[Comparative embryology and mammalian cloning].

A hypothesis has been advanced that logically combines "contradictory" facts concerning the early mammalian development and shows a natural relationship between the embryos developing from a fertilized ovum and from cells of the inner cell mass of blastocyst. When studying the theoretical questions of cloning, it is necessary to take into consideration the peculiarities of prenatal mammalian ontogenesis, which make themselves evident upon comparison with other animals. The absence of yolk in the mammalian ovum defines sharp differences in the early development between mammals and other Amniota. The whole asynchronic cleavage results in the formation of the morula followed by the blastocyst, which hatches from zona pellucida and is implanted into the uterus tissue. This fact allows us to consider the blastocyst as a mammalian larva, which is fed thanks to maternal organism. It is known that, in the body of a larva (blastocyst), a new embryo develops from some somatic cells. This process is known as a polyembryony, which is typical for the development of some parasitic insects. The polyembryony in turn is a variant of somatic embryogenesis, which is a form of asexual reproduction. Thus, two different embryos, "conceptus" and "embryo proper", have different origin: the first forms by the sexual way and the second, by the asexual. The investigation of the mechanisms of somatic embryogenesis in mammals will help us to find conditions necessary for the full reprograming of donor somatic nuclei and provide the successful development of reconstructed embryos.

[Cell engineering and genetic approaches to the development of models of human embryonic stem cells for studying genetic disorders].

A novel approach to the establishment of genetically modified human embryonic stem cell (hESC) lines has been developed, and it has been shown that mutant hESC may be derived from affected embryos after preimplantation genetic diagnosis screening for a particular single gene disorder. Here we provide the description of embryo and cell manipulation procedures, diagnostic lay out, analysis of the efficiency of embryo development and hESC establishment, as well as developments for hESC derivation in animal free conditions. The high efficiency of the approach (50%) is especially crucial in the work with rare and unique resources, such as genetically screened embryos necessary for the derivation of hESC lines representative of specific genetic diseases.

[Trabeculae and the intertrabelcular tissue during the contraction of the frog atrium at decreased temperatures and sodium ion concentrations in solution].

Data characterizing the kinetics of the contraction of trabeculae and the intertrabelcular tissue have been obtained. It has been concluded that trabeculae can act as conductors/transmitters of contraction across the myocardium and play a leading role in this process, while the functional role of the intertrabelcular tissue is secondary and more passive, and consists in the optimization and support of the contractile process.

[Individual consciousness].

The main modern concepts on the consciousness nature are considered. Together with the dualistic concepts, there exist concepts the adherents of which find it possible to get to know the origin of consciousness on the basis of natural science. A critical analysis of those concepts brings the author to the conclusion that they do not solve the main problem of individual consciousness: how subjective elements of consciousness arise in the brain as a result of objectively registered processes. The main reason of failures to solve said problem is considered by the author in the fact that the subjective categories of consciousness are not really subject to science. Nevertheless, it does not mean the dualism is to be inevitably accepted. In fact, the subjective categories arise in the limits of a life the area of which is substantially wider than that of science. An original information and physical hypothesis is being set up that provides for necessary premises and conditions enabling the origination of subjective categories of consciousness during the progressive natural evolution of living systems.

[Interaction of melittin with ion channels of excitable membranes].

The effect of the neurotoxin melittin on the activation of ion channels of excitable membrane, the plasmalemma of Characeae algae cells, isolated membrane patches of neurons of mollusc L. stagnalis and Vero cells was studied by the method of intracellular perfusion and the patch-clamp technique in inside-out configuration. It was shown that melittin disturbs the conductivity of plasmalemma and modifieds Ca(2+)-channels of plant membrane. The leakage current that appears by the action of melittin can be restored by substituting calmodulin for melittin. Melittin modifies K(+)-channels of animal cell membrane by disrupting the phospholipid matrix and forms conductive structures in the membrane by interacting with channel proteins, which is evidenced by the appearance of additional ion channels.

[Neuron-glial junction formation in cerebellum after electrical stimulation in presence of no-generating substance].

