118 research outputs found
Anatomy and the type concept in biology show that ontologies must be adapted to the diagnostic needs of research
Background: In times of exponential data growth in the life sciences, machine-supported approaches are becoming increasingly important and with them the need for FAIR (Findable, Accessible, Interoperable, Reusable) and eScience-compliant data and metadata standards. Ontologies, with their queryable knowledge resources, play an essential role in providing these standards. Unfortunately, biomedical ontologies only provide ontological definitions that answer What is it? questions, but no method-dependent empirical recognition criteria that answer How does it look? questions. Consequently, biomedical ontologies contain knowledge of the underlying ontological nature of structural kinds, but often lack sufficient diagnostic knowledge to unambiguously determine the reference of a term. Results: We argue that this is because ontology terms are usually textually defined and conceived as essentialistic classes, while recognition criteria often require perception-based definitions because perception-based contents more efficiently document and communicate spatial and temporal information—a picture is worth a thousand words. Therefore, diagnostic knowledge often must be conceived as cluster classes or fuzzy sets. Using several examples from anatomy, we point out the importance of diagnostic knowledge in anatomical research and discuss the role of cluster classes and fuzzy sets as concepts of grouping needed in anatomy ontologies in addition to essentialistic classes. In this context, we evaluate the role of the biological type concept and discuss its function as a general container concept for groupings not covered by the essentialistic class concept. Conclusions: We conclude that many recognition criteria can be conceptualized as text-based cluster classes that use terms that are in turn based on perception-based fuzzy set concepts. Finally, we point out that only if biomedical ontologies model also relevant diagnostic knowledge in addition to ontological knowledge, they will fully realize their potential and contribute even more substantially to the establishment of FAIR and eScience-compliant data and metadata standards in the life sciences
Anatomy and the type concept in biology show that ontologies must be adapted to the diagnostic needs of research
Background: In times of exponential data growth in the life sciences, machine-supported approaches are becoming increasingly important and with them the need for FAIR (Findable, Accessible, Interoperable, Reusable) and eScience-compliant data and metadata standards. Ontologies, with their queryable knowledge resources, play an essential role in providing these standards. Unfortunately, biomedical ontologies only provide ontological definitions that answer What is it? questions, but no method-dependent empirical recognition criteria that answer How does it look? questions. Consequently, biomedical ontologies contain knowledge of the underlying ontological nature of structural kinds, but often lack sufficient diagnostic knowledge to unambiguously determine the reference of a term. Results: We argue that this is because ontology terms are usually textually defined and conceived as essentialistic classes, while recognition criteria often require perception-based definitions because perception-based contents more efficiently document and communicate spatial and temporal information—a picture is worth a thousand words. Therefore, diagnostic knowledge often must be conceived as cluster classes or fuzzy sets. Using several examples from anatomy, we point out the importance of diagnostic knowledge in anatomical research and discuss the role of cluster classes and fuzzy sets as concepts of grouping needed in anatomy ontologies in addition to essentialistic classes. In this context, we evaluate the role of the biological type concept and discuss its function as a general container concept for groupings not covered by the essentialistic class concept. Conclusions: We conclude that many recognition criteria can be conceptualized as text-based cluster classes that use terms that are in turn based on perception-based fuzzy set concepts. Finally, we point out that only if biomedical ontologies model also relevant diagnostic knowledge in addition to ontological knowledge, they will fully realize their potential and contribute even more substantially to the establishment of FAIR and eScience-compliant data and metadata standards in the life sciences
Mitochondrial sequence data expose the putative cosmopolitan polychaete Scoloplos armiger (Annelida, Orbiniidae) as a species complex
Background
Polychaetes assigned as Scoloplos armiger (Orbiniidae) show a cosmopolitan distribution and have been encountered in all zoogeographic regions. Sibling S. armiger-like species have been revealed by recent studies using RAPDs and AFLP genetic data. We sequenced a ~12 kb fragment of the Scoloplos cf. armiger mitochondrial genome and developed primers for variable regions including the 3' end of the cox3 gene, trnQ, and most of nad6. A phylogenetic analysis of this 528-nucleotide fragment was carried out for S. armiger-like individuals from the Eastern North Atlantic as well as Pacific regions. The aim of this study is to test the cosmopolitan status, as well as to clarify the systematics of this species complex in the Eastern North Atlantic, while using a few specimens from the Pacific Ocean for comparision.
