[A possible molecular mechanism of the narcotic action of noble gases].

A molecular mechanism of the narcotic action of noble gases is suggested, which is based on the fact that noble gas atoms change the orientation of water molecules absorbed on the surface of axon membrane. The resulting change in the transmembrane potential deteriorates the propagation of nerve pulse.

The polarization model in bacterial photosynthesis.

The widely accepted model of reaction center /RC/ functioning is proved to come into contradiction with some recent data. In particular, it cannot explain why only a minor part of electronic excitations (approximately 10%) escapes from excited RC special pairs back to antenna BChls. Therefore we believe that the model must be substantially modernized. In 1981 we developed a new model/1,2/. We suggested a femtosecond state to precede primary e-transfer reaction due to reorientation of water molecule dipole in the electric field of excited RC dimer. This mechanism is responsible for energy trapping before the primary e-transport occurs. During last years his mechanism got support from various experimental works. Now this polarization model claims to fit all reliable experimental data at least in bacterial photosynthesis.

Perfluorocarbon emulsions increase transfer of oxygen in plasma from erythrocyte to tissues.

The erythrocyte oxy- and deoxygenation kinetics and the influence of the perfluorocarbon emulsions (PFCE) on the blood were studied using the device modeling blood circulation in the organism. It was found that a small additive of PFCE changed the oxygen transport in the erythrocyte-plasma-tissues. The oxygen-carrying properties of erythrocytes of PFCE-blood system are differ from ones of pure blood.

[Diffusion of glucose through the erythrocyte membrane]. / Issledovanie diffuzii gliukozy cherez membranu éritrotsitov.

The change of volume of human erythrocytes due to diffusion of glucose through their membranes was investigated. The dependence of membrane glucose penetration on functional state of the cells was discovered.

[The erythrocyte as a physical system. The kinetics of transmembrane oxygen transport]. / Eritrotsit kak fizicheskaia sistema. Kinetika transmembrannogo perenosa kisloroda.

It is inferred from analysis of normal physiology data that erythrocyte membrane permeability for the oxygen in human organism must decrease at least 1000 times after oxygenation in the lungs. And the cell membranes of other tissues are also capable to change their permeability for the oxygen. The kinetics of blood oxygenation and deoxygenation is investigated in order to check this conclusion. Measurements of blood oxygenation kinetics together with oxygen tension in blood plasma allows to determine average value of membrane permeability decrease being equal 70 times. Biological expediency of fluctuation of the erythrocyte membrane permeability is discussed. A method of determination of optical oxymeters calibration and hemoglobin-oxygen equilibrium curve for the blood is proposed. It does not require the oxygen equilibrium between the blood plasma and the erythrocyte cytoplasm and uses only readings of a calibrated oxymeter. Variation of non-equilibrial state of the erythrocyte during the oxygen saturation is considered as the cause of the membrane permeability fluctuation. Erythrocyte parameters, such as its volume, substances concentration, transmembrane potential, are shown to depend on the amount of the substances not penetrating through the membrane and on osmotic pressure. A hypothesis of the transmembrane potential influence on the membrane permeability is proposed. The external electric field is shown experimentally to accelerate the blood deoxygenation.

[The kinetics of oxygen transport by the blood]. / Kinetika perenosa kisloroda krov'iu.

A method for calculation of oxygen metabolism kinetics in vivo for different blood pH and for different inhaled air pressure is proposed. It is based on joint solution of equations of oxygen balance in lungs and in capillaries of oxygen-consuming tissues. All calculations were carried out within the physiological range of the above parameters. The value of maximum physical load was estimated for each set of the parameters. This load was evaluated in respect to the maximal oxygen consumption possible under conditions selected. Only data borrowed from normal physiology were used in calculations. It was shown that oxyhemoglobin dissociation curve shifts (for example, caused by blood pH deviation from its norm) does not have substantial influence on the organism ability to produce work, on its supplement with the oxygen, and can not cause pathologies at acidosis and alkalosis. This new result was obtained due to adoption of strict equality of the oxygen flows absorbed by blood in the lungs and of the oxygen given back by the blood in capillaries of the oxygen-consuming tissues.

[The effect of an inhibitor on the dependence of single-enzyme reaction rate on pH]. / Vliianie ingibitora na zavisimost' skorosti odnofermentnoi reaktsii ot pH.

The enzyme reaction speed dependence on pH was calculated. It was shown that two speed maxima and higher pH sensitivity should be in reaction with inhibitor.

[The autoregulation of intracellular oxygen tension and the modification of cellular radiosensitivity. The development of an adaptation hypothesis]. / Avtoreguliatsiia vnutrikletochnogo napriazheniia kisloroda i modifikatsiia radiochuvstvitel'nosti kletok. Razvitie adaptatsionnoi gipotezy.

A hypothesis is reported postulating that the range within which the intracellular oxygen content varies with changes in the external oxygenation conditions is responsible for the oxygen-dependent radiosensitivity modification that may be controlled by the diffusion resistance of a cytoplasmic membrane. The adaptation mechanism of intracellular Po2 autoregulation is involved when drastic changes in the oxygen content of the environment occur. As the oxygen content decreases this mechanism provides maximal values of the intracellular Po2 required for optimizing cell viability; the increased oxygen content prevents cells from oxygen intoxication.

[The effect of decreasing erythrocyte membrane permeability for oxygen during oxygenation]. / Effekt umen'sheniia pronitsaemosti membran éritrotsitov dlia kisloroda v protsesse oksigenatsii.

