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The study proposes a model of plant cell as an integral physical and physical-chemical water-dependent system of maximum structural complexity and complete combination of functions. The framework of this model allows analyzing any cell of simpler organization in any degree of reduction, animal cell included. The model justifies priority in the establishment of internal and functional (turgor) cell pressure of its cytoplasmatic solution high-molecular component along the chain: genome-->protein (quality and quantity)-->functional(turgor) pressure-->cell internal pressure-->water content in cell, gradual decrease of which results in cell death.

A mathematical model of the longitudinal dynamics of an isolated strand of the Physarum polycephalum plasmodium has been constructed. Its contractile system is considered as a continual viscoelastic medium with passive and active components. The mathematical description of the longitudinal dynamics of the plasmodial strand is reduced to a system of three first-order differential equations, whose variables are its active stress, deformation, and the intracellular concentration of calcium ions. The model is based on the hypothesis that there exists a feedback loop, which appears because of the influence of strand stretching on the rate of the release of calcium ions, which in turn controls the active contraction and deformation of the strand. Nonlinear interactions between the variables evoke a loss of the stationary state stability and a self-excitation of mechanochemical autooscillations when the external load exceeds some critical value. The results of numerical solutions of the model with the empirically determined viscoelastic parameters are in good agreement with the available experimental data and testify to the adequacy of the description of strand dynamics by the mathematical model in which the contractile apparatus is a part of the cellular control system. In particular, this model well simulates the form and duration of transient mechanochemical processes observed under isotonic and isometric conditions immediately after strand isolation, as well as the subsequent excitation of autooscillations of the contractile activity and their activation by strand stretching.

With the aim of formalization of gastric epithelium kinetics estimation the morphometric analysis of gastric mucosa bioptates was performed in 26 patients without endoscopic signs of stomach pathology. During step estimation of gastric pits at different depth authors analyzed changes of cells size, nucleocytoplasmic ratio, coefficient of nucleus elongation in immature cells of pit bottom (11 zone), differentiating cells in pit intermediate zone (L2), and on mucosa surface (L3 zone). Authors used claster and neuronet analysis (by Statistica and MedStat) to make the mathematical model which permit to determine the proportion of functional zones in normal pit (L--33 +/- 3%; L2--27 +/- 3%; L1--40 +/- 3% of gastric pit depth) and to develop the system of cell standards for each zone. These results can be used to diagnostic of gastric epithelium differentiation changes under pathology and to interpret the barrier properties of gastric epithelium.

The paper is a review of the current state of the important theoretical problem of neurophysiology about the principal possibility of the existence in the nervous system, apart from the major synaptic and contact connections, also of the cytoplasmic syncytial interneuronal connection. Also analyzed are electron microscopy data and results of observation on behavior of living neurons in tissue culture, which allow suggesting the existence in some loci of the nervous system and under certain conditions of the third form of syncytial interneuronal interactions. Regular signs of syncytial perforations are their formation on the ground of membrane contacts and the presence of rounded layers of fused membranes in the zone of defect and of residual membrane structures in the lumen of the perforations. Syncytial connections are formed only in the places, in which glia is absent. In other areas of neuronal bodies or processes, such perforations have never been revealed. The appearance of the cytoplasmic connections in some parts of the nervous system and at certain periods of its development undoubtedly produces an essential effect on functional properties of these parts.

The karyotype formation was studied in the F1BC1 and F1BC2 hybrids of Secale cereale L. ssp. tetraplodium Kobyl. (RRRR, 4x = 28) and Triticale (AABBRR, 6x = 42). The hybrid karyotypes were heterogenomic for homeologous chromosome groups of the wheat and rye genomes. The hybrids differed in cytological stability, the balance of chromosomes of the original species, and the fertility of spikes. The majority of F1BC1 and F1BC2 plants were cytologically unstable and unbalanced in chromosome composition and displayed a low spike fertility. Cytologically stable hexaploids occurred in F1BC1 and F1BC2 at a frequency of 1.0 and 9.5%, respectively. The resulting hexaploid secalotriticum lines (RRAABB, 6x = 42) were genotypically diverse and morphogenetically various. The genetic factors responsible for the diversity of the F1BC1 and F1BC2 rye-triticale amphiploids and early secalotriticum generations are discussed.