Molecular layer of frog (Rana temporaria) cerebellum was studied using light and electron microscope after electrical stimulation of parallel fibers in presence of NO-generating compound. Under these conditions, significant swelling of axonal terminals (boutons) of granular cells and astrocyte processes (AP) with a loss of cytoplasmic elements. However, along with the damaged structures, intact boutons were found with synaptic vesicles and APs containing glycogen granules. It is suggested that the remaining viable APs are capable of forming 1) protective glial "wrappings" around damaged synapses or boutons, and 2) neuron-glial junctions, that are formed due to transmission of synaptic vesicles through the damaged membrane of bouton into AP containing glycogen granules. It is also proposed that the presence of glycogen in APs under conditions of oxygen and glucose deficit may serve as the source of such energy-containing substrates, such as glucose and ATP, and thus may provide for neuronal survival in pathological states (ischemia/hypoxia).

[Protective role of autotypic contacts under cerebellar neural net injury by toxic doses of NO-generative compounds].

In the present work, cerebellar neural net injury was induced by toxic doses of NO-generative compound (NaNO2). A protective role of glial cells was revealed in such conditions. The present results were compared with those of the previous work concerning the action of high concentration glutamate on the frog cerebellum (Samosudova et al., 1996). In both cases we observed the appearance of spiral-like structures--"wrappers)"--involving several rows of transformed glial processes with smaller width and bridges connecting the inner sides of row (autotypic contact). A statistic analysis was made according to both previous and present data. We calculated the number and width of rows, and intervals between bridges depending on experimental conditions. As the injury increased (stimulation in the NO-presence), the row number in "wrappers" also increased, while the row width and intervals between bridges decreased. The presence of autotypic contacts in glial "wrappers" enables us to suppose the involvement of adhesive proteins--cadherins in its formation. The obtained data suggested that the formation of spiral structures--"wrappers" may be regarded as a compensative-adaptive reaction on the injury of cerebellar neural net glutamate and NO-generative compounds.

[3-D reconstruction of early preimplantation mouse embryo].

Method of 3-D reconstruction approaches for early mouse embryo in preimplantation stages was modified. The developed technique is based on application of light microscopy of serial thin sections and well known soft operating. The designed method enabled us 1) to get serial sections of a single mouse embryo; 2) to create an orthogonal system independent on the sample for orientation of virtual sections. The adequacy of 3-DR protocol was checked on reconstruction of air bubbles embedded in epoxy resin as a model of sphere.

[What is the subject of science "bioinformatics"?].

The paper is concerned with some problems of terminology, in particular the term "bioinformatics". In the last few years, the term "bioinformatics" has been intensively used among molecular biologists to indicate a subject that is only a constituent of genomics and is considered to involve a computer-assisted analysis of all data on nucleotide sequences of DNA. However, a wide circle of scientists, including biologists, physicists, mathematicians, and specialists in the field of cybernetics, informatics, and other disciplines have accepted and accept, as a rule, the "bioinformatics" as a synonym of science cybernetics and as a successor of this science. In this case, the subject of science "bioinformatics" should embrace not only genomics but practically all sections of the biological science. It should involve a study of information processes (storage, transfer, and processing of information, etc.) participating in the regulation and control at all levels of living systems, from macromolecules to the brain of higher animals and human.

[Changes in intercellular exchange intensity in an L cell culture]. / Izmeneniia intensivnosti mezhkletochnogo obmena v kul'ture kletok L.

Intercellular junctions permeable to fluorescein Na were studied with the aid of intracellular glass microelectrodes in the cultures of transformed mouse-embryo cells (L-strain). The degree of coupling was correlated with the cell culture density. In addition, the degree of coupling increased after short-time incubated of the cells with 1mM lanthanum. Such an incubation did not influence other features of cells: the value of the membrane potential, the character of growth or the inclusion of the vital dye neutral red. Some other factors stimulated cellular aggregation (concanavalin A, protamine, decreasing the pH) but did not influence the degree of coupling.

