007-01-01

    Background Porcine liver performing efficient physiological functions in the human body is prerequisite for successful liver xenotransplantation. However, the protein differences between pig and human remain largely unexplored. Therefore,we investigated the liver expression profile of a highly inbred minipig line.Methods A cDNA library was constructed from liver tissue of an inbred Banna minipig. Two hundred randomly selected clones were sequenced then analysed by BLAST programme.Results Alignments of the sequences showed 44% encoded previously known porcine genes. Among the 56% unknown genes, sequences of 72 clones had high similarities with known genes of other species and the similarities to human were mostly above 0.80. The other 40 clones showing no similarity to genes in National Centre for Biotechnology Information are newly discovered, expressed sequence tags specific to liver of inbred Banna minipig. Twenty-two of the 200 clones had full length encoding regions, 38 complete 5' terminal sequences and 140 complete 3' terminal sequences.Conclusion These newly discovered expression sequences may be an important resource for research involving physiological characteristics and medical usage of inbred pigs and contribute to matching studies in xenotransplantation.

  15. Transcriptome generation and analysis from spleen of Indian catfish, Clarias batrachus (Linnaeus, 1758) through normalized cDNA library.

    Science.gov (United States)

    Singh, Akanksha; Barman, A S; Sood, Neeraj; Mohindra, Vindhya

    2013-12-01

    Catfishes are commercially important fish for both the fisheries and aquaculture industry. Clarias batrachus, an Indian catfish species is economically important owing to its high demand. A normalized cDNA library was constructed from spleen of the Indian catfish to identify genes associated with immune function. One thousand nine hundred thirty seven ESTs were submitted to the GenBank with an average read length of approximately 700 bp. Clustering analysis of ESTs yielded 1,698 unique sequences, including 184 contigs and 1,514 singletons. Significant homology to known genes was found by homology searches against data in GenBank in 576 (34 %) ESTs, including similarity to functionally annotated unigenes for 158 ESTs. Additionally, 433 ESTs revealed similarity to unigenes and ESTs in the dbEST but the remaining 658 EST sequences (39 %) did not match any sequence in GenBank. Of a total of 1,698 ESTs generated, 65 ESTs were found to be associated with immune functions. Gene Ontology and KEGG pathway analyses of C. batrachus ESTs collectively revealed a preponderance of immune relevant pathways apart from the presence of pathways involved in protein processing, localization, folding and protein degradation. This study constitutes first EST analysis of lymphoid organ in aquaculturally important Indian catfish species and could pave the way for further research of immune-related genes and functional genomics in this catfish.

  16. Construction of a cDNA library and preliminary analysis of expressed sequence tags in Piper hainanense.

    Science.gov (United States)

    Fan, R; Ling, P; Hao, C Y; Li, F P; Huang, L F; Wu, B D; Wu, H S

    2015-10-19

    Black pepper is a perennial climbing vine. It is widely cultivated because its berries can be utilized not only as a spice in food but also for medicinal use. This study aimed to construct a standardized, high-quality cDNA library to facilitated identification of new Piper hainanense transcripts. For this, 262 unigenes were used to generate raw reads. The average length of these 262 unigenes was 774.8 bp. Of these, 94 genes (35.9%) were newly identified, according to the NCBI protein database. Thus, identification of new genes may broaden the molecular knowledge of P. hainanense on the basis of Clusters of Orthologous Groups and Gene Ontology categories. In addition, certain basic genes linked to physiological processes, which can contribute to disease resistance and thereby to the breeding of black pepper. A total of 26 unigenes were found to be SSR markers. Dinucleotide SSR was the main repeat motif, accounting for 61.54%, followed by trinucleotide SSR (23.07%). Eight primer pairs successfully amplified DNA fragments and detected significant amounts of polymorphism among twenty-one piper germplasm. These results present a novel sequence information of P. hainanense, which can serve as the foundation for further genetic research on this species.

  17. Screening for candidate genes related to breast cancer with cDNA microarray analysis

    Institute of Scientific and Technical Information of China (English)

    Yu-Juan Xiang; Zhi-Gang Yu; Ming-Ming Guo; Qin-Ye Fu; Zhong-Bing Ma; De-Zong Gao; Qiang Zhang; Yu-Yang Li; Liang Li; Lu Liu; Chun-Miao Ye

    2015-01-01

    Objective: The aim of this study was to reveal the exact changes during the occurrence of breast cancer to explore significant new and promising genes or factors related to this disease. Methods: We compared the gene expression profiles of breast cancer tissues with its uninvolved normal breast tissues as controls using the cDNA microarray analysis in seven breast cancer patients. Further, one representative gene, named IFI30, was quanti-tatively analyzed by real-time PCR to confirm the result of the cDNA microarray analysis. Results: A total of 427 genes were identified with significantly differential expression, 221 genes were up-regulated and 206 genes were down-regulated. And the result of cDNA microarray analysis was validated by detection of IFI30 mRNA level changes by real-time PCR. Genes for cell proliferation, cell cycle, cell division, mitosis, apoptosis, and immune response were enriched in the up-regulated genes, while genes for cell adhesion, proteolysis, and transport were significantly enriched in the down-regulated genes in breast cancer tissues compared with normal breast tissues by a gene ontology analysis. Conclusion: Our present study revealed a range of differentially expressed genes between breast cancer tissues and normal breast tissues, and provide candidate genes for further study focusing on the pathogenesis and new biomarkers for breast cancer. Copyright © 2015, Chinese Medical Association Production. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  18. 莫氏巴贝斯虫裂殖子cDNA表达文库的构建及免疫学筛选%Construction and Immunoscreening of a Merozoites cDNA Expression Library of Babesia motasi

    Institute of Scientific and Technical Information of China (English)

    王锦明; 罗建勋; 殷宏; 关贵全; 刘军龙; 刘爱红; 马米玲; 牛庆丽; 任巧云; 杨吉飞; 刘志杰; 李有全

    2012-01-01

    为了构建莫氏巴贝斯虫(Babesia motasi)裂殖子cDNA表达文库,从中筛选和鉴定功能基因,利用差速离心法从莫氏巴贝斯虫感染的红细胞中纯化裂殖子,提取总RNA并纯化mRNA.在合成的双链cDNA两端加上含EcoRⅠ和Hind Ⅲ定向接头后连接到λ SCREEN载体上.通过体外包装形成完整的噬菌体颗粒,并用之转染ER1647,构建莫氏巴贝斯虫裂殖子的cDNA表达文库.用莫氏巴贝斯虫阳性血清筛选cDNA文库,获得的阳性克隆,经过测序和Blast软件分析鉴定,然后利用末端快速扩增技术(RACE)对筛选到的功能基因片段进行全长扩增.结果表明构建的cDNA表达文库其初级库容量约为1.0×106 PFU,扩增文库为3.5×109 PFU;通过免疫学筛选,获得50个阳性克隆.测序和Blast分析后,鉴定出10个莫氏巴贝斯虫基因片段,RACE扩增获得了其中8个基因的全长.本试验构建的莫氏巴贝斯虫裂殖子的cDNA表达文库和筛选到的10个结构和功能基因,为研究巴贝斯虫生物学特性、筛选疫苗与诊断用抗原及药物靶位奠定了基础.%The objective of this study was to obtain functional genes of Babesia motasi, a cDNA expression library of the merozoites was constructed and immunoscreened with positive sera from sheep infected with B. motasi. The merozoites of B. motasi were purified from red blood cell with differential centrifugation. The mRNA was purified from extracted total RNA. Synthetized double-strand cDNA was added directional EcoR I /Hind H linkers and ligated to the EcoR I / Hind III arms of X screen vector. To produce a primary cDNA library of B. motasi, the phages DNA was packaged in vitro and transfected into ER1647. The positive clones were obtained by immunoscreening with the positive sera against B. motasi and amplified with rapid amplificationof cDNA ends (RACE). The titers of the primary and amplified cDNA expression library were 1. 0X106 PFU and 3. 5X1O9PFU ·mL-1, respectively. The results

  19. Using genome-wide CRISPR library screening with library resistant DCK to find new sources of Ara-C drug resistance in AML.

    Science.gov (United States)

    Kurata, Morito; Rathe, Susan K; Bailey, Natashay J; Aumann, Natalie K; Jones, Justine M; Veldhuijzen, G Willemijn; Moriarity, Branden S; Largaespada, David A

    2016-11-03

    Acute myeloid leukemia (AML) can display de novo or acquired resistance to cytosine arabinoside (Ara-C), a primary component of induction chemotherapy. To identify genes capable of independently imposing Ara-C resistance, we applied a genome-wide CRISPR library to human U937 cells and exposed to them to Ara-C. Interestingly, all drug resistant clones contained guide RNAs for DCK. To avoid DCK gene modification, gRNA resistant DCK cDNA was created by the introduction of silent mutations. The CRISPR screening was repeated using the gRNA resistant DCK, and loss of SLC29A was identified as also being capable of conveying Ara-C drug resistance. To determine if loss of Dck results in increased sensitivity to other drugs, we conducted a screen of 446 FDA approved drugs using two Dck-defective BXH-2 derived murine AML cell lines and their Ara-C sensitive parental lines. Both cell lines showed an increase in sensitivity to prednisolone. Guide RNA resistant cDNA rescue was a legitimate strategy and multiple DCK or SLC29A deficient human cell clones were established with one clone becoming prednisolone sensitive. Dck-defective leukemic cells may become prednisolone sensitive indicating prednisolone may be an effective adjuvant therapy in some cases of DCK-negative AML.

  20. Using genome-wide CRISPR library screening with library resistant DCK to find new sources of Ara-C drug resistance in AML

    Science.gov (United States)

    Kurata, Morito; Rathe, Susan K.; Bailey, Natashay J.; Aumann, Natalie K.; Jones, Justine M.; Veldhuijzen, G. Willemijn; Moriarity, Branden S.; Largaespada, David A.

    2016-01-01

    Acute myeloid leukemia (AML) can display de novo or acquired resistance to cytosine arabinoside (Ara-C), a primary component of induction chemotherapy. To identify genes capable of independently imposing Ara-C resistance, we applied a genome-wide CRISPR library to human U937 cells and exposed to them to Ara-C. Interestingly, all drug resistant clones contained guide RNAs for DCK. To avoid DCK gene modification, gRNA resistant DCK cDNA was created by the introduction of silent mutations. The CRISPR screening was repeated using the gRNA resistant DCK, and loss of SLC29A was identified as also being capable of conveying Ara-C drug resistance. To determine if loss of Dck results in increased sensitivity to other drugs, we conducted a screen of 446 FDA approved drugs using two Dck-defective BXH-2 derived murine AML cell lines and their Ara-C sensitive parental lines. Both cell lines showed an increase in sensitivity to prednisolone. Guide RNA resistant cDNA rescue was a legitimate strategy and multiple DCK or SLC29A deficient human cell clones were established with one clone becoming prednisolone sensitive. Dck-defective leukemic cells may become prednisolone sensitive indicating prednisolone may be an effective adjuvant therapy in some cases of DCK-negative AML. PMID:27808171

  1. Construction and identification of directional cDNA library from Chinese giant salamander Andrias davidianus liver%大鲵肝脏组织定向cDNA文库的构建及鉴定

    Institute of Scientific and Technical Information of China (English)

    杨芳; 贺智敏; 詹显全; 陈主初; 严斌; 黄宏科; 李廷宝

    2004-01-01

    To construct a directional cDNA library from Chinese giant salamander Andrias davidianus liver by SMART (switching mechanism at 5' end of RNA transcript) technique, we purified the mRNA from Andrias davidianus liver and the first-strand cDNA was synthesized through reverse transcription by using a modified oligo (dT) primer (contained sfi Ⅰ B site). We used the SMART oligonucleotide (contained sfi Ⅰ A site) as a template so that the first-strand cDNA could be extended over the 5' end of mRNA. The double-strand cDNA was amplified by LD-PCR (long-distancePCR) with the above two primers and then digested by sfi Ⅰ ( Ⅰ A and Ⅰ B) restriction enzyme. After cDNA fractionation through CHROMA SPIN column, the double-strand cDNA was ligated into the sfi Ⅰ -digested λtripIEx2 vector and then the recombinant DNA was packaged in vitro. The content of the unamplified Andrias davidianus liver cDNA library is 1.5 × 106 in which the percentage of recombinant clones is about 98.9 %. The titer of the amplified cDNA library is 1.0 × 1010 pfu/ml and the average exogenous inserts of the recombinants is 1.25 kb. These results show that the Andrias davidianus liver cDNA library has excellent quality [Acta Zoologica Sinica 50 (3): 475 -478, 2004].

  2. Construction of a full-length enriched cDNA library and preliminary analysis of expressed sequence tags from Bengal Tiger Panthera tigris tigris.

    Science.gov (United States)

    Liu, Changqing; Liu, Dan; Guo, Yu; Lu, Taofeng; Li, Xiangchen; Zhang, Minghai; Ma, Jianzhang; Ma, Yuehui; Guan, Weijun

    2013-05-24

    In this study, a full-length enriched cDNA library was successfully constructed from Bengal tiger, Panthera tigris tigris, the most well-known wild Animal. Total RNA was extracted from cultured Bengal tiger fibroblasts in vitro. The titers of primary and amplified libraries were 1.28 × 106 pfu/mL and 1.56 × 109 pfu/mL respectively. The percentage of recombinants from unamplified library was 90.2% and average length of exogenous inserts was 0.98 kb. A total of 212 individual ESTs with sizes ranging from 356 to 1108 bps were then analyzed. The BLASTX score revealed that 48.1% of the sequences were classified as a strong match, 45.3% as nominal and 6.6% as a weak match. Among the ESTs with known putative function, 26.4% ESTs were found to be related to all kinds of metabolisms, 19.3% ESTs to information storage and processing, 11.3% ESTs to posttranslational modification, protein turnover, chaperones, 11.3% ESTs to transport, 9.9% ESTs to signal transducer/cell communication, 9.0% ESTs to structure protein, 3.8% ESTs to cell cycle, and only 6.6% ESTs classified as novel genes. By EST sequencing, a full-length gene coding ferritin was identified and characterized. The recombinant plasmid pET32a-TAT-Ferritin was constructed, coded for the TAT-Ferritin fusion protein with two 6× His-tags in N and C-terminal. After BCA assay, the concentration of soluble Trx-TAT-Ferritin recombinant protein was 2.32 ± 0.12 mg/mL. These results demonstrated that the reliability and representativeness of the cDNA library attained to the requirements of a standard cDNA library. This library provided a useful platform for the functional genome and transcriptome research of Bengal tigers.

  3. Analysis of Current DNA Encoded Library Screening Data Indicates Higher False Negative Rates for Numerically Larger Libraries.

    Science.gov (United States)

    Satz, Alexander L; Hochstrasser, Remo; Petersen, Ann C

    2017-04-10

    To optimize future DNA-encoded library design, we have attempted to quantify the library size at which the signal becomes undetectable. To accomplish this we (i) have calculated that percent yields of individual library members following a screen range from 0.002 to 1%, (ii) extrapolated that ∼1 million copies per library member are required at the outset of a screen, and (iii) from this extrapolation predict that false negative rates will begin to outweigh the benefit of increased diversity at library sizes >10(8). The above analysis is based upon a large internal data set comprising multiple screens, targets, and libraries; we also augmented our internal data with all currently available literature data. In theory, high false negative rates may be overcome by employing larger amounts of library; however, we argue that using more than currently reported amounts of library (≫10 nmoles) is impractical. The above conclusions may be generally applicable to other DNA encoded library platforms, particularly those platforms that do not allow for library amplification.

  4. The characterisation of tapetum-specific cDNAs isolated from a Lilium henryi L. meiocyte subtractive cDNA library.

    Science.gov (United States)

    Crossley, S J; Greenland, A J; Dickinson, H G

    1995-01-01

    Differential screening of a meiocyte subtractive cDNA library from Lilium henryi L. has identified a group of 16 anther-specific partial cDNAs. Three of these sequences, LHM2, LHM6 and LHM7 have been further characterised. Hybridisation in situ with antisense riboprobes of LHM2, LHM6, and LHM7 gives a strong, clear signal which, contrary to expectations, is localised to the tapetal layer surrounding the meiocytes and not the meiocytes themselves. Developmental slot blots demonstrate that mRNAs corresponding to the three LHM cDNAs are transcribed from prophase of meiosis I to the uninucleate microspore stage, while Northern analysis reveals these tapetally expressed cDNAs to correspond with transcripts of some 500 bp. Although LHM2 is less abundant than LHM6 and LHM7, the pattern of developmental expression, and the size range of the transcripts suggests that all three cDNAs may be related. The deduced polypeptide products of LHM6 and LHM7 share 71% identity over a conserved region of 38 residues. Inverse polymerase chain reaction was used to obtain the full sequence for LHM7. Its deduced protein sequence has a signal peptide indicating it may be secreted; the cleaved protein has a molecular weight of 8.9 kDa. Furthermore, the LHM7 protein has significant levels of homology with tapetally expressed proteins from Arabidopsis thaliana, Antirrhinum majus and Lycopersicon esculentum. All contain a highly conserved pattern of cysteine residues present in seed and non-specific lipid transfer proteins. The function of this gene product is discussed in the perspective of current models of another development.

  5. Large-scale Identification of Expressed Sequence Tags (ESTs from Nicotianatabacum by Normalized cDNA Library Sequencing

    Directory of Open Access Journals (Sweden)

    Alvarez S Perez

    2014-12-01

    Full Text Available An expressed sequence tags (EST resource for tobacco plants (Nicotianatabacum was established using high-throughput sequencing of randomly selected clones from one cDNA library representing a range of plant organs (leaf, stem, root and root base. Over 5000 ESTs were generated from the 3’ ends of 8000 clones, analyzed by BLAST searches and categorized functionally. All annotated ESTs were classified into 18 functional categories, unique transcripts involved in energy were the largest group accounting for 831 (32.32% of the annotated ESTs. After excluding 2450 non-significant tentative unique transcripts (TUTs, 100 unique sequences (1.67% of total TUTs were identified from the N. tabacum database. In the array result two genes strongly related to the tobacco mosaic virus (TMV were obtained, one basic form of pathogenesis-related protein 1 precursor (TBT012G08 and ubiquitin (TBT087G01. Both of them were found in the variety Hongda, some other important genes were classified into two groups, one of these implicated in plant development like those genes related to a photosynthetic process (chlorophyll a-b binding protein, photosystem I, ferredoxin I and III, ATP synthase and a further group including genes related to plant stress response (ubiquitin, ubiquitin-like protein SMT3, glycine-rich RNA binding protein, histones and methallothionein. The interesting finding in this study is that two of these genes have never been reported before in N. tabacum (ubiquitin-like protein SMT3 and methallothionein. The array results were confirmed using quantitative PCR.

  6. Library screening and receptor-directed targeting of gammaretroviral vectors.

    Science.gov (United States)

    Mazari, Peter M; Roth, Monica J

    2013-01-01

    Gene- and cell-based therapies hold great potential for the advancement of the personalized medicine movement. Gene therapy vectors have made dramatic leaps forward since their inception. Retroviral-based vectors were the first to gain clinical attention and still offer the best hope for the long-term correction of many disorders. The fear of nonspecific transduction makes targeting a necessary feature for most clinical applications. However, this remains a difficult feature to optimize, with specificity often coming at the expense of efficiency. The aim of this article is to discuss the various methods employed to retarget retroviral entry. Our focus will lie on the modification of gammaretroviral envelope proteins with an in-depth discussion of the creation and screening of envelope libraries.

  7. Discovery of the improved antagonistic prolactin variants by library screening.

    Science.gov (United States)

    Liu, Yun; Gong, Wei; Breinholt, Jens; Nørskov-Lauritsen, Leif; Zhang, Jinchao; Ma, Qinhong; Chen, Jianhe; Panina, Svetlana; Guo, Wei; Li, Tengkun; Zhang, Jingyuan; Kong, Meng; Liu, Zibing; Mao, Jingjing; Christensen, Leif; Hu, Sean; Wang, Lingyun

    2011-11-01

    Prolactin (PRL), a potent growth stimulator of the mammary epithelium, has been suggested to be a factor contributing to the development and progression of breast and prostate cancer. Several PRL receptor (PRLR) antagonists have been identified in the past decades, but their in vivo growth inhibitory potency was restricted by low receptor affinity, rendering them pharmacologically unattractive for clinical treatment. Thus, higher receptor affinity is essential for the development of improved PRLR antagonistic variants with improved in vivo potency. In this study, we generated Site 1 focused protein libraries of human G129R-PRL mutants and screened for those with increased affinity to the human PRLR. By combining the mutations with enhanced affinities for PRLR, we identified a novel G129R-PRL variant with mutations at Site 1 that render nearly 50-fold increase in the antagonistic potency in vitro.

  8. [Construction and analysis of a forward and reverse subtractive cDNA library from leaves and stem of Polygonum sibiricum Laxm. under salt stress].

    Science.gov (United States)

    Liu, Guan-Jun; Liu, Ming-Kun; Xu, Zhi-Ru; Yan, Xiu-Feng; Wei, Zhi-Gang; Yang, Chuan-Ping

    2009-04-01

    Using cDNAs prepared from the leaves and stems of Polygonum sibiricum Laxm. treated with NaHCO3 stress for 48 h as testers and cDNAs from unstressed P. sibiricum leaves and stems as drivers library, suppression subtractive hybridization (SSH) was employed to construct a cDNA subtracted library, which contained 2 282 valid sequences including 598 ESTs in the stems forward SSH library and 490 ESTs in the stem reverse SSH library, 627 ESTs in the leaf forward SSH library and 567 in the leaf reverse SSH library. According to the functional catalogue of MIPs and the comparison of the reverse and forward SSH libraries of the stem and leaf, the responses to NaHCO3 stress were different between leaf and stem, except for the same trend in cell rescue defense and transport facilitation. The trend in the metabolism, energy, photosynthesis, protein synthesis, transcription, and signal transduction was opposite. RT-PCR analysis demonstrated that the expression of 12 putative stress related genes in the NaHCO3-treated leaves and stems was different from that in the untreated leaves and stems. This indicated that different mechanisms might be responsible for reactions of leaf and stem in P. sibiricum. The results from this study are useful in understanding the molecular mechanism of saline-alkali tolerance in P. sibiricum.

  9. Superfamily-wide portrait of serine hydrolase inhibition achieved by library-versus-library screening.

    Science.gov (United States)

    Bachovchin, Daniel A; Ji, Tianyang; Li, Weiwei; Simon, Gabriel M; Blankman, Jacqueline L; Adibekian, Alexander; Hoover, Heather; Niessen, Sherry; Cravatt, Benjamin F

    2010-12-07

    Serine hydrolases (SHs) are one of the largest and most diverse enzyme classes in mammals. They play fundamental roles in virtually all physiological processes and are targeted by drugs to treat diseases such as diabetes, obesity, and neurodegenerative disorders. Despite this, we lack biological understanding for most of the 110+ predicted mammalian metabolic SHs, in large part because of a dearth of assays to assess their biochemical activities and a lack of selective inhibitors to probe their function in living systems. We show here that the vast majority (> 80%) of mammalian metabolic SHs can be labeled in proteomes by a single, active site-directed fluorophosphonate probe. We exploit this universal activity-based assay in a library-versus-library format to screen 70+ SHs against 140+ structurally diverse carbamates. Lead inhibitors were discovered for ∼40% of the screened enzymes, including many poorly characterized SHs. Global profiles identified carbamate inhibitors that discriminate among highly sequence-related SHs and, conversely, enzymes that share inhibitor sensitivity profiles despite lacking sequence homology. These findings indicate that sequence relatedness is not a strong predictor of shared pharmacology within the SH superfamily. Finally, we show that lead carbamate inhibitors can be optimized into pharmacological probes that inactivate individual SHs with high specificity in vivo.

  10. A primer on using pooled shRNA libraries for functional genomic screens

    Institute of Scientific and Technical Information of China (English)

    Guang Hu; Ji Luo

    2012-01-01

    The discovery of RNA interference (RNAi) has revolutionized genetic analysis in mammalian cells.Loss-of-function RNAi screens enable rapid,functional annotation of the genome.Of the various RNAi approaches,pooled shRNA libraries have received considerable attention because of their versatility.A number of genome-wide shRNA libraries have been constructed against the human and mouse genomes,and these libraries can be readily applied to a variety of screens to interrogate the function of human and mouse genes in an unbiased fashion.We provide an introduction to the technical aspects of using pooled shRNA libraries for genetic screens.

  11. Extending Immunological Profiling in the Gilthead Sea Bream, Sparus aurata, by Enriched cDNA Library Analysis, Microarray Design and Initial Studies upon the Inflammatory Response to PAMPs

    Directory of Open Access Journals (Sweden)

    Sebastian Boltaña

    2017-02-01

    Full Text Available This study describes the development and validation of an enriched oligonucleotide-microarray platform for Sparus aurata (SAQ to provide a platform for transcriptomic studies in this species. A transcriptome database was constructed by assembly of gilthead sea bream sequences derived from public repositories of mRNA together with reads from a large collection of expressed sequence tags (EST from two extensive targeted cDNA libraries characterizing mRNA transcripts regulated by both bacterial and viral challenge. The developed microarray was further validated by analysing monocyte/macrophage activation profiles after challenge with two Gram-negative bacterial pathogen-associated molecular patterns (PAMPs; lipopolysaccharide (LPS and peptidoglycan (PGN. Of the approximately 10,000 EST sequenced, we obtained a total of 6837 EST longer than 100 nt, with 3778 and 3059 EST obtained from the bacterial-primed and from the viral-primed cDNA libraries, respectively. Functional classification of contigs from the bacterial- and viral-primed cDNA libraries by Gene Ontology (GO showed that the top five represented categories were equally represented in the two libraries: metabolism (approximately 24% of the total number of contigs, carrier proteins/membrane transport (approximately 15%, effectors/modulators and cell communication (approximately 11%, nucleoside, nucleotide and nucleic acid metabolism (approximately 7.5% and intracellular transducers/signal transduction (approximately 5%. Transcriptome analyses using this enriched oligonucleotide platform identified differential shifts in the response to PGN and LPS in macrophage-like cells, highlighting responsive gene-cassettes tightly related to PAMP host recognition. As observed in other fish species, PGN is a powerful activator of the inflammatory response in S. aurata macrophage-like cells. We have developed and validated an oligonucleotide microarray (SAQ that provides a platform enriched for the study

  12. Extending Immunological Profiling in the Gilthead Sea Bream, Sparus aurata, by Enriched cDNA Library Analysis, Microarray Design and Initial Studies upon the Inflammatory Response to PAMPs

    Science.gov (United States)

    Boltaña, Sebastian; Castellana, Barbara; Goetz, Giles; Tort, Lluis; Teles, Mariana; Mulero, Victor; Novoa, Beatriz; Figueras, Antonio; Goetz, Frederick W.; Gallardo-Escarate, Cristian; Planas, Josep V.; Mackenzie, Simon

    2017-01-01

    This study describes the development and validation of an enriched oligonucleotide-microarray platform for Sparus aurata (SAQ) to provide a platform for transcriptomic studies in this species. A transcriptome database was constructed by assembly of gilthead sea bream sequences derived from public repositories of mRNA together with reads from a large collection of expressed sequence tags (EST) from two extensive targeted cDNA libraries characterizing mRNA transcripts regulated by both bacterial and viral challenge. The developed microarray was further validated by analysing monocyte/macrophage activation profiles after challenge with two Gram-negative bacterial pathogen-associated molecular patterns (PAMPs; lipopolysaccharide (LPS) and peptidoglycan (PGN)). Of the approximately 10,000 EST sequenced, we obtained a total of 6837 EST longer than 100 nt, with 3778 and 3059 EST obtained from the bacterial-primed and from the viral-primed cDNA libraries, respectively. Functional classification of contigs from the bacterial- and viral-primed cDNA libraries by Gene Ontology (GO) showed that the top five represented categories were equally represented in the two libraries: metabolism (approximately 24% of the total number of contigs), carrier proteins/membrane transport (approximately 15%), effectors/modulators and cell communication (approximately 11%), nucleoside, nucleotide and nucleic acid metabolism (approximately 7.5%) and intracellular transducers/signal transduction (approximately 5%). Transcriptome analyses using this enriched oligonucleotide platform identified differential shifts in the response to PGN and LPS in macrophage-like cells, highlighting responsive gene-cassettes tightly related to PAMP host recognition. As observed in other fish species, PGN is a powerful activator of the inflammatory response in S. aurata macrophage-like cells. We have developed and validated an oligonucleotide microarray (SAQ) that provides a platform enriched for the study of gene

  13. Construction and Identification ofa cDNA Library of Human Rheumatoid Arthritis Synovial Tissue%人类风湿性关节炎滑膜组织cDNA文库的构建

    Institute of Scientific and Technical Information of China (English)

    闫永毅; 任蕾; 高飞; 卢秀敏; 刘彦虹

    2012-01-01

    Objective:To construct a cDNA library of human synovial tissue of RA and indentify the quality of the library. Methods: Total RNA was extracted and mRNA was purified. mRNA was reversed to first-strand cDNA which was amplified to double-strand cD-NA by long distance PCR. PCR products were digested by proteinase K and Sfi I, and were fractionated by CHROMA SPIN-400 column. The cDN A of length longer than 0.4kb were collected and ligated toλ TriplEx2 vector. The λ phage packaging reaction for the ligated DNA was performed to produce an unamplified library. Thereafter, the unamplified library was titered and the percentage of recombinant clones were detected. In the end, fourty plaques were randomly selected and amplified by PCR using universal primers from vector in order to test the qualify of the obtained library. Results: The titers of unamplifed and amplified libraries were 6.89x106 pfu/mL and 2.63x 109 pfu/mL respectively. The rate of recombinant was 93%. The insert size range from 300 to 1800 bp. Conclusions: A high quality cD-NA library from human synovial tissue of RA was constructed successfully, and it lays solid foundation not only for screening and cloning new special genes associated with the occurrence of RA, but also for gene therapy of it.%目的:构建人类风湿关节炎(RA)滑膜组织cDNA文库.筛查与RA相关的特异基因,为探讨RA的发病机制及基因治疗奠定基础.方法:提取人类风湿关节炎滑膜组织RNA并使用Trizol法纯化mRNA;运用mRNA5'末端的模板转换方法以powerscriptTM逆转录酶进行转录,使用COS Ⅲ/3'PCR引物合成第1链cDNAs;长距离聚合酶链反应(LD-PCR)合成双链cDNA; PCR产物经蛋白酶K水解并纯化后,经SfiI酶切、柱层析洗脱,重组于TripIEx2载体并包装后,测定滴度、重组率、扩增文库,随机挑取40个噬菌斑,用载体克隆位点两端的通用引物进行PCR扩增,以检测所构建cDNA文库的质量.结果:未扩增文库的滴度为6.89× 106pfu/m

  14. [Three-dimensional PCR-based screening of Chinese fine wool merino sheep BAC library].

    Science.gov (United States)

    Wu, Xindong; Chen, Fang; Li, Xin; Zou, Yihui; Qiu, Wei; Gao, Jianfeng

    2008-10-01

    For rapid screening, we constructed two levels pools (primary and secondary pools) of the bacterial artificial chromosome (BAC) library of Chinese fine wool merino sheep. The primary pools were based on the individual 384-well microtiter plate and were prepared with a three-dimensional pooling scheme. Three dimension (plate, row and column) pools were made for each. The secondary pools were based on the entire BAC library. We developed a PCR based strategy to identify positive BACs from sheep BAC library. First, we analyzed secondary pools DNAs, according to the result, we analyzed correlative primary pools. It was one-step screening (66 PCR reactions) that we could screen a single positive clone from 74 000 BACs by our method, or three-step screening (less than 100 PCR reactions) could screen more clones. By one-step screening (66 PCR reactions), we screened successfully a positive clone 373D13 with polymorphism marker BF94-1.

  15. Combinatorial problems arising from pooling designs for dna library screening

    Directory of Open Access Journals (Sweden)

    Masakazu Jimbo

    2004-11-01

    Full Text Available Colbourn (1999 developed some strategy for nonadaptive group testing when the items are linearly ordered and the positive items form a consecutive subset of all items.Müller and Jimbo (2004 improved his strategy by introducing the concept of 2-consecutive positive detectable matrices (2CPD-matrix requiring that all columns and bitwise OR-sum of each two consecutive columns are pairwise distinct. Such a matrix is called maximal if it has a maximal possible number of columns with respect to some obvious constraints. Using a recursive construction they proved the existence of maximal 2CPD-matrices for any column size m ∈ N except for the case m = 3. Moreover, maximal 2CPD-matrices such that each column is of some fixed constant weight areconstructed. This leads to pooling designs, where each item appears in the same number of pools and all pools are of the same size.Secondly, we investigate 2CPD-matrices of some constant column weight τ ∈ N. We give some recursive construction of such matrices having the maximal possible number of columns. Thirdly, error correction capability of group testing procedures is essential in view of applications such as DNA library screening. We consider a error correcting 2CPD-matrices.

  16. Modifying culture conditions in chemical library screening identifies alternative inhibitors of mycobacteria.

    Science.gov (United States)

    Miller, Christopher H; Nisa, Shahista; Dempsey, Sandi; Jack, Cameron; O'Toole, Ronan

    2009-12-01

    In this study, application of a dual absorbance/fluorescence assay to a chemical library screen identified several previously unknown inhibitors of mycobacteria. In addition, growth conditions had a significant effect on the activity profile of the library. Some inhibitors such as Se-methylselenocysteine were detected only when screening was performed under nutrient-limited culture conditions as opposed to nutrient-rich culture conditions. We propose that multiple culture condition library screening is required for complete inhibitory profiling and for maximal antimycobacterial compound detection.

  17. A subtractive cDNA library from an identified regenerating neuron is enriched in sequences up-regulated during nerve regeneration.

    Science.gov (United States)

    Korneev, S; Fedorov, A; Collins, R; Blackshaw, S E; Davies, J A

    1997-01-01

    We have constructed a subtractive cDNA library from regenerating Retzius cells of the leech, Hirudo medicinalis. It is highly enriched in sequences up-regulated during nerve regeneration. Sequence analysis of selected recombinants has identified both novel sequences and sequences homologous to molecules characterised in other species. Homologies include alpha-tubulin, a calmodulin-like protein, CAAT/enhancer-binding protein (C/EBP), protein 4.1 and synapsin. These types of proteins are exactly those predicted to be associated with axonal growth and their identification confirms the quality of the library. Most interesting, however, is the isolation of 5 previously uncharacterised cDNAs which appear to be up-regulated during regeneration. Their analysis is likely to provide new information on the molecular mechanisms of neuronal regeneration.

  18. A new set of ESTs and cDNA clones from full-length and normalized libraries for gene discovery and functional characterization in citrus

    Directory of Open Access Journals (Sweden)

    Alamar Santiago

    2009-09-01

    Full Text Available Abstract Background Interpretation of ever-increasing raw sequence information generated by modern genome sequencing technologies faces multiple challenges, such as gene function analysis and genome annotation. Indeed, nearly 40% of genes in plants encode proteins of unknown function. Functional characterization of these genes is one of the main challenges in modern biology. In this regard, the availability of full-length cDNA clones may fill in the gap created between sequence information and biological knowledge. Full-length cDNA clones facilitate functional analysis of the corresponding genes enabling manipulation of their expression in heterologous systems and the generation of a variety of tagged versions of the native protein. In addition, the development of full-length cDNA sequences has the power to improve the quality of genome annotation. Results We developed an integrated method to generate a new normalized EST collection enriched in full-length and rare transcripts of different citrus species from multiple tissues and developmental stages. We constructed a total of 15 cDNA libraries, from which we isolated 10,898 high-quality ESTs representing 6142 different genes. Percentages of redundancy and proportion of full-length clones range from 8 to 33, and 67 to 85, respectively, indicating good efficiency of the approach employed. The new EST collection adds 2113 new citrus ESTs, representing 1831 unigenes, to the collection of citrus genes available in the public databases. To facilitate functional analysis, cDNAs were introduced in a Gateway-based cloning vector for high-throughput functional analysis of genes in planta. Herein, we describe the technical methods used in the library construction, sequence analysis of clones and the overexpression of CitrSEP, a citrus homolog to the Arabidopsis SEP3 gene, in Arabidopsis as an example of a practical application of the engineered Gateway vector for functional analysis. Conclusion The new

  19. Peroxidases identified in a subtractive cDNA library approach show tissue-specific transcript abundance and enzyme activity during seed germination of Lepidium sativum.

    Science.gov (United States)

    Linkies, Ada; Schuster-Sherpa, Uta; Tintelnot, Stefanie; Leubner-Metzger, Gerhard; Müller, Kerstin

    2010-01-01

    The micropylar endosperm is a major regulator of seed germination in endospermic species, to which the close Brassicaceae relatives Arabidopsis thaliana and Lepidium sativum (cress) belong. Cress seeds are about 20 times larger than the seeds of Arabidopsis. This advantage was used to construct a tissue-specific subtractive cDNA library of transcripts that are up-regulated late in the germination process specifically in the micropylar endosperm of cress seeds. The library showed that a number of transcripts known to be up-regulated late during germination are up-regulated in the micropylar endosperm cap. Detailed germination kinetics of SALK lines carrying insertions in genes present in our library showed that the identified transcripts do indeed play roles during germination. Three peroxidases were present in the library. These peroxidases were identified as orthologues of Arabidopsis AtAPX01, AtPrx16, and AtPrxIIE. The corresponding SALK lines displayed significant germination phenotypes. Their transcripts were quantified in specific cress seed tissues during germination in the presence and absence of ABA and they were found to be regulated in a tissue-specific manner. Peroxidase activity, and particularly its regulation by ABA, also differed between radicles and micropylar endosperm caps. Possible implications of this tissue-specificity are discussed.

  20. 红笛鲷头肾消减cDNA文库的构建与分析%Construction and analysis of subtractive cDNA library of head kidney in humphead snapper,Lutjanus sanguineus

    Institute of Scientific and Technical Information of China (English)

    张新中; 吴灶和; 简纪常; 鲁义善

    2011-01-01

    应用抑制性消减杂交技术(SSH)构建红笛鲷(Lutjanus sanguineus)头肾消减cDNA文库,筛选红笛鲷免疫相关基因的EST.以哈氏弧菌(Vibrio harveyi)灭活疫苗体内诱导红笛鲷为实验组,以注射无菌生理盐水的红笛鲷为驱动组,通过SSH技术构建红笛鲷头肾消减.DNA文库.利用PCR技术和斑点杂交对文库进行筛选,从2 424个含插人片段的阳性克隆中筛选了680个克隆在上海生工进行了序列测定.使用BLASTx和BLASTn工具对获得的ESTs与GenBank数据库进行同源性比较并根据相似性序列的名称通过GO法对ESTs进行注释.结果获得了30个与红笛鲷免免疫防御相关基因的EST,如组织相容性抗原复合物基因(MHC I和MHCII),免疫球蛋白基因(IgH和IgL)、热休克蛋白基因(HSP10,HSP70和HSP90)等.本研究构建了哈氏弧菌灭活疫苗免疫后与正常组织差异表达的消减cDNA文库,并获得一批与红笛鲷免疫防御相关的ESTs,旨在为探讨红笛鲷分子免疫防御机制、筛选参与免疫防御调控相关的功能基因,揭示红笛鲷免疫抗病机制、提高机体抗病力、实现遗传改良奠定基础.%A subtracted cDNA library of humphead snapper (Lutjanus sanguineus) was constructed by suppression subtractive hybridization technology (SSH) to screen immune-related EST. The cDNA library has been constructed by the mRNA of the test group and driven by SSH. Differential ESTs from the subtracted cDNA library have been identified by both PCR technology and dot blot hybridization. Six hundred and eighty positive clones were sequenced by Sangon Biological Engineering Technology & Services Co., Ltd. The homology of the sequences was analyzed by BLASTx tool and BLASTn tool in GenBank database. Functional distribution was performed based on the features of ESTs by gene ontology annotation (GO) and 30 immune-related ESTs of L. sanguineus, such as major histocompatibility complex gene (MHC Ⅰ and MHC Ⅱ ), immunoglobulin gene

  1. piggyBac mediates efficient in vivo CRISPR library screening for tumorigenesis in mice.

    Science.gov (United States)

    Xu, Chunlong; Qi, Xiaolan; Du, Xuguang; Zou, Huiying; Gao, Fei; Feng, Tao; Lu, Hengxing; Li, Shenglan; An, Xiaomeng; Zhang, Lijun; Wu, Yuanyuan; Liu, Ying; Li, Ning; Capecchi, Mario R; Wu, Sen

    2017-01-24

    CRISPR/Cas9 is becoming an increasingly important tool to functionally annotate genomes. However, because genome-wide CRISPR libraries are mostly constructed in lentiviral vectors, in vivo applications are severely limited as a result of difficulties in delivery. Here, we examined the piggyBac (PB) transposon as an alternative vehicle to deliver a guide RNA (gRNA) library for in vivo screening. Although tumor induction has previously been achieved in mice by targeting cancer genes with the CRISPR/Cas9 system, in vivo genome-scale screening has not been reported. With our PB-CRISPR libraries, we conducted an in vivo genome-wide screen in mice and identified genes mediating liver tumorigenesis, including known and unknown tumor suppressor genes (TSGs). Our results demonstrate that PB can be a simple and nonviral choice for efficient in vivo delivery of CRISPR libraries.

  2. Combinatorial Library Screening Coupled to Mass Spectrometry to Identify Valuable Cyclic Peptides.

    Science.gov (United States)

    Camperi, Silvia A; Giudicessi, Silvana L; Martínez-Ceron, María C; Gurevich-Messina, Juan M; Saavedra, Soledad L; Acosta, Gerardo; Cascone, Osvaldo; Erra-Balsells, Rosa; Albericio, Fernando

    2016-06-02

    Combinatorial library screening coupled to mass spectrometry (MS) analysis is a practical approach to identify useful peptides. Cyclic peptides can have high biological activity, selectivity, and affinity for target proteins, and high stability against proteolytic degradation. Here we describe two strategies to prepare combinatorial libraries suitable for MS analysis to accelerate the discovery of cyclic peptide structures. Both approaches use ChemMatrix resin and the linker 4-hydroxymethylbenzoic acid. One strategy involves the synthesis of a one-bead-two-peptides library in which each bead contains both the cyclic peptide and its linear counterpart to facilitate MS analysis. The other protocol is based on the synthesis of a cyclic depsipeptide library in which a glycolamidic ester group is incorporated by adding glycolic acid. After library screening, the ring is opened and the peptide is released simultaneously for subsequent MS analysis. © 2016 by John Wiley & Sons, Inc.

  3. Construction and characterization of normalized cDNA libraries by 454 pyrosequencing and estimation of DNA methylation levels in three distantly related termite species.

    Science.gov (United States)

    Hayashi, Yoshinobu; Shigenobu, Shuji; Watanabe, Dai; Toga, Kouhei; Saiki, Ryota; Shimada, Keisuke; Bourguignon, Thomas; Lo, Nathan; Hojo, Masaru; Maekawa, Kiyoto; Miura, Toru

    2013-01-01

    In termites, division of labor among castes, categories of individuals that perform specialized tasks, increases colony-level productivity and is the key to their ecological success. Although molecular studies on caste polymorphism have been performed in termites, we are far from a comprehensive understanding of the molecular basis of this phenomenon. To facilitate future molecular studies, we aimed to construct expressed sequence tag (EST) libraries covering wide ranges of gene repertoires in three representative termite species, Hodotermopsis sjostedti, Reticulitermes speratus and Nasutitermes takasagoensis. We generated normalized cDNA libraries from whole bodies, except for guts containing microbes, of almost all castes, sexes and developmental stages and sequenced them with the 454 GS FLX titanium system. We obtained >1.2 million quality-filtered reads yielding >400 million bases for each of the three species. Isotigs, which are analogous to individual transcripts, and singletons were produced by assembling the reads and annotated using public databases. Genes related to juvenile hormone, which plays crucial roles in caste differentiation of termites, were identified from the EST libraries by BLAST search. To explore the potential for DNA methylation, which plays an important role in caste differentiation of honeybees, tBLASTn searches for DNA methyltransferases (dnmt1, dnmt2 and dnmt3) and methyl-CpG binding domain (mbd) were performed against the EST libraries. All four of these genes were found in the H. sjostedti library, while all except dnmt3 were found in R. speratus and N. takasagoensis. The ratio of the observed to the expected CpG content (CpG O/E), which is a proxy for DNA methylation level, was calculated for the coding sequences predicted from the isotigs and singletons. In all of the three species, the majority of coding sequences showed depletion of CpG O/E (less than 1), and the distributions of CpG O/E were bimodal, suggesting the presence of

  4. Construction and characterization of normalized cDNA libraries by 454 pyrosequencing and estimation of DNA methylation levels in three distantly related termite species.

    Directory of Open Access Journals (Sweden)

    Yoshinobu Hayashi

    Full Text Available In termites, division of labor among castes, categories of individuals that perform specialized tasks, increases colony-level productivity and is the key to their ecological success. Although molecular studies on caste polymorphism have been performed in termites, we are far from a comprehensive understanding of the molecular basis of this phenomenon. To facilitate future molecular studies, we aimed to construct expressed sequence tag (EST libraries covering wide ranges of gene repertoires in three representative termite species, Hodotermopsis sjostedti, Reticulitermes speratus and Nasutitermes takasagoensis. We generated normalized cDNA libraries from whole bodies, except for guts containing microbes, of almost all castes, sexes and developmental stages and sequenced them with the 454 GS FLX titanium system. We obtained >1.2 million quality-filtered reads yielding >400 million bases for each of the three species. Isotigs, which are analogous to individual transcripts, and singletons were produced by assembling the reads and annotated using public databases. Genes related to juvenile hormone, which plays crucial roles in caste differentiation of termites, were identified from the EST libraries by BLAST search. To explore the potential for DNA methylation, which plays an important role in caste differentiation of honeybees, tBLASTn searches for DNA methyltransferases (dnmt1, dnmt2 and dnmt3 and methyl-CpG binding domain (mbd were performed against the EST libraries. All four of these genes were found in the H. sjostedti library, while all except dnmt3 were found in R. speratus and N. takasagoensis. The ratio of the observed to the expected CpG content (CpG O/E, which is a proxy for DNA methylation level, was calculated for the coding sequences predicted from the isotigs and singletons. In all of the three species, the majority of coding sequences showed depletion of CpG O/E (less than 1, and the distributions of CpG O/E were bimodal, suggesting

  5. 申克孢子丝菌酵母相和菌丝相cDNA消减文库的构建%Construction of cDNA subtractive library for the yeast and mycelium phases of Sporothrix Schenckii

    Institute of Scientific and Technical Information of China (English)

    周汛; 杨致邦; 郭丽媛; 肖异珠

    2011-01-01

    Objective To explore molecular mechanism of dimorphic transition of Sporothrix schenckii, differential gene expression in dimorphic transition of Sporothrix schenckii was screened. Methods cDNA subtractive library for the yeast ( Y ) and mycelium ( M ) phases was constructed by suppression subtractive hybridization ( SSH ) . Bioinformatics analysis was performed to profile the relationship between the differently expressed genes and dimorphic transition. Results 751 ESTs were obtained in M + Y library , with the average length of 690. 98bp. Meanwhile . 875 ESTs were obtained in Y + M library, with the average length of 575. 9bp. After splicing of ESTs,101 unigenes were obtained in M + Y library and 249 unigenes in Y + M library. Some structure genes and function-unknown genes in these differentially expressed genes appeared to be related to dimorphic transition as compared with BLASTN. Conclusion It is evident that the subtracted cDNA library for the dimorphic transition of Sporothrix Schenckii was successfully constructed, thereby providing solid foundation for screening the genes involved the dimorphic transition of Sporothrix schenckii.%目的 筛选与申克孢子丝菌酵母相与菌丝相双相转换相关的差异表达基因,为探讨其双相转换的分子的机制奠定基础.方法 应用抑制性消减杂交技术,构建高特异性的申克孢子丝菌菌丝相(mycelium,M)和酵母相(yeast,Y)的正反cDNA消减文库,并对其差异表达的基因进行生物信息学分析.结果 M+Y文库获得751条表达序列标签,平均长度为690.98 bp,经拼接后获得101条非冗余序列.Y+M文库获得875条表达序列标签,平均长度为575.9 bp,拼接获得249条非冗余序列.经BLASTN比对,这些差异表达基因中,某些结构基因和功能不明的细胞分子类基因可能与双相转换有关.结论 成功构建了高特异性的申克孢子丝菌菌丝相和酵母相的正反cDNA 消减文库,为进一步筛选申克孢子丝菌的双相转换基因奠定了基础.