Meiosis in anthers and mitosis in somatic cells were studied in reciprocal F1 hybrids of the accession VIR320, which belonged to wild Pisum sativum ssp. elatius (Bieb.) Schmal., and the laboratory line Sprint-1. When VIR320 was used as a maternal form, the hybrids displayed nuclear-cytoplasmic conflict, which caused chlorophyll defects and meiotic abnormalities. One or two chromosomes lagged in the equatorial region during chromosome segregation to the poles, distorting cytokinesis and yielding abnormal microspores. Chlorophyll defects were not observed, and meiotic abnormalities were far less frequent in reciprocal hybrids and in the case of an abnormal paternal inheritance of plastids from Sprint-1. Mitosis lacked overt abnormalities in all of the hybrids.

The absolute criteria developed by the authors have been presented; they allow revealing cytoplasmic syncytial connections between processes of nerve cells in vivo and in vitro at the light microscopy level by using classical methods and time lapse videoshooting in the phase contrast. With aid of electron microscopy, metastable membrane contacts and their perforations, cytoplasmic syncytial interneuronal pores, and fusion of nerve processes are demonstrated. In the culture of isolated molluscan neurons, the process of formation of syncytial connection between processes of the same neuron or of different neurons is reproduced. Processes of one neuron, which have syncytial connection with another neuron, are shown to remain viable after death of its neuronal soma. The cytoplasmic varicosities formed on processes of one neuron are able to overcome the place of syncytial contact with processes of another neuron and to move to the body of the latter. A hypothesis is put forward that the cytoplasmic syncytial connection between nerve processes is formed under the condition of the absence of their glial sheaths.

The article reviews the unique aspects of preparation and performance of cell biology experiments flown on robotic space vehicles Bion and Foton, and gives an overview of key findings in researches made under the author's leadership over the past decades. Described are the criteria of selecting test objects, and the conditions required for preparation and implementation of space and control (synchronous) experiments. The present-day status and issues of researches into cell responsivity to space microgravity and other factors are discussed. Also, potentialities of equipment designed to conduct experiments with cell cultures in vitro and populations of single-celled organisms are presented, as well as some ideas for new devices and systems. Unveiled are some circumstances inherent to the development and performance of space experiments, setting up laboratory facilities at the launch and landing site, and methods of safe transportation and storage of biosamples. In conclusion, the author puts forward his view on biospecies, equipment and areas of research aboard future space vehicles.

We studied the actin cytoskeleton state in Asterias amurensis oocytes within 30 min after the 1-methyladenine-induced maturation until the germinal vesicle breakdown. The total amount of actin remained unchanged during oocyte maturation. In immature oocytes, the major part of actin is not a part of filaments, but in the presence of 1-methyladenine massive actin polymerization began already within 20 min. Electron immunocytochemistry methods demonstrated joint localization of actin and alpha-protein in the cytoplasm. They were redistributed from the cortex to the cytoplasm in the presence of 1-methyladenine. A possible involvement of actin cytoskeleton in transmembrane transduction of the hormonal signal at the postreceptor stages is discussed.

One of the key physiological problems of evolution is elucidation of the role of environmental inorganic factors in origin of life. A statement is substantiated that a highly significant event in evolution of life was the appearance of protocells with the K cytoplasm in K water reservoirs with their subsequent adaptation to the environment in which Na dominated. This step was accompanied by replacement of the cell envelope with the cell plasma membrane. Precursors of animals' elaborated mechanism of maintenance of the K-cytoplasm with Na-counterkation in the environment. In plants, Na remains a trace element, in animals the Na and K contents are approximately equal, but they are present in different fluid phases. In animals presence of Na+ in the external medium, K+ inside cells has become an initial pre-requisition for electrogenesis and appearance of asymmetrical cells. Electrogenesis of these cells has become a physiological pre-requisition for cell differentiation, the appearance of the nerve cell. Asymmetrical cell has provided development of absorption, digestion, excretion, respiration. Formation of the inner medium has become a prerequisite for establishment of homeostasis. Serum osmolality, sodium concentration, pH, Ca2+ are the most rigidly maintained constants in the blood serum of humans.

