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Malnutrition of pregnant women can slow down dental tissue development in offspring, cause growth of tooth decay and other disruptions, associated with changes amount of biogenic elements (BE), which are received into child in the womb body. The aim of this study-determination of the BE in the enamel and blood serum of mother rats, who had unbalanced nutrition with excess or lack of nutrients during the pregnancy. The content of Ca, Mg, Cu, Fe, P and Zn was studied in 129 species 1- and 2-month offspring. Reduction of BE in the enamel and blood serum mote often exist and more raised in pups, whose prenatal development took place under a shortage of nutrients. The direction of content changes of BE in pups and their degree of intensity are not identical in the enamel and blood serum. Certain pattern was identified between the content in the enamel and blood serum only two elements- Ca (direct correlation) and Fe (negative correlation). Irregularities of BE imbalance in the enamel during mothers' unbalanced nutrition at the time of pregnancy threaten by negative effects in terms of growth various pathological conditions and diseases of dentition apparatus their offspring in later life.

The influence of two-week daily microinjections of ZnCl2 into the rostral region of neostriatum on the locomotor behavior of Wistar rats in chronic experiments was studied. The 1-mcg dose of ZnCl2 decreased spontaneous locomotor activity in the "open field" and, beginning with the 5th day of microinjections, inhibited a shuttle-box conditioned avoidance reflex. The reflex recovered only in the first week after the injection withdrawal. The 0.1-mcg dose of ZnCl2 to a lesser extent affected the parameters of conditioned avoidance, whereas the level of spontaneous locomotor activity in this group of animals increased. The observed changes in rat behavior may be associated with the concentration-dependent influence of zinc ions on the ion channels in the membranes of neostriatum neurons, including glutamate activated. The possibility to control the activity of ion channels in a chronic behavioral experiment by zinc ion concentration is discussed.

The effect of Ca2+ on morphophysiological parameters of calluses of wheat Triticum aestovum L., the level of active oxygen species, and the activity of oxalate oxidase, peroxidase, and catalase is investigated in the case of infestation with the fungus Triticum aestivum causing ball smut. The concentration of O2-, H2O2, and activity of oxidoreductases (oxalate oxidase, peroxidase, and catalase) depends on the content of Ca2+ ions in the culture medium of calluses. The increase in the concentration of Ca2+ ions in the culture medium led to higher structuring of calluses, induction of activity of oxalate oxidase and of some forms of peroxidase, and to accumulation of active oxygen species. These changes contributed to inhibition of development of the fungus. Discovery of such dependence agrees with the role of calcium as the intermediary in biochemical reactions related to the formation of the protective response of plant cells in case of infestation.

It has been shown for the first time by the method of isothermal calorimetry of titration that the N-terminal amino group of the beta-amyloid protein, which plays a key role in the binding of copper ion, ceases to form the proper coordinating bond as a result of the isomerization of aspartate-7.

The level of resistance to antibiotics of various chemical structure in actinobacteria of the genus Streptomyces is shown to be regulated by Ca2+ ions. The inhibitors of Ca2+/calmodulin and Ca2+/phospholipid-dependent serine/threonine protein kinases (STPK) are found to reduce antibiotic resistance of actinobacteria. The effect of Ca2+ -dependent phosphorylation on the activity of the enzymatic aminoglycoside phosphotransferase system protecting actinobacteria from aminoglycoside antibiotics was studied. It is shown that inhibitors of Ca2+/calmodulin and Ca2+/phospholipid-dependent STPK reduced the Ca2+ -induced kanamycin resistance in Streptomyces lividans cells transformed by a hybrid plasmid which contained the aminoglycoside phosphotransferase VIII (APHVIII) gene. In S. coelicolor A3(2) cells, the protein kinase PK25 responsible for APHVIII phosphorylation in vitro was identified. It is suggested that STPK play a major role in the regulation of antibiotic resistance in actinobacteria.