  6. Gene discovery from Jatropha curcas by sequencing of ESTs from normalized and full-length enriched cDNA library from developing seeds

    Directory of Open Access Journals (Sweden)

    Sugantham Priyanka Annabel

    2010-10-01

    Full Text Available Abstract Background Jatropha curcas L. is promoted as an important non-edible biodiesel crop worldwide. Jatropha oil, which is a triacylglycerol, can be directly blended with petro-diesel or transesterified with methanol and used as biodiesel. Genetic improvement in jatropha is needed to increase the seed yield, oil content, drought and pest resistance, and to modify oil composition so that it becomes a technically and economically preferred source for biodiesel production. However, genetic improvement efforts in jatropha could not take advantage of genetic engineering methods due to lack of cloned genes from this species. To overcome this hurdle, the current gene discovery project was initiated with an objective of isolating as many functional genes as possible from J. curcas by large scale sequencing of expressed sequence tags (ESTs. Results A normalized and full-length enriched cDNA library was constructed from developing seeds of J. curcas. The cDNA library contained about 1 × 106 clones and average insert size of the clones was 2.1 kb. Totally 12,084 ESTs were sequenced to average high quality read length of 576 bp. Contig analysis revealed 2258 contigs and 4751 singletons. Contig size ranged from 2-23 and there were 7333 ESTs in the contigs. This resulted in 7009 unigenes which were annotated by BLASTX. It showed 3982 unigenes with significant similarity to known genes and 2836 unigenes with significant similarity to genes of unknown, hypothetical and putative proteins. The remaining 191 unigenes which did not show similarity with any genes in the public database may encode for unique genes. Functional classification revealed unigenes related to broad range of cellular, molecular and biological functions. Among the 7009 unigenes, 6233 unigenes were identified to be potential full-length genes. Conclusions The high quality normalized cDNA library was constructed from developing seeds of J. curcas for the first time and 7009 unigenes coding

  7. Construction of a cDNA expression library of Suaeda salsa%碱蓬cDNA表达文库的构建

    Institute of Scientific and Technical Information of China (English)

    马秀灵; 王丽萍; 张慧

    2002-01-01

    以盐生植物盐地碱蓬(Suaeda salsa)地上部分为材料,提取植物总RNA,纯化出mRNA,合成cDNA第一链,得到双链cDNA后,连接入植物表达载体,构建cDNA表达文库.该文库重组子约10-6.将该文库转化农杆菌GV3101,可直接用以转化拟南芥.%In order to find new genes related to salt stress,we constructed a Suaeda salsa aerial part tissue cDNA expression library.Halophyte S.salsa was used as plant material,the first strands of cDNAs were synthesized from mRNA.Ligated the cDNAs into the expression vector,then transformed Escherichia.coli.The library titer is about 10-6.Plasmids were extracted from amplified library and were transferred intoAgrobacterium,which subsequently was used to transform Arabidopsis thaliana.

  8. Bacteria-based in vivo peptide library screening using biopanning approach.

    Science.gov (United States)

    Choi, Ji-Hyeon; Park, Sang-Hyun

    2011-10-01

    Traditionally, library screening has been performed to identify biologically active agents including small molecules or peptides that inhibit target proteins or molecules with therapeutic interests. Due to its chemical nature, library screening is usually performed under in vitro environments using purified proteins and molecules. However, active agents identified from in vitro screenings often fail to exhibit biological activities in cells. To overcome this inherent limitation, we have developed an in vivo peptide library screening system that allows for the identification of dissociative inhibitors of protein interactions of interest. The screening is based on the reconstitution of the cI repressor from bacteriophage lambda with high-density expression peptide library and is entirely performed in bacteria cells. Furthermore, to enhance the efficacy and sensitivity of the screening, a multiple-round biopanning approach was employed for amplification and enrichment of positive peptides. Overall, this in vivo screening should provide a fast and efficient tool for identification of biologically active peptide molecules against target protein assembly.

  9. Expressed Sequence Tags Analysis and Design of Simple Sequence Repeats Markers from a Full-Length cDNA Library in Perilla frutescens (L.

    Directory of Open Access Journals (Sweden)

    Eun Soo Seong

    2015-01-01

    Full Text Available Perilla frutescens is valuable as a medicinal plant as well as a natural medicine and functional food. However, comparative genomics analyses of P. frutescens are limited due to a lack of gene annotations and characterization. A full-length cDNA library from P. frutescens leaves was constructed to identify functional gene clusters and probable EST-SSR markers via analysis of 1,056 expressed sequence tags. Unigene assembly was performed using basic local alignment search tool (BLAST homology searches and annotated Gene Ontology (GO. A total of 18 simple sequence repeats (SSRs were designed as primer pairs. This study is the first to report comparative genomics and EST-SSR markers from P. frutescens will help gene discovery and provide an important source for functional genomics and molecular genetic research in this interesting medicinal plant.

  10. Immunoaffinity Ultrafiltration with Ion Spray HPLC/MS for Screening Small-Molecule Libraries.

    Science.gov (United States)

    Wieboldt, R; Zweigenbaum, J; Henion, J

    1997-05-01

    A solution-phase screening method for libraries of pharmaceutically relevant molecules is presented. The technique is applicable to screening combinatorial libraries of 20-30 closely related molecules. In this report, individual benzodiazepines are selected from a multicomponent library mixture by formation in solution of noncovalent immunoaffinity complexes with antibodies raised to therapeutically proven drugs such as nitrazepam, temazepam, or oxazepam. Captured compounds are separated from nonspecifically bound library components by centrifugal ultrafiltration. The specifically selected molecules retained on the filter are subsequently liberated from the antibodies by acidification and analyzed by HPLC coupled with pneumatically assisted electrospray (ion spray) ionization mass spectrometric detection. Competition by the benzodiazepines for limited antibody binding sites is controlled by varying the stoichiometry of the complexation mixture. This procedure selects library components with the greatest affinity for a particular antibody. Specific capture of benzodiazepines is demonstrated by screening both a pool of structurally similar benzodiazepines and a more complex mixture of benzodiazepines with an additional set of unrelated compounds. Affinity ultrafiltration and electrospray mass spectrometry complement each other to enhance screening and identification of pooled drug candidates and potentially can be extended to other small-molecule combinatorial libraries and macromolecular receptor preparations.

  11. Construction of an adult barnacle (Balanus amphitrite cDNA library and selection of reference genes for quantitative RT-PCR studies

    Directory of Open Access Journals (Sweden)

    Burgess J Grant

    2009-06-01

    Full Text Available Abstract Background Balanus amphitrite is a barnacle commonly used in biofouling research. Although many aspects of its biology have been elucidated, the lack of genetic information is impeding a molecular understanding of its life cycle. As part of a wider multidisciplinary approach to reveal the biogenic cues influencing barnacle settlement and metamorphosis, we have sequenced and annotated the first cDNA library for B. amphitrite. We also present a systematic validation of potential reference genes for normalization of quantitative real-time PCR (qRT-PCR data obtained from different developmental stages of this animal. Results We generated a cDNA library containing expressed sequence tags (ESTs from adult B. amphitrite. A total of 609 unique sequences (comprising 79 assembled clusters and 530 singlets were derived from 905 reliable unidirectionally sequenced ESTs. Bioinformatics tools such as BLAST, HMMer and InterPro were employed to allow functional annotation of the ESTs. Based on these analyses, we selected 11 genes to study their ability to normalize qRT-PCR data. Total RNA extracted from 7 developmental stages was reverse transcribed and the expression stability of the selected genes was compared using geNorm, BestKeeper and NormFinder. These software programs produced highly comparable results, with the most stable gene being mt-cyb, while tuba, tubb and cp1 were clearly unsuitable for data normalization. Conclusion The collection of B. amphitrite ESTs and their annotation has been made publically available representing an important resource for both basic and applied research on this species. We developed a qRT-PCR assay to determine the most reliable reference genes. Transcripts encoding cytochrome b and NADH dehydrogenase subunit 1 were expressed most stably, although other genes also performed well and could prove useful to normalize gene expression studies.

  12. Selecting, Acquiring, and Using Small Molecule Libraries for High-Throughput Screening.

    Science.gov (United States)

    Dandapani, Sivaraman; Rosse, Gerard; Southall, Noel; Salvino, Joseph M; Thomas, Craig J

    The selection, acquisition and use of high quality small molecule libraries for screening is an essential aspect of drug discovery and chemical biology programs. Screening libraries continue to evolve as researchers gain a greater appreciation of the suitability of small molecules for specific biological targets, processes and environments. The decisions surrounding the make-up of any given small molecule library is informed by a multitude of variables and opinions vary on best-practices. The fitness of any collection relies upon upfront filtering to avoiding problematic compounds, assess appropriate physicochemical properties, install the ideal level of structural uniqueness and determine the desired extent of molecular complexity. These criteria are under constant evaluation and revision as academic and industrial organizations seek out collections that yield ever improving results from their screening portfolios. Practical questions including cost, compound management, screening sophistication and assay objective also play a significant role in the choice of library composition. This overview attempts to offer advice to all organizations engaged in small molecule screening based upon current best practices and theoretical considerations in library selection and acquisition.

  13. Quantitative screening of yeast surface-displayed polypeptide libraries by magnetic bead capture.

    Science.gov (United States)

    Yeung, Yik A; Wittrup, K Dane

    2002-01-01

    Magnetic bead capture is demonstrated here to be a feasible alternative for quantitative screening of favorable mutants from a cell-displayed polypeptide library. Flow cytometric sorting with fluorescent probes has been employed previously for high throughput screening for either novel binders or improved mutants. However, many laboratories do not have ready access to this technology as a result of the limited availability and high cost of cytometers, restricting the use of cell-displayed libraries. Using streptavidin-coated magnetic beads and biotinylated ligands, an alternative approach to cell-based library screening for improved mutants was developed. Magnetic bead capture probability of labeled cells is shown to be closely correlated with the surface ligand density. A single-pass enrichment ratio of 9400 +/- 1800-fold, at the expense of 85 +/- 6% binder losses, is achieved from screening a library that contains one antibody-displaying cell (binder) in 1.1 x 10(5) nondisplaying cells. Additionally, kinetic screening for an initial high affinity to low affinity (7.7-fold lower) mutant ratio of 1:95,000, the magnetic bead capture method attains a single-pass enrichment ratio of 600 +/- 200-fold with a 75 +/- 24% probability of loss for the higher affinity mutant. The observed high loss probabilities can be straightforwardly compensated for by library oversampling, given the inherently parallel nature of the screen. Overall, these results demonstrate that magnetic beads are capable of quantitatively screening for novel binders and improved mutants. The described methods are directly analogous to procedures in common use for phage display and should lower the barriers to entry for use of cell surface display libraries.

  14. Yeast surface display for screening combinatorial polypeptide libraries.

    Science.gov (United States)

    Boder, E T; Wittrup, K D

    1997-06-01

    Display on the yeast cell wall is well suited for engineering mammalian cell-surface and secreted proteins (e.g., antibodies, receptors, cytokines) that require endoplasmic reticulum-specific post-translational processing for efficient folding and activity. C-terminal fusion to the Aga2p mating adhesion receptor of Saccharomyces cerevisiae has been used for the selection of scFv antibody fragments with threefold decreased antigen dissociation rate from a randomly mutated library. A eukaryotic host should alleviate expression biases present in bacterially propagated combinatorial libraries. Quantitative flow cytometric analysis enables fine discrimination of kinetic parameters for protein binding to soluble ligands.

  15. Reducing codon redundancy and screening effort of combinatorial protein libraries created by saturation mutagenesis.

    Science.gov (United States)

    Kille, Sabrina; Acevedo-Rocha, Carlos G; Parra, Loreto P; Zhang, Zhi-Gang; Opperman, Diederik J; Reetz, Manfred T; Acevedo, Juan Pablo

    2013-02-15

    Saturation mutagenesis probes define sections of the vast protein sequence space. However, even if randomization is limited this way, the combinatorial numbers problem is severe. Because diversity is created at the codon level, codon redundancy is a crucial factor determining the necessary effort for library screening. Additionally, due to the probabilistic nature of the sampling process, oversampling is required to ensure library completeness as well as a high probability to encounter all unique variants. Our trick employs a special mixture of three primers, creating a degeneracy of 22 unique codons coding for the 20 canonical amino acids. Therefore, codon redundancy and subsequent screening effort is significantly reduced, and a balanced distribution of codon per amino acid is achieved, as demonstrated exemplarily for a library of cyclohexanone monooxygenase. We show that this strategy is suitable for any saturation mutagenesis methodology to generate less-redundant libraries.

  16. Expression of heterologous sigma factors enables functional screening of metagenomic and heterologous genomic libraries.

    Science.gov (United States)

    Gaida, Stefan M; Sandoval, Nicholas R; Nicolaou, Sergios A; Chen, Yili; Venkataramanan, Keerthi P; Papoutsakis, Eleftherios T

    2015-05-06

    A key limitation in using heterologous genomic or metagenomic libraries in functional genomics and genome engineering is the low expression of heterologous genes in screening hosts, such as Escherichia coli. To overcome this limitation, here we generate E. coli strains capable of recognizing heterologous promoters by expressing heterologous sigma factors. Among seven sigma factors tested, RpoD from Lactobacillus plantarum (Lpl) appears to be able of initiating transcription from all sources of DNA. Using the promoter GFP-trap concept, we successfully screen several heterologous and metagenomic DNA libraries, thus enlarging the genomic space that can be functionally sampled in E. coli. For an application, we show that screening fosmid-based Lpl genomic libraries in an E. coli strain with a chromosomally integrated Lpl rpoD enables the identification of Lpl genetic determinants imparting strong ethanol tolerance in E. coli. Transcriptome analysis confirms increased expression of heterologous genes in the engineered strain.

  17. High-content screening of yeast mutant libraries by shotgun lipidomics

    DEFF Research Database (Denmark)

    Tarasov, Kirill; Stefanko, Adam; Casanovas, Albert;

    2014-01-01

    To identify proteins with a functional role in lipid metabolism and homeostasis we designed a high-throughput platform for high-content lipidomic screening of yeast mutant libraries. To this end, we combined culturing and lipid extraction in 96-well format, automated direct infusion nanoelectrosp......To identify proteins with a functional role in lipid metabolism and homeostasis we designed a high-throughput platform for high-content lipidomic screening of yeast mutant libraries. To this end, we combined culturing and lipid extraction in 96-well format, automated direct infusion...... factor KAR4 precipitated distinct lipid metabolic phenotypes. These results demonstrate that the high-throughput shotgun lipidomics platform is a valid and complementary proxy for high-content screening of yeast mutant libraries....

  18. Identification of genes up-regulated in dedifferentiating Nicotania glauca pith tissue, using an improved method for constructing a subtractive cDNA library.

    Science.gov (United States)

    Cecchini, E; Dominy, P J; Geri, C; Kaiser, K; Sentry, J; Milner, J J

    1993-12-11

    Pith explants of Nicotiana glauca grown in vitro in synthetic medium supplemented with 2,4 dichlorophenoxyacetic acid (2, 4 D), are induced to dedifferentiate. Treatment with actinomycin D within the first 4-8 h of culture (but not later) is lethal and the explants die, implying a requirement for de novo transcription. The genes expressed during the initial period of culture are presumably critical for subsequent cell survival and proliferation, but so far their identity is unknown. We have constructed a subtractive cDNA library, enriched in sequences more abundant in dedifferentiating tissue than in pith. The subtractive library contains approximately seven major species, two of which, NGSUB7 and NGSUB8, are highly abundant. In Northern blots, these two hybridized to mRNA species whose abundance increased significantly but transiently during the first 4 to 8 h of culture. The sequence of NGSUB7 showed no significant homology at a nucleotide or derived amino acid level with any previously reported sequence. NGSUB8 however, showed significant homology over part of the derived amino acid sequence to several yeast and bacterial proteins with DNA binding function. We propose that the two recombinants represent transcripts from two novel genes edeA and edeB, which are expressed early in dedifferentiation.

  19. Development and characterization of a high temperature stress responsive subtractive cDNA library in Pearl Millet Pennisetum glaucum (L.) R.Br.

    Science.gov (United States)

    James, Donald; Tarafdar, Avijit; Biswas, Koushik; Sathyavathi, Tara C; Padaria, Jasdeep Chatrath; Kumar, P Ananda

    2015-08-01

    Pearl millet (Pennisetum glaucum L. R. Br.) is an important cereal crop grown mainly in the arid and semi-arid regions of India known to possess the natural ability to withstand thermal stress. To elucidate the molecular basis of high temperature response in pearl millet, 12 days old seedlings of P. glaucum cv. 841A were subjected to heat stress at 46 degrees C for different time durations ( 30 min, 2, 4, 8, 12 and 24 h) and a forward subtractive cDNA library was constructed from pooled RNA of heat stressed seedlings. A total of 331 high quality Expressed Sequence Tags (ESTs) were obtained from randomly selected 1050 clones. Sequences were assembled into 103 unique sequences consisting of 37 contigs and 66 singletons. Of these, 92 unique sequences were submitted to NCBI dbEST database. Gene Ontology through RGAP data base and BLASTx analysis revealed that about 18% of the ESTs showed homology to genes for "response to abiotic and biotic stimulus". About 2% of the ESTs showed no homology with genes in dbEST, indicating the presence of uncharacterized candidate genes involved in heat stress response in P. glaucum. Differential expression of selected genes (hsp101 and CRT) from the SSH library were validated by qRT-PCR analysis. The ESTs thus generated are a rich source of heat stress responsive genes, which can be utilized in improving thermotolerance of other food crops.

  20. Chemiluminescent detection of sequential DNA hybridizations to high-density, filter-arrayed cDNA libraries: a subtraction method for novel gene discovery.

    Science.gov (United States)

    Guiliano, D; Ganatra, M; Ware, J; Parrot, J; Daub, J; Moran, L; Brennecke, H; Foster, J M; Supali, T; Blaxter, M; Scott, A L; Williams, S A; Slatko, B E

    1999-07-01

    A chemiluminescent approach for sequential DNA hybridizations to high-density filter arrays of cDNAs, using a biotin-based random priming method followed by a streptavidin/alkaline phosphatase/CDP-Star detection protocol, is presented. The method has been applied to the Brugia malayi genome project, wherein cDNA libraries, cosmid and bacterial artificial chromosome (BAC) libraries have been gridded at high density onto nylon filters for subsequent analysis by hybridization. Individual probes and pools of rRNA probes, ribosomal protein probes and expressed sequence tag probes show correct specificity and high signal-to-noise ratios even after ten rounds of hybridization, detection, stripping of the probes from the membranes and rehybridization with additional probe sets. This approach provides a subtraction method that leads to a reduction in redundant DNA sequencing, thus increasing the rate of novel gene discovery. The method is also applicable for detecting target sequences, which are present in one or only a few copies per cell; it has proven useful for physical mapping of BAC and cosmid high-density filter arrays, wherein multiple probes have been hybridized at one time (multiplexed) and subsequently "deplexed" into individual components for specific probe localizations.

  1. Automated screening for small organic ligands using DNA-encoded chemical libraries.

    Science.gov (United States)

    Decurtins, Willy; Wichert, Moreno; Franzini, Raphael M; Buller, Fabian; Stravs, Michael A; Zhang, Yixin; Neri, Dario; Scheuermann, Jörg

    2016-04-01

    DNA-encoded chemical libraries (DECLs) are collections of organic compounds that are individually linked to different oligonucleotides, serving as amplifiable identification barcodes. As all compounds in the library can be identified by their DNA tags, they can be mixed and used in affinity-capture experiments on target proteins of interest. In this protocol, we describe the screening process that allows the identification of the few binding molecules within the multiplicity of library members. First, the automated affinity selection process physically isolates binding library members. Second, the DNA codes of the isolated binders are PCR-amplified and subjected to high-throughput DNA sequencing. Third, the obtained sequencing data are evaluated using a C++ program and the results are displayed using MATLAB software. The resulting selection fingerprints facilitate the discrimination of binding from nonbinding library members. The described procedures allow the identification of small organic ligands to biological targets from a DECL within 10 d.

  2. Peptide substrate identification for yeast Hsp40 Ydj1 by screening the phage display library

    Directory of Open Access Journals (Sweden)

    Li Jingzhi

    2004-01-01

    Full Text Available We have identified a peptide substrate for molecular chaperone Hsp40 Ydj1 by utilizing the combination of phage display library screening and isothemol titration calirimetry (ITC. The initial peptide substrate screening for Hsp40 Ydj1 has been carried out by utilizing a 7-mer phage display library. The peptide sequences from the bio-panning were synthesized and object to the direct affinity measurement for Hsp40 Ydj1 by isothemol titration calirimetry studies. The peptide which has the measurable affinity with Ydj1 shows enriched hydrophobic residues in the middle of the substrate fragment. The peptide substrate specificity for molecular chaperone Hsp40 has been analyzed.

  3. Construction of a Metagenomic DNA Library of Sponge Symbionts and Screening of Antibacterial Metabolites

    Institute of Scientific and Technical Information of China (English)

    CHEN Juan; ZHU Tianjiao; LI Dehai; CUI Chengbin; FANG Yuchun; LIU Hongbing; LIU Peipei; GU Qianqun; ZHU Weiming

    2006-01-01

    To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DH5α and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.

  4. Next-generation libraries for robust RNA interference-based genome-wide screens.

    Science.gov (United States)

    Kampmann, Martin; Horlbeck, Max A; Chen, Yuwen; Tsai, Jordan C; Bassik, Michael C; Gilbert, Luke A; Villalta, Jacqueline E; Kwon, S Chul; Chang, Hyeshik; Kim, V Narry; Weissman, Jonathan S

    2015-06-30

    Genetic screening based on loss-of-function phenotypes is a powerful discovery tool in biology. Although the recent development of clustered regularly interspaced short palindromic repeats (CRISPR)-based screening approaches in mammalian cell culture has enormous potential, RNA interference (RNAi)-based screening remains the method of choice in several biological contexts. We previously demonstrated that ultracomplex pooled short-hairpin RNA (shRNA) libraries can largely overcome the problem of RNAi off-target effects in genome-wide screens. Here, we systematically optimize several aspects of our shRNA library, including the promoter and microRNA context for shRNA expression, selection of guide strands, and features relevant for postscreen sample preparation for deep sequencing. We present next-generation high-complexity libraries targeting human and mouse protein-coding genes, which we grouped into 12 sublibraries based on biological function. A pilot screen suggests that our next-generation RNAi library performs comparably to current CRISPR interference (CRISPRi)-based approaches and can yield complementary results with high sensitivity and high specificity.

  5. Systems analysis of quantitative shRNA-library screens identifies regulators of cell adhesion

    Directory of Open Access Journals (Sweden)

    Huang XiaoDong

    2008-06-01

    Full Text Available Abstract Background High throughput screens with RNA interference technology enable loss-of-function analyses of gene activities in mammalian cells. While the construction of genome-scale shRNA libraries has been successful, results of large-scale screening of those libraries can be difficult to analyze because of the relatively high noise levels and the fact that not all shRNAs in a library are equally effective in silencing gene expression. Results We have screened a library consisting of 43,828 shRNAs directed against 8,500 human genes for functions that are necessary in cell detachment induced by a constitutively activated c-Abl tyrosine kinase. To deal with the issues of noise and uncertainty of knockdown efficiencies, we employed an analytical strategy that combines quantitative data analysis with biological knowledge, i.e. Gene Ontology and pathway information, to increase the power of the RNAi screening technique. Using this strategy we found 16 candidate genes to be involved in Abl-induced disruption of cell adhesion, and verified that the knockdown of IL6ST is associated with enhanced cell attachment. Conclusion Our results suggest that the power of genome-wide quantitative shRNA screens can be significantly increased when analyzed using a systems biology-based approach to identify functional gene networks.

  6. Antibacterial enzymes from the functional screening of metagenomic libraries hosted in Ralstonia metallidurans.

    Science.gov (United States)

    Iqbal, Hala A; Craig, Jeffrey W; Brady, Sean F

    2014-05-01

    Phenotype-based screening of bacterial metagenomic libraries provides an avenue for the discovery of novel genes, enzymes, and metabolites that have a variety of potential clinical and industrial uses. Here, we report the identification of a functionally diverse collection of antibacterially active enzymes from the phenotypic screening of 700 000 cosmid clones prepared from Arizona soil DNA and hosted in Ralstonia metallidurans. Environmental DNA clones surrounded by zones of growth inhibition in a bacterial overlay assay were found, through bioinformatics and functional analyses, to encode enzymes with predicted peptidase, lipase, and glycolytic activities conferring antibiosis. The antibacterial activities observed in our R. metallidurans-based assay could not be replicated with the same clones in screens using Escherichia coli as a heterologous host, suggesting that the large-scale screening of metagenomic libraries for antibiosis using phylogenetically diverse hosts should be a productive strategy for identifying enzymes with functionally diverse antibacterial activities.

  7. Construction and characterization of a yeast two-hybrid cDNA library from a FAT10-overexpressing human hepatic carcinoma cell line Hep3B%类泛素FAT10高表达肝癌细胞株Hep3B酵母双杂交cDNA文库的构建

    Institute of Scientific and Technical Information of China (English)

    余新; 刘天; 德洪波; 李国惠; 邵江华

    2011-01-01

    AIM: To construct a yeast two-hybrid cDNA library from a FAT10-overexpressing human hepatic carcinoma cell line Hep3B.METHODS: Total RNA was prepared from Hep3B cells and used to purify poly (A) mRNA.Double-stranded cDNA was synthesized from the purified mRNA, ligated to EcoR Ⅰ adaptor,digested with EcoR Ⅰ/Xho Ⅰ enzymes, and then cloned into the pGADT7 vector.The recombinant vector was transformed into E.coli DH10B to obtain a primary cDNA library.The primary library was amplified and used to determine the size of cDNA inserts through enzyme digestion.RESULTS: The primary cDNA library contained 1.03 × 106independent clones.The titer of the cDNA library was estimated to be 2.50 × 106 cfu/mL, and that of the amplified library was 3.60 × 109 cfu/mL.The size of the inserts varied from 0.5 to 3.5 kb, with an average value of about 2.0 kb.CONCLUSION: A yeast two-hybrid cDNA library has been successfully generated from FAT10-over-expressing Hep3B ceils and can be used for future screening of proteins interacting with FAT10.%目的:构建类泛素FAT10高表达肝癌细胞株Hep3B的酵母双杂交用cDNA文库.方法:从肝癌细胞Hep3B中提取总RNA,分离mRNA.利用反转录酶M-MLV与Oligo(dT)AnchorPrimer合成1 Strand cDNA,用E.coli DNAPolymerase与E.coli DNA Ligase将RNA链置换成DNA链,合成2 Strand cDNA.将双链cDNA与EcoR Ⅰ Adaptor连接,然后用EcoR Ⅰ /Xho Ⅰ进行酶切.使用Spin Column除去短链cDNA与pGADT7载体连接,转化入E.coli DH10B,建成原始文库.然后对其进行扩增并随机挑取单菌落,酶切鉴定重组子插入片段大小.结果:提取的总RNA降解少且分子完整;RNA纯度高,相对分子质量为400-5000 bp;成功合成双链cDNA,均符合建库要求:库容量达到1.03×10克隆,原始文库滴度为2.50×10 cfu/L,扩增后的文库滴度为3.60×10 cfu/L.插入片段大小分布为0.5-3.5 kb,平均长度约为2.0 kb.结论:所构建文库的各项指标均达到要求,为筛选FAT10作用蛋白奠定了重要基础.

  8. Efficient Management of High-Throughput Screening Libraries with SAVANAH

    DEFF Research Database (Denmark)

    List, Markus; Elnegaard, Marlene Pedersen; Schmidt, Steffen;

    2016-01-01

    High-throughput screening (HTS) has become an indispensable tool for the pharmaceutical industry and for biomedical research. A high degree of automation allows for experiments in the range of a few hundred up to several hundred thousand to be performed in close succession. The basis for such scr...

  9. Construction and Evaluation of Normalized cDNA Libraries Enriched with Full-Length Sequences for Rapid Discovery of New Genes from Sisal (Agave sisalana Perr.) Different Developmental Stages

    Science.gov (United States)

    Zhou, Wen-Zhao; Zhang, Yan-Mei; Lu, Jun-Ying; Li, Jun-Feng

    2012-01-01

    To provide a resource of sisal-specific expressed sequence data and facilitate this powerful approach in new gene research, the preparation of normalized cDNA libraries enriched with full-length sequences is necessary. Four libraries were produced with RNA pooled from Agave sisalana multiple tissues to increase efficiency of normalization and maximize the number of independent genes by SMART™ method and the duplex-specific nuclease (DSN). This procedure kept the proportion of full-length cDNAs in the subtracted/normalized libraries and dramatically enhanced the discovery of new genes. Sequencing of 3875 cDNA clones of libraries revealed 3320 unigenes with an average insert length about 1.2 kb, indicating that the non-redundancy of libraries was about 85.7%. These unigene functions were predicted by comparing their sequences to functional domain databases and extensively annotated with Gene Ontology (GO) terms. Comparative analysis of sisal unigenes and other plant genomes revealed that four putative MADS-box genes and knotted-like homeobox (knox) gene were obtained from a total of 1162 full-length transcripts. Furthermore, real-time PCR showed that the characteristics of their transcripts mainly depended on the tight expression regulation of a number of genes during the leaf and flower development. Analysis of individual library sequence data indicated that the pooled-tissue approach was highly effective in discovering new genes and preparing libraries for efficient deep sequencing. PMID:23202944

  10. Construction and evaluation of normalized cDNA libraries enriched with full-length sequences for rapid discovery of new genes from Sisal (Agave sisalana Perr.) different developmental stages.

    Science.gov (United States)

    Zhou, Wen-Zhao; Zhang, Yan-Mei; Lu, Jun-Ying; Li, Jun-Feng

    2012-10-12

    To provide a resource of sisal-specific expressed sequence data and facilitate this powerful approach in new gene research, the preparation of normalized cDNA libraries enriched with full-length sequences is necessary. Four libraries were produced with RNA pooled from Agave sisalana multiple tissues to increase efficiency of normalization and maximize the number of independent genes by SMART™ method and the duplex-specific nuclease (DSN). This procedure kept the proportion of full-length cDNAs in the subtracted/normalized libraries and dramatically enhanced the discovery of new genes. Sequencing of 3875 cDNA clones of libraries revealed 3320 unigenes with an average insert length about 1.2 kb, indicating that the non-redundancy of libraries was about 85.7%. These unigene functions were predicted by comparing their sequences to functional domain databases and extensively annotated with Gene Ontology (GO) terms. Comparative analysis of sisal unigenes and other plant genomes revealed that four putative MADS-box genes and knotted-like homeobox (knox) gene were obtained from a total of 1162 full-length transcripts. Furthermore, real-time PCR showed that the characteristics of their transcripts mainly depended on the tight expression regulation of a number of genes during the leaf and flower development. Analysis of individual library sequence data indicated that the pooled-tissue approach was highly effective in discovering new genes and preparing libraries for efficient deep sequencing.

  11. The venom gland transcriptome of Latrodectus tredecimguttatus revealed by deep sequencing and cDNA library analysis.

    Directory of Open Access Journals (Sweden)

    Quanze He

    Full Text Available Latrodectus tredecimguttatus, commonly known as black widow spider, is well known for its dangerous bite. Although its venom has been characterized extensively, some fundamental questions about its molecular composition remain unanswered. The limited transcriptome and genome data available prevent further understanding of spider venom at the molecular level. In the present study, we combined next-generation sequencing and conventional DNA sequencing to construct a venom gland transcriptome of the spider L. tredecimguttatus, which resulted in the identification of 9,666 and 480 high-confidence proteins among 34,334 de novo sequences and 1,024 cDNA sequences, respectively, by assembly, translation, filtering, quantification and annotation. Extensive functional analyses of these proteins indicated that mRNAs involved in RNA transport and spliceosome, protein translation, processing and transport were highly enriched in the venom gland, which is consistent with the specific function of venom glands, namely the production of toxins. Furthermore, we identified 146 toxin-like proteins forming 12 families, including 6 new families in this spider in which α-LTX-Lt1a family2 is firstly identified as a subfamily of α-LTX-Lt1a family. The toxins were classified according to their bioactivities into five categories that functioned in a coordinate way. Few ion channels were expressed in venom gland cells, suggesting a possible mechanism of protection from the attack of their own toxins. The present study provides a gland transcriptome profile and extends our understanding of the toxinome of spiders and coordination mechanism for toxin production in protein expression quantity.

  12. A library screening approach identifies naturally occurring RNA sequences for a G-quadruplex binding ligand.

    Science.gov (United States)

    Mirihana Arachchilage, Gayan; Morris, Mark J; Basu, Soumitra

    2014-02-07

    An RNA G-quadruplex library was synthesised and screened against kanamycin A as the ligand. Naturally occurring G-quadruplex forming sequences that differentially bind to kanamycin A were identified and characterized. This provides a simple and effective strategy for identification of potential intracellular G-quadruplex targets for a ligand.

  13. Bacillus subtilis as a tool for screening soil metagenomic libraries for antimicrobial activities.

    Science.gov (United States)

    Biver, Sophie; Steels, Sébastien; Portetelle, Daniel; Vandenbol, Micheline

    2013-06-28

    Finding new antimicrobial activities by functional metagenomics has been shown to depend on the heterologous host used to express the foreign DNA. Therefore, efforts are devoted to developing new tools for constructing metagenomic libraries in shuttle vectors replicatable in phylogenetically distinct hosts. Here we evaluated the use of the Escherichia coli-Bacillus subtilis shuttle vector pHT01 to construct a forest-soil metagenomic library. This library was screened in both hosts for antimicrobial activities against four opportunistic bacteria: Proteus vulgaris, Bacillus cereus, Staphylococcus epidermidis, and Micrococcus luteus. A new antibacterial activity against B. cereus was found upon screening in B. subtilis. The new antimicrobial agent, sensitive to proteinase K, was not active when the corresponding DNA fragment was expressed in E. coli. Our results validate the use of pHT01 as a shuttle vector and B. subtilis as a host to isolate new activities by functional metagenomics.

  14. Whitefly (Bemisia tabaci genome project: analysis of sequenced clones from egg, instar, and adult (viruliferous and non-viruliferous cDNA libraries

    Directory of Open Access Journals (Sweden)

    Czosnek Henryk

    2006-04-01

    Full Text Available Abstract Background The past three decades have witnessed a dramatic increase in interest in the whitefly Bemisia tabaci, owing to its nature as a taxonomically cryptic species, the damage it causes to a large number of herbaceous plants because of its specialized feeding in the phloem, and to its ability to serve as a vector of plant viruses. Among the most important plant viruses to be transmitted by B. tabaci are those in the genus Begomovirus (family, Geminiviridae. Surprisingly, little is known about the genome of this whitefly. The haploid genome size for male B. tabaci has been estimated to be approximately one billion bp by flow cytometry analysis, about five times the size of the fruitfly Drosophila melanogaster. The genes involved in whitefly development, in host range plasticity, and in begomovirus vector specificity and competency, are unknown. Results To address this general shortage of genomic sequence information, we have constructed three cDNA libraries from non-viruliferous whiteflies (eggs, immature instars, and adults and two from adult insects that fed on tomato plants infected by two geminiviruses: Tomato yellow leaf curl virus (TYLCV and Tomato mottle virus (ToMoV. In total, the sequence of 18,976 clones was determined. After quality control, and removal of 5,542 clones of mitochondrial origin 9,110 sequences remained which included 3,843 singletons and 1,017 contigs. Comparisons with public databases indicated that the libraries contained genes involved in cellular and developmental processes. In addition, approximately 1,000 bases aligned with the genome of the B. tabaci endosymbiotic bacterium Candidatus Portiera aleyrodidarum, originating primarily from the egg and instar libraries. Apart from the mitochondrial sequences, the longest and most abundant sequence encodes vitellogenin, which originated from whitefly adult libraries, indicating that much of the gene expression in this insect is directed toward the production

  15. Fully automatized high-throughput enzyme library screening using a robotic platform.

    Science.gov (United States)

    Dörr, Mark; Fibinger, Michael P C; Last, Daniel; Schmidt, Sandy; Santos-Aberturas, Javier; Böttcher, Dominique; Hummel, Anke; Vickers, Clare; Voss, Moritz; Bornscheuer, Uwe T

    2016-07-01

    A fully automatized robotic platform has been established to facilitate high-throughput screening for protein engineering purposes. This platform enables proper monitoring and control of growth conditions in the microtiter plate format to ensure precise enzyme production for the interrogation of enzyme mutant libraries, protein stability tests and multiple assay screenings. The performance of this system has been exemplified for four enzyme classes important for biocatalysis such as Baeyer-Villiger monooxygenase, transaminase, dehalogenase and acylase in the high-throughput screening of various mutant libraries. This allowed the identification of novel enzyme variants in a sophisticated and highly reliable manner. Furthermore, the detailed optimization protocols should enable other researchers to adapt and improve their methods. Biotechnol. Bioeng. 2016;113: 1421-1432. © 2016 Wiley Periodicals, Inc.

  16. Phage display library screening for identification of interacting protein partners.

    Science.gov (United States)

    Addepalli, Balasubrahmanyam; Rao, Suryadevara; Hunt, Arthur G

    2015-01-01

    Phage display is a versatile high-throughput screening method employed to understand and improve the chemical biology, be it production of human monoclonal antibodies or identification of interacting protein partners. A majority of cell proteins operate in a concerted fashion either by stable or transient interactions. Such interactions can be mediated by recognition of small amino acid sequence motifs on the protein surface. Phage display can play a crucial role in identification of such motifs. This report describes the use of phage display for the identification of high affinity sequence motifs that could be responsible for interactions with a target (bait) protein.

  17. Phylogeny-function analysis of (meta)genomic libraries: screening for expression of ribosomal RNA genes by large-insert library fluorescent in situ hybridization (LIL-FISH)

    NARCIS (Netherlands)

    Leveau, J.H.J.; Gerards, S.; De Boer, W.; Van Veen, J.A.

    2004-01-01

    We assessed the utility of fluorescent in situ hybridization (FISH) in the screening of clone libraries of (meta)genomic or environmental DNA for the presence and expression of bacterial ribosomal RNA (rRNA) genes. To establish proof-of-principle, we constructed a fosmid-based library in Escherichia

  18. Generation and analysis of expressed sequence tags from a normalized cDNA library of young leaf from Ma bamboo (Dendrocalamus latiflorus Munro).

    Science.gov (United States)

    Gao, Z M; Li, C L; Peng, Z H

    2011-11-01

    Ma bamboo (Dendrocalamus latiflorus Munro) belongs to Dendrocalamus genus, Bambusease tribe, Bambusoideae subfamily, Poaceae family. It is a representative species of clumping bamboo, and a principal commercial species for various construction purposes using mature culms and for human consumption using young shoots. A normalized cDNA library was constructed from young leaves of Ma bamboo and 9,574 high-quality ESTs were generated, from which 5,317 unigenes including 1,502 contigs and 3,815 singletons were assembled. The unigenes were assigned into different gene ontology (GO) categories and summarized into 13 broad biologically functional groups according to similar functional characteristics or cellular roles by BLAST search against public databases. Eight hundred and ninety-one unigenes were assigned by KO identifiers and mapped to six KEGG biochemical pathways. The transcripts involved in biosynthesis of secondary metabolites such as cytochrome 450, flavonol synthase/flavanone 3-hydroxylase, and dihydroflavonol-4-reductase were well represented by 14 unigenes in the unigene set. The candidate genes involved in phytohormone metabolism, signal transduction and encoding cell wall-associated receptor kinases were also identified. Sixty-seven unigenes related to plant resistance (R) genes, including RPP genes, RGAs and RDL/RF genes, were discovered. These results will provide genome-wide knowledge about the molecular physiology of Ma bamboo young leaves and tools for advanced studies of molecular mechanism underlying leaf growth and development.

  19. Construction and analysis of the cDNA subtraction library of yeast and mycelial phases of Sporothrix globosa isolated in China: identification of differentially expressed genes*

    Science.gov (United States)

    Hu, Qing-bi; He, Yu; Zhou, Xun

    2015-01-01

    Species included in the Sporothrix schenckii complex are temperature-dependent with dimorphic growth and cause sporotrichosis that is characterized by chronic and fatal lymphocutaneous lesions. The putative species included in the Sporothrix complex are S. brasiliensis, S. globosa, S. mexicana, S. pallida, S. schenckii, and S. lurei. S. globosa is the causal agent of sporotrichosis in China, and its pathogenicity appears to be closely related to the dimorphic transition, i.e. from the mycelial to the yeast phase, it adapts to changing environmental conditions. To determine the molecular mechanisms of the switching process that mediates the dimorphic transition of S. globosa, suppression subtractive hybridization (SSH) was used to prepare a complementary DNA (cDNA) subtraction library from the yeast and mycelial phases. Bioinformatics analysis was performed to profile the relationship between differently expressed genes and the dimorphic transition. Two genes that were expressed at higher levels by the yeast form were selected, and their differential expression levels were verified using a quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR). It is believed that these differently expressed genes are involved in the pathogenesis of S. globosa infection in China. PMID:26642182

  20. Construction and analysis of the cDNA subtraction library of yeast and mycelial phases of Sporothrix globosa isolated in China: identification of differentially expressed genes.

    Science.gov (United States)

    Hu, Qing-bi; He, Yu; Zhou, Xun

    2015-12-01

    Species included in the Sporothrix schenckii complex are temperature-dependent with dimorphic growth and cause sporotrichosis that is characterized by chronic and fatal lymphocutaneous lesions. The putative species included in the Sporothrix complex are S. brasiliensis, S. globosa, S. mexicana, S. pallida, S. schenckii, and S. lurei. S. globosa is the causal agent of sporotrichosis in China, and its pathogenicity appears to be closely related to the dimorphic transition, i.e. from the mycelial to the yeast phase, it adapts to changing environmental conditions. To determine the molecular mechanisms of the switching process that mediates the dimorphic transition of S. globosa, suppression subtractive hybridization (SSH) was used to prepare a complementary DNA (cDNA) subtraction library from the yeast and mycelial phases. Bioinformatics analysis was performed to profile the relationship between differently expressed genes and the dimorphic transition. Two genes that were expressed at higher levels by the yeast form were selected, and their differential expression levels were verified using a quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR). It is believed that these differently expressed genes are involved in the pathogenesis of S. globosa infection in China.

  1. Construction and analysis of an SSH cDNA library of early heat-induced genes of Vigna aconitifolia variety RMO-40.

    Science.gov (United States)

    Rampuria, Sakshi; Joshi, Uma; Palit, Paramita; Deokar, Amit A; Meghwal, Raju R; Mohapatra, T; Srinivasan, R; Bhatt, K V; Sharma, Ramavtar

    2012-11-01

    Moth bean ( Vigna aconitifolia (Jacq.) Marechal) is an important grain legume crop grown in rain fed areas of hot desert regions of Thar, India, under scorching sun rays with very little supplementation of water. An SSH cDNA library was generated from leaf tissues of V. aconitifolia var. RMO-40 exposed to an elevated temperature of 42 °C for 5 min to identify early-induced genes. A total of 488 unigenes (114 contigs and 374 singletons) were derived by cluster assembly and sequence alignment of 738 ESTs; out of 206 ESTs (28%) of unknown proteins, 160 ESTs (14%) were found to be novel to moth bean. Only 578 ESTs (78%) showed significant BLASTX similarity (<1 × 10(-6)) in the NCBI non-redundant database. Gene ontology functional classification terms were retrieved for 479 (65%) sequences, and 339 sequences were annotated with 165 EC codes and mapped to 68 different KEGG pathways. Four hundred and fifty-two ESTs were further annotated with InterProScan (IPS), and no IPS was assigned to 153 ESTs. In addition, the expression level of 27 ESTs in response to heat stress was evaluated through semiquantitative RT-PCR assay. Approximately 20 different signaling genes and 16 different transcription factors have been shown to be associated with heat stress in moth bean for the first time.

  2. A combined de novo protein sequencing and cDNA library approach to the venomic analysis of Chinese spider Araneus ventricosus.

    Science.gov (United States)

    Duan, Zhigui; Cao, Rui; Jiang, Liping; Liang, Songping

    2013-01-14

    In past years, spider venoms have attracted increasing attention due to their extraordinary chemical and pharmacological diversity. The recently popularized proteomic method highly improved our ability to analyze the proteins in the venom. However, the lack of information about isolated venom proteins sequences dramatically limits the ability to confidently identify venom proteins. In the present paper, the venom from Araneus ventricosus was analyzed using two complementary approaches: 2-DE/Shotgun-LC-MS/MS coupled to MASCOT search and 2-DE/Shotgun-LC-MS/MS coupled to manual de novo sequencing followed by local venom protein database (LVPD) search. The LVPD was constructed with toxin-like protein sequences obtained from the analysis of cDNA library from A. ventricosus venom glands. Our results indicate that a total of 130 toxin-like protein sequences were unambiguously identified by manual de novo sequencing coupled to LVPD search, accounting for 86.67% of all toxin-like proteins in LVPD. Thus manual de novo sequencing coupled to LVPD search was proved an extremely effective approach for the analysis of venom proteins. In addition, the approach displays impeccable advantage in validating mutant positions of isoforms from the same toxin-like family. Intriguingly, methyl esterifcation of glutamic acid was discovered for the first time in animal venom proteins by manual de novo sequencing.

  3. Construction of subtracted cDNA library of diferentially expressed genes of multidrug resistant tubercle bacillus by suppression subtracted hybridization%应用抑制消减杂交技术构建耐多药结核杆菌差异表达基因消减cDNA文库

    Institute of Scientific and Technical Information of China (English)

    张运玲; 郑改焕; 刘芮汐; 彭哲; 李奇志; 幸琳琳; 朱朝敏

    2012-01-01

    Objective: To build the subtracted cDNA library of differentially expressed genes of multidrug-resistant tubercle bacillus (MDR-TB)and to further discuss the molecular mechanism of MDR-TB. Methods:Tester was MDR-TB and Driver was sensitive tuberculosis. Suppression subtractive hybridization (SSH) and T/A cloning technology were done to build the subtracted cDNA library of differentially expressed genes of MDR-TB. Results:The subtracted cDNA library of differentially expressed genes of MDR-TB was successfully built and 113 differentially expressed cDNA fragements of MDR-TB were obtained. Sequencing and homology analysis showed that 5 of them were novel cDNA sequences and 5 sequenced genes were reported to be related with MDR in TB. Conclusions: SSH is an effective method for screening new function genes. Many genes both known and unknown are in correlation with MDR in TB. Discovery of these genes provides a solid foundation for the explanation of MDR mechanism in TB.%目的:构建结核杆菌耐多药株与敏感株的差异表达消减cDNA文库,进一步探索结核杆菌耐多药的分子机制.方法:以耐多药菌株cDNA为实验组(Tester),敏感株cDNA为驱动组(Driver)应用抑制消减杂交(Suppression subtractive hybridization,SSH)技术结合T/A克隆技术构建结核杆菌耐多药株与敏感株的差异表达消减cDNA文库.结果:成功构建了耐多药结核菌株差异表达消减cDNA文库,获得113个差异表达cDNA片段.结论:研究表明SSH技术是筛选新功能基因的有效方法;多种已知或未知基因均参与了结核杆菌耐多药的调节,大规模筛选与克隆这些基因为进一步研究结核杆菌耐多药机制的产生奠定了必要的理论基础.

  4. Cloning and analysis of a cDNA encoding acetohydroxy acid isomeroreductase from G2 pea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using cDNA representational difference analysis (cDNA RDA) method, we have successfully isolated a gene fragment whose expression was specifically induced by external GA3 application. Screening a G2 pea cDNA library using this fragment as a probe, we obtained a 2036 bp full-length cDNA. It contains a 1746 bp open reading frame and encodes a protein of 581 amino acids with a theoretical molecular weight of 64 ku. It shares high-level sequence identity with AAIR genes from other plant species. This cDNA was cloned into expression vector and recombinant E. coli DH5α cells with remarkable AAIR enzyme activity were obtained.

  5. An electrode probe for high-throughput screening of electrochemical libraries

    Science.gov (United States)

    Jiang, Rongzhong; Chu, Deryn

    2005-06-01

    A pen-shaped O2 electrode probe is designed for high-throughput screening of electrochemical libraries. The electrode probe consists of a large-area O2 electrode and a cylindrical electrolyte sponge with a short cone tip for screening. This type of design can easily minimize the probe resistance contributed by the electrolyte. A zinc electrode library is generated using a nonautomated method to deposit metal zinc on a graphite plate. The zinc electrode library and the O2-electrode probe form an electrochemical library containing 128 micro zinc/air batteries. High-throughput screening of the zinc/air batteries are carried out by moving the tip of the electrode probe under constant potential (1.0V) and measuring the current. A Gaussian distribution is used for statistical analysis of the experimental data. These data obtained with the combinatorial method have a relative standard deviation of 8.9% based on a nonautomated coating procedure. The O2 electrode probe is used to study the effect of addition of Cu in the anode on the performance of the zinc/air battery.

