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  • 1
    Keywords: Bioinformatics -- Congresses. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (384 pages)
    Edition: 1st ed.
    ISBN: 9783642152948
    Series Statement: Lecture Notes in Computer Science Series ; v.6293
    DDC: 572.80285
    Language: English
    Note: Title -- Preface -- Organization -- Table of Contents -- Biomolecular Structure: RNA, Protein and Molecular Comparison -- A Worst-Case and Practical Speedup for theRNA Co-folding Problem Using theFour-{\itRussians} Idea -- Introduction -- Sankoff Algorithm for Two Sequences -- Recurrences for finding the Optimal Co-fold. -- Cofold Algorithm -- Conceptually Speeding Up the Branch_function -- Implementing the Branch Function with Table R^2 -- R^2 Table Integration into Branching -- Precomputing the R^2 Table -- Fast Cofold Algorithm -- Asymptotic Time Analysis -- Memory -- Empirical Results -- Conclusion and Future Work -- References -- Sparse Estimation for Structural Variability -- Introduction -- Related Work -- Methods -- Ensemble Construction -- Analysis of Variability Using Lasso -- Electron Density Map -- Results -- Synthetic Data -- Real Data -- Conclusions -- References -- Data Structures for Accelerating Tanimoto Queries on Real Valued Vectors -- Introduction -- Data Structures -- Experimental Setup -- Results -- Conclusion -- References -- Sparsification of RNA Structure Prediction Including Pseudoknots -- Introduction -- Sparsification of the Reeder and Giegerich algorithm -- Sparsification of the Rivas and Eddy Algorithm -- Experimental Results -- Conclusion -- References -- Prediction of RNA Secondary Structure Including Kissing Hairpin Motifs -- Introduction -- Biological Relevance of Pseudoknots in RNA Structure -- RNA Folding of Nested Structures -- Folding Pseudoknots -- Typology of Structures -- Three Strategies for Kissing Hairpin Prediction -- The Combined Power of Canonization Rules and Non-ambiguous Dynamic Programming -- Decomposition Alternatives of the Kissing Hairpin Motif -- Strategy A - An O(n^4) Time, O(n^2) Space Algorithm -- Strategy B - An O(n^4) Time, O(n^2) Space Algorithm. , Strategy C - An O(n^5) Time, O(n^2) Space Algorithm -- Algorithms -- Algorithmic Subtleties -- Pseudoknot-Recurrence of {\it pknots}RG - csrPK -- Recurrences of Strategy A - csrKH_A -- Recurrences of Strategy B - csrKH_B -- Recurrences of Strategy C - csrKH_C -- Implementation via Algebraic Dynamic Programming -- Evaluation of Strategies A, B, and C -- Conclusion -- References -- Reducing the Worst Case Running Times of a Family of RNA and CFG Problems, Using Valiant's Approach -- Introduction -- Preliminaries -- Interval and Matrix Notations -- String Notations -- The Inside Vector Multiplication Template -- Example: RNA Base-Pairing Maximization -- Inside VMT Definition -- Inside VMT Algorithm -- Additional Vector Multiplication Templates -- Outside VMT -- Multiple String VMT -- Concluding Discussion -- References -- Comparative Genomics -- Reconstruction of Ancestral Genome Subject to Whole Genome Duplication, Speciation, Rearrangement and Loss -- Introduction -- Preliminaries -- Problem Definition -- Method -- Computing Adjacency Scores -- Assembling an Pre-duplication Ancestral Genome -- Results -- Simulated Data Sets -- Comparison with the Gordon et al. Ancestor -- Conclusion -- References -- Genomic Distance with DCJ and Indels -- Introduction -- DCJ, Adjacency Graph and Indels -- Accumulating Runs with Optimal DCJ Operations -- Merging Runs in One Component -- Recombinations and the DCJ-indel Distance -- Experiments and Discussion -- References -- Listing All Sorting Reversals in Quadratic Time -- Introduction -- Background -- All Sorting Reversals -- Outline -- Ominous Substrings -- Permutation with a Single Component -- Permutations with Multiple Components -- Detecting Ominous Substrings -- The Algorithm -- Conclusions -- References -- Haplotype and Genotype Analysis -- Discovering Kinship through Small Subsets -- Introduction. , Related Work -- Preliminaries and Notation -- Forbidden Sets -- Forbidden Sets Are Triplets -- Forbidden Triplets as a Means of Finding a Partition -- Experimental Results -- Accuracy Measure -- Simulation Results -- Real Data -- Probabilistic Arguments -- A Probabilistic Model -- A Simplified Algorithm -- A Bound with Two Families -- Extending to Multiple Families -- Extending to More Robust Models -- Future Work -- References -- Fixed-Parameter Algorithm for Haplotype Inferences on General Pedigrees with Small Number of Sites -- Introduction -- Preliminaries -- Setting Up Graphs -- Pedigree Graph -- Parity-Constraint Sets -- Signed Graph -- Fixed-Parameter Algorithm -- Transforming to Bipartization by Edge Removal Problem -- FPT Algorithm for Bipartization by Edge Removal -- Conclusion -- References -- Haplotypes versus Genotypes on