Magnesium is one of the major cations of biological systems. It plays an essential role in many cell processes. The importance of magnesium underlines its maintenance under the steady conditions according to the metabolic state of the cell. In the present review mechanisms of magnesium homeostasis, that have been intensively investigated during last decades using both pathophysiological and molecular genetic approaches, are considered. Disorders of magnesium homeostasis resulted in development of magnesium-deficient conditions, which are commonly found in various diseases (diabetes mellitus, cardiovascular diseases, chronic fatigue, alcoholism, psychiatric and neurologic diseases, etc.), stress condition and therapy with some kind of drugs. Special attention is paid to familial hypomagnesemias caused by genetic defects of magnesium transport systems. Overview of clinical and biochemical characteristics of twelve familial disorders is given and mechanisms of inherited magnesium homeostasis disorders as well as nine identified and mapped genes responsible for their development are considered. These genes encode subunits of ionic channels, co-transporters, modulators of transport systems and receptors controlling either intestinal absorption or renal reabsorption of magnesium. Recent advances in mechanisms of magnesium homeostasis will lead to insights in diagnostics, preventive medicine and treatment of magnesium-deficient conditions.

The release of divalent cations (Ca2+ and Sr2+) from rat liver mitochondria after membrane depolarization with protonophore (carbonyl cyanide m-chlorophenyl hydrazone, CCCP), sodium azide and K(+)-ionophore (valinomycin) was studied. It is stated that membrane depolarization itself is not sufficient for cations release from mitochondrial matrix (provided that mitochondrial permeability transition pore is blocked by cyclosporin A). Complete delivering of divalent cations is observed only after protonophore (CCCP) addition to suspension of deenergized mitochondria. The data show that membrane permeabilisation to hydrogen ions (H+) is necessary for complete cation release from the mitochondrial matrix. The enhancement in K(+)-conductivity of mitochondrial membrane (by valinomycin), on the contrary, is not able to provide complete delivering of cations from mitochondria. It is shown that quantity of divalent metal cation released from mitochondria (depolarized and permeabilized for K+ as well) is proportional to the concentration of protonophore (but not K(+)-ionophore) introduced in the incubation medium. The data obtained lead to the conclusion that H(+)-permeabilization of the mitochondrial membrane is necessary for the complete release of Ca2+ and Sr2+ from mitochondria after membrane depolarization. The possible mechanism of divalent metal cations release from deenergized mitochondria is discussed.

A modified nucleotide on the 3'-side of the anticodon loop of tRNA is one of the most important structure element regulating codon-anticodone interaction on the ribosome owing to the stacking interaction with the stack of codon-anticodon bases. The presence and identity (pyrimidine, purine or modified purine) of this nucleotide has an essential influence on the energy of the stacking interaction on A- and P-sites of the ribosome. There is a significant influence of the 37-modification by itself on the P-site, whereas there is no such one on the A-site of the ribosome. Comparison of binding enthalpies of tRNA interactions on the P- or A-site of the ribosome with the binding enthalpies of the complex of two tRNAs with the complementary anticodones suggests that the ribosome by itself significantly endows in the thermodynamics of codon-anticodon complex formation. It happens by additional ribosomal interactions with the molecule of tRNA or indirectly by the stabilization of codon-anticodon conformation. In addition to the stacking, tRNA binding in the A and P sites is futher stabilized by the interactions involving some magnesium ions. The number of them involved in those interactions strongly depends on the nucleotide identity in the 37-position of tRNA anticodon loop.

Rat liver oxidative stress caused by toxic hepatitis is accompanied by increased activity of glucose-6-phospate dehydrogenase (EC 1.1.1.4.9; G6PDG). Electrophoretically homogenous G6PDG preparations purified from livers control rats and animals with hepatitis had specific activity of 4.13 and 6.54 EU, respectively. Fe2+ and Cu2+ ions showed non-competetive type inhibition of G6PDG at normal and under pathological condition, whereas Ca2+ activated G6PDG. Hydrogen peroxide exhibited mixed type inhibition of G6PD (K(i) 0.36 mM and 0.95 mM at norm and experimental toxic hepatitis, respectively). The participation of oxidised and reduced glutathione in G6PDG activity regulation has been shown.

We studied the biosynthesis of Bacillus intermedius glutamyl endopeptidase in the recombinant Bacillus subtilis strain AJ73 delta58.21 during the stationary growth phase. We optimized the composition of the culture medium to favor effective enzyme production during the stationary growth phase, and found that the nutritional requirements for glutamyl endopeptidase synthesis were different in the stationary phase and growth retardation phase. Proteinase accumulation was activated by complex organic substrates (casein and gelatin). During final stages of the culture growth, the enzyme production was stimulated by Ca2+, Mn2+, and Co2+ and inhibited by Zn2+, Fe2+, and Cu2+. The synthesis of glutamyl endopeptidase in the late stationary phase was not inhibited by glucose, unlike that in the trophophase during proliferation. We conclude that the regulatory mechanisms of proteinase synthesis during vegetative growth and sporulation are different.

