Nature of the calcium effect in phosphate uptake by barley roots

1966 ◽  
Vol 24 (2) ◽  
pp. 328-332 ◽  
Author(s):  
A. H. Hyde
Keyword(s):  
Phosphate Uptake ◽  
Calcium Effect

Verification of anoxic phosphate uptake as the main biochemical mechanism of the “dephanox” process

1997 ◽  
Vol 35 (10) ◽  
pp. 87-94 ◽  
Author(s):  
R. Sorm ◽  
J. Wanner ◽  
R. Saltarelli ◽  
G. Bortone ◽  
A. Tilche
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Uptake Rate ◽  
Phosphate Uptake ◽  
Biochemical Mechanism ◽  
Batch Experiments ◽  
Batch Tests ◽  
Genetic Probes ◽  
Activated Sludge Systems ◽  
Removal System

The phenomenon of anoxic phosphate uptake with simultaneous denitrification was studied. For this purpose kinetic batch tests have been carried out by using the activated sludge samples from three modifications of nutrient removal activated sludge systems: two based on an anaerobic-anoxic-oxic (A2/O) system and a third on an anaerobic-oxic (A/O) system. The results showed significant differences in anoxic phosphate uptake rate between activated sludge which was alternatively exposed to anoxic conditions and activated sludge from the A/O arrangement. These differences were also accompanied by different denitrification rates. Simultaneously with batch experiments the microscopic observation of activated sludge samples was carried out. Neisser and Gram stained samples showed clear differences in shape, size and distribution of polyphosphate accumulating bacteria between A2/O and A/O Processes. Moreover, experiments performed using genetic probes confirmed the differences in microbiological composition of activated sludge samples from different nutrient removal system arrangements.

Effect of calcium on transport characteristics of cultured proximal renal cells

1985 ◽  
Vol 249 (3) ◽  
pp. F346-F355
Author(s):  
L. M. Sakhrani ◽  
N. Tessitore ◽  
S. G. Massry
Keyword(s):  
Phosphate Uptake ◽  
Cytosolic Calcium ◽  
Ruthenium Red ◽  
Extracellular Calcium ◽  
Transport Processes ◽  
Renal Cells ◽  
Sodium Uptake ◽  
Calcium Loading ◽  
Sodium Dependent ◽  
Acute Changes

We examined the effects of acute changes in extracellular and intracellular calcium on transport processes in primary culture of proximal rabbit renal cells. A change in extracellular calcium from 0 to 3 mM inhibited amiloride-sensitive sodium uptake by 30%, and this effect was maximal at 1 mM calcium. Other polyvalent cations (Mn2+, Mg2+, La3+, and Ba2+) produced quantitatively similar inhibition of amiloride-sensitive sodium uptake compared with calcium. An increase in cytosolic calcium produced by calcium loading (20 mM) or by A23187 (20 microM) resulted in an inhibition of 25-40% of amiloride-sensitive sodium uptake. Moreover, quinidine (10(-4)M) and ruthenium red (3 microM), agents presumed to increase cytosolic calcium, inhibited amiloride-sensitive sodium uptake by 20-60%. Both these agents also inhibited sodium-dependent phosphate uptake by 20% but had no effect on ouabain-sensitive 86Rb+ uptake or on sodium-dependent alpha-methylglucoside uptake. Our data indicate that increases in extracellular calcium inhibit amiloride-sensitive sodium uptake and increases in cytosolic calcium inhibit sodium-dependent phosphate and amiloride-sensitive sodium uptakes. The effect of extracellular calcium may be due to charge screening and/or binding to the negatively charged plasma membrane or due to alterations in membrane fluidity.

scholarly journals 5-HT1A and histamine H1 receptors in HeLa cells stimulate phosphoinositide hydrolysis and phosphate uptake via distinct G protein pools.

1991 ◽  
Vol 266 (1) ◽  
pp. 372-379 ◽  
Author(s):  
J R Raymond ◽  
F J Albers ◽  
J P Middleton ◽  
R J Lefkowitz ◽  
M G Caron ◽  
...  
Keyword(s):  
G Protein ◽  
Hela Cells ◽  
Phosphate Uptake ◽  
Phosphoinositide Hydrolysis ◽  
Histamine H1 Receptors