  6. Designing specific protein-protein interactions using computation, experimental library screening, or integrated methods.

    Science.gov (United States)

    Chen, T Scott; Keating, Amy E

    2012-07-01

    Given the importance of protein-protein interactions for nearly all biological processes, the design of protein affinity reagents for use in research, diagnosis or therapy is an important endeavor. Engineered proteins would ideally have high specificities for their intended targets, but achieving interaction specificity by design can be challenging. There are two major approaches to protein design or redesign. Most commonly, proteins and peptides are engineered using experimental library screening and/or in vitro evolution. An alternative approach involves using protein structure and computational modeling to rationally choose sequences predicted to have desirable properties. Computational design has successfully produced novel proteins with enhanced stability, desired interactions and enzymatic function. Here we review the strengths and limitations of experimental library screening and computational structure-based design, giving examples where these methods have been applied to designing protein interaction specificity. We highlight recent studies that demonstrate strategies for combining computational modeling with library screening. The computational methods provide focused libraries predicted to be enriched in sequences with the properties of interest. Such integrated approaches represent a promising way to increase the efficiency of protein design and to engineer complex functionality such as interaction specificity.

  7. Construction of the BAC Library of Small Abalone (Haliotis diversicolor) for Gene Screening and Genome Characterization.

    Science.gov (United States)

    Jiang, Likun; You, Weiwei; Zhang, Xiaojun; Xu, Jian; Jiang, Yanliang; Wang, Kai; Zhao, Zixia; Chen, Baohua; Zhao, Yunfeng; Mahboob, Shahid; Al-Ghanim, Khalid A; Ke, Caihuan; Xu, Peng

    2016-02-01

    The small abalone (Haliotis diversicolor) is one of the most important aquaculture species in East Asia. To facilitate gene cloning and characterization, genome analysis, and genetic breeding of it, we constructed a large-insert bacterial artificial chromosome (BAC) library, which is an important genetic tool for advanced genetics and genomics research. The small abalone BAC library includes 92,610 clones with an average insert size of 120 Kb, equivalent to approximately 7.6× of the small abalone genome. We set up three-dimensional pools and super pools of 18,432 BAC clones for target gene screening using PCR method. To assess the approach, we screened 12 target genes in these 18,432 BAC clones and identified 16 positive BAC clones. Eight positive BAC clones were then sequenced and assembled with the next generation sequencing platform. The assembled contigs representing these 8 BAC clones spanned 928 Kb of the small abalone genome, providing the first batch of genome sequences for genome evaluation and characterization. The average GC content of small abalone genome was estimated as 40.33%. A total of 21 protein-coding genes, including 7 target genes, were annotated into the 8 BACs, which proved the feasibility of PCR screening approach with three-dimensional pools in small abalone BAC library. One hundred fifty microsatellite loci were also identified from the sequences for marker development in the future. The BAC library and clone pools provided valuable resources and tools for genetic breeding and conservation of H. diversicolor.

  8. Screening for PreS specific binding ligands with a phage displayed peptides library

    Institute of Scientific and Technical Information of China (English)

    Qiang Deng; Ming Zhuang; Yu-Ying Kong; You-Hua Xie; Yuan Wang

    2005-01-01

    AIM: To construct a random peptide phage display library and search for peptides that specifically bind to the PreS region of hepatitis B virus (HBV).METHODS: A phage display vector, pFuse8, based on the gene 8 product (pⅧ) of M13 phage was made and used to construct a random peptide library. E. coli derived thioredoxin-PreS was purified with Thio-bond beads, and exploited as the bait protein for library screening. Five rounds of bio-panning were performed. The PreS-binding specificities of enriched phages were characterized with phage ELISA assay.RESULTS: A phage display vector was successfully constructed as demonstrated to present a pⅧ fused HBV PreS1 epitope on the phage surface with a high efficiency.A cysteine confined random peptide library was constructed containing independent clones exceeding 5±108 clone forming unit (CFU). A pool of phages showing a PreS-binding specificity was obtained after the screening against thioPres with an enrichment of approximately 400 times. Five phages with high PreS-binding specificities were selected and characterized. Sequences of the peptides displayed on these phages were determined.CONCLUSION: A phage library has been constructed,with random peptides displaying as pⅧ-fusion proteins.Specific PreS-binding peptides have been obtained, which may be useful for developing antivirals against HBV infection.

  9. Simulated Screens of DNA Encoded Libraries: The Potential Influence of Chemical Synthesis Fidelity on Interpretation of Structure-Activity Relationships.

    Science.gov (United States)

    Satz, Alexander L

    2016-07-11

    Simulated screening of DNA encoded libraries indicates that the presence of truncated byproducts complicates the relationship between library member enrichment and equilibrium association constant (these truncates result from incomplete chemical reactions during library synthesis). Further, simulations indicate that some patterns observed in reported experimental data may result from the presence of truncated byproducts in the library mixture and not structure-activity relationships. Potential experimental methods of minimizing the presence of truncates are assessed via simulation; the relationship between enrichment and equilibrium association constant for libraries of differing purities is investigated. Data aggregation techniques are demonstrated that allow for more accurate analysis of screening results, in particular when the screened library contains significant quantities of truncates.

  10. Use of cryopreserved cell aliquots in the high-throughput screening of small interfering RNA libraries.

    Science.gov (United States)

    Swearingen, Elissa A; Fajardo, Flordeliza; Wang, Xiangyun; Watson, J E Vivienne; Quon, Kim C; Kassner, Paul D

    2010-06-01

    Screening small interfering RNA (siRNA) libraries holds the potential to elucidate gene function as well as discover new targets for the therapeutic treatment of disease. Since the inception of siRNA as a discovery tool, there have been progressive improvements in siRNA design algorithms, the transfection reagents used to deliver them, and the assay formats used to monitor phenotypic changes. These changes have helped to improve the quality of the data emerging from siRNA screens. One variable that introduces inconsistency into high-throughput screening (HTS) of siRNA libraries is the state of the cells used in the assays. Multiple factors can contribute to differences in transfection efficiency as well as the basic cell biology, which can lead to differences in the genes identified in siRNA screens. The authors have developed a system using frozen cell aliquots to use in siRNA HTS, so that a major source of variability introduced into cell-based screens can be standardized. In addition, by transiently transfecting plasmids into cell lines and then freezing these cells down to use in siRNA transfection experiments, they have used this same technology to create new cell lines. This process of using aliquots of frozen cells is logistically advantageous in an HTS setting, as it reduces the time spent maintaining cell lines, as well as reducing possible downtime in screening due to lack of cells or poor cell health.

  11. CSBB-ConeExclusion, adapting structure based solution virtual screening to libraries on solid support.

    Science.gov (United States)

    Shave, Steven; Auer, Manfred

    2013-12-23

    Combinatorial chemical libraries produced on solid support offer fast and cost-effective access to a large number of unique compounds. If such libraries are screened directly on-bead, the speed at which chemical space can be explored by chemists is much greater than that addressable using solution based synthesis and screening methods. Solution based screening has a large supporting body of software such as structure-based virtual screening tools which enable the prediction of protein-ligand complexes. Use of these techniques to predict the protein bound complexes of compounds synthesized on solid support neglects to take into account the conjugation site on the small molecule ligand. This may invalidate predicted binding modes, the linker may be clashing with protein atoms. We present CSBB-ConeExclusion, a methodology and computer program which provides a measure of the applicability of solution dockings to solid support. Output is given in the form of statistics for each docking pose, a unique 2D visualization method which can be used to determine applicability at a glance, and automatically generated PyMol scripts allowing visualization of protein atom incursion into a defined exclusion volume. CSBB-ConeExclusion is then exemplarically used to determine the optimum attachment point for a purine library targeting cyclin-dependent kinase 2 CDK2.

  12. Screening Carbohydrate Libraries for Protein Interactions Using the Direct ESI-MS Assay. Applications to Libraries of Unknown Concentration

    Science.gov (United States)

    Kitova, Elena N.; El-Hawiet, Amr; Klassen, John S.

    2014-08-01

    A semiquantitative electrospray ionization mass spectrometry (ESI-MS) binding assay suitable for analyzing mixtures of oligosaccharides, at unknown concentrations, for interactions with target proteins is described. The assay relies on the differences in the ratio of the relative abundances of the ligand-bound and free protein ions measured by ESI-MS at two or more initial protein concentrations to distinguish low affinity (≤103 M-1) ligands from moderate and high affinity (>105 M-1) ligands present in the library and to rank their affinities. Control experiments were performed on solutions of a single chain antibody and a mixture of synthetic oligosaccharides, with known affinities, in the absence and presence of a 40-component carbohydrate library to demonstrate the implementation and reliability of the assay. The application of the assay for screening natural libraries of carbohydrates against proteins is also demonstrated using mixtures of human milk oligosaccharides, isolated from breast milk, and fragments of a bacterial toxin and human galectin 3.

  13. 青枯菌诱导的烟草叶片全长cDNA文库的构建和初步分析%Construction and Primary Analysis of Tobacco Leaf Full-length cDNA Library Induced by Ralstonia Solanacearumr

    Institute of Scientific and Technical Information of China (English)

    张冲; 蔡铁城; 陈华; 曾建斌; 庄伟建

    2013-01-01

    Leaves of high quality flue-cured tobacco variety K326 were inoculated by Ralstonia Solanacearum and harvested at different time point. Total RNA was extracted by CTAB method. Library construction was carried out by Creator SMART cDNA Library Construction Kit (CLONTECH Laboratories) in accordance with the manu- facturer's protocol. Briefly, total RNA was used as starting material to synthesize first-strand cDNA. Then, Double-Stranded cDNA was synthesised by Low-Cycle PCR on a DNA Thermal Cycler. Following double- stranded cDNA synthesis, which was incubated with proteinase K to degrade the thermostable DNA polymerases. After digestion, the cDNA was purified from a low-melt agarose gel to remove small fragments (<750 bp) and was directionally cloned into SfiI A&B-digested vector pDNR-LIB as described. A full-length cDNA library was constructed with the primary library titer of 1.902 ×106 cfu/mL and 2.97 ×109 cfu/mL for the amplyfied titer. Inserts ranged from 0.75~2.0 kb and average insert size of the clones was larger than 1 300 bp, and also with a high recombination rate of 99%. Fivety clones were randomly picked from the libraries for sequencing and functional analysis. The results indicated that the library was of high quality, which serve as invaluable genetic resource for further cloning and screening special genes involved in Ralstonia Solanacearum resistance and tobacco genetic improvement.%以优质高抗青枯病烤烟品种K326为材料,在苗期利用注射法接种烟草青枯菌,分不同时期取叶片,利用CTAB法提取接种和非接种的混合RNA,采用SMART (switching mechanism at 5' end of RNA tra-nscript)技术合成双链cDNA,经SfiⅠ酶切后胶回收纯化双链cDNA,连接到质粒载体pDNR-LIB上,电击转化大肠杆菌DH5α感受态细胞,成功构建了青枯菌诱导的烟草叶片全长cDNA文库。经鉴定,初级文库库容为1.902×106 cfu/mL,重组率达到98%以上,插入片段集中在0.75~2.0 kb

  14. Cloning and expression analysis of MBLL cDNA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The mbl (muscleblind) gene of Drosophila encodes a nuclear protein which contains two Cys3His motifs. The mutation of mbl gene will disturb the differentiation of all the Drosophila's photoreceptors. Primers have been designed according to human EST086139, which is highly homologous to mbl gene. Human fetal brain cDNA library has been screened and a novel cDNA clone has been obtained. The 2595 bp cDNA, designated MBLL (muscleblind-like), contains an open reading frame which encodes 255 amino acids and has 4 Cys3His motifs (GenBank Acc. AF061261). The amino acids sequence shares high homology to Drosophila's mbl. The Northern blot and RNA dot blot hybridization of 43 human adult tissues and 7 fetal tissues show that MBLL is a widely expressed gene, but the expression amounts differ in these tissues.

  15. Screening target specificity of siRNAs by rapid amplification of cDNA ends (RACE) for non-sequenced species.

    Science.gov (United States)

    Sabirzhanov, Boris; Sabirzhanova, Inna B; Keifer, Joyce

    2011-05-01

    RNA interference (RNAi) is the process of sequence-specific posttranslational gene silencing triggered by double-stranded RNAs (dsRNAs). RNAi is a widely used approach for studying gene function. However, studies have shown that using siRNA can lead to off-target effects when the siRNA contains sufficient sequence identity to non-target mRNA sequences. One of the important steps in designing dsRNA is verification that it has sequence identity to only the target mRNA. In this report, we propose an approach for primary screening dsRNAs for potential off-target effects by using rapid amplification of cDNA ends. This method can be especially useful for model systems using species that have limited availability of sequence data.

  16. High-throughput drug library screening identifies colchicine as a thyroid cancer inhibitor.

    Science.gov (United States)

    Zhang, Le; Yang, Zhaoying; Granieri, Letizia; Pasculescu, Adrian; Datti, Alessandro; Asa, Sylvia L; Xu, Zheli; Ezzat, Shereen

    2016-04-12

    We employed a high-throughput drug library screening platform to identify novel agents affecting thyroid cancer cells. We used human thyroid cancer cell lines to screen a collection of approximately 5200 small molecules with biological and/or pharmacologial properties. Parallel primary screens yielded a number of hits differentially active between thyroid and melanoma cells. Amongst compounds specifically targeting thyroid cancer cells, colchicine emerged as an effective candidate. Colchicine inhibited cell growth which correlated with G2 cell cycle arrest and apoptosis. These effects were hampered through inhibition of MEK1/2 and JNK. In contrast, inhibition of p38-MAPK had little effect, and AKT had no impact on colchicine action. Systemic colchicine inhibited thyroid cancer progression in xenografted mice. These findings demonstrate that our screening platform is an effective vehicle for drug reposition and show that colchicine warrants further attention in well-defined clinical niches such as thyroid cancer.

  17. High-throughput drug library screening identifies colchicine as a thyroid cancer inhibitor

    Science.gov (United States)

    Zhang, Le; Yang, Zhaoying; Granieri, Letizia; Pasculescu, Adrian; Datti, Alessandro; Asa, Sylvia L.; Xu, Zheli; Ezzat, Shereen

    2016-01-01

    We employed a high-throughput drug library screening platform to identify novel agents affecting thyroid cancer cells. We used human thyroid cancer cell lines to screen a collection of approximately 5200 small molecules with biological and/or pharmacologial properties. Parallel primary screens yielded a number of hits differentially active between thyroid and melanoma cells. Amongst compounds specifically targeting thyroid cancer cells, colchicine emerged as an effective candidate. Colchicine inhibited cell growth which correlated with G2 cell cycle arrest and apoptosis. These effects were hampered through inhibition of MEK1/2 and JNK. In contrast, inhibition of p38-MAPK had little effect, and AKT had no impact on colchicine action. Systemic colchicine inhibited thyroid cancer progression in xenografted mice. These findings demonstrate that our screening platform is an effective vehicle for drug reposition and show that colchicine warrants further attention in well-defined clinical niches such as thyroid cancer. PMID:26942566

  18. Increasing the delivery of next generation therapeutics from high throughput screening libraries.

    Science.gov (United States)

    Wigglesworth, Mark J; Murray, David C; Blackett, Carolyn J; Kossenjans, Michael; Nissink, J Willem M

    2015-06-01

    The pharmaceutical industry has historically relied on high throughput screening as a cornerstone to identify chemical equity for drug discovery projects. However, with pharmaceutical companies moving through a phase of diminished returns and alternative hit identification strategies proving successful, it is more important than ever to understand how this approach can be used more effectively to increase the delivery of next generation therapeutics from high throughput screening libraries. There is a wide literature that describes HTS and fragment based screening approaches which offer clear direction on the process for these two distinct activities. However, few people have considered how best to identify medium to low molecular weight compounds from large diversity screening sets and increase downstream success.

  19. Isolation, Identification and cDNA Library Construction of Glyphosate-Resistant Fungus ( Candida palmioleophila )%抗草甘膦真菌(Candida palmioleophila)分离鉴定及其cDNA文库构建

    Institute of Scientific and Technical Information of China (English)

    于海涛; 金龙国; 蒋凌雪; 韩玉军; 陶波; 邱丽娟

    2012-01-01

    A glyphosate-resistant fungus strain was isolated from sludge of glyphosate factory outfall by the flask-foster enrichment technology. Based on its morphological, physiological and biochemical properties as well as the 18S rRNA sequence analysis results,the strain was tentatively identified as Candida palmioleophila. A cDNA library driven by the total RNA extracted from the strain was constructed by SMARTer technology of Clontech company. The library quality was evaluated, and the results showed that the titer of primary cDNA library and amplified cDNA library were 2. 58 x 106 cfu/mL and 3. 42 x 109 cfu/mL, respectively, with the library volume of about 2. 58 x 106 cfu and the recombination rate of 97. 6%. The inserted fragments were distributed from 500bp to 3kb,and the most cDNA fragments were distributed around lkb. These results indicated that the strain TY-JM cDNA library was constructed successfully.%利用瓶培养富集技术从生产草甘膦工厂排污口的污泥中筛选抗草甘膦菌株,通过菌株形态学鉴定、生理生化特性测定及18S rRNA序列分析,确定其为假丝酵母菌(Candida palmioleophila).以供试的抗草甘膦菌株总RNA为起始模板,利用Clontech公司的SMARTer技术构建cDNA文库.文库质量鉴定表明:原始文库滴度为2.58×106cfu/mL,扩增后文库滴度为3.42×109cfu/mL,文库库容为2.58×106cfu,重组率为97.6%,插入片段范围为500bp ~3kb,主要集中在1kb附近.表明构建的TY-JM的cDNA文库质量符合要求.

  20. Cloning Full-Length cDNAs from Vascular Tissues and Cells by Rapid Amplification of cDNA Ends (RACE) and RT-PCR.

    Science.gov (United States)

    Shen

    1999-01-01

    The isolation of full-length cDNAs remains a frequent task undertaken in many laboratories. A full-length cDNA is often desirable for one of the following purposes: 1) to complete the sequence of a partial cDNA cloned by library screenings or the yeast one- or two-hybrid system; 2) to derive the cDNA sequence encoding a protein, based on peptide sequences; 3) to obtain the sequence of a reported cDNA for functional analysis or expression studies; and 4) to define exon/intron boundaries of a cloned gene or determine transcription start site(s) of a promoter.

  1. Construction and analysis of subtractive cDNA library of recovery body wall in sea cucumber Apostichopus japonicus%仿刺参体壁创伤修复消减文库的构建与分析

    Institute of Scientific and Technical Information of China (English)

    秦艳杰; 李霞; 张慧敏; 王雪

    2013-01-01

    应用抑制性消减杂交技术(SSH),构建了仿刺参Apostichopus japonicus(体质量为65 ~90 g)正常体壁及创伤修复(24、48、72、96、120 h后)体壁的消减cDNA文库,利用PCR和斑点杂交技术对文库进行筛选,随机挑取的768个克隆中发现292个阳性克隆,对其中信号强度较强的224个阳性克隆进行测序,得到208个有效EST序列.经BlastX工具对获得的EST与GenBank数据库进行比对分析,结果有171个EST序列与数据库中的基因同源(e≤0.001,相似性>40%),其中153个为未知基因,18个为已知功能或已命名基因,包括在创伤及修复的体壁中上调表达的β微管蛋白、微管蛋白α-1链、肌动蛋白、肌动蛋白ike 7B类似物、细胞色素c氧化酶亚基Ⅰ、tRNA假尿苷合成酶A、GTP酶、细胞分裂周期2类似蛋白、有丝分裂原活化蛋白激酶、homeobox蛋白、延伸因子1A、核糖体蛋白L30、核糖体蛋白L17、60S酸性核糖体蛋白PO、26S蛋白酶调节亚基、泛素特异性肽酶24、大肠癌血清抗原3、清道夫受体蛋白12等.本研究结果可为探讨刺参体壁再生过程和分子机理,以及筛选刺参体壁创伤修复过程中相关功能基因的研究提供基础依据.%A subtracted cDNA library of sea cucumber Apostichopus japonicus(body weight 65-90 g) was constructed by suppression subtractive hybridization technology (SSH) to screen EST associated with recovery body wall.The cDNA library of the test group has been constructed by the mRNA of the body walls 24,48,72,96 and 120h after the operation,and those with no operation as the control group.Differential EST from the subtracted cDNA library have been identified by both PCR technology and dot blot hybridization.Two hundred and ninety-two positive clones were observed from total 768 clones,and 224 positive ones were sequenced.Two hundred and eight EST were found and analyzed by BlastX tool in GenBank database,in which 171 EST were homologous with sequences

  2. Identification of Small Molecule Modulators of MicroRNA by Library Screening.

    Science.gov (United States)

    Xiao, Zhangang; Chen, Yangchao

    2017-01-01

    MicroRNAs (miRNAs) function as oncogenes or tumor suppressors and are dysregulated in cancer. miRNAs therefore represent promising therapeutic targets for cancer. Small molecules that could modulate the expression of miRNAs would thus have potential as anticancer agents. Library screening of small molecules targeting miRNAs is a useful technology platform for anticancer drug development. Here, we describe a hepatocellular carcinoma (HCC) cell-based luciferase reporter system which could be used to screen for small molecule modulators of tumor suppressor microRNA-34a.

  3. Small-molecule library screening by docking with PyRx.

    Science.gov (United States)

    Dallakyan, Sargis; Olson, Arthur J

    2015-01-01

    Virtual molecular screening is used to dock small-molecule libraries to a macromolecule in order to find lead compounds with desired biological function. This in silico method is well known for its application in computer-aided drug design. This chapter describes how to perform small-molecule virtual screening by docking with PyRx, which is open-source software with an intuitive user interface that runs on all major operating systems (Linux, Windows, and Mac OS). Specific steps for using PyRx, as well as considerations for data preparation, docking, and data analysis, are also described.

  4. Human genomic library screened with 17-base oligonucleotide probes yields a novel interferon gene.

    OpenAIRE

    Torczynski, R M; Fuke, M; Bollon, A P

    1984-01-01

    A method is presented that has permitted a human genomic library to be screened for low-copy genes using 17-base synthetic oligonucleotides as probes. Parallel screening with two different 17-base probes permitted the unambiguous identification of clones containing interferon-alpha (IFN-alpha) genes. The isolated human IFN-alpha genes were sequenced, and one appears to be IFN-alpha L; the other is one not previously described, which we have designated IFN-alpha WA. The IFN-alpha WA sequence d...

  5. Functional screening of metagenome and genome libraries for detection of novel flavonoid-modifying enzymes.

    Science.gov (United States)

    Rabausch, U; Juergensen, J; Ilmberger, N; Böhnke, S; Fischer, S; Schubach, B; Schulte, M; Streit, W R

    2013-08-01

    The functional detection of novel enzymes other than hydrolases from metagenomes is limited since only a very few reliable screening procedures are available that allow the rapid screening of large clone libraries. For the discovery of flavonoid-modifying enzymes in genome and metagenome clone libraries, we have developed a new screening system based on high-performance thin-layer chromatography (HPTLC). This metagenome extract thin-layer chromatography analysis (META) allows the rapid detection of glycosyltransferase (GT) and also other flavonoid-modifying activities. The developed screening method is highly sensitive, and an amount of 4 ng of modified flavonoid molecules can be detected. This novel technology was validated against a control library of 1,920 fosmid clones generated from a single Bacillus cereus isolate and then used to analyze more than 38,000 clones derived from two different metagenomic preparations. Thereby we identified two novel UDP glycosyltransferase (UGT) genes. The metagenome-derived gtfC gene encoded a 52-kDa protein, and the deduced amino acid sequence was weakly similar to sequences of putative UGTs from Fibrisoma and Dyadobacter. GtfC mediated the transfer of different hexose moieties and exhibited high activities on flavones, flavonols, flavanones, and stilbenes and also accepted isoflavones and chalcones. From the control library we identified a novel macroside glycosyltransferase (MGT) with a calculated molecular mass of 46 kDa. The deduced amino acid sequence was highly similar to sequences of MGTs from Bacillus thuringiensis. Recombinant MgtB transferred the sugar residue from UDP-glucose effectively to flavones, flavonols, isoflavones, and flavanones. Moreover, MgtB exhibited high activity on larger flavonoid molecules such as tiliroside.

  6. Synthetic molecular evolution of pore-forming peptides by iterative combinatorial library screening.

    Science.gov (United States)

    Krauson, Aram J; He, Jing; Wimley, Andrew W; Hoffmann, Andrew R; Wimley, William C

    2013-04-19

    We previously reported the de novo design of a combinatorial peptide library that was subjected to high-throughput screening to identify membrane-permeabilizing antimicrobial peptides that have β-sheet-like secondary structure. Those peptides do not form discrete pores in membranes but instead partition into membrane interfaces and cause transient permeabilization by membrane disruption, but only when present at high concentration. In this work, we used a consensus sequence from that initial screen as a template to design an iterative, second generation library. In the 24-26-residue, 16,200-member second generation library we varied six residues. Two diad repeat motifs of alternating polar and nonpolar amino acids were preserved to maintain a propensity for non-helical secondary structure. We used a new high-throughput assay to identify members that self-assemble into equilibrium pores in synthetic lipid bilayers. This screen was done at a very stringent peptide to lipid ratio of 1:1000 where most known membrane-permeabilizing peptides, including the template peptide, are not active. In a screen of 10,000 library members we identified 16 (~0.2%) that are equilibrium pore-formers at this high stringency. These rare and highly active peptides, which share a common sequence motif, are as potent as the most active pore-forming peptides known. Furthermore, they are not α-helical, which makes them unusual, as most of the highly potent pore-forming peptides are amphipathic α-helices. Here we demonstrate that this synthetic molecular evolution-based approach, taken together with the new high-throughput tools we have developed, enables the identification, refinement, and optimization of unique membrane active peptides.

  7. Generation of polymerase chain reaction-specific probes for library screening using single degenerate primers.

    Science.gov (United States)

    Hommes, N G; Arp, D J; Sayavedra-Soto, L A

    1995-03-01

    Degenerate oligonucleotide primers were made to peptide sequences from hydroxylamine oxidoreductase (HAO) from Nitrosomonas europaea. The primers were used singly in PCR reactions to amplify portions of the gene for HAO from genomic DNA. Southern hybridizations using fragments amplified with each primer showed that they labeled the same genomic DNA fragments. The PCR-amplified fragments were successfully used to screen a gene library for clones containing the HAO gene. The method of isolating genes by PCR with single primers has general utility.

  8. Engineering of Immunoglobulin Fc Heterodimers Using Yeast Surface-Displayed Combinatorial Fc Library Screening.

    Directory of Open Access Journals (Sweden)

    Hye-Ji Choi

    Full Text Available Immunoglobulin Fc heterodimers, which are useful scaffolds for the generation of bispecific antibodies, have been mostly generated through structure-based rational design methods that introduce asymmetric mutations into the CH3 homodimeric interface to favor heterodimeric Fc formation. Here, we report an approach to generate heterodimeric Fc variants through directed evolution combined with yeast surface display. We developed a combinatorial heterodimeric Fc library display system by mating two haploid yeast cell lines, one haploid cell line displayed an Fc chain library (displayed FcCH3A with mutations in one CH3 domain (CH3A on the yeast cell surface, and the other cell line secreted an Fc chain library (secreted FcCH3B with mutations in the other CH3 domain (CH3B. In the mated cells, secreted FcCH3B is displayed on the cell surface through heterodimerization with the displayed FcCH3A, the detection of which enabled us to screen the library for heterodimeric Fc variants. We constructed combinatorial heterodimeric Fc libraries with simultaneous mutations in the homodimer-favoring electrostatic interaction pairs K370-E357/S364 or D399-K392/K409 at the CH3 domain interface. High-throughput screening of the libraries using flow cytometry yielded heterodimeric Fc variants with heterodimer-favoring CH3 domain interface mutation pairs, some of them showed high heterodimerization yields (~80-90% with previously unidentified CH3 domain interface mutation pairs, such as hydrogen bonds and cation-π interactions. Our study provides a new approach for engineering Fc heterodimers that could be used to engineer other heterodimeric protein-protein interactions through directed evolution combined with yeast surface display.

  9. Engineering of Immunoglobulin Fc Heterodimers Using Yeast Surface-Displayed Combinatorial Fc Library Screening.

    Science.gov (United States)

    Choi, Hye-Ji; Kim, Ye-Jin; Choi, Dong-Ki; Kim, Yong-Sung

    2015-01-01

    Immunoglobulin Fc heterodimers, which are useful scaffolds for the generation of bispecific antibodies, have been mostly generated through structure-based rational design methods that introduce asymmetric mutations into the CH3 homodimeric interface to favor heterodimeric Fc formation. Here, we report an approach to generate heterodimeric Fc variants through directed evolution combined with yeast surface display. We developed a combinatorial heterodimeric Fc library display system by mating two haploid yeast cell lines, one haploid cell line displayed an Fc chain library (displayed FcCH3A) with mutations in one CH3 domain (CH3A) on the yeast cell surface, and the other cell line secreted an Fc chain library (secreted FcCH3B) with mutations in the other CH3 domain (CH3B). In the mated cells, secreted FcCH3B is displayed on the cell surface through heterodimerization with the displayed FcCH3A, the detection of which enabled us to screen the library for heterodimeric Fc variants. We constructed combinatorial heterodimeric Fc libraries with simultaneous mutations in the homodimer-favoring electrostatic interaction pairs K370-E357/S364 or D399-K392/K409 at the CH3 domain interface. High-throughput screening of the libraries using flow cytometry yielded heterodimeric Fc variants with heterodimer-favoring CH3 domain interface mutation pairs, some of them showed high heterodimerization yields (~80-90%) with previously unidentified CH3 domain interface mutation pairs, such as hydrogen bonds and cation-π interactions. Our study provides a new approach for engineering Fc heterodimers that could be used to engineer other heterodimeric protein-protein interactions through directed evolution combined with yeast surface display.

  10. Determination of the sequence specificity of XIAP BIR domains by screening a combinatorial peptide library.

    Science.gov (United States)

    Sweeney, Michael C; Wang, Xianxi; Park, Junguk; Liu, Yusen; Pei, Dehua

    2006-12-12

    Inhibitor of apoptosis (IAP) proteins regulate programmed cell death by inhibiting members of the caspase family of proteases. The X-chromosome-linked IAP (XIAP) contains three baculovirus IAP repeat (BIR) domains, which bind directly to the N-termini of target proteins including those of caspases-3, -7, and -9. In the present study, we defined the consensus sequences of the motifs that interact with the three BIR domains in an unbiased manner. A combinatorial peptide library containing four random residues at the N-terminus was constructed and screened using BIR domains as probes. We found that the BIR3 domain binds a highly specific motif containing an alanine or valine at the N-terminus (P1 position), an arginine or proline at the P3 position, and a hydrophobic residue (Phe, Ile, and Tyr) at the P4 position. The BIR2-binding motif is less stringent. Although it still requires an N-terminal alanine, it tolerates a wide variety of amino acids at P2-P4 positions. The BIR1 failed to bind to any peptides in the library. SPR analysis of individually synthesized peptides confirmed the library screening results. Database searches with the BIR2- and BIR3-binding consensus sequences revealed a large number of potential target proteins. The combinatorial library method should be readily applicable to other BIR domains or other types of protein modular domains.

  11. Yeast two-hybrid screen.

    Science.gov (United States)

    Makuch, Lauren

    2014-01-01

    Yeast two-hybrid is a method for screening large numbers of gene products (encoded by cDNA libraries) for their ability to interact with a protein of interest. This system can also be used for characterizing and manipulating candidate protein: protein interactions. Interactions between proteins are monitored by the growth of yeast plated on selective media.

  12. An Integrated Microfluidic Processor for DNA-Encoded Combinatorial Library Functional Screening

    Science.gov (United States)

    2017-01-01

    DNA-encoded synthesis is rekindling interest in combinatorial compound libraries for drug discovery and in technology for automated and quantitative library screening. Here, we disclose a microfluidic circuit that enables functional screens of DNA-encoded compound beads. The device carries out library bead distribution into picoliter-scale assay reagent droplets, photochemical cleavage of compound from the bead, assay incubation, laser-induced fluorescence-based assay detection, and fluorescence-activated droplet sorting to isolate hits. DNA-encoded compound beads (10-μm diameter) displaying a photocleavable positive control inhibitor pepstatin A were mixed (1920 beads, 729 encoding sequences) with negative control beads (58 000 beads, 1728 encoding sequences) and screened for cathepsin D inhibition using a biochemical enzyme activity assay. The circuit sorted 1518 hit droplets for collection following 18 min incubation over a 240 min analysis. Visual inspection of a subset of droplets (1188 droplets) yielded a 24% false discovery rate (1166 pepstatin A beads; 366 negative control beads). Using template barcoding strategies, it was possible to count hit collection beads (1863) using next-generation sequencing data. Bead-specific barcodes enabled replicate counting, and the false discovery rate was reduced to 2.6% by only considering hit-encoding sequences that were observed on >2 beads. This work represents a complete distributable small molecule discovery platform, from microfluidic miniaturized automation to ultrahigh-throughput hit deconvolution by sequencing. PMID:28199790

  13. A colony multiplex quantitative PCR-Based 3S3DBC method and variations of it for screening DNA libraries.

    Directory of Open Access Journals (Sweden)

    Yang An

    Full Text Available A DNA library is a collection of DNA fragments cloned into vectors and stored individually in host cells, and is a valuable resource for molecular cloning, gene physical mapping, and genome sequencing projects. To take the best advantage of a DNA library, a good screening method is needed. After describing pooling strategies and issues that should be considered in DNA library screening, here we report an efficient colony multiplex quantitative PCR-based 3-step, 3-dimension, and binary-code (3S3DBC method we used to screen genes from a planarian genomic DNA fosmid library. This method requires only 3 rounds of PCR reactions and only around 6 hours to distinguish one or more desired clones from a large DNA library. According to the particular situations in different research labs, this method can be further modified and simplified to suit their requirements.

  14. The mathematics of a successful deconvolution: a quantitative assessment of mixture-based combinatorial libraries screened against two formylpeptide receptors.

    Science.gov (United States)

    Santos, Radleigh G; Appel, Jon R; Giulianotti, Marc A; Edwards, Bruce S; Sklar, Larry A; Houghten, Richard A; Pinilla, Clemencia

    2013-05-30

    In the past 20 years, synthetic combinatorial methods have fundamentally advanced the ability to synthesize and screen large numbers of compounds for drug discovery and basic research. Mixture-based libraries and positional scanning deconvolution combine two approaches for the rapid identification of specific scaffolds and active ligands. Here we present a quantitative assessment of the screening of 32 positional scanning libraries in the identification of highly specific and selective ligands for two formylpeptide receptors. We also compare and contrast two mixture-based library approaches using a mathematical model to facilitate the selection of active scaffolds and libraries to be pursued for further evaluation. The flexibility demonstrated in the differently formatted mixture-based libraries allows for their screening in a wide range of assays.

  15. The Mathematics of a Successful Deconvolution: A Quantitative Assessment of Mixture-Based Combinatorial Libraries Screened Against Two Formylpeptide Receptors

    Directory of Open Access Journals (Sweden)

    Richard A. Houghten

    2013-05-01

    Full Text Available In the past 20 years, synthetic combinatorial methods have fundamentally advanced the ability to synthesize and screen large numbers of compounds for drug discovery and basic research. Mixture-based libraries and positional scanning deconvolution combine two approaches for the rapid identification of specific scaffolds and active ligands. Here we present a quantitative assessment of the screening of 32 positional scanning libraries in the identification of highly specific and selective ligands for two formylpeptide receptors. We also compare and contrast two mixture-based library approaches using a mathematical model to facilitate the selection of active scaffolds and libraries to be pursued for further evaluation. The flexibility demonstrated in the differently formatted mixture-based libraries allows for their screening in a wide range of assays.

  16. The Mathematics of a Successful Deconvolution: A Quantitative Assessment of Mixture-Based Combinatorial Libraries Screened Against Two Formylpeptide Receptors

    Science.gov (United States)

    Santos, Radleigh G.; Appel, Jon R.; Giulianotti, Marc A.; Edwards, Bruce S.; Sklar, Larry A.; Houghten, Richard A.; Pinilla, Clemencia

    2014-01-01

    In the past 20 years, synthetic combinatorial methods have fundamentally advanced the ability to synthesize and screen large numbers of compounds for drug discovery and basic research. Mixture-based libraries and positional scanning deconvolution combine two approaches for the rapid identification of specific scaffolds and active ligands. Here we present a quantitative assessment of the screening of 32 positional scanning libraries in the identification of highly specific and selective ligands for two formylpeptide receptors. We also compare and contrast two mixture-based library approaches using a mathematical model to facilitate the selection of active scaffolds and libraries to be pursued for further evaluation. The flexibility demonstrated in the differently formatted mixture-based libraries allows for their screening in a wide range of assays. PMID:23722730

  17. A high-throughput screen for aggregation-based inhibition in a large compound library.

    Science.gov (United States)

    Feng, Brian Y; Simeonov, Anton; Jadhav, Ajit; Babaoglu, Kerim; Inglese, James; Shoichet, Brian K; Austin, Christopher P

    2007-05-17

    High-throughput screening (HTS) is the primary technique for new lead identification in drug discovery and chemical biology. Unfortunately, it is susceptible to false-positive hits. One common mechanism for such false-positives is the congregation of organic molecules into colloidal aggregates, which nonspecifically inhibit enzymes. To both evaluate the feasibility of large-scale identification of aggregate-based inhibition and quantify its prevalence among screening hits, we tested 70,563 molecules from the National Institutes of Health Chemical Genomics Center (NCGC) library for detergent-sensitive inhibition. Each molecule was screened in at least seven concentrations, such that dose-response curves were obtained for all molecules in the library. There were 1274 inhibitors identified in total, of which 1204 were unambiguously detergent-sensitive. We identified these as aggregate-based inhibitors. Thirty-one library molecules were independently purchased and retested in secondary low-throughput experiments; 29 of these were confirmed as either aggregators or nonaggregators, as appropriate. Finally, with the dose-response information collected for every compound, we could examine the correlation between aggregate-based inhibition and steep dose-response curves. Three key results emerge from this study: first, detergent-dependent identification of aggregate-based inhibition is feasible on the large scale. Second, 95% of the actives obtained in this screen are aggregate-based inhibitors. Third, aggregate-based inhibition is correlated with steep dose-response curves, although not absolutely. The results of this screen are being released publicly via the PubChem database.

  18. MISSION LentiPlex pooled shRNA library screening in mammalian cells.

    Science.gov (United States)

    Coussens, Matthew J; Corman, Courtney; Fischer, Ashley L; Sago, Jack; Swarthout, John

    2011-12-21

    RNA interference (RNAi) is an intrinsic cellular mechanism for the regulation of gene expression. Harnessing the innate power of this system enables us to knockdown gene expression levels in loss of gene function studies. There are two main methods for performing RNAi. The first is the use of small interfering RNAs (siRNAs) that are chemically synthesized, and the second utilizes short-hairpin RNAs (shRNAs) encoded within plasmids. The latter can be transfected into cells directly or packaged into replication incompetent lentiviral particles. The main advantages of using lentiviral shRNAs is the ease of introduction into a wide variety of cell types, their ability to stably integrate into the genome for long term gene knockdown and selection, and their efficacy in conducting high-throughput loss of function screens. To facilitate this we have created the LentiPlex pooled shRNA library. The MISSION LentiPlex Human shRNA Pooled Library is a genome-wide lentiviral pool produced using a proprietary process. The library consists of over 75,000 shRNA constructs from the TRC collection targeting 15,000+ human genes. Each library is tested for shRNA representation before product release to ensure robust library coverage. The library is provided in a ready-to-use lentiviral format at titers of at least 5 x 10(8) TU/ml via p24 assay and is pre-divided into ten subpools of approximately 8,000 shRNA constructs each. Amplification and sequencing primers are also provided for downstream target identification. Previous studies established a synergistic antitumor activity of TRAIL when combined with Paclitaxel in A549 cells, a human lung carcinoma cell line. In this study we demonstrate the application of a pooled LentiPlex shRNA library to rapidly conduct a positive selection screen for genes involved in the cytotoxicity of A549 cells when exposed to TRAIL and Paclitaxel. One barrier often encountered with high-throughput screens is the cost and difficulty in deconvolution; we

  19. cDNA amplification by SMART-PCR and suppression subtractive hybridization (SSH)-PCR.

    Science.gov (United States)

    Hillmann, Andrew; Dunne, Eimear; Kenny, Dermot

    2009-01-01

    The comparison of two RNA populations that differ from the effects of a single-independent variable, such as a drug treatment or a specific genetic defect, can identify differences in the abundance of specific transcripts that vary in a population-dependent manner. There are a variety of methods for identifying differentially expressed genes, including microarray, SAGE, qRT-PCR, and DDGE. This protocol describes a potentially less sensitive yet relatively easy and cost-effective alternative that does not require prior knowledge of the transcriptomes under investigation and is particularly applicable when minimal levels of starting material, RNA, are available. RNA input can often be a limiting factor when analyzing RNA from, for example, rigorously purified blood cells. This protocol describes the use of SMART-PCR to amplify cDNA from sub-microgram levels of RNA. The amplified cDNA populations under comparison are then subjected to suppression subtractive hybridization (SSH-PCR), a technique that couples subtractive hybridization with suppression PCR to selectively amplify fragments of differentially expressed genes. The final products are cDNA populations enriched for significantly over-represented transcripts in either of the two input RNA preparations. These cDNA populations may then be cloned to make subtracted cDNA libraries and/or used as probes to screen subtracted cDNA, global cDNA, or genomic DNA libraries.

  20. Design of a multi-purpose fragment screening library using molecular complexity and orthogonal diversity metrics.

    Science.gov (United States)

    Lau, Wan F; Withka, Jane M; Hepworth, David; Magee, Thomas V; Du, Yuhua J; Bakken, Gregory A; Miller, Michael D; Hendsch, Zachary S; Thanabal, Venkataraman; Kolodziej, Steve A; Xing, Li; Hu, Qiyue; Narasimhan, Lakshmi S; Love, Robert; Charlton, Maura E; Hughes, Samantha; van Hoorn, Willem P; Mills, James E

    2011-07-01

    Fragment Based Drug Discovery (FBDD) continues to advance as an efficient and alternative screening paradigm for the identification and optimization of novel chemical matter. To enable FBDD across a wide range of pharmaceutical targets, a fragment screening library is required to be chemically diverse and synthetically expandable to enable critical decision making for chemical follow-up and assessing new target druggability. In this manuscript, the Pfizer fragment library design strategy which utilized multiple and orthogonal metrics to incorporate structure, pharmacophore and pharmacological space diversity is described. Appropriate measures of molecular complexity were also employed to maximize the probability of detection of fragment hits using a variety of biophysical and biochemical screening methods. In addition, structural integrity, purity, solubility, fragment and analog availability as well as cost were important considerations in the selection process. Preliminary analysis of primary screening results for 13 targets using NMR Saturation Transfer Difference (STD) indicates the identification of uM-mM hits and the uniqueness of hits at weak binding affinities for these targets.

  1. BiebBeep: An Interactive Screen for Supporting Public Library 2.0 Information and Social Services

    NARCIS (Netherlands)

    Kanis, Marije; Meys, Wouter; Groen, Maarten; Veenstra, Mettina; Slakhorst, Wout

    2011-01-01

    This video presents BiebBeep, an interactive touchscreen system that has been developed with the aim to support information and social services for the New Library in Almere, The Netherlands. The constantly updated information displayed on the interactive screen concerns not only the library itself,

  2. DNA display of PNA-tagged ligands: a versatile strategy to screen libraries and control geometry of multidentate ligands.

    Science.gov (United States)

    Winssinger, Nicolas

    2012-07-01

    Over the past decade, several technologies have emerged to access nucleic acid-tagged libraries and select the fittest compound within such libraries. This perspective focuses on recent development with PNA-tagged small molecules displayed on DNA templates for screening purposes and to probe the optimal geometry in multivalent interactions.

  3. B-G cDNA clones have multiple small repeats and hybridize to both chicken MHC regions

    DEFF Research Database (Denmark)

    Kaufman, J; Salomonsen, J; Skjødt, K

    1989-01-01

    We used rabbit antisera to the chicken MHC erythrocyte molecule B-G and to the class I alpha chain (B-F) to screen lambda gt11 cDNA expression libraries made with RNA selected by oligo-dT from bone marrow cells of anemic B19 homozygous chickens. Eight clones were found to encode B-G molecules which...

  4. Construction and Identification of Full-length cDNA Library of the Peripheral Blood Leucocytes in Oreochromis niloticus after Vaccination%尼罗罗非鱼免疫后外周血白细胞全长cDNA文库的构建及鉴定

    Institute of Scientific and Technical Information of China (English)

    陈明; 梁万文; 李超; 王瑞; 李莉萍; 甘西; 余晓丽; 雷爱莹; 黄婷; 陈福艳

    2011-01-01

    ( blue/white) was determined , and 24 clones were picked randomly from the library for screening size of cDNA inserts through PCR reaction. By identification, the primary constructed cDNA library contained 1.021 × 106 independent clones. The titer of the cDNA library was estimated as 1. 078 × 106/mL. the recombinant rate was above 94.71 %. The inserts varied from 0.7 to 3.0 kb with average size was about 1500 bp. 24 clones were sequenced randomly-selected from each lihrary and 18 contigs were acquired and analyzed by BLASTx. The resulta indicated that 15 contigs had the homologous gene information which 10 were full-length cDNA with 66. 7 % of full-ratio. These results shoWed that the full-length cDNA library meet the requirement of a standard full-length cDNA library. and it could lay a strong basis for subsequent work of clone and selection of some immune functional genes.

  5. A Microfluidic Platform for High-Throughput Screening of Small Mutant Libraries.

    Science.gov (United States)

    Lim, Ji Won; Shin, Kwang Soo; Moon, Jaemin; Lee, Sung Kuk; Kim, Taesung

    2016-05-17

    The screening and isolation of target microorganisms from mutated recombinant libraries are crucial for the advancement of synthetic biology and metabolic engineering. However, conventional screening tools present several limitations in throughput, cost, and labor. Herein, we describe a novel microfluidic high-throughput screening (HTS) platform with several advantages. The platform utilizes a fluid array to compartmentalize bacterial cells in well-ordered separated microwells and allows long-term cell culture with high throughput. The platform enables the extraction of selected target cells from the fluid array for additional culture and postanalysis by using a capillary-driven sample relocation method. To confirm the feasibility of the platform, we demonstrated two different types of HTS methods based on the levels of reporter gene expression and cellular growth rate difference. For the reporter gene-based HTS, a spike recovery approach was taken to demonstrate that target cells are successfully screened out from a mixture containing nontarget cells by repeating the culture and extraction processes. Additionally, the same platform allowed us to screen and sort target cells according to their cellular growth rate difference, which seems hard in conventional screening methods. Hence, the platform could be used for various microbiological assays, including the detection of cell-excreted metabolites, microbial biosensors, and other HTS systems.

  6. Screening of peptide libraries against protective antigen of Bacillus anthracis in a disposable microfluidic cartridge.

