Literatura académica sobre el tema "Sequence similarity analysis"
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Artículos de revistas sobre el tema "Sequence similarity analysis"
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Wei, Dan, Qingshan Jiang y Sheng Li. "A New Approach for DNA Sequence Similarity Analysis based on Triplets of Nucleic Acid Bases". International Journal of Nanotechnology and Molecular Computation 2, n.º 4 (octubre de 2010): 1–11. http://dx.doi.org/10.4018/978-1-60960-064-8.ch006.
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Similarity analysis of DNA sequences is a fundamental research area in Bioinformatics. The characteristic distribution of L-tuple, which is the tuple of length L, reflects the valuable information contained in a biological sequence and thus may be used in DNA sequence similarity analysis. However, similarity analysis based on characteristic distribution of L-tuple is not effective for the comparison of highly conservative sequences. In this paper, a new similarity measurement approach based on Triplets of Nucleic Acid Bases (TNAB) is introduced for DNA sequence similarity analysis. The new approach characterizes both the content feature and position feature of a DNA sequence using the frequency and position of occurrence of TNAB in the sequence. The experimental results show that the approach based on TNAB is effective for analysing DNA sequence similarity.
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Li, Hongliang y Bin Liu. "BioSeq-Diabolo: Biological sequence similarity analysis using Diabolo". PLOS Computational Biology 19, n.º 6 (20 de junio de 2023): e1011214. http://dx.doi.org/10.1371/journal.pcbi.1011214.
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As the key for biological sequence structure and function prediction, disease diagnosis and treatment, biological sequence similarity analysis has attracted more and more attentions. However, the exiting computational methods failed to accurately analyse the biological sequence similarities because of the various data types (DNA, RNA, protein, disease, etc) and their low sequence similarities (remote homology). Therefore, new concepts and techniques are desired to solve this challenging problem. Biological sequences (DNA, RNA and protein sequences) can be considered as the sentences of “the book of life”, and their similarities can be considered as the biological language semantics (BLS). In this study, we are seeking the semantics analysis techniques derived from the natural language processing (NLP) to comprehensively and accurately analyse the biological sequence similarities. 27 semantics analysis methods derived from NLP were introduced to analyse biological sequence similarities, bringing new concepts and techniques to biological sequence similarity analysis. Experimental results show that these semantics analysis methods are able to facilitate the development of protein remote homology detection, circRNA-disease associations identification and protein function annotation, achieving better performance than the other state-of-the-art predictors in the related fields. Based on these semantics analysis methods, a platform called BioSeq-Diabolo has been constructed, which is named after a popular traditional sport in China. The users only need to input the embeddings of the biological sequence data. BioSeq-Diabolo will intelligently identify the task, and then accurately analyse the biological sequence similarities based on biological language semantics. BioSeq-Diabolo will integrate different biological sequence similarities in a supervised manner by using Learning to Rank (LTR), and the performance of the constructed methods will be evaluated and analysed so as to recommend the best methods for the users. The web server and stand-alone package of BioSeq-Diabolo can be accessed at http://bliulab.net/BioSeq-Diabolo/server/.
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de Oliveira Martins, Leonardo, Alison E. Mather y Andrew J. Page. "Scalable neighbour search and alignment with uvaia". PeerJ 12 (6 de marzo de 2024): e16890. http://dx.doi.org/10.7717/peerj.16890.
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Despite millions of SARS-CoV-2 genomes being sequenced and shared globally, manipulating such data sets is still challenging, especially selecting sequences for focused phylogenetic analysis. We present a novel method, uvaia, which is based on partial and exact sequence similarity for quickly extracting database sequences similar to query sequences of interest. Many SARS-CoV-2 phylogenetic analyses rely on very low numbers of ambiguous sites as a measure of quality since ambiguous sites do not contribute to single nucleotide polymorphism (SNP) differences. Uvaia overcomes this limitation by using measures of sequence similarity which consider partially ambiguous sites, allowing for more ambiguous sequences to be included in the analysis if needed. Such fine-grained definition of similarity allows not only for better phylogenetic analyses, but could also lead to improved classification and biogeographical inferences. Uvaia works natively with compressed files, can use multiple cores and efficiently utilises memory, being able to analyse large data sets on a standard desktop.
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Van Reenen, C. A., W. H. Van Zyl y L. M. T. Dicks. "Expression of the Immunity Protein of Plantaricin 423, Produced by Lactobacillus plantarum 423, and Analysis of the Plasmid Encoding the Bacteriocin". Applied and Environmental Microbiology 72, n.º 12 (20 de octubre de 2006): 7644–51. http://dx.doi.org/10.1128/aem.01428-06.
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ABSTRACT Plantaricin 423 is a class IIa bacteriocin produced by Lactobacillus plantarum isolated from sorghum beer. It has been previously determined that plantaricin 423 is encoded by a plasmid designated pPLA4, which is now completely sequenced. The plantaricin 423 operon shares high sequence similarity with the operons of coagulin, pediocin PA-1, and pediocin AcH, with small differences in the DNA sequence encoding the mature bacteriocin peptide and the immunity protein. Apart from the bacteriocin operon, no significant sequence similarity could be detected between the DNA or translated sequence of pPLA4 and the available DNA or translated sequences of the plasmids encoding pediocin AcH, pediocin PA-1, and coagulin, possibly indicating a different origin. In addition to the bacteriocin operon, sequence analysis of pPLA4 revealed the presence of two open reading frames (ORFs). ORF1 encodes a putative mobilization (Mob) protein that is homologous to the pMV158 superfamily of mobilization proteins. Highest sequence similarity occurred between this protein and the Mob protein of L. plantarum NCDO 1088. ORF2 encodes a putative replication protein that revealed low sequence similarity to replication proteins of plasmids pLME300 from Lactobacillus fermentum and pYIT356 from Lactobacillus casei. The immunity protein of plantaricin 423 contains 109 amino acids. Although plantaricin 423 shares high sequence similarity with the pediocin PA-1 operon, no cross-reactivity was recorded between the immunity proteins of plantaricin 423 and pediocin PA-1.
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Pacheco, Richard C., Jonas Moraes-Filho, Arlei Marcili, Leonardo J. Richtzenhain, Matias P. J. Szabó, Márcia H. B. Catroxo, Donald H. Bouyer y Marcelo B. Labruna. "Rickettsia monteiroi sp. nov., Infecting the Tick Amblyomma incisum in Brazil". Applied and Environmental Microbiology 77, n.º 15 (17 de junio de 2011): 5207–11. http://dx.doi.org/10.1128/aem.05166-11.
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ABSTRACTFree-living adultAmblyomma incisumticks were collected in an Atlantic rainforest area at Intervales State Park, State of São Paulo, Brazil. From anA. incisumspecimen, rickettsiae were successfully isolated in Vero cell culture by the shell vial technique. Rickettsial isolation was confirmed by optical microscopy, transmission electron microscopy, and PCRs targeting portions of the rickettsial genesgltA,htrA,rrs, andsca1on infected cells. Fragments of 1,089, 457, 1,362, and 443 nucleotides of thegltA,htrA,rrs, andsca1genes, respectively, were sequenced. By BLAST analysis, the partial sequence ofrrsof theA. incisumrickettsial isolate was closest to the corresponding sequence ofRickettsia bellii(99.1% similarity). ThegltApartial sequence was closest to the corresponding sequences of “CandidatusRickettsia tarasevichiae” (96.1% similarity) andRickettsia canadensis(95.8% similarity). ThehtrApartial sequence was closest to the corresponding sequence ofR. canadensis(89.8% similarity). Thesca1partial sequence was closest to the corresponding sequence ofR. canadensis(95.2% similarity). Since our rickettsial isolate was genetically distinct from otherRickettsiaspecies, we propose a new species designatedRickettsia monteiroisp. nov. Phylogenetic analyses indicated thatR. monteiroibelongs to the canadensis group within the genusRickettsia, together with the speciesR. canadensisand “CandidatusR. tarasevichiae”. Little or no antibody cross-reaction was observed between sera ofR. monteiroi-inoculated guinea pigs andR. bellii-,Rickettsia rickettsii-, orR. canadensis-inoculated guinea pigs.
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Smallwood, M., J. N. Keen y D. J. Bowles. "Purification and partial sequence analysis of plant annexins". Biochemical Journal 270, n.º 1 (15 de agosto de 1990): 157–61. http://dx.doi.org/10.1042/bj2700157.
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A fractionation procedure for annexins involving Ca2(+)-dependent binding to exogenous phospholipid was applied to tomato suspension culture cells. Two polypeptides (34 kDa and 35.5 kDa) were purified and separated from each other and from contaminant pectic polysaccharide by ion-exchange chromatography. After proteolytic digestion of SDS/PAGE-purified products, N-terminal sequencing of the peptide fragments revealed substantial similarity to sequences of known members of the annexin family characterized from a range of animal tissues. In particular, sequence similarity to the 70-amino acid-residue repeat region found in all annexins sequenced to date was present in both of the plant proteins. The data are discussed within the context of annexin involvement in Ca2(+)-mediated events in higher plants.
