Self-similarity of higher-order moving averages

Science.gov (United States)

Arianos, Sergio; Carbone, Anna; Türk, Christian

2011-10-01

In this work, higher-order moving average polynomials are defined by straightforward generalization of the standard moving average. The self-similarity of the polynomials is analyzed for fractional Brownian series and quantified in terms of the Hurst exponent H by using the detrending moving average method. We prove that the exponent H of the fractional Brownian series and of the detrending moving average variance asymptotically agree for the first-order polynomial. Such asymptotic values are compared with the results obtained by the simulations. The higher-order polynomials correspond to trend estimates at shorter time scales as the degree of the polynomial increases. Importantly, the increase of polynomial degree does not require to change the moving average window. Thus trends at different time scales can be obtained on data sets with the same size. These polynomials could be interesting for those applications relying on trend estimates over different time horizons (financial markets) or on filtering at different frequencies (image analysis).

Similar representations of sequence knowledge in young and older adults: A study of effector independent transfer

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Jonathan Sebastiaan Barnhoorn

2016-08-01

Full Text Available Older adults show reduced motor performance and changes in motor skill development. To better understand these changes, we studied differences in sequence knowledge representations between young and older adults using a transfer task. Transfer, or the ability to apply motor skills flexibly, is highly relevant in day-to-day motor activity and facilitates generalization of learning to new contexts. By using movement types that are completely unrelated in terms of muscle activation and response location, we focused on transfer facilitated by the early, visuospatial system.We tested 32 right-handed older adults (65 – 74 and 32 young adults (18 – 30. During practice of a discrete sequence production task, participants learned two 6-element sequences using either unimanual key-presses (KPs or by moving a lever with lower arm flexion-extension (FE movements. Each sequence was performed 144 times. They then performed a test phase consisting of familiar and random sequences performed with the type of movements not used during practice. Both age groups displayed transfer from FE to KP movements as indicated by faster performance on the familiar sequences in the test phase. Only young adults transferred their sequence knowledge from KP to FE movements. In both directions, the young showed higher transfer than older adults. These results suggest that the older participants, like the young, represented their sequences in an abstract visuospatial manner. Transfer was asymmetric in both age groups: there was more transfer from FE to KP movements than vice versa. This similar asymmetry is a further indication that the types of representations that older adults develop are comparable to those that young adults develop. We furthermore found that older adults improved less during FE practice, gained less explicit knowledge, displayed a smaller visuospatial working memory capacity and had lower processing speed than young adults. Despite the many differences

Testing statistical significance scores of sequence comparison methods with structure similarity

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Leunissen Jack AM

2006-10-01

Full Text Available Abstract Background In the past years the Smith-Waterman sequence comparison algorithm has gained popularity due to improved implementations and rapidly increasing computing power. However, the quality and sensitivity of a database search is not only determined by the algorithm but also by the statistical significance testing for an alignment. The e-value is the most commonly used statistical validation method for sequence database searching. The CluSTr database and the Protein World database have been created using an alternative statistical significance test: a Z-score based on Monte-Carlo statistics. Several papers have described the superiority of the Z-score as compared to the e-value, using simulated data. We were interested if this could be validated when applied to existing, evolutionary related protein sequences. Results All experiments are performed on the ASTRAL SCOP database. The Smith-Waterman sequence comparison algorithm with both e-value and Z-score statistics is evaluated, using ROC, CVE and AP measures. The BLAST and FASTA algorithms are used as reference. We find that two out of three Smith-Waterman implementations with e-value are better at predicting structural similarities between proteins than the Smith-Waterman implementation with Z-score. SSEARCH especially has very high scores. Conclusion The compute intensive Z-score does not have a clear advantage over the e-value. The Smith-Waterman implementations give generally better results than their heuristic counterparts. We recommend using the SSEARCH algorithm combined with e-values for pairwise sequence comparisons.

On universal common ancestry, sequence similarity, and phylogenetic structure: the sins of P-values and the virtues of Bayesian evidence

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Theobald Douglas L

2011-11-01

Full Text Available Abstract Background The universal common ancestry (UCA of all known life is a fundamental component of modern evolutionary theory, supported by a wide range of qualitative molecular evidence. Nevertheless, recently both the status and nature of UCA has been questioned. In earlier work I presented a formal, quantitative test of UCA in which model selection criteria overwhelmingly choose common ancestry over independent ancestry, based on a dataset of universally conserved proteins. These model-based tests are founded in likelihoodist and Bayesian probability theory, in opposition to classical frequentist null hypothesis tests such as Karlin-Altschul E-values for sequence similarity. In a recent comment, Koonin and Wolf (K&W claim that the model preference for UCA is "a trivial consequence of significant sequence similarity". They support this claim with a computational simulation, derived from universally conserved proteins, which produces similar sequences lacking phylogenetic structure. The model selection tests prefer common ancestry for this artificial data set. Results For the real universal protein sequences, hierarchical phylogenetic structure (induced by genealogical history is the overriding reason for why the tests choose UCA; sequence similarity is a relatively minor factor. First, for cases of conflicting phylogenetic structure, the tests choose independent ancestry even with highly similar sequences. Second, certain models, like star trees and K&W's profile model (corresponding to their simulation, readily explain sequence similarity yet lack phylogenetic structure. However, these are extremely poor models for the real proteins, even worse than independent ancestry models, though they explain K&W's artificial data well. Finally, K&W's simulation is an implementation of a well-known phylogenetic model, and it produces sequences that mimic homologous proteins. Therefore the model selection tests work appropriately with the artificial

First-order and higher order sequence learning in specific language impairment.

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Clark, Gillian M; Lum, Jarrad A G

2017-02-01

A core claim of the procedural deficit hypothesis of specific language impairment (SLI) is that the disorder is associated with poor implicit sequence learning. This study investigated whether implicit sequence learning problems in SLI are present for first-order conditional (FOC) and higher order conditional (HOC) sequences. Twenty-five children with SLI and 27 age-matched, nonlanguage-impaired children completed 2 serial reaction time tasks. On 1 version, the sequence to be implicitly learnt comprised a FOC sequence and on the other a HOC sequence. Results showed that the SLI group learned the HOC sequence (η p ² = .285, p = .005) but not the FOC sequence (η p ² = .099, p = .118). The control group learned both sequences (FOC η p ² = .497, HOC η p 2= .465, ps < .001). The SLI group's difficulty learning the FOC sequence is consistent with the procedural deficit hypothesis. However, the study provides new evidence that multiple mechanisms may underpin the learning of FOC and HOC sequences. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Enzyme sequence similarity improves the reaction alignment method for cross-species pathway comparison

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Ovacik, Meric A. [Chemical and Biochemical Engineering Department, Rutgers University, Piscataway, NJ 08854 (United States); Androulakis, Ioannis P., E-mail: yannis@rci.rutgers.edu [Chemical and Biochemical Engineering Department, Rutgers University, Piscataway, NJ 08854 (United States); Biomedical Engineering Department, Rutgers University, Piscataway, NJ 08854 (United States)

2013-09-15

Pathway-based information has become an important source of information for both establishing evolutionary relationships and understanding the mode of action of a chemical or pharmaceutical among species. Cross-species comparison of pathways can address two broad questions: comparison in order to inform evolutionary relationships and to extrapolate species differences used in a number of different applications including drug and toxicity testing. Cross-species comparison of metabolic pathways is complex as there are multiple features of a pathway that can be modeled and compared. Among the various methods that have been proposed, reaction alignment has emerged as the most successful at predicting phylogenetic relationships based on NCBI taxonomy. We propose an improvement of the reaction alignment method by accounting for sequence similarity in addition to reaction alignment method. Using nine species, including human and some model organisms and test species, we evaluate the standard and improved comparison methods by analyzing glycolysis and citrate cycle pathways conservation. In addition, we demonstrate how organism comparison can be conducted by accounting for the cumulative information retrieved from nine pathways in central metabolism as well as a more complete study involving 36 pathways common in all nine species. Our results indicate that reaction alignment with enzyme sequence similarity results in a more accurate representation of pathway specific cross-species similarities and differences based on NCBI taxonomy.

Enzyme sequence similarity improves the reaction alignment method for cross-species pathway comparison

International Nuclear Information System (INIS)

Ovacik, Meric A.; Androulakis, Ioannis P.

2013-01-01

Pathway-based information has become an important source of information for both establishing evolutionary relationships and understanding the mode of action of a chemical or pharmaceutical among species. Cross-species comparison of pathways can address two broad questions: comparison in order to inform evolutionary relationships and to extrapolate species differences used in a number of different applications including drug and toxicity testing. Cross-species comparison of metabolic pathways is complex as there are multiple features of a pathway that can be modeled and compared. Among the various methods that have been proposed, reaction alignment has emerged as the most successful at predicting phylogenetic relationships based on NCBI taxonomy. We propose an improvement of the reaction alignment method by accounting for sequence similarity in addition to reaction alignment method. Using nine species, including human and some model organisms and test species, we evaluate the standard and improved comparison methods by analyzing glycolysis and citrate cycle pathways conservation. In addition, we demonstrate how organism comparison can be conducted by accounting for the cumulative information retrieved from nine pathways in central metabolism as well as a more complete study involving 36 pathways common in all nine species. Our results indicate that reaction alignment with enzyme sequence similarity results in a more accurate representation of pathway specific cross-species similarities and differences based on NCBI taxonomy

On the Power and Limits of Sequence Similarity Based Clustering of Proteins Into Families

DEFF Research Database (Denmark)

Wiwie, Christian; Röttger, Richard

2017-01-01

Over the last decades, we have observed an ongoing tremendous growth of available sequencing data fueled by the advancements in wet-lab technology. The sequencing information is only the beginning of the actual understanding of how organisms survive and prosper. It is, for instance, equally...... important to also unravel the proteomic repertoire of an organism. A classical computational approach for detecting protein families is a sequence-based similarity calculation coupled with a subsequent cluster analysis. In this work we have intensively analyzed various clustering tools on a large scale. We...... used the data to investigate the behavior of the tools' parameters underlining the diversity of the protein families. Furthermore, we trained regression models for predicting the expected performance of a clustering tool for an unknown data set and aimed to also suggest optimal parameters...

Detecting atypical examples of known domain types by sequence similarity searching: the SBASE domain library approach.

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Dhir, Somdutta; Pacurar, Mircea; Franklin, Dino; Gáspári, Zoltán; Kertész-Farkas, Attila; Kocsor, András; Eisenhaber, Frank; Pongor, Sándor

2010-11-01

SBASE is a project initiated to detect known domain types and predicting domain architectures using sequence similarity searching (Simon et al., Protein Seq Data Anal, 5: 39-42, 1992, Pongor et al, Nucl. Acids. Res. 21:3111-3115, 1992). The current approach uses a curated collection of domain sequences - the SBASE domain library - and standard similarity search algorithms, followed by postprocessing which is based on a simple statistics of the domain similarity network (http://hydra.icgeb.trieste.it/sbase/). It is especially useful in detecting rare, atypical examples of known domain types which are sometimes missed even by more sophisticated methodologies. This approach does not require multiple alignment or machine learning techniques, and can be a useful complement to other domain detection methodologies. This article gives an overview of the project history as well as of the concepts and principles developed within this the project.

Construction of a phylogenetic tree of photosynthetic prokaryotes based on average similarities of whole genome sequences.

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Soichirou Satoh

Full Text Available Phylogenetic trees have been constructed for a wide range of organisms using gene sequence information, especially through the identification of orthologous genes that have been vertically inherited. The number of available complete genome sequences is rapidly increasing, and many tools for construction of genome trees based on whole genome sequences have been proposed. However, development of a reasonable method of using complete genome sequences for construction of phylogenetic trees has not been established. We have developed a method for construction of phylogenetic trees based on the average sequence similarities of whole genome sequences. We used this method to examine the phylogeny of 115 photosynthetic prokaryotes, i.e., cyanobacteria, Chlorobi, proteobacteria, Chloroflexi, Firmicutes and nonphotosynthetic organisms including Archaea. Although the bootstrap values for the branching order of phyla were low, probably due to lateral gene transfer and saturated mutation, the obtained tree was largely consistent with the previously reported phylogenetic trees, indicating that this method is a robust alternative to traditional phylogenetic methods.

Phylogenetic similarity of the canine parvovirus wild-type isolates on the basis of VP1/VP2 gene fragment sequence analysis.

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Rypul, K; Chmielewski, R; Smielewska-Loś, E; Klimentowski, S

2002-04-01

Biological material was taken from dogs with diarrhoea. Faecal samples were taken from within live animals and intestinal tract fragments (i.e. small intestine, and stomach) were taken from dead animals. In total, 18 specimens were investigated from dogs housed alone or in large groups. To test for the presence of the virus, latex (On Site Biotech, Uppsala, Sweden) and direct immunofluorescence tests were performed. At the same time, polymerase chain reaction (PCR) with primers complementary to a conservative region of VP1/VP2 was carried out. The products of amplification were analysed on 2% agarose gel. The purified products were cloned with the Template Generation System (Finnzymes, Espoo, Finland) using a transposition reaction and positive clones were searched using the 'colony screening by PCR' method. The sequencing gave 12 sequences of VP1/VP2 gene fragments that were of high similarity. Among the 12 analysed sequences, six exhibited 88% similarity, four exhibited 100% similarity and two exhibited 71% similarity.

StralSV: assessment of sequence variability within similar 3D structures and application to polio RNA-dependent RNA polymerase

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Zemla, A; Lang, D; Kostova, T; Andino, R; Zhou, C

2010-11-29

Most of the currently used methods for protein function prediction rely on sequence-based comparisons between a query protein and those for which a functional annotation is provided. A serious limitation of sequence similarity-based approaches for identifying residue conservation among proteins is the low confidence in assigning residue-residue correspondences among proteins when the level of sequence identity between the compared proteins is poor. Multiple sequence alignment methods are more satisfactory - still, they cannot provide reliable results at low levels of sequence identity. Our goal in the current work was to develop an algorithm that could overcome these difficulties and facilitate the identification of structurally (and possibly functionally) relevant residue-residue correspondences between compared protein structures. Here we present StralSV, a new algorithm for detecting closely related structure fragments and quantifying residue frequency from tight local structure alignments. We apply StralSV in a study of the RNA-dependent RNA polymerase of poliovirus and demonstrate that the algorithm can be used to determine regions of the protein that are relatively unique or that shared structural similarity with structures that are distantly related. By quantifying residue frequencies among many residue-residue pairs extracted from local alignments, one can infer potential structural or functional importance of specific residues that are determined to be highly conserved or that deviate from a consensus. We further demonstrate that considerable detailed structural and phylogenetic information can be derived from StralSV analyses. StralSV is a new structure-based algorithm for identifying and aligning structure fragments that have similarity to a reference protein. StralSV analysis can be used to quantify residue-residue correspondences and identify residues that may be of particular structural or functional importance, as well as unusual or unexpected

Sequence diversity, cytotoxicity and antigenic similarities of the leukotoxin of isolates of Mannheimia species from mastitis in domestic sheep.

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Omaleki, Lida; Browning, Glenn F; Barber, Stuart R; Allen, Joanne L; Srikumaran, Subramaniam; Markham, Philip F

2014-11-07

Species within the genus Mannheimia are among the most important causes of ovine mastitis. Isolates of these species can express leukotoxin A (LktA), a primary virulence factor of these bacteria. To examine the significance of variation in the LktA, the sequences of the lktA genes in a panel of isolates from cases of ovine mastitis were compared. The cross-neutralising capacities of rat antisera raised against LktA of one Mannheimia glucosida, one haemolytic Mannheimia ruminalis, and two Mannheimia haemolytica isolates were also examined to assess the effect that variation in the lktA gene can have on protective immunity against leukotoxins with differing sequences. The lktA nucleotide distance between the M. haemolytica isolates was greater than between the M. glucosida isolates, with the M. haemolytica isolates divisible into two groups based on their lktA sequences. Comparison of the topology of phylogenetic trees of 16S rDNA and lktA sequences revealed differences in the relationships between some isolates, suggesting horizontal gene transfer. Cross neutralisation data obtained with monospecific anti-LktA rat sera were used to derive antigenic similarity coefficients for LktA from the four Mannheimia species isolates. Similarity coefficients indicated that LktA of the two M. haemolytica isolates were least similar, while LktA from M. glucosida was most similar to those for one of the M. haemolytica isolates and the haemolytic M. ruminalis isolate. The results suggested that vaccination with the M. glucosida leukotoxin would generate the greatest cross-protection against ovine mastitis caused by Mannheimia species with these alleles. Copyright © 2014 Elsevier B.V. All rights reserved.

Protein sequences and redox titrations indicate that the electron acceptors in reaction centers from heliobacteria are similar to Photosystem I

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Trost, J. T.; Brune, D. C.; Blankenship, R. E.

1992-01-01

Photosynthetic reaction centers isolated from Heliobacillus mobilis exhibit a single major protein on SDS-PAGE of 47 000 Mr. Attempts to sequence the reaction center polypeptide indicated that the N-terminus is blocked. After enzymatic and chemical cleavage, four peptide fragments were sequenced from the Heliobacillus mobilis apoprotein. Only one of these sequences showed significant specific similarity to any of the protein and deduced protein sequences in the GenBank data base. This fragment is identical with 56% of the residues, including both cysteines, found in highly conserved region that is proposed to bind iron-sulfur center Fx in the Photosystem I reaction center peptide that is the psaB gene product. The similarity to the psaA gene product in this region is 48%. Redox titrations of laser-flash-induced photobleaching with millisecond decay kinetics on isolated reaction centers from Heliobacterium gestii indicate a midpoint potential of -414 mV with n = 2 titration behavior. In membranes, the behavior is intermediate between n = 1 and n = 2, and the apparent midpoint potential is -444 mV. This is compared to the behavior in Photosystem I, where the intermediate electron acceptor A1, thought to be a phylloquinone molecule, has been proposed to undergo a double reduction at low redox potentials in the presence of viologen redox mediators. These results strongly suggest that the acceptor side electron transfer system in reaction centers from heliobacteria is indeed analogous to that found in Photosystem I. The sequence similarities indicate that the divergence of the heliobacteria from the Photosystem I line occurred before the gene duplication and subsequent divergence that lead to the heterodimeric protein core of the Photosystem I reaction center.

Statistical potential-based amino acid similarity matrices for aligning distantly related protein sequences.

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Tan, Yen Hock; Huang, He; Kihara, Daisuke

2006-08-15

Aligning distantly related protein sequences is a long-standing problem in bioinformatics, and a key for successful protein structure prediction. Its importance is increasing recently in the context of structural genomics projects because more and more experimentally solved structures are available as templates for protein structure modeling. Toward this end, recent structure prediction methods employ profile-profile alignments, and various ways of aligning two profiles have been developed. More fundamentally, a better amino acid similarity matrix can improve a profile itself; thereby resulting in more accurate profile-profile alignments. Here we have developed novel amino acid similarity matrices from knowledge-based amino acid contact potentials. Contact potentials are used because the contact propensity to the other amino acids would be one of the most conserved features of each position of a protein structure. The derived amino acid similarity matrices are tested on benchmark alignments at three different levels, namely, the family, the superfamily, and the fold level. Compared to BLOSUM45 and the other existing matrices, the contact potential-based matrices perform comparably in the family level alignments, but clearly outperform in the fold level alignments. The contact potential-based matrices perform even better when suboptimal alignments are considered. Comparing the matrices themselves with each other revealed that the contact potential-based matrices are very different from BLOSUM45 and the other matrices, indicating that they are located in a different basin in the amino acid similarity matrix space.

Bidirectional gene sequences with similar homology to functional proteins of alkane degrading bacterium pseudomonas fredriksbergensis DNA

International Nuclear Information System (INIS)

Megeed, A.A.

2011-01-01

The potential for two overlapping fragments of DNA from a clone of newly isolated alkanes degrading bacterium Pseudomonas frederiksbergensis encoding sequences with similar homology to two parts of functional proteins is described. One strand contains a sequence with high homology to alkanes monooxygenase (alkB), a member of the alkanes hydroxylase family, and the other strand contains a sequence with some homology to alcohol dehydrogenase gene (alkJ). Overlapping of the genes on opposite strands has been reported in eukaryotic species, and is now reported in a bacterial species. The sequence comparisons and ORFS results revealed that the regulation and the genes organization involved in alkane oxidation represented in Pseudomonas frederiksberghensis varies among the different known alkane degrading bacteria. The alk gene cluster containing homologues to the known alkane monooxygenase (alkB), and rubredoxin (alkG) are oriented in the same direction, whereas alcohol dehydrogenase (alkJ) is oriented in the opposite direction. Such genomes encode messages on both strands of the DNA, or in an overlapping but different reading frames, of the same strand of DNA. The possibility of creating novel genes from pre-existing sequences, known as overprinting, which is a widespread phenomenon in small viruses. Here, the origin and evolution of the gene overlap to bacteriophages belonging to the family Microviridae have been investigated. Such a phenomenon is most widely described in extremely small genomes such as those of viruses or small plasmids, yet here is a unique phenomenon. (author)

Simultaneous identification of long similar substrings in large sets of sequences

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Wittig Burghardt

2007-05-01

Full Text Available Abstract Background Sequence comparison faces new challenges today, with many complete genomes and large libraries of transcripts known. Gene annotation pipelines match these sequences in order to identify genes and their alternative splice forms. However, the software currently available cannot simultaneously compare sets of sequences as large as necessary especially if errors must be considered. Results We therefore present a new algorithm for the identification of almost perfectly matching substrings in very large sets of sequences. Its implementation, called ClustDB, is considerably faster and can handle 16 times more data than VMATCH, the most memory efficient exact program known today. ClustDB simultaneously generates large sets of exactly matching substrings of a given minimum length as seeds for a novel method of match extension with errors. It generates alignments of maximum length with a considered maximum number of errors within each overlapping window of a given size. Such alignments are not optimal in the usual sense but faster to calculate and often more appropriate than traditional alignments for genomic sequence comparisons, EST and full-length cDNA matching, and genomic sequence assembly. The method is used to check the overlaps and to reveal possible assembly errors for 1377 Medicago truncatula BAC-size sequences published at http://www.medicago.org/genome/assembly_table.php?chr=1. Conclusion The program ClustDB proves that window alignment is an efficient way to find long sequence sections of homogenous alignment quality, as expected in case of random errors, and to detect systematic errors resulting from sequence contaminations. Such inserts are systematically overlooked in long alignments controlled by only tuning penalties for mismatches and gaps. ClustDB is freely available for academic use.

Compression-based classification of biological sequences and structures via the Universal Similarity Metric: experimental assessment.

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Ferragina, Paolo; Giancarlo, Raffaele; Greco, Valentina; Manzini, Giovanni; Valiente, Gabriel

2007-07-13

Similarity of sequences is a key mathematical notion for Classification and Phylogenetic studies in Biology. It is currently primarily handled using alignments. However, the alignment methods seem inadequate for post-genomic studies since they do not scale well with data set size and they seem to be confined only to genomic and proteomic sequences. Therefore, alignment-free similarity measures are actively pursued. Among those, USM (Universal Similarity Metric) has gained prominence. It is based on the deep theory of Kolmogorov Complexity and universality is its most novel striking feature. Since it can only be approximated via data compression, USM is a methodology rather than a formula quantifying the similarity of two strings. Three approximations of USM are available, namely UCD (Universal Compression Dissimilarity), NCD (Normalized Compression Dissimilarity) and CD (Compression Dissimilarity). Their applicability and robustness is tested on various data sets yielding a first massive quantitative estimate that the USM methodology and its approximations are of value. Despite the rich theory developed around USM, its experimental assessment has limitations: only a few data compressors have been tested in conjunction with USM and mostly at a qualitative level, no comparison among UCD, NCD and CD is available and no comparison of USM with existing methods, both based on alignments and not, seems to be available. We experimentally test the USM methodology by using 25 compressors, all three of its known approximations and six data sets of relevance to Molecular Biology. This offers the first systematic and quantitative experimental assessment of this methodology, that naturally complements the many theoretical and the preliminary experimental results available. Moreover, we compare the USM methodology both with methods based on alignments and not. We may group our experiments into two sets. The first one, performed via ROC (Receiver Operating Curve) analysis, aims at

Compression-based classification of biological sequences and structures via the Universal Similarity Metric: experimental assessment

Directory of Open Access Journals (Sweden)

Manzini Giovanni

2007-07-01

Full Text Available Abstract Background Similarity of sequences is a key mathematical notion for Classification and Phylogenetic studies in Biology. It is currently primarily handled using alignments. However, the alignment methods seem inadequate for post-genomic studies since they do not scale well with data set size and they seem to be confined only to genomic and proteomic sequences. Therefore, alignment-free similarity measures are actively pursued. Among those, USM (Universal Similarity Metric has gained prominence. It is based on the deep theory of Kolmogorov Complexity and universality is its most novel striking feature. Since it can only be approximated via data compression, USM is a methodology rather than a formula quantifying the similarity of two strings. Three approximations of USM are available, namely UCD (Universal Compression Dissimilarity, NCD (Normalized Compression Dissimilarity and CD (Compression Dissimilarity. Their applicability and robustness is tested on various data sets yielding a first massive quantitative estimate that the USM methodology and its approximations are of value. Despite the rich theory developed around USM, its experimental assessment has limitations: only a few data compressors have been tested in conjunction with USM and mostly at a qualitative level, no comparison among UCD, NCD and CD is available and no comparison of USM with existing methods, both based on alignments and not, seems to be available. Results We experimentally test the USM methodology by using 25 compressors, all three of its known approximations and six data sets of relevance to Molecular Biology. This offers the first systematic and quantitative experimental assessment of this methodology, that naturally complements the many theoretical and the preliminary experimental results available. Moreover, we compare the USM methodology both with methods based on alignments and not. We may group our experiments into two sets. The first one, performed via ROC

Ultra-fast sequence clustering from similarity networks with SiLiX

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Duret Laurent

2011-04-01

Full Text Available Abstract Background The number of gene sequences that are available for comparative genomics approaches is increasing extremely quickly. A current challenge is to be able to handle this huge amount of sequences in order to build families of homologous sequences in a reasonable time. Results We present the software package SiLiX that implements a novel method which reconsiders single linkage clustering with a graph theoretical approach. A parallel version of the algorithms is also presented. As a demonstration of the ability of our software, we clustered more than 3 millions sequences from about 2 billion BLAST hits in 7 minutes, with a high clustering quality, both in terms of sensitivity and specificity. Conclusions Comparing state-of-the-art software, SiLiX presents the best up-to-date capabilities to face the problem of clustering large collections of sequences. SiLiX is freely available at http://lbbe.univ-lyon1.fr/SiLiX.

Domain similarity based orthology detection.

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Bitard-Feildel, Tristan; Kemena, Carsten; Greenwood, Jenny M; Bornberg-Bauer, Erich

2015-05-13

Orthologous protein detection software mostly uses pairwise comparisons of amino-acid sequences to assert whether two proteins are orthologous or not. Accordingly, when the number of sequences for comparison increases, the number of comparisons to compute grows in a quadratic order. A current challenge of bioinformatic research, especially when taking into account the increasing number of sequenced organisms available, is to make this ever-growing number of comparisons computationally feasible in a reasonable amount of time. We propose to speed up the detection of orthologous proteins by using strings of domains to characterize the proteins. We present two new protein similarity measures, a cosine and a maximal weight matching score based on domain content similarity, and new software, named porthoDom. The qualities of the cosine and the maximal weight matching similarity measures are compared against curated datasets. The measures show that domain content similarities are able to correctly group proteins into their families. Accordingly, the cosine similarity measure is used inside porthoDom, the wrapper developed for proteinortho. porthoDom makes use of domain content similarity measures to group proteins together before searching for orthologs. By using domains instead of amino acid sequences, the reduction of the search space decreases the computational complexity of an all-against-all sequence comparison. We demonstrate that representing and comparing proteins as strings of discrete domains, i.e. as a concatenation of their unique identifiers, allows a drastic simplification of search space. porthoDom has the advantage of speeding up orthology detection while maintaining a degree of accuracy similar to proteinortho. The implementation of porthoDom is released using python and C++ languages and is available under the GNU GPL licence 3 at http://www.bornberglab.org/pages/porthoda .

"Venom" of the slow loris: sequence similarity of prosimian skin gland protein and Fel d 1 cat allergen.

Science.gov (United States)

Krane, Sonja; Itagaki, Yasuhiro; Nakanishi, Koji; Weldon, Paul J

2003-02-01

Bites inflicted on humans by the slow loris (Nycticebus coucang), a prosimian from Indonesia, are painful and elicit anaphylaxis. Toxins from N. coucang are thought to originate in the brachial organ, a naked, gland-laden area of skin situated on the flexor surface of the arm that is licked during grooming. We isolated a major component of the brachial organ secretions from N. coucang, an approximately 18 kDa protein composed of two 70-90 amino-acid chains linked by one or more disulfide bonds. The N-termini of these peptide chains exhibit nearly 70% sequence similarity (37% identity, chain 1; 54% identity, chain 2) with the two chains of Fel d 1, the major allergen from the domestic cat (Felis catus). The extensive sequence similarity between the brachial organ component of N. coucang and the cat allergen suggests that they exhibit immunogenic cross-reactivity. This work clarifies the chemical nature of the brachial organ exudate and suggests a possible mode of action underlying the noxious effects of slow loris bites.

Assessing Analytical Similarity of Proposed Amgen Biosimilar ABP 501 to Adalimumab.

Science.gov (United States)

Liu, Jennifer; Eris, Tamer; Li, Cynthia; Cao, Shawn; Kuhns, Scott

2016-08-01

ABP 501 is being developed as a biosimilar to adalimumab. Comprehensive comparative analytical characterization studies have been conducted and completed. The objective of this study was to assess analytical similarity between ABP 501 and two adalimumab reference products (RPs), licensed by the United States Food and Drug Administration (adalimumab [US]) and authorized by the European Union (adalimumab [EU]), using state-of-the-art analytical methods. Comprehensive analytical characterization incorporating orthogonal analytical techniques was used to compare products. Physicochemical property comparisons comprised the primary structure related to amino acid sequence and post-translational modifications including glycans; higher-order structure; primary biological properties mediated by target and receptor binding; product-related substances and impurities; host-cell impurities; general properties of the finished drug product, including strength and formulation; subvisible and submicron particles and aggregates; and forced thermal degradation. ABP 501 had the same amino acid sequence and similar post-translational modification profiles compared with adalimumab RPs. Primary structure, higher-order structure, and biological activities were similar for the three products. Product-related size and charge variants and aggregate and particle levels were also similar. ABP 501 had very low residual host-cell protein and DNA. The finished ABP 501 drug product has the same strength with regard to protein concentration and fill volume as adalimumab RPs. ABP 501 and the RPs had a similar stability profile both in normal storage and thermal stress conditions. Based on the comprehensive analytical similarity assessment, ABP 501 was found to be similar to adalimumab with respect to physicochemical and biological properties.

SVM-Prot 2016: A Web-Server for Machine Learning Prediction of Protein Functional Families from Sequence Irrespective of Similarity.

Science.gov (United States)

Li, Ying Hong; Xu, Jing Yu; Tao, Lin; Li, Xiao Feng; Li, Shuang; Zeng, Xian; Chen, Shang Ying; Zhang, Peng; Qin, Chu; Zhang, Cheng; Chen, Zhe; Zhu, Feng; Chen, Yu Zong

2016-01-01

Knowledge of protein function is important for biological, medical and therapeutic studies, but many proteins are still unknown in function. There is a need for more improved functional prediction methods. Our SVM-Prot web-server employed a machine learning method for predicting protein functional families from protein sequences irrespective of similarity, which complemented those similarity-based and other methods in predicting diverse classes of proteins including the distantly-related proteins and homologous proteins of different functions. Since its publication in 2003, we made major improvements to SVM-Prot with (1) expanded coverage from 54 to 192 functional families, (2) more diverse protein descriptors protein representation, (3) improved predictive performances due to the use of more enriched training datasets and more variety of protein descriptors, (4) newly integrated BLAST analysis option for assessing proteins in the SVM-Prot predicted functional families that were similar in sequence to a query protein, and (5) newly added batch submission option for supporting the classification of multiple proteins. Moreover, 2 more machine learning approaches, K nearest neighbor and probabilistic neural networks, were added for facilitating collective assessment of protein functions by multiple methods. SVM-Prot can be accessed at http://bidd2.nus.edu.sg/cgi-bin/svmprot/svmprot.cgi.

Defining reference sequences for Nocardia species by similarity and clustering analyses of 16S rRNA gene sequence data.

Directory of Open Access Journals (Sweden)

Manal Helal

Full Text Available BACKGROUND: The intra- and inter-species genetic diversity of bacteria and the absence of 'reference', or the most representative, sequences of individual species present a significant challenge for sequence-based identification. The aims of this study were to determine the utility, and compare the performance of several clustering and classification algorithms to identify the species of 364 sequences of 16S rRNA gene with a defined species in GenBank, and 110 sequences of 16S rRNA gene with no defined species, all within the genus Nocardia. METHODS: A total of 364 16S rRNA gene sequences of Nocardia species were studied. In addition, 110 16S rRNA gene sequences assigned only to the Nocardia genus level at the time of submission to GenBank were used for machine learning classification experiments. Different clustering algorithms were compared with a novel algorithm or the linear mapping (LM of the distance matrix. Principal Components Analysis was used for the dimensionality reduction and visualization. RESULTS: The LM algorithm achieved the highest performance and classified the set of 364 16S rRNA sequences into 80 clusters, the majority of which (83.52% corresponded with the original species. The most representative 16S rRNA sequences for individual Nocardia species have been identified as 'centroids' in respective clusters from which the distances to all other sequences were minimized; 110 16S rRNA gene sequences with identifications recorded only at the genus level were classified using machine learning methods. Simple kNN machine learning demonstrated the highest performance and classified Nocardia species sequences with an accuracy of 92.7% and a mean frequency of 0.578. CONCLUSION: The identification of centroids of 16S rRNA gene sequence clusters using novel distance matrix clustering enables the identification of the most representative sequences for each individual species of Nocardia and allows the quantitation of inter- and intra

A space-efficient algorithm for local similarities.

Science.gov (United States)

Huang, X Q; Hardison, R C; Miller, W

1990-10-01

Existing dynamic-programming algorithms for identifying similar regions of two sequences require time and space proportional to the product of the sequence lengths. Often this space requirement is more limiting than the time requirement. We describe a dynamic-programming local-similarity algorithm that needs only space proportional to the sum of the sequence lengths. The method can also find repeats within a single long sequence. To illustrate the algorithm's potential, we discuss comparison of a 73,360 nucleotide sequence containing the human beta-like globin gene cluster and a corresponding 44,594 nucleotide sequence for rabbit, a problem well beyond the capabilities of other dynamic-programming software.

Fold-recognition and comparative modeling of human α2,3-sialyltransferases reveal their sequence and structural similarities to CstII from Campylobacter jejuni

Directory of Open Access Journals (Sweden)

Balaji Petety V

2006-04-01

Full Text Available Abstract Background The 3-D structure of none of the eukaryotic sialyltransferases (SiaTs has been determined so far. Sequence alignment algorithms such as BLAST and PSI-BLAST could not detect a homolog of these enzymes from the protein databank. SiaTs, thus, belong to the hard/medium target category in the CASP experiments. The objective of the current work is to model the 3-D structures of human SiaTs which transfer the sialic acid in α2,3-linkage viz., ST3Gal I, II, III, IV, V, and VI, using fold-recognition and comparative modeling methods. The pair-wise sequence similarity among these six enzymes ranges from 41 to 63%. Results Unlike the sequence similarity servers, fold-recognition servers identified CstII, a α2,3/8 dual-activity SiaT from Campylobacter jejuni as the homolog of all the six ST3Gals; the level of sequence similarity between CstII and ST3Gals is only 15–20% and the similarity is restricted to well-characterized motif regions of ST3Gals. Deriving template-target sequence alignments for the entire ST3Gal sequence was not straightforward: the fold-recognition servers could not find a template for the region preceding the L-motif and that between the L- and S-motifs. Multiple structural templates were identified to model these regions and template identification-modeling-evaluation had to be performed iteratively to choose the most appropriate templates. The modeled structures have acceptable stereochemical properties and are also able to provide qualitative rationalizations for some of the site-directed mutagenesis results reported in literature. Apart from the predicted models, an unexpected but valuable finding from this study is the sequential and structural relatedness of family GT42 and family GT29 SiaTs. Conclusion The modeled 3-D structures can be used for docking and other modeling studies and for the rational identification of residues to be mutated to impart desired properties such as altered stability, substrate

Musicians' and nonmusicians' short-term memory for verbal and musical sequences: comparing phonological similarity and pitch proximity.

Science.gov (United States)

Williamson, Victoria J; Baddeley, Alan D; Hitch, Graham J

2010-03-01

Language-music comparative studies have highlighted the potential for shared resources or neural overlap in auditory short-term memory. However, there is a lack of behavioral methodologies for comparing verbal and musical serial recall. We developed a visual grid response that allowed both musicians and nonmusicians to perform serial recall of letter and tone sequences. The new method was used to compare the phonological similarity effect with the impact of an operationalized musical equivalent-pitch proximity. Over the course of three experiments, we found that short-term memory for tones had several similarities to verbal memory, including limited capacity and a significant effect of pitch proximity in nonmusicians. Despite being vulnerable to phonological similarity when recalling letters, however, musicians showed no effect of pitch proximity, a result that we suggest might reflect strategy differences. Overall, the findings support a limited degree of correspondence in the way that verbal and musical sounds are processed in auditory short-term memory.

Analysis of HIV-1 intersubtype recombination breakpoints suggests region with high pairing probability may be a more fundamental factor than sequence similarity affecting HIV-1 recombination.

Science.gov (United States)

Jia, Lei; Li, Lin; Gui, Tao; Liu, Siyang; Li, Hanping; Han, Jingwan; Guo, Wei; Liu, Yongjian; Li, Jingyun

2016-09-21

With increasing data on HIV-1, a more relevant molecular model describing mechanism details of HIV-1 genetic recombination usually requires upgrades. Currently an incomplete structural understanding of the copy choice mechanism along with several other issues in the field that lack elucidation led us to perform an analysis of the correlation between breakpoint distributions and (1) the probability of base pairing, and (2) intersubtype genetic similarity to further explore structural mechanisms. Near full length sequences of URFs from Asia, Europe, and Africa (one sequence/patient), and representative sequences of worldwide CRFs were retrieved from the Los Alamos HIV database. Their recombination patterns were analyzed by jpHMM in detail. Then the relationships between breakpoint distributions and (1) the probability of base pairing, and (2) intersubtype genetic similarities were investigated. Pearson correlation test showed that all URF groups and the CRF group exhibit the same breakpoint distribution pattern. Additionally, the Wilcoxon two-sample test indicated a significant and inexplicable limitation of recombination in regions with high pairing probability. These regions have been found to be strongly conserved across distinct biological states (i.e., strong intersubtype similarity), and genetic similarity has been determined to be a very important factor promoting recombination. Thus, the results revealed an unexpected disagreement between intersubtype similarity and breakpoint distribution, which were further confirmed by genetic similarity analysis. Our analysis reveals a critical conflict between results from natural HIV-1 isolates and those from HIV-1-based assay vectors in which genetic similarity has been shown to be a very critical factor promoting recombination. These results indicate the region with high-pairing probabilities may be a more fundamental factor affecting HIV-1 recombination than sequence similarity in natural HIV-1 infections. Our

Judgments of brand similarity

NARCIS (Netherlands)

Bijmolt, THA; Wedel, M; Pieters, RGM; DeSarbo, WS

This paper provides empirical insight into the way consumers make pairwise similarity judgments between brands, and how familiarity with the brands, serial position of the pair in a sequence, and the presentation format affect these judgments. Within the similarity judgment process both the

An alignment-free method to find similarity among protein sequences via the general form of Chou's pseudo amino acid composition.

Science.gov (United States)

Gupta, M K; Niyogi, R; Misra, M

2013-01-01

In this paper, we propose a method to create the 60-dimensional feature vector for protein sequences via the general form of pseudo amino acid composition. The construction of the feature vector is based on the contents of amino acids, total distance of each amino acid from the first amino acid in the protein sequence and the distribution of 20 amino acids. The obtained cosine distance metric (also called the similarity matrix) is used to construct the phylogenetic tree by the neighbour joining method. In order to show the applicability of our approach, we tested it on three proteins: 1) ND5 protein sequences from nine species, 2) ND6 protein sequences from eight species, and 3) 50 coronavirus spike proteins. The results are in agreement with known history and the output from the multiple sequence alignment program ClustalW, which is widely used. We have also compared our phylogenetic results with six other recently proposed alignment-free methods. These comparisons show that our proposed method gives a more consistent biological relationship than the others. In addition, the time complexity is linear and space required is less as compared with other alignment-free methods that use graphical representation. It should be noted that the multiple sequence alignment method has exponential time complexity.

An effective approach for annotation of protein families with low sequence similarity and conserved motifs: identifying GDSL hydrolases across the plant kingdom.

Science.gov (United States)

Vujaklija, Ivan; Bielen, Ana; Paradžik, Tina; Biđin, Siniša; Goldstein, Pavle; Vujaklija, Dušica

2016-02-18

The massive accumulation of protein sequences arising from the rapid development of high-throughput sequencing, coupled with automatic annotation, results in high levels of incorrect annotations. In this study, we describe an approach to decrease annotation errors of protein families characterized by low overall sequence similarity. The GDSL lipolytic family comprises proteins with multifunctional properties and high potential for pharmaceutical and industrial applications. The number of proteins assigned to this family has increased rapidly over the last few years. In particular, the natural abundance of GDSL enzymes reported recently in plants indicates that they could be a good source of novel GDSL enzymes. We noticed that a significant proportion of annotated sequences lack specific GDSL motif(s) or catalytic residue(s). Here, we applied motif-based sequence analyses to identify enzymes possessing conserved GDSL motifs in selected proteomes across the plant kingdom. Motif-based HMM scanning (Viterbi decoding-VD and posterior decoding-PD) and the here described PD/VD protocol were successfully applied on 12 selected plant proteomes to identify sequences with GDSL motifs. A significant number of identified GDSL sequences were novel. Moreover, our scanning approach successfully detected protein sequences lacking at least one of the essential motifs (171/820) annotated by Pfam profile search (PfamA) as GDSL. Based on these analyses we provide a curated list of GDSL enzymes from the selected plants. CLANS clustering and phylogenetic analysis helped us to gain a better insight into the evolutionary relationship of all identified GDSL sequences. Three novel GDSL subfamilies as well as unreported variations in GDSL motifs were discovered in this study. In addition, analyses of selected proteomes showed a remarkable expansion of GDSL enzymes in the lycophyte, Selaginella moellendorffii. Finally, we provide a general motif-HMM scanner which is easily accessible through

Clustering and visualizing similarity networks of membrane proteins.

Science.gov (United States)

Hu, Geng-Ming; Mai, Te-Lun; Chen, Chi-Ming

2015-08-01

We proposed a fast and unsupervised clustering method, minimum span clustering (MSC), for analyzing the sequence-structure-function relationship of biological networks, and demonstrated its validity in clustering the sequence/structure similarity networks (SSN) of 682 membrane protein (MP) chains. The MSC clustering of MPs based on their sequence information was found to be consistent with their tertiary structures and functions. For the largest seven clusters predicted by MSC, the consistency in chain function within the same cluster is found to be 100%. From analyzing the edge distribution of SSN for MPs, we found a characteristic threshold distance for the boundary between clusters, over which SSN of MPs could be properly clustered by an unsupervised sparsification of the network distance matrix. The clustering results of MPs from both MSC and the unsupervised sparsification methods are consistent with each other, and have high intracluster similarity and low intercluster similarity in sequence, structure, and function. Our study showed a strong sequence-structure-function relationship of MPs. We discussed evidence of convergent evolution of MPs and suggested applications in finding structural similarities and predicting biological functions of MP chains based on their sequence information. © 2015 Wiley Periodicals, Inc.

GROUPING WEB ACCESS SEQUENCES uSING SEQUENCE ALIGNMENT METHOD

OpenAIRE

BHUPENDRA S CHORDIA; KRISHNAKANT P ADHIYA

2011-01-01

In web usage mining grouping of web access sequences can be used to determine the behavior or intent of a set of users. Grouping websessions is how to measure the similarity between web sessions. There are many shortcomings in traditional measurement methods. The taskof grouping web sessions based on similarity and consists of maximizing the intra-group similarity while minimizing the inter-groupsimilarity is done using sequence alignment method. This paper introduces a new method to group we...

Pythoscape: a framework for generation of large protein similarity networks.

Science.gov (United States)

Barber, Alan E; Babbitt, Patricia C

2012-11-01

Pythoscape is a framework implemented in Python for processing large protein similarity networks for visualization in other software packages. Protein similarity networks are graphical representations of sequence, structural and other similarities among proteins for which pairwise all-by-all similarity connections have been calculated. Mapping of biological and other information to network nodes or edges enables hypothesis creation about sequence-structure-function relationships across sets of related proteins. Pythoscape provides several options to calculate pairwise similarities for input sequences or structures, applies filters to network edges and defines sets of similar nodes and their associated data as single nodes (termed representative nodes) for compression of network information and output data or formatted files for visualization.

Sequencing of the needle transcriptome from Norway spruce (Picea abies Karst L. reveals lower substitution rates, but similar selective constraints in gymnosperms and angiosperms

Directory of Open Access Journals (Sweden)

Chen Jun

2012-11-01

Full Text Available Abstract Background A detailed knowledge about spatial and temporal gene expression is important for understanding both the function of genes and their evolution. For the vast majority of species, transcriptomes are still largely uncharacterized and even in those where substantial information is available it is often in the form of partially sequenced transcriptomes. With the development of next generation sequencing, a single experiment can now simultaneously identify the transcribed part of a species genome and estimate levels of gene expression. Results mRNA from actively growing needles of Norway spruce (Picea abies was sequenced using next generation sequencing technology. In total, close to 70 million fragments with a length of 76 bp were sequenced resulting in 5 Gbp of raw data. A de novo assembly of these reads, together with publicly available expressed sequence tag (EST data from Norway spruce, was used to create a reference transcriptome. Of the 38,419 PUTs (putative unique transcripts longer than 150 bp in this reference assembly, 83.5% show similarity to ESTs from other spruce species and of the remaining PUTs, 3,704 show similarity to protein sequences from other plant species, leaving 4,167 PUTs with limited similarity to currently available plant proteins. By predicting coding frames and comparing not only the Norway spruce PUTs, but also PUTs from the close relatives Picea glauca and Picea sitchensis to both Pinus taeda and Taxus mairei, we obtained estimates of synonymous and non-synonymous divergence among conifer species. In addition, we detected close to 15,000 SNPs of high quality and estimated gene expression differences between samples collected under dark and light conditions. Conclusions Our study yielded a large number of single nucleotide polymorphisms as well as estimates of gene expression on transcriptome scale. In agreement with a recent study we find that the synonymous substitution rate per year (0.6 × 10�

Human Treponema pallidum 11q/j isolate belongs to subsp. endemicum but contains two loci with a sequence in TP0548 and TP0488 similar to subsp. pertenue and subsp. pallidum, respectively.

Directory of Open Access Journals (Sweden)

Lenka Mikalová

2017-03-01

Full Text Available Treponema pallidum subsp. endemicum (TEN is the causative agent of endemic syphilis (bejel. An unusual human TEN 11q/j isolate was obtained from a syphilis-like primary genital lesion from a patient that returned to France from Pakistan.The TEN 11q/j isolate was characterized using nested PCR followed by Sanger sequencing and/or direct Illumina sequencing. Altogether, 44 chromosomal regions were analyzed. Overall, the 11q/j isolate clustered with TEN strains Bosnia A and Iraq B as expected from previous TEN classification of the 11q/j isolate. However, the 11q/j sequence in a 505 bp-long region at the TP0488 locus was similar to Treponema pallidum subsp. pallidum (TPA strains, but not to TEN Bosnia A and Iraq B sequences, suggesting a recombination event at this locus. Similarly, the 11q/j sequence in a 613 bp-long region at the TP0548 locus was similar to Treponema pallidum subsp. pertenue (TPE strains, but not to TEN sequences.A detailed analysis of two recombinant loci found in the 11q/j clinical isolate revealed that the recombination event occurred just once, in the TP0488, with the donor sequence originating from a TPA strain. Since TEN Bosnia A and Iraq B were found to contain TPA-like sequences at the TP0548 locus, the recombination at TP0548 took place in a treponeme that was an ancestor to both TEN Bosnia A and Iraq B. The sequence of 11q/j isolate in TP0548 represents an ancestral TEN sequence that is similar to yaws-causing treponemes. In addition to the importance of the 11q/j isolate for reconstruction of the TEN phylogeny, this case emphasizes the possible role of TEN strains in development of syphilis-like lesions.

Is the phonological similarity effect in working memory due to proactive interference?

Science.gov (United States)

Baddeley, Alan D; Hitch, Graham J; Quinlan, Philip T

2018-04-12

Immediate serial recall of verbal material is highly sensitive to impairment attributable to phonological similarity. Although this has traditionally been interpreted as a within-sequence similarity effect, Engle (2007) proposed an interpretation based on interference from prior sequences, a phenomenon analogous to that found in the Peterson short-term memory (STM) task. We use the method of serial reconstruction to test this in an experiment contrasting the standard paradigm in which successive sequences are drawn from the same set of phonologically similar or dissimilar words and one in which the vowel sound on which similarity is based is switched from trial to trial, a manipulation analogous to that producing release from PI in the Peterson task. A substantial similarity effect occurs under both conditions although there is a small advantage from switching across similar sequences. There is, however, no evidence for the suggestion that the similarity effect will be absent from the very first sequence tested. Our results support the within-sequence similarity rather than a between-list PI interpretation. Reasons for the contrast with the classic Peterson short-term forgetting task are briefly discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Repdigits in k-Lucas sequences

Indian Academy of Sciences (India)

57(2) 2000 243-254) proved that 11 is the largest number with only one distinct digit (the so-called repdigit) in the sequence ( L n ( 2 ) ) n . In this paper, we address a similar problem in the family of -Lucas sequences. We also show that the -Lucas sequences have similar properties to those of -Fibonacci sequences ...

Similarity of eigenstates in generalized labyrinth tilings

International Nuclear Information System (INIS)

Thiem, Stefanie; Schreiber, Michael

2010-01-01

The eigenstates of d-dimensional quasicrystalline models with a separable Hamiltonian are studied within the tight-binding model. The approach is based on mathematical sequences, constructed by an inflation rule P = {w → s,s → sws b-1 } describing the weak/strong couplings of atoms in a quasiperiodic chain. Higher-dimensional quasiperiodic tilings are constructed as a direct product of these chains and their eigenstates can be directly calculated by multiplying the energies E or wave functions ψ of the chain, respectively. Applying this construction rule, the grid in d dimensions splits into 2 d-1 different tilings, for which we investigated the characteristics of the wave functions. For the standard two-dimensional labyrinth tiling constructed from the octonacci sequence (b = 2) the lattice breaks up into two identical lattices, which consequently yield the same eigenstates. While this is not the case for b ≠ 2, our numerical results show that the wave functions of the different grids become increasingly similar for large system sizes. This can be explained by the fact that the structure of the 2 d-1 grids mainly differs at the boundaries and thus for large systems the eigenstates approach each other. This property allows us to analytically derive properties of the higher-dimensional generalized labyrinth tilings from the one-dimensional results. In particular participation numbers and corresponding scaling exponents have been determined.

Isolation of laccase gene-specific sequences from white rot and brown rot fungi by PCR.

Science.gov (United States)

D'Souza, T M; Boominathan, K; Reddy, C A

1996-01-01

Degenerate primers corresponding to the consensus sequences of the copper-binding regions in the N-terminal domains of known basidiomycete laccases were used to isolate laccase gene-specific sequences from strains representing nine genera of wood rot fungi. All except three gave the expected PCR product of about 200 bp. Computer searches of the databases identified the sequence of each of the PCR products analyzed as a laccase gene sequence, suggesting the specificity of the primers. PCR products of the white rot fungi Ganoderma lucidum, Phlebia brevispora, and Trametes versicolor showed 65 to 74% nucleotide sequence similarity to each other; the similarity in deduced amino acid sequences was 83 to 91%. The PCR products of Lentinula edodes and Lentinus tigrinus, on the other hand, showed relatively low nucleotide and amino acid similarities (58 to 64 and 62 to 81%, respectively); however, these similarities were still much higher than when compared with the corresponding regions in the laccases of the ascomycete fungi Aspergillus nidulans and Neurospora crassa. A few of the white rot fungi, as well as Gloeophyllum trabeum, a brown rot fungus, gave a 144-bp PCR fragment which had a nucleotide sequence similarity of 60 to 71%. Demonstration of laccase activity in G. trabeum and several other brown rot fungi was of particular interest because these organisms were not previously shown to produce laccases. PMID:8837429

Subset of Kappa and Lambda Germline Sequences Result in Light Chains with a Higher Molecular Mass Phenotype.

Science.gov (United States)

Barnidge, David R; Lundström, Susanna L; Zhang, Bo; Dasari, Surendra; Murray, David L; Zubarev, Roman A

2015-12-04

In our previous work, we showed that electrospray ionization of intact polyclonal kappa and lambda light chains isolated from normal serum generates two distinct, Gaussian-shaped, molecular mass distributions representing the light-chain repertoire. During the analysis of a large (>100) patient sample set, we noticed a low-intensity molecular mass distribution with a mean of approximately 24 250 Da, roughly 800 Da higher than the mean of the typical kappa molecular-mass distribution mean of 23 450 Da. We also observed distinct clones in this region that did not appear to contain any typical post-translational modifications that would account for such a large mass shift. To determine the origin of the high molecular mass clones, we performed de novo bottom-up mass spectrometry on a purified IgM monoclonal light chain that had a calculated molecular mass of 24 275.03 Da. The entire sequence of the monoclonal light chain was determined using multienzyme digestion and de novo sequence-alignment software and was found to belong to the germline allele IGKV2-30. The alignment of kappa germline sequences revealed ten IGKV2 and one IGKV4 sequences that contained additional amino acids in their CDR1 region, creating the high-molecular-mass phenotype. We also performed an alignment of lambda germline sequences, which showed additional amino acids in the CDR2 region, and the FR3 region of functional germline sequences that result in a high-molecular-mass phenotype. The work presented here illustrates the ability of mass spectrometry to provide information on the diversity of light-chain molecular mass phenotypes in circulation, which reflects the germline sequences selected by the immunoglobulin-secreting B-cell population.

Similar Ratios of Introns to Intergenic Sequence across Animal Genomes.

Science.gov (United States)

Francis, Warren R; Wörheide, Gert

2017-06-01

One central goal of genome biology is to understand how the usage of the genome differs between organisms. Our knowledge of genome composition, needed for downstream inferences, is critically dependent on gene annotations, yet problems associated with gene annotation and assembly errors are usually ignored in comparative genomics. Here, we analyze the genomes of 68 species across 12 animal phyla and some single-cell eukaryotes for general trends in genome composition and transcription, taking into account problems of gene annotation. We show that, regardless of genome size, the ratio of introns to intergenic sequence is comparable across essentially all animals, with nearly all deviations dominated by increased intergenic sequence. Genomes of model organisms have ratios much closer to 1:1, suggesting that the majority of published genomes of nonmodel organisms are underannotated and consequently omit substantial numbers of genes, with likely negative impact on evolutionary interpretations. Finally, our results also indicate that most animals transcribe half or more of their genomes arguing against differences in genome usage between animal groups, and also suggesting that the transcribed portion is more dependent on genome size than previously thought. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

A Novel Phytase with Sequence Similarity to Purple Acid Phosphatases Is Expressed in Cotyledons of Germinating Soybean Seedlings 1

Science.gov (United States)

Hegeman, Carla E.; Grabau, Elizabeth A.

2001-01-01

Phytic acid (myo-inositol hexakisphosphate) is the major storage form of phosphorus in plant seeds. During germination, stored reserves are used as a source of nutrients by the plant seedling. Phytic acid is degraded by the activity of phytases to yield inositol and free phosphate. Due to the lack of phytases in the non-ruminant digestive tract, monogastric animals cannot utilize dietary phytic acid and it is excreted into manure. High phytic acid content in manure results in elevated phosphorus levels in soil and water and accompanying environmental concerns. The use of phytases to degrade seed phytic acid has potential for reducing the negative environmental impact of livestock production. A phytase was purified to electrophoretic homogeneity from cotyledons of germinated soybeans (Glycine max L. Merr.). Peptide sequence data generated from the purified enzyme facilitated the cloning of the phytase sequence (GmPhy) employing a polymerase chain reaction strategy. The introduction of GmPhy into soybean tissue culture resulted in increased phytase activity in transformed cells, which confirmed the identity of the phytase gene. It is surprising that the soybean phytase was unrelated to previously characterized microbial or maize (Zea mays) phytases, which were classified as histidine acid phosphatases. The soybean phytase sequence exhibited a high degree of similarity to purple acid phosphatases, a class of metallophosphoesterases. PMID:11500558

Method and apparatus for biological sequence comparison

Science.gov (United States)

Marr, T.G.; Chang, W.I.

1997-12-23

A method and apparatus are disclosed for comparing biological sequences from a known source of sequences, with a subject (query) sequence. The apparatus takes as input a set of target similarity levels (such as evolutionary distances in units of PAM), and finds all fragments of known sequences that are similar to the subject sequence at each target similarity level, and are long enough to be statistically significant. The invention device filters out fragments from the known sequences that are too short, or have a lower average similarity to the subject sequence than is required by each target similarity level. The subject sequence is then compared only to the remaining known sequences to find the best matches. The filtering member divides the subject sequence into overlapping blocks, each block being sufficiently large to contain a minimum-length alignment from a known sequence. For each block, the filter member compares the block with every possible short fragment in the known sequences and determines a best match for each comparison. The determined set of short fragment best matches for the block provide an upper threshold on alignment values. Regions of a certain length from the known sequences that have a mean alignment value upper threshold greater than a target unit score are concatenated to form a union. The current block is compared to the union and provides an indication of best local alignment with the subject sequence. 5 figs.

The genomic sequence of cowpea aphid-borne mosaic virus and its similarities with other potyviruses

NARCIS (Netherlands)

Mlotshwa, S.; Verver, J.; Sithole-Niang, I.; Kampen, van T.; Kammen, van A.; Wellink, J.

2002-01-01

The genomic sequence of a Zimbabwe isolate of Cowpea aphid-borne mosaic virus (CABMV-Z) was determined by sequencing overlapping viral cDNA clones generated by RT-PCR using degenerate and/or specific primers. The sequence is 9465 nucleotides in length excluding the 3' terminal poly (A) tail and

Scaling Relations of Local Magnitude versus Moment Magnitude for Sequences of Similar Earthquakes in Switzerland

KAUST Repository

Bethmann, F.

2011-03-22

Theoretical considerations and empirical regressions show that, in the magnitude range between 3 and 5, local magnitude, ML, and moment magnitude, Mw, scale 1:1. Previous studies suggest that for smaller magnitudes this 1:1 scaling breaks down. However, the scatter between ML and Mw at small magnitudes is usually large and the resulting scaling relations are therefore uncertain. In an attempt to reduce these uncertainties, we first analyze the ML versus Mw relation based on 195 events, induced by the stimulation of a geothermal reservoir below the city of Basel, Switzerland. Values of ML range from 0.7 to 3.4. From these data we derive a scaling of ML ~ 1:5Mw over the given magnitude range. We then compare peak Wood-Anderson amplitudes to the low-frequency plateau of the displacement spectra for six sequences of similar earthquakes in Switzerland in the range of 0:5 ≤ ML ≤ 4:1. Because effects due to the radiation pattern and to the propagation path between source and receiver are nearly identical at a particular station for all events in a given sequence, the scatter in the data is substantially reduced. Again we obtain a scaling equivalent to ML ~ 1:5Mw. Based on simulations using synthetic source time functions for different magnitudes and Q values estimated from spectral ratios between downhole and surface recordings, we conclude that the observed scaling can be explained by attenuation and scattering along the path. Other effects that could explain the observed magnitude scaling, such as a possible systematic increase of stress drop or rupture velocity with moment magnitude, are masked by attenuation along the path.

Similarity as an organising principle in short-term memory.

Science.gov (United States)

LeCompte, D C; Watkins, M J

1993-03-01

The role of stimulus similarity as an organising principle in short-term memory was explored in a series of seven experiments. Each experiment involved the presentation of a short sequence of items that were drawn from two distinct physical classes and arranged such that item class changed after every second item. Following presentation, one item was re-presented as a probe for the 'target' item that had directly followed it in the sequence. Memory for the sequence was considered organised by class if probability of recall was higher when the probe and target were from the same class than when they were from different classes. Such organisation was found when one class was auditory and the other was visual (spoken vs. written words, and sounds vs. pictures). It was also found when both classes were auditory (words spoken in a male voice vs. words spoken in a female voice) and when both classes were visual (digits shown in one location vs. digits shown in another). It is concluded that short-term memory can be organised on the basis of sensory modality and on the basis of certain features within both the auditory and visual modalities.

Isolation of laccase gene-specific sequences from white rot and brown rot fungi by PCR

Energy Technology Data Exchange (ETDEWEB)

D`Souza, T.M.; Boominathan, K.; Reddy, C.A. [Michigan State Univ., East Lansing, MI (United States)

1996-10-01

Degenerate primers corresponding to the consensus sequences of the copper-binding regions in the N-terminal domains of known basidiomycete laccases were used to isolate laccase gene-specific sequences from strains representing nine genera of wood rot fungi. All except three gave the expected PCR product of about 200 bp. Computer searches of the databases identified the sequences of each of the PCR product of about 200 bp. Computer searches of the databases identified the sequence of each of the PCR products analyzed as a laccase gene sequence, suggesting the specificity of the primers. PCR products of the white rot fungi Ganoderma lucidum, Phlebia brevispora, and Trametes versicolor showed 65 to 74% nucleotide sequence similarity to each other; the similarity in deduced amino acid sequences was 83 to 91%. The PCR products of Lentinula edodes and Lentinus tigrinus, on the other hand, showed relatively low nucleotide and amino acid similarities (58 to 64 and 62 to 81%, respectively); however, these similarities were still much higher than when compared with the corresponding regions in the laccases of the ascomycete fungi Aspergillus nidulans and Neurospora crassa. A few of the white rot fungi, as well as Gloeophyllum trabeum, a brown rot fungus, gave a 144-bp PCR fragment which had a nucleotide sequence similarity of 60 to 71%. Demonstration of laccase activity in G. trabeum and several other brown rot fungi was of particular interest because these organisms were not previously shown to produce laccases. 36 refs., 6 figs., 2 tabs.