This review is devoted to annulate lamellae, a specific compartment of endoplasmic reticulum that occurs, presumably, in actively growing and rapidly dividing cells (oocytes, embryonic and tumor cells). We summarized both earlier and recent data on the dustribution of annulate lamellae in various cell types, on their morphology, and the distribution of interaction with intracellular structures at various treatments. As the annulate lamellae contain cytoplasmic pore complexes, a special attention was paid to their relation with nuclear pores. Possible functions of the annulate lamellae in intracellular processes and, particularly, in nuclear envelope assembly, are discussed.

The unified conception of the origin of eukaryotic cells has been proposed. In the author's opinion, evolutionary transformation of prokaryotic cell into eukaryotic cell took place 3.3-1.4 billion years ago and involved the next four stages: 1) the appearance of intracellular membranes due to prokaryotic cell plasmalemma invaginating into its cytoplasm; 2) the cell nucleus formation by the double sheet of intracellular membrane surrounding and sequestrating genetic material of the cell; 3) the appearance of cytoskeleton in parallel with mitotic spindle formation and gradual transition from prokaryotic way of cell division to mitosis; 4) the establishment of symbiosis between the evolving nucleated cell and prokaryotic microorganicsms that subsequently transform into mitochondria and chloroplasts. Apoptosis of cells of the present day multicellular eukaryotic organisms is supposed to be an evolutionary altered response of mitochondrian predecessors to the influence of factors, which are able to damage eukaryotic host cell. The initial biological significance of this reaction pertained to attempts of endosymbionts to leave the host cell as soon as possible, if the probability of its irreversible injury was very high, and by this to escape from their death. It is possible that numerous proteins, known as sensors or transducers of proapoptotic signals in Bcl-2--p53-dependent apoptotic pathway, were initially encoded by mitochondrial genome, whereas antiapoptotic factors and also components of receptor-mediated and granzyme B perforin dependent apoptotic pathways have cellular origin.

During mitosis, rebuilding of the nucleolus is a step-wise process that, above all, includes an assembly of nucleolus-derived foci (NDF) in the cytoplasm of telophase cells. In this study, we performed a comparative analysis of NDF formation in mitotic cells of various mammalian cell cultures, such as green monkey CV1 cells, human HeLa cells, mouse 3T3 cells, and pig PK cells, both in control and following inhibition of rRNA synthesis by actinomycin D or by an adenosine analogue, DRB. The results obtained show that in all examined cell types NDF are formed shortly after or simultaneously with the onset of chromosome segregation to the poles of the mitotic spindle. However, an efficiency of NDF assembly, i.e. the number of NDF per anaphase or telophase cell, and the portion of anaphase and telophase cells containing NDF vary in different cell cultures, being most prominent in CVI and HeLa cells. In these cells, the vast majority of NDF accumulate several proteins of the mature nucleolus, such as B23/nucleophopmin, C23/nucleotin, fibrillarin, and, to a lesser extent, Nop52. The rRNA harbored by NDF is synthesized several hours prior mitosis, and plays an essential role the maintenance of NDF structural integrity. Starting from early stages of the assembly onwards, the NDF are predominantly located in the area occupied by aster microtubules of the mitotic spindle.

