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Ecology

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D. acuta is a planktonic oceanic and neritic species (Dodge 1982; Taylor et al. 1995; Steidinger & Tangen 1996). This is a bloom-forming species; blooms are often associated with shellfish toxicity (Taylor et al. 1995).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Habitat and Locality

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Dinophysis acuta is widely distributed in cold and temperate waters world-wide (Larsen & Moestrup 1992; Steidinger & Tangen 1996).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Morphology and Structure

provided by NMNH Marine Dinoflagellates
Dinophysis acuta is a photosynthetic species with yellow chloroplasts (Dodge 1982; Larsen & Moestrup 1992).
Dimorphic cells, one half resembling D. acuta and the other half resembling D. dens (the proposed gamete form), have occasionally been observed in this species (Reguera et al. 1990; Hansen 1993; Moita & Sampayo 1993). It is highly probable that these cell forms represent a stage in gametogenesis (Hansen 1993).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Nomenclatural Types

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Holotype: Dinophysis acuta Ehrenberg, 1839: 124, 151, plate 4 (fide Schiller, 1933)
Type Locality: Mediterranean Sea: Gulf of Lion, France
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Remarks

provided by NMNH Marine Dinoflagellates
Many authors consider Phalacroma to be synonymous with Dinophysis (Steidinger & Tangen 1996).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Reproduction

provided by NMNH Marine Dinoflagellates
D. acuta reproduces asexually by binary fission. Hansen (1993) speculates that sexual reproduction, with sexual dimorphism, is part of the life cycle for this species.
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bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Species Comparison

provided by NMNH Marine Dinoflagellates
D. acuta is very similar to D. norvegica in their general shape, and thus can easily be misidentified. D. acuta can be differentiated by its larger size and different shape: D. norvegica is widest in the middle region of the cell, whereas D. acuta is widest below the mid-section. Moreover, D. acuta has a longer left sulcal list relative to its cell length (Balech 1976; Dodge 1982; Larsen & Moestrup 1992; Taylor et al. 1995; Steidinger & Tangen 1996). D. acuta also strongly resembles a warm-water species, D. schroederi Pavillard, 1909 (Schiller 1933; Balech 1976; Burns & Mitchell 1982).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Species Overview

provided by NMNH Marine Dinoflagellates
Dinophysis acuta is an armoured, marine, planktonic dinoflagellate species. It is a toxic species associated with DSP events and is commonly found in cold and temperate neritic waters.
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Taxonomic Description

provided by NMNH Marine Dinoflagellates
Species in this genus are laterally compressed with a small, cap-like epitheca and a much larger hypotheca (dorso-ventral depth of epitheca is 1/2 to 2/3 of hypotheca). The shape of the cell in lateral view is the most important criterion used for identification (Taylor et al. 1995).
Cells of Dinophysis acuta are large and robust, and are among the largest species in the genus Dinophysis (Fig. 1). Cells are oblong with a slightly pointed or rounded posterior end (Figs. 1-4). The left sulcal list (LSL) extends beyond the midpoint of the cell (about 2/3 of cell length) ending at or above the widest portion of the cell (Fig. 3) (Balech 1976; Dodge 1982; Larsen & Moestrup 1992; Taylor et al. 1995; Steidinger & Tangen 1996).
The thick thecal plates of the hypotheca are coarsely areolated, each areola with a central pore (Figs. 1, 2, 4). The areolation becomes very faint or disappears near the edge of the plates. Cell size ranges: 54-94 µm in length and 43-60 µm in dorso-ventral width (widest below the middle) (Fig. 3)(Balech 1976; Dodge 1982; Larsen & Moestrup 1992; Taylor et al. 1995; Steidinger & Tangen 1996).
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Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Thecal Plate Description

provided by NMNH Marine Dinoflagellates
The small epitheca is made up of four plates. It is low, flat or weakly convex, and is not visible in lateral view (Balech 1976; Larsen & Moestrup 1992; Taylor et al. 1995).
The cingulum is made up of four unequal plates, all with pores. Well developed cingular lists are present: an anterior cingular list (ACL), and a posterior cingular list (PCL). They are generally smooth and rarely ornamented (Fig. 3). The high ACL obscures the low epitheca (Balech 1976; Dodge 1982; Larsen & Moestrup 1992).
The sulcus is comprised of several irregularly shaped plates. The flagellar pore is housed in the sulcal area. The left sulcal list (LSL), supported by three ribs that radiate outward, is rather broad with a convex ventral margin. It is wider posteriorly and slightly areolated. The second sulcal rib is closer to the first than to the third. The third rib is the longest (Figs. 1-4) (Balech 1976; Dodge 1982; Taylor et al. 1995).
The hypotheca, with four large plates, comprises the majority of the cell. The anterior 2/3 of the hypotheca has convex margins, while the posterior third of the hypotheca forms a broad asymmetrical triangle with a straight dorsal edge and occasionally a slightly concave ventral edge (Figs. 1-4). The tapered and roughly pointed antapex is directed slightly ventrally (Figs. 1-4) (Balech 1976; Dodge 1982; Taylor et al. 1995). Balech (1976: figs. 2H, 2I) depicts two specimens with two to three small knob-like spines on the posterior end.
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cc-publicdomain
bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Toxicity