Quantitative requirement for ATP for active transport in isolated renal cells

1986 ◽  
Vol 251 (1) ◽  
pp. C120-C127 ◽  
Author(s):  
N. Tessitore ◽  
L. M. Sakhrani ◽  
S. G. Massry
Keyword(s):  
Atpase Activity ◽  
Active Transport ◽  
Phosphate Uptake ◽  
Quantitative Relationship ◽  
Similar Degree ◽  
Renal Cells ◽  
Stepwise Manner ◽  
Sodium Gradient ◽  
Sodium Dependent ◽  
86Rb Influx

We investigated the quantitative relationship between cellular ATP concentration and Na+-K+-ATPase activity as measured by ouabain-sensitive 86Rb influx in rabbit proximal renal cells. Cellular ATP was reduced in a stepwise manner by rotenone (10(-7) to 10(-5) M) and was increased by 10 mM adenosine. During these maneuvers, ouabain-sensitive 86Rb influx was linearly related to cellular ATP and did not saturate up to 9.9 mM ATP. In contrast, Na+-K+-ATPase activity in membranes prepared from these cells saturated at 2.0 mM ATP at various sodium (10-100 mM) and potassium (4-100 mM) concentrations. Sodium-dependent phosphate uptake and alpha-methylglucoside (alpha-MG) uptake were both inhibited to a similar degree when cellular ATP was reduced. We conclude that 1) the ATP requirement for saturation of Na+-K+-ATPase is higher in intact renal cells than in the membranes, and 2) the uptake of phosphate and alpha-MG are similarly influenced by reduction in ATP. This effect of ATP on phosphate and AMG uptake is most likely an indirect one and is secondary to changes in the sodium gradient across the cell.

Influence of phosphate status on phosphate uptake kinetics of maize (Zea mays) and soybean (Glycine max)

1990 ◽  
Vol 124 (2) ◽  
pp. 175-182 ◽  
Author(s):  
A. Jungk ◽  
C. J. Asher ◽  
D. G. Edwards ◽  
D. Meyer
Keyword(s):  
Zea Mays ◽  
Glycine Max ◽  
Phosphate Uptake ◽  
Uptake Kinetics ◽  
Kinetics Of

Anaerobic Phosphate Uptake by Barley Plants

1969 ◽  
Vol 20 (1) ◽  
pp. 12-24 ◽  
Author(s):  
A. W. D. LARKUM ◽  
B. C. LOUGHMAN
Keyword(s):  
Phosphate Uptake

The response of planktonic phosphate uptake and turnover to ultraviolet radiation in Lake Erie

2002 ◽  
Vol 59 (5) ◽  
pp. 778-786 ◽  
Author(s):  
C D Allen ◽  
R E.H Smith
Keyword(s):  
Ultraviolet Radiation ◽  
Lake Erie ◽  
Radiation Treatment ◽  
Phosphate Uptake ◽  
Ultraviolet B ◽  
Phosphate Limitation ◽  
Bacterial Cells ◽  
Near Surface ◽  
Ambient Concentrations ◽  
Uptake Activity

The hypothesis that ambient ultraviolet radiation (UVR), at near-surface intensities, may diminish phosphorus availability to phytoplankton was tested in Lake Erie in July and August of 1998 and 1999. Relative to samples exposed to photosynthetically active radiation (PAR, 400–700 nm) only, those exposed to ultraviolet-B (UVB, 280–320) and (or) ultraviolet-A (UVA, 320–400 nm) in natural sunlight, or kept in darkness, had diminished phosphate uptake rates at elevated (1 µM P) dissolved phosphate concentrations. By contrast, the specific uptake rate of dissolved phosphate at ambient concentrations (turnover rate) was not significantly affected by UVR or darkness. Turnover was usually dominated by particles smaller than 0.8 µm, whereas uptake from elevated concentrations was dominated by larger particles. The size distribution of turnover and uptake activity was not affected by radiation treatment. Chlorophyll a concentrations were decreased by sufficient exposure to UVB and (or) UVA and increased by deprivation of PAR (dark controls), but the concentration of bacterial cells was unaffected. The results showed that UVR inhibited the phosphate uptake potential of larger, probably algal, plankton but did not change the apparent severity of phosphate limitation at ambient concentrations.

Inorganic phosphate uptake in Trypanosoma cruzi is coupled to K+ cycling and to active Na+ extrusion

2013 ◽  
Vol 1830 (8) ◽  
pp. 4265-4273 ◽  
Author(s):  
C.F. Dick ◽  
A.L.A. Dos-Santos ◽  
D. Majerowicz ◽  
L.S. Paes ◽  
N.L. Giarola ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Inorganic Phosphate ◽  
Phosphate Uptake
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