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Györgyey, János, Danièle Vaubert, José I. Jiménez-Zurdo, Celine Charon, Liliane Troussard, Ádám Kondorosi y Éva Kondorosi. "Analysis of Medicago truncatula Nodule Expressed Sequence Tags". Molecular Plant-Microbe Interactions® 13, n.º 1 (enero de 2000): 62–71. http://dx.doi.org/10.1094/mpmi.2000.13.1.62.
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Systematic sequencing of expressed sequence tags (ESTs) can give a global picture of the assembly of genes involved in the development and function of organs. Indeterminate nodules representing different stages of the developmental program are especially suited to the study of organogenesis. With the vector λHybriZAP, a cDNA library was constructed from emerging nodules of Medicago truncatula induced by Sinorhizobium meliloti. The 5′ ends of 389 cDNA clones were sequenced, then these ESTs were analyzed both by sequence homology search and by studying their expression in roots and nodules. Two hundred fifty-six ESTs exhibited significant similarities to characterized data base entries and 40 of them represented 26 nodulin genes, while 133 had no similarity to sequences with known function. Only 60 out of the 389 cDNA clones corresponded to previously submitted M. truncatula EST sequences. For 117 cDNAs, reverse Northern (RNA) hybridization with root and nodule RNA probes revealed enhanced expression in the nodule, 48 clones are likely to code for novel nodulins, 33 cDNAs are clones of already known nodulin genes, and 36 clones exhibit similarity to other characterized genes. Thus, systematic analysis of the EST sequences and their expression patterns is a powerful way to identify nodule-specific and nodulation-related genes.
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Xu, Fuyu y Kate Beard. "A Unifying Framework for Analysis of Spatial-Temporal Event Sequence Similarity and Its Applications". ISPRS International Journal of Geo-Information 10, n.º 9 (9 de septiembre de 2021): 594. http://dx.doi.org/10.3390/ijgi10090594.
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Measures of similarity or differences between data objects are applied frequently in geography, biology, computer science, linguistics, logic, business analytics, and statistics, among other fields. This work focuses on event sequence similarity among event sequences extracted from time series observed at spatially deployed monitoring locations with the aim of enhancing the understanding of process similarity over time and geospatial locations. We present a framework for a novel matrix-based spatiotemporal event sequence representation that unifies punctual and interval-based representation of events. This unified representation of spatiotemporal event sequences (STES) supports different event data types and provides support for data mining and sequence classification and clustering. The similarity measure is based on the Jaccard index with temporal order constraints and accommodates different event data types. The approach is demonstrated through simulated data examples and the performance of the similarity measures is evaluated with a k-nearest neighbor algorithm (k-NN) classification test on synthetic datasets. As a case study, we demonstrate the use of these similarity measures in a spatiotemporal analysis of event sequences extracted from space time series of a water quality monitoring system.
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Nikhila, K. S. y Vrinda V. Nair. "Protein Sequence Similarity Analysis Using Computational Techniques". Materials Today: Proceedings 5, n.º 1 (2018): 724–31. http://dx.doi.org/10.1016/j.matpr.2017.11.139.
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Hark Gan, Hin, Rebecca A. Perlow, Sharmili Roy, Joy Ko, Min Wu, Jing Huang, Shixiang Yan et al. "Analysis of Protein Sequence/Structure Similarity Relationships". Biophysical Journal 83, n.º 5 (noviembre de 2002): 2781–91. http://dx.doi.org/10.1016/s0006-3495(02)75287-9.
Texto completoTesis sobre el tema "Sequence similarity analysis"
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Joseph, Arokiya Louis Monica. "Sequence Similarity Search portal". CSUSB ScholarWorks, 2007. https://scholarworks.lib.csusb.edu/etd-project/3124.
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This project brings the bioinformatics community a new development concept in which users can access all data and applications hosted in the main research centers as if they were installed on their local machines, providing seamless integration between disparate services. The project moves to integrate the sequence similarity searching at EBI and NCBI by using web services. It also intends to allow molecular biologists to save their searches and act as a log book for their sequence similarity searches. The project will also allow the biologists to share their sequences and results with others.
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Chen, Zhuo. "Smart Sequence Similarity Search (S⁴) system". CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2458.
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Sequence similarity searching is commonly used to help clarify the biochemical and physiological features of newly discovered genes or proteins. An efficient similarity search relies on the choice of tools and their associated subprograms and numerous parameter settings. To assist researchers in selecting optimal programs and parameter settings for efficient sequence similarity searches, the web-based expert system, Smart Sequence Similarity Search (S4) was developed.
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Mendoza, Leon Jesus Alexis. "Analysis of DNA sequence similarity within organisms causing New World leishmaniasis". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386206.
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Batra, Sushil Baker Erich J. Lee Myeongwoo. "Identification of phenotypes in Caenorabhditis elegans on the basis of sequence similarity". Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5325.
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Ozturk, Ozgur. "Feature extraction and similarity-based analysis for proteome and genome databases". The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1190138805.
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Mitas̃iūnaite, Ieva. "Mining string data under similarity and soft-frequency constraints : application to promoter sequence analysis". Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0036/these.pdf.
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Nous étudions l'extraction de motifs sous contraintes dans des collections de chaînes de caractères et le développement de solveurs complets et génériques pour l'extraction de tous les motifs satisfaisant une combinaison de contraintes primitives. Un solveur comme FAVST permet d'optimiser des conjonctions de contraintes dites monotones et/ou anti-monotones (e. G. , des contraintes de fréquence maximale et minimale). Nous avons voulu compléter ce type d'outil en traitant des contraintes pour la découverte de motifs tolérants aux exceptions. Nous proposons différentes définitions des occurrences approchées et l'exploitation de contraintes de fréquence approximative. Ceci nous conduit à spécifier des contraintes difficiles (e. G. , pour l'expression de la similarité) comme des conjonctions de primitives monotones et anti-monotones optimisées par notre solveur MARGUERITE. Soucieux de sa mise en ?uvre dans des processus de découverte de connaissances à partir de données, nous avons analysé le réglage des paramètres d'extraction (e. G. , quel seuil choisir pour les fréquences). Nous proposons une méthode originale pour estimer le nombre de motifs qui satisfont une contrainte au moyen d'un échantillonnage de l'espace des motifs. Nous avons également étudié l'identification des paramètres les plus stringents pour fournir des motifs qui ne sont probablement pas de faux positifs. Ces contributions ont été appliquées à l'analyse des séquences promotrices des gènes. En étroite collaboration avec une équipe de biologistes du CGMC, nous avons pu identifier des sites de fixation putatifs de facteurs transcription impliqués dans le processus de différenciation cellulaireAn inductive database is a database that contains not only data but also patterns. Inductive databases are designed to support the KDD process. Recent advances in inductive databases research have given rise to a generic solvers capable of solving inductive queries that are arbitrary Boolean combinations of anti-monotonic and monotonic constraints. They are designed to mine different types of pattern (i. E. , patterns from different pattern languages). An instance of such a generic solver exists that is capable of mining string patterns from string data sets. In our main application, promoter sequence analysis, there is a requirement to handle fault-tolerance, as the data intrinsically contains errors, and the phenomenon we are trying to capture is fundamentally degenerate. Our research contribution to fault-tolerant pattern extraction in string data sets is the use of a generic solver, based on a non-trivial formalisation of fault-tolerant pattern extraction as a constraint-based mining task. We identified the stages in the process of the extraction of such patterns where state-of-art strategies can be applied to prune the search space. We then developed a fault-tolerant pattern match function InsDels that generic constraint solving strategies can soundly tackle. We also focused on making local patterns actionable. The bottleneck of most local pattern extraction methods is the burden of spurious patterns. As the analysis of patterns by the application domain experts is time consuming, we cannot afford to present patterns without any objective clue about their relevancy. Therefore we have developed two methods of computing the expected number of patterns extracted in random data sets. If the number of extracted patterns is strongly different from the expected number from random data sets, one can then state that the results exhibits local associations that are a priori relevant because they are unexpected. Among others applications, we have applied our approach to support the discovery of new motifs in gene promoter sequences with promising results
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Sacan, Ahmet. "Similarity Search And Analysis Of Protein Sequences And Structures: A Residue Contacts Based Approach". Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609754/index.pdf.
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The advent of high-throughput sequencing and structure determination techniques has had a tremendous impact on our quest in cracking the language of life. The genomic and protein data is now being accumulated at a phenomenal rate, with the motivation of deriving insights into the function, mechanism, and evolution of the biomolecules, through analysis of their similarities, differences, and interactions. The rapid increase in the size of the biomolecular databases, however, calls for development of new computational methods for sensitive and efficient management and analysis of this information.