Protein structural similarity search by Ramachandran codes

Directory of Open Access Journals (Sweden)

Chang Chih-Hung

2007-08-01

Full Text Available Abstract Background Protein structural data has increased exponentially, such that fast and accurate tools are necessary to access structure similarity search. To improve the search speed, several methods have been designed to reduce three-dimensional protein structures to one-dimensional text strings that are then analyzed by traditional sequence alignment methods; however, the accuracy is usually sacrificed and the speed is still unable to match sequence similarity search tools. Here, we aimed to improve the linear encoding methodology and develop efficient search tools that can rapidly retrieve structural homologs from large protein databases. Results We propose a new linear encoding method, SARST (Structural similarity search Aided by Ramachandran Sequential Transformation. SARST transforms protein structures into text strings through a Ramachandran map organized by nearest-neighbor clustering and uses a regenerative approach to produce substitution matrices. Then, classical sequence similarity search methods can be applied to the structural similarity search. Its accuracy is similar to Combinatorial Extension (CE and works over 243,000 times faster, searching 34,000 proteins in 0.34 sec with a 3.2-GHz CPU. SARST provides statistically meaningful expectation values to assess the retrieved information. It has been implemented into a web service and a stand-alone Java program that is able to run on many different platforms. Conclusion As a database search method, SARST can rapidly distinguish high from low similarities and efficiently retrieve homologous structures. It demonstrates that the easily accessible linear encoding methodology has the potential to serve as a foundation for efficient protein structural similarity search tools. These search tools are supposed applicable to automated and high-throughput functional annotations or predictions for the ever increasing number of published protein structures in this post-genomic era.

In vitro identification and in silico utilization of interspecies sequence similarities using GeneChip® technology

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Ye Shui Q

2005-05-01

Full Text Available Abstract Background Genomic approaches in large animal models (canine, ovine etc are challenging due to insufficient genomic information for these species and the lack of availability of corresponding microarray platforms. To address this problem, we speculated that conserved interspecies genetic sequences can be experimentally detected by cross-species hybridization. The Affymetrix platform probe redundancy offers flexibility in selecting individual probes with high sequence similarities between related species for gene expression analysis. Results Gene expression profiles of 40 canine samples were generated using the human HG-U133A GeneChip (U133A. Due to interspecies genetic differences, only 14 ± 2% of canine transcripts were detected by U133A probe sets whereas profiling of 40 human samples detected 49 ± 6% of human transcripts. However, when these probe sets were deconstructed into individual probes and examined performance of each probe, we found that 47% of human probes were able to find their targets in canine tissues and generate a detectable hybridization signal. Therefore, we restricted gene expression analysis to these probes and observed the 60% increase in the number of identified canine transcripts. These results were validated by comparison of transcripts identified by our restricted analysis of cross-species hybridization with transcripts identified by hybridization of total lung canine mRNA to new Affymetrix Canine GeneChip®. Conclusion The experimental identification and restriction of gene expression analysis to probes with detectable hybridization signal drastically increases transcript detection of canine-human hybridization suggesting the possibility of broad utilization of cross-hybridizations of related species using GeneChip technology.

Evidence for Genetic Similarity of Vegetative Compatibility Groupings in Sclerotinia homoeocarpa

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Seog Won Chang

2014-12-01

Full Text Available Vegetative compatibility groups (VCGs are determined for many fungi to test for the ability of fungal isolates to undergo heterokaryon formation. In several fungal plant pathogens, isolates belonging to a VCG have been shown to share significantly higher genetic similarity than those of different VCGs. In this study we sought to examine the relationship between VCG and genetic similarity of an important cool season turfgrass pathogen, Sclerotinia homoeocarpa. Twenty-two S. homoeocarpa isolates from the Midwest and Eastern US, which were previously characterized in several studies, were all evaluated for VCG using an improved nit mutant assay. These isolates were also genotyped using 19 microsatellites developed from partial genome sequence of S. homoeocarpa. Additionally, partial sequences of mitochondrial genes cytochrome oxidase II and mitochondrial small subunit (mtSSU rRNA, and the atp6-rns intergenic spacer, were generated for isolates from each nit mutant VCG to determine if mitochondrial haplotypes differed among VCGs. Of the 22 isolates screened, 15 were amenable to the nit mutant VCG assay and were grouped into six VCGs. The 19 microsatellites gave 57 alleles for this set. Unweighted pair group methods with arithmetic mean (UPGMA tree of binary microsatellite data were used to produce a dendrogram of the isolate genotypes based on microsatellite alleles, which showed high genetic similarity of nit mutant VCGs. Analysis of molecular variance of microsatellite data demonstrates that the current nit mutant VCGs explain the microsatellite genotypic variation among isolates better than the previous nit mutant VCGs or the conventionally determined VCGs. Mitochondrial sequences were identical among all isolates, suggesting that this marker type may not be informative for US populations of S. homoeocarpa.

Nuclear and cpDNA sequences combined provide strong inference of higher phylogenetic relationships in the phlox family (Polemoniaceae).

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Johnson, Leigh A; Chan, Lauren M; Weese, Terri L; Busby, Lisa D; McMurry, Samuel

2008-09-01

Members of the phlox family (Polemoniaceae) serve as useful models for studying various evolutionary and biological processes. Despite its biological importance, no family-wide phylogenetic estimate based on multiple DNA regions with complete generic sampling is available. Here, we analyze one nuclear and five chloroplast DNA sequence regions (nuclear ITS, chloroplast matK, trnL intron plus trnL-trnF intergeneric spacer, and the trnS-trnG, trnD-trnT, and psbM-trnD intergenic spacers) using parsimony and Bayesian methods, as well as assessments of congruence and long branch attraction, to explore phylogenetic relationships among 84 ingroup species representing all currently recognized Polemoniaceae genera. Relationships inferred from the ITS and concatenated chloroplast regions are similar overall. A combined analysis provides strong support for the monophyly of Polemoniaceae and subfamilies Acanthogilioideae, Cobaeoideae, and Polemonioideae. Relationships among subfamilies, and thus for the precise root of Polemoniaceae, remain poorly supported. Within the largest subfamily, Polemonioideae, four clades corresponding to tribes Polemonieae, Phlocideae, Gilieae, and Loeselieae receive strong support. The monogeneric Polemonieae appears sister to Phlocideae. Relationships within Polemonieae, Phlocideae, and Gilieae are mostly consistent between analyses and data permutations. Many relationships within Loeselieae remain uncertain. Overall, inferred phylogenetic relationships support a higher-level classification for Polemoniaceae proposed in 2000.

Functional enrichment analyses and construction of functional similarity networks with high confidence function prediction by PFP

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Kihara Daisuke

2010-05-01

Full Text Available Abstract Background A new paradigm of biological investigation takes advantage of technologies that produce large high throughput datasets, including genome sequences, interactions of proteins, and gene expression. The ability of biologists to analyze and interpret such data relies on functional annotation of the included proteins, but even in highly characterized organisms many proteins can lack the functional evidence necessary to infer their biological relevance. Results Here we have applied high confidence function predictions from our automated prediction system, PFP, to three genome sequences, Escherichia coli, Saccharomyces cerevisiae, and Plasmodium falciparum (malaria. The number of annotated genes is increased by PFP to over 90% for all of the genomes. Using the large coverage of the function annotation, we introduced the functional similarity networks which represent the functional space of the proteomes. Four different functional similarity networks are constructed for each proteome, one each by considering similarity in a single Gene Ontology (GO category, i.e. Biological Process, Cellular Component, and Molecular Function, and another one by considering overall similarity with the funSim score. The functional similarity networks are shown to have higher modularity than the protein-protein interaction network. Moreover, the funSim score network is distinct from the single GO-score networks by showing a higher clustering degree exponent value and thus has a higher tendency to be hierarchical. In addition, examining function assignments to the protein-protein interaction network and local regions of genomes has identified numerous cases where subnetworks or local regions have functionally coherent proteins. These results will help interpreting interactions of proteins and gene orders in a genome. Several examples of both analyses are highlighted. Conclusion The analyses demonstrate that applying high confidence predictions from PFP

Sparc: a sparsity-based consensus algorithm for long erroneous sequencing reads

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Chengxi Ye

2016-06-01

Full Text Available Motivation. The third generation sequencing (3GS technology generates long sequences of thousands of bases. However, its current error rates are estimated in the range of 15–40%, significantly higher than those of the prevalent next generation sequencing (NGS technologies (less than 1%. Fundamental bioinformatics tasks such as de novo genome assembly and variant calling require high-quality sequences that need to be extracted from these long but erroneous 3GS sequences. Results. We describe a versatile and efficient linear complexity consensus algorithm Sparc to facilitate de novo genome assembly. Sparc builds a sparse k-mer graph using a collection of sequences from a targeted genomic region. The heaviest path which approximates the most likely genome sequence is searched through a sparsity-induced reweighted graph as the consensus sequence. Sparc supports using NGS and 3GS data together, which leads to significant improvements in both cost efficiency and computational efficiency. Experiments with Sparc show that our algorithm can efficiently provide high-quality consensus sequences using both PacBio and Oxford Nanopore sequencing technologies. With only 30× PacBio data, Sparc can reach a consensus with error rate <0.5%. With the more challenging Oxford Nanopore data, Sparc can also achieve similar error rate when combined with NGS data. Compared with the existing approaches, Sparc calculates the consensus with higher accuracy, and uses approximately 80% less memory and time. Availability. The source code is available for download at https://github.com/yechengxi/Sparc.

A path-based measurement for human miRNA functional similarities using miRNA-disease associations

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Ding, Pingjian; Luo, Jiawei; Xiao, Qiu; Chen, Xiangtao

2016-09-01

Compared with the sequence and expression similarity, miRNA functional similarity is so important for biology researches and many applications such as miRNA clustering, miRNA function prediction, miRNA synergism identification and disease miRNA prioritization. However, the existing methods always utilized the predicted miRNA target which has high false positive and false negative to calculate the miRNA functional similarity. Meanwhile, it is difficult to achieve high reliability of miRNA functional similarity with miRNA-disease associations. Therefore, it is increasingly needed to improve the measurement of miRNA functional similarity. In this study, we develop a novel path-based calculation method of miRNA functional similarity based on miRNA-disease associations, called MFSP. Compared with other methods, our method obtains higher average functional similarity of intra-family and intra-cluster selected groups. Meanwhile, the lower average functional similarity of inter-family and inter-cluster miRNA pair is obtained. In addition, the smaller p-value is achieved, while applying Wilcoxon rank-sum test and Kruskal-Wallis test to different miRNA groups. The relationship between miRNA functional similarity and other information sources is exhibited. Furthermore, the constructed miRNA functional network based on MFSP is a scale-free and small-world network. Moreover, the higher AUC for miRNA-disease prediction indicates the ability of MFSP uncovering miRNA functional similarity.

Pythoscape: A framework for generation of large protein similarity networks

OpenAIRE

Babbitt, Patricia; Barber, AE; Babbitt, PC

2012-01-01

Pythoscape is a framework implemented in Python for processing large protein similarity networks for visualization in other software packages. Protein similarity networks are graphical representations of sequence, structural and other similarities among pr

Multimodal sequence learning.

Science.gov (United States)

Kemény, Ferenc; Meier, Beat

2016-02-01

While sequence learning research models complex phenomena, previous studies have mostly focused on unimodal sequences. The goal of the current experiment is to put implicit sequence learning into a multimodal context: to test whether it can operate across different modalities. We used the Task Sequence Learning paradigm to test whether sequence learning varies across modalities, and whether participants are able to learn multimodal sequences. Our results show that implicit sequence learning is very similar regardless of the source modality. However, the presence of correlated task and response sequences was required for learning to take place. The experiment provides new evidence for implicit sequence learning of abstract conceptual representations. In general, the results suggest that correlated sequences are necessary for implicit sequence learning to occur. Moreover, they show that elements from different modalities can be automatically integrated into one unitary multimodal sequence. Copyright © 2015 Elsevier B.V. All rights reserved.

An approach to large scale identification of non-obvious structural similarities between proteins

Science.gov (United States)

Cherkasov, Artem; Jones, Steven JM

2004-01-01

Background A new sequence independent bioinformatics approach allowing genome-wide search for proteins with similar three dimensional structures has been developed. By utilizing the numerical output of the sequence threading it establishes putative non-obvious structural similarities between proteins. When applied to the testing set of proteins with known three dimensional structures the developed approach was able to recognize structurally similar proteins with high accuracy. Results The method has been developed to identify pathogenic proteins with low sequence identity and high structural similarity to host analogues. Such protein structure relationships would be hypothesized to arise through convergent evolution or through ancient horizontal gene transfer events, now undetectable using current sequence alignment techniques. The pathogen proteins, which could mimic or interfere with host activities, would represent candidate virulence factors. The developed approach utilizes the numerical outputs from the sequence-structure threading. It identifies the potential structural similarity between a pair of proteins by correlating the threading scores of the corresponding two primary sequences against the library of the standard folds. This approach allowed up to 64% sensitivity and 99.9% specificity in distinguishing protein pairs with high structural similarity. Conclusion Preliminary results obtained by comparison of the genomes of Homo sapiens and several strains of Chlamydia trachomatis have demonstrated the potential usefulness of the method in the identification of bacterial proteins with known or potential roles in virulence. PMID:15147578

An approach to large scale identification of non-obvious structural similarities between proteins

Directory of Open Access Journals (Sweden)

Cherkasov Artem

2004-05-01

Full Text Available Abstract Background A new sequence independent bioinformatics approach allowing genome-wide search for proteins with similar three dimensional structures has been developed. By utilizing the numerical output of the sequence threading it establishes putative non-obvious structural similarities between proteins. When applied to the testing set of proteins with known three dimensional structures the developed approach was able to recognize structurally similar proteins with high accuracy. Results The method has been developed to identify pathogenic proteins with low sequence identity and high structural similarity to host analogues. Such protein structure relationships would be hypothesized to arise through convergent evolution or through ancient horizontal gene transfer events, now undetectable using current sequence alignment techniques. The pathogen proteins, which could mimic or interfere with host activities, would represent candidate virulence factors. The developed approach utilizes the numerical outputs from the sequence-structure threading. It identifies the potential structural similarity between a pair of proteins by correlating the threading scores of the corresponding two primary sequences against the library of the standard folds. This approach allowed up to 64% sensitivity and 99.9% specificity in distinguishing protein pairs with high structural similarity. Conclusion Preliminary results obtained by comparison of the genomes of Homo sapiens and several strains of Chlamydia trachomatis have demonstrated the potential usefulness of the method in the identification of bacterial proteins with known or potential roles in virulence.

Estimating the annotation error rate of curated GO database sequence annotations

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Brown Alfred L

2007-05-01

Full Text Available Abstract Background Annotations that describe the function of sequences are enormously important to researchers during laboratory investigations and when making computational inferences. However, there has been little investigation into the data quality of sequence function annotations. Here we have developed a new method of estimating the error rate of curated sequence annotations, and applied this to the Gene Ontology (GO sequence database (GOSeqLite. This method involved artificially adding errors to sequence annotations at known rates, and used regression to model the impact on the precision of annotations based on BLAST matched sequences. Results We estimated the error rate of curated GO sequence annotations in the GOSeqLite database (March 2006 at between 28% and 30%. Annotations made without use of sequence similarity based methods (non-ISS had an estimated error rate of between 13% and 18%. Annotations made with the use of sequence similarity methodology (ISS had an estimated error rate of 49%. Conclusion While the overall error rate is reasonably low, it would be prudent to treat all ISS annotations with caution. Electronic annotators that use ISS annotations as the basis of predictions are likely to have higher false prediction rates, and for this reason designers of these systems should consider avoiding ISS annotations where possible. Electronic annotators that use ISS annotations to make predictions should be viewed sceptically. We recommend that curators thoroughly review ISS annotations before accepting them as valid. Overall, users of curated sequence annotations from the GO database should feel assured that they are using a comparatively high quality source of information.

Defining a similarity threshold for a functional proteinsequence pattern: The signal peptide cleavage site

DEFF Research Database (Denmark)

Nielsen, Henrik; Engelbrecht, Jacob; von Heijne, Gunnar

1996-01-01

When preparing data sets of amino acid or nucleotide sequences it is necessary to exclude redundant or homologous sequences in order to avoid overestimating the predictive performance of an algorithm. For some time methods for doing this have been available in the area of protein structure...... prediction. We have developed a similar procedure based on pair-wise alignments for sequences with functional sites. We show how a correlation coefficient between sequence similarity and functional homology can be used to compare the efficiency of different similarity measures and choose a nonarbitrary...

CLONING AND SEQUENCING OF THE GENE FOR A LACTOCOCCAL ENDOPEPTIDASE, AN ENZYME WITH SEQUENCE SIMILARITY TO MAMMALIAN ENKEPHALINASE

NARCIS (Netherlands)

Mierau, Igor; Tan, Paris S.T.; Haandrikman, Alfred J.; Kok, Jan; Leenhouts, Kees J.; Konings, Wil N.; Venema, Gerard

The gene specifying an endopeptidase of Lactococcus lactis, named pepO, was cloned from a genomic library of L. lactis subsp. cremoris P8-247 in lambdaEMBL3 and was subsequently sequenced. pepO is probably the last gene of an operon encoding the binding-protein-dependent oligopeptide transport

Single nucleus genome sequencing reveals high similarity among nuclei of an endomycorrhizal fungus.

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Kui Lin

2014-01-01

Full Text Available Nuclei of arbuscular endomycorrhizal fungi have been described as highly diverse due to their asexual nature and absence of a single cell stage with only one nucleus. This has raised fundamental questions concerning speciation, selection and transmission of the genetic make-up to next generations. Although this concept has become textbook knowledge, it is only based on studying a few loci, including 45S rDNA. To provide a more comprehensive insight into the genetic makeup of arbuscular endomycorrhizal fungi, we applied de novo genome sequencing of individual nuclei of Rhizophagus irregularis. This revealed a surprisingly low level of polymorphism between nuclei. In contrast, within a nucleus, the 45S rDNA repeat unit turned out to be highly diverged. This finding demystifies a long-lasting hypothesis on the complex genetic makeup of arbuscular endomycorrhizal fungi. Subsequent genome assembly resulted in the first draft reference genome sequence of an arbuscular endomycorrhizal fungus. Its length is 141 Mbps, representing over 27,000 protein-coding gene models. We used the genomic sequence to reinvestigate the phylogenetic relationships of Rhizophagus irregularis with other fungal phyla. This unambiguously demonstrated that Glomeromycota are more closely related to Mucoromycotina than to its postulated sister Dikarya.

Characterization of CG6178 gene product with high sequence similarity to firefly luciferase in Drosophila melanogaster.

Science.gov (United States)

Oba, Yuichi; Ojika, Makoto; Inouye, Satoshi

2004-03-31

This is the first identification of a long-chain fatty acyl-CoA synthetase in Drosophila by enzymatic characterization. The gene product of CG6178 (CG6178) in Drosophila melanogaster genome, which has a high sequence similarity to firefly luciferase, has been expressed and characterized. CG6178 showed long-chain fatty acyl-CoA synthetic activity in the presence of ATP, CoA and Mg(2+), suggesting a fatty acyl adenylate is an intermediate. Recently, it was revealed that firefly luciferase has two catalytic functions, monooxygenase (luciferase) and AMP-mediated CoA ligase (fatty acyl-CoA synthetase). However, unlike firefly luciferase, CG6178 did not show luminescence activity in the presence of firefly luciferin, ATP, CoA and Mg(2+). The enzymatic properties of CG6178 including substrate specificity, pH dependency and optimal temperature were close to those of firefly luciferase and rat fatty acyl-CoA synthetase. Further, phylogenic analyses strongly suggest that the firefly luciferase gene may have evolved from a fatty acyl-CoA synthetase gene as a common ancestral gene.

Purifying selection acts on coding and non-coding sequences of paralogous genes in Arabidopsis thaliana.

Science.gov (United States)

Hoffmann, Robert D; Palmgren, Michael

2016-06-13

Whole-genome duplications in the ancestors of many diverse species provided the genetic material for evolutionary novelty. Several models explain the retention of paralogous genes. However, how these models are reflected in the evolution of coding and non-coding sequences of paralogous genes is unknown. Here, we analyzed the coding and non-coding sequences of paralogous genes in Arabidopsis thaliana and compared these sequences with those of orthologous genes in Arabidopsis lyrata. Paralogs with lower expression than their duplicate had more nonsynonymous substitutions, were more likely to fractionate, and exhibited less similar expression patterns with their orthologs in the other species. Also, lower-expressed genes had greater tissue specificity. Orthologous conserved non-coding sequences in the promoters, introns, and 3' untranslated regions were less abundant at lower-expressed genes compared to their higher-expressed paralogs. A gene ontology (GO) term enrichment analysis showed that paralogs with similar expression levels were enriched in GO terms related to ribosomes, whereas paralogs with different expression levels were enriched in terms associated with stress responses. Loss of conserved non-coding sequences in one gene of a paralogous gene pair correlates with reduced expression levels that are more tissue specific. Together with increased mutation rates in the coding sequences, this suggests that similar forces of purifying selection act on coding and non-coding sequences. We propose that coding and non-coding sequences evolve concurrently following gene duplication.

Self-similar analysis of the spherical implosion process

International Nuclear Information System (INIS)

Ishiguro, Yukio; Katsuragi, Satoru.

1976-07-01

The implosion processes caused by laser-heating ablation has been studied by self-similarity analysis. Attention is paid to the possibility of existence of the self-similar solution which reproduces the implosion process of high compression. Details of the self-similar analysis are reproduced and conclusions are drawn quantitatively on the gas compression by a single shock. The compression process by a sequence of shocks is discussed in self-similarity. The gas motion followed by a homogeneous isentropic compression is represented by a self-similar motion. (auth.)

The RNA world, automatic sequences and oncogenetics

Energy Technology Data Exchange (ETDEWEB)

Tahir Shah, K

1993-04-01

We construct a model of the RNA world in terms of naturally evolving nucleotide sequences assuming only Crick-Watson base pairing and self-cleaving/splicing capability. These sequences have the following properties. (1) They are recognizable by an automation (or automata). That is, to each k-sequence, there exist a k-automation which accepts, recognizes or generates the k-sequence. These are known as automatic sequences. Fibonacci and Morse-Thue sequences are the most natural outcome of pre-biotic chemical conditions. (2) Infinite (resp. large) sequences are self-similar (resp. nearly self-similar) under certain rewrite rules and consequently give rise to fractal (resp.fractal-like) structures. Computationally, such sequences can also be generated by their corresponding deterministic parallel re-write system, known as a DOL system. The self-similar sequences are fixed points of their respective rewrite rules. Some of these automatic sequences have the capability that they can read or ``accept`` other sequences while others can detect errors and trigger error-correcting mechanisms. They can be enlarged and have block and/or palindrome structure. Linear recurring sequences such as Fibonacci sequence are simply Feed-back Shift Registers, a well know model of information processing machines. We show that a mutation of any rewrite rule can cause a combinatorial explosion of error and relates this to oncogenetical behavior. On the other hand, a mutation of sequences that are not rewrite rules, leads to normal evolutionary change. Known experimental results support our hypothesis. (author). Refs.

The RNA world, automatic sequences and oncogenetics

International Nuclear Information System (INIS)

Tahir Shah, K.

1993-04-01

We construct a model of the RNA world in terms of naturally evolving nucleotide sequences assuming only Crick-Watson base pairing and self-cleaving/splicing capability. These sequences have the following properties. 1) They are recognizable by an automation (or automata). That is, to each k-sequence, there exist a k-automation which accepts, recognizes or generates the k-sequence. These are known as automatic sequences. Fibonacci and Morse-Thue sequences are the most natural outcome of pre-biotic chemical conditions. 2) Infinite (resp. large) sequences are self-similar (resp. nearly self-similar) under certain rewrite rules and consequently give rise to fractal (resp.fractal-like) structures. Computationally, such sequences can also be generated by their corresponding deterministic parallel re-write system, known as a DOL system. The self-similar sequences are fixed points of their respective rewrite rules. Some of these automatic sequences have the capability that they can read or 'accept' other sequences while others can detect errors and trigger error-correcting mechanisms. They can be enlarged and have block and/or palindrome structure. Linear recurring sequences such as Fibonacci sequence are simply Feed-back Shift Registers, a well know model of information processing machines. We show that a mutation of any rewrite rule can cause a combinatorial explosion of error and relates this to oncogenetical behavior. On the other hand, a mutation of sequences that are not rewrite rules, leads to normal evolutionary change. Known experimental results support our hypothesis. (author). Refs

Protein-protein interaction network-based detection of functionally similar proteins within species.

Science.gov (United States)

Song, Baoxing; Wang, Fen; Guo, Yang; Sang, Qing; Liu, Min; Li, Dengyun; Fang, Wei; Zhang, Deli

2012-07-01

Although functionally similar proteins across species have been widely studied, functionally similar proteins within species showing low sequence similarity have not been examined in detail. Identification of these proteins is of significant importance for understanding biological functions, evolution of protein families, progression of co-evolution, and convergent evolution and others which cannot be obtained by detection of functionally similar proteins across species. Here, we explored a method of detecting functionally similar proteins within species based on graph theory. After denoting protein-protein interaction networks using graphs, we split the graphs into subgraphs using the 1-hop method. Proteins with functional similarities in a species were detected using a method of modified shortest path to compare these subgraphs and to find the eligible optimal results. Using seven protein-protein interaction networks and this method, some functionally similar proteins with low sequence similarity that cannot detected by sequence alignment were identified. By analyzing the results, we found that, sometimes, it is difficult to separate homologous from convergent evolution. Evaluation of the performance of our method by gene ontology term overlap showed that the precision of our method was excellent. Copyright © 2012 Wiley Periodicals, Inc.

A Unified Theoretical Framework for Cognitive Sequencing.

Science.gov (United States)

Savalia, Tejas; Shukla, Anuj; Bapi, Raju S

2016-01-01

The capacity to sequence information is central to human performance. Sequencing ability forms the foundation stone for higher order cognition related to language and goal-directed planning. Information related to the order of items, their timing, chunking and hierarchical organization are important aspects in sequencing. Past research on sequencing has emphasized two distinct and independent dichotomies: implicit vs. explicit and goal-directed vs. habits. We propose a theoretical framework unifying these two streams. Our proposal relies on brain's ability to implicitly extract statistical regularities from the stream of stimuli and with attentional engagement organizing sequences explicitly and hierarchically. Similarly, sequences that need to be assembled purposively to accomplish a goal require engagement of attentional processes. With repetition, these goal-directed plans become habits with concomitant disengagement of attention. Thus, attention and awareness play a crucial role in the implicit-to-explicit transition as well as in how goal-directed plans become automatic habits. Cortico-subcortical loops basal ganglia-frontal cortex and hippocampus-frontal cortex loops mediate the transition process. We show how the computational principles of model-free and model-based learning paradigms, along with a pivotal role for attention and awareness, offer a unifying framework for these two dichotomies. Based on this framework, we make testable predictions related to the potential influence of response-to-stimulus interval (RSI) on developing awareness in implicit learning tasks.

A Unified Theoretical Framework for Cognitive Sequencing

Directory of Open Access Journals (Sweden)

Tejas Savalia

2016-11-01

Full Text Available The capacity to sequence information is central to human performance. Sequencing ability forms the foundation stone for higher order cognition related to language and goal-directed planning. Information related to the order of items, their timing, chunking and hierarchical organization are important aspects in sequencing. Past research on sequencing has emphasized two distinct and independent dichotomies: implicit versus explicit and goal-directed versus habits. We propose a theoretical framework unifying these two streams. Our proposal relies on brain's ability to implicitly extract statistical regularities from the stream of stimuli and with attentional engagement organizing sequences explicitly and hierarchically. Similarly, sequences that need to be assembled purposively to accomplish a goal require engagement of attentional processes. With repetition, these goal-directed plans become habits with concomitant disengagement of attention. Thus attention and awareness play a crucial role in the implicit-to-explicit transition as well as in how goal-directed plans become automatic habits. Cortico-subcortical loops ─ basal ganglia-frontal cortex and hippocampus-frontal cortex loops ─ mediate the transition process. We show how the computational principles of model-free and model-based learning paradigms, along with a pivotal role for attention and awareness, offer a unifying framework for these two dichotomies. Based on this framework, we make testable predictions related to the potential influence of response-to-stimulus interval (RSI on developing awareness in implicit learning tasks.

Characterization of a highly toxic strain of Bacillus thuringiensis serovar kurstaki very similar to the HD-73 strain.

Science.gov (United States)

Reinoso-Pozo, Yaritza; Del Rincón-Castro, Ma Cristina; Ibarra, Jorge E

2016-09-01

The LBIT-1200 strain of Bacillus thuringiensis was recently isolated from soil, and showed a 6.4 and 9.5 increase in toxicity, against Manduca sexta and Trichoplusia ni, respectively, compared to HD-73. However, LBIT-1200 was still highly similar to HD-73, including the production of bipyramidal crystals containing only one protein of ∼130 000 kDa, its flagellin gene sequence related to the kurstaki serotype, plasmid and RepPCR patterns similar to HD-73, no production of β-exotoxin and no presence of VIP genes. Sequencing of its cry gene showed the presence of a cry1Ac-type gene with four amino acid differences, including two amino acid replacements in domain III, compared to Cry1Ac1, which may explain its higher toxicity. In conclusion, the LBIT-1200 strain is a variant of the HD-73 strain but shows a much higher toxicity, which makes this new strain an important candidate to be developed as a bioinsecticide, once it passes other tests, throughout its biotechnological development. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Structural and Sequence Similarities of Hydra Xeroderma Pigmentosum A Protein to Human Homolog Suggest Early Evolution and Conservation

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Apurva Barve

2013-01-01

Full Text Available Xeroderma pigmentosum group A (XPA is a protein that binds to damaged DNA, verifies presence of a lesion, and recruits other proteins of the nucleotide excision repair (NER pathway to the site. Though its homologs from yeast, Drosophila, humans, and so forth are well studied, XPA has not so far been reported from protozoa and lower animal phyla. Hydra is a fresh-water cnidarian with a remarkable capacity for regeneration and apparent lack of organismal ageing. Cnidarians are among the first metazoa with a defined body axis, tissue grade organisation, and nervous system. We report here for the first time presence of XPA gene in hydra. Putative protein sequence of hydra XPA contains nuclear localization signal and bears the zinc-finger motif. It contains two conserved Pfam domains and various characterized features of XPA proteins like regions for binding to excision repair cross-complementing protein-1 (ERCC1 and replication protein A 70 kDa subunit (RPA70 proteins. Hydra XPA shows a high degree of similarity with vertebrate homologs and clusters with deuterostomes in phylogenetic analysis. Homology modelling corroborates the very close similarity between hydra and human XPA. The protein thus most likely functions in hydra in the same manner as in other animals, indicating that it arose early in evolution and has been conserved across animal phyla.

Complete genome sequence of an isolate of Potato virus X (PVX) infecting Cape gooseberry (Physalis peruviana) in Colombia.

Science.gov (United States)

Gutiérrez, Pablo A; Alzate, Juan F; Montoya, Mauricio Marín

2015-06-01

Transcriptome analysis of a Cape gooseberry (Physalis peruviana) plant with leaf symptoms of a mild yellow mosaic typical of a viral disease revealed an infection with Potato virus X (PVX). The genome sequence of the PVX-Physalis isolate comprises 6435 nt and exhibits higher sequence similarity to members of the Eurasian group of PVX (~95 %) than to the American group (~77 %). Genome organization is similar to other PVX isolates with five open reading frames coding for proteins RdRp, TGBp1, TGBp2, TGBp3, and CP. 5' and 3' untranslated regions revealed all regulatory motifs typically found in PVX isolates. The PVX-Physalis genome is the only complete sequence available for a Potexvirus in Colombia and is a new addition to the restricted number of available sequences of PVX isolates infecting plant species different to potato.

HBLAST: Parallelised sequence similarity--A Hadoop MapReducable basic local alignment search tool.

Science.gov (United States)

O'Driscoll, Aisling; Belogrudov, Vladislav; Carroll, John; Kropp, Kai; Walsh, Paul; Ghazal, Peter; Sleator, Roy D

2015-04-01

The recent exponential growth of genomic databases has resulted in the common task of sequence alignment becoming one of the major bottlenecks in the field of computational biology. It is typical for these large datasets and complex computations to require cost prohibitive High Performance Computing (HPC) to function. As such, parallelised solutions have been proposed but many exhibit scalability limitations and are incapable of effectively processing "Big Data" - the name attributed to datasets that are extremely large, complex and require rapid processing. The Hadoop framework, comprised of distributed storage and a parallelised programming framework known as MapReduce, is specifically designed to work with such datasets but it is not trivial to efficiently redesign and implement bioinformatics algorithms according to this paradigm. The parallelisation strategy of "divide and conquer" for alignment algorithms can be applied to both data sets and input query sequences. However, scalability is still an issue due to memory constraints or large databases, with very large database segmentation leading to additional performance decline. Herein, we present Hadoop Blast (HBlast), a parallelised BLAST algorithm that proposes a flexible method to partition both databases and input query sequences using "virtual partitioning". HBlast presents improved scalability over existing solutions and well balanced computational work load while keeping database segmentation and recompilation to a minimum. Enhanced BLAST search performance on cheap memory constrained hardware has significant implications for in field clinical diagnostic testing; enabling faster and more accurate identification of pathogenic DNA in human blood or tissue samples. Copyright © 2015 Elsevier Inc. All rights reserved.

Universal sequence map (USM of arbitrary discrete sequences

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Almeida Jonas S

2002-02-01

Full Text Available Abstract Background For over a decade the idea of representing biological sequences in a continuous coordinate space has maintained its appeal but not been fully realized. The basic idea is that any sequence of symbols may define trajectories in the continuous space conserving all its statistical properties. Ideally, such a representation would allow scale independent sequence analysis – without the context of fixed memory length. A simple example would consist on being able to infer the homology between two sequences solely by comparing the coordinates of any two homologous units. Results We have successfully identified such an iterative function for bijective mappingψ of discrete sequences into objects of continuous state space that enable scale-independent sequence analysis. The technique, named Universal Sequence Mapping (USM, is applicable to sequences with an arbitrary length and arbitrary number of unique units and generates a representation where map distance estimates sequence similarity. The novel USM procedure is based on earlier work by these and other authors on the properties of Chaos Game Representation (CGR. The latter enables the representation of 4 unit type sequences (like DNA as an order free Markov Chain transition table. The properties of USM are illustrated with test data and can be verified for other data by using the accompanying web-based tool:http://bioinformatics.musc.edu/~jonas/usm/. Conclusions USM is shown to enable a statistical mechanics approach to sequence analysis. The scale independent representation frees sequence analysis from the need to assume a memory length in the investigation of syntactic rules.

Cloning, sequencing, and sequence analysis of two novel plasmids from the thermophilic anaerobic bacterium Anaerocellum thermophilum

DEFF Research Database (Denmark)

Clausen, Anders; Mikkelsen, Marie Just; Schrøder, I.

2004-01-01

The nucleotide sequence of two novel plasmids isolated from the extreme thermophilic anaerobic bacterium Anaerocellum thermophilum DSM6725 (A. thermophilum), growing optimally at 70degreesC, has been determined. pBAS2 was found to be a 3653 bp plasmid with a GC content of 43%, and the sequence re...... with highest similarity to DNA repair protein from Campylobacter jejuni (25% aa). Orf34 showed similarity to sigma factors with highest similarity (28% aa) to the sporulation specific Sigma factor, Sigma 28(K) from Bacillus thuringiensis....

Microbiota epitope similarity either dampens or enhances the immunogenicity of disease-associated antigenic epitopes.

Directory of Open Access Journals (Sweden)

Sebastian Carrasco Pro

Full Text Available The microbiome influences adaptive immunity and molecular mimicry influences T cell reactivity. Here, we evaluated whether the sequence similarity of various antigens to the microbiota dampens or increases immunogenicity of T cell epitopes. Sets of epitopes and control sequences derived from 38 antigenic categories (infectious pathogens, allergens, autoantigens were retrieved from the Immune Epitope Database (IEDB. Their similarity to microbiome sequences was calculated using the BLOSUM62 matrix. We found that sequence similarity was associated with either dampened (tolerogenic; e.g. most allergens or increased (inflammatory; e.g. Dengue and West Nile viruses likelihood of a peptide being immunogenic as a function of epitope source category. Ten-fold cross-validation and validation using sets of manually curated epitopes and non-epitopes derived from allergens were used to confirm these initial observations. Furthermore, the genus from which the microbiome homologous sequences were derived influenced whether a tolerogenic versus inflammatory modulatory effect was observed, with Fusobacterium most associated with inflammatory influences and Bacteroides most associated with tolerogenic influences. We validated these effects using PBMCs stimulated with various sets of microbiome peptides. "Tolerogenic" microbiome peptides elicited IL-10 production, "inflammatory" peptides elicited mixed IL-10/IFNγ production, while microbiome epitopes homologous to self were completely unreactive for both cytokines. We also tested the sequence similarity of cockroach epitopes to specific microbiome sequences derived from households of cockroach allergic individuals and non-allergic controls. Microbiomes from cockroach allergic households were less likely to contain sequences homologous to previously defined cockroach allergens. These results are compatible with the hypothesis that microbiome sequences may contribute to the tolerization of T cells for allergen

A putative carbohydrate-binding domain of the lactose-binding Cytisus sessilifolius anti-H(O) lectin has a similar amino acid sequence to that of the L-fucose-binding Ulex europaeus anti-H(O) lectin.

Science.gov (United States)

Konami, Y; Yamamoto, K; Osawa, T; Irimura, T

1995-04-01

The complete amino acid sequence of a lactose-binding Cytisus sessilifolius anti-H(O) lectin II (CSA-II) was determined using a protein sequencer. After digestion of CSA-II with endoproteinase Lys-C or Asp-N, the resulting peptides were purified by reversed-phase high performance liquid chromatography (HPLC) and then subjected to sequence analysis. Comparison of the complete amino acid sequence of CSA-II with the sequences of other leguminous seed lectins revealed regions of extensive homology. The amino acid sequence of a putative carbohydrate-binding domain of CSA-II was found to be similar to those of several anti-H(O) leguminous lectins, especially to that of the L-fucose-binding Ulex europaeus lectin I (UEA-I).

Application of Quaternion in improving the quality of global sequence alignment scores for an ambiguous sequence target in Streptococcus pneumoniae DNA

Science.gov (United States)

Lestari, D.; Bustamam, A.; Novianti, T.; Ardaneswari, G.

2017-07-01

DNA sequence can be defined as a succession of letters, representing the order of nucleotides within DNA, using a permutation of four DNA base codes including adenine (A), guanine (G), cytosine (C), and thymine (T). The precise code of the sequences is determined using DNA sequencing methods and technologies, which have been developed since the 1970s and currently become highly developed, advanced and highly throughput sequencing technologies. So far, DNA sequencing has greatly accelerated biological and medical research and discovery. However, in some cases DNA sequencing could produce any ambiguous and not clear enough sequencing results that make them quite difficult to be determined whether these codes are A, T, G, or C. To solve these problems, in this study we can introduce other representation of DNA codes namely Quaternion Q = (PA, PT, PG, PC), where PA, PT, PG, PC are the probability of A, T, G, C bases that could appear in Q and PA + PT + PG + PC = 1. Furthermore, using Quaternion representations we are able to construct the improved scoring matrix for global sequence alignment processes, by applying a dot product method. Moreover, this scoring matrix produces better and higher quality of the match and mismatch score between two DNA base codes. In implementation, we applied the Needleman-Wunsch global sequence alignment algorithm using Octave, to analyze our target sequence which contains some ambiguous sequence data. The subject sequences are the DNA sequences of Streptococcus pneumoniae families obtained from the Genebank, meanwhile the target DNA sequence are received from our collaborator database. As the results we found the Quaternion representations improve the quality of the sequence alignment score and we can conclude that DNA sequence target has maximum similarity with Streptococcus pneumoniae.

Whole-genome sequencing of asian lung cancers: second-hand smoke unlikely to be responsible for higher incidence of lung cancer among Asian never-smokers.

Science.gov (United States)

Krishnan, Vidhya G; Ebert, Philip J; Ting, Jason C; Lim, Elaine; Wong, Swee-Seong; Teo, Audrey S M; Yue, Yong G; Chua, Hui-Hoon; Ma, Xiwen; Loh, Gary S L; Lin, Yuhao; Tan, Joanna H J; Yu, Kun; Zhang, Shenli; Reinhard, Christoph; Tan, Daniel S W; Peters, Brock A; Lincoln, Stephen E; Ballinger, Dennis G; Laramie, Jason M; Nilsen, Geoffrey B; Barber, Thomas D; Tan, Patrick; Hillmer, Axel M; Ng, Pauline C

2014-11-01

Asian nonsmoking populations have a higher incidence of lung cancer compared with their European counterparts. There is a long-standing hypothesis that the increase of lung cancer in Asian never-smokers is due to environmental factors such as second-hand smoke. We analyzed whole-genome sequencing of 30 Asian lung cancers. Unsupervised clustering of mutational signatures separated the patients into two categories of either all the never-smokers or all the smokers or ex-smokers. In addition, nearly one third of the ex-smokers and smokers classified with the never-smoker-like cluster. The somatic variant profiles of Asian lung cancers were similar to that of European origin with G.C>T.A being predominant in smokers. We found EGFR and TP53 to be the most frequently mutated genes with mutations in 50% and 27% of individuals, respectively. Among the 16 never-smokers, 69% had an EGFR mutation compared with 29% of 14 smokers/ex-smokers. Asian never-smokers had lung cancer signatures distinct from the smoker signature and their mutation profiles were similar to European never-smokers. The profiles of Asian and European smokers are also similar. Taken together, these results suggested that the same mutational mechanisms underlie the etiology for both ethnic groups. Thus, the high incidence of lung cancer in Asian never-smokers seems unlikely to be due to second-hand smoke or other carcinogens that cause oxidative DNA damage, implying that routine EGFR testing is warranted in the Asian population regardless of smoking status. ©2014 American Association for Cancer Research.

Sequence similarity between the erythrocyte binding domain 1 of the Plasmodium vivax Duffy binding protein and the V3 loop of HIV-1 strain MN reveals binding residues for the Duffy Antigen Receptor for Chemokines

OpenAIRE

Bolton, Michael J; Garry, Robert F

2011-01-01

Abstract Background The surface glycoprotein (SU, gp120) of the human immunodeficiency virus (HIV) must bind to a chemokine receptor, CCR5 or CXCR4, to invade CD4+ cells. Plasmodium vivax uses the Duffy Binding Protein (DBP) to bind the Duffy Antigen Receptor for Chemokines (DARC) and invade reticulocytes. Results Variable loop 3 (V3) of HIV-1 SU and domain 1 of the Plasmodium vivax DBP share a sequence similarity. The site of amino acid sequence similarity was necessary, but not sufficient, ...

Self-similar pattern formation and continuous mechanics of self-similar systems

Directory of Open Access Journals (Sweden)

A. V. Dyskin

2007-01-01

Full Text Available In many cases, the critical state of systems that reached the threshold is characterised by self-similar pattern formation. We produce an example of pattern formation of this kind – formation of self-similar distribution of interacting fractures. Their formation starts with the crack growth due to the action of stress fluctuations. It is shown that even when the fluctuations have zero average the cracks generated by them could grow far beyond the scale of stress fluctuations. Further development of the fracture system is controlled by crack interaction leading to the emergence of self-similar crack distributions. As a result, the medium with fractures becomes discontinuous at any scale. We develop a continuum fractal mechanics to model its physical behaviour. We introduce a continuous sequence of continua of increasing scales covering this range of scales. The continuum of each scale is specified by the representative averaging volume elements of the corresponding size. These elements determine the resolution of the continuum. Each continuum hides the cracks of scales smaller than the volume element size while larger fractures are modelled explicitly. Using the developed formalism we investigate the stability of self-similar crack distributions with respect to crack growth and show that while the self-similar distribution of isotropically oriented cracks is stable, the distribution of parallel cracks is not. For the isotropically oriented cracks scaling of permeability is determined. For permeable materials (rocks with self-similar crack distributions permeability scales as cube of crack radius. This property could be used for detecting this specific mechanism of formation of self-similar crack distributions.

Comparative genomics beyond sequence-based alignments

DEFF Research Database (Denmark)

Þórarinsson, Elfar; Yao, Zizhen; Wiklund, Eric D.

2008-01-01

Recent computational scans for non-coding RNAs (ncRNAs) in multiple organisms have relied on existing multiple sequence alignments. However, as sequence similarity drops, a key signal of RNA structure--frequent compensating base changes--is increasingly likely to cause sequence-based alignment me...

When Does Between-Sequence Phonological Similarity Promote Irrelevant Sound Disruption?

Science.gov (United States)

Marsh, John E.; Vachon, Francois; Jones, Dylan M.

2008-01-01

Typically, the phonological similarity between to-be-recalled items and TBI auditory stimuli has no impact if recall in serial order is required. However, in the present study, the authors have shown that the free recall, but not serial recall, of lists of phonologically related to-be-remembered items was disrupted by an irrelevant sound stream…

Subgrouping Automata: automatic sequence subgrouping using phylogenetic tree-based optimum subgrouping algorithm.

Science.gov (United States)

Seo, Joo-Hyun; Park, Jihyang; Kim, Eun-Mi; Kim, Juhan; Joo, Keehyoung; Lee, Jooyoung; Kim, Byung-Gee

2014-02-01

Sequence subgrouping for a given sequence set can enable various informative tasks such as the functional discrimination of sequence subsets and the functional inference of unknown sequences. Because an identity threshold for sequence subgrouping may vary according to the given sequence set, it is highly desirable to construct a robust subgrouping algorithm which automatically identifies an optimal identity threshold and generates subgroups for a given sequence set. To meet this end, an automatic sequence subgrouping method, named 'Subgrouping Automata' was constructed. Firstly, tree analysis module analyzes the structure of tree and calculates the all possible subgroups in each node. Sequence similarity analysis module calculates average sequence similarity for all subgroups in each node. Representative sequence generation module finds a representative sequence using profile analysis and self-scoring for each subgroup. For all nodes, average sequence similarities are calculated and 'Subgrouping Automata' searches a node showing statistically maximum sequence similarity increase using Student's t-value. A node showing the maximum t-value, which gives the most significant differences in average sequence similarity between two adjacent nodes, is determined as an optimum subgrouping node in the phylogenetic tree. Further analysis showed that the optimum subgrouping node from SA prevents under-subgrouping and over-subgrouping. Copyright © 2013. Published by Elsevier Ltd.

Polynomial sequences generated by infinite Hessenberg matrices

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Verde-Star Luis

2017-01-01

Full Text Available We show that an infinite lower Hessenberg matrix generates polynomial sequences that correspond to the rows of infinite lower triangular invertible matrices. Orthogonal polynomial sequences are obtained when the Hessenberg matrix is tridiagonal. We study properties of the polynomial sequences and their corresponding matrices which are related to recurrence relations, companion matrices, matrix similarity, construction algorithms, and generating functions. When the Hessenberg matrix is also Toeplitz the polynomial sequences turn out to be of interpolatory type and we obtain additional results. For example, we show that every nonderogative finite square matrix is similar to a unique Toeplitz-Hessenberg matrix.

Two genes with similarity to bacterial response regulators are rapidly and specifically induced by cytokinin in Arabidopsis

Science.gov (United States)

Brandstatter, I.; Kieber, J. J.; Evans, M. L. (Principal Investigator)

1998-01-01

Cytokinins are central regulators of plant growth and development, but little is known about their mode of action. By using differential display, we identified a gene, IBC6 (for induced by cytokinin), from etiolated Arabidopsis seedlings, that is induced rapidly by cytokinin. The steady state level of IBC6 mRNA was elevated within 10 min by the exogenous application of cytokinin, and this induction did not require de novo protein synthesis. IBC6 was not induced by other plant hormones or by light. A second Arabidopsis gene with a sequence highly similar to IBC6 was identified. This IBC7 gene also was induced by cytokinin, although with somewhat slower kinetics and to a lesser extent. The pattern of expression of the two genes was similar, with higher expression in leaves, rachises, and flowers and lower transcript levels in roots and siliques. Sequence analysis revealed that IBC6 and IBC7 are similar to the receiver domain of bacterial two-component response regulators. This homology, coupled with previously published work on the CKI1 histidine kinase homolog, suggests that these proteins may play a role in early cytokinin signaling.

muBLASTP: database-indexed protein sequence search on multicore CPUs.

Science.gov (United States)

Zhang, Jing; Misra, Sanchit; Wang, Hao; Feng, Wu-Chun

2016-11-04

The Basic Local Alignment Search Tool (BLAST) is a fundamental program in the life sciences that searches databases for sequences that are most similar to a query sequence. Currently, the BLAST algorithm utilizes a query-indexed approach. Although many approaches suggest that sequence search with a database index can achieve much higher throughput (e.g., BLAT, SSAHA, and CAFE), they cannot deliver the same level of sensitivity as the query-indexed BLAST, i.e., NCBI BLAST, or they can only support nucleotide sequence search, e.g., MegaBLAST. Due to different challenges and characteristics between query indexing and database indexing, the existing techniques for query-indexed search cannot be used into database indexed search. muBLASTP, a novel database-indexed BLAST for protein sequence search, delivers identical hits returned to NCBI BLAST. On Intel Haswell multicore CPUs, for a single query, the single-threaded muBLASTP achieves up to a 4.41-fold speedup for alignment stages, and up to a 1.75-fold end-to-end speedup over single-threaded NCBI BLAST. For a batch of queries, the multithreaded muBLASTP achieves up to a 5.7-fold speedups for alignment stages, and up to a 4.56-fold end-to-end speedup over multithreaded NCBI BLAST. With a newly designed index structure for protein database and associated optimizations in BLASTP algorithm, we re-factored BLASTP algorithm for modern multicore processors that achieves much higher throughput with acceptable memory footprint for the database index.

Location of the redox-active thiols of ribonucleotide reductase: sequences similarity between the Escherichia coli and Lactobacillus leichmannii enzymes

International Nuclear Information System (INIS)

Lin, A.N.I.; Ashley, G.W.; Stubbe, J.

1987-01-01

The redox-active thiols of Escherichia coli ribonucleoside diphosphate reductase and of Lactobacillus leichmannii ribonucleoside triphosphate reductase have been located by a procedure involving (1) prereduction of enzyme with dithiothreitol, (2) specific oxidation of the redox-active thiols by treatment with substrate in the absence of exogenous reductant, (3) alkylation of other thiols with iodoacetamide, and (4) reduction of the disulfides with dithiothreitol and alkylation with [1- 14 C]iodoacetamide. The dithiothreitol-reduce E. coli B1 subunit is able to convert 3 equiv of CDP to dCDP and is labeled with 5.4 equiv of 14 C. Sequencing of tryptic peptides shows that 2.8 equiv of 14 C is on cysteines-752 and -757 at the C-terminus of B1, while 1.0-1.5 equiv of 14 C is on cysteines-222 and -227. It thus appears that two sets of redox-active dithiols are involved in substrate reduction. The L. leichmannii reductase is able to convert 1.1 equiv of CTP to dCTP and is labeled with 2.1 equiv of 14 C. Sequencing of tryptic peptides shows that 1.4 equiv of 14 C is located on the two cysteines of C-E-G-G-A-C-P-I-K. This peptide shows remarkable and unexpected similarity to the thiol-containing region of the C-terminal peptide of E. coli B1, C-E-S-G-A-C-K-I

Formatt: Correcting protein multiple structural alignments by incorporating sequence alignment

Directory of Open Access Journals (Sweden)

Daniels Noah M

2012-10-01

Full Text Available Abstract Background The quality of multiple protein structure alignments are usually computed and assessed based on geometric functions of the coordinates of the backbone atoms from the protein chains. These purely geometric methods do not utilize directly protein sequence similarity, and in fact, determining the proper way to incorporate sequence similarity measures into the construction and assessment of protein multiple structure alignments has proved surprisingly difficult. Results We present Formatt, a multiple structure alignment based on the Matt purely geometric multiple structure alignment program, that also takes into account sequence similarity when constructing alignments. We show that Formatt outperforms Matt and other popular structure alignment programs on the popular HOMSTRAD benchmark. For the SABMark twilight zone benchmark set that captures more remote homology, Formatt and Matt outperform other programs; depending on choice of embedded sequence aligner, Formatt produces either better sequence and structural alignments with a smaller core size than Matt, or similarly sized alignments with better sequence similarity, for a small cost in average RMSD. Conclusions Considering sequence information as well as purely geometric information seems to improve quality of multiple structure alignments, though defining what constitutes the best alignment when sequence and structural measures would suggest different alignments remains a difficult open question.

cDNA sequencing improves the detection of P53 missense mutations in colorectal cancer

International Nuclear Information System (INIS)

Szybka, Malgorzata; Kordek, Radzislaw; Zakrzewska, Magdalena; Rieske, Piotr; Pasz-Walczak, Grazyna; Kulczycka-Wojdala, Dominika; Zawlik, Izabela; Stawski, Robert; Jesionek-Kupnicka, Dorota; Liberski, Pawel P

2009-01-01

Recently published data showed discrepancies beteween P53 cDNA and DNA sequencing in glioblastomas. We hypothesised that similar discrepancies may be observed in other human cancers. To this end, we analyzed 23 colorectal cancers for P53 mutations and gene expression using both DNA and cDNA sequencing, real-time PCR and immunohistochemistry. We found P53 gene mutations in 16 cases (15 missense and 1 nonsense). Two of the 15 cases with missense mutations showed alterations based only on cDNA, and not DNA sequencing. Moreover, in 6 of the 15 cases with a cDNA mutation those mutations were difficult to detect in the DNA sequencing, so the results of DNA analysis alone could be misinterpreted if the cDNA sequencing results had not also been available. In all those 15 cases, we observed a higher ratio of the mutated to the wild type template by cDNA analysis, but not by the DNA analysis. Interestingly, a similar overexpression of P53 mRNA was present in samples with and without P53 mutations. In terms of colorectal cancer, those discrepancies might be explained under three conditions: 1, overexpression of mutated P53 mRNA in cancer cells as compared with normal cells; 2, a higher content of cells without P53 mutation (normal cells and cells showing K-RAS and/or APC but not P53 mutation) in samples presenting P53 mutation; 3, heterozygous or hemizygous mutations of P53 gene. Additionally, for heterozygous mutations unknown mechanism(s) causing selective overproduction of mutated allele should also be considered. Our data offer new clues for studying discrepancy in P53 cDNA and DNA sequencing analysis

Molecular phylogeny and species separation of five morphologically similar Holosticha-complex ciliates (Protozoa, Ciliophora) using ARDRA riboprinting and multigene sequence data

Science.gov (United States)

Gao, Feng; Yi, Zhenzhen; Gong, Jun; Al-Rasheid Khaled, A. S.; Song, Weibo

2010-05-01

To separate and redefine the ambiguous Holosticha-complex, a confusing group of hypotrichous ciliates, six strains belonging to five morphospecies of three genera, Holosticha heterofoissneri, Anteholosticha sp. pop1, Anteholosticha sp. pop2, A. manca, A. gracilis and Nothoholosticha fasciola, were analyzed using 12 restriction enzymes on the basis of amplified ribosomal DNA restriction analysis. Nine of the 12 enzymes could digest the DNA products, four ( Hinf I, Hind III, Msp I, Taq I) yielded species-specific restriction patterns, and Hind III and Taq I produced different patterns for two Anteholosticha sp. populations. Distinctly different restriction digestion haplotypes and similarity indices can be used to separate the species. The secondary structures of the five species were predicted based on the ITS2 transcripts and there were several minor differences among species, while two Anteholosticha sp. populations were identical. In addition, phylogenies based on the SSrRNA gene sequences were reconstructed using multiple algorithms, which grouped them generally into four clades, and exhibited that the genus Anteholosticha should be a convergent assemblage. The fact that Holosticha species clustered with the oligotrichs and choreotrichs, though with very low support values, indicated that the topology may be very divergent and unreliable when the number of sequence data used in the analyses is too low.

Bumblebees (Bombus terrestris) and honeybees (Apis mellifera) prefer similar colours of higher spectral purity over trained colours.

Science.gov (United States)

Rohde, Katja; Papiorek, Sarah; Lunau, Klaus

2013-03-01

Differences in the concentration of pigments as well as their composition and spatial arrangement cause intraspecific variation in the spectral signature of flowers. Known colour preferences and requirements for flower-constant foraging bees predict different responses to colour variability. In experimental settings, we simulated small variations of unicoloured petals and variations in the spatial arrangement of colours within tricoloured petals using artificial flowers and studied their impact on the colour choices of bumblebees and honeybees. Workers were trained to artificial flowers of a given colour and then given the simultaneous choice between three test colours: either the training colour, one colour of lower and one of higher spectral purity, or the training colour, one colour of lower and one of higher dominant wavelength; in all cases the perceptual contrast between the training colour and the additional test colours was similarly small. Bees preferred artificial test flowers which resembled the training colour with the exception that they preferred test colours with higher spectral purity over trained colours. Testing the behaviour of bees at artificial flowers displaying a centripetal or centrifugal arrangement of three equally sized colours with small differences in spectral purity, bees did not prefer any type of artificial flowers, but preferentially choose the most spectrally pure area for the first antenna contact at both types of artificial flowers. Our results indicate that innate preferences for flower colours of high spectral purity in pollinators might exert selective pressure on the evolution of flower colours.

Roles of repetitive sequences

Energy Technology Data Exchange (ETDEWEB)

Bell, G.I.

1991-12-31

The DNA of higher eukaryotes contains many repetitive sequences. The study of repetitive sequences is important, not only because many have important biological function, but also because they provide information on genome organization, evolution and dynamics. In this paper, I will first discuss some generic effects that repetitive sequences will have upon genome dynamics and evolution. In particular, it will be shown that repetitive sequences foster recombination among, and turnover of, the elements of a genome. I will then consider some examples of repetitive sequences, notably minisatellite sequences and telomere sequences as examples of tandem repeats, without and with respectively known function, and Alu sequences as an example of interspersed repeats. Some other examples will also be considered in less detail.

Genomic insight into the common carp (Cyprinus carpio genome by sequencing analysis of BAC-end sequences

Directory of Open Access Journals (Sweden)

Wang Jintu

2011-04-01

Full Text Available Abstract Background Common carp is one of the most important aquaculture teleost fish in the world. Common carp and other closely related Cyprinidae species provide over 30% aquaculture production in the world. However, common carp genomic resources are still relatively underdeveloped. BAC end sequences (BES are important resources for genome research on BAC-anchored genetic marker development, linkage map and physical map integration, and whole genome sequence assembling and scaffolding. Result To develop such valuable resources in common carp (Cyprinus carpio, a total of 40,224 BAC clones were sequenced on both ends, generating 65,720 clean BES with an average read length of 647 bp after sequence processing, representing 42,522,168 bp or 2.5% of common carp genome. The first survey of common carp genome was conducted with various bioinformatics tools. The common carp genome contains over 17.3% of repetitive elements with GC content of 36.8% and 518 transposon ORFs. To identify and develop BAC-anchored microsatellite markers, a total of 13,581 microsatellites were detected from 10,355 BES. The coding region of 7,127 genes were recognized from 9,443 BES on 7,453 BACs, with 1,990 BACs have genes on both ends. To evaluate the similarity to the genome of closely related zebrafish, BES of common carp were aligned against zebrafish genome. A total of 39,335 BES of common carp have conserved homologs on zebrafish genome which demonstrated the high similarity between zebrafish and common carp genomes, indicating the feasibility of comparative mapping between zebrafish and common carp once we have physical map of common carp. Conclusion BAC end sequences are great resources for the first genome wide survey of common carp. The repetitive DNA was estimated to be approximate 28% of common carp genome, indicating the higher complexity of the genome. Comparative analysis had mapped around 40,000 BES to zebrafish genome and established over 3

Genomic insight into the common carp (Cyprinus carpio) genome by sequencing analysis of BAC-end sequences

Science.gov (United States)

2011-01-01

Background Common carp is one of the most important aquaculture teleost fish in the world. Common carp and other closely related Cyprinidae species provide over 30% aquaculture production in the world. However, common carp genomic resources are still relatively underdeveloped. BAC end sequences (BES) are important resources for genome research on BAC-anchored genetic marker development, linkage map and physical map integration, and whole genome sequence assembling and scaffolding. Result To develop such valuable resources in common carp (Cyprinus carpio), a total of 40,224 BAC clones were sequenced on both ends, generating 65,720 clean BES with an average read length of 647 bp after sequence processing, representing 42,522,168 bp or 2.5% of common carp genome. The first survey of common carp genome was conducted with various bioinformatics tools. The common carp genome contains over 17.3% of repetitive elements with GC content of 36.8% and 518 transposon ORFs. To identify and develop BAC-anchored microsatellite markers, a total of 13,581 microsatellites were detected from 10,355 BES. The coding region of 7,127 genes were recognized from 9,443 BES on 7,453 BACs, with 1,990 BACs have genes on both ends. To evaluate the similarity to the genome of closely related zebrafish, BES of common carp were aligned against zebrafish genome. A total of 39,335 BES of common carp have conserved homologs on zebrafish genome which demonstrated the high similarity between zebrafish and common carp genomes, indicating the feasibility of comparative mapping between zebrafish and common carp once we have physical map of common carp. Conclusion BAC end sequences are great resources for the first genome wide survey of common carp. The repetitive DNA was estimated to be approximate 28% of common carp genome, indicating the higher complexity of the genome. Comparative analysis had mapped around 40,000 BES to zebrafish genome and established over 3,100 microsyntenies, covering over 50% of

Similarity of Symbol Frequency Distributions with Heavy Tails

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Martin Gerlach

2016-04-01

Full Text Available Quantifying the similarity between symbolic sequences is a traditional problem in information theory which requires comparing the frequencies of symbols in different sequences. In numerous modern applications, ranging from DNA over music to texts, the distribution of symbol frequencies is characterized by heavy-tailed distributions (e.g., Zipf’s law. The large number of low-frequency symbols in these distributions poses major difficulties to the estimation of the similarity between sequences; e.g., they hinder an accurate finite-size estimation of entropies. Here, we show analytically how the systematic (bias and statistical (fluctuations errors in these estimations depend on the sample size N and on the exponent γ of the heavy-tailed distribution. Our results are valid for the Shannon entropy (α=1, its corresponding similarity measures (e.g., the Jensen-Shanon divergence, and also for measures based on the generalized entropy of order α. For small α’s, including α=1, the errors decay slower than the 1/N decay observed in short-tailed distributions. For α larger than a critical value α^{*}=1+1/γ≤2, the 1/N decay is recovered. We show the practical significance of our results by quantifying the evolution of the English language over the last two centuries using a complete α spectrum of measures. We find that frequent words change more slowly than less frequent words and that α=2 provides the most robust measure to quantify language change.

