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| 2. |
- Dnyansagar, R., et al.
(författare)
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Dispersal and speciation: The cross Atlantic relationship of two parasitic cnidarians
- 2018
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903. ; 126, s. 346-355
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Tidskriftsartikel (refereegranskat)abstract
- How dispersal strategies impact the distribution of species and subsequent speciation events is a fundamental question in evolutionary biology. Sedentary benthic marine organisms, such as corals or sea anemones usually rely on motile larval stages for dispersal and therefore have a relatively restricted distribution along coasts. Edwardsiella lineata and Edwardsiella carnea are virtually indistinguishable edwardsiid sea anemones native to the east American and the Northern European coast, respectively. E. lineata is a facultative parasite to the ctenophore Mnemiopsis leidyi, while the life cycle of E. carnea is unknown. Recently M. leidyi was found in the Skagerrak carrying Edwardsiella sp. parasites, which raised the intriguing possibility that the invasive comb jellies acted as cargo for the facultative E. lineata parasites to establish a new population in Northern Europe. Here, we assessed the genetic differences between these two cryptic Edwardsiella species and isolated parasites from the invasive comb jelly M. leidyi in Sweden by comparing rRNA, whole transcriptomes, SNPs, ITS2 sequences and the gene complements of key developmental regulators, the Wnt gene family. We show that E. carnea and the parasite transcriptomes are more than 99% identical, hence demonstrating that E. carnea has a previously unknown parasitic life stage. ITS2 sequence analysis of E. carnea and E. lineata suggest that they may not be reproductively isolated. The transcriptomes of E. lineata and E. carnea are similar to 97% identical. We also estimate that the species diverged between 18.7 and 21.6 million years ago.
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| 3. |
- Sundberg, Per, et al.
(författare)
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Utvärdering av ny övervakning av främmande arter : Metodjämförelse mellan traditionell och DNA-baserad identifiering
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport redovisar resultat från en studie där vi undersökt artförekomst och speciellt förekomst av invasiva främmande arter i kustmiljö. Syftet har varit att utvärdera konventionell undersökningsmetodik för att identifiera arter genom taxonomisk artbestämning genetisk identifiering genom DNAmetabarkodning, i hamnmiljöer.Genom att övervaka miljön med nya genetiska metoder får vi möjligheter att upptäcka spår av organismers förekomst, något som annars är svårt med sortering av organismer från vatten-/planktonprov, bottenhugg eller fiskeredskap. Utvecklingen av DNA-tekniker går fort och det ser lovande ut att tillämpa dessa i jakten på invasiva främmande arter och patogener som är skadliga för den biologiska mångfalden, människors och djurs hälsa samt orsakar stora samhällskostnader, alltså organismer som vi anser är invasiva och främmande.Det finns idag inga miljöövervakningsprogram som baseras på DNA. Samtidigt blir det allt svårare att hitta experter, så kallade taxonomer som kan identifiera arter och som oftast är specialiserade på en eller några artgrupper. Dessutom kommer många arter hit som larver eller juveniler som kanske inte alls liknar det vuxna djuret, eller algen, och därmed är svåra att artbestämma. Detta innebär att många arter kan komma hit utan att upptäckas förrän de är etablerade, och då har vi vanligtvis nått en situation då den invasiva främmande arten i fråga etablerat sig i en ny miljö, och därmed inte går att åtgärda.Såväl EU:s förordning om invasiva främmande arter som havsmiljödirektivet ställer krav på nationell övervakning av främmande arter. Och inom havsmiljöförvaltningen finns även behoven för att fullfölja arbetet med främmande arter inom Helcoms och Ospar. För att snabbt kunna utrota eller begränsa nyetableringar av invasiva främmande arter behöver vi utveckla metoder som är effektiva på att tidigt upptäcka nya introduktioner. Övervakning med hjälp av DNA-baserade metoder som metabarkodning är en lämplig väg att gå. Eftersom det är nya metoder för övervakning så bör även nya indikatorer tas fram som lämpar sig för genetiska metoder. Genetiska metoder bör ses som ett komplement till de traditionella – inte minst under en övergångsfas och om så möjligt ersätta traditionella.
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| 4. |
- Haenel, Quiterie, et al.
(författare)
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NGS-based biodiversity and community structure analysis of meiofaunal eukaryotes in shell sand from Hållö island, Smögen, and soft mud from Gullmarn Fjord, Sweden
- 2017
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Ingår i: Biodiversity Data Journal. - : Oleksandr Holovachov. - 1314-2828 .- 1314-2836. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- © Haenel Q et al. Aim: The aim of this study was to assess the biodiversity and community structure of Swedish meiofaunal eukaryotes using metabarcoding. To validate the reliability of the metabarcoding approach, we compare the taxonomic resolution obtained using the mitochondrial cytochrome oxidase 1 (COI) 'mini-barcode' and nuclear 18S small ribosomal subunit (18S) V1-V2 region, with traditional morphology-based identification of Xenacoelomorpha and Nematoda. Location: 30 samples were analysed from two ecologically distinct locations along the west coast of Sweden. 18 replicate samples of coarse shell sand were collected along the northeastern side of Hållö island near Smögen, while 12 replicate samples of soft mud were collected in the Gullmarn Fjord near Lysekil.
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| 5. |
- Andersson, Håkan S., 1967-, et al.
(författare)
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The toxicity of ribbon worms: alpha-nemertides or tetrodotoxin, or both?
