Effect of nutrient concentration on growth and saxitoxin production of Raphidiopsis raciborskii (Cyanophyta) interacting with Monoraphidium contortum (Chlorophyceae)

Vargas, Sarah Regina; Santos, Paulo Vagner dos; Bottino, Flávia; Calijuri, Maria do Carmo

doi:10.1007/s10811-019-01972-w

Cited by 11 publications

(8 citation statements)

References 41 publications

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“…According to the authors, STX provides an advantage to STX-producing cyanobacteria over non-STX-producing cyanobacteria by maintaining homeostasis at alkaline pH and Na + stress conditions, e.g., at high salt concentrations. These results might indicate that STX production is an adaptation to non-ideal conditions as reported from other studies [8,31,51].…”

Section: Saxitoxin and Environmental Variablessupporting

confidence: 80%

“…In the present study, the cyanobacterial biovolume in the dam zone (dominated by Raphidiopsis) was highest in the riverine zone and correlated with the lowest nutrient levels and the highest TN:TP ratios. This suggests that Raphidiopsis is adapted to low-P nutrient environments, as also observed for R. raciborskii by Casali et al [31] and Vargas et al [51]. Supporting this, Kenesi et al [52] showed that R. raciborskii had a higher growth performance in P-limited environments, but only when inorganic N was available.…”

Section: Environmental Variables and Cyanobacteriamentioning

confidence: 54%

“…For the STX-producing dinoflagellate Alexandrium sp., Granéli and Flynn [77] report that the STX production at low P levels may indicate an adaptation to nutrient limitation. Similarly, Vargas et al [51] report a high STX production by R. raciborskii at oligotrophic conditions due to adaptation to low-P levels, which might serve as a survival strategy. Frangópulos et al [78] state that toxin production under P-limitation enhances the interspecific competition by redirecting grazing pressure to non-toxic species.…”

Section: Saxitoxin and Environmental Variablesmentioning

confidence: 91%

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Influence of Environmental Factors on Occurrence of Cyanobacteria and Abundance of Saxitoxin-Producing Cyanobacteria in a Subtropical Drinking Water Reservoir in Brazil

Moraes

Rodrigues

Schlüter

et al. 2021

Water

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Blooms of cyanobacteria are frequent in Brazilian water reservoirs used for drinking water. The warning for the presence of potential toxin-producing cyanobacteria is typically based on time-consuming microscopy, rather than specific molecular detection of toxic genes in cyanobacteria. In this study, we developed a quantitative PCR assay for the detection of cyanobacteria producing the neurotoxin saxitoxin (STX). The assay targets the sxtA gene in the sxt gene cluster. Potential and dominant STX-producers in the Itupararanga reservoir were the genera Raphidiopsis, Aphanizomenon and Geitlerinema. Numbers of the sxtA gene varied from 6.76 × 103 to 7.33 × 105 cells mL−1 and correlated positively with SXT concentrations in the water. Concentrations of STX and the sxtA gene also correlated positively with TN:TP ratio and pH, but correlated negatively with inorganic nutrients and turbidity, confirming that regulation of the SXT production was impacted by environmental variables. In contrast, the occurrence of another cyanotoxin, microcystin, did not correlate with any environmental variables. The developed qPCR assay was found to be a rapid and robust approach for the specific quantification of potential STX-producing cyanobacteria and should be considered in future investigations on toxic cyanobacteria to provide an early warning of potential toxin episodes.

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Section: Saxitoxin and Environmental Variablessupporting

confidence: 80%

Section: Environmental Variables and Cyanobacteriamentioning

confidence: 54%

Section: Saxitoxin and Environmental Variablesmentioning

confidence: 91%

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Influence of Environmental Factors on Occurrence of Cyanobacteria and Abundance of Saxitoxin-Producing Cyanobacteria in a Subtropical Drinking Water Reservoir in Brazil

Moraes

Rodrigues

Schlüter

et al. 2021

Water

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“…Kellmann et al [ 46 ] analyzed the STX gene cluster in cyanobacteria and concluded that the target toxin synthesis may be regulated at the transcriptional level in response to the availability of phosphate and other environmental factors. The concentration of STX was notably higher in the biomass of Raphidiopsis raciborskii strain grown under oligotrophic rather than a super-eutrophic condition [ 47 ]. Nevertheless, though a similar tendency was observed in the current experiment, a significant relationship of Aphanizomenon gracile growth rate, IP concentrations, N:P ratio to STX concentrations was not revealed ( p > 0.05).…”

Section: Discussionmentioning

confidence: 99%

Interplay of Nutrients, Temperature, and Competition of Native and Alien Cyanobacteria Species Growth and Cyanotoxin Production in Temperate Lakes