    Directory of Open Access Journals (Sweden)

    Joshua M Kogot

    Full Text Available Bacterial surface peptide display has gained popularity as a method of affinity reagent generation for a wide variety of applications ranging from drug discovery to pathogen detection. In order to isolate the bacterial clones that express peptides with high affinities to the target molecule, multiple rounds of manual magnetic activated cell sorting (MACS followed by multiple rounds of fluorescence activated cell sorting (FACS are conventionally used. Although such manual methods are effective, alternative means of library screening which improve the reproducibility, reduce the cost, reduce cross contamination, and minimize exposure to hazardous target materials are highly desired for practical application. Toward this end, we report the first semi-automated system demonstrating the potential for screening bacterially displayed peptides using disposable microfluidic cartridges. The Micro-Magnetic Separation platform (MMS is capable of screening a bacterial library containing 3 × 10¹⁰ members in 15 minutes and requires minimal operator training. Using this system, we report the isolation of twenty-four distinct peptide ligands that bind to the protective antigen (PA of Bacilus anthracis in three rounds of selection. A consensus motif WXCFTC was found using the MMS and was also found in one of the PA binders isolated by the conventional MACS/FACS approach. We compared MMS and MACS rare cell recovery over cell populations ranging from 0.1% to 0.0000001% and found that both magnetic sorting methods could recover cells down to 0.0000001% initial cell population, with the MMS having overall lower standard deviation of cell recovery. We believe the MMS system offers a compelling approach towards highly efficient, semi-automated screening of molecular libraries that is at least equal to manual magnetic sorting methods and produced, for the first time, 15-mer peptide binders to PA protein that exhibit better affinity and specificity than peptides

  7. 玉米弯孢叶斑病菌酵母双杂交cDNA文库的构建及评价%Construction and characterization of yeast two hybrid cDNA library of Curvularia lunata

    Institute of Scientific and Technical Information of China (English)

    荆晶; 刘铜; 陈捷

    2012-01-01

    由新月弯孢[Curvularia lunata (Wakker)Boed]引起的玉米弯孢叶斑病是我国玉米生产区的一种重要性叶斑病,曾在20世纪90年代给我国玉米生产造成较大损失.目前对该病原菌致病类型鉴定与致病相关基因、病害发生规律、综合防治等方面均有较好的研究基础[1],并且在前期的研究中发现该病菌调控毒素形成的相关基因与色素合成相关基因在表达上存在某种关联性[2],由于这2个基因均为致病相关基因,因此研究两基因表达的蛋白的关联性对于全面揭示病菌致病机理和调控网络具有重要意义.%BD SMART technique and LD-PCR were applied to synthesize double strand cDNA(ds cDNA). The ds cDNA and pGADT7-Rec were transfered into competent yeast cell to construct yeast two-hybrid cDNA library of Curvularia lunata by homologous recombination method. The results showed that library capacitance was 2.46×105 and transformation rate was 2.13×105/μg pGADT7-Rec. The plaque titer of the library was 2.5×108 pfu/mL and the recombination frequency was 88. 24%. The length of inserted cDNA fragment was ranged from 0.4 kb to 3 kb in average. This is the first time to use BD SMART technique to construct yeast two-hybrid cDNA library of C. lunata by homologous recombination.

  8. Construction and analysis of a cDNA library from queen honeybee spermatheca gland%蜂王受精囊腺cDNA文库的构建与分析

    Institute of Scientific and Technical Information of China (English)

    李江红; 刘振; 欧阳昊; 彭文君; 梁勤

    2011-01-01

    Spermatheca is a tissue in queen honeybee for storing the sperm from the drone honeybee in copulation. The long term sperm storage in spermatheca is related to the secretion of spermathecal gland. Gene expression and regulation of spennathecal gland is a basement for understanding the mechanism of long term sperm storage. In this study, four hundred queen honeybees were reared artificially. The spermathecal gland of queen honeybee was dissected under microscope for isolating the total RNA and mRNA. The double strands cDNA were synthesized using the SMART ( switching mechanism at 5' end of RNA transcript) technology and then used to construct a cDNA library of spennathecal gland. The titre of the cDNA library was about 1.1× 106. The recombination rate of the cDNA library was over 99%. Many clones coding the spermathecal fluid protein were obtained by small scale sequencing and analyzing the cDNA library clones. Among them three clones coding the honeybee venom protein of apamin, secapinand icarapin, two major royal jelly protein clones ( MRJP8 and MRJP9) and testis enhanced gene transcript clone were also detected. These works will be helpful for understanding the mechanism of long term sperm storage in spermatheca.%从400只人工培育的处女蜂王中解剖受精囊及其腺体,利用其mRNA构建了一个cDNA文库.该文库的滴度为1.1×106,重组效率大于99%.进一步对文库克隆进行小规模测序和分析,获得了一批编码蜂王受精囊腺内溶蛋白的基因克隆,同时从中也检测到编码3种蜂毒蛋白(明肽、镇静肽和icarapin)、2种王浆蛋白(MRJP8-9)以及睾丸增强因子等克隆.

  9. A positive detecting code and its decoding algorithm for DNA library screening.

    Science.gov (United States)

    Uehara, Hiroaki; Jimbo, Masakazu

    2009-01-01

    The study of gene functions requires high-quality DNA libraries. However, a large number of tests and screenings are necessary for compiling such libraries. We describe an algorithm for extracting as much information as possible from pooling experiments for library screening. Collections of clones are called pools, and a pooling experiment is a group test for detecting all positive clones. The probability of positiveness for each clone is estimated according to the outcomes of the pooling experiments. Clones with high chance of positiveness are subjected to confirmatory testing. In this paper, we introduce a new positive clone detecting algorithm, called the Bayesian network pool result decoder (BNPD). The performance of BNPD is compared, by simulation, with that of the Markov chain pool result decoder (MCPD) proposed by Knill et al. in 1996. Moreover, the combinatorial properties of pooling designs suitable for the proposed algorithm are discussed in conjunction with combinatorial designs and d-disjunct matrices. We also show the advantage of utilizing packing designs or BIB designs for the BNPD algorithm.

  10. Library screening by means of mass spectrometry (MS) binding assays-exemplarily demonstrated for a pseudostatic library addressing γ-aminobutyric acid (GABA) transporter 1 (GAT1).

    Science.gov (United States)

    Sindelar, Miriam; Wanner, Klaus T

    2012-09-01

    In the present study, the application of mass spectrometry (MS) binding assays as a tool for library screening is reported. For library generation, dynamic combinatorial chemistry (DCC) was used. These libraries can be screened by means of MS binding assays when appropriate measures are taken to render the libraries pseudostatic. That way, the efficiency of MS binding assays to determine ligand binding in compound screening with the ease of library generation by DCC is combined. The feasibility of this approach is shown for γ-aminobutyric acid (GABA) transporter 1 (GAT1) as a target, representing the most important subtype of the GABA transporters. For the screening, hydrazone libraries were employed that were generated in the presence of the target by reacting various sets of aldehydes with a hydrazine derivative that is delineated from piperidine-3-carboxylic acid (nipecotic acid), a common fragment of known GAT1 inhibitors. To ensure that the library generated is pseudostatic, a large excess of the nipecotic acid derivative is employed. As the library is generated in a buffer system suitable for binding and the target is already present, the mixtures can be directly analyzed by MS binding assays-the process of library generation and screening thus becoming simple to perform. The binding affinities of the hits identified by deconvolution were confirmed in conventional competitive MS binding assays performed with single compounds obtained by separate synthesis. In this way, two nipecotic acid derivatives exhibiting a biaryl moiety, 1-{2-[2'-(1,1'-biphenyl-2-ylmethylidene)hydrazine]ethyl}piperidine-3-carboxylic acid and 1-(2-{2'-[1-(2-thiophenylphenyl)methylidene]hydrazine}ethyl)piperidine-3-carboxylic acid, were found to be potent GAT1 ligands exhibiting pK(i) values of 6.186 ± 0.028 and 6.229 ± 0.039, respectively. This method enables screening of libraries, whether generated by conventional chemistry or DCC, and is applicable to all kinds of targets including

  11. Physicochemical Profiles of the Marketed Agrochemicals and Clues for Agrochemical Lead Discovery and Screening Library Development.

    Science.gov (United States)

    Rao, Hanbing; Huangfu, Changxin; Wang, Yanying; Wang, Xianxiang; Tang, Tiansheng; Zeng, Xianyin; Li, Zerong; Chen, Yuzong

    2015-05-01

    Combinatorial chemistry, high-throughput and virtual screening technologies have been extensively used for discovering agrochemical leads from chemical libraries. The knowledge of the physicochemical properties of the marketed agrochemicals is useful for guiding the design and selection of such libraries. Since the earlier profiling of marketed agrochemicals, the number and types of marketed agrochemicals have significantly increased. Recent studies have shown the change of some physicochemical properties of oral drugs with time. There is a need to also profile the physicochemical properties of the marketed agrochemicals. In this work, we analyzed the key physicochemical properties of 1751 marketed agrochemicals in comparison with the previously-analyzed herbicides and insecticides, 106 391 natural products and 57 548 diverse synthetic libraries compounds. Our study revealed the distribution profiles and evolution trend of different types of agrochemicals that in many respects are broadly similar to the reported profiles for oral drugs, with the most marked difference being that agrochemicals have a lower number of hydrogen bond donors. The derived distribution patterns provided the rule of thumb guidelines for selecting potential agrochemical leads and also provided clues for further improving the libraries for agrochemical lead discovery.

  12. Newborn Screening: National Library of Medicine Literature Search, January 1980 through March 1987. No. 87-2.

    Science.gov (United States)

    Patrias, Karen

    This bibliography, prepared by the National Library of Medicine through a literature search of its online databases, covers all aspects of newborn screening. It includes references to screening for: inborn errors of metabolism, such as phenylketonuria and galactosemia; hemoglobinopathies, particularly sickle cell disease; congenital hypothyroidism…

  13. Analysis of expression sequence tags from a full-length-enriched cDNA library of developing sesame seeds (Sesamum indicum

    Directory of Open Access Journals (Sweden)

    Ke Tao

    2011-12-01

    Full Text Available Abstract Background Sesame (Sesamum indicum is one of the most important oilseed crops with high oil contents and rich nutrient value. However, genetic improvement efforts in sesame could not get benefit from molecular biology technology due to poor DNA and RNA sequence resources. In this study, we carried out a large scale of expressed sequence tags (ESTs sequencing from developing sesame seeds and further conducted analysis on seed storage products-related genes. Results A normalized and full-length enriched cDNA library from 5 ~ 30 days old immature seeds was constructed and randomly sequenced, leading to generation of 41,248 expressed sequence tags (ESTs which then formed 4,713 contigs and 27,708 singletons with 44.9% uniESTs being putative full-length open reading frames. Approximately 26,091 of all these uniESTs have significant matches to the counterparts in Nr database of GenBank, and 21,628 of them were assigned to one or more Gene ontology (GO terms. Homologous genes involved in oil biosynthesis were identified including some conservative transcription factors regulating oil biosynthesis such as LEAFY COTYLEDON1 (LEC1, PICKLE (PKL, WRINKLED1 (WRI1 and majority of them were found for the first time in sesame seeds. One hundred and 17 ESTs were identified possibly involved in biosynthesis of sesame lignans, sesamin and sesamolin. In total, 9,347 putative functional genes from developing seeds were identified, which accounts for one third of total genes in the sesame genome. Further analysis of the uniESTs identified 1,949 non-redundant simple sequence repeats (SSRs. Conclusions This study has provided an overview of genes expressed during sesame seed development. This collection of sesame full-length cDNAs covered a wide variety of genes in seeds, in particular, candidate genes involved in biosynthesis of sesame oils and lignans. These EST sequences enriched with full length will contribute to comparative genomic studies on sesame and

  14. Screening a Commercial Library of Pharmacologically Active Small Molecules against Staphylococcus aureus Biofilms.

    Science.gov (United States)

    Torres, Nelson S; Abercrombie, Johnathan J; Srinivasan, Anand; Lopez-Ribot, Jose L; Ramasubramanian, Anand K; Leung, Kai P

    2016-10-01

    It is now well established that bacterial infections are often associated with biofilm phenotypes that demonstrate increased resistance to common antimicrobials. Further, due to the collective attrition of new antibiotic development programs by the pharmaceutical industries, drug repurposing is an attractive alternative. In this work, we screened 1,280 existing commercially available drugs in the Prestwick Chemical Library, some with previously unknown antimicrobial activity, against Staphylococcus aureus, one of the commonly encountered causative pathogens of burn and wound infections. From the primary screen of the entire Prestwick Chemical Library at a fixed concentration of 10 μM, 104 drugs were found to be effective against planktonic S. aureus strains, and not surprisingly, these were mostly antimicrobials and antiseptics. The activity of 18 selected repurposing candidates, that is, drugs that show antimicrobial activity that are not already considered antimicrobials, observed in the primary screen was confirmed in dose-response experiments. Finally, a subset of nine of these drug candidates was tested against preformed biofilms of S. aureus We found that three of these drugs, niclosamide, carmofur, and auranofin, possessed antimicrobial activity against preformed biofilms, making them attractive candidates for repurposing as novel antibiofilm therapies.

  15. Inhibitors of neutrophil recruitment identified using transgenic zebrafish to screen a natural product library

    Directory of Open Access Journals (Sweden)

    Xingang Wang

    2014-01-01

    Full Text Available Cell migration is fundamental to the inflammatory response, but uncontrolled cell migration and excess recruitment of neutrophils and other leukocytes can cause damage to the tissue. Here we describe the use of an in vivo model – the Tg(mpx:GFPi114 zebrafish line, in which neutrophils are labelled by green fluorescent protein (GFP – to screen a natural product library for compounds that can affect neutrophil migratory behaviour. Among 1040 fungal extracts screened, two were found to inhibit neutrophil migration completely. Subfractionation of these extracts identified sterigmatocystin and antibiotic PF1052 as the active components. Using the EZ-TAXIScan chemotaxis assay, both compounds were also found to have a dosage-dependent inhibitory effect on murine neutrophil migration. Furthermore, neutrophils treated with PF1052 failed to form pseudopods and appeared round in shape, suggesting a defect in PI3-kinase (PI3K signalling. We generated a transgenic neutrophil-specific PtdIns(3,4,5P3 (PIP3 reporter zebrafish line, which revealed that PF1052 does not affect the activation of PI3K at the plasma membrane. In human neutrophils, PF1052 neither induced apoptosis nor blocked AKT phosphorylation. In conclusion, we have identified an antibiotic from a natural product library with potent anti-inflammatory properties, and have established the utility of the mpx:GFP transgenic zebrafish for high-throughput in vivo screens for novel inhibitors of neutrophil migration.

  16. Inhibitors of neutrophil recruitment identified using transgenic zebrafish to screen a natural product library.

    Science.gov (United States)

    Wang, Xingang; Robertson, Anne L; Li, Jingyu; Chai, Ruth Jinfen; Haishan, Wang; Sadiku, Pranvera; Ogryzko, Nikolay V; Everett, Martin; Yoganathan, Kanagasundaram; Luo, Hongbo Robert; Renshaw, Stephen A; Ingham, Philip W

    2014-01-01

    Cell migration is fundamental to the inflammatory response, but uncontrolled cell migration and excess recruitment of neutrophils and other leukocytes can cause damage to the tissue. Here we describe the use of an in vivo model - the Tg(mpx:GFP)(i114) zebrafish line, in which neutrophils are labelled by green fluorescent protein (GFP) - to screen a natural product library for compounds that can affect neutrophil migratory behaviour. Among 1040 fungal extracts screened, two were found to inhibit neutrophil migration completely. Subfractionation of these extracts identified sterigmatocystin and antibiotic PF1052 as the active components. Using the EZ-TAXIScan chemotaxis assay, both compounds were also found to have a dosage-dependent inhibitory effect on murine neutrophil migration. Furthermore, neutrophils treated with PF1052 failed to form pseudopods and appeared round in shape, suggesting a defect in PI3-kinase (PI3K) signalling. We generated a transgenic neutrophil-specific PtdIns(3,4,5)P3 (PIP3) reporter zebrafish line, which revealed that PF1052 does not affect the activation of PI3K at the plasma membrane. In human neutrophils, PF1052 neither induced apoptosis nor blocked AKT phosphorylation. In conclusion, we have identified an antibiotic from a natural product library with potent anti-inflammatory properties, and have established the utility of the mpx:GFP transgenic zebrafish for high-throughput in vivo screens for novel inhibitors of neutrophil migration.

  17. Discovery of antagonists of tick dopamine receptors via chemical library screening and comparative pharmacological analyses.

    Science.gov (United States)

    Ejendal, Karin F K; Meyer, Jason M; Brust, Tarsis F; Avramova, Larisa V; Hill, Catherine A; Watts, Val J

    2012-11-01

    Ticks transmit a wide variety of disease causing pathogens to humans and animals. Considering the global health impact of tick-borne diseases, there is a pressing need to develop new methods for vector control. We are exploring arthropod dopamine receptors as novel targets for insecticide/acaricide development because of their integral roles in neurobiology. Herein, we developed a screening assay for dopamine receptor antagonists to further characterize the pharmacological properties of the two D₁-like dopamine receptors (Isdop1 and Isdop2) identified in the Lyme disease vector, Ixodes scapularis, and develop a screening assay for receptor antagonists. A cell-based, cyclic AMP luciferase reporter assay platform was implemented to screen the LOPAC(1280) small molecule library for Isdop2 receptor antagonists, representing the first reported chemical library screen for any tick G protein-coupled receptor. Screening resulted in the identification of 85 "hit" compounds with antagonist activity at the Isdop2 receptor. Eight of these chemistries were selected for confirmation assays using a direct measurement of cAMP, and the effects on both Isdop1 and Isdop2 were studied for comparison. Each of these eight compounds showed antagonistic activity at both Isdop1 and Isdop2, although differences were observed regarding their relative potencies. Furthermore, comparison of the pharmacological properties of the tick dopamine receptors with that of the AaDOP2 receptor from the yellow fever mosquito and the human dopamine D₁ receptor (hD₁) revealed species-specific pharmacological profiles of these receptors. Compounds influencing dopaminergic functioning, such as the dopamine receptor antagonists discovered here, may provide lead chemistries for discovery of novel acaricides useful for vector control

  18. Fosmid library construction and screening for the maize mutant gene Vestigial glume 1

    Institute of Scientific and Technical Information of China (English)

    Chaoxian Liu; Xiaoli Liu; Lei Lei; Haiying Guan; Yilin Cai

    2016-01-01

    The maize mutant gene Vestigial glume 1 (Vg1) has been fine-mapped to a narrow region by map-based cloning and the candidate gene for Vg1 spanned 19.5 kb. Here we report Vg1 genomic fosmid library construction and screening. The fosmid library of Vg1 consisted of 574,000 clones with an average insert size of 36.4 kb, representing 7.9-fold coverage of the maize genome. Fosmid stability assays indicated that clones were stable during propagation in the fosmid system. Using Vg1 candidate gene-specific primers, a positive clone was successfully identified. This discovery will pave the way for identifying the function of Vg1 in maize development.

  19. Fosmid library construction and screening for the maize mutant gene Vestigial glume 1

    Institute of Scientific and Technical Information of China (English)

    Chaoxian Liu; Xiaoli Liu; Lei Lei; Haiying Guan; Yilin Cai

    2016-01-01

    The maize mutant gene Vestigial glume 1(Vg1) has been fine-mapped to a narrow region by map-based cloning and the candidate gene for Vg1 spanned 19.5 kb. Here we report Vg1 genomic fosmid library construction and screening. The fosmid library of Vg1 consisted of574,000 clones with an average insert size of 36.4 kb, representing 7.9-fold coverage of the maize genome. Fosmid stability assays indicated that clones were stable during propagation in the fosmid system. Using Vg1 candidate gene-specific primers, a positive clone was successfully identified. This discovery will pave the way for identifying the function of Vg1 in maize development.

  20. Fosmid library construction and screening for the maize mutant gene Vestigial glume 1

    Directory of Open Access Journals (Sweden)

    Chaoxian Liu

    2016-02-01

    Full Text Available The maize mutant gene Vestigial glume 1 (Vg1 has been fine-mapped to a narrow region by map-based cloning and the candidate gene for Vg1 spanned 19.5 kb. Here we report Vg1 genomic fosmid library construction and screening. The fosmid library of Vg1 consisted of 574,000 clones with an average insert size of 36.4 kb, representing 7.9-fold coverage of the maize genome. Fosmid stability assays indicated that clones were stable during propagation in the fosmid system. Using Vg1 candidate gene-specific primers, a positive clone was successfully identified. This discovery will pave the way for identifying the function of Vg1 in maize development.

  1. Phage-displayed peptide library screening for preferred human substrate peptide sequences for transglutaminase 7.

    Science.gov (United States)

    Kuramoto, Katsuma; Yamasaki, Risa; Shimizu, Yoshitaka; Tatsukawa, Hideki; Hitomi, Kiyotaka

    2013-09-01

    Transglutaminases are a family of enzymes that catalyze cross-linking reactions between proteins. Among the members, there is currently no information regarding the substrate preferences of transglutaminase 7 (TG7), that would clarify its physiological significance. We previously obtained several highly reactive substrate peptide sequences of transglutaminases from a random peptide library. In this study, we screened for preferred substrate sequences for TG7 from a phage-displayed 12-mer peptide library. The most preferred sequence was selected based on reactivity and isozyme specificity. We firstly exhibited the tendency for the preference of substrate sequence for TG7. Then, using the most efficient peptide, Z3S, we established an in vitro assay system to assess enzymatic activity of TG7.

  2. Inhibitors of VIM-2 by screening pharmacologically active and click-chemistry compound libraries.

    Science.gov (United States)

    Minond, Dmitriy; Saldanha, S Adrian; Subramaniam, Prem; Spaargaren, Michael; Spicer, Timothy; Fotsing, Joseph R; Weide, Timo; Fokin, Valery V; Sharpless, K Barry; Galleni, Moreno; Bebrone, Carine; Lassaux, Patricia; Hodder, Peter

    2009-07-15

    VIM-2 is an Ambler class B metallo-beta-lactamase (MBL) capable of hydrolyzing a broad-spectrum of beta-lactam antibiotics. Although the discovery and development of MBL inhibitors continue to be an area of active research, an array of potent, small molecule inhibitors is yet to be fully characterized for VIM-2. In the presented research, a compound library screening approach was used to identify and characterize VIM-2 inhibitors from a library of pharmacologically active compounds as well as a focused 'click' chemistry library. The four most potent VIM-2 inhibitors resulting from a VIM-2 screen were characterized by kinetic studies in order to determine K(i) and mechanism of enzyme inhibition. As a result, two previously described pharmacologic agents, mitoxantrone (1,4-dihydroxy-5,8-bis([2-([2-hydroxyethyl]amino)ethyl]amino)-9,10-anthracenedione) and 4-chloromercuribenzoic acid (pCMB) were found to be active, the former as a non-competitive inhibitor (K(i)=K(i)(')=1.5+/-0.2microM) and the latter as a slowly reversible or irreversible inhibitor. Additionally, two novel sulfonyl-triazole analogs from the click library were identified as potent, competitive VIM-2 inhibitors: N-((4-((but-3-ynyloxy)methyl)-1H-1,2,3-triazol-5-yl)methyl)-4-iodobenzenesulfonamide (1, K(i)=0.41+/-0.03microM) and 4-iodo-N-((4-(methoxymethyl)-1H-1,2,3-triazol-5-yl)methyl)benzenesulfonamide (2, K(i)=1.4+/-0.10microM). Mitoxantrone and pCMB were also found to potentiate imipenem efficacy in MIC and synergy assays employing Escherichia coli. Taken together, all four compounds represent useful chemical probes to further investigate mechanisms of VIM-2 inhibition in biochemical and microbiology-based assays.

  3. Construction of cDNA library and partial ESTs analysis of Strongylocentrotus intermedius%虾夷马粪海胆性腺cDNA文库构建及部分EST序列分析

    Institute of Scientific and Technical Information of China (English)

    丁君; 孙巍; 常亚青

    2011-01-01

    应用Gubler-Hoffman cDNA文库技术.构建虾夷马粪海胆(Strongylocentrotus intermedius)性腺cDNA文库.测试结果表明.其库容量为2.10x 106 PFU/mL.长度范围在0.54.2 kb.插人片段平均长度为1.4 kb.达到建库要求.对虾夷马粪海胆cDNA克隆测序.将获得的819条EST序列与NCB1数据库进行BLAST比对.获得了65个有研究价值的EST序列和cDN^克隆.其EST序列已提交到GenBank.序列号分别为G0448010-GO448016,GR410172-GR410229.虾夷马粪海胆性腺cDNA文库的成功构建.使短期内获得大量调控海胆性腺生长和营养性状的关键基因表达信息成为可能.为进一步开发海胆的生物资源提供参考.%Sea urchin(Strongylocentrotus intermedius) is a species of commercial and ecological significance, and as a economic species, sea urchin has been demanded steadily in Europe and Southeastern area for a long time.Recent studies focused on the development of its genomic resources, which is a key step towards further investigation, identification of gene and gene networks involved in its economic characters. Efforts have been focused on genes that can affect expression of important economic traits, such as growth and nutritional traits related genes. In this study, a cDNA library of sea urchin has been constructed from gonad using Gubler-Hoffman cDNA library technique. Total RNA was extracted from the grounded frozen powder of gonad tissue by using acid-guanidinephenol-chloroform (AGPC). Poly(A)+ RNA was isolated and purified by oligo(dT)18 anchor primer containing Not Ⅰ site. Both ends of the newly generated and polished double-stranded (ds) cDNA were attached by EcoR Ⅰ adaptors and the dscDNA was then restricted by Not Ⅰ. The short cDNA (<400 bp) was removed by Spin Column. The library consisted of 2.10× 106 PFU/mL colony forming units with average insert size of 1.4 kb, ranging from 0.5 kb to 4.2 kb and was quantified to construct a cDNA library. Eight hundred and fourteen ESTs were

  4. Construction of subtracted cDNA libraries of gastrocarcinoma and normal tissue with suppression subtractive hybridization and their quality analysis%人胃癌抑制消减cDNA文库的构建及文库质量分析

    Institute of Scientific and Technical Information of China (English)

    吴岚军; 毛秉智; 王升启

    2001-01-01

    Objective: To construct subtracted cDNA libraries of stomach tumors and normal stomach tissue using suppression subtractive hybridization(SSH).Methods: cDNA Library subtraction was performed using the protocol described in the Clontech PCR-Select cDNA Subtraction Kit. cDNA was synthesized from 2 μg of poly A+RNA from the tumor and normal tissues using AMV reverse transcriptase. The tester and driver cDNAs were digested with RsaⅠ, a four-base-cutting restriction enzyme that yields blunt ends. The tester cDNA was then subdivided into two portions, and each was ligated with different cDNA adaptor. Two hybridizations were performed. In the first, an excess of driver was added to each sample of tester. Hybridization kinetics led to equalization and enrichment of differentially expressed sequences. During the second hybridization, the two primary hybridization samples were mixed together without denaturing and thus the templates were generated from differentially expressed sequences for PCR amplification. Using suppression PCR, only differentially expressed sequences were amplified exponentially and after second PCR amplification the background was reduced and differentially expressed sequences were further enriched. The cDNAs were then directly inserted into a T/A cloning vector to generate a stomach tumor-specific subtracted cDNA library. Results: The amplified library contained 800 positive clones. Plasmid inserts were PCR amplified and showed 250-700 bp inserts. Conclusions: The successfully constructed subtracted cDNA library of gastrocarcinoma and normal tissue enables us to compare two populations of mRNA and obtain clones of genes that expressed in one population but not in the other.The characterization of these genes will allow them to be exploited for their diagnostic and therapeutic potentials.%目的:构建人胃癌抑制消减cDNA文库,为进一步大批量筛选、克隆胃癌特异性表达的基因奠定基础。方法:从胃癌和

  5. Construction and analysis of a subtracted cDNA library of Betula platyphylla female inflorescence%白桦雌花序cDNA消减文库的构建及分析

    Institute of Scientific and Technical Information of China (English)

    魏继承; 杨传平; 王超; 姜静

    2005-01-01

    为研究白桦雌花序花期基因表达情况,以两天为间隔对其进行取样.基于SMART策略,通过RT-PCR,将源自最后时期样品的cDNA作为Driver cDNA,源自其他时期样品的cDNA作为Tester cDNA,构建抑制性消减文库.EST序列经blastX分析表明,该文库中的基因大致可以归为五类,分别同代谢、物质运输和信号转导、细胞周期、胁迫反应及调控相关.本文对基因表达同发育的关系做了探讨.%Female inflorescence of Betula platyphylla was sampled at an interval of each two days to analyze the background of gene expression in floral phase. On the basis of SMART strategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA was from that of the others by RT-PCR which were subsequently used to construct a subtracted cDNA library. The result of the ESTs (expression sequence tags) blastX showed that the genes in the subtracted cDNA library could be mainly clustered into 5 groups related to metabolism, transportation and signal transduction, cell cycle, stress response, and regulation. The relationship between gene expression and development was also discussed.

  6. Construction of Midgut Tissue-Specific cDNA Library of Bombyx mandarina M. and Isolation and Sequence Analysis of Serine Protease Gene Fragment%野桑蚕中肠组织cDNA文库的构建及丝氨酸蛋白酶基因片段的克隆与序列分析

    Institute of Scientific and Technical Information of China (English)

    王燕红; 李兵; 王东; 朱莎; 赵华强; 卫正国; 沈卫德

    2008-01-01

    [Objective] The aim of the study is to construct cDNA library of midgut tissue of wild silkworm and isolate the serine protease gene. [Method] The midgut tissue-specific cDNA library of wild silkworm was constructed via cDNA Library Construction Kit (TaKaRa), then the serine protease gene was cloned via sequencing of the yielded cDNA library. [Result] The titer of cDNA library reached 6.2×105 pfu/ml, average insert size was about 1.2 kb. The serine protease gene cDNA fragment was obtained from colony sequencing (Accession No: EU672968). The nucleotide sequence of the cloned 854 bp fragment encodes 284 amino acid residues. Homology analyses showed some homology between putative amino acid sequence of the cloned fragment and amino acid sequences of serine proteases from other ten insects. [Conclusion] The results may avail to reveal the resistance of silkworm and wild silkworm to exotic intrusion.

  7. Characterization of cDNA encoding human placental anticoagulant protein (PP4): Homology with the lipocortin family

    Energy Technology Data Exchange (ETDEWEB)

    Grundmann, U.; Abel, K.J.; Bohn, H.; Loebermann, H.; Lottspeich, F.; Kuepper, H. (Research Institutes, Postfach (West Germany))

    1988-06-01

    A cDNA library prepared from human placenta was screened for sequences encoding the placental protein 4 (PP4). PP4 is an anticoagulant protein that acts as an indirect inhibitor of the thromboplastin-specific complex, which is involved in the blood coagulation cascade. Partial amino acid sequence information from PP4-derived cyanogen bromide fragments was used to design three oligonucleotide probes for screening the library. From 10{sup 6} independent recombinants, 18 clones were identified that hybridized to all three probes. These 18 recombinants contained cDNA inserts encoding a protein of 320 amino acid residues. In addition to the PP4 cDNA the authors identified 9 other recombinants encoding a protein with considerable similarity (74%) to PP4, which was termed PP4-X. PP4 and PP4-X belong to the lipocortin family, as judged by their homology to lipocortin I and calpactin I.

  8. Screening of genes related to sulfide metabolism in Urechis unicinctus (Echiura, Urechidae) using suppression subtractive hybridization and cDNA microarray analysis.

    Science.gov (United States)

    Shi, Xiaoli; Shao, Mingyu; Zhang, Litao; Ma, Yubin; Zhang, Zhifeng

    2012-09-01

    Exogenous sulfide can generally induce metabolic injuries in most organisms and even cause death. However, organisms inhabiting intertidal zones, hydrothermal vents, and cold seeps, can tolerate, metabolize, and utilize sulfide. In this study, both suppression subtractive hybridization and cDNA microarray analysis were employed to screen sulfide metabolism-related genes from the body wall in echiuran worm Urechis unicinctus, a marine sediment species. A total of 3456 monoclones were isolated and 82 were identified as differentially expressed genes in worms exposed to 50 μM sulfide for 24 h, compared to controls. The identified genes encoded proteins with multiple processes, including metabolism, cellular process, biological regulation, response to stimulus, multicellular organismal process, localization, development, and cellular component organization. Eight genes, serase, vacuolar protein, src tyrosine kinase, sulfide oxidase-like oxidoreductase, aprataxin, SN-RNP, aminopeptidase, and predicted protein, were selected to verify expression in the worm using qRT-PCR. The agreement of gene expression evaluation was 62.5% between the results of microarray analysis and qRT-PCR. These new data will provide clues for further probing of the molecular mechanism of sulfide metabolism.

  9. Identification of potent Yes1 kinase inhibitors using a library screening approach.

    Science.gov (United States)

    Patel, Paresma R; Sun, Hongmao; Li, Samuel Q; Shen, Min; Khan, Javed; Thomas, Craig J; Davis, Mindy I

    2013-08-01

    Yes1 kinase has been implicated as a potential therapeutic target in a number of cancers including melanomas, breast cancers, and rhabdomyosarcomas. Described here is the development of a robust and miniaturized biochemical assay for Yes1 kinase that was applied in a high throughput screen (HTS) of kinase-focused small molecule libraries. The HTS provided 144 (17% hit rate) small molecule compounds with IC₅₀ values in the sub-micromolar range. Three of the most potent Yes1 inhibitors were then examined in a cell-based assay for inhibition of cell survival in rhabdomyosarcoma cell lines. Homology models of Yes1 were generated in active and inactive conformations, and docking of inhibitors supports binding to the active conformation (DFG-in) of Yes1. This is the first report of a large high throughput enzymatic activity screen for identification of Yes1 kinase inhibitors, thereby elucidating the polypharmacology of a variety of small molecules and clinical candidates.

  10. Histidine-containing peptide catalysts developed by a facile library screening method.

    Science.gov (United States)

    Akagawa, Kengo; Sakai, Nobutaka; Kudo, Kazuaki

    2015-02-02

    Although peptide catalysts have a high potential for the use as organocatalysts, the optimization of peptide sequences is laborious and time-consuming. To address this issue, a facile screening method for finding efficient aminocatalysts from a peptide library has been developed. In the screening for the Michael addition of a malonate to an enal, a dye-labeled product is immobilized on resin-bound peptides through reductive amination to visualize active catalysts. This procedure allows for the monitoring of the reactivity of entire peptides without modifying the resin beads beforehand. Peptides containing histidine at an appropriate position were identified by this method. A novel function of the histidyl residue, which enhances the binding of a substrate to the catalyst by capturing an iminium intermediate, was indicated.

  11. High-throughput screening of small molecule libraries using SAMDI mass spectrometry.

    Science.gov (United States)

    Gurard-Levin, Zachary A; Scholle, Michael D; Eisenberg, Adam H; Mrksich, Milan

    2011-07-11

    High-throughput screening is a common strategy used to identify compounds that modulate biochemical activities, but many approaches depend on cumbersome fluorescent reporters or antibodies and often produce false-positive hits. The development of "label-free" assays addresses many of these limitations, but current approaches still lack the throughput needed for applications in drug discovery. This paper describes a high-throughput, label-free assay that combines self-assembled monolayers with mass spectrometry, in a technique called SAMDI, as a tool for screening libraries of 100,000 compounds in one day. This method is fast, has high discrimination, and is amenable to a broad range of chemical and biological applications.

  12. Isolation of xylose isomerases by sequence- and function-based screening from a soil metagenomic library

    Directory of Open Access Journals (Sweden)

    Parachin Nádia

    2011-05-01

    Full Text Available Abstract Background Xylose isomerase (XI catalyses the isomerisation of xylose to xylulose in bacteria and some fungi. Currently, only a limited number of XI genes have been functionally expressed in Saccharomyces cerevisiae, the microorganism of choice for lignocellulosic ethanol production. The objective of the present study was to search for novel XI genes in the vastly diverse microbial habitat present in soil. As the exploitation of microbial diversity is impaired by the ability to cultivate soil microorganisms under standard laboratory conditions, a metagenomic approach, consisting of total DNA extraction from a given environment followed by cloning of DNA into suitable vectors, was undertaken. Results A soil metagenomic library was constructed and two screening methods based on protein sequence similarity and enzyme activity were investigated to isolate novel XI encoding genes. These two screening approaches identified the xym1 and xym2 genes, respectively. Sequence and phylogenetic analyses revealed that the genes shared 67% similarity and belonged to different bacterial groups. When xym1 and xym2 were overexpressed in a xylA-deficient Escherichia coli strain, similar growth rates to those in which the Piromyces XI gene was expressed were obtained. However, expression in S. cerevisiae resulted in only one-fourth the growth rate of that obtained for the strain expressing the Piromyces XI gene. Conclusions For the first time, the screening of a soil metagenomic library in E. coli resulted in the successful isolation of two active XIs. However, the discrepancy between XI enzyme performance in E. coli and S. cerevisiae suggests that future screening for XI activity from soil should be pursued directly using yeast as a host.

  13. A high throughput screen for biomining cellulase activity from metagenomic libraries.

    Science.gov (United States)

    Mewis, Keith; Taupp, Marcus; Hallam, Steven J

    2011-02-01

    Cellulose, the most abundant source of organic carbon on the planet, has wide-ranging industrial applications with increasing emphasis on biofuel production (1). Chemical methods to modify or degrade cellulose typically require strong acids and high temperatures. As such, enzymatic methods have become prominent in the bioconversion process. While the identification of active cellulases from bacterial and fungal isolates has been somewhat effective, the vast majority of microbes in nature resist laboratory cultivation. Environmental genomic, also known as metagenomic, screening approaches have great promise in bridging the cultivation gap in the search for novel bioconversion enzymes. Metagenomic screening approaches have successfully recovered novel cellulases from environments as varied as soils (2), buffalo rumen (3) and the termite hind-gut (4) using carboxymethylcellulose (CMC) agar plates stained with congo red dye (based on the method of Teather and Wood (5)). However, the CMC method is limited in throughput, is not quantitative and manifests a low signal to noise ratio (6). Other methods have been reported (7,8) but each use an agar plate-based assay, which is undesirable for high-throughput screening of large insert genomic libraries. Here we present a solution-based screen for cellulase activity using a chromogenic dinitrophenol (DNP)-cellobioside substrate (9). Our library was cloned into the pCC1 copy control fosmid to increase assay sensitivity through copy number induction (10). The method uses one-pot chemistry in 384-well microplates with the final readout provided as an absorbance measurement. This readout is quantitative, sensitive and automated with a throughput of up to 100X 384-well plates per day using a liquid handler and plate reader with attached stacking system.

  14. New screening software shows that most recent large 16S rRNA gene clone libraries contain chimeras.

    Science.gov (United States)

    Ashelford, Kevin E; Chuzhanova, Nadia A; Fry, John C; Jones, Antonia J; Weightman, Andrew J

    2006-09-01

    A new computer program, called Mallard, is presented for screening entire 16S rRNA gene libraries of up to 1,000 sequences for chimeras and other artifacts. Written in the Java computer language and capable of running on all major operating systems, the program provides a novel graphical approach for visualizing phylogenetic relationships among 16S rRNA gene sequences. To illustrate its use, we analyzed most of the large libraries of cloned bacterial 16S rRNA gene sequences submitted to the public repository during 2005. Defining a large library as one containing 100 or more sequences of 1,200 bases or greater, we screened 25 of the 28 libraries and found that all but three contained substantial anomalies. Overall, 543 anomalous sequences were found. The average anomaly content per clone library was 9.0%, 4% higher than that previously estimated for the public repository overall. In addition, 90.8% of anomalies had characteristic chimeric patterns, a rise of 25.4% over that found previously. One library alone was found to contain 54 chimeras, representing 45.8% of its content. These figures far exceed previous estimates of artifacts within public repositories and further highlight the urgent need for all researchers to adequately screen their libraries prior to submission. Mallard is freely available from our website at http://www.cardiff.ac.uk/biosi/research/biosoft/.

  15. Emulsion culture: a miniaturized library screening system based on micro-droplets in an emulsified medium.

    Science.gov (United States)

    Kojima, Takaaki; Nagao, Nobuhito; Ando, Daisuke; Ojima, Teruyo; Kawarasaki, Yasuaki; Kobayashi, Isao; Nakajima, Mitsutoshi; Nakano, Hideo

    2011-09-01

    A typical library screen in directed evolution primarily requires physical separation of the clones on agar plates followed by detection of clones with improved properties; using this method only limited numbers of clones relative to the number of potential variations can be assessed. In particular, screening for a secretory enzyme is difficult to perform at high clone density, because of diffusion of the signal or unfavorable utilization of the reaction product by neighboring clones. In this study, we have developed a novel method of enrichment culture: "Emulsion Culture", i.e., segregated replication of clones in an emulsified culture medium. Clones expressing enzyme-variants are separately distributed to small (up to 50 μm in diameter), segregated compartments composed of a droplet of medium to form several tens of millions of microcolonies in a milliliter of medium, which allows a miniaturized, in-bulk screening of clones. We applied this culture method to yeast clones expressing secretory beta-galactosidase to analyze the enrichment factor achieved. A high-density screen for a signal peptide sequence that maximizes extracellular production of the enzyme was also performed to demonstrate the practicability of this culture method. In addition, micro-channel emulsification was tested as a method of forming uniformly-sized compartments in the emulsion.

  16. Construction of differentially expressed cDNA libraries of aldehyde dehydrogenase with high and low activity from tongue squamous carcinoma Tca8113 cell line%基于舌鳞癌Tca8113细胞醛脱氢酶活性不同构建差异表达基因cDNA文库

    Institute of Scientific and Technical Information of China (English)

    孙守娟; 季平; 邓诚; 李颖; 邹波; 漆小娟

    2012-01-01

    Objective To construct the differentially expressed cDNA libraries of aldehyde dehydro genase with high and low activity (ALDHhigh/ALDHlow) from tongue squamous carcinoma Tca8113 cell line. Methods Expression of stem cell marker ALDH was detected, and ALDHhighand ALDHlow cells were collected by Aldefluor assay combined with flow cytometry. Differentially expressed genes of total RNA that was extracted from the two cell subpopulations by Trizol were screened and amplified by suppressing subtractive hybridization ( SSH) , and the PCR products were connected with pMD18-T vector and then transfected into E. Coli DH5a for amplification. Enzyme digestion, gene sequencing and homology analysis were performed in 24 positive clones that were randomly picked from each library. Results Two subproportions of ALDHhigh and ALDHlowwere " screened out, and ALDHhigh cells in Tca8113 cells accounted for 2. 5%. RNA D(260)/D(280) of ALDHhigh and ALDHlow were 1. 93 and 1. 92, respectively. Two-directional subtractive cDNA libraries of ALDHhigh and ALDHlow were constructed, and each library comprised 500 clones. PCR analysis of 24 clones randomly picked from each library showed that insert-fragments distributed in 200 - 700 bp, and no false positive clones were detected. Gene sequencing result that was analyzed and indexed by PubMed showed that cancer related genes included SLC25A13, KLHL2, NPC1, WAPL, BARD1, Notch2 and EEF2K. Conclusion Two-directional subtractive cDNA libraries of ALDHhigh and ALDHlow cells were successfully constructed.%目的 构建舌鳞癌Tca8113细胞系中高、低醛脱氢酶活性(high/low aldehyde dehydrogenase activity,ALDHhigh/ALDHlow)细胞差异表达基因cDNA文库.方法 用流式细胞仪检测ALDEFLUOR(R)染色的Tca8113细胞中干细胞标志物ALDH的表达,并收集ALDHhigh和ALDHlow细胞;用Trizol分别提取两亚群细胞的总RNA;用抑制性消减杂交(SSH)对2组RNA进行差异基因筛选和扩增,扩增产物与pMD18-T载体

  17. NCBI和cDNA文库中栽培花生EST-SSR分子标记的开发及其特点%Development and Characterization of EST-SSR Markers from NCBI and cDNA Library in Cultivated Peanut (Arachis hypogaea L.)

    Institute of Scientific and Technical Information of China (English)

    王金彦; 潘丽娟; 杨庆利; 禹山林

    2009-01-01

    86 132 ESTs downloaded from GenBank in NCBI and 12 501 ESTs from cDNA library constructed by high-oil linoleic acid accession E 12 were analysed. After the preprocession, there were 18 051 singletons and 9 972 contigs in the GenBank of NCBI and cDNA library. Totally 3 104 SSR loci had been screened by MISA software, accounting for 11.08% for these non-redundant ESTs. All SSR loci are divided into di-nucleotide, thi-nucleotide, tetra-nucleotide, penta-nucleotide, hexa-nucleotide and multi-nucleotide etc., and thi-nucleotide motif is the most motifs and the frequency was 43.0% and 56.8% in NCBI and cDNA libraray, respectively. The number of di-and penta-nucleotide motifs were second and third in all motifs. And the hexa-nucleotide was the least mo-tif both in NCBI and cDNA library. In all repeat motifs nucleotide, AG/TC was the most motifs and accounted for 8.65% and 13.42% in NCBI and cDNA library, respectively. Among the tri-nucleotide repeats, CTT/GAA was the most frequent motif, accounting for 6.7% and 13.42%, respectively. The repeat unit number of SSR loci is from 4 to 51.%本研究利用NCBI的GenBank数据库中公布的花生86 132条EST序列以及利用高油酸品种E12所创建的cDNA文库中的12 501条EST序列,对这些序列进行前期处理,总共获得非冗余且拼接较长的singleton 11 260条,contig 9 972条.通过MISA软件分析发现两个EST库中共包含有3 104个SSR位点,占到总共非冗余序列的11.08%.这些SSR位点被分成二核苷酸重复、三核苷酸重复、四核苷酸重复、五核苷酸重复、六核苷酸重复以及混合核苷酸重复等,其中三核苷酸重复占的比例最多,分别占到NCBI和cDNA文库的43.0%和56.8%,二核苷酸和五核苷酸重复占到所有重复位点的第二位和第三位,六核苷酸重复的比例最少.在所有重复基序中,AG/TC重复的数量最多,分别占到NCBI和cDNA文库的8.65%和13.42%.在三核苷酸重复中,CTT/GAA出现的频率最大,分别占到6.7%

  18. Construction of Subtracted cDNA Library of the Early Growth Plate in Broiler Chickens with Thiram-induced Tibial Dyschondroplasia%福美双诱发肉鸡胫骨软骨发育不良早期生长板消减cDNA文库的构建

    Institute of Scientific and Technical Information of China (English)

    宁官保; 郭定宗; 田文霞; 王瑞; 覃平; 乔建钢; 李宏全; 李家奎; 毕丁仁; 潘思轶

    2011-01-01

    [Objective] An experiment was conducted to construct subtracted cDNA library for selecting time series genes differentially expressed in the TD growth plate of broiler chickens at the early stage with cDNA microarray. [Method] AVIAN (AV) broiler chicks at 7 days of age were randomly divided into two groups. After fasting overnight, they were fed with regular diet (control) or the same diet containing 100 mg/kg thiram for 48h to induce TD (thiram diet-fed). Forward and reverse-subtracted eDNA libraries were generated by suppression subtractive hybridization technology (SSH). Identification of the inserted cDNA fragments in subtractive library was done using PCR. One hundred clones were randomly selected for further DNA sequencing, blast homology analysis and function prediction. [Result] A total of 2 227 positive clones were obtained and the size of inserts was between 200 bp and 1 000 bp. There were 97 homologous gene sequences shared more than 99% identity with genes known in chicken (Gallus gallus). Non-redundancy of sequenced genes was 68.7%. Meanwhile, 3 clones were found to be novel EST as no functional clues were associated with them by bioinformatic analysis. Most of these genes are involved in matrix formation,endochondral ossification and remodelling, developmental regulation, signal transduction, electron transport in mitochondrial respiratory chain and vascularization. [ Conclusion ] Successfully produced cDNA library would make a good foundation for further printing cDNA microarray, screening differential expression genes of TD growth plates at different stages, and also may provide new insights into understanding the pathogenesis of TD.%[目的]为应用cDNA芯片技术筛选肉鸡胫骨软骨发育不良(TD)时序性差异表达基因,本研究构建了早期生长板消减cDNA文库.[方法]将7日龄AV肉鸡随机分为两组,对照组(control,C)饲以基础日粮,试验组(thiram diet-fed,T)饲以基础日粮添加福美双100 mg·kg(-1),2 d

  19. Novel protein kinase signaling systems regulating lifespan identified by small molecule library screening using Drosophila.

    Directory of Open Access Journals (Sweden)

    Stephen R Spindler

    Full Text Available Protein kinase signaling cascades control most aspects of cellular function. The ATP binding domains of signaling protein kinases are the targets of most available inhibitors. These domains are highly conserved from mammals to flies. Herein we describe screening of a library of small molecule inhibitors of protein kinases for their ability to increase Drosophila lifespan. We developed an assay system which allowed screening using the small amounts of materials normally present in commercial chemical libraries. The studies identified 17 inhibitors, the majority of which targeted tyrosine kinases associated with the epidermal growth factor receptor (EGFR, platelet-derived growth factor (PDGF/vascular endothelial growth factor (VEGF receptors, G-protein coupled receptor (GPCR, Janus kinase (JAK/signal transducer and activator of transcription (STAT, the insulin and insulin-like growth factor (IGFI receptors. Comparison of the protein kinase signaling effects of the inhibitors in vitro defined a consensus intracellular signaling profile which included decreased signaling by p38MAPK (p38, c-Jun N-terminal kinase (JNK and protein kinase C (PKC. If confirmed, many of these kinases will be novel additions to the signaling cascades known to regulate metazoan longevity.