Results
Phylogenetic analysis of the cox3-trnQ-nad6 data set recovered five different clades of Scoloplos cf. armiger. The fragment of the mitochondrial genome of Scoloplos cf. armiger is 12,042 bp long and contains 13 protein coding genes, 15 of the 22 expected tRNAs, and the large ribosomal subunit (rrnl).
Conclusion
The sequenced cox3-trnQ-nad6 fragment proved to be very useful in phylogenetic analyses of Scoloplos cf. armiger. Due to its larger sampling scale this study goes beyond previous analyses which used RAPD and AFLP markers. The results of this study clearly supports that Scoloplos armiger represents a species complex and not a cosmopolitan species. We find at least two S. armiger-like species within the Pacific region and three different S. armiger-like species in the North Atlantic. Implications for the taxonomy and the impact on ecological studies are discussed
Systematic comparison and reconstruction of sea urchin (Echinoidea) internal anatomy: a novel approach using magnetic resonance imaging
<p>Abstract</p> <p>Background</p> <p>Traditional comparative morphological analyses and subsequent three-dimensional reconstructions suffer from a number of drawbacks. This is particularly evident in the case of soft tissue studies that are technically demanding, time-consuming, and often prone to produce artefacts. These problems can partly be overcome by employing non-invasive, destruction-free imaging techniques, in particular micro-computed tomography or magnetic resonance imaging.</p> <p>Results</p> <p>Here, we employed high-field magnetic resonance imaging techniques to gather numerous data from members of a major marine invertebrate taxon, the sea urchins (Echinoidea). For this model study, 13 of the 14 currently recognized high-ranking subtaxa (orders) of this group of animals were analyzed. Based on the acquired datasets, interactive three-dimensional models were assembled. Our analyses reveal that selected soft tissue characters can even be used for phylogenetic inferences in sea urchins, as exemplified by differences in the size and shape of the gastric caecum found in the Irregularia.</p> <p>Conclusion</p> <p>The main focus of our investigation was to explore the possibility to systematically visualize the internal anatomy of echinoids obtained from various museum collections. We show that, in contrast to classical preparative procedures, magnetic resonance imaging can give rapid, destruction-free access to morphological data from numerous specimens, thus extending the range of techniques available for comparative studies of invertebrate morphology.</p
Phylogeny and mitochondrial gene order variation in Lophotrochozoa in the light of new mitogenomic data from Nemertea
<p>Abstract</p> <p>Background</p> <p>The new animal phylogeny established several taxa which were not identified by morphological analyses, most prominently the Ecdysozoa (arthropods, roundworms, priapulids and others) and Lophotrochozoa (molluscs, annelids, brachiopods and others). Lophotrochozoan interrelationships are under discussion, e.g. regarding the position of Nemertea (ribbon worms), which were discussed to be sister group to e.g. Mollusca, Brachiozoa or Platyhelminthes. Mitochondrial genomes contributed well with sequence data and gene order characters to the deep metazoan phylogeny debate.</p> <p>Results</p> <p>In this study we present the first complete mitochondrial genome record for a member of the Nemertea, <it>Lineus viridis</it>. Except two <it>trnP </it>and <it>trnT</it>, all genes are located on the same strand. While gene order is most similar to that of the brachiopod <it>Terebratulina retusa</it>, sequence based analyses of mitochondrial genes place nemerteans close to molluscs, phoronids and entoprocts without clear preference for one of these taxa as sister group.</p> <p>Conclusion</p> <p>Almost all recent analyses with large datasets show good support for a taxon comprising Annelida, Mollusca, Brachiopoda, Phoronida and Nemertea. But the relationships among these taxa vary between different studies. The analysis of gene order differences gives evidence for a multiple independent occurrence of a large inversion in the mitochondrial genome of Lophotrochozoa and a re-inversion of the same part in gastropods. We hypothesize that some regions of the genome have a higher chance for intramolecular recombination than others and gene order data have to be analysed carefully to detect convergent rearrangement events.</p