Identification of similar regions of protein structures using integrated sequence and structure analysis tools

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Heiland Randy

2006-03-01

Full Text Available Abstract Background Understanding protein function from its structure is a challenging problem. Sequence based approaches for finding homology have broad use for annotation of both structure and function. 3D structural information of protein domains and their interactions provide a complementary view to structure function relationships to sequence information. We have developed a web site http://www.sblest.org/ and an API of web services that enables users to submit protein structures and identify statistically significant neighbors and the underlying structural environments that make that match using a suite of sequence and structure analysis tools. To do this, we have integrated S-BLEST, PSI-BLAST and HMMer based superfamily predictions to give a unique integrated view to prediction of SCOP superfamilies, EC number, and GO term, as well as identification of the protein structural environments that are associated with that prediction. Additionally, we have extended UCSF Chimera and PyMOL to support our web services, so that users can characterize their own proteins of interest. Results Users are able to submit their own queries or use a structure already in the PDB. Currently the databases that a user can query include the popular structural datasets ASTRAL 40 v1.69, ASTRAL 95 v1.69, CLUSTER50, CLUSTER70 and CLUSTER90 and PDBSELECT25. The results can be downloaded directly from the site and include function prediction, analysis of the most conserved environments and automated annotation of query proteins. These results reflect both the hits found with PSI-BLAST, HMMer and with S-BLEST. We have evaluated how well annotation transfer can be performed on SCOP ID's, Gene Ontology (GO ID's and EC Numbers. The method is very efficient and totally automated, generally taking around fifteen minutes for a 400 residue protein. Conclusion With structural genomics initiatives determining structures with little, if any, functional characterization

Analysis of high-depth sequence data for studying viral diversity: a comparison of next generation sequencing platforms using Segminator II

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Archer John

2012-03-01

Full Text Available Abstract Background Next generation sequencing provides detailed insight into the variation present within viral populations, introducing the possibility of treatment strategies that are both reactive and predictive. Current software tools, however, need to be scaled up to accommodate for high-depth viral data sets, which are often temporally or spatially linked. In addition, due to the development of novel sequencing platforms and chemistries, each with implicit strengths and weaknesses, it will be helpful for researchers to be able to routinely compare and combine data sets from different platforms/chemistries. In particular, error associated with a specific sequencing process must be quantified so that true biological variation may be identified. Results Segminator II was developed to allow for the efficient comparison of data sets derived from different sources. We demonstrate its usage by comparing large data sets from 12 influenza H1N1 samples sequenced on both the 454 Life Sciences and Illumina platforms, permitting quantification of platform error. For mismatches median error rates at 0.10 and 0.12%, respectively, suggested that both platforms performed similarly. For insertions and deletions median error rates within the 454 data (at 0.3 and 0.2%, respectively were significantly higher than those within the Illumina data (0.004 and 0.006%, respectively. In agreement with previous observations these higher rates were strongly associated with homopolymeric stretches on the 454 platform. Outside of such regions both platforms had similar indel error profiles. Additionally, we apply our software to the identification of low frequency variants. Conclusion We have demonstrated, using Segminator II, that it is possible to distinguish platform specific error from biological variation using data derived from two different platforms. We have used this approach to quantify the amount of error present within the 454 and Illumina platforms in

A behavioral similarity measure between labeled Petri nets based on principal transition sequences

NARCIS (Netherlands)

Wang, J.; He, T.; Wen, L.; Wu, N.; Hofstede, ter A.H.M.; Su, J.; Meersman, R.; Dillon, T.S.; Herrero, P.

2010-01-01

Being able to determine the degree of similarity between process models is important for management, reuse, and analysis of business process models. In this paper we propose a novel method to determine the degree of similarity between process models, which exploits their semantics. Our approach is

Sequence embedding for fast construction of guide trees for multiple sequence alignment

LENUS (Irish Health Repository)

Blackshields, Gordon

2010-05-14

Abstract Background The most widely used multiple sequence alignment methods require sequences to be clustered as an initial step. Most sequence clustering methods require a full distance matrix to be computed between all pairs of sequences. This requires memory and time proportional to N 2 for N sequences. When N grows larger than 10,000 or so, this becomes increasingly prohibitive and can form a significant barrier to carrying out very large multiple alignments. Results In this paper, we have tested variations on a class of embedding methods that have been designed for clustering large numbers of complex objects where the individual distance calculations are expensive. These methods involve embedding the sequences in a space where the similarities within a set of sequences can be closely approximated without having to compute all pair-wise distances. Conclusions We show how this approach greatly reduces computation time and memory requirements for clustering large numbers of sequences and demonstrate the quality of the clusterings by benchmarking them as guide trees for multiple alignment. Source code is available for download from http:\\/\\/www.clustal.org\\/mbed.tgz.

CREST--classification resources for environmental sequence tags.

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Anders Lanzén

Full Text Available Sequencing of taxonomic or phylogenetic markers is becoming a fast and efficient method for studying environmental microbial communities. This has resulted in a steadily growing collection of marker sequences, most notably of the small-subunit (SSU ribosomal RNA gene, and an increased understanding of microbial phylogeny, diversity and community composition patterns. However, to utilize these large datasets together with new sequencing technologies, a reliable and flexible system for taxonomic classification is critical. We developed CREST (Classification Resources for Environmental Sequence Tags, a set of resources and tools for generating and utilizing custom taxonomies and reference datasets for classification of environmental sequences. CREST uses an alignment-based classification method with the lowest common ancestor algorithm. It also uses explicit rank similarity criteria to reduce false positives and identify novel taxa. We implemented this method in a web server, a command line tool and the graphical user interfaced program MEGAN. Further, we provide the SSU rRNA reference database and taxonomy SilvaMod, derived from the publicly available SILVA SSURef, for classification of sequences from bacteria, archaea and eukaryotes. Using cross-validation and environmental datasets, we compared the performance of CREST and SilvaMod to the RDP Classifier. We also utilized Greengenes as a reference database, both with CREST and the RDP Classifier. These analyses indicate that CREST performs better than alignment-free methods with higher recall rate (sensitivity as well as precision, and with the ability to accurately identify most sequences from novel taxa. Classification using SilvaMod performed better than with Greengenes, particularly when applied to environmental sequences. CREST is freely available under a GNU General Public License (v3 from http://apps.cbu.uib.no/crest and http://lcaclassifier.googlecode.com.

Functional similarities between the dictyostelium protein AprA and the human protein dipeptidyl-peptidase IV.

Science.gov (United States)

Herlihy, Sarah E; Tang, Yu; Phillips, Jonathan E; Gomer, Richard H

2017-03-01

Autocrine proliferation repressor protein A (AprA) is a protein secreted by Dictyostelium discoideum cells. Although there is very little sequence similarity between AprA and any human protein, AprA has a predicted structural similarity to the human protein dipeptidyl peptidase IV (DPPIV). AprA is a chemorepellent for Dictyostelium cells, and DPPIV is a chemorepellent for neutrophils. This led us to investigate if AprA and DPPIV have additional functional similarities. We find that like AprA, DPPIV is a chemorepellent for, and inhibits the proliferation of, D. discoideum cells, and that AprA binds some DPPIV binding partners such as fibronectin. Conversely, rAprA has DPPIV-like protease activity. These results indicate a functional similarity between two eukaryotic chemorepellent proteins with very little sequence similarity, and emphasize the usefulness of using a predicted protein structure to search a protein structure database, in addition to searching for proteins with similar sequences. © 2016 The Protein Society.

Functional similarities between the dictyostelium protein AprA and the human protein dipeptidyl‐peptidase IV

Science.gov (United States)

Herlihy, Sarah E.; Tang, Yu; Phillips, Jonathan E.

2017-01-01

Abstract Autocrine proliferation repressor protein A (AprA) is a protein secreted by Dictyostelium discoideum cells. Although there is very little sequence similarity between AprA and any human protein, AprA has a predicted structural similarity to the human protein dipeptidyl peptidase IV (DPPIV). AprA is a chemorepellent for Dictyostelium cells, and DPPIV is a chemorepellent for neutrophils. This led us to investigate if AprA and DPPIV have additional functional similarities. We find that like AprA, DPPIV is a chemorepellent for, and inhibits the proliferation of, D. discoideum cells, and that AprA binds some DPPIV binding partners such as fibronectin. Conversely, rAprA has DPPIV‐like protease activity. These results indicate a functional similarity between two eukaryotic chemorepellent proteins with very little sequence similarity, and emphasize the usefulness of using a predicted protein structure to search a protein structure database, in addition to searching for proteins with similar sequences. PMID:28028841

Full-length genome sequence analysis of four subgroup J avian leukosis virus strains isolated from chickens with clinical hemangioma.

Science.gov (United States)

Lin, Lulu; Wang, Peikun; Yang, Yongli; Li, Haijuan; Huang, Teng; Wei, Ping

2017-12-01

Since 2014, cases of hemangioma associated with avian leukosis virus subgroup J (ALV-J) have been emerging in commercial chickens in Guangxi. In this study, four strains of the subgroup J avian leukosis virus (ALV-J), named GX14HG01, GX14HG04, GX14LT07, and GX14ZS14, were isolated from chickens with clinical hemangioma in 2014 by DF-1 cell culture and then identified with ELISA detection of ALV group specific antigen p27, the detection of subtype specific PCR and indirect immunofluorescence assay (IFA) with ALV-J specific monoclonal antibody. The complete genomes of the isolates were sequenced and it was found that the gag and pol were relatively conservative, while env was variable especially the gp85 gene. Homology analysis of the env gene sequences showed that the env gene of all the four isolates had higher similarities with the hemangioma (HE)-type reference strains than that of the myeloid leukosis (ML)-type strains, and moreover, the HE-type strains' specific deletion of 205-bp sequence covering the rTM and DR1 in 3'UTR fragment was also found in the four isolates. Further analysis on the sequences of subunits of env gene revealed an interesting finding: the gp85 of isolates GX14ZS14 and GX14HG04 had a higher similarity with HPRS-103 and much lower similarity with the HE-type reference strains resulting in GX14ZS14, GX14HG04, and HPRS-103 being clustered in the same branch, while gp37 had higher similarities with the HE-type reference strains when compared to that of HPRS-103, resulted in GX14ZS14, GX14HG04, and HE-type reference strains being clustered in the same branch. The results suggested that isolates GX14ZS14 and GX14HG04 may be the recombinant strains of the foreign strain HPRS-103 with the local epidemic HE-type strains of ALV-J.

A Comparison of Molecular Typing Methods Applied to Enterobacter cloacae complex: hsp60 Sequencing, Rep-PCR, and MLST

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Roberto Viau

2017-02-01

Full Text Available Molecular typing using repetitive sequenced-based PCR (rep-PCR and hsp60 sequencing were applied to a collection of diverse Enterobacter cloacae complex isolates. To determine the most practical method for reference laboratories, we analyzed 71 E. cloacae complex isolates from sporadic and outbreak occurrences originating from 4 geographic areas. While rep-PCR was more discriminating, hsp60 sequencing provided a broader and a more objective geographical tracking method similar to multilocus sequence typing (MLST. In addition, we suggest that MLST may have higher discriminative power compared to hsp60 sequencing, although rep-PCR remains the most discriminative method for local outbreak investigations. In addition, rep-PCR can be an effective and inexpensive method for local outbreak investigation.

BSSF: a fingerprint based ultrafast binding site similarity search and function analysis server

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Jiang Hualiang

2010-01-01

Full Text Available Abstract Background Genome sequencing and post-genomics projects such as structural genomics are extending the frontier of the study of sequence-structure-function relationship of genes and their products. Although many sequence/structure-based methods have been devised with the aim of deciphering this delicate relationship, there still remain large gaps in this fundamental problem, which continuously drives researchers to develop novel methods to extract relevant information from sequences and structures and to infer the functions of newly identified genes by genomics technology. Results Here we present an ultrafast method, named BSSF(Binding Site Similarity & Function, which enables researchers to conduct similarity searches in a comprehensive three-dimensional binding site database extracted from PDB structures. This method utilizes a fingerprint representation of the binding site and a validated statistical Z-score function scheme to judge the similarity between the query and database items, even if their similarities are only constrained in a sub-pocket. This fingerprint based similarity measurement was also validated on a known binding site dataset by comparing with geometric hashing, which is a standard 3D similarity method. The comparison clearly demonstrated the utility of this ultrafast method. After conducting the database searching, the hit list is further analyzed to provide basic statistical information about the occurrences of Gene Ontology terms and Enzyme Commission numbers, which may benefit researchers by helping them to design further experiments to study the query proteins. Conclusions This ultrafast web-based system will not only help researchers interested in drug design and structural genomics to identify similar binding sites, but also assist them by providing further analysis of hit list from database searching.

Remarkable sequence similarity between the dinoflagellate-infecting marine girus and the terrestrial pathogen African swine fever virus

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Claverie Jean-Michel

2009-10-01

Full Text Available Abstract Heterocapsa circularisquama DNA virus (HcDNAV; previously designated as HcV is a giant virus (girus with a ~356-kbp double-stranded DNA (dsDNA genome. HcDNAV lytically infects the bivalve-killing marine dinoflagellate H. circularisquama, and currently represents the sole DNA virus isolated from dinoflagellates, one of the most abundant protists in marine ecosystems. Its morphological features, genome type, and host range previously suggested that HcDNAV might be a member of the family Phycodnaviridae of Nucleo-Cytoplasmic Large DNA Viruses (NCLDVs, though no supporting sequence data was available. NCLDVs currently include two families found in aquatic environments (Phycodnaviridae, Mimiviridae, one mostly infecting terrestrial animals (Poxviridae, another isolated from fish, amphibians and insects (Iridoviridae, and the last one (Asfarviridae exclusively represented by the animal pathogen African swine fever virus (ASFV, the agent of a fatal hemorrhagic disease in domestic swine. In this study, we determined the complete sequence of the type B DNA polymerase (PolB gene of HcDNAV. The viral PolB was transcribed at least from 6 h post inoculation (hpi, suggesting its crucial function for viral replication. Most unexpectedly, the HcDNAV PolB sequence was found to be closely related to the PolB sequence of ASFV. In addition, the amino acid sequence of HcDNAV PolB showed a rare amino acid substitution within a motif containing highly conserved motif: YSDTDS was found in HcDNAV PolB instead of YGDTDS in most dsDNA viruses. Together with the previous observation of ASFV-like sequences in the Sorcerer II Global Ocean Sampling metagenomic datasets, our results further reinforce the ideas that the terrestrial ASFV has its evolutionary origin in marine environments.

Predicting drug-target interaction for new drugs using enhanced similarity measures and super-target clustering.

Science.gov (United States)

Shi, Jian-Yu; Yiu, Siu-Ming; Li, Yiming; Leung, Henry C M; Chin, Francis Y L

2015-07-15

Predicting drug-target interaction using computational approaches is an important step in drug discovery and repositioning. To predict whether there will be an interaction between a drug and a target, most existing methods identify similar drugs and targets in the database. The prediction is then made based on the known interactions of these drugs and targets. This idea is promising. However, there are two shortcomings that have not yet been addressed appropriately. Firstly, most of the methods only use 2D chemical structures and protein sequences to measure the similarity of drugs and targets respectively. However, this information may not fully capture the characteristics determining whether a drug will interact with a target. Secondly, there are very few known interactions, i.e. many interactions are "missing" in the database. Existing approaches are biased towards known interactions and have no good solutions to handle possibly missing interactions which affect the accuracy of the prediction. In this paper, we enhance the similarity measures to include non-structural (and non-sequence-based) information and introduce the concept of a "super-target" to handle the problem of possibly missing interactions. Based on evaluations on real data, we show that our similarity measure is better than the existing measures and our approach is able to achieve higher accuracy than the two best existing algorithms, WNN-GIP and KBMF2K. Our approach is available at http://web.hku.hk/∼liym1018/projects/drug/drug.html or http://www.bmlnwpu.org/us/tools/PredictingDTI_S2/METHODS.html. Copyright © 2015 Elsevier Inc. All rights reserved.

A software pipeline for processing and identification of fungal ITS sequences

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Kristiansson Erik

2009-01-01

Full Text Available Abstract Background Fungi from environmental samples are typically identified to species level through DNA sequencing of the nuclear ribosomal internal transcribed spacer (ITS region for use in BLAST-based similarity searches in the International Nucleotide Sequence Databases. These searches are time-consuming and regularly require a significant amount of manual intervention and complementary analyses. We here present software – in the form of an identification pipeline for large sets of fungal ITS sequences – developed to automate the BLAST process and several additional analysis steps. The performance of the pipeline was evaluated on a dataset of 350 ITS sequences from fungi growing as epiphytes on building material. Results The pipeline was written in Perl and uses a local installation of NCBI-BLAST for the similarity searches of the query sequences. The variable subregion ITS2 of the ITS region is extracted from the sequences and used for additional searches of higher sensitivity. Multiple alignments of each query sequence and its closest matches are computed, and query sequences sharing at least 50% of their best matches are clustered to facilitate the evaluation of hypothetically conspecific groups. The pipeline proved to speed up the processing, as well as enhance the resolution, of the evaluation dataset considerably, and the fungi were found to belong chiefly to the Ascomycota, with Penicillium and Aspergillus as the two most common genera. The ITS2 was found to indicate a different taxonomic affiliation than did the complete ITS region for 10% of the query sequences, though this figure is likely to vary with the taxonomic scope of the query sequences. Conclusion The present software readily assigns large sets of fungal query sequences to their respective best matches in the international sequence databases and places them in a larger biological context. The output is highly structured to be easy to process, although it still needs

Characterization of human MMTV-like (HML) elements similar to a sequence that was highly expressed in a human breast cancer: further definition of the HML-6 group.

Science.gov (United States)

Yin, H; Medstrand, P; Kristofferson, A; Dietrich, U; Aman, P; Blomberg, J

1999-03-30

Previously, we found a retroviral sequence, HML-6.2BC1, to be expressed at high levels in a multifocal ductal breast cancer from a 41-year-old woman who also developed ovarian carcinoma. The sequence of a human genomic clone (HML-6.28) selected by high-stringency hybridization with HML-6.2BC1 is reported here. It was 99% identical to HML-6.2BC1 and gave the same restriction fragments as total DNA. HML-6.28 is a 4.7-kb provirus with a 5'LTR, truncated in RT. Data from two similar genomic clones and sequences found in GenBank are also reported. Overlaps between them gave a rather complete picture of the HML-6.2BC1-like human endogenous retroviral elements. Work with somatic cell hybrids and FISH localized HML-6.28 to chromosome 6, band p21, close to the MHC region. The causal role of HML-6.28 in breast cancer remains unclear. Nevertheless, the ca. 20 Myr old HML-6 sequences enabled the definition of common and unique features of type A, B, and D (ABD) retroviruses. In Gag, HML-6 has no intervening sequences between matrix and capsid proteins, unlike extant exogenous ABD viruses, possibly an ancestral feature. Alignment of the dUTPase showed it to be present in all ABD viruses, but gave a phylogenetic tree different from trees made from other ABD genes, indicating a distinct phylogeny of dUTPase. A conserved 24-mer sequence in the amino terminus of some ABD envelope genes suggested a conserved function. Copyright 1999 Academic Press.

Lineup member similarity effects on children's eyewitness identification

OpenAIRE

Fitzgerald, Ryan J.; Whiting, Brittany F.; Therrien, Natalie M.; Price, Heather L.

2014-01-01

To date, research investigating the similarity among lineup members has focused on adult eyewitnesses. In the present research, children made identifications from lineups containing members of lower or higher similarity to a target person. In Experiment 1, following a live interaction, children's (6–14 years) correct identification rate was reduced in higher-similarity relative to lower-similarity lineups. In Experiment 2, children (6–12 years) and adults watched a video containing a target p...

Short sequence motifs, overrepresented in mammalian conservednon-coding sequences

Energy Technology Data Exchange (ETDEWEB)

Minovitsky, Simon; Stegmaier, Philip; Kel, Alexander; Kondrashov,Alexey S.; Dubchak, Inna

2007-02-21

Background: A substantial fraction of non-coding DNAsequences of multicellular eukaryotes is under selective constraint. Inparticular, ~;5 percent of the human genome consists of conservednon-coding sequences (CNSs). CNSs differ from other genomic sequences intheir nucleotide composition and must play important functional roles,which mostly remain obscure.Results: We investigated relative abundancesof short sequence motifs in all human CNSs present in the human/mousewhole-genome alignments vs. three background sets of sequences: (i)weakly conserved or unconserved non-coding sequences (non-CNSs); (ii)near-promoter sequences (located between nucleotides -500 and -1500,relative to a start of transcription); and (iii) random sequences withthe same nucleotide composition as that of CNSs. When compared tonon-CNSs and near-promoter sequences, CNSs possess an excess of AT-richmotifs, often containing runs of identical nucleotides. In contrast, whencompared to random sequences, CNSs contain an excess of GC-rich motifswhich, however, lack CpG dinucleotides. Thus, abundance of short sequencemotifs in human CNSs, taken as a whole, is mostly determined by theiroverall compositional properties and not by overrepresentation of anyspecific short motifs. These properties are: (i) high AT-content of CNSs,(ii) a tendency, probably due to context-dependent mutation, of A's andT's to clump, (iii) presence of short GC-rich regions, and (iv) avoidanceof CpG contexts, due to their hypermutability. Only a small number ofshort motifs, overrepresented in all human CNSs are similar to bindingsites of transcription factors from the FOX family.Conclusion: Human CNSsas a whole appear to be too broad a class of sequences to possess strongfootprints of any short sequence-specific functions. Such footprintsshould be studied at the level of functional subclasses of CNSs, such asthose which flank genes with a particular pattern of expression. Overallproperties of CNSs are affected by

Static multiplicities in heterogeneous azeotropic distillation sequences

DEFF Research Database (Denmark)

Esbjerg, Klavs; Andersen, Torben Ravn; Jørgensen, Sten Bay

1998-01-01

In this paper the results of a bifurcation analysis on heterogeneous azeotropic distillation sequences are given. Two sequences suitable for ethanol dehydration are compared: The 'direct' and the 'indirect' sequence. It is shown, that the two sequences, despite their similarities, exhibit very...... different static behavior. The method of Petlyuk and Avet'yan (1971), Bekiaris et al. (1993), which assumes infinite reflux and infinite number of stages, is extended to and applied on heterogeneous azeotropic distillation sequences. The predictions are substantiated through simulations. The static sequence...

Analysis of xylem formation in pine by cDNA sequencing

Science.gov (United States)

Allona, I.; Quinn, M.; Shoop, E.; Swope, K.; St Cyr, S.; Carlis, J.; Riedl, J.; Retzel, E.; Campbell, M. M.; Sederoff, R.;

Evaluation of the reproducibility of amplicon sequencing with Illumina MiSeq platform.

Science.gov (United States)

Wen, Chongqing; Wu, Liyou; Qin, Yujia; Van Nostrand, Joy D; Ning, Daliang; Sun, Bo; Xue, Kai; Liu, Feifei; Deng, Ye; Liang, Yuting; Zhou, Jizhong

2017-01-01

Illumina's MiSeq has become the dominant platform for gene amplicon sequencing in microbial ecology studies; however, various technical concerns, such as reproducibility, still exist. To assess reproducibility, 16S rRNA gene amplicons from 18 soil samples of a reciprocal transplantation experiment were sequenced on an Illumina MiSeq. The V4 region of 16S rRNA gene from each sample was sequenced in triplicate with each replicate having a unique barcode. The average OTU overlap, without considering sequence abundance, at a rarefaction level of 10,323 sequences was 33.4±2.1% and 20.2±1.7% between two and among three technical replicates, respectively. When OTU sequence abundance was considered, the average sequence abundance weighted OTU overlap was 85.6±1.6% and 81.2±2.1% for two and three replicates, respectively. Removing singletons significantly increased the overlap for both (~1-3%, pdeep sequencing increased OTU overlap both when sequence abundance was considered (95%) and when not (44%). However, if singletons were not removed the overlap between two technical replicates (not considering sequence abundance) plateaus at 39% with 30,000 sequences. Diversity measures were not affected by the low overlap as α-diversities were similar among technical replicates while β-diversities (Bray-Curtis) were much smaller among technical replicates than among treatment replicates (e.g., 0.269 vs. 0.374). Higher diversity coverage, but lower OTU overlap, was observed when replicates were sequenced in separate runs. Detrended correspondence analysis indicated that while there was considerable variation among technical replicates, the reproducibility was sufficient for detecting treatment effects for the samples examined. These results suggest that although there is variation among technical replicates, amplicon sequencing on MiSeq is useful for analyzing microbial community structure if used appropriately and with caution. For example, including technical replicates

Comparative genome sequencing of drosophila pseudoobscura: Chromosomal, gene and cis-element evolution

Energy Technology Data Exchange (ETDEWEB)

Richards, Stephen; Liu, Yue; Bettencourt, Brian R.; Hradecky, Pavel; Letovsky, Stan; Nielsen, Rasmus; Thornton, Kevin; Todd, Melissa J.; Chen, Rui; Meisel, Richard P.; Couronne, Olivier; Hua, Sujun; Smith, Mark A.; Bussemaker, Harmen J.; van Batenburg, Marinus F.; Howells, Sally L.; Scherer, Steven E.; Sodergren, Erica; Matthews, Beverly B.; Crosby, Madeline A.; Schroeder, Andrew J.; Ortiz-Barrientos, Daniel; Rives, Catherine M.; Metzker, Michael L.; Muzny, Donna M.; Scott, Graham; Steffen, David; Wheeler, David A.; Worley, Kim C.; Havlak, Paul; Durbin, K. James; Egan, Amy; Gill, Rachel; Hume, Jennifer; Morgan, Margaret B.; Miner, George; Hamilton, Cerissa; Huang, Yanmei; Waldron, Lenee; Verduzco, Daniel; Blankenburg, Kerstin P.; Dubchak, Inna; Noor, Mohamed A.F.; Anderson, Wyatt; White, Kevin P.; Clark, Andrew G.; Schaeffer, Stephen W.; Gelbart, William; Weinstock, George M.; Gibbs, Richard A.

2004-04-01

The genome sequence of a second fruit fly, D. pseudoobscura, presents an opportunity for comparative analysis of a primary model organism D. melanogaster. The vast majority of Drosophila genes have remained on the same arm, but within each arm gene order has been extensively reshuffled leading to the identification of approximately 1300 syntenic blocks. A repetitive sequence is found in the D. pseudoobscura genome at many junctions between adjacent syntenic blocks. Analysis of this novel repetitive element family suggests that recombination between offset elements may have given rise to many paracentric inversions, thereby contributing to the shuffling of gene order in the D. pseudoobscura lineage. Based on sequence similarity and synteny, 10,516 putative orthologs have been identified as a core gene set conserved over 35 My since divergence. Genes expressed in the testes had higher amino acid sequence divergence than the genome wide average consistent with the rapid evolution of sex-specific proteins. Cis-regulatory sequences are more conserved than control sequences between the species but the difference is slight, suggesting that the evolution of cis-regulatory elements is flexible. Overall, a picture of repeat mediated chromosomal rearrangement, and high co-adaptation of both male genes and cis-regulatory sequences emerges as important themes of genome divergence between these species of Drosophila.

Sequencing of BAC pools by different next generation sequencing platforms and strategies

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Scholz Uwe

2011-10-01

Full Text Available Abstract Background Next generation sequencing of BACs is a viable option for deciphering the sequence of even large and highly repetitive genomes. In order to optimize this strategy, we examined the influence of read length on the quality of Roche/454 sequence assemblies, to what extent Illumina/Solexa mate pairs (MPs improve the assemblies by scaffolding and whether barcoding of BACs is dispensable. Results Sequencing four BACs with both FLX and Titanium technologies revealed similar sequencing accuracy, but showed that the longer Titanium reads produce considerably less misassemblies and gaps. The 454 assemblies of 96 barcoded BACs were improved by scaffolding 79% of the total contig length with MPs from a non-barcoded library. Assembly of the unmasked 454 sequences without separation by barcodes revealed chimeric contig formation to be a major problem, encompassing 47% of the total contig length. Masking the sequences reduced this fraction to 24%. Conclusion Optimal BAC pool sequencing should be based on the longest available reads, with barcoding essential for a comprehensive assessment of both repetitive and non-repetitive sequence information. When interest is restricted to non-repetitive regions and repeats are masked prior to assembly, barcoding is non-essential. In any case, the assemblies can be improved considerably by scaffolding with non-barcoded BAC pool MPs.

Genomic sequence around butterfly wing development genes: annotation and comparative analysis.

Directory of Open Access Journals (Sweden)

Inês C Conceição

Full Text Available BACKGROUND: Analysis of genomic sequence allows characterization of genome content and organization, and access beyond gene-coding regions for identification of functional elements. BAC libraries, where relatively large genomic regions are made readily available, are especially useful for species without a fully sequenced genome and can increase genomic coverage of phylogenetic and biological diversity. For example, no butterfly genome is yet available despite the unique genetic and biological properties of this group, such as diversified wing color patterns. The evolution and development of these patterns is being studied in a few target species, including Bicyclus anynana, where a whole-genome BAC library allows targeted access to large genomic regions. METHODOLOGY/PRINCIPAL FINDINGS: We characterize ∼1.3 Mb of genomic sequence around 11 selected genes expressed in B. anynana developing wings. Extensive manual curation of in silico predictions, also making use of a large dataset of expressed genes for this species, identified repetitive elements and protein coding sequence, and highlighted an expansion of Alcohol dehydrogenase genes. Comparative analysis with orthologous regions of the lepidopteran reference genome allowed assessment of conservation of fine-scale synteny (with detection of new inversions and translocations and of DNA sequence (with detection of high levels of conservation of non-coding regions around some, but not all, developmental genes. CONCLUSIONS: The general properties and organization of the available B. anynana genomic sequence are similar to the lepidopteran reference, despite the more than 140 MY divergence. Our results lay the groundwork for further studies of new interesting findings in relation to both coding and non-coding sequence: 1 the Alcohol dehydrogenase expansion with higher similarity between the five tandemly-repeated B. anynana paralogs than with the corresponding B. mori orthologs, and 2 the high

Whole-body magnetic resonance imaging for staging and follow-up of pediatric patients with Hodgkin's lymphoma: comparison of different sequences

International Nuclear Information System (INIS)

Nava, Daniel; Oliveira, Heverton Cesar de

2011-01-01

Objective: to compare the performance of the T1, T2, STIR and DWIBS (diffusion-weighted whole-body imaging with background body signal suppression) sequences in the staging and follow-up of pediatric patients with Hodgkin's lymphoma in lymph node chains, parenchymal organs and bone marrow, and to evaluate interobserver agreement. Materials and methods: the authors studied 12 patients with confirmed diagnosis of Hodgkin's lymphoma. The patients were referred for whole body magnetic resonance imaging with T1-weighted, T2-weighted, STIR and DWIBS sequences. Results: the number of lymph node sites characterized as affected by the disease on T1- and T2-weighted sequences showed similar results (8 sites for both sequences), but lower than DWIBS and STIR sequences (11 and 12 sites, respectively). The bone marrow involvement by lymphoma showed the same values for the T1-, T2-weighted and DWIBS sequences (17 lesions), higher than the value found on STIR (13 lesions). A high rate of interobserver agreement was observed as the four sequences were analyzed. Conclusion: STIR and DWIBS sequences detected the highest number of lymph node sites characterized as affected by the disease. Similar results were demonstrated by all the sequences in the evaluation of parenchymal organs and bone marrow. A high interobserver agreement was observed as the four sequences were analyzed. (author)

Protein secondary structure prediction for a single-sequence using hidden semi-Markov models

Directory of Open Access Journals (Sweden)

Borodovsky Mark

2006-03-01

Full Text Available Abstract Background The accuracy of protein secondary structure prediction has been improving steadily towards the 88% estimated theoretical limit. There are two types of prediction algorithms: Single-sequence prediction algorithms imply that information about other (homologous proteins is not available, while algorithms of the second type imply that information about homologous proteins is available, and use it intensively. The single-sequence algorithms could make an important contribution to studies of proteins with no detected homologs, however the accuracy of protein secondary structure prediction from a single-sequence is not as high as when the additional evolutionary information is present. Results In this paper, we further refine and extend the hidden semi-Markov model (HSMM initially considered in the BSPSS algorithm. We introduce an improved residue dependency model by considering the patterns of statistically significant amino acid correlation at structural segment borders. We also derive models that specialize on different sections of the dependency structure and incorporate them into HSMM. In addition, we implement an iterative training method to refine estimates of HSMM parameters. The three-state-per-residue accuracy and other accuracy measures of the new method, IPSSP, are shown to be comparable or better than ones for BSPSS as well as for PSIPRED, tested under the single-sequence condition. Conclusions We have shown that new dependency models and training methods bring further improvements to single-sequence protein secondary structure prediction. The results are obtained under cross-validation conditions using a dataset with no pair of sequences having significant sequence similarity. As new sequences are added to the database it is possible to augment the dependency structure and obtain even higher accuracy. Current and future advances should contribute to the improvement of function prediction for orphan proteins inscrutable

Genome Sequence Databases (Overview): Sequencing and Assembly

Energy Technology Data Exchange (ETDEWEB)

Lapidus, Alla L.

2009-01-01

From the date its role in heredity was discovered, DNA has been generating interest among scientists from different fields of knowledge: physicists have studied the three dimensional structure of the DNA molecule, biologists tried to decode the secrets of life hidden within these long molecules, and technologists invent and improve methods of DNA analysis. The analysis of the nucleotide sequence of DNA occupies a special place among the methods developed. Thanks to the variety of sequencing technologies available, the process of decoding the sequence of genomic DNA (or whole genome sequencing) has become robust and inexpensive. Meanwhile the assembly of whole genome sequences remains a challenging task. In addition to the need to assemble millions of DNA fragments of different length (from 35 bp (Solexa) to 800 bp (Sanger)), great interest in analysis of microbial communities (metagenomes) of different complexities raises new problems and pushes some new requirements for sequence assembly tools to the forefront. The genome assembly process can be divided into two steps: draft assembly and assembly improvement (finishing). Despite the fact that automatically performed assembly (or draft assembly) is capable of covering up to 98% of the genome, in most cases, it still contains incorrectly assembled reads. The error rate of the consensus sequence produced at this stage is about 1/2000 bp. A finished genome represents the genome assembly of much higher accuracy (with no gaps or incorrectly assembled areas) and quality ({approx}1 error/10,000 bp), validated through a number of computer and laboratory experiments.

Pulmonary parenchyma segmentation in thin CT image sequences with spectral clustering and geodesic active contour model based on similarity

Science.gov (United States)

He, Nana; Zhang, Xiaolong; Zhao, Juanjuan; Zhao, Huilan; Qiang, Yan

2017-07-01

While the popular thin layer scanning technology of spiral CT has helped to improve diagnoses of lung diseases, the large volumes of scanning images produced by the technology also dramatically increase the load of physicians in lesion detection. Computer-aided diagnosis techniques like lesions segmentation in thin CT sequences have been developed to address this issue, but it remains a challenge to achieve high segmentation efficiency and accuracy without much involvement of human manual intervention. In this paper, we present our research on automated segmentation of lung parenchyma with an improved geodesic active contour model that is geodesic active contour model based on similarity (GACBS). Combining spectral clustering algorithm based on Nystrom (SCN) with GACBS, this algorithm first extracts key image slices, then uses these slices to generate an initial contour of pulmonary parenchyma of un-segmented slices with an interpolation algorithm, and finally segments lung parenchyma of un-segmented slices. Experimental results show that the segmentation results generated by our method are close to what manual segmentation can produce, with an average volume overlap ratio of 91.48%.

Integration of Phenotypic Metadata and Protein Similarity in Archaea Using a Spectral Bipartitioning Approach

Energy Technology Data Exchange (ETDEWEB)

Hooper, Sean D.; Anderson, Iain J; Pati, Amrita; Dalevi, Daniel; Mavromatis, Konstantinos; Kyrpides, Nikos C

2009-01-01

In order to simplify and meaningfully categorize large sets of protein sequence data, it is commonplace to cluster proteins based on the similarity of those sequences. However, it quickly becomes clear that the sequence flexibility allowed a given protein varies significantly among different protein families. The degree to which sequences are conserved not only differs for each protein family, but also is affected by the phylogenetic divergence of the source organisms. Clustering techniques that use similarity thresholds for protein families do not always allow for these variations and thus cannot be confidently used for applications such as automated annotation and phylogenetic profiling. In this work, we applied a spectral bipartitioning technique to all proteins from 53 archaeal genomes. Comparisons between different taxonomic levels allowed us to study the effects of phylogenetic distances on cluster structure. Likewise, by associating functional annotations and phenotypic metadata with each protein, we could compare our protein similarity clusters with both protein function and associated phenotype. Our clusters can be analyzed graphically and interactively online.

Lower prevalence but similar fitness in a parasitic fungus at higher radiation levels near Chernobyl.

Science.gov (United States)

Aguileta, Gabriela; Badouin, Helene; Hood, Michael E; Møller, Anders P; Le Prieur, Stephanie; Snirc, Alodie; Siguenza, Sophie; Mousseau, Timothy A; Shykoff, Jacqui A; Cuomo, Christina A; Giraud, Tatiana

2016-07-01

Nuclear disasters at Chernobyl and Fukushima provide examples of effects of acute ionizing radiation on mutations that can affect the fitness and distribution of species. Here, we investigated the prevalence of Microbotryum lychnidis-dioicae, a pollinator-transmitted fungal pathogen of plants causing anther-smut disease in Chernobyl, its viability, fertility and karyotype variation, and the accumulation of nonsynonymous mutations in its genome. We collected diseased flowers of Silene latifolia from locations ranging by more than two orders of magnitude in background radiation, from 0.05 to 21.03 μGy/h. Disease prevalence decreased significantly with increasing radiation level, possibly due to lower pollinator abundance and altered pollinator behaviour. Viability and fertility, measured as the budding rate of haploid sporidia following meiosis from the diploid teliospores, did not vary with increasing radiation levels and neither did karyotype overall structure and level of chromosomal size heterozygosity. We sequenced the genomes of twelve samples from Chernobyl and of four samples collected from uncontaminated areas and analysed alignments of 6068 predicted genes, corresponding to 1.04 × 10(7)  base pairs. We found no dose-dependent differences in substitution rates (neither dN, dS, nor dN/dS). Thus, we found no significant evidence of increased deleterious mutation rates at higher levels of background radiation in this plant pathogen. We even found lower levels of nonsynonymous substitution rates in contaminated areas compared to control regions, suggesting that purifying selection was stronger in contaminated than uncontaminated areas. We briefly discuss the possibilities for a mechanistic basis of radio resistance in this nonmelanized fungus. © 2016 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Structural and sequence analysis of imelysin-like proteins implicated in bacterial iron uptake.

Directory of Open Access Journals (Sweden)

Qingping Xu

Full Text Available Imelysin-like proteins define a superfamily of bacterial proteins that are likely involved in iron uptake. Members of this superfamily were previously thought to be peptidases and were included in the MEROPS family M75. We determined the first crystal structures of two remotely related, imelysin-like proteins. The Psychrobacter arcticus structure was determined at 2.15 Å resolution and contains the canonical imelysin fold, while higher resolution structures from the gut bacteria Bacteroides ovatus, in two crystal forms (at 1.25 Å and 1.44 Å resolution, have a circularly permuted topology. Both structures are highly similar to each other despite low sequence similarity and circular permutation. The all-helical structure can be divided into two similar four-helix bundle domains. The overall structure and the GxHxxE motif region differ from known HxxE metallopeptidases, suggesting that imelysin-like proteins are not peptidases. A putative functional site is located at the domain interface. We have now organized the known homologous proteins into a superfamily, which can be separated into four families. These families share a similar functional site, but each has family-specific structural and sequence features. These results indicate that imelysin-like proteins have evolved from a common ancestor, and likely have a conserved function.

Marriage Matters: Spousal Similarity in Life Satisfaction

OpenAIRE

Ulrich Schimmack; Richard Lucas

2006-01-01

Examined the concurrent and cross-lagged spousal similarity in life satisfaction over a 21-year period. Analyses were based on married couples (N = 847) in the German Socio-Economic Panel (SOEP). Concurrent spousal similarity was considerably higher than one-year retest similarity, revealing spousal similarity in the variable component of life satisfac-tion. Spousal similarity systematically decreased with length of retest interval, revealing simi-larity in the changing component of life sati...

In silico Analysis of 3′-End-Processing Signals in Aspergillus oryzae Using Expressed Sequence Tags and Genomic Sequencing Data

Science.gov (United States)

Tanaka, Mizuki; Sakai, Yoshifumi; Yamada, Osamu; Shintani, Takahiro; Gomi, Katsuya

2011-01-01

To investigate 3′-end-processing signals in Aspergillus oryzae, we created a nucleotide sequence data set of the 3′-untranslated region (3′ UTR) plus 100 nucleotides (nt) sequence downstream of the poly(A) site using A. oryzae expressed sequence tags and genomic sequencing data. This data set comprised 1065 sequences derived from 1042 unique genes. The average 3′ UTR length in A. oryzae was 241 nt, which is greater than that in yeast but similar to that in plants. The 3′ UTR and 100 nt sequence downstream of the poly(A) site is notably U-rich, while the region located 15–30 nt upstream of the poly(A) site is markedly A-rich. The most frequently found hexanucleotide in this A-rich region is AAUGAA, although this sequence accounts for only 6% of all transcripts. These data suggested that A. oryzae has no highly conserved sequence element equivalent to AAUAAA, a mammalian polyadenylation signal. We identified that putative 3′-end-processing signals in A. oryzae, while less well conserved than those in mammals, comprised four sequence elements: the furthest upstream U-rich element, A-rich sequence, cleavage site, and downstream U-rich element flanking the cleavage site. Although these putative 3′-end-processing signals are similar to those in yeast and plants, some notable differences exist between them. PMID:21586533

Sleep and memory consolidation: motor performance and proactive interference effects in sequence learning.

Science.gov (United States)

Borragán, Guillermo; Urbain, Charline; Schmitz, Rémy; Mary, Alison; Peigneux, Philippe

2015-04-01

That post-training sleep supports the consolidation of sequential motor skills remains debated. Performance improvement and sensitivity to proactive interference are both putative measures of long-term memory consolidation. We tested sleep-dependent memory consolidation for visuo-motor sequence learning using a proactive interference paradigm. Thirty-three young adults were trained on sequence A on Day 1, then had Regular Sleep (RS) or were Sleep Deprived (SD) on the night after learning. After two recovery nights, they were tested on the same sequence A, then had to learn a novel, potentially competing sequence B. We hypothesized that proactive interference effects on sequence B due to the prior learning of sequence A would be higher in the RS condition, considering that proactive interference is an indirect marker of the robustness of sequence A, which should be better consolidated over post-training sleep. Results highlighted sleep-dependent improvement for sequence A, with faster RTs overnight for RS participants only. Moreover, the beneficial impact of sleep was specific to the consolidation of motor but not sequential skills. Proactive interference effects on learning a new material at Day 4 were similar between RS and SD participants. These results suggest that post-training sleep contributes to optimizing motor but not sequential components of performance in visuo-motor sequence learning. Copyright © 2015 Elsevier Inc. All rights reserved.

Entropic fluctuations in DNA sequences

Science.gov (United States)

Thanos, Dimitrios; Li, Wentian; Provata, Astero

2018-03-01

The Local Shannon Entropy (LSE) in blocks is used as a complexity measure to study the information fluctuations along DNA sequences. The LSE of a DNA block maps the local base arrangement information to a single numerical value. It is shown that despite this reduction of information, LSE allows to extract meaningful information related to the detection of repetitive sequences in whole chromosomes and is useful in finding evolutionary differences between organisms. More specifically, large regions of tandem repeats, such as centromeres, can be detected based on their low LSE fluctuations along the chromosome. Furthermore, an empirical investigation of the appropriate block sizes is provided and the relationship of LSE properties with the structure of the underlying repetitive units is revealed by using both computational and mathematical methods. Sequence similarity between the genomic DNA of closely related species also leads to similar LSE values at the orthologous regions. As an application, the LSE covariance function is used to measure the evolutionary distance between several primate genomes.

ON SOME RECURRENCE TYPE SMARANDACHE SEQUENCES

OpenAIRE

MAJUMDAR, A.A.K.; GUNARTO, H.

2000-01-01

In this paper, we study some properties of ten recurrence type Smarandache sequences, namely, the Smarandache odd, even, prime product, square product, higher-power product, permutation, consecutive, reverse, symmetric, and pierced chain sequences.

A HIGHER EFFICIENCY OF CONVERTING GAS TO STARS PUSHES GALAXIES AT z ∼ 1.6 WELL ABOVE THE STAR-FORMING MAIN SEQUENCE

Energy Technology Data Exchange (ETDEWEB)

Silverman, J. D.; Rujopakarn, W. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Daddi, E.; Liu, D. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay (France); Rodighiero, G. [Dipartimento di Fisica e Astronomia, Universita di Padova, vicolo Osservatorio, 3, I-35122 Padova (Italy); Sargent, M. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Renzini, A. [Instituto Nazionale de Astrofisica, Osservatorio Astronomico di Padova, v.co dell’Osservatorio 5, I-35122 Padova (Italy); Feruglio, C. [IRAM—Institut de RadioAstronomie Millimétrique, 300 rue de la Piscine, F-38406 Saint Martin d’Hères (France); Kashino, D. [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya 464-8602 (Japan); Sanders, D. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Kartaltepe, J. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Nagao, T. [Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan); Arimoto, N. [Subaru Telescope, 650 North A’ohoku Place, Hilo, HI-96720 (United States); Berta, S.; Lutz, D. [Max-Planck-Institut für extraterrestrische Physik, D-84571 Garching (Germany); Béthermin, M. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Koekemoer, A., E-mail: john.silverman@ipmu.jp [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218 (United States); and others

2015-10-20

Local starbursts have a higher efficiency of converting gas into stars, as compared to typical star-forming galaxies at a given stellar mass, possibly indicative of different modes of star formation. With the peak epoch of galaxy formation occurring at z > 1, it remains to be established whether such an efficient mode of star formation is occurring at high redshift. To address this issue, we measure the molecular gas content of seven high-redshift (z ∼ 1.6) starburst galaxies with the Atacama Large Millimeter/submillimeter Array and IRAM/Plateau de Bure Interferometer. Our targets are selected from the sample of Herschel far-infrared-detected galaxies having star formation rates (∼300–800 M{sub ⊙} yr{sup −1}) elevated (≳4×) above the star-forming main sequence (MS) and included in the FMOS-COSMOS near-infrared spectroscopic survey of star-forming galaxies at z ∼ 1.6 with Subaru. We detect CO emission in all cases at high levels of significance, indicative of high gas fractions (∼30%–50%). Even more compelling, we firmly establish with a clean and systematic selection that starbursts, identified as MS outliers, at high redshift generally have a lower ratio of CO to total infrared luminosity as compared to typical MS star-forming galaxies, although with a smaller offset than expected based on past studies of local starbursts. We put forward a hypothesis that there exists a continuous increase in star formation efficiency with elevation from the MS with galaxy mergers as a possible physical driver. Along with a heightened star formation efficiency, our high-redshift sample is similar in other respects to local starbursts, such as being metal rich and having a higher ionization state of the interstellar medium.

Constraint Satisfaction Inference : Non-probabilistic Global Inference for Sequence Labelling

NARCIS (Netherlands)

Canisius, S.V.M.; van den Bosch, A.; Daelemans, W.; Basili, R.; Moschitti, A.

2006-01-01

We present a new method for performing sequence labelling based on the idea of using a machine-learning classifier to generate several possible output sequences, and then applying an inference procedure to select the best sequence among those. Most sequence labelling methods following a similar

Fast discovery and visualization of conserved regions in DNA sequences using quasi-alignment.

Science.gov (United States)

Nagar, Anurag; Hahsler, Michael

2013-01-01

Next Generation Sequencing techniques are producing enormous amounts of biological sequence data and analysis becomes a major computational problem. Currently, most analysis, especially the identification of conserved regions, relies heavily on Multiple Sequence Alignment and its various heuristics such as progressive alignment, whose run time grows with the square of the number and the length of the aligned sequences and requires significant computational resources. In this work, we present a method to efficiently discover regions of high similarity across multiple sequences without performing expensive sequence alignment. The method is based on approximating edit distance between segments of sequences using p-mer frequency counts. Then, efficient high-throughput data stream clustering is used to group highly similar segments into so called quasi-alignments. Quasi-alignments have numerous applications such as identifying species and their taxonomic class from sequences, comparing sequences for similarities, and, as in this paper, discovering conserved regions across related sequences. In this paper, we show that quasi-alignments can be used to discover highly similar segments across multiple sequences from related or different genomes efficiently and accurately. Experiments on a large number of unaligned 16S rRNA sequences obtained from the Greengenes database show that the method is able to identify conserved regions which agree with known hypervariable regions in 16S rRNA. Furthermore, the experiments show that the proposed method scales well for large data sets with a run time that grows only linearly with the number and length of sequences, whereas for existing multiple sequence alignment heuristics the run time grows super-linearly. Quasi-alignment-based algorithms can detect highly similar regions and conserved areas across multiple sequences. Since the run time is linear and the sequences are converted into a compact clustering model, we are able to

Contrasting HIV phylogenetic relationships and V3 loop protein similarities

Energy Technology Data Exchange (ETDEWEB)

Korber, B. (Los Alamos National Lab., NM (United States) Santa Fe Inst., NM (United States)); Myers, G. (Los Alamos National Lab., NM (United States))

1992-01-01

At least five distinct sequence subtypes of HIV-I can be identified from the major centers of the AMS pandemic. While it is too early to tell whether these subtypes are serologically or phenotypically similar or distinct in terms of properties such as pathogenicity and transmissibility, we can begin to investigate their potential for phenotypic divergence at the protein sequence level. Phylogenetic analysis of HIV DNA sequences is being widely used to examine lineages of different viral strains as they evolve and spread throughout the globe. We have identified five distinct HIV-1 subtypes (designated A-E), or clades, based on phylogenetic clustering patterns generated from genetic information from both the gag and envelope (env) genes from a spectrum of international isolates. Our initial observations concerning both HIV-1 and HIV-2 sequences indicate that conserved patterns in protein chemistry may indeed exist across distant lineages. Such patterns in V3 loop amino acid chemistry may be indicative of stable lineages or convergence within this highly variable, though functionally and immunologically critical, region. We think that there may be parallels between the apparently stable HIV-2 V3 lineage and the previously mentioned HIV-1 V3 loops which are very similar at the protein level despite being distant by cladistic analysis, and which do not possess the distinctive positively charged residues. Highly conserved V3 loop protein sequences are also encountered in SIVAGMs and CIVs (chimpanzee viral strains), which do not appear to be pathogenic in their wild-caught natural hosts.

Contrasting HIV phylogenetic relationships and V3 loop protein similarities

Energy Technology Data Exchange (ETDEWEB)

Korber, B. [Los Alamos National Lab., NM (United States)]|[Santa Fe Inst., NM (United States); Myers, G. [Los Alamos National Lab., NM (United States)

1992-12-31

At least five distinct sequence subtypes of HIV-I can be identified from the major centers of the AMS pandemic. While it is too early to tell whether these subtypes are serologically or phenotypically similar or distinct in terms of properties such as pathogenicity and transmissibility, we can begin to investigate their potential for phenotypic divergence at the protein sequence level. Phylogenetic analysis of HIV DNA sequences is being widely used to examine lineages of different viral strains as they evolve and spread throughout the globe. We have identified five distinct HIV-1 subtypes (designated A-E), or clades, based on phylogenetic clustering patterns generated from genetic information from both the gag and envelope (env) genes from a spectrum of international isolates. Our initial observations concerning both HIV-1 and HIV-2 sequences indicate that conserved patterns in protein chemistry may indeed exist across distant lineages. Such patterns in V3 loop amino acid chemistry may be indicative of stable lineages or convergence within this highly variable, though functionally and immunologically critical, region. We think that there may be parallels between the apparently stable HIV-2 V3 lineage and the previously mentioned HIV-1 V3 loops which are very similar at the protein level despite being distant by cladistic analysis, and which do not possess the distinctive positively charged residues. Highly conserved V3 loop protein sequences are also encountered in SIVAGMs and CIVs (chimpanzee viral strains), which do not appear to be pathogenic in their wild-caught natural hosts.

Diversity analysis in Cannabis sativa based on large-scale development of expressed sequence tag-derived simple sequence repeat markers.

Science.gov (United States)

Gao, Chunsheng; Xin, Pengfei; Cheng, Chaohua; Tang, Qing; Chen, Ping; Wang, Changbiao; Zang, Gonggu; Zhao, Lining

2014-01-01

Cannabis sativa L. is an important economic plant for the production of food, fiber, oils, and intoxicants. However, lack of sufficient simple sequence repeat (SSR) markers has limited the development of cannabis genetic research. Here, large-scale development of expressed sequence tag simple sequence repeat (EST-SSR) markers was performed to obtain more informative genetic markers, and to assess genetic diversity in cannabis (Cannabis sativa L.). Based on the cannabis transcriptome, 4,577 SSRs were identified from 3,624 ESTs. From there, a total of 3,442 complementary primer pairs were designed as SSR markers. Among these markers, trinucleotide repeat motifs (50.99%) were the most abundant, followed by hexanucleotide (25.13%), dinucleotide (16.34%), tetranucloetide (3.8%), and pentanucleotide (3.74%) repeat motifs, respectively. The AAG/CTT trinucleotide repeat (17.96%) was the most abundant motif detected in the SSRs. One hundred and seventeen EST-SSR markers were randomly selected to evaluate primer quality in 24 cannabis varieties. Among these 117 markers, 108 (92.31%) were successfully amplified and 87 (74.36%) were polymorphic. Forty-five polymorphic primer pairs were selected to evaluate genetic diversity and relatedness among the 115 cannabis genotypes. The results showed that 115 varieties could be divided into 4 groups primarily based on geography: Northern China, Europe, Central China, and Southern China. Moreover, the coefficient of similarity when comparing cannabis from Northern China with the European group cannabis was higher than that when comparing with cannabis from the other two groups, owing to a similar climate. This study outlines the first large-scale development of SSR markers for cannabis. These data may serve as a foundation for the development of genetic linkage, quantitative trait loci mapping, and marker-assisted breeding of cannabis.

Winnowing DNA for rare sequences: highly specific sequence and methylation based enrichment.

Directory of Open Access Journals (Sweden)

Jason D Thompson

Full Text Available Rare mutations in cell populations are known to be hallmarks of many diseases and cancers. Similarly, differential DNA methylation patterns arise in rare cell populations with diagnostic potential such as fetal cells circulating in maternal blood. Unfortunately, the frequency of alleles with diagnostic potential, relative to wild-type background sequence, is often well below the frequency of errors in currently available methods for sequence analysis, including very high throughput DNA sequencing. We demonstrate a DNA preparation and purification method that through non-linear electrophoretic separation in media containing oligonucleotide probes, achieves 10,000 fold enrichment of target DNA with single nucleotide specificity, and 100 fold enrichment of unmodified methylated DNA differing from the background by the methylation of a single cytosine residue.

Winnowing DNA for rare sequences: highly specific sequence and methylation based enrichment.

Science.gov (United States)

Thompson, Jason D; Shibahara, Gosuke; Rajan, Sweta; Pel, Joel; Marziali, Andre

2012-01-01

Rare mutations in cell populations are known to be hallmarks of many diseases and cancers. Similarly, differential DNA methylation patterns arise in rare cell populations with diagnostic potential such as fetal cells circulating in maternal blood. Unfortunately, the frequency of alleles with diagnostic potential, relative to wild-type background sequence, is often well below the frequency of errors in currently available methods for sequence analysis, including very high throughput DNA sequencing. We demonstrate a DNA preparation and purification method that through non-linear electrophoretic separation in media containing oligonucleotide probes, achieves 10,000 fold enrichment of target DNA with single nucleotide specificity, and 100 fold enrichment of unmodified methylated DNA differing from the background by the methylation of a single cytosine residue.

Query-dependent banding (QDB for faster RNA similarity searches.

Directory of Open Access Journals (Sweden)

Eric P Nawrocki

2007-03-01

Full Text Available When searching sequence databases for RNAs, it is desirable to score both primary sequence and RNA secondary structure similarity. Covariance models (CMs are probabilistic models well-suited for RNA similarity search applications. However, the computational complexity of CM dynamic programming alignment algorithms has limited their practical application. Here we describe an acceleration method called query-dependent banding (QDB, which uses the probabilistic query CM to precalculate regions of the dynamic programming lattice that have negligible probability, independently of the target database. We have implemented QDB in the freely available Infernal software package. QDB reduces the average case time complexity of CM alignment from LN(2.4 to LN(1.3 for a query RNA of N residues and a target database of L residues, resulting in a 4-fold speedup for typical RNA queries. Combined with other improvements to Infernal, including informative mixture Dirichlet priors on model parameters, benchmarks also show increased sensitivity and specificity resulting from improved parameterization.

A self-similar hierarchy of the Korean stock market

Science.gov (United States)

Lim, Gyuchang; Min, Seungsik; Yoo, Kun-Woo

2013-01-01

A scaling analysis is performed on market values of stocks listed on Korean stock exchanges such as the KOSPI and the KOSDAQ. Different from previous studies on price fluctuations, market capitalizations are dealt with in this work. First, we show that the sum of the two stock exchanges shows a clear rank-size distribution, i.e., the Zipf's law, just as each separate one does. Second, by abstracting Zipf's law as a γ-sequence, we define a self-similar hierarchy consisting of many levels, with the numbers of firms at each level forming a geometric sequence. We also use two exponential functions to describe the hierarchy and derive a scaling law from them. Lastly, we propose a self-similar hierarchical process and perform an empirical analysis on our data set. Based on our findings, we argue that all money invested in the stock market is distributed in a hierarchical way and that a slight difference exists between the two exchanges.

Functional region prediction with a set of appropriate homologous sequences-an index for sequence selection by integrating structure and sequence information with spatial statistics

Science.gov (United States)

2012-01-01

Background The detection of conserved residue clusters on a protein structure is one of the effective strategies for the prediction of functional protein regions. Various methods, such as Evolutionary Trace, have been developed based on this strategy. In such approaches, the conserved residues are identified through comparisons of homologous amino acid sequences. Therefore, the selection of homologous sequences is a critical step. It is empirically known that a certain degree of sequence divergence in the set of homologous sequences is required for the identification of conserved residues. However, the development of a method to select homologous sequences appropriate for the identification of conserved residues has not been sufficiently addressed. An objective and general method to select appropriate homologous sequences is desired for the efficient prediction of functional regions. Results We have developed a novel index to select the sequences appropriate for the identification of conserved residues, and implemented the index within our method to predict the functional regions of a protein. The implementation of the index improved the performance of the functional region prediction. The index represents the degree of conserved residue clustering on the tertiary structure of the protein. For this purpose, the structure and sequence information were integrated within the index by the application of spatial statistics. Spatial statistics is a field of statistics in which not only the attributes but also the geometrical coordinates of the data are considered simultaneously. Higher degrees of clustering generate larger index scores. We adopted the set of homologous sequences with the highest index score, under the assumption that the best prediction accuracy is obtained when the degree of clustering is the maximum. The set of sequences selected by the index led to higher functional region prediction performance than the sets of sequences selected by other sequence

AlignMe—a membrane protein sequence alignment web server

Science.gov (United States)

Stamm, Marcus; Staritzbichler, René; Khafizov, Kamil; Forrest, Lucy R.

2014-01-01

We present a web server for pair-wise alignment of membrane protein sequences, using the program AlignMe. The server makes available two operational modes of AlignMe: (i) sequence to sequence alignment, taking two sequences in fasta format as input, combining information about each sequence from multiple sources and producing a pair-wise alignment (PW mode); and (ii) alignment of two multiple sequence alignments to create family-averaged hydropathy profile alignments (HP mode). For the PW sequence alignment mode, four different optimized parameter sets are provided, each suited to pairs of sequences with a specific similarity level. These settings utilize different types of inputs: (position-specific) substitution matrices, secondary structure predictions and transmembrane propensities from transmembrane predictions or hydrophobicity scales. In the second (HP) mode, each input multiple sequence alignment is converted into a hydrophobicity profile averaged over the provided set of sequence homologs; the two profiles are then aligned. The HP mode enables qualitative comparison of transmembrane topologies (and therefore potentially of 3D folds) of two membrane proteins, which can be useful if the proteins have low sequence similarity. In summary, the AlignMe web server provides user-friendly access to a set of tools for analysis and comparison of membrane protein sequences. Access is available at http://www.bioinfo.mpg.de/AlignMe PMID:24753425

Evolutionary rates at codon sites may be used to align sequences and infer protein domain function

Directory of Open Access Journals (Sweden)

Hazelhurst Scott

2010-03-01

Full Text Available Abstract Background Sequence alignments form part of many investigations in molecular biology, including the determination of phylogenetic relationships, the prediction of protein structure and function, and the measurement of evolutionary rates. However, to obtain meaningful results, a significant degree of sequence similarity is required to ensure that the alignments are accurate and the inferences correct. Limitations arise when sequence similarity is low, which is particularly problematic when working with fast-evolving genes, evolutionary distant taxa, genomes with nucleotide biases, and cases of convergent evolution. Results A novel approach was conceptualized to address the "low sequence similarity" alignment problem. We developed an alignment algorithm termed FIRE (Functional Inference using the Rates of Evolution, which aligns sequences using the evolutionary rate at codon sites, as measured by the dN/dS ratio, rather than nucleotide or amino acid residues. FIRE was used to test the hypotheses that evolutionary rates can be used to align sequences and that the alignments may be used to infer protein domain function. Using a range of test data, we found that aligning domains based on evolutionary rates was possible even when sequence similarity was very low (for example, antibody variable regions. Furthermore, the alignment has the potential to infer protein domain function, indicating that domains with similar functions are subject to similar evolutionary constraints. These data suggest that an evolutionary rate-based approach to sequence analysis (particularly when combined with structural data may be used to study cases of convergent evolution or when sequences have very low similarity. However, when aligning homologous gene sets with sequence similarity, FIRE did not perform as well as the best traditional alignment algorithms indicating that the conventional approach of aligning residues as opposed to evolutionary rates remains the

galaxie--CGI scripts for sequence identification through automated phylogenetic analysis.

