Domoic Acid—A Neurotoxic Amino Acid Produced by the Marine Diatom Nitzschia pungens in Culture

1988 ◽  
Vol 45 (12) ◽  
pp. 2076-2079 ◽  
Author(s):  
D. V. Subba Rao ◽  
M. A. Quilliam ◽  
R. Pocklington
Keyword(s):  
Amino Acid ◽  
Chemical Analysis ◽  
River Water ◽  
Prince Edward Island ◽  
Domoic Acid ◽  
Culture Medium ◽  
Marine Diatom ◽  
Eastern Canada ◽  
Blue Mussels ◽  
Nitzschia Pungens

During late 1987, an outbreak of poisoning resulting from the ingestion of cultivated blue mussels (Mytilus edulis) from a localized area in eastern Canada (Cardigan Bay, Prince Edward Island) was associated with massive blooms of Nitzschia pungens, a widely distributed diatom not previously known to produce toxins; human fatalities resulted. Here we provide proof that the causative agent, domoic acid, is indeed produced by this diatom. Although no domoic acid could be detected (<2 ng∙mL−1) in culture medium (FE) prepared from Cardigan River water, it was found in cultures of Nitzschia pungens grown in this medium at concentrations ranging from 0.03 to 0.8 pg∙cell−1 in various separate cultures harvested for chemical analysis 7–68 d after inoculation.

The effect of salinity on growth and amino acid composition in the marine diatom Nitzschia pungens

1992 ◽  
Vol 70 (11) ◽  
pp. 2198-2201 ◽  
Author(s):  
Anne E. Jackson ◽  
Stephen W. Ayer ◽  
Maurice V. Laycock
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Osmotic Pressure ◽  
Marine Diatom ◽  
Salinity Range ◽  
Optimal Salinity ◽  
Maritime Canada ◽  
Total Amino Acids ◽  
Positive Compound ◽  
Nitzschia Pungens

Nitzschia pungens f. multiseries and N. pungens f. pungens, isolated from two estuaries in Maritime Canada, were grown at various salinities (6–48‰) and their growth rates and free amino acid compositions were determined. The optimal salinity range for growth of f. multiseries was 30–45‰, whereas that of f. pungens was 15–30‰. At higher salinities there was increased production of a ninhydrin-positive compound, which was identified as the amino acid taurine. When f. multiseries was grown at a salinity of 48‰ and rapidly exposed to 15‰, the concentration of taurine decreased markedly (from 61 to 7% of the total amino acids). The evidence indicates that taurine may serve to regulate the osmotic pressure of N. pungens f. multiseries, a role not previously assigned to taurine in a marine diatom. Key words: Nitzschia pungens, salinity, osmotic pressure, amino acids, taurine.

Pennate Diatom Nitzschia pungens as the Primary Source of Domoic Acid, a Toxin in Shellfish from Eastern Prince Edward Island, Canada

1989 ◽  
Vol 46 (7) ◽  
pp. 1203-1215 ◽  
Author(s):  
S. S. Bates ◽  
C J. Bird ◽  
A. S. W. de Freitas ◽  
R. Foxall ◽  
M. Gilgan ◽  
...  
Keyword(s):  
Prince Edward Island ◽  
Domoic Acid ◽  
Food Poisoning ◽  
Primary Source ◽  
Pennate Diatom ◽  
Closely Related Species ◽  
Plankton Bloom ◽  
Amphora Coffeaeformis ◽  
Human Poisoning ◽  
Nitzschia Pungens

