scholarly journals Influence of histones and calcium and magnesium ions on the ultrastructure of chromatin in isolated nuclei of Pinus silvestris L. root meristem

2015 ◽  
Vol 45 (1–2) ◽  
pp. 45-57
Author(s):  
Halina Michniewicz
Keyword(s):  
Root Meristem ◽  
The Other ◽  
Nuclear Proteins ◽  
Magnesium Ions ◽  
Pinus Silvestris ◽  
Control Material ◽  
Isolated Nuclei ◽  
Calcium And Magnesium ◽  
Calcium And Magnesium Ions

The width of chromatin fibrils in nuclei fixed in situ is about 10 nm. In nuclei isolated in the presence of Ca<sup>+2</sup> and Mg<sup>+2</sup> ions the fibrils coalesce, and thus their width secondarily increases, whereas in nuclei isolated without the presence of the cations the diameter of fibrils increases somewhat as compared with that in nuclei in situ, probably owing to absorption of nonchromatin nuclear proteins. Lysine histone extraction caused dispersion of condensed chromatin, and reintroduction of these proteins - its reconstruction. On the other hand, extraction and reintroduction of the arginine histone did not cause chromatin dispersion, but rather coalescence of the chromatin mass. Lysine histone extraction from material isolated in the presence of Ca<sup>+2</sup> and Mg<sup>+2</sup> ions caused the appearance of a large number of 10-nm fibrils, only sporadically seen in the control material, and disappearance of the 30-nm forms. Reintroduction of the lysine histone reduced the number of single fibrils and enhanced the appearance of coalescent form with 30 nm diameter. Removal of arginine histones did not produce disappearance of single fibrils, but reduced their diameter. Reintroduction of this fraction caused coalescence of chromatin threads, owing to which 90 per cent of the population consisted of fibrils with diameter around 30 nm.

scholarly journals The Responses of Heteroxenia (Alcyonaria) to Stimulation and to some Inorganic Ions

1956 ◽  
Vol 33 (3) ◽  
pp. 604-614
Author(s):  
G. A. HORRIDGE
Keyword(s):  
Refractory Period ◽  
Inorganic Ions ◽  
The Other ◽  
Conducting System ◽  
Magnesium Ions ◽  
Absolute Refractory Period ◽  
Potassium Sodium ◽  
Sodium Calcium ◽  
Calcium And Magnesium ◽  
Calcium And Magnesium Ions

1. In Heteroxenia there are two distinct kinds of response; one is the unco-ordinated rhythm of the autozooids; the other is the maintained spasm which is co-ordinated over the colony. 2. The absolute refractory period of the conducting system which co-ordinates the spasm of the colony is found to be 0.08 sec. 3. The actions of excesses of potassium, sodium, calcium and magnesium ions suggest that the rhythm resembles that of Scyphozoa. 4. The organization and overlap of the two conducting systems in the autozooid disk recall the scyphozoan pattern of two nerve nets. However, in Heteroxenia there is little evidence of interaction between the two systems.

The Role of Calcium and Magnesium Ions in Uptake of β-Amyloid Peptides by Microglial Cells

2006 ◽  
Vol 19 (3) ◽  
pp. 683-696 ◽  
Author(s):  
N. Choucair ◽  
V. Laporte ◽  
R. Levy ◽  
C. Tranchant ◽  
J.-P. Gies ◽  
...  
Keyword(s):  
Microglial Cells ◽  
Magnesium Ions ◽  
Amyloid Peptides ◽  
Β Amyloid ◽  
Calcium And Magnesium ◽  
Calcium And Magnesium Ions

USING MALIC ACID SOLUTIONS FOR THE HYDRATION OF VEGETABLE OILS AND LECITHIN PRODUCTION

2020 ◽  
Author(s):  
Л.А. МАРЧЕНКО ◽  
Т.Н. БОКОВИКОВА ◽  
Е.В. ЛИСОВАЯ ◽  
С.А. ИЛЬИНОВА ◽  
Е.П. ВИКТОРОВА
Keyword(s):  
Malic Acid ◽  
Complex Compounds ◽  
Point Of View ◽  
Magnesium Ions ◽  
Ph Values ◽  
Calcium And Magnesium ◽  
The Stability ◽  
The Cost ◽  
Calcium And Magnesium Ions

Исследована возможность применения яблочной кислоты (ЯК) в качестве гидратирующего агента для перевода негидратируемых форм фосфолипидов в гидратируемые. Выбор ЯК обусловлен ее стоимостью, которая в 1,5 раза меньше стоимости янтарной кислоты, широко применяемой в качестве гидратирующего агента, а также большей доступностью с точки зрения промышленного производства. Исследование процесса комплексообразования и определение состава комплексных соединений ЯК с ионами кальция и магния осуществляли методом потенциометрического титрования. Установлено, что внесение в раствор ЯК ионов кальция и магния приводит к снижению значений рН, что свидетельствует о наличии комплексообразования в указанных системах. Наиболее устойчивыми являются комплексы ионов кальция и магния с непротонированным лигандом при соотношении Ме2 : лиганд 1 : 1. В процессе комплексообразования ионы Ca2 и Mg2 вытесняют протоны только карбоксильных групп ЯК, которая с ионами кальция образует более устойчивые комплексы, чем с ионами магния. Показано, что устойчивость комплексов ЯК с ионами кальция и магния значительно выше, чем устойчивость комплексов фосфатидилсеринов и фосфатидных кислот с указанными ионами. Использование водных растворов ЯК в качестве гидратирующего агента позволит повысить эффективность процесса гидратации и увеличить выход фосфолипидов и, следовательно, готового продукта лецитина. The possibility of using malic acid (MA) as a hydrating agent for converting non-hydrated forms of phospholipids into hydrated ones has been investigated. The choice of MA is due to its cost, which is 1,5 times less than the cost of succinic acid, as well as greater availability from the point of view of industrial production. The study of the complexation process and determination of the composition of complex compounds of MA with calcium and magnesium ions was carried out by the method of potentiometric titration. It was found that the introduction of calcium and magnesium ions into the MA solution leads to a decrease in pH values, which indicates the presence of complexation in these systems. Complexes of calcium and magnesium ions with an unprotected ligand at a ratio of ME2 : ligand 1 : 1 are the most stable. In the process of complexing, Ca2 and Mg2 ions displace protons only of the carboxyl groups of MA, which forms more stable complexes with calcium ions than with magnesium ions. It is shown that the stability of MA complexes with calcium and magnesium ions is significantly higher than the stability of phosphatidylserine and phosphatidic acid complexes with these ions. Using water solutions of MA as a hydrating agent will increase the efficiency of the hydration process and increase the yield of phospholipids and, consequently, the finished product lecithin.

STUDIES CONCERNING THE DETERMINATION OF CALCIUM AND MAGNESIUM IONS IN THE DUMBRAVITA AREA DRINKING WATER (FOUNTAIN WATER)

2020 ◽  
Vol 34 (1) ◽  
pp. 17-24
Author(s):  
Aurica Pop ◽  
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Photometric Method ◽  
Magnesium Ions ◽  
Precise Analysis ◽  
Calcium And Magnesium ◽  
Cost Efficient ◽  
Calcium And Magnesium Ions

The paper showcases research conducted with the purpose of determining the Ca2+ and Mg2+ ions in the drinking water (fountain water) of a common household located in Dumbravita, Maramures County, Romania. The photometric method was used for this goal, as well as a Calcium and Magnesium Photometer. This study argues about implementing cost efficient techniques and precise analysis in order to determine Ca and Mg ions in the water samples.

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