The movement of cultured cells along the substratum is a convenient model for studying cell movement in the organism, occurring during embryogenesis, angiogenesis, metastasis, wound closure, etc. The moving cells must control their pseudopodial activity along the perimeter, regulate the attachment and reattachment to the substratum, and pull their body following pseudopodium during their movement along the substratum. As proven by numerous investigations, these processes directly depend on the actomyosin system of cells. The role of microtubules as components of cytoskeleton in cell locomotion still remains obscure. The role of microtubules in cell movement is commonly investigated using microtubule-destructive drugs. Therefore in the final results the accessory drug effect on, for example, signal cascades cannot be excluded. Another mode of action on the microtubule dynamics is centrosome removal from the cells, which is easily realized by their removal together with the nucleus. It has been shown that in cytoplasts of centrosome containing fibroblasts, dynamic instability of microtubules remains. Unlike, in non-centriolar cytoplasts tread milling is observed. Some literature evidence suggests that cytoplasts of cultured cells move along the substratum not worse that intact cells do. In this study cytoplasts with and without centrosome were obtained and identified, and parameters of movement along the substratum (speed, direction) were registered for both these two populations of cytoplasts, and for control intact cells and cells involved in the experiment. The model of experimental wound of monolayer was used, because it guaranteed cell synchronization in respect to movement direction and speed. Centrosome-containing CV-1 cytoplasts displayed radial microtubule array, and centrosome-lacking cytoplasts exhibited chaotic distribution of microtubules, which is characteristic of microtubule tread milling. In addition, both kinds of cytoplasts appeared to move along the substratum much slower than the whole cells. No difference was found is speed and keeping direction between centriolar and non-centriolar cytoplasts.

Using methods of light and electron microscopy and of autoradiography, the morphology of cytoplasm in previtellogenic oocytes of tilapia mossambique was studied. Similar to other bony fishes, mitochondria at the early previtellogenic oocytes are mostly located in the perinuclear cytoplasm to be later distributed over the whole volume of growing oocytes. The Golgi complex is poorly developed. In the peripheral regions of the late previtellogenic oocytes, stickform mitochondria, pinocytotic vesicles and microvilli are observed, along with the perioocyte space formation. In the cytoplasm of previtellogenic oocytes polyribosomes appear. No differences in 3H-leucine incorporation intensity was noticed in oocytes of different previtellogenic stages. The characteristic feature of tilapia mossambique previtellogenic oocytes, in comparison with other bony fishes, is the presence of fat droplets in their cytoplasm.

The organization and functions of genetic systems controlling cytoplasmic male sterility (CMS) in plants are reviewed. Mitochondrial genes that code for specific proteins disturbing the functions of mitochondria have been found by comparisons between CMS lines and fertile F1 hybrids and between forms originating from in vitro cultures (fertile revertants, cybrids). Nuclear fertility-restorer genes abrogate expression of these mitochondrial genes at the transcriptional or posttranslational level and thereby prevent synthesis of their protein products. A high mutability of the mitochondrial genome in cells cultured in vitro results in the elimination or reorganization of CMS-associated mitochondrial genes or in new mutations causing CMS. Several biotechnological methods are considered with respect to their applicability in identifying and transferring CMS-associated genes and in constructing new CMS forms.

Ooplasmic segregation is of great importance in the development of Annelida. The mechanisms of this process are very diverse in different groups of polychaetes, oligochaetes, and leeches (Fernandez et al., 1998). Ooplasmic segregation in Nereis virens is connected with the first meiotic spindle formation and animal-vegetative axis appearance. Spherical polyaxial symmetry of the oocyte transforms into radial stratified symmetry in the course of ooplasmic segregation. There are two main steps of ooplasmic segregation in Nereis virens. The first step begins after the cortical reaction when the central clear cytoplasm reaches the surface of the oocyte. The movement of the cytoplasm is sensitive to nocodazole, colchicine, and cytochalasin B and appears to be mediated by microtubules and, partly, by microfilaments. The second step is not sensitive to the microtubule inhibitors and is mediated mainly by actin filaments. Ooplasmic segregation in Nereis virens may be considered as a primitive form of ooplasmic segregation in Annelida.

