Indicators of Phosphorus and Nitrogen Deficiency in Five Algae in Culture

Healey, F. P.; Hendzel, L. L.

doi:10.1139/f79-195

Cited by 192 publications

(162 citation statements)

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“…The lack of upregulation under the P-reduced treatment is potentially a result of experimental conditions designed to upregulate P stress not being limiting enough. In the case of Microcystis, deeper P-limiting conditions may be required for widespread upregulation of genes involved in phosphate metabolism, including APase (Healey and Hendzel, 1979;Harke and Gobler, 2013). Previous studies have found that APase activity is independent of phosphate concentrations when they are above 0.2 mM in the environment (Nausch, 1998), much lower than those used in this study, and may in fact be linked to cellular N/C ratios in phytoplankton (Myklestad and Sakshaug, 1983;Neddermann and Nausch, 2004).…”

Section: Insights Into Physiological Responses Of Microcystis To Nutrmentioning

confidence: 59%

Nutrients drive transcriptional changes that maintain metabolic homeostasis but alter genome architecture in Microcystis

Steffen¹,

Dearth²,

Dill³

et al. 2014

The ISME Journal

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The cyanobacterium Microcystis aeruginosa is a globally distributed bloom-forming organism that degrades freshwater systems around the world. Factors that drive its dispersion, diversification and success remain, however, poorly understood. To develop insight into cellular-level responses to nutrient drivers of eutrophication, RNA sequencing was coupled to a comprehensive metabolomics survey of M. aeruginosa sp. NIES 843 grown in various nutrient-reduced conditions. Transcriptomes were generated for cultures grown in nutrient-replete (with nitrate as the nitrogen (N) source), nitrogen-reduced (with nitrate, urea or ammonium acting as the N sources) and phosphate-reduced conditions. Extensive expression differences (up to 696 genes for urea-grown cells) relative to the control treatment were observed, demonstrating that the chemical variant of nitrogen available to cells affected transcriptional activity. Of particular note, a high number of transposase genes (up to 81) were significantly and reproducibly up-regulated relative to the control when grown on urea. Conversely, phosphorus (P) reduction resulted in a significant cessation in transcription of transposase genes, indicating that variation in nutrient chemistry may influence transcription of transposases and may impact the highly mosaic genomic architecture of M. aeruginosa. Corresponding metabolomes showed comparably few differences between treatments, suggesting broad changes to gene transcription are required to maintain metabolic homeostasis under nutrient reduction. The combined observations provide novel and extensive insight into the complex cellular interactions that take place in this important bloom-forming organism during variable nutrient conditions and highlight a potential unknown molecular mechanism that may drive Microcystis blooms and evolution.

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Section: Insights Into Physiological Responses Of Microcystis To Nutrmentioning

confidence: 59%

Nutrients drive transcriptional changes that maintain metabolic homeostasis but alter genome architecture in Microcystis

Steffen¹,

Dearth²,

Dill³

et al. 2014

The ISME Journal

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“…Different macromolecular components are associated with different cell functions, with proteins linked to basic functions of biosynthesis and cell division, and lipids and polysaccharides serving mainly as intracellular reservoirs of carbon and energy (Geider et al, 1986). These changes in carbon allocation provide important insights into metabolic strategies adopted by phytoplankton in response to differing environmental conditions; for example under poor growth conditions (low-phosphorus) phytoplankton may preferentially synthesize storage products such as polysaccharide and/or lipid rather than protein (Healey & Hendzel, 1979;Ganff et al, 1986;Kilham et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Impact of phosphorus quota and growth phase on carbon allocation inChlamydomonas reinhardtii: an FTIR microspectroscopy study

