Wyniki wyszukiwania - Biblioteka Nauki

1

Calcium ions in the pig pineal gland - an ultracytochemical study

100%

Lewczuk B. , Bulc M. , Prusik M. , Przybylska-Gornowicz B.

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tom 12

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nr 4

335-346

EN

The aim of the study was to analyze the distribution of calcium ions in the pig pineal gland at the level of electron microscopy. The investigations were performed on the pineals obtained immediately after slaughter (performed between 11:30 and 12:00 a.m.) from 4-month-old gilts. The fixation procedures were conducted with the use of pyroantimonate, which reacted with calcium ions and formed electron dense precipitates. The precipitates were found both in the intercellular spaces and in cells - pinealocytes, gial cells, endothelial cells and fibroblasts. The precipitates were much more numerous in the intercellular spaces than in the cells. Amount and distribution of precipitates differed significantly between pinealocytes, therefore two types of cells were distinguished. The first type of pinealocytes included cells containing a small or moderate amount of precipitates. They were usually characterized by light or dark cytoplasm and large variability in number and structure of dense bodies. Pinealocytes classified to the second type possessed large or very large content of precipitates. These cells were characterized by electron dense cytoplasm and showed the presence of numerous dense bodies. In both types of pinealocytes, precipitates were present in the nucleus and in the cytoplasm. In nuclei, precipitates were numerous in nucleoplasma and rather infrequently noted between membranes of the nuclear envelope. In the cytoplasm deposits were found in mitochondria, vesicles and cisterns of smooth endoplasmic reticulum, in the Golgi apparatus and in cytosol. The amount of precipitates in glial cells, endothelial cells and fibrocytes was lower than in pinealocytes.

PL

Celem pracy była analiza ultracytochemiczna rozmieszczenia jonów wapniowych w szyszynce świni domowej. Badano szyszynki pobrane bezpośrednio po uboju (wykonanym między godz. 11:30 a 12:00) od loszek w wieku ok. 4 miesięcy. Do utrwalania gruczołów zastosowano pyroantymonian potasu, co umożliwiło związanie jonów wapniowych w postaci elektronowo gęstych precypitatów, których rozmieszczenie określono za pomocą mikroskopu elektronowego. Precypitaty występowały w przestrzeni międzykomórkowej oraz w komórkach: pinealocytach, komórkach glejowych, komórkach śródbłonka naczyń włosowatych i fibrocytach. Zawartość złogów pyroantymonianu wapnia była znacznie większa w przestrzeni zewnątrzkomórkowej niż wewnątrz komórek. Ze względu na ilość i lokalizację precypitatów możliwe było wyróżnienie dwóch typów pinealocytów. Pierwszy z nich stanowiły komórki zawierające małą lub średnią ilość precypitatów. Komórki te charakteryzowały się elektronowo jasną lub elektronowo gęstą cytoplazmą, a skład ciałek gęstych był zróżnicowany pod względem ilościowym i jakościowym. Drugi typ pinealocytów stanowiły komórki z dużą lub bardzo dużą zawartością precypitatów. Najczęściej charakteryzowały się one elektronowo gęstą cytoplazmą oraz obecnością bardzo licznych ciałek gęstych. W obu typach pinealocytów precypitaty występowały zarówno w jądrze komórkowym, jak i w cytoplazmie. W jądrze stosunkowo liczne precypitaty o zróżnicowanych wymiarach stwierdzono w obrębie chromatyny, natomiast jedynie sporadycznie obserwowano je w przestrzeni między błonami otoczki jądrowej. W cytoplazmie precypitaty występowały w mitochondriach, pęcherzykach i cysternach siateczki śródplazmatycznej gładkiej, strukturach aparatu Golgiego oraz w cytoplazmie podstawowej. Zawartość precypitatów w komórkach glejowych, komórkach środbłonka oraz fibrocytach była znacznie mniejsza niż w pinealocytach.

2

Proton and calcium ion transport across lipid membranes modified with LHCII complex

100%

Iwaszko E. , Wardak A. , Krupa Z. , Gruszecki W. I.

