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- Gustafsson, Malin, et al.
(författare)
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Unlocking the secret life of blue mussels: Exploring connectivity in the Skagerrak through biophysical modeling and population genomics
- 2024
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Ingår i: Evolutionary Applications. - 1752-4571. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of functional dispersal barriers in the marine environment can be used to inform a wide variety of management actions, such as marine spatial planning, restoration efforts, fisheries regulations, and invasive species management. Locations and causes of dispersal barriers can be studied through various methods, including movement tracking, biophysical modeling, demographic models, and genetics. Combining methods illustrating potential dispersal, such as biophysical modeling, with realized dispersal through, e.g., genetic connectivity estimates, provides particularly useful information for teasing apart potential causes of observed barriers. In this study, we focus on blue mussels (Mytilus edulis) in the Skagerrak—a marginal sea connected to the North Sea in Northern Europe—and combine biophysical models of larval dispersal with genomic data to infer locations and causes of dispersal barriers in the area. Results from both methods agree; patterns of ocean currents are a major structuring factor in the area. We find a complex pattern of source-sink dynamics with several dispersal barriers and show that some areas can be isolated despite an overall high dispersal capability. Finally, we translate our finding into management advice that can be used to sustainably manage this ecologically and economically important species in the future.
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| 2. |
- Alfaya, J. E. F., et al.
(författare)
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DNA barcoding supports identification of Malacobdella species (Nemertea: Hoplonemertea)
- 2015
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Ingår i: Zoological Studies. - : Springer Science and Business Media LLC. - 1021-5506 .- 1810-522X. ; 54
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Tidskriftsartikel (refereegranskat)abstract
- Background: Nemerteans of the genus Malacobdella live inside of the mantle cavity of marine bivalves. The genus currently contains only six species, five of which are host-specific and usually found in a single host species, while the sixth species, M. grossa, has a wide host range and has been found in 27 different bivalve species to date. The main challenge of Malacobdella species identification resides in the similarity of the external morphology between species (terminal sucker, gut undulations number, anus position and gonad colouration), and thus, the illustrations provided in the original descriptions do not allow reliable identification. In this article, we analyse the relationships among three species of Malacobdella: M. arrokeana, M. japonica and M. grossa, adding new data for the M. grossa and reporting the first for M. japonica, analysing 658 base pairs of the mitochondrial cytochrome c oxidase subunit I gene (COI). Based on these analyses, we present and discuss the potential of DNA barcoding for Malacobdella species identification. Results: Sixty-four DNA barcoding fragments of the mitochondrial COI gene from three different Malacobdella species (M. arrokeana, M. japonica and M. grossa) are analysed (24 of them newly sequenced for this study, along with four outgroup specimens) and used to delineate species. Divergences, measured as uncorrected differences, between the three species were M. arrokeana-M. grossa 11.73%, M. arrokeana-M. japonica 10.62% and M. grossa-M. japonica 10.97%. The mean intraspecific divergence within the ingroup species showed a patent gap with respect to the interspecific ones: 0.18% for M. arrokeana, 0.13% for M. grossa and 0.02% for M. japonica (ranges from 0 to 0.91%). Conclusions: We conclude that there is a clear correspondence between the molecular data and distinguishing morphological characters. Our results thus indicate that some morphological characters are useful for species identification and support the potential of DNA barcoding for species identification in a taxonomic group with subtle morphological external differences.
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| 4. |
- Alsved, Malin, et al.
(författare)
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Sources of Airborne Norovirus in Hospital Outbreaks
- 2020
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1537-6591 .- 1058-4838. ; 70:10, s. 2023-2028
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Noroviruses are the major cause of viral gastroenteritis. Disease transmission is difficult to prevent and outbreaks in healthcare facilities commonly occur. Contact with infected persons and contaminated environments are believed to be the main routes of transmission. However, noroviruses have recently been found in aerosols and airborne transmission has been suggested. The aim of our study was to investigate associations between symptoms of gastroenteritis and presence of airborne norovirus, and to investigate the size of norovirus carrying particles.METHODS: Air sampling was repeatedly performed close to 26 patients with norovirus infections. Samples were analysed for norovirus RNA by RT-qPCR. The times since the patients' last episodes of vomiting and diarrhoea were recorded. Size separating aerosol particle collection was also performed in ward corridors.RESULTS: Norovirus RNA was found in 21 (24%) of 86 air samples from 10 different patients. Only air samples during outbreaks, or before a succeeding outbreak, tested positive for norovirus RNA. Airborne norovirus RNA was also strongly associated with a shorter time period since the last vomiting episode (odds ratio 8.1, p=0.04 within 3 hours since the last vomiting episode). The concentration of airborne norovirus ranged from 5-215 copies/m3, and detectable amounts of norovirus RNA were found in particles <0.95 µm and >4.51 µm.CONCLUSIONS: The results suggest that recent vomiting is the major source of airborne norovirus and imply a connection between airborne norovirus and outbreaks. The presence of norovirus RNA in submicrometre particles indicates that airborne transmission can be an important transmission route.