In this thesis, we propose and implement several approaches for accurate and highly efficient comparison and retrieval of protein sequences and structures. The observation that corresponding residues in related proteins share similar inter-residue contacts is exploited in derivation of a new set of biologically sensitive metric amino acid substitution matrices, yielding accurate alignment and comparison of proteins. The metricity of these matrices has allowed efficient indexing and retrieval of both protein sequences and structures. A landmark-guided embedding of protein sequences is developed to represent subsequences in a vector space for approximate, but extremely fast spatial indexing and similarity search.
Whereas protein structure comparison and search tasks were hitherto handled separately, we propose an integrated approach that serves both of these tasks and performs comparable to or better than other available methods. Our approach hinges on identification of similar residue contacts using distance-based indexing and provides the best of the both worlds: the accuracy of detailed structure alignment algorithms, at a speed comparable to that of the structure retrieval algorithms. We expect that the methods and tools developed in this study will find use in a wide range of application areas including annotation of new proteins, discovery of functional motifs, discerning evolutionary relationships among genes and species, and drug design and targeting.
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Wessel, Jennifer. "Human genetic-epidemiologic association analysis via allelic composition and DNA sequence similarity methods applications to blood-based gene expression biomarkers of disease /". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3237548.
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Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2006.Title from first page of PDF file (viewed December 12, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Wang, Danling. "Multifractal characterisation and analysis of complex networks". Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/48176/1/Danling_Wang_Thesis.pdf.
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Complex networks have been studied extensively due to their relevance to many real-world systems such as the world-wide web, the internet, biological and social systems. During the past two decades, studies of such networks in different fields have produced many significant results concerning their structures, topological properties, and dynamics. Three well-known properties of complex networks are scale-free degree distribution, small-world effect and self-similarity. The search for additional meaningful properties and the relationships among these properties is an active area of current research. This thesis investigates a newer aspect of complex networks, namely their multifractality, which is an extension of the concept of selfsimilarity. The first part of the thesis aims to confirm that the study of properties of complex networks can be expanded to a wider field including more complex weighted networks. Those real networks that have been shown to possess the self-similarity property in the existing literature are all unweighted networks. We use the proteinprotein interaction (PPI) networks as a key example to show that their weighted networks inherit the self-similarity from the original unweighted networks. Firstly, we confirm that the random sequential box-covering algorithm is an effective tool to compute the fractal dimension of complex networks. This is demonstrated on the Homo sapiens and E. coli PPI networks as well as their skeletons. Our results verify that the fractal dimension of the skeleton is smaller than that of the original network due to the shortest distance between nodes is larger in the skeleton, hence for a fixed box-size more boxes will be needed to cover the skeleton. Then we adopt the iterative scoring method to generate weighted PPI networks of five species, namely Homo sapiens, E. coli, yeast, C. elegans and Arabidopsis Thaliana. By using the random sequential box-covering algorithm, we calculate the fractal dimensions for both the original unweighted PPI networks and the generated weighted networks. The results show that self-similarity is still present in generated weighted PPI networks. This implication will be useful for our treatment of the networks in the third part of the thesis. The second part of the thesis aims to explore the multifractal behavior of different complex networks. Fractals such as the Cantor set, the Koch curve and the Sierspinski gasket are homogeneous since these fractals consist of a geometrical figure which repeats on an ever-reduced scale. Fractal analysis is a useful method for their study. However, real-world fractals are not homogeneous; there is rarely an identical motif repeated on all scales. Their singularity may vary on different subsets; implying that these objects are multifractal. Multifractal analysis is a useful way to systematically characterize the spatial heterogeneity of both theoretical and experimental fractal patterns. However, the tools for multifractal analysis of objects in Euclidean space are not suitable for complex networks. In this thesis, we propose a new box covering algorithm for multifractal analysis of complex networks. This algorithm is demonstrated in the computation of the generalized fractal dimensions of some theoretical networks, namely scale-free networks, small-world networks, random networks, and a kind of real networks, namely PPI networks of different species. Our main finding is the existence of multifractality in scale-free networks and PPI networks, while the multifractal behaviour is not confirmed for small-world networks and random networks. As another application, we generate gene interactions networks for patients and healthy people using the correlation coefficients between microarrays of different genes. Our results confirm the existence of multifractality in gene interactions networks. This multifractal analysis then provides a potentially useful tool for gene clustering and identification. The third part of the thesis aims to investigate the topological properties of networks constructed from time series. Characterizing complicated dynamics from time series is a fundamental problem of continuing interest in a wide variety of fields. Recent works indicate that complex network theory can be a powerful tool to analyse time series. Many existing methods for transforming time series into complex networks share a common feature: they define the connectivity of a complex network by the mutual proximity of different parts (e.g., individual states, state vectors, or cycles) of a single trajectory. In this thesis, we propose a new method to construct networks of time series: we define nodes by vectors of a certain length in the time series, and weight of edges between any two nodes by the Euclidean distance between the corresponding two vectors. We apply this method to build networks for fractional Brownian motions, whose long-range dependence is characterised by their Hurst exponent. We verify the validity of this method by showing that time series with stronger correlation, hence larger Hurst exponent, tend to have smaller fractal dimension, hence smoother sample paths. We then construct networks via the technique of horizontal visibility graph (HVG), which has been widely used recently. We confirm a known linear relationship between the Hurst exponent of fractional Brownian motion and the fractal dimension of the corresponding HVG network. In the first application, we apply our newly developed box-covering algorithm to calculate the generalized fractal dimensions of the HVG networks of fractional Brownian motions as well as those for binomial cascades and five bacterial genomes. The results confirm the monoscaling of fractional Brownian motion and the multifractality of the rest. As an additional application, we discuss the resilience of networks constructed from time series via two different approaches: visibility graph and horizontal visibility graph. Our finding is that the degree distribution of VG networks of fractional Brownian motions is scale-free (i.e., having a power law) meaning that one needs to destroy a large percentage of nodes before the network collapses into isolated parts; while for HVG networks of fractional Brownian motions, the degree distribution has exponential tails, implying that HVG networks would not survive the same kind of attack.
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Yan, Yiqing. "Scalable and accurate algorithms for computational genomics and dna-based digital storage". Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS078.
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La réduction des coûts et l'amélioration du débit de la technologie de séquençage ont entraîné de nouvelles avancées dans des applications telles que la médecine de précision et le stockage basé sur l'ADN. Cependant, le résultat séquencé contient des erreurs. Pour mesurer la similitude entre le résultat séquencé et la référence, la distance d'édition est préférée en pratique à la distance de Hamming en raison des indels. Le calcul de la distance d'édition est complexe quadratique. Par conséquent, l'analyse de similarité de séquence nécessite beaucoup de calculs. Dans cette thèse, nous introduisons deux algorithmes d'analyse de similarité de séquence précis et évolutifs, i) Accel-Align, un mappeur et un aligneur de séquence rapide basé sur la méthodologie seed–embed–extend, et ii) Motif-Search, une structure-efficace algorithme conscient pour récupérer les informations codées par les motifs composites à partir de l'archive ADN. Ensuite, nous utilisons Accel-Align comme un outil efficace pour étudier la conception d'accès aléatoire dans le stockage basé sur l'ADNCost reduction and throughput improvement in sequencing technology have resulted in new advances in applications such as precision medicine and DNA-based storage. However, the sequenced result contains errors. To measure the similarity between the sequenced result and reference, edit distance is preferred in practice over Hamming distance due to the indels. The primitive edit distance calculation is quadratic complex. Therefore, sequence similarity analysis is computationally intensive. In this thesis, we introduce two accurate and scalable sequence similarity analysis algorithms, i) Accel-Align, a fast sequence mapper and aligner based on the seed–embed–extend methodology, and ii) Motif-Search, an efficient structure-aware algorithm to recover the information encoded by the composite motifs from the DNA archive. Then, we use Accel-Align as an efficient tool to study the random access design in DNA-based storage
Libros sobre el tema "Sequence similarity analysis"
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Bilański, Piotr. Trypodendron laeve Eggers w Polsce na tle wybranych aspektów morfologicznych i genetycznych drwalników (Trypodendron spp., Coleoptera, Curculionidae, Scolytinae). Publishing House of the University of Agriculture in Krakow, 2019. http://dx.doi.org/10.15576/978-83-66602-38-0.
