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Find video protocols related to scientific articles indexed in Pubmed.
Phylogenomics resolves the timing and pattern of insect evolution.
Bernhard Misof, Shanlin Liu, Karen Meusemann, Ralph S Peters, Alexander Donath, Christoph Mayer, Paul B Frandsen, Jessica Ware, Tomáš Flouri, Rolf G Beutel, Oliver Niehuis, Malte Petersen, Fernando Izquierdo-Carrasco, Torsten Wappler, Jes Rust, Andre J Aberer, Ulrike Aspöck, Horst Aspöck, Daniela Bartel, Alexander Blanke, Simon Berger, Alexander Böhm, Thomas R Buckley, Brett Calcott, Junqing Chen, Frank Friedrich, Makiko Fukui, Mari Fujita, Carola Greve, Peter Grobe, Shengchang Gu, Ying Huang, Lars S Jermiin, Akito Y Kawahara, Lars Krogmann, Martin Kubiak, Robert Lanfear, Harald Letsch, Yiyuan Li, Zhenyu Li, Jiguang Li, Haorong Lu, Ryuichiro Machida, Yuta Mashimo, Pashalia Kapli, Duane D McKenna, Guanliang Meng, Yasutaka Nakagaki, José Luis Navarrete-Heredia, Michael Ott, Yanxiang Ou, Günther Pass, Lars Podsiadlowski, Hans Pohl, Björn M von Reumont, Kai Schütte, Kaoru Sekiya, Shota Shimizu, Adam Slipinski, Alexandros Stamatakis, Wenhui Song, Xu Su, Nikolaus U Szucsich, Meihua Tan, Xuemei Tan, Min Tang, Jingbo Tang, Gerald Timelthaler, Shigekazu Tomizuka, Michelle Trautwein, Xiaoli Tong, Toshiki Uchifune, Manfred G Walzl, Brian M Wiegmann, Jeanne Wilbrandt, Benjamin Wipfler, Thomas K F Wong, Qiong Wu, Gengxiong Wu, Yinlong Xie, Shenzhou Yang, Qing Yang, David K Yeates, Kazunori Yoshizawa, Qing Zhang, Rui Zhang, Wenwei Zhang, Yunhui Zhang, Jing Zhao, Chengran Zhou, Lili Zhou, Tanja Ziesmann, Shijie Zou, Yingrui Li, Xun Xu, Yong Zhang, Huanming Yang, Jian Wang, Jun Wang, Karl M Kjer, Xin Zhou.
Science
PUBLISHED: 11-06-2014
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Insects are the most speciose group of animals, but the phylogenetic relationships of many major lineages remain unresolved. We inferred the phylogeny of insects from 1478 protein-coding genes. Phylogenomic analyses of nucleotide and amino acid sequences, with site-specific nucleotide or domain-specific amino acid substitution models, produced statistically robust and congruent results resolving previously controversial phylogenetic relations hips. We dated the origin of insects to the Early Ordovician [~479 million years ago (Ma)], of insect flight to the Early Devonian (~406 Ma), of major extant lineages to the Mississippian (~345 Ma), and the major diversification of holometabolous insects to the Early Cretaceous. Our phylogenomic study provides a comprehensive reliable scaffold for future comparative analyses of evolutionary innovations among insects.
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A Polychaete's powerful punch: venom gland transcriptomics of Glycera reveals a complex cocktail of toxin homologs.
Genome Biol Evol
PUBLISHED: 09-05-2014
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Glycerids are marine annelids commonly known as bloodworms. Bloodworms have an eversible proboscis adorned with jaws connected to venom glands. Bloodworms prey on invertebrates, and it is known that the venom glands produce compounds that can induce toxic effects in animals. Yet, none of these putative toxins has been characterized on a molecular basis. Here we present the transcriptomic profiles of the venom glands of three species of bloodworm, Glycera dibranchiata, Glycera fallax and Glycera tridactyla, as well as the body tissue of G. tridactyla. The venom glands express a complex mixture of transcripts coding for putative toxin precursors. These transcripts represent 20 known toxin classes that have been convergently recruited into animal venoms, as well as transcripts potentially coding for Glycera-specific toxins. The toxins represent five functional categories: Pore-forming and membrane-disrupting toxins, neurotoxins, protease inhibitors, other enzymes, and CAP domain toxins. Many of the transcripts coding for putative Glycera toxins belong to classes that have been widely recruited into venoms, but some are homologs of toxins previously only known from the venoms of scorpaeniform fish and monotremes (stonustoxin-like toxin), turrid gastropods (turripeptide-like peptides), and sea anemones (gigantoxin I-like neurotoxin). This complex mixture of toxin homologs suggests that bloodworms employ venom while predating on macroscopic prey, casting doubt on the previously widespread opinion that G. dibranchiata is a detritivore. Our results further show that researchers should be aware that different assembly methods, as well as different methods of homology prediction, can influence the transcriptomic profiling of venom glands.
