Magnesium deficiency in embryos of Xenopus laevis

Development ◽  
1977 ◽  
Vol 39 (1) ◽  
pp. 97-113
Author(s):  
John C. Miller ◽  
Richard Landesman
Keyword(s):  
Xenopus Laevis ◽  
Normal Development ◽  
Magnesium Deficiency ◽  
Deficiency Syndrome ◽  
Ion Concentration ◽  
Magnesium Ion ◽  
Magnesium Ions ◽  
Ion Content ◽  
Ion Concentrations ◽  
Rearing Temperature

Embryos of Xenopus laevis reared in media with various low (≤ 10-5 M) magnesium ion concentrations will exhibit differing degrees of a potentially lethal magnesium starvation syndrome depending on the ion concentration and rearing temperature. The higher the rearing temperature or the lower the magnesium ion content of the medium the more severely the syndrome will be expressed. (Normal development can be expected at temperatures 13–30 °C and magnesium ion concentrations > 10−5 M to 10−2 M.) The magnesium deficiency syndrome in Xenopus embryos is described in detail and compared with the normal and anucleolate conditions. The deficiency condition becomes manifest after hatching as retarded growth and differentiation with progressive paralysis and edema. At the same time alterations are observed in the pattern of soluble proteins. The use of magnesium ions as a probe for investigating developing systems is discussed.

Thermal stability of ribosomes from a thermophilic and a mesophilic fungus

1973 ◽  
Vol 19 (6) ◽  
pp. 761-763 ◽  
Author(s):  
H. M. Miller ◽  
M. G. Shepherd
Keyword(s):  
Thermal Stability ◽  
Ion Concentration ◽  
Magnesium Ion ◽  
Penicillium Notatum ◽  
Ribosomal Subunits ◽  
Ion Concentrations ◽  
Thermal Stability Of

Ribosomes and ribosomal subunits from the thermophile Penicillium duponti were found to be more thermostable than the corresponding particles from the mesophile Penicillium notatum. The thermostability of the ribosomes from both organisms was dependent on magnesium ion concentration. The dissociation of the 80-S ribosomes into 60-S and 40-S subunits occurred at higher magnesium ion concentrations for the mesophile than the thermophile.

Alkaline phosphatase of high and low molecular mass in human serum and bile: a comparative study of kinetic properties.

1980 ◽  
Vol 26 (3) ◽  
pp. 451-456
Author(s):  
P M Crofton ◽  
A F Smith
Keyword(s):  
Alkaline Phosphatase ◽  
Molecular Mass ◽  
High Molecular Mass ◽  
Magnesium Ion ◽  
Kinetic Properties ◽  
Zinc Ions ◽  
Magnesium Ions ◽  
Optimum Conditions ◽  
Ion Concentrations ◽  
Low Magnesium

Abstract We studied the kinetic properties of high- and low-molecular-mass forms of alkaline phosphatase purified from serum and bile, to clarify their interrelationships. They were found to share virtually identical kinetic properties, and to obey the same general kinetics as the liver-derived isoenzyme from serum and the low-molecular-mass isoenzyme from bile with regard to optimum conditions of assay, activation by magnesium ions, inhibition by L-homoarginine, inhibition by nickel and zinc ions, and inactivation by urea. Most of the characteristics such as Km (at low magnesium ion concentrations), Ki for L-homoarginine, and half-life for urea inactivation, were closely similar for low- and high-molecular-mass alkaline phosphatase. We conclude that these forms of alkaline phosphatase in plasma and bile are closely related. We discuss the possible nature of this relationship.

Alkaline phosphatase of high and low molecular mass in human serum and bile: a comparative study of kinetic properties.

1980 ◽  
Vol 26 (3) ◽  
pp. 451-456 ◽  
Author(s):  
P M Crofton ◽  
A F Smith
Keyword(s):  
Alkaline Phosphatase ◽  
Molecular Mass ◽  
High Molecular Mass ◽  
Magnesium Ion ◽  
Kinetic Properties ◽  
Zinc Ions ◽  
Magnesium Ions ◽  
Optimum Conditions ◽  
Ion Concentrations ◽  
Low Magnesium