Polish Journal of Natural Sciences. Supplement

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2003

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tom 01

3

Investigation of quartz flotation from decarburized vanadium bearing coal

86%

Ren L. , Zhang Y. , Bian Y. , Liu X. , Liu C.

Physicochemical Problems of Mineral Processing

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2015

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tom Vol. 51, iss. 2

755--767

EN

Ether diamine (Fm 2835-2L) was used as a collector for flotation of quartz. It allows flotation of quartz from mica and calcite. The adsorption mechanism of Fm 2835-2L on quartz was investigated by flotation tests, zeta-potential measurements and infra-red (FTIR) spectra measurements. Results show that Fm 2835-2L adsorbs on the quartz surface in physical adsorption with no new products, changing its zeta potentials, and increasing its hydrophobicity. The effect of calcium ions on flotation of quartz was investigated by flotation tests and zeta-potential measurements. Results show that under neutral or weakly acidic conditions calcium cation can adsorb onto the surfaces of quartz, increase the zeta potential of quartz particles, which in turn causes weaker aggregation of quartz particles and lower flotation recovery of quartz. Under the alkaline conditions the hydrolytic components of calcium are also adsorbed on the quartz surface and increase the zeta potential of quartz particles, which causes stronger aggregation of quartz particles and higher flotation recovery of quartz. However, the hydrolytic components such as CaOH+, Ca(OH)2(aq) and Ca(OH)2(s) were not formed in significant amounts in the best flotation tests.

4

Role of dissolved mineral species in quartz flotation and siderite solubility simulation

86%

Luo X. , Wang Y. , Ma M. , Song S. , Zhang Y. , Deng J. , Liu J.

Physicochemical Problems of Mineral Processing

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2017

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tom Vol. 53, iss. 2

1241--1254

EN

Quartz is, in most cases, the major gangue mineral found in the iron ores. Although it can be activated by calcium at strong alkaline pH, quartz nevertheless, reports to the concentrate with Fe when the iron ores contain siderite. It causes a poor concentrate grade and separation between quartz and iron minerals. The effect of siderite on reverse anionic flotation of quartz from hematite was studied in our previous investigations. In this work, the effect of siderite dissolution on the quartz recovery in the froth product and the effect of pH, ions and temperature on siderite dissolution were investigated. Microflotation, PHREEQC simulation, solution chemistry calculation and Fourier transform infrared spectroscopy (FTIR) measurements were conducted. It was observed that the dissolved species of siderite exhibited negative impact on quartz flotation. This influence became weak to some extent by either stripping the dissolved species or shortening dissolution time. Siderite was easily dissolved in the presence of calcium ion under strong alkaline conditions and its solubility increased with increasing the calcium ion concentrate and temperature. When the calcium ion was added as an activator of quartz under strong alkaline conditions (pH>9.96), calcium existed mainly in the CaCO3 precipitation form according to the solubility rule in the presence of siderite. This form could adsorb onto quartz surfaces and further the chemical reaction between starch and quartz was monitored by FTIR measurements. This study provides a further supplement for previous study. A potential strategy is suggested that finding a collector used at low temperature or flotation under neutral (or weak alkaline) medium is helpful to the reverse flotation of iron ores containing siderite.

5

Stability of reconstituted casein systems against calcium ions, high temperature and ethanol

86%

Minkiewicz P. , Dziuba J. , Darewicz M. , Mioduszewska H.

Polish Journal of Natural Sciences

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2002

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tom 10

6

Calcium in pollen-pistil interaction in Petunia hybrida Hort. III. Localization of Ca2 ions and Ca2-ATPase in pollinated pistil

86%

Bednarska E. , Butowt R.

Folia Histochemica et Cytobiologica

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1995

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tom 33

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nr 2

7

The effect of flordimex and calcium ions on the metabolism of carotenoids in seedling of Triticale var. Grado

86%

Sykut A.