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In Poland, there are 4 species of the liypodendron genus: T lineaium Oliv., T domestkum L., T signature Fakir. and 7: laeve Egg. Trypodendron laeve is the leastknown of this group. Many factors had influence on the state of research on this species, including taxonomic aspects. Taking into account the unsatisfactory state of knowledge regarding the prevalence of T iaeve in Poland, as well as scarce information on the morphology of this species, research was undertaken to I) document the presence, including new sites, of T laeve in Poland and define, if possible, the habitat and trophic conditions that may affect its occurrence, as well as II) determinate suitability of biometric and genetic methods for correct identification of t laeve against the background of other ambrosia beetle species. Research on the occurrence of T laeve in Poland, was carried out on 143 areas located throughout the country, representing various environmental conditions, primarily such as species composition of tree stands, terrain, altitude (from 16 to 929 meters above sea level) and their location in relation to zoogeographic regions. The research material was obtained mainly using various types of traps for catching ambrosia beetles baited with pheromone. Only in a few cases when attacking the wood of trees, the imagines of ambrosia beetles were obtained without luring agents. The research was conducted in 2007-2016. From the insect individuals identified on the grounds of morphological traits as T lineatum, T laeve, T domesticum and T signatum, originating from selected locations in Poland, 3-11 specimens were collected, for which genetic analyses were performed based on the COI gene fragments obtained by PCR. The research included tests for following paramcter: s sequence similarity, phylogenetic, evolutionary divergence and genetic. structure. As a result of research on the occurrence of ambrosia beetles in Poland, a total of 44207 individuals belonging to four species were collected: T lineatutn, 7: laeve, T domesticum and T signatum, whose share was respectively: 49.2%, 31.4%; 19.1% and 0.3%. In Poland, 1: laeve's imagines were found in 124 out of 143 examined sites. The presence of L reeve has been documented for the first time in 14 zoogeographic regions. This species was commonly found on study areas located from 118 to 929 m above sea level. In Poland the tree species attacked by T Mate include Pinus sylvestris L. and Picea abies (L) H. Karst. In Poland, T laeve as a host plant prefers sylvestris and reaches the highest population densities in the stands of this species. The work presents the exact morphological characteristics of T laeve and indicates the most important features that distinguish it from the other Trypodendrun spp. occurring in Poland. It has also been shown that the best results in the determination of species of the liypodendron genus, regardless of their sex, can be obtained using phylogenetic analysis based on a fragment of the COI gene.
Capítulos de libros sobre el tema "Sequence similarity analysis"
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States, David J. y Mark S. Boguski. "Similarity and Homology". En Sequence Analysis Primer, 89–157. London: Palgrave Macmillan UK, 1991. http://dx.doi.org/10.1007/978-1-349-21355-9_3.
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Adjeroh, D. A., I. King y M. C. Lee. "Video sequence similarity matching". En Multimedia Information Analysis and Retrieval, 80–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/bfb0016490.
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Yap, Tieng K., Ophir Frieder y Robert L. Martino. "Multiprocessor Sequence Similarity Searching". En High Performance Computational Methods for Biological Sequence Analysis, 143–57. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4613-1391-5_6.
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Ryšavý, Petr y Filip Železný. "Estimating Sequence Similarity from Contig Sets". En Advances in Intelligent Data Analysis XVI, 272–83. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-68765-0_23.
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Subbotin, Sergei A. "Phylogenetic analysis of DNA sequence data." En Techniques for work with plant and soil nematodes, 265–82. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781786391759.0265.
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Abstract The goal of phylogenetics is to construct relationships that are true representations of the evolutionary history of a group of organisms or genes. The history inferred from phylogenetic analysis is usually depicted as branching in tree-like diagrams or networks. In nematology, phylogenetic studies have been applied to resolve a wide range of questions dealing with improving classifications and testing evolution processes, such as co-evolution, biogeography and many others. There are several main steps involved in a phylogenetic study: (i) selection of ingroup and outgroup taxa for a study; (ii) selection of one or several gene fragments for a study; (iii) sample collection, obtaining PCR products and sequencing of gene fragments; (iv) visualization, editing raw sequence data and sequence assembling; (v) search for sequence similarity in a public database; (vi) making and editing multiple alignment of sequences; (vii) selecting appropriate DNA model for a dataset; (viii) phylogenetic reconstruction using minimum evolution, maximum parsimony, maximum likelihood and Bayesian inference; (ix) visualization of tree files and preparation of tree for a publication; and (x) sequence submission to a public database. Molecular phylogenetic study requires particularly careful planning because it is usually relatively expensive in terms of the cost in reagents and time.
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Subbotin, Sergei A. "Phylogenetic analysis of DNA sequence data." En Techniques for work with plant and soil nematodes, 265–82. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781786391759.0015.
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Abstract The goal of phylogenetics is to construct relationships that are true representations of the evolutionary history of a group of organisms or genes. The history inferred from phylogenetic analysis is usually depicted as branching in tree-like diagrams or networks. In nematology, phylogenetic studies have been applied to resolve a wide range of questions dealing with improving classifications and testing evolution processes, such as co-evolution, biogeography and many others. There are several main steps involved in a phylogenetic study: (i) selection of ingroup and outgroup taxa for a study; (ii) selection of one or several gene fragments for a study; (iii) sample collection, obtaining PCR products and sequencing of gene fragments; (iv) visualization, editing raw sequence data and sequence assembling; (v) search for sequence similarity in a public database; (vi) making and editing multiple alignment of sequences; (vii) selecting appropriate DNA model for a dataset; (viii) phylogenetic reconstruction using minimum evolution, maximum parsimony, maximum likelihood and Bayesian inference; (ix) visualization of tree files and preparation of tree for a publication; and (x) sequence submission to a public database. Molecular phylogenetic study requires particularly careful planning because it is usually relatively expensive in terms of the cost in reagents and time.
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Ung, Huy Quang, Cuong Tuan Nguyen, Hung Tuan Nguyen y Masaki Nakagawa. "GSSF: A Generative Sequence Similarity Function Based on a Seq2Seq Model for Clustering Online Handwritten Mathematical Answers". En Document Analysis and Recognition – ICDAR 2021, 145–59. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-86331-9_10.
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Xie, Bo y Long Chen. "Automatic Scoring Model of Subjective Questions Based Text Similarity Fusion Model". En Proceeding of 2021 International Conference on Wireless Communications, Networking and Applications, 586–99. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2456-9_60.
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AbstractAI In this era, scene based translation and intelligent word segmentation are not new technologies. However, there is still no good solution for long and complex Chinese semantic analysis. The subjective question scoring still relies on the teacher's manual marking. However, there are a large number of examinations, and the manual marking work is huge. At present, the labor cost is getting higher and higher, the traditional manual marking method can't meet the demand The demand for automatic marking is increasingly strong in modern society. At present, the automatic marking technology of objective questions has been very mature and widely used. However, by reasons of the complexity and the difficulty of natural language processing technology in Chinese text, there are still many shortcomings in subjective questions marking, such as not considering the impact of semantics, word order and other issues on scoring accuracy. The automatic scoring technology of subjective questions is a complex technology, involving pattern recognition, machine learning, natural language processing and other technologies. Good results have been seen in the calculation method-based deep learning and machine learning. The rapid development of NLP technology has brought a new breakthrough for subjective question scoring. We integrate two deep learning models based on the Siamese Network through bagging to ensure the accuracy of the results, the text similarity matching model based on the birth networks and the score point recognition model based on the named entity recognition method respectively. Combining with the framework of deep learning, we use the simulated manual scoring method to extract and match the score point sequence of students’ answers with standard answers. The score recognition model effectively improves the efficiency of model calculation and long text keyword matching. The loss value of the final training score recognition model is about 0.9, and the accuracy is 80.54%. The accuracy of the training text similarity matching model is 86.99%, and the fusion model is single. The scoring time is less than 0.8s, and the accuracy is 83.43%.
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Bonnici, Vincenzo, Andrea Cracco y Giuditta Franco. "A k-mer Based Sequence Similarity for Pangenomic Analyses". En Machine Learning, Optimization, and Data Science, 31–44. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-95470-3_3.
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Yang, Wenlu, Xiongjun Pi y Liqing Zhang. "Similarity Analysis of DNA Sequences Based on the Relative Entropy". En Lecture Notes in Computer Science, 1035–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11539087_137.
Texto completoActas de conferencias sobre el tema "Sequence similarity analysis"
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Yusen Zhang y Xiangtian Yu. "Analysis of protein sequence similarity". En 2010 IEEE Fifth International Conference on Bio-Inspired Computing: Theories and Applications (BIC-TA). IEEE, 2010. http://dx.doi.org/10.1109/bicta.2010.5645085.
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Ketterlin, Alain y Pierre Ganarski. "Sequence Similarity and Multi-Date Image Segmentation". En 2007 International Workshop on the Analysis of Multi-temporal Remote Sensing Images. IEEE, 2007. http://dx.doi.org/10.1109/multitemp.2007.4293034.
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Lei, H. y Venu Govindaraju. "Similarity-driven sequence classification based on support vector machines". En Eighth International Conference on Document Analysis and Recognition (ICDAR'05). IEEE, 2005. http://dx.doi.org/10.1109/icdar.2005.217.
