Photosynthesis and growth of Nitzschia pungens f. multiseries Hasle, a neurotoxin producing diatom

Pan, Youlian; Rao, V. Seshagiri; Warnock, Roderick E.

doi:10.1016/0022-0981(91)90076-9

Cited by 21 publications

(24 citation statements)

References 25 publications

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“…In Expt I, although there was sufficient silicate for further growth of the population, ~t never reached more than 1 05 X 10' cells I-', which was comparable to our earlier data from batch culture experiments (Pan et al 1991(Pan et al , 1996. Light was not limiting because the population grew well at much lower light intensities (Pan et al 1991).…”

Section: Discussionsupporting

confidence: 86%

“…Light was not limiting because the population grew well at much lower light intensities (Pan et al 1991). Other nutrients such as nitrogen, phosphorus and vitamins were in excess.…”

Section: Discussionmentioning

confidence: 99%

“…In batch culture, population growth rate changes during the course of the culture cycle, as do the physiological stages (Pan et al 1991). To understand growth rate related physiology, continuous culture study is most suitable since growth rate can be controlled by adjustment of the dilution rate of a steady state.…”

Section: Introductionmentioning

confidence: 99%

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Effects of silicate limitation on production of domoic acid, a neurotoxin, by the diatom Pseudo-nitzschia multiseries. II. Continuous culture studies

Pan¹,

Rao²,

Mann³

et al. 1996

Mar. Ecol. Prog. Ser.

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Production of domoic acid (DA) by Pseudo-nitzschia multiseries (Hasle) was studied using continuous cultures with growth rdtcs ranging from 0 06 to 0.67 d-' At steady states, DA concentrations were 1.65 to 553.20 pg 1-' and production rates were 0 007 to 1.354 pg DA cell-' d-' Both were negatively correlated with rates of growth and silicate uptake. DA production was studled further by stopping the addition of fresh medium, thus producing batch mode experiments, in some of which silicate was allowed to decline, while in another silicate was increased to 85 pM. In those where silicate declined, DA production increased by a factor of 3. The maximum production rate attained was 3.17 pg DA cell-' d-' and the highest DA concentration in the culture was 768.5 1. 19 DA I-'. of which 664 pg 1. ' was in the cells (1 1.9 pg DA cell-'). In the experiment where silicate was enriched. DA production was suspended soon after the enrichment, but resumed when silicate in the medium became low. The results suggested differences in kinetics of DA production and growth under different supply rates of slhcate. There appear to be 2 types of conditions associated with DA production. When dissolved silicate is moderately low and there is a decline in overall physiological activity, intnnsic factors probably trigger the formation of a moderate amount of DA When dissolved silicate IS severely limiting, the extrinsic stress leads to considerably enhanced production of DA. 1989). During these blooms, silicate concentration in the sea water was low (<2 PM; Subba Rao et al. 1988), but the bloom population survived and produced the neurotoxin domoic acid.In batch culture, the production of domoic acid (DA) by Pseudo-nitzschia nlultiseries generally occurs in the stationary phase when cell division has stopped (Subba Rao et al. 1990, Bates et al. 1991 or when growth of the culture populations decline due to silicon limitation (Pan 1994). Pan et al. (1996 -this issue) proposed that DA product~on can be divided into 2 stages: the first coincides with the late exponential phase when growth proceeds slowly, and the second occurs when silicate in the medium is depleted and the culture is in the stationary phase. The rates of DA production during the second stage (13.67 to 30.20 fg DA cell-' d-l) were an order of magnitude higher than those during the first stage (0.97 to 4.98 fg DA cell-' d-l). This implies that (1) toxin production is not necessarily associated with complete cessation of cell division, and (2) this diatom produces more DA when cells are under severe silicate stress. 0

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Section: Discussionsupporting

confidence: 86%

“…Light was not limiting because the population grew well at much lower light intensities (Pan et al 1991). Other nutrients such as nitrogen, phosphorus and vitamins were in excess.…”

Section: Discussionmentioning

confidence: 99%

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Effects of silicate limitation on production of domoic acid, a neurotoxin, by the diatom Pseudo-nitzschia multiseries. II. Continuous culture studies

Pan¹,

Rao²,

Mann³

et al. 1996

Mar. Ecol. Prog. Ser.

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“…Potential toxicity of each culture was tested in f/2* medium with 53 μM Si (to induce Si limitation during stationary phase of growth; Bates et al 1991, Pan et al 1991) with bubbling at an irradiance approximating 150 μmol photons m -2 sec -1 and a 14:10 L:D cycle in 15°C (Bates 1998). In vivo fluorescence of a subsample was measured at the same time daily to monitor growth phase and timing of toxin sample collection.…”

Section: Toxin Content Of Culturesmentioning

confidence: 99%

Intra- and interspecies differences in growth and toxicity of Pseudo-nitzschia while using different nitrogen sources