Science.gov (United States)

Nilsson, R Henrik; Larsson, Karl-Henrik; Ursing, Björn M

2004-06-12

The prevalent use of similarity searches like BLAST to identify sequences and species implicitly assumes the reference database to be of extensive sequence sampling. This is often not the case, restraining the correctness of the outcome as a basis for sequence identification. Phylogenetic inference outperforms similarity searches in retrieving correct phylogenies and consequently sequence identities, and a project was initiated to design a freely available script package for sequence identification through automated Web-based phylogenetic analysis. Three CGI scripts were designed to facilitate qualified sequence identification from a Web interface. Query sequences are aligned to pre-made alignments or to alignments made by ClustalW with entries retrieved from a BLAST search. The subsequent phylogenetic analysis is based on the PHYLIP package for inferring neighbor-joining and parsimony trees. The scripts are highly configurable. A service installation and a version for local use are found at http://andromeda.botany.gu.se/galaxiewelcome.html and http://galaxie.cgb.ki.se

An accurate and rapid continuous wavelet dynamic time warping algorithm for unbalanced global mapping in nanopore sequencing

KAUST Repository

Han, Renmin

2017-12-24

Long-reads, point-of-care, and PCR-free are the promises brought by nanopore sequencing. Among various steps in nanopore data analysis, the global mapping between the raw electrical current signal sequence and the expected signal sequence from the pore model serves as the key building block to base calling, reads mapping, variant identification, and methylation detection. However, the ultra-long reads of nanopore sequencing and an order of magnitude difference in the sampling speeds of the two sequences make the classical dynamic time warping (DTW) and its variants infeasible to solve the problem. Here, we propose a novel multi-level DTW algorithm, cwDTW, based on continuous wavelet transforms with different scales of the two signal sequences. Our algorithm starts from low-resolution wavelet transforms of the two sequences, such that the transformed sequences are short and have similar sampling rates. Then the peaks and nadirs of the transformed sequences are extracted to form feature sequences with similar lengths, which can be easily mapped by the original DTW. Our algorithm then recursively projects the warping path from a lower-resolution level to a higher-resolution one by building a context-dependent boundary and enabling a constrained search for the warping path in the latter. Comprehensive experiments on two real nanopore datasets on human and on Pandoraea pnomenusa, as well as two benchmark datasets from previous studies, demonstrate the efficiency and effectiveness of the proposed algorithm. In particular, cwDTW can almost always generate warping paths that are very close to the original DTW, which are remarkably more accurate than the state-of-the-art methods including FastDTW and PrunedDTW. Meanwhile, on the real nanopore datasets, cwDTW is about 440 times faster than FastDTW and 3000 times faster than the original DTW. Our program is available at https://github.com/realbigws/cwDTW.

Collaborative Filtering Recommendation on Users' Interest Sequences.

Directory of Open Access Journals (Sweden)

Weijie Cheng

Full Text Available As an important factor for improving recommendations, time information has been introduced to model users' dynamic preferences in many papers. However, the sequence of users' behaviour is rarely studied in recommender systems. Due to the users' unique behavior evolution patterns and personalized interest transitions among items, users' similarity in sequential dimension should be introduced to further distinguish users' preferences and interests. In this paper, we propose a new collaborative filtering recommendation method based on users' interest sequences (IS that rank users' ratings or other online behaviors according to the timestamps when they occurred. This method extracts the semantics hidden in the interest sequences by the length of users' longest common sub-IS (LCSIS and the count of users' total common sub-IS (ACSIS. Then, these semantics are utilized to obtain users' IS-based similarities and, further, to refine the similarities acquired from traditional collaborative filtering approaches. With these updated similarities, transition characteristics and dynamic evolution patterns of users' preferences are considered. Our new proposed method was compared with state-of-the-art time-aware collaborative filtering algorithms on datasets MovieLens, Flixster and Ciao. The experimental results validate that the proposed recommendation method is effective and outperforms several existing algorithms in the accuracy of rating prediction.

Collaborative Filtering Recommendation on Users' Interest Sequences.

Science.gov (United States)

Cheng, Weijie; Yin, Guisheng; Dong, Yuxin; Dong, Hongbin; Zhang, Wansong

2016-01-01

As an important factor for improving recommendations, time information has been introduced to model users' dynamic preferences in many papers. However, the sequence of users' behaviour is rarely studied in recommender systems. Due to the users' unique behavior evolution patterns and personalized interest transitions among items, users' similarity in sequential dimension should be introduced to further distinguish users' preferences and interests. In this paper, we propose a new collaborative filtering recommendation method based on users' interest sequences (IS) that rank users' ratings or other online behaviors according to the timestamps when they occurred. This method extracts the semantics hidden in the interest sequences by the length of users' longest common sub-IS (LCSIS) and the count of users' total common sub-IS (ACSIS). Then, these semantics are utilized to obtain users' IS-based similarities and, further, to refine the similarities acquired from traditional collaborative filtering approaches. With these updated similarities, transition characteristics and dynamic evolution patterns of users' preferences are considered. Our new proposed method was compared with state-of-the-art time-aware collaborative filtering algorithms on datasets MovieLens, Flixster and Ciao. The experimental results validate that the proposed recommendation method is effective and outperforms several existing algorithms in the accuracy of rating prediction.

Collaborative Filtering Recommendation on Users’ Interest Sequences

Science.gov (United States)

Cheng, Weijie; Yin, Guisheng; Dong, Yuxin; Dong, Hongbin; Zhang, Wansong

2016-01-01

As an important factor for improving recommendations, time information has been introduced to model users’ dynamic preferences in many papers. However, the sequence of users’ behaviour is rarely studied in recommender systems. Due to the users’ unique behavior evolution patterns and personalized interest transitions among items, users’ similarity in sequential dimension should be introduced to further distinguish users’ preferences and interests. In this paper, we propose a new collaborative filtering recommendation method based on users’ interest sequences (IS) that rank users’ ratings or other online behaviors according to the timestamps when they occurred. This method extracts the semantics hidden in the interest sequences by the length of users’ longest common sub-IS (LCSIS) and the count of users’ total common sub-IS (ACSIS). Then, these semantics are utilized to obtain users’ IS-based similarities and, further, to refine the similarities acquired from traditional collaborative filtering approaches. With these updated similarities, transition characteristics and dynamic evolution patterns of users’ preferences are considered. Our new proposed method was compared with state-of-the-art time-aware collaborative filtering algorithms on datasets MovieLens, Flixster and Ciao. The experimental results validate that the proposed recommendation method is effective and outperforms several existing algorithms in the accuracy of rating prediction. PMID:27195787

Team-based learning to improve learning outcomes in a therapeutics course sequence.

Science.gov (United States)

Bleske, Barry E; Remington, Tami L; Wells, Trisha D; Dorsch, Michael P; Guthrie, Sally K; Stumpf, Janice L; Alaniz, Marissa C; Ellingrod, Vicki L; Tingen, Jeffrey M

2014-02-12

To compare the effectiveness of team-based learning (TBL) to that of traditional lectures on learning outcomes in a therapeutics course sequence. A revised TBL curriculum was implemented in a therapeutic course sequence. Multiple choice and essay questions identical to those used to test third-year students (P3) taught using a traditional lecture format were administered to the second-year pharmacy students (P2) taught using the new TBL format. One hundred thirty-one multiple-choice questions were evaluated; 79 tested recall of knowledge and 52 tested higher level, application of knowledge. For the recall questions, students taught through traditional lectures scored significantly higher compared to the TBL students (88%±12% vs. 82%±16%, p=0.01). For the questions assessing application of knowledge, no differences were seen between teaching pedagogies (81%±16% vs. 77%±20%, p=0.24). Scores on essay questions and the number of students who achieved 100% were also similar between groups. Transition to a TBL format from a traditional lecture-based pedagogy allowed P2 students to perform at a similar level as students with an additional year of pharmacy education on application of knowledge type questions. However, P3 students outperformed P2 students regarding recall type questions and overall. Further assessment of long-term learning outcomes is needed to determine if TBL produces more persistent learning and improved application in clinical settings.

Similar Representations of Sequence Knowledge in Young and Older Adults: A Study of Effector Independent Transfer

NARCIS (Netherlands)

Barnhoorn, Jonathan Sebastiaan; Döhring, Falko R.; van Asseldonk, Edwin H.F.; Verwey, Willem B.

2016-01-01

Older adults show reduced motor performance and changes in motor skill development. To better understand these changes, we studied differences in sequence knowledge representations between young and older adults using a transfer task. Transfer, or the ability to apply motor skills flexibly, is

Characterization of promoter sequence of toll-like receptor genes in Vechur cattle

Directory of Open Access Journals (Sweden)

R. Lakshmi

2016-06-01

Full Text Available Aim: To analyze the promoter sequence of toll-like receptor (TLR genes in Vechur cattle, an indigenous breed of Kerala with the sequence of Bos taurus and access the differences that could be attributed to innate immune responses against bovine mastitis. Materials and Methods: Blood samples were collected from Jugular vein of Vechur cattle, maintained at Vechur cattle conservation center of Kerala Veterinary and Animal Sciences University, using an acid-citrate-dextrose anticoagulant. The genomic DNA was extracted, and polymerase chain reaction was carried out to amplify the promoter region of TLRs. The amplified product of TLR2, 4, and 9 promoter regions was sequenced by Sanger enzymatic DNA sequencing technique. Results: The sequence of promoter region of TLR2 of Vechur cattle with the B. taurus sequence present in GenBank showed 98% similarity and revealed variants for four sequence motifs. The sequence of the promoter region of TLR4 of Vechur cattle revealed 99% similarity with that of B. taurus sequence but not reveals significant variant in motifregions. However, two heterozygous loci were observed from the chromatogram. Promoter sequence of TLR9 gene also showed 99% similarity to B. taurus sequence and revealed variants for four sequence motifs. Conclusion: The results of this study indicate that significant variation in the promoter of TLR2 and 9 genes in Vechur cattle breed and may potentially link the influence the innate immunity response against mastitis diseases.

Sequence requirement of the ade6-4095 meiotic recombination hotspot in Schizosaccharomyces pombe.

Science.gov (United States)

Foulis, Steven J; Fowler, Kyle R; Steiner, Walter W

2018-02-01

Homologous recombination occurs at a greatly elevated frequency in meiosis compared to mitosis and is initiated by programmed double-strand DNA breaks (DSBs). DSBs do not occur at uniform frequency throughout the genome in most organisms, but occur preferentially at a limited number of sites referred to as hotspots. The location of hotspots have been determined at nucleotide-level resolution in both the budding and fission yeasts, and while several patterns have emerged regarding preferred locations for DSB hotspots, it remains unclear why particular sites experience DSBs at much higher frequency than other sites with seemingly similar properties. Short sequence motifs, which are often sites for binding of transcription factors, are known to be responsible for a number of hotspots. In this study we identified the minimum sequence required for activity of one of such motif identified in a screen of random sequences capable of producing recombination hotspots. The experimentally determined sequence, GGTCTRGACC, closely matches the previously inferred sequence. Full hotspot activity requires an effective sequence length of 9.5 bp, whereas moderate activity requires an effective sequence length of approximately 8.2 bp and shows significant association with DSB hotspots. In combination with our previous work, this result is consistent with a large number of different sequence motifs capable of producing recombination hotspots, and supports a model in which hotspots can be rapidly regenerated by mutation as they are lost through recombination.

Sequence similarity between the cp gene and the transgene in transgenic papayas = Similaridade de seqüência entre o gene cp do vírus e do transgene presente em mamoeiros transgênicos

NARCIS (Netherlands)

Souza, M.T.; Teixeira, M.; Gonsalves, D.

2005-01-01

The Papaya ringspot virus (PRSV) coat protein transgene present in 'Rainbow' and 'SunUp' papayas disclose high sequence similarity (>89%) to the cp gene from PRSV BR and TH. Despite this, both isolates are able to break down the resistance in 'Rainbow', while only the latter is able to do so in

Dynamic programming algorithms for biological sequence comparison.

Science.gov (United States)

Pearson, W R; Miller, W

1992-01-01

Efficient dynamic programming algorithms are available for a broad class of protein and DNA sequence comparison problems. These algorithms require computer time proportional to the product of the lengths of the two sequences being compared [O(N2)] but require memory space proportional only to the sum of these lengths [O(N)]. Although the requirement for O(N2) time limits use of the algorithms to the largest computers when searching protein and DNA sequence databases, many other applications of these algorithms, such as calculation of distances for evolutionary trees and comparison of a new sequence to a library of sequence profiles, are well within the capabilities of desktop computers. In particular, the results of library searches with rapid searching programs, such as FASTA or BLAST, should be confirmed by performing a rigorous optimal alignment. Whereas rapid methods do not overlook significant sequence similarities, FASTA limits the number of gaps that can be inserted into an alignment, so that a rigorous alignment may extend the alignment substantially in some cases. BLAST does not allow gaps in the local regions that it reports; a calculation that allows gaps is very likely to extend the alignment substantially. Although a Monte Carlo evaluation of the statistical significance of a similarity score with a rigorous algorithm is much slower than the heuristic approach used by the RDF2 program, the dynamic programming approach should take less than 1 hr on a 386-based PC or desktop Unix workstation. For descriptive purposes, we have limited our discussion to methods for calculating similarity scores and distances that use gap penalties of the form g = rk. Nevertheless, programs for the more general case (g = q+rk) are readily available. Versions of these programs that run either on Unix workstations, IBM-PC class computers, or the Macintosh can be obtained from either of the authors.

Highly conserved non-coding sequences are associated with vertebrate development.

Directory of Open Access Journals (Sweden)

Adam Woolfe

2005-01-01

Full Text Available In addition to protein coding sequence, the human genome contains a significant amount of regulatory DNA, the identification of which is proving somewhat recalcitrant to both in silico and functional methods. An approach that has been used with some success is comparative sequence analysis, whereby equivalent genomic regions from different organisms are compared in order to identify both similarities and differences. In general, similarities in sequence between highly divergent organisms imply functional constraint. We have used a whole-genome comparison between humans and the pufferfish, Fugu rubripes, to identify nearly 1,400 highly conserved non-coding sequences. Given the evolutionary divergence between these species, it is likely that these sequences are found in, and furthermore are essential to, all vertebrates. Most, and possibly all, of these sequences are located in and around genes that act as developmental regulators. Some of these sequences are over 90% identical across more than 500 bases, being more highly conserved than coding sequence between these two species. Despite this, we cannot find any similar sequences in invertebrate genomes. In order to begin to functionally test this set of sequences, we have used a rapid in vivo assay system using zebrafish embryos that allows tissue-specific enhancer activity to be identified. Functional data is presented for highly conserved non-coding sequences associated with four unrelated developmental regulators (SOX21, PAX6, HLXB9, and SHH, in order to demonstrate the suitability of this screen to a wide range of genes and expression patterns. Of 25 sequence elements tested around these four genes, 23 show significant enhancer activity in one or more tissues. We have identified a set of non-coding sequences that are highly conserved throughout vertebrates. They are found in clusters across the human genome, principally around genes that are implicated in the regulation of development

[Complete genome sequencing and analyses of rabies viruses isolated from wild animals (Chinese Ferret-Badger) in Zhejiang province].

Science.gov (United States)

Lei, Yong-Liang; Wang, Xiao-Guang; Liu, Fu-Ming; Chen, Xiu-Ying; Ye, Bi-Feng; Mei, Jian-Hua; Lan, Jin-Quan; Tang, Qing

2009-08-01

Based on sequencing the full-length genomes of two Chinese Ferret-Badger, we analyzed the properties of rabies viruses genetic variation in molecular level to get information on prevalence and variation of rabies viruses in Zhejiang, and to enrich the genome database of rabies viruses street strains isolated from Chinese wildlife. Overlapped fragments were amplified by RT-PCR and full-length genomes were assembled to analyze the nucleotide and deduced protein similarities and phylogenetic analyses of the N genes from Chinese Ferret-Badger, sika deer, vole, dog. Vaccine strains were then determined. The two full-length genomes were completely sequenced to find out that they had the same genetic structure with 11 923 nts including 58 nts-Leader, 1353 nts-NP, 894 nts-PP, 609 nts-MP, 1575 nts-GP, 6386 nts-LP, and 2, 5, 5 nts- intergenic regions (IGRs), 423 nts-Pseudogene-like sequence (Psi), 70 nts-Trailer. The two full-length genomes were in accordance with the properties of Rhabdoviridae Lyssa virus by blast and multi-sequence alignment. The nucleotide and amino acid sequences among Chinese strains had the highest similarity, especially among animals of the same species. Of the two full-length genomes, the similarity in amino acid level was dramatically higher than that in nucleotide level, so that the nucleotide mutations happened in these two genomes were most probably as synonymous mutations. Compared to the referenced rabies viruses, the lengths of the five protein coding regions did not show any changes or recombination, but only with a few-point mutations. It was evident that the five proteins appeared to be stable. The variation sites and types of the two ferret badgers genomes were similar to the referenced vaccine or street strains. The two strains were genotype 1 according to the multi-sequence and phylogenetic analyses, which possessing the distinct geographyphic characteristics of China. All the evidence suggested a cue that these two ferret badgers

Protein Function Prediction Based on Sequence and Structure Information

KAUST Repository

Smaili, Fatima Z.

2016-05-25

The number of available protein sequences in public databases is increasing exponentially. However, a significant fraction of these sequences lack functional annotation which is essential to our understanding of how biological systems and processes operate. In this master thesis project, we worked on inferring protein functions based on the primary protein sequence. In the approach we follow, 3D models are first constructed using I-TASSER. Functions are then deduced by structurally matching these predicted models, using global and local similarities, through three independent enzyme commission (EC) and gene ontology (GO) function libraries. The method was tested on 250 “hard” proteins, which lack homologous templates in both structure and function libraries. The results show that this method outperforms the conventional prediction methods based on sequence similarity or threading. Additionally, our method could be improved even further by incorporating protein-protein interaction information. Overall, the method we use provides an efficient approach for automated functional annotation of non-homologous proteins, starting from their sequence.

Searching the protein structure database for ligand-binding site similarities using CPASS v.2

Directory of Open Access Journals (Sweden)

Caprez Adam

2011-01-01

Full Text Available Abstract Background A recent analysis of protein sequences deposited in the NCBI RefSeq database indicates that ~8.5 million protein sequences are encoded in prokaryotic and eukaryotic genomes, where ~30% are explicitly annotated as "hypothetical" or "uncharacterized" protein. Our Comparison of Protein Active-Site Structures (CPASS v.2 database and software compares the sequence and structural characteristics of experimentally determined ligand binding sites to infer a functional relationship in the absence of global sequence or structure similarity. CPASS is an important component of our Functional Annotation Screening Technology by NMR (FAST-NMR protocol and has been successfully applied to aid the annotation of a number of proteins of unknown function. Findings We report a major upgrade to our CPASS software and database that significantly improves its broad utility. CPASS v.2 is designed with a layered architecture to increase flexibility and portability that also enables job distribution over the Open Science Grid (OSG to increase speed. Similarly, the CPASS interface was enhanced to provide more user flexibility in submitting a CPASS query. CPASS v.2 now allows for both automatic and manual definition of ligand-binding sites and permits pair-wise, one versus all, one versus list, or list versus list comparisons. Solvent accessible surface area, ligand root-mean square difference, and Cβ distances have been incorporated into the CPASS similarity function to improve the quality of the results. The CPASS database has also been updated. Conclusions CPASS v.2 is more than an order of magnitude faster than the original implementation, and allows for multiple simultaneous job submissions. Similarly, the CPASS database of ligand-defined binding sites has increased in size by ~ 38%, dramatically increasing the likelihood of a positive search result. The modification to the CPASS similarity function is effective in reducing CPASS similarity scores

The relationships within the mathematical content of teachers’ lesson sequences

Science.gov (United States)

Shahrill, M.; Prahmana, R. C. I.; Roslan, R.

2017-12-01

This study explored how mathematics content is carried through by means of the problems presented during lessons. Following the definitions and the coding criteria from the TIMSS 1999 Video Study, a total of 163 mathematics problems were identified in the video- recorded lesson sequences of four Bruneian mathematics teachers teaching at the Year 8 level. These problems were classified according to the four basic kinds of relationships: mathematically related, thematically related, repetition and unrelated. Drawing on the mathematical content of the teachers’ lesson sequences, the findings revealed variations among the mathematical problems coded as repetition and thematically related, between the four Brunei classes. The aggregated results obtained from the four classes highlighted several points of discussion, such as the relatively higher proportion of repetition problems (52%) from one teacher in particular; the percentage similarities of thematically related problems for all four classes (ranging from 26% to 33%); and the incredibly varied results for mathematically related problems across the four Brunei classes.

Revisiting Inter-Genre Similarity

DEFF Research Database (Denmark)

Sturm, Bob L.; Gouyon, Fabien

2013-01-01

We revisit the idea of ``inter-genre similarity'' (IGS) for machine learning in general, and music genre recognition in particular. We show analytically that the probability of error for IGS is higher than naive Bayes classification with zero-one loss (NB). We show empirically that IGS does...... not perform well, even for data that satisfies all its assumptions....

Information filtering based on transferring similarity.

Science.gov (United States)

Sun, Duo; Zhou, Tao; Liu, Jian-Guo; Liu, Run-Ran; Jia, Chun-Xiao; Wang, Bing-Hong

2009-07-01

In this Brief Report, we propose an index of user similarity, namely, the transferring similarity, which involves all high-order similarities between users. Accordingly, we design a modified collaborative filtering algorithm, which provides remarkably higher accurate predictions than the standard collaborative filtering. More interestingly, we find that the algorithmic performance will approach its optimal value when the parameter, contained in the definition of transferring similarity, gets close to its critical value, before which the series expansion of transferring similarity is convergent and after which it is divergent. Our study is complementary to the one reported in [E. A. Leicht, P. Holme, and M. E. J. Newman, Phys. Rev. E 73, 026120 (2006)], and is relevant to the missing link prediction problem.

Sequence analysis of Leukemia DNA

Science.gov (United States)

Nacong, Nasria; Lusiyanti, Desy; Irawan, Muhammad. Isa

2018-03-01

Cancer is a very deadly disease, one of which is leukemia disease or better known as blood cancer. The cancer cell can be detected by taking DNA in laboratory test. This study focused on local alignment of leukemia and non leukemia data resulting from NCBI in the form of DNA sequences by using Smith-Waterman algorithm. SmithWaterman algorithm was invented by TF Smith and MS Waterman in 1981. These algorithms try to find as much as possible similarity of a pair of sequences, by giving a negative value to the unequal base pair (mismatch), and positive values on the same base pair (match). So that will obtain the maximum positive value as the end of the alignment, and the minimum value as the initial alignment. This study will use sequences of leukemia and 3 sequences of non leukemia.

Cloning and sequence analysis of sucrose phosphate synthase gene from varieties of Pennisetum species.

Science.gov (United States)

Li, H C; Lu, H B; Yang, F Y; Liu, S J; Bai, C J; Zhang, Y W

2015-03-31

Sucrose phosphate synthase (SPS) is an enzyme used by higher plants for sucrose synthesis. In this study, three primer sets were designed on the basis of known SPS sequences from maize (GenBank: NM_001112224.1) and sugarcane (GenBank: JN584485.1), and five novel SPS genes were identified by RT-PCR from the genomes of Pennisetum spp (the hybrid P. americanum x P. purpureum, P. purpureum Schum., P. purpureum Schum. cv. Red, P. purpureum Schum. cv. Taiwan, and P. purpureum Schum. cv. Mott). The cloned sequences showed 99.9% identity and 80-88% similarity to the SPS sequences of other plants. The SPS gene of hybrid Pennisetum had one nucleotide and four amino acid polymorphisms compared to the other four germplasms, and cluster analysis was performed to assess genetic diversity in this species. Additional characterization of the SPS gene product can potentially allow Pennisetum to be exploited as a biofuel source.

Comparative analysis of sequences from PT 2013

DEFF Research Database (Denmark)

Mikkelsen, Susie Sommer

Sheatfish and not EHNV. Generally, mistakes occurred at the ends of the sequences. This can be due to several factors. One is that the sequence has not been trimmed of the sequence primer sites. Another is the lack of quality control of the chromatogram. Finally, sequencing in just one direction can result...... diseases in Europe. As part of the EURL proficiency test for fish diseases it is required to sequence any RANA virus isolates found in any of the samples. It is also highly recommended to sequence the ISA virus to determine whether it be HPRΔ or HPR0. Furthermore, it is recommended that any VHSV and IHNV...... isolates be genotyped. As part of the evaluation of the proficiency results it was decided this year to look into the quality and similarity of the sequence results for selected viruses. Ampoule III in the proficiency test 2013 contained an EHNV isolate. The EURL received 43 sequences from 41 laboratories...

Mass extrapolation of quarks and leptons to higher generations

Energy Technology Data Exchange (ETDEWEB)

Barik, N [Utkal Univ., Bhubaneswar (India). Dept. of Physics

1981-05-01

An empirical mass formula is tested for the basic fermion sequences of charged quarks and leptons. This relation is a generalization of Barut's mass formula for the lepton sequence (e, ..mu.., tau ....). It is found that successful mass extrapolation to the third and possibly to other higher generations (N > 2) can be obtained with the first and second generation masses as inputs, which predicts the top quark mass msub(t) to be around 20 GeV. This also leads to the mass ratios between members of two different sequences (i) and (i') corresponding to the same higher generations (N > 2).

Mass extrapolation of quarks and leptons to higher generations

International Nuclear Information System (INIS)

Barik, N.

1981-01-01

An empirical mass formula is tested for the basic fermion sequences of charged quarks and leptons. This relation is a generalization of Barut's mass formula for the lepton sequence (e, μ, tau ....). It is found that successful mass extrapolation to the third and possibly to other higher generations (N > 2) can be obtained with the first and second generation masses as inputs, which predicts the top quark mass msub(t) to be around 20 GeV. This also leads to the mass ratios between members of two different sequences (i) and (i') corresponding to the same higher generations (N > 2). (author)

[Sequencing and analysis of complete genome of rabies viruses isolated from Chinese Ferret-Badger and dog in Zhejiang province].

Science.gov (United States)

Lei, Yong-Liang; Wang, Xiao-Guang; Tao, Xiao-Yan; Li, Hao; Meng, Sheng-Li; Chen, Xiu-Ying; Liu, Fu-Ming; Ye, Bi-Feng; Tang, Qing

2010-01-01

Based on sequencing the full-length genomes of four Chinese Ferret-Badger and dog, we analyze the properties of rabies viruses genetic variation in molecular level, get the information about rabies viruses prevalence and variation in Zhejiang, and enrich the genome database of rabies viruses street strains isolated from China. Rabies viruses in suckling mice were isolated, overlapped fragments were amplified by RT-PCR and full-length genomes were assembled to analyze the nucleotide and deduced protein similarities and phylogenetic analyses from Chinese Ferret-Badger, dog, sika deer, vole, used vaccine strain were determined. The four full-length genomes were sequenced completely and had the same genetic structure with the length of 11, 923 nts or 11, 925 nts including 58 nts-Leader, 1353 nts-NP, 894 nts-PP, 609 nts-MP, 1575 nts-GP, 6386 nts-LP, and 2, 5, 5 nts- intergenic regions(IGRs), 423 nts-Pseudogene-like sequence (psi), 70 nts-Trailer. The four full-length genomes were in accordance with the properties of Rhabdoviridae Lyssa virus by BLAST and multi-sequence alignment. The nucleotide and amino acid sequences among Chinese strains had the highest similarity, especially among animals of the same species. Of the four full-length genomes, the similarity in amino acid level was dramatically higher than that in nucleotide level, so the nucleotide mutations happened in these four genomes were most synonymous mutations. Compared with the reference rabies viruses, the lengths of the five protein coding regions had no change, no recombination, only with a few point mutations. It was evident that the five proteins appeared to be stable. The variation sites and types of the four genomes were similar to the reference vaccine or street strains. And the four strains were genotype 1 according to the multi-sequence and phylogenetic analyses, which possessed the distinct district characteristics of China. Therefore, these four rabies viruses are likely to be street viruses

Sirius PSB: a generic system for analysis of biological sequences.

Science.gov (United States)

Koh, Chuan Hock; Lin, Sharene; Jedd, Gregory; Wong, Limsoon

2009-12-01

Computational tools are essential components of modern biological research. For example, BLAST searches can be used to identify related proteins based on sequence homology, or when a new genome is sequenced, prediction models can be used to annotate functional sites such as transcription start sites, translation initiation sites and polyadenylation sites and to predict protein localization. Here we present Sirius Prediction Systems Builder (PSB), a new computational tool for sequence analysis, classification and searching. Sirius PSB has four main operations: (1) Building a classifier, (2) Deploying a classifier, (3) Search for proteins similar to query proteins, (4) Preliminary and post-prediction analysis. Sirius PSB supports all these operations via a simple and interactive graphical user interface. Besides being a convenient tool, Sirius PSB has also introduced two novelties in sequence analysis. Firstly, genetic algorithm is used to identify interesting features in the feature space. Secondly, instead of the conventional method of searching for similar proteins via sequence similarity, we introduced searching via features' similarity. To demonstrate the capabilities of Sirius PSB, we have built two prediction models - one for the recognition of Arabidopsis polyadenylation sites and another for the subcellular localization of proteins. Both systems are competitive against current state-of-the-art models based on evaluation of public datasets. More notably, the time and effort required to build each model is greatly reduced with the assistance of Sirius PSB. Furthermore, we show that under certain conditions when BLAST is unable to find related proteins, Sirius PSB can identify functionally related proteins based on their biophysical similarities. Sirius PSB and its related supplements are available at: http://compbio.ddns.comp.nus.edu.sg/~sirius.

SS-Wrapper: a package of wrapper applications for similarity searches on Linux clusters

Directory of Open Access Journals (Sweden)

Lefkowitz Elliot J

2004-10-01

Full Text Available Abstract Background Large-scale sequence comparison is a powerful tool for biological inference in modern molecular biology. Comparing new sequences to those in annotated databases is a useful source of functional and structural information about these sequences. Using software such as the basic local alignment search tool (BLAST or HMMPFAM to identify statistically significant matches between newly sequenced segments of genetic material and those in databases is an important task for most molecular biologists. Searching algorithms are intrinsically slow and data-intensive, especially in light of the rapid growth of biological sequence databases due to the emergence of high throughput DNA sequencing techniques. Thus, traditional bioinformatics tools are impractical on PCs and even on dedicated UNIX servers. To take advantage of larger databases and more reliable methods, high performance computation becomes necessary. Results We describe the implementation of SS-Wrapper (Similarity Search Wrapper, a package of wrapper applications that can parallelize similarity search applications on a Linux cluster. Our wrapper utilizes a query segmentation-search (QS-search approach to parallelize sequence database search applications. It takes into consideration load balancing between each node on the cluster to maximize resource usage. QS-search is designed to wrap many different search tools, such as BLAST and HMMPFAM using the same interface. This implementation does not alter the original program, so newly obtained programs and program updates should be accommodated easily. Benchmark experiments using QS-search to optimize BLAST and HMMPFAM showed that QS-search accelerated the performance of these programs almost linearly in proportion to the number of CPUs used. We have also implemented a wrapper that utilizes a database segmentation approach (DS-BLAST that provides a complementary solution for BLAST searches when the database is too large to fit into

SS-Wrapper: a package of wrapper applications for similarity searches on Linux clusters.

Science.gov (United States)

Wang, Chunlin; Lefkowitz, Elliot J

2004-10-28

Large-scale sequence comparison is a powerful tool for biological inference in modern molecular biology. Comparing new sequences to those in annotated databases is a useful source of functional and structural information about these sequences. Using software such as the basic local alignment search tool (BLAST) or HMMPFAM to identify statistically significant matches between newly sequenced segments of genetic material and those in databases is an important task for most molecular biologists. Searching algorithms are intrinsically slow and data-intensive, especially in light of the rapid growth of biological sequence databases due to the emergence of high throughput DNA sequencing techniques. Thus, traditional bioinformatics tools are impractical on PCs and even on dedicated UNIX servers. To take advantage of larger databases and more reliable methods, high performance computation becomes necessary. We describe the implementation of SS-Wrapper (Similarity Search Wrapper), a package of wrapper applications that can parallelize similarity search applications on a Linux cluster. Our wrapper utilizes a query segmentation-search (QS-search) approach to parallelize sequence database search applications. It takes into consideration load balancing between each node on the cluster to maximize resource usage. QS-search is designed to wrap many different search tools, such as BLAST and HMMPFAM using the same interface. This implementation does not alter the original program, so newly obtained programs and program updates should be accommodated easily. Benchmark experiments using QS-search to optimize BLAST and HMMPFAM showed that QS-search accelerated the performance of these programs almost linearly in proportion to the number of CPUs used. We have also implemented a wrapper that utilizes a database segmentation approach (DS-BLAST) that provides a complementary solution for BLAST searches when the database is too large to fit into the memory of a single node. Used together

Intrinsic atopic dermatitis shows similar TH2 and higher TH17 immune activation compared with extrinsic atopic dermatitis.

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Suárez-Fariñas, Mayte; Dhingra, Nikhil; Gittler, Julia; Shemer, Avner; Cardinale, Irma; de Guzman Strong, Cristina; Krueger, James G; Guttman-Yassky, Emma

2013-08-01

Atopic dermatitis (AD) is classified as extrinsic and intrinsic, representing approximately 80% and 20% of patients with the disease, respectively. Although sharing a similar clinical phenotype, only extrinsic AD is characterized by high serum IgE levels. Because most patients with AD exhibit high IgE levels, an "allergic"/IgE-mediated disease pathogenesis was hypothesized. However, current models associate AD with T-cell activation, particularly TH2/TH22 polarization, and epidermal barrier defects. We sought to define whether both variants share a common pathogenesis. We stratified 51 patients with severe AD into extrinsic AD (n = 42) and intrinsic AD (n = 9) groups (with similar mean disease activity/SCORAD scores) and analyzed the molecular and cellular skin pathology of lesional and nonlesional intrinsic AD and extrinsic AD by using gene expression (real-time PCR) and immunohistochemistry. A significant correlation between IgE levels and SCORAD scores (r = 0.76, P extrinsic AD. Marked infiltrates of T cells and dendritic cells and corresponding epidermal alterations (keratin 16, Mki67, and S100A7/A8/A9) defined lesional skin of patients with both variants. However, higher activation of all inflammatory axes (including TH2) was detected in patients with intrinsic AD, particularly TH17 and TH22 cytokines. Positive correlations between TH17-related molecules and SCORAD scores were only found in patients with intrinsic AD, whereas only patients with extrinsic AD showed positive correlations between SCORAD scores and TH2 cytokine (IL-4 and IL-5) levels and negative correlations with differentiation products (loricrin and periplakin). Although differences in TH17 and TH22 activation exist between patients with intrinsic AD and those with extrinsic AD, we identified common disease-defining features of T-cell activation, production of polarized cytokines, and keratinocyte responses to immune products. Our data indicate that a TH2 bias is not the sole cause of high Ig

Comparison of MRI pulse sequences for investigation of lesions of the cervical spinal cord

International Nuclear Information System (INIS)

Campi, A.; Pontesilli, S.; Gerevini, S.; Scotti, G.

2000-01-01

Small spinal cord lesions, even if clinically significant, can be due to the low sensitivity of some pulse sequences. We compared T2-weighted fast (FSE), and conventional (CSE) spin-echo and short-tau inversion-recovery (STIR)-FSE overlooked on MRI sequences to evaluate their sensitivity to and specificity for lesions of different types. We compared the three sequences in MRI of 57 patients with cervical spinal symptoms. The image sets were assessed by two of us individually for final diagnosis, lesion detectability and image quality. Both readers arrived at the same final diagnoses with all sequences, differentiating four groups of patients. Group 1 (30 patients, 53 %), with a final diagnosis of multiple sclerosis (MS). Demyelinating lesions were better seen on STIR-FSE images, on which the number of lesions was significantly higher than on FSE, while the FSE and CSE images showed approximately equal numbers of lesions; additional lesions were found in 9 patients. The contrast-to-noise ratio (CNR) of 17 demyelinating lesions was significantly higher on STIR-FSE images than with the other sequences. Group 2, 19 patients (33 %) with cervical pain, 15 of whom had disc protrusion or herniation: herniated discs were equally well delineated with all sequences, with better myelographic effect on FSE. In five patients with intrinsic spinal cord abnormalities, the conspicuity and demarcation of the lesions were similar with STIR-FSE and FSE. Group 3, 4 patients (7 %) with acute myelopathy of unknown aetiology. In two patients, STIR-FSE gave better demarcation of lesions and in one a questionable additional lesions. Group 4, 4 patients (7 %) with miscellaneous final diagnoses. STIR-FSE had high sensitivity to demyelinating lesions, can be considered quite specific and should be included in spinal MRI for assessment of suspected demyelinating disease. (orig.)

Sequence determinants of human microsatellite variability

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Jakobsson Mattias

2009-12-01

Full Text Available Abstract Background Microsatellite loci are frequently used in genomic studies of DNA sequence repeats and in population studies of genetic variability. To investigate the effect of sequence properties of microsatellites on their level of variability we have analyzed genotypes at 627 microsatellite loci in 1,048 worldwide individuals from the HGDP-CEPH cell line panel together with the DNA sequences of these microsatellites in the human RefSeq database. Results Calibrating PCR fragment lengths in individual genotypes by using the RefSeq sequence enabled us to infer repeat number in the HGDP-CEPH dataset and to calculate the mean number of repeats (as opposed to the mean PCR fragment length, under the assumption that differences in PCR fragment length reflect differences in the numbers of repeats in the embedded repeat sequences. We find the mean and maximum numbers of repeats across individuals to be positively correlated with heterozygosity. The size and composition of the repeat unit of a microsatellite are also important factors in predicting heterozygosity, with tetra-nucleotide repeat units high in G/C content leading to higher heterozygosity. Finally, we find that microsatellites containing more separate sets of repeated motifs generally have higher heterozygosity. Conclusions These results suggest that sequence properties of microsatellites have a significant impact in determining the features of human microsatellite variability.

GuiTope: an application for mapping random-sequence peptides to protein sequences.

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Halperin, Rebecca F; Stafford, Phillip; Emery, Jack S; Navalkar, Krupa Arun; Johnston, Stephen Albert

2012-01-03

Random-sequence peptide libraries are a commonly used tool to identify novel ligands for binding antibodies, other proteins, and small molecules. It is often of interest to compare the selected peptide sequences to the natural protein binding partners to infer the exact binding site or the importance of particular residues. The ability to search a set of sequences for similarity to a set of peptides may sometimes enable the prediction of an antibody epitope or a novel binding partner. We have developed a software application designed specifically for this task. GuiTope provides a graphical user interface for aligning peptide sequences to protein sequences. All alignment parameters are accessible to the user including the ability to specify the amino acid frequency in the peptide library; these frequencies often differ significantly from those assumed by popular alignment programs. It also includes a novel feature to align di-peptide inversions, which we have found improves the accuracy of antibody epitope prediction from peptide microarray data and shows utility in analyzing phage display datasets. Finally, GuiTope can randomly select peptides from a given library to estimate a null distribution of scores and calculate statistical significance. GuiTope provides a convenient method for comparing selected peptide sequences to protein sequences, including flexible alignment parameters, novel alignment features, ability to search a database, and statistical significance of results. The software is available as an executable (for PC) at http://www.immunosignature.com/software and ongoing updates and source code will be available at sourceforge.net.

GuiTope: an application for mapping random-sequence peptides to protein sequences

Directory of Open Access Journals (Sweden)

Halperin Rebecca F

2012-01-01

Full Text Available Abstract Background Random-sequence peptide libraries are a commonly used tool to identify novel ligands for binding antibodies, other proteins, and small molecules. It is often of interest to compare the selected peptide sequences to the natural protein binding partners to infer the exact binding site or the importance of particular residues. The ability to search a set of sequences for similarity to a set of peptides may sometimes enable the prediction of an antibody epitope or a novel binding partner. We have developed a software application designed specifically for this task. Results GuiTope provides a graphical user interface for aligning peptide sequences to protein sequences. All alignment parameters are accessible to the user including the ability to specify the amino acid frequency in the peptide library; these frequencies often differ significantly from those assumed by popular alignment programs. It also includes a novel feature to align di-peptide inversions, which we have found improves the accuracy of antibody epitope prediction from peptide microarray data and shows utility in analyzing phage display datasets. Finally, GuiTope can randomly select peptides from a given library to estimate a null distribution of scores and calculate statistical significance. Conclusions GuiTope provides a convenient method for comparing selected peptide sequences to protein sequences, including flexible alignment parameters, novel alignment features, ability to search a database, and statistical significance of results. The software is available as an executable (for PC at http://www.immunosignature.com/software and ongoing updates and source code will be available at sourceforge.net.

FASH: A web application for nucleotides sequence search

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Chew Paul

2008-05-01

Full Text Available Abstract FASH (Fourier Alignment Sequence Heuristics is a web application, based on the Fast Fourier Transform, for finding remote homologs within a long nucleic acid sequence. Given a query sequence and a long text-sequence (e.g, the human genome, FASH detects subsequences within the text that are remotely-similar to the query. FASH offers an alternative approach to Blast/Fasta for querying long RNA/DNA sequences. FASH differs from these other approaches in that it does not depend on the existence of contiguous seed-sequences in its initial detection phase. The FASH web server is user friendly and very easy to operate. Availability FASH can be accessed at https://fash.bgu.ac.il:8443/fash/default.jsp (secured website

Large margin classification with indefinite similarities

KAUST Repository

Alabdulmohsin, Ibrahim

2016-01-07

Classification with indefinite similarities has attracted attention in the machine learning community. This is partly due to the fact that many similarity functions that arise in practice are not symmetric positive semidefinite, i.e. the Mercer condition is not satisfied, or the Mercer condition is difficult to verify. Examples of such indefinite similarities in machine learning applications are ample including, for instance, the BLAST similarity score between protein sequences, human-judged similarities between concepts and words, and the tangent distance or the shape matching distance in computer vision. Nevertheless, previous works on classification with indefinite similarities are not fully satisfactory. They have either introduced sources of inconsistency in handling past and future examples using kernel approximation, settled for local-minimum solutions using non-convex optimization, or produced non-sparse solutions by learning in Krein spaces. Despite the large volume of research devoted to this subject lately, we demonstrate in this paper how an old idea, namely the 1-norm support vector machine (SVM) proposed more than 15 years ago, has several advantages over more recent work. In particular, the 1-norm SVM method is conceptually simpler, which makes it easier to implement and maintain. It is competitive, if not superior to, all other methods in terms of predictive accuracy. Moreover, it produces solutions that are often sparser than more recent methods by several orders of magnitude. In addition, we provide various theoretical justifications by relating 1-norm SVM to well-established learning algorithms such as neural networks, SVM, and nearest neighbor classifiers. Finally, we conduct a thorough experimental evaluation, which reveals that the evidence in favor of 1-norm SVM is statistically significant.

Accurate Local-Ancestry Inference in Exome-Sequenced Admixed Individuals via Off-Target Sequence Reads

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Hu, Youna; Willer, Cristen; Zhan, Xiaowei; Kang, Hyun Min; Abecasis, Gonçalo R.

2013-01-01

Estimates of the ancestry of specific chromosomal regions in admixed individuals are useful for studies of human evolutionary history and for genetic association studies. Previously, this ancestry inference relied on high-quality genotypes from genome-wide association study (GWAS) arrays. These high-quality genotypes are not always available when samples are exome sequenced, and exome sequencing is the strategy of choice for many ongoing genetic studies. Here we show that off-target reads generated during exome-sequencing experiments can be combined with on-target reads to accurately estimate the ancestry of each chromosomal segment in an admixed individual. To reconstruct local ancestry, our method SEQMIX models aligned bases directly instead of relying on hard genotype calls. We evaluate the accuracy of our method through simulations and analysis of samples sequenced by the 1000 Genomes Project and the NHLBI Grand Opportunity Exome Sequencing Project. In African Americans, we show that local-ancestry estimates derived by our method are very similar to those derived with Illumina’s Omni 2.5M genotyping array and much improved in relation to estimates that use only exome genotypes and ignore off-target sequencing reads. Software implementing this method, SEQMIX, can be applied to analysis of human population history or used for genetic association studies in admixed individuals. PMID:24210252

Sequence periodicity in nucleosomal DNA and intrinsic curvature.

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Nair, T Murlidharan

2010-05-17

Most eukaryotic DNA contained in the nucleus is packaged by wrapping DNA around histone octamers. Histones are ubiquitous and bind most regions of chromosomal DNA. In order to achieve smooth wrapping of the DNA around the histone octamer, the DNA duplex should be able to deform and should possess intrinsic curvature. The deformability of DNA is a result of the non-parallelness of base pair stacks. The stacking interaction between base pairs is sequence dependent. The higher the stacking energy the more rigid the DNA helix, thus it is natural to expect that sequences that are involved in wrapping around the histone octamer should be unstacked and possess intrinsic curvature. Intrinsic curvature has been shown to be dictated by the periodic recurrence of certain dinucleotides. Several genome-wide studies directed towards mapping of nucleosome positions have revealed periodicity associated with certain stretches of sequences. In the current study, these sequences have been analyzed with a view to understand their sequence-dependent structures. Higher order DNA structures and the distribution of molecular bend loci associated with 146 base nucleosome core DNA sequence from C. elegans and chicken have been analyzed using the theoretical model for DNA curvature. The curvature dispersion calculated by cyclically permuting the sequences revealed that the molecular bend loci were delocalized throughout the nucleosome core region and had varying degrees of intrinsic curvature. The higher order structures associated with nucleosomes of C.elegans and chicken calculated from the sequences revealed heterogeneity with respect to the deviation of the DNA axis. The results points to the possibility of context dependent curvature of varying degrees to be associated with nucleosomal DNA.

Self-similar solutions for implosion and reflection of coalesced shocks in a plasma : spherical and cylindrical geometries

International Nuclear Information System (INIS)

Chavda, L.K.

1978-01-01

Approximate analytic solutions to the self-similar equations of gas dynamics for a plasma, treated as an ideal gas with specific heat ratio γ=5/3 are obtained for the implosion and subsequent reflection of various types of shock sequences in spherical and cylindrical geometries. This is based on the lowest-order polynomial approximation in the reduced fluid velocity, for a suitable nonlinear function of the sound velocity and the fluid velocity. However, the method developed here is powerful enough to be extended analytically to higher order polynomial approximations, to obtain successive approximations to the exact self-similar solutions. Also obtained, for the first time, are exact asymptotic solutions, in analytic form, for the reflected shocks. Criteria are given that may enable one to make a choice between the two geometries for maximising compression or temperature of the gas. These solutions should be useful in the study of inertial confinement of a plasma. (author)

Nucleotide sequence of the human N-myc gene

International Nuclear Information System (INIS)

Stanton, L.W.; Schwab, M.; Bishop, J.M.

1986-01-01

Human neuroblastomas frequently display amplification and augmented expression of a gene known as N-myc because of its similarity to the protooncogene c-myc. It has therefore been proposed that N-myc is itself a protooncogene, and subsequent tests have shown that N-myc and c-myc have similar biological activities in cell culture. The authors have now detailed the kinship between N-myc and c-myc by determining the nucleotide sequence of human N-myc and deducing the amino acid sequence of the protein encoded by the gene. The topography of N-myc is strikingly similar to that of c-myc: both genes contain three exons of similar lengths; the coding elements of both genes are located in the second and third exons; and both genes have unusually long 5' untranslated regions in their mRNAs, with features that raise the possibility that expression of the genes may be subject to similar controls of translation. The resemblance between the proteins encoded by N-myc and c-myc sustains previous suspicions that the genes encode related functions

Improvement of training set structure in fusion data cleaning using Time-Domain Global Similarity method

International Nuclear Information System (INIS)

Liu, J.; Lan, T.; Qin, H.

2017-01-01

Traditional data cleaning identifies dirty data by classifying original data sequences, which is a class-imbalanced problem since the proportion of incorrect data is much less than the proportion of correct ones for most diagnostic systems in Magnetic Confinement Fusion (MCF) devices. When using machine learning algorithms to classify diagnostic data based on class-imbalanced training set, most classifiers are biased towards the major class and show very poor classification rates on the minor class. By transforming the direct classification problem about original data sequences into a classification problem about the physical similarity between data sequences, the class-balanced effect of Time-Domain Global Similarity (TDGS) method on training set structure is investigated in this paper. Meanwhile, the impact of improved training set structure on data cleaning performance of TDGS method is demonstrated with an application example in EAST POlarimetry-INTerferometry (POINT) system.

Testing Self-Similarity Through Lamperti Transformations

KAUST Repository

Lee, Myoungji

2016-07-14

Self-similar processes have been widely used in modeling real-world phenomena occurring in environmetrics, network traffic, image processing, and stock pricing, to name but a few. The estimation of the degree of self-similarity has been studied extensively, while statistical tests for self-similarity are scarce and limited to processes indexed in one dimension. This paper proposes a statistical hypothesis test procedure for self-similarity of a stochastic process indexed in one dimension and multi-self-similarity for a random field indexed in higher dimensions. If self-similarity is not rejected, our test provides a set of estimated self-similarity indexes. The key is to test stationarity of the inverse Lamperti transformations of the process. The inverse Lamperti transformation of a self-similar process is a strongly stationary process, revealing a theoretical connection between the two processes. To demonstrate the capability of our test, we test self-similarity of fractional Brownian motions and sheets, their time deformations and mixtures with Gaussian white noise, and the generalized Cauchy family. We also apply the self-similarity test to real data: annual minimum water levels of the Nile River, network traffic records, and surface heights of food wrappings. © 2016, International Biometric Society.

Sequence stratigraphy on an early wet Mars

Science.gov (United States)

Barker, Donald C.; Bhattacharya, Janok P.

2018-02-01

The evolution of Mars as a water-bearing body is of considerable interest for the understanding of its early history and evolution. The principles of terrestrial sequence stratigraphy provide a useful conceptual framework to hypothesize about the stratigraphic history of the planets northern plains. We present a model based on the hypothesized presence of an early ocean and the accumulation of lowland sediments eroded from highland terrain during the time of the valley networks and later outflow channels. Ancient, global environmental changes, induced by a progressively cooling climate would have led to a protracted loss of surface and near surface water from low-latitudes and eventual cold-trapping at higher latitudes - resulting in a unique and prolonged, perpetual forced regression within basins and lowland depositional environments. The Messinian Salinity Crisis (MSC) serves as a potential terrestrial analogue of the depositional and environmental consequences relating to the progressive removal of large standing bodies of water. We suggest that the evolution of similar conditions on Mars would have led to the emplacement of diagnostic sequences of deposits and regional scale unconformities, consistent with intermittent resurfacing of the northern plains and the progressive loss of an early ocean by the end of the Hesperian era.

Clinical evaluation of further-developed MRCP sequences in comparison with standard MRCP sequences

International Nuclear Information System (INIS)

Hundt, W.; Scheidler, J.; Reiser, M.; Petsch, R.

2002-01-01

The purpose of this study was the comparison of technically improved single-shot magnetic resonance cholangiopancreatography (MRCP) sequences with standard single-shot rapid acquisition with relaxation enhancement (RARE) and half-Fourier acquired single-shot turbo spin-echo (HASTE) sequences in evaluating the normal and abnormal biliary duct system. The bile duct system of 45 patients was prospectively investigated on a 1.5-T MRI system. The investigation was performed with RARE and HASTE MR cholangiography sequences with standard and high spatial resolutions, and with a delayed-echo half-Fourier RARE (HASTE) sequence. Findings of the improved MRCP sequences were compared with the standard MRCP sequences. The level of confidence in assessing the diagnosis was divided into five groups. The Wilcoxon signed-rank test at a level of p<0.05 was applied. In 15 patients no pathology was found. The MRCP showed stenoses of the bile duct system in 10 patients and choledocholithiasis and cholecystolithiasis in 16 patients. In 12 patients a dilatation of the bile duct system was found. Comparison of the low- and high spatial resolution sequences and the short and long TE times of the half-Fourier RARE (HASTE) sequence revealed no statistically significant differences regarding accuracy of the examination. The diagnostic confidence level in assessing normal or pathological findings for the high-resolution RARE and half-Fourier RARE (HASTE) was significantly better than for the standard sequences. For the delayed-echo half-Fourier RARE (HASTE) sequence no statistically significant difference was seen. The high-resolution RARE and half-Fourier RARE (HASTE) sequences had a higher confidence level, but there was no significant difference in diagnosis in terms of detection and assessment of pathological changes in the biliary duct system compared with standard sequences. (orig.)

Immunoinformatics and Similarity Analysis of House Dust Mite Tropomyosin

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Mohammad Mehdi Ranjbar

2015-10-01

Full Text Available Background: Dermatophagoides farinae and Dermatophagoides pteronyssinus are house dust mites (HDM that they cause severe asthma and allergic symptoms. Tropomyosin protein plays an important role in mentioned immune and allergic reactions to HDMs. Here, tropomyosin protein from Dermatophagoides spp. was comprehensively screened in silico for its allergenicity, antigenicity and similarity/conservation.Materials and Methods: The amino acid sequences of D. farinae tropomyosin, D. pteronyssinus and other mites were retrieved. We included alignments and evaluated conserved/ variable regions along sequences, constructed their phylogenetic tree and estimated overall mean distances. Then, followed by with prediction of linear B-cell epitope based on different approaches, and besides in-silico evaluation of IgE epitopes allergenicity (by SVMc, IgE epitope, ARPs BLAST, MAST and hybrid method. Finally, comparative analysis of results by different approaches was made.Results: Alignment results revealed near complete identity between D. farina and D. pteronyssinus members, and also there was close similarity among Dermatophagoides spp. Most of the variations among mites' tropomyosin were approximately located at amino acids 23 to 80, 108 to 120, 142 to 153 and 220 to 230. Topology of tree showed close relationships among mites in tropomyosin protein sequence, although their sequences in D. farina, D. pteronyssinus and Psoroptes ovis are more similar to each other and clustered. Dermanyssus gallinae (AC: Q2WBI0 has less relationship to other mites, being located in a separate branch. Hydrophilicity and flexibility plots revealed that many parts of this protein have potential to be hydrophilic and flexible. Surface accessibility represented 7 different epitopes. Beta-turns in this protein are with high probability in the middle part and its two terminals. Kolaskar and Tongaonkar method analysis represented 11 immunogenic epitopes between amino acids 7-16. From

FLAIR-HASTE sequence in differential diagnosis of focal hepatic lesions

International Nuclear Information System (INIS)

Kim, Yong Jae; Kim, Tae Kyoung; Bae, In Young; Kim, Pyo Nyun; Ha, Hyun Kwon; Kim, Ah Young; Lee, Moon Gyu

2001-01-01

To assess the feasibility of using the FLAIR (fluid-attenuated inversion recovery)-HASTE (half-fourier acquisition single-shot turbo spin-echo) sequence for the differential diagnosis of focal hepatic lesions. During a 12-month period, 80 patients with 127 focal hepatic lesions [hemangiomas (n=60), hepatocellular carcinomas (HCC) (n=27), cysts (n=25), and metastases (n=15) underwent MR imaging using a 1.5-T scanner. Verification of the diagnosis was based on the findings of pathology (n=11), of angiography and clinical investigation (n=17), or of dynamic contrast-enhanced MR imaging (n=99). MR sequences included T2-weighted HASTE (TE, 134 ms ; echo space, 4.4 ms), FLAIR-HASTE (TE, 64 ms ; echo space, 4.4 ms ; inversion time, 2000 ms ; number of slices, 5-9 ; acquisition time, 13-20 s), and dynamic gadolinium-enhanced T1-weighted FLASH (TR, 131 ms ; TE, 4 ms). FLAIR-HASTE imaging was of any focal lesions seen on T2-weighted HASTE images was performed in the liver area, and their signal intensity was classified in one of five ways : very high (higher than the spleen), moderately high (similar to the spleen), slightly high (higher than the liver and lower than the spleen), intermediate (similar to the liver), or low (lower than the liver). The signal intensity of the 25 cysts, as determined by FLAIR-HASTE, was low in 21 cases (84%), intermediate in three (12%), and very high in one (4%), which was diagnosed as a complicated cyst in which ultrasound revealed internal septa. At FLAIR-HASTE, all 60 hemangiomas showed either very high (n=50, 83%) or moderately high (n=10, 17%) signal intensity, while that of 42 hepatic malignant tumors was very high in 14 cases (33%), moderately high in 8 (19%), slightly high in 18 (43%), intermediate in one (2.5%), and low in one (2.5%). FLAIR-HASTE showed that the signal intensity of the majority of hepatic cysts was low, while that of most hemangiomas and solid liver tumors was high. For the differential diagnosis of cystic and

Planarian homeobox genes: cloning, sequence analysis, and expression.

Science.gov (United States)

Garcia-Fernàndez, J; Baguñà, J; Saló, E

1991-01-01

Freshwater planarians (Platyhelminthes, Turbellaria, and Tricladida) are acoelomate, triploblastic, unsegmented, and bilaterally symmetrical organisms that are mainly known for their ample power to regenerate a complete organism from a small piece of their body. To identify potential pattern-control genes in planarian regeneration, we have isolated two homeobox-containing genes, Dth-1 and Dth-2 [Dugesia (Girardia) tigrina homeobox], by using degenerate oligonucleotides corresponding to the most conserved amino acid sequence from helix-3 of the homeodomain. Dth-1 and Dth-2 homeodomains are closely related (68% at the nucleotide level and 78% at the protein level) and show the conserved residues characteristic of the homeodomains identified to data. Similarity with most homeobox sequences is low (30-50%), except with Drosophila NK homeodomains (80-82% with NK-2) and the rodent TTF-1 homeodomain (77-87%). Some unusual amino acid residues specific to NK-2, TTF-1, Dth-1, and Dth-2 can be observed in the recognition helix (helix-3) and may define a family of homeodomains. The deduced amino acid sequences from the cDNAs contain, in addition to the homeodomain, other domains also present in various homeobox-containing genes. The expression of both genes, detected by Northern blot analysis, appear slightly higher in cephalic regions than in the rest of the intact organism, while a slight increase is detected in the central period (5 days) or regeneration. Images PMID:1714599

Deep Sequencing Reveals the Complete Genome and Evidence for Transcriptional Activity of the First Virus-Like Sequences Identified in Aristotelia chilensis (Maqui Berry

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Javier Villacreses

2015-04-01

Full Text Available Here, we report the genome sequence and evidence for transcriptional activity of a virus-like element in the native Chilean berry tree Aristotelia chilensis. We propose to name the endogenous sequence as Aristotelia chilensis Virus 1 (AcV1. High-throughput sequencing of the genome of this tree uncovered an endogenous viral element, with a size of 7122 bp, corresponding to the complete genome of AcV1. Its sequence contains three open reading frames (ORFs: ORFs 1 and 2 shares 66%–73% amino acid similarity with members of the Caulimoviridae virus family, especially the Petunia vein clearing virus (PVCV, Petuvirus genus. ORF1 encodes a movement protein (MP; ORF2 a Reverse Transcriptase (RT and a Ribonuclease H (RNase H domain; and ORF3 showed no amino acid sequence similarity with any other known virus proteins. Analogous to other known endogenous pararetrovirus sequences (EPRVs, AcV1 is integrated in the genome of Maqui Berry and showed low viral transcriptional activity, which was detected by deep sequencing technology (DNA and RNA-seq. Phylogenetic analysis of AcV1 and other pararetroviruses revealed a closer resemblance with Petuvirus. Overall, our data suggests that AcV1 could be a new member of Caulimoviridae family, genus Petuvirus, and the first evidence of this kind of virus in a fruit plant.

Dominant accident sequences in Oconee-1 pressurized water reactor

International Nuclear Information System (INIS)

Dearing, J.F.; Henninger, R.J.; Nassersharif, B.

1985-04-01

A set of dominant accident sequences in the Oconee-1 pressurized water reactor was selected using probabilistic risk analysis methods. Because some accident scenarios were similar, a subset of four accident sequences was selected to be analyzed with the Transient Reactor Analysis Code (TRAC) to further our insights into similar types of accidents. The sequences selected were loss-of-feedwater, small-small break loss-of-coolant, loss-of-feedwater-initiated transient without scram, and interfacing systems loss-of-coolant accidents. The normal plant response and the impact of equipment availability and potential operator actions were also examined. Strategies were developed for operator actions not covered in existing emergency operator guidelines and were tested using TRAC simulations to evaluate their effectiveness in preventing core uncovery and maintaining core cooling

Whole-genome sequencing of veterinary pathogens

DEFF Research Database (Denmark)

Ronco, Troels

-electrophoresis and single-locus sequencing has been widely used to characterize such types of veterinary pathogens. However, DNA sequencing techniques have become fast and cost effective in recent years and whole-genome sequencing data provide a much higher discriminative power and reproducibility than any...... genetic background. This indicates that dairy cows can be natural carriers of S. aureus subtypes that in certain cases lead to CM. A group of isolates that mostly belonged to ST151 carried three pathogenicity islands that were primarily found in this group. The prevalence of resistance genes was generally...

Stepwise threshold clustering: a new method for genotyping MHC loci using next-generation sequencing technology.

Directory of Open Access Journals (Sweden)

William E Stutz

Full Text Available Genes of the vertebrate major histocompatibility complex (MHC are of great interest to biologists because of their important role in immunity and disease, and their extremely high levels of genetic diversity. Next generation sequencing (NGS technologies are quickly becoming the method of choice for high-throughput genotyping of multi-locus templates like MHC in non-model organisms. Previous approaches to genotyping MHC genes using NGS technologies suffer from two problems:1 a "gray zone" where low frequency alleles and high frequency artifacts can be difficult to disentangle and 2 a similar sequence problem, where very similar alleles can be difficult to distinguish as two distinct alleles. Here were present a new method for genotyping MHC loci--Stepwise Threshold Clustering (STC--that addresses these problems by taking full advantage of the increase in sequence data provided by NGS technologies. Unlike previous approaches for genotyping MHC with NGS data that attempt to classify individual sequences as alleles or artifacts, STC uses a quasi-Dirichlet clustering algorithm to cluster similar sequences at increasing levels of sequence similarity. By applying frequency and similarity based criteria to clusters rather than individual sequences, STC is able to successfully identify clusters of sequences that correspond to individual or similar alleles present in the genomes of individual samples. Furthermore, STC does not require duplicate runs of all samples, increasing the number of samples that can be genotyped in a given project. We show how the STC method works using a single sample library. We then apply STC to 295 threespine stickleback (Gasterosteus aculeatus samples from four populations and show that neighboring populations differ significantly in MHC allele pools. We show that STC is a reliable, accurate, efficient, and flexible method for genotyping MHC that will be of use to biologists interested in a variety of downstream applications.