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Yang, Lina, Yuan Yan Tang, Yulong Wang, Huiwu Luo, Jianjia Pan, Haoliang Yuan, Xianwei Zheng, Chunli Li y Ting Shu. "Similarity analysis based on sparse representation for protein sequence comparison". En 2015 IEEE 2nd International Conference on Cybernetics (CYBCONF). IEEE, 2015. http://dx.doi.org/10.1109/cybconf.2015.7175964.
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Kong, Fen, Xu-ying Nan, Ping-an He, Qi Dai y Yu-hua Yao. "A sequence-segmented method applied to the similarity analysis of proteins". En 2012 IEEE 6th International Conference on Systems Biology (ISB). IEEE, 2012. http://dx.doi.org/10.1109/isb.2012.6314157.
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Hu, Jun, Hongxia Zhao, Xueyou Liang y Dan Chen. "The analysis of similarity for promoter sequence structures in yeast genes". En 2012 5th International Conference on Biomedical Engineering and Informatics (BMEI). IEEE, 2012. http://dx.doi.org/10.1109/bmei.2012.6513091.
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Dang, Xiaocui, Lina Yang, Yuan Yan Tang, Pu Wei y Hailong Su. "Nd5 Protein Sequence Similarity Analysis Based On Discrete Wavelet Transform And Fractal Dimension". En 2019 International Conference on Wavelet Analysis and Pattern Recognition (ICWAPR). IEEE, 2019. http://dx.doi.org/10.1109/icwapr48189.2019.8946464.
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Bai, Fenglan y Jun Xu. "Sequence Similarity Analysis of Buthus Martensii Neurotoxin Genes Based on Structure Matrix". En 2012 Fourth International Conference on Computational and Information Sciences (ICCIS). IEEE, 2012. http://dx.doi.org/10.1109/iccis.2012.277.
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Zhang, Hainan, Yanyan Lan, Jiafeng Guo, Jun Xu y Xueqi Cheng. "Reinforcing Coherence for Sequence to Sequence Model in Dialogue Generation". En Twenty-Seventh International Joint Conference on Artificial Intelligence {IJCAI-18}. California: International Joint Conferences on Artificial Intelligence Organization, 2018. http://dx.doi.org/10.24963/ijcai.2018/635.
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Sequence to sequence (Seq2Seq) approach has gained great attention in the field of single-turn dialogue generation. However, one serious problem is that most existing Seq2Seq based models tend to generate common responses lacking specific meanings. Our analysis show that the underlying reason is that Seq2Seq is equivalent to optimizing Kullback–Leibler (KL) divergence, thus does not penalize the case whose generated probability is high while the true probability is low. However, the true probability is unknown, which poses challenges for tackling this problem. Inspired by the fact that the coherence (i.e. similarity) between post and response is consistent with human evaluation, we hypothesize that the true probability of a response is proportional to the coherence degree. The coherence scores are then used as the reward function in a reinforcement learning framework to penalize the case whose generated probability is high while the true probability is low. Three different types of coherence models, including an unlearned similarity function, a pretrained semantic matching function, and an end-to-end dual learning architecture, are proposed in this paper. Experimental results on both Chinese Weibo dataset and English Subtitle dataset show that the proposed models produce more specific and meaningful responses, yielding better performances against Seq2Seq models in terms of both metric-based and human evaluations.
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Gupta, Manoj Kumar, Rajdeep Niyogi y Manoj Misra. "A framework for alignment-free methods to perform similarity analysis of biological sequence". En 2013 Sixth International Conference on Contemporary Computing (IC3). IEEE, 2013. http://dx.doi.org/10.1109/ic3.2013.6612216.
Texto completoInformes sobre el tema "Sequence similarity analysis"
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Gelb, Jr., Jack, Yoram Weisman, Brian Ladman y Rosie Meir. Identification of Avian Infectious Brochitis Virus Variant Serotypes and Subtypes by PCR Product Cycle Sequencing for the Rational Selection of Effective Vaccines. United States Department of Agriculture, diciembre de 2003. http://dx.doi.org/10.32747/2003.7586470.bard.
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Objectives 1. Determine the serotypic identities of 40 recent IBV isolates from commercial chickens raised in the USA and Israel. 2. Sequence all IBV field isolates using PCR product cycle sequencing and analyze their S 1 sequence to detennine their homology to other strains in the Genbank and EMBL databases. 3. Select vaccinal strains with the highest S 1 sequence homology to the field isolates and perform challenge of immunity studies in chickens in laboratory trials to detennine level of protection afforded by the vaccines. Background Infectious bronchitis (IB) is a common, economically important disease of the chicken. IB occurs as a respiratory form, associated with airsacculitis, condemnation, and mortality of meat-type broilers, a reproductive form responsible for egg production losses in layers and breeders, and a renal form causing high mortality in broilers and pullets. The causative agent is avian coronavirus infectious bronchitis virus (IBV). Replication of the virus' RNA genome is error-prone and mutations commonly result. A major target for mutation is the gene encoding the spike (S) envelope protein used by the virus to attach and infect the host cell. Mutations in the S gene result in antigenic changes that can lead to the emergence of variant serotypes. The S gene is able to tolerate numerous mutations without compromising the virus' ability to replicate and cause disease. An end result of the virus' "flexibility" is that many strains of IBV are capable of existing in nature. Once formed, new mutant strains, often referred to as variants, are soon subjected to immunological selection so that only the most antigenically novel variants survive in poultry populations. Many novel antigenic variant serotypes and genotypes have been isolated from commercial poultry flocks. Identification of the field isolates of IBV responsible for outbreaks is critical for selecting the appropriate strain(s) for vaccination. Reverse transcriptase polymerase chain reaction (RT-PCR) of the Sl subunit of the envelope spike glycoprotein gene has been a common method used to identify field strains, replacing other time-consuming or less precise tests. Two PCR approaches have been used for identification, restriction fragment length polymorphism (RFLP) and direct automated cycle sequence analysis of a diagnostically relevant hypervariab1e region were compared in our BARD research. Vaccination for IB, although practiced routinely in commercial flocks, is often not protective. Field isolates responsible for outbreaks may be unrelated to the strain(s) used in the vaccination program. However, vaccines may provide varying degrees of cross- protection vs. unrelated field strains so vaccination studies should be performed. Conclusions RFLP and S1 sequence analysis methods were successfully performed using the field isolates from the USA and Israel. Importantly, the S1 sequence analysis method enabled a direct comparison of the genotypes of the field strains by aligning them to sequences in public databases e.g. GenBank. Novel S1 gene sequences were identified in both USA and Israel IBVs but greater diversity was observed in the field isolates from the USA. One novel genotype, characterized in this project, Israel/720/99, is currently being considered for development as an inactivated vaccine. Vaccination with IBV strains in the US (Massachusetts, Arkansas, Delaware 072) or in Israel (Massachusetts, Holland strain) provided higher degrees of cross-protection vs. homologous than heterologous strain challenge. In many cases however, vaccination with two strains (only studies with US strains) produced reasonable cross-protection against heterologous field isolate challenge. Implications S1 sequence analysis provides numerical similarity values and phylogenetic information that can be useful, although by no means conclusive, in developing vaccine control strategies. Identification of many novel S1 genotypes of IBV in the USA is evidence that commercial flocks will be challenged today and in the future with strains unrelated to vaccines. In Israel, monitoring flocks for novel IBV field isolates should continue given the identification of Israel/720/99, and perhaps others in the future. Strains selected for vaccination of commercial flocks should induce cross- protection against unrelated genotypes. Using diverse genotypes for vaccination may result in immunity against unrelated field strains.
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Dickman, Martin B. y Oded Yarden. Role of Phosphorylation in Fungal Spore Germination. United States Department of Agriculture, agosto de 1993. http://dx.doi.org/10.32747/1993.7568761.bard.
