Soluble and membrane‐associated nitrate reductases in the dinoflagellate <i>Peridinium gatunense</i>

Witt, Federico G.; Stöhr, Christine; Ullrich, Wolfram R.

doi:10.1046/j.1469-8137.1999.00380.x

Cited by 5 publications

(3 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Shukla & Kashyap 1999) and dinoflagellates (Kristiansen 1983, Witt et al 1999. Temperature responses of NR are also similar: Witt et al (1999) found E a values for NR from Peridinium gatunense of 23 to 29 kJ mol -1 ; Kristiansen (1983), derived an E a of 38 kJ mol -1 for NR from Heterocapsa triqueta; and Gao et al (1993) calculated an E a of 36.5 kJ mol -1 for NR from Skeletonema costatum, all very similar to the overall value found in the present study.…”

Section: Temperature Effects On Nitrate Metabolismsupporting

confidence: 74%

Effects of temperature on growth rate, cell composition and nitrogen metabolism in the marine diatom Thalassiosira pseudonana (Bacillariophyceae)

Berges¹,

Varela²,

Harrison³

2002

Mar. Ecol. Prog. Ser.

141

View full text Add to dashboard Cite

Although temperature effects on phytoplankton growth and photosynthesis can be clearly demonstrated in the laboratory, their relevance in the field is much harder to establish. Recently, however, it has been recognized that temperature has a significant influence on nitrogen uptake. In particular, temperate marine diatom species may be limited by their ability to acquire nitrate at temperatures above approximately 16°C. In order to explore this idea, we grew the diatom Thalassiosira pseudonana at 8, 17 and 25°C, and compared cell composition, and rates of growth (µ), 15 N incorporation, calculated nitrate incorporation (the product of µ and cell N content), and the activity of nitrate reductase (NR), a key enzyme involved in nitrate incorporation. Cell N content, protein and volume remained relatively constant across different temperatures, but cell C, chlorophyll a (chl a), and C:N ratio increased with increasing temperature, suggesting that C metabolism was affected more strongly than N metabolism. Classical temperature models suggested that growth and various indices of nitrate metabolism all responded to temperature, with Q 10 values of close to 2 over the whole temperature range. However, Q 10 values over the interval from 8 to 17°C were higher than 2 and much lower than 2 between 17 and 25°C. Limitations to the Q 10 concept are considered. Temperature effects on different measures of nitrate metabolism were very similar, supporting the hypothesis that the effects of temperature on diatom nitrate metabolism are mediated at the level of NR activity. Recent biochemical data for NR also supports this idea.

show abstract

Section: Temperature Effects On Nitrate Metabolismsupporting

confidence: 74%

Effects of temperature on growth rate, cell composition and nitrogen metabolism in the marine diatom Thalassiosira pseudonana (Bacillariophyceae)

Berges¹,

Varela²,

Harrison³

2002

Mar. Ecol. Prog. Ser.

141

View full text Add to dashboard Cite

show abstract

“…Enhanced Fe reduction as a result of nitrate reductase activity was reported for Fedeplete marine diatom (24). Nevertheless, Fe-deplete P. gatunense, grown on nitrate or ammonia, reduce FeEDTA to the same extent (Table 2), as expected by the low membranebound nitrate reductase activity of P. gatunense (41).…”

Section: Iron(iii) Reduction By Laboratory Culturessupporting

confidence: 52%

Phytoplankton-Mediated Redox Cycle of Iron in the Epilimnion of Lake Kinneret

Shaked

Erel

Sukenik

2002

Environ. Sci. Technol.

View full text Add to dashboard Cite

The biological-mediated redox cycle of Fe was studied in the epilimnion of Lake Kinneret (Sea of Galilee), a mesotrophic lake in Israel. Multi-annual lake water sampling and incubation experiments were carried out to study Fe(III) reduction by natural phytoplankton populations and their possible role in inhibiting Fe(II) oxidation. The reduction characteristics of the dinoflagellate Peridinium gatunense, the dominant lake alga, were further examined in the laboratory. The steady-state concentration of Fe(II) calculated from the assessed reduction and oxidation rates was compared with Fe(II) measured in the lake in order to evaluate the significance of these processes to the lake Fe redox cycle. Nanomolar concentrations of Fe(II) were measured in the oxygenated, high pH, upper water layer of the lake throughout the year. Reduction rates of Fe by natural phytoplankton assemblages ranged between 0.1 and 10 nM/h. The highest reduction rates, determined in dinoflagellate-dominated lake waters, coincided with the highest concentrations of Fe(II) measured simultaneously in the lake. Iron(II) oxidation rates calculated from the measured lake Fe(II) and the obtained reduction rates were significantly slower than published abiotic Fe(II) oxidation rates. Indeed, Fe(II) oxidation rates measured in algal-enriched lake water were 30-fold slowerthan Fe(II) oxidation rates in natural water, demonstrating the potential for Fe(II) stabilization by the lake phytoplankton.

show abstract

“…Ceratium hirundinella was collected in higher numbers near a river inflow with higher NO 3 and PO 4 than the main reservoir (Kawabata and Kagawa, 1988). The mechanism explaining the effect of nitrates on blooms may be a low affinity for nitrate by nitrate reductase, which allows the dinoflagellate to outcompete other algae (Witt et al, 1999 for Peridinium gatunense). A decrease in N:P due to an increase in total phosphorus (TP) attributed to a wastewater treatment plant, caused a bloom of Ceratium hirundinella in Albert Falls Reservoir .…”

Section: A Dinoflagellate Bloomsmentioning

confidence: 99%