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tom 03

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nr 3-4

8

Calcium in pollen-pistil interaction in Petunia hybrida Hort. I. Localization of Ca2 ions in mature pollen grain using pyroantimonate and autoradiographic methods

86%

Bednarska E. , Butowt R.

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nr 4

9

Influence of amphiphilic anionic and cationic mixture on calcium ion desorption from lecithin liposomes. II. Computer simulation

86%

Kubica K. , Fogt A. , Kuczera J.

Polish Journal of Environmental Studies

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1994

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tom 03

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nr 4

EN

The cellular automaton method was used to simulate the process of ion desorption from the surface of lipid membranes modified with a mixture of cationic and anionic amphiphile molecules. Three models were devised to analyze the influence of anionic long-chain and cationic long-chain compounds, and a mixture of anionic short chain and cationic long chain compounds on bipositive ion desorption. The obtained results are compared with experimental results. These models show the significance of some hypotheses on the role of temporal complexes of the alkylsulphonate anion and calcium ion, of readsorption of calcium ions, and of different methods of molecular aggregation on the kinetics of calcium desorption.

10

Protective effect of Ca2plus ions on wall polysaccharides of Scenedesmus obliquus [Turp.] Kutz. cells treated with heavy metals

86%

Adam M. S. , Abdel-Basset R. , Issa A. A.

Acta Hydrobiologica

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1997

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tom 39

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nr 3-4

EN

S. obliquus cultures were subjected to various heavy metals (Cd, Co, Ni and Mn) in the presence or absence of calcium. Ca2+ increased the cell number (unicells or coenobia). Amounts of cell wall polysaccharides and soluble sugars were increased by the heavy metals used and decreased when Ca2+ was added, this perhaps being due to or resulting from inhibited cell division which did not allow the wall components to decrease by being distributed among daughter cells.

PL

Kultury S. obliquus poddano działaniu różnych metali ciężkich (Cd, Co, Ni i Mn) w obecności lub przy braku wapnia. Obecność Ca2+ sprzyjała zwiększaniu ilości pojedynczych komórek i cenobii. Metale ciężkie powodowały wzrost zawartości polisacharydów ściany komórkowej i cukrów rozpuszczalnych, natomiast dodanie Ca2+ wywoływało zmniejszanie ich ilości. Prawdopodobnie przyczyną tego zjawiska była inhibicja podziałów, co nie pozwalało na zmniejszenie ilości tych składników poprzez rozdział między komórki potomne.

11

Interaction of amphiphiles with model lipid membranes by 1H-NMR

86%

Rozycka-Roszak B. , Walkowiak U.

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1994

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tom 12

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nr 2

12

Distribution of calcified concretions and calcium ions in the pig pineal gland

86%

Lewczuk B. , Przybylska B. , Wyrzykowski Z.

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nr 4

13

The effect of simultaneous application of chlorocholine chloride [CCC] and calcium ions on accumulation of pectic substances fraction in the seedlings of winter wheat

86%

Szynal J.

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tom 03

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nr 3-4

14

Ca2 ions mediate the photophobic response in Blepharisma and Stentor

86%

Fabczak S. , Fabczak H. , Song P. S.

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nr 2

15

Calcium in pollen-pistil interaction in Petunia hybrida Hort. II. Localization of Ca2 ions and Ca2 -ATPase in unpollinated pistil

86%

Bednarska E. , Butowt R.

Folia Histochemica et Cytobiologica

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1995

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tom 33

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nr 1

16

Is practical salinity conservative in the Baltic Sea?

72%

Feistel R. , Weinreben S.

Oceanologia

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2008

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tom 50

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nr 1

73-82

EN

The conductivity-salinity conversion algorithm used for oceanographic measurements of Practical Salinity on the PSS-78 scale is designed for IAPSO Standard Seawater. The application of this formula to a given sample of non-standard seawater does not necessarily result in a constant salinity value when the sample’s conductivity is measured at different temperatures.We have experimentally studied the magnitude of this non-conservative effect of Practical Salinity using a sample of Baltic seawater possessing a density anomaly of about 50 g m−3. The apparent change of salinity observed is at the limit of experimental uncertainty and is not significantly different from the drift of Standard Seawater, which was measured for comparison.