- 2016
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Ingår i: Planta Medica. - : Georg Thieme Verlag KG. - 0032-0943 .- 1439-0221. ; 82:Supplement 1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The marine ribbon worms (nemerteans) are predators which capture their prey by everting a proboscis carrying a mixture of toxins which brings on rapid paralysis [1]. Moreover, ribbon worms have a thick layer of epidermal mucus of similar constitution. Tetrodotoxin (TTX) has been identified as one of these toxins [2]. The extreme toxicity of TTX (lethal by ingestion of 0.5-2 mg) is due to its ability to block voltage-gated sodium channels. Although several bacterial species (among these Vibrio sp.) have been linked to its synthesis, the biogenic origin and biosynthesis is unclear. One hypothesis is that TTX production occurs in a symbiotic relationship with its host, in this case the ribbon worm [3]. We have made significant effort to identify TTX in a setup for production through the cultivation of Vibrio alginolyticus in nutrient broth infused with mucus from the ribbon worm Lineus longissimus. Toxicity was demonstrated by fraction injections into shore crabs, but no TTX was found, and it could be shown conclusively that toxicity was unrelated to TTX and the Vibrio culture itself, and rather a constituent of the ribbon worm mucus [4]. The following studies led us to the discovery of a new class of peptides, the alpha-nemertides, in the mucus of the ribbon worms, which could be directly linked to the toxic effects. A literature review of the available evidence for TTX in ribbon worms show that the evidence in most cases are indirect, although notable exceptions exist. This points to the necessity to further investigate the presence and roles of TTX and alpha-nemertides in ribbon worms.
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| 6. |
- Bachmann, L., et al.
(författare)
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Systematics and biodiversity research in the era of genomics
- 2016
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Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 45, s. 3-4
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Tidskriftsartikel (refereegranskat)abstract
- On 5 November 2015, The Norwegian Academy of Sciences and Letters (DNVA) and the editors of the Zoologica Scripta invited to the one-day symposium ‘Systematics and Biodiversity Research in the Era of Genomics’. Some 80 scientists gathered at the premises of the DNVA in Oslo, Norway, to explore and discuss the current trends and future developments in the field of Animal Systematics. © 2016 The Authors. Zoologica Scripta published by John Wiley & Sons Ltd on behalf of Royal Swedish Academy of Sciences.
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| 7. |
- Seberg, Ole, et al.
(författare)
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Willi Hennig’s legacy in the Nordic countries
- 2016
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Ingår i: The Future of Phylogenetic Systematics: the Legacy of Willi Hennig. - Cambridge : Cambridge University Press.. - 9781107117648 ; , s. 21-30
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Strand, Malin, et al.
(författare)
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The Bacterial (Vibrio alginolyticus) Production of Tetrodotoxin in the Ribbon Worm Lineus longissimus-Just a False Positive?
- 2016
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Ingår i: Marine Drugs. - Basel : MDPI AG. - 1660-3397. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- We test previous claims that the bacteria Vibrio alginolyticus produces tetrodotoxin (TTX) when living in symbiosis with the nemertean Lineus longissimus by a setup with bacteria cultivation for TTX production. Toxicity experiments on the shore crab, Carcinus maenas, demonstrated the presence of a paralytic toxin, but evidence from LC-MS and electrophysiological measurements of voltage-gated sodium channel-dependent nerve conductance in maleWistar rat tissue showed conclusively that this effect did not originate from TTX. However, a compound of similar molecular weight was found, albeit apparently non-toxic, and with different LC retention time and MS/MS fragmentation pattern than those of TTX. We conclude that C. maenas paralysis and death likely emanate from a compound <5 kDa, and via a different mechanism of action than that of TTX. The similarity in mass between TTX and the Vibrio-produced low-molecular-weight, non-toxic compound invokes that thorough analysis is required when assessing TTX production. Based on our findings, we suggest that re-examination of some published claims of TTX production may be warranted.
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| 9. |
- Sundberg, Per, 1950, et al.
(författare)
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Evaluating the Utility of Single-Locus DNA Barcoding for the Identification of Ribbon Worms (Phylum Nemertea)
- 2016
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- Whereas many nemerteans (ribbon worms; phylum Nemertea) can be identified from external characters if observed alive, many are still problematic. When it comes to preserved specimens (as in e. g. marine inventories), there is a particular need for specimen identifier alternatives. Here, we evaluate the utility of COI (cytochrome c oxidase subunit I) as a single- locus barcoding gene. We sequenced, data mined, and compared gene fragments of COI for 915 individuals representing 161 unique taxonomic labels for 71 genera, and subjected different constellations of these to both distance-based and character-based DNA barcoding approaches, as well as species delimitation analyses. We searched for the presence or absence of a barcoding gap at different taxonomic levels (phylum, subclass, family and genus) in an attempt to understand at what level a putative barcoding gap presents itself. This was performed both using the taxonomic labels as species predictors and using objectively inferred species boundaries recovered from our species delimitation analyses. Our data suggest that COI works as a species identifier for most groups within the phylum, but also that COI data are obscured by misidentifications in sequence databases. Further, our results suggest that the number of predicted species within the dataset is (in some cases substantially) higher than the number of unique taxonomic labels-this highlights the presence of several cryptic lineages within well-established taxa and underscores the urgency of an updated taxonomic backbone for the phylum.
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| 10. |
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