[Effect of Novocaine on the stimulation by lanthanum of intercellular exchange]. / Vliianie novokaina na stimuliatsiiu lantanom mezhkletochnogo obmena.

Some influences on intercellular junctions permeable to Fluorescein Na were studied with the aid of intracellular glass microelectrodes in the cultures of transformed mouse--embryo kidney cells (MTR) and fibroblast--like cells (L). 1 mM of lanthanum increased the degree of coupling by 2 or 3 times. The preceeding incubation of cells with a 0.02% procaine solution protected them from the influence of lanthanum. A possible mechanism of concurrence between lanthanum and procaine on intercellular junctions is discussed.

[Highly permeable contacts and electrical characteristics of the tissue of the normal liver and hepatomas. III. Absence of an effect of the tumor promoter phenobarbital on intercellular contacts in the mouse liver]. / Vysokopronitsaemye kontakty i élektricheskie kharakteristiki tkani normal'noi pecheni gepatom. III. Otsutstvie vliianiia opukholevogo promotora fenobarbitala na mezhkletochnye kontakty v pecheni myshi.

The effect of phenobarbital--a specific promoter of hepatocarcinogenesis--on electrical parameters of mouse liver cells in vitro has been investigated using the conventional microelectrode technique. No alterations were found in cell membrane potentials, input resistances and electrical coupling coefficients measured either immediately after a short-term incubation of isolated livers in the presence of phenobarbital, or after a long-term treatment of the animals per os with the promoter for several weeks.

[3H-colchicine accumulation in a mixed culture of colcemide-resistant and -sensitive cells]. / Nakoplenie 3H-kolkhitsina v smeshannoi kul'ture rezistentnykh i chuvstvitel'nykh k koltsemidu kletok.

Colchicine accumulation was studied in cell monolayer formed by colchicine-sensitive mouse normal fibroblasts and colchicine-resistant cells L-53. Accumulation of 3H-colchicine in the mixed culture of these cells after a 2 hours incubation approached 63% of the total radioactivity in pure cultures of fibroblasts and L-53 cells. Colchicine binding in pure culture of normal fibroblasts somewhat decreased when cell density increased. The results obtained are compatible with the present models of intercellular communication and provide evidence of metabolic cooperation between cells sensitive and resistant to mitostatics.

[Abscence of the tetrodotoxin effect on sodium permeability under conditions of prolonged depolarization]. / Otsutstvie vliianiia tetrodotoksina na natrievuiu pronitsaemost' v usloviiakh dlitel'noi depoliarizatsii

Using frog muscle fibres, it is shown that 10(-6) tetrodotoxin does not practically affect the membrane permeability to lithium ions during a continious depolarization, with the membrane potential being near zero, but causes half a decreased lithium permeability under conditions of normal membrane potential. The absolute value of the lithium permeability for these two states are very close. A 10 mM tetraethylammonium chloride does not influence the lithium permeability of muscle membrane with the normal membrane potential and during a continious depolarization. It is proposed that intact and inactivated sodium channals may have almost equal ion passing capacities, but differ in their gate systems, especially as concerns its interaction with tetrodotoxin.

[Transistorized electrometric intensifier for recording low-amplitude bioelectric activity]. / Tranzistornyi élektrometricheskii usilitel' dlia otvedeniia nizkoamplitudnoi bioélektricheskoi aktivnosti

An amplifer is described which is intended to register a low amplitude bioelectric activity at intra- and extracellular recordings using high ohm electrodes. The increase of real sensitivity (increase of the ratio signal/noise) is reached selectively for each case by a smooth change of the amplifier frequency band, as well as by applying field transistors with little noise at the output stage of the amplifier.

[Highly permeable contacts and the electrical characteristics of normal liver tissue and hepatomas. II. A structural model and calculation of the cell membrane permeability of induced mouse hepatomas]. / Vysokopronitsaemye kontakty i élektricheskie kharakteristiki tkani normal'noi pecheni i gepatom. II. Strukturnaia model' i raschet pronitsaemosti membran kletok indutsirovannykh gepatom myshi.