Pedigrees -- Introduction to Pedigree Analysis -- Pedigree Problem Formulations -- Hardness Results -- Algorithms and Accuracy of Estimates -- General Haplotype and Genotype HMMs -- Haplotype Likelihoods in Linear Time -- Results -- Discussion -- References -- Haplotype Inference on Pedigrees with Recombinations and Mutations -- Motivations -- The Computational Problem -- A Heuristic Algorithm for MCHC -- A System of Linear Equations for MCHC -- A Linear System for ZRHC -- A Linear System for MCHC -- Reducing MCHC to NCP -- The Heuristic Algorithm -- Experimental Results -- Evaluation on Random Instances -- Comparison with State-of-the-Art Methods -- Conclusion -- References -- High-throughput Data Analysis: Next Generation Sequencing and Flow Cytometry -- Identifying Rare Cell Populations in Comparative Flow Cytometry -- Introduction -- Problem Formulation -- Description of Data -- Model of the Data -- Basic Definitions -- Objectives -- Methods -- Clustering -- Pairwise Comparison: Generalized Edge Cover. , Comparing Multiple Clusters -- Results -- Clustering Results -- Pairwise Comparison Results -- Coherent Groups -- Distinctive and Common Outliers -- Probabilistic Model for Groups -- Effect of APL on Bone Marrow Cells -- References -- Fast Mapping and Precise Alignment of AB SOLiD Color Reads to Reference DNA -- Introduction -- Methods -- Sequences and Numerical Encoding -- Color Read Indexing -- Greedy Alignment between Color Read and DNA Sequence -- Statistical Alignment for Color Reads -- Likelihood and Posterior Probabilities -- Experiments -- Conclusion -- References -- Design of an Efficient Out-of-Core Read Alignment Algorithm -- Introduction -- Algorithm -- Definitions -- The Basic Sort-and-Join Method -- Sort-and-Join Method for Mapping with Errors -- Implementation of Syzygy -- Encoding, Key Generation and Other Bitwise Tricks -- Main List Data Structures -- Managing "Blowups" in the Join List -- Overlapped I/O -- Sorting -- Results and Discussion -- Conclusion -- References -- Estimation of Alternative Splicing isoform Frequencies from RNA-Seq Data -- Introduction -- Related Work -- Our Contributions -- Methods -- Read Mapping -- Finding Read-Isoform Compatibilities -- The IsoEM Algorithm -- Experimental Results -- Simulation Setup -- Comparison between Methods -- Influence of Sequencing Parameters -- Conclusions and Ongoing Work -- References -- Networks -- Improved Orientations of Physical Networks -- Introduction -- Orienting Undirected Graphs -- The Classification Process -- An Orientation Algorithm for a Single Decomposition -- Orienting Mixed Graphs -- The Approximation Algorithm -- Conclusions -- References -- Enumerating Chemical Organisations in Consistent Metabolic Networks: Complexity and Algorithms -- Introduction -- Preliminaries -- Chemical Organisations in Consistent Networks -- Enumerating Chemical Organisations. , Hitting Set Approach to Enumerate Organisations -- Conclusion -- References -- Efficient Subgraph Frequency Estimation with G-Tries -- Introduction -- Preliminaries -- Graph Terminology -- Network Motifs and Frequency Count -- Related Work -- Sampling Algorithm -- G-Tries Data Structure -- Exact Subgraph Frequency -- Uniform Sampling -- Network Motif Discovery -- Results -- Conclusion -- References -- Phylogenetics -- Accuracy Guarantees for Phylogeny Reconstruction Algorithms Based on Balanced Minimum Evolution -- Introduction -- Basics, Definitions and Notation -- Results -- Proofs -- GreedyBME -- Local Topology Search -- Conclusion -- References -- The Complexity of Inferring a Minimally Resolved Phylogenetic Supertree -- Introduction -- Our Results and Organization of the Paper -- Preliminaries -- Basic Definitions -- The Algorithm of Aho et al. ASSU81 (BUILD) -- Definition of MinRS -- Related Work -- Polynomial-Time Inapproximability of MinRS -- Exact Algorithms for MinRS -- A Brute-Force Algorithm -- An Exponential-Time Algorithm for a Restricted Case of MinRS -- Concluding Remarks -- References -- Reducing Multi-state to Binary Perfect Phylogeny with Applications to Missing, Removable, Inserted, and Deleted Data -- Introduction and Background -- Reducing k-States to Binary -- Reducing k-State Perfect Phylogeny to Binary Perfect Phylogeny with Missing Data -- Extension to k-State Perfect Phylogeny with Missing Data -- Solving the MD Problem for Arbitrary k -- Solving the CR and MDCR Problems for Arbitrary k -- Insertions and Deletions as Phylogenetic Characters -- Insertions and Deletions as Phylogenetic Characters -- References -- An Experimental Study of Quartets MaxCut and Other Supertree Methods -- Introduction -- Basics -- Performance Study -- Results -- Exploring QMC under Different Source Tree Encodings. , Comparing QMC(Exp+TSQ) to Other Supertree Methods.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 51 (2000), S. 194-204 
    ISSN: 1432-1432