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Spore germination is a common and fundamental event in fungal development and in many instances an essential phase of fungal infection and dissemination. Spore germination is also critical for hyperparasites to function as biocontrol agents as well as in fermentation proceses. Our common objective is to understand the mechanisms which regulated spore germination and identify factors involved in pathogenicity related prepenetration development. Our approach is to exploit the overall similarity among filamentous fungi using both a plant pathogen (Colletotricum trifolii) and a model system that is genetically sophisticated (Neurospora crassa). The simulataneous use of two organisms has the advantage of the available tools in Neurospora to rapidly advance the functional analysis of genes involved in spore germination and development of an economically important fungal phytopathogen. Towards this we have isolated a protein kinase gene from C. trifolii (TB3) that is maximally expressed during the first hour of conidial germination and prior to any visible gene tube formation. Based on sequence similarities with other organisms, this gene is likely to be involved in the proliferative response in the fungus. In addition, TB3 was able to functionally complement a N. crassa mutant (COT-1). Pharmacological studies indicated the importance of calmodulin in both germination and appressorium differentiation. Using an antisense vector from N. crassa, direct inhibition of calmodulin results in prevention of differentiation as well as pathogenicity. Both cAMP dependent protein kinase (PKA) and protein kinase C (PKC) like genes have been cloned from C. trifolii. Biochemical inhibition of PKA prevents germination; biochemical inhibitors of PKC prevents appressorium differentiation. In order to analyze reversible phosphorylation as a regulatory mechanism, some ser.thr dephosphorylative events have also been analyzed. Type 2A and Type 2B (calcineurin) phosphatases have been identified and structurally and functionally analyzed in N. crassa during this project. Both phosphatases are essential for hyphal growth and maintenance of proper hyphal architecture. In addition, a first novel-type (PPT/PP5-like) ser/thr phosphatase has been identified in a filamentous fungus. The highly collaborative project has improved our understanding of a fundamental process in fungi, and has identified targets which can be used to develop new approaches for control of fungal plant pathogens as well as improve the performance of beneficial fungi in the field and in industry. In addition, the feasibility of molecular technology transfer in comparative mycology has been demonstrated.
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Cohen, Yuval, Christopher A. Cullis y Uri Lavi. Molecular Analyses of Soma-clonal Variation in Date Palm and Banana for Early Identification and Control of Off-types Generation. United States Department of Agriculture, octubre de 2010. http://dx.doi.org/10.32747/2010.7592124.bard.
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Date palm (Phoenix dactylifera L.) is the major fruit tree grown in arid areas in the Middle East and North Africa. In the last century, dates were introduced to new regions including the USA. Date palms are traditionally propagated through offshoots. Expansion of modern date palm groves led to the development of Tissue Culture propagation methods that generate a large number of homogenous plants, have no seasonal effect on plant source and provide tools to fight the expansion of date pests and diseases. The disadvantage of this procedure is the occurrence of off-type trees which differ from the original cultivar. In the present project we focused on two of the most common date palm off-types: (1) trees with reduced fruit setting, in which most of the flowers turn into three-carpel parthenocarpic fruits. In a severe form, multi-carpel flowers and fruitlets (with up to six or eight carpels instead of the normal three-carpel flowers) are also formed. (2) dwarf trees, having fewer and shorter leaves, very short trunk and are not bearing fruits at their expected age, compared to the normal trees. Similar off-types occur in other crop species propagated by tissue culture, like banana (mainly dwarf plants) or oil palm (with a common 'Mantled' phenotype with reduced fruit setting and occurrence of supernumerary carpels). Some off-types can only be detected several years after planting in the fields. Therefore, efficient methods for prevention of the generation of off-types, as well as methods for their detection and early removal, are required for date palms, as well as for other tissue culture propagated crops. This research is aimed at the understanding of the mechanisms by which off-types are generated, and developing markers for their early identification. Several molecular and genomic approaches were applied. Using Methylation Sensitive AFLP and bisulfite sequencing, we detected changes in DNA methylation patterns occurring in off-types. We isolated and compared the sequence and expression of candidate genes, genes related to vegetative growth and dwarfism and genes related to flower development. While no sequence variation were detected, changes in gene expression, associated with the severity of the "fruit set" phenotype were detected in two genes - PdDEF (Ortholog of rice SPW1, and AP3 B type MADS box gene), and PdDIF (a defensin gene, highly homologous to the oil palm gene EGAD). We applied transcriptomic analyses, using high throughput sequencing, to identify genes differentially expressed in the "palm heart" (the apical meristem and the region of embryonic leaves) of dwarf vs. normal trees. Among the differentially expressed genes we identified genes related to hormonal biosynthesis, perception and regulation, genes related to cell expansion, and genes related to DNA methylation. Using Representation Difference Analyses, we detected changes in the genomes of off-type trees, mainly chloroplast-derived sequences that were incorporated in the nuclear genome and sequences of transposable elements. Sequences previously identified as differing between normal and off-type trees of oil palms or banana, successfully identified variation among date palm off-types, suggesting that these represent highly labile regions of monocot genomes. The data indicate that the date palm genome, similarly to genomes of other monocot crops as oil palm and banana, is quite unstable when cells pass through a cycle of tissue culture and regeneration. Changes in DNA sequences, translocation of DNA fragments and alteration of methylation patterns occur. Consequently, patterns of gene expression are changed, resulting in abnormal phenotypes. The data can be useful for future development of tools for early identification of off-type as well as for better understanding the phenomenon of somaclonal variation during propagation in vitro.
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Fridman, Eyal y Eran Pichersky. Tomato Natural Insecticides: Elucidation of the Complex Pathway of Methylketone Biosynthesis. United States Department of Agriculture, diciembre de 2009. http://dx.doi.org/10.32747/2009.7696543.bard.
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Plant species synthesize a multitude of specialized compounds 10 help ward off pests. and these in turn may well serve as an alternative to synthetic pesticides to reduce environmental damage and health risks to humans. The general goal of this research was to perform a genetic and biochemical dissection of the natural-insecticides methylketone pathway that is specific to the glandular trichomes of the wild species of tomato, Solanumhabrochaites f. glabratum (accession PI126449). Previous study conducted by us have demonstrated that these compounds are synthesized de novo as a derivate pathway of the fatty acid biosynthesis, and that a key enzyme. designated MethylketoneSynthase 1 (MKS 1). catalyzes conversion of the intermediate B-ketoacyl- ACPs to the corresponding Cn-1 methylketones. The approach taken in this proposed project was to use an interspecific F2 population. derived from the cross between the cultivated lV182 and the wild species PIl26449. for three objectives: (i) Analyze the association between allelic status of candidate genes from the fatty acid biosynthesis pathway with the methylketone content in the leaves (ii) Perform bulk segregant analysis of genetic markers along the tomato genome for identifying genomic regions that harbor QTLs for 2TD content (iii) Apply differential gene expression analysis using the isolated glands of bulk segregant for identifying new genes that are involved in the pathway. The genetic mapping in the interspecific F2 population included app. 60 genetic markers, including the candidate genes from the FAS pathway and SSR markers spread evenly across the genome. This initial; screening identified 5 loci associated with MK content including the candidate genes MKS1, ACC and MaCoA:ACP trans. Interesting observation in this genetic analysis was the connection between shape and content of the glands, i.e. the globularity of the four cells, typical to the wild species. was associated with increased MK in the segregating population. In the next step of the research transcriptomic analysis of trichomes from high- and 10w-MK plants was conducted. This analysis identified a new gene, Methy1ketone synthase 2 (MKS2), whose protein product share sequence similarity to the thioesterase super family of hot-dog enzymes. Genetic analysis in the segregating population confirmed its association with MK content, as well as its overexpression in E. coli that led to formation of MK in the media. There are several conclusions drawn from this research project: (i) the genetic control of MK accumulation in the trichomes is composed of biochemical components in the FAS pathway and its vicinity (MKS 1 and MKS2). as well as genetic factors that mediate the morphology of these specialized cells. (ii) the biochemical pathway is now realized different from what was hypothesized before with MKS2 working upstream to I\1KS 1 and serves as the interface between primary (fatty acids) and secondary (MK) metabolism. We are currently testing the possible physical interactions between these two proteins in vitro after the genetic analysis showed clear epistatic interactions. (iii) the regulation of the pathway that lead to specialized metabolism in the wild species is largely mediated by transcription and one of the achievements of this project is that we were able to isolate and verify the specificity of the MKS1 promoter to the trichomes which allows manipulation of the pathways in these cells (currently in progress). The scientific implications of this research project is the advancement in our knowledge of hitherto unknown biochemical pathway in plants and new leads for studying a new family in plants (hot dog thioesterase). The agricultural and biotechnological implication are : (i) generation of new genetic markers that could assist in importing this pathway to cultivated tomato hence enhancing its natural resistance to insecticides, (ii) the discovery of MKS2 adds a new gene for genetic engineering of plants for making new fatty acid derived compounds. This could be assisted with the use of the isolated and verified MKS1 promoter. The results of this research were summarized to a manuscript that was published in Plant Physiology (cover paper). to a chapter in a proceeding book. and one patent was submitted in the US.
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Michelmore, Richard, Eviatar Nevo, Abraham Korol y Tzion Fahima. Genetic Diversity at Resistance Gene Clusters in Wild Populations of Lactuca. United States Department of Agriculture, febrero de 2000. http://dx.doi.org/10.32747/2000.7573075.bard.
