Morphogenetic diversity and biotoxin composition of Alexandrium (Dinophyceae) in Irish coastal waters

Touzet, Nicolas; Franco, José M.; Raine, Robin

doi:10.1016/j.hal.2008.04.001

Cited by 105 publications

(114 citation statements)

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“…Strains from Danish waters and a strain isolated from the south coast in England have also been observed to produce low amounts of both groups of toxins (Hansen et al, 1992;Percy, 2006). In contrast, Touzet et al (2008) report on spirolide production by isolates from Irish waters, but did not find evidence for the production of PSP toxins. Interestingly, PSP toxin production has been detected in strains isolated from the Å land Archipelago on the south-west coast of Finland, however no spirolide production was observed (Kremp et al, 2009 detected in A. ostenfeldii exponentially growing cells in batch culture compared with concentrations produced by A. tamarense (Table 2).…”

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confidence: 83%

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Distribution, diversity and toxin composition of the genusAlexandrium(Dinophyceae) in Scottish waters

Brown

Bresnan

Graham

et al. 2010

European Journal of Phycology

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Alexandrium is detected throughout Scottish coastal waters on a near annual basis, and corresponding paralytic shellfish poisoning (PSP) toxins are found in Scottish shellfish. Previous studies at selected Scottish sites have shown diversity within the genus Alexandrium. In order to examine the distribution, diversity and toxicity of Alexandrium populations around the Scottish coast, historic cyst and cell data were compiled and cultures established from sediment and water samples. Historic data showed high cell densities of Alexandrium in Shetland, Orkney, the Western Isles and mainland east coast. Low abundances of Alexandrium cysts were observed along the west coast. Four species of Alexandrium (A. tamarense, A. ostenfeldii, A. minutum and A. tamutum) were established in laboratory culture and identified using morphological criteria. Sequencing of LSU rDNA from isolates of A. ostenfeldii, A. minutum and A. tamutum confirmed their identification and showed them to be similar to other European strains. Alexandrium tamarense, identified by morphological criteria, was observed to have a widespread distribution around the coast. Both toxin-and non toxin-producing strains of this species were isolated, suggesting the presence of A. tamarense Groups I and III. Alexandrium ostenfeldii was isolated from the east coast and Shetland Isles and was observed to produce both spirolide and PSP toxins. Alexandrium tamutum was identified from cultures isolated from Shetland and Orkney, the most northerly observation of this species to date. PSP toxins were not detected in isolates of A. minutum from the east coast and Orkney or of A. tamutum under the culture conditions used. This study has highlighted the diversity of Alexandrium in Scottish waters and reveals the requirement for temporal and regional studies on a species level in order to understand the variation in cell densities and PSP toxicity that is observed on an annual and decadal scale.

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confidence: 83%

“…Toxin analogues were dominated by C2 and NEO and to a lesser extent, C1 and STX. Toxic Scottish and Irish A. tamarense isolates have shown similar toxin profiles, with high contributions of C2, NEO and STX (Touzet et al, 2008;Collins et al, 2009). Cultures for PSP toxin analysis were sampled once they had achieved a high cell density.…”

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confidence: 99%

Distribution, diversity and toxin composition of the genusAlexandrium(Dinophyceae) in Scottish waters

Brown

Bresnan

Graham

et al. 2010

European Journal of Phycology

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“…It has been reported that a strain of A. affine can produce low levels of STX (Nguyen Ngoc, 2004), while other studies have found that strains do not produce STXs (Hallegraeff et al, 1991;Band-Schmidt et al, 2003;Stüken et al, 2011;Wang et al, 2006). A strain of Alexandrium andersoni (CCMP2222) was reported to produce low levels of STXs (Ciminiello et al, 2000;Frangopulos et al, 2004), while other studies based on CCMP2222 and other strains of A. andersoni have not detected STXs (Sampedro et al, 2013;Stüken et al, 2011;Orr et al, 2011;Touzet et al, 2008). It is possible that sxtA related genes are no longer expressed in CCMP2222, or that early reports of STX production were in error.…”

Section: Presence Of Sxta Domains A1 and A4 And Sxtgmentioning

confidence: 97%

Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates

Murray

Diwan

Orr

et al. 2015

Molecular Phylogenetics and Evolution

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a b s t r a c tA group of marine dinoflagellates (Alveolata, Eukaryota), consisting of $10 species of the genus Alexandrium, Gymnodinium catenatum and Pyrodinium bahamense, produce the toxin saxitoxin and its analogues (STX), which can accumulate in shellfish, leading to ecosystem and human health impacts. The genes, sxt, putatively involved in STX biosynthesis, have recently been identified, however, the evolution of these genes within dinoflagellates is not clear. There are two reasons for this: uncertainty over the phylogeny of dinoflagellates; and that the sxt genes of many species of Alexandrium and other dinoflagellate genera are not known. Here, we determined the phylogeny of STX-producing and other dinoflagellates based on a concatenated eight-gene alignment. We determined the presence, diversity and phylogeny of sxtA, domains A1 and A4 and sxtG in 52 strains of Alexandrium, and a further 43 species of dinoflagellates and thirteen other alveolates. We confirmed the presence and high sequence conservation of sxtA, domain A4, in 40 strains (35 Alexandrium, 1 Pyrodinium, 4 Gymnodinium) of 8 species of STX-producing dinoflagellates, and absence from non-producing species. We found three paralogs of sxtA, domain A1, and a widespread distribution of sxtA1 in non-STX producing dinoflagellates, indicating duplication events in the evolution of this gene. One paralog, clade 2, of sxtA1 may be particularly related to STX biosynthesis. Similarly, sxtG appears to be generally restricted to STX-producing species, while three amidinotransferase gene paralogs were found in dinoflagellates. We investigated the role of positive (diversifying) selection following duplication in sxtA1 and sxtG, and found negative selection in clades of sxtG and sxtA1, clade 2, suggesting they were functionally constrained. Significant episodic diversifying selection was found in some strains in clade 3 of sxtA1, a clade that may not be involved in STX biosynthesis, indicating pressure for diversification of function.

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“…The toxin content found in this study of 1.29 ± 0.58 pg GTX2, 3 cell -1 is comparable with the toxicity of this species in culture of 1.6 -2.6 pg STX equivalent cell -1 . A field study by Touzet et al (2008) described the detection of low amounts of sulfocarbamate groups such as C-toxins in Cork Harbour. They suggested that these were a chemotype of A. minutum, and is consistent with the present study which detected C1, 2 in stations S1a, S7a and S7b.…”

Section: Discussionmentioning

confidence: 99%

An evaluation of the applicability of microarrays for monitoring toxic algae in Irish coastal waters

McCoy

Touzet

Fleming

et al. 2012

Environ Sci Pollut Res

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Morphogenetic diversity and biotoxin composition of Alexandrium (Dinophyceae) in Irish coastal waters

Cited by 105 publications

References 68 publications

Distribution, diversity and toxin composition of the genusAlexandrium(Dinophyceae) in Scottish waters

Distribution, diversity and toxin composition of the genusAlexandrium(Dinophyceae) in Scottish waters

Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates

An evaluation of the applicability of microarrays for monitoring toxic algae in Irish coastal waters

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