    Keywords: Key words: RNase MRP — RNase P — RNA secondary structure — RNA-world — Catalytic RNA — Evolutionary trees — Covarion hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Secondary structure is evaluated for determining evolutionary relationships between catalytic RNA molecules that are so distantly related they are scarcely alignable. The ribonucleoproteins RNase P (P) and RNase MRP (MRP) have been suggested to be evolutionarily related because of similarities in both function and secondary structure. However, their RNA sequences cannot be aligned with any confidence, and this leads to uncertainty in any trees inferred from sequences. We report several approaches to using secondary structures for inferring evolutionary trees and emphasize quantitative tests to demonstrate that evolutionary information can be recovered. For P and MRP, three hypotheses for the relatedness are considered. The first is that MRP is derived from P in early eukaryotes. The next is that MRP is derived from P from an early endosymbiont. The third is that both P and MRP evolved in the RNA-world (and the need for MRP has since been lost in prokaryotes). Quantitative comparisons of the pRNA and mrpRNA secondary structures have found that the possibility of an organellar origin of MRP is unlikely. In addition, comparison of secondary structures support the identity of an RNase P–like sequence in the maize chloroplast genome. Overall, it is concluded that RNA secondary structure is useful for evaluating evolutionary relatedness, even with sequences that cannot be aligned with confidence.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1432
    Keywords: Key words: Circular dichroism — Origin of life — RNA folding — RNA secondary structure — RNA world
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Opinion is strongly divided on whether life arose on earth under hot or cold conditions, the hot-start and cold-start scenarios, respectively. The origin of life close to deep thermal vents appears as the majority opinion among biologists, but there is considerable biochemical evidence that high temperatures are incompatible with an RNA world. To be functional, RNA has to fold into a three-dimensional structure. We report both theoretical and experimental results on RNA folding and show that (as expected) hot conditions strongly reduce RNA folding. The theoretical results come from energy-minimization calculations of the average extent of folding of RNA, mainly from 0–90°C, for both random sequences and tRNA sequences. The experimental results are from circular-dichroism measurements of tRNA over a similar range of temperatures. The quantitative agreement between calculations and experiment is remarkable, even to the shape of the curves indicating the cooperative nature of RNA folding and unfolding. These results provide additional evidence for a lower temperature stage being necessary in the origin of life.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2020-07-30
    Description: The advent of genomic-, transcriptomic- and proteomic-based approaches has revolutionized our ability to describe marine microbial communities, including biogeography, metabolic potential and diversity, mechanisms of adaptation, and phylogeny and evolutionary history. New interdisciplinary approaches are needed to move from this descriptive level to improved quantitative, process-level understanding of the roles of marine microbes in biogeochemical cycles and of the impact of environmental change on the marine microbial ecosystem. Linking studies at levels from the genome to the organism, to ecological strategies and organism and ecosystem response, requires new modelling approaches. Key to this will be a fundamental shift in modelling scale that represents micro-organisms from the level of their macromolecular components. This will enable contact with omics data sets and allow acclimation and adaptive response at the phenotype level (i.e. traits) to be simulated as a combination of fitness maximization and evolutionary constraints. This way forward will build on ecological approaches that identify key organism traits and systems biology approaches that integrate traditional physiological measurements with new insights from omics. It will rely on developing an improved understanding of ecophysiology to understand quantitatively environmental controls on microbial growth strategies. It will also incorporate results from experimental evolution studies in the representation of adaptation. The resulting ecosystem-level models can then evaluate our level of understanding of controls on ecosystem structure and function, highlight major gaps in understanding and help prioritize areas for future research programs. Ultimately, this grand synthesis should improve predictive capability of the ecosystem response to multiple environmental drivers.