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Genetic resistance is often the least expensive, most effective, and ecologically-sound method of disease control. It is becoming apparent that plant genomes contain large numbers of disease resistance genes. However, the numbers of different resistance specificities within a genepool and the genetic mechanisms generating diversity are poorly understood. Our objectives were to characterize diversity in clusters of resistance genes in wild progenitors of cultivated lettuce in Israel and California in comparison to diversity within cultivated lettuce, and to determine the extent of gene flow, recombination, and genetic instability in generating variation within clusters of resistance genes. Genetic diversity of resistance genes was analyzed in wild and cultivated germplasm using molecular markers derived from lettuce resistance gene sequences of the NBS-LRR type that mapped to the major cluster if resistance genes in lettuce (Sicard et al. 1999). Three molecular markers, one microsatellite marker and two SCAR markers that amplified LRR- encoding regions, were developed from sequences of resistance gene homologs at the Dm3 cluster (RGC2s) in lettuce. Variation for these markers was assessed in germplasm including 74 genotypes of cultivated lettuce, L. saliva and 71 accessions of the three wild Lactuca spp., L. serriola, L. saligna and L. virosa that represent the major species in the sexually accessible genepool for lettuce. Diversity was also studied within and between natural populations of L. serriola from Israel and California. Large numbers of haplotypes were detected indicating the presence of numerous resistance genes in wild species. We documented a variety of genetic events occurring at clusters of resistance genes for the second objective (Sicard et al., 1999; Woo el al., in prep; Kuang et al., in prepb). The diversity of resistance genes in haplotypes provided evidence for gene duplication and unequal crossing over during the evolution of this cluster of resistance genes. Comparison of nine resistance genes in cv. Diana identified 22 gene conversion and five intergenic recombinations. We cloned and sequenced a 700 bp region from the middle of RGC2 genes from six genotypes, two each from L. saliva, L. serriola, and L. saligna . We have identified over 60 unique RGC2 sequences. Phylogenetic analysis surprisingly demonstrated much greater similarity between than within genotypes. This led to the realization that resistance genes are evolving much slower than had previously been assumed and to a new model as to how resistance genes are evolving (Michelmore and Meyers, 1998). The genetic structure of L. serriola was studied using 319 AFLP markers (Kuang et al., in prepa). Forty-one populations from Turkey, Armenia, Israel, and California as well as seven European countries were examined. AFLP marker data showed that the Turkish and Armenian populations were the most polymorphic populations and the European populations were the least. The Davis, CA population, a recent post-Columbian colonization, showed medium genetic diversity and was genetically close to the Turkish populations. Our results suggest that Turkey - Armenia may be the center of origin and diversity of L. serriola and may therefore have the greatest diversity of resistance genes. Our characterization of the diversity of resistance genes and the genetic mechanisms generating it will allow informed exploration, in situ and ex situ conservation, and utilization of germplasm resources for disease control. The results of this project provide the basis for our future research work, which will lead to a detailed understanding of the evolution of resistance genes in plants.
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Ueti, Massaro Wilson y Monica Leszkowicz Mazuz. Identification, characterization and testing of geographically conserved Babesia bovis vaccine antigen candidates. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2022. http://dx.doi.org/10.32747/2022.8134143.bard.
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During the development of this project, we selected four potential B. bovis antigens for a subunit vaccine to prevent the clinical signs of acute bovine babesiosis. Selection of the target antigens was based on: (1) profile of expression in parasite blood stages; (2) prediction for protein location on the parasite surface and/or on the surface of infected red blood cells; and (3) target conservation between US and Israeli strains of B. bovis. Following these criteria, the B. bovis targets BBOV_IV009170, BBOV_III007410, BBOV_II001790, and BBOV_III008720 were selected. Full-length genomic sequences of these four targets were compared between Israeli and US strains of B. bovis. Four Israeli parasite strains/isolates were selected for gene conservation analysis: sample ID # 3330 (from Refet Netofa); sample ID # 2673 (Refet Netofa); Sample ID Newe Yaar - Shahar; and the Israeli B. bovis cultured live vaccine 2S61411. The reference B. bovis Texas stain was also used in the analysis. Sequencing analysis showed considerable levels of conservation ranging from 72.2-91.1% and 84.6-94.1% of amino acid identity and similarity, respectively, by comparing Israeli and US B. bovis strains. Recombinant version of the four target antigens were produced in E. coli, purified by nickel columns, and used for antigenic and immunogenic analyses. Antigenic analysis revealed that B. bovis-infected cattle develop high antibody titers to BBOV_III008720. In contrast, no antibodies against BBOV_IV009170, BBOV_III007410, and BBOV_II001790 were detected in sera from infected cattle. Vaccine trial of the four antigens in cattle is currently being carried out. However, preliminary data show that after three inoculations all vaccinated animals (n=5) seroconverted to all four B. bovis antigens. At the time of the preparation of this report, vaccinated and control animals are being challenged with a virulent B. bovis strain from Israel to evaluate protection. Results from the vaccination/trial experiment will set the future directions of this work. Considering the overall results from this project, two manuscripts are currently in preparation. A manuscript currently in preparation will describe the bioinformatics analysis and antigenic evaluation of the four transmembrane B. bovis proteins as potential targets for a subunit vaccine. A second manuscript will report the results from the vaccination/challenge trial. We believe that we have successfully accomplished our objective in this project. By developing this work, we have identified, expressed, and tested conserved antigens for a potential subunit vaccine against B. bovis, and have advanced the state-of-the-art concerning the development of an efficient and sustainable control strategy to bovine babesiosis.
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Levisohn, Sharon, Maricarmen Garcia, David Yogev y Stanley Kleven. Targeted Molecular Typing of Pathogenic Avian Mycoplasmas. United States Department of Agriculture, enero de 2006. http://dx.doi.org/10.32747/2006.7695853.bard.
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Intraspecies identification (DNA "fingerprinting") of pathogenic avian mycoplasmas is a powerful tool for epidemiological studies and monitoring strain identity. However the only widely method available for Mycoplasma gallisepticum (MG) and M. synoviae (MS)wasrandom amplified polymorphic DNA (RAPD). This project aimed to develop alternative and supplementary typing methods that will overcome the major constraints of RAPD, such as the need for isolation of the organism in pure culture and the lack of reproducibility intrinsic in the method. Our strategy focussed on recognition of molecular markers enabling identification of MG and MS vaccine strains and, by extension, pathogenic potential of field isolates. Our first aim was to develop PCR-based systems which will allow amplification of specific targeted genes directly from clinical material. For this purpose we evaluated the degree of intraspecies heterogeneity in genes encoding variable surface antigens uniquely found in MG all of which are putative pathogenicity factors. Phylogenic analysis of targeted sequences of selected genes (pvpA, gapA, mgc2, and lp) was employed to determine the relationship among MG strains.. This method, designated gene targeted sequencing (GTS), was successfully employed to identify strains and to establish epidemiologically-linked strain clusters. Diagnostic PCR tests were designed and validated for each of the target genes, allowing amplification of specific nucleotide sequences from clinical samples. An mgc2-PCR-RFLP test was designed for rapid differential diagnosis of MG vaccine strains in Israel. Addressing other project goals, we used transposon mutagenesis and in vivo and in vitro models for pathogenicity to correlated specific changes in target genes with biological properties that may impact the course of infection. An innovative method for specific detection and typing of MS strains was based on the hemagglutinin-encoding gene vlhA, uniquely found in this species. In parallel, we evaluated the application of amplified fragment length polymorphism (AFLP) in avian mycoplasmas. AFLP is a highly discriminatory method that scans the entire genome using infrequent restriction site PCR. As a first step the method was found to be highly correlated with other DNA typing methods for MG species and strain differentiation. The method is highly reproducible and relatively rapid, although it is necessary to isolate the strain to be tested. Both AFLP and GTS are readily to amenable to computer-assisted analysis of similarity and construction of a data-base resource. The availability of improved and diverse tools will help realize the full potential of molecular typing of avian mycoplasmas as an integral and essential part of mycoplasma control programs.
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Paran, Ilan y Allen Van Deynze. Regulation of pepper fruit color, chloroplasts development and their importance in fruit quality. United States Department of Agriculture, enero de 2014. http://dx.doi.org/10.32747/2014.7598173.bard.