It was shown that erythrocyte membranes permeability for oxygen decreases at least a few tens of times during oxygenation.

[Calibration of oxygen meters and determination of the curve for hemoglobin dissociation by kinetics of oxygenation and deoxygenation of the blood]. / Kalibrovka oksigenometrov i nakhozhdenie krivoi dissotsiatsii gemoglobina po kinetike oksigenatsii i deoksigenatsii krovi.

A method to determine optical oxygenometers calibration and hemoglobin--oxygen equilibrium curve for the undamaged blood is described. This method does not require the oxygen equilibrium between the blood plasma and erythrocyte cytoplasm and uses only readings of the oxygenometer calibrated.

[Dynamics of erythrocyte oxygenation in vitro]. / Dinamika oksigenatsii éritrotsitov in vitro.

The process of blood oxygenation in vitro was described theoretically. It was established that the dynamics of the oxygenation degree of different blood samples can be obtained from the certain universal time function by a change of the time scale. A special device was created for experimental investigation of oxygenation dynamics. The experimental data are in agreement with the theory.

[Means of optimizing light energy conversion in the primary stages of photosynthesis. II. Optimization of the structure of an uniform photosynthetic unit lattice]. / Puti optimizatsii preobrazovaniia svetovoi énergii v pervichnykh aktakh fotosinteza. II. Optimizatsiia stroeniia reshetki odnorodnoi fotosinteticheskoi edinitsy.

The possibility of optimization of the structure of a model photosynthetic unit lattice is analysed. The efficiency of the photosynthetic unit operation is evaluated from the time of excitation energy trapping by reaction centers. The calculations assume a Förster inductive resonance mechanism for energy transfer within light--harvesting antenna and pairwise dipolar interactions. We use the probability matrix method which is adapted to excitation trapping time (but not to excitation jumps number) calculation. It is shown that the specific anisotropy of the distances between antenna molecules (which is in principle possible due to the diskshaped form of chlorophyll molecules) in combination with the optimal spatial arrangement of reaction centers as "well regulated clusters" allows to decrease the time of excitation energy trapping by over an order of magnitude. The requirements for optimization of the structure of a macroscopic photosynthetic unit lattice and the consequences following from them for the in vivo systems are formulated.

[Means of optimizing conversion of light energy in the primary stages of photosynthesis. I. The need for optimizing the structure of a photosynthetic unit and calculation of its efficiency]. / Puti optimizatsii preobrazovaniia svetovoi énergii v pervichnykh aktakh fotosinteza. I. Neobkhodimost' optimizatsii struktury fotosinteticheskoi edinitsy i rascheta ee éffektivnosti.

It is shown, that the photosynthetic unit structure is to be strongly optimized in vivo to operate with a 90% quantum yield of primary charge separation in reaction centers, which means that a macroscopic photosynthetic unit is neither uniform nor isotropic. Some requirements for optimization of photosynthetic unit structure are determined. The modified probability matrix method to simulate the excitation energy transfer in photosynthesis is proposed. The method is adapted to excitation trapping time (but not to excitation jumps number) calculation. The calculations assume a Förster inductive resonance mechanism for energy transfer within light-harvesting antenna and pairwise dipolar interactions.

[Factors of the optimization of the light-harvesting antenna structure of the photosynthetic unit]. / Faktory optimizatsii struktury svetosobiraiushchei antenny fotosinteticheskoi edinitsy.

The principles of model construction of pigment apparatus affecting the rate of energy trapping are analysed. The basic properties of the model system allowing optimization of this process are as follows: the spectral heterogeneity of light-harvesting pigment antenna; the proper mutual orientation of transition moment vectors of antenna molecules; the space arrangement of light-harvesting antenna molecules; the availability of "the focusing zone" of reaction centers, which is formed by the nearest to reaction centers antenna molecules.

[Model of water participation in stabilization of charges in primary photosynthesis events]. / Rolvody v stabilizatsii rasdelennykh zariadov v pervichnom akte fotosinteza.

A hypothesis is elaborated which advances a model of primary change separation in photosynthetic reaction centres. This model implicates two principal ideas: i) photoexcitation (or excitation migration from antenna chlorophyll) of reaction centre dimer (P700, P840, P870-P890) induces a charge transfer state with an electron from one molecule being transferred to another one (corresponding distance must be approximately greater than 6 A); ii) the above state is stabilized due to rapid (congruent to l psec) orientation of electric dipoles of nearest water molecules in the local field of dimmer transition moment. The quantitative energetic calculations confirm the consistence of the hypothesis with the literature data available and enables us to explain the molecular mechanisms of some primary events of photosynthesis.

[Analysis of the linear dichroism of reaction centers oriented in polyacrylamide gel]. / Analiz lineinogo dikhroizma reaktsionnykh tsentrov, orientirovannykh v poliakrilamidnom gele.

A model for orientation of rigid disc-shaped and rod-shaped macromolecules in polymer is analysed. Analytical expressions are given for the dependence of linear dichroism value on the angle between the transition dipole vector and the axis of the macromolecules, for certain deformation of the sample. The reaction centers from Rhodopseudomonas sphaeroides R-26 are oriented as rod-shaped particles. The angles between the long axis of the reaction center and transition dipoles for bacteriochlorophyll 31.8 +/- 2,4 degrees (870 nm), 42,3 +/- 0.9 degrees (796 nm), 68.0 +/- 0.6 degrees (600 nm) and for bacteriopheophytin 76.5 +/- 1.9 degrees (760 nm), 39.8 +/- 1.5 degrees (540 nm) are determined from absorption spectra.