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The First Venomous Crustacean Revealed by Transcriptomics and Functional Morphology: Remipede Venom Glands Express a Unique Toxin Cocktail Dominated by Enzymes and a Neurotoxin.
Mol. Biol. Evol.
PUBLISHED: 10-16-2013
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Animal venoms have evolved many times. Venomous species are especially common in three of the four main groups of arthropods (Chelicerata, Myriapoda, and Hexapoda), which together represent tens of thousands of species of venomous spiders, scorpions, centipedes, and hymenopterans. Surprisingly, despite their great diversity of body plans, there is no unambiguous evidence that any crustacean is venomous. We provide the first conclusive evidence that the aquatic, blind, and cave-dwelling remipede crustaceans are venomous and that venoms evolved in all four major arthropod groups. We produced a three-dimensional reconstruction of the venom delivery apparatus of the remipede Speleonectes tulumensis, showing that remipedes can inject venom in a controlled manner. A transcriptomic profile of its venom glands shows that they express a unique cocktail of transcripts coding for known venom toxins, including a diversity of enzymes and a probable paralytic neurotoxin very similar to one described from spider venom. We screened a transcriptomic library obtained from whole animals and identified a nontoxin paralog of the remipede neurotoxin that is not expressed in the venom glands. This allowed us to reconstruct its probable evolutionary origin and underlines the importance of incorporating data derived from nonvenom gland tissue to elucidate the evolution of candidate venom proteins. This first glimpse into the venom of a crustacean and primitively aquatic arthropod reveals conspicuous differences from the venoms of other predatory arthropods such as centipedes, scorpions, and spiders and contributes valuable information for ultimately disentangling the many factors shaping the biology and evolution of venoms and venomous species.
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De novo Ixodes ricinus salivary gland transcriptome analysis using two next-generation sequencing methodologies.
FASEB J.
PUBLISHED: 08-20-2013
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Tick salivary gland (SG) proteins possess powerful pharmacologic properties that facilitate tick feeding and pathogen transmission. For the first time, SG transcriptomes of Ixodes ricinus, an important disease vector for humans and animals, were analyzed using next-generation sequencing. SGs were collected from different tick life stages fed on various animal species, including cofeeding of nymphs and adults on the same host. Four cDNA samples were sequenced, discriminating tick SG transcriptomes of early- and late-feeding nymphs or adults. In total, 441,381,454 pyrosequencing reads and 67,703,183 Illumina reads were assembled into 272,220 contigs, of which 34,560 extensively annotated coding sequences are disclosed; 8686 coding sequences were submitted to GenBank. Overall, 13% of contigs were classified as secreted proteins that showed significant differences in the transcript representation among the 4 SG samples, including high numbers of sample-specific transcripts. Detailed phylogenetic reconstructions of two relatively abundant SG-secreted protein families demonstrated how this study improves our understanding of the molecular evolution of hematophagy in arthropods. Our data significantly increase the available genomic information for I. ricinus and form a solid basis for future tick genome/transcriptome assemblies and the functional analysis of effectors that mediate the feeding physiology and parasite-vector interaction of I. ricinus.-Schwarz, A., von Reumont, B.M., Erhart, J., Chagas, A.C., Ribeiro, J.M.C., Kotsyfakis, M. De novo Ixodes ricinus salivary gland transcriptome analysis using two next-generation sequencing methodologies.
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Selecting informative subsets of sparse supermatrices increases the chance to find correct trees.