Abstract We studied the kinetic properties of high- and low-molecular-mass forms of alkaline phosphatase purified from serum and bile, to clarify their interrelationships. They were found to share virtually identical kinetic properties, and to obey the same general kinetics as the liver-derived isoenzyme from serum and the low-molecular-mass isoenzyme from bile with regard to optimum conditions of assay, activation by magnesium ions, inhibition by L-homoarginine, inhibition by nickel and zinc ions, and inactivation by urea. Most of the characteristics such as Km (at low magnesium ion concentrations), Ki for L-homoarginine, and half-life for urea inactivation, were closely similar for low- and high-molecular-mass alkaline phosphatase. We conclude that these forms of alkaline phosphatase in plasma and bile are closely related. We discuss the possible nature of this relationship.

scholarly journals THE EFFECTS OF HYDROGEN ION CONCENTRATION UPON THE METAMORPHIC PATTERN OF THYROXIN- AND IODINE-TREATED TADPOLES

1942 ◽  
Vol 25 (4) ◽  
pp. 623-647
Author(s):  
Francis N. Marzulli
Keyword(s):  
Chemical Nature ◽  
Normal Development ◽  
Chemical Form ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Rate Of Penetration ◽  
Ion Concentrations ◽  
Hind Limbs ◽  
Environmental Fluid

1. It has been shown quantitatively that the degree of response of the hind limbs of tadpoles to the action of thyroxin is dependent upon the lengths of the limbs at the beginning of treatment. 2. Both the potency of the inducing substance and the rate of penetration of the substance into the animal might be involved in the effects of hydrogen ion concentration on induced development. 3. Changes in hydrogen ion concentration affect the inducing power of thyroxin and iodine differently. With thyroxin, it is the rate of penetration of the molecule which determines the amount of growth, but with iodine it is the chemical form in which the substance has entered the animal which is of prime importance. 4. The hydrogen ion concentration of thyroxin solutions does not affect their potency when they are injected into tadpoles. 5. Change in hydrogen ion concentration of the environment does not affect the potency of thyroxin injected into tadpoles. 6. When thyroxin is administered in the environmental solution its effects, as measured by increase in hind limb length are greater at higher than at lower hydrogen ion concentrations in the range tested. 7. Since the potency of thyroxin is unaffected by change in hydrogen ion concentration when the thyroxin solution is injected, the above fact (point 6) seems explicable only on the basis of differences in the rate of penetration of thyroxin into the animals at the different hydrogen ion concentrations. 8. These differences in penetration of the thyroxin at different hydrogen ion concentrations may be the result of a differential effect of hydrogen ion concentration upon the rate of metabolism of the animal. The metabolic rate is significantly greater when the tadpoles are kept in solutions of higher hydrogen ion concentration than when they are kept in solutions of low hydrogen ion concentration. It is postulated that the rate of metabolism, since it controls the rate of intake of the environmental fluid and therefore of dissolved thyroxin, also controls the amount of thyroxin-induced development. 9. Change in hydrogen ion concentration of iodine solutions affects their potency when injected into tadpoles. A peak of effectiveness is reached at about the neutral point, with a lowered efficiency as the hydrogen ion concentration is either increased or decreased from this point. 10. Change in hydrogen ion concentration of the environment affects the potency of iodine injected into tadpoles. The effect is similar to that noted in point 9. 11. The hydrogen ion concentration of the environment seems to affect the chemical nature of the iodine in solution in the environment. If this is so, it is possible that the differences in the metamorphic effects of iodine at different hydrogen ion concentrations are dependent upon the chemical form of iodine present. 12. The effect of hydrogen ion concentration on normal development is similar to that on thyroxin-induced development; an effect on the rate of metabolism of the animal causes increased growth in more acid solutions.

Effects of inorganic salts and of ouabain on some metabolic responses of rat cerebral cortex slices to cationic and electrical stimulations

1968 ◽  
Vol 46 (4) ◽  
pp. 355-362 ◽  
Author(s):  
S. Nakazawa ◽  
J. H. Quastel
Keyword(s):  
Rat Brain ◽  
Potassium Ion ◽  
Ion Concentration ◽  
Magnesium Ions ◽  
High Potassium ◽  
Glycine Uptake ◽  
Ion Concentrations ◽  
Cortex Slices ◽  
Electrical Impulses ◽  
Stimulation Of