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| 6. |
- Andersson, Håkan S., 1967-, et al.
(författare)
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Alpha-nemertides - a novel family of nemertean peptide neurotoxins
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We recently discovered a novel family of neuroactive peptides in nemerteans, which we have named alpha-nemertides (1). One of these peptides, nemertide alpha-1, has been the subject of detailed studies with regard to structure and effects. The peptide exhibits exceptional potency against a number of arthropod species. Moreover, in vitro experiments suggest that alpha-1 acts primarily on voltage-gated sodium channels, and that this action is selective for arthropods by two orders of magnitude over vertebrate species. Using transcriptomic and proteomic approaches, we have identified 10 alpha-nemertides, but this number is likely to increase. These peptides alongside with a series of mutants are currently under evaluation by our group, with the goal to improve our understanding of structure-function relationships. In addition, we are considering potential practical uses of alpha-nemertides. In this talk, I will describe the current status of this research project.1. E. Jacobsson et al., Peptide ion channel toxins from the bootlace worm, the longest animal on Earth. Scientific reports 8, 4596 (2018).
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| 7. |
- Andersson, Håkan S., 1967-, et al.
(författare)
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Discovery of novel ion-channel active peptide toxins in a North Sea Ribbon Worm
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ribbon worms (nemerteans) are marine predators, which capture their prey using a proboscis containing a mixture of toxins which brings on rapid paralysis [1]. In addition, their epidermis contains thick mucus of similar toxic constitution. One very potent toxin reported in ribbon worm mucus is tetrodotoxin (TTX). However, despite significant efforts, Strand et al. [2] were unable to detect any TTX, neither in the mucus of the ribbon worm Lineus longissimus, nor from Vibrio alginolyticus cultures isolated from and cultivated in the mucus. These observations challenged the notion of general presence of TTX in ribbon worm mucus, and prompted us to look for other toxins [3]. Using LC-MS analysis of mucus extracts, we identified three peptides present in significant amounts. The peptides were sequenced using a combination of MS/MS analysis and transcriptomics, and whereas one of them strongly resembles the only peptide toxin previously characterized from ribbon worms, Neurotoxin B-IV [4], the other two were found to represent a previously unknown class of peptide toxins. The most abundant of these was synthesized, and its 3D structure determined. Preliminary toxicity tests on shore crab (C. maenas) indicated toxicity (through paralysis) on par with that of TTX. Further analyses have indicated that its toxic effects are due to binding to voltage sensitive sodium channels. With L. longissimus as our primary target, we are now mapping the presence of peptide toxins in ribbon worms, with the objectives to establish routes for synthesis, and to characterize the biological activities and structures of these peptides. The number of peptides of this novel class is increasing, and synthesis and characterization is well underway. The striking potencies of these peptides make them potentially amenable as novel insecticidal or anthelmintic leads, pharmacological tools or in biotechnology applications. References1. Strand M, Sundberg P. Nationalnyckeln till Sveriges flora och fauna [DO-DP]. Stjärnmaskar-Slemmaskar: Sipuncula-Nemertea: Artdatabanken, SLU; 2010.2. Strand M, Hedstrom M, Seth H, McEvoy EG, Jacobsson E, Goransson U, Andersson HS, Sundberg P. The Bacterial (Vibrio alginolyticus) Production of Tetrodotoxin in the Ribbon Worm Lineus longissimus-Just a False Positive? Marine Drugs. 2016;14(4).3. Strand M, Andersson HS. Slemmaskens hemlighet. Forskning & Framsteg. 2016;(2):26-33.4. Blumenthal KM, Kem WR. Structure and action of heteronemertine polypeptide toxins. Primary structure of Cerebratulus lacteus toxin B-IV. The Journal of Biological Chemistry. 1976;251(19):6025-9.
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