Sequence comparisons link toxic European isolates of Alexandrium tamarense from the Orkney Islands to toxic North American stocks

Medlin, Linda K.; Lange, Martin; Wellbrock, Ursula; Donner, Georg; Elbrächter, Malte; Hummert, Christian; Luckas, Bernd

doi:10.1016/s0932-4739(98)80060-6

Cited by 60 publications

(52 citation statements)

References 11 publications

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“…On a global scale, the Scottish east coast populations found near the Orkney Islands are more closely related to Japanese Pacific isolates than to populations on the east coast of North America, which suggests that the Orkney populations were introduced to that region by cells transported directly across the Arctic Ocean. This interpretation is in contrast to the hypothesis put forward by Medlin et al (1998) that these populations entered from the Pacific and moved along coastal pathways of the eastern side of North America until they reached the Gulf Stream, which carried them across to the Scottish east coast. Moving to the diversity of local populations, at one site off the Orkney Islands, four populations were discovered that could interbreed, and these populations were proposed to represent different year classes that had hatched from local cyst beds (Alpermann et al, 2010).…”

Section: Population Genetics and Bloom Dynamicscontrasting

confidence: 88%

Biodiversity of Harmful Marine Algae

Medlin

Cembella

2013

Encyclopedia of Biodiversity

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Section: Population Genetics and Bloom Dynamicscontrasting

confidence: 88%

Biodiversity of Harmful Marine Algae

Medlin

Cembella

2013

Encyclopedia of Biodiversity

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“…Populations belonging to different clades of the A. tamarense species complex are found in European waters (Medlin et aI., 1998;John et al, submitted). In addition to the two toxic Alexandrium clades described from North American and temperate Asian regions (Medlin et al, 1998), populations belonging to the non-toxic Western European and Mediterranean clades (John et al, 2002 submitted) have been identified in Europe. Given this complexity, it was critical to design alternative rONA probes with different hybridization specificities for application to European field populations of A. tamarense.…”

Section: Discussionmentioning

confidence: 99%

“…Conditions for PCR were as described in Chesnick et al (1997) and Medlin et al (1998) for the 18S and 28S rRNA genes, respectively. Up to three PCR products were pooled and cleaned with a PCR purification kit (Qiagen, Hilden, Germany) and sequenced with the Long Read kit (Biozym, Hessisch Oldendorf, Germany) and a LiCor 4000L automatic sequencer (MWG, Ebersberg, Germany), with the same primers as in the PCR for the 28S rRNA and internal primers for the 18S rRNA gene (Elwood et al, 1985).…”

Section: Dna Preparationmentioning

confidence: 99%

Discrimination of the toxigenic dinoflagellatesAlexandrium tamarenseandA. ostenfeldiiin co-occurring natural populations from Scottish coastal waters

John

Cembella

Hummert³

et al. 2003

European Journal of Phycology

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119

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Blooms of the toxic dinoflagellate Alexandrium tamarense (Lebour) Balech, a known producer of potent neurotoxins associated with paralytic shellfish poisoning (PSP), are common annual events along the Scottish east coast. The cooccurrence of a second Alexandrium species, A. ostenfeldii (Paulsen) Balech & Tangen is reported in this study from waters of the Scottish east coast. The latter species has been suspected to be an alternative source of PSP toxins in northern Europe. Recent identification of toxic macrocyclic imines known as spirolides in A. ostenfeldii indicates a potential new challenge for monitoring toxic Alexandrium species and their respective toxins in natural populations. In mixed phytoplankton assemblages, A/exandrium species are difficult to discriminate accurately by convention~llight microscopy.Species-specific rRNA probes based upon 18S and 28S ribosomal DNA sequences were developed for A. ostenfeldii and tested by dot-blot and fluorescence in situ hybridization (FISH) techniques. Hybridization patterns of A. ostenfeldii probes for cultured A/exandrium isolates, and cells from field populations from the Scottish east coast, were compared with those of rONA probes fOf A. tamarense and a universal dinoflagellate probe. A/exandrium cell numbers in field samples determined by whole-cell in situ hybridization were much lower than those determined by optical microscopy with the Utermohl-~ethod involving sedimentation chambers, but the results were highly correlated (e.g. r 2 =0.94; n =6 for A. tamarense).Determination of spirolides and PSP toxins by instrumental analysis on board ship demonstrated the presence of both toxin groups in plankton assemblages collected from surface waters near the Orkney Islands, and confirmed the association of A. ostenfeldii with spirolides in northern Europe. These results show that rRNA probes for A. tamarense and A. ostenfe/dii are useful, albeit only semi-quantitative, tools to detect and discriminate these species in field studies.

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“…Because of the genetic diversity of different genera and species (30,33,38,41), molecular tools may be very useful for the detection of a microorganism, both in seawater and in sedi-ment (5,22,43,49,51). Because of their rapidity, PCR-based methods are used more and more.…”

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confidence: 99%

Development of a Real-Time PCR Assay for Rapid Detection and Quantification ofAlexandrium minutum(a Dinoflagellate)

Galluzzi

Penna

Bertozzini

et al. 2004

Appl Environ Microbiol

260

214

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The marine dinoflagellate genus Alexandrium includes a number of species which produce neurotoxins responsible for paralytic shellfish poisoning (PSP), which in humans may cause muscular paralysis, neurological symptoms, and, in extreme cases, death. A. minutum is the most widespread toxic PSP species in the western Mediterranean basin. The monitoring of coastal waters for the presence of harmful algae also normally involves microscopic examinations of phytoplankton populations. These procedures are time consuming and require a great deal of taxonomic experience, thus limiting the number of specimens that can be analyzed. Because of the genetic diversity of different genera and species, molecular tools may also help to detect the presence of target microorganisms in marine field samples. In this study, we developed a real-time PCR-based assay for rapid detection of all toxic species of the Alexandrium genus in both fixative-preserved environmental samples and cultures. Moreover, we developed a real-time quantitative PCR assay for the quantification of A. minutum cells in seawater samples. Alexandrium genus-specific primers were designed on the 5.8S rDNA region. Primer specificity was confirmed by using BLAST and by amplification of a representative sample of the DNA of other dinoflagellates and diatoms. Using a standard curve constructed with a plasmid containing the ITS1-5.8S-ITS2 A. minutum sequence and cultured A. minutum cells, we determined the absolute number of 5.8S rDNA copies per cell. Consequently, after quantification of 5.8S rDNA copies in samples containing A. minutum cells, we were also able to estimate the number of cells. Several fixed A. minutum bloom sea samples from Arenys Harbor (Catalan Coast, Spain) were analyzed using this method, and quantification results were compared with standard microscopy counting methods. The two methods gave comparable results, confirming that real-time PCR could be a valid, fast alternative procedure for the detection and quantification of target phytoplankton species during coastal water monitoring.

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Sequence comparisons link toxic European isolates of Alexandrium tamarense from the Orkney Islands to toxic North American stocks

Cited by 60 publications

References 11 publications

Biodiversity of Harmful Marine Algae

Biodiversity of Harmful Marine Algae

Discrimination of the toxigenic dinoflagellatesAlexandrium tamarenseandA. ostenfeldiiin co-occurring natural populations from Scottish coastal waters

Development of a Real-Time PCR Assay for Rapid Detection and Quantification ofAlexandrium minutum(a Dinoflagellate)

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