BMC Bioinformatics
PUBLISHED: 05-29-2013
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Character matrices with extensive missing data are frequently used in phylogenomics with potentially detrimental effects on the accuracy and robustness of tree inference. Therefore, many investigators select taxa and genes with high data coverage. Drawbacks of these selections are their exclusive reliance on data coverage without consideration of actual signal in the data which might, thus, not deliver optimal data matrices in terms of potential phylogenetic signal. In order to circumvent this problem, we have developed a heuristics implemented in a software called mare which (1) assesses information content of genes in supermatrices using a measure of potential signal combined with data coverage and (2) reduces supermatrices with a simple hill climbing procedure to submatrices with high total information content. We conducted simulation studies using matrices of 50 taxa x 50 genes with heterogeneous phylogenetic signal among genes and data coverage between 10 - 30 %.
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A comprehensive analysis of bilaterian mitochondrial genomes and phylogeny.
Mol. Phylogenet. Evol.
PUBLISHED: 04-27-2013
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About 2800 mitochondrial genomes of Metazoa are present in NCBI RefSeq today, two thirds belonging to vertebrates. Metazoan phylogeny was recently challenged by large scale EST approaches (phylogenomics), stabilizing classical nodes while simultaneously supporting new sister group hypotheses. The use of mitochondrial data in deep phylogeny analyses was often criticized because of high substitution rates on nucleotides, large differences in amino acid substitution rate between taxa, and biases in nucleotide frequencies. Nevertheless, mitochondrial genome data might still be promising as it allows for a larger taxon sampling, while presenting a smaller amount of sequence information. We present the most comprehensive analysis of bilaterian relationships based on mitochondrial genome data. The analyzed data set comprises more than 650 mitochondrial genomes that have been chosen to represent a profound sample of the phylogenetic as well as sequence diversity. The results are based on high quality amino acid alignments obtained from a complete reannotation of the mitogenomic sequences from NCBI RefSeq database. However, the results failed to give support for many otherwise undisputed high-ranking taxa, like Mollusca, Hexapoda, Arthropoda, and suffer from extreme long branches of Nematoda, Platyhelminthes, and some other taxa. In order to identify the sources of misleading phylogenetic signals, we discuss several problems associated with mitochondrial genome data sets, e.g. the nucleotide and amino acid landscapes and a strong correlation of gene rearrangements with long branches.
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Serotonin-immunoreactive neurons in the ventral nerve cord of Remipedia (Crustacea): support for a sister group relationship of Remipedia and Hexapoda?
BMC Evol. Biol.
PUBLISHED: 02-06-2013
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Remipedia were initially seen as a primitive taxon within Pancrustacea based on characters considered ancestral, such as the homonomously segmented trunk. Meanwhile, several morphological and molecular studies proposed a more derived position of Remipedia within Pancrustacea, including a sister group relationship to Hexapoda. Because of these conflicting hypotheses, fresh data are crucial to contribute new insights into euarthropod phylogeny. The architecture of individually identifiable serotonin-immunoreactive neurons has successfully been used for phylogenetic considerations in Euarthropoda. Here, we identified neurons in three species of Remipedia with an antiserum against serotonin and compared our findings to reconstructed ground patterns in other euarthropod taxa. Additionally, we traced neurite connectivity and neuropil outlines using antisera against acetylated ?-tubulin and synapsin.
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Dating the arthropod tree based on large-scale transcriptome data.
Mol. Phylogenet. Evol.
PUBLISHED: 03-18-2011
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Molecular sequences do not only allow the reconstruction of phylogenetic relationships among species, but also provide information on the approximate divergence times. Whereas the fossil record dates the origin of most multicellular animal phyla during the Cambrian explosion less than 540 million years ago(mya), molecular clock calculations usually suggest much older dates. Here we used a large multiple sequence alignment derived from Expressed Sequence Tags and genomes comprising 129genes (37,476 amino acid positions) and 117 taxa, including 101 arthropods. We obtained consistent divergence time estimates applying relaxed Bayesian clock models with different priors and multiple calibration points. While the influence of substitution rates, missing data, and model priors were negligible, the clock model had significant effect. A log-normal autocorrelated model was selected on basis of cross-validation. We calculated that arthropods emerged ~600 mya. Onychophorans (velvet worms) and euarthropods split ~590 mya, Pancrustacea and Myriochelata ~560 mya, Myriapoda and Chelicerata ~555 mya, and Crustacea and Hexapoda ~510 mya. Endopterygote insects appeared ~390 mya. These dates are considerably younger than most previous molecular clock estimates and in better agreement with the fossil record. Nevertheless, a Precambrian origin of arthropods and other metazoan phyla is still supported. Our results also demonstrate the applicability of large datasets of random nuclear sequences for approximating the timing of multicellular animal evolution.