We studied the effect of genetic background on mutation frequency of an unstable lz75V allele of the lozenge gene (lz; 1-27.7) isolated from natural populations of Drosophila melanogaster and its mutant derivatives lzB abd lzsl. Genetic composition of the X chromosome containing unstable alleles (X75V chromosome) was shown to affect their mutability. The region of the chromosome proximal to lozenge contains factors required for high mutability of lz75V and lzB. Substitution of a distal part of the X chromosome from a laboratory strain for a homologous part of the X75V chromosome also resulted in stabilizing lz75V, but caused an increase in mutation frequency of lzB. Association between instability of lz75V and the presence of P element with the locus was revealed by in situ hybridization. Studying effects of regulatory elements from a pi 2 P strain showed that the P cytotype is associated with a twofold to threefold decrease in mutation frequency of lzB and lzsl, but P-M hybrid dysgenesis is associated with its slight increase. Regulation of instability of the lozenge gene within the X75V chromosome was assumed to involve three levels: (1) character and topography of a mobile element inserted into the locus, (2) regulatory factors of other X-chromosomal regions, and (3) cytoplasmic factors. The results obtained are discussed in terms of regulation of transposition of mobile genetic elements.

The cortex of Xenopus laevis eggs includes as two components the plasma membrane with underlying microfilaments (external layer) and cytoplasmic matrix with embedded pigment granules (internal layer). The both components of the egg cortex are capable of contraction under the influence of calcium ions. The cortex of the fully grown oocyte is not capable of contraction but acquires it during progesterone-stimulated maturation, when the oocyte is transformed in the egg. It has been proposed on the basis of the data on the cortex cytoskeletal organization that in the oocytes the submembranous microfilaments form an anisotropic network, which is transformed in an isotropic randomly organized network in the egg. The latter is capable of contractile acts. Reorganization of the cytoskeleton in the internal cortex layer leads to formation of the actin contractile gel. The data are provided on the role of actin-associated proteins in changes of organization of the actin cortical cytoskeleton. Mechanisms underlying different sensitivity of microfilaments of the internal and external layers to cytochalasin B are discussed, as well as coordinated (in time) development of the contractility in these layers. A proposed model of development of the cortical contractility during oocyte maturation is based on the concept of two-component cytoskeletal system.

By means of electron microscopic study of ultrastructure of Leydig cells of male adult humpback salmons in the period of spawning migration (stages III-IV of gonad maturity) they were found to be most active before the spawning. Maximum number of mitochondria with tubulovesicular crysts and normal development of Golgi apparatus and smooth endoplasmic reticulum were marked in this period. Decrease of mitochondria number and Golgi apparatus dictyosomes so as liposome-like bodies appearance in the cytoplasm indicated reduction of Leydig cells activity in the period of spawning. After this period fatty drops were presented in the Leydig cells cytoplasm, mitochondrial matrix acquired greater electron density and dark granules appeared in it. Signs of physiological regeneration outset were seen in dying male salmons. This is regarded as an evidence of secondary monocyclicity of the Pacific Ocean salmons.

The review considers the data on the morphine and enkephalins electrophysiological effects which were obtained in snail neurons and might be explained by a decrease in the level of cAMP in the cytoplasm. These effects are: a membrane hyperpolarization, a depression of the bursting activity, an inhibition of the excitatory serotonin and dopamine responses.

The role of thyroxin and thyroxin action modulator (cytoplasmic protein mediating some hormonal effects on the mitochondria and nucleus) in rat liver and brain protein phosphorylation was studied in experiments. In the liver, an organ sensitive to thyroid hormones, the modulator was found to stimulate the activity of specific protein kinases contributing to protein phosphorylation, and co-incubation of physiologic concentrations of T4 with the modulator enhanced the stimulatory effect. In the brain change of the thyroid status did not change the protein kinase activation. Incubation of T4 and thyroxin effect modulator did not change the enzymic activity either.