  20. A new age in functional genomics using CRISPR/Cas9 in arrayed library screening.

    Science.gov (United States)

    Agrotis, Alexander; Ketteler, Robin

    2015-01-01

    CRISPR technology has rapidly changed the face of biological research, such that precise genome editing has now become routine for many labs within several years of its initial development. What makes CRISPR/Cas9 so revolutionary is the ability to target a protein (Cas9) to an exact genomic locus, through designing a specific short complementary nucleotide sequence, that together with a common scaffold sequence, constitute the guide RNA bridging the protein and the DNA. Wild-type Cas9 cleaves both DNA strands at its target sequence, but this protein can also be modified to exert many other functions. For instance, by attaching an activation domain to catalytically inactive Cas9 and targeting a promoter region, it is possible to stimulate the expression of a specific endogenous gene. In principle, any genomic region can be targeted, and recent efforts have successfully generated pooled guide RNA libraries for coding and regulatory regions of human, mouse and Drosophila genomes with high coverage, thus facilitating functional phenotypic screening. In this review, we will highlight recent developments in the area of CRISPR-based functional genomics and discuss potential future directions, with a special focus on mammalian cell systems and arrayed library screening.

  1. A New Age in Functional Genomics Using CRISPR/Cas9 in Arrayed Library Screening

    Directory of Open Access Journals (Sweden)

    Alexander eAgrotis

    2015-09-01

    Full Text Available CRISPR technology has rapidly changed the face of biological research, such that precise genome editing has now become routine for many labs within several years of its initial development. What makes CRISPR/Cas9 so revolutionary is the ability to target a protein (Cas9 to an exact genomic locus, through designing a specific short complementary nucleotide sequence, that together with a common scaffold sequence, constitute the guide RNA bridging the protein and the DNA. Wild-type Cas9 cleaves both DNA strands at its target sequence, but this protein can also be modified to exert many other functions. For instance, by attaching an activation domain to catalytically inactive Cas9 and targeting a promoter region, it is possible to stimulate the expression of a specific endogenous gene. In principle, any genomic region can be targeted, and recent efforts have successfully generated pooled guide RNA libraries for coding and regulatory regions of human, mouse and Drosophila genomes with high coverage, thus facilitating functional phenotypic screening. In this review, we will highlight recent developments in the area of CRISPR-based functional genomics and discuss potential future directions, with a special focus on mammalian cell systems and arrayed library screening.

  2. Epitope prediction based on random peptide library screening: benchmark dataset and prediction tools evaluation.

    Science.gov (United States)

    Sun, Pingping; Chen, Wenhan; Huang, Yanxin; Wang, Hongyan; Ma, Zhiqiang; Lv, Yinghua

    2011-06-16

    Epitope prediction based on random peptide library screening has become a focus as a promising method in immunoinformatics research. Some novel software and web-based servers have been proposed in recent years and have succeeded in given test cases. However, since the number of available mimotopes with the relevant structure of template-target complex is limited, a systematic evaluation of these methods is still absent. In this study, a new benchmark dataset was defined. Using this benchmark dataset and a representative dataset, five examples of the most popular epitope prediction software products which are based on random peptide library screening have been evaluated. Using the benchmark dataset, in no method did performance exceed a 0.42 precision and 0.37 sensitivity, and the MCC scores suggest that the epitope prediction results of these software programs are greater than random prediction about 0.09-0.13; while using the representative dataset, most of the values of these performance measures are slightly improved, but the overall performance is still not satisfactory. Many test cases in the benchmark dataset cannot be applied to these pieces of software due to software limitations. Moreover chances are that these software products are overfitted to the small dataset and will fail in other cases. Therefore finding the correlation between mimotopes and genuine epitope residues is still far from resolved and much larger dataset for mimotope-based epitope prediction is desirable.

  3. Epitope Prediction Based on Random Peptide Library Screening: Benchmark Dataset and Prediction Tools Evaluation

    Directory of Open Access Journals (Sweden)

    Yanxin Huang

    2011-06-01

    Full Text Available Epitope prediction based on random peptide library screening has become a focus as a promising method in immunoinformatics research. Some novel software and web-based servers have been proposed in recent years and have succeeded in given test cases. However, since the number of available mimotopes with the relevant structure of template-target complex is limited, a systematic evaluation of these methods is still absent. In this study, a new benchmark dataset was defined. Using this benchmark dataset and a representative dataset, five examples of the most popular epitope prediction software products which are based on random peptide library screening have been evaluated. Using the benchmark dataset, in no method did performance exceed a 0.42 precision and 0.37 sensitivity, and the MCC scores suggest that the epitope prediction results of these software programs are greater than random prediction about 0.09–0.13; while using the representative dataset, most of the values of these performance measures are slightly improved, but the overall performance is still not satisfactory. Many test cases in the benchmark dataset cannot be applied to these pieces of software due to software limitations. Moreover chances are that these software products are overfitted to the small dataset and will fail in other cases. Therefore finding the correlation between mimotopes and genuine epitope residues is still far from resolved and much larger dataset for mimotope-based epitope prediction is desirable.

  4. Novel protein kinase signaling systems regulating lifespan identified by small molecule library screening using Drosophila.

    Science.gov (United States)

    Spindler, Stephen R; Li, Rui; Dhahbi, Joseph M; Yamakawa, Amy; Sauer, Frank

    2012-01-01

    Protein kinase signaling cascades control most aspects of cellular function. The ATP binding domains of signaling protein kinases are the targets of most available inhibitors. These domains are highly conserved from mammals to flies. Herein we describe screening of a library of small molecule inhibitors of protein kinases for their ability to increase Drosophila lifespan. We developed an assay system which allowed screening using the small amounts of materials normally present in commercial chemical libraries. The studies identified 17 inhibitors, the majority of which targeted tyrosine kinases associated with the epidermal growth factor receptor (EGFR), platelet-derived growth factor (PDGF)/vascular endothelial growth factor (VEGF) receptors, G-protein coupled receptor (GPCR), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), the insulin and insulin-like growth factor (IGFI) receptors. Comparison of the protein kinase signaling effects of the inhibitors in vitro defined a consensus intracellular signaling profile which included decreased signaling by p38MAPK (p38), c-Jun N-terminal kinase (JNK) and protein kinase C (PKC). If confirmed, many of these kinases will be novel additions to the signaling cascades known to regulate metazoan longevity.

  5. Synthetic biology approaches to improve biocatalyst identification in metagenomic library screening.

    Science.gov (United States)

    Guazzaroni, María-Eugenia; Silva-Rocha, Rafael; Ward, Richard John

    2015-01-01

    There is a growing demand for enzymes with improved catalytic performance or tolerance to process-specific parameters, and biotechnology plays a crucial role in the development of biocatalysts for use in industry, agriculture, medicine and energy generation. Metagenomics takes advantage of the wealth of genetic and biochemical diversity present in the genomes of microorganisms found in environmental samples, and provides a set of new technologies directed towards screening for new catalytic activities from environmental samples with potential biotechnology applications. However, biased and low level of expression of heterologous proteins in Escherichia coli together with the use of non-optimal cloning vectors for the construction of metagenomic libraries generally results in an extremely low success rate for enzyme identification. The bottleneck arising from inefficient screening of enzymatic activities has been addressed from several perspectives; however, the limitations related to biased expression in heterologous hosts cannot be overcome by using a single approach, but rather requires the synergetic implementation of multiple methodologies. Here, we review some of the principal constraints regarding the discovery of new enzymes in metagenomic libraries and discuss how these might be resolved by using synthetic biology methods.

  6. First siRNA library screening in hard-to-transfect HUVEC cells.

    Science.gov (United States)

    Zumbansen, Markus; Altrogge, Ludger M; Spottke, Nicole Ue; Spicker, Sonja; Offizier, Sheila M; Domzalski, Sandra Bs; St Amand, Allison L; Toell, Andrea; Leake, Devin; Mueller-Hartmann, Herbert A

    2009-10-29

    Meaningful RNAi-based data for target gene identification are strongly dependent on the use of a biologically relevant cell type and efficient delivery of highly functional siRNA reagents into the selected cell type. Here we report the use of the Amaxa(R) Nucleofector(R) 96-well Shuttle(R) System for siRNA screening in primary cells. Lonza's Clonetics(R) HUVEC-Human Umbilical Vein Endothelial Cells were transfected with Thermo Scientific Dharmacon siGENOME(R) siRNA Libraries targeting protein kinases and cell cycle related genes and screened for genes important for cell viability. Of the 37 primary hits, down-regulation of 33 led to reduced proliferation or increased cell death, while down-regulation of two allowed for better cell viability. The validated four genes out of the 16 strongest primary hits (COPB2, PYCS, CDK4 and MYC) influenced cell proliferation to varying degrees, reflecting differing importance for survival of HUVEC cells. Our results demonstrate that the Nucleofector(R) 96-well Shuttle(R) System allows the delivery of siRNA libraries in cell types previously considered to be difficult to transfect. Thus, identification and validation of gene targets can now be conducted in primary cells, as the selection of cell types is not limited to those accessible by lipid-mediated transfection.

  7. Construction and screening of a functional metagenomic library to identify novel enzymes produced by Antarctic bacteria

    Institute of Scientific and Technical Information of China (English)

    Ignacio Ferrés; Vanesa Amarelle; Francisco Noya; Elena Fabiano

    2015-01-01

    A metagenomic fosmid library of approximately 52 000 clones was constructed to identify functional genes encoding cold-adapted enzymes. Metagenomic DNA was extracted from a sample of glacial meltwater, collected on the Antarctic Peninsula during the ANTARKOS XXIX Expedition during the austral summer of 2012–2013. Each clone contained an insert of about 35–40 kb, so the library represented almost 2 Gb of genetic information from metagenomic DNA. Activity-driven screening was used to detect the cold-adapted functions expressed by the library. Fifty lipase/esterase and two cellulase-producing clones were isolated, and two clones able to grow on Avicel® as the sole carbon source. Interestingly, three clones formed a brown precipitate in the presence of manganese (II). Accumulation of manganese oxides was determined with a leucoberbelin blue assay, indicating that these three clones had manganese-oxidizing activity. To the best of our knowledge, this is the first report of a manganese oxidase activity detected with a functional metagenomic strategy.

  8. Functional Screening of Antibiotic Resistance Genes from a Representative Metagenomic Library of Food Fermenting Microbiota

    Directory of Open Access Journals (Sweden)

    Chiara Devirgiliis

    2014-01-01

    Full Text Available Lactic acid bacteria (LAB represent the predominant microbiota in fermented foods. Foodborne LAB have received increasing attention as potential reservoir of antibiotic resistance (AR determinants, which may be horizontally transferred to opportunistic pathogens. We have previously reported isolation of AR LAB from the raw ingredients of a fermented cheese, while AR genes could be detected in the final, marketed product only by PCR amplification, thus pointing at the need for more sensitive microbial isolation techniques. We turned therefore to construction of a metagenomic library containing microbial DNA extracted directly from the food matrix. To maximize yield and purity and to ensure that genomic complexity of the library was representative of the original bacterial population, we defined a suitable protocol for total DNA extraction from cheese which can also be applied to other lipid-rich foods. Functional library screening on different antibiotics allowed recovery of ampicillin and kanamycin resistant clones originating from Streptococcus salivarius subsp. thermophilus and Lactobacillus helveticus genomes. We report molecular characterization of the cloned inserts, which were fully sequenced and shown to confer AR phenotype to recipient bacteria. We also show that metagenomics can be applied to food microbiota to identify underrepresented species carrying specific genes of interest.

  9. A transcription blocker isolated from a designed repeat protein combinatorial library by in vivo functional screen.

    Science.gov (United States)

    Tikhonova, Elena B; Ethayathulla, Abdul S; Su, Yue; Hariharan, Parameswaran; Xie, Shicong; Guan, Lan

    2015-01-28

    A highly diverse DNA library coding for ankyrin seven-repeat proteins (ANK-N5C) was designed and constructed by a PCR-based combinatorial assembly strategy. A bacterial melibiose fermentation assay was adapted for in vivo functional screen. We isolated a transcription blocker that completely inhibits the melibiose-dependent expression of α-galactosidase (MelA) and melibiose permease (MelB) of Escherichia coli by specifically preventing activation of the melAB operon. High-resolution crystal structural determination reveals that the designed ANK-N5C protein has a typical ankyrin fold, and the specific transcription blocker, ANK-N5C-281, forms a domain-swapped dimer. Functional tests suggest that the activity of MelR, a DNA-binding transcription activator and a member of AraC family of transcription factors, is inhibited by ANK-N5C-281 protein. All ANK-N5C proteins are expected to have a concave binding area with negative surface potential, suggesting that the designed ANK-N5C library proteins may facilitate the discovery of binders recognizing structural motifs with positive surface potential, like in DNA-binding proteins. Overall, our results show that the established library is a useful tool for the discovery of novel bioactive reagents.

  10. High-throughput flow cytometric screening of combinatorial chemistry bead libraries for proteomics and drug discovery

    Science.gov (United States)

    Leary, James F.; Reece, Lisa M.; Yang, Xian-Bin; Gorenstein, David

    2005-04-01

    For proteomics drug discovery applications, combinatorial microbead thioaptamer libraries (one thioaptamer sequence per bead) are being created by split synthesis method, creating a "proteomics library" of protein capture beads which can be analyzed by high-throughput screening methods in this case, flow cytometry and cell sorting. Thioaptamers, oligonucleotides with thiophosphate backbone substitutions, function like antibodies in terms of recognizing specific protein sequences but have a number of advantages over antibody libraries. These proteomics beads can then be analyzed by high-speed flow cytometry and sorted to single-bead level depending on relative fluorescence brightness of fluorescently-labeled proteins, or for a specific protein from all of the molecules of cell subpopulations being analyzed. The thioaptamer sequences on a given bead showing high affinity for that protein can then be sequenced. Alternatively, the protein-capturing beads can be analyzed by MALDI-TOF mass spectrometry for analysis of the bound proteins. The beads can be thought of as equivalent to single-element positions of a proteomics chip arrays but with the advantage of being able to much more rapidly analyze hundreds of millions of possible amino acid sequences/epitopes on the basis of thioaptamer sequence affinities to select single sequences of interest. Additionally, those beads can be manipulated and isolated at the single bead level by high-throughput flow cytometry/cell sorting for subsequent sequencing of the thioaptamer sequences.

  11. Baculovirus superinfection: a probable restriction factor on the surface display of proteins for library screening.

    Science.gov (United States)

    Xu, Xiaodong; Chen, Yuanrong; Zhao, Yu; Liu, Xiaofen; Dong, Beitao; Jones, Ian M; Chen, Hongying

    2013-01-01

    In addition to the expression of recombinant proteins, baculoviruses have been developed as a platform for the display of complex eukaryotic proteins on the surface of virus particles or infected insect cells. Surface display has been used extensively for antigen presentation and targeted gene delivery but is also a candidate for the display of protein libraries for molecular screening. However, although baculovirus gene libraries can be efficiently expressed and displayed on the surface of insect cells, target gene selection is inefficient probably due to super-infection which gives rise to cells expressing more than one protein. In this report baculovirus superinfection of Sf9 cells has been investigated by the use of two recombinant multiple nucleopolyhedrovirus carrying green or red fluorescent proteins under the control of both early and late promoters (vAcBacGFP and vAcBacDsRed). The reporter gene expression was detected 8 hours after the infection of vAcBacGFP and cells in early and late phases of infection could be distinguished by the fluorescence intensity of the expressed protein. Simultaneous infection with vAcBacGFP and vAcBacDsRed viruses each at 0.5 MOI resulted in 80% of infected cells co-expressing the two fluorescent proteins at 48 hours post infection (hpi), and subsequent infection with the two viruses resulted in similar co-infection rate. Most Sf9 cells were re-infectable within the first several hours post infection, but the re-infection rate then decreased to a very low level by 16 hpi. Our data demonstrate that Sf9 cells were easily super-infectable during baculovirus infection, and super-infection could occur simultaneously at the time of the primary infection or subsequently during secondary infection by progeny viruses. The efficiency of super-infection may explain the difficulties of baculovirus display library screening but would benefit the production of complex proteins requiring co-expression of multiple polypeptides.

  12. Systematic hybrid LOH: a new method to reduce false positives and negatives during screening of yeast gene deletion libraries

    DEFF Research Database (Denmark)

    Alvaro, D.; Sunjevaric, I.; Reid, R. J.;

    2006-01-01

    We have developed a new method, systematic hybrid loss of heterozygosity, to facilitate genomic screens utilizing the yeast gene deletion library. Screening is performed using hybrid diploid strains produced through mating the library haploids with strains from a different genetic background......, to minimize the contribution of unpredicted recessive genetic factors present in the individual library strains. We utilize a set of strains where each contains a conditional centromere construct on one of the 16 yeast chromosomes that allows the destabilization and selectable loss of that chromosome. After...... mating a library gene deletion haploid to such a conditional centromere strain, which corresponds to the chromosome carrying the gene deletion, loss of heterozygosity (LOH) at the gene deletion locus can be generated in these otherwise hybrid diploids. The use of hybrid diploid strains permits...

  13. New lipolytic enzymes identified by screening two metagenomic libraries derived from the soil of a winter wheat field

    Directory of Open Access Journals (Sweden)

    Stroobants, A.

    2015-01-01

    Full Text Available Description of the subject. Lipolytic enzymes are widely distributed and fulfil important physiological functions in the microorganisms inhabiting diverse environments. Soils are rich, diversified environments containing microbial communities that remain largely unknown. Objectives. This work aimed to discover new lipolytic enzymes. Method. New enzymes were found by functional screening of two seasonal metagenomic libraries (a winter and a spring library constructed from an agricultural soil. Screens were performed on 2xYT medium supplemented with 3% lipase reagent. Results. Nineteen positive clones were isolated. Analysis of the corresponding inserts led to identifying 23 putative lipolytic enzymes (13 for the winter library and 10 for the spring library displaying between 31% and 62% identity to known enzymes and belonging to seven different families. Conclusions. As enzymes show low identity to known enzymes, the encoded enzymes may display novel biochemical features.

  14. Rapid identification of genes encoding DNA polymerases by function-based screening of metagenomic libraries derived from glacial ice.

    Science.gov (United States)

    Simon, Carola; Herath, Judith; Rockstroh, Stephanie; Daniel, Rolf

    2009-05-01

    Small-insert and large-insert metagenomic libraries were constructed from glacial ice of the Northern Schneeferner, which is located on the Zugspitzplatt in Germany. Subsequently, these libraries were screened for the presence of DNA polymerase-encoding genes by complementation of an Escherichia coli polA mutant. Nine novel genes encoding complete DNA polymerase I proteins or domains typical of these proteins were recovered.

  15. Rapid Identification of Genes Encoding DNA Polymerases by Function-Based Screening of Metagenomic Libraries Derived from Glacial Ice▿

    OpenAIRE

    2009-01-01

    Small-insert and large-insert metagenomic libraries were constructed from glacial ice of the Northern Schneeferner, which is located on the Zugspitzplatt in Germany. Subsequently, these libraries were screened for the presence of DNA polymerase-encoding genes by complementation of an Escherichia coli polA mutant. Nine novel genes encoding complete DNA polymerase I proteins or domains typical of these proteins were recovered.

  16. Development and validation of a high-throughput screen for inhibitors of SARS CoV and its application in screening of a 100,000-compound library.

    Science.gov (United States)

    Severson, William E; Shindo, Nice; Sosa, Mindy; Fletcher, Thomas; White, E Lucile; Ananthan, Subramaniam; Jonsson, Colleen B

    2007-02-01

    The authors have developed a high-throughput screen (HTS) that allows for the identification of potential inhibitors of the severe acute respiratory syndrome coronavirus (SARS CoV) from large compound libraries. The luminescent-based assay measures the inhibition of SARS CoV-induced cytopathic effect (CPE) in Vero E6 cells. The assay was validated in 96-well plates in a BSL3 containment facility. The assay is sensitive and robust, with Z values > 0.6, signal to background (S/B) > 16, and signal to noise (S/N) > 3. The assay was further validated with 2 different diversity sets of compounds against the SARS CoV. The "hit" rate for both libraries was approximately 0.01%. The validated HTS assay was then employed to screen a 100,000-compound library against SARS CoV. The hit rate for the library in a single-dose format was determined to be approximately 0.8%. Screening of the 3 libraries resulted in the identification of several novel compounds that effectively inhibited the CPE of SARS CoV in vitro-compounds which will serve as excellent lead candidates for further evaluation. At a 10-microM concentration, 3 compounds with selective indexes (SI50) of > 53 were discovered.

  17. Application of high-throughput affinity-selection mass spectrometry for screening of chemical compound libraries in lead discovery.

    Science.gov (United States)

    Zehender, Hartmut; Mayr, Lorenz M

    2007-02-01

    High-throughput screening of chemical libraries for compounds that interfere with a particular molecular target is among the most powerful methodologies applied in lead discovery at present. In this review, the authors describe a label-free, homogeneous, affinity-selection-based technology developed at Novartis, termed SpeedScreen, which is compared with similar technologies used for high-throughput screening in the pharmaceutical and biotechnology industries. The focus at present of SpeedScreen is twofold: first, this technology is applied to orphan genomic targets and to those targets that are non-tractable by a functional assay; second, this technology is applied complementary to the well-established traditional methodologies for the screening of molecular targets. In summary, the authors discuss the value of affinity-selection-based high-throughput screening as a complementary technology to the common functional screening platforms and the benefits as well as the limitations of this new technology are outlined.

  18. Users’ Expectation from the User Interface Screen of an Academic Digital Library

    Directory of Open Access Journals (Sweden)

    Akbar Majidi

    2010-09-01

    Full Text Available The present paper investigates the E-learner’s expectations concerning the features incorporated within the user interface screen of an academic digital library. A researcher-made questionnaire was used for the survey. The sample was taken from the E-learners using this technology in Iranian universities. 200 questionnaires were distributed. The data analysis showed a general consensus about the priority of comprehensibility of the terms used in the User Interface Screen (uis as well as the display features and clarity of the navigational functions as the usability criteria for UIS. ANOVA analysis indicated that, with the exception of navigation and guidance functions, there was no significance with respect to three categories of students. In other words, all students had similar expectations and their ICT skill is not a factor influencing the prioritization of these criteria. The results further indicated that except for the browsing page, there is no significant difference between novice, intermediate and advanced students with respect to search screen features.

  19. A novel method to screen genomic libraries that combines genomic immunization with the prime-boost strategy.

    Science.gov (United States)

    Yero, Daniel; Pajón, Rolando; Caballero, Evelin; González, Sonia; Cobas, Karem; Fariñas, Mildrey; Lopez, Yamilé; Acosta, Armando

    2007-08-01

    We employed a prime-boost regimen in combination with the expression library immunization protocol to improve the protective effectiveness of a genomic library used as immunogen. To demonstrate the feasibility of this novel strategy, we used as a prime a serogroup B Neisseria meningitidis random genomic library constructed in a eukaryotic expression vector. Mice immunized with different fractions of this library and boosted with a single dose of meningococcal outer membrane vesicles elicited higher bactericidal antibody titers compared with mice primed with the empty vector. After the boost, passive administration of sera from mice primed with two of these fractions significantly reduced the number of viable bacteria in the blood of infant rats challenged with live N. meningitidis. The method proposed could be applied to the identification of subimmunogenic antigens during vaccine candidate screening by employing expression library immunization.

  20. Construction and screening of a multi-point site- specific mutant library of subtilisin E with a set of oligonucleotides

    Institute of Scientific and Technical Information of China (English)

    肖谷田; 谢毅; 张婕; 孙筱清; 吴小舟; 陈小央; 王启松

    1997-01-01

    A mutant library of subtilisin E containing random combinations of various mutagenized sites wasconstructed by one-round mutagenesis with 15 mutagenic oligonucleotides. Mutants were screened through dot blot hybridization and DNA sequencing. A single-point mutant (Met 222Ala) and a three-point (Asn 76Asp/Asnl09Ser/ I le 205/Cys) mutant gene from the library were expressed. The mutant proteins exhibited conspicuously improved resistance to oxidation and heat treatment, as reported before. The results show that the library is reliable and very useful for protease subtilisin E engineering.

  1. An ontology for pharmaceutical ligands and its application for in silico screening and library design.

    Science.gov (United States)

    Schuffenhauer, Ansgar; Zimmermann, Jürg; Stoop, Ruedi; van der Vyver, Jan-Jan; Lecchini, Steffano; Jacoby, Edgar

    2002-01-01

    Annotation efforts in biosciences have focused in past years mainly on the annotation of genomic sequences. Only very limited effort has been put into annotation schemes for pharmaceutical ligands. Here we propose annotation schemes for the ligands of four major target classes, enzymes, G protein-coupled receptors (GPCRs), nuclear receptors (NRs), and ligand-gated ion channels (LGICs), and outline their usage for in silico screening and combinatorial library design. The proposed schemes cover ligand functionality and hierarchical levels of target classification. The classification schemes are based on those established by the EC, GPCRDB, NuclearDB, and LGICDB. The ligands of the MDL Drug Data Report (MDDR) database serve as a reference data set of known pharmacologically active compounds. All ligands were annotated according to the schemes when attribution was possible based on the activity classification provided by the reference database. The purpose of the ligand-target classification schemes is to allow annotation-based searching of the ligand database. In addition, the biological sequence information of the target is directly linkable to the ligand, hereby allowing sequence similarity-based identification of ligands of next homologous receptors. Ligands of specified levels can easily be retrieved to serve as comprehensive reference sets for cheminformatics-based similarity searches and for design of target class focused compound libraries. Retrospective in silico screening experiments within the MDDR01.1 database, searching for structures binding to dopamine D2, all dopamine receptors and all amine-binding class A GPCRs using known dopamine D2 binding compounds as a reference set, have shown that such reference sets are in particular useful for the identification of ligands binding to receptors closely related to the reference system. The potential for ligand identification drops with increasing phylogenetic distance. The analysis of the focus of a tertiary

  2. Novel ZnO-binding peptides obtained by the screening of a phage display peptide library

    Energy Technology Data Exchange (ETDEWEB)

    Golec, Piotr [Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Laboratory of Molecular Biology (affiliated with the University of Gdansk) (Poland); Karczewska-Golec, Joanna [University of Gdansk and Medical University of Gdansk, Laboratory of Molecular Bacteriology, Intercollegiate Faculty of Biotechnology (Poland); Los, Marcin; Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [University of Gdansk, Department of Molecular Biology (Poland)

    2012-11-15

    Zinc oxide (ZnO) is a semiconductor compound with a potential for wide use in various applications, including biomaterials and biosensors, particularly as nanoparticles (the size range of ZnO nanoparticles is from 2 to 100 nm, with an average of about 35 nm). Here, we report isolation of novel ZnO-binding peptides, by screening of a phage display library. Interestingly, amino acid sequences of the ZnO-binding peptides reported in this paper and those described previously are significantly different. This suggests that there is a high variability in sequences of peptides which can bind particular inorganic molecules, indicating that different approaches may lead to discovery of different peptides of generally the same activity (e.g., binding of ZnO) but having various detailed properties, perhaps crucial under specific conditions of different applications.

  3. A Clinical Drug Library Screen Identifies Tosufloxacin as Being Highly Active against Staphylococcus aureus Persisters

    Directory of Open Access Journals (Sweden)

    Hongxia Niu

    2015-07-01

    Full Text Available To identify effective compounds that are active against Staphylococcus aureus (S. aureus persisters, we screened a clinical drug library consisting of 1524 compounds and identified six drug candidates that had anti-persister activity: tosufloxacin, clinafloxacin, sarafloxacin, doxycycline, thiostrepton, and chlorosalicylanilide. Among them, tosufloxacin had the highest anti-persister activity, which could completely eradicate S. aureus persisters within 2 days in vitro. Clinafloxacin ranked the second with very few persisters surviving the drug exposure. Interestingly, we found that both tosufloxacin and trovafloxacin that had high activity against persisters contained at the N-1 position the 2,4-difluorophenyl group, which is absent in other less active quinolones and may be associated with the high anti-persister activity. Further studies are needed to evaluate tosufloxacin in animal models and to explain its unique activity against bacterial persisters. Our findings may have implications for improved treatment of persistent bacterial infections.

  4. Identification of baicalein as a ferroptosis inhibitor by natural product library screening.

    Science.gov (United States)

    Xie, Yangchun; Song, Xinxin; Sun, Xiaofang; Huang, Jin; Zhong, Meizuo; Lotze, Michael T; Zeh, Herbert J; Kang, Rui; Tang, Daolin

    2016-05-13

    Ferroptosis, a novel form of regulated cell death, is characterized by oxidative injury from iron accumulation and lipid peroxidation. In a natural product library screening for ferroptosis inhibitor, we found that baicalein is a potent inhibitor of erastin-induced ferroptosis in pancreatic cancer cells. Baicalein (also termed 5,6,7-trihydroxyflavone) is a flavonoid originally obtained from the roots of Scutellaria baicalensis and Scutellaria lateriflora. We showed that baicalein exhibits remarkable anti-ferroptosis activity compared with well-known ferroptosis inhibitors such as ferrostatin-1, liproxstatin-1, deferoxamine mesylate, and β-mercaptoethanol. At the biochemistry level, baicalein limits erastin-induced ferrous iron production, glutathione depletion, and lipid peroxidation. At the protein level, baicalein suppresses erastin-mediated degradation of glutathione peroxidase 4, a phospholipid hydroperoxidase that protects cells against membrane lipid peroxidation. Thus, baicalein enhances cellular anti-ferroptosis capacity and could be a potential therapeutic agent for ferroptosis-associated tissue injury.

  5. Understanding Dermatan Sulfate-Heparin Cofactor II Interaction through Virtual Library Screening.

    Science.gov (United States)

    Raghuraman, Arjun; Mosier, Philip D; Desai, Umesh R

    2010-09-09

    Dermatan sulfate, an important member of the glycosaminoglycan family, interacts with heparin cofactor II, a member of the serpin family of proteins, to modulate antithrombotic response. Yet, the nature of this interaction remains poorly understood at a molecular level. We report the genetic algorithm-based combinatorial virtual library screening study of a natural, high-affinity dermatan sulfate hexasaccharide with heparin cofactor II. Of the 192 topologies possible for the hexasaccharide, only 16 satisfied the "high-specificity" criteria used in computational study. Of these, 13 topologies were predicted to bind in the heparin-binding site of heparin cofactor II at a ∼60° angle to helix D, a novel binding mode. This new binding geometry satisfies all known solution and mutagenesis data and supports thrombin ternary complexation through a template mechanism. The study is expected to facilitate the design of allosteric agonists of heparin cofactor II as antithrombotic agents.

  6. Function-Based Metagenomic Library Screening and Heterologous Expression Strategy for Genes Encoding Phosphatase Activity.

    Science.gov (United States)

    Villamizar, Genis A Castillo; Nacke, Heiko; Daniel, Rolf

    2017-01-01

    The release of phosphate from inorganic and organic phosphorus compounds can be mediated enzymatically. Phosphate-releasing enzymes, comprising acid and alkaline phosphatases, are recognized as useful biocatalysts in applications such as plant and animal nutrition, bioremediation and diagnostic analysis. Metagenomic approaches provide access to novel phosphatase-encoding genes. Here, we describe a function-based screening approach for rapid identification of genes conferring phosphatase activity from small-insert and large-insert metagenomic libraries derived from various environments. This approach bears the potential for discovery of entirely novel phosphatase families or subfamilies and members of known enzyme classes hydrolyzing phosphomonoester bonds such as phytases. In addition, we provide a strategy for efficient heterologous phosphatase gene expression.

  7. The interactome of soybean GmWRKY53 using yeast 2-hybrid library screening to saturation.

    Science.gov (United States)

    Tripathi, Prateek; Rabara, Roel C; Choudhary, Mani Kant; Miller, Marissa A; Huang, Ying-Sheng; Shen, Qingxi J; Blachon, Stéphanie; Rushton, Paul J

    2015-01-01

    Soybean GmWRKY53 functions in both biotic and abiotic stress signaling. Using GmWRKY53 as a bait yeast 2-hybrid library screening to saturation isolated multiple independent fragments for many interacting proteins, enabling delineation of minimal interacting domains and computation of a confidence score. Multiple independent clones coding for the LATE ELONGATED HYPOCOTYL clock protein GmLCL2 (MYB114) were isolated and the binding site for GmWRKY53 was mapped to 90 amino acids separate from the MYB domain. This suggests a direct input from the clock on GmWRKY53 activity. The GmWRKY53-interacting proteins also included 3 water stress-inducible AP2/ERF transcription factors. One of these (Glyma03g26310) is one of the most strongly water stress induced genes in soybean roots, suggesting that GmWRKY53/ERF complexes regulate water stress responses.

  8. Construction of Full-length cDNA Library for Antler Tip Tissue of Sika Deer%东北梅花鹿鹿茸尖端组织全长cDNA文库的构建

    Institute of Scientific and Technical Information of China (English)

    郝丽; 李和平; 严厉

    2009-01-01

    为克隆出与鹿茸生长发育相关基因的全长序列,采用SMART技术构建了东北梅花鹿鹿茸尖端组织的全长cDNA文库.用SV Total RNA Isolation System试剂盒提取总RNA,以逆转录酶PowerScriptTM 反转录合成第一链cDNA,然后通过LD-PCR合成并扩增ds cDNA.扩增产物经纯化、SfiⅠ酶切、过CHROMA SPIN-400柱去除小片段后,连接到SfiⅠ消化过的pDNR-LIB质粒载体中,最后用电转化法将重组质粒转化到E. coli DH5α内得到原始文库.经测定,构建的原始文库约含有2.56×10~6个重组子,插入片段多在0.5~2kb之间,平均插入片段长度约1.1kb,重组效率接近100%.结果表明,东北梅花鹿鹿茸尖端组织的全长cDNA文库已构建成功.%A study was conducted to construct full-length cDNA library from antler tip tissues of Sika Deer (Cenna nippon hortu-lonun) by SMART technique in order to clone new special genes for development of antler. The total RNA was extracted u-sing SV Total RNA Isolation System. Single-stranded cDNA was synthesized using PowerScripiTM reverse transcriptase,and double-stranded cDNA was synthesized and amplified by long-distance PCR. The PCR products were digested by pro-teinase K and purified. After digestion with Sfi I and size fractionation using CHROMA SPIN -400TM Columns, SMART cDNA was ligated to the Sfi I-digested, dephosphorylated pDNR-LIB vector, and the ligation mixture was transformed into E. call DH5a by electroporation. The primary cDNA library contained 2.56×10~6 independent clones with DNA inserts of 0.5~2. 0 kb, the average size of inserted cDNAs was 1.1 kb, and the recombination percentage was about 100%. Results showed that the full-length cDNA library from antler tip tissues of Sika Deer was successfully constructed.

  9. A new set of ESTs and cDNA clones from full-length and normalized libraries for gene discovery and functional characterization in citrus

    OpenAIRE

    Alamar Santiago; Arribas Raquel; Forment Javier; Alonso-Cantabrana Hugo; Marques M Carmen; Conejero Vicente; Perez-Amador Miguel A

    2009-01-01

    Abstract Background Interpretation of ever-increasing raw sequence information generated by modern genome sequencing technologies faces multiple challenges, such as gene function analysis and genome annotation. Indeed, nearly 40% of genes in plants encode proteins of unknown function. Functional characterization of these genes is one of the main challenges in modern biology. In this regard, the availability of full-length cDNA clones may fill in the gap created between sequence information an...

  10. Cloning of Bt cry Genes by Rapid Screening of DNA Libraries with PCR-RFLP

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhong-yi; WU Xian; ZHANG Jie; SONG Fu-ping; GUAN Yu; HUANG Da-fang

    2003-01-01

    Bacillus thuringiensis (Bt) strain C002 contains crylAa, cry2Ab, cry1Ca insecticidal crystal genes and an unkown gene cryX, among which crylCa is located in a 6 -9 kb EcoR Ⅰ fragment of the chromosomal DNA. The total DNA and the plasmids DNA libraries of C002 were constructed in Bt-E. coli shuttle plasmid pHT315 by inserting 6 - 9 kb chromosomal and plasmid DNA fragments prepared respectively with EcoR Ⅰ complete and Sau3A Ⅰ partial digestion. On the basis of every 50 transformants pooled together from 5 - 10 tubes, the pools containing about 2 000 transformants from the plasmids DNA library and 400 transformants from the total DNA library were rapidly screened by PCR-RFLP. Clones containing crylAa, cryX, crylCa, and cry2Ab were isolated and named as pHT-1Aa, pHT-X, pHT-1Ca and pHT-2Ab respectively. Restriction analysis indicated that pHT-1Aa, pHT-1Ca and pHT-2Ab had the typical physical map of the homologous cry genes. Furthermore, each plasmid was transferred into Bt acrystalliferous strain cryB- by eletroporation. SDS-PAGE result showed that transformant of pHT-1Ca expressed 130 kDa protein and bioassay result proved its high toxicity against Spodotera exigua 1st instar larvae with 100% corrected motality.

  11. A Barcoding Strategy Enabling Higher-Throughput Library Screening by Microscopy.

    Science.gov (United States)

    Chen, Robert; Rishi, Harneet S; Potapov, Vladimir; Yamada, Masaki R; Yeh, Vincent J; Chow, Thomas; Cheung, Celia L; Jones, Austin T; Johnson, Terry D; Keating, Amy E; DeLoache, William C; Dueber, John E

    2015-11-20

    Dramatic progress has been made in the design and build phases of the design-build-test cycle for engineering cells. However, the test phase usually limits throughput, as many outputs of interest are not amenable to rapid analytical measurements. For example, phenotypes such as motility, morphology, and subcellular localization can be readily measured by microscopy, but analysis of these phenotypes is notoriously slow. To increase throughput, we developed microscopy-readable barcodes (MiCodes) composed of fluorescent proteins targeted to discernible organelles. In this system, a unique barcode can be genetically linked to each library member, making possible the parallel analysis of phenotypes of interest via microscopy. As a first demonstration, we MiCoded a set of synthetic coiled-coil leucine zipper proteins to allow an 8 × 8 matrix to be tested for specific interactions in micrographs consisting of mixed populations of cells. A novel microscopy-readable two-hybrid fluorescence localization assay for probing candidate interactions in the cytosol was also developed using a bait protein targeted to the peroxisome and a prey protein tagged with a fluorescent protein. This work introduces a generalizable, scalable platform for making microscopy amenable to higher-throughput library screening experiments, thereby coupling the power of imaging with the utility of combinatorial search paradigms.

  12. Applications of a catch and release electrospray ionization mass spectrometry assay for carbohydrate library screening.

    Science.gov (United States)

    El-Hawiet, Amr; Shoemaker, Glen K; Daneshfar, Rambod; Kitova, Elena N; Klassen, John S

    2012-01-03

    Applications of a catch and release electrospray ionization mass spectrometry (CaR-ESI-MS) assay for screening carbohydrate libraries against target proteins are described. Direct ESI-MS measurements were performed on solutions containing a target protein (a single chain antibody, an antigen binding fragment, or a fragment of a bacterial toxin) and a library of carbohydrates containing multiple specific ligands with affinities in the 10(3) to 10(6) M(-1) range. Ligands with moderate affinity (10(4) to 10(6) M(-1)) were successfully detected from mixtures containing >200 carbohydrates (at concentrations as low as 0.25 μM each). Additionally, the absolute affinities were estimated from the abundance of free and ligand-bound protein ions determined from the ESI mass spectrum. Multiple low affinity ligands (~10(3) M(-1)) were successfully detected in mixtures containing >20 carbohydrates (at concentrations of ~10 μM each). However, identification of specific interactions required the use of the reference protein method to correct the mass spectrum for the occurrence of nonspecific carbohydrate-protein binding during the ESI process. The release of the carbohydrate ligands, as ions, was successfully demonstrated using collision-induced dissociation performed on the deprotonated ions of the protein-carbohydrate complexes. The use of ion mobility separation, performed on deprotonated carbohydrate ions following their release from the complex, allowed for the positive identification of isomeric ligands.

  13. Study on the Mitochondrial Genome of Sea Island Cotton (Gossypium barbadense) by BAC Library Screening

    Institute of Scientific and Technical Information of China (English)

    SU Ai-guo; LI Shuang-shuang; LIU Guo-zheng; LEI Bin-bin; KANG Ding-ming; LI Zhao-hu; MA Zhi-ying; HUA Jin-ping

    2014-01-01

    The plant mitochondrial genome displays complex features, particularly in terms of cytoplasmic male sterility (CMS). Therefore, research on the cotton mitochondrial genome may provide important information for analyzing genome evolution and exploring the molecular mechanism of CMS. In this paper, we present a preliminary study on the mitochondrial genome of sea island cotton (Gossypium barbadense) based on positive clones from the bacterial artiifcial chromosome (BAC) library. Thirty-ifve primers designed with the conserved sequences of functional genes and exons of mitochondria were used to screen positive clones in the genome library of the sea island cotton variety called Pima 90-53. Ten BAC clones were obtained and veriifed for further study. A contig was obtained based on six overlapping clones and subsequently laid out primarily on the mitochondrial genome. One BAC clone, clone 6 harbored with the inserter of approximate 115 kb mtDNA sequence, in which more than 10 primers fragments could be ampliifed, was sequenced and assembled using the Solexa strategy. Fifteen mitochondrial functional genes were revealed in clone 6 by gene annotation. The characteristics of the syntenic gene/exon of the sequences and RNA editing were preliminarily predicted.

  14. Employing libraries of zinc finger artificial transcription factors to screen for homologous recombination mutants in Arabidopsis.

    Science.gov (United States)

    Lindhout, Beatrice I; Pinas, Johan E; Hooykaas, Paul J J; van der Zaal, Bert J

    2006-11-01

    A library of genes for zinc finger artificial transcription factors (ZF-ATF) was generated by fusion of DNA sequences encoding three-finger Cys(2)His(2) ZF domains to the VP16 activation domain under the control of the promoter of the ribosomal protein gene RPS5A from Arabidopsis thaliana. After introduction of this library into an Arabidopsis homologous recombination (HR) indicator line, we selected primary transformants exhibiting multiple somatic recombination events. After PCR-mediated rescue of ZF sequences, reconstituted ZF-ATFs were re-introduced in the target line. In this manner, a ZF-ATF was identified that led to a 200-1000-fold increase in somatic HR (replicated in an independent second target line). A mutant plant line expressing the HR-inducing ZF-ATF exhibited increased resistance to the DNA-damaging agent bleomycin and was more sensitive to methyl methanesulfonate (MMS), a combination of traits not described previously. Our results demonstrate that the use of ZF-ATF pools is highly rewarding when screening for novel dominant phenotypes in Arabidopsis.

  15. Methods for transforming and expression screening of filamentous fungal cells with a DNA library

    Energy Technology Data Exchange (ETDEWEB)

    Teter, Sarah; Lamsa, Michael; Cherry, Joel; Ward, Connie

    2015-06-02

    The present invention relates to methods for expression screening of filamentous fungal transformants, comprising: (a) isolating single colony transformants of a DNA library introduced into E. coli; (b) preparing DNA from each of the single colony E. coli transformants; (c) introducing a sample of each of the DNA preparations of step (b) into separate suspensions of protoplasts of a filamentous fungus to obtain transformants thereof, wherein each transformant contains one or more copies of an individual polynucleotide from the DNA library; (d) growing the individual filamentous fungal transformants of step (c) on selective growth medium, thereby permitting growth of the filamentous fungal transformants, while suppressing growth of untransformed filamentous fungi; and (e) measuring activity or a property of each polypeptide encoded by the individual polynucleotides. The present invention also relates to isolated polynucleotides encoding polypeptides of interest obtained by such methods, to nucleic acid constructs, expression vectors, and recombinant host cells comprising the isolated polynucleotides, and to methods of producing the polypeptides encoded by the isolated polynucleotides.

  16. 多头带绦虫脑多头蚴cDNA表达文库的构建及初步分析%Construction and Preliminary Analysis of cDNA Expression Library of Coenurus cerebralis of Taenia multiceps

    Institute of Scientific and Technical Information of China (English)

    李文卉; 王建魁; 盖文燕; 姚菊霞; 曲自刚; 贾万忠; 罗建勋; Radu Blaga; 付宝权

    2011-01-01

    从甘肃景泰羊源脑多头蚴原头节提取总RNA,以Oligo(dT)纤维素柱纯化mRNA,利用Lambda ZAP II XR文库构建试剂盒构建了脑多头蚴cDNA表达文库.从构建的原始文库随机挑选单个噬菌斑进行PCR,确定文库重组率和插入外源基因片段大小,鉴定文库质量.结果表明脑多头蚴cDNA表达文库的原始库容量为1.0×106 pfu,扩增后文库滴度为1.6×109 pfu/mL.随机挑选的165个噬菌斑克隆中,0.25 kb以上的克隆155个,重组率为93.9%,对其中0.5 kb以上的115个克隆测序共获得104个表达序列标签(EST),分析后得到96个单一EST序列(Unique EST),其中20个EST与绦虫基因有同源性,38个EST与吸虫基因有同源性,4个EST与线虫基因有同源性,17个EST与其他物种有同源性,其余17个EST没有同源基因.这些EST编码的氨基酸序列有多头带绦虫六钩蚴Tm16抗原、猪带绦虫副肌球蛋白、猪带绦虫免疫原蛋白Ts76等绦虫抗原的同源蛋白以及烯醇化酶等一些酶类、热休克蛋白、肌动蛋白、核糖体蛋白等同源蛋白.%Total RNA was extracted from protoscolex of Coenurus cerebralis from naturally infected sheep of Jingtai Co. ,Gansu, and mRNA was isolated with Oligo ( dT) cellulose column. The Coenurus cerebralis cDNA expression library was constructed with Lambda ZAP Ⅱ XR vector. The randomly picked clones from primary cDNA library was amplified with PCR to detect the recombinant rate of cDNA lihrary and size of DNA inserts. The results indicated the size of the preliminary cDNA library was 1. 0 × 106 pfu with the titer of the amplified cDNA library of 1. 6 x 109 pfu/mL. From randomly picked 165 clones, 155 were with the size more than 250 bp and the recombinant rate was 93. 9% . Furthermore , 115 clones sized more than 500 bp were sequenced and 104 expressed sequence tags (ESTs) were obtained. After analysis 96 unique ESTs were obtained, of which 20 were homologous with cestode, 38 were homologous with

  17. Baculovirus superinfection: a probable restriction factor on the surface display of proteins for library screening.

    Directory of Open Access Journals (Sweden)

    Xiaodong Xu

    Full Text Available In addition to the expression of recombinant proteins, baculoviruses have been developed as a platform for the display of complex eukaryotic proteins on the surface of virus particles or infected insect cells. Surface display has been used extensively for antigen presentation and targeted gene delivery but is also a candidate for the display of protein libraries for molecular screening. However, although baculovirus gene libraries can be efficiently expressed and displayed on the surface of insect cells, target gene selection is inefficient probably due to super-infection which gives rise to cells expressing more than one protein. In this report baculovirus superinfection of Sf9 cells has been investigated by the use of two recombinant multiple nucleopolyhedrovirus carrying green or red fluorescent proteins under the control of both early and late promoters (vAcBacGFP and vAcBacDsRed. The reporter gene expression was detected 8 hours after the infection of vAcBacGFP and cells in early and late phases of infection could be distinguished by the fluorescence intensity of the expressed protein. Simultaneous infection with vAcBacGFP and vAcBacDsRed viruses each at 0.5 MOI resulted in 80% of infected cells co-expressing the two fluorescent proteins at 48 hours post infection (hpi, and subsequent infection with the two viruses resulted in similar co-infection rate. Most Sf9 cells were re-infectable within the first several hours post infection, but the re-infection rate then decreased to a very low level by 16 hpi. Our data demonstrate that Sf9 cells were easily super-infectable during baculovirus infection, and super-infection could occur simultaneously at the time of the primary infection or subsequently during secondary infection by progeny viruses. The efficiency of super-infection may explain the difficulties of baculovirus display library screening but would benefit the production of complex proteins requiring co-expression of multiple

  18. Solid-phase synthesis and screening of N-acylated polyamine (NAPA) combinatorial libraries for protein binding.

    Science.gov (United States)

    Iera, Jaclyn A; Jenkins, Lisa M Miller; Kajiyama, Hiroshi; Kopp, Jeffrey B; Appella, Daniel H

    2010-11-15

    Inhibitors for protein-protein interactions are challenging to design, in part due to the unique and complex architectures of each protein's interaction domain. Most approaches to develop inhibitors for these interactions rely on rational design, which requires prior structural knowledge of the target and its ligands. In the absence of structural information, a combinatorial approach may be the best alternative to finding inhibitors of a protein-protein interaction. Current chemical libraries, however, consist mostly of molecules designed to inhibit enzymes. In this manuscript, we report the synthesis and screening of a library based on an N-acylated polyamine (NAPA) scaffold that we designed to have specific molecular features necessary to inhibit protein-protein interactions. Screens of the library identified a member with favorable binding properties to the HIV viral protein R (Vpr), a regulatory protein from HIV, that is involved in numerous interactions with other proteins critical for viral replication.