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A phylogenomic approach to resolve the arthropod tree of life.
Mol. Biol. Evol.
PUBLISHED: 06-09-2010
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Arthropods were the first animals to conquer land and air. They encompass more than three quarters of all described living species. This extraordinary evolutionary success is based on an astoundingly wide array of highly adaptive body organizations. A lack of robustly resolved phylogenetic relationships, however, currently impedes the reliable reconstruction of the underlying evolutionary processes. Here, we show that phylogenomic data can substantially advance our understanding of arthropod evolution and resolve several conflicts among existing hypotheses. We assembled a data set of 233 taxa and 775 genes from which an optimally informative data set of 117 taxa and 129 genes was finally selected using new heuristics and compared with the unreduced data set. We included novel expressed sequence tag (EST) data for 11 species and all published phylogenomic data augmented by recently published EST data on taxonomically important arthropod taxa. This thorough sampling reduces the chance of obtaining spurious results due to stochastic effects of undersampling taxa and genes. Orthology prediction of genes, alignment masking tools, and selection of most informative genes due to a balanced taxa-gene ratio using new heuristics were established. Our optimized data set robustly resolves major arthropod relationships. We received strong support for a sister group relationship of onychophorans and euarthropods and strong support for a close association of tardigrades and cycloneuralia. Within pancrustaceans, our analyses yielded paraphyletic crustaceans and monophyletic hexapods and robustly resolved monophyletic endopterygote insects. However, our analyses also showed for few deep splits that were recently thought to be resolved, for example, the position of myriapods, a remarkable sensitivity to methods of analyses.
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Parametric and non-parametric masking of randomness in sequence alignments can be improved and leads to better resolved trees.
Front. Zool.
PUBLISHED: 03-31-2010
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Methods of alignment masking, which refers to the technique of excluding alignment blocks prior to tree reconstructions, have been successful in improving the signal-to-noise ratio in sequence alignments. However, the lack of formally well defined methods to identify randomness in sequence alignments has prevented a routine application of alignment masking. In this study, we compared the effects on tree reconstructions of the most commonly used profiling method (GBLOCKS) which uses a predefined set of rules in combination with alignment masking, with a new profiling approach (ALISCORE) based on Monte Carlo resampling within a sliding window, using different data sets and alignment methods. While the GBLOCKS approach excludes variable sections above a certain threshold which choice is left arbitrary, the ALISCORE algorithm is free of a priori rating of parameter space and therefore more objective.
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Hemocyanin suggests a close relationship of Remipedia and Hexapoda.
Mol. Biol. Evol.
PUBLISHED: 08-19-2009
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The Remipedia are enigmatic crustaceans from anchialine cave systems, first described only 30 years ago, whose phylogenetic affinities are as yet unresolved. Here we report the sequence of hemocyanin from Speleonectes tulumensis Yager, 1987 (Remipedia, Speleonectidae). This is the first proof of the presence of this type of respiratory protein in a crustacean taxon other than Malacostraca. Speleonectes tulumensis hemocyanin consists of multiple distinct (at least three) subunits (StuHc1-3; Hc, hemocyanin). Surprisingly, the sequences are most similar to hexapod hemocyanins. Phylogenetic analyses showed that the S. tulumensis hemocyanin subunits StuHc1 and StuHc3 associate with the type 1 hexapod hemocyanin subunits, whereas StuHc2 associates with the type 2 subunits of hexapods. Together, remipede and hexapod hemocyanins are in the sister-group position to the hemocyanins of malacostracan crustaceans. Hemocyanins provide no indication of a close relationship of Myriapoda and Hexapoda but support Pancrustacea (Crustacea + Hexapoda). Our results also suggest that Crustacea are paraphyletic and that Hexapoda may have evolved from a Remipedia-like ancestor. Thus, Remipedia occupy a key position for the understanding of the evolution of hexapods, which are and have been one of the worlds most speciose lineage of animals.