The intracellular and intralysosomal pH were studied on living monolayer cell cultures SPEV (pig embryo kidney), CHC (Chinese hamster's fibroblasts), NGUK-1 (neurinoma of Gasser's gland of rat), and also on primary cell cultures of rat's hepatocytes and chick embryo fibroblasts. In cytoplasm and lysosomes of these cells were found out pH changes during cells cycle and cell cultivation. There was also showed a heterogeneity of different parts of cells and lysosomes, and circahoral pH oscillations were registered. So there was found a spatial and temporal pH mosaity of living cells. The probable role of intracellular pH changes via regulator of cell vital activity is discussed.

A water-soluble thermostable factor from rat liver cytoplasm whose activity decreases during starvation, causes the uncoupling of oxidative phosphorylation and stimulates pyruvate oxidation in rat liver mitochondria. The activity of this factor is insensitive to pronase treatment. Gel filtration and ion-exchange chromatography resulted in three low molecular weight water-soluble fractions which bear a negative charge at alkaline values of pH and induce electrophoretic transport of K+ and phosphate across the inner mitochondrial membrane. The effect of this factor on K+ transport is manifested at pH less than or equal to 7.0, that on phosphate transport-at pH 6.5-7.6.

Survival and morphogenesis of the enucleated fragments of Acetabularia has been studied after their reconstruction from the cell membrane and the endoplasm. Membranes and endoplasms of different species as well as of the same species but from plants in different functional states and with different regenerative abilities were combined. It was shown that inability of plants for growth and morphogenesis was due to the membrane state. When reconstructing anuclear fragments from membranes and endoplasms of different species or the same species but from plants in different functional states, a phenomenon of membrane-endoplasm incompatibility was found.

The neurotransmitters found in early ("pre-nervous") embryos of Metazoa operate at the intracellular level. In these embryos, the transmitter receptors (or their functional equivalents) and adenylate cyclase coupled with them are localized intracellularly. Intracellular functions of neurotransmitters may be also found in the differentiated neurons of adult animals.

The effect of proliferation stimulating factors (PSF) obtained from regenerating liver on the cholesterol esterification in blood serum under deep tetrachloromethane intoxication has been studied in experiments with white rats. Three phases in dynamics of cholesterol content in blood serum have been picked out after a single tetrachloromethane injection. The content of total cholesterol and cholesterol esters reduces during the first phase (24 h), during the second phase (3-7th day) it increases and during the third phase (15th day) these values become normal. PSF injection does not produce any influence on the nature of blood cholesterol under deep tetrachloromethane intoxication, but stimulates the processes of cholesterol ester formation in blood serum.

Interferometric microscopic study of living neurons of the isolated brain of Limnaea stagnalis has revealed some fluctuation of dry weight of the cytoplasm and the nucleolus in the absence of electrical activity of the neuron. The character of these changes was different for different neurons. During the neuron-induced generation of action potentials in response to the intracellular electrical stimulation, the changes in dry weight became similar for all neurons: the dry weight of the cytoplasm increased and the dry weight of the nucleolus decreased. This effect grew with the time of stimulation.

Synthesys of collagen and non-collagen proteins was investigated in a cell-free system in the presence of free and bound polysomes isolated from chick embryos. Of total radioactive proteins synthesized on bound and free polysomes the amount of peptides digested by bacterial collagenase comprised 25-40% and 5-7% respectively. These data showed that collagen was predominantly synthesized by bound polysomes. Free polysomes were found to be much more active than bound ones in non-collagen protein synthesis. When bound polysomes detached from membranes by detergent treatment were incubated in a cell-free system, a release of non-collagen proteins into the incubation medium increased sharply, but the release of collagen peptides was as negligible as in the case of untreated polysomes. Kinetic studies of collagen synthetizing activity of polysomes bound to or detached from membranes suggested the role of endoplasmic membranes in stabilizing collagenous polysomes.