  19. Modulators of prostate cancer cell proliferation and viability identified by short-hairpin RNA library screening.

    Directory of Open Access Journals (Sweden)

    Kimberly Brown Dahlman

    Full Text Available There is significant need to identify novel prostate cancer drug targets because current hormone therapies eventually fail, leading to a drug-resistant and fatal disease termed castration-resistant prostate cancer. To functionally identify genes that, when silenced, decrease prostate cancer cell proliferation or induce cell death in combination with antiandrogens, we employed an RNA interference-based short hairpin RNA barcode screen in LNCaP human prostate cancer cells. We identified and validated four candidate genes (AKT1, PSMC1, STRADA, and TTK that impaired growth when silenced in androgen receptor positive prostate cancer cells and enhanced the antiproliferative effects of antiandrogens. Inhibition of AKT with a pharmacologic inhibitor also induced apoptosis when combined with antiandrogens, consistent with recent evidence for PI3K and AR pathway crosstalk in prostate cancer cells. Recovery of hairpins targeting a known prostate cancer pathway validates the utility of shRNA library screening in prostate cancer as a broad strategy to identify new candidate drug targets.

  20. Modulators of prostate cancer cell proliferation and viability identified by short-hairpin RNA library screening.

    Science.gov (United States)

    Dahlman, Kimberly Brown; Parker, Joel S; Shamu, Tambudzai; Hieronymus, Haley; Chapinski, Caren; Carver, Brett; Chang, Kenneth; Hannon, Gregory J; Sawyers, Charles L

    2012-01-01

    There is significant need to identify novel prostate cancer drug targets because current hormone therapies eventually fail, leading to a drug-resistant and fatal disease termed castration-resistant prostate cancer. To functionally identify genes that, when silenced, decrease prostate cancer cell proliferation or induce cell death in combination with antiandrogens, we employed an RNA interference-based short hairpin RNA barcode screen in LNCaP human prostate cancer cells. We identified and validated four candidate genes (AKT1, PSMC1, STRADA, and TTK) that impaired growth when silenced in androgen receptor positive prostate cancer cells and enhanced the antiproliferative effects of antiandrogens. Inhibition of AKT with a pharmacologic inhibitor also induced apoptosis when combined with antiandrogens, consistent with recent evidence for PI3K and AR pathway crosstalk in prostate cancer cells. Recovery of hairpins targeting a known prostate cancer pathway validates the utility of shRNA library screening in prostate cancer as a broad strategy to identify new candidate drug targets.

  1. Chemical library screening using a SPR-based inhibition in solution assay: simulations and experimental validation.

    Science.gov (United States)

    Choulier, Laurence; Nominé, Yves; Zeder-Lutz, Gabrielle; Charbonnier, Sebastian; Didier, Bruno; Jung, Marie-Louise; Altschuh, Danièle

    2013-09-17

    We have developed a surface plasmon resonance (SPR)-based inhibition in solution assay (ISA) to search for inhibitors of the medium affinity (KD = 0.8 μM) interaction between an E6-derived peptide (E6peptide) immobilized on the sensor and a PDZ domain (MAGI-1 PDZ1) in the mobile phase. DZ domains are widespread protein-protein interaction modules that recognize the C-terminus of various partners. Simulations indicated that relatively low compound concentrations (10 μM) and limited peptide densities (Rmax < 200 resonance units) should allow the detection of inhibitors with a target affinity close to 100 μM, which was then demonstrated experimentally. ISA screening, carried out on the Prestwick Chemical Library® (1120 compounds), identified 36 compounds that inhibited the interaction by more than 5%. Concentration-dependent ISA, carried out on a subset of 19 potential inhibitors, indicated that 13 of these indeed affected the interaction between MAGI-1 PDZ1 and the E6peptide. No effect was observed for 84 compounds randomly chosen among noninhibitors. One of the four best inhibitors was a peptide binder, and three were PDZ binders with KD in the 10-50 μM range. We propose that a medium (μM) affinity between the target and surface-bound partner is optimal for SPR-based ISA screening.

  2. Discovery of two new inhibitors of Botrytis cinerea chitin synthase by a chemical library screening.

    Science.gov (United States)

    Magellan, Hervé; Boccara, Martine; Drujon, Thierry; Soulié, Marie-Christine; Guillou, Catherine; Dubois, Joëlle; Becker, Hubert F

    2013-09-01

    Chitin synthases polymerize UDP-GlcNAC to form chitin polymer, a key component of fungal cell wall biosynthesis. Furthermore, chitin synthases are desirable targets for fungicides since chitin is absent in plants and mammals. Two potent Botrytis cinerea chitin synthase inhibitors, 2,3,5-tri-O-benzyl-d-ribose (compound 1) and a 2,5-functionalized imidazole (compound 2) were identified by screening a chemical library. We adapted the wheat germ agglutinin (WGA) test for chitin synthase activity detection to allow miniaturization and robotization of the screen. Both identified compounds inhibited chitin synthases in vitro with IC50 values of 1.8 and 10μM, respectively. Compounds 1 and 2 were evaluated for their antifungal activity and were found to be active against B. cinerea BD90 strain with MIC values of 190 and 100μM, respectively. Finally, we discovered that both compounds confer resistance to plant leaves against the attack of the fungus by reducing the propagation of lesions by 37% and 23%, respectively. Based on the inhibitory properties found in different assays, compounds 1 and 2 can be considered as antifungal hit inhibitors of chitin synthase, allowing further optimization of their pharmacological profile to improve their antifungal properties.

  3. A polystyrene binding target-unrelated peptide isolated in the screening of phage display library.

    Science.gov (United States)

    Bakhshinejad, Babak; Sadeghizadeh, Majid

    2016-11-01

    Phage display is a powerful methodology for the identification of peptide ligands binding to any desired target. However, the selection of target-unrelated peptides (TUPs) appears as a huge problem in the screening of phage display libraries through biopanning. The phage-displayed peptide TLHPAAD has been isolated both in our laboratory and by another reserach group on completely different screening targets prompting us to hypothesize that it may be a potential TUP. In the current study, we analyzed the binding characteristics and propagation rate of phage clone displaying TLHPAAD peptide (SW-TUP clone). The results of ELISA experiment and phage recovery assay provided strong support for the notion that SW-TUP phage binds to polystyrene with a significantly higher affinity than control phage clones. Furthermore, this polystyrene binding was demonstrated to occur in a concentration- and pH-dependent mode. Characterization of the propagation profile of phage clones within a specified time course revealed no statistically significant difference between the amplification rate of SW-TUP and control phages. Our findings lead us to the conclusion that SW-TUP phage clone with the displayed peptide TLHPAAD is not a true target binder and its selection in biopanning experiments results from its bidning affinity to the polystyrene surface of the solid phase.

  4. Screening Peptide Inhibitors Using Phage Peptide Library with Isocitrate Lyase in Mycobacterium tuberculosis as Target

    Institute of Scientific and Technical Information of China (English)

    YIN Yu-he; NIU Xue; SUN Bo; TENG Guo-sheng; ZHAO Yun-hui; WU Cong-mei

    2011-01-01

    When devoured by macrophages,Mycobacterium tuberculosis remains persistent in macrophages and gains energy through the glyoxylate bypass to maintain its long-term existence in host cells.Therefore it is possible to stop persistent infections by interdicting the glyoxylate bypass in which the isocitrate lyase(ICL) is the key rate-limiting enzyme and a persistence factor.ICL is the target of anti-TB(TB:tubercular) drugs,which could screen ICL out and effectively inhibit the activity of ICL in Mycobacterium tuberculosis,and because of this,anti-TB drugs can be used to kill persistent Mycobacterium tuberculosis.In this study,the ICL gene of the Mycobacterium tuberculosis H37Rv was cloned successfully and recombinant protein with bioactivity was obtained through the enzyme characteristic appraisal.The specific activity of the recombined ICL is 24 μmol·mg-1 -min-1.The recombined ICL protein was used as the target,and phages which can specifically combine to ICL were screened in the phage 7 peptide library.According to the results of the ELISA and DNA sequence detection,eventually three 7-peptide chains were synthesized.Then the peptide chains were reacted with ICL,respectively,to detect their inhibitory effects on ICL.The results show that all the three 7-peptide chains possessed varying inhibitory effects on the activity of ICL.This study provided lead compounds for the research and development of new peptide anti-TB drugs.

  5. Discovery of Inhibitors of Trypanosoma brucei by Phenotypic Screening of a Focused Protein Kinase Library.

    Science.gov (United States)

    Woodland, Andrew; Thompson, Stephen; Cleghorn, Laura A T; Norcross, Neil; De Rycker, Manu; Grimaldi, Raffaella; Hallyburton, Irene; Rao, Bhavya; Norval, Suzanne; Stojanovski, Laste; Brun, Reto; Kaiser, Marcel; Frearson, Julie A; Gray, David W; Wyatt, Paul G; Read, Kevin D; Gilbert, Ian H

    2015-11-01

    A screen of a focused kinase inhibitor library against Trypanosoma brucei rhodesiense led to the identification of seven series, totaling 121 compounds, which showed >50 % inhibition at 5 μm. Screening of these hits in a T. b. brucei proliferation assay highlighted three compounds with a 1H-imidazo[4,5-b]pyrazin-2(3H)-one scaffold that showed sub-micromolar activity and excellent selectivity against the MRC5 cell line. Subsequent rounds of optimisation led to the identification of compounds that exhibited good in vitro drug metabolism and pharmacokinetics (DMPK) properties, although in general this series suffered from poor solubility. A scaffold-hopping exercise led to the identification of a 1H-pyrazolo[3,4-b]pyridine scaffold, which retained potency. A number of examples were assessed in a T. b. brucei growth assay, which could differentiate static and cidal action. Compounds from the 1H-imidazo[4,5-b]pyrazin-2(3H)-one series were found to be either static or growth-slowing and not cidal. Compounds with the 1H-pyrazolo[3,4-b]pyridine scaffold were found to be cidal and showed an unusual biphasic nature in this assay, suggesting they act by at least two mechanisms.

  6. Construction of a full-length cDNA Library from Chinese oak silkworm pupa and identification of a KK-42-binding protein gene in relation to pupa-diapause termination

    Directory of Open Access Journals (Sweden)

    Yu-Ping Li, Run-Xi Xia, Huan Wang, Xi-Sheng Li, Yan-Qun Liu, Zhao-Jun Wei, Cheng Lu, Zhong-Huai Xiang

    2009-01-01

    Full Text Available In this study we successfully constructed a full-length cDNA library from Chinese oak silkworm, Antheraea pernyi, the most well-known wild silkworm used for silk production and insect food. Total RNA was extracted from a single fresh female pupa at the diapause stage. The titer of the library was 5 × 105 cfu/ml and the proportion of recombinant clones was approximately 95%. Expressed sequence tag (EST analysis was used to characterize the library. A total of 175 clustered ESTs consisting of 24 contigs and 151 singlets were generated from 250 effective sequences. Of the 175 unigenes, 97 (55.4% were known genes but only five from A. pernyi, 37 (21.2% were known ESTs without function annotation, and 41 (23.4% were novel ESTs. By EST sequencing, a gene coding KK-42-binding protein in A. pernyi (named as ApKK42-BP; GenBank accession no. FJ744151 was identified and characterized. Protein sequence analysis showed that ApKK42-BP was not a membrane protein but an extracellular protein with a signal peptide at position 1-18, and contained two putative conserved domains, abhydro_lipase and abhydrolase_1, suggesting it may be a member of lipase superfamily. Expression analysis based on number of ESTs showed that ApKK42-BP was an abundant gene in the period of diapause stage, suggesting it may also be involved in pupa-diapause termination.

  7. Screening of Proteins Interacting with Nonstructural 1 Protein of H5N1 Avian Influenza Virus from T7-phage Display Library

    Institute of Scientific and Technical Information of China (English)

    ZHU Chun-yu; WU Jian-guo; LIU Hong-sheng; SUN Ting-ting; ZHAO Jian; WANG Ning; ZHENG Fang-liang; AI Hai-xin; ZHU Jun-feng; WANG Xiao-ying; ZHU Ying

    2012-01-01

    Avian influenza virus(AIV) nonstructural 1(NS1) gene was amplified by real-time polymerse chain reaction(RT-PCR) and inserted into pET28a,then transformed into E.coli BL21(DE3) competent cell.With the induction of isopropyl-β-D-thiogalactoside(IPTG) and the purification of Ni-NTA column,we finally obtained purified NS1 protein.T7-phage display system was used to screen the proteins that interacted with NS1 from lung cell cDNA library.The selected positive clones were identified by DNA sequencing and analyzed by BLAST program in GeneBank.Two proteins were obtained as NS 1 binding proteins,Homo sapiens nucleolar and coiled-body phosphoprotein 1(NOLC1) and Homo sapiens similar to colon cancer-associated antigen.By co-immunoprecipitation and other methods,Homo sapiens NOLC1 was found to interact with the NS1 protein,the results would provide the basis for further studying biological function of NS1 protein.

  8. Peptide ligands for pro-survival protein Bfl-1 from computationally guided library screening.

    Science.gov (United States)

    Dutta, Sanjib; Chen, T Scott; Keating, Amy E

    2013-04-19

    Pro-survival members of the Bcl-2 protein family inhibit cell death by binding short helical BH3 motifs in pro-apoptotic proteins. Mammalian pro-survival proteins Bcl-x(L), Bcl-2, Bcl-w, Mcl-1, and Bfl-1 bind with varying affinities and specificities to native BH3 motifs, engineered peptides, and small molecules. Biophysical studies have determined interaction patterns for these proteins, particularly for the most-studied family members Bcl-x(L) and Mcl-1. Bfl-1 is a pro-survival protein implicated in preventing apoptosis in leukemia, lymphoma, and melanoma. Although Bfl-1 is a promising therapeutic target, relatively little is known about its binding preferences. We explored the binding of Bfl-1 to BH3-like peptides by screening a peptide library that was designed to sample a high degree of relevant sequence diversity. Screening using yeast-surface display led to several novel high-affinity Bfl-1 binders and to thousands of putative binders identified through deep sequencing. Further screening for specificity led to identification of a peptide that bound to Bfl-1 with K(d) < 1 nM and very slow dissociation from Bfl-1 compared to other pro-survival Bcl-2 family members. A point mutation in this sequence gave a peptide with ~50 nM affinity for Bfl-1 that was selective for Bfl-1 in equilibrium binding assays. Analysis of engineered Bfl-1 binders deepens our understanding of how the binding profiles of pro-survival proteins differ and may guide the development of targeted Bfl-1 inhibitors.

  9. Identification and cloning of the cDNA of a Rb-associated protein RAP140a

    Institute of Scientific and Technical Information of China (English)

    李权; 闻宏; 敖世洲

    2000-01-01

    Rb exerts important physiological functions in cell-cycle control, gene expression, cell differentiation, apoptosis, development and tumorigenesis by interacting with many cellular proteins. Using human partial Rb as bait, we screened a human fetal brain cDNA library through yeast two-hybrid system and obtained six novel cDNA fragments. Among them, one cDNA fragment corresponds to two different transcripts, 7 kb and 9 kb in Northern blot analysis. These two transcripts showed uniform distribution in various human tissues. We cloned the full-length cDNA of a 7.2 kb transcript through three times PCR amplifications. It was named RAP140a and predicted to encode a 1 233 amino acids hydrophilic protein. RAP140a was mapped to chromosome 3p13-p14.1. RAP140a may be functionally related to the intracellular translocation of Rb or other proteins.

  10. Identification and cloning of the cDNA of a Rb-associated protein RAP140a

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Rb exerts important physiological functions in cell-cycle control, gene expression, cell differentiation, apoptosis, development and tumorigenesis by interacting with many cellular proteins. Using human partial Rb as bait, we screened a human fetal brain cDNA library through yeast two-hybrid system and obtained six novel cDNA fragments. Among them, one cDNA fragment corre-sponds to two different transcripts, 7 kb and 9 kb in Northern blot analysis. These two transcripts showed uniform distribution in various human tissues. We cloned the full-length cDNA of a 7.2 kb transcript through three times PCR amplifications. It was named RAP140a and predicted to encode a 1 233 amino acids hydrophilic protein. RAP140a was mapped to chromosome 3p13-p14.1. RAP140a may be functionally related to the intracellular translocation of Rb or other proteins.

  11. Development of peritoneal tumor-targeting vector by in vivo screening with a random peptide-displaying adenovirus library.

    Directory of Open Access Journals (Sweden)

    Takeshi Nishimoto

    Full Text Available The targeting of gene transfer at the cell-entry level is one of the most attractive challenges in vector development. However, attempts to redirect adenovirus vectors to alternative receptors by engineering the capsid-coding region have shown limited success, because the proper targeting ligands on the cells of interest are generally unknown. To overcome this limitation, we have constructed a random peptide library displayed on the adenoviral fiber knob, and have successfully selected targeted vectors by screening the library on cancer cell lines in vitro. The infection of targeted vectors was considered to be mediated by specific receptors on target cells. However, the expression levels and kinds of cell surface receptors may be substantially different between in vitro culture and in vivo tumor tissue. Here, we screened the peptide display-adenovirus library in the peritoneal dissemination model of AsPC-1 pancreatic cancer cells. The vector displaying a selected peptide (PFWSGAV showed higher infectivity in the AsPC-1 peritoneal tumors but not in organs and other peritoneal tumors as compared with a non-targeted vector. Furthermore, the infectivity of the PFWSGAV-displaying vector for AsPC-1 peritoneal tumors was significantly higher than that of a vector displaying a peptide selected by in vitro screening, indicating the usefulness of in vivo screening in exploring the targeting vectors. This vector-screening system can facilitate the development of targeted adenovirus vectors for a variety of applications in medicine.

  12. Construction and analysis of suppression subtractive cDNA libraries of continuous monoculture Rehmannia glutinosa%连作地黄cDNA消减文库的构建及分析

    Institute of Scientific and Technical Information of China (English)

    张重义; 范华敏; 杨艳会; 李明杰; 李娟; 许海霞; 陈军营; 陈新建

    2011-01-01

    目的:通过构建连作地黄cDNA消减文库,探讨地黄连作障碍的分子机制.方法:利用抑制性消减杂交(SSH)技术构建连作地黄的正反消减文库,通过蓝白斑筛选、PCR的方法鉴定出阳性克隆,并对其进行测序和生物信息学分析.结果:连作地黄cDNA消减文库构建成功,正向和反向消减文库均筛选了300个阳性克隆.测序结果表明:正库、反库分别获得232条、214条特异的EST序列;经NCBI数据库分析,正库、反库中分别有200,195条EST序列的基因具有蛋白功能注释;COG基因功能预测结果表明,正库、反库中分别有60,61条EST序列具有相应的的基因功能分类,涉及21个代谢途径.结论:差异表达基因的功能注释表明,连作对地黄体内的基因表达具有深刻的影响.本研究筛选地黄响应连作的关键基因,为揭示地黄连作障碍的分子机制奠定了基础.%Objective: To explore the molecular mechanism of continuous monoculture problem by constructing the eDNA libraries of continuous monoculture Rehmannia glutinosa. Method: To use the suppression subtractive hybridization (SSH) technique to construct the forward and reverse subtractive cDNA libraries of continuous monoculture R. glutinosa to adopt blue-white colony sereening and PCR to detect the positive clones which would be sequenced and analyzed by bioinformatics. Result: The subtracted cDNA libraries of continuous monoculture R. glutinosa. were successfully constructed, and the result showed that the forward and reverse subtracted libraries obtained 300 positive clones, respectively. The forward and reverse libraries got different ESTs, and produced 232 ( forward library) and 214 ( reverse library) unique ESTs by sequencing. Based on homology search of BLASTX and BLASTN in NCBI, 200 and 195 of unique ESTs were homologous to known genes in the forward and reverse libraries, respectively. Categories of orthologous group (COG) showed that the forward and reverse

  13. Construction of Yeast One-Hybrid Library for Screening of G-box Binding Proteins%筛选G-box结合蛋白的酵母单杂交文库的构建

    Institute of Scientific and Technical Information of China (English)

    杨鹏程; 周波; 李玉花

    2012-01-01

    目的:筛选花青素合成中的关键基因查尔酮合成酶基因CHS启动子中G-box的结合蛋白,从而找到调节CHS表达的转录因子.方法:采用Matchmaker Gold Yeast One-Hybrid Library Screening System,将CHS启动子G-box序列串联后整合入酵母染色体,构建诱饵菌株;采用SMART技术合成芜菁幼苗下胚轴cDNA,将该cDNA与pGA DT7-Rec表达载体共同转化诱饵菌株,通过同源重组在酵母细胞内同步进行cDNA文库的构建和筛选;用酵母菌落PCR法获得阳性克隆中的cDNA插入片段,测序后在NCBI网站进行Blast分析.结果:共筛选了2.52×106个酵母克隆,得到94个阳性克隆,菌落PCR获得了长度为0.4~2.0 kb的cDNA插入片段,并通过Blast推测了其编码蛋白.结论:实验结果证明酵母单杂交文库构建成功,初步筛选获得了G-box结合蛋白的候选蛋白,为研究CHS的表达调控奠定了基础.%Objective: In order to screen binding proteins of G-box, an important element in chalcone synthase (CHS) promoter region, and find transcriptional regulators of CHS gene. Methods: Matchmaker Gold Yeast One-Hybrid Library Screening System was employed in this study. Bait yeast strain was constructed by synthesizing oligonucleotides containing three tandem copies of G-box core sequences and integrating it into the genome of yeast. The cDNA for hypocotyls of turnip(Brassica rapa L. subsp. rapa Tsuda) was synthesized via SMART technology and co-transformed into bait yeast strain with pGADT7-Rec vector, one-hybrid cDNA library was simultaneously constructed and screened directly in yeast as a result of in vivo plasmid recombination. cDNA inserts in positive clones was amplified by yeast colony PCR and analyzed through NCBI Blast after sequencing. Results: Based on the experiments, we screened 2.52×106 yeast clones and got 94 positive clones. Colony PCR amplification products were 0.4~2.0 kb in length and proteins encoded by them were inferred by NCBI Blast analysis

  14. A Cell-Based Approach for the Biosynthesis/Screening of Cyclic Peptide Libraries against Bacterial Toxins

    Energy Technology Data Exchange (ETDEWEB)

    Camarero, J A; Kimura, R; Woo, Y; Cantor, J; Steenblock, E

    2007-10-24

    Available methods for developing and screening small drug-like molecules able to knockout toxins or pathogenic microorganisms have some limitations. In order to be useful, these new methods must provide high-throughput analysis and identify specific binders in a short period of time. To meet this need, we are developing an approach that uses living cells to generate libraries of small biomolecules, which are then screened inside the cell for activity. Our group is using this new, combined approach to find highly specific ligands capable of disabling anthrax Lethal Factor (LF) as proof of principle. Key to our approach is the development of a method for the biosynthesis of libraries of cyclic peptides, and an efficient screening process that can be carried out inside the cell.

  15. 凡纳滨对虾肌肉组织cDNA全长文库的构建%Construction of the full length cDNA library from muscular tissue of Litopenaeus vannamei

    Institute of Scientific and Technical Information of China (English)

    熊建华; 高永华; 马宁; 盛小伟; 陈晓汉

    2011-01-01

    [目的]为了在短期内获得大量凡纳滨对虾肌肉组织的功能基因表达信息,为深入了解功能基因在凡纳滨对虾肌肉组织中的表达提供分子生物学依据.[方法]通过构建凡纳滨对虾肌肉组织的全长cDNA文库,并进行EST测序分析.[结果]文库质量分析表明,初始文库库容约8.50×106 CFU,重组率在95%左右,插入片断大小为0.54~4.0 kb,多数在1.0 kb以上.随机测序72条cDNA,可得到有功能注释的37条全长cDNA和18条编码未知蛋白的基因序列.通过Gene Ontology功能分类可将有功能注释的37个基因分为蛋白质合成、细胞骨架、细胞信号传导、代谢、转运、能量、转录、抗病及防御、生殖发育和未知功能基因等10类,其中蛋白质合成类基因最多(27.03%).与细胞骨架(13.51%)、细胞信号传导(13.51%)及代谢类基因(13.51%)共占67.56%.[结论]构建凡纳滨对虾肌肉组织的全长cDNA文库,可实现短期内获得大量凡纳滨对虾肌肉组织的功能基因表达信息.%[Objective]The studies had been undertaken in order to understand the biological basis of expression of functional genes in muscular tissue of Litopenaeus vannamei. [Method]The full length cDNA library from muscular tissue of Litopenaeus vannmei was constructed and expressed Sequence Tags (ESTs) were sequenced. [Result]The constructed library was 8.50×106 CFU in capacity with 95% recombinant coefficient. The PCR results showed that the inserts ranged from 0.5 to 4.0 kb and most of them were larger than 1.0 kb. 72 clones were randomly selected and sequenced for full length. Of which, 37 cDNA sequences were identified with known functions, and 18 cDNA sequences remained as unidentiffed. Using gene ontology function classification, 37 cDNA sequences with known function were classified into groups of protein synthesis, cytoskeleton, signal transduction, metabolism, transporter, energy, transcription factors, response to disease

  16. Construction of subtractive cDNA Library of apoptosis-related genes in NB4 cells treated by arsenic trioxide%用抑制性差减杂交构建As_2O_3诱导的NB4细胞凋亡相关基因文库

    Institute of Scientific and Technical Information of China (English)

    狄春红; 顾少华; 谭晓华; 仙玲玲; 吴奇涵; 杨磊

    2009-01-01

    Objective: Construct the gene library of apoptosis related genes in acute promyelocytic leukemia (APL) cell line NB4 cells treated by arsenic trioxide to clarify the apoptotic mechanism of NB4 cells. Method: APL cell line NB4 cells treated with or without arsenic trioxide for 24 hours. Total RNA was extracted and suppress subtractive hybridization (SSH) was conducted according to the manual. With the cDNA of the apoptosis cells as the tester and that of control cells as the driver, forward and reverse hybridization was performed- Differentially expressed genes were linked with pGEM-Teasy cloning vector and transformed into E.coli DH5α. The positive clones were screened by blue and white spot. PCR were used to amplify these genes. Result: The subtractive cDNA libraries related with apoptosis of NB4 cells were successfully constructed. Conclusion: The constructed subtractive libraries are suitable for further study on the functional genes associated with apoptosis of NB4 cells induced by arsenic trioxide.%目的: 构建三氧化二砷(As_2O_3)诱导的急性早幼粒细胞白血病细胞株NB4细胞凋亡相关基因文库.方法:用含4 μmol·L~(-1)As_2O_3和正常培养基培养NB4细胞24 h,抽提总RNA,经逆转录酶合成双链cDNA,分别以砷诱导凋亡组和对照组作为tester和driver,进行双向抑制性差减杂交(supptess-ion sublxactive hybridization,SSH),筛选As_2O_3诱导的NB4细胞凋亡相关基因,将差异表达基因进行PCR扩增并与pGEM-Teasy克隆载体连接,转化DH5 α大肠杆菌,经蓝白斑筛选获得白色阳性克隆,PCR扩增出未知基因片段.结果:成功构建了分别代表在NB4细胞中表达上调和下调的基因文库.结论: 经双向抑制性差减杂交获得了NB4细胞差异表达基因文库,为克隆NB4细胞凋亡相关基因奠定了基础.

  17. Application of a cocktail approach to screen cytochrome P450 BM3 libraries for metabolic activity and diversity.

    Science.gov (United States)

    Reinen, Jelle; Postma, Geert; Tump, Cornelis; Bloemberg, Tom; Engel, Jasper; Vermeulen, Nico P E; Commandeur, Jan N M; Honing, Maarten

    2016-02-01

    In the present study, the validity of using a cocktail screening method in combination with a chemometrical data mining approach to evaluate metabolic activity and diversity of drug-metabolizing bacterial Cytochrome P450 (CYP) BM3 mutants was investigated. In addition, the concept of utilizing an in-house-developed library of CYP BM3 mutants as a unique biocatalytic synthetic tool to support medicinal chemistry was evaluated. Metabolic efficiency of the mutant library towards a selection of CYP model substrates, being amitriptyline (AMI), buspirone (BUS), coumarine (COU), dextromethorphan (DEX), diclofenac (DIC) and norethisterone (NET), was investigated. First, metabolic activity of a selection of CYP BM3 mutants was screened against AMI and BUS. Subsequently, for a single CYP BM3 mutant, the effect of co-administration of multiple drugs on the metabolic activity and diversity towards AMI and BUS was investigated. Finally, a cocktail of AMI, BUS, COU, DEX, DIC and NET was screened against the whole in-house CYP BM3 library. Different validated quantitative and qualitative (U)HPLC-MS/MS-based analytical methods were applied to screen for substrate depletion and targeted product formation, followed by a more in-depth screen for metabolic diversity. A chemometrical approach was used to mine all data to search for unique metabolic properties of the mutants and allow classification of the mutants. The latter would open the possibility of obtaining a more in-depth mechanistic understanding of the metabolites. The presented method is the first MS-based method to screen CYP BM3 mutant libraries for diversity in combination with a chemometrical approach to interpret results and visualize differences between the tested mutants.

  18. Locating sweet spots for screening hits and evaluating pan-assay interference filters from the performance analysis of two lead-like libraries.

    Science.gov (United States)

    Mok, N Yi; Maxe, Sara; Brenk, Ruth

    2013-03-25

    The efficiency of automated compound screening is heavily influenced by the design and the quality of the screening libraries used. We recently reported on the assembly of one diverse and one target-focused lead-like screening library. Using data from 15 enzyme-based screenings conducted using these libraries, their performance was investigated. Both libraries delivered screening hits across a range of targets, with the hits distributed across the entire chemical space represented by both libraries. On closer inspection, however, hit distribution was uneven across the chemical space, with enrichments observed in octants characterized by compounds at the higher end of the molecular weight and lipophilicity spectrum for lead-like compounds, while polar and sp(3)-carbon atom rich compounds were underrepresented among the screening hits. Based on these observations, we propose that screening libraries should not be evenly distributed in lead-like chemical space but be enriched in polar, aliphatic compounds. In conjunction with variable concentration screening, this could lead to more balanced hit rates across the chemical space and screening hits of higher ligand efficiency will be captured. Apart from chemical diversity, both screening libraries were shown to be clean from any pan-assay interference (PAINS) behavior. Even though some compounds were flagged to contain PAINS structural motifs, some of these motifs were demonstrated to be less problematic than previously suggested. To maximize the diversity of the chemical space sampled in a screening campaign, we therefore consider it justifiable to retain compounds containing PAINS structural motifs that were apparently clean in this analysis when assembling screening libraries.

  19. 光皮桦茎叶cDNA文库构建及部分EST序列SSR分析%Library construction of cDNA and SSR analysis of partial ESTs for stem and leaf of Betula luminifera

    Institute of Scientific and Technical Information of China (English)

    张敏; 黄华宏; 林二培; 周厚君; 王亚辉; 童再康

    2012-01-01

    A cDNA library of stem and leaf from Betula luminifera was constructed.The primary titer of cDNA library was about 1.5×106 pfu/mL,its recombinant efficiency reached 97.3%,and the size of insert DNA fragments ranged from 0.5 to 3.0 kb,with an average of 1.3 kb.The results indicated that it was a higher-quality cDNA library,and could be used in gene cloning and gene expression profile analysis.Distribution and frequency of SSRs were analyzed in 224 non-redundant ESTs from B.luminifera cDNA library,using online searching software.The results showed that 60 SSRs distributed in 47 EST sequences,accounting for 26.80% of all ESTs.Dinucleotide would be the major repeat types,accounting for 70.00% of the total number of acquired SSRs.The tri-nucleotide and tetra-nucleotide repeats accounted for 28.30% and 1.70% respectively.This research might lay the foundation for designing the targeted EST-SSR primers and genetic diversity analysis by mining the information of EST-SSR loci in B.luminifera EST sequence data.%以光皮桦茎叶组织为材料,构建了cDNA文库。初级文库滴度为1.5×106pfu/mL,重组率达97.3%,插入片段大小在0.5~3.0kb之间,平均长度约为1.3kb,表明所构建的文库质量较高,可用于后续基因克隆及基因表达谱的研究。利用微卫星查找软件对获得的224条EST序列进行微卫星位点搜寻及其丰度、分布比较,发现47条序列含微卫星位点60个,占全部EST序列的26.80%;在所有SSRs中二碱基重复最多,为42个,占总数的70.00%,含三、四碱基重复分别占总数的28.30%和1.70%。通过对光皮桦EST序列中微卫星位点信息的发掘分析,为有针对性地设计EST-SSR引物、进行遗传多样性分析奠定了基础。

  20. 龙须菜四分孢子体cDNA文库的构建%Construction of a cDNA Library from the Tetrasporophyte of Gracilaria lemaneiformis (Rhodophyceae)

    Institute of Scientific and Technical Information of China (English)

    孙雪; 张学成; 隋正红; 茅云翔

    2003-01-01

    为了研究不同世代和性别基因表达谱的差异,本文构建了龙须菜(Gracilaria lemaneiformis)四分孢子体的cDNA文库.总RNA提取使用RNeasy Plant Mini Kit(Qiagen),cDNA文库构建使用SMART cDNA Library Construction Kit(Clontech),包装蛋白购自Promega公司.该cDNA文库含有1.28×106个克隆,扩增文库的滴度是1.98×109 pfu/mL,重组频率是85.0%,插入片段几乎全部集中在500~1500 bp之间.

  1. Construction and analysis of antennal cDNA library from rice striped stem borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae), and expression profiles of putative odorant-binding protein and chemosensory protein genes.

    Science.gov (United States)

    Gong, Zhong-Jun; Liu, Su; Jiang, Yan-Dong; Zhou, Wen-Wu; Liang, Qing-Mei; Cheng, Jiaan; Zhang, Chuan-Xi; Zhu, Zeng-Rong; Gurr, Geoff M

    2015-05-01

    In this study, we constructed a high-quality cDNA library from the antennae of the Chilo suppressalis (Walker) (Lepidoptera: Pyralidae). A total of 1,235 colonies with inserts greater than 0.7 kb were sequenced and analyzed. Homology searching coupled with bioinformatics analysis identified 15 and 7 cDNA sequences, respectively, encoding putative odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). A phylogenetic tree of CsupCSPs showed that each CsupCSP has orthologs in Manduca sexta and Bombyx mori with strong bootstrapping support. One CSP was either very specific or more related to the CSPs of another species than to conspecific CSP. The expression profiles of the OBPs and CSPs in different tissues were measured by real-time quantitative PCR. The results revealed that of the 11 OBP genes, the transcript levels of CsupOBP1, CsupOBP5, and CsupOBP7 were higher in both male and female antennae than those in other tissues. And CsupCSP7 was highly expressed in both male and female antennae. Based on these results, the possible physiological functions of CsupOBPs and CsupCSPs were discussed.

  2. Phylogeny-function analysis of (meta)genomic libraries: screening for expression of ribosomal RNA genes by large-insert library fluorescent in situ hybridization (LIL-FISH).

    Science.gov (United States)

    Leveau, Johan H J; Gerards, Saskia; de Boer, Wietse; van Veen, Johannes A

    2004-09-01

    We assessed the utility of fluorescent in situ hybridization (FISH) in the screening of clone libraries of (meta)genomic or environmental DNA for the presence and expression of bacterial ribosomal RNA (rRNA) genes. To establish proof-of-principle, we constructed a fosmid-based library in Escherichia coli of large-sized genomic DNA fragments of the mycophagous soil bacterium Collimonas fungivorans, and hybridized 768 library clones with the Collimonas-specific fluorescent probe CTE998-1015. Critical to the success of this approach (which we refer to as large-insert library FISH or LIL-FISH) was the ability to induce fosmid copy number, the exponential growth status of library clones in the FISH assay and the use of a simple pooling strategy to reduce the number of hybridizations. Twelve out of 768 E. coli clones were suspected to harbour and express Collimonas 16S rRNA genes based on their hybridization to CTE998-1015. This was confirmed by the finding that all 12 clones were also identified in an independent polymerase chain reaction-based screening of the same 768 clones using a primer set for the specific detection of Collimonas 16S ribosomal DNA (rDNA). Fosmids isolated from these clones were grouped by restriction analysis into two distinct contigs, confirming that C. fungivorans harbours at least two 16S rRNA genes. For one contig, representing 1-2% of the genome, the nucleotide sequence was determined, providing us with a narrow but informative view of Collimonas genome structure and content.

  3. 败血症鲢肝与肾cDNA文库构建及MHC class Ⅰ的克隆与分析%Construction of a cDNA library and cloning of the MHC class Ⅰ gene in silver carp (Hypophthalmichthys molitrix) infected with bacterial septicemia

    Institute of Scientific and Technical Information of China (English)

    汪登强; 罗晓松; 陈大庆

    2011-01-01

    Silver carp (Hypophthalmichthys molitrix) is one of the most commonly cultured freshwater species in China. However, the development of silver carp aquaculture is threatened by bacterial septicemia. To isolate and study genes relevant to the disease, we constructed a cDNA library from silver carp liver and kidney tissue using a CloneMiner? cDNA kit. The primary cDNA library titer was 1.34× 107 cfu/mL yielding 2.68×l07cfu recombi-nants with 97.5% positive clones. The exogenous inserts of the recombinants ranged in size from 0.8 to 3.5 kb. We attempted to sequence 80 positive clones from both terminals to test the completeness of the coding sequence. We successfully sequenced 74 clones, of which 49 contained the complete coding sequence. Among the clones successfully sequenced, 57 sequences were identified to 49 known genes in GenBank. The cDNA library was subsequently screened by PCR yielding a single clone containing the complete coding sequence for MHC class I. The H. Molitrix MHC class I was 1 026 bp long and encoded a 341 amino acid (aa) protein that included a leader peptide, a\\, a2, a3, and transmembrane and cytosolic domains of 16, 88, 90, 87, and 60 aa, respectively. In addition, we identified sites that were highly conserved among vertebrate MHC class I. Phylogenetic comparison of the complete coding sequences and the a3 domain ofhH, molitrix MHC class I with other vertebrate species revealed different topology, suggesting a different evolutionary history for different domains of MHC class I and the occurrence of gene recombination among cyprinidae.%采用CloneMinerTM cDNA文库构建试剂盒构建了患败血症的鲢(Hypophthalmichthys molitrix)肝和肾的cDNA文库.经检验,文库的滴度为1.34×107 cfu/mL,总库容为2.68×107 cfu,阳性克隆率为97.5%,平均插入片段大于1.2 kb.对80个随机挑选的克隆进行两端测序,结果显示有74个测序成功.经在GenBank上BLAST比对,其中57个为已知功能基因,属于45

  4. Nylon-3 copolymers that generate cell-adhesive surfaces identified by library screening.

    Science.gov (United States)

    Lee, Myung-Ryul; Stahl, Shannon S; Gellman, Samuel H; Masters, Kristyn S

    2009-11-25

    Polymers in the nylon-3 family contain subunits derived from beta-amino acids, which are linked to one another via amide bonds. Thus, the nylon-3 backbone is homologous to the alpha-amino acid-based backbone of proteins. This molecular-level homology suggests that nylon-3 materials might be intrinsically protein-mimetic. The experiments described here explore this prospect in the context of cell adhesion, with tissue engineering as a long-range goal. We have evaluated a small library of sequence-random nylon-3 copolymers for the ability to render surfaces attractive to NIH 3T3 fibroblast adhesion and spreading. Library screening was accomplished in a high-throughput, parallel mode via attachment of the copolymers in a two-dimensional array to a modified glass surface. Significant variations in fibroblast adhesion and spreading were observed as a function of nylon-3 subunit identity and proportion. Several of the nylon-3 copolymers supported cell adhesion and morphology that was comparable, or even superior, to that achieved on positive control substrates such as tissue culture polystyrene and collagen-coated glass. Moreover, studies conducted under serum-free conditions demonstrated that specific nylon-3 derivatives supported cell adhesion independently of serum protein adsorption. Although cell adhesion was diminished in the absence of serum, particular copolymers demonstrated an ability to support substantially greater cell adhesion than any of the other conditions, including the positive controls. The nylon-3 copolymers that were most effective at promoting adhesion to a modified glass surface proved also to be effective at promoting adhesion when attached to a PEG-based hydrogel, demonstrating the potential for these copolymers to be used in tissue engineering applications.

  5. Tetanus Neurotoxin Neutralizing Antibodies Screened from a Human Immune scFv Antibody Phage Display Library.

    Science.gov (United States)

    Wang, Han; Yu, Rui; Fang, Ting; Yu, Ting; Chi, Xiangyang; Zhang, Xiaopeng; Liu, Shuling; Fu, Ling; Yu, Changming; Chen, Wei

    2016-09-11

    Tetanus neurotoxin (TeNT) produced by Clostridium tetani is one of the most poisonous protein substances. Neutralizing antibodies against TeNT can effectively prevent and cure toxicosis. Using purified Hc fragments of TeNT (TeNT-Hc) as an antigen, three specific neutralizing antibody clones recognizing different epitopes were selected from a human immune scFv antibody phage display library. The three antibodies (2-7G, 2-2D, and S-4-7H) can effectively inhibit the binding between TeNT-Hc and differentiated PC-12 cells in vitro. Moreover, 2-7G inhibited TeNT-Hc binding to the receptor via carbohydrate-binding sites of the W pocket while 2-2D and S-4-7H inhibited binding of the R pocket. Although no single mAb completely protected mice from the toxin, they could both prolong survival when challenged with 20 LD50s (50% of the lethal dose) of TeNT. When used together, the mAbs completely neutralized 1000 LD50s/mg Ab, indicating their high neutralizing potency in vivo. Antibodies recognizing different carbohydrate-binding pockets could have higher synergistic toxin neutralization activities than those that recognize the same pockets. These results could lead to further production of neutralizing antibody drugs against TeNT and indicate that using TeNT-Hc as an antigen for screening human antibodies for TeNT intoxication therapy from human immune antibody library was convenient and effective.

  6. Tetanus Neurotoxin Neutralizing Antibodies Screened from a Human Immune scFv Antibody Phage Display Library

    Science.gov (United States)

    Wang, Han; Yu, Rui; Fang, Ting; Yu, Ting; Chi, Xiangyang; Zhang, Xiaopeng; Liu, Shuling; Fu, Ling; Yu, Changming; Chen, Wei

    2016-01-01

    Tetanus neurotoxin (TeNT) produced by Clostridium tetani is one of the most poisonous protein substances. Neutralizing antibodies against TeNT can effectively prevent and cure toxicosis. Using purified Hc fragments of TeNT (TeNT-Hc) as an antigen, three specific neutralizing antibody clones recognizing different epitopes were selected from a human immune scFv antibody phage display library. The three antibodies (2-7G, 2-2D, and S-4-7H) can effectively inhibit the binding between TeNT-Hc and differentiated PC-12 cells in vitro. Moreover, 2-7G inhibited TeNT-Hc binding to the receptor via carbohydrate-binding sites of the W pocket while 2-2D and S-4-7H inhibited binding of the R pocket. Although no single mAb completely protected mice from the toxin, they could both prolong survival when challenged with 20 LD50s (50% of the lethal dose) of TeNT. When used together, the mAbs completely neutralized 1000 LD50s/mg Ab, indicating their high neutralizing potency in vivo. Antibodies recognizing different carbohydrate-binding pockets could have higher synergistic toxin neutralization activities than those that recognize the same pockets. These results could lead to further production of neutralizing antibody drugs against TeNT and indicate that using TeNT-Hc as an antigen for screening human antibodies for TeNT intoxication therapy from human immune antibody library was convenient and effective. PMID:27626445

  7. Tetanus Neurotoxin Neutralizing Antibodies Screened from a Human Immune scFv Antibody Phage Display Library

    Directory of Open Access Journals (Sweden)

    Han Wang

    2016-09-01

    Full Text Available Tetanus neurotoxin (TeNT produced by Clostridium tetani is one of the most poisonous protein substances. Neutralizing antibodies against TeNT can effectively prevent and cure toxicosis. Using purified Hc fragments of TeNT (TeNT-Hc as an antigen, three specific neutralizing antibody clones recognizing different epitopes were selected from a human immune scFv antibody phage display library. The three antibodies (2-7G, 2-2D, and S-4-7H can effectively inhibit the binding between TeNT-Hc and differentiated PC-12 cells in vitro. Moreover, 2-7G inhibited TeNT-Hc binding to the receptor via carbohydrate-binding sites of the W pocket while 2-2D and S-4-7H inhibited binding of the R pocket. Although no single mAb completely protected mice from the toxin, they could both prolong survival when challenged with 20 LD50s (50% of the lethal dose of TeNT. When used together, the mAbs completely neutralized 1000 LD50s/mg Ab, indicating their high neutralizing potency in vivo. Antibodies recognizing different carbohydrate-binding pockets could have higher synergistic toxin neutralization activities than those that recognize the same pockets. These results could lead to further production of neutralizing antibody drugs against TeNT and indicate that using TeNT-Hc as an antigen for screening human antibodies for TeNT intoxication therapy from human immune antibody library was convenient and effective.

  8. A two-host fosmid system for functional screening of (meta)genomic libraries from extreme thermophiles.

    Science.gov (United States)

    Angelov, Angel; Mientus, Markus; Liebl, Susanne; Liebl, Wolfgang

    2009-05-01

    A new cloning system is described, which allows the construction of large-insert fosmid libraries in Escherichia coli and the transfer of the recombinant libraries to the extreme thermophile Thermus thermophilus via natural transformation. Libraries are established in the thermophilic host by site-specific chromosomal insertion of the recombinant fosmids via single crossover or double crossover recombination at the T. thermophilus pyr locus. Comparative screening of a fosmid library constructed from genomic DNA from the thermophilic spirochaete, Spirochaeta thermophila, for clones expressing thermoactive xylanase activity revealed that 50% of the fosmids that conferred xylanase activity upon the corresponding T. thermophilus transformants did not give rise to xylanase-positive E. coli clones, indicating that significantly more S. thermophila genes are functionally expressed in T. thermophilus than in E. coli. The novel T. thermophilus host/vector system may be of value for the construction and functional screening of recombinant DNA libraries from individual thermophilic or extremely thermophilic organisms as well as from complex metagenomes isolated from thermophilic microbial communities.

  9. Porcine transcriptome analysis based on 97 non-normalized cDNA libraries and assembly of 1,021,891 expressed sequence tags

    DEFF Research Database (Denmark)

    Gorodkin, Jan; Cirera, Susanna; Hedegaard, Jacob;

    2007-01-01

    of genes between different tissues, in particular brain/spinal cord, and found patterns of correlation between genes that share expression in pairs of libraries. Finally, there was remarkable agreement in expression between specialized tissues according to Gene Ontology categories. CONCLUSION: This EST......BACKGROUND: Knowledge of the structure of gene expression is essential for mammalian transcriptomics research. We analyzed a collection of more than one million porcine expressed sequence tags (ESTs), of which two-thirds were generated in the Sino-Danish Pig Genome Project and one-third are from...... approximately 25% have a high confidence match to UniProt. Approximately 6,000 new porcine gene clusters were identified. Expression analysis based on the non-normalized libraries resulted in the following findings. The distribution of cluster sizes is scaling invariant. Brain and testes are among the tissues...

  10. Porcine transcriptome analysis based on 97 non-normalized cDNA libraries and assembly of 1,021,891 expressed sequence tags

    DEFF Research Database (Denmark)

    Gorodkin, Jan; Cirera, Susanna; Hedegaard, Jakob;

    2007-01-01

    of genes between different tissues, in particular brain/spinal cord, and found patterns of correlation between genes that share expression in pairs of libraries. Finally, there was remarkable agreement in expression between specialized tissues according to Gene Ontology categories. Conclusion: This EST......Background: Knowledge of the structure of gene expression is essential for mammalian transcriptomics research. We analyzed a collection of more than one million porcine expressed sequence tags (ESTs), of which two-thirds were generated in the Sino-Danish Pig Genome Project and one-third are from...... approximately 25% have a high confidence match to UniProt. Approximately 6,000 new porcine gene clusters were identified. Expression analysis based on the non-normalized libraries resulted in the following findings. The distribution of cluster sizes is scaling invariant. Brain and testes are among the tissues...