An outbreak of food poisoning in Canada during autumn 1987 was traced to cultured blue mussels (Mytilus edulis) from the Cardigan Bay region of eastern Prince Edward Island (P.E.I.). The toxin, identified as domoic acid, had not previously been found in any shellfish and this outbreak represents the first known occurrence of human poisoning by this neurotoxin. A plankton bloom at the time of the outbreak consisted almost entirely of the pennate diatom, Nitzschia pungens f. multiseries, and a positive correlation was found between the number of N. pungens cells and the concentration of domoic acid in the plankton. Nitzschia pungens f. multiseries isolated from Cardigan Bay produced domoic acid in culture at levels (1 to 20 pg∙cell−1) comparable with values estimated for N. pungens in the plankton samples. Isolates of several Cardigan Bay phytoplankton, including the closely related species Nitzschia seriata, failed to produce domoic acid. Other Nitzschia spp. and two Amphora coffeaeformis isolates also failed to produce domoic acid. We conclude that N. pungens was the major source of the domoic acid in toxic mussels in eastern P.E.I. The recurrence, in November 1988, of a monospecific bloom of N. pungens and the presence of domoic acid in plankton and mussels reinforced this conclusion.

Microscopic examinations of toxic marine microalgae

1992 ◽  
Vol 50 (1) ◽  
pp. 830-831
Author(s):  
David O’Neil ◽  
Cynthia Leggiadro ◽  
Gwang Hoon Kim ◽  
Lawrence Fritz
Keyword(s):  
Light Microscopy ◽  
Okadaic Acid ◽  
Pure Culture ◽  
Domoic Acid ◽  
Marine Diatom ◽  
Distinctive Pattern ◽  
Eastern Canada ◽  
Pennate Diatom ◽  
Distinctive Features ◽  
Fish Poison

A number of microalgae have been implicated in toxicity episodes in cultured shellfish in Eastern Canada. Nitzschia pungens f. multiseries and Prorocentrum lima are two organisms that have been shown to produce the toxins associated with poisonous shellfish. The present study examines these organisms by light microscopy (DIC and fluorescence), and SEM.The pennate marine diatom, N. pungens(fig. 2), has been shown to produce a potent neurotoxin, domoic acid, in pure culture. The distinctive features of this pennate diatom are illustrated in Fig. 1. The silica covering (frustule) consists of parallel rows of costa with multiple rows of minute pores (poroids). P. lima (fig. 5) is a dinoflagellate that has been found to produce a toxin known as okadaic acid. This toxin has been associated with ciguatera, a fish poison, and was implicated in a recent toxic shellfish event in Eastern Canada. The cellulosic thecal plates are adorned with regular, distinctive pattern of pores (fig. 4).

Controls on Domoic Acid Production by the Diatom Nitzschia pungens f. multiseries in Culture: Nutrients and Irradïance

1991 ◽  
Vol 48 (7) ◽  
pp. 1136-1144 ◽  
Author(s):  
S. S. Bates ◽  
A. S. W. de Freitas ◽  
J. E. Milley ◽  
R. Pocklington ◽  
M. A. Quilliam ◽  
...  
Keyword(s):  
Cell Division ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Domoic Acid ◽  
Culture Medium ◽  
Dark Period ◽  
Growth Conditions ◽  
Dark Cycle ◽  
Division Rate ◽  
Nitzschia Pungens

Nitzschia pungens f. multiseries (clone NPARL) was grown in nonaxenic batch culture under a range of growth conditions. Domoic acid (DA) was not detected during exponential growth, but production promptly started at a rate of approximately 1 pg DA∙cell−1∙d−1 at the onset of the stationary phase, in this case induced by silicate limitation. Cellular DA reached a maximum of 7 pg∙cell−1; thereafter, DA production continued at the same rate, with cellular levels remaining relatively constant due to concurrent release of DA into the culture medium. DA production ceased in the absence of nitrogen during the stationary phase, but resumed when nitrate was added back to the medium. Low irradiance slowed the division rate and consequently delayed the attainment of the stationary phase, but DA production rates were comparable with the control once stationary phase was reached. Cells during the dark period of a light–dark cycle, or placed into darkness, or in the presence of the photosynthetic inhibitor DCMU promptly ceased DA production. We conclude that at least three conditions are required for DA production by clone NPARL: cessation of cell division, availability of nitrogen during the stationary phase, and the presence of light. Growth in medium f/2 fulfils these requirements.