provided by NMNH Marine Dinoflagellates
D. acuta is a toxic species that produces okadaic acid (OA), as well as Dinophysistoxin-1 (DTX1) (Lee et al. 1989; Yasumoto 1990). D. acuta has been associated with DSP outbreaks in Chile (Larsen & Moestrup 1992), Portugal (Alvito et al. 1990; Sampayo et al. 1990), Scandinavia (Dahl & Yndestad 1985; Krogh et al. 1985; Underdahl et al. 1985; Edler & Hageltorn 1990), and the USA (Freudenthal & Jijina 1985).
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bibliographic citation
Faust, Maria A. and Rose A. Gulledge. Identifying Harmful Marine Dinoflagellates. Smithsonian Contributions from the United States National Herbarium, volume 42: 1-144 (including 48 plates, 1 figure and 1 table).

Dinophysis acuta

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Dinophysis acuta is a species of flagellated planktons belonging to the genus Dinophysis. It is one of the few unusual photosynthetic protists that acquire plastids from algae by endosymbiosis. By forming massive blooms, particularly in late summer and spring, it causes red tides. It produces toxic substances and the red tides cause widespread infection of seafood, particularly crabs and mussels. When infected animals are consumed, severe diarrhoea occurs. The clinical symptom is called diarrhetic shellfish poisoning.[1] The main chemical toxins were identified in 2006 as okadaic acid and pectenotoxins.[2][3][4] They can produce non-fatal or fatal amounts of toxins in their predators, which can become toxic to humans.

Description

Dinophysis acuta is a marine unicellular protist, and is the largest among Dinophysis. It is an armoured species with a distinct body covering called theca or test. The body is laterally compressed with a small, cap-like epitheca and a much larger hypotheca. It has the double collars (known as cingulum) around the top of the cell, and a further wing (known as the sulcus) running vertically down the cell. It is oblong in shape with almost entirely rounded posterior end, but the tip of the end is slightly pointed. The size ranges from 54 to 94 µm in length and 43 to 60 µm in dorso-ventral width, with the widest region below the middle. The small epitheca is composed of four plates. It is low, flat or weakly convex, and is invisible in lateral view, which is a good identifying feature. The sulcus consists of several irregularly-shaped plates, and it contains the flagellar pore. The hypotheca has four large plates that constitute the majority of the cell. The anterior two-thirds of the hypotheca has convex margins, while the posterior third forms a broad asymmetrical triangle with a straight dorsal edge, and occasionally a slightly concave ventral edge. Reproduction is by simple binary fission. The most unusual cellular structure is the presence of numerous reddish-yellow chloroplasts, which are derived from its prey, which in turn had acquired from algae.[5][6][7]

Diarrhetic shellfish poisoning

The first cases of diarrhetic shellfish poisoning (DSP) due to D. acuta were recorded in 1972 in Peru, but were reported to the scientific community only in 1991.[8] It is a mildest form of seafood poisoning, indicated by severe diarrhoea.[1] The first toxins isolated from the species were pectenotoxins (PTX-2 and PTX-11) in 2003 from specimens collected from the west coast of South Island, New Zealand,[9] and PTX-12 independently at Skjer, Sognefjorden in Norway.[10] In 2004, the presence of okadaic acid esters was reported.[11] Further identification and the importance of these compounds as causal factors of DSP were discovered in 2006.[2][3][4]

