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.

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.

Effects of Ammonium and Nitrate on Growth and Domoic Acid Production by Nitzschia pungens in Batch Culture

1993 ◽  
Vol 50 (6) ◽  
pp. 1248-1254 ◽  
Author(s):  
Stephen S. Bates ◽  
Jean Worms ◽  
John C. Smith
Keyword(s):  
Stationary Phase ◽  
Batch Culture ◽  
Domoic Acid ◽  
Skeletonema Costatum ◽  
Cell Yield ◽  
Ammonia Toxicity ◽  
Lag Phase ◽  
Enhanced Production ◽  
Nitrogen Concentrations ◽  
Nitzschia Pungens

Four clones of Nitzschia pungens f. multiseries (toxin-producing form) and two of N. pungens f. pungens (nontoxic) were grown in batch culture at initial nitrogen concentrations of 55, 110, 220, 440, and 880 μM in the form of either nitrate or ammonium. As expected, only N. pungens f. multiseries clones produced the neurotoxin, domoic acid (DA). Ammonium at 880 μM prevented the growth of all N. pungens clones but not of Skeletonema costatum, although division rate was reduced. At 440 μM, ammonium lowered the cell yield obtained during the stationary phase, inhibited photosynthesis, and caused a lag phase during which DA was produced (by f. multiseries). At 220 and 440 μM ammonium, in contrast with the same concentrations of nitrate, stationary phase cellular DA production was enhanced by two- to fourfold. At 110 and 55 μM nitrogen, cell yield and DA production were equivalent for nitrate and ammonium but less DA was produced relative to the higher nitrogen concentrations, possibly due to nitrogen depletion. Enhanced production of DA at elevated ammonium concentrations may be a response to ammonia toxicity. This could be a useful tool for studying mechanisms of DA production and for maximizing the yield of this valuable toxin in large-scale cultures.

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.

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.

scholarly journals Sexual reproduction and genetic polymorphism within the cosmopolitan marine diatom Pseudo-nitzschia pungens

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jin Ho Kim ◽  
Penelope Ajani ◽  
Shauna A. Murray ◽  
Joo-Hwan Kim ◽  
Hong Chang Lim ◽  
...  
Keyword(s):  
Genetic Polymorphism ◽  
Sexual Reproduction ◽  
Marine Diatom ◽  
Nitzschia Pungens

Carboxylated cyclofructan 6 as a hydrolytically stable high efficiency stationary phase for hydrophilic interaction liquid chromatography and mixed mode separations

2016 ◽  
Vol 8 (31) ◽  
pp. 6038-6045 ◽  
Author(s):  
Yadi Wang ◽  
M. Farooq Wahab ◽  
Zachary S. Breitbach ◽  
Daniel W. Armstrong
Keyword(s):  
Liquid Chromatography ◽  
Benzoic Acid ◽  
Stationary Phase ◽  
Mixed Mode ◽  
High Efficiency ◽  
Stationary Phases ◽  
Hydrophilic Interaction Liquid Chromatography ◽  
Hydrophilic Interaction

Stationary phases composed of native cyclofructan 6 (CF6) and benzoic acid modified CF6 were synthesized and evaluated for hydrophilic interaction liquid chromatography (HILIC).

Sign in / Sign up

Export Citation Format

Share Document