    Type: Article , PeerReviewed
    Format: text
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  • 5
    Publication Date: 2024-02-07
    Description: Zinc is an essential trace metal for oceanic primary producers with the highest concentrations in polar oceans. However, its role in the biological functioning and adaptive evolution of polar phytoplankton remains enigmatic. Here, we have applied a combination of evolutionary genomics, quantitative proteomics, co-expression analyses and cellular physiology to suggest that model polar phytoplankton species have a higher demand for zinc because of elevated cellular levels of zinc-binding proteins. We propose that adaptive expansion of regulatory zinc-finger protein families, co-expanded and co-expressed zinc-binding proteins families involved in photosynthesis and growth in these microalgal species and their natural communities were identified to be responsible for the higher zinc demand. The expression of their encoding genes in eukaryotic phytoplankton metatranscriptomes from pole-to-pole was identified to correlate not only with dissolved zinc concentrations in the upper ocean but also with temperature, suggesting that environmental conditions of polar oceans are responsible for an increased demand of zinc. These results suggest that zinc plays an important role in supporting photosynthetic growth in eukaryotic polar phytoplankton and that this has been critical for algal colonization of low-temperature polar oceans.
    Type: Article , PeerReviewed
    Format: text
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  • 6
    Publication Date: 2019-03-08
    Description: The Southern Ocean houses a diverse and productive community of organisms. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus based on a comparison with temperate diatoms. We find that approximately 24.7 per cent of the diploid F. cylindrus genome consists of genetic loci with alleles that are highly divergent from those of temperate diatoms (15.1 megabases of the total genome size of 61.1 megabases). These divergent alleles were differentially expressed across environmental conditions, including darkness, low iron, freezing, elevated temperature and increased CO2. Alleles with the largest ratio of non-synonymous to synonymous nucleotide substitutions also show the most pronounced condition-dependent expression, suggesting a correlation between diversifying selection and allelic differentiation. Divergent alleles may be involved in adaptation to environmental fluctuations in the Southern Ocean.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 7
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 8
    Publication Date: 2022-08-15
    Description: Marine phytoplankton are responsible for ~50% of the CO2 that is fixed annually, worldwide, and contribute massively to other biogeochemical cycles in the oceans1. Their contribution depends significantly on the interplay between dynamic environmental conditions and metabolic responses that underpin resource allocation and hence biogeochemical cycling in the oceans. However, these complex environment-biome interactions have not been studied on a larger scale. Here we use a novel set of integrative approaches that combine metatranscriptomes, biochemical data, cellular physiology and emergent phytoplankton growth strategies in a global ecosystems model, to show that temperature significantly affects eukaryotic phytoplankton metabolism with consequences for biogeochemical cycling under global warming. In particular, the rate of protein synthesis strongly increases under high temperatures even though the numbers of ribosomes and their associated rRNAs decreases. Thus, at higher temperatures, eukaryotic phytoplankton seem to require a lower density of ribosomes to produce the required amounts of cellular protein. The reduction of P-rich ribosomes2 in warmer oceans will tend to produce higher organismal N:P ratios, in turn increasing demand for N with consequences for the marine carbon cycle due to shifts toward N-limitation. Our integrative approach suggests that temperature plays a previously unrecognized, critical role in resource allocation and marine phytoplankton stoichiometry with implications for the biogeochemical cycles that they drive.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 9
    Publication Date: 2022-08-15
    Description: Eukaryotic phytoplankton are responsible for at least 20% of annual global carbonfixation.Their diversity and activity are shaped by interactions with prokaryotes as part of complexmicrobiomes. Although differences in their local species diversity have been estimated, westill have a limited understanding of environmental conditions responsible for compositionaldifferences between local species communities on a large scale from pole to pole. Here, weshow, based on pole-to-pole phytoplankton metatranscriptomes and microbial rDNAsequencing, that environmental differences between polar and non-polar upper oceans moststrongly impact the large-scale spatial pattern of biodiversity and gene activity in algalmicrobiomes. The geographic differentiation of co-occurring microbes in algal microbiomescan be well explained by the latitudinal temperature gradient and associated break points intheir beta diversity, with an average breakpoint at 14 °C ± 4.3, separating cold and warmupper oceans. As global warming impacts upper ocean temperatures, we project that breakpoints of beta diversity move markedly pole-wards. Hence, abrupt regime shifts in algalmicrobiomes could be caused by anthropogenic climate change.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
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  • 10
    Publication Date: 2023-06-21
    Description: Multiomics approaches need to be applied in the central Arctic Ocean to benchmark biodiversity change and to identify novel species and their genes. As part of MOSAiC, EcoOmics will therefore be essential for conservation and sustainable bioprospecting in one of the least explored ecosystems on Earth.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
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