Dean

Nicholson

Sigee

2008

European Journal of Phycology

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Batch cultures of Chlamydomonas reinhardtii were used to study carbon allocation in relation to growth phase and phosphorus availability. Cultures were grown at initial phosphorus (PO 4 -P) concentrations of 500 mg l À1 (high-P) and 50 mg l À1 (low-P).Cellular carbon allocation was monitored using Fourier transform infrared (FTIR) microspectroscopy with the ratio of the band intensities at 1736 cm À1 (lipid) and the 1180-950 cm À1 region (carbohydrate) to 1652 cm À1 (amide I) used as an index of changing carbon balance. Cellular phosphorus concentrations (P quota) were measured by energy dispersive X-ray microanalysis (EDXRMA). Both treatments entered stationary phase on day 18. Increased cell counts in the high-P treatment (max. 3.0 Â 10 6 cells ml À1 at stationary phase) led to a rapid decrease in external P availability to <20 mg l À1 during early log phase, with a subsequent decrease in P quota from 0.5% to <0.1% DW. The fall of P quota to <0.1% led to an increase in the lipid/protein ratio (0.13 to 0.23) and carbohydrate/protein ratio (0.37 to 1.57), with ratios increasing further (lipid:protein 1.85; carbohydrate:protein 2.77) in late stationary phase. In the low-P treatment external P concentrations (<20 mg l À1 from day 1) restricted population growth (max. 0.75 Â 10 6 cells ml À1 at stationary phase). P quotas fell to <0.1% in early log phase, with the carbohydrate/protein ratio increasing from 0.15 to 3.7 and remaining high into stationary phase while the lipid/ protein ratio increased from 0.2 to 1.2. In both treatments increasing synthesis of lipid and carbohydrate storage products resulted in an increased cell volume. Transfer of P-deficient cells (late stationary) to fresh media led to a rapid stimulation of growth, a rapid reduction in lipid/protein and carbohydrate/protein ratios, and decreased cell volumes.

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“…L'activité phosphatase alcaline jouerait donc le rôle d'un indicateur de carence en phosphore minéral. De nombreux auteurs ont démontré que l'activité phosphatase alcaline était étroitement liée aux quantités de phosphore minéral disponibles dans le milieu et que de fortes concentrations en phosphore minéral répriment la synthèse de l'enzyme (Dilenfeldt & Gibson 1975, Healey & Hendzel 1979, Cembella et al 1984-85, Jansson et al 1988). …”

Section: Discussion Et Conclusionunclassified

Variations nycthémérales de l'activité phosphatase alcaline d'une Diatomée :Synedra capitataet de deux Cyanobactéries :Microcystis aeruginosaetAphanizomenon flos aquae

Giraudet

Abrial

Berthon

et al. 1998

Ann. Limnol. - Int. J. Lim.

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The results we present here were on three quasi monospecific settlements : Synedra capitata (Diatom), Microcystis aeruginosa and Aphanizomenon flos aquae (Cyanobacteria). The alkaline phosphatase activity (APA) (EC : 3.1.3.1) exhibited a nycthemeral variation for Diatoms as well as Cyanobacteria, though every species had its own characteristic. Under similar experimental conditions, the enzymatic activity was, in the average, 32 times higher (per unit of biomass) for Microcystis aeruginosa than for Synedra capitata and 3 times higher for Microcystis aeruginosa than for Aphanizomenon flos aquae. Under LD (16 : 8), Synedra capitata and Aphanizomenon flos aquae had a maximal enzymatic activity during the day time (maximal APA around 425 umol pNPP/l/h at 5 a.m., 11 a.m. and 5 p.m. for the Diatom and around 850 umol pNPP/l/h at 11 a.m., 3 p.m. and 7 p.m. for the Cyanobacteria) while the enzymatic activity of Microcystis aeruginosa was maximal at the beginnique of the night time (maximal APA around 1500 (imol pNPP/l/h at 9 p.m.). The observed daily rythm disappeared when the samples were placed in the darkness (DD) or under permanent light (LL). In the last case (LL), the mean enzymatic activity of Microcystis aeruginosa was maximal and, on the contrary, the mean APA of both Synedra capitata and Aphanizomenon flos aquae was minimal. There was a difference between the phytoplanktonic species in the orthophosphate assimilation and in the capacity for mineralizing organic phosphorus because of the phosphatases. This difference in the enzymatic behaviour might explain ecological successions within the planktonic settlements.

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Indicators of Phosphorus and Nitrogen Deficiency in Five Algae in Culture

Cited by 192 publications

References 0 publications

Nutrients drive transcriptional changes that maintain metabolic homeostasis but alter genome architecture in Microcystis

Nutrients drive transcriptional changes that maintain metabolic homeostasis but alter genome architecture in Microcystis

Impact of phosphorus quota and growth phase on carbon allocation inChlamydomonas reinhardtii: an FTIR microspectroscopy study

Variations nycthémérales de l'activité phosphatase alcaline d'une Diatomée :Synedra capitataet de deux Cyanobactéries :Microcystis aeruginosaetAphanizomenon flos aquae

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