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Peters L, Spatharis S, Dario MA, Dwyer T, Roca IJT, Kintner A, Kanstad-Hanssen Ø, Llewellyn MS, Praebel K. Environmental DNA: A New Low-Cost Monitoring Tool for Pathogens in Salmonid Aquaculture. Front Microbiol 2018; 9:3009. [PMID: 30581425 PMCID: PMC6292926 DOI: 10.3389/fmicb.2018.03009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 11/20/2018] [Indexed: 01/17/2023] Open
Abstract
Environmental DNA (eDNA) metabarcoding is a relatively new monitoring tool featuring in an increasing number of applications such as the facilitation of the accurate and cost effective detection of species in environmental samples. eDNA monitoring is likely to have a major impact on the ability of salmonid aquaculture industry producers and their regulators to detect the presence and abundance of pathogens and other biological threats in the surrounding environment. However, for eDNA metabarcoding to develop into a useful bio-monitoring tool it is necessary to (a) validate that sequence datasets derived from amplification of metabarcoding markers reflect the true species' identity, (b) test the sensitivity under different abundance levels and environmental noise and (c) establish a low-cost sequencing method to enable the bulk processing of field samples. In this study, we employed an elaborate experimental design whereby different combinations of five biological agents were crossed at three abundance levels and exposed to sterile pre-filtered and unfiltered seawater, prior to coarse filtering and then eDNA ultrafiltration of the resultant material. We then benchmarked the low-cost, scalable, Ion Torrent sequencing method against the current gold-standard Illumina platform for eDNA surveys in aquaculture. Based on amplicon-seq of the 18S SSU rDNA v9 region, we were able to identify two parasites (Lepeophtheirus salmonis and Paramoeba perurans) to species level, whereas the microalgae species Prymnesium parvum, Pseudo-nitzschia seriata, and P. delicatissima could be assigned correctly only to the genus level. Illumina and Ion Torrent provided near identical results in terms of community composition in our samples, whereas Ion Torrent was more sensitive in detecting species richness when the medium was unfiltered seawater. Both methods were able to reflect the difference in relative abundance between treatments in 4 out of 5 species when samples were exposed to the unfiltered seawater, despite the significant amount of background noise from both bacteria and eukaryotes. Our findings indicate that eDNA metabarcoding offers significant potential in the monitoring of species harmful to aquaculture and for this purpose, the low-cost Ion Torrent sequencing is as accurate as Illumina in determining differences in their relative abundance between samples.
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Affiliation(s)
- Lucy Peters
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Sofie Spatharis
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- School of Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Maria Augusta Dario
- Laboratório de Biologia de Tripanosomatídeos, Instituto Oswaldo Cruz (IOC/Fiocruz), Rio de Janeiro, Brazil
| | - Toni Dwyer
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Inaki J. T. Roca
- Norwegian College of Fishery Science, University of Tromsø, Tromsø, Norway
| | - Anna Kintner
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | | | - Martin S. Llewellyn
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Kim Praebel
- Norwegian College of Fishery Science, University of Tromsø, Tromsø, Norway
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Harðardóttir S, Pančić M, Tammilehto A, Krock B, Møller EF, Nielsen TG, Lundholm N. Dangerous Relations in the Arctic Marine Food Web: Interactions between Toxin Producing Pseudo-nitzschia Diatoms and Calanus Copepodites. Mar Drugs 2015; 13:3809-35. [PMID: 26087022 PMCID: PMC4483658 DOI: 10.3390/md13063809] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/28/2015] [Indexed: 11/16/2022] Open
Abstract
Diatoms of the genus Pseudo-nitzschia produce domoic acid (DA), a toxin that is vectored in the marine food web, thus causing serious problems for marine organisms and humans. In spite of this, knowledge of interactions between grazing zooplankton and diatoms is restricted. In this study, we examined the interactions between Calanus copepodites and toxin producing Pseudo-nitzschia. The copepodites were fed with different concentrations of toxic P. seriata and a strain of P. obtusa that previously was tested to be non-toxic. The ingestion rates did not differ among the diets (P. seriata, P. obtusa, a mixture of both species), and they accumulated 6%–16% of ingested DA (up to 420 µg per dry weight copepodite). When P. seriata was exposed to the copepodites, either through physical contact with the grazers or separated by a membrane, the toxicity of P. seriata increased (up to 3300%) suggesting the response to be chemically mediated. The induced response was also triggered when copepodites grazed on another diatom, supporting the hypothesis that the cues originate from the copepodite. Neither pH nor nutrient concentrations explained the induced DA production. Unexpectedly, P. obtusa also produced DA when exposed to grazing copepodites, thus representing the second reported toxic polar diatom.