17

Kinetics of calcium ion concentration accompanying signal transduction in neutrophils from children with increased susceptibility to infections

72%

Jakubczak B. , Wasik M. , Popko K. , Demkow U.

Journal of Physiology and Pharmacology. Supplement

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2006

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tom 57

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nr 4

131-137

EN

Increased susceptibility to infections can be a consequence of altered function of immune cells including neutrophils. The goal of the study was to evaluate the process of neutrophil activation via Ca2+-mediated signal. The study was performed on isolated peripheral blood neutrophils obtained from 41 children with recurrent infections (21 girls, 20 boys) 3-10 years old with more than five episodes of respiratory tract infection (RI) per year and from a control group of 30 healthy children age and sex matched, free from allergic, immune and hematological disorders. Neutrophils were activated by bacterial peptide fMLP, opsonized zymosan (OZ), and phorbol myristat acetate (PMA). The kinetics of the intracellular Ca2+ concentration i[Ca2+] was assessed by flow cytometry (Coulter Epics XL) with the use of Fluo3 and Fura Red fluorescent dyes. Data were collected in histograms displaying Fluo3 fluorescence vs. time and Fura Red fluorescence vs. time and the mean channels of fluorescence intensity were used for calculations. fMLP and OZ-induced Ca2+ mobilization lasted shorter in the RI group (P<0.05). The peak influx of free Ca2+ and i[Ca2+] in the resting state after stimulation with fMLP were lower in the patients (P<0.05). In the RI group stimulation with OZ was delayed compared with that in the control group (P<0.01). In response to PMA, i[Ca2+] decreased faster. The kinetic slopes of i[Ca2+] in both groups examined differed statistically at all points measured. A decrease in i[Ca2+] after PMA stimulation was greater (P<0.01) and lasted longer in the RI group. We conclude that increased sensitivity to infections in RI children may be related to the disturbance in neutrophil activation that is mediated by changes in i[Ca2+] with the subsequent production of free oxygen radicals. Such a disturbance may be inheritable or secondary to infection and antibiotic therapy.

18

The influence of selenium on the accumulation of K and Ca ions in rape seedlings subjected to cadmium stress

72%

Ploskonka J. , Rudolphi-Skorska E. , Sieprawska A.

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tom 545

EN

The aim of the experiment was to study the effects of selenium ions on the changes in membrane permeability for K and Ca in the leaves of rape during cadmium stress. The of stress level was determined by changes in the mass increment and lipid peroxidation (MDA concentration) in 3-week-old seedlings cultured in vitro on Murashige and Skoog [1962] medium (control) and on medium containing 600 µМ CdCl2. Selenium was added at the concentration of 2 µМ (Na2SeO4) to the control and medium containing cadmium ions. The level of K and Ca was determined with ionoselective electrodes after one hour of shaking leaf discs (membrane permeability) and heating to 100°C (total ion content). Cadmium present in the nutrient medium inhibited the mass increment and increased MDA concentration, and significantly decreased membrane permeability for K and Ca. In the mixtures of cadmium and selenium, selenium ions partially reduced the effects of the stress-inducing cadmium action on the studied physiological parameters and membrane permeability to the studied ions. The observed protective effect of selenium can be the result of the effect of this substance on both the activity of ion channels and peroxidation of membrane lipids.