  11. Identification of a novel skin penetration enhancement peptide by phage display peptide library screening.

    Science.gov (United States)

    Kumar, Sunny; Sahdev, Preety; Perumal, Omathanu; Tummala, Hemachand

    2012-05-07

    Skin is an important site for local or systemic application of drugs. However, a majority of drugs have poor permeability through the skin's topmost layer, stratum corneum (SC). The aim of this study was to identify safe and smaller peptides that could enhance the skin penetration of drug molecules. By screening phage display peptide library, we have identified a T2 peptide (LVGVFH), which enhanced the penetration of bacteriophages (~800 nm long bacterial viruses) across porcine and mouse skin. Pretreating the skin with synthetic T2 peptide at pH 4.5 resulted in significant penetration enhancement of hydrophilic drug 5-fluorouracil (5-FU) across skin. FTIR spectroscopy showed that the T2 peptide interacted with skin lipids to enhance the skin penetration. Pretreating the skin with T2 peptide enhanced the partitioning of small molecules with different lipophilicities (5-FU, fluorescein isothiocyanate, and rhodamine 123 hydrochloride) into skin. Fluorescence studies showed that T2 peptide enhanced the diffusion of these molecules into intercellular lipids of SC and thus enhanced the penetration into the skin. Histidine at the c-terminus of T2 peptide was identified to be critical for the skin penetration enhancement. T2 peptide interacted with skin lipids to cause skin penetration enhancement. The study identified a novel, safe, and noninvasive peptide to improve the skin penetration of drugs without chemical conjugation.

  12. SCREENING OF PROTEASE ENZYME BY CONSTRUCTION OF METAGENOMIC LIBRARY FROM MARINE SOIL SEDIMENTS

    Directory of Open Access Journals (Sweden)

    R.PRABAVATHI

    2012-07-01

    Full Text Available Nonetheless, the cultivable microorganisms constituting these resources correspond to only a small fraction of the microbial diversity less than 1% of the microorganisms in various environments are readily cultivable (Amann et al., 1995. This limits the range of a search for new biocatalysts for the bioprocess industry, so the use of complex communities and the effort to overcome the problem of noncultivability attract not only scientific attention but also biotechnological innovation. Methods have been developed and used toovercome the non-cultivability of environmental microorganisms for biotechnology, namely cloning and the expression of metagenomes in suitable expression hosts. Proteases are present in all living forms as they are involved in various metabolic processes. They are mainly involved in hydrolysis of the peptide bonds (Gupta et al., 2002. Proteases find a wide range of applications in food, pharmaceutical, leather and textile, detergent, diagnostics industries and also in waste management. In order to discover new proteases from metagenomiclibraries, we screened for proteolytic activity from a constructed metagenomic library by direct cloning of environmental DNA of large DNA inserts. A novel gene encoding proteolytic enzyme was picked up,sequenced, expressed in E. coli and characterized. Several microbial proteases from the culturable organisms have been characterized. However, very few proteases have been identified through culture independent metagenomic approach.

  13. Screening of a specific peptide binding to esophageal squamous carcinoma cells from phage displayed peptide library.

    Science.gov (United States)

    Ma, Caixia; Li, Chunyan; Jiang, Dongliang; Gao, Xiaojie; Han, Juanjuan; Xu, Nan; Wu, Qiong; Nie, Guochao; Chen, Wei; Lin, Fenghuei; Hou, Yingchun

    2015-06-01

    To select a specifically binding peptide for imaging detection of human esophageal squamous cell carcinoma (ESCC), a phage-displayed 12-mer peptide library was used to screen the peptide that bind to ESCC cells specifically. After four rounds of bio-panning, the phage recovery rate gradually increased, and specific phage clones were effectively enriched. The 60 randomly selected phage clones were tested using cellular enzyme-linked immunosorbent assay (ELISA), and 41 phage clones were identified as positive clones with the over 2.10 ratio of absorbance higher than other clones, IRP and PBS controls. From the sequencing results of the positive clones, 14 peptide sequences were obtained and ESCP9 consensus sequence was identified as the peptide with best affinity to ESCC cells via competitive inhibition, fluorescence microscopy, and flow cytometry. The results indicate that the peptide ESCP9 can bind to ESCC cells specifically and sensitively, and it is a potential candidate to be developed as an useful molecule to the imaging detection and targeting therapy for ESCC.

  14. Speeding up the screening of steroids in urine: development of a user-friendly library.

    Science.gov (United States)

    Galesio, M; López-Fdez, H; Reboiro-Jato, M; Gómez-Meire, Silvana; Glez-Peña, D; Fdez-Riverola, F; Lodeiro, Carlos; Diniz, M E; Capelo, J L

    2013-12-11

    This work presents a novel database search engine - MLibrary - designed to assist the user in the detection and identification of androgenic anabolic steroids (AAS) and its metabolites by matrix assisted laser desorption/ionization (MALDI) and mass spectrometry-based strategies. The detection of the AAS in the samples was accomplished by searching (i) the mass spectrometric (MS) spectra against the library developed to identify possible positives and (ii) by comparison of the tandem mass spectrometric (MS/MS) spectra produced after fragmentation of the possible positives with a complete set of spectra that have previously been assigned to the software. The urinary screening for anabolic agents plays a major role in anti-doping laboratories as they represent the most abused drug class in sports. With the help of the MLibrary software application, the use of MALDI techniques for doping control is simplified and the time for evaluation and interpretation of the results is reduced. To do so, the search engine takes as input several MALDI-TOF-MS and MALDI-TOF-MS/MS spectra. It aids the researcher in an automatic mode by identifying possible positives in a single MS analysis and then confirming their presence in tandem MS analysis by comparing the experimental tandem mass spectrometric data with the database. Furthermore, the search engine can, potentially, be further expanded to other compounds in addition to AASs. The applicability of the MLibrary tool is shown through the analysis of spiked urine samples.

  15. Protein stability regulators screening assay (Pro-SRSA): protein degradation meets the CRISPR-Cas9 library.

    Science.gov (United States)

    Wu, Yuanzhong; Kang, Tiebang

    2016-06-29

    The regulation of protein stability is a fundamental issue for biophysical processes, but there has not previously been a convenient and unbiased method of identifying regulators of protein stability. However, as reported in the article entitled "A genome-scale CRISPR-Cas9 screening method for protein stability reveals novel regulators of Cdc25A," recently published in Cell Discovery, our team developed a protein stability regulators screening assay (Pro-SRSA) by combining the whole-genome clustered regularly interspaced short palindromic repeats Cas9 (CRISPR-Cas9) library with a dual-fluorescence-based protein stability reporter and high-throughput sequencing to screen for regulators of protein stability. Based on our findings, we are confident that this efficient and unbiased screening method at the genome scale will be used by researchers worldwide to identify regulators of protein stability.

  16. Construction of genome-wide physical BAC contigs using mapped cDNA as probes: Toward an integrated BAC library resource for genome sequencing and analysis. Annual report, July 1995--January 1997

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, S.C.; Bocskai, D.; Cao, Y. [and others

    1997-12-31

    The goal of human genome project is to characterize and sequence entire genomes of human and several model organisms, thus providing complete sets of information on the entire structure of transcribed, regulatory and other functional regions for these organisms. In the past years, a number of useful genetic and physical markers on human and mouse genomes have been made available along with the advent of BAC library resources for these organisms. The advances in technology and resource development made it feasible to efficiently construct genome-wide physical BAC contigs for human and other genomes. Currently, over 30,000 mapped STSs and 27,000 mapped Unigenes are available for human genome mapping. ESTs and cDNAs are excellent resources for building contig maps for two reasons. Firstly, they exist in two alternative forms--as both sequence information for PCR primer pairs, and cDoreen genomic libraries efficiently for large number of DNA probes by combining over 100 cDNA probes in each hybridization. Second, the linkage and order of genes are rather conserved among human, mouse and other model organisms. Therefore, gene markers have advantages over random anonymous STSs in building maps for comparative genomic studies.

  17. Anchoring a Defined Sequence to the 55' Ends of mRNAs : The Bolt to Clone Rare Full Length mRNAs and Generate cDNA Libraries porn a Few Cells.

    Science.gov (United States)

    Baptiste, J; Milne Edwards, D; Delort, J; Mallet, J

    1993-01-01

    Among numerous applications, the polymerase chain reaction (PCR) (1,2) provides a convenient means to clone 5' ends of rare mRNAs and to generate cDNA libraries from tissue available in amounts too low to be processed by conventional methods. Basically, the amplification of cDNAs by the PCR requires the availability of the sequences of two stretches of the molecule to be amplified. A sequence can easily be imposed at the 5' end of the first-strand cDNAs (corresponding to the 3' end of the mRNAs) by priming the reverse transcription with a specific primer (for cloning the 5' end of rare messenger) or with an oligonucleotide tailored with a poly (dT) stretch (for cDNA library construction), taking advantage of the poly (A) sequence that is located at the 3' end of mRNAs. Several strategies have been devised to tag the 3' end of the ss-cDNAs (corresponding to the 55' end of the mRNAs). We (3) and others have described strategies based on the addition of a homopolymeric dG (4,5) or dA (6,7) tail using terminal deoxyribonucleotide transferase (TdT) ("anchor-PCR" [4]). However, this strategy has important limitations. The TdT reaction is difficult to control and has a low efficiency (unpublished observations). But most importantly, the return primers containing a homopolymeric (dC or dT) tail generate nonspecific amplifications, a phenomenon that prevents the isolation of low abundance mRNA species and/or interferes with the relative abundance of primary clones in the library. To circumvent these drawbacks, we have used two approaches. First, we devised a strategy based on a cRNA enrichment procedure, which has been useful to eliminate nonspecific-PCR products and to allow detection and cloning of cDNAs of low abundance (3). More recently, to avoid the nonspecific amplification resulting from the annealing of the homopolymeric tail oligonucleotide, we have developed a novel anchoring strategy that is based on the ligation of an oligonucleotide to the 35' end of ss

  18. Quantitative digital image analysis of chromogenic assays for high throughput screening of alpha-amylase mutant libraries.

    Science.gov (United States)

    Shankar, Manoharan; Priyadharshini, Ramachandran; Gunasekaran, Paramasamy

    2009-08-01

    An image analysis-based method for high throughput screening of an alpha-amylase mutant library using chromogenic assays was developed. Assays were performed in microplates and high resolution images of the assay plates were read using the Virtual Microplate Reader (VMR) script to quantify the concentration of the chromogen. This method is fast and sensitive in quantifying 0.025-0.3 mg starch/ml as well as 0.05-0.75 mg glucose/ml. It was also an effective screening method for improved alpha-amylase activity with a coefficient of variance of 18%.

  19. A general strategy for antibody library screening via conversion of transient target binding into permanent reporter deposition.

    Science.gov (United States)

    Maaß, Alexander; Heiseler, Tim; Maaß, Franziska; Fritz, Janine; Hofmeyer, Thomas; Glotzbach, Bernhard; Becker, Stefan; Kolmar, Harald

    2014-02-01

    We report here a generally applicable method for the selective covalent attachment of a reporter molecule to a replicating entity that allows one to obtain specific binders from a single round of library screening. We show that selective biotinylation of phage particles displaying a binder to any given target can be achieved by application of a coupled enzyme reaction on the surface of the target-binding phage particles that includes a peroxidase, an oxidase and a catalase. Due to the covalent linkage of biotin together with the tight and stable interaction of biotin with streptavidin, very stringent wash conditions for removal of nonspecific binders can be applied. The method termed (3)CARD (triple catalytic reporter deposition) was successfully applied to single-round screening of a phage display library of camelid single-domain antibodies against three different target proteins.

  20. Synthesis and agrochemical screening of a library of natural product-like bicyclo[2,2,2]octenones.

    Science.gov (United States)

    Smith, Stephen C; James, Donald R; Abelman, Matthew M; Sexton, Graham J

    2005-11-01

    A general route to a series of differentially substituted bicyclo[2,2,2]octenones has been developed, making use of the in situ intramolecular Diels Alder reaction of masked ortho-benzoquinones. This approach was used to synthesize a series of thirteen key acid-containing templates from which a solution phase discovery library of 1126 diverse amides was then constructed. The rigid polycyclic nature of the templates and the prevalence of oxygenated functionality confer natural product-like qualities and three-dimensional diversity. The library was screened in HTS in vivo against a number of weed, insect and fungal model organisms leading to the discovery of a novel series of herbicidally active compounds. The development, production and biological activity of the library are described.

  1. 中国美利奴超细型与哈萨克羊毛囊兴盛期皮肤组织消减cDNA文库的构建%Construction of Subtractive cDNA Library of Skin Tissue in Follicle Anagen Between Chinese Merino and Kazakh Sheep

    Institute of Scientific and Technical Information of China (English)

    杨剑波; 甘尚权; 李晶; 高磊; 杨井泉; 张科; 杨永林; 沈敏; 石国庆

    2012-01-01

    [Objective] The aim of the study is to screen important candidate genes influencing wool traits in sheep, and to lay a theoretical foundation for exploring the molecular mechanism of wool traits formation. [Method] Using suppression subtractive hybridzation (SSH) technique, positive and reverse subtracted cDNA library between skin tissue in follicle anagen of Chinese Merino (superfine type) and Kazakh sheep was constructed, respectively. Genes of differential expression profiles were sequenced for bioinformatics analysis. Semi-quantitative RT-PCR and real-time fluorescent quantitative RT-PCR methods were used to assess partial genes of differential expression profiles. [Result] A total of 153 and 143 ESTs were obtained from the forward and reverse subtracted cDNA library, respectively. Among these ESTs, 5 from positive library and 4 from reverse library of unknown function were identified and speculated as novel genes. The GO cluster, pathway and protein-protein interaction analysis of the partial ESTs of known function showed that there were certain differences between coarse wool and fine wool sheep. The three differential genes from the constrcted cDNA libraries, KRTAP8-2, Trichohyalin and KRTAP3-2 genes were all specifically expressed at high level in the skin. The abundance of KRTAP8-2 and Trichohyalin genes mRNA in skin of Chinese Merino was 3.45 and 2.07 times than that of Kazakh sheep, respectively, while the abundance of KRTAP3-2 gene mRNA in skin of Kazakh sheep was 1.87 times than that of Chinese Merino. [Conclusion] The subtracted cDNA library of skin tissue between Chinese Merino and Kazakh sheep was successfully constructed, a batch of ESTs with differential expression profiles which possibly influence woo! Traits were initially screened.%[目的]筛选影响绵羊羊毛性状的重要候选基因,为研究羊毛性状形成的分子机制奠定基础.[方法]利用抑制性消减杂交技术构建中国美利奴超细型和哈萨克羊兴盛期皮

  2. Functional Metagenomics: Construction and High-Throughput Screening of Fosmid Libraries for Discovery of Novel Carbohydrate-Active Enzymes.

    Science.gov (United States)

    Ufarté, Lisa; Bozonnet, Sophie; Laville, Elisabeth; Cecchini, Davide A; Pizzut-Serin, Sandra; Jacquiod, Samuel; Demanèche, Sandrine; Simonet, Pascal; Franqueville, Laure; Veronese, Gabrielle Potocki

    2016-01-01

    Activity-based metagenomics is one of the most efficient approaches to boost the discovery of novel biocatalysts from the huge reservoir of uncultivated bacteria. In this chapter, we describe a highly generic procedure of metagenomic library construction and high-throughput screening for carbohydrate-active enzymes. Applicable to any bacterial ecosystem, it enables the swift identification of functional enzymes that are highly efficient, alone or acting in synergy, to break down polysaccharides and oligosaccharides.

  3. Construction of cDNA Libraries and Identification of Head Kidney from Scomberomorus niphonius%蓝点马鲛头肾cDNA文库的构建及鉴定

    Institute of Scientific and Technical Information of China (English)

    王丹妮; 刘军

    2015-01-01

    研究运用SMART技术对蓝点马鲛头肾构建了cDNA文库,该文库原始文库滴度为2.26×106pfu/mL,文库容量为1.36×106pfu,符合文库构建的要求。从文库中随机挑选24个单克隆菌,以载体的通用引物进行菌落检测PCR,结果表明:重组率为95.8%,插入片段大小平均为1000bp。该文库的构建满足了基因的分离与筛选,为进一步研究其相关基因克隆及分子生物学研究奠定基础。%cDNA library of Scomberomorus niphonius head kidney was constracted by SMART technology. The original library titer is 2.26×106pfu/mL,and library capacity is 1.36×106pfu,meeting the requirements of library construction. RandomLy selected 24 monoclonal bacteria from the library,subjected to colony PCR detected by using universal primers. The results showed that recombination rate was 95.8%,an average in⁃sert size was 1 000bp. Construction of the library meet the isolation and screening of gene,and lay the foundation for further study of melecμlar biology and gene cloning.

  4. High-throughput screening of thin-film semiconductor material libraries II: characterization of Fe-W-O libraries.

    Science.gov (United States)

    Meyer, Robert; Sliozberg, Kirill; Khare, Chinmay; Schuhmann, Wolfgang; Ludwig, Alfred

    2015-04-13

    Metal oxides are promising materials for solar water splitting. To identify suitable materials within the ternary system FeWO, thin-film material libraries with combined thickness and compositional gradients were synthesized by combinatorial reactive magnetron sputtering. These libraries (>1000 different samples) were investigated by means of structural and functional high-throughput characterization techniques to establish correlations between composition, crystallinity, morphology, thickness, and photocurrent density in the compositional range between (Fe6 W94 )Ox and (Fe61 W39 )Ox . In addition to the well-known phase WO3 , the binary phase W5 O14 and the ternary phase Fe2 O6 W show enhanced photoelectrochemical activity. The highest photocurrent density of 65 μA cm(-2) was achieved for the composition (Fe15 W85 )Ox , which contains the W5 O14 phase and has a thickness of 1060 nm.

  5. Screening of a chemical library by HT-G4-FID for discovery of selective G-quadruplex binders.

    Science.gov (United States)

    Largy, Eric; Saettel, Nicolas; Hamon, Florian; Dubruille, Sylvie; Teulade-Fichou, Marie-Paule

    2012-01-01

    Due to the lack of structural guidelines about G-quadruplex ligands, rational design cannot be the only approach to discover potent G4-ligands. As a complementary approach, screening of chemical library may provide interesting scaffolds known as hits provided that specific tools are available. In this work, the Institut Curie-CNRS chemical library was firstly screened by chemoinformatics methods. Similarity estimations by comparison with reference compounds (Phen-DC3, 360A, MMQ12) provided a set of molecules, which were then evaluated by high-throughput G4-FID (HT-G4-FID) against various G-quadruplex DNA. A full investigation of the most interesting molecules, using the HT-G4-FID assay and molecular modeling, supplied an interesting structure-activity relationship confirming the efficiency of this general approach. Overall, we demonstrated that HT-G4-FID coupled with screening of chemical libraries is a powerful tool to identify new G4-DNA binding scaffolds.

  6. Isolation and characterization of cDNA encoding the alpha subunit of Cap Z(36/32), an actin-capping protein from the Z line of skeletal muscle.

    OpenAIRE

    Casella, J F; Casella, S J; Hollands, J. A.; Caldwell, J E; Cooper, J A

    1989-01-01

    cDNA encoding the alpha chain of Cap Z has been isolated by screening a lambda gt11 library with affinity-purified antibodies. A single cDNA insert (designated CE2) of 2153 base pairs (bp) contains an open reading frame of 836 bp, which is incomplete at its 5' end. The technique of "rapid amplification of cDNA ends" has been used to extend the 5' end of this open reading frame to a potential transcription initiation site that is preceded by 320 bp of an apparently untranslated region. The pro...

  7. Construction and diversity analysis of a murine IgE phage surface display library

    Institute of Scientific and Technical Information of China (English)

    LIZONGDONG; MINGYEH

    1997-01-01

    To make further investigation of the IgE antibody repertoire in Trichosanthin (TCS) allergic responses,a murine IgE phage surface display library was constructed (3.0×105 independent clones).We first constructed the Vε cDNA library (4.6×105 independent clones) and Vκ cDNA library (3.0×105 independent clones).Then,the Vε and Vκgene segments were amplified from both libraries by PCR respectively,and assembled into Fab fragment by SOE PCR.The phage library containing Fabs was thus constructed.The diversity of Vε from this library was analyzed and proved.Fab clones with high specificity to TCS have been screened out.

  8. A targeted library screen reveals a new inhibitor scaffold for protein kinase D.

    Directory of Open Access Journals (Sweden)

    Manuj Tandon

    Full Text Available Protein kinase D (PKD has emerged as a potential therapeutic target in multiple pathological conditions, including cancer and heart diseases. Potent and selective small molecule inhibitors of PKD are valuable for dissecting PKD-mediated cellular signaling pathways and for therapeutic application. In this study, we evaluated a targeted library of 235 small organic kinase inhibitors for PKD1 inhibitory activity at a single concentration. Twenty-eight PKD inhibitory chemotypes were identified and six exhibited excellent PKD1 selectivity. Five of the six lead structures share a common scaffold, with compound 139 being the most potent and selective for PKD vs PKC and CAMK. Compound 139 was an ATP-competitive PKD1 inhibitor with a low double-digit nanomolar potency and was also cell-active. Kinase profiling analysis identified this class of small molecules as pan-PKD inhibitors, confirmed their selectivity again PKC and CAMK, and demonstrated an overall favorable selectivity profile that could be further enhanced through structural modification. Furthermore, using a PKD homology model based on similar protein kinase structures, docking modes for compound 139 were explored and compared to literature examples of PKD inhibition. Modeling of these compounds at the ATP-binding site of PKD was used to rationalize its high potency and provide the foundation for future further optimization. Accordingly, using biochemical screening of a small number of privileged scaffolds and computational modeling, we have identified a new core structure for highly potent PKD inhibition with promising selectivity against closely related kinases. These lead structures represent an excellent starting point for the further optimization and the design of selective and therapeutically effective small molecule inhibitors of PKD.

  9. High-throughput library screening identifies two novel NQO1 inducers in human lung cells.

    Science.gov (United States)

    Tan, Xiang-Lin; Marquardt, Gaby; Massimi, Aldo B; Shi, Miao; Han, Weiguo; Spivack, Simon D

    2012-03-01

    Many phytochemicals possess antioxidant and cancer-preventive properties, some putatively through antioxidant response element-mediated phase II metabolism, entailing mutagen/oxidant quenching. In our recent studies, however, most candidate phytochemical agents were not potent in inducing phase II genes in normal human lung cells. In this study, we applied a messenger RNA (mRNA)-specific gene expression-based high throughput in vitro screening approach to discover new, potent plant-derived phase II inducing chemopreventive agents. Primary normal human bronchial epithelial (NHBE) cells and immortalized human bronchial epithelial cells (HBECs) were exposed to 800 individual compounds in the MicroSource Natural Products Library. At a level achievable in humans by diet (1.0 μM), 2,3-dihydroxy-4-methoxy-4'-ethoxybenzophenone (DMEBP), triacetylresveratrol (TRES), ivermectin, sanguinarine sulfate, and daunorubicin induced reduced nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1 (NQO1) mRNA and protein expression in NHBE cells. DMEBP and TRES were the most attractive agents as coupling potency and low toxicity for induction of NQO1 (mRNA level, ≥3- to 10.8-fold that of control; protein level, ≥ two- to fourfold that of control). Induction of glutathione S-transferase pi mRNA expression was modest, and none was apparent for glutathione S-transferase pi protein expression. Measurements of reactive oxygen species and glutathione/oxidized glutathione ratio showed an antioxidant effect for DMEBP, but no definite effect was found for TRES in NHBE cells. Exposure of NHBE cells to H(2)O(2) induced nuclear translocation of nuclear factor erythroid 2-related factor 2, but this translocation was not significantly inhibited by TRES and DMEBP. These studies show that potency and low toxicity may align for two potential NQO1-inducing agents, DMEBP and TRES.

  10. Large-scale screening of a targeted Enterococcus faecalis mutant library identifies envelope fitness factors.

    Directory of Open Access Journals (Sweden)

    Lionel Rigottier-Gois

    Full Text Available Spread of antibiotic resistance among bacteria responsible for nosocomial and community-acquired infections urges for novel therapeutic or prophylactic targets and for innovative pathogen-specific antibacterial compounds. Major challenges are posed by opportunistic pathogens belonging to the low GC% gram-positive bacteria. Among those, Enterococcus faecalis is a leading cause of hospital-acquired infections associated with life-threatening issues and increased hospital costs. To better understand the molecular properties of enterococci that may be required for virulence, and that may explain the emergence of these bacteria in nosocomial infections, we performed the first large-scale functional analysis of E. faecalis V583, the first vancomycin-resistant isolate from a human bloodstream infection. E. faecalis V583 is within the high-risk clonal complex 2 group, which comprises mostly isolates derived from hospital infections worldwide. We conducted broad-range screenings of candidate genes likely involved in host adaptation (e.g., colonization and/or virulence. For this purpose, a library was constructed of targeted insertion mutations in 177 genes encoding putative surface or stress-response factors. Individual mutants were subsequently tested for their i resistance to oxidative stress, ii antibiotic resistance, iii resistance to opsonophagocytosis, iv adherence to the human colon carcinoma Caco-2 epithelial cells and v virulence in a surrogate insect model. Our results identified a number of factors that are involved in the interaction between enterococci and their host environments. Their predicted functions highlight the importance of cell envelope glycopolymers in E. faecalis host adaptation. This study provides a valuable genetic database for understanding the steps leading E. faecalis to opportunistic virulence.

  11. New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam Ruditapes philippinarum challenged by the protozoan parasite Perkinsus olseni

    Science.gov (United States)

    Kang, Hyun-Sil; Hong, Hyun-Ki; Park, Kyung-Il; Cho, Moonjae; Youn, Seok-Hyun; Choi, Kwang-Sik

    2017-02-01

    Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.

  12. New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam Ruditapes philippinarum challenged by the protozoan parasite Perkinsus olseni

    Science.gov (United States)

    Kang, Hyun-Sil; Hong, Hyun-Ki; Park, Kyung-Il; Cho, Moonjae; Youn, Seok-Hyun; Choi, Kwang-Sik

    2017-03-01

    Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.

  13. A novel approach for immunization, screening and characterization of selected scFv libraries using membrane fractions of tumor cells.

    Science.gov (United States)

    Tur, Mehmet Kemal; Rothe, Achim; Huhn, Michael; Goerres, Ute; Klimka, Alexander; Stöcker, Michael; Engert, Andreas; Fischer, Rainerr; Finner, Ricarda; Barth, Stefan

    2003-04-01

    Isolation of cell-surface specific antibodies prerequisites the functional expressing of antigens on intact cells, which are maintained routinely by cell culturing. However, long-term culturing of tumor cells could alter their antigen expression patterns and stable fixation of whole cells is not guaranteed on plastic surfaces during stringent screening procedures. We prepared functional breast cancer cell-membrane fractions that express surface molecules in their native conformation. Specific binding phages were isolated from phage antibody libraries constructed from the spleen messenger RNA of mice immunized with breast cancer cell-membrane fractions. After negative selection on non-mammary carcinoma cells and four rounds of positive selection on breast carcinoma cell lines, phage antibodies were enriched that bound specifically to breast cancer cell lines as confirmed by phage enzyme linked immunosorbent assay (ELISA) using 96-well plates coated with breast cancer cell membranes. The isolated phage antibodies were highly specific for the breast cancer cell line 8701-BC but not on other carcinoma such as the Hodgkin-derived cell line L540Cy as demonstrated by ELISA and flow cytometry. This report describes a rapid and more versatile method for isolating antibody fragments compared to whole cell screening procedures. One single membrane preparation can be stored for at least 15 months at -80 degrees C and used to immunize mice or for screening of antibody libraries. The selection and screening strategy used should be generally applicable to identify novel cell-surface antigens and their corresponding antibodies.

  14. The hunt for original microbial enzymes: an initiatory review on the construction and functional screening of (metagenomic libraries

    Directory of Open Access Journals (Sweden)

    Martin, M.

    2016-01-01

    Full Text Available Introduction. Discovering novel enzymes is of interest in both applied and basic science. Microbial enzymes, which are incredibly diverse and easy to produce, are increasingly sought by diverse approaches. Literature. This review first distinguishes culture-based from culture-independent methods, detailing within each group the advantages and drawbacks of sequence- and function-based methods. It then discusses the main factors affecting the success of endeavors to identify novel enzymes through construction and functional screening of genomic or metagenomic libraries: the sampled environment, how DNA is extracted and processed, the vector used (plasmid, cosmid, fosmid, BAC, or shuttle vector, the host cell chosen from the available prokaryotic and eukaryotic ones and the main screening steps. Conclusions. Library construction and screening can be tricky and requires expertise. Combining different strategies, such as working with cultivable and non-cultivable organisms, using sequence- and function-based approaches, or performing multihost screenings, is probably the best way to identify novel and diverse enzymes from an environmental sample.

  15. A novel salt-tolerant chitobiosidase discovered by genetic screening of a metagenomic library derived from chitin-amended agricultural soil

    NARCIS (Netherlands)

    Cretoiu, Mariana Silvia; Berini, Francesca; Kielak, Anna Maria; Marinelli, Flavia; van Elsas, Jan Dirk

    2015-01-01

    Here, we report on the construction of a metagenomic library from a chitin-amended disease-suppressive agricultural soil and its screening for genes that encode novel chitinolytic enzymes. The library, constructed in fosmids in an Escherichia coli host, comprised 145,000 clones containing inserts of

  16. Synthesis of solution-phase phosphoramidite and phosphite ligand libraries and their in situ screening in the rhodium-catalyzed asymmetric addition of arylboronic acids

    NARCIS (Netherlands)

    Jagt, Richard B. C.; Toullec, Patrick Y.; Schudde, Ebe P.; de Vries, Johannes G.; Feringa, Ben L.; Minnaard, Adriaan J.

    2007-01-01

    Herein, we report the automated parallel synthesis of solution-phase libraries of phosphoramidite ligands for the development of enantioselective catalysts. The ligand libraries are screened in situ in the asymmetric rhodium-catalyzed addition of arylboronic acids to aldehydes and imines. It is show

  17. Coupled high-throughput functional screening and next generation sequencing for identification of plant polymer decomposing enzymes in metagenomic libraries

    Directory of Open Access Journals (Sweden)

    Mari eNyyssönen

    2013-09-01

    Full Text Available Recent advances in sequencing technologies generate new predictions and hypotheses about the functional roles of environmental microorganisms. Yet, until we can test these predictions at a scale that matches our ability to generate them, most of them will remain as hypotheses. Function-based mining of metagenomic libraries can provide direct linkages between genes, metabolic traits and microbial taxa and thus bridge this gap between sequence data generation and functional predictions. Here we developed high-throughput screening assays for function-based characterization of activities involved in plant polymer decomposition from environmental metagenomic libraries. The multiplexed assays use fluorogenic and chromogenic substrates, combine automated liquid handling and use a genetically modified expression host to enable simultaneous screening of 12,160 clones for 14 activities in a total of 170,240 reactions. Using this platform we identified 374 (0.26 % cellulose, hemicellulose, chitin, starch, phosphate and protein hydrolyzing clones from fosmid libraries prepared from decomposing leaf litter. Sequencing on the Illumina MiSeq platform, followed by assembly and gene prediction of a subset of 95 fosmid clones, identified a broad range of bacterial phyla, including Actinobacteria, Bacteroidetes, multiple Proteobacteria sub-phyla in addition to some Fungi. Carbohydrate-active enzyme genes from 20 different glycoside hydrolase families were detected. Using tetranucleotide frequency binning of fosmid sequences, multiple enzyme activities from distinct fosmids were linked, demonstrating how biochemically-confirmed functional traits in environmental metagenomes may be attributed to groups of specific organisms. Overall, our results demonstrate how functional screening of metagenomic libraries can be used to connect microbial functionality to community composition and, as a result, complement large-scale metagenomic sequencing efforts.

  18. Coupled high-throughput functional screening and next generation sequencing for identification of plant polymer decomposing enzymes in metagenomic libraries.

    Science.gov (United States)

    Nyyssönen, Mari; Tran, Huu M; Karaoz, Ulas; Weihe, Claudia; Hadi, Masood Z; Martiny, Jennifer B H; Martiny, Adam C; Brodie, Eoin L

    2013-01-01

    Recent advances in sequencing technologies generate new predictions and hypotheses about the functional roles of environmental microorganisms. Yet, until we can test these predictions at a scale that matches our ability to generate them, most of them will remain as hypotheses. Function-based mining of metagenomic libraries can provide direct linkages between genes, metabolic traits and microbial taxa and thus bridge this gap between sequence data generation and functional predictions. Here we developed high-throughput screening assays for function-based characterization of activities involved in plant polymer decomposition from environmental metagenomic libraries. The multiplexed assays use fluorogenic and chromogenic substrates, combine automated liquid handling and use a genetically modified expression host to enable simultaneous screening of 12,160 clones for 14 activities in a total of 170,240 reactions. Using this platform we identified 374 (0.26%) cellulose, hemicellulose, chitin, starch, phosphate and protein hydrolyzing clones from fosmid libraries prepared from decomposing leaf litter. Sequencing on the Illumina MiSeq platform, followed by assembly and gene prediction of a subset of 95 fosmid clones, identified a broad range of bacterial phyla, including Actinobacteria, Bacteroidetes, multiple Proteobacteria sub-phyla in addition to some Fungi. Carbohydrate-active enzyme genes from 20 different glycoside hydrolase (GH) families were detected. Using tetranucleotide frequency (TNF) binning of fosmid sequences, multiple enzyme activities from distinct fosmids were linked, demonstrating how biochemically-confirmed functional traits in environmental metagenomes may be attributed to groups of specific organisms. Overall, our results demonstrate how functional screening of metagenomic libraries can be used to connect microbial functionality to community composition and, as a result, complement large-scale metagenomic sequencing efforts.

  19. A Novel Dual Expression Platform for High Throughput Functional Screening of Phage Libraries in Product like Format.

    Directory of Open Access Journals (Sweden)

    Xiaodong Xiao

    Full Text Available High throughput screenings of single chain Fv (scFv antibody phage display libraries are currently done as soluble scFvs produced in E.coli. Due to endotoxin contaminations from bacterial cells these preparations cannot be reliably used in mammalian cell based assays. The monovalent nature and lack of Fc in soluble scFvs prevent functional assays that are dependent on target cross linking and/or Fc functions. A convenient approach is to convert scFvs into scFv.Fc fusion proteins and express them in mammalian cell lines for screening. This approach is low throughput and is only taken after primary screening of monovalent scFvs that are expressed in bacteria. There is no platform at present that combines the benefits of both bacterial and mammalian expression system for screening phage library output. We have, therefore, developed a novel dual expression vector, called pSplice, which can be used to express scFv.Fc fusion proteins both in E.coli and mammalian cell lines. The hallmark of the vector is an engineered intron which houses the bacterial promoter and signal peptide for expression and secretion of scFv.Fc in E.coli. When the vector is transfected into a mammalian cell line, the intron is efficiently spliced out resulting in a functional operon for expression and secretion of the scFv.Fc fusion protein into the culture medium. By applying basic knowledge of mammalian introns and splisosome, we designed this vector to enable screening of phage libraries in a product like format. Like IgG, the scFv.Fc fusion protein is bi-valent for the antigen and possesses Fc effector functions. Expression in E.coli maintains the speed of the bacterial expression platform and is used to triage clones based on binding and other assays that are not sensitive to endotoxin. Triaged clones are then expressed in a mammalian cell line without the need for any additional cloning steps. Conditioned media from the mammalian cell line containing the fusion proteins

  20. 黄瓜幼果cDNA文库构建与EST测序分析%Construction of a Young Fruit cDNA Library and EST Sequencing in Cucumis sativus

    Institute of Scientific and Technical Information of China (English)

    潘宇; 蒲志群; 肖雅文; 赵名琛; 郑浴; 石士涛; 胡小燕; 张兴国

    2013-01-01

    将黄瓜授粉前后多个发育阶段的幼果组织等量混合后提取总RNA和mRNA,以λTriplEx2为栽体、XL1-Blue为宿主茵,构建了1个黄瓜幼果cDNA文库;其滴度为1.165×106pfu/mL,重组率在94.4%左右.测序获得116条EST,92.2%的长度在400 bp以上,19%为重叠序列.在GenBank中进行BLAST分析后确认与已知功能基因相似的EST序列有71条,有相似序列而功能未知的基因和没有相似序列的EST序列各占19.83%和18.97%.从对文库的检验结果看,构建的cDNA文库重组率较高,库容达到预期要求.%The growth and development of cucumber (Cucumis sativus L.) fruit is closely related to its yield and quality.To gain the gene expression pattern of the young fruit just before and after pollination is important to exploring the molecular mechanisms of parthenocarpy and fruit growth initiation.In this study,tissues of young fruit of cucumber at different development stages before and after pollination were mixed and total RNA and mRNA were extracted.Then,a cDNA library of cucumber young fruit with a titer of 1.165 × 106 pfu/mL and a recombinant frequency of 94.4% was constructed,using λTriplEx2 as a vector and XL1-Blue as the host strain.One hundred and sixteen EST sequences were obtained,of which 92.2% were over 400 bp in size and 19% were contigs.BLAST analysis in GenBank revealed that 71 of the 116 ESTs were homologous to genes of known function,19.83% were related to genes with unknown functions and 18.97 % were novel.The cDNA library sufficed the criteria with high recombinant efficiency and wide representativeness.The results will facilitate the cloning of development-related genes from cucumber fruit.

  1. cDNA cloning, sequence analysis, and chromosomal localization of the gene for human carnitine palmitoyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Finocchiaro, G.; Taroni, F.; Martin, A.L.; Colombo, I.; Tarelli, G.T.; DiDonato, S. (Istituto Nazionale Neurologico C. Besta, Milan (Italy)); Rocchi, M. (Istituto G. Gaslini, Genoa (Italy))

    1991-01-15

    The authors have cloned and sequenced a cDNA encoding human liver carnitine palmitoyltransferase an inner mitochondrial membrane enzyme that plays a major role in the fatty acid oxidation pathway. Mixed oligonucleotide primers whose sequences were deduced from one tryptic peptide obtained from purified CPTase were used in a polymerase chain reaction, allowing the amplification of a 0.12-kilobase fragment of human genomic DNA encoding such a peptide. A 60-base-pair (bp) oligonucleotide synthesized on the basis of the sequence from this fragment was used for the screening of a cDNA library from human liver and hybridized to a cDNA insert of 2255 bp. This cDNA contains an open reading frame of 1974 bp that encodes a protein of 658 amino acid residues including 25 residues of an NH{sub 2}-terminal leader peptide. The assignment of this open reading frame to human liver CPTase is confirmed by matches to seven different amino acid sequences of tryptic peptides derived from pure human CPTase and by the 82.2% homology with the amino acid sequence of rat CPTase. The NH{sub 2}-terminal region of CPTase contains a leucine-proline motif that is shared by carnitine acetyl- and octanoyltransferases and by choline acetyltransferase. The gene encoding CPTase was assigned to human chromosome 1, region 1q12-1pter, by hybridization of CPTase cDNA with a DNA panel of 19 human-hanster somatic cell hybrids.

  2. Molecular cloning and nucleotide sequence of cDNA for human liver arginase

    Energy Technology Data Exchange (ETDEWEB)

    Haraguchi, Y.; Takiguchi, M.; Amaya, Y.; Kawamoto, S.; Matsuda, I.; Mori, M.

    1987-01-01

    Arginase (EC3.5.3.1) catalyzes the last step of the urea cycle in the liver of ureotelic animals. Inherited deficiency of the enzyme results in argininemia, an autosomal recessive disorder characterized by hyperammonemia. To facilitate investigation of the enzyme and gene structures and to elucidate the nature of the mutation in argininemia, the authors isolated cDNA clones for human liver arginase. Oligo(dT)-primed and random primer human liver cDNA libraries in lambda gt11 were screened using isolated rat arginase cDNA as a probe. Two of the positive clones, designated lambda hARG6 and lambda hARG109, contained an overlapping cDNA sequence with an open reading frame encoding a polypeptide of 322 amino acid residues (predicted M/sub r/, 34,732), a 5'-untranslated sequence of 56 base pairs, a 3'-untranslated sequence of 423 base pairs, and a poly(A) segment. Arginase activity was detected in Escherichia coli cells transformed with the plasmid carrying lambda hARG6 cDNA insert. RNA gel blot analysis of human liver RNA showed a single mRNA of 1.6 kilobases. The predicted amino acid sequence of human liver arginase is 87% and 41% identical with those of the rat liver and yeast enzymes, respectively. There are several highly conserved segments among the human, rat, and yeast enzymes.

  3. Cloning a Full-length cDNA Encoding UDP-glucose Pyrophosphorylase from Amorpha fruticosa by PCR-based Methods

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A method based on degenerate Oligo-primed polymerase chain reaction (PCR) and random amplification of cDNA end (RACE) PCR for cloning a full-length cDNA is described. An Amorpha fruticosa cDNA clone encoding UDP-glucose pyrophosphorylase (UGP), a key enzyme producing UDP-glucose in the synthesis of sucrose and cell ulose, is cloned by using this method. We design 5' RACE primers based on UGP A1 fragment, which obtains from degenerate PCR. Inverse PCR and nested PCR enable cloning of the remainder 5' and 3' end fragments of the gene. The deduced amino acid sequence exhibits significant homology with the other UGP genes cloned. This method is more simple and inexpensive than screening cDNA library, and can be easily adapted to clone other genes.

  4. Generation and analysis of a large-scale expressed sequence Tag database from a full-length enriched cDNA library of developing leaves of Gossypium hirsutum L.

    Directory of Open Access Journals (Sweden)

    Min Lin

    Full Text Available BACKGROUND: Cotton (Gossypium hirsutum L. is one of the world's most economically-important crops. However, its entire genome has not been sequenced, and limited resources are available in GenBank for understanding the molecular mechanisms underlying leaf development and senescence. METHODOLOGY/PRINCIPAL FINDINGS: In this study, 9,874 high-quality ESTs were generated from a normalized, full-length cDNA library derived from pooled RNA isolated from throughout leaf development during the plant blooming stage. After clustering and assembly of these ESTs, 5,191 unique sequences, representative 1,652 contigs and 3,539 singletons, were obtained. The average unique sequence length was 682 bp. Annotation of these unique sequences revealed that 84.4% showed significant homology to sequences in the NCBI non-redundant protein database, and 57.3% had significant hits to known proteins in the Swiss-Prot database. Comparative analysis indicated that our library added 2,400 ESTs and 991 unique sequences to those known for cotton. The unigenes were functionally characterized by gene ontology annotation. We identified 1,339 and 200 unigenes as potential leaf senescence-related genes and transcription factors, respectively. Moreover, nine genes related to leaf senescence and eleven MYB transcription factors were randomly selected for quantitative real-time PCR (qRT-PCR, which revealed that these genes were regulated differentially during senescence. The qRT-PCR for three GhYLSs revealed that these genes express express preferentially in senescent leaves. CONCLUSIONS/SIGNIFICANCE: These EST resources will provide valuable sequence information for gene expression profiling analyses and functional genomics studies to elucidate their roles, as well as for studying the mechanisms of leaf development and senescence in cotton and discovering candidate genes related to important agronomic traits of cotton. These data will also facilitate future whole-genome sequence

  5. 致农民肺嗜热吸水链霉菌cDNA文库的构建及体外表达%Construction of cDNA library and antigen expression of Streptomyces Thermohydroscopicus in vitro

    Institute of Scientific and Technical Information of China (English)

    凌媛; 王玲玲; 刘朔; 马列; 王群; 张丽娇; 何晓雨; 赵明静; 王笑歌

    2013-01-01

    目的 构建致农民肺嗜热吸水链霉菌cDNA文库并进行EST测序,通过生物信息学软件分析EST序列同源性及生物学功能,筛选重组阳性基因克隆进行体外表达.方法 利用SMART方法构建致农民肺嗜热吸水链霉菌的cDNA文库,随机挑选重组阳性克隆进行EST测序.挑选有关目的基因连接入pET-28a载体并转化大肠埃希菌BL2 (DE3),IPTG诱导体外表达.结果 该文库的重组率为96.3%,是一个较高质量的文库.从文库中随即挑选的1 020个重组阳性的克隆,获得978个有义序列,平均长度为495 bp,含有347个单一基因,同源性比较发现部分序列与猪胸膜肺炎放线菌外膜蛋白(omla),转铁蛋白B(TbpB)具有较高的同源性,分别为51%和42%.将重组阳性的基因克隆至载体中,IPTG诱导得到表达产物的相对分子质量分别为63×10 3和30× 103.结论 所构建的致农民肺嗜热吸水链霉菌cDNA文库包含全部EST序列,可能包含嗜热吸水链霉菌相关疾病巨大部分毒力分子,这些数据的积累将有助于农民肺特异性毒力分子的进一步筛选,同时为研究农民肺的发病机制奠定基础,如果能准确筛选出相关毒力基因,将为农民肺血清学诊断以及特异性疫苗的研发奠定基础.%Objective To construct the cDNA library of Streptomyces Thermohydroscopicus and to express some of the specific antigens in vitro.Methods The cDNA library of Streptomyces Thermohydroscopicus was constructed by switching mechanism at 5'end of RNA transcript approach.The recombinant positive clones were selected randomly for EST sequencing and two candidate genes were sub-cloned into expression vector pET-28a.The recombinants were then transformed into BL2 (DE3) and proteins were expressed by the induction of IPTG.Results A high-quality cDNA library of Streptomyces Thermohydroscopicus was constructed with the recombination rate of 96.3%.A set of 978 valid sequences were obtained out of total 1020

  6. Identification of B. anthracis N(5)-carboxyaminoimidazole ribonucleotide mutase (PurE) active site binding compounds via fragment library screening.

    Science.gov (United States)

    Lei, Hao; Jones, Christopher; Zhu, Tian; Patel, Kavankumar; Wolf, Nina M; Fung, Leslie W-M; Lee, Hyun; Johnson, Michael E

    2016-02-15

    The de novo purine biosynthesis pathway is an attractive target for antibacterial drug design, and PurE from this pathway has been identified to be crucial for Bacillus anthracis survival in serum. In this study we adopted a fragment-based hit discovery approach, using three screening methods-saturation transfer difference nucleus magnetic resonance (STD-NMR), water-ligand observed via gradient spectroscopy (WaterLOGSY) NMR, and surface plasmon resonance (SPR), against B. anthracis PurE (BaPurE) to identify active site binding fragments by initially testing 352 compounds in a Zenobia fragment library. Competition STD NMR with the BaPurE product effectively eliminated non-active site binding hits from the primary hits, selecting active site binders only. Binding affinities (dissociation constant, KD) of these compounds varied between 234 and 301μM. Based on test results from the Zenobia compounds, we subsequently developed and applied a streamlined fragment screening strategy to screen a much larger library consisting of 3000 computationally pre-selected fragments. Thirteen final fragment hits were confirmed to exhibit binding affinities varying from 14μM to 700μM, which were categorized into five different basic scaffolds. All thirteen fragment hits have ligand efficiencies higher than 0.30. We demonstrated that at least two fragments from two different scaffolds exhibit inhibitory activity against the BaPurE enzyme.

  7. 噬菌体抗体库筛选技术%Screening Isolates from Antibody Phage-display Libraries

    Institute of Scientific and Technical Information of China (English)

    高鹏; 胡立勇; 钱钰; 徐晨

    2012-01-01

    For almost 20 years, phage display antibody (Ab) libraries screening have been widely used in antibody screen, clinical diagnostic, treatment of disease and basic research areas. Rapid identification of the autofit monoclonal antibody, and reliable and efficient data management and analysis are very important in the application of this technology. This review described reported methods for high-throughput screening of antibody phage-display libraries and further more gave a brief introduction to data management.%在过去的20年中,噬菌体抗体库筛选技术被广泛的应用于抗体筛选、疾病治疗,临床诊断以及基础研究之中.在该技术的应用过程中,快速有效的筛选出最适合的单克隆抗体并进行可靠和高效的数据管理和分析是十分重要的.文中总结了近年来噬菌体抗体库的高通量筛选方法并且对数据管理做了简要介绍.

  8. Development of microsatellite markers for common bean (Phaseolus vulgaris L.) based on screening of non-enriched, small-insert genomic libraries.

