Solution calcium concentration and application date effects on pod calcium uptake and distribution in florunner and tifton‐8 peanut

1989 ◽  
Vol 12 (1) ◽  
pp. 37-52 ◽  
Author(s):  
Halina Smal ◽  
Craig S. Kvien ◽  
Malcolm E. Sumner ◽  
Alexander S. Csinos
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Application Date

Invariance of Stoichiometry of the Sarcoplasmic Reticulum Calcium Pump at Physiological Calcium Concentrations – a Reevaluation

1985 ◽  
Vol 40 (7-8) ◽  
pp. 571-575 ◽  
Author(s):  
Wilhelm Hasselbach ◽  
Andrea Migala
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Level ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Atp Hydrolysis ◽  
Calcium Pump ◽  
Oxalate Precipitation ◽  
Sarcoplasmic Reticulum Calcium ◽  
Internal Calcium ◽  
External Calcium

Abstract The decline of the transport ratio of the sarcoplasmic calcium pump observed in a recent study (A. results from the retardation of calcium oxalate precipitation at low calcium/protein ratios. The prevailing high internal calcium level supports a rapid calcium backflux and a compensatory ATP hydrolysis during net calcium uptake which reduces the transport ratio. Yet, the determined calcium back­ flux does not fully account for the decline of the transport ratio. A supposed modulation of the stoichiometry of the pump by external calcium (0.1 μм) is at variance with results of previous studies showing a constant transport ratio of two in the same calcium concentration range.

The Effect of Calcium Concentration on Calcium Uptake by Bone Cells Treated with Thyrocalcitonin (TCT) Hormone

Endocrinology ◽  
1973 ◽  
Vol 92 (2) ◽  
pp. 550-555 ◽  
Author(s):  
ARIEH HARELL ◽  
ITZHAK BINDERMAN ◽  
GIDEON A. RODAN
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Bone Cells

The interaction of calcium and hydrogen ions in the nodulation of subterranean clover

1958 ◽  
Vol 9 (4) ◽  
pp. 464 ◽  
Author(s):  
JF Loneragan ◽  
EJ Dowling
Keyword(s):  
Calcium Ions ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Large Degree ◽  
Hydrogen Ions ◽  
Measurable Effect ◽  
Water Culture ◽  
Calcium Requirement

A study was made of the effects of calcium and hydrogen ions on the nodulation of subterranean clover (Trifolium subterraneum L.) in water culture. A compound interaction was found. At pH 4.0 or less no nodules were formed at any calcium concentration. At a 0.01mM calcium concentration no nodules were formed at any pH used. Above these critical values, almost maximum nodulation could be obtained by an increase in either calcium concentration or pH, so that each factor was to a large degree replaceable by the other. Calcium and hydrogen ions in the range of concentrations which produced these marked interactions on nodulation had no measurable effect on plant growth (nitrate was supplied in solution). The effects of calcium and hydrogen ions on the growth of the Rhizobium strain used were also markedly different from their effects on nodulation. Hydrogen ions had a dominating effect on Rhizobium growth, while calcium ions had no effect at any pH and were required at most in trace amounts. Hydrogen ions depressed calcium uptake by the plants. It is suggested that, in the range of concentrations where they were replaceable, the effects of calcium and hydrogen ions on nodulation were through their influence on the level of calcium in the plants. It is concluded that the calcium requirement for nodulation of subterranean clover is higher than for growth of the host plant or for growth of Rhizobium.

The regulation of haemolymph calcium concentration of the crab Carcinus maenas (L.)

1976 ◽  
Vol 64 (1) ◽  
pp. 149-157
Author(s):  
P. Greenaway
Keyword(s):  
Body Weight ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Sea Water ◽  
Calcium Influx ◽  
Carcinus Maenas ◽  
Ionic Form ◽  
Calcium Balance ◽  
Active Calcium ◽  
The Difference

After acclimation, Carcinus can maintain calcium balance in dilute (35–100%) but not in low calcium sea water. 71% of total haemolymph calcium (9–54 +/− 0–42 mM) was in ionic form as compared with 90–9%(9–9mM) in sea water. On acclimation to dilute sea water the calcium activity of the haemolymph was greater than that of the medium, the difference being maintained by active calcium uptake. Carcinus is highly permeable to Ca2+, influx from sea water being 0–513 +/− 0–07 mumoles g-1 h-1 and the time constant for calcium influx 4-3 +/− 0–48 h. Calcium space represented ca. 25% wet body weight independent of body size or salinity of acclimation medium.

Contractile proteins and sarcoplasmic reticulum in physiologic cardiac hypertrophy

1981 ◽  
Vol 241 (2) ◽  
pp. H263-H267 ◽  
Author(s):  
A. Malhotra ◽  
S. Penpargkul ◽  
T. Schaible ◽  
J. Scheuer
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Calcium Binding ◽  
Wistar Rats ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Contractile Proteins ◽  
Heart Weight ◽  
Female Wistar Rats ◽  
Female Control

To study effects of physiologic hypertrophy on contractile protein ATPases and sarcoplasmic reticulum, hypertrophy was caused in female Wistar rats by a chronic swimming program. Nonhypertrophied hearts of female control sedentary rats and rats made to run on a treadmill program were also examined. The swimming program, but not the running program, resulted in a significant increase in heart weight. Actomyosin ATPase activity was also increased by 15% in the hearts of swimmers but not runners. Similar increases were observed for Ca2+-activated myosin ATPase activity and actin-activated ATPase of myosin. Sarcoplasmic reticulum from the hearts of swimmers showed increased calcium binding and calcium uptake as a function of time and of calcium concentration. Sarcoplasmic reticulum ATPase activities were not altered by hypertrophy. These findings in physiologic hypertrophy contrast with those of pathologic hypertrophy in which ATPase activity of contractile proteins and calcium binding and uptake of sarcoplasmic reticulum have generally been found to be depressed.