Cytoplasmatic glycopeptide-induced bicarbonate ion electrogenic transport through mitochondrial membrane has been studied. Glycopeptide, described earlier as a factor increasing inner mitochondrial membrane permeability for phosphate ions, has been also shown to induce bicarbonate ion electrogenic transport through inner mitochondrial membrane. HCO3- ion transport, induced by cytoplasm glycopeptide is realized by pH-dependent pore. The interrelation of cytoplasm glycopeptide with mitochondria is regulated by mitochondrial energization.

The ultrastructure of nucleus and cytoplasm in regenerating cells of Acetabularia mediterranea differs from that in normally growing ones: the nucleus of regenerating cells form numerous outgrowths; the cortical layer of nucleolus disintegrates markedly; the emission of nucleolar material in the nucleoplasm is observed. In the cytoplasm the portion of active chloroplasts increases and a great number of tubular fibrils appears. In the cytoplasm of regenerating cells the Golgi dictyosomes occur more frequently and the vesicles at their ends are larger than in that of normally growing cells. The changes of macromolecular organization of the nucleus and cytoplasm in question observed at the earlier stages of regeneration (2--12 hrs) suggest the increase of metabolic activity of cells.

The main principles on the theory of germ plasma by A. Weismann are briefly presented; a number of his genetic-embryological hypotheses proved to be prophetic. Modern notions on the germ plasma are critically discussed, as well as the resulting from them the conception on continuity of totipotent cells (the source of germ cells) in the line of generations, that is historically connected with M. Nussbaum--A. Weismann's notions on continuity of the embryonic pathway. The term totipotency is sometimes used inaccurately; it means ability to formation of a whole organism. In Metazoa zygota and isolated blastomeres, at a regulative type of development, and groups of somatic cells or fragments of the organism, at an asexual reproduction and somatic embryogenesis, possess this ability. In ontogenesis totipotency is lost both by the somatic and by the germ cells because of their specialization and is recreated with the beginning of every ontogenesis when zygota is formed. The germ cells are always a product of the organism--unicellular or multicellular, and their specialization in all its manifestations is the result of integrative influences of the organism as a whole of them. Certain reasons are presented for supporting ideas on germ cells as one of the lines of cell differentiation. The main, if not the only contradiction in the problem concerning relation of the germ and somatic cells is, at the present time, the thesis on continuity of totipotent cells in the line of generations.

Fertilization of eggs and effects of many growth factors on the membrane receptors of the cultured somatic cells induce similar changes in the plasma membrane transport properties, which determine changes in Ca2+ and H+ concentrations in the cytoplasm. The data are discussed which favour the concept that Ca2+ and H+ are secondary messengers of growth-stimulating influences and control many intracellular processes related to cell multiplication.

Successive stages of the process characterizing the release of the nucleoli and part of the nuclei contents into the reticular cell cytoplasm were recorded in the primary cultures of the lymph nodes of albino mice with transplantable leukemia. Comparison of the results obtained with the autoradiographic data pointing to the high proliferative and metabolic activity of the reticular cells permits a suggestion that the recorded phenomenon reflected the secretory function of the stroma cells of the hemopoietic organs at the morphological level.

The cytoplasm of the egg vegetal hemisphere plays the determining role in the isolation and differentiation of germ cells. Cytoplasmic factors of unknown nature prevent certanin blastomeres from somatic differentiation. In the developing germ cells, a large amount of material (in which acid proteins are a constant component) passes from the nucleus to the cytoplasm. This fine fibrous material may take the form of nucleolus-like bodies or dense granules (polar granules in the insect eggs, dense bodies in the amphibian germ plasm, intermitochondrial cement in oocytes of various animals, chromatoid body in spermatocytes). The application of the term "determinants of germ cells" for designation of these structure, as it takes in the electron microscopy literature, appears to be incorrect. Their appearance is a consequence of the determining influence of cytoplasmic factors, rather than their cause. In lower invertebrates, the germ cells may arise in adult specimens due to the embryonic reserve of totipotent elements (neoblasts or interstitial cells). The transformation of these cells in the germ ones is accompanied by the release of a great amount of fine fibrous material from the nucleus to the cytoplasm as well. The problem of determinants of germ cells is considered with respect to the problem of ooplasmic segregation.