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Arthropod phylogeny revisited, with a focus on crustacean relationships.
Arthropod Struct Dev
PUBLISHED: 06-10-2009
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Higher-level arthropod phylogenetics is an intensely active field of research, not least as a result of the hegemony of molecular data. However, not all areas of arthropod phylogenetics have so far received equal attention. The application of molecular data to infer a comprehensive phylogeny of Crustacea is still in its infancy, and several emerging results are conspicuously at odds with morphology-based studies. In this study, we present a series of molecular phylogenetic analyses of 88 arthropods, including 57 crustaceans, representing all the major lineages, with Onychophora and Tardigrada as outgroups. Our analyses are based on published and new sequences for two mitochondrial markers, 16S rDNA and cytochrome c oxidase subunit I (COI), and the nuclear ribosomal gene 18S rDNA. We designed our phylogenetic analyses to assess the effects of different strategies of sequence alignment, alignment masking, nucleotide coding, and model settings. Our comparisons show that alignment optimization of ribosomal markers based on secondary structure information can have a radical impact on phylogenetic reconstruction. Trees based on optimized alignments recover monophyletic Arthropoda (excluding Onychophora), Pancrustacea, Malacostraca, Insecta, Myriapoda and Chelicerata, while Maxillopoda and Hexapoda emerge as paraphyletic groups. Our results are unable to resolve the highest-level relationships within Arthropoda, and none of our trees supports the monophyly of Myriochelata or Mandibulata. We discuss our results in the context of both the methodological variations between different analyses, and of recently proposed phylogenetic hypotheses. This article offers a preliminary attempt to incorporate the large diversity of crustaceans into a single molecular phylogenetic analysis, assessing the robustness of phylogenetic relationships under varying analysis parameters. It throws into sharp relief the relative strengths and shortcomings of the combined molecular data for assessing this challenging phylogenetic problem, and thereby provides useful pointers for future studies.
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Cationic composition and acid-base state of the extracellular fluid, and specific buffer value of hemoglobin from the branchiopod crustacean Triops cancriformis.
J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.
PUBLISHED: 06-02-2009
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Recent insights into the allosteric control of oxygen binding in the extracellular hemoglobin (Hb) of the tadpole shrimp Triops cancriformis raised the question about the physico-chemical properties of the proteins native environment. This study determined the cationic composition and acid-base state of the animals extracellular fluid. The physiological concentrations of potential cationic effectors (calcium, magnesium) were more than one order of magnitude below the level effective to increase Hb oxygen affinity. The extracellular fluid in the pericardial space had a typical bicarbonate concentration of 7.6 mM but a remarkably high CO(2) partial pressure of 1.36 kPa at pH 7.52 and 20 degrees C. The discrepancy between this high CO(2) partial pressure and the comparably low values for water-breathing decapods could not solely be explained by the hemolymph-sampling procedure but may additionally arise from differences in cardiovascular complexity and efficiency. T. cancriformis hemolymph had a non-bicarbonate buffer value of 2.1 meq L(-1) pH(-1). Hb covered 40-60% of the non-bicarbonate buffering power. The specific buffer value of Hb of 1.1 meq (mmol heme)(-1) pH(-1) suggested a minimum requirement of two titratable histidines per heme-binding domain, which is supported by available information from N-terminal sequencing and expressed sequence tags.
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Can comprehensive background knowledge be incorporated into substitution models to improve phylogenetic analyses? A case study on major arthropod relationships.
BMC Evol. Biol.
PUBLISHED: 05-27-2009
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Whenever different data sets arrive at conflicting phylogenetic hypotheses, only testable causal explanations of sources of errors in at least one of the data sets allow us to critically choose among the conflicting hypotheses of relationships. The large (28S) and small (18S) subunit rRNAs are among the most popular markers for studies of deep phylogenies. However, some nodes supported by this data are suspected of being artifacts caused by peculiarities of the evolution of these molecules. Arthropod phylogeny is an especially controversial subject dotted with conflicting hypotheses which are dependent on data set and method of reconstruction. We assume that phylogenetic analyses based on these genes can be improved further i) by enlarging the taxon sample and ii) employing more realistic models of sequence evolution incorporating non-stationary substitution processes and iii) considering covariation and pairing of sites in rRNA-genes.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.