A STUDY OF THE PSEUDO‐NITZSCHIA PSEUDODELICATISSIMA/CUSPIDATA COMPLEX (BACILLARIOPHYCEAE): WHAT IS P. PSEUDODELICATISSIMA? 1

Lundholm, Nina; Moestrup, Øjvind; Hasle, Gunnar; Hoef‐Emden, Kerstin

doi:10.1046/j.1529-8817.2003.02031.x

Cited by 242 publications

(387 citation statements)

References 44 publications

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“…And recent data obligingly confirm that, indeed, speciation is not always accompanied by significant morphological change: good examples of semicryptic and cryptic speciation are now available (e.g. Mann 1999b; Lundholm et al 2003;Montresor et al 2003;Behnke et al 2004;Sarno et al 2005). Data from 'model systems', such as Sellaphora pupula (Kützing) Mereschkowsky (Mann 1999b;Mann et al 1999;Behnke et al 2004), the Diploneis smithii-fusca complex (Droop 1994;Droop et al 2000), Pseudo-nitzschia (e.g.…”

Section: Speciation and Microevolutionmentioning

confidence: 95%

Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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Molecular sequence analyses have yielded many important insights into diatom evolution, but there have been few attempts to relate these to the extensive fossil record of diatoms, probably because of unfamiliarity with the data available, which are scattered widely through the geological literature. We review the main features of molecular phylogenies and concentrate on the correspondence between these and the fossil record; we also review the evolution of major morphological, cytological and life cycle characteristics, and possible diatom origins. The first physical remains of diatoms are from the Jurassic, and well-preserved, diverse floras are available from the Lower Cretaceous. Though these are unequivocally identifiable as centric diatoms, none except a possible Stephanopyxis can be unequivocally linked to lineages of extant diatoms, although it is almost certain that members of the Coscinodiscophyceae (radial centrics) and Mediophyceae (polar centrics) were present; some display curious morphological features that hint at an unorthodox cell division mechanism and life cycle. It seems most likely that the earliest diatoms were marine, but recently discovered fossil deposits hint that episodes of terrestrial colonization may have occurred in the Mesozoic, though the main invasion of freshwaters appears to have been delayed until the Cenozoic. By the Upper Cretaceous, many lineages are present that can be convincingly related to extant diatom taxa. Pennate diatoms appear in the late Cretaceous and raphid diatoms in the Palaeocene, though molecular phylogenies imply that raphid diatoms did in fact evolve considerably earlier. Recent evidence shows that diatoms are substantially underclassified at the species level, with many semicryptic or cryptic species to be recognized; however, there is little prospect of being able to discriminate between such taxa in fossil material.

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Section: Speciation and Microevolutionmentioning

confidence: 95%

Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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“…Bands and girdle details could not be observed. Given that neither transmission electron observations nor molecular analysis were carried out during this study, these specimens could only be assigned as part of the Pseudo-nitzschia pseudodelicatissima (Hasle) Hasle species complex sensu Lundholm et al (2003).…”

Section: Pseudo-nitzschia Diversitymentioning

confidence: 99%

Species occurrence of the potentially toxigenic diatom genus Pseudo-nitzschia and the associated neurotoxin domoic acid in the Argentine Sea

et al. 2017

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Keywords:Amnesic shellfish poisoning South-western Atlantic Pseudo-nitzschia diversity P. australis P. brasiliana Domoic acid A B S T R A C TThe marine diatom genus Pseudo-nitzschia, the major known producer of the neurotoxin domoic acid (DA) responsible for the amnesic shellfish poisoning (ASP) syndrome in humans and marine mammals, is globally distributed. The genus presents high species richness in the Argentine Sea and DA has been frequently detected in the last few years in plankton and shellfish samples, but the species identity of the producers remains unclear. In the present work, the distribution and abundance of Pseudo-nitzschia species and DA were determined from samples collected on two oceanographic cruises carried out through the Argentine Sea ($39-47 S) during summer and spring 2013. Phytoplankton composition was analysed by light and electron microscopy while DA was determined by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The genus Pseudo-nitzschia was recorded in 71 and 86% of samples collected in summer and spring, respectively, whereas DA was detected in only 42 and 21% of samples, respectively. Microscopic analyses revealed at least five potentially toxic species (P. australis, P. brasiliana, P. fraudulenta, P. pungens, P. turgidula), plus putatively non-toxigenic P. dolorosa, P. lineola, P. turgiduloides and unidentified specimens of the P. pseudodelicatissima complex. The species P. australis showed the highest correlation with DA occurrence (r = 0.55; p < 0.05), suggesting its importance as a major DA producer in the Argentine Sea. In the northern area and during summer, DA was associated with the presence of P. brasiliana, a species recorded for the first time in the Argentine Sea. By contrast, high concentrations of P. fraudulenta, P. pungens and P. turgidula did not correspond with DA occurrence. This study represents the first successful attempt to link toxigenicity with Pseudo-nitzschia diversity and cell abundance in field plankton populations in the south-western Atlantic.