Texto completoResumen
Pepper exhibits large natural variation in chlorophyll content in the immature fruit. To dissect the genetic and molecular basis of this variation, we conducted QTL mapping for chlorophyll content in a cross between light and dark green-fruited parents, PI 152225 and 1154. Two major QTLs, pc1 and pc10, that control chlorophyll content by modulation of chloroplast compartment size in a fruit-specific manner were detected in chromosomes 1 and 10, respectively. The pepper homolog of GOLDEN2- LIKE transcription factor (CaGLK2) was found as underlying pc10, similar to its effect on tomato fruit chloroplast development. A candidate gene for pc1was found as controlling chlorophyll content in pepper by the modulation of chloroplast size and number. Fine mapping of pc1 aided by bulked DNA and RNA-seq analyses enabled the identification of a zinc finger transcription factor LOL1 (LSD-One-Like 1) as a candidate gene underlying pc1. LOL1 is a positive regulator of oxidative stress- induced cell death in Arabidopsis. However, over expression of the rice ortholog resulted in an increase of chlorophyll content. Interestingly, CaAPRR2 that is linked to the QTL and was found to affect immature pepper fruit color in a previous study, did not have a significant effect on chlorophyll content in the present study. Verification of the candidate's function was done by generating CRISPR/Cas9 knockout mutants of the orthologues tomato gene, while its knockout experiment in pepper by genome editing is under progress. Phenotypic similarity as a consequence of disrupting the transcription factor in both pepper and tomato indicated its functional conservation in controlling chlorophyll content in the Solanaceae. A limited sequence diversity study indicated that null mutations in CaLOL1 and its putative interactorCaMIP1 are present in C. chinensebut not in C. annuum. Combinations of mutations in CaLOL1, CaMIP1, CaGLK2 and CaAPRR2 are required for the creation of the extreme variation in chlorophyll content in Capsicum.
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Or, Etti, David Galbraith y Anne Fennell. Exploring mechanisms involved in grape bud dormancy: Large-scale analysis of expression reprogramming following controlled dormancy induction and dormancy release. United States Department of Agriculture, diciembre de 2002. http://dx.doi.org/10.32747/2002.7587232.bard.
Texto completoResumen
The timing of dormancy induction and release is very important to the economic production of table grape. Advances in manipulation of dormancy induction and dormancy release are dependent on the establishment of a comprehensive understanding of biological mechanisms involved in bud dormancy. To gain insight into these mechanisms we initiated the research that had two main objectives: A. Analyzing the expression profiles of large subsets of genes, following controlled dormancy induction and dormancy release, and assessing the role of known metabolic pathways, known regulatory genes and novel sequences involved in these processes B. Comparing expression profiles following the perception of various artificial as well as natural signals known to induce dormancy release, and searching for gene showing similar expression patterns, as candidates for further study of pathways having potential to play a central role in dormancy release. We first created targeted EST collections from V. vinifera and V. riparia mature buds. Clones were randomly selected from cDNA libraries prepared following controlled dormancy release and controlled dormancy induction and from respective controls. The entire collection (7920 vinifera and 1194 riparia clones) was sequenced and subjected to bioinformatics analysis, including clustering, annotations and GO classifications. PCR products from the entire collection were used for printing of cDNA microarrays. Bud tissue in general, and the dormant bud in particular, are under-represented within the grape EST database. Accordingly, 59% of the our vinifera EST collection, composed of 5516 unigenes, are not included within the current Vitis TIGR collection and about 22% of these transcripts bear no resemblance to any known plant transcript, corroborating the current need for our targeted EST collection and the bud specific cDNA array. Analysis of the V. riparia sequences yielded 814 unigenes, of which 140 are unique (keilin et al., manuscript, Appendix B). Results from computational expression profiling of the vinifera collection suggest that oxidative stress, calcium signaling, intracellular vesicle trafficking and anaerobic mode of carbohydrate metabolism play a role in the regulation and execution of grape-bud dormancy release. A comprehensive analysis confirmed the induction of transcription from several calcium–signaling related genes following HC treatment, and detected an inhibiting effect of calcium channel blocker and calcium chelator on HC-induced and chilling-induced bud break. It also detected the existence of HC-induced and calcium dependent protein phosphorylation activity. These data suggest, for the first time, that calcium signaling is involved in the mechanism of dormancy release (Pang et al., in preparation). We compared the effects of heat shock (HS) to those detected in buds following HC application and found that HS lead to earlier and higher bud break. We also demonstrated similar temporary reduction in catalase expression and temporary induction of ascorbate peroxidase, glutathione reductase, thioredoxin and glutathione S transferase expression following both treatments. These findings further support the assumption that temporary oxidative stress is part of the mechanism leading to bud break. The temporary induction of sucrose syntase, pyruvate decarboxylase and alcohol dehydrogenase indicate that temporary respiratory stress is developed and suggest that mitochondrial function may be of central importance for that mechanism. These finding, suggesting triggering of identical mechanisms by HS and HC, justified the comparison of expression profiles of HC and HS treated buds, as a tool for the identification of pathways with a central role in dormancy release (Halaly et al., in preparation). RNA samples from buds treated with HS, HC and water were hybridized with the cDNA arrays in an interconnected loop design. Differentially expressed genes from the were selected using R-language package from Bioconductor project called LIMMA and clones showing a significant change following both HS and HC treatments, compared to control, were selected for further analysis. A total of 1541 clones show significant induction, of which 37% have no hit or unknown function and the rest represent 661 genes with identified function. Similarly, out of 1452 clones showing significant reduction, only 53% of the clones have identified function and they represent 573 genes. The 661 induced genes are involved in 445 different molecular functions. About 90% of those functions were classified to 20 categories based on careful survey of the literature. Among other things, it appears that carbohydrate metabolism and mitochondrial function may be of central importance in the mechanism of dormancy release and studies in this direction are ongoing. Analysis of the reduced function is ongoing (Appendix A). A second set of hybridizations was carried out with RNA samples from buds exposed to short photoperiod, leading to induction of bud dormancy, and long photoperiod treatment, as control. Analysis indicated that 42 genes were significant difference between LD and SD and 11 of these were unique.
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Rafaeli, Ada y Russell Jurenka. Molecular Characterization of PBAN G-protein Coupled Receptors in Moth Pest Species: Design of Antagonists. United States Department of Agriculture, diciembre de 2012. http://dx.doi.org/10.32747/2012.7593390.bard.
Texto completoResumen
The proposed research was directed at determining the activation/binding domains and gene regulation of the PBAN-R’s thereby providing information for the design and screening of potential PBAN-R-blockers and to indicate possible ways of preventing the process from proceeding to its completion. Our specific aims included: (1) The identification of the PBAN-R binding domain by a combination of: (a) in silico modeling studies for identifying specific amino-acid side chains that are likely to be involved in binding PBAN with the receptor and; (b) bioassays to verify the modeling studies using mutant receptors, cell lines and pheromone glands (at tissue and organism levels) against selected, designed compounds to confirm if compounds are agonists or antagonists. (2) The elucidation ofthemolecular regulationmechanisms of PBAN-R by:(a) age-dependence of gene expression; (b) the effect of hormones and; (c) PBAN-R characterization in male hair-pencil complexes. Background to the topic Insects have several closely related G protein-coupled receptors (GPCRs) belonging to the pyrokinin/PBAN family, one with the ligand pheromone biosynthesis activating neuropeptide or pyrokinin-2 and another with diapause hormone or pyrokinin-1 as a ligand. We were unable to identify the diapause hormone receptor from Helicoverpa zea despite considerable effort. A third, related receptor is activated by a product of the capa gene, periviscerokinins. The pyrokinin/PBAN family of GPCRs and their ligands has been identified in various insects, such as Drosophila, several moth species, mosquitoes, Triboliumcastaneum, Apis mellifera, Nasoniavitripennis, and Acyrthosiphon pisum. Physiological functions of pyrokinin peptides include muscle contraction, whereas PBAN regulates pheromone production in moths plus other functions indicating the pleiotropic nature of these ligands. Based on the alignment of annotated genomic sequences, the primary and secondary structures of the pyrokinin/PBAN family of receptors have similarity with the corresponding structures of the capa or periviscerokinin receptors of insects and the neuromedin U receptors found in vertebrates. Major conclusions, solutions, achievements Evolutionary trace analysisof receptor extracellular domains exhibited several class-specific amino acid residues, which could indicate putative domains for activation of these receptors by ligand recognition and binding. Through site-directed point mutations, the 3rd extracellular domain of PBAN-R was shown to be critical for ligand selection. We identified three receptors that belong to the PBAN family of GPCRs and a partial sequence for the periviscerokinin receptor from the European corn borer, Ostrinianubilalis. Functional expression studies confirmed that only the C-variant of the PBAN-R is active. We identified a non-peptide agonist that will activate the PBAN-receptor from H. zea. We determined that there is transcriptional control of the PBAN-R in two moth species during the development of the pupa to adult, and we demonstrated that this transcriptional regulation is independent of juvenile hormone biosynthesis. This transcriptional control also occurs in male hair-pencil gland complexes of both moth species indicating a regulatory role for PBAN in males. Ultimate confirmation for PBAN's function in the male tissue was revealed through knockdown of the PBAN-R using RNAi-mediated gene-silencing. Implications, both scientific and agricultural The identification of a non-peptide agonist can be exploited in the future for the design of additional compounds that will activate the receptor and to elucidate the binding properties of this receptor. The increase in expression levels of the PBAN-R transcript was delineated to occur at a critical period of 5 hours post-eclosion and its regulation can now be studied. The mysterious role of PBAN in the males was elucidated by using a combination of physiological, biochemical and molecular genetics techniques.