References

  1. ^ a b Arieti, David; Nieva, Jakob; Swiller, Randolf (2011). Prognosis Disaster: The Environment, Climate Change, Human Influences, Vectors, Disease and the Possible End of Humanity?. Author House. p. 404. ISBN 9781456731496.
  2. ^ a b Miles, Christopher O.; Wilkins, Alistair L.; Hawkes, Allan D.; Jensen, Dwayne J.; Cooney, Janine M.; Larsen, Kristofer; Petersen, Dirk; Rise, Frode; Beuzenberg, Veronica; Lincoln MacKenzie, A. (2006). "Isolation and identification of a cis-C8-diol-ester of okadaic acid from Dinophysis acuta in New Zealand". Toxicon. 48 (2): 195–203. doi:10.1016/j.toxicon.2006.04.018. PMID 16784765.
  3. ^ a b Miles, Christopher Owen; Wilkins, Alistair L.; Hawkes, Allan D.; Jensen, Dwayne J.; Selwood, Andrew I.; Beuzenberg, Veronica; Lincoln MacKenzie, A.; Cooney, Janine M.; Holland, Patrick T. (Aug 2006). "Isolation and identification of pectenotoxins-13 and -14 from Dinophysis acuta in New Zealand". Toxicon. 48 (2): 152–159. doi:10.1016/j.toxicon.2006.04.005. PMID 16828828.
  4. ^ a b Suzuki, Toshiyuki; Walter, John A.; LeBlanc, Patricia; MacKinnon, Shawna; Miles, Christopher O.; Wilkins, Alistair L.; Munday, Rex; Beuzenberg, Veronica; MacKenzie, A. Lincoln; Jensen, Dwayne J.; Cooney, Janine M.; Quilliam, Michael A. (2006). "Identification of pectenotoxin-11 as 34S-hydroxypectenotoxin-2, a new pectenotoxin analogue in the toxic dinoflagellate Dinophysis acuta from New Zealand". Chemical Research in Toxicology. 19 (2): 310–318. doi:10.1021/tx050240y. PMID 16485908.
  5. ^ "Identifying harmful marine dinoflagellates". Department of Botany, Smithsonian Institution. Retrieved 25 August 2014.
  6. ^ Lassus, P.; Seguel, M.; Truquet, P. (1998). "Morphological study of atypical Dinophysis acuta Ehrenberg from Chilean coastal waters by a digital pattern-recognition system". Botanica Marina. 41 (1–6): 435–441. doi:10.1515/botm.1998.41.1-6.435. S2CID 85769394.
  7. ^ Burns, D.A.; Mitchell, J.S. (1982). "Dinoflagellates of the genus Dinophysis Ehrenberg from New Zealand coastal waters". New Zealand Journal of Marine and Freshwater Research. 16 (3–4): 289–298. doi:10.1080/00288330.1982.9515972.
  8. ^ Lembeye, G; Yasumoto, T; Zhao, J; Fernandez, R (1993). "DSP outbreak in Chilean Fiords". In Smayda, Theodore J; Shimizu, Yuzuru (eds.). Toxic phytoplankton blooms in the sea. Amsterdam: Elsevier Science Publishers. pp. 525–529. ISBN 9780444897190.
  9. ^ Suzuki, T; Beuzenberg, V; Mackenzie, L; Quilliam, MA (2003). "Liquid chromatography-mass spectrometry of spiroketal stereoisomers of pectenotoxins and the analysis of novel pectenotoxin isomers in the toxic dinoflagellate Dinophysis acuta from New Zealand". Journal of Chromatography A. 992 (1–2): 141–50. doi:10.1016/s0021-9673(03)00324-8. PMID 12735470.
  10. ^ Miles, Christopher O.; Wilkins, Alistair L.; Samdal, Ingunn A.; Sandvik, Morten; Petersen, Dirk; Quilliam, Michael A.; Naustvoll, Lars J.; Rundberget, Thomas; Torgersen, Trine; Hovgaard, Peter; Jensen, Dwayne J.; Cooney, Janine M. (2003). "A novel pectenotoxin, PTX-12, in Dinophysis spp. and shellfish from Norway". Chemical Research in Toxicology. 17 (11): 1423–1433. doi:10.1021/tx049870a. PMID 15540940.
  11. ^ Suzuki, T.; Beuzenberg, V.; Mackenzie, L.; Quilliam, M. A. (2004). "Discovery of okadaic acid esters in the toxic dinoflagellate Dinophysis acuta from New Zealand using liquid chromatography/tandem mass spectrometry". Rapid Communications in Mass Spectrometry. 18 (10): 1131–1138. Bibcode:2004RCMS...18.1131S. doi:10.1002/rcm.1455. PMID 15150838.

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Dinophysis acuta: Brief Summary

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Dinophysis acuta is a species of flagellated planktons belonging to the genus Dinophysis. It is one of the few unusual photosynthetic protists that acquire plastids from algae by endosymbiosis. By forming massive blooms, particularly in late summer and spring, it causes red tides. It produces toxic substances and the red tides cause widespread infection of seafood, particularly crabs and mussels. When infected animals are consumed, severe diarrhoea occurs. The clinical symptom is called diarrhetic shellfish poisoning. The main chemical toxins were identified in 2006 as okadaic acid and pectenotoxins. They can produce non-fatal or fatal amounts of toxins in their predators, which can become toxic to humans.

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