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“…The ITS1, 5.8S and ITS2 of the nuclear-encoded rDNA (designated ITS) and the D1-D3 regions of the LSU rDNA (designated LSU) were amplified using primers listed in Lundholm et al (2002Lundholm et al ( , 2003. The conditions were: one initial denaturation at 94 C for 2 min, followed by 30-36 cycles each comprising 94 C for 30 s, 60 C for 25 s, 72 C for 25 s, and 72 C for 3 min.…”

Section: Dna Extraction Amplification and Sequencingmentioning

confidence: 99%

“…PCRproducts were purified using QIAquick PCR Purification Kit (Qiagen, Germany). Thirty to 40 ng PCR-product were used in each 20-ml sequencing reaction with the sequencing primers used in Lundholm et al (2002Lundholm et al ( , 2003. Nucleotide sequences were determined using the Dye Terminator Cycle Sequencing Ready Reaction Kit (Perkin Elmer, California) and sequencing was done using an ABI Prism 377 DNA sequencer (Perkin Elmer).…”

Section: Dna Extraction Amplification and Sequencingmentioning

confidence: 99%

Morphological and phylogenetic comparisons ofNeodenticula seminae(Bacillariophyta) populations between the subarctic Pacific and the Gulf of St. Lawrence

Poulin

Lundholm²,

Bérard-Therriault

et al. 2010

European Journal of Phycology

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Neodenticula seminae is a very important member of modern diatom assemblages in the Bering Sea and at middle to high latitudes of the North Pacific. In the North Atlantic, this species was considered extinct until it was recorded in high abundance in the 2001 spring phytoplankton bloom of the Gulf of St. Lawrence, Eastern Canada. Here, we discuss some of the most distinctive features of its morphology, including variation in some characters between the subarctic Pacific and the Gulf of St. Lawrence specimens. Most importantly, we observed that the deck and basal ridges, and the solid-walled costae (formerly known as primary pseudosepta) characteristic of N. seminae were present in the subarctic Pacific material, but were absent or vestigial in the Gulf of St. Lawrence material and in cultures from both regions. This morphological variation was most likely due to differences in physico-chemical water properties between the subarctic Pacific and the Gulf of St. Lawrence. Phylogenetic analyses of the internal transcribed spacer regions of the nuclear ribosomal DNA showed that the strains of N. seminae collected in the Gulf of St. Lawrence and the subarctic Pacific clustered in two sister clades, but differed from each other only slightly more than the variation among the subarctic Pacific strains. These results confirmed the reappearance of N. seminae in the NW Atlantic after an absence of $0.8 Ma. In addition, the phylogenetic analyses based on the large subunit of the nuclear ribosomal DNA positioned N. seminae firmly within the Bacillariaceae (i.e. diatoms with a fibulate raphe system) and proved a close relationship to species of Fragilariopsis.

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A STUDY OF THE PSEUDO‐NITZSCHIA PSEUDODELICATISSIMA/CUSPIDATA COMPLEX (BACILLARIOPHYCEAE): WHAT IS P. PSEUDODELICATISSIMA? ¹

Cited by 242 publications

References 44 publications

Evolution of the diatoms: insights from fossil, biological and molecular data

Evolution of the diatoms: insights from fossil, biological and molecular data

Species occurrence of the potentially toxigenic diatom genus Pseudo-nitzschia and the associated neurotoxin domoic acid in the Argentine Sea

Morphological and phylogenetic comparisons ofNeodenticula seminae(Bacillariophyta) populations between the subarctic Pacific and the Gulf of St. Lawrence

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