Protein sequence comparison and protein evolution

Energy Technology Data Exchange (ETDEWEB)

Pearson, W.R. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Biochemistry

1995-12-31

This tutorial was one of eight tutorials selected to be presented at the Third International Conference on Intelligent Systems for Molecular Biology which was held in the United Kingdom from July 16 to 19, 1995. This tutorial examines how the information conserved during the evolution of a protein molecule can be used to infer reliably homology, and thus a shared proteinfold and possibly a shared active site or function. The authors start by reviewing a geological/evolutionary time scale. Next they look at the evolution of several protein families. During the tutorial, these families will be used to demonstrate that homologous protein ancestry can be inferred with confidence. They also examine different modes of protein evolution and consider some hypotheses that have been presented to explain the very earliest events in protein evolution. The next part of the tutorial will examine the technical aspects of protein sequence comparison. Both optimal and heuristic algorithms and their associated parameters that are used to characterize protein sequence similarities are discussed. Perhaps more importantly, they survey the statistics of local similarity scores, and how these statistics can both be used to improve the selectivity of a search and to evaluate the significance of a match. They them examine distantly related members of three protein families, the serine proteases, the glutathione transferases, and the G-protein-coupled receptors (GCRs). Finally, the discuss how sequence similarity can be used to examine internal repeated or mosaic structures in proteins.

Robust Automatic Target Recognition via HRRP Sequence Based on Scatterer Matching

Directory of Open Access Journals (Sweden)

Yuan Jiang

2018-02-01

Full Text Available High resolution range profile (HRRP plays an important role in wideband radar automatic target recognition (ATR. In order to alleviate the sensitivity to clutter and target aspect, employing a sequence of HRRP is a promising approach to enhance the ATR performance. In this paper, a novel HRRP sequence-matching method based on singular value decomposition (SVD is proposed. First, the HRRP sequence is decoupled into the angle space and the range space via SVD, which correspond to the span of the left and the right singular vectors, respectively. Second, atomic norm minimization (ANM is utilized to estimate dominant scatterers in the range space and the Hausdorff distance is employed to measure the scatter similarity between the test and training data. Next, the angle space similarity between the test and training data is evaluated based on the left singular vector correlations. Finally, the range space matching result and the angle space correlation are fused with the singular values as weights. Simulation and outfield experimental results demonstrate that the proposed matching metric is a robust similarity measure for HRRP sequence recognition.

Google matrix analysis of DNA sequences.

Science.gov (United States)

Kandiah, Vivek; Shepelyansky, Dima L

2013-01-01

For DNA sequences of various species we construct the Google matrix [Formula: see text] of Markov transitions between nearby words composed of several letters. The statistical distribution of matrix elements of this matrix is shown to be described by a power law with the exponent being close to those of outgoing links in such scale-free networks as the World Wide Web (WWW). At the same time the sum of ingoing matrix elements is characterized by the exponent being significantly larger than those typical for WWW networks. This results in a slow algebraic decay of the PageRank probability determined by the distribution of ingoing elements. The spectrum of [Formula: see text] is characterized by a large gap leading to a rapid relaxation process on the DNA sequence networks. We introduce the PageRank proximity correlator between different species which determines their statistical similarity from the view point of Markov chains. The properties of other eigenstates of the Google matrix are also discussed. Our results establish scale-free features of DNA sequence networks showing their similarities and distinctions with the WWW and linguistic networks.

Google matrix analysis of DNA sequences.

Directory of Open Access Journals (Sweden)

Vivek Kandiah

Full Text Available For DNA sequences of various species we construct the Google matrix [Formula: see text] of Markov transitions between nearby words composed of several letters. The statistical distribution of matrix elements of this matrix is shown to be described by a power law with the exponent being close to those of outgoing links in such scale-free networks as the World Wide Web (WWW. At the same time the sum of ingoing matrix elements is characterized by the exponent being significantly larger than those typical for WWW networks. This results in a slow algebraic decay of the PageRank probability determined by the distribution of ingoing elements. The spectrum of [Formula: see text] is characterized by a large gap leading to a rapid relaxation process on the DNA sequence networks. We introduce the PageRank proximity correlator between different species which determines their statistical similarity from the view point of Markov chains. The properties of other eigenstates of the Google matrix are also discussed. Our results establish scale-free features of DNA sequence networks showing their similarities and distinctions with the WWW and linguistic networks.

Prediction of novel archaeal enzymes from sequence-derived features

DEFF Research Database (Denmark)

Jensen, Lars Juhl; Skovgaard, Marie; Brunak, Søren

2002-01-01

The completely sequenced archaeal genomes potentially encode, among their many functionally uncharacterized genes, novel enzymes of biotechnological interest. We have developed a prediction method for detection and classification of enzymes from sequence alone (available at http://www.cbs.dtu.dk/......The completely sequenced archaeal genomes potentially encode, among their many functionally uncharacterized genes, novel enzymes of biotechnological interest. We have developed a prediction method for detection and classification of enzymes from sequence alone (available at http......://www.cbs.dtu.dk/services/ArchaeaFun/). The method does not make use of sequence similarity; rather, it relies on predicted protein features like cotranslational and posttranslational modifications, secondary structure, and simple physical/chemical properties....

Complete genome sequence of a novel pestivirus from sheep.

Science.gov (United States)

Becher, Paul; Schmeiser, Stefanie; Oguzoglu, Tuba Cigdem; Postel, Alexander

2012-10-01

We report here the complete genome sequence of pestivirus strain Aydin/04-TR, which is the prototype of a group of similar viruses currently present in sheep and goats in Turkey. Sequence data from this virus showed that it clusters separately from the established and previously proposed tentative pestivirus species.

Complete Genome Sequence of a Novel Pestivirus from Sheep

OpenAIRE

Becher, Paul; Schmeiser, Stefanie; Oguzoglu, Tuba Cigdem; Postel, Alexander

2012-01-01

We report here the complete genome sequence of pestivirus strain Aydin/04-TR, which is the prototype of a group of similar viruses currently present in sheep and goats in Turkey. Sequence data from this virus showed that it clusters separately from the established and previously proposed tentative pestivirus species.

Evidence for deep regulatory similarities in early developmental programs across highly diverged insects.

Science.gov (United States)

Kazemian, Majid; Suryamohan, Kushal; Chen, Jia-Yu; Zhang, Yinan; Samee, Md Abul Hassan; Halfon, Marc S; Sinha, Saurabh

2014-09-01

Many genes familiar from Drosophila development, such as the so-called gap, pair-rule, and segment polarity genes, play important roles in the development of other insects and in many cases appear to be deployed in a similar fashion, despite the fact that Drosophila-like "long germband" development is highly derived and confined to a subset of insect families. Whether or not these similarities extend to the regulatory level is unknown. Identification of regulatory regions beyond the well-studied Drosophila has been challenging as even within the Diptera (flies, including mosquitoes) regulatory sequences have diverged past the point of recognition by standard alignment methods. Here, we demonstrate that methods we previously developed for computational cis-regulatory module (CRM) discovery in Drosophila can be used effectively in highly diverged (250-350 Myr) insect species including Anopheles gambiae, Tribolium castaneum, Apis mellifera, and Nasonia vitripennis. In Drosophila, we have successfully used small sets of known CRMs as "training data" to guide the search for other CRMs with related function. We show here that although species-specific CRM training data do not exist, training sets from Drosophila can facilitate CRM discovery in diverged insects. We validate in vivo over a dozen new CRMs, roughly doubling the number of known CRMs in the four non-Drosophila species. Given the growing wealth of Drosophila CRM annotation, these results suggest that extensive regulatory sequence annotation will be possible in newly sequenced insects without recourse to costly and labor-intensive genome-scale experiments. We develop a new method, Regulus, which computes a probabilistic score of similarity based on binding site composition (despite the absence of nucleotide-level sequence alignment), and demonstrate similarity between functionally related CRMs from orthologous loci. Our work represents an important step toward being able to trace the evolutionary history of gene

Evidence for Deep Regulatory Similarities in Early Developmental Programs across Highly Diverged Insects

Science.gov (United States)

Zhang, Yinan; Samee, Md. Abul Hassan; Halfon, Marc S.; Sinha, Saurabh

2014-01-01

Many genes familiar from Drosophila development, such as the so-called gap, pair-rule, and segment polarity genes, play important roles in the development of other insects and in many cases appear to be deployed in a similar fashion, despite the fact that Drosophila-like “long germband” development is highly derived and confined to a subset of insect families. Whether or not these similarities extend to the regulatory level is unknown. Identification of regulatory regions beyond the well-studied Drosophila has been challenging as even within the Diptera (flies, including mosquitoes) regulatory sequences have diverged past the point of recognition by standard alignment methods. Here, we demonstrate that methods we previously developed for computational cis-regulatory module (CRM) discovery in Drosophila can be used effectively in highly diverged (250–350 Myr) insect species including Anopheles gambiae, Tribolium castaneum, Apis mellifera, and Nasonia vitripennis. In Drosophila, we have successfully used small sets of known CRMs as “training data” to guide the search for other CRMs with related function. We show here that although species-specific CRM training data do not exist, training sets from Drosophila can facilitate CRM discovery in diverged insects. We validate in vivo over a dozen new CRMs, roughly doubling the number of known CRMs in the four non-Drosophila species. Given the growing wealth of Drosophila CRM annotation, these results suggest that extensive regulatory sequence annotation will be possible in newly sequenced insects without recourse to costly and labor-intensive genome-scale experiments. We develop a new method, Regulus, which computes a probabilistic score of similarity based on binding site composition (despite the absence of nucleotide-level sequence alignment), and demonstrate similarity between functionally related CRMs from orthologous loci. Our work represents an important step toward being able to trace the evolutionary

Divide and conquer: enriching environmental sequencing data.

Directory of Open Access Journals (Sweden)

Anne Bergeron

2007-09-01

Full Text Available In environmental sequencing projects, a mix of DNA from a whole microbial community is fragmented and sequenced, with one of the possible goals being to reconstruct partial or complete genomes of members of the community. In communities with high diversity of species, a significant proportion of the sequences do not overlap any other fragment in the sample. This problem will arise not only in situations with a relatively even distribution of many species, but also when the community in a particular environment is routinely dominated by the same few species. In the former case, no genomes may be assembled at all, while in the latter case a few dominant species in an environment will always be sequenced at high coverage to the detriment of coverage of the greater number of sparse species.Here we show that, with the same global sequencing effort, separating the species into two or more sub-communities prior to sequencing can yield a much higher proportion of sequences that can be assembled. We first use the Lander-Waterman model to show that, if the expected percentage of singleton sequences is higher than 25%, then, under the uniform distribution hypothesis, splitting the community is always a wise choice. We then construct simulated microbial communities to show that the results hold for highly non-uniform distributions. We also show that, for the distributions considered in the experiments, it is possible to estimate quite accurately the relative diversity of the two sub-communities.Given the fact that several methods exist to split microbial communities based on physical properties such as size, density, surface biochemistry, or optical properties, we strongly suggest that groups involved in environmental sequencing, and expecting high diversity, consider splitting their communities in order to maximize the information content of their sequencing effort.

Memory and learning with rapid audiovisual sequences

Science.gov (United States)

Keller, Arielle S.; Sekuler, Robert

2015-01-01

We examined short-term memory for sequences of visual stimuli embedded in varying multisensory contexts. In two experiments, subjects judged the structure of the visual sequences while disregarding concurrent, but task-irrelevant auditory sequences. Stimuli were eight-item sequences in which varying luminances and frequencies were presented concurrently and rapidly (at 8 Hz). Subjects judged whether the final four items in a visual sequence identically replicated the first four items. Luminances and frequencies in each sequence were either perceptually correlated (Congruent) or were unrelated to one another (Incongruent). Experiment 1 showed that, despite encouragement to ignore the auditory stream, subjects' categorization of visual sequences was strongly influenced by the accompanying auditory sequences. Moreover, this influence tracked the similarity between a stimulus's separate audio and visual sequences, demonstrating that task-irrelevant auditory sequences underwent a considerable degree of processing. Using a variant of Hebb's repetition design, Experiment 2 compared musically trained subjects and subjects who had little or no musical training on the same task as used in Experiment 1. Test sequences included some that intermittently and randomly recurred, which produced better performance than sequences that were generated anew for each trial. The auditory component of a recurring audiovisual sequence influenced musically trained subjects more than it did other subjects. This result demonstrates that stimulus-selective, task-irrelevant learning of sequences can occur even when such learning is an incidental by-product of the task being performed. PMID:26575193

Memory and learning with rapid audiovisual sequences.

Science.gov (United States)

Keller, Arielle S; Sekuler, Robert

2015-01-01

We examined short-term memory for sequences of visual stimuli embedded in varying multisensory contexts. In two experiments, subjects judged the structure of the visual sequences while disregarding concurrent, but task-irrelevant auditory sequences. Stimuli were eight-item sequences in which varying luminances and frequencies were presented concurrently and rapidly (at 8 Hz). Subjects judged whether the final four items in a visual sequence identically replicated the first four items. Luminances and frequencies in each sequence were either perceptually correlated (Congruent) or were unrelated to one another (Incongruent). Experiment 1 showed that, despite encouragement to ignore the auditory stream, subjects' categorization of visual sequences was strongly influenced by the accompanying auditory sequences. Moreover, this influence tracked the similarity between a stimulus's separate audio and visual sequences, demonstrating that task-irrelevant auditory sequences underwent a considerable degree of processing. Using a variant of Hebb's repetition design, Experiment 2 compared musically trained subjects and subjects who had little or no musical training on the same task as used in Experiment 1. Test sequences included some that intermittently and randomly recurred, which produced better performance than sequences that were generated anew for each trial. The auditory component of a recurring audiovisual sequence influenced musically trained subjects more than it did other subjects. This result demonstrates that stimulus-selective, task-irrelevant learning of sequences can occur even when such learning is an incidental by-product of the task being performed.

Enhanced Dynamic Algorithm of Genome Sequence Alignments

OpenAIRE

Arabi E. keshk

2014-01-01

The merging of biology and computer science has created a new field called computational biology that explore the capacities of computers to gain knowledge from biological data, bioinformatics. Computational biology is rooted in life sciences as well as computers, information sciences, and technologies. The main problem in computational biology is sequence alignment that is a way of arranging the sequences of DNA, RNA or protein to identify the region of similarity and relationship between se...

Cross-kingdom similarities in microbiome functions

NARCIS (Netherlands)

Mendes, R.; Raaijmakers, J.M.

2015-01-01

Recent advances in medical research have revealed how humans rely on their microbiome for diverse traits and functions. Similarly, microbiomes of other higher organisms play key roles in disease, health, growth and development of their host. Exploring microbiome functions across kingdoms holds

Prediction of Antimicrobial Peptides Based on Sequence Alignment and Support Vector Machine-Pairwise Algorithm Utilizing LZ-Complexity

Directory of Open Access Journals (Sweden)

Xin Yi Ng

2015-01-01

Full Text Available This study concerns an attempt to establish a new method for predicting antimicrobial peptides (AMPs which are important to the immune system. Recently, researchers are interested in designing alternative drugs based on AMPs because they have found that a large number of bacterial strains have become resistant to available antibiotics. However, researchers have encountered obstacles in the AMPs designing process as experiments to extract AMPs from protein sequences are costly and require a long set-up time. Therefore, a computational tool for AMPs prediction is needed to resolve this problem. In this study, an integrated algorithm is newly introduced to predict AMPs by integrating sequence alignment and support vector machine- (SVM- LZ complexity pairwise algorithm. It was observed that, when all sequences in the training set are used, the sensitivity of the proposed algorithm is 95.28% in jackknife test and 87.59% in independent test, while the sensitivity obtained for jackknife test and independent test is 88.74% and 78.70%, respectively, when only the sequences that has less than 70% similarity are used. Applying the proposed algorithm may allow researchers to effectively predict AMPs from unknown protein peptide sequences with higher sensitivity.

Genomic Analysis of a Marine Bacterium: Bioinformatics for Comparison, Evaluation, and Interpretation of DNA Sequences

Directory of Open Access Journals (Sweden)

Bhagwan N. Rekadwad

2016-01-01

Full Text Available A total of five highly related strains of an unidentified marine bacterium were analyzed through their short genome sequences (AM260709–AM260713. Genome-to-Genome Distance (GGDC showed high similarity to Pseudoalteromonas haloplanktis (X67024. The generated unique Quick Response (QR codes indicated no identity to other microbial species or gene sequences. Chaos Game Representation (CGR showed the number of bases concentrated in the area. Guanine residues were highest in number followed by cytosine. Frequency of Chaos Game Representation (FCGR indicated that CC and GG blocks have higher frequency in the sequence from the evaluated marine bacterium strains. Maximum GC content for the marine bacterium strains ranged 53-54%. The use of QR codes, CGR, FCGR, and GC dataset helped in identifying and interpreting short genome sequences from specific isolates. A phylogenetic tree was constructed with the bootstrap test (1000 replicates using MEGA6 software. Principal Component Analysis (PCA was carried out using EMBL-EBI MUSCLE program. Thus, generated genomic data are of great assistance for hierarchical classification in Bacterial Systematics which combined with phenotypic features represents a basic procedure for a polyphasic approach on unambiguous bacterial isolate taxonomic classification.

Discrete Self-Similarity in Interfacial Hydrodynamics and the Formation of Iterated Structures.

Science.gov (United States)

Dallaston, Michael C; Fontelos, Marco A; Tseluiko, Dmitri; Kalliadasis, Serafim

2018-01-19

The formation of iterated structures, such as satellite and subsatellite drops, filaments, and bubbles, is a common feature in interfacial hydrodynamics. Here we undertake a computational and theoretical study of their origin in the case of thin films of viscous fluids that are destabilized by long-range molecular or other forces. We demonstrate that iterated structures appear as a consequence of discrete self-similarity, where certain patterns repeat themselves, subject to rescaling, periodically in a logarithmic time scale. The result is an infinite sequence of ridges and filaments with similarity properties. The character of these discretely self-similar solutions as the result of a Hopf bifurcation from ordinarily self-similar solutions is also described.

Multifractal and higher-dimensional zeta functions

International Nuclear Information System (INIS)

Véhel, Jacques Lévy; Mendivil, Franklin

2011-01-01

In this paper, we generalize the zeta function for a fractal string (as in Lapidus and Frankenhuijsen 2006 Fractal Geometry, Complex Dimensions and Zeta Functions: Geometry and Spectra of Fractal Strings (New York: Springer)) in several directions. We first modify the zeta function to be associated with a sequence of covers instead of the usual definition involving gap lengths. This modified zeta function allows us to define both a multifractal zeta function and a zeta function for higher-dimensional fractal sets. In the multifractal case, the critical exponents of the zeta function ζ(q, s) yield the usual multifractal spectrum of the measure. The presence of complex poles for ζ(q, s) indicates oscillations in the continuous partition function of the measure, and thus gives more refined information about the multifractal spectrum of a measure. In the case of a self-similar set in R n , the modified zeta function yields asymptotic information about both the 'box' counting function of the set and the n-dimensional volume of the ε-dilation of the set

Phylogenetic characterization of a biogas plant microbial community integrating clone library 16S-rDNA sequences and metagenome sequence data obtained by 454-pyrosequencing.

Science.gov (United States)

Kröber, Magdalena; Bekel, Thomas; Diaz, Naryttza N; Goesmann, Alexander; Jaenicke, Sebastian; Krause, Lutz; Miller, Dimitri; Runte, Kai J; Viehöver, Prisca; Pühler, Alfred; Schlüter, Andreas

2009-06-01

The phylogenetic structure of the microbial community residing in a fermentation sample from a production-scale biogas plant fed with maize silage, green rye and liquid manure was analysed by an integrated approach using clone library sequences and metagenome sequence data obtained by 454-pyrosequencing. Sequencing of 109 clones from a bacterial and an archaeal 16S-rDNA amplicon library revealed that the obtained nucleotide sequences are similar but not identical to 16S-rDNA database sequences derived from different anaerobic environments including digestors and bioreactors. Most of the bacterial 16S-rDNA sequences could be assigned to the phylum Firmicutes with the most abundant class Clostridia and to the class Bacteroidetes, whereas most archaeal 16S-rDNA sequences cluster close to the methanogen Methanoculleus bourgensis. Further sequences of the archaeal library most probably represent so far non-characterised species within the genus Methanoculleus. A similar result derived from phylogenetic analysis of mcrA clone sequences. The mcrA gene product encodes the alpha-subunit of methyl-coenzyme-M reductase involved in the final step of methanogenesis. BLASTn analysis applying stringent settings resulted in assignment of 16S-rDNA metagenome sequence reads to 62 16S-rDNA amplicon sequences thus enabling frequency of abundance estimations for 16S-rDNA clone library sequences. Ribosomal Database Project (RDP) Classifier processing of metagenome 16S-rDNA reads revealed abundance of the phyla Firmicutes, Bacteroidetes and Euryarchaeota and the orders Clostridiales, Bacteroidales and Methanomicrobiales. Moreover, a large fraction of 16S-rDNA metagenome reads could not be assigned to lower taxonomic ranks, demonstrating that numerous microorganisms in the analysed fermentation sample of the biogas plant are still unclassified or unknown.

Twenty-one genome sequences from Pseudomonas species and 19 genome sequences from diverse bacteria isolated from the rhizosphere and endosphere of Populus deltoides.

Science.gov (United States)

Brown, Steven D; Utturkar, Sagar M; Klingeman, Dawn M; Johnson, Courtney M; Martin, Stanton L; Land, Miriam L; Lu, Tse-Yuan S; Schadt, Christopher W; Doktycz, Mitchel J; Pelletier, Dale A

2012-11-01

To aid in the investigation of the Populus deltoides microbiome, we generated draft genome sequences for 21 Pseudomonas strains and 19 other diverse bacteria isolated from Populus deltoides roots. Genome sequences for isolates similar to Acidovorax, Bradyrhizobium, Brevibacillus, Caulobacter, Chryseobacterium, Flavobacterium, Herbaspirillum, Novosphingobium, Pantoea, Phyllobacterium, Polaromonas, Rhizobium, Sphingobium, and Variovorax were generated.

Exploration of noncoding sequences in metagenomes.

Directory of Open Access Journals (Sweden)

Fabián Tobar-Tosse

Full Text Available Environment-dependent genomic features have been defined for different metagenomes, whose genes and their associated processes are related to specific environments. Identification of ORFs and their functional categories are the most common methods for association between functional and environmental features. However, this analysis based on finding ORFs misses noncoding sequences and, therefore, some metagenome regulatory or structural information could be discarded. In this work we analyzed 23 whole metagenomes, including coding and noncoding sequences using the following sequence patterns: (G+C content, Codon Usage (Cd, Trinucleotide Usage (Tn, and functional assignments for ORF prediction. Herein, we present evidence of a high proportion of noncoding sequences discarded in common similarity-based methods in metagenomics, and the kind of relevant information present in those. We found a high density of trinucleotide repeat sequences (TRS in noncoding sequences, with a regulatory and adaptive function for metagenome communities. We present associations between trinucleotide values and gene function, where metagenome clustering correlate with microorganism adaptations and kinds of metagenomes. We propose here that noncoding sequences have relevant information to describe metagenomes that could be considered in a whole metagenome analysis in order to improve their organization, classification protocols, and their relation with the environment.

Dynamics based alignment of proteins: an alternative approach to quantify dynamic similarity

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Lyngsø Rune

2010-04-01

Full Text Available Abstract Background The dynamic motions of many proteins are central to their function. It therefore follows that the dynamic requirements of a protein are evolutionary constrained. In order to assess and quantify this, one needs to compare the dynamic motions of different proteins. Comparing the dynamics of distinct proteins may also provide insight into how protein motions are modified by variations in sequence and, consequently, by structure. The optimal way of comparing complex molecular motions is, however, far from trivial. The majority of comparative molecular dynamics studies performed to date relied upon prior sequence or structural alignment to define which residues were equivalent in 3-dimensional space. Results Here we discuss an alternative methodology for comparative molecular dynamics that does not require any prior alignment information. We show it is possible to align proteins based solely on their dynamics and that we can use these dynamics-based alignments to quantify the dynamic similarity of proteins. Our method was tested on 10 representative members of the PDZ domain family. Conclusions As a result of creating pair-wise dynamics-based alignments of PDZ domains, we have found evolutionarily conserved patterns in their backbone dynamics. The dynamic similarity of PDZ domains is highly correlated with their structural similarity as calculated with Dali. However, significant differences in their dynamics can be detected indicating that sequence has a more refined role to play in protein dynamics than just dictating the overall fold. We suggest that the method should be generally applicable.

Vere-Jones' self-similar branching model

International Nuclear Information System (INIS)

Saichev, A.; Sornette, D.

2005-01-01

Motivated by its potential application to earthquake statistics as well as for its intrinsic interest in the theory of branching processes, we study the exactly self-similar branching process introduced recently by Vere-Jones. This model extends the ETAS class of conditional self-excited branching point-processes of triggered seismicity by removing the problematic need for a minimum (as well as maximum) earthquake size. To make the theory convergent without the need for the usual ultraviolet and infrared cutoffs, the distribution of magnitudes m ' of daughters of first-generation of a mother of magnitude m has two branches m ' ' >m with exponent β+d, where β and d are two positive parameters. We investigate the condition and nature of the subcritical, critical, and supercritical regime in this and in an extended version interpolating smoothly between several models. We predict that the distribution of magnitudes of events triggered by a mother of magnitude m over all generations has also two branches m ' ' >m with exponent β+h, with h=d√(1-s), where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. For a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources with a single branch and is blind to the exponents β,d of the distribution of triggered events. Since the distribution of earthquake magnitudes is usually obtained with catalogs including many sequences, we conclude that the two branches of the distribution of aftershocks are not directly observable and the model is compatible with real seismic catalogs. In summary, the exactly self-similar Vere-Jones model provides an attractive new approach to model triggered seismicity, which alleviates delicate questions on the role of

Complete chloroplast DNA sequence from a Korean endemic genus, Megaleranthis saniculifolia, and its evolutionary implications.

Science.gov (United States)

Kim, Young-Kyu; Park, Chong-wook; Kim, Ki-Joong

2009-03-31

The chloroplast DNA sequences of Megaleranthis saniculifolia, an endemic and monotypic endangered plant species, were completed in this study (GenBank FJ597983). The genome is 159,924 bp in length. It harbors a pair of IR regions consisting of 26,608 bp each. The lengths of the LSC and SSC regions are 88,326 bp and 18,382 bp, respectively. The structural organizations, gene and intron contents, gene orders, AT contents, codon usages, and transcription units of the Megaleranthis chloroplast genome are similar to those of typical land plant cp DNAs. However, the detailed features of Megaleranthis chloroplast genomes are substantially different from that of Ranunculus, which belongs to the same family, the Ranunculaceae. First, the Megaleranthis cp DNA was 4,797 bp longer than that of Ranunculus due to an expanded IR region into the SSC region and duplicated sequence elements in several spacer regions of the Megaleranthis cp genome. Second, the chloroplast genomes of Megaleranthis and Ranunculus evidence 5.6% sequence divergence in the coding regions, 8.9% sequence divergence in the intron regions, and 18.7% sequence divergence in the intergenic spacer regions, respectively. In both the coding and noncoding regions, average nucleotide substitution rates differed markedly, depending on the genome position. Our data strongly implicate the positional effects of the evolutionary modes of chloroplast genes. The genes evidencing higher levels of base substitutions also have higher incidences of indel mutations and low Ka/Ks ratios. A total of 54 simple sequence repeat loci were identified from the Megaleranthis cp genome. The existence of rich cp SSR loci in the Megaleranthis cp genome provides a rare opportunity to study the population genetic structures of this endangered species. Our phylogenetic trees based on the two independent markers, the nuclear ITS and chloroplast matK sequences, strongly support the inclusion of the Megaleranthis to the Trollius. Therefore, our

Twenty-One Genome Sequences from Pseudomonas Species and 19 Genome Sequences from Diverse Bacteria Isolated from the Rhizosphere and Endosphere of Populus deltoides

Energy Technology Data Exchange (ETDEWEB)

Brown, Steven D [ORNL; Utturkar, Sagar M [ORNL; Klingeman, Dawn Marie [ORNL; Johnson, Courtney M [ORNL; Martin, Stanton [ORNL; Land, Miriam L [ORNL; Lu, Tse-Yuan [ORNL; Schadt, Christopher Warren [ORNL; Doktycz, Mitchel John [ORNL; Pelletier, Dale A [ORNL

2012-01-01

To aid in the investigation of the Populus deltoides microbiome we generated draft genome sequences for twenty one Pseudomonas and twenty one other diverse bacteria isolated from Populus deltoides roots. Genome sequences for isolates similar to Acidovorax, Bradyrhizobium, Brevibacillus, Burkholderia, Caulobacter, Chryseobacterium, Flavobacterium, Herbaspirillum, Novosphingobium, Pantoea, Phyllobacterium, Polaromonas, Rhizobium, Sphingobium and Variovorax were generated.

Rapid discrimination and classification of the Lactobacillus plantarum group based on a partial dnaK sequence and DNA fingerprinting techniques.

Science.gov (United States)

Huang, Chien-Hsun; Lee, Fwu-Ling; Liou, Jong-Shian

2010-03-01

The Lactobacillus plantarum group comprises five very closely related species. Some species of this group are considered to be probiotic and widely applied in the food industry. In this study, we compared the use of two different molecular markers, the 16S rRNA and dnaK gene, for discriminating phylogenetic relationships amongst L. plantarum strains using sequencing and DNA fingerprinting. The average sequence similarity for the dnaK gene (89.2%) among five type strains was significantly less than that for the 16S rRNA (99.4%). This result demonstrates that the dnaK gene sequence provided higher resolution than the 16S rRNA and suggests that the dnaK could be used as an additional phylogenetic marker for L. plantarum. Species-specific profiles of the Lactobacillus strains were obtained with RAPD and RFLP methods. Our data indicate that phylogenetic relationships between these strains are easily resolved using sequencing of the dnaK gene or DNA fingerprinting assays.

Whole Genome Sequences of Three Treponema pallidum ssp. pertenue Strains: Yaws and Syphilis Treponemes Differ in Less than 0.2% of the Genome Sequence

Science.gov (United States)

Chen, Lei; Pospíšilová, Petra; Strouhal, Michal; Qin, Xiang; Mikalová, Lenka; Norris, Steven J.; Muzny, Donna M.; Gibbs, Richard A.; Fulton, Lucinda L.; Sodergren, Erica; Weinstock, George M.; Šmajs, David

2012-01-01

Background The yaws treponemes, Treponema pallidum ssp. pertenue (TPE) strains, are closely related to syphilis causing strains of Treponema pallidum ssp. pallidum (TPA). Both yaws and syphilis are distinguished on the basis of epidemiological characteristics, clinical symptoms, and several genetic signatures of the corresponding causative agents. Methodology/Principal Findings To precisely define genetic differences between TPA and TPE, high-quality whole genome sequences of three TPE strains (Samoa D, CDC-2, Gauthier) were determined using next-generation sequencing techniques. TPE genome sequences were compared to four genomes of TPA strains (Nichols, DAL-1, SS14, Chicago). The genome structure was identical in all three TPE strains with similar length ranging between 1,139,330 bp and 1,139,744 bp. No major genome rearrangements were found when compared to the four TPA genomes. The whole genome nucleotide divergence (dA) between TPA and TPE subspecies was 4.7 and 4.8 times higher than the observed nucleotide diversity (π) among TPA and TPE strains, respectively, corresponding to 99.8% identity between TPA and TPE genomes. A set of 97 (9.9%) TPE genes encoded proteins containing two or more amino acid replacements or other major sequence changes. The TPE divergent genes were mostly from the group encoding potential virulence factors and genes encoding proteins with unknown function. Conclusions/Significance Hypothetical genes, with genetic differences, consistently found between TPE and TPA strains are candidates for syphilitic treponemes virulence factors. Seventeen TPE genes were predicted under positive selection, and eleven of them coded either for predicted exported proteins or membrane proteins suggesting their possible association with the cell surface. Sequence changes between TPE and TPA strains and changes specific to individual strains represent suitable targets for subspecies- and strain-specific molecular diagnostics. PMID:22292095

Detecting change in stochastic sound sequences.

Directory of Open Access Journals (Sweden)

Benjamin Skerritt-Davis

2018-05-01

Full Text Available Our ability to parse our acoustic environment relies on the brain's capacity to extract statistical regularities from surrounding sounds. Previous work in regularity extraction has predominantly focused on the brain's sensitivity to predictable patterns in sound sequences. However, natural sound environments are rarely completely predictable, often containing some level of randomness, yet the brain is able to effectively interpret its surroundings by extracting useful information from stochastic sounds. It has been previously shown that the brain is sensitive to the marginal lower-order statistics of sound sequences (i.e., mean and variance. In this work, we investigate the brain's sensitivity to higher-order statistics describing temporal dependencies between sound events through a series of change detection experiments, where listeners are asked to detect changes in randomness in the pitch of tone sequences. Behavioral data indicate listeners collect statistical estimates to process incoming sounds, and a perceptual model based on Bayesian inference shows a capacity in the brain to track higher-order statistics. Further analysis of individual subjects' behavior indicates an important role of perceptual constraints in listeners' ability to track these sensory statistics with high fidelity. In addition, the inference model facilitates analysis of neural electroencephalography (EEG responses, anchoring the analysis relative to the statistics of each stochastic stimulus. This reveals both a deviance response and a change-related disruption in phase of the stimulus-locked response that follow the higher-order statistics. These results shed light on the brain's ability to process stochastic sound sequences.

Solving Classification Problems for Large Sets of Protein Sequences with the Example of Hox and ParaHox Proteins

Directory of Open Access Journals (Sweden)

Stefanie D. Hueber

2016-02-01

Full Text Available Phylogenetic methods are key to providing models for how a given protein family evolved. However, these methods run into difficulties when sequence divergence is either too low or too high. Here, we provide a case study of Hox and ParaHox proteins so that additional insights can be gained using a new computational approach to help solve old classification problems. For two (Gsx and Cdx out of three ParaHox proteins the assignments differ between the currently most established view and four alternative scenarios. We use a non-phylogenetic, pairwise-sequence-similarity-based method to assess which of the previous predictions, if any, are best supported by the sequence-similarity relationships between Hox and ParaHox proteins. The overall sequence-similarities show Gsx to be most similar to Hox2–3, and Cdx to be most similar to Hox4–8. The results indicate that a purely pairwise-sequence-similarity-based approach can provide additional information not only when phylogenetic inference methods have insufficient information to provide reliable classifications (as was shown previously for central Hox proteins, but also when the sequence variation is so high that the resulting phylogenetic reconstructions are likely plagued by long-branch-attraction artifacts.

Effect of sequence dispersity on morphology of tapered diblock copolymers from molecular dynamics simulations.

Science.gov (United States)

Levine, William G; Seo, Youngmi; Brown, Jonathan R; Hall, Lisa M

2016-12-21

Tapered diblock copolymers are similar to typical AB diblock copolymers but have an added transition region between the two blocks which changes gradually in composition from pure A to pure B. This tapered region can be varied from 0% (true diblock) to 100% (gradient copolymer) of the polymer length, and this allows some control over the microphase separated domain spacing and other material properties. We perform molecular dynamics simulations of linearly tapered block copolymers with tapers of various lengths, initialized from fluids density functional theory predictions. To investigate the effect of sequence dispersity, we compare systems composed of identical polymers, whose taper has a fixed sequence that most closely approximates a linear gradient, with sequentially disperse polymers, whose sequences are created statistically to yield the appropriate ensemble average linear gradient. Especially at high segregation strength, we find clear differences in polymer conformations and microstructures between these systems. Importantly, the statistical polymers are able to find more favorable conformations given their sequence, for instance, a statistical polymer with a larger fraction of A than the median will tend towards the A lamellae. The conformations of the statistically different polymers can thus be less stretched, and these systems have higher overall density. Consequently, the lamellae formed by statistical polymers have smaller domain spacing with sharper interfaces.

Molecular diagnosis of Usher syndrome: application of two different next generation sequencing-based procedures.

Directory of Open Access Journals (Sweden)

Danilo Licastro

Full Text Available Usher syndrome (USH is a clinically and genetically heterogeneous disorder characterized by visual and hearing impairments. Clinically, it is subdivided into three subclasses with nine genes identified so far. In the present study, we investigated whether the currently available Next Generation Sequencing (NGS technologies are already suitable for molecular diagnostics of USH. We analyzed a total of 12 patients, most of which were negative for previously described mutations in known USH genes upon primer extension-based microarray genotyping. We enriched the NGS template either by whole exome capture or by Long-PCR of the known USH genes. The main NGS sequencing platforms were used: SOLiD for whole exome sequencing, Illumina (Genome Analyzer II and Roche 454 (GS FLX for the Long-PCR sequencing. Long-PCR targeting was more efficient with up to 94% of USH gene regions displaying an overall coverage higher than 25×, whereas whole exome sequencing yielded a similar coverage for only 50% of those regions. Overall this integrated analysis led to the identification of 11 novel sequence variations in USH genes (2 homozygous and 9 heterozygous out of 18 detected. However, at least two cases were not genetically solved. Our result highlights the current limitations in the diagnostic use of NGS for USH patients. The limit for whole exome sequencing is linked to the need of a strong coverage and to the correct interpretation of sequence variations with a non obvious, pathogenic role, whereas the targeted approach suffers from the high genetic heterogeneity of USH that may be also caused by the presence of additional causative genes yet to be identified.

Molecular Diagnosis of Usher Syndrome: Application of Two Different Next Generation Sequencing-Based Procedures

Science.gov (United States)

Licastro, Danilo; Mutarelli, Margherita; Peluso, Ivana; Neveling, Kornelia; Wieskamp, Nienke; Rispoli, Rossella; Vozzi, Diego; Athanasakis, Emmanouil; D'Eustacchio, Angela; Pizzo, Mariateresa; D'Amico, Francesca; Ziviello, Carmela; Simonelli, Francesca; Fabretto, Antonella; Scheffer, Hans; Gasparini, Paolo; Banfi, Sandro; Nigro, Vincenzo

2012-01-01

Usher syndrome (USH) is a clinically and genetically heterogeneous disorder characterized by visual and hearing impairments. Clinically, it is subdivided into three subclasses with nine genes identified so far. In the present study, we investigated whether the currently available Next Generation Sequencing (NGS) technologies are already suitable for molecular diagnostics of USH. We analyzed a total of 12 patients, most of which were negative for previously described mutations in known USH genes upon primer extension-based microarray genotyping. We enriched the NGS template either by whole exome capture or by Long-PCR of the known USH genes. The main NGS sequencing platforms were used: SOLiD for whole exome sequencing, Illumina (Genome Analyzer II) and Roche 454 (GS FLX) for the Long-PCR sequencing. Long-PCR targeting was more efficient with up to 94% of USH gene regions displaying an overall coverage higher than 25×, whereas whole exome sequencing yielded a similar coverage for only 50% of those regions. Overall this integrated analysis led to the identification of 11 novel sequence variations in USH genes (2 homozygous and 9 heterozygous) out of 18 detected. However, at least two cases were not genetically solved. Our result highlights the current limitations in the diagnostic use of NGS for USH patients. The limit for whole exome sequencing is linked to the need of a strong coverage and to the correct interpretation of sequence variations with a non obvious, pathogenic role, whereas the targeted approach suffers from the high genetic heterogeneity of USH that may be also caused by the presence of additional causative genes yet to be identified. PMID:22952768

Complete genome sequence of a Chinese isolate of pepper vein yellows virus and evolutionary analysis based on the CP, MP and RdRp coding regions.

Science.gov (United States)

Liu, Maoyan; Liu, Xiangning; Li, Xun; Zhang, Deyong; Dai, Liangyin; Tang, Qianjun

2016-03-01

The genome sequence of pepper vein yellows virus (PeVYV) (PeVYV-HN, accession number KP326573), isolated from pepper plants (Capsicum annuum L.) grown at the Hunan Vegetables Institute (Changsha, Hunan, China), was determined by deep sequencing of small RNAs. The PeVYV-HN genome consists of 6244 nucleotides, contains six open reading frames (ORFs), and is similar to that of an isolate (AB594828) from Japan. Its genomic organization is similar to that of members of the genus Polerovirus. Sequence analysis revealed that PeVYV-HN shared 92% sequence identity with the Japanese PeVYV genome at both the nucleotide and amino acid levels. Evolutionary analysis based on the coat protein (CP), movement protein (MP), and RNA-dependent RNA polymerase (RdRP) showed that PeVYV could be divided into two major lineages corresponding to their geographical origins. The Asian isolates have a higher population expansion frequency than the African isolates. Negative selection and genetic drift (founder effect) were found to be the potential drivers of the molecular evolution of PeVYV. Moreover, recombination was not the distinct cause of PeVYV evolution. This is the first report of a complete genomic sequence of PeVYV in China.

Biomolecule Sequencer: Next-Generation DNA Sequencing Technology for In-Flight Environmental Monitoring, Research, and Beyond

Science.gov (United States)

Smith, David J.; Burton, Aaron; Castro-Wallace, Sarah; John, Kristen; Stahl, Sarah E.; Dworkin, Jason Peter; Lupisella, Mark L.

2016-01-01

On the International Space Station (ISS), technologies capable of rapid microbial identification and disease diagnostics are not currently available. NASA still relies upon sample return for comprehensive, molecular-based sample characterization. Next-generation DNA sequencing is a powerful approach for identifying microorganisms in air, water, and surfaces onboard spacecraft. The Biomolecule Sequencer payload, manifested to SpaceX-9 and scheduled on the Increment 4748 research plan (June 2016), will assess the functionality of a commercially-available next-generation DNA sequencer in the microgravity environment of ISS. The MinION device from Oxford Nanopore Technologies (Oxford, UK) measures picoamp changes in electrical current dependent on nucleotide sequences of the DNA strand migrating through nanopores in the system. The hardware is exceptionally small (9.5 x 3.2 x 1.6 cm), lightweight (120 grams), and powered only by a USB connection. For the ISS technology demonstration, the Biomolecule Sequencer will be powered by a Microsoft Surface Pro3. Ground-prepared samples containing lambda bacteriophage, Escherichia coli, and mouse genomic DNA, will be launched and stored frozen on the ISS until experiment initiation. Immediately prior to sequencing, a crew member will collect and thaw frozen DNA samples, connect the sequencer to the Surface Pro3, inject thawed samples into a MinION flow cell, and initiate sequencing. At the completion of the sequencing run, data will be downlinked for ground analysis. Identical, synchronous ground controls will be used for data comparisons to determine sequencer functionality, run-time sequence, current dynamics, and overall accuracy. We will present our latest results from the ISS flight experiment the first time DNA has ever been sequenced in space and discuss the many potential applications of the Biomolecule Sequencer for environmental monitoring, medical diagnostics, higher fidelity and more adaptable Space Biology Human

A Signal Processing Method to Explore Similarity in Protein Flexibility

Directory of Open Access Journals (Sweden)

Simina Vasilache

2010-01-01

Full Text Available Understanding mechanisms of protein flexibility is of great importance to structural biology. The ability to detect similarities between proteins and their patterns is vital in discovering new information about unknown protein functions. A Distance Constraint Model (DCM provides a means to generate a variety of flexibility measures based on a given protein structure. Although information about mechanical properties of flexibility is critical for understanding protein function for a given protein, the question of whether certain characteristics are shared across homologous proteins is difficult to assess. For a proper assessment, a quantified measure of similarity is necessary. This paper begins to explore image processing techniques to quantify similarities in signals and images that characterize protein flexibility. The dataset considered here consists of three different families of proteins, with three proteins in each family. The similarities and differences found within flexibility measures across homologous proteins do not align with sequence-based evolutionary methods.

Structural and sequence variants in patients with Silver-Russell syndrome or similar features-Curation of a disease database

DEFF Research Database (Denmark)

Tümer, Zeynep; López-Hernández, Julia Angélica; Netchine, Irène

2018-01-01

data of these patients. The clinical features are scored according to the Netchine-Harbison clinical scoring system (NH-CSS), which has recently been accepted as standard by consensus. The structural and sequence variations are reviewed and where necessary redescribed according to recent...

Towards predicting the encoding capability of MR fingerprinting sequences.

Science.gov (United States)

Sommer, K; Amthor, T; Doneva, M; Koken, P; Meineke, J; Börnert, P

2017-09-01

Sequence optimization and appropriate sequence selection is still an unmet need in magnetic resonance fingerprinting (MRF). The main challenge in MRF sequence design is the lack of an appropriate measure of the sequence's encoding capability. To find such a measure, three different candidates for judging the encoding capability have been investigated: local and global dot-product-based measures judging dictionary entry similarity as well as a Monte Carlo method that evaluates the noise propagation properties of an MRF sequence. Consistency of these measures for different sequence lengths as well as the capability to predict actual sequence performance in both phantom and in vivo measurements was analyzed. While the dot-product-based measures yielded inconsistent results for different sequence lengths, the Monte Carlo method was in a good agreement with phantom experiments. In particular, the Monte Carlo method could accurately predict the performance of different flip angle patterns in actual measurements. The proposed Monte Carlo method provides an appropriate measure of MRF sequence encoding capability and may be used for sequence optimization. Copyright © 2017 Elsevier Inc. All rights reserved.

Sequence similarity between the erythrocyte binding domain 1 of the Plasmodium vivax Duffy binding protein and the V3 loop of HIV-1 strain MN reveals binding residues for the Duffy Antigen Receptor for Chemokines

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Garry Robert F

2011-01-01

Full Text Available Abstract Background The surface glycoprotein (SU, gp120 of the human immunodeficiency virus (HIV must bind to a chemokine receptor, CCR5 or CXCR4, to invade CD4+ cells. Plasmodium vivax uses the Duffy Binding Protein (DBP to bind the Duffy Antigen Receptor for Chemokines (DARC and invade reticulocytes. Results Variable loop 3 (V3 of HIV-1 SU and domain 1 of the Plasmodium vivax DBP share a sequence similarity. The site of amino acid sequence similarity was necessary, but not sufficient, for DARC binding and contained a consensus heparin binding site essential for DARC binding. Both HIV-1 and P. vivax can be blocked from binding to their chemokine receptors by the chemokine, RANTES and its analog AOP-RANTES. Site directed mutagenesis of the heparin binding motif in members of the DBP family, the P. knowlesi alpha, beta and gamma proteins abrogated their binding to erythrocytes. Positively charged residues within domain 1 are required for binding of P. vivax and P. knowlesi erythrocyte binding proteins. Conclusion A heparin binding site motif in members of the DBP family may form part of a conserved erythrocyte receptor binding pocket.

Heuristics for multiobjective multiple sequence alignment.

Science.gov (United States)

Abbasi, Maryam; Paquete, Luís; Pereira, Francisco B

2016-07-15

Aligning multiple sequences arises in many tasks in Bioinformatics. However, the alignments produced by the current software packages are highly dependent on the parameters setting, such as the relative importance of opening gaps with respect to the increase of similarity. Choosing only one parameter setting may provide an undesirable bias in further steps of the analysis and give too simplistic interpretations. In this work, we reformulate multiple sequence alignment from a multiobjective point of view. The goal is to generate several sequence alignments that represent a trade-off between maximizing the substitution score and minimizing the number of indels/gaps in the sum-of-pairs score function. This trade-off gives to the practitioner further information about the similarity of the sequences, from which she could analyse and choose the most plausible alignment. We introduce several heuristic approaches, based on local search procedures, that compute a set of sequence alignments, which are representative of the trade-off between the two objectives (substitution score and indels). Several algorithm design options are discussed and analysed, with particular emphasis on the influence of the starting alignment and neighborhood search definitions on the overall performance. A perturbation technique is proposed to improve the local search, which provides a wide range of high-quality alignments. The proposed approach is tested experimentally on a wide range of instances. We performed several experiments with sequences obtained from the benchmark database BAliBASE 3.0. To evaluate the quality of the results, we calculate the hypervolume indicator of the set of score vectors returned by the algorithms. The results obtained allow us to identify reasonably good choices of parameters for our approach. Further, we compared our method in terms of correctly aligned pairs ratio and columns correctly aligned ratio with respect to reference alignments. Experimental results show

DNA sequence analysis of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T

OpenAIRE

Choudhary, M.; Kaplan, Samuel

2000-01-01

This paper describes the DNA sequence of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T. The photosynthesis gene cluster is located within a ~73 kb AseI genomic DNA fragment containing the puf, puhA, cycA and puc operons. A total of 65 open reading frames (ORFs) have been identified, of which 61 showed significant similarity to genes/proteins of other organisms while only four did not reveal any significant sequence similarity to any gene/protein sequences in the database. The da...

Amplification and chromosomal dispersion of human endogenous retroviral sequences

International Nuclear Information System (INIS)

Steele, P.E.; Martin, M.A.; Rabson, A.B.; Bryan, T.; O'Brien, S.J.

1986-01-01

Endogenous retroviral sequences have undergone amplification events involving both viral and flanking cellular sequences. The authors cloned members of an amplified family of full-length endogenous retroviral sequences. Genomic blotting, employing a flanking cellular DNA probe derived from a member of this family, revealed a similar array of reactive bands in both humans and chimpanzees, indicating that an amplification event involving retroviral and associated cellular DNA sequences occurred before the evolutionary separation of these two primates. Southern analyses of restricted somatic cell hybrid DNA preparations suggested that endogenous retroviral segments are widely dispersed in the human genome and that amplification and dispersion events may be linked

A Novel Hybrid Similarity Calculation Model

Directory of Open Access Journals (Sweden)

Xiaoping Fan

2017-01-01

Full Text Available This paper addresses the problems of similarity calculation in the traditional recommendation algorithms of nearest neighbor collaborative filtering, especially the failure in describing dynamic user preference. Proceeding from the perspective of solving the problem of user interest drift, a new hybrid similarity calculation model is proposed in this paper. This model consists of two parts, on the one hand the model uses the function fitting to describe users’ rating behaviors and their rating preferences, and on the other hand it employs the Random Forest algorithm to take user attribute features into account. Furthermore, the paper combines the two parts to build a new hybrid similarity calculation model for user recommendation. Experimental results show that, for data sets of different size, the model’s prediction precision is higher than the traditional recommendation algorithms.

Advanced Models and Algorithms for Self-Similar IP Network Traffic Simulation and Performance Analysis

Science.gov (United States)

Radev, Dimitar; Lokshina, Izabella

2010-11-01

The paper examines self-similar (or fractal) properties of real communication network traffic data over a wide range of time scales. These self-similar properties are very different from the properties of traditional models based on Poisson and Markov-modulated Poisson processes. Advanced fractal models of sequentional generators and fixed-length sequence generators, and efficient algorithms that are used to simulate self-similar behavior of IP network traffic data are developed and applied. Numerical examples are provided; and simulation results are obtained and analyzed.

Highly accurate fluorogenic DNA sequencing with information theory-based error correction.

Science.gov (United States)

Chen, Zitian; Zhou, Wenxiong; Qiao, Shuo; Kang, Li; Duan, Haifeng; Xie, X Sunney; Huang, Yanyi

2017-12-01

Eliminating errors in next-generation DNA sequencing has proved challenging. Here we present error-correction code (ECC) sequencing, a method to greatly improve sequencing accuracy by combining fluorogenic sequencing-by-synthesis (SBS) with an information theory-based error-correction algorithm. ECC embeds redundancy in sequencing reads by creating three orthogonal degenerate sequences, generated by alternate dual-base reactions. This is similar to encoding and decoding strategies that have proved effective in detecting and correcting errors in information communication and storage. We show that, when combined with a fluorogenic SBS chemistry with raw accuracy of 98.1%, ECC sequencing provides single-end, error-free sequences up to 200 bp. ECC approaches should enable accurate identification of extremely rare genomic variations in various applications in biology and medicine.

Digestive beta-glucosidases from the wood-feeding higher termite, Nasutitermes takasagoensis: intestinal distribution, molecular characterization, and alteration in sites of expression.

Science.gov (United States)

Tokuda, Gaku; Miyagi, Mio; Makiya, Hiromi; Watanabe, Hirofumi; Arakawa, Gaku

2009-12-01

beta-Glucosidase [EC 3.2.1.21] hydrolyzes cellobiose or cello-oligosaccharides into glucose during cellulose digestion in termites. SDS-PAGE and zymogram analyses of the digestive system in the higher termite Nasutitermes takasagoensis revealed that beta-glucosidase activity is localized in the salivary glands and midgut as dimeric glycoproteins. Degenerate PCR using primers based on the N-terminal amino acid sequences of the salivary beta-glucosidase resulted in cDNA fragments of 1.7 kb, encoding 489 amino acids with a sequence similar to glycosyl hydrolase family 1. Moreover, these primers amplified cDNA fragments from the midgut, and the deduced amino acid sequences are 87-91% identical to those of the salivary beta-glucosidases. Successful expression of the cDNAs in Escherichia coli implies that these sequences also encode functional beta-glucosidases. These results indicate that beta-glucosidases that primarily contribute to the digestive process of N. takasagoensis are produced in the midgut. Reverse transcription-PCR analysis indicated the site-specific expression of beta-glucosidase mRNAs in the salivary glands and midgut. These results suggest that termites have developed the ability to produce beta-glucosidases in the midgut, as is the case for endo-beta-1,4-glucanase, in which the site of expression has shifted from the salivary glands of lower termites to the midgut of higher termites. Copyright 2009 Elsevier Ltd. All rights reserved.

Evaluation of full S1 gene sequencing of classical and variant infectious bronchitis viruses extracted from allantoic fluid and FTA cards.

Science.gov (United States)

Manswr, Basim; Ball, Christopher; Forrester, Anne; Chantrey, Julian; Ganapathy, Kannan

2018-05-01

Sequence variability in the S1 gene determines the genotype of infectious bronchitis virus (IBV) strains. A single RT-PCR assay was developed to amplify and sequence the full S1 gene for six classical and variant IBVs (M41, D274, 793B, IS/885/00, IS/1494/06 and Q1) enriched in allantoic fluid (AF) or the same AF but inoculated onto Flinders Technology Association (FTA) cards. Representative strains from each genotype were grown in SPF eggs and RNA was extracted from AF. Full S1 gene amplification was achieved using primer A and primer 22.51. Products were sequenced using primer A, 1050+, 1380+ and SX3+ to obtain short sequences covering the full gene. Following serial dilutions of AF, detection limits of the partial assay were higher than those of the full S1 gene. Partial S1 sequences exhibited higher than average nucleotide similarity percentages (79%; 352bp) compared to full S1 sequences (77%; 1,756bp), suggesting that full S1 analysis allows greater strain differentiation. For IBV detection from AF inoculated FTA cards, four serotypes were incubated for up to 21 days at three temperatures; 4 o C, 24 o C and 40 o C. RNA was extracted and tested with partial and full S1 protocols. Through partial sequencing, all IBVs were successfully detected at all sampling points and storage temperatures. In contrast, using full S1 sequencing was not possible to amplify the gene beyond 14 days or when stored at 40°C. Data presented shows that for full S1 sequencing, a substantial amount of RNA is needed. Field samples collected onto FTA cards are unlikely to yield such quantity or quality.

Similarity of satellite DNA properties in the order Rodentia

Energy Technology Data Exchange (ETDEWEB)

Mazrimas, J A; Hatch, F T

1977-09-01

We have characterized satellite DNAs from 9 species of kangaroo rat (Dipodomys) and have shown that the HS-..cap alpha.. and HS-..beta.. satellites, where present, are nearly identical in all species as to melting transition midpoint (Tm), and density in neutral CsCl, alkaline CsCl, and Cs/sub 2/SO/sub 4/-Ag/sup +/ gradients. However, the MS satellites exist in two internally similar classes. The satellite DNAs from three other rodents were characterized (densities listed are in neutral CsCl). The pocket gopher, Thomomys bottae, contains Th-..cap alpha.. (1.713 g/ml) and Th-..beta.. (1.703 g/ml). The guinea pig (Cavia porcellus) contains Ca-..cap alpha.., Ca-..beta.., and Ca-..gamma.. at densities of 1.706 g/ml, 1.704 g/ml, and 1.704 g/ml, respectively. The antelope ground squirrel (Ammospermophilus harrisi) contains Am-..cap alpha.., 1.708 g/ml, Am-..beta.., 1.717 g/ml, and Am-..gamma.., 1.707 g/ml. The physical and chemical properties of the alpha-satellites from the above four rodents representing four different families in two suborders of Rodentia were compared. They show nearly identical Tm, nucleoside composition of single strands, and single strand densities in alkaline CsCl. Similar comparisons on the second or third satellite DNAs from these rodents also indicate a close relationship to each other. Thus the high degree of similarity of satellite sequences found in such a diverse group of rodents suggests a cellular function that is subject to natural selection, and implies that these sequences have been conserved over a considerable span of evolutionary time since the divergence of these rodents about 50 million years ago.

Similarity of satellite DNA properties in the order Rodentia

Energy Technology Data Exchange (ETDEWEB)

Mazrimas, J A; Hatch, F T

1977-09-01

Satellite DNAs from 9 species of kangaroo rat (Dipodomys) have been characterized and have shown that the HS-..cap alpha.. and HS-..beta.. satellites, where present, are nearly identical in all species as to melting transition midpoint (Tm), and density in neutral CsCl, alkaline CsCl, and Cs/sub 2/SO/sub 4/-Ag/sup +/ gradients. However, the MS satellites exist in two internally similar classes. The satellite DNAs from three other rodents were characterized (densities listed are in neutral CsCl). The pocket gopher, Thomomys bottae, contains Th-..cap alpha.. (1.713 g/ml) and Th..beta.. (1.703 g/ml). The guinea pig (Cavia porcellus) contains Ca-..cap alpha.., Ca-..beta.. and Ca-..gamma.. at densities of 1.706 g/ml, 1.704 g/ml and 1.704 g/ml, respectively. The antelope ground squirrel (Ammospermophilus harrisi) contains Am-..cap alpha.., 1.708 g/ml, Am-..beta.., 1.717 g/ml, and Am-..gamma.., 1.707 g/ml. The physical and chemical properties of the alpha-satellites from the above four rodents representing four different families in two suborders of Rodentia were compared. They show nearly identical Tm, nucleoside composition of single strands, and single strand densities in alkaline CsCl. Similar comparisons on the second or third satellite DNAs from these rodents also indicate a close relationship to each other. Thus the high degree of similarity of satellite sequences found in such a diverse group of rodents suggests a cellular function that is subject to natural selection, and implies that these sequences have been conserved over a considerable span of evolutionary time since the divergence of these rodents about 50 million years ago.

1H NMR studies of plastocyanin from Scenedesmus obliquus: Complete sequence-specific assignment, secondary structure analysis, and global fold

International Nuclear Information System (INIS)

Moore, J.M.; Chazin, W.J.; Wright, P.E.; Powls, R.

1988-01-01

Two-dimensional 1 H NMR methods have been used to make sequence-specific resonance assignments for the 97 amino acid residues of the plastocyanin from the green alga Scenedesmus obliquus. Assignments were obtained for all backbone protons and the majority of the side-chain protons. Spin system identification relied heavily on the observation of relayed connectivities to the backbone amide proton. Sequence-specific assignments were made by using the sequential assignment procedure. During this process, an extra valine residue was identified that had not been detected in the original amino acid sequence. Elements of regular secondary structure were identified from characteristic NOE connectivities between backbone protons, coupling constant values, and the observation of slowly exchanging amide protons. The protein in solution contains eight β-strands, one short segment of helix, five reverse turns, and five loops. The β-strands may be arranged into two βsheets on the basis of extensive cross-strand NOE connectivities. The chain-folding topology determined from the NMR experiments is that of a Greek key β-barrel and is similar to that observed for French bean plastocyanin in solution and poplar plastocyanin in the crystalline state. While the overall structures are similar, several differences in local structure between the S. obliquus and higher plant plastocyanins have been identified

The de Bono LAMS Sequence Series: Template Designs as Knowledge-Mobilising Strategy for 21st Century Higher Education

Science.gov (United States)

Dobozy, Eva

2012-01-01

In this paper, the five interlocking de Bono LAMS sequences are introduced as a new form of generic template designs. This transdisciplinary knowledge-mobilising strategy is based on Edward de Bono's attention-directing ideas and thinking skills, commonly known as the CoRT tools. The development of the de Bono LAMS sequence series is an important…

A tale of three next generation sequencing platforms: comparison of Ion Torrent, Pacific Biosciences and Illumina MiSeq sequencers

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Quail Michael A

2012-07-01

Full Text Available Abstract Background Next generation sequencing (NGS technology has revolutionized genomic and genetic research. The pace of change in this area is rapid with three major new sequencing platforms having been released in 2011: Ion Torrent’s PGM, Pacific Biosciences’ RS and the Illumina MiSeq. Here we compare the results obtained with those platforms to the performance of the Illumina HiSeq, the current market leader. In order to compare these platforms, and get sufficient coverage depth to allow meaningful analysis, we have sequenced a set of 4 microbial genomes with mean GC content ranging from 19.3 to 67.7%. Together, these represent a comprehensive range of genome content. Here we report our analysis of that sequence data in terms of coverage distribution, bias, GC distribution, variant detection and accuracy. Results Sequence generated by Ion Torrent, MiSeq and Pacific Biosciences technologies displays near perfect coverage behaviour on GC-rich, neutral and moderately AT-rich genomes, but a profound bias was observed upon sequencing the extremely AT-rich genome of Plasmodium falciparum on the PGM, resulting in no coverage for approximately 30% of the genome. We analysed the ability to call variants from each platform and found that we could call slightly more variants from Ion Torrent data compared to MiSeq data, but at the expense of a higher false positive rate. Variant calling from Pacific Biosciences data was possible but higher coverage depth was required. Context specific errors were observed in both PGM and MiSeq data, but not in that from the Pacific Biosciences platform. Conclusions All three fast turnaround sequencers evaluated here were able to generate usable sequence. However there are key differences between the quality of that data and the applications it will support.

Sequence Capture versus Restriction Site Associated DNA Sequencing for Shallow Systematics.