Depuration of Domoic Acid from Live Blue Mussels (Mytilus edulis)

1992 ◽  
Vol 49 (2) ◽  
pp. 312-318 ◽  
Author(s):  
I. Novaczek ◽  
M. S. Madhyastha ◽  
R. F. Ablett ◽  
A. Donald ◽  
G. Johnson ◽  
...  
Keyword(s):  
Mytilus Edulis ◽  
Prince Edward Island ◽  
Domoic Acid ◽  
Unit Weight ◽  
Concentration Data ◽  
Blue Mussels ◽  
Significant Difference ◽  
Intracellular Compartments ◽  
Effects Of Temperature ◽  
Depuration Rate

Industrial depuration may provide a means of removing domoic acid toxin from blue mussels (Mytilus edulis). Mussels containing up to 50 μg domoic acid∙g−1 were transported from a Prince Edward Island estuary into controlled laboratory conditions to test the effects of temperature, salinity, mussel size, and feeding upon depuration. Fifty percent of toxin was eliminated within 24 h. After 72 h, mussels were either clean or contained, on average, only residual levels of toxin (< 5 μg∙g−1), regardless of conditions. Exponential depuration curves were fitted to the domoic acid concentration data. To evaluate differences in rate of depuration under various conditions, statistical comparisons were made between slopes of the clearance curves. Rates of depuration were faster in small (45–55 mm) than in large mussels (60–70 mm) and more rapid at 11 than at 6 °C. There was no significant difference in depuration rate at 18‰ salinity as opposed to 28‰ or in starved versus fed mussels. Because of their relatively large digestive glands, meats of small mussels contained more toxin per unit weight than meats of large mussels. The bulk of domoic acid appeared to reside in the gut lumen. However, the presence of small amounts of domoic acid in intracellular compartments cannot be ruled out.

Production of Domoic Acid, a Neurotoxic Amino Acid, by an Axenic Culture of the Marine Diatom Nitzschia pungens f. multiseries Hasle

1992 ◽  
Vol 49 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Donald J. Douglas ◽  
Stephen S. Bates
Keyword(s):  
Cell Division ◽  
Stationary Phase ◽  
Domoic Acid ◽  
Stationary Phases ◽  
Axenic Culture ◽  
Marine Diatom ◽  
Epifluorescence Microscopy ◽  
Division Rate ◽  
Growth Production ◽  
Nitzschia Pungens

A microbially contaminated culture of Nitzschia pungens f. multiseries (clone TKA-2) was treated with gentamicin followed by a combination of penicillin and streptomycin. An axenic culture was successfully isolated as evidenced by sterility tests using four different nutrient enrichment media and examination by epifluorescence microscopy. The isolate had a specific division rate (0.65∙d−1) comparable with that reported for nonaxenic cultures. The axenic culture produced domoic acid (DA) during the lag and stationary phases, when cell division rates were low or zero, but not during exponential growth. Production of DA resumed within 1 d after cell division ceased and reached 0.5 pg DA∙cell−1∙d−1 2–3 d after the onset of the stationary phase. A maximum concentration of 2.0 pg DA∙cell−1 was reached after 6 d in stationary phase. Our results provide the first evidence that N. pungens f. multiseries produces DA in the absence of other microorganisms.

Morphology of the Toxin-Producing Diatom Nitzschia pungens Grunow forma multiseries Hasle

1992 ◽  
Vol 49 (2) ◽  
pp. 303-311 ◽  
Author(s):  
Daniel J. MacPhee ◽  
Louis A. Hanic ◽  
Dianne L. Friesen ◽  
David E. Sims
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Cell Motility ◽  
Prince Edward Island ◽  
Domoic Acid ◽  
Light And Electron Microscopy ◽  
Cell Ultrastructure ◽  
Field Samples ◽  
Toxic Blooms ◽  
Nitzschia Pungens