The effect of metal cations on copper-catalyzed lipid peroxidation (LPO) of low density lipoproteins (LDL) was examined. The presence of metal cations in the incubation media containing LDL (0.8 mg protein/ml) and CuSO4 (0-80 microM) influenced on LPO of LDL as evident by the measurement of TBARS. With the concentrations of CuSO4 less than 10 microM, the metal cations caused an increase in LDL peroxidation. Zn2+ appeared to be the most effective inductor, Mn2+ was less effective, and the influence of Ca2+ and Mg2+ was insignificant. With greater CuSO4 concentrations Mg2+ showed no effect on TBARS formation in LDL while the addition of other nontransition metal cations to the incubation mixture led to the inhibition of LDL peroxidation. The capacity for inhibition decreased in the row Mn2+ > Zn2+ > Ca2+ > Mg2+. The possible mechanism explaining these results may be in the competition of metal ions for copper binding sites on LDL. Our results allow to suggest the existence of two types of copper binding sites on LDL, tight-binding sites which are non-effective in LPO and effective weak-binding sites.

Presence of Ca2+, Mg(2+)-dependent endonuclease activity was found in dog liver cell nuclei. Specific characteristics of chromatin autolysis were also studied in liver cell nuclei after 2-4 hrs long arterial hypotension as compared with that within the later restoration period 1-3 months. The rate of DNA acid-soluble fraction accumulation correlated directly with the arterial hypotension duration. Quantitative evaluation of the liver tissue Ca2+, Mg(2+)-dependent endonuclease activity was undertaken under conditions of hemorrhagic shock. The enzymatic activity was not normalized both after death and in the postresuscitation period. Analysis of the chromatin autolysis and of alterations in the enzymatic activity during postresuscitation period enabled to suggest that the isozyme spectrum of Ca2+, Mg(2+)-dependent endonuclease was altered.

The dependence of Ca2+ transport in synaptosomes along the channels formed by alpha-latrotoxin on [Ca2+]in and the feasibility of transport along these channels of other bivalent cations were studied. It was found that the concentration dependence of Ca2+ influx is nonlinear and is described by the Michaelis-Menten kinetics (Km = 1.07 +/- 0.19 mM). Mg2+, Ba2+, Sr2+, Mn2+ and Co2+ competitively inhibited the Ca2+ influx via latrotoxin channels. Studies with the use of the fluorescent Ca2+ probes, Quin-2 and Fura-2, revealed that these cations can also penetrate inside synaptosomes via latrotoxin channels. The bivalent cation influx via latrotoxin channels caused a decrease of the membrane potential of synaptosomes. The similarity of properties of latrotoxin and endogenous Ca2+ channels is discussed.

The surface charge density (sigma'0 and the constant of Ca2+ binding with the charged surface groups of the outer side of the membrane (KCa) are calculated on the basis of experimentally determined values of the current-voltage characteristic shifts for calcium currents in the membrane of rat spinal ganglia neurons. The obtained values are as follows: sigma'0 = 0.15 +/- 0.05 e/nm2 and KCa = 70 +/- 10 1/ml. The energy profile of the calcium channel in the membrane of investigated neurons was calculated for Ca2+, Ba2+ Cd2+ Mn2+ Co2+ ions and verapamil using a three-barrier model. It is shown that the value of calcium current is determined mainly by the potential hole depth which corresponds to the outer binding centre of the calcium channel. On the basis of the data obtained a conclusion is made that the outer binding centre contains only one carboxylic group.

The effect of lysine-rich histone on mitochondria was studied with respect to the cation transport and proton uptake across the membrane. Histone does not affect Ca2+ uptake or level in mitochondria. It extrudes Mg2+ by 30% with the utilization of substrates; in the presence of rotenone extrusion drops to about 18%. Dinitrophenol and ADP prevent the effect of histone. Mg2+ uptake is inhibited by 12% by histone. K+ extrusion by histone (by 50%) which depends on the oxidation of substrates, is enhanced by phosphate, and Mg2+ decreases (by 50%) the K+ extrusion. Histone prevents to some extent extrusion of K+ by Ca2+. Histone does not affect Na+ level in mitochondria, it blocks (by 50%) Na+ uptake in the presence of gramicidin, probably by forming a gramicidin-histone complex. Histone blocks proton uptake by mitochondria incubated in the presence of valinomycin or DNP. In the presence of DNP valinomycin-induced H+ uptake is not affected by histone. H+ uptake induced by nigericin is not affected by histone as well.