    Science.gov (United States)

    Blair, Matthew W; Torres, Monica Muñoz; Pedraza, Fabio; Giraldo, Martha C; Buendía, Hector F; Hurtado, Natalia

    2009-09-01

    Microsatellite markers are useful genetic tools for a wide array of genomic analyses although their development is time-consuming and requires the identification of simple sequence repeats (SSRs) from genomic sequences. Screening of non-enriched, small-insert libraries is an effective method of SSR isolation that can give an unbiased picture of motif frequency. Here we adapt high-throughput protocols for the screening of plasmid-based libraries using robotic colony picking and filter preparation. Seven non-enriched genomic libraries from common bean genomic DNA were made by digestion with four frequently cutting restriction enzymes, double digestion with a frequently cutting restriction enzyme and a less frequently cutting restriction enzyme, or sonication. Library quality was compared and three of the small-insert libraries were selected for further analysis. Each library was plated and picked into 384-well plates that were used to create high-density filter arrays of over 18 000 clones each, which were screened with oligonucleotide probes for various SSR motifs. Positive clones were found to have low redundancy. One hundred SSR markers were developed and 80 were tested for polymorphism in a standard parental survey. These microsatellite markers derived from non-SSR-enriched libraries should be useful additions to previous markers developed from enriched libraries.

  9. Identification of Bacterial Surface Antigens by Screening Peptide Phage Libraries Using Whole Bacteria Cell-Purified Antisera

    Science.gov (United States)

    Hu, Yun-Fei; Zhao, Dun; Yu, Xing-Long; Hu, Yu-Li; Li, Run-Cheng; Ge, Meng; Xu, Tian-Qi; Liu, Xiao-Bo; Liao, Hua-Yuan

    2017-01-01

    Bacterial surface proteins can be good vaccine candidates. In the present study, we used polyclonal antibodies purified with intact Erysipelothrix rhusiopthiae to screen phage-displayed random dodecapeptide and loop-constrained heptapeptide libraries, which led to the identification of mimotopes. Homology search of the mimotope sequences against E. rhusiopthiae-encoded ORF sequences revealed 14 new antigens that may localize on the surface of E. rhusiopthiae. When these putative surface proteins were used to immunize mice, 9/11 antigens induced protective immunity. Thus, we have demonstrated that a combination of using the whole bacterial cells to purify antibodies and using the phage-displayed peptide libraries to determine the antigen specificities of the antibodies can lead to the discovery of novel bacterial surface antigens. This can be a general approach for identifying surface antigens for other bacterial species. PMID:28184219

  10. Genome-Wide Screening of Genes Showing Altered Expression in Liver Metastases of Human Colorectal Cancers by cDNA Microarray

    Directory of Open Access Journals (Sweden)

    Rempei Yanagawa

    2001-01-01

    Full Text Available In spite of intensive and increasingly successful attempts to determine the multiple steps involved in colorectal carcinogenesis, the mechanisms responsible for metastasis of colorectal tumors to the liver remain to be clarified. To identify genes that are candidates for involvement in the metastatic process, we analyzed genome-wide expression profiles of 10 primary colorectal cancers and their corresponding metastatic lesions by means of a cDNA microarray consisting of 9121 human genes. This analysis identified 40 genes whose expression was commonly upregulated in metastatic lesions, and 7 that were commonly downregulated. The upregulated genes encoded proteins involved in cell adhesion, or remodeling of the actin cytoskeleton. Investigation of the functions of more of the altered genes should improve our understanding of metastasis and may identify diagnostic markers and/or novel molecular targets for prevention or therapy of metastatic lesions.

  11. Expression screening of bacterial libraries of recombinant alpha-1 proteinase inhibitor variants for candidates with thrombin inhibitory capacity.

    Science.gov (United States)

    Bhakta, Varsha; Gierczak, Richard F; Sheffield, William P

    2013-12-01

    Exhaustive mutagenesis studies of the reactive centre loop (RCL), a key structural component of proteins belonging to the serpin superfamily of protease inhibitors, are complicated by the size of the RCL, serpin conformational complexity, and, for most serpins, the lack of a serpin-dependent phenotype of expressing cells. Here, we describe a thrombin capture assay that distinguished thrombin-inhibitory recombinant human alpha-1 proteinase inhibitor (API M358R) from non-inhibitory API variants in Escherichia coli lysates prepared from either single clones or pools. Binding of API proteins in the lysates to thrombin immobilized on microtiter plate wells was quantified via colour generated by a peroxidase-coupled anti-API antibody. Bacterial expression plasmids encoding inhibitory API M358R were mixed 1:99 with plasmids encoding non-inhibitory API T345R/M358R and the resulting library screened in pools of 10. All above-background signals arising from pools or subsequently re-probed single clones were linked to the presence of plasmids encoding API M358R. Screening of a portion of another expression library encoding hypervariable API with all possibilities at codons 352-358 also yielded only novel, thrombin-inhibitory variants. Probing a smaller library expressing all possible codons at Ala347 yielded the wild type, 6 different functional variants, one partially active variant, and two variants with no thrombin-inhibitory activity. API antigen levels varied considerably less among Ala347 variants than activity levels, and comparison of rate constants of inhibition of purified API variants to their corresponding thrombin capture assay lysate values was used to establish the sensitivity and specificity of the assay. The results indicate that the approach is sufficiently robust to correctly identify functional versus non-functional candidates in API expression libraries, and could be of value in systematically probing structure/function relationships not only in the API

  12. High-throughput screening of one-bead-one-compound libraries: identification of cyclic peptidyl inhibitors against calcineurin/NFAT interaction.

    Science.gov (United States)

    Liu, Tao; Qian, Ziqing; Xiao, Qing; Pei, Dehua

    2011-09-12

    One-bead-one-compound (OBOC) libraries provide a powerful tool for drug discovery as well as biomedical research. However, screening a large number of beads/compounds (>1 million) and rank ordering the initial hits (which are covalently attached to a solid support) according to their potencies still post significant technical challenges. In this work, we have integrated some of the latest technical advances from our own as well as other laboratories to develop a general methodology for rapidly screening large OBOC libraries. The methodology has been applied to synthesize and screen a cyclic peptide library that features: (1) spatially segregated beads containing cyclic peptides on the surface layer and linear encoding peptides in their interior; (2) rapid on-bead screening of the library (>1 million) by a multistage procedure (magnetic bead sorting, enzyme-linked assay, and fluorescence based screening); (3) selective release of cyclic peptides from single positive beads for solution-phase determination of their binding affinities; and (4) hit identification by partial Edman degradation/mass spectrometry (PED/MS). Screening of the library against protein phosphatase calcineurin (Cn) identified a series of cyclic peptides that bind to the substrate-docking site for nuclear factor of activated T cells (NFAT) with K(D) values of ∼1 μM. Further improvement of the affinity and specificity of these compounds may lead to a new class of immunosuppressive agents that are more selective and therefore less toxic than cyclosporine A and FK506.

  13. 枣抑制消减cDNA文库构建与分析%Construction and analysis of suppression subtractive cDNA library in Chinese date (Ziziphus jujube)

    Institute of Scientific and Technical Information of China (English)

    魏琦琦; 段经华; 冯延芝; 李芳东; 张琳

    2016-01-01

    Z. jujube shows some special characters of flowering and fruit bearing. In order to obtain genes involved in blossom development, two suppression subtractive cDNA libraries were constructed using developing blossoms of‘Jinsi No.4’ as tester and leaves as driver. The recombination rates of the SSH libraries from Z. jujube’s flowers and leaves were 92.05% and 90.26%, with the length of inserted fragments ranged from 200 to 2 000 bp, and mainly focusing on 1 000 bp. A total of 1 000 positive clones were randomly selected from the SSH libraries ofZ. jujube’s flowers and leaves respectively for DNA sequencing and assembled. Consequently, 43 contigs, 53 singletons, 73 ORFs, 96 unigenes and 20 annotated sequences were obtained from SSH library ofZ. jujube’s flowers. Forty-ifve contigs, 41 singletons, 70 ORFs, 86 unigenes and 23 annotated sequences were obtained from SSH library ofZ. jujube’s leaves, and the annotated sequences could be divided into six groups.%枣树具有独特的开花结果特性,为获得枣花发育基因,以金丝4号枣不同发育时期的花蕾和同时期的叶片cDNA互为试验方和驱动方,利用抑制消减杂交技术分别构建了枣花和枣叶抑制消减杂交cDNA文库(SSH文库)。枣花和枣叶SSH文库重组率分别是92.05%和90.26%,插入片段长度均介于200~2000 bp之间,主要集中于1000 bp左右。分别从枣花和枣叶SSH文库中随机挑选1000个阳性克隆进行DNA测序、组装拼接,结果显示枣花SSH文库中获得96条unigene,其中contigs 43个,singletons 53个,96条unigene预测得到73个ORF,经过同源比对分析获得有注释的序列20条,按功能分为7类;枣叶SSH文库中获得86条unigene,其中contigs 45个,singletons 41个,86条unigene预测得到70个ORF,经过同源比对分析获得有23条注释的序列,按功能分为6类。

  14. SMARTer技术构建辣椒黄绿苗突变体叶片全长cDNA文库%Construction of full-length cDNA library of yellow bud mutant leaves in Capsicum annuum L.using SMARTer technique

    Institute of Scientific and Technical Information of China (English)

    马志虎; 孙国胜; 张昌伟; 杨玉霞; 潘跃平

    2013-01-01

    本研究以辣椒黄绿苗嫩叶为材料,提取总RNA,采用LD-PCR技术合成First-strand cDNA和ds cDNA.将分级纯化后的ds cDNA连接到载体pSMART2IFD上,用电穿孔法将重组子转化到大肠杆菌感受态细胞DH5α中,构建辣椒全长cDNA文库.文库质量检测结果显示:原始文库滴度为1.76×106 PFU/ml,重组率为94%,插入片段长度为500~2 000 bp,平均长度为1 170 bp,表明构建的辣椒叶片cDNA文库较为理想,可用于目的基因筛选.%Total RNA was extracted from yellow bud mutant leaves of Capsicum annuum L. , and first-strand cDNA and ds cDNA were synthesized by LD-PCR technology. The purified ds cDNA was connected to vector pSMART2IFD, and the recombinant vectors were transformed into competent Escherichia coli cells DH5a by electroporation to construct full-length cDNA library of Capsicum annuum L_ The library quality test results showed the titer of original library was 1.76× 106PFU/ml, the recombination rate was 94% , and the inserted fragment length was 500-2 000 bp, indicating that the library was ideal for target genes selection.

  15. Human recombinant beta-secretase immobilized enzyme reactor for fast hits' selection and characterization from a virtual screening library.

    Science.gov (United States)

    De Simone, Angela; Mancini, Francesca; Cosconati, Sandro; Marinelli, Luciana; La Pietra, Valeria; Novellino, Ettore; Andrisano, Vincenza

    2013-01-25

    In the present work, a human recombinant BACE1 immobilized enzyme reactor (hrBACE1-IMER) has been applied for the sensitive fast screening of 38 compounds selected through a virtual screening approach. HrBACE1-IMER was inserted into a liquid chromatograph coupled with a fluorescent detector. A fluorogenic peptide substrate (M-2420), containing the β-secretase site of the Swedish mutation of APP, was injected and cleaved in the on-line HPLC-hrBACE1-IMER system, giving rise to the fluorescent product. The compounds of the library were tested for their ability to inhibit BACE1 in the immobilized format and to reduce the area related to the chromatographic peak of the fluorescent enzymatic product. The results were validated in solution by using two different FRET methods. Due to the efficient virtual screening methodology, more than fifty percent of the selected compounds showed a measurable inhibitory activity. One of the most active compound (a bis-indanone derivative) was characterized in terms of IC(50) and K(i) determination on the hrBACE1-IMER. Thus, the hrBACE1-IMER has been confirmed as a valid tool for the throughput screening of different chemical entities with potency lower than 30μM for the fast hits' selection and for mode of action determination.

  16. Towards a universal LC-MS screening procedure - can an LIT LC-MS(n) screening approach and reference library be used on a quadrupole-LIT hybrid instrument?

    Science.gov (United States)

    Wissenbach, Dirk K; Meyer, Markus R; Weber, Armin A; Remane, Daniela; Ewald, Andreas H; Peters, Frank T; Maurer, Hans H

    2012-01-01

    In contrast to libraries with highly reproducible gas chromatography electron ionization mass spectra, current liquid chromatography (LC-MS) libraries are limited to specific instrument types. Therefore, the aim of the study was to prove whether a recently developed linear ion trap (LIT) LC-MS(n) screening approach and reference library can be transferred to an LC-MS/MS system with a quadrupole-LIT hybrid mass analyzer using SmileMS, a sophisticated search algorithm. The LIT reference library was built with MS² and MS³ wideband spectra recorded on a ThermoFisher LXQ LIT with electrospray ionization in positive mode and full-scan data-dependent acquisition (DDA). Collision parameter optimizations, including different scan types and energies, were performed on an Applied Biosystems QTRAP 4000 system using electrospray ionization in positive mode and full-scan DDA. Modified library sets were generated to improve the detection of a compound by the used search algorithm. Additionally, 100 authentic human urine samples were screened by both systems for proof of applicability. In the applicability study, 533 compounds were detected by the LXQ and 477 by the QTRAP system using enhanced product ion scan and a modified database. The presented data showed that the LIT screening approach and reference library could be used successfully on a QTRAP instrument with some limitations. These should be overcome by further optimizations regarding DDA settings for better sensitivity and further library modifications to reduce spectra mismatches.

  17. High content screening of a kinase-focused library reveals compounds broadly-active against dengue viruses.

    Directory of Open Access Journals (Sweden)

    Deu John M Cruz

    Full Text Available Dengue virus is a mosquito-borne flavivirus that has a large impact in global health. It is considered as one of the medically important arboviruses, and developing a preventive or therapeutic solution remains a top priority in the medical and scientific community. Drug discovery programs for potential dengue antivirals have increased dramatically over the last decade, largely in part to the introduction of high-throughput assays. In this study, we have developed an image-based dengue high-throughput/high-content assay (HT/HCA using an innovative computer vision approach to screen a kinase-focused library for anti-dengue compounds. Using this dengue HT/HCA, we identified a group of compounds with a 4-(1-aminoethyl-N-methylthiazol-2-amine as a common core structure that inhibits dengue viral infection in a human liver-derived cell line (Huh-7.5 cells. Compounds CND1201, CND1203 and CND1243 exhibited strong antiviral activities against all four dengue serotypes. Plaque reduction and time-of-addition assays suggests that these compounds interfere with the late stage of viral infection cycle. These findings demonstrate that our image-based dengue HT/HCA is a reliable tool that can be used to screen various chemical libraries for potential dengue antiviral candidates.

  18. 枣结果枝cDNA文库的构建与部分ESTs分析%Construction and Partial ESTs Analysis of a cDNA Library for Fruit-bearing Shoot in Ziziphus jujuba

    Institute of Scientific and Technical Information of China (English)

    孟玉平; 曹秋芬; 孙海峰; 周慧; 张春芬

    2009-01-01

    By using directional cloning, a cDNA Library in the fruit-bearing shoot of Ziziphus jujuba Mill during the early stages of flower bud differentiation was constructed. In 1 388 positive clones, 557 cDNA inserts were obtained. 469 cDNA inserts, length over 500 bp, were selected and sequenced, 390 useful inserts were obtained at last. In these useful sequences,281 ESTs (among them there were 101 repetitive ESTs) were higher similarity with the known genes of CNBI, and 68 ESTs were unknown protein that its sequence had published, another 41 ESTs were unknown sequence (new gene) . The known genes were classified by the classification way of arabidopsis thaliana genes, the result indicated that there were the basal metabolism gene 46 genes,the protein synthesis and transfer gene including 27 genes,the photosyn-thesis gene including 24 genes, the cytoarchitecture gene including 22 genes, the signal transduction gene including 19 genes,the auxesis gene including 19 genes,the resistance adversity gene including 11 genes,the flower development gene including 6 genes, the membrane traffic gene including 4 genes, and the metal transfer gene including 2 genes. The ex-pression of some genes may be relation to the properties of jujube trees's high resistance to the adverse environment, for example,cold resistance,drought resistance,barrenness tolerance and heavy metal tolerance.%用定向克隆法构建了枣(Ziziphus jujuba Mill)生长初期结果枝的部分cDNA文库,获得1 338个阳性克隆,有557个携带cDNA片段,选取469个长度在500 bp以上的进行测序,得到390个有用序列,其中281个ESTs与NCBI中已知功能基因相似性较高(其中重复性ESTs 101个),有68个ESTs是NCBI中有序列注释的未知蛋白,有41个ESTs是NCBI中没有的未知序列(新基因).将已知基因进行功能分类,其中包含有参与基础代谢的基因46个,蛋白质合成与转运基因27个,光合作用基因24个,细胞结构基因22个,信号转导基因19

  19. Molecular cloning of a cDNA related to vernalization(verc203) in winter wheat

    Institute of Scientific and Technical Information of China (English)

    种康; 谭克辉; 黄华梁; 梁厚果

    1995-01-01

    A cDNA clone related to the vernalization in winter wheat(verc203)was harvested from the en-riched cold-induced cDNA library of 10~4 pfu with differential screening.The insert of verc203 in λ gt10 vector wassubcloned into the sites between BamH Ⅰ and Hind Ⅲ in pUC19 plasmid after being amplified with PCR.the analysis of the Northern blotting with a probe of verc203 indicated that the verc203 has a negative signalfor the control and the devernalized mRNA and a positive signal for the vernalized winter wheat and non-vernalized spring wheat at about 2.6 kb.

  20. Cassava cDNA Library Construction: One Tool for Biotechnological Development of the Crop CONSTRUCCIÓN DE UNA LIBRERÍA DE ADNc EN YUCA: UNA HERRAMIENTA PARA EL DESARROLLO BIOTECNOLÓGICO DEL CULTIVO

    Directory of Open Access Journals (Sweden)

    CAROLINA GONZÁLEZ ALMARIO

    el estudio de su función a través de la identificación y la interacción entre proteínas.Cassava is one of the most important crops for global food security and provides food and livelihood for 600 million people in the developing world. It is also good source of starch, with levels between 73.7 y 84.9% of total dry weight in roots (FAO, 2007. Cassava starch can be used in a wide range of industries (textile, cosmetic, nourishing, etc and it has a high potential for the production of biofuel. Cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis (Xam, is one of the most important diseases that affects cassava. This disease can compromise the starch supply not only for bioetanol production but also affect global food security. The long reproductive cycle, high heterozigosity and tetraploid character of cassava are characteristics that have complicated the genetic breeding for this crop. For these reasons new alternatives based on biotechnology are necessary to accelerate its improvement. In the postgenomic era many experiments rely on the availability of transcript sequences for cloning. As these clones usually originate from cDNA libraries, the quality of these libraries is crucial. In this article we report the construction of the first cassava cDNA library employing the Gateway® system. For this, in vitro grown plants were inoculated with the Xam strain CIO151. The expression library shows a high titer of 1 x 10(7 cfu/ml, with inserts ranging between 600 and 1500 bp. The sequence analyses from 14 random clones confirmed that these are expressed genes and showed similarity with previously cloned genes from species related to cassava. This library is an excellent resource for the identification of novel genes and for functional studies through the identification of their interactions with other proteins.

  1. Studying Screen Interactions Long-term: The Library as a Case

    NARCIS (Netherlands)

    Kanis, Marije; Groen, Maarten; Meijs, Wouter; Veenstra, Mettina

    2012-01-01

    This paper presents the design and long-term study of BiebBeep, a large interactive touchscreen that has been developed with the aim to augment the information and social function of a library. BiebBeep displays user-generated and context-relevant content, such as information about local events and

  2. Instant Ligand Libraries. Parallel Synthesis of Monodentate Phosphoramidites and in Situ Screening in Asymmetric Hydrogenation

    NARCIS (Netherlands)

    Lefort, Laurent; Boogers, Jeroen A.F.; Vries, André H.M. de; Vries, Johannes G. de

    2004-01-01

    Chiral phosphoramidites have been identified as excellent ligands for various metal-catalyzed enantioselective transformations. Taking advantage of their easy preparation and modular nature, we designed a fully automated protocol for the parallel preparation of a library of 32 phosphoramidites and i

  3. Expression cloning of different bacterial phosphatase-encoding genes by histochemical screening of genomic libraries onto an indicator medium containing phenolphthalein diphosphate and methyl green.

    Science.gov (United States)

    Riccio, M L; Rossolini, G M; Lombardi, G; Chiesurin, A; Satta, G

    1997-02-01

    A system for expression cloning of bacterial phosphatase-encoding genes has been developed, and its potential has been investigated. The system is based on histochemical screening of bacterial genomic libraries, constructed in an Escherichia coli multicopy plasmid vector, for phosphatase-producing clones using an indicator medium (named TPMG) made of Tryptose-Phosphate agar supplemented with the phosphatase substrate phenolphthalein diphosphate and the stain methyl green. To test the performance of this system, three genomic libraries were constructed from bacterial strains of different species which showed different patterns of phosphatase activity, and were screened using the TPMG medium. Following a partial screening, three different phosphatase-encoding genes (respectively encoding a class A non-specific acid phosphatase, an acid-hexose phosphatase and a non-specific alkaline phosphatase) were shotgun-cloned from the above libraries, indicating that the TPMG-based expression cloning system can be useful for rapid isolation of different bacterial phosphatase-encoding genes.

  4. Direct screening of libraries of yeast clones for alpha-amylase activity on raw starch hydrolysis.

    Science.gov (United States)

    Wong, Dominic W S; Batt, Sarah B; Lee, Charles C; Robertson, George H

    2003-10-01

    High-throughput screening for high-activity barley alpha-amylase mutants expressed in Saccharomyces cerevisiae is hampered by the interference of reducing agents, particularly the glucose used in yeast growth media. The present investigation employed colorimetric and chemiluminescent detection systems that enable direct and rapid screening of activities on raw starch substrate. Active clones could be separated into two groups, based on high total activity or high specific activity.

  5. Discovery of structurally-diverse inhibitor scaffolds by high-throughput screening of a fragment library with dimethylarginine dimethylaminohydrolase.

    Science.gov (United States)

    Linsky, Thomas W; Fast, Walter

    2012-09-15

    Potent and selective inhibitors of the enzyme dimethylarginine dimethylaminohydrolase (DDAH) are useful as molecular probes to better understand cellular regulation of nitric oxide. Inhibitors are also potential therapeutic agents for treatment of pathological states associated with the inappropriate overproduction of nitric oxide, such as septic shock, selected types of cancer, and other conditions. Inhibitors with structures dissimilar to substrate may overcome limitations inherent to substrate analogs. Therefore, to identify structurally-diverse inhibitor scaffolds, high-throughput screening (HTS) of a 4000-member library of fragment-sized molecules was completed using the Pseudomonas aeruginosa DDAH and human DDAH-1 isoforms. Use of a substrate concentration equal to its K(M) value during the primary screen allowed for the detection of inhibitors with different modes of inhibition. A series of validation tests were designed and implemented in the identification of four inhibitors of human DDAH-1 that were unknown prior to the screen. Two inhibitors share a 4-halopyridine scaffold and act as quiescent affinity labels that selectively and covalently modify the active-site Cys residue. Two inhibitors are benzimidazole-like compounds that reversibly and competitively inhibit human DDAH-1 with Ligand Efficiency values ≥0.3 kcal/mol/heavy (non-hydrogen) atom, indicating their suitability for further development. Both inhibitor scaffolds have available sites to derivatize for further optimization. Therefore, use of this fragment-based HTS approach is demonstrated to successfully identify two novel scaffolds for development of DDAH-1 inhibitors.

  6. Synthesis and evaluation of a series of 6-chloro-4-methylumbelliferyl glycosides as fluorogenic reagents for screening metagenomic libraries for glycosidase activity.

    Science.gov (United States)

    Chen, Hong-Ming; Armstrong, Zachary; Hallam, Steven J; Withers, Stephen G

    2016-02-08

    Screening of large enzyme libraries such as those derived from metagenomic sources requires sensitive substrates. Fluorogenic glycosides typically offer the best sensitivity but typically must be used in a stopped format to generate good signal. Use of fluorescent phenols of pKa metagenomic libraries yielded a "hit rate" of 1 in 60. Hits were then readily deconvoluted with the individual substrates in a single plate to identify specific activities within each clone. The use of such a collection of substrates greatly accelerates the screening process.

  7. Cloning and Sequence Analysis of cDNA Encoding MRJP3 of Apis cerana cerana

    Institute of Scientific and Technical Information of China (English)

    SU Song-kun; ZHNEG Huo-qing; CHEN Sheng-lu; ZHONG Bo-xiong; Stefan Albert

    2005-01-01

    By screening the worker (Apis cerana cerana) heads cDNA library using a fragment of the mrjp3 gene ofApis cerana as probe, 120 positive clones were obtained. The clone containing A. cerana cerana MRJP3 (AccMRJP3) cDNA was selected. Based on the sequencing of the inserts of the positive clone, a sequence of AccMRJP3 cDNA which is 1 887 bp long including a poly (A) tail was obtained. The AccMRJP3 cDNA encompassed an open-reading frame (ORF) with 1 779 bp encoding 593 amino acids. The un-translated regions (UTR) of the 5' end and 3' end are 46 bp and 160 bp in length,respectively. Similar to AmMRJP3 and AdMRJP3, the putative AccMRJP3 also has a repetitive region. The comparison of the repetitive region of AccMRJP3, AmMRJP3 and AdMRJP3 shows some differences between them.

  8. Isolation of 24 novel cDNA fragments from microdis—sected human chromosome band

    Institute of Scientific and Technical Information of China (English)

    ZHANGMIN; LONGYU; 等

    1998-01-01

    The strategy of isolating the band0specific expression fragments from a probe pool generated by human chromosome microdissection was reported.A chromosome 14q 24.3 band-specific single copy DNA pool was constructed based on this probe pool.Using total DNA of the pool as probe to hybridize the human marrow cDNA library,68 primary positive clones were selected from 5×105 cDNA clones.Among these primary clones,32 secondary clones were obtained after second-round screening and designed as cFD14-1-32.Finally,24 band-specific expression fragments were identified from these 32 positive clones by DNA hybridization.Those band-specific clones can hybridize to both 14q24.3 DNA and human genomic DNA but cann't hybridize to 17q11-12 DNA,Partial sequences of 13 fragments of them were sequenced and idenfified as novel cDNA sequences,and these sequences were proved to have some homology with known genes in NCBI database.Analysis of expression spectrum of cFD 14-1 suggested that the cDNA fragments thus obtained should be used to isolate the genes can not been cloned in 14q24.3 region.

  9. Isolation and characterization of metalloproteases with a novel domain structure by construction and screening of metagenomic libraries.

    Science.gov (United States)

    Waschkowitz, Tanja; Rockstroh, Stephanie; Daniel, Rolf

    2009-04-01

    Small-insert metagenomic libraries from four samples were constructed by a topoisomerase-based and a T4 DNA ligase-based approach. Direct comparison of both approaches revealed that application of the topoisomerase-based method resulted in a higher number of insert-containing clones per microg of environmental DNA used for cloning and a larger average insert size. Subsequently, the constructed libraries were partially screened for the presence of genes conferring proteolytic activity. The function-driven screen was based on the ability of the library-containing Escherichia coli clones to form halos on skim milk-containing agar plates. The screening of 80,000 E. coli clones yielded four positive clones. Two of the plasmids (pTW2 and pTW3) recovered from positive clones conferred strong proteolytic activity and were studied further. Analysis of the entire insert sequences of pTW2 (28,113 bp) and pTW3 (19,956 bp) suggested that the DNA fragments were derived from members of the genus Xanthomonas. Each of the plasmids harbored one gene (2,589 bp) encoding a metalloprotease (mprA, pTW2; mprB, pTW3). Sequence and biochemical analyses revealed that MprA and MprB are similar extracellular proteases belonging to the M4 family of metallopeptidases (thermolysin-like family). Both enzymes possessed a unique modular structure and consisted of four regions: the signal sequence, the N-terminal proregion, the protease region, and the C-terminal extension. The architecture of the latter region, which was characterized by the presence of two prepeptidase C-terminal domains and one proprotein convertase P domain, is novel for bacterial metalloproteases. Studies with derivatives of MprA and MprB revealed that the C-terminal extension is not essential for protease activity. The optimum pH and temperature of both proteases were 8.0 and 65 degrees C, respectively, when casein was used as substrate.

  10. Functional-based screening methods for lipases, esterases, and phospholipases in metagenomic libraries.

    Science.gov (United States)

    Reyes-Duarte, Dolores; Ferrer, Manuel; García-Arellano, Humberto

    2012-01-01

    The use of metagenomic techniques for enzyme discovery constitutes a powerful approach. Functional screens, in contrast to sequence homology search, enable us to select enzymes based on their activity. It is noteworthy that they additionally guarantee the identification of genes coding for enzymes that exhibited no sequence similarity to known counterparts from public databases and that even do not match any putative catalytic residues, involved in the selected catalytic function. Therefore, this strategy not only provides new enzymes for new biotechnological applications, but also allows functional assignment of many proteins, found in abundance in the databases, currently designated as "hypothetical" or "conserved hypothetical" proteins. In the past decade, there has been an exponential increase in the design of functional screening programmes, the majority of them established for hydrolases and oxidoreductases. Here, functional screening methods that guarantee the greatest enzyme diversity, for mining esterases and lipases, are described.

  11. cDNA expression library screening and identification of two novel antigens, ubiquitin and receptor for activated C kinase (RACK) homologue, of the fish parasite Trypanosoma carassii

    NARCIS (Netherlands)

    Ruszczyk, A.; Joerink, M.; Guldenaar, C.; Hermsen, G.J.; Savelkoul, H.F.J.; Wiegertjes, G.F.

    2008-01-01

    Trypanosoma carassii is a kinetoplastid parasite infecting cyprinid fish with a high prevalence in nature. Antibodies have been shown to play a protective role in the immune response against this parasite in common carp, Cyprinus carpio. To identify immunogenic and putative protective T. carassii an

  12. 基于PCR技术筛选cDNA和genome文库方法的改进%Improvement on PCR-based cDNA and Genomic Library Screening

    Institute of Scientific and Technical Information of China (English)

    程旭东; 董玲丽; 凌宏清

    2004-01-01

    提出一种改进的基于PCR技术的cDNA和genome文库筛选新方法.该方法利用PCR手段逐步排除文库中的非阳性克隆组分,提高阳性克隆所占比重,最后得到含有一定数量阳性单克隆的最小克隆群体用于直接挑选单个阳性克隆.在筛选cDNA文库时则增加了一个将噬菌体文库转化成质粒文库的步骤.该方法既保留了常规PCR文库筛选方法的灵敏、快捷和经济的特点,又弥补了其筛选周期相对较长、工作量大,以及随着循环数的增加和提取DNA的难度加大,阳性克隆容易丢失等缺陷,尤其在用于筛选cDNA文库时更是免除了繁琐的滴度、侵染和洗脱过程,极大地提高了筛选的成功率.

  13. Improvement on phage cDNA library screening%噬菌体cDNA文库筛选方法的改良

    Institute of Scientific and Technical Information of China (English)

    尚毅; 马璐琳; 亓增军; 刘大钧; 王秀娥

    2010-01-01

    cDNA文库的构建和简便、快速的筛选是获得全长基因的重要途径,基于PCR的筛库方法具有快捷、灵敏的特点.研究改进了基于PCR的噬菌体cDNA文库筛选方法,用液体分装的方法,替代了文库筛选的关键步骤--涂板分区,省去了噬菌体文库铺平板、浸粢、培养、划块洗脱的操作过程,使筛库的工作量减少,进一步提高了筛选速度和获得阳性克隆的效率.

  14. A new implementation of high-throughput five-dimensional clone pooling strategy for BAC library screening

    Directory of Open Access Journals (Sweden)

    Deal Karin R

    2010-12-01

    Full Text Available Abstract Background A five-dimensional (5-D clone pooling strategy for screening of bacterial artificial chromosome (BAC clones with molecular markers utilizing highly-parallel Illumina GoldenGate assays and PCR facilitates high-throughput BAC clone and BAC contig anchoring on a genetic map. However, this strategy occasionally needs manual PCR to deconvolute pools and identify truly positive clones. Results A new implementation is reported here for our previously reported clone pooling strategy. Row and column pools of BAC clones are divided into sub-pools with 1~2× genome coverage. All BAC pools are screened with Illumina's GoldenGate assay and the BAC pools are deconvoluted to identify individual positive clones. Putative positive BAC clones are then further analyzed to find positive clones on the basis of them being neighbours in a contig. An exhaustive search or brute force algorithm was designed for this deconvolution and integrated into a newly developed software tool, FPCBrowser, for analyzing clone pooling data. This algorithm was used with empirical data for 55 Illumina GoldenGate SNP assays detecting SNP markers mapped on Aegilops tauschii chromosome 2D and Ae. tauschii contig maps. Clones in single contigs were successfully assigned to 48 (87% specific SNP markers on the map with 91% precision. Conclusion A new implementation of 5-D BAC clone pooling strategy employing both GoldenGate assay screening and assembled BAC contigs is shown here to be a high-throughput, low cost, rapid, and feasible approach to screening BAC libraries and anchoring BAC clones and contigs on genetic maps. The software FPCBrowser with the integrated clone deconvolution algorithm has been developed and is downloadable at http://avena.pw.usda.gov/wheatD/fpcbrowser.shtml.

  15. Electronic cDNA library screening directs the full-length cDNA cloning of a gene%"电子"cDNA文库筛选指导基因的全长cDNA克隆

    Institute of Scientific and Technical Information of China (English)

    李刚; 胡迎春; 张开泰; 吴德昌

    2000-01-01

    "电子"cDNA文库筛选主要是指通过采用生物信息学的方法延伸表达序列标签(EST)序列,以获得基因的部分乃至全长cDNA序列,避免或部分避免构建与筛选cDNA文库等烦琐的实验室工作.该方法具体体现了EST数据库的迅速扩张已导致识别与克隆新基因的策略发生革命性的变化.EST序列ZA73为本实验室克隆到的可能参与辐射致气管上皮细胞恶性转化过程的基因片段,本研究采用"电子"cDNA文库筛选的方法对其可能的全基因序列作了预测.

  16. Epigenetic Library Screen Identifies Abexinostat as Novel Regulator of Adipocytic and Osteoblastic Differentiation of Human Skeletal (Mesenchymal) Stem Cells

    DEFF Research Database (Denmark)

    Ali; Hamam; Alfayez;

    2016-01-01

    The epigenetic mechanisms promoting lineage-specific commitment of human skeletal (mesenchymal or stromal) stem cells (hMSCs) into adipocytes or osteoblasts are still not fully understood. Herein, we performed an epigenetic library functional screen and identified several novel compounds, including...... abexinostat, which promoted adipocytic and osteoblastic differentiation of hMSCs. Using gene expression microarrays, chromatin immunoprecipitation for H3K9Ac combined with high-throughput DNA sequencing (ChIP-seq), and bioinformatics, we identified several key genes involved in regulating stem cell...... or stromal) stem cells (hMSCs). These data provide new insight into the understanding of the relationship between the epigenetic effect of histone deacetylase inhibitors, transcription factors, and differentiation pathways controlling adipocyte and osteoblast differentiation of hMSCs. Manipulating...

  17. Erkitinib, a novel EGFR tyrosine kinase inhibitor screened using a ProteoChip system from a phytochemical library

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eung-Yoon; Choi, Young-Jin [Biochip Research Center, Hoseo University, Asan 336-795 (Korea, Republic of); Innopharmascreen, Inc., Asan 336-795 (Korea, Republic of); Park, Chan-Won [Biochip Research Center, Hoseo University, Asan 336-795 (Korea, Republic of); Dept. of Biological Science, Hoseo University, Asan 336-795 (Korea, Republic of); Kang, In-Cheol, E-mail: ickang@hoseo.edu [Biochip Research Center, Hoseo University, Asan 336-795 (Korea, Republic of); Dept. of Biological Science, Hoseo University, Asan 336-795 (Korea, Republic of); Innopharmascreen, Inc., Asan 336-795 (Korea, Republic of)

    2009-11-20

    Receptor tyrosine kinases (PTKs) play key roles in the pathogenesis of numerous human diseases, including cancer. Therefore PTK inhibitors are currently under intensive investigation as potential drug candidates. Herein, we report on a ProteoChip-based screening of an epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitor, Erkitinibs, from phytochemical libraries. PLC-{gamma}-1 was used as a substrate immobilized on a ProteoChip and incubated with an EGFR kinase to phosphorylate tyrosine residues of the substrate, followed by a fluorescence detection of the substrate recognized by a phospho-specific monoclonal antibody. Erkitinibs inhibited HeLa cell proliferation in a dose-dependent manner. In conclusion, these data suggest that Erkitinibs can be a specific inhibitor of an EGFR kinase and can be further developed as a potent anti-tumor agent.

  18. cDNA cloning of human myeloperoxidase: decrease in myeloperoxidase mRNA upon induction of HL-60 cells

    Energy Technology Data Exchange (ETDEWEB)

    Weil, S.C.; Rosner, G.L.; Reid, M.S.; Chisholm, R.L.; Farber, N.M.; Spitznagel, J.K.; Swanson, M.S.

    1987-04-01

    Myeloperoxidase (MPO), the most abundant neutrophil protein, is a bacteriocidal component of the primary granules and a critical marker in distinguishing acute myelogenous leukemia from acute lymphoid leukemia. A cDNA clone for human MPO was isolated by immunologic screening of human hematopoietic lambdagt11 expression vector libraries with specific anti-MPO antibody. The identity of the cDNA clone was confirmed by finding that (i) epitope-selected antibody against this clone recognizes purified MPO and MPO in human promyelocytic (HL-60) cell lysates by immunoblot analysis, and that (ii) hybrid section of HL-60 mRNA with this cDNA clone and translation in vitro results in the synthesis of an 80-kDa protein recognized by the anti-MPO antiserum. RNA blot analysis with this MPO cDNA clone detects hybridization to two polyadenylylated transcripts of approx. = 3.6 and approx. = 2.9 kilobases in HL-60 cells. No hybridization is detected to human placenta mRNA. Upon induction of HL-60 cells to differentiate by incubation for 4 days with dimethyl sulfoxide, a drastic decrease in the hybridization intensity of these two bands is seen. This is consistent with previous data suggesting a decrease in MPO synthesis upon such induction of these cells. The MPO cDNA should be useful for further molecular and genetic characterization of MPO and its expression and biosynthesis in normal and leukemic granulocytic differentiation.

  19. Chemical library screening for WNK signalling inhibitors using fluorescence correlation spectroscopy.

    Science.gov (United States)

    Mori, Takayasu; Kikuchi, Eriko; Watanabe, Yuko; Fujii, Shinya; Ishigami-Yuasa, Mari; Kagechika, Hiroyuki; Sohara, Eisei; Rai, Tatemitsu; Sasaki, Sei; Uchida, Shinichi

    2013-11-01

    WNKs (with-no-lysine kinases) are the causative genes of a hereditary hypertensive disease, PHAII (pseudohypoaldosteronism type II), and form a signal cascade with OSR1 (oxidative stress-responsive 1)/SPAK (STE20/SPS1-related proline/alanine-rich protein kinase) and Slc12a (solute carrier family 12) transporters. We have shown that this signal cascade regulates blood pressure by controlling vascular tone as well as renal NaCl excretion. Therefore agents that inhibit this signal cascade could be a new class of antihypertensive drugs. Since the binding of WNK to OSR1/SPAK kinases was postulated to be important for signal transduction, we sought to discover inhibitors of WNK/SPAK binding by screening chemical compounds that disrupt the binding. For this purpose, we developed a high-throughput screening method using fluorescent correlation spectroscopy. As a result of screening 17000 compounds, we discovered two novel compounds that reproducibly disrupted the binding of WNK to SPAK. Both compounds mediated dose-dependent inhibition of hypotonicity-induced activation of WNK, namely the phosphorylation of SPAK and its downstream transporters NKCC1 (Na/K/Cl cotransporter 1) and NCC (NaCl cotransporter) in cultured cell lines. The two compounds could be the promising seeds of new types of antihypertensive drugs, and the method that we developed could be applied as a general screening method to identify compounds that disrupt the binding of two molecules.

  20. Identification of three classes of heteroaromatic compounds with activity against intracellular Trypanosoma cruzi by chemical library screening.

    Directory of Open Access Journals (Sweden)

    Esther Bettiol

    Full Text Available The development of new drugs against Chagas disease is a priority since the currently available medicines have toxic effects, partial efficacy and are targeted against the acute phase of disease. At present, there is no drug to treat the chronic stage. In this study, we have optimized a whole cell-based assay for high throughput screening of compounds that inhibit infection of mammalian cells by Trypanosoma cruzi trypomastigotes. A 2000-compound chemical library was screened using a recombinant T. cruzi (Tulahuen strain expressing beta-galactosidase. Three hits were selected for their high activity against T. cruzi and low toxicity to host cells in vitro: PCH1, NT1 and CX1 (IC(50: 54, 190 and 23 nM, respectively. Each of these three compounds presents a different mechanism of action on intracellular proliferation of T. cruzi amastigotes. CX1 shows strong trypanocidal activity, an essential characteristic for the development of drugs against the chronic stage of Chagas disease where parasites are found intracellular in a quiescent stage. NT1 has a trypanostatic effect, while PCH1 affects parasite division. The three compounds also show high activity against intracellular T. cruzi from the Y strain and against the related kinetoplastid species Leishmania major and L. amazonensis. Characterization of the anti-T. cruzi activity of molecules chemically related to the three library hits allowed the selection of two compounds with IC(50 values of 2 nM (PCH6 and CX2. These values are approximately 100 times lower than those of the medicines used in patients against T. cruzi. These results provide new candidate molecules for the development of treatments against Chagas disease and leishmaniasis.

  1. Generation of chicken Z-chromosome painting probes by microdissection for screening large-insert genomic libraries.

    Science.gov (United States)

    Zimmer, R; King, W A; Verrinder Gibbins, A M

    1997-01-01

    A strategy for rapid generation of chicken sex chromosome-Z painting probes has been developed using microdissection. Whole chromosome painting probes (WCPs) were prepared from 10-15 copies of mitotic metaphase chicken Z chromosomes. The microisolated chromosomes were subjected to PEG/proteinase K treatment in a collection drop to release DNA, which was then amplified using a degenerate oligonucleotide-primed shuttle PCR (DOP-Shuttle-PCR) strategy. Size distributions of the PCR products were analyzed by agarose gel electrophoresis and smears of DNA were revealed that ranged in size from 200-800 bp, without any evidence of preferential amplification. Both specificity and complexity of the probes have been analyzed by Southern blot and fluorescence in situ hybridization (FISH). Non-specific hybridization was efficiently blocked by using chicken competitor DNA. Analysis of the WCPs produced shows that collectively they provide uniform hybridization signals along the entire length of the chicken Z chromosome. To demonstrate one possible application of these complex probes, we screened a large-insert bacterial artificial chromosome (BAC) chicken genomic library to select Z chromosome-specific clones. To address specificity of the selected clones and to physically map them to the Z chromosome, FISH analysis was used. Of the 3 clones initially tested, one clone (C3) carrying a 250-kb insert mapped to the distal portion of the short arm of the chicken Z chromosome. Therefore, this technique has provided appropriate probes for screening large-insert genomic libraries. Further application of these probes includes the analysis of chromosome rearrangements, studies of cases of heteroploidy involving the Z chromosome, positional cloning of Z-linked genes and studies on mechanisms of sex-chromosome evolution in birds.

  2. Genetic screening of new genes responsible for cellular adaptation to hypoxia using a genome-wide shRNA library.

    Science.gov (United States)

    Yoshino, Seiko; Hara, Toshiro; Weng, Jane S; Takahashi, Yuka; Seiki, Motoharu; Sakamoto, Takeharu

    2012-01-01

    Oxygen is a vital requirement for multi-cellular organisms to generate energy and cells have developed multiple compensatory mechanisms to adapt to stressful hypoxic conditions. Such adaptive mechanisms are intricately interconnected with other signaling pathways that regulate cellular functions such as cell growth. However, our understanding of the overall system governing the cellular response to the availability of oxygen remains limited. To identify new genes involved in the response to hypoxic stress, we have performed a genome-wide gene knockdown analysis in human lung carcinoma PC8 cells using an shRNA library carried by a lentiviral vector. The knockdown analysis was performed under both normoxic and hypoxic conditions to identify shRNA sequences enriched or lost in the resulting selected cell populations. Consequently, we identified 56 candidate genes that might contribute to the cellular response to hypoxia. Subsequent individual knockdown of each gene demonstrated that 13 of these have a significant effect upon oxygen-sensitive cell growth. The identification of BCL2L1, which encodes a Bcl-2 family protein that plays a role in cell survival by preventing apoptosis, validates the successful design of our screen. The other selected genes have not previously been directly implicated in the cellular response to hypoxia. Interestingly, hypoxia did not directly enhance the expression of any of the identified genes, suggesting that we have identified a new class of genes that have been missed by conventional gene expression analyses to identify hypoxia response genes. Thus, our genetic screening method using a genome-wide shRNA library and the newly-identified genes represent useful tools to analyze the cellular systems that respond to hypoxic stress.

  3. Crystal structure of importin-{alpha} complexed with a classic nuclear localization sequence obtained by oriented peptide library screening

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, A.A.S.; Fontes, M.R.M. [UNESP, Universidade Estadual Paulista, Botucatu, SP (Brazil); Yang, S.N.Y. [University of Melbourne, Melbourne (Australia); Harris, J.M. [Queensland University of Technology, Brisbane (Australia); Jans, D.A. [Monash University, Clayton (Australia); Kobe, B. [University of Queensland, Brisbane, QU (Australia)

    2012-07-01

    Full text: Importin-{alpha} (Imp{alpha}) plays a role in the classical nuclear import pathway, binding to cargo proteins with activities in the nucleus. Different Imp{alpha} paralogs responsible for specific cargos can be found in a single organism. The cargos contain nuclear localization sequences (NLSs), which are characterized by one or two clusters of basic amino acids (monopartite and bipartite NLSs, respectively). In this work we present the crystal structure of Imp{alpha} from M. musculus (residues 70-529, lacking the auto inhibitory domain) bound to a NLS peptide (pepTM). The peptide corresponds to the optimal sequence obtained by an oriented peptide library experiment designed to probe the specificity of the major NLS binding site. The peptide library used five degenerate positions and identified the sequence KKKRR as the optimal sequence for binding to this site for mouse Imp{alpha} (70-529). The protein was obtained using an E. coli expression system and purified by affinity chromatography followed by an ion exchange chromatography. A single crystal of Imp{alpha} -pepTM complex was grown by the hanging drop method. The data were collected using the Synchrotron Radiation Source LNLS, Brazil and processed to 2.3. Molecular replacement techniques were used to determine the crystal structure. Electron density corresponding to the peptide was present in both major and minor binding sites The peptide is bound to Imp{alpha} similar as the simian virus 40 (SV40) large tumour (T)-antigen NLS. Binding assays confirmed that the peptide bound to Imp{alpha} with low nM affinities. This is the first time that structural information has been linked to an oriented peptide library screening approach for importin-{alpha}; the results will contribute to understanding of the sequence determinants of classical NLSs, and may help identify as yet unidentified classical NLSs in novel proteins. (author)

  4. Identification of a Potent Allosteric Inhibitor of Human Protein Kinase CK2 by Bacterial Surface Display Library Screening.

    Science.gov (United States)

    Nienberg, Christian; Garmann, Claudia; Gratz, Andreas; Bollacke, Andre; Götz, Claudia; Jose, Joachim

    2017-01-05

    Human protein kinase CK2 has emerged as promising target for the treatment of neoplastic diseases. The vast majority of kinase inhibitors known today target the ATP binding site, which is highly conserved among kinases and hence leads to limited selectivity. In order to identify non-ATP competitive inhibitors, a 12-mer peptide library of 6 × 10⁵ variants was displayed on the surface of E. coli by autodisplay. Screening of this peptide library on variants with affinity to CK2 was performed by fluorophore-conjugated CK2 and subsequent flow cytometry. Single cell sorting of CK2-bound E. coli yielded new peptide variants, which were tested on inhibition of CK2 by a CE-based assay. Peptide B2 (DCRGLIVMIKLH) was the most potent inhibitor of both, CK2 holoenzyme and the catalytic CK2α subunit (IC50 = 0.8 µM). Using different ATP concentrations and different substrate concentrations for IC50 determination, B2 was shown to be neither ATP- nor substrate competitive. By microscale thermophoresis (MST) the KD value of B2 with CK2α was determined to be 2.16 µM, whereas no binding of B2 to CK2β-subunit was detectable. To our surprise, besides inhibition of enzymatic activity, B2 also disturbed the inte