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Harvey, Michael G; Smith, Brian Tilston; Glenn, Travis C; Faircloth, Brant C; Brumfield, Robb T

2016-09-01

Sequence capture and restriction site associated DNA sequencing (RAD-Seq) are two genomic enrichment strategies for applying next-generation sequencing technologies to systematics studies. At shallow timescales, such as within species, RAD-Seq has been widely adopted among researchers, although there has been little discussion of the potential limitations and benefits of RAD-Seq and sequence capture. We discuss a series of issues that may impact the utility of sequence capture and RAD-Seq data for shallow systematics in non-model species. We review prior studies that used both methods, and investigate differences between the methods by re-analyzing existing RAD-Seq and sequence capture data sets from a Neotropical bird (Xenops minutus). We suggest that the strengths of RAD-Seq data sets for shallow systematics are the wide dispersion of markers across the genome, the relative ease and cost of laboratory work, the deep coverage and read overlap at recovered loci, and the high overall information that results. Sequence capture's benefits include flexibility and repeatability in the genomic regions targeted, success using low-quality samples, more straightforward read orthology assessment, and higher per-locus information content. The utility of a method in systematics, however, rests not only on its performance within a study, but on the comparability of data sets and inferences with those of prior work. In RAD-Seq data sets, comparability is compromised by low overlap of orthologous markers across species and the sensitivity of genetic diversity in a data set to an interaction between the level of natural heterozygosity in the samples examined and the parameters used for orthology assessment. In contrast, sequence capture of conserved genomic regions permits interrogation of the same loci across divergent species, which is preferable for maintaining comparability among data sets and studies for the purpose of drawing general conclusions about the impact of

DNA barcode data accurately assign higher spider taxa

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Jonathan A. Coddington

2016-07-01

Full Text Available The use of unique DNA sequences as a method for taxonomic identification is no longer fundamentally controversial, even though debate continues on the best markers, methods, and technology to use. Although both existing databanks such as GenBank and BOLD, as well as reference taxonomies, are imperfect, in best case scenarios “barcodes” (whether single or multiple, organelle or nuclear, loci clearly are an increasingly fast and inexpensive method of identification, especially as compared to manual identification of unknowns by increasingly rare expert taxonomists. Because most species on Earth are undescribed, a complete reference database at the species level is impractical in the near term. The question therefore arises whether unidentified species can, using DNA barcodes, be accurately assigned to more inclusive groups such as genera and families—taxonomic ranks of putatively monophyletic groups for which the global inventory is more complete and stable. We used a carefully chosen test library of CO1 sequences from 49 families, 313 genera, and 816 species of spiders to assess the accuracy of genus and family-level assignment. We used BLAST queries of each sequence against the entire library and got the top ten hits. The percent sequence identity was reported from these hits (PIdent, range 75–100%. Accurate assignment of higher taxa (PIdent above which errors totaled less than 5% occurred for genera at PIdent values >95 and families at PIdent values ≥ 91, suggesting these as heuristic thresholds for accurate generic and familial identifications in spiders. Accuracy of identification increases with numbers of species/genus and genera/family in the library; above five genera per family and fifteen species per genus all higher taxon assignments were correct. We propose that using percent sequence identity between conventional barcode sequences may be a feasible and reasonably accurate method to identify animals to family/genus. However

[Sequencing and analysis of the complete mitochondrial genome of the King Cobra, Ophiophagus hannah (Serpents: Elapidae)].

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Chen, Nian; Lai, Xiao-Ping

2010-07-01

We obtained the complete mitochondrial genome of King Cobra(GenBank accession number: EU_921899) by Ex Taq-PCR, TA-cloning and primer-walking methods. This genome is very similar to other vertebrate, which is 17 267 bp in length and encodes 38 genes (including 13 protein-coding, 2 ribosomal RNA and 23 transfer RNA genes) and two long non-coding regions. The duplication of tRNA-Ile gene forms a new mitochondrial gene rearrangement model. Eight tRNA genes and one protein genes were transcribed from L strand, and the other genes were transcribed genes from H strand. Genes on the H strand show a fairly similar content of Adenosine and Thymine respectively, whereas those on the L strand have higher proportion of A than T. Combined rDNA sequence data (12S+16S rRNA) were used to reconstruct the phylogeny of 21 snake species for which complete mitochondrial genome sequences were available in the public databases. This large data set and an appropriate range of outgroup taxa demonstrated that Elapidae is more closely related to colubridae than viperidae, which supports the traditional viewpoints.

Generation and analysis of expressed sequence tags from Botrytis cinerea

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EVELYN SILVA

2006-01-01

Full Text Available Botrytis cinerea is a filamentous plant pathogen of a wide range of plant species, and its infection may cause enormous damage both during plant growth and in the post-harvest phase. We have constructed a cDNA library from an isolate of B. cinerea and have sequenced 11,482 expressed sequence tags that were assembled into 1,003 contigs sequences and 3,032 singletons. Approximately 81% of the unigenes showed significant similarity to genes coding for proteins with known functions: more than 50% of the sequences code for genes involved in cellular metabolism, 12% for transport of metabolites, and approximately 10% for cellular organization. Other functional categories include responses to biotic and abiotic stimuli, cell communication, cell homeostasis, and cell development. We carried out pair-wise comparisons with fungal databases to determine the B. cinerea unisequence set with relevant similarity to genes in other fungal pathogenic counterparts. Among the 4,035 non-redundant B. cinerea unigenes, 1,338 (23% have significant homology with Fusarium verticillioides unigenes. Similar values were obtained for Saccharomyces cerevisiae and Aspergillus nidulans (22% and 24%, respectively. The lower percentages of homology were with Magnaporthe grisae and Neurospora crassa (13% and 19%, respectively. Several genes involved in putative and known fungal virulence and general pathogenicity were identified. The results provide important information for future research on this fungal pathogen

Self-similarities of periodic structures for a discrete model of a two-gene system

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Souza, S.L.T. de; Lima, A.A.; Caldas, I.L.; Medrano-T, R.O.; Guimarães-Filho, Z.O.

2012-01-01

We report self-similar properties of periodic structures remarkably organized in the two-parameter space for a two-gene system, described by two-dimensional symmetric map. The map consists of difference equations derived from the chemical reactions for gene expression and regulation. We characterize the system by using Lyapunov exponents and isoperiodic diagrams identifying periodic windows, denominated Arnold tongues and shrimp-shaped structures. Period-adding sequences are observed for both periodic windows. We also identify Fibonacci-type series and Golden ratio for Arnold tongues, and period multiple-of-three windows for shrimps. -- Highlights: ► The existence of noticeable periodic windows has been reported recently for several nonlinear systems. ► The periodic window distributions appear highly organized in two-parameter space. ► We characterize self-similar properties of Arnold tongues and shrimps for a two-gene model. ► We determine the period of the Arnold tongues recognizing a Fibonacci-type sequence. ► We explore self-similar features of the shrimps identifying multiple period-three structures.

Self-similarities of periodic structures for a discrete model of a two-gene system

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Souza, S.L.T. de, E-mail: thomaz@ufsj.edu.br [Departamento de Física e Matemática, Universidade Federal de São João del-Rei, Ouro Branco, MG (Brazil); Lima, A.A. [Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Caldas, I.L. [Instituto de Física, Universidade de São Paulo, São Paulo, SP (Brazil); Medrano-T, R.O. [Departamento de Ciências Exatas e da Terra, Universidade Federal de São Paulo, Diadema, SP (Brazil); Guimarães-Filho, Z.O. [Aix-Marseille Univ., CNRS PIIM UMR6633, International Institute for Fusion Science, Marseille (France)

2012-03-12

We report self-similar properties of periodic structures remarkably organized in the two-parameter space for a two-gene system, described by two-dimensional symmetric map. The map consists of difference equations derived from the chemical reactions for gene expression and regulation. We characterize the system by using Lyapunov exponents and isoperiodic diagrams identifying periodic windows, denominated Arnold tongues and shrimp-shaped structures. Period-adding sequences are observed for both periodic windows. We also identify Fibonacci-type series and Golden ratio for Arnold tongues, and period multiple-of-three windows for shrimps. -- Highlights: ► The existence of noticeable periodic windows has been reported recently for several nonlinear systems. ► The periodic window distributions appear highly organized in two-parameter space. ► We characterize self-similar properties of Arnold tongues and shrimps for a two-gene model. ► We determine the period of the Arnold tongues recognizing a Fibonacci-type sequence. ► We explore self-similar features of the shrimps identifying multiple period-three structures.

How Next-Generation Sequencing Has Aided Our Understanding of the Sequence Composition and Origin of B Chromosomes

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Alevtina Ruban

2017-10-01

Full Text Available Accessory, supernumerary, or—most simply—B chromosomes, are found in many eukaryotic karyotypes. These small chromosomes do not follow the usual pattern of segregation, but rather are transmitted in a higher than expected frequency. As increasingly being demonstrated by next-generation sequencing (NGS, their structure comprises fragments of standard (A chromosomes, although in some plant species, their sequence also includes contributions from organellar genomes. Transcriptomic analyses of various animal and plant species have revealed that, contrary to what used to be the common belief, some of the B chromosome DNA is protein-encoding. This review summarizes the progress in understanding B chromosome biology enabled by the application of next-generation sequencing technology and state-of-the-art bioinformatics. In particular, a contrast is drawn between a direct sequencing approach and a strategy based on a comparative genomics as alternative routes that can be taken towards the identification of B chromosome sequences.

First fungal genome sequence from Africa: A preliminary analysis

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Rene Sutherland

2012-01-01

Full Text Available Some of the most significant breakthroughs in the biological sciences this century will emerge from the development of next generation sequencing technologies. The ease of availability of DNA sequence made possible through these new technologies has given researchers opportunities to study organisms in a manner that was not possible with Sanger sequencing. Scientists will, therefore, need to embrace genomics, as well as develop and nurture the human capacity to sequence genomes and utilise the ’tsunami‘ of data that emerge from genome sequencing. In response to these challenges, we sequenced the genome of Fusarium circinatum, a fungal pathogen of pine that causes pitch canker, a disease of great concern to the South African forestry industry. The sequencing work was conducted in South Africa, making F. circinatum the first eukaryotic organism for which the complete genome has been sequenced locally. Here we report on the process that was followed to sequence, assemble and perform a preliminary characterisation of the genome. Furthermore, details of the computer annotation and manual curation of this genome are presented. The F. circinatum genome was found to be nearly 44 million bases in size, which is similar to that of four other Fusarium genomes that have been sequenced elsewhere. The genome contains just over 15 000 open reading frames, which is less than that of the related species, Fusarium oxysporum, but more than that for Fusarium verticillioides. Amongst the various putative gene clusters identified in F. circinatum, those encoding the secondary metabolites fumosin and fusarin appeared to harbour evidence of gene translocation. It is anticipated that similar comparisons of other loci will provide insights into the genetic basis for pathogenicity of the pitch canker pathogen. Perhaps more importantly, this project has engaged a relatively large group of scientists

QUASAR--scoring and ranking of sequence-structure alignments.

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Birzele, Fabian; Gewehr, Jan E; Zimmer, Ralf

2005-12-15

Sequence-structure alignments are a common means for protein structure prediction in the fields of fold recognition and homology modeling, and there is a broad variety of programs that provide such alignments based on sequence similarity, secondary structure or contact potentials. Nevertheless, finding the best sequence-structure alignment in a pool of alignments remains a difficult problem. QUASAR (quality of sequence-structure alignments ranking) provides a unifying framework for scoring sequence-structure alignments that aids finding well-performing combinations of well-known and custom-made scoring schemes. Those scoring functions can be benchmarked against widely accepted quality scores like MaxSub, TMScore, Touch and APDB, thus enabling users to test their own alignment scores against 'standard-of-truth' structure-based scores. Furthermore, individual score combinations can be optimized with respect to benchmark sets based on known structural relationships using QUASAR's in-built optimization routines.

Markov model plus k-word distributions: a synergy that produces novel statistical measures for sequence comparison.

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Dai, Qi; Yang, Yanchun; Wang, Tianming

2008-10-15

Many proposed statistical measures can efficiently compare biological sequences to further infer their structures, functions and evolutionary information. They are related in spirit because all the ideas for sequence comparison try to use the information on the k-word distributions, Markov model or both. Motivated by adding k-word distributions to Markov model directly, we investigated two novel statistical measures for sequence comparison, called wre.k.r and S2.k.r. The proposed measures were tested by similarity search, evaluation on functionally related regulatory sequences and phylogenetic analysis. This offers the systematic and quantitative experimental assessment of our measures. Moreover, we compared our achievements with these based on alignment or alignment-free. We grouped our experiments into two sets. The first one, performed via ROC (receiver operating curve) analysis, aims at assessing the intrinsic ability of our statistical measures to search for similar sequences from a database and discriminate functionally related regulatory sequences from unrelated sequences. The second one aims at assessing how well our statistical measure is used for phylogenetic analysis. The experimental assessment demonstrates that our similarity measures intending to incorporate k-word distributions into Markov model are more efficient.

Insights into the sequence parameters for halophilic adaptation.

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Nath, Abhigyan

2016-03-01

The sequence parameters for halophilic adaptation are still not fully understood. To understand the molecular basis of protein hypersaline adaptation, a detailed analysis is carried out, and investigated the likely association of protein sequence attributes to halophilic adaptation. A two-stage strategy is implemented, where in the first stage a supervised machine learning classifier is build, giving an overall accuracy of 86 % on stratified tenfold cross validation and 90 % on blind testing set, which are better than the previously reported results. The second stage consists of statistical analysis of sequence features and possible extraction of halophilic molecular signatures. The results of this study showed that, halophilic proteins are characterized by lower average charge, lower K content, and lower S content. A statistically significant preference/avoidance list of sequence parameters is also reported giving insights into the molecular basis of halophilic adaptation. D, Q, E, H, P, T, V are significantly preferred while N, C, I, K, M, F, S are significantly avoided. Among amino acid physicochemical groups, small, polar, charged, acidic and hydrophilic groups are preferred over other groups. The halophilic proteins also showed a preference for higher average flexibility, higher average polarity and avoidance for higher average positive charge, average bulkiness and average hydrophobicity. Some interesting trends observed in dipeptide counts are also reported. Further a systematic statistical comparison is undertaken for gaining insights into the sequence feature distribution in different residue structural states. The current analysis may facilitate the understanding of the mechanism of halophilic adaptation clearer, which can be further used for rational design of halophilic proteins.

Characterization of Erwinia amylovora strains from different host plants using repetitive-sequences PCR analysis, and restriction fragment length polymorphism and short-sequence DNA repeats of plasmid pEA29.

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Barionovi, D; Giorgi, S; Stoeger, A R; Ruppitsch, W; Scortichini, M

2006-05-01

The three main aims of the study were the assessment of the genetic relationship between a deviating Erwinia amylovora strain isolated from Amelanchier sp. (Maloideae) grown in Canada and other strains from Maloideae and Rosoideae, the investigation of the variability of the PstI fragment of the pEA29 plasmid using restriction fragment length polymorphism (RFLP) analysis and the determination of the number of short-sequence DNA repeats (SSR) by DNA sequence analysis in representative strains. Ninety-three strains obtained from 12 plant genera and different geographical locations were examined by repetitive-sequences PCR using Enterobacterial Repetitive Intergenic Consensus, BOX and Repetitive Extragenic Palindromic primer sets. Upon the unweighted pair group method with arithmetic mean analysis, a deviating strain from Amelanchier sp. was analysed using amplified ribosomal DNA restriction analysis (ARDRA) analysis and the sequencing of the 16S rDNA gene. This strain showed 99% similarity to other E. amylovora strains in the 16S gene and the same banding pattern with ARDRA. The RFLP analysis of pEA29 plasmid using MspI and Sau3A restriction enzymes showed a higher variability than that previously observed and no clear-cut grouping of the strains was possible. The number of SSR units reiterated two to 12 times. The strains obtained from pear orchards showing for the first time symptoms of fire blight had a low number of SSR units. The strains from Maloideae exhibit a wider genetic variability than previously thought. The RFLP analysis of a fragment of the pEA29 plasmid would not seem a reliable method for typing E. amylovora strains. A low number of SSR units was observed with first epidemics of fire blight. The current detection techniques are mainly based on the genetic similarities observed within the strains from the cultivated tree-fruit crops. For a more reliable detection of the fire blight pathogen also in wild and ornamentals Rosaceous plants the genetic

Recognition of HIV-1 peptides by host CTL is related to HIV-1 similarity to human proteins.

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Morgane Rolland

Full Text Available BACKGROUND: While human immunodeficiency virus type 1 (HIV-1-specific cytotoxic T lymphocytes preferentially target specific regions of the viral proteome, HIV-1 features that contribute to immune recognition are not well understood. One hypothesis is that similarities between HIV and human proteins influence the host immune response, i.e., resemblance between viral and host peptides could preclude reactivity against certain HIV epitopes. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the extent of similarity between HIV-1 and the human proteome. Proteins from the HIV-1 B consensus sequence from 2001 were dissected into overlapping k-mers, which were then probed against a non-redundant database of the human proteome in order to identify segments of high similarity. We tested the relationship between HIV-1 similarity to host encoded peptides and immune recognition in HIV-infected individuals, and found that HIV immunogenicity could be partially modulated by the sequence similarity to the host proteome. ELISpot responses to peptides spanning the entire viral proteome evaluated in 314 individuals showed a trend indicating an inverse relationship between the similarity to the host proteome and the frequency of recognition. In addition, analysis of responses by a group of 30 HIV-infected individuals against 944 overlapping peptides representing a broad range of individual HIV-1B Nef variants, affirmed that the degree of similarity to the host was significantly lower for peptides with reactive epitopes than for those that were not recognized. CONCLUSIONS/SIGNIFICANCE: Our results suggest that antigenic motifs that are scarcely represented in human proteins might represent more immunogenic CTL targets not selected against in the host. This observation could provide guidance in the design of more effective HIV immunogens, as sequences devoid of host-like features might afford superior immune reactivity.

Spatio-temporal alignment of pedobarographic image sequences.

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Oliveira, Francisco P M; Sousa, Andreia; Santos, Rubim; Tavares, João Manuel R S

2011-07-01

This article presents a methodology to align plantar pressure image sequences simultaneously in time and space. The spatial position and orientation of a foot in a sequence are changed to match the foot represented in a second sequence. Simultaneously with the spatial alignment, the temporal scale of the first sequence is transformed with the aim of synchronizing the two input footsteps. Consequently, the spatial correspondence of the foot regions along the sequences as well as the temporal synchronizing is automatically attained, making the study easier and more straightforward. In terms of spatial alignment, the methodology can use one of four possible geometric transformation models: rigid, similarity, affine, or projective. In the temporal alignment, a polynomial transformation up to the 4th degree can be adopted in order to model linear and curved time behaviors. Suitable geometric and temporal transformations are found by minimizing the mean squared error (MSE) between the input sequences. The methodology was tested on a set of real image sequences acquired from a common pedobarographic device. When used in experimental cases generated by applying geometric and temporal control transformations, the methodology revealed high accuracy. In addition, the intra-subject alignment tests from real plantar pressure image sequences showed that the curved temporal models produced better MSE results (P alignment of pedobarographic image data, since previous methods can only be applied on static images.

The role of heterologous chloroplast sequence elements in transgene integration and expression.

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Ruhlman, Tracey; Verma, Dheeraj; Samson, Nalapalli; Daniell, Henry

2010-04-01

Heterologous regulatory elements and flanking sequences have been used in chloroplast transformation of several crop species, but their roles and mechanisms have not yet been investigated. Nucleotide sequence identity in the photosystem II protein D1 (psbA) upstream region is 59% across all taxa; similar variation was consistent across all genes and taxa examined. Secondary structure and predicted Gibbs free energy values of the psbA 5' untranslated region (UTR) among different families reflected this variation. Therefore, chloroplast transformation vectors were made for tobacco (Nicotiana tabacum) and lettuce (Lactuca sativa), with endogenous (Nt-Nt, Ls-Ls) or heterologous (Nt-Ls, Ls-Nt) psbA promoter, 5' UTR and 3' UTR, regulating expression of the anthrax protective antigen (PA) or human proinsulin (Pins) fused with the cholera toxin B-subunit (CTB). Unique lettuce flanking sequences were completely eliminated during homologous recombination in the transplastomic tobacco genomes but not unique tobacco sequences. Nt-Ls or Ls-Nt transplastomic lines showed reduction of 80% PA and 97% CTB-Pins expression when compared with endogenous psbA regulatory elements, which accumulated up to 29.6% total soluble protein PA and 72.0% total leaf protein CTB-Pins, 2-fold higher than Rubisco. Transgene transcripts were reduced by 84% in Ls-Nt-CTB-Pins and by 72% in Nt-Ls-PA lines. Transcripts containing endogenous 5' UTR were stabilized in nonpolysomal fractions. Stromal RNA-binding proteins were preferentially associated with endogenous psbA 5' UTR. A rapid and reproducible regeneration system was developed for lettuce commercial cultivars by optimizing plant growth regulators. These findings underscore the need for sequencing complete crop chloroplast genomes, utilization of endogenous regulatory elements and flanking sequences, as well as optimization of plant growth regulators for efficient chloroplast transformation.

Structure, organization, and sequence of alpha satellite DNA from human chromosome 17: evidence for evolution by unequal crossing-over and an ancestral pentamer repeat shared with the human X chromosome.

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Waye, J S; Willard, H F

1986-09-01

The centromeric regions of all human chromosomes are characterized by distinct subsets of a diverse tandemly repeated DNA family, alpha satellite. On human chromosome 17, the predominant form of alpha satellite is a 2.7-kilobase-pair higher-order repeat unit consisting of 16 alphoid monomers. We present the complete nucleotide sequence of the 16-monomer repeat, which is present in 500 to 1,000 copies per chromosome 17, as well as that of a less abundant 15-monomer repeat, also from chromosome 17. These repeat units were approximately 98% identical in sequence, differing by the exclusion of precisely 1 monomer from the 15-monomer repeat. Homologous unequal crossing-over is suggested as a probable mechanism by which the different repeat lengths on chromosome 17 were generated, and the putative site of such a recombination event is identified. The monomer organization of the chromosome 17 higher-order repeat unit is based, in part, on tandemly repeated pentamers. A similar pentameric suborganization has been previously demonstrated for alpha satellite of the human X chromosome. Despite the organizational similarities, substantial sequence divergence distinguishes these subsets. Hybridization experiments indicate that the chromosome 17 and X subsets are more similar to each other than to the subsets found on several other human chromosomes. We suggest that the chromosome 17 and X alpha satellite subsets may be related components of a larger alphoid subfamily which have evolved from a common ancestral repeat into the contemporary chromosome-specific subsets.

Sequence characterization of cotton leaf curl virus from Rajasthan: phylogenetic relationship with other members of geminiviruses and detection of recombination.

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Kumar, A; Kumar, J; Khan, J A

2010-04-01

Diseased cotton plants showing typical leaf curl symptoms were collected from experimental plot of Agriculture Research Station-Sriganganagar, Rajasthan. Complete DNA-A component from samples taken from two areas were amplified through rolling circle amplification (RCA) using templiphi kit (GE Healthcare) and characterized. DNA-A of one isolate consists of 2751 nucleotides and second isolate of 2759 nucleotide. Both sequences comprised six ORF's. Genome organization of DNA-A of one isolate shows high sequence similarity with other characterized local begomovirus isolates of Rajasthan, while other isolate shows high sequence similarity with CLCuV reported from Pakistan. The maximum similarity of first isolate, CLCuV-SG01, shows highest sequence identity with Cotton leaf curl Abohar (Rajasthan) virus, and second isolate, CLCuV-SG02, shows highest sequence identity with cotton leaf curl virus from Pakistan. Both isolates showed 85% similarities with each other. The sequence data revealed probable infiltration of some strains of Cotton leaf curl virus from Pakistan to India, or co-existence of different isolates under similar geographical conditions. While CLCuV-SG01 shows highest nt sequence similarity with CLCuV Rajasthan (Abohar), nt identity of V1 ORF (encoding coat protein) of SG01 shows the highest nt identity (100%) with CLCuV Multan (Bhatinda) and Abohar virus while AC1 region also showed difference. Complete nucleotide sequence of SG01 shows only 86% similarity with CLCuV Multan virus. Similarity search revealed significant difference in AV1 and AC1 regions with respect to DNA-A suggesting an evolutionary history of recombination. Computer based analysis, recombination detection Program (RDP) supports the recombination hypothesis, indicated that recombination with other begomoviruses had taken place within V1 ORF and AC1 ORF of CLCuV-SG01 and AC1 ORF of CLCuV-SG02 and also in noncoding intergenic region (IR).

DELIMINATE--a fast and efficient method for loss-less compression of genomic sequences: sequence analysis.

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Mohammed, Monzoorul Haque; Dutta, Anirban; Bose, Tungadri; Chadaram, Sudha; Mande, Sharmila S

2012-10-01

An unprecedented quantity of genome sequence data is currently being generated using next-generation sequencing platforms. This has necessitated the development of novel bioinformatics approaches and algorithms that not only facilitate a meaningful analysis of these data but also aid in efficient compression, storage, retrieval and transmission of huge volumes of the generated data. We present a novel compression algorithm (DELIMINATE) that can rapidly compress genomic sequence data in a loss-less fashion. Validation results indicate relatively higher compression efficiency of DELIMINATE when compared with popular general purpose compression algorithms, namely, gzip, bzip2 and lzma. Linux, Windows and Mac implementations (both 32 and 64-bit) of DELIMINATE are freely available for download at: http://metagenomics.atc.tcs.com/compression/DELIMINATE. sharmila@atc.tcs.com Supplementary data are available at Bioinformatics online.

Gadobenate dimeglumine-enhanced MR of VX2 carcinoma in rabbit liver: usefulness of the delayed phase imaging and optimal pulse sequence

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Cho, Seung Il; Lee, Jeong Min; Kim, Young Kon; Kim, Chong Soo [College of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

2002-07-01

To assess the diagnostic value of delayed imaging using gadobenate dimeglumine (MultiHance) and to determine the optimal pulse sequence for the detection of VX2 carcinoma lesions in the rabbit. Twelve VX2 carcinomas implanted in the livers of eleven New Zealand rabbits were studied. All patients underwent an MR protocal consisting of precontrast T2-and T1-weighted sequences, followed by repetition of the T1-weighted sequence at 0 to 30 (arterial phase). 31-60 (portal phase), and 40 minutes (delayed phase) after the intravenous administration of 0.1 mmol/kg of gadobenate dimeglumine. The signal-to-noise ratio (SNR) of the liver and VX2 tumor, and the lesion-to-liver contrast-to-noise ratio (CNR) of precontrast and postcontrast MR images were quantitatively analyzed, and two experienced radiologists evaluated image quality in terms of lesion conspicuity, artifact, mass delineation, and vascular anatomy. Liver SNR was significantly higher at delayed imaging than at precontrast, arterial, and portal imaging (p<0.05), while lesion SNR was significantly higher at delayed imaging than at precontrast imaging (p<0.05). Lesion CNR was higher at delayed imaging than at precontrast and portal phase imaging (p<0.05), but there was no difference between arterial and delayed imaging. The latter provided better mass delineation than precontrast, arterial and portal phase imaging (p<0.05). While in terms of lesion conspicuity and vascular anatomy, the delayed phase was better than the arterial phase (p<0.05) but similar to the precontrast and portal phase. During the delayed phase, the gradient-echo sequence showed better results than the spin-echo in terms of liver SNR, and lesion SNR and CNR (p<0.05). Because it provides better lesion conspicuity and mass delineation by improving liver SNR and lesion-to-liver CNR, the addition of the delayed phase to a dynamic MRI sequence after gadobenate dimeglumine adminstration facilitates lesion detection. For delayed-phase imaging, the

Gadobenate dimeglumine-enhanced MR of VX2 carcinoma in rabbit liver: usefulness of the delayed phase imaging and optimal pulse sequence

International Nuclear Information System (INIS)

Cho, Seung Il; Lee, Jeong Min; Kim, Young Kon; Kim, Chong Soo

2002-01-01

To assess the diagnostic value of delayed imaging using gadobenate dimeglumine (MultiHance) and to determine the optimal pulse sequence for the detection of VX2 carcinoma lesions in the rabbit. Twelve VX2 carcinomas implanted in the livers of eleven New Zealand rabbits were studied. All patients underwent an MR protocal consisting of precontrast T2-and T1-weighted sequences, followed by repetition of the T1-weighted sequence at 0 to 30 (arterial phase). 31-60 (portal phase), and 40 minutes (delayed phase) after the intravenous administration of 0.1 mmol/kg of gadobenate dimeglumine. The signal-to-noise ratio (SNR) of the liver and VX2 tumor, and the lesion-to-liver contrast-to-noise ratio (CNR) of precontrast and postcontrast MR images were quantitatively analyzed, and two experienced radiologists evaluated image quality in terms of lesion conspicuity, artifact, mass delineation, and vascular anatomy. Liver SNR was significantly higher at delayed imaging than at precontrast, arterial, and portal imaging (p<0.05), while lesion SNR was significantly higher at delayed imaging than at precontrast imaging (p<0.05). Lesion CNR was higher at delayed imaging than at precontrast and portal phase imaging (p<0.05), but there was no difference between arterial and delayed imaging. The latter provided better mass delineation than precontrast, arterial and portal phase imaging (p<0.05). While in terms of lesion conspicuity and vascular anatomy, the delayed phase was better than the arterial phase (p<0.05) but similar to the precontrast and portal phase. During the delayed phase, the gradient-echo sequence showed better results than the spin-echo in terms of liver SNR, and lesion SNR and CNR (p<0.05). Because it provides better lesion conspicuity and mass delineation by improving liver SNR and lesion-to-liver CNR, the addition of the delayed phase to a dynamic MRI sequence after gadobenate dimeglumine adminstration facilitates lesion detection. For delayed-phase imaging, the

Chaos game representation (CGR)-walk model for DNA sequences

International Nuclear Information System (INIS)

Jie, Gao; Zhen-Yuan, Xu

2009-01-01

Chaos game representation (CGR) is an iterative mapping technique that processes sequences of units, such as nucleotides in a DNA sequence or amino acids in a protein, in order to determine the coordinates of their positions in a continuous space. This distribution of positions has two features: one is unique, and the other is source sequence that can be recovered from the coordinates so that the distance between positions may serve as a measure of similarity between the corresponding sequences. A CGR-walk model is proposed based on CGR coordinates for the DNA sequences. The CGR coordinates are converted into a time series, and a long-memory ARFIMA (p, d, q) model, where ARFIMA stands for autoregressive fractionally integrated moving average, is introduced into the DNA sequence analysis. This model is applied to simulating real CGR-walk sequence data of ten genomic sequences. Remarkably long-range correlations are uncovered in the data, and the results from these models are reasonably fitted with those from the ARFIMA (p, d, q) model. (cross-disciplinary physics and related areas of science and technology)

Aftereffects of Spectrally Similar and Dissimilar Spectral Motion Adaptors in the Tritone Paradox

Directory of Open Access Journals (Sweden)

Stephanie Malek

2018-05-01

Full Text Available Shepard tones consist of octave-spaced components, whose amplitudes are generated under a fixed bell-shaped spectral envelope. They are well defined in pitch chroma, but generate octave confusions that in turn can produce ambiguities in the perceived relative pitch heights when their chromas are exactly a tritone apart (the tritone paradox. This study examined the effects of tonal context on relative pitch height judgments using adaptor sequences followed by target sequences (pairs of Shepard tones of different chromas separated by a tritone. Listeners judged whether the second target Shepard tone was higher or lower than the first. Adaptor sequences consisted of rising or falling scales (43 s at the beginning of each block, 4 s before each target sequence. Two sets of Shepard tones were used for adaptors and targets that were generated under spectral envelopes centered at either A3 (220 Hz and C6 (1,046 Hz. Pitch direction judgments (rising vs. falling to spectrally consistent (A3–A3, C6–C6 and inconsistent (A3–C6, C6–A3 adaptor-target combinations were studied. Large significant contrastive aftereffects (0.08–0.21 change in fraction of pitch direction responses were only found for the Shepard tones that were judged as higher in the control condition (judgments about the target sequences without adaptor sequences for the consistent adaptor-target conditions (A3–A3, C6–C6. The experiments rule out explanations based on non-sensory decision making processes. Possible explanations in terms of perceptual aftereffects caused by adaptation in central auditory frequency-motion detectors are discussed.

Recalling visual serial order for verbal sequences

NARCIS (Netherlands)

Logie, R.H.; Saito, S.; Morita, A.; Varma, S.; Norris, D.

2016-01-01

We report three experiments in which participants performed written serial recall of visually presented verbal sequences with items varying in visual similarity. In Experiments 1 and 2 native speakers of Japanese recalled visually presented Japanese Kanji characters. In Experiment 3, native speakers

Transcriptome sequencing of the Microarray Quality Control (MAQC RNA reference samples using next generation sequencing

Directory of Open Access Journals (Sweden)

Thierry-Mieg Danielle

2009-06-01

Full Text Available Abstract Background Transcriptome sequencing using next-generation sequencing platforms will soon be competing with DNA microarray technologies for global gene expression analysis. As a preliminary evaluation of these promising technologies, we performed deep sequencing of cDNA synthesized from the Microarray Quality Control (MAQC reference RNA samples using Roche's 454 Genome Sequencer FLX. Results We generated more that 3.6 million sequence reads of average length 250 bp for the MAQC A and B samples and introduced a data analysis pipeline for translating cDNA read counts into gene expression levels. Using BLAST, 90% of the reads mapped to the human genome and 64% of the reads mapped to the RefSeq database of well annotated genes with e-values ≤ 10-20. We measured gene expression levels in the A and B samples by counting the numbers of reads that mapped to individual RefSeq genes in multiple sequencing runs to evaluate the MAQC quality metrics for reproducibility, sensitivity, specificity, and accuracy and compared the results with DNA microarrays and Quantitative RT-PCR (QRTPCR from the MAQC studies. In addition, 88% of the reads were successfully aligned directly to the human genome using the AceView alignment programs with an average 90% sequence similarity to identify 137,899 unique exon junctions, including 22,193 new exon junctions not yet contained in the RefSeq database. Conclusion Using the MAQC metrics for evaluating the performance of gene expression platforms, the ExpressSeq results for gene expression levels showed excellent reproducibility, sensitivity, and specificity that improved systematically with increasing shotgun sequencing depth, and quantitative accuracy that was comparable to DNA microarrays and QRTPCR. In addition, a careful mapping of the reads to the genome using the AceView alignment programs shed new light on the complexity of the human transcriptome including the discovery of thousands of new splice variants.

Enhanced throughput for infrared automated DNA sequencing

Science.gov (United States)

Middendorf, Lyle R.; Gartside, Bill O.; Humphrey, Pat G.; Roemer, Stephen C.; Sorensen, David R.; Steffens, David L.; Sutter, Scott L.

1995-04-01

Several enhancements have been developed and applied to infrared automated DNA sequencing resulting in significantly higher throughput. A 41 cm sequencing gel (31 cm well- to-read distance) combines high resolution of DNA sequencing fragments with optimized run times yielding two runs per day of 500 bases per sample. A 66 cm sequencing gel (56 cm well-to-read distance) produces sequence read lengths of up to 1000 bases for ds and ss templates using either T7 polymerase or cycle-sequencing protocols. Using a multichannel syringe to load 64 lanes allows 16 samples (compatible with 96-well format) to be visualized for each run. The 41 cm gel configuration allows 16,000 bases per day (16 samples X 500 bases/sample X 2 ten hour runs/day) to be sequenced with the advantages of infrared technology. Enhancements to internal labeling techniques using an infrared-labeled dATP molecule (Boehringer Mannheim GmbH, Penzberg, Germany; Sequenase (U.S. Biochemical) have also been made. The inclusion of glycerol in the sequencing reactions yields greatly improved results for some primer and template combinations. The inclusion of (alpha) -Thio-dNTP's in the labeling reaction increases signal intensity two- to three-fold.

Investigations on the two-dimensional aperiodic plasma photonic crystals with fractal Fibonacci sequence

Directory of Open Access Journals (Sweden)

Hai-Feng Zhang

2017-07-01

Full Text Available In this paper, the properties of photonic band gaps (PBGs and defect modes of two-dimensional (2D fractal plasma photonic crystals (PPCs under a transverse-magnetic (TM wave are theoretically investigated by a modified plane wave expansion (PWE method. The configuration of 2D PPCs is the square lattices with the iteration rule of the Fibonacci sequence whose constituents are homogeneous and isotropic. The proposed 2D PPCs is filled with the dielectric cylinders in the plasma background. The accuracy and convergence of the present modified PWE method also are validated by a numerical example. The calculated results illustrate that the enough accuracy and good convergence can be achieved compared to the conventional PWE method, if the number of meshed grids is large enough. The dispersion curves of the proposed PPCs and 2D PPCs with a conventional square lattice are theoretically computed to study the properties of PBGs and defect modes. The simulated results demonstrate that the advantaged properties can be obtained in the proposed PPCs compared to the 2D conventional PPCs with similar lattices. If the Fibonacci sequence is introduced into the 2D PPCs, the larger PBGs and higher cutoff frequency can be achieved. The lower edges of PBGs are flat, which are originated from the Mie resonances. The defect modes can be considered as the quasi-localized states since the Fibonacci sequence has the self-similarity and non-periodicity at the same time. The effects of configurational parameters on the characters of the present PPCs are investigated. The results show that the PBGs and defect modes can be easily manipulated by tuning those parameters.

The Bryopsis hypnoides plastid genome: multimeric forms and complete nucleotide sequence.

Directory of Open Access Journals (Sweden)

Fang Lü

Full Text Available BACKGROUND: Bryopsis hypnoides Lamouroux is a siphonous green alga, and its extruded protoplasm can aggregate spontaneously in seawater and develop into mature individuals. The chloroplast of B. hypnoides is the biggest organelle in the cell and shows strong autonomy. To better understand this organelle, we sequenced and analyzed the chloroplast genome of this green alga. PRINCIPAL FINDINGS: A total of 111 functional genes, including 69 potential protein-coding genes, 5 ribosomal RNA genes, and 37 tRNA genes were identified. The genome size (153,429 bp, arrangement, and inverted-repeat (IR-lacking structure of the B. hypnoides chloroplast DNA (cpDNA closely resembles that of Chlorella vulgaris. Furthermore, our cytogenomic investigations using pulsed-field gel electrophoresis (PFGE and southern blotting methods showed that the B. hypnoides cpDNA had multimeric forms, including monomer, dimer, trimer, tetramer, and even higher multimers, which is similar to the higher order organization observed previously for higher plant cpDNA. The relative amounts of the four multimeric cpDNA forms were estimated to be about 1, 1/2, 1/4, and 1/8 based on molecular hybridization analysis. Phylogenetic analyses based on a concatenated alignment of chloroplast protein sequences suggested that B. hypnoides is sister to all Chlorophyceae and this placement received moderate support. CONCLUSION: All of the results suggest that the autonomy of the chloroplasts of B. hypnoides has little to do with the size and gene content of the cpDNA, and the IR-lacking structure of the chloroplasts indirectly demonstrated that the multimeric molecules might result from the random cleavage and fusion of replication intermediates instead of recombinational events.

Human Chromosome 7: DNA Sequence and Biology

OpenAIRE

Scherer, Stephen W.; Cheung, Joseph; MacDonald, Jeffrey R.; Osborne, Lucy R.; Nakabayashi, Kazuhiko; Herbrick, Jo-Anne; Carson, Andrew R.; Parker-Katiraee, Layla; Skaug, Jennifer; Khaja, Razi; Zhang, Junjun; Hudek, Alexander K.; Li, Martin; Haddad, May; Duggan, Gavin E.

2003-01-01

DNA sequence and annotation of the entire human chromosome 7, encompassing nearly 158 million nucleotides of DNA and 1917 gene structures, are presented. To generate a higher order description, additional structural features such as imprinted genes, fragile sites, and segmental duplications were integrated at the level of the DNA sequence with medical genetic data, including 440 chromosome rearrangement breakpoints associated with disease. This approach enabled the discovery of candidate gene...

A robust and accurate binning algorithm for metagenomic sequences with arbitrary species abundance ratio.

Science.gov (United States)

Leung, Henry C M; Yiu, S M; Yang, Bin; Peng, Yu; Wang, Yi; Liu, Zhihua; Chen, Jingchi; Qin, Junjie; Li, Ruiqiang; Chin, Francis Y L

2011-06-01

With the rapid development of next-generation sequencing techniques, metagenomics, also known as environmental genomics, has emerged as an exciting research area that enables us to analyze the microbial environment in which we live. An important step for metagenomic data analysis is the identification and taxonomic characterization of DNA fragments (reads or contigs) resulting from sequencing a sample of mixed species. This step is referred to as 'binning'. Binning algorithms that are based on sequence similarity and sequence composition markers rely heavily on the reference genomes of known microorganisms or phylogenetic markers. Due to the limited availability of reference genomes and the bias and low availability of markers, these algorithms may not be applicable in all cases. Unsupervised binning algorithms which can handle fragments from unknown species provide an alternative approach. However, existing unsupervised binning algorithms only work on datasets either with balanced species abundance ratios or rather different abundance ratios, but not both. In this article, we present MetaCluster 3.0, an integrated binning method based on the unsupervised top--down separation and bottom--up merging strategy, which can bin metagenomic fragments of species with very balanced abundance ratios (say 1:1) to very different abundance ratios (e.g. 1:24) with consistently higher accuracy than existing methods. MetaCluster 3.0 can be downloaded at http://i.cs.hku.hk/~alse/MetaCluster/.

Whole-Exome Sequencing Identifies Rare and Low-Frequency Coding Variants Associated with LDL Cholesterol

Science.gov (United States)

Lange, Leslie A.; Hu, Youna; Zhang, He; Xue, Chenyi; Schmidt, Ellen M.; Tang, Zheng-Zheng; Bizon, Chris; Lange, Ethan M.; Smith, Joshua D.; Turner, Emily H.; Jun, Goo; Kang, Hyun Min; Peloso, Gina; Auer, Paul; Li, Kuo-ping; Flannick, Jason; Zhang, Ji; Fuchsberger, Christian; Gaulton, Kyle; Lindgren, Cecilia; Locke, Adam; Manning, Alisa; Sim, Xueling; Rivas, Manuel A.; Holmen, Oddgeir L.; Gottesman, Omri; Lu, Yingchang; Ruderfer, Douglas; Stahl, Eli A.; Duan, Qing; Li, Yun; Durda, Peter; Jiao, Shuo; Isaacs, Aaron; Hofman, Albert; Bis, Joshua C.; Correa, Adolfo; Griswold, Michael E.; Jakobsdottir, Johanna; Smith, Albert V.; Schreiner, Pamela J.; Feitosa, Mary F.; Zhang, Qunyuan; Huffman, Jennifer E.; Crosby, Jacy; Wassel, Christina L.; Do, Ron; Franceschini, Nora; Martin, Lisa W.; Robinson, Jennifer G.; Assimes, Themistocles L.; Crosslin, David R.; Rosenthal, Elisabeth A.; Tsai, Michael; Rieder, Mark J.; Farlow, Deborah N.; Folsom, Aaron R.; Lumley, Thomas; Fox, Ervin R.; Carlson, Christopher S.; Peters, Ulrike; Jackson, Rebecca D.; van Duijn, Cornelia M.; Uitterlinden, André G.; Levy, Daniel; Rotter, Jerome I.; Taylor, Herman A.; Gudnason, Vilmundur; Siscovick, David S.; Fornage, Myriam; Borecki, Ingrid B.; Hayward, Caroline; Rudan, Igor; Chen, Y. Eugene; Bottinger, Erwin P.; Loos, Ruth J.F.; Sætrom, Pål; Hveem, Kristian; Boehnke, Michael; Groop, Leif; McCarthy, Mark; Meitinger, Thomas; Ballantyne, Christie M.; Gabriel, Stacey B.; O’Donnell, Christopher J.; Post, Wendy S.; North, Kari E.; Reiner, Alexander P.; Boerwinkle, Eric; Psaty, Bruce M.; Altshuler, David; Kathiresan, Sekar; Lin, Dan-Yu; Jarvik, Gail P.; Cupples, L. Adrienne; Kooperberg, Charles; Wilson, James G.; Nickerson, Deborah A.; Abecasis, Goncalo R.; Rich, Stephen S.; Tracy, Russell P.; Willer, Cristen J.; Gabriel, Stacey B.; Altshuler, David M.; Abecasis, Gonçalo R.; Allayee, Hooman; Cresci, Sharon; Daly, Mark J.; de Bakker, Paul I.W.; DePristo, Mark A.; Do, Ron; Donnelly, Peter; Farlow, Deborah N.; Fennell, Tim; Garimella, Kiran; Hazen, Stanley L.; Hu, Youna; Jordan, Daniel M.; Jun, Goo; Kathiresan, Sekar; Kang, Hyun Min; Kiezun, Adam; Lettre, Guillaume; Li, Bingshan; Li, Mingyao; Newton-Cheh, Christopher H.; Padmanabhan, Sandosh; Peloso, Gina; Pulit, Sara; Rader, Daniel J.; Reich, David; Reilly, Muredach P.; Rivas, Manuel A.; Schwartz, Steve; Scott, Laura; Siscovick, David S.; Spertus, John A.; Stitziel, Nathaniel O.; Stoletzki, Nina; Sunyaev, Shamil R.; Voight, Benjamin F.; Willer, Cristen J.; Rich, Stephen S.; Akylbekova, Ermeg; Atwood, Larry D.; Ballantyne, Christie M.; Barbalic, Maja; Barr, R. Graham; Benjamin, Emelia J.; Bis, Joshua; Boerwinkle, Eric; Bowden, Donald W.; Brody, Jennifer; Budoff, Matthew; Burke, Greg; Buxbaum, Sarah; Carr, Jeff; Chen, Donna T.; Chen, Ida Y.; Chen, Wei-Min; Concannon, Pat; Crosby, Jacy; Cupples, L. Adrienne; D’Agostino, Ralph; DeStefano, Anita L.; Dreisbach, Albert; Dupuis, Josée; Durda, J. Peter; Ellis, Jaclyn; Folsom, Aaron R.; Fornage, Myriam; Fox, Caroline S.; Fox, Ervin; Funari, Vincent; Ganesh, Santhi K.; Gardin, Julius; Goff, David; Gordon, Ora; Grody, Wayne; Gross, Myron; Guo, Xiuqing; Hall, Ira M.; Heard-Costa, Nancy L.; Heckbert, Susan R.; Heintz, Nicholas; Herrington, David M.; Hickson, DeMarc; Huang, Jie; Hwang, Shih-Jen; Jacobs, David R.; Jenny, Nancy S.; Johnson, Andrew D.; Johnson, Craig W.; Kawut, Steven; Kronmal, Richard; Kurz, Raluca; Lange, Ethan M.; Lange, Leslie A.; Larson, Martin G.; Lawson, Mark; Lewis, Cora E.; Levy, Daniel; Li, Dalin; Lin, Honghuang; Liu, Chunyu; Liu, Jiankang; Liu, Kiang; Liu, Xiaoming; Liu, Yongmei; Longstreth, William T.; Loria, Cay; Lumley, Thomas; Lunetta, Kathryn; Mackey, Aaron J.; Mackey, Rachel; Manichaikul, Ani; Maxwell, Taylor; McKnight, Barbara; Meigs, James B.; Morrison, Alanna C.; Musani, Solomon K.; Mychaleckyj, Josyf C.; Nettleton, Jennifer A.; North, Kari; O’Donnell, Christopher J.; O’Leary, Daniel; Ong, Frank; Palmas, Walter; Pankow, James S.; Pankratz, Nathan D.; Paul, Shom; Perez, Marco; Person, Sharina D.; Polak, Joseph; Post, Wendy S.; Psaty, Bruce M.; Quinlan, Aaron R.; Raffel, Leslie J.; Ramachandran, Vasan S.; Reiner, Alexander P.; Rice, Kenneth; Rotter, Jerome I.; Sanders, Jill P.; Schreiner, Pamela; Seshadri, Sudha; Shea, Steve; Sidney, Stephen; Silverstein, Kevin; Smith, Nicholas L.; Sotoodehnia, Nona; Srinivasan, Asoke; Taylor, Herman A.; Taylor, Kent; Thomas, Fridtjof; Tracy, Russell P.; Tsai, Michael Y.; Volcik, Kelly A.; Wassel, Chrstina L.; Watson, Karol; Wei, Gina; White, Wendy; Wiggins, Kerri L.; Wilk, Jemma B.; Williams, O. Dale; Wilson, Gregory; Wilson, James G.; Wolf, Phillip; Zakai, Neil A.; Hardy, John; Meschia, James F.; Nalls, Michael; Singleton, Andrew; Worrall, Brad; Bamshad, Michael J.; Barnes, Kathleen C.; Abdulhamid, Ibrahim; Accurso, Frank; Anbar, Ran; Beaty, Terri; Bigham, Abigail; Black, Phillip; Bleecker, Eugene; Buckingham, Kati; Cairns, Anne Marie; Caplan, Daniel; Chatfield, Barbara; Chidekel, Aaron; Cho, Michael; Christiani, David C.; Crapo, James D.; Crouch, Julia; Daley, Denise; Dang, Anthony; Dang, Hong; De Paula, Alicia; DeCelie-Germana, Joan; Drumm, Allen DozorMitch; Dyson, Maynard; Emerson, Julia; Emond, Mary J.; Ferkol, Thomas; Fink, Robert; Foster, Cassandra; Froh, Deborah; Gao, Li; Gershan, William; Gibson, Ronald L.; Godwin, Elizabeth; Gondor, Magdalen; Gutierrez, Hector; Hansel, Nadia N.; Hassoun, Paul M.; Hiatt, Peter; Hokanson, John E.; Howenstine, Michelle; Hummer, Laura K.; Kanga, Jamshed; Kim, Yoonhee; Knowles, Michael R.; Konstan, Michael; Lahiri, Thomas; Laird, Nan; Lange, Christoph; Lin, Lin; Lin, Xihong; Louie, Tin L.; Lynch, David; Make, Barry; Martin, Thomas R.; Mathai, Steve C.; Mathias, Rasika A.; McNamara, John; McNamara, Sharon; Meyers, Deborah; Millard, Susan; Mogayzel, Peter; Moss, Richard; Murray, Tanda; Nielson, Dennis; Noyes, Blakeslee; O’Neal, Wanda; Orenstein, David; O’Sullivan, Brian; Pace, Rhonda; Pare, Peter; Parker, H. Worth; Passero, Mary Ann; Perkett, Elizabeth; Prestridge, Adrienne; Rafaels, Nicholas M.; Ramsey, Bonnie; Regan, Elizabeth; Ren, Clement; Retsch-Bogart, George; Rock, Michael; Rosen, Antony; Rosenfeld, Margaret; Ruczinski, Ingo; Sanford, Andrew; Schaeffer, David; Sell, Cindy; Sheehan, Daniel; Silverman, Edwin K.; Sin, Don; Spencer, Terry; Stonebraker, Jackie; Tabor, Holly K.; Varlotta, Laurie; Vergara, Candelaria I.; Weiss, Robert; Wigley, Fred; Wise, Robert A.; Wright, Fred A.; Wurfel, Mark M.; Zanni, Robert; Zou, Fei; Nickerson, Deborah A.; Rieder, Mark J.; Green, Phil; Shendure, Jay; Akey, Joshua M.; Bustamante, Carlos D.; Crosslin, David R.; Eichler, Evan E.; Fox, P. Keolu; Fu, Wenqing; Gordon, Adam; Gravel, Simon; Jarvik, Gail P.; Johnsen, Jill M.; Kan, Mengyuan; Kenny, Eimear E.; Kidd, Jeffrey M.; Lara-Garduno, Fremiet; Leal, Suzanne M.; Liu, Dajiang J.; McGee, Sean; O’Connor, Timothy D.; Paeper, Bryan; Robertson, Peggy D.; Smith, Joshua D.; Staples, Jeffrey C.; Tennessen, Jacob A.; Turner, Emily H.; Wang, Gao; Yi, Qian; Jackson, Rebecca; Peters, Ulrike; Carlson, Christopher S.; Anderson, Garnet; Anton-Culver, Hoda; Assimes, Themistocles L.; Auer, Paul L.; Beresford, Shirley; Bizon, Chris; Black, Henry; Brunner, Robert; Brzyski, Robert; Burwen, Dale; Caan, Bette; Carty, Cara L.; Chlebowski, Rowan; Cummings, Steven; Curb, J. David; Eaton, Charles B.; Ford, Leslie; Franceschini, Nora; Fullerton, Stephanie M.; Gass, Margery; Geller, Nancy; Heiss, Gerardo; Howard, Barbara V.; Hsu, Li; Hutter, Carolyn M.; Ioannidis, John; Jiao, Shuo; Johnson, Karen C.; Kooperberg, Charles; Kuller, Lewis; LaCroix, Andrea; Lakshminarayan, Kamakshi; Lane, Dorothy; Lasser, Norman; LeBlanc, Erin; Li, Kuo-Ping; Limacher, Marian; Lin, Dan-Yu; Logsdon, Benjamin A.; Ludlam, Shari; Manson, JoAnn E.; Margolis, Karen; Martin, Lisa; McGowan, Joan; Monda, Keri L.; Kotchen, Jane Morley; Nathan, Lauren; Ockene, Judith; O’Sullivan, Mary Jo; Phillips, Lawrence S.; Prentice, Ross L.; Robbins, John; Robinson, Jennifer G.; Rossouw, Jacques E.; Sangi-Haghpeykar, Haleh; Sarto, Gloria E.; Shumaker, Sally; Simon, Michael S.; Stefanick, Marcia L.; Stein, Evan; Tang, Hua; Taylor, Kira C.; Thomson, Cynthia A.; Thornton, Timothy A.; Van Horn, Linda; Vitolins, Mara; Wactawski-Wende, Jean; Wallace, Robert; Wassertheil-Smoller, Sylvia; Zeng, Donglin; Applebaum-Bowden, Deborah; Feolo, Michael; Gan, Weiniu; Paltoo, Dina N.; Sholinsky, Phyliss; Sturcke, Anne

2014-01-01

Elevated low-density lipoprotein cholesterol (LDL-C) is a treatable, heritable risk factor for cardiovascular disease. Genome-wide association studies (GWASs) have identified 157 variants associated with lipid levels but are not well suited to assess the impact of rare and low-frequency variants. To determine whether rare or low-frequency coding variants are associated with LDL-C, we exome sequenced 2,005 individuals, including 554 individuals selected for extreme LDL-C (>98th or <2nd percentile). Follow-up analyses included sequencing of 1,302 additional individuals and genotype-based analysis of 52,221 individuals. We observed significant evidence of association between LDL-C and the burden of rare or low-frequency variants in PNPLA5, encoding a phospholipase-domain-containing protein, and both known and previously unidentified variants in PCSK9, LDLR and APOB, three known lipid-related genes. The effect sizes for the burden of rare variants for each associated gene were substantially higher than those observed for individual SNPs identified from GWASs. We replicated the PNPLA5 signal in an independent large-scale sequencing study of 2,084 individuals. In conclusion, this large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL-C and provides unique insight into the design and analysis of similar experiments. PMID:24507775

Suspect filler similarity in eyewitness lineups: a literature review and a novel methodology.

Science.gov (United States)

Fitzgerald, Ryan J; Oriet, Chris; Price, Heather L

2015-02-01

Eyewitness lineups typically contain a suspect (guilty or innocent) and fillers (known innocents). The degree to which fillers should resemble the suspect is a complex issue that has yet to be resolved. Previously, researchers have voiced concern that eyewitnesses would be unable to identify their target from a lineup containing highly similar fillers; however, our literature review suggests highly similar fillers have only rarely been shown to have this effect. To further examine the effect of highly similar fillers on lineup responses, we used morphing software to create fillers of moderately high and very high similarity to the suspect. When the culprit was in the lineup, a higher correct identification rate was observed in moderately high similarity lineups than in very high similarity lineups. When the culprit was absent, similarity did not yield a significant effect on innocent suspect misidentification rates. However, the correct rejection rate in the moderately high similarity lineup was 20% higher than in the very high similarity lineup. When choosing rates were controlled by calculating identification probabilities for only those who made a selection from the lineup, culprit identification rates as well as innocent suspect misidentification rates were significantly higher in the moderately high similarity lineup than in the very high similarity lineup. Thus, very high similarity fillers yielded costs and benefits. Although our research suggests that selecting the most similar fillers available may adversely affect correct identification rates, we recommend additional research using fillers obtained from police databases to corroborate our findings.

Single-nucleotide polymorphism discovery by high-throughput sequencing in sorghum

Directory of Open Access Journals (Sweden)

White Frank F

2011-07-01

Full Text Available Abstract Background Eight diverse sorghum (Sorghum bicolor L. Moench accessions were subjected to short-read genome sequencing to characterize the distribution of single-nucleotide polymorphisms (SNPs. Two strategies were used for DNA library preparation. Missing SNP genotype data were imputed by local haplotype comparison. The effect of library type and genomic diversity on SNP discovery and imputation are evaluated. Results Alignment of eight genome equivalents (6 Gb to the public reference genome revealed 283,000 SNPs at ≥82% confirmation probability. Sequencing from libraries constructed to limit sequencing to start at defined restriction sites led to genotyping 10-fold more SNPs in all 8 accessions, and correctly imputing 11% more missing data, than from semirandom libraries. The SNP yield advantage of the reduced-representation method was less than expected, since up to one fifth of reads started at noncanonical restriction sites and up to one third of restriction sites predicted in silico to yield unique alignments were not sampled at near-saturation. For imputation accuracy, the availability of a genomically similar accession in the germplasm panel was more important than panel size or sequencing coverage. Conclusions A sequence quantity of 3 million 50-base reads per accession using a BsrFI library would conservatively provide satisfactory genotyping of 96,000 sorghum SNPs. For most reliable SNP-genotype imputation in shallowly sequenced genomes, germplasm panels should consist of pairs or groups of genomically similar entries. These results may help in designing strategies for economical genotyping-by-sequencing of large numbers of plant accessions.

Winnowing sequences from a database search.

Science.gov (United States)

Berman, P; Zhang, Z; Wolf, Y I; Koonin, E V; Miller, W

2000-01-01

In database searches for sequence similarity, matches to a distinct sequence region (e.g., protein domain) are frequently obscured by numerous matches to another region of the same sequence. In order to cope with this problem, algorithms are developed to discard redundant matches. One model for this problem begins with a list of intervals, each with an associated score; each interval gives the range of positions in the query sequence that align to a database sequence, and the score is that of the alignment. If interval I is contained in interval J, and I's score is less than J's, then I is said to be dominated by J. The problem is then to identify each interval that is dominated by at least K other intervals, where K is a given level of "tolerable redundancy." An algorithm is developed to solve the problem in O(N log N) time and O(N*) space, where N is the number of intervals and N* is a precisely defined value that never exceeds N and is frequently much smaller. This criterion for discarding database hits has been implemented in the Blast program, as illustrated herein with examples. Several variations and extensions of this approach are also described.

Lower- Versus Higher-Income Populations In The Alternative Quality Contract: Improved Quality And Similar Spending.

Science.gov (United States)

Song, Zirui; Rose, Sherri; Chernew, Michael E; Safran, Dana Gelb

2017-01-01

As population-based payment models become increasingly common, it is crucial to understand how such payment models affect health disparities. We evaluated health care quality and spending among enrollees in areas with lower versus higher socioeconomic status in Massachusetts before and after providers entered into the Alternative Quality Contract, a two-sided population-based payment model with substantial incentives tied to quality. We compared changes in process measures, outcome measures, and spending between enrollees in areas with lower and higher socioeconomic status from 2006 to 2012 (outcome measures were measured after the intervention only). Quality improved for all enrollees in the Alternative Quality Contract after their provider organizations entered the contract. Process measures improved 1.2 percentage points per year more among enrollees in areas with lower socioeconomic status than among those in areas with higher socioeconomic status. Outcome measure improvement was no different between the subgroups; neither were changes in spending. Larger or comparable improvements in quality among enrollees in areas with lower socioeconomic status suggest a potential narrowing of disparities. Strong pay-for-performance incentives within a population-based payment model could encourage providers to focus on improving quality for more disadvantaged populations. Project HOPE—The People-to-People Health Foundation, Inc.

Characterization of 47 MHC class I sequences in Filipino cynomolgus macaques

Science.gov (United States)

Campbell, Kevin J.; Detmer, Ann M.; Karl, Julie A.; Wiseman, Roger W.; Blasky, Alex J.; Hughes, Austin L.; Bimber, Benjamin N.; O’Connor, Shelby L.; O’Connor, David H.

2009-01-01

Cynomolgus macaques (Macaca fascicularis) provide increasingly common models for infectious disease research. Several geographically distinct populations of these macaques from Southeast Asia and the Indian Ocean island of Mauritius are available for pathogenesis studies. Though host genetics may profoundly impact results of such studies, similarities and differences between populations are often overlooked. In this study we identified 47 full-length MHC class I nucleotide sequences in 16 cynomolgus macaques of Filipino origin. The majority of MHC class I sequences characterized (39 of 47) were unique to this regional population. However, we discovered eight sequences with perfect identity and six sequences with close similarity to previously defined MHC class I sequences from other macaque populations. We identified two ancestral MHC haplotypes that appear to be shared between Filipino and Mauritian cynomolgus macaques, notably a Mafa-B haplotype that has previously been shown to protect Mauritian cynomolgus macaques against challenge with a simian/human immunodeficiency virus, SHIV89.6P. We also identified a Filipino cynomolgus macaque MHC class I sequence for which the predicted protein sequence differs from Mamu-B*17 by a single amino acid. This is important because Mamu-B*17 is strongly associated with protection against simian immunodeficiency virus (SIV) challenge in Indian rhesus macaques. These findings have implications for the evolutionary history of Filipino cynomolgus macaques as well as for the use of this model in SIV/SHIV research protocols. PMID:19107381

Metazoan Remaining Genes for Essential Amino Acid Biosynthesis: Sequence Conservation and Evolutionary Analyses

Directory of Open Access Journals (Sweden)

Igor R. Costa

2014-12-01

Full Text Available Essential amino acids (EAA consist of a group of nine amino acids that animals are unable to synthesize via de novo pathways. Recently, it has been found that most metazoans lack the same set of enzymes responsible for the de novo EAA biosynthesis. Here we investigate the sequence conservation and evolution of all the metazoan remaining genes for EAA pathways. Initially, the set of all 49 enzymes responsible for the EAA de novo biosynthesis in yeast was retrieved. These enzymes were used as BLAST queries to search for similar sequences in a database containing 10 complete metazoan genomes. Eight enzymes typically attributed to EAA pathways were found to be ubiquitous in metazoan genomes, suggesting a conserved functional role. In this study, we address the question of how these genes evolved after losing their pathway partners. To do this, we compared metazoan genes with their fungal and plant orthologs. Using phylogenetic analysis with maximum likelihood, we found that acetolactate synthase (ALS and betaine-homocysteine S-methyltransferase (BHMT diverged from the expected Tree of Life (ToL relationships. High sequence conservation in the paraphyletic group Plant-Fungi was identified for these two genes using a newly developed Python algorithm. Selective pressure analysis of ALS and BHMT protein sequences showed higher non-synonymous mutation ratios in comparisons between metazoans/fungi and metazoans/plants, supporting the hypothesis that these two genes have undergone non-ToL evolution in animals.