2009

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Clonal cultures of plankton are widely used in laboratory experiments and have contributed greatly to knowledge of microbial systems. However, many physiological characteristics vary drastically between strains of the same species, calling into question our ability to make ecologically relevant inferences about populations based on studying one or a few strains. This study included nineteen non-axenic strains of three species of the diatom Pseudo-nitzschia isolated primarily from the mid-Atlantic coastal region of the United States.Toxin (domoic acid) production and growth rates were measured in cultures using different nitrogen sources (NH 4 + , NO 3 ⎯ and urea) and growth irradiances. The strains exhibited broad differences in growth rate and toxin content even between strains isolated from the same water sample. The influence of bacteria on toxin production was not investigated. Both P. multiseries clones produced toxin, yet preferentially used different nitrogen sources. Only two out of nine P. calliantha and two out of five P. fraudulenta isolates were toxic and domoic acid content varied by orders of magnitude. All three species had variable intraspecies growth rates on each nitrogen source, but P. fraudulenta strains had the broadest range. Light-limited growth rate and maximum growth rate in P. fraudulenta and P. multiseries varied with species. These findings show the importance of defining intra-and interspecies variability in ecophysiology and toxicity.Ecologically relevant functional diversity in the form of ecotypes or cryptic species appears to be present in the genus Pseudo-nitzschia.

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“…The ASP problem has now been observed on both the Atlantic and Pacific coasts of North America (Fritz et al 1992, Garrison et al 1992. Studies on DA production have shown it to occur only during the stationary phase, coinciding with low levels of silicate in the medium (Subba Rao et al 1990, Bates et al 1991, Pan et al 1991). These observations suggest a possible relationship between silicate limitation and DA production.…”

Section: Introductionmentioning

confidence: 99%

Effects of silicate limitation on production of domoic acid, a neurotoxin, by the diatom Pseudo-nitzschia multiseries. I. Batch culture studies

Pan¹,

Rao²,

Mann³

et al. 1996

Mar. Ecol. Prog. Ser.

115

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ABSTRACT. Dornoic acid (DA) production by Pseudo-nitzschia multiseries (Hasle) was studied at various silicate concentrations and under silicate perturbation. Both slowly dividing and non-dividing population~ produced DA, and the production rates were inversely correlated with the ambient silicate concentrations. Production of DA was significantly enhanced when overall cell metabolism (i.e growth rate) declined as a result of silicate stress. Following silicate starvation, cultures supplemented with silicate registered uptake, but suspended DA production. Results suggest that luxury uptake of Si by P. multisenes may happen only in phys~ologically active populations, i.e, the exponential phase, but not in the stationary phase. There were 2 stages of DA production The first stage corresponded to a decline in growth caused by moderately low lcvels of remaining s~licate in the medium, wh.ile the second stage was caused by severe silicate limitation. The production rate during the second stage (13.67 to 30.20 fg DA cell-' d-') was about an order of magnitude higher than during the first stage (0.97 to 4.98 fg DA cell-' d-l). Increases and decreases in cellular DA content corresponded to decreases and increases in growth rates.KEY WORDS: Domoic acid . Pseudo-nitzschia multiseries . Silicate limitation . Batch culture INTRODUCTIONPseudo-nitzschia multiseries, formerly known as Pseudonitzschia pungens f. multiseries (Hasle, 1995), produces domoic acid (DA), which has caused amnesic shellfish poisoning (ASP) in Atlantic Canada (Addison & Stewart 1989). The ASP problem has now been observed on both the Atlantic and Pacific coasts of North America (Fritz et al. 1992, Garrison et al. 1992. Studies on DA production have shown it to occur only during the stationary phase, coinciding with low levels of silicate in the medium (Subba Rao et al. 1990, Bates et al. 1991, Pan et al. 1991). These observations suggest a possible relationship between silicate limitation and DA production. However, direct linkage between DA production and silicon depletion is unlikely, as silicate is neither a component of DA nor apparently involved in its synthesis.The magnitude of a diatom bloom is often directly related to the availability of silicon in sea water. Silicon regulates the growth and frustule formation of diatoms. Decreases in silicate concentrations to low or undetectable levels in marine and freshwater habitats during diatom blooms have been well documented (Paasche 1973a, Sommer & Stabel 1983, Egge & Aksnes 1992, Harrison et al. 1993.In cultures, silicate concentrations in the medium may regulate the yield of diatom cells (Taguchi et al. 1987). Cessation of cell division, which may be due to cessation of DNA synthesis (Darley & Volcani 1969, Sullivan & Volcani 1973, was found to accompany depletion of silicon in the culture medium (Lewin 1955, Lewin & Chen 1968, Vaulot et al. 1987, Brzezinski et al. 1990. Bates et al. (1991) first showed a connection between silicate limitation and DA production. Two of their 5 treatments with low s...

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Photosynthesis and growth of Nitzschia pungens f. multiseries Hasle, a neurotoxin producing diatom

Cited by 21 publications

References 25 publications

Effects of silicate limitation on production of domoic acid, a neurotoxin, by the diatom Pseudo-nitzschia multiseries. II. Continuous culture studies

Effects of silicate limitation on production of domoic acid, a neurotoxin, by the diatom Pseudo-nitzschia multiseries. II. Continuous culture studies

Intra- and interspecies differences in growth and toxicity of Pseudo-nitzschia while using different nitrogen sources

Effects of silicate limitation on production of domoic acid, a neurotoxin, by the diatom Pseudo-nitzschia multiseries. I. Batch culture studies

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