Cations, enzymes and control of cell metabolism

Wyatt, H. V.

doi:10.1016/0022-5193(64)90058-x

Cited by 37 publications

(13 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus calcium probably affects the general activity of the cell. Calcium, like potassium, affects various enzymes important in encrgy metabolism (Wyatt 1964). In addition it has also been shown to be important for normal intercellular adhesion III some tissues (Willmer 1965).…”

Section: Discussionmentioning

confidence: 99%

“…It stimulates a number of enzymes of the glycolytic pathway (Wyatt 1964) and has been shown to increase the oxygen uptake of brain and liver cells and the glycolysis of cancer cells and brain tissue (U ssing 1960). Many reports are also a vaila ble of its stimulating effect on the motility and metabolism of spermatozoa (Mann 1964;Dott and White 1964;Wallace and Wales 1964;Wales and O'Shea 1966).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Ions on the Development of the Pre-Implantation Mouse Embryo in Vitro

Rg¹

1970

Aust. Jnl. Of Bio. Sci.

View full text Add to dashboard Cite

SummaryThe effects of potassium, magnesium, calcium, phosphate, and sulphate ions on the development of two-cell mouse embryos to blastocysts were investigated.Both potassium and calcium ions are necessary for development and no blastocysts were formed in the absence of either of these ions. Normal development can occur in the presence of a wide range of concentration of potassium or calcium ions but at least 0·8 mM potassium and 0·4 mM calcium in the medium were necessary to obtain a large proportion of blastocysts. Lower concentrations of potassium suppressed cleavage. Oulture in calcium-deficient media led to a decrease in the rate of cleavage and an apparent breakdown of intercellular binding.Magnesium and phosphate ions were less important and even in the complete absence of these ions development into blastocysts could occur although the percentage of embryos forming blastocysts was decreased. Absence of sulphate ions did not affect the number of blastocysts developing.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effects of Ions on the Development of the Pre-Implantation Mouse Embryo in Vitro

Rg¹

1970

Aust. Jnl. Of Bio. Sci.

View full text Add to dashboard Cite

show abstract

“…Apart from the well-known effects of Ca2+ and Na+ on membrane permeability and structure in eukaryote cells, and the importance of Ca in exocytosis (Douglas & Poisner, 1964;Hales & Milner, 1968;Samli & Geschwind, 1968), Na+ and K+ are thought to be important in regulating some metabolic processes (Wyatt, 1964;Bygrave, 1967). In this context, it has been found that some glycolytic enzymes are activated by K+ and inhibited by Na+ and Li+ (Mahler & Cordes, 1966).…”

Section: Introductionmentioning

confidence: 99%

Ionic dependence of luteinizing‐hormone‐induced steroidogenesis in the rabbit ovary.

Bedwani¹,

Wong²

1975

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Investigations were made into the influence of the ionic environment on the steroidogenic response of the rabbit ovary to luteinizing hormone (LH).2. Removal of Ca2+ from the medium was without effect on the response to LH. A similar result was obtained in Ca2+-free medium containing EGTA.3. A tenfold increase in [Ca2+]. to mm, or the addition of La3+ or Eu3+ (0-25 mM) to medium containing the normal concentration of Ca2+, caused a marked inhibition of the response to LH.4. Removal of Na+ from the medium, and replacement by choline, had no effect on the response to LH. Replacement of Na+ by Li+ inhibited the response to the hormone strongly, but the addition of 4 mM-Li+ to normal medium was without effect.5. Removal of K+ from the medium inhibited LH-induced steroidogenesis, whereas a twentyfold increase in [K+]., to 100 mm had no effect.The response to LH was also unaffected by the absence of C1-. 6. Ouabain (10-4 M) inhibited the response to LH, but nupercaine (10-4 M) was without effect.7. The inhibitory effect of ouabain was reversed by the addition of 2 mm-NADP+ to the medium. In contrast, the inhibitory effect of Eu3+ persisted in the NADP+-rich medium.8. It is suggested that the intracellular ratio of Na+ (or Li+) to K+ is important for the expression of the steroidogenic response of the ovary to LH. Altered concentrations of these ions might affect the formation or availability of NADP+. The inhibitory effects of high [Ca2+]0 and lanthanide ions, however, are probably due to inhibition of hormonestimulated adenyl cyclase.

show abstract

“…Of interest is that ATP has different effects on NAD-ICDH in a digitonin-treated mitochondrial fraction with and without ABA (Table I). Since ICDH is sensitive to Mg2+ concentration (3), the inhibition of NAD-ICDH activity by ATP may be related to metal chelation being important in regulation (2,18) and ABA seems to mitigate the inhibition by ATP. We do not know the mechanism by which ABA is active to overcome the ATP effect.…”

Section: Resultsmentioning

confidence: 99%

Activation of O₂ Uptake and NAD-Specific Isocitrate Dehydrogenase in Mitochondria Isolated from Cotyledons of Castor Bean by cis, trans-Abscisic Acid

Tezuka

Yamamoto²,

Kondo³

1990

Plant Physiol.