scholarly journals CALCIUM METABOLISM IN HELA CELLS AND THE EFFECTS OF PARATHYROID HORMONE

1968 ◽  
Vol 36 (3) ◽  
pp. 567-582 ◽  
Author(s):  
André Bernard Borle
Keyword(s):  
Parathyroid Hormone ◽  
Hela Cells ◽  
Calcium Metabolism ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Cell Monolayer ◽  
Metabolic Inhibitors ◽  
Calcium Balance ◽  
Cell Coat ◽  
Cellular Calcium

Calcium metabolism was investigated in HeLa cells. 90% of the calcium of the cell monolayer is bound to an extracellular cell coat and can be removed by trypsin-EDTA. The calcium concentration of the naked cell, freed from its coat, is 0.47 mM. The calcium concentration of the medium does not affect the concentration of the naked cell calcium. However, the calcium of the cell coat is proportional to the calcium concentration in the medium. Calcium uptake into the cell coat increases with increasing calcium concentration of the medium, whereas uptake by the naked cell is independent of the calcium of the medium. Anaerobic conditions and metabolic inhibitors do not inhibit calcium uptake by the cell, a fact suggesting that this transfer is a passive phenomenon. The calcium in the extracellular cell coat, was not affected by parathyroid hormone. In contrast, the hormone increased the cellular calcium concentration by stimulating calcium uptake or by enhancing calcium binding to some cell components. These results suggest that, contrary to current thinking, parathyroid hormone influences the cellular calcium balance by mobilizing calcium from the extracellular fluids in order to increase its concentration in some cellular compartment. It is proposed that these effects can enhance calcium transport.

scholarly journals Calcium transport in intact human erthrocytes.

1976 ◽  
Vol 68 (1) ◽  
pp. 29-41 ◽  
Author(s):  
G Plishker ◽  
H J Gitelman
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Calcium Content ◽  
Ion Composition ◽  
Inhibitory Effects ◽  
Sodium Potassium ◽  
Tetramethylammonium Chloride ◽  
Low Concentrations ◽  
Net Uptake ◽  
External Calcium

Intact human erythrocytes can be readily loaded with calcium by incubation in hypersomotic media at alkaline pH. Erythrocyte calcium content increases from 15-20 to 120-150 nmol/g hemoglobin after incubation for 2 h at 20 degree C in a 400 mosmol/kg, pH 7.8 solution containing 100 mM sodium chloride, 90 mM tetramethylammonium chloride, 1 mM potassium chloride, and 10 mM calcium chloride. Calcium uptake is a time-dependent process that is associated with an augmented efflux of potassium. The ATP content in these cells remains at more than 60% of normal and is not affected by calcium. Calcium uptake is influenced by the cationic composition of the external media. The response to potassium is diphasic. With increasing potassium concentrations, the net accumulation of calcium initially increases, becoming maximal at 1 mM potassium, then diminishes, falling below basal levels at concentrations above 3 mM potassium. Ouabain inhibits the stimulatory effect of low concentrations of potassium. The inhibitory effects of higher concentrations of potassium are ouabain insensitive and independent of the external calcium concentration. Sodium also inhibits calcium uptake but this inhibition can be modified by altering the external concentration of calcium. The effux of calcium from loaded erythrocytes is not significantly altered by changes in osmolality, medium ion composition, or ouabain. It is concluded that hypertonicity increases the net uptake of calcium by increasing the influx of calcium and that some part of the sodium potassium transport system is involved in this influx process.

EFFECT OF THE EXTERNAL CONCENTRATION OF CALCIUM ON THE POSTMOULT UPTAKE OF CALCIUM IN BLUE CRABS (CALLINECTES SAPIDUS)

1994 ◽  
Vol 188 (1) ◽  
pp. 1-9
Author(s):  
D Neufeld ◽  
J Cameron
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Callinectes Sapidus ◽  
Free Calcium ◽  
Blue Crabs ◽  
Electrochemical Gradient ◽  
External Concentration ◽  
High Calcium ◽  
Reduced Rate ◽  
Active Transport System

The rate of calcium uptake in blue crabs (Callinectes sapidus Rathbun) acclimated to 2 sea water with a calcium concentration of 1.4 mmol l-1 was dependent on the magnitude and direction of the electrochemical gradient for calcium. When transferred to water with a high calcium concentration (6 mmol l-1), the electrochemical gradient for calcium favoured diffusive influx, and calcium uptake and apparent H+ excretion increased by approximately 50 %. When transferred to water with a low calcium concentration (0.10 mmol l-1), where the electrochemical gradient for calcium strongly favoured diffusive efflux, calcium uptake ceased but apparent H+ excretion continued at a reduced rate. Crabs regulated the free calcium concentration in their blood at approximately 8 mmol l-1 when the external concentration of calcium was 1.4 mmol l-1 or higher, but the concentration of free calcium in the blood decreased to 5.6 and 4.6 mmol l-1, respectively, at external concentrations of calcium of 0.25 and 0.10 mmol l-1. Crabs transferred to water with 0.10 mmol l-1 calcium for the first 2 days after moult accumulated only 2.5 g calcium kg-1 wet mass, about one-quarter of the mass normally accumulated. Seawater-acclimated crabs transferred to 2 salinity at 1 day postmoult took up calcium at a reduced rate, indicating that a period of acclimation is necessary for a component of the active transport system to increase its capacity, for diffusive efflux to be reduced, or for both to occur.

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