Savadova

Mazur‐Marzec

Karosienė

et al. 2021

Toxins

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Global warming and eutrophication contribute to formation of HABs and distribution of alien cyanobacteria northward. The current study assessed how alien to Europe Sphaerospermopsis aphanizomenoides and Chrysosporum bergii will co-occur with dominant native Planktothrix agardhii and Aphanizomenon gracile species under changing conditions in temperate freshwaters. The experiments were carried out to examine the effect of nutrients and temperature on the growth rate of cyanobacteria, production of cyanotoxins, and interspecies competition. The highest growth rate was determined for A. gracile (0.43 day−1) and S. aphanizomenoides (0.40 day−1) strains at all the tested nutrient concentrations (IP and IN were significant factors). S. aphanizomenoides adapted to the wide range of nutrient concentrations and temperature due to high species ecological plasticity; however, A. gracile was able to suppress its dominance under changing conditions. Regularity between tested variables and STX concentration in A. gracile was not found, but IP concentration negatively correlated with the amount of dmMC-RR and other non-ribosomal peptides (NRPs) in P. agardhii strains. The relative concentration of NRPs in nontoxic P. agardhii strain was up to 3-fold higher than in MC-producing strain. Our study indicated that nutrients, temperature, and species had significant effects on interspecies competition. A. gracile had a negative effect on biomass of both alien species and P. agardhii.

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“…Cell growth and cellular STXs’ content in the toxic Alexandrium species vary according to environmental factors, such as temperature, salinity, light intensity, CO 2 , and nutrients [ 17 , 18 , 19 ]. As eutrophication is responsible for HABs, effects of nutrients on STX biosynthesis have been extensively studied in toxic cyanobacteria and marine dinoflagellates until now [ 17 , 20 , 21 ]. In addition, STXs accumulated in shellfish are detected in spring and autumn off the coasts of temperate regions, including western Mediterranean, Chile, New Zealand, and Korea [ 22 , 23 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Low Temperature and Cold Stress Significantly Increase Saxitoxins (STXs) and Expression of STX Biosynthesis Genes sxtA4 and sxtG in the Dinoflagellate Alexandrium catenella

et al. 2021

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Toxic dinoflagellate Alexandrium spp. produce saxitoxins (STXs), whose biosynthesis pathway is affected by temperature. However, the link between the regulation of the relevant genes and STXs’ accumulation and temperature is insufficiently understood. In the present study, we evaluated the effects of temperature on cellular STXs and the expression of two core STX biosynthesis genes (sxtA4 and sxtG) in the toxic dinoflagellate Alexandrium catenella Alex03 isolated from Korean waters. We analyzed the growth rate, toxin profiles, and gene responses in cells exposed to different temperatures, including long-term adaptation (12, 16, and 20 °C) and cold and heat stresses. Temperature significantly affected the growth of A. catenella, with optimal growth (0.49 division/day) at 16 °C and the largest cell size (30.5 µm) at 12 °C. High concentration of STXs eq were detected in cells cultured at 16 °C (86.3 fmol/cell) and exposed to cold stress at 20®12 °C (96.6 fmol/cell) compared to those at 20 °C and exposed to heat stress. Quantitative real-time PCR (qRT-PCR) revealed significant gene expression changes of sxtA4 in cells cultured at 16 °C (1.8-fold) and cold shock at 20®16 °C (9.9-fold). In addition, sxtG was significantly induced in cells exposed to cold shocks (20®16 °C; 19.5-fold) and heat stress (12®20 °C; 25.6-fold). Principal component analysis (PCA) revealed that low temperature (12 and 16 °C) and cold stress were positively related with STXs’ production and gene expression levels. These results suggest that temperature may affect the toxicity and regulation of STX biosynthesis genes in dinoflagellates.

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Effect of nutrient concentration on growth and saxitoxin production of Raphidiopsis raciborskii (Cyanophyta) interacting with Monoraphidium contortum (Chlorophyceae)

Cited by 11 publications

References 41 publications

Influence of Environmental Factors on Occurrence of Cyanobacteria and Abundance of Saxitoxin-Producing Cyanobacteria in a Subtropical Drinking Water Reservoir in Brazil

Influence of Environmental Factors on Occurrence of Cyanobacteria and Abundance of Saxitoxin-Producing Cyanobacteria in a Subtropical Drinking Water Reservoir in Brazil

Interplay of Nutrients, Temperature, and Competition of Native and Alien Cyanobacteria Species Growth and Cyanotoxin Production in Temperate Lakes

Low Temperature and Cold Stress Significantly Increase Saxitoxins (STXs) and Expression of STX Biosynthesis Genes sxtA4 and sxtG in the Dinoflagellate Alexandrium catenella

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