Properties of Sequence Conservation in Upstream Regulatory and Protein Coding Sequences among Paralogs in Arabidopsis thaliana

Science.gov (United States)

Richardson, Dale N.; Wiehe, Thomas

Whole genome duplication (WGD) has catalyzed the formation of new species, genes with novel functions, altered expression patterns, complexified signaling pathways and has provided organisms a level of genetic robustness. We studied the long-term evolution and interrelationships of 5’ upstream regulatory sequences (URSs), protein coding sequences (CDSs) and expression correlations (EC) of duplicated gene pairs in Arabidopsis. Three distinct methods revealed significant evolutionary conservation between paralogous URSs and were highly correlated with microarray-based expression correlation of the respective gene pairs. Positional information on exact matches between sequences unveiled the contribution of micro-chromosomal rearrangements on expression divergence. A three-way rank analysis of URS similarity, CDS divergence and EC uncovered specific gene functional biases. Transcription factor activity was associated with gene pairs exhibiting conserved URSs and divergent CDSs, whereas a broad array of metabolic enzymes was found to be associated with gene pairs showing diverged URSs but conserved CDSs.

Sequence Factorization with Multiple References.

Directory of Open Access Journals (Sweden)

Sebastian Wandelt

Full Text Available The success of high-throughput sequencing has lead to an increasing number of projects which sequence large populations of a species. Storage and analysis of sequence data is a key challenge in these projects, because of the sheer size of the datasets. Compression is one simple technology to deal with this challenge. Referential factorization and compression schemes, which store only the differences between input sequence and a reference sequence, gained lots of interest in this field. Highly-similar sequences, e.g., Human genomes, can be compressed with a compression ratio of 1,000:1 and more, up to two orders of magnitude better than with standard compression techniques. Recently, it was shown that the compression against multiple references from the same species can boost the compression ratio up to 4,000:1. However, a detailed analysis of using multiple references is lacking, e.g., for main memory consumption and optimality. In this paper, we describe one key technique for the referential compression against multiple references: The factorization of sequences. Based on the notion of an optimal factorization, we propose optimization heuristics and identify parameter settings which greatly influence 1 the size of the factorization, 2 the time for factorization, and 3 the required amount of main memory. We evaluate a total of 30 setups with a varying number of references on data from three different species. Our results show a wide range of factorization sizes (optimal to an overhead of up to 300%, factorization speed (0.01 MB/s to more than 600 MB/s, and main memory usage (few dozen MB to dozens of GB. Based on our evaluation, we identify the best configurations for common use cases. Our evaluation shows that multi-reference factorization is much better than single-reference factorization.

Sulfamethoxazole and COD increase abundance of sulfonamide resistance genes and change bacterial community structures within sequencing batch reactors.

Science.gov (United States)

Guo, Xueping; Pang, Weihai; Dou, Chunling; Yin, Daqiang

2017-05-01

The abundant microbial community in biological treatment processes in wastewater treatment plants (WWTPs) may potentially enhance the horizontal gene transfer of antibiotic resistance genes with the presence of antibiotics. A lab-scale sequencing batch reactor was designed to investigate response of sulfonamide resistance genes (sulI, sulII) and bacterial communities to various concentrations of sulfamethoxazole (SMX) and chemical oxygen demand (COD) of wastewater. The SMX concentrations (0.001 mg/L, 0.1 mg/L and 10 mg/L) decreased with treatment time and higher SMX level was more difficult to remove. The presence of SMX also significantly reduced the removal efficiency of ammonia nitrogen, affecting the normal function of WWTPs. All three concentrations of SMX raised both sulI and sulII genes with higher concentrations exhibiting greater increases. The abundance of sul genes was positive correlated with treatment time and followed the second-order reaction kinetic model. Interestingly, these two genes have rather similar activity. SulI and sulII gene abundance also performed similar response to COD. Simpson index and Shannon-Weiner index did not show changes in the microbial community diversity. However, the 16S rRNA gene cloning and sequencing results showed the bacterial community structures varied during different stages. The results demonstrated that influent antibiotics into WWTPs may facilitate selection of ARGs and affect the wastewater conventional treatment as well as the bacteria community structures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protecting genomic sequence anonymity with generalization lattices.

Science.gov (United States)

Malin, B A

2005-01-01

Current genomic privacy technologies assume the identity of genomic sequence data is protected if personal information, such as demographics, are obscured, removed, or encrypted. While demographic features can directly compromise an individual's identity, recent research demonstrates such protections are insufficient because sequence data itself is susceptible to re-identification. To counteract this problem, we introduce an algorithm for anonymizing a collection of person-specific DNA sequences. The technique is termed DNA lattice anonymization (DNALA), and is based upon the formal privacy protection schema of k -anonymity. Under this model, it is impossible to observe or learn features that distinguish one genetic sequence from k-1 other entries in a collection. To maximize information retained in protected sequences, we incorporate a concept generalization lattice to learn the distance between two residues in a single nucleotide region. The lattice provides the most similar generalized concept for two residues (e.g. adenine and guanine are both purines). The method is tested and evaluated with several publicly available human population datasets ranging in size from 30 to 400 sequences. Our findings imply the anonymization schema is feasible for the protection of sequences privacy. The DNALA method is the first computational disclosure control technique for general DNA sequences. Given the computational nature of the method, guarantees of anonymity can be formally proven. There is room for improvement and validation, though this research provides the groundwork from which future researchers can construct genomics anonymization schemas tailored to specific datasharing scenarios.

Self-similar transmission properties of aperiodic Cantor potentials in gapped graphene

Science.gov (United States)

Rodríguez-González, Rogelio; Rodríguez-Vargas, Isaac; Díaz-Guerrero, Dan Sidney; Gaggero-Sager, Luis Manuel

2016-01-01

We investigate the transmission properties of quasiperiodic or aperiodic structures based on graphene arranged according to the Cantor sequence. In particular, we have found self-similar behaviour in the transmission spectra, and most importantly, we have calculated the scalability of the spectra. To do this, we implement and propose scaling rules for each one of the fundamental parameters: generation number, height of the barriers and length of the system. With this in mind we have been able to reproduce the reference transmission spectrum, applying the appropriate scaling rule, by means of the scaled transmission spectrum. These scaling rules are valid for both normal and oblique incidence, and as far as we can see the basic ingredients to obtain self-similar characteristics are: relativistic Dirac electrons, a self-similar structure and the non-conservation of the pseudo-spin.

Identification of (R)-selective ω-aminotransferases by exploring evolutionary sequence space.

Science.gov (United States)

Kim, Eun-Mi; Park, Joon Ho; Kim, Byung-Gee; Seo, Joo-Hyun

2018-03-01

Several (R)-selective ω-aminotransferases (R-ωATs) have been reported. The existence of additional R-ωATs having different sequence characteristics from previous ones is highly expected. In addition, it is generally accepted that R-ωATs are variants of aminotransferase group III. Based on these backgrounds, sequences in RefSeq database were scored using family profiles of branched-chain amino acid aminotransferase (BCAT) and d-alanine aminotransferase (DAT) to predict and identify putative R-ωATs. Sequences with two profile analysis scores were plotted on two-dimensional score space. Candidates with relatively similar scores in both BCAT and DAT profiles (i.e., profile analysis score using BCAT profile was similar to profile analysis score using DAT profile) were selected. Experimental results for selected candidates showed that putative R-ωATs from Saccharopolyspora erythraea (R-ωAT_Sery), Bacillus cellulosilyticus (R-ωAT_Bcel), and Bacillus thuringiensis (R-ωAT_Bthu) had R-ωAT activity. Additional experiments revealed that R-ωAT_Sery also possessed DAT activity while R-ωAT_Bcel and R-ωAT_Bthu had BCAT activity. Selecting putative R-ωATs from regions with similar profile analysis scores identified potential R-ωATs. Therefore, R-ωATs could be efficiently identified by using simple family profile analysis and exploring evolutionary sequence space. Copyright © 2017 Elsevier Inc. All rights reserved.

Electromyographic Study of a Sequence of Yau-Man Kung Fu Palm Strikes with and without Impact.

Science.gov (United States)

Neto, Osmar Pinto; Magini, Marcio; Pacheco, Marcos T T

2007-01-01

IN MARTIAL ARTS AND CONTACT SPORTS, STRIKES ARE OFTEN TRAINED IN TWO DIFFERENT WAYS: with and without impacts. This study aims to compare the electromyographical activity (EMG) of the triceps brachii (TB), biceps brachii (BB) and brachioradialis (BR) muscles during strikes with and without impacts. Eight Yau-Man Kung Fu practitioners participated in the experiment. Each participant performed 5 sequences of 5 consecutive KF Yau-Man palm strikes with no impact intercalated with 5 sequences of 5 repetitions targeting a KF training shield. Surface EMG signals were obtained from the TB, BB, and RB for 3.0 seconds using an eight-channel module with a total amplifier gain of 2000 and sampled at 3500 Hz. The EMG analyses were done in the time (rms) and frequency (wavelet) domains. For the frequency domain, Morlet wavelet power spectra were obtained and an original method was used to quantify statistically significant regions on the power spectra. The results both in the time and frequency domains indicate a higher TB and BR muscle activity for the strikes with impacts. No significant difference was found for the BB in the two different scenarios. In addition, the results show that the wavelet power spectra pattern for the three analysed muscles obtained from the strikes with and without impacts were similar. Key pointsEMG analysis of a sequence of Kung Fu strikes demonstrates higher Triceps Brachii and Brachioradialis muscle activity for strikes with impact than strikes without impact.An original reliable method for quantifying EMG wavelet transform results is presented.EMG wavelet power spectra describe muscle roles during a Kung Fu sequence of strikes.

Authentication of ruta graveolens and its adulterant using internal transcribed spacer (its) sequences of nuclear ribosomal DNA

International Nuclear Information System (INIS)

Qurainy, F.A.; Khan, S.; Ali, M.A.; Hemaid, M.A.; Ashraf, M.

2011-01-01

Ruta graveolens L. (Rutaceae) is commonly known as 'Sudab' which is well known for hippocratic medicine and is commonly used in indigenous health-care system in India. Euphorbia dracunculoides Lam. (Euphorbiaceae) in raw drug trading has almost similar morphology to R. graveolens in dried state, is being sold locally or used clinically as an adulterant of R. graveolens (genuine) at a relatively low price under the same name 'Sudab' which has ultimately reduced the efficacy and quality of this herb. The internal transcribed spacer (ITS) sequence of nuclear ribosomal DNA gene of genuine and adulterant were sequenced and analyzed to assess species admixture in raw drug trading of genuine herbal drug. The BLAST search results of ITS sequence of genuine sample of 'Sudab' i.e., R. graveolens showed 99% similarity to the sequence of R. graveolens, however, E. dracunculoides showed 100% similarity to the species of Euphorbia and did not show any similarity with R. graveolens. The sequence alignment of both species was entirely different to each other. Phylogenetic analysis based on ITS sequence of adulterant sample i.e., E. dracunculoides together with sequences of Euphorbia species available in the GenBank has also clearly showed its nesting within the Euphorbia tree. The generated ITS sequences of both samples in the present study may be referred hereafter as species-specific DNA barcode signature, which can be used in authenticating and validating the exact species identities to discriminate the genuine sample of 'Sudab' from its adulterants if any available to guarantee the quality and purity of this drug in the herbal drug market. (author)

Rapid Diagnostics of Onboard Sequences

Science.gov (United States)

Starbird, Thomas W.; Morris, John R.; Shams, Khawaja S.; Maimone, Mark W.

2012-01-01

Keeping track of sequences onboard a spacecraft is challenging. When reviewing Event Verification Records (EVRs) of sequence executions on the Mars Exploration Rover (MER), operators often found themselves wondering which version of a named sequence the EVR corresponded to. The lack of this information drastically impacts the operators diagnostic capabilities as well as their situational awareness with respect to the commands the spacecraft has executed, since the EVRs do not provide argument values or explanatory comments. Having this information immediately available can be instrumental in diagnosing critical events and can significantly enhance the overall safety of the spacecraft. This software provides auditing capability that can eliminate that uncertainty while diagnosing critical conditions. Furthermore, the Restful interface provides a simple way for sequencing tools to automatically retrieve binary compiled sequence SCMFs (Space Command Message Files) on demand. It also enables developers to change the underlying database, while maintaining the same interface to the existing applications. The logging capabilities are also beneficial to operators when they are trying to recall how they solved a similar problem many days ago: this software enables automatic recovery of SCMF and RML (Robot Markup Language) sequence files directly from the command EVRs, eliminating the need for people to find and validate the corresponding sequences. To address the lack of auditing capability for sequences onboard a spacecraft during earlier missions, extensive logging support was added on the Mars Science Laboratory (MSL) sequencing server. This server is responsible for generating all MSL binary SCMFs from RML input sequences. The sequencing server logs every SCMF it generates into a MySQL database, as well as the high-level RML file and dictionary name inputs used to create the SCMF. The SCMF is then indexed by a hash value that is automatically included in all command

Genome Sequences of Oryza Species

KAUST Repository

Kumagai, Masahiko

2018-02-14

This chapter summarizes recent data obtained from genome sequencing, annotation projects, and studies on the genome diversity of Oryza sativa and related Oryza species. O. sativa, commonly known as Asian rice, is the first monocot species whose complete genome sequence was deciphered based on physical mapping by an international collaborative effort. This genome, along with its accurate and comprehensive annotation, has become an indispensable foundation for crop genomics and breeding. With the development of innovative sequencing technologies, genomic studies of O. sativa have dramatically increased; in particular, a large number of cultivars and wild accessions have been sequenced and compared with the reference rice genome. Since de novo genome sequencing has become cost-effective, the genome of African cultivated rice, O. glaberrima, has also been determined. Comparative genomic studies have highlighted the independent domestication processes of different rice species, but it also turned out that Asian and African rice share a common gene set that has experienced similar artificial selection. An international project aimed at constructing reference genomes and examining the genome diversity of wild Oryza species is currently underway, and the genomes of some species are publicly available. This project provides a platform for investigations such as the evolution, development, polyploidization, and improvement of crops. Studies on the genomic diversity of Oryza species, including wild species, should provide new insights to solve the problem of growing food demands in the face of rapid climatic changes.

Genome Sequences of Oryza Species

KAUST Repository

Kumagai, Masahiko; Tanaka, Tsuyoshi; Ohyanagi, Hajime; Hsing, Yue-Ie C.; Itoh, Takeshi

2018-01-01

This chapter summarizes recent data obtained from genome sequencing, annotation projects, and studies on the genome diversity of Oryza sativa and related Oryza species. O. sativa, commonly known as Asian rice, is the first monocot species whose complete genome sequence was deciphered based on physical mapping by an international collaborative effort. This genome, along with its accurate and comprehensive annotation, has become an indispensable foundation for crop genomics and breeding. With the development of innovative sequencing technologies, genomic studies of O. sativa have dramatically increased; in particular, a large number of cultivars and wild accessions have been sequenced and compared with the reference rice genome. Since de novo genome sequencing has become cost-effective, the genome of African cultivated rice, O. glaberrima, has also been determined. Comparative genomic studies have highlighted the independent domestication processes of different rice species, but it also turned out that Asian and African rice share a common gene set that has experienced similar artificial selection. An international project aimed at constructing reference genomes and examining the genome diversity of wild Oryza species is currently underway, and the genomes of some species are publicly available. This project provides a platform for investigations such as the evolution, development, polyploidization, and improvement of crops. Studies on the genomic diversity of Oryza species, including wild species, should provide new insights to solve the problem of growing food demands in the face of rapid climatic changes.

Monomorphism in humans and sequence differences among higher primates for a sequence tagged site (STS) in homeo box cluster 2 as assayed by denaturing gradient electrophoresis

Energy Technology Data Exchange (ETDEWEB)

Ruano, G.; Ruddle, F.H.; Kidd, K.K. (Yale Univ., New Haven, CT (United States)); Gray, M.R. (Tufts Univ., Boston, MA (United States)); Miki, Tetsuro (Osaka Univ. (Japan)); Ferguson-Smith, A.C. (Inst. of Animal Physiology and Genetics Research, Cambridge (United Kingdom))

1990-03-11

The human homeo box cluster 2 (HOX2) contains genes coding for DNA binding proteins involved in developmental control and is highly conserved between mouse and man. The authors have applied in concert the Polymerase Chain Reaction (PCR) and Denaturing Gradient Electrophoresis (DGE) to amplify defined primate HOX2 segments and to detect sequence differences among them. They have sequenced a PstI fragment 4 kb upstream from HOX 2.2 and synthesized primers delimiting both halves of 630 bp segment within it PCR on various unrelated humans and SC-PCR on chimpanzee, gorilla, orangutan and gibbon yielded products of the same length for each primer pair.

Optimizing and benchmarking de novo transcriptome sequencing: from library preparation to assembly evaluation.

Science.gov (United States)

Hara, Yuichiro; Tatsumi, Kaori; Yoshida, Michio; Kajikawa, Eriko; Kiyonari, Hiroshi; Kuraku, Shigehiro

2015-11-18

RNA-seq enables gene expression profiling in selected spatiotemporal windows and yields massive sequence information with relatively low cost and time investment, even for non-model species. However, there remains a large room for optimizing its workflow, in order to take full advantage of continuously developing sequencing capacity. Transcriptome sequencing for three embryonic stages of Madagascar ground gecko (Paroedura picta) was performed with the Illumina platform. The output reads were assembled de novo for reconstructing transcript sequences. In order to evaluate the completeness of transcriptome assemblies, we prepared a reference gene set consisting of vertebrate one-to-one orthologs. To take advantage of increased read length of >150 nt, we demonstrated shortened RNA fragmentation time, which resulted in a dramatic shift of insert size distribution. To evaluate products of multiple de novo assembly runs incorporating reads with different RNA sources, read lengths, and insert sizes, we introduce a new reference gene set, core vertebrate genes (CVG), consisting of 233 genes that are shared as one-to-one orthologs by all vertebrate genomes examined (29 species)., The completeness assessment performed by the computational pipelines CEGMA and BUSCO referring to CVG, demonstrated higher accuracy and resolution than with the gene set previously established for this purpose. As a result of the assessment with CVG, we have derived the most comprehensive transcript sequence set of the Madagascar ground gecko by means of assembling individual libraries followed by clustering the assembled sequences based on their overall similarities. Our results provide several insights into optimizing de novo RNA-seq workflow, including the coordination between library insert size and read length, which manifested in improved connectivity of assemblies. The approach and assembly assessment with CVG demonstrated here would be applicable to transcriptome analysis of other species as

rbcL gene sequences provide evidence for the evolutionary lineages of leptosporangiate ferns.

Science.gov (United States)

Hasebe, M; Omori, T; Nakazawa, M; Sano, T; Kato, M; Iwatsuki, K

1994-06-07

Pteriodophytes have a longer evolutionary history than any other vascular land plant and, therefore, have endured greater loss of phylogenetically informative information. This factor has resulted in substantial disagreements in evaluating characters and, thus, controversy in establishing a stable classification. To compare competing classifications, we obtained DNA sequences of a chloroplast gene. The sequence of 1206 nt of the large subunit of the ribulose-bisphosphate carboxylase gene (rbcL) was determined from 58 species, representing almost all families of leptosporangiate ferns. Phlogenetic trees were inferred by the neighbor-joining and the parsimony methods. The two methods produced almost identical phylogenetic trees that provided insights concerning major general evolutionary trends in the leptosporangiate ferns. Interesting findings were as follows: (i) two morphologically distinct heterosporous water ferns, Marsilea and Salvinia, are sister genera; (ii) the tree ferns (Cyatheaceae, Dicksoniaceae, and Metaxyaceae) are monophyletic; and (iii) polypodioids are distantly related to the gleichenioids in spite of the similarity of their exindusiate soral morphology and are close to the higher indusiate ferns. In addition, the affinities of several "problematic genera" were assessed.

Analytical and functional similarity of Amgen biosimilar ABP 215 to bevacizumab.

Science.gov (United States)

Seo, Neungseon; Polozova, Alla; Zhang, Mingxuan; Yates, Zachary; Cao, Shawn; Li, Huimin; Kuhns, Scott; Maher, Gwendolyn; McBride, Helen J; Liu, Jennifer

ABP 215 is a biosimilar product to bevacizumab. Bevacizumab acts by binding to vascular endothelial growth factor A, inhibiting endothelial cell proliferation and new blood vessel formation, thereby leading to tumor vasculature normalization. The ABP 215 analytical similarity assessment was designed to assess the structural and functional similarity of ABP 215 and bevacizumab sourced from both the United States (US) and the European Union (EU). Similarity assessment was also made between the US- and EU-sourced bevacizumab to assess the similarity between the two products. The physicochemical properties and structural similarity of ABP 215 and bevacizumab were characterized using sensitive state-of-the-art analytical techniques capable of detecting small differences in product attributes. ABP 215 has the same amino acid sequence and exhibits similar post-translational modification profiles compared to bevacizumab. The functional similarity assessment employed orthogonal assays designed to interrogate all expected biological activities, including those known to affect the mechanisms of action for ABP 215 and bevacizumab. More than 20 batches of bevacizumab (US) and bevacizumab (EU), and 13 batches of ABP 215 representing unique drug substance lots were assessed for similarity. The large dataset allows meaningful comparisons and garners confidence in the overall conclusion for the analytical similarity assessment of ABP 215 to both US- and EU-sourced bevacizumab. The structural and purity attributes, and biological properties of ABP 215 are demonstrated to be highly similar to those of bevacizumab.

Origin of introns by 'intronization' of exonic sequences

DEFF Research Database (Denmark)

Irimia, Manuel; Rukov, Jakob Lewin; Penny, David

2008-01-01

The mechanisms of spliceosomal intron creation have proved elusive. Here we describe a new mechanism: the recruitment of internal exonic sequences ('intronization') in Caenorhabditis species. The numbers of intronization events and introns gained by other mechanisms are similar, suggesting that i...

Characterizing novel endogenous retroviruses from genetic variation inferred from short sequence reads

DEFF Research Database (Denmark)

Mourier, Tobias; Mollerup, Sarah; Vinner, Lasse

2015-01-01

From Illumina sequencing of DNA from brain and liver tissue from the lion, Panthera leo, and tumor samples from the pike-perch, Sander lucioperca, we obtained two assembled sequence contigs with similarity to known retroviruses. Phylogenetic analyses suggest that the pike-perch retrovirus belongs...... to the epsilonretroviruses, and the lion retrovirus to the gammaretroviruses. To determine if these novel retroviral sequences originate from an endogenous retrovirus or from a recently integrated exogenous retrovirus, we assessed the genetic diversity of the parental sequences from which the short Illumina reads...

Evolutionary analysis of hepatitis C virus gene sequences from 1953

Science.gov (United States)

Gray, Rebecca R.; Tanaka, Yasuhito; Takebe, Yutaka; Magiorkinis, Gkikas; Buskell, Zelma; Seeff, Leonard; Alter, Harvey J.; Pybus, Oliver G.

2013-01-01

Reconstructing the transmission history of infectious diseases in the absence of medical or epidemiological records often relies on the evolutionary analysis of pathogen genetic sequences. The precision of evolutionary estimates of epidemic history can be increased by the inclusion of sequences derived from ‘archived’ samples that are genetically distinct from contemporary strains. Historical sequences are especially valuable for viral pathogens that circulated for many years before being formally identified, including HIV and the hepatitis C virus (HCV). However, surprisingly few HCV isolates sampled before discovery of the virus in 1989 are currently available. Here, we report and analyse two HCV subgenomic sequences obtained from infected individuals in 1953, which represent the oldest genetic evidence of HCV infection. The pairwise genetic diversity between the two sequences indicates a substantial period of HCV transmission prior to the 1950s, and their inclusion in evolutionary analyses provides new estimates of the common ancestor of HCV in the USA. To explore and validate the evolutionary information provided by these sequences, we used a new phylogenetic molecular clock method to estimate the date of sampling of the archived strains, plus the dates of four more contemporary reference genomes. Despite the short fragments available, we conclude that the archived sequences are consistent with a proposed sampling date of 1953, although statistical uncertainty is large. Our cross-validation analyses suggest that the bias and low statistical power observed here likely arise from a combination of high evolutionary rate heterogeneity and an unstructured, star-like phylogeny. We expect that attempts to date other historical viruses under similar circumstances will meet similar problems. PMID:23938759

Protein backbone angle restraints from searching a database for chemical shift and sequence homology

Energy Technology Data Exchange (ETDEWEB)

Cornilescu, Gabriel; Delaglio, Frank; Bax, Ad [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

1999-03-15

Chemical shifts of backbone atoms in proteins are exquisitely sensitive to local conformation, and homologous proteins show quite similar patterns of secondary chemical shifts. The inverse of this relation is used to search a database for triplets of adjacent residues with secondary chemical shifts and sequence similarity which provide the best match to the query triplet of interest. The database contains 13C{alpha}, 13C{beta}, 13C', 1H{alpha} and 15N chemical shifts for 20 proteins for which a high resolution X-ray structure is available. The computer program TALOS was developed to search this database for strings of residues with chemical shift and residue type homology. The relative importance of the weighting factors attached to the secondary chemical shifts of the five types of resonances relative to that of sequence similarity was optimized empirically. TALOS yields the 10 triplets which have the closest similarity in secondary chemical shift and amino acid sequence to those of the query sequence. If the central residues in these 10 triplets exhibit similar {phi} and {psi} backbone angles, their averages can reliably be used as angular restraints for the protein whose structure is being studied. Tests carried out for proteins of known structure indicate that the root-mean-square difference (rmsd) between the output of TALOS and the X-ray derived backbone angles is about 15 deg. Approximately 3% of the predictions made by TALOS are found to be in error.

Accelerated convergence and robust asymptotic regression of the Gumbel scale parameter for gapped sequence alignment

International Nuclear Information System (INIS)

Park, Yonil; Sheetlin, Sergey; Spouge, John L

2005-01-01

Searches through biological databases provide the primary motivation for studying sequence alignment statistics. Other motivations include physical models of annealing processes or mathematical similarities to, e.g., first-passage percolation and interacting particle systems. Here, we investigate sequence alignment statistics, partly to explore two general mathematical methods. First, we model the global alignment of random sequences heuristically with Markov additive processes. In sequence alignment, the heuristic suggests a numerical acceleration scheme for simulating an important asymptotic parameter (the Gumbel scale parameter λ). The heuristic might apply to similar mathematical theories. Second, we extract the asymptotic parameter λ from simulation data with the statistical technique of robust regression. Robust regression is admirably suited to 'asymptotic regression' and deserves to be better known for it

The Development of Automatic Sequences for the RF and Cryogenic Systems at the Spallation Neutron Source

International Nuclear Information System (INIS)

Gurd, Pamela; Casagrande, Fabio; Mccarthy, Michael; Strong, William; Ganni, Venkatarao

2005-01-01

Automatic sequences both ease the task of operating a complex machine and ensure procedural consistency. At the Spallation Neutron Source project (SNS), a set of automatic sequences have been developed to perform the start up and shut down of the high power RF systems. Similarly, sequences have been developed to perform backfill, pump down, automatic valve control and energy management in the cryogenic system. The sequences run on Linux soft input-output controllers (IOCs), which are similar to ordinary EPICS (Experimental Physics and Industrial Control System) IOCs in terms of data sharing with other EPICS processes, but which share a Linux processor with other such processors. Each sequence waits for a command from an operator console and starts the corresponding set of instructions, allowing operators to follow the sequences either from an overview screen or from detail screens. We describe each system and our operational experience with it.

ITS all right mama: investigating the formation of chimeric sequences in the ITS2 region by DNA metabarcoding analyses of fungal mock communities of different complexities.

Science.gov (United States)

Bjørnsgaard Aas, Anders; Davey, Marie Louise; Kauserud, Håvard

2017-07-01

The formation of chimeric sequences can create significant methodological bias in PCR-based DNA metabarcoding analyses. During mixed-template amplification of barcoding regions, chimera formation is frequent and well documented. However, profiling of fungal communities typically uses the more variable rDNA region ITS. Due to a larger research community, tools for chimera detection have been developed mainly for the 16S/18S markers. However, these tools are widely applied to the ITS region without verification of their performance. We examined the rate of chimera formation during amplification and 454 sequencing of the ITS2 region from fungal mock communities of different complexities. We evaluated the chimera detecting ability of two common chimera-checking algorithms: perseus and uchime. Large proportions of the chimeras reported were false positives. No false negatives were found in the data set. Verified chimeras accounted for only 0.2% of the total ITS2 reads, which is considerably less than what is typically reported in 16S and 18S metabarcoding analyses. Verified chimeric 'parent sequences' had significantly higher per cent identity to one another than to random members of the mock communities. Community complexity increased the rate of chimera formation. GC content was higher around the verified chimeric break points, potentially facilitating chimera formation through base pair mismatching in the neighbouring regions of high similarity in the chimeric region. We conclude that the hypervariable nature of the ITS region seems to buffer the rate of chimera formation in comparison with other, less variable barcoding regions, due to shorter regions of high sequence similarity. © 2016 John Wiley & Sons Ltd.

SCALCE: boosting sequence compression algorithms using locally consistent encoding.

Science.gov (United States)

Hach, Faraz; Numanagic, Ibrahim; Alkan, Can; Sahinalp, S Cenk

2012-12-01

The high throughput sequencing (HTS) platforms generate unprecedented amounts of data that introduce challenges for the computational infrastructure. Data management, storage and analysis have become major logistical obstacles for those adopting the new platforms. The requirement for large investment for this purpose almost signalled the end of the Sequence Read Archive hosted at the National Center for Biotechnology Information (NCBI), which holds most of the sequence data generated world wide. Currently, most HTS data are compressed through general purpose algorithms such as gzip. These algorithms are not designed for compressing data generated by the HTS platforms; for example, they do not take advantage of the specific nature of genomic sequence data, that is, limited alphabet size and high similarity among reads. Fast and efficient compression algorithms designed specifically for HTS data should be able to address some of the issues in data management, storage and communication. Such algorithms would also help with analysis provided they offer additional capabilities such as random access to any read and indexing for efficient sequence similarity search. Here we present SCALCE, a 'boosting' scheme based on Locally Consistent Parsing technique, which reorganizes the reads in a way that results in a higher compression speed and compression rate, independent of the compression algorithm in use and without using a reference genome. Our tests indicate that SCALCE can improve the compression rate achieved through gzip by a factor of 4.19-when the goal is to compress the reads alone. In fact, on SCALCE reordered reads, gzip running time can improve by a factor of 15.06 on a standard PC with a single core and 6 GB memory. Interestingly even the running time of SCALCE + gzip improves that of gzip alone by a factor of 2.09. When compared with the recently published BEETL, which aims to sort the (inverted) reads in lexicographic order for improving bzip2, SCALCE + gzip

Genome sequence analysis of predicted polyprenol reductase gene from mangrove plant kandelia obovata

Science.gov (United States)

Basyuni, M.; Sagami, H.; Baba, S.; Oku, H.

2018-03-01

It has been previously reported that dolichols but not polyprenols were predominated in mangrove leaves and roots. Therefore, the occurrence of larger amounts of dolichol in leaves of mangrove plants implies that polyprenol reductase is responsible for the conversion of polyprenol to dolichol may be active in mangrove leaves. Here we report the early assessment of probably polyprenol reductase gene from genome sequence of mangrove plant Kandelia obovata. The functional assignment of the gene was based on a homology search of the sequences against the non-redundant (nr) peptide database of NCBI using Blastx. The degree of sequence identity between DNA sequence and known polyprenol reductase was confirmed using the Blastx probability E-value, total score, and identity. The genome sequence data resulted in three partial sequences, termed c23157 (700 bp), c23901 (960 bp), and c24171 (531 bp). The c23157 gene showed the highest similarity (61%) to predicted polyprenol reductase 2- like from Gossypium raimondii with E-value 2e-100. The second gene was c23901 to exhibit high similarity (78%) to the steroid 5-alpha-reductase Det2 from J. curcas with E-value 2e-140. Furthermore, the c24171 gene depicted highest similarity (79%) to the polyprenol reductase 2 isoform X1 from Jatropha curcas with E- value 7e-21.The present study suggested that the c23157, c23901, and c24171, genes may encode predicted polyprenol reductase. The c23157, c23901, c24171 are therefore the new type of predicted polyprenol reductase from K. obovata.

Third-Generation Sequencing and Analysis of Four Complete Pig Liver Esterase Gene Sequences in Clones Identified by Screening BAC Library.

Science.gov (United States)

Zhou, Qiongqiong; Sun, Wenjuan; Liu, Xiyan; Wang, Xiliang; Xiao, Yuncai; Bi, Dingren; Yin, Jingdong; Shi, Deshi

2016-01-01

Pig liver carboxylesterase (PLE) gene sequences in GenBank are incomplete, which has led to difficulties in studying the genetic structure and regulation mechanisms of gene expression of PLE family genes. The aim of this study was to obtain and analysis of complete gene sequences of PLE family by screening from a Rongchang pig BAC library and third-generation PacBio gene sequencing. After a number of existing incomplete PLE isoform gene sequences were analysed, primers were designed based on conserved regions in PLE exons, and the whole pig genome used as a template for Polymerase chain reaction (PCR) amplification. Specific primers were then selected based on the PCR amplification results. A three-step PCR screening method was used to identify PLE-positive clones by screening a Rongchang pig BAC library and PacBio third-generation sequencing was performed. BLAST comparisons and other bioinformatics methods were applied for sequence analysis. Five PLE-positive BAC clones, designated BAC-10, BAC-70, BAC-75, BAC-119 and BAC-206, were identified. Sequence analysis yielded the complete sequences of four PLE genes, PLE1, PLE-B9, PLE-C4, and PLE-G2. Complete PLE gene sequences were defined as those containing regulatory sequences, exons, and introns. It was found that, not only did the PLE exon sequences of the four genes show a high degree of homology, but also that the intron sequences were highly similar. Additionally, the regulatory region of the genes contained two 720bps reverse complement sequences that may have an important function in the regulation of PLE gene expression. This is the first report to confirm the complete sequences of four PLE genes. In addition, the study demonstrates that each PLE isoform is encoded by a single gene and that the various genes exhibit a high degree of sequence homology, suggesting that the PLE family evolved from a single ancestral gene. Obtaining the complete sequences of these PLE genes provides the necessary foundation for

Highly multiplexed targeted DNA sequencing from single nuclei.

Science.gov (United States)

Leung, Marco L; Wang, Yong; Kim, Charissa; Gao, Ruli; Jiang, Jerry; Sei, Emi; Navin, Nicholas E

2016-02-01

Single-cell DNA sequencing methods are challenged by poor physical coverage, high technical error rates and low throughput. To address these issues, we developed a single-cell DNA sequencing protocol that combines flow-sorting of single nuclei, time-limited multiple-displacement amplification (MDA), low-input library preparation, DNA barcoding, targeted capture and next-generation sequencing (NGS). This approach represents a major improvement over our previous single nucleus sequencing (SNS) Nature Protocols paper in terms of generating higher-coverage data (>90%), thereby enabling the detection of genome-wide variants in single mammalian cells at base-pair resolution. Furthermore, by pooling 48-96 single-cell libraries together for targeted capture, this approach can be used to sequence many single-cell libraries in parallel in a single reaction. This protocol greatly reduces the cost of single-cell DNA sequencing, and it can be completed in 5-6 d by advanced users. This single-cell DNA sequencing protocol has broad applications for studying rare cells and complex populations in diverse fields of biological research and medicine.

Long-term oil contamination causes similar changes in microbial communities of two distinct soils.

Science.gov (United States)

Liao, Jingqiu; Wang, Jie; Jiang, Dalin; Wang, Michael Cai; Huang, Yi

2015-12-01

Since total petroleum hydrocarbons (TPH) are toxic and persistent in environments, studying the impact of oil contamination on microbial communities in different soils is vital to oil production engineering, effective soil management and pollution control. This study analyzed the impact of oil contamination on the structure, activity and function in carbon metabolism of microbial communities of Chernozem soil from Daqing oil field and Cinnamon soil from Huabei oil field through both culture-dependent techniques and a culture-independent technique-pyrosequencing. Results revealed that pristine microbial communities in these two soils presented disparate patterns, where Cinnamon soil showed higher abundance of alkane, (polycyclic aromatic hydrocarbons) PAHs and TPH degraders, number of cultivable microbes, bacterial richness, bacterial biodiversity, and stronger microbial activity and function in carbon metabolism than Chernozem soil. It suggested that complicated properties of microbes and soils resulted in the difference in soil microbial patterns. However, the changes of microbial communities caused by oil contamination were similar in respect of two dominant phenomena. Firstly, the microbial community structures were greatly changed, with higher abundance, higher bacterial biodiversity, occurrence of Candidate_division_BRC1 and TAO6, disappearance of BD1-5 and Candidate_division_OD1, dominance of Streptomyces, higher percentage of hydrocarbon-degrading groups, and lower percentage of nitrogen-transforming groups. Secondly, microbial activity and function in carbon metabolism were significantly enhanced. Based on the characteristics of microbial communities in the two soils, appropriate strategy for in situ bioremediation was provided for each oil field. This research underscored the usefulness of combination of culture-dependent techniques and next-generation sequencing techniques both to unravel the microbial patterns and understand the ecological impact of

Comparing an accelerated 3D fast spin-echo sequence (CS-SPACE) for knee 3-T magnetic resonance imaging with traditional 3D fast spin-echo (SPACE) and routine 2D sequences

Energy Technology Data Exchange (ETDEWEB)

Altahawi, Faysal F.; Blount, Kevin J.; Omar, Imran M. [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Morley, Nicholas P. [Marshfield Clinic, Department of Radiology, Marshfield, WI (United States); Raithel, Esther [Siemens Healthcare GmbH, Erlangen (Germany)

2017-01-15

To compare a faster, new, high-resolution accelerated 3D-fast-spin-echo (3D-FSE) acquisition sequence (CS-SPACE) to traditional 2D and high-resolution 3D sequences for knee 3-T magnetic resonance imaging (MRI). Twenty patients received knee MRIs that included routine 2D (T1, PD ± FS, T2-FS; 0.5 x 0.5 x 3 mm{sup 3}; ∝10 min), traditional 3D FSE (SPACE-PD-FS; 0.5 x 0.5 x 0.5 mm{sup 3}; ∝7.5 min), and accelerated 3D-FSE prototype (CS-SPACE-PD-FS; 0.5 x 0.5 x 0.5 mm{sup 3}; ∝5 min) acquisitions on a 3-T MRI system (Siemens MAGNETOM Skyra). Three musculoskeletal radiologists (MSKRs) prospectively and independently reviewed the studies with graded surveys comparing image and diagnostic quality. Tissue-specific signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were also compared. MSKR-perceived diagnostic quality of cartilage was significantly higher for CS-SPACE than for SPACE and 2D sequences (p < 0.001). Assessment of diagnostic quality of menisci and synovial fluid was higher for CS-SPACE than for SPACE (p < 0.001). CS-SPACE was not significantly different from SPACE but had lower assessments than 2D sequences for evaluation of bones, ligaments, muscles, and fat (p ≤ 0.004). 3D sequences had higher spatial resolution, but lower overall assessed contrast (p < 0.001). Overall image quality from CS-SPACE was assessed as higher than SPACE (p = 0.007), but lower than 2D sequences (p < 0.001). Compared to SPACE, CS-SPACE had higher fluid SNR and CNR against all other tissues (all p < 0.001). The CS-SPACE prototype allows for faster isotropic acquisitions of knee MRIs over currently used protocols. High fluid-to-cartilage CNR and higher spatial resolution over routine 2D sequences may present a valuable role for CS-SPACE in the evaluation of cartilage and menisci. (orig.)

Identification of Y-Chromosome Sequences in Turner Syndrome.

Science.gov (United States)

Silva-Grecco, Roseane Lopes da; Trovó-Marqui, Alessandra Bernadete; Sousa, Tiago Alves de; Croce, Lilian Da; Balarin, Marly Aparecida Spadotto

2016-05-01

To investigate the presence of Y-chromosome sequences and determine their frequency in patients with Turner syndrome. The study included 23 patients with Turner syndrome from Brazil, who gave written informed consent for participating in the study. Cytogenetic analyses were performed in peripheral blood lymphocytes, with 100 metaphases per patient. Genomic DNA was also extracted from peripheral blood lymphocytes, and gene sequences DYZ1, DYZ3, ZFY and SRY were amplified by Polymerase Chain Reaction. The cytogenetic analysis showed a 45,X karyotype in 9 patients (39.2 %) and a mosaic pattern in 14 (60.8 %). In 8.7 % (2 out of 23) of the patients, Y-chromosome sequences were found. This prevalence is very similar to those reported previously. The initial karyotype analysis of these patients did not reveal Y-chromosome material, but they were found positive for Y-specific sequences in the lymphocyte DNA analysis. The PCR technique showed that 2 (8.7 %) of the patients with Turner syndrome had Y-chromosome sequences, both presenting marker chromosomes on cytogenetic analysis.

Very high resolution single pass HLA genotyping using amplicon sequencing on the 454 next generation DNA sequencers: Comparison with Sanger sequencing.

Science.gov (United States)

Yamamoto, F; Höglund, B; Fernandez-Vina, M; Tyan, D; Rastrou, M; Williams, T; Moonsamy, P; Goodridge, D; Anderson, M; Erlich, H A; Holcomb, C L

2015-12-01

Compared to Sanger sequencing, next-generation sequencing offers advantages for high resolution HLA genotyping including increased throughput, lower cost, and reduced genotype ambiguity. Here we describe an enhancement of the Roche 454 GS GType HLA genotyping assay to provide very high resolution (VHR) typing, by the addition of 8 primer pairs to the original 14, to genotype 11 HLA loci. These additional amplicons help resolve common and well-documented alleles and exclude commonly found null alleles in genotype ambiguity strings. Simplification of workflow to reduce the initial preparation effort using early pooling of amplicons or the Fluidigm Access Array™ is also described. Performance of the VHR assay was evaluated on 28 well characterized cell lines using Conexio Assign MPS software which uses genomic, rather than cDNA, reference sequence. Concordance was 98.4%; 1.6% had no genotype assignment. Of concordant calls, 53% were unambiguous. To further assess the assay, 59 clinical samples were genotyped and results compared to unambiguous allele assignments obtained by prior sequence-based typing supplemented with SSO and/or SSP. Concordance was 98.7% with 58.2% as unambiguous calls; 1.3% could not be assigned. Our results show that the amplicon-based VHR assay is robust and can replace current Sanger methodology. Together with software enhancements, it has the potential to provide even higher resolution HLA typing. Copyright © 2015. Published by Elsevier Inc.

Automated degenerate PCR primer design for high-throughput sequencing improves efficiency of viral sequencing

Directory of Open Access Journals (Sweden)

Li Kelvin

2012-11-01

Full Text Available Abstract Background In a high-throughput environment, to PCR amplify and sequence a large set of viral isolates from populations that are potentially heterogeneous and continuously evolving, the use of degenerate PCR primers is an important strategy. Degenerate primers allow for the PCR amplification of a wider range of viral isolates with only one set of pre-mixed primers, thus increasing amplification success rates and minimizing the necessity for genome finishing activities. To successfully select a large set of degenerate PCR primers necessary to tile across an entire viral genome and maximize their success, this process is best performed computationally. Results We have developed a fully automated degenerate PCR primer design system that plays a key role in the J. Craig Venter Institute’s (JCVI high-throughput viral sequencing pipeline. A consensus viral genome, or a set of consensus segment sequences in the case of a segmented virus, is specified using IUPAC ambiguity codes in the consensus template sequence to represent the allelic diversity of the target population. PCR primer pairs are then selected computationally to produce a minimal amplicon set capable of tiling across the full length of the specified target region. As part of the tiling process, primer pairs are computationally screened to meet the criteria for successful PCR with one of two described amplification protocols. The actual sequencing success rates for designed primers for measles virus, mumps virus, human parainfluenza virus 1 and 3, human respiratory syncytial virus A and B and human metapneumovirus are described, where >90% of designed primer pairs were able to consistently successfully amplify >75% of the isolates. Conclusions Augmenting our previously developed and published JCVI Primer Design Pipeline, we achieved similarly high sequencing success rates with only minor software modifications. The recommended methodology for the construction of the consensus

On the Use of Normalized Compression Distances for Image Similarity Detection

Directory of Open Access Journals (Sweden)

Dinu Coltuc

2018-01-01

Full Text Available This paper investigates the usefulness of the normalized compression distance (NCD for image similarity detection. Instead of the direct NCD between images, the paper considers the correlation between NCD based feature vectors extracted for each image. The vectors are derived by computing the NCD between the original image and sequences of translated (rotated versions. Feature vectors for simple transforms (circular translations on horizontal, vertical, diagonal directions and rotations around image center and several standard compressors are generated and tested in a very simple experiment of similarity detection between the original image and two filtered versions (median and moving average. The promising vector configurations (geometric transform, lossless compressor are further tested for similarity detection on the 24 images of the Kodak set subject to some common image processing. While the direct computation of NCD fails to detect image similarity even in the case of simple median and moving average filtering in 3 × 3 windows, for certain transforms and compressors, the proposed approach appears to provide robustness at similarity detection against smoothing, lossy compression, contrast enhancement, noise addition and some robustness against geometrical transforms (scaling, cropping and rotation.

Mouse tetranectin: cDNA sequence, tissue-specific expression, and chromosomal mapping

DEFF Research Database (Denmark)

Ibaraki, K; Kozak, C A; Wewer, U M

1995-01-01

regulation, mouse tetranectin cDNA was cloned from a 16-day-old mouse embryo library. Sequence analysis revealed a 992-bp cDNA with an open reading frame of 606 bp, which is identical in length to the human tetranectin cDNA. The deduced amino acid sequence showed high homology to the human cDNA with 76......(s) of tetranectin. The sequence analysis revealed a difference in both sequence and size of the noncoding regions between mouse and human cDNAs. Northern analysis of the various tissues from mouse, rat, and cow showed the major transcript(s) to be approximately 1 kb, which is similar in size to that observed...

True single-molecule DNA sequencing of a pleistocene horse bone

DEFF Research Database (Denmark)

Orlando, Ludovic Antoine Alexandre; Ginolhac, Aurélien; Raghavan, Maanasa

2011-01-01

-preserved Pleistocene horse bone using the Helicos HeliScope and Illumina GAIIx platforms, respectively. We find that the percentage of endogenous DNA sequences derived from the horse is higher among the Helicos data than Illumina data. This result indicates that the molecular biology tools used to generate sequencing...

Curriculum Mapping in Higher Education: A Case Study and Proposed Content Scope and Sequence Mapping Tool

Science.gov (United States)

Arafeh, Sousan

2016-01-01

Best practice in curriculum development and implementation requires that discipline-based standards or requirements embody both curricular and programme scopes and sequences. Ensuring these are present and aligned in course/programme content, activities and assessments to support student success requires formalised and systematised review and…

Comparative analyses of six solanaceous transcriptomes reveal a high degree of sequence conservation and species-specific transcripts

Directory of Open Access Journals (Sweden)

Ouyang Shu

2005-09-01

Full Text Available Abstract Background The Solanaceae is a family of closely related species with diverse phenotypes that have been exploited for agronomic purposes. Previous studies involving a small number of genes suggested sequence conservation across the Solanaceae. The availability of large collections of Expressed Sequence Tags (ESTs for the Solanaceae now provides the opportunity to assess sequence conservation and divergence on a genomic scale. Results All available ESTs and Expressed Transcripts (ETs, 449,224 sequences for six Solanaceae species (potato, tomato, pepper, petunia, tobacco and Nicotiana benthamiana, were clustered and assembled into gene indices. Examination of gene ontologies revealed that the transcripts within the gene indices encode a similar suite of biological processes. Although the ESTs and ETs were derived from a variety of tissues, 55–81% of the sequences had significant similarity at the nucleotide level with sequences among the six species. Putative orthologs could be identified for 28–58% of the sequences. This high degree of sequence conservation was supported by expression profiling using heterologous hybridizations to potato cDNA arrays that showed similar expression patterns in mature leaves for all six solanaceous species. 16–19% of the transcripts within the six Solanaceae gene indices did not have matches among Solanaceae, Arabidopsis, rice or 21 other plant gene indices. Conclusion Results from this genome scale analysis confirmed a high level of sequence conservation at the nucleotide level of the coding sequence among Solanaceae. Additionally, the results indicated that part of the Solanaceae transcriptome is likely to be unique for each species.

eShadow: A tool for comparing closely related sequences

Energy Technology Data Exchange (ETDEWEB)

Ovcharenko, Ivan; Boffelli, Dario; Loots, Gabriela G.

2004-01-15

Primate sequence comparisons are difficult to interpret due to the high degree of sequence similarity shared between such closely related species. Recently, a novel method, phylogenetic shadowing, has been pioneered for predicting functional elements in the human genome through the analysis of multiple primate sequence alignments. We have expanded this theoretical approach to create a computational tool, eShadow, for the identification of elements under selective pressure in multiple sequence alignments of closely related genomes, such as in comparisons of human to primate or mouse to rat DNA. This tool integrates two different statistical methods and allows for the dynamic visualization of the resulting conservation profile. eShadow also includes a versatile optimization module capable of training the underlying Hidden Markov Model to differentially predict functional sequences. This module grants the tool high flexibility in the analysis of multiple sequence alignments and in comparing sequences with different divergence rates. Here, we describe the eShadow comparative tool and its potential uses for analyzing both multiple nucleotide and protein alignments to predict putative functional elements. The eShadow tool is publicly available at http://eshadow.dcode.org/

DNA base sequence changes induced by ultraviolet light mutagenesis of a gene on a chromosome in Chinese hamster ovary cells

Energy Technology Data Exchange (ETDEWEB)

Romac, S; Leong, P; Sockett, H; Hutchinson, F [Yale Univ., New Haven, CT (USA). Dept. of Molecular Biophysics and Biochemistry

1989-09-20

The DNA base sequence changes induced by mutagenesis with ultraviolet light have been determined in a gene on a chromosome of cultured Chinese hamster ovary (CHO) cells. The gene was the Excherichia coli gpt gene, of which a single copy was stably incorporated and expressed in the CHO cell genome. The cells were irradiated with ultraviolet light and gpt{sup -} colonies were selected by resistance to 6-thioguanine. The gpt gene was amplified from chromosomal DNA by use of the polymerase chain reaction (PCR) and the amplified DNA sequenced directly by the dideoxy method. Of the 58 sequenced mutants of independent origin 53 were base change mutations. Forty-one base substitutions were single base changes, ten had two adjacent (or tandem) base changes, and one had two base changes separated by a single base-pair. Only one mutant had a multiple base change mutation with two or more well separated base changes. In contrast much higher levels of such mutations were reported in ultraviolet mutagenesis of genes on a shuttle vector in primate cells. Two deletions of a single base-pair were observed and three deletions ranging from 6 to 37 base-pairs. The mutation spectrum in the gpt gene had similarities to the ultraviolet mutation spectra for several genes in prokaryotes, which suggests similarities in mutational mechanisms in prokaryotes and eukaryotes. (author).

Evolutionary genomics of plant genes encoding N-terminal-TM-C2 domain proteins and the similar FAM62 genes and synaptotagmin genes of metazoans

Directory of Open Access Journals (Sweden)

Craxton Molly

2007-07-01

Full Text Available Abstract Background Synaptotagmin genes are found in animal genomes and are known to function in the nervous system. Genes with a similar domain architecture as well as sequence similarity to synaptotagmin C2 domains have also been found in plant genomes. The plant genes share an additional region of sequence similarity with a group of animal genes named FAM62. FAM62 genes also have a similar domain architecture. Little is known about the functions of the plant genes and animal FAM62 genes. Indeed, many members of the large and diverse Syt gene family await functional characterization. Understanding the evolutionary relationships among these genes will help to realize the full implications of functional studies and lead to improved genome annotation. Results I collected and compared plant Syt-like sequences from the primary nucleotide sequence databases at NCBI. The collection comprises six groups of plant genes conserved in embryophytes: NTMC2Type1 to NTMC2Type6. I collected and compared metazoan FAM62 sequences and identified some similar sequences from other eukaryotic lineages. I found evidence of RNA editing and alternative splicing. I compared the intron patterns of Syt genes. I also compared Rabphilin and Doc2 genes. Conclusion Genes encoding proteins with N-terminal-transmembrane-C2 domain architectures resembling synaptotagmins, are widespread in eukaryotes. A collection of these genes is presented here. The collection provides a resource for studies of intron evolution. I have classified the collection into homologous gene families according to distinctive patterns of sequence conservation and intron position. The evolutionary histories of these gene families are traceable through the appearance of family members in different eukaryotic lineages. Assuming an intron-rich eukaryotic ancestor, the conserved intron patterns distinctive of individual gene families, indicate independent origins of Syt, FAM62 and NTMC2 genes. Resemblances

Zonadhesin D3-polypeptides vary among species but are similar in Equus species capable of interbreeding.

Science.gov (United States)

Tardif, Steve; Brady, Heidi A; Breazeale, Kelly R; Bi, Ming; Thompson, Leslie D; Bruemmer, Jason E; Bailey, Laura B; Hardy, Daniel M

2010-02-01

Zonadhesin is a rapidly evolving protein in the sperm acrosome that confers species specificity to sperm-zona pellucida adhesion. Though structural variation in zonadhesin likely contributes to its species-specific function, the protein has not previously been characterized in organisms capable of interbreeding. Here we compared properties of zonadhesin in several animals, including the horse (Equus caballus), donkey (E. asinus), and Grevy's zebra (E. grevyi) to determine if variation in zonadhesin correlates with ability of gametes to cross-fertilize. Zonadhesin localized to the apical acrosomes of spermatozoa from all three Equus species, similar to its localization in other animals. Likewise, in horse and donkey testis, zonadhesin was detected only in germ cells, first in the acrosomal granule of round spermatids and then in the developing acrosomes of elongating spermatids. Among non-Equus species, D3-domain polypeptides of mature, processed zonadhesin varied markedly in size and detergent solubility. However, zonadhesin D3-domain polypeptides in horse, donkey, and zebra spermatozoa exhibited identical electrophoretic mobility and detergent solubility. Equus zonadhesin D3-polypeptides (p110/p80 doublet) were most similar in size to porcine and bovine zonadhesin D3-polypeptides (p105). Sequence comparisons revealed that the horse zonadhesin precursor's domain content and arrangement are similar to those of zonadhesin from other large animals. Partial sequences of horse and donkey zonadhesin were much more similar to each other (>99% identity) than they were to orthologous sequences of human, pig, rabbit, and mouse zonadhesin (52%-72% identity). We conclude that conservation of zonadhesin D3-polypeptide properties correlates with ability of Equus species to interbreed.

DNA sequence of 15 base pairs is sufficient to mediate both glucocorticoid and progesterone induction of gene expression

International Nuclear Information System (INIS)

Straehle, U.; Klock, G.; Schuetz, G.

1987-01-01

To define the recognition sequence of the glucocorticoid receptor and its relationship with that of the progesterone receptor, oligonucleotides derived from the glucocorticoid response element of the tyrosine aminotransferase gene were tested upstream of a heterologous promoter for their capacity to mediate effects of these two steroids. The authors show that a 15-base-pair sequence with partial symmetry is sufficient to confer glucocorticoid inducibility on the promoter of the herpes simplex virus thymidine kinase gene. The same 15-base-pair sequence mediates induction by progesterone. Point mutations in the recognition sequence affect inducibility by glucocorticoids and progesterone similarly. Together with the strong conservation of the sequence of the DNA-binding domain of the two receptors, these data suggest that both proteins recognize a sequence that is similar, if not the same

Genetic Relationships among Reptilian and Mammalian Campylobacter fetus Strains Determined by Multilocus Sequence Typing

NARCIS (Netherlands)

Dingle, K.E.; Blaser, M.J.; Tu, Z.C.; Pruckler, J.; Fitzgerald, C.; Bergen, van M.A.P.; Lawson, A.J.; Owen, R.J.; Wagenaar, J.A.

2010-01-01

Reptile Campylobacter fetus isolates and closely related strains causing human disease were characterized by multilocus sequence typing. They shared similar to 90% nucleotide sequence identity with classical mammalian C. fetus, and there was evidence of recombination among members of these two

Unraveling systematic inventory of Echinops (Asteraceae) with special reference to nrDNA ITS sequence-based molecular typing of Echinops abuzinadianus.

Science.gov (United States)

Ali, M A; Al-Hemaid, F M; Lee, J; Hatamleh, A A; Gyulai, G; Rahman, M O

2015-10-02

The present study explored the systematic inventory of Echinops L. (Asteraceae) of Saudi Arabia, with special reference to the molecular typing of Echinops abuzinadianus Chaudhary, an endemic species to Saudi Arabia, based on the internal transcribed spacer (ITS) sequences (ITS1-5.8S-ITS2) of nuclear ribosomal DNA. A sequence similarity search using BLAST and a phylogenetic analysis of the ITS sequence of E. abuzinadianus revealed a high level of sequence similarity with E. glaberrimus DC. (section Ritropsis). The novel primary sequence and the secondary structure of ITS2 of E. abuzinadianus could potentially be used for molecular genotyping.

Institutional Variables and Perceived Environmental Concerns in Higher Education.

Science.gov (United States)

Michael, Steve O.

1995-01-01

Discusses the effects of worsening financial constraints evident in all aspects of higher education institutions. Examines differences and similarities in institutional leaders' opinions regarding environmental concerns. All Alberta, Canada, higher education institutions are experiencing similar problems. There is no deliberate shift in government…

On the relationship between perceptual impact of source and channel distortions in video sequences

DEFF Research Database (Denmark)

Korhonen, Jari; Reiter, Ulrich; You, Junyong

2010-01-01

It is known that peak signal-to-noise ratio (PSNR) can be used for assessing the relative qualities of distorted video sequences meaningfully only if the compared sequences contain similar types of distortions. In this paper, we propose a model for rough assessment of the bias in PSNR results, when...... video sequences with both channel and source distortion are compared against video sequences with source distortion only. The proposed method can be used to compare the relative perceptual quality levels of video sequences with different distortion types more reliably than using plain PSNR....

Higher-Order and Symbolic Computation

DEFF Research Database (Denmark)

Danvy, Olivier; Mason, Ian

2008-01-01

a series of implementaions that properly account for multiple invocations of the derivative-taking opeatro. In "Adapting Functional Programs to Higher-Order Logic," Scott Owens and Konrad Slind present a variety of examples of terminiation proofs of functional programs written in HOL proof systems. Since......-calculus programs, historically. The anaylsis determines the possible locations of ambients and mirrors the temporla sequencing of actions in the structure of types....

Compressional Alfven Eigenmode Similarity Study

Science.gov (United States)

Heidbrink, W. W.; Fredrickson, E. D.; Gorelenkov, N. N.; Rhodes, T. L.

2004-11-01

NSTX and DIII-D are nearly ideal for Alfven eigenmode (AE) similarity experiments, having similar neutral beams, fast-ion to Alfven speed v_f/v_A, fast-ion pressure, and shape of the plasma, but with a factor of 2 difference in the major radius. Toroidicity-induced AE with ˜100 kHz frequencies were compared in an earlier study [1]; this paper focuses on higher frequency AE with f ˜ 1 MHz. Compressional AE (CAE) on NSTX have a polarization, dependence on the fast-ion distribution function, frequency scaling, and low-frequency limit that are qualitatively consistent with CAE theory [2]. Global AE (GAE) are also observed. On DIII-D, coherent modes in this frequency range are observed during low-field (0.6 T) similarity experiments. Experiments will compare the CAE stability limits on DIII-D with the NSTX stability limits, with the aim of determining if CAE will be excited by alphas in a reactor. Predicted differences in the frequency splitting Δ f between excited modes will also be used. \\vspace0.25em [1] W.W. Heidbrink, et al., Plasmas Phys. Control. Fusion 45, 983 (2003). [2] E.D. Fredrickson, et al., Princeton Plasma Physics Laboratory Report PPPL-3955 (2004).

Short-read reading-frame predictors are not created equal: sequence error causes loss of signal

Directory of Open Access Journals (Sweden)

Trimble William L

2012-07-01

Full Text Available Abstract Background Gene prediction algorithms (or gene callers are an essential tool for analyzing shotgun nucleic acid sequence data. Gene prediction is a ubiquitous step in sequence analysis pipelines; it reduces the volume of data by identifying the most likely reading frame for a fragment, permitting the out-of-frame translations to be ignored. In this study we evaluate five widely used ab initio gene-calling algorithms—FragGeneScan, MetaGeneAnnotator, MetaGeneMark, Orphelia, and Prodigal—for accuracy on short (75–1000 bp fragments containing sequence error from previously published artificial data and “real” metagenomic datasets. Results While gene prediction tools have similar accuracies predicting genes on error-free fragments, in the presence of sequencing errors considerable differences between tools become evident. For error-containing short reads, FragGeneScan finds more prokaryotic coding regions than does MetaGeneAnnotator, MetaGeneMark, Orphelia, or Prodigal. This improved detection of genes in error-containing fragments, however, comes at the cost of much lower (50% specificity and overprediction of genes in noncoding regions. Conclusions Ab initio gene callers offer a significant reduction in the computational burden of annotating individual nucleic acid reads and are used in many metagenomic annotation systems. For predicting reading frames on raw reads, we find the hidden Markov model approach in FragGeneScan is more sensitive than other gene prediction tools, while Prodigal, MGA, and MGM are better suited for higher-quality sequences such as assembled contigs.

Harnessing Whole Genome Sequencing in Medical Mycology.

Science.gov (United States)

Cuomo, Christina A

2017-01-01

Comparative genome sequencing studies of human fungal pathogens enable identification of genes and variants associated with virulence and drug resistance. This review describes current approaches, resources, and advances in applying whole genome sequencing to study clinically important fungal pathogens. Genomes for some important fungal pathogens were only recently assembled, revealing gene family expansions in many species and extreme gene loss in one obligate species. The scale and scope of species sequenced is rapidly expanding, leveraging technological advances to assemble and annotate genomes with higher precision. By using iteratively improved reference assemblies or those generated de novo for new species, recent studies have compared the sequence of isolates representing populations or clinical cohorts. Whole genome approaches provide the resolution necessary for comparison of closely related isolates, for example, in the analysis of outbreaks or sampled across time within a single host. Genomic analysis of fungal pathogens has enabled both basic research and diagnostic studies. The increased scale of sequencing can be applied across populations, and new metagenomic methods allow direct analysis of complex samples.