The rate of glycine uptake, against a concentration gradient, into rat brain cortex slices, incubated in a physiological glucose medium, is proportional to the sodium ion concentration of the medium and is independent of whether choline chloride or sucrose is used to balance diminished levels of sodium ions. Choline, in contrast to sucrose, resembles sodium in the maintenance of stimulated brain respiration but cannot replace sodium for the stimulation of brain respiration by electrical impulses or by increased potassium ion concentrations. Electrical stimulation of rat brain slices, whilst resembling potassium stimulation in causing a fall in the level of ATP, differs from potassium stimulation in causing no diminution in the rate of glycine transport. This is considered to be due to the operation of two opposing processes: (a) increased glycine influx due to increased influx of sodium, and (b) diminished glycine influx due to a decreased ATP level.The stimulation of rat brain respiration brought about by the application of electrical impulses or by the presence of high potassium ion concentrations, and the uptake of glycine against a concentration gradient, are controlled by the activity of membrane-bound ATPase. This conclusion is supported by the following facts, (a) The presence of potassium ions is needed to obtain the optimal respiratory responses and the optimal rate of glycine uptake; (b) ouabain inhibits the influx of glycine whether the brain tissue is in the stimulated condition or not and it also inhibits stimulated brain respiration; (c) absence of magnesium ions, or a high concentration of magnesium ions, diminishes the effects of high potassium ion concentration or of electrical stimuli on brain respiration; and (d) high concentrations of calcium ions, which block ATPase, inhibit stimulated brain respiration.

Fission yeast tmsl protein abrogates normal development in Xenopus laevis embryos

1995 ◽  
Vol 204 (3) ◽  
pp. 198-202 ◽  
Author(s):  
Peter Wagner ◽  
Michael Hoever ◽  
Katrin Appel ◽  
Walter Kn�chel ◽  
Mathias Montenarh
Keyword(s):  
Xenopus Laevis ◽  
Fission Yeast ◽  
Normal Development ◽  
Xenopus Laevis Embryos

STUDY OF SOME FACTORS THAT AFFECT THE DISTRIBUTION OF NUCLEAR VOLUMES IN PREPARATIONS OF RAT LIVER NUCLEI

1967 ◽  
Vol 45 (7) ◽  
pp. 1175-1183 ◽  
Author(s):  
Roberto Umaña
Keyword(s):  
Rat Liver ◽  
Dna Content ◽  
Direct Relationship ◽  
Magnesium Ion ◽  
Homogenization Procedure ◽  
Ion Concentrations ◽  
Ph Values ◽  
Sucrose Solutions ◽  
Liver Nuclei ◽  
Calcium And Magnesium

The effect of the homogenization procedure, the centrifugation scheme, and the composition of the suspension medium on the distribution of nuclear volumes has been studied.It has been shown that the Waring Blendor not only destroys a greater number of the nuclei during homogenization, but also that this destruction is a selective one. At neutral pH values, no direct relationship appears to exist between the DNA content of the nuclei and their density. For this reason, purification in concentrated sucrose solutions produces a selective loss of the lighter nuclei, which includes small diploid stromal nuclei and some of the larger polyploid type of parenchymal nuclei.The study of the effect of increasing the calcium and magnesium ion concentrations (from 0.001 to 0.005 M) on the nuclear distribution showed that these ions produce a selective shrinkage and condensation of the nuclei, probably through different mechanisms.

A Study on the Influence of Cysteine and Magnesium Ions on Brain Dementia

2014 ◽  
Vol 487 ◽  
pp. 161-164
Author(s):  
Lu Yin ◽  
Shuang Yue Zhu
Keyword(s):  
Vascular Dementia ◽  
Plasma Homocysteine ◽  
Diagnosis And Treatment ◽  
Magnesium Ion ◽  
Disease Development ◽  
Mechanism Analysis ◽  
Magnesium Ions ◽  
Patients Âgés ◽  
Dementia Patients ◽  
Relationship Of

As the population ages, dementia disease is increasingly becoming the most concerned social problems. According to the cause of dementia, it can be divided into many kinds class, among them with Alzheimer's Disease (Alzheimers diseases, AD) and Vascular Dementia (Vascular Dementia, VD) are common. Data shows it accounts for nearly 60% of total AD dementia patients, VD (20%), but only 2% of patients could get timely diagnosis and treatment, make its cognitive damage to a certain extent suppress and improve. for untimely diagnosis and treatment, most patients makes the disease development worse. In recent years, studies have shown that plasma Homocysteine,Hcy levels associated with AD. And studies show that from the power of the risk factors to the mechanism analysis, dementia disease level correlation with magnesium ions. On this basis, this study of plasma homocysteine in patients with AD,VD and magnesium ion detection results were analyzed retrospectively. Discuss their levels between the distributio relationship of patients ages in AD and VD.

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