As it has been demonstrated in the giant (Retzius') neuron of the leech (Hirudo medicinalis), at the synaptic activation for 5 sec. and 10 min., ultrastructural changes in the neuron are accompanied with an increasing number of Ca++ ions in hyaloplasm, mitochondria and cytosomes. After activation, the ultrastructural changes increase, and the number of Ca++ ions returns to the initial level. A suggestion is made on a trigger function of Ca++ ions when the neuronal ultrastructure changes under conditions of the synaptic activation.

ESR study was carried out of the interaction between Zn2+, Cu2+, Ca2+, Mg2+ ions and human serum albumin (HSA) in the presence of Mn2+ ions which depends on pH. Competitive binding of these ions with "manganese-binding" sites of albumin was shown to depend on pH. An analysis of concentration dependence of binding these ions with human serum albumin confirmed earlier supposition about the nature of the binding sites of Mn2+ ions with HSA.

The interaction of DNA with divalent metal ions: Ba2+, Mg2+, Mn2+, Ni2+, Cu2+ in solutions at different ionic strengths mu was investigated. The combination of following methods: flow birefringence, viscometry, UV-spectroscopy and circular dichroism made possible to follow the state of the secondary and tertiary structure of the DNA molecule during its interaction with ions. The presence of divalent ions in solution affects the hydrodynamic properties of DNA only at low mu. At high mu the difference in the action of mono- and divalent ions disappears. The persistence length of DNA does not change during the experiment. It is shown that the Mg2+ and Ba2+ ions interact only with phosphate groups of DNA but Mn2+, Ni2+, Cu2+ ions interact also with the nitrogen bases of the macromolecule.

Chromatography of a mixture of phospholipid and Ca-dependent ATPase of sarcoplasmic reticulum solubilized with choleate in a column with anionite results in proteolyposome formation. It was shown that dilution of ATPase with phospholipids makes it possible to reduce the concentration of ATPase in the membrane. Using the bifunctional reagent difluorodinitrobenzene it was demonstrated that reduction of the ATPase concentration in the membrane leads to the dissociation of the enzyme to monomers. It was disclosed that the monomeric form of ATPase is capable of active Ca2+ transport.

Ca2+-binding activity of heart mitochondria does not change with aging of rats. The results are discussed in terms of experimental mitochondrial involvement in the control of myocardial contractility with regard to the reported data on the increased period of myocardial relaxation and diminution of the myocardium mitochondrial content during aging.

Effect of the lipid peroxidation (LP) on the Ca2+-transport and the effect of different Ca2+-concentrations on the LP activation were studied in microsomes and mitochondria of the heart. A slight accumulation of LP-products in the microsomal fraction results in a complete inhibition of the membrane calcium-transport activity. Preliminary administration of antioxidants (4-methyl 2,6-ditretbutylphenol and alpha-tocopherol) prevents both the accumulation of LP-products and damage of the Ca2+-transport system. Calcium at 10(-6) M to 5 X 10(-5) M concentrations stimulates LP and while being increased to 2 X 10(-3) M it inhibits LP. The data obtained evidence an interrelation between alterations of the Ca2+-concentrations and LP activation in cardiomyocytes.

The intracellular perfusion technique rendered isolated neurons a convenient object for studying the Ca channels securing inflow of these ions across the membrane into the cell in excitation. Extensive research showed the Ca channels to pass the cations in the sequence Ba greater than Sr greater than Ca greater than Mg and bind these ions with the aid of a binding compound within the channel. Other cation (Co, Ni, Mn, Cd) which are too closely bound with this compound become competitive blocking agents for the channels. In absence of the bivalent cations in the extracellular space the Ca channels loose their selectivity and allow monovalent cations to pass, the reason for this transformation beeing a disruption between the bound Ca ions and the specific regulating compound within the Ca channels. The channels can exist in two states: conducting and nonconducting. The transition from one state to another is accompanied by an intramembrane transfer of charges ("the gate current"). The statistic kinetics of this transition can be described by means of a modified Hodgkin-Huxley equation. In prolonged depolarization the Ca channels become inactivated due to recurrent blocking effect of the Ca ions penetrating in the cell. Some types of the Ca channels, however, reveal a potential-dependent inactivation analogous to that of the sodium or potassium channels.