The yolk segregation in the developing Rana temporaria egg was studied both in vivo and under the effect of clinostate rotation, i. e. slow rotation around the horizontal axis imitating the state of weightlessness. From the moment of fertilization and during the whole period of cleavage the yolk was shown to subdivide succesively in distinct phases which differ by the characteristic value of yolk granules. During the normal development, in spite of the marked variability of form and mutual position of phases, the main elements of their animal-vegetative order are preserved. Under the effect of clinostate rotation the process of normal segregation becomes destabilized and variations in the egg structure are expressed by the beginning of gastrulation in the diversity of variants of distribution of the cellular material competent to different morphogenetic movements.

The insulin-dependent cytoplasmic factor-regulator (IDR) was shown to inhibit pyruvate and succinate oxidation by the rat liver mitochondria. In view of the fact that insulin increases and adrenaline decreases IDR activity in the liver cytoplasm it is suggested that oxidation of the substrate in mitochondria in vivo is regulated by changes in IDR content in cytoplasm. It was shown that adrenaline-activated oxidation apart from decreased activity of IDR in cytoplasm is induced by a different mechanism not related to IDR content.

The cytoplasm of mature non-activated and cleaving eggs of A. stellatus and R. temporaria had no cytostatic effect. The cytoplasm treated with EGTA, being injected in one of two blastomeres of the cleaving egg of the same species, inhibits fully or partially the cleavage. The nuclei in the "arrested" blastomeres had, however, vesicular structure but were not blocked at metaphase, as could be expected if the cleavage was inhibited by a cytostatic factor described by Masui (1974). The portion of perished embryos and "arrested" blastomeres was shown to increase with the dose of EGTA injected in the egg, donor of cytoplasm. In the experiments with reciprocal injections of the intact cytoplasm of the mature non-activated eggs in one of two blastomeres of the recipient embryo carried out on R. temporaria and X. laevis, the cytoplasm of X. laevis only arested the cleavage but in this case as well only 4 out of 32 "arrested" blastomeres were at metaphase. The cytostatic effect observed in our experiments was not, hence, similar to that observed by Masui on R. pipiens.

The karyoplasm (the contents of germinal vesicle) of the Bufo viridis, Xenopus laevis, and Acipenser stellatus oocytes maturing under the influence of progesterone acquires the ability to induce the maturation (germinal vesicle breakdown) of the full grown oocytes, when injected into them. This ability arises in the karyoplasm earlier than in the cytoplasm and is preserved until the germinal vesicle breakdown.

In acute rat kidney insufficiency, caused by bilateral nephrectomy or ureter ligation, functional activity of hepatocyte cytoplasmic structure was decreased. Estimation of the cytoplasmic structures functional state included studies of hexenal anesthesia duration, determination of cytochromes P-450 and b5 content in liver microsomal fraction as well as of activities of amidopyrine-N-demethylase and aniline hydroxylase. The alterations of these parameters occurred apparently due to the effect of high concentrations of urea on liver tissue.

A thermostable low molecular weight glycopeptide containing syalic acids, which uncouples mitochondrial oxidative phosphorylation, has been detected, isolated and purified from rat liver cytoplasm. In the presence of the glycopeptide, oxidative phosphorylation in rat liver mitochondria is uncoupled by low physiological concentrations of Ca2+, which otherwise do not have any appreciable effect on the mitochondria. Oxidative phosphorylation uncoupling by the glycopeptide is accompanied by an increase of the mitochondrial volume. This process has a limited amplitude and is regulated by changes in Ca2+ concentration in the extramitochondrial space. The glycopeptide has been shown to induce K+ transport across the inner mitochondrial membrane, this effect is enhanced by Ca2+.