PL

Celem przeprowadzonych eksperymentów było sprawdzenie, protekcyjnego działania jonów selenu na zmiany w przepuszczalności błon komórkowych trzytygodniowych siewek rzepaku dla jonów K i Ca podczas stresu kadmowego. Poziom stresu określano poprzez zmiany w przyroście masy oraz peroksydacji lipidów (stężenie MDA) siewek hodowanych w warunkach in vitro na pożywkach wg Murashige i Skooga [1962] (kontrola) oraz zawierających 600 µМ CdCl2. Selen podawano w stężeniu 2 µM (Na2SeO4) do pożywek kontroli oraz zawierających jony kadmu. Poziom jonów K i Ca oznaczano przy pomocy elektrod jonoselektywnych po 1 godzinie wytrząsania krążków wyciętych z liści (przepuszczalność membran) oraz po ogrzaniu do temperatury 100°C (całkowita zawartość jonów). Kadm obecny w pożywce powodował zahamowanie przyrostu masy i wzrost stężenia MDA, znacznie obniżał przepuszczalność błon dla jonów K i Ca. W mieszaninach kadmu z selenem, jony selenu powodowały częściową redukcje zarówno stresogennego działania kadmu na badane parametry fizjologiczne jak również na przepuszczalność błon dla badanych jonów. Obserwowany ochronny efekt selenu może być związany z wpływem tej substancji zarówno na aktywność kanałów jonowych, jak i peroksydacji lipidów błonowych.

19

Biochemistry of magnesium

72%

Pasternak K. , Kocot J. , Horecka A.

Journal of Elementology

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2010

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tom 15

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nr 3

601-616

EN

Magnesium is essential for biochemical functions of cells. Since Mg2+ has a relatively low ionic radius in proportion to the size of the nucleus (0.86 versus 1.14 f A for Ca2+), it shows exceptional biochemical activity. Due to its physicochemical properties, intracellular magnesium can bind to the nucleus, ribosomes, cell membranes or macromolecules occurring in the cell’s cytosol. It is indispensable for the nucleus to function as a whole and for the maintenance of physical stability as well as aggregation of rybosomes into polysomes able to initiate protein synthesis. Mg2+ can also act as a cofactor for ribonucleic acid enzymes (ribozymes) capable of specifically recognizing and cleaving the target mRNA. As an essential cofactor in NER, BER, MMR processes, Mg2+ is required for the removal of DNA damage. An activator of over 300 different enzymes, magnesium participates in many metabolic processes, such as glycolysis, Krebs cycle, β-oxidation or ion transport across cell membranes. Mg2+ plays a key role in the regulation of functions of mitochondria, including the control of their volume, composition of ions and ATP production.

PL

Magnez jest składnikiem niezbędnym dla zasadniczych funkcji biochemicznych komórki. Ponieważ Mg2+ ma relatywnie mały promień w stosunku do wymiarów jądra (0.86 i 1.14 A odpowiednio dla Mg2+ i Ca2+), wykazuje dużą aktywność biochemiczną. Dzięki właściwościom fizykochemicznym śródkomórkowy Mg2+ może wiązać się z jądrem komórkowym, rybosomami, błonami komórkowymi oraz makromolekułami cytosolu komórki. Magnez jest niezbędny dla funkcjonowania jądra komórkowego jako całości oraz utrzymania fizycznej stabilności i agregacji rybosomów do polisomów zdolnych do biosyntezy białka. Odgrywa on również rolą kofaktora katalitycznych cząsteczek RNA (rybozymów), odpowiedzialnych za specyficzne rozpoznawanie i fragmentację docelowego mRNA. Jako kofaktor w procesach: NER, BER, MMR, przyczynia się do usuwania uszkodzeń DNA. Magnez, będąc aktywatorem ponad 300 różnych enzymów, uczestniczy w przebiegu wielu szlaków metabolicznych, takich jak glikoliza, cykl Krebsa, β-oksydacja czy transport jonów poprzez błony komórkowe. Odgrywa on ponadto bardzo ważną rolę w regulowaniu funkcji mitochondriów, łącznie z regulacją ich wielkości, kompozycją jonów, a także bioenergetyką i regulacją produkcji ATP.

20

The influence of insulin on calcium ion concentration during transduction of signals into neutrophils

72%

Demkow U. , Winklewski P. , Potapinska O. , Popko K. , Lipinska A. , Wasik M.

Journal of Physiology and Pharmacology. Supplement

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2008

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tom 59

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nr 6

219-229