The toxin-producing diatom Nitzschia pungens Grunow forma multiseries Hasle from three toxic blooms in two Prince Edward Island estuaries, spanning 1987–89, was studied using light and electron microscopy. Cell ultrastructure of N. pungens is, in general, similar to that of other species of Nitzschia and other diatoms. Important features include prominent peripheral, polarized nucleoli (numbering one or two) and imperforate poroids, present on inner valves and girdle bands. Cell division is usually synchronous for all cells in a filament with respect to polarity and time. Postdivisional elongation of the filament appears to involve a "slide-by" process whereby sibling cells slide by each other along their opposed valve faces and then stop, becoming fused by their overlapping tips. The raphe is probably involved in this, as well as in filament and cell motility. Observations of particle motion along the cell raphe suggest the existence of a motility apparatus such as microcilia which would facilitate locomotion, intercellular coordination, and the postdivisional slide-by process. No bacteria or other organisms were observed associated with field samples of toxic N. pungens f. multiseries. This supports a view that domoic acid production is autonomous.

Oomycete and chytrid infections of the marine diatom Pseudo-nitzschia pungens (Bacillariophyceae) from Prince Edward Island, Canada

Botany ◽  
2009 ◽  
Vol 87 (11) ◽  
pp. 1096-1105 ◽  
Author(s):  
Louis A. Hanic ◽  
Satoshi Sekimoto ◽  
Stephen S. Bates
Keyword(s):  
Discharge Tube ◽  
Prince Edward Island ◽  
Dense Body ◽  
Morphological Characteristics ◽  
Marine Diatom ◽  
Cell Infection ◽  
Host Cytoplasm ◽  
Single Discharge ◽  
Thickened Base ◽  
Nitzschia Pungens

Two eukaryotic parasites were found infecting the bloom-forming marine diatom Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle in Prince Edward Island, Canada. The most common was an oomycete; the other, seen once, was a chytrid. The structure of the discharged sporangium of both is remarkably similar. The oomycete parasite caused the host cell to lay down several extra girdle bands as the parasite thallus grew and swelled to form a holocarpic, endobiotic, nonwalled multinucleate thallus within the host cytoplasm. At maturity the thallus formed a single discharge tube with a thickened base and a thin papillate apex. Many biflagaellate zoospores were formed that burst out from the discharge tube. Ultrastructural characteristics of the oomycete thallus include mitochondria with tubular cristae and vesicles with dense body inclusions, features common to the oomycetes. The morphological characteristics and biflagellate condition indicate a placement of this form in the genus Ectrogella . However, neither flagellar mastigonemes nor flagella flimmer vesicles were found. The absence of flimmers may indicate a closer phylogenetic relationship to Haptoglossa , an endoparasitic oomycete of nematodes, the zoospores of which lack flagellar mastigonemes. Cell infection frequencies ranged from 0.6%–15.9% during 1992–1995, at the four sampling sites.

Identification of domoic acid, a neuroexcitatory amino acid, in toxic mussels from eastern Prince Edward Island

1989 ◽  
Vol 67 (3) ◽  
pp. 481-490 ◽  
Author(s):  
J. L. C. Wright ◽  
R. K. Boyd ◽  
A. S. W. de Freitas ◽  
M. Falk ◽  
R. A. Foxall ◽  
...  
Keyword(s):  
Amino Acid ◽  
Prince Edward Island ◽  
High Performance ◽  
Domoic Acid ◽  
Analytical Data ◽  
Paper Electrophoresis ◽  
Exchange Chromatography ◽  
Spectroscopic Techniques ◽  
Isolation And Purification ◽  
Shellfish Toxin

The causative agent of toxicity in cultured mussels from a localized area of eastern Prince Edward Island has been identified as domoic acid, a neuroexcitatory amino acid. The toxin was isolated by a number of different bioassay-directed separation techniques including high-performance liquid chromatography, high-voltage paper electrophoresis, and ion-exchange chromatography, and characterized by a number of spectroscopic techniques including ultraviolet, infrared, mass spectrometry, and nuclear magnetic resonance. The isolation and purification methods are described in detail and some new analytical data for domoic acid are reported. Keywords: shellfish toxin, domoic acid, neurotoxin, bioassay-directed analysis.

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