The central nervous system of Oweniidae (Annelida) and its implications for the structure of the ancestral annelid brain
Figure S1: Histology Orrhageâs Owenia fusiformis. A: slide showing sections of Owenia fusiformis. B: Intermediate filaments (if) cross the neuropil of the brain (br). The ecm of the epidermis is less prominent where the neuropil layer is above it. C: Posterior part of the brain (br). if: intermediate filaments. (JPG 10649 kb
Mitochondrial genome sequence and gene order of Sipunculus nudus give additional support for an inclusion of Sipuncula into Annelida
<p>Abstract</p> <p>Background</p> <p>Mitochondrial genomes are a valuable source of data for analysing phylogenetic relationships. Besides sequence information, mitochondrial gene order may add phylogenetically useful information, too. Sipuncula are unsegmented marine worms, traditionally placed in their own phylum. Recent molecular and morphological findings suggest a close affinity to the segmented Annelida.</p> <p>Results</p> <p>The first complete mitochondrial genome of a member of Sipuncula, <it>Sipunculus nudus</it>, is presented. All 37 genes characteristic for metazoan mtDNA were detected and are encoded on the same strand. The mitochondrial gene order (protein-coding and ribosomal RNA genes) resembles that of annelids, but shows several derivations so far found only in Sipuncula. Sequence based phylogenetic analysis of mitochondrial protein-coding genes results in significant bootstrap support for Annelida <it>sensu lato</it>, combining Annelida together with Sipuncula, Echiura, Pogonophora and Myzostomida.</p> <p>Conclusion</p> <p>The mitochondrial sequence data support a close relationship of Annelida and Sipuncula. Also the most parsimonious explanation of changes in gene order favours a derivation from the annelid gene order. These results complement findings from recent phylogenetic analyses of nuclear encoded genes as well as a report of a segmental neural patterning in Sipuncula.</p
Protective Effects of Short-Chain Fatty Acids on Endothelial Dysfunction Induced by Angiotensin II
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fphys.2020.00277/full#supplementary-materialShort-chain fatty acids (SCFAs) are among the main classes of bacterial metabolic products and are mainly synthesized in the colon through bacterial fermentation. Short-chain fatty acids, such as acetate, butyrate, and propionate, reduce endothelial activation induced by proinflammatory mediators, at least in part, by activation of G protein–coupled receptors (GPRs): GPR41 and GPR43. The objective of the study was to analyze the possible protective effects of SCFAs on endothelial dysfunction induced by angiotensin II (AngII). Rat aortic endothelial cells (RAECs) and rat aortas were incubated with AngII (1 μM) for 6 h in the presence or absence of SCFAs (5–10 mM). In RAECs, we found that AngII reduces the production of nitric oxide (NO) stimulated by calcium ionophore A23187; increases the production of reactive oxygen species (ROS), both from the nicotinamide adenine dinucleotide phosphate oxidase system and the mitochondria; diminishes vasodilator-stimulated phosphoprotein (VASP) phosphorylation at Ser239; reduces GPR41 and GPR43 mRNA level; and reduces the endothelium-dependent relaxant response to acetylcholine in aorta. Coincubation with butyrate and acetate, but not with propionate, increases both NO production and pSer239-VASP, reduces the concentration of intracellular ROS, and improves relaxation to acetylcholine. The beneficial effects of butyrate were inhibited by the GPR41 receptor antagonist, β-hydroxybutyrate, and by the GPR43 receptor antagonist, GLPG0794. Butyrate inhibited the down-regulation of GPR41 and GPR43 induced by AngII, being without effect acetate and propionate. Neither β-hydroxybutyrate nor GLPG0794 affects the protective effect of acetate in endothelial dysfunction. In conclusion, acetate and butyrate improve endothelial dysfunction induced by AngII by increasing the bioavailability of NO. The effect of butyrate seems to be related to GPR41/43 activation, whereas acetate effects were independent of GPR41/43.Comision Interministerial de Ciencia y Tecnologia, Ministerio de Economia y competitividad
SAF2017-8489-RJunta de Andalucia
CTS164European Union (EU)Ministerio de Economia y competitividad, Instituto de Salud Carlos III (CIBER-CV), Spai
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