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Affiliation(s)
- Sara Harðardóttir
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307 Copenhagen, Denmark.
- National Institute of Aquatic Resources, Technical University of Denmark, Charlottenlund Slot, Jægersborg Allé 1, 2920 Charlottenlund, Denmark.
| | - Marina Pančić
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307 Copenhagen, Denmark.
- National Institute of Aquatic Resources, Technical University of Denmark, Charlottenlund Slot, Jægersborg Allé 1, 2920 Charlottenlund, Denmark.
| | - Anna Tammilehto
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307 Copenhagen, Denmark.
| | - Bernd Krock
- Alfred-Wegener-Institut für Polar- und Meeresforschung, Ökologische Chemie, Am Handelshafen 12, 27570 Bremerhaven, Germany.
| | - Eva Friis Møller
- Arctic Research Center, Department of Bioscience, Roskilde, Aarhus University, Frederiksborgvej 399, P.O. Box 358, 4000 Roskilde, Denmark.
| | - Torkel Gissel Nielsen
- National Institute of Aquatic Resources, Technical University of Denmark, Charlottenlund Slot, Jægersborg Allé 1, 2920 Charlottenlund, Denmark.
| | - Nina Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, 1307 Copenhagen, Denmark.
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Tammilehto A, Nielsen TG, Krock B, Møller EF, Lundholm N. Induction of domoic acid production in the toxic diatom Pseudo-nitzschia seriata by calanoid copepods. Aquat Toxicol 2015; 159:52-61. [PMID: 25521565 DOI: 10.1016/j.aquatox.2014.11.026] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 11/26/2014] [Accepted: 11/28/2014] [Indexed: 05/11/2023]
Abstract
The toxic diatom Pseudo-nitzschia seriata was exposed directly and indirectly (separated by a membrane) to copepods, Calanus hyperboreus and C. finmarchicus, to evaluate the effects of the copepods on domoic acid production and chain formation in P. seriata. The toxicity of P. seriata increased in the presence of the copepods. This response was chemically mediated without physical contact between the organisms suggesting that it was induced by potential waterborne cues from the copepods or changes in water chemistry. Domoic acid production may be related to defense against grazing in P. seriata although it was not shown in the present study. To evaluate if the induction of domoic acid production was mediated by the chemical cues from damaged P. seriata cells, live P. seriata cells were exposed to a P. seriata cell homogenate, but no effect was observed. Chain formation in P. seriata was affected only when in direct contact with the copepods. This study suggests that the presence of zooplankton may be one of the factors affecting the toxicity of Pseudo-nitzschia blooms in the field.
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Affiliation(s)
- Anna Tammilehto
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, DK-1307 Copenhagen K, Denmark.
| | - Torkel Gissel Nielsen
- National Institute of Aquatic Resources, DTU Aqua, Section for Oceanecology and Climate, Technical University of Denmark, DTU, Kavalergården 6, DK-2920 Charlottenlund, Denmark; Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland.
| | - Bernd Krock
- Alfred Wegener Institut-Helmholtz Zentrum für Polar- und Meeresforschung, Ökologische Chemie, Am Handelshafen 12, 27570 Bremerhaven, Germany.
| | - Eva Friis Møller
- Department of Bioscience, Roskilde, Aarhus University, Frederiksborgvej 399, PO Box 358, 4000 Roskilde, Denmark.
| | - Nina Lundholm
- Natural History Museum of Denmark, University of Copenhagen, Sølvgade 83S, DK-1307 Copenhagen K, Denmark.
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