The values of specific resistances of non-junctional (Rm) and junctional (Rj) membranes of mouse induced hepatoma cells were calculated with the aid of the syncytium theory equations and on the basis of the previously measured input resistances and electrotonic potential spread curves. A three-dimensional model with cable element length equal to two cell diameters, with the length constant value of 600 mkm, and with three contacts per cell was used for calculations. For this model, Rm and Rj were found to be 3300-5600 Ohm . cm2 and 2 . 10(-2) Ohm . cm2, respectively. For the three-dimensional model of normal liver, Rm and Rj amounted to 2400-7200 Ohm . cm2 and 6.5 . 10(-2) Ohm . cm2, respectively.

[Highly permeable contacts and the electrical characteristics of normal liver and hepatoma tissue. I. The highly permeable contacts in induced mouse hepatomas]. / Vysokopronitsaemye kontakty i élektricheskie kharakteristiki tkani normal'noi pecheni i gepatom. I. Vysokopronitsaemye kontakty v indutsirovannykh gepatomakh myshi.

With the aid of intracellular microelectrodes some electrical characteristics of mouse liver were studied in early and late stages of chemical carcinogenesis. In early stages of carcinogenesis as well as in induced hepatomas, the membrane potentials of the cells, the input resistance of cell system and the electrotonic potential distribution in tissue did not differ from the corresponding values in normal liver. It is concluded that at all the stages of carcinogenesis electrical coupling in liver remains unaltered. It is proposed that high-permeable intercellular junctions may play a significant non-specific role in tissue malignization process.

[Ultrastructure of the specialized intercellular contacts in an L-cell culture treated with low concentrations of lanthanum]. / Ul'trastruktura spetsializirovannykh mezhkletochnykh kontaktov v kul'ture L-kletok, obrabotannoi nizkimi kontsentratsiiami lantana.

The electron microscope study of L-cells treated with 1 mM lanthanum has shown an increased amount of gap-like junctions and a decreased number of tight junctions compared to the norm. No damage in the plasma membrane structure and other cell organoids was observed. This may suggest that following the above treatment, the amplified intercellular exchange is associated with the increase in the quantity of intercellular highly permeable junctions. In this case lanthanum may serve as a membrane structure modificator. This effect must be taken into account when the electron microscopists use the lanthanum label for studying specialized intercellular junctions.

[Uniform polarization of fibers and syncytial structures by extracellular electrodes]. / Odnorodnaia poliarizatsiia vololcon i sintsitial'nykh struktur vnekletochnymi élektrodami

The method is described which enables to measure the voltage-current relations of the membrane of fibres and of syncytial structures by means of the current passed through the extracellular electrodes. The method is based on such a distribution of extracellular resistances that the polarization of the membrane was uniform on a large area. For this purpose the extracellular longitudinal gradient of potential had to increase linearly as a function of distance from one of the edges of the preparation. Such a distribution of potentials was achieved by passing current along the conducting agar-layer, the thickness of which decreased with distance from the edge. The length of the agar-layer where the longitudinal potential gradient increased must be large in comparison with the space constant. It is shown that in the zone where polarization is uniform the density of the current crossing the membrane is proportional to the current passed through the preparation independently on the membrane resistance. The method was applied for measuring the voltage-current relations of the horizontal cell membrane in the fish retina.

[The informational role of regular low amplitude movements in the formation of visual signals]. / Informatsionnaia rol' reguliarnykh maloamplitudnykh dvizhenii v formirovanii zritel'nykh signalov.

The role of tremor and drift in the formation of primary receptive fields and signals of space-frequency transformations at the level of retina fovea centralies cells was investigated. The mechanism of organization of direct informational connection between photoreceptors, horizontal and bipolar cells was determined, and the formulas for the synthesis of visual information signals were derived taking into account the frequency of participation of image elements. It is shown that tremor and drift are those mechanophysical processes whose mutual cooperation leads to the formation of the hysteresis signal informationally sufficient for monochrome and polychrome visual recognition.