View full text Add to dashboard Cite

The rate of 02 uptake and the activity of NAD-specific isocitrate dehydrogenase (NAD-ICDH) of mitochondria isolated from castor bean cotyledons were increased by added cis,trans-abscisic acid (ABA) in an in vitro system, while the NADP-specific isocitrate dehydrogenase (NADP-ICDH) was not affected by cis,trans-ABA. Trans,trans-ABA showed only a slightly inhibitory effect on 02 uptake. The Vmax value for the isotherm of isocitrate by the enzyme was also increased by cis,trans-ABA. The isocitrate Km value for the enzyme with cis,trans-ABA was calculated to be approximately 249.8 micromolar, while the S05 for the enzyme without the ABA was 151.6 micromolar. The n value calculated from the slopes of Hill plots of the reaction velocity of NAD-ICDH against isocitrate concentration was 1.5 in the mitochondrial fraction in the absence of ABA, and cis,trans-ABA treatment decreased the value to 1.0. Cis,trans-ABA also partly overcame the inhibition of NAD-ICDH activity by ATP. It has been reported that the respiratory rate (10) and ABA content (9) in grape, expressed on a per berry basis, increased during the ripening process after veraison (which means the onset of maturation [13]). These phenomena suggest a close relationship between ABA content and respiratory metabolism in mature tissues and organs of plants.Goldthwaite (5) observed that ABA stimulates oxygen consumption during senescence of Rumex leaf discs. Hourmant and Penot (6) reported that the rate of respiration of aerated potato tuber discs increased after a 24-h aging period with ABA in the dark. Tillberg et al. (16) found that respiration in Lemna gibba L. was significantly stimulated 2 to 7 d after ABA treatment. In the unicellular green algae, Chlorellafusca and Ankistrodesmus brauni, dark respiration was increased by ABA (17).In the present work, we studied the stimulating action of ABA on respiration of mitochondria isolated from cotyledons of castor beans and found evidence for the regulation of enzyme activity by ABA in an in vitro system. MATERIALS AND METHODS Plant MaterialsCastor beans (Ricinus communis L.) were grown under the conditions described previously by Kondo and Sugahara (7).The plants were grown for 2 to 3 weeks at 25 ± 0.5°C during the day and 20 ± 0.5°C at night with 70 ± 5% RH in an environmentally controlled glasshouse under natural light conditions. The growth substratum was composed of vermiculite: peat moss:perlite:fine gravel (2:2:1:1, v/v/v/v). A nutrient solution containing 8 g of magnesia lime and 4 g of hyponex per liter was supplied twice a week to each 1.9 L pot. Isolation of MitochondriaFive pairs of castor bean cotyledons were cut into small pieces (about 15 g) and homogenized with 45 mL of 25 mM Hepes buffer (pH 7.8) containing 0.35 M mannitol, 0.25 M sucrose, and 0.1 mg Na-2-mercaptobenzothiazole and 1 mg BSA per mL (14) using a Homo blender (18,000 rpm, 100 W, Sakuma Seisakusho, Ltd., Tokyo) at a quarter of maximum speed for 20 s. The homogenate was squeezed through four layers of gauze and centrifuged for 10...

show abstract

Cations, enzymes and control of cell metabolism

Cited by 37 publications

References 28 publications

Effects of Ions on the Development of the Pre-Implantation Mouse Embryo in Vitro

Effects of Ions on the Development of the Pre-Implantation Mouse Embryo in Vitro

Ionic dependence of luteinizing‐hormone‐induced steroidogenesis in the rabbit ovary.

Activation of O₂ Uptake and NAD-Specific Isocitrate Dehydrogenase in Mitochondria Isolated from Cotyledons of Castor Bean by cis, trans-Abscisic Acid

Contact Info

Product

Resources

About

Cations, enzymes and control of cell metabolism

Cited by 37 publications

References 28 publications

Effects of Ions on the Development of the Pre-Implantation Mouse Embryo in Vitro

Effects of Ions on the Development of the Pre-Implantation Mouse Embryo in Vitro

Ionic dependence of luteinizing‐hormone‐induced steroidogenesis in the rabbit ovary.

Activation of O2 Uptake and NAD-Specific Isocitrate Dehydrogenase in Mitochondria Isolated from Cotyledons of Castor Bean by cis, trans-Abscisic Acid

Contact Info

Product

Resources

About

Activation of O₂ Uptake and NAD-Specific Isocitrate Dehydrogenase in Mitochondria Isolated from Cotyledons of Castor Bean by cis, trans-Abscisic Acid