Geomfinder: a multi-feature identifier of similar three-dimensional protein patterns: a ligand-independent approach.

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Núñez-Vivanco, Gabriel; Valdés-Jiménez, Alejandro; Besoaín, Felipe; Reyes-Parada, Miguel

2016-01-01

Since the structure of proteins is more conserved than the sequence, the identification of conserved three-dimensional (3D) patterns among a set of proteins, can be important for protein function prediction, protein clustering, drug discovery and the establishment of evolutionary relationships. Thus, several computational applications to identify, describe and compare 3D patterns (or motifs) have been developed. Often, these tools consider a 3D pattern as that described by the residues surrounding co-crystallized/docked ligands available from X-ray crystal structures or homology models. Nevertheless, many of the protein structures stored in public databases do not provide information about the location and characteristics of ligand binding sites and/or other important 3D patterns such as allosteric sites, enzyme-cofactor interaction motifs, etc. This makes necessary the development of new ligand-independent methods to search and compare 3D patterns in all available protein structures. Here we introduce Geomfinder, an intuitive, flexible, alignment-free and ligand-independent web server for detailed estimation of similarities between all pairs of 3D patterns detected in any two given protein structures. We used around 1100 protein structures to form pairs of proteins which were assessed with Geomfinder. In these analyses each protein was considered in only one pair (e.g. in a subset of 100 different proteins, 50 pairs of proteins can be defined). Thus: (a) Geomfinder detected identical pairs of 3D patterns in a series of monoamine oxidase-B structures, which corresponded to the effectively similar ligand binding sites at these proteins; (b) we identified structural similarities among pairs of protein structures which are targets of compounds such as acarbose, benzamidine, adenosine triphosphate and pyridoxal phosphate; these similar 3D patterns are not detected using sequence-based methods; (c) the detailed evaluation of three specific cases showed the versatility

SPARSE: quadratic time simultaneous alignment and folding of RNAs without sequence-based heuristics.

Science.gov (United States)

Will, Sebastian; Otto, Christina; Miladi, Milad; Möhl, Mathias; Backofen, Rolf

2015-08-01

RNA-Seq experiments have revealed a multitude of novel ncRNAs. The gold standard for their analysis based on simultaneous alignment and folding suffers from extreme time complexity of [Formula: see text]. Subsequently, numerous faster 'Sankoff-style' approaches have been suggested. Commonly, the performance of such methods relies on sequence-based heuristics that restrict the search space to optimal or near-optimal sequence alignments; however, the accuracy of sequence-based methods breaks down for RNAs with sequence identities below 60%. Alignment approaches like LocARNA that do not require sequence-based heuristics, have been limited to high complexity ([Formula: see text] quartic time). Breaking this barrier, we introduce the novel Sankoff-style algorithm 'sparsified prediction and alignment of RNAs based on their structure ensembles (SPARSE)', which runs in quadratic time without sequence-based heuristics. To achieve this low complexity, on par with sequence alignment algorithms, SPARSE features strong sparsification based on structural properties of the RNA ensembles. Following PMcomp, SPARSE gains further speed-up from lightweight energy computation. Although all existing lightweight Sankoff-style methods restrict Sankoff's original model by disallowing loop deletions and insertions, SPARSE transfers the Sankoff algorithm to the lightweight energy model completely for the first time. Compared with LocARNA, SPARSE achieves similar alignment and better folding quality in significantly less time (speedup: 3.7). At similar run-time, it aligns low sequence identity instances substantially more accurate than RAF, which uses sequence-based heuristics. © The Author 2015. Published by Oxford University Press.

Genome Sequence of the Biocontrol Strain Pseudomonas fluorescens F113

Science.gov (United States)

Redondo-Nieto, Miguel; Barret, Matthieu; Morrisey, John P.; Germaine, Kieran; Martínez-Granero, Francisco; Barahona, Emma; Navazo, Ana; Sánchez-Contreras, María; Moynihan, Jennifer A.; Giddens, Stephen R.; Coppoolse, Eric R.; Muriel, Candela; Stiekema, Willem J.; Rainey, Paul B.; Dowling, David; O'Gara, Fergal; Martín, Marta

2012-01-01

Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) that has biocontrol activity against fungal plant pathogens and is a model for rhizosphere colonization. Here, we present its complete genome sequence, which shows that besides a core genome very similar to those of other strains sequenced within this species, F113 possesses a wide array of genes encoding specialized functions for thriving in the rhizosphere and interacting with eukaryotic organisms. PMID:22328765

Draft Genome Sequence of Lactobacillus rhamnosus 2166.

OpenAIRE

Karlyshev, Andrey V.; Melnikov, Vyacheslav G.; Kosarev, Igor V.; Abramov, Vyacheslav M.

2014-01-01

In this report, we present a draft sequence of the genome of Lactobacillus rhamnosus strain 2166, a potential novel probiotic. Genome annotation and read mapping onto a reference genome of L. rhamnosus strain GG allowed for the identification of the differences and similarities in the genomic contents and gene arrangements of these strains.

Nucleotide sequence of a cDNA coding for the amino-terminal region of human prepro. alpha. 1(III) collagen

Energy Technology Data Exchange (ETDEWEB)

Toman, P D; Ricca, G A [Rorer Biotechnology, Inc., Springfield, VA (USA); de Crombrugghe, B [National Institutes of Health, Bethesda, MD (USA)

1988-07-25

Type III Collagen is synthesized in a variety of tissues as a precursor macromolecule containing a leader sequence, a N-propeptide, a N-telopeptide, the triple helical region, a C-telopeptide, and C-propeptide. To further characterize the human type III collagen precursor, a human placental cDNA library was constructed in gt11 using an oligonucleotide derived from a partial cDNA sequence corresponding to the carboxy-terminal part of the 1(III) collagen. A cDNA was identified which contains the leader sequence, the N-propeptide and N-telopeptide regions. The DNA sequence of these regions are presented here. The triple helical, C-telopeptide and C-propeptide amino acid sequence for human type III collagen has been determined previously. A comparison of the human amino acid sequence with mouse, chicken, and calf sequence shows 81%, 81%, and 92% similarity, respectively. At the DNA level, the sequence similarity between human and mouse or chicken type III collagen sequences in this area is 82% and 77%, respectively.

Comparison of the Diversity of Basidiomycetes from Dead Wood of the Manchurian fir (Abies holophylla) as Evaluated by Fruiting Body Collection, Mycelial Isolation, and 454 Sequencing.

Science.gov (United States)

Jang, Yeongseon; Jang, Seokyoon; Min, Mihee; Hong, Joo-Hyun; Lee, Hanbyul; Lee, Hwanhwi; Lim, Young Woon; Kim, Jae-Jin

2015-10-01

In this study, three different methods (fruiting body collection, mycelial isolation, and 454 sequencing) were implemented to determine the diversity of wood-inhabiting basidiomycetes from dead Manchurian fir (Abies holophylla). The three methods recovered similar species richness (26 species from fruiting bodies, 32 species from mycelia, and 32 species from 454 sequencing), but Fisher's alpha, Shannon-Wiener, Simpson's diversity indices of fungal communities indicated fruiting body collection and mycelial isolation displayed higher diversity compared with 454 sequencing. In total, 75 wood-inhabiting basidiomycetes were detected. The most frequently observed species were Heterobasidion orientale (fruiting body collection), Bjerkandera adusta (mycelial isolation), and Trichaptum fusco-violaceum (454 sequencing). Only two species, Hymenochaete yasudae and Hypochnicium karstenii, were detected by all three methods. This result indicated that Manchurian fir harbors a diverse basidiomycetous fungal community and for complete estimation of fungal diversity, multiple methods should be used. Further studies are required to understand their ecology in the context of forest ecosystems.

Average is Boring: How Similarity Kills a Meme's Success

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Coscia, Michele

2014-09-01

Every day we are exposed to different ideas, or memes, competing with each other for our attention. Previous research explained popularity and persistence heterogeneity of memes by assuming them in competition for limited attention resources, distributed in a heterogeneous social network. Little has been said about what characteristics make a specific meme more likely to be successful. We propose a similarity-based explanation: memes with higher similarity to other memes have a significant disadvantage in their potential popularity. We employ a meme similarity measure based on semantic text analysis and computer vision to prove that a meme is more likely to be successful and to thrive if its characteristics make it unique. Our results show that indeed successful memes are located in the periphery of the meme similarity space and that our similarity measure is a promising predictor of a meme success.

Comparison of double-locus sequence typing (DLST) and multilocus sequence typing (MLST) for the investigation of Pseudomonas aeruginosa populations.

Science.gov (United States)

Cholley, Pascal; Stojanov, Milos; Hocquet, Didier; Thouverez, Michelle; Bertrand, Xavier; Blanc, Dominique S

2015-08-01

Reliable molecular typing methods are necessary to investigate the epidemiology of bacterial pathogens. Reference methods such as multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) are costly and time consuming. Here, we compared our newly developed double-locus sequence typing (DLST) method for Pseudomonas aeruginosa to MLST and PFGE on a collection of 281 isolates. DLST was as discriminatory as MLST and was able to recognize "high-risk" epidemic clones. Both methods were highly congruent. Not surprisingly, a higher discriminatory power was observed with PFGE. In conclusion, being a simple method (single-strand sequencing of only 2 loci), DLST is valuable as a first-line typing tool for epidemiological investigations of P. aeruginosa. Coupled to a more discriminant method like PFGE or whole genome sequencing, it might represent an efficient typing strategy to investigate or prevent outbreaks. Copyright © 2015 Elsevier Inc. All rights reserved.

Molecular Analysis of Methanogen Richness in Landfill and Marshland Targeting 16S rDNA Sequences.

Science.gov (United States)

Yadav, Shailendra; Kundu, Sharbadeb; Ghosh, Sankar K; Maitra, S S

2015-01-01

Methanogens, a key contributor in global carbon cycling, methane emission, and alternative energy production, generate methane gas via anaerobic digestion of organic matter. The methane emission potential depends upon methanogenic diversity and activity. Since they are anaerobes and difficult to isolate and culture, their diversity present in the landfill sites of Delhi and marshlands of Southern Assam, India, was analyzed using molecular techniques like 16S rDNA sequencing, DGGE, and qPCR. The sequencing results indicated the presence of methanogens belonging to the seventh order and also the order Methanomicrobiales in the Ghazipur and Bhalsawa landfill sites of Delhi. Sequences, related to the phyla Crenarchaeota (thermophilic) and Thaumarchaeota (mesophilic), were detected from marshland sites of Southern Assam, India. Jaccard analysis of DGGE gel using Gel2K showed three main clusters depending on the number and similarity of band patterns. The copy number analysis of hydrogenotrophic methanogens using qPCR indicates higher abundance in landfill sites of Delhi as compared to the marshlands of Southern Assam. The knowledge about "methanogenic archaea composition" and "abundance" in the contrasting ecosystems like "landfill" and "marshland" may reorient our understanding of the Archaea inhabitants. This study could shed light on the relationship between methane-dynamics and the global warming process.

Molecular Analysis of Methanogen Richness in Landfill and Marshland Targeting 16S rDNA Sequences

Directory of Open Access Journals (Sweden)

Shailendra Yadav

2015-01-01

Full Text Available Methanogens, a key contributor in global carbon cycling, methane emission, and alternative energy production, generate methane gas via anaerobic digestion of organic matter. The methane emission potential depends upon methanogenic diversity and activity. Since they are anaerobes and difficult to isolate and culture, their diversity present in the landfill sites of Delhi and marshlands of Southern Assam, India, was analyzed using molecular techniques like 16S rDNA sequencing, DGGE, and qPCR. The sequencing results indicated the presence of methanogens belonging to the seventh order and also the order Methanomicrobiales in the Ghazipur and Bhalsawa landfill sites of Delhi. Sequences, related to the phyla Crenarchaeota (thermophilic and Thaumarchaeota (mesophilic, were detected from marshland sites of Southern Assam, India. Jaccard analysis of DGGE gel using Gel2K showed three main clusters depending on the number and similarity of band patterns. The copy number analysis of hydrogenotrophic methanogens using qPCR indicates higher abundance in landfill sites of Delhi as compared to the marshlands of Southern Assam. The knowledge about “methanogenic archaea composition” and “abundance” in the contrasting ecosystems like “landfill” and “marshland” may reorient our understanding of the Archaea inhabitants. This study could shed light on the relationship between methane-dynamics and the global warming process.

Identification and chromosomal distribution of copia-like retrotransposon sequences in the coffee (Coffea L. genome

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Juan-Carlos Herrera

2013-12-01

Full Text Available The presence of copia-like transposable elements in seven coffee (Coffea sp. species, including the cultivated Coffea arabica, was investigated. The highly conserved domains of the reverse transcriptase (RT present in the copia retrotransposons were amplified by PCR using degenerated primers. Fragments of roughly 300 bp were obtained and the nucleotide sequence was determined for 36 clones, 19 of which showed good quality. The deduced amino acid sequences were compared by multiple alignment analysis. The data suggested two distinct coffee RT groups, designated as CRTG1 and CRTG2. The sequence identities among the groups ranged from 52 to 60% for CRTG1 and 74 to 85% for CRTG2. The multiple alignment analysis revealed that some of the clones in CRTG1 were closely related to the representative elements present in other plant species such as Brassica napus, Populus ciliata and Picea abis. Furthermore, the chromosomal localization of the RT domains in C. arabica and their putative ancestors was investigated by fluorescence in situ hybridization (FISH analysis. FISH signals were observed throughout the chromosomes following a similar dispersed pattern with some localized regions exhibiting higher concentrations of those elements, providing new evidence of their relative conservation and stability in the coffee genome

Sequence similarity between the viral cp gene and the transgene in transgenic papayas Similaridade de seqüência entre o gene cp do vírus e do transgene presente em mamoeiros transgênicos

Directory of Open Access Journals (Sweden)

Manoel Teixeira Souza Júnior

2005-05-01

Full Text Available The Papaya ringspot virus (PRSV coat protein transgene present in 'Rainbow' and 'SunUp' papayas disclose high sequence similarity (>89% to the cp gene from PRSV BR and TH. Despite this, both isolates are able to break down the resistance in 'Rainbow', while only the latter is able to do so in 'SunUp'. The objective of this work was to evaluate the degree of sequence similarity between the cp gene in the challenge isolate and the cp transgene in transgenic papayas resistant to PRSV. The production of a hybrid virus containing the genome backbone of PRSV HA up to the Apa I site in the NIb gene, and downstream from there, the sequence of PRSV TH was undertaken. This hybrid virus, PRSV HA/TH, was obtained and used to challenge 'Rainbow', 'SunUp', and an R2 population derived from line 63-1, all resistant to PRSV HA. PRSV HA/TH broke down the resistance in both papaya varieties and in the 63-1 population, demonstrating that sequence similarity is a major factor in the mechanism of resistance used by transgenic papayas expressing the cp gene. A comparative analysis of the cp gene present in line 55-1 and 63-1-derived transgenic plants and in PRSV HA, BR, and TH was also performed.O gene da capa protéica (cp do vírus da mancha anelar do mamoeiro (Papaya ringspot virus, PRSV, presente nos mamoeiros 'Rainbow' e 'SunUp', tem alta similaridade de seqüência (>89% com o gene cp dos isolados PRSV BR e TH. Apesar deste alto grau de similaridade, ambos isolados são capazes de quebrar a resistência observada em 'Rainbow', ao passo que TH quebra a resistência em 'SunUp'. O objetivo deste trabalho foi avaliar o grau de similaridade de seqüência entre o gene cp do vírus desafiante e do transgene em mamoeiros transgênicos resistentes a PRSV. Produziu-se um vírus híbrido contendo o genoma do isolado PRSV HA até o sítio de restrição Apa I no gene NIb, e, a partir deste ponto, este vírus continha o genoma do isolado PRSV TH. PRSV HA/TH foi utilizado

Comparison of PCR-RFLP pattern with sequencing analysis of the ITS region of Hyrcanain\\'s Tilia

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Hamed Yousefzadeh

2014-01-01

T. hyrcana and T. rubra from Hyrcanian's origin, but it could not separate T. begonifloia from the other hyrcanian species. In this respect, derived results were similar to sequencing one. In conclusion, with regard to less expensive and less time consuming PCR-RFLP technique and high similarity between its result with sequencing, we recommend this method as a simple and economical method with relatively high efficiency studding plant phylogeny.

Domain similarity based orthology detection

OpenAIRE

Bitard-Feildel, Tristan; Kemena, Carsten; Greenwood, Jenny M; Bornberg-Bauer, Erich

2015-01-01

Background Orthologous protein detection software mostly uses pairwise comparisons of amino-acid sequences to assert whether two proteins are orthologous or not. Accordingly, when the number of sequences for comparison increases, the number of comparisons to compute grows in a quadratic order. A current challenge of bioinformatic research, especially when taking into account the increasing number of sequenced organisms available, is to make this ever-growing number of comparisons computationa...

Cryptographic pseudo-random sequences from the chaotic Hénon ...

Indian Academy of Sciences (India)

2-dimensional chaotic maps for the generation of pseudorandom sequences. 3. ... map. Consider the bit-stream Bx formed by choosing every Pth bit of Sx, ... Similarly, the probability of the linear complexity C assuming the value c(c < N) when.

New similarity of triangular fuzzy number and its application.

Science.gov (United States)

Zhang, Xixiang; Ma, Weimin; Chen, Liping

2014-01-01

The similarity of triangular fuzzy numbers is an important metric for application of it. There exist several approaches to measure similarity of triangular fuzzy numbers. However, some of them are opt to be large. To make the similarity well distributed, a new method SIAM (Shape's Indifferent Area and Midpoint) to measure triangular fuzzy number is put forward, which takes the shape's indifferent area and midpoint of two triangular fuzzy numbers into consideration. Comparison with other similarity measurements shows the effectiveness of the proposed method. Then, it is applied to collaborative filtering recommendation to measure users' similarity. A collaborative filtering case is used to illustrate users' similarity based on cloud model and triangular fuzzy number; the result indicates that users' similarity based on triangular fuzzy number can obtain better discrimination. Finally, a simulated collaborative filtering recommendation system is developed which uses cloud model and triangular fuzzy number to express users' comprehensive evaluation on items, and result shows that the accuracy of collaborative filtering recommendation based on triangular fuzzy number is higher.

The Biomolecule Sequencer Project: Nanopore Sequencing as a Dual-Use Tool for Crew Health and Astrobiology Investigations

Science.gov (United States)

John, K. K.; Botkin, D. S.; Burton, A. S.; Castro-Wallace, S. L.; Chaput, J. D.; Dworkin, J. P.; Lehman, N.; Lupisella, M. L.; Mason, C. E.; Smith, D. J.;

Insights into Protein Sequence and Structure-Derived Features Mediating 3D Domain Swapping Mechanism using Support Vector Machine Based Approach

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Khader Shameer

2010-06-01

Full Text Available 3-dimensional domain swapping is a mechanism where two or more protein molecules form higher order oligomers by exchanging identical or similar subunits. Recently, this phenomenon has received much attention in the context of prions and neuro-degenerative diseases, due to its role in the functional regulation, formation of higher oligomers, protein misfolding, aggregation etc. While 3-dimensional domain swap mechanism can be detected from three-dimensional structures, it remains a formidable challenge to derive common sequence or structural patterns from proteins involved in swapping. We have developed a SVM-based classifier to predict domain swapping events using a set of features derived from sequence and structural data. The SVM classifier was trained on features derived from 150 proteins reported to be involved in 3D domain swapping and 150 proteins not known to be involved in swapped conformation or related to proteins involved in swapping phenomenon. The testing was performed using 63 proteins from the positive dataset and 63 proteins from the negative dataset. We obtained 76.33% accuracy from training and 73.81% accuracy from testing. Due to high diversity in the sequence, structure and functions of proteins involved in domain swapping, availability of such an algorithm to predict swapping events from sequence and structure-derived features will be an initial step towards identification of more putative proteins that may be involved in swapping or proteins involved in deposition disease. Further, the top features emerging in our feature selection method may be analysed further to understand their roles in the mechanism of domain swapping.

Determining and comparing protein function in Bacterial genome sequences

DEFF Research Database (Denmark)

Vesth, Tammi Camilla

of this class have very little homology to other known genomes making functional annotation based on sequence similarity very difficult. Inspired in part by this analysis, an approach for comparative functional annotation was created based public sequenced genomes, CMGfunc. Functionally related groups......In November 2013, there was around 21.000 different prokaryotic genomes sequenced and publicly available, and the number is growing daily with another 20.000 or more genomes expected to be sequenced and deposited by the end of 2014. An important part of the analysis of this data is the functional...... annotation of genes – the descriptions assigned to genes that describe the likely function of the encoded proteins. This process is limited by several factors, including the definition of a function which can be more or less specific as well as how many genes can actually be assigned a function based...

Comparative Genomics in Switchgrass Using 61,585 High-Quality Expressed Sequence Tags

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Christian M. Tobias

2008-11-01

Full Text Available The development of genomic resources for switchgrass ( L., a perennial NAD-malic enzyme type C grass, is required to enable molecular breeding and biotechnological approaches for improving its value as a forage and bioenergy crop. Expressed sequence tag (EST sequencing is one method that can quickly sample gene inventories and produce data suitable for marker development or analysis of tissue-specific patterns of expression. Toward this goal, three cDNA libraries from callus, crown, and seedling tissues of ‘Kanlow’ switchgrass were end-sequenced to generate a total of 61,585 high-quality ESTs from 36,565 separate clones. Seventy-three percent of the assembled consensus sequences could be aligned with the sorghum [ (L. Moench] genome at a -value of <1 × 10, indicating a high degree of similarity. Sixty-five percent of the ESTs matched with gene ontology molecular terms, and 3.3% of the sequences were matched with genes that play potential roles in cell-wall biogenesis. The representation in the three libraries of gene families known to be associated with C photosynthesis, cellulose and β-glucan synthesis, phenylpropanoid biosynthesis, and peroxidase activity indicated likely roles for individual family members. Pairwise comparisons of synonymous codon substitutions were used to assess genome sequence diversity and indicated an overall similarity between the two genome copies present in the tetraploid. Identification of EST–simple sequence repeat markers and amplification on two individual parents of a mapping population yielded an average of 2.18 amplicons per individual, and 35% of the markers produced fragment length polymorphisms.

Evaluation of ddRADseq for reduced representation metagenome sequencing

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Michael Y. Liu

2017-09-01

Full Text Available Background Profiling of microbial communities via metagenomic shotgun sequencing has enabled researches to gain unprecedented insight into microbial community structure and the functional roles of community members. This study describes a method and basic analysis for a metagenomic adaptation of the double digest restriction site associated DNA sequencing (ddRADseq protocol for reduced representation metagenome profiling. Methods This technique takes advantage of the sequence specificity of restriction endonucleases to construct an Illumina-compatible sequencing library containing DNA fragments that are between a pair of restriction sites located within close proximity. This results in a reduced sequencing library with coverage breadth that can be tuned by size selection. We assessed the performance of the metagenomic ddRADseq approach by applying the full method to human stool samples and generating sequence data. Results The ddRADseq data yields a similar estimate of community taxonomic profile as obtained from shotgun metagenome sequencing of the same human stool samples. No obvious bias with respect to genomic G + C content and the estimated relative species abundance was detected. Discussion Although ddRADseq does introduce some bias in taxonomic representation, the bias is likely to be small relative to DNA extraction bias. ddRADseq appears feasible and could have value as a tool for metagenome-wide association studies.

UPF201 Archaeal Specific Family Members Reveals Structural Similarity to RNA-Binding Proteins but Low Likelihood for RNA-Binding Function

Energy Technology Data Exchange (ETDEWEB)

Rao, K.N.; Swaminathan, S.; Burley, S. K.

2008-12-11

We have determined X-ray crystal structures of four members of an archaeal specific family of proteins of unknown function (UPF0201; Pfam classification: DUF54) to advance our understanding of the genetic repertoire of archaea. Despite low pairwise amino acid sequence identities (10-40%) and the absence of conserved sequence motifs, the three-dimensional structures of these proteins are remarkably similar to one another. Their common polypeptide chain fold, encompassing a five-stranded antiparallel {beta}-sheet and five {alpha}-helices, proved to be quite unexpectedly similar to that of the RRM-type RNA-binding domain of the ribosomal L5 protein, which is responsible for binding the 5S- rRNA. Structure-based sequence alignments enabled construction of a phylogenetic tree relating UPF0201 family members to L5 ribosomal proteins and other structurally similar RNA binding proteins, thereby expanding our understanding of the evolutionary purview of the RRM superfamily. Analyses of the surfaces of these newly determined UPF0201 structures suggest that they probably do not function as RNA binding proteins, and that this domain specific family of proteins has acquired a novel function in archaebacteria, which awaits experimental elucidation.

Expression Pattern Similarities Support the Prediction of Orthologs Retaining Common Functions after Gene Duplication Events1[OPEN

Science.gov (United States)

Haberer, Georg; Panda, Arup; Das Laha, Shayani; Ghosh, Tapas Chandra; Schäffner, Anton R.

2016-01-01

The identification of functionally equivalent, orthologous genes (functional orthologs) across genomes is necessary for accurate transfer of experimental knowledge from well-characterized organisms to others. This frequently relies on automated, coding sequence-based approaches such as OrthoMCL, Inparanoid, and KOG, which usually work well for one-to-one homologous states. However, this strategy does not reliably work for plants due to the occurrence of extensive gene/genome duplication. Frequently, for one query gene, multiple orthologous genes are predicted in the other genome, and it is not clear a priori from sequence comparison and similarity which one preserves the ancestral function. We have studied 11 organ-dependent and stress-induced gene expression patterns of 286 Arabidopsis lyrata duplicated gene groups and compared them with the respective Arabidopsis (Arabidopsis thaliana) genes to predict putative expressologs and nonexpressologs based on gene expression similarity. Promoter sequence divergence as an additional tool to substantiate functional orthology only partially overlapped with expressolog classification. By cloning eight A. lyrata homologs and complementing them in the respective four Arabidopsis loss-of-function mutants, we experimentally proved that predicted expressologs are indeed functional orthologs, while nonexpressologs or nonfunctionalized orthologs are not. Our study demonstrates that even a small set of gene expression data in addition to sequence homologies are instrumental in the assignment of functional orthologs in the presence of multiple orthologs. PMID:27303025

Similarity transformed coupled cluster response (ST-CCR) theory--a time-dependent similarity transformed equation-of-motion coupled cluster (STEOM-CC) approach.

Science.gov (United States)

Landau, Arie

2013-07-07

This paper presents a new method for calculating spectroscopic properties in the framework of response theory utilizing a sequence of similarity transformations (STs). The STs are preformed using the coupled cluster (CC) and Fock-space coupled cluster operators. The linear and quadratic response functions of the new similarity transformed CC response (ST-CCR) method are derived. The poles of the linear response yield excitation-energy (EE) expressions identical to the ones in the similarity transformed equation-of-motion coupled cluster (STEOM-CC) approach. ST-CCR and STEOM-CC complement each other, in analogy to the complementarity of CC response (CCR) and equation-of-motion coupled cluster (EOM-CC). ST-CCR/STEOM-CC and CCR/EOM-CC yield size-extensive and size-intensive EEs, respectively. Other electronic-properties, e.g., transition dipole strengths, are also size-extensive within ST-CCR, in contrast to STEOM-CC. Moreover, analysis suggests that in comparison with CCR, the ST-CCR expressions may be confined to a smaller subspace, however, the precise scope of the truncation can only be determined numerically. In addition, reformulation of the time-independent STEOM-CC using the same parameterization as in ST-CCR, as well as an efficient truncation scheme, is presented. The shown convergence of the time-dependent and time-independent expressions displays the completeness of the presented formalism.

Zonadhesin D3-Polypeptides Vary among Species but Are Similar in Equus Species Capable of Interbreeding1

Science.gov (United States)

Tardif, Steve; Brady, Heidi A.; Breazeale, Kelly R.; Bi, Ming; Thompson, Leslie D.; Bruemmer, Jason E.; Bailey, Laura B.; Hardy, Daniel M.

2009-01-01

Zonadhesin is a rapidly evolving protein in the sperm acrosome that confers species specificity to sperm-zona pellucida adhesion. Though structural variation in zonadhesin likely contributes to its species-specific function, the protein has not previously been characterized in organisms capable of interbreeding. Here we compared properties of zonadhesin in several animals, including the horse (Equus caballus), donkey (E. asinus), and Grevy's zebra (E. grevyi) to determine if variation in zonadhesin correlates with ability of gametes to cross-fertilize. Zonadhesin localized to the apical acrosomes of spermatozoa from all three Equus species, similar to its localization in other animals. Likewise, in horse and donkey testis, zonadhesin was detected only in germ cells, first in the acrosomal granule of round spermatids and then in the developing acrosomes of elongating spermatids. Among non-Equus species, D3-domain polypeptides of mature, processed zonadhesin varied markedly in size and detergent solubility. However, zonadhesin D3-domain polypeptides in horse, donkey, and zebra spermatozoa exhibited identical electrophoretic mobility and detergent solubility. Equus zonadhesin D3-polypeptides (p110/p80 doublet) were most similar in size to porcine and bovine zonadhesin D3-polypeptides (p105). Sequence comparisons revealed that the horse zonadhesin precursor's domain content and arrangement are similar to those of zonadhesin from other large animals. Partial sequences of horse and donkey zonadhesin were much more similar to each other (>99% identity) than they were to orthologous sequences of human, pig, rabbit, and mouse zonadhesin (52%–72% identity). We conclude that conservation of zonadhesin D3-polypeptide properties correlates with ability of Equus species to interbreed. PMID:19794156

Easy and accurate reconstruction of whole HIV genomes from short-read sequence data with shiver

Science.gov (United States)

Blanquart, François; Golubchik, Tanya; Gall, Astrid; Bakker, Margreet; Bezemer, Daniela; Croucher, Nicholas J; Hall, Matthew; Hillebregt, Mariska; Ratmann, Oliver; Albert, Jan; Bannert, Norbert; Fellay, Jacques; Fransen, Katrien; Gourlay, Annabelle; Grabowski, M Kate; Gunsenheimer-Bartmeyer, Barbara; Günthard, Huldrych F; Kivelä, Pia; Kouyos, Roger; Laeyendecker, Oliver; Liitsola, Kirsi; Meyer, Laurence; Porter, Kholoud; Ristola, Matti; van Sighem, Ard; Cornelissen, Marion; Kellam, Paul; Reiss, Peter

2018-01-01

Abstract Studying the evolution of viruses and their molecular epidemiology relies on accurate viral sequence data, so that small differences between similar viruses can be meaningfully interpreted. Despite its higher throughput and more detailed minority variant data, next-generation sequencing has yet to be widely adopted for HIV. The difficulty of accurately reconstructing the consensus sequence of a quasispecies from reads (short fragments of DNA) in the presence of large between- and within-host diversity, including frequent indels, may have presented a barrier. In particular, mapping (aligning) reads to a reference sequence leads to biased loss of information; this bias can distort epidemiological and evolutionary conclusions. De novo assembly avoids this bias by aligning the reads to themselves, producing a set of sequences called contigs. However contigs provide only a partial summary of the reads, misassembly may result in their having an incorrect structure, and no information is available at parts of the genome where contigs could not be assembled. To address these problems we developed the tool shiver to pre-process reads for quality and contamination, then map them to a reference tailored to the sample using corrected contigs supplemented with the user’s choice of existing reference sequences. Run with two commands per sample, it can easily be used for large heterogeneous data sets. We used shiver to reconstruct the consensus sequence and minority variant information from paired-end short-read whole-genome data produced with the Illumina platform, for sixty-five existing publicly available samples and fifty new samples. We show the systematic superiority of mapping to shiver’s constructed reference compared with mapping the same reads to the closest of 3,249 real references: median values of 13 bases called differently and more accurately, 0 bases called differently and less accurately, and 205 bases of missing sequence recovered. We also

16S ribosomal RNA sequence analysis for determination of phylogenetic relationship among methylotrophs.

Science.gov (United States)

Tsuji, K; Tsien, H C; Hanson, R S; DePalma, S R; Scholtz, R; LaRoche, S

1990-01-01

16S ribosomal RNAs (rRNA) of 12 methylotrophic bacteria have been almost completely sequenced to establish their phylogenetic relationships. Methylotrophs that are physiologically related are phylogenetically diverse and are scattered among the purple eubacteria (class Proteobacteria). Group I methylotrophs can be classified in the beta- and the gamma-subdivisions and group II methylotrophs in the alpha-subdivision of the purple eubacteria, respectively. Pink-pigmented facultative and non-pigmented obligate group II methylotrophs form two distinctly separate branches within the alpha-subdivision. The secondary structures of the 16S rRNA sequences of 'Methylocystis parvus' strain OBBP, 'Methylosinus trichosporium' strain OB3b, 'Methylosporovibrio methanica' strain 81Z and Hyphomicrobium sp. strain DM2 are similar, and these non-pigmented obligate group II methylotrophs form one tight cluster in the alpha-subdivision. The pink-pigmented facultative methylotrophs, Methylobacterium extorquens strain AM1, Methylobacterium sp. strain DM4 and Methylobacterium organophilum strain XX form another cluster within the alpha-subdivision. Although similar in phenotypic characteristics, Methylobacterium organophilum strain XX and Methylobacterium extorquens strain AM1 are clearly distinguishable by their 16S rRNA sequences. The group I methylotrophs, Methylophilus methylotrophus strain AS1 and methylotrophic species DM11, which do not utilize methane, are similar in 16S rRNA sequence to bacteria in the beta-subdivision. The methane-utilizing, obligate group I methanotrophs, Methylococcus capsulatus strain BATH and Methylomonas methanica, are placed in the gamma-subdivision. The results demonstrate that it is possible to distinguish and classify the methylotrophic bacteria using 16S rRNA sequence analysis.

SPARSE: quadratic time simultaneous alignment and folding of RNAs without sequence-based heuristics

Science.gov (United States)

Will, Sebastian; Otto, Christina; Miladi, Milad; Möhl, Mathias; Backofen, Rolf

2015-01-01

Motivation: RNA-Seq experiments have revealed a multitude of novel ncRNAs. The gold standard for their analysis based on simultaneous alignment and folding suffers from extreme time complexity of O(n6). Subsequently, numerous faster ‘Sankoff-style’ approaches have been suggested. Commonly, the performance of such methods relies on sequence-based heuristics that restrict the search space to optimal or near-optimal sequence alignments; however, the accuracy of sequence-based methods breaks down for RNAs with sequence identities below 60%. Alignment approaches like LocARNA that do not require sequence-based heuristics, have been limited to high complexity (≥ quartic time). Results: Breaking this barrier, we introduce the novel Sankoff-style algorithm ‘sparsified prediction and alignment of RNAs based on their structure ensembles (SPARSE)’, which runs in quadratic time without sequence-based heuristics. To achieve this low complexity, on par with sequence alignment algorithms, SPARSE features strong sparsification based on structural properties of the RNA ensembles. Following PMcomp, SPARSE gains further speed-up from lightweight energy computation. Although all existing lightweight Sankoff-style methods restrict Sankoff’s original model by disallowing loop deletions and insertions, SPARSE transfers the Sankoff algorithm to the lightweight energy model completely for the first time. Compared with LocARNA, SPARSE achieves similar alignment and better folding quality in significantly less time (speedup: 3.7). At similar run-time, it aligns low sequence identity instances substantially more accurate than RAF, which uses sequence-based heuristics. Availability and implementation: SPARSE is freely available at http://www.bioinf.uni-freiburg.de/Software/SPARSE. Contact: backofen@informatik.uni-freiburg.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25838465

Nucleotide sequence of tomato ringspot virus RNA-2.

Science.gov (United States)

Rott, M E; Tremaine, J H; Rochon, D M

1991-07-01

The sequence of tomato ringspot virus (TomRSV) RNA-2 has been determined. It is 7273 nucleotides in length excluding the 3' poly(A) tail and contains a single long open reading frame (ORF) of 5646 nucleotides in the positive sense beginning at position 78 and terminating at position 5723. A second in-frame AUG at position 441 is in a more favourable context for initiation of translation and may act as a site for initiation of translation. The TomRSV RNA-2 3' noncoding region is 1550 nucleotides in length. The coat protein is located in the C-terminal region of the large polypeptide and shows significant but limited amino acid sequence similarity to the putative coat proteins of the nepoviruses tomato black ring (TBRV), Hungarian grapevine chrome mosaic (GCMV) and grapevine fanleaf (GFLV). Comparisons of the coding and non-coding regions of TomRSV RNA-2 and the RNA components of TBRV, GCMV, GFLV and the comovirus cowpea mosaic virus revealed significant similarity for over 300 amino acids between the coding region immediately to the N-terminal side of the putative coat proteins of TomRSV and GFLV; very little similarity could be detected among the non-coding regions of TomRSV and any of these viruses.

The Role of Heterologous Chloroplast Sequence Elements in Transgene Integration and Expression1[W][OA

Science.gov (United States)

Ruhlman, Tracey; Verma, Dheeraj; Samson, Nalapalli; Daniell, Henry

2010-01-01

Heterologous regulatory elements and flanking sequences have been used in chloroplast transformation of several crop species, but their roles and mechanisms have not yet been investigated. Nucleotide sequence identity in the photosystem II protein D1 (psbA) upstream region is 59% across all taxa; similar variation was consistent across all genes and taxa examined. Secondary structure and predicted Gibbs free energy values of the psbA 5′ untranslated region (UTR) among different families reflected this variation. Therefore, chloroplast transformation vectors were made for tobacco (Nicotiana tabacum) and lettuce (Lactuca sativa), with endogenous (Nt-Nt, Ls-Ls) or heterologous (Nt-Ls, Ls-Nt) psbA promoter, 5′ UTR and 3′ UTR, regulating expression of the anthrax protective antigen (PA) or human proinsulin (Pins) fused with the cholera toxin B-subunit (CTB). Unique lettuce flanking sequences were completely eliminated during homologous recombination in the transplastomic tobacco genomes but not unique tobacco sequences. Nt-Ls or Ls-Nt transplastomic lines showed reduction of 80% PA and 97% CTB-Pins expression when compared with endogenous psbA regulatory elements, which accumulated up to 29.6% total soluble protein PA and 72.0% total leaf protein CTB-Pins, 2-fold higher than Rubisco. Transgene transcripts were reduced by 84% in Ls-Nt-CTB-Pins and by 72% in Nt-Ls-PA lines. Transcripts containing endogenous 5′ UTR were stabilized in nonpolysomal fractions. Stromal RNA-binding proteins were preferentially associated with endogenous psbA 5′ UTR. A rapid and reproducible regeneration system was developed for lettuce commercial cultivars by optimizing plant growth regulators. These findings underscore the need for sequencing complete crop chloroplast genomes, utilization of endogenous regulatory elements and flanking sequences, as well as optimization of plant growth regulators for efficient chloroplast transformation. PMID:20130101

Binning sequences using very sparse labels within a metagenome

Directory of Open Access Journals (Sweden)

Halgamuge Saman K

2008-04-01

Full Text Available Abstract Background In metagenomic studies, a process called binning is necessary to assign contigs that belong to multiple species to their respective phylogenetic groups. Most of the current methods of binning, such as BLAST, k-mer and PhyloPythia, involve assigning sequence fragments by comparing sequence similarity or sequence composition with already-sequenced genomes that are still far from comprehensive. We propose a semi-supervised seeding method for binning that does not depend on knowledge of completed genomes. Instead, it extracts the flanking sequences of highly conserved 16S rRNA from the metagenome and uses them as seeds (labels to assign other reads based on their compositional similarity. Results The proposed seeding method is implemented on an unsupervised Growing Self-Organising Map (GSOM, and called Seeded GSOM (S-GSOM. We compared it with four well-known semi-supervised learning methods in a preliminary test, separating random-length prokaryotic sequence fragments sampled from the NCBI genome database. We identified the flanking sequences of the highly conserved 16S rRNA as suitable seeds that could be used to group the sequence fragments according to their species. S-GSOM showed superior performance compared to the semi-supervised methods tested. Additionally, S-GSOM may also be used to visually identify some species that do not have seeds. The proposed method was then applied to simulated metagenomic datasets using two different confidence threshold settings and compared with PhyloPythia, k-mer and BLAST. At the reference taxonomic level Order, S-GSOM outperformed all k-mer and BLAST results and showed comparable results with PhyloPythia for each of the corresponding confidence settings, where S-GSOM performed better than PhyloPythia in the ≥ 10 reads datasets and comparable in the ≥ 8 kb benchmark tests. Conclusion In the task of binning using semi-supervised learning methods, results indicate S-GSOM to be the best of

Association studies using family pools of outcrossing crops based on allele-frequency estimates from DNA sequencing

DEFF Research Database (Denmark)

Ashraf, Bilal; Jensen, Just; Asp, Torben

2014-01-01

effect from F2-family pools was verified and it was shown that the underestimation of the allele effect is correctly described. The optimal design for an association study when sequencing budget would be fixed is obtained using large sample size and lower sequence depth, and using higher SNP density......F2 families are frequently used in breeding of outcrossing species, for instance to obtain trait measurements on plots. We propose to perform association studies by obtaining a matching “family genotype” from sequencing a pooled sample of the family, and to directly use allele frequencies computed...... (resulting in higher LD with causative mutations) and lower sequencing depth. Therefore, association studies using genotyping by sequencing are optimal and use low sequencing depth per sample. The developed framework for association studies using allele frequencies from sequencing can be modified for other...

PASSIOMA: Exploring Expressed Sequence Tags during Flower Development in Passiflora spp.

Directory of Open Access Journals (Sweden)

Lucas Cutri

2012-01-01

Full Text Available The genus Passiflora provides a remarkable example of floral complexity and diversity. The extreme variation of Passiflora flower morphologies allowed a wide range of interactions with pollinators to evolve. We used the analysis of expressed sequence tags (ESTs as an approach for the characterization of genes expressed during Passiflora reproductive development. Analyzing the Passiflora floral EST database (named PASSIOMA, we found sequences showing significant sequence similarity to genes known to be involved in reproductive development such as MADS-box genes. Some of these sequences were studied using RT-PCR and in situ hybridization confirming their expression during Passiflora flower development. The detection of these novel sequences can contribute to the development of EST-based markers for important agronomic traits as well as to the establishment of genomic tools to study the naturally occurring floral diversity among Passiflora species.

Multi-scale structural similarity index for motion detection

Directory of Open Access Journals (Sweden)

M. Abdel-Salam Nasr

2017-07-01

Full Text Available The most recent approach for measuring the image quality is the structural similarity index (SSI. This paper presents a novel algorithm based on the multi-scale structural similarity index for motion detection (MS-SSIM in videos. The MS-SSIM approach is based on modeling of image luminance, contrast and structure at multiple scales. The MS-SSIM has resulted in much better performance than the single scale SSI approach but at the cost of relatively lower processing speed. The major advantages of the presented algorithm are both: the higher detection accuracy and the quasi real-time processing speed.

Genome and Transcriptome Sequencing of the Ostreid herpesvirus 1 From Tomales Bay, California

Science.gov (United States)

Burge, C. A.; Langevin, S.; Closek, C. J.; Roberts, S. B.; Friedman, C. S.

2016-02-01

Mass mortalities of larval and seed bivalve molluscs attributed to the Ostreid herpesvirus 1 (OsHV-1) occur globally. OsHV-1 was fully sequenced and characterized as a member of the Family Malacoherpesviridae. Multiple strains of OsHV-1 exist and may vary in virulence, i.e. OsHV-1 µvar. For most global variants of OsHV-1, sequence data is limited to PCR-based sequencing of segments, including two recent genomes. In the United States, OsHV-1 is limited to detection in adjacent embayments in California, Tomales and Drakes bays. Limited DNA sequence data of OsHV-1 infecting oysters in Tomales Bay indicates the virus detected in Tomales Bay is similar but not identical to any one global variant of OsHV-1. In order to better understand both strain variation and virulence of OsHV-1 infecting oysters in Tomales Bay, we used genomic and transcriptomic sequencing. Meta-genomic sequencing (Illumina MiSeq) was conducted from infected oysters (n=4 per year) collected in 2003, 2007, and 2014, where full OsHV-1 genome sequences and low overall microbial diversity were achieved from highly infected oysters. Increased microbial diversity was detected in three of four samples sequenced from 2003, where qPCR based genome copy numbers of OsHV-1 were lower. Expression analysis (SOLiD RNA sequencing) of OsHV-1 genes expressed in oyster larvae at 24 hours post exposure revealed a nearly complete transcriptome, with several highly expressed genes, which are similar to recent transcriptomic analyses of other OsHV-1 variants. Taken together, our results indicate that genome and transcriptome sequencing may be powerful tools in understanding both strain variation and virulence of non-culturable marine viruses.

Comprehensive analysis of an Antarctic bacterial community with the adaptability of growth at higher temperatures than those in Antarctica.

Science.gov (United States)

Hosoi-Tanabe, Shoko; Zhang, Hongyan; Zhu, Daochen; Nagata, Shinichi; Ban, Syuhei; Imura, Satoshi

2010-06-01

To investigate the adaptability to higher temperatures of Antarctic microorganisms persisting in low temperature conditions for a long time, Antarctic lake samples were incubated in several selection media at 25 degrees C and 30 degrees C. The microorganisms did not grow at 30 degrees C; however, some of them grew at 25 degrees C, indicating that the bacteria in Antarctic have the ability to grow at a wide range of temperatures. Total DNA was extracted from these microorganisms and amplified using the bacteria-universal primers. The amplified fragments were cloned, and randomly selected 48 clones were sequenced. The sequenced clones showed high similarity to the alpha-subdivision of the Proteobacteria with specific affinity to the genus Agrobacterium, Caulobacter and Brevundimonas, the ss-subdivision of Proteobacteria with specific affinity to the genus Cupriavidus, and Bacillus of the phylum Firmicutes. These results showed the presence of universal genera, suggesting that the bacteria in the Antarctic lake were not specific to this environment.

DGGE and 16S rDNA sequencing analysis of bacterial communities in colon content and feces of pigs fed whole crop rice.

Science.gov (United States)

Wang, Hai-Feng; Zhu, Wei-Yun; Yao, Wen; Liu, Jian-Xin

2007-01-01

The effect of feeding whole crop rice (WCR) to growing-finishing pigs at three levels 0 (Control), 10% and 20% on bacterial communities in colon content and feces was analyzed using 16S rDNA-based techniques. Amplicons of the V6-V8 variable regions of bacterial 16S rDNA were analyzed by denaturing gradient gel electrophoresis (DGGE), cloning and sequencing. The total number of DGGE bands and Shannon index of diversity for feces samples were higher in the pigs fed WCR-containing diets compared with the control, while a decrease trend was observed in these two parameters for colon content samples with the inclusion of WCR in the diets, although statistical differences were not significant. In general, the intestinal bacterial communities were prone to form the cluster for pig fed the same diet. Feeding of WCR induced the presence of special DGGE band with the sequence showing 99% similarity to that of Lactobacillus reuteri (DSM 20016T). The sequences of seven amplicons in total nine clones showed less than 97% similarity with those of previously identified or unidentified bacteria, suggesting that most bacteria in gastrointestinal tracts have not been cultured or identified. The results suggest that the diet containing WCR did not affect the major groups of bacteria, but stimulated the growth of L. reuteri-like species.

SequenceCEROSENE: a computational method and web server to visualize spatial residue neighborhoods at the sequence level.

Science.gov (United States)

Heinke, Florian; Bittrich, Sebastian; Kaiser, Florian; Labudde, Dirk

2016-01-01

To understand the molecular function of biopolymers, studying their structural characteristics is of central importance. Graphics programs are often utilized to conceive these properties, but with the increasing number of available structures in databases or structure models produced by automated modeling frameworks this process requires assistance from tools that allow automated structure visualization. In this paper a web server and its underlying method for generating graphical sequence representations of molecular structures is presented. The method, called SequenceCEROSENE (color encoding of residues obtained by spatial neighborhood embedding), retrieves the sequence of each amino acid or nucleotide chain in a given structure and produces a color coding for each residue based on three-dimensional structure information. From this, color-highlighted sequences are obtained, where residue coloring represent three-dimensional residue locations in the structure. This color encoding thus provides a one-dimensional representation, from which spatial interactions, proximity and relations between residues or entire chains can be deduced quickly and solely from color similarity. Furthermore, additional heteroatoms and chemical compounds bound to the structure, like ligands or coenzymes, are processed and reported as well. To provide free access to SequenceCEROSENE, a web server has been implemented that allows generating color codings for structures deposited in the Protein Data Bank or structure models uploaded by the user. Besides retrieving visualizations in popular graphic formats, underlying raw data can be downloaded as well. In addition, the server provides user interactivity with generated visualizations and the three-dimensional structure in question. Color encoded sequences generated by SequenceCEROSENE can aid to quickly perceive the general characteristics of a structure of interest (or entire sets of complexes), thus supporting the researcher in the initial

Perceptions of randomness in binary sequences: Normative, heuristic, or both?

Science.gov (United States)

Reimers, Stian; Donkin, Chris; Le Pelley, Mike E

2018-03-01

When people consider a series of random binary events, such as tossing an unbiased coin and recording the sequence of heads (H) and tails (T), they tend to erroneously rate sequences with less internal structure or order (such as HTTHT) as more probable than sequences containing more structure or order (such as HHHHH). This is traditionally explained as a local representativeness effect: Participants assume that the properties of long sequences of random outcomes-such as an equal proportion of heads and tails, and little internal structure-should also apply to short sequences. However, recent theoretical work has noted that the probability of a particular sequence of say, heads and tails of length n, occurring within a larger (>n) sequence of coin flips actually differs by sequence, so P(HHHHH) rational norms based on limited experience. We test these accounts. Participants in Experiment 1 rated the likelihood of occurrence for all possible strings of 4, 5, and 6 observations in a sequence of coin flips. Judgments were better explained by representativeness in alternation rate, relative proportion of heads and tails, and sequence complexity, than by objective probabilities. Experiments 2 and 3 gave similar results using incentivized binary choice procedures. Overall the evidence suggests that participants are not sensitive to variation in objective probabilities of a sub-sequence occurring; they appear to use heuristics based on several distinct forms of representativeness. Copyright © 2017 Elsevier B.V. All rights reserved.

MODexplorer: an integrated tool for exploring protein sequence, structure and function relationships.

KAUST Repository

Kosinski, Jan; Barbato, Alessandro; Tramontano, Anna

2013-01-01

SUMMARY: MODexplorer is an integrated tool aimed at exploring the sequence, structural and functional diversity in protein families useful in homology modeling and in analyzing protein families in general. It takes as input either the sequence or the structure of a protein and provides alignments with its homologs along with a variety of structural and functional annotations through an interactive interface. The annotations include sequence conservation, similarity scores, ligand-, DNA- and RNA-binding sites, secondary structure, disorder, crystallographic structure resolution and quality scores of models implied by the alignments to the homologs of known structure. MODexplorer can be used to analyze sequence and structural conservation among the structures of similar proteins, to find structures of homologs solved in different conformational state or with different ligands and to transfer functional annotations. Furthermore, if the structure of the query is not known, MODexplorer can be used to select the modeling templates taking all this information into account and to build a comparative model. AVAILABILITY AND IMPLEMENTATION: Freely available on the web at http://modorama.biocomputing.it/modexplorer. Website implemented in HTML and JavaScript with all major browsers supported. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

MODexplorer: an integrated tool for exploring protein sequence, structure and function relationships.

KAUST Repository

Kosinski, Jan

2013-02-08

SUMMARY: MODexplorer is an integrated tool aimed at exploring the sequence, structural and functional diversity in protein families useful in homology modeling and in analyzing protein families in general. It takes as input either the sequence or the structure of a protein and provides alignments with its homologs along with a variety of structural and functional annotations through an interactive interface. The annotations include sequence conservation, similarity scores, ligand-, DNA- and RNA-binding sites, secondary structure, disorder, crystallographic structure resolution and quality scores of models implied by the alignments to the homologs of known structure. MODexplorer can be used to analyze sequence and structural conservation among the structures of similar proteins, to find structures of homologs solved in different conformational state or with different ligands and to transfer functional annotations. Furthermore, if the structure of the query is not known, MODexplorer can be used to select the modeling templates taking all this information into account and to build a comparative model. AVAILABILITY AND IMPLEMENTATION: Freely available on the web at http://modorama.biocomputing.it/modexplorer. Website implemented in HTML and JavaScript with all major browsers supported. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Quantiprot - a Python package for quantitative analysis of protein sequences.

Science.gov (United States)

Konopka, Bogumił M; Marciniak, Marta; Dyrka, Witold

2017-07-17

The field of protein sequence analysis is dominated by tools rooted in substitution matrices and alignments. A complementary approach is provided by methods of quantitative characterization. A major advantage of the approach is that quantitative properties defines a multidimensional solution space, where sequences can be related to each other and differences can be meaningfully interpreted. Quantiprot is a software package in Python, which provides a simple and consistent interface to multiple methods for quantitative characterization of protein sequences. The package can be used to calculate dozens of characteristics directly from sequences or using physico-chemical properties of amino acids. Besides basic measures, Quantiprot performs quantitative analysis of recurrence and determinism in the sequence, calculates distribution of n-grams and computes the Zipf's law coefficient. We propose three main fields of application of the Quantiprot package. First, quantitative characteristics can be used in alignment-free similarity searches, and in clustering of large and/or divergent sequence sets. Second, a feature space defined by quantitative properties can be used in comparative studies of protein families and organisms. Third, the feature space can be used for evaluating generative models, where large number of sequences generated by the model can be compared to actually observed sequences.

Several Families of Sequences with Low Correlation and Large Linear Span

Science.gov (United States)

Zeng, Fanxin; Zhang, Zhenyu

In DS-CDMA systems and DS-UWB radios, low correlation of spreading sequences can greatly help to minimize multiple access interference (MAI) and large linear span of spreading sequences can reduce their predictability. In this letter, new sequence sets with low correlation and large linear span are proposed. Based on the construction Trm1[Trnm(αbt+γiαdt)]r for generating p-ary sequences of period pn-1, where n=2m, d=upm±v, b=u±v, γi∈GF(pn), and p is an arbitrary prime number, several methods to choose the parameter d are provided. The obtained sequences with family size pn are of four-valued, five-valued, six-valued or seven-valued correlation and the maximum nontrivial correlation value is (u+v-1)pm-1. The simulation by a computer shows that the linear span of the new sequences is larger than that of the sequences with Niho-type and Welch-type decimations, and similar to that of [10].

Templated sequence insertion polymorphisms in the human genome

Science.gov (United States)

Onozawa, Masahiro; Aplan, Peter

2016-11-01

Templated Sequence Insertion Polymorphism (TSIP) is a recently described form of polymorphism recognized in the human genome, in which a sequence that is templated from a distant genomic region is inserted into the genome, seemingly at random. TSIPs can be grouped into two classes based on nucleotide sequence features at the insertion junctions; Class 1 TSIPs show features of insertions that are mediated via the LINE-1 ORF2 protein, including 1) target-site duplication (TSD), 2) polyadenylation 10-30 nucleotides downstream of a “cryptic” polyadenylation signal, and 3) preference for insertion at a 5’-TTTT/A-3’ sequence. In contrast, class 2 TSIPs show features consistent with repair of a DNA double-strand break via insertion of a DNA “patch” that is derived from a distant genomic region. Survey of a large number of normal human volunteers demonstrates that most individuals have 25-30 TSIPs, and that these TSIPs track with specific geographic regions. Similar to other forms of human polymorphism, we suspect that these TSIPs may be important for the generation of human diversity and genetic diseases.

Amino acid similarity accounts for T cell cross-reactivity and for "holes" in the T cell repertoire

DEFF Research Database (Denmark)

Pletscher-Frankild, Sune; de Boer, Rob J.; Lund, Ole

2008-01-01

Background: Cytotoxic T cell (CTL) cross-reactivity is believed to play a pivotal role in generating immune responses but the extent and mechanisms of CTL cross-reactivity remain largely unknown. Several studies suggest that CTL clones can recognize highly diverse peptides, some sharing no obvious...... sequence identity. The emerging realization in the field is that T cell receptors (TcR) recognize multiple distinct ligands. Principal Findings: First, we analyzed peptide scans of the HIV epitope SLFNTVATL (SFL9) and found that TCR specificity is position dependent and that biochemically similar amino...... to demonstrate that seemingly distinct T cell epitopes, i.e., ones with low sequence identity, are in fact more biochemically similar than expected. Additionally, an analysis of HIV immunogenicity data with our model showed that CTLs have the tendency to respond mostly to peptides that do not resemble self...

CpGAVAS, an integrated web server for the annotation, visualization, analysis, and GenBank submission of completely sequenced chloroplast genome sequences

Science.gov (United States)

2012-01-01

Background The complete sequences of chloroplast genomes provide wealthy information regarding the evolutionary history of species. With the advance of next-generation sequencing technology, the number of completely sequenced chloroplast genomes is expected to increase exponentially, powerful computational tools annotating the genome sequences are in urgent need. Results We have developed a web server CPGAVAS. The server accepts a complete chloroplast genome sequence as input. First, it predicts protein-coding and rRNA genes based on the identification and mapping of the most similar, full-length protein, cDNA and rRNA sequences by integrating results from Blastx, Blastn, protein2genome and est2genome programs. Second, tRNA genes and inverted repeats (IR) are identified using tRNAscan, ARAGORN and vmatch respectively. Third, it calculates the summary statistics for the annotated genome. Fourth, it generates a circular map ready for publication. Fifth, it can create a Sequin file for GenBank submission. Last, it allows the extractions of protein and mRNA sequences for given list of genes and species. The annotation results in GFF3 format can be edited using any compatible annotation editing tools. The edited annotations can then be uploaded to CPGAVAS for update and re-analyses repeatedly. Using known chloroplast genome sequences as test set, we show that CPGAVAS performs comparably to another application DOGMA, while having several superior functionalities. Conclusions CPGAVAS allows the semi-automatic and complete annotation of a chloroplast genome sequence, and the visualization, editing and analysis of the annotation results. It will become an indispensible tool for researchers studying chloroplast genomes. The software is freely accessible from http://www.herbalgenomics.org/cpgavas. PMID:23256920

CpGAVAS, an integrated web server for the annotation, visualization, analysis, and GenBank submission of completely sequenced chloroplast genome sequences

Directory of Open Access Journals (Sweden)

Liu Chang

2012-12-01

Full Text Available Abstract Background The complete sequences of chloroplast genomes provide wealthy information regarding the evolutionary history of species. With the advance of next-generation sequencing technology, the number of completely sequenced chloroplast genomes is expected to increase exponentially, powerful computational tools annotating the genome sequences are in urgent need. Results We have developed a web server CPGAVAS. The server accepts a complete chloroplast genome sequence as input. First, it predicts protein-coding and rRNA genes based on the identification and mapping of the most similar, full-length protein, cDNA and rRNA sequences by integrating results from Blastx, Blastn, protein2genome and est2genome programs. Second, tRNA genes and inverted repeats (IR are identified using tRNAscan, ARAGORN and vmatch respectively. Third, it calculates the summary statistics for the annotated genome. Fourth, it generates a circular map ready for publication. Fifth, it can create a Sequin file for GenBank submission. Last, it allows the extractions of protein and mRNA sequences for given list of genes and species. The annotation results in GFF3 format can be edited using any compatible annotation editing tools. The edited annotations can then be uploaded to CPGAVAS for update and re-analyses repeatedly. Using known chloroplast genome sequences as test set, we show that CPGAVAS performs comparably to another application DOGMA, while having several superior functionalities. Conclusions CPGAVAS allows the semi-automatic and complete annotation of a chloroplast genome sequence, and the visualization, editing and analysis of the annotation results. It will become an indispensible tool for researchers studying chloroplast genomes. The software is freely accessible from http://www.herbalgenomics.org/cpgavas.

Sequence and expression pattern of the germ line marker vasa in honey bees and stingless bees

Science.gov (United States)

2009-01-01

Queens and workers of social insects differ in the rates of egg laying. Using genomic information we determined the sequence of vasa, a highly conserved gene specific to the germ line of metazoans, for the honey bee and four stingless bees. The vasa sequence of social bees differed from that of other insects in two motifs. By RT-PCR we confirmed the germ line specificity of Amvasa expression in honey bees. In situ hybridization on ovarioles showed that Amvasa is expressed throughout the germarium, except for the transition zone beneath the terminal filament. A diffuse vasa signal was also seen in terminal filaments suggesting the presence of germ line cells. Oocytes showed elevated levels of Amvasa transcripts in the lower germarium and after follicles became segregated. In previtellogenic follicles, Amvasa transcription was detected in the trophocytes, which appear to supply its mRNA to the growing oocyte. A similar picture was obtained for ovarioles of the stingless bee Melipona quadrifasciata, except that Amvasa expression was higher in the oocytes of previtellogenic follicles. The social bees differ in this respect from Drosophila, the model system for insect oogenesis, suggesting that changes in the sequence and expression pattern of vasa may have occurred during social evolution. PMID:21637523

Sequence and expression pattern of the germ line marker vasa in honey bees and stingless bees

Directory of Open Access Journals (Sweden)

Érica Donato Tanaka

2009-01-01

Full Text Available Queens and workers of social insects differ in the rates of egg laying. Using genomic information we determined the sequence of vasa, a highly conserved gene specific to the germ line of metazoans, for the honey bee and four stingless bees. The vasa sequence of social bees differed from that of other insects in two motifs. By RT-PCR we confirmed the germ line specificity of Amvasa expression in honey bees. In situ hybridization on ovarioles showed that Amvasa is expressed throughout the germarium, except for the transition zone beneath the terminal filament. A diffuse vasa signal was also seen in terminal filaments suggesting the presence of germ line cells. Oocytes showed elevated levels of Amvasa transcripts in the lower germarium and after follicles became segregated. In previtellogenic follicles, Amvasa transcription was detected in the trophocytes, which appear to supply its mRNA to the growing oocyte. A similar picture was obtained for ovarioles of the stingless bee Melipona quadrifasciata, except that Amvasa expression was higher in the oocytes of previtellogenic follicles. The social bees differ in this respect from Drosophila, the model system for insect oogenesis, suggesting that changes in the sequence and expression pattern of vasa may have occurred during social evolution.