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This article is focused on the comparison of the accuracy of quantitative, numerical, statistical and nowcasting forecasting methods of convective precipitation including three flood events that occurred in the Zlin region in the years 2015 - 2017. Quantitative prediction is applied to the Algorithm of Storm Prediction for outputs “The probability of convective precipitation and The statistical forecast of convective precipitation”. The quantitative prediction of the probability of convective precipitation is primarily compared with the precipitation forecasts calculated by publicly available NWP models; secondary to statistical and nowcasting predictions. The statistical prediction is computed on the historical selection criteria and is intended as a complementary prediction to the first algorithm output. The nowcasting prediction operates with radar precipitation measurements, specifically with X-band meteorological radar outputs of the Zlín Region. Compared forecasting methods are used for the purposes of verification and configuration prediction parameters for accuracy increase of algorithm outputs.

In the last few years, we could see that a lot of world organizations are contested by different ways, which we are called as cyber threats or cyber risks. Many of organizations are well secured, but the most of them admitted that they are not able to successfully prevent these attacks and they tried to find other ways to mitigate the risk. This paper describes a possible approach to modeling the impact of selected cyber threats in the field of providing cyber-risk insurance. It compares predefined organizational parameters in relation to cyber threats scenarios. The main results include modeling the impact of selected cyber threats on the organization’s parameters. Based on these results, it is possible to quantify possible financial impacts and, on the basis of this, to propose an optimal amount of insurance cover.

In this paper, we focus on one specific firearm, which is air gun, and further on preparation of experimental measurements. In the introduction, it is discussed what other science teams investigate and why. Moreover, it is mentioned a ballistics protection of an individual and, consequently, the justification of why other science teams rather use other firearms than on which we focus. Then, we describe used aids for given experimental measurements. Finally, descriptions and results from our experimental measurements with above mentioned aids are discussed.

The cellular mechanisms of neuroplastic changes in the structure of motoneurons and neuropils of the oculomotor (III) nuclei in mice after a 30-day space flight and 7 days after landing were studied. The results showed that microgravity caused degenerative phenomena in neurons: a decrease in the number of terminal dendritic branches was found both after flight and after readaptation to Earth's gravity. In mice after the flight, the number of axodendritic synapses was less than in the control, and their number was not restored after the readaptation. The number of mitochondria in the motoneurons of animals after the flight also decreased and after the readaptation reached only the control value. In addition, a significant number of dark motorneurons were found in mice after readaptation, which indicates that degeneration was caused not only by microgravity, but also by a reaction to the landing of the biosatellite. On the contrary, in the trochlear nucleus, as we showed earlier (Mikheeva et al. in Brain Res 15(1795):148077. https://doi.org/10.1016/j.brainres.2022.148077 , 2022), after readaptation, the dendrites and synaptic contacts were restored, and mitogenesis is significantly enhanced. It has been suggested that morphological changes in the oculomotor nucleus may be the main cause of microgravity-induced nystagmus., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The gypsy moth ( Lymantria dispar L., Lepidoptera: Erebidae) is a worldwide pest of trees and forests. Lymantria dispar nucleopolyhedrovirus (LdMNPV) belongs to the Baculoviridae family and is an insect virus specific to gypsy moth larvae. In this study, we describe the complete genome sequences of three geographically diverse isolates, H2 (China), J2 (Japan), and T3 (Turkey), of Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV)., Methods: The genomes of isolates H2, J2, and T3 were subjected to shotgun pyrosequencing using Roche 454 FLX and assembled using Roche GS De Novo Assembler. Comparative analysis of all isolates was performed using bioinformatics methods., Results: The genomes of LdMNPV-H2, J2, and T3 were 164,746, 162,249, and 162,614 bp in size, had GC content of 57.25%, 57.30%, and 57.46%, and contained 162, 165, and 164 putative open reading frames (ORFs ≥ 150 nt), respectively. Comparison between the reference genome LdMNPV-5/6 (AF081810) and the genomes of LdMNPV-H2, J2, and T3 revealed differences in gene content. Compared with LdMNPV-5/6, ORF5, 6, 8, 10, 31, and 67 were absent in LdMNPV-H2, ORF5, 13, and 66 were absent in LdMNPV-J2, and ORF10, 13, 31, and 67 were absent in LdMNPV-T3. In addition, the gene encoding the mucin-like protein (ORF4) was split into two parts in isolates H2 and T3 and designated ORF4a and ORF4b. Phylogenetic analysis grouped isolates H2 and J2 in a different cluster than isolate T3, which is more closely related to the Turkish and Polish isolates. In addition, H2 was found to be closely related to a South Korean LdMNPV isolate., Conclusion: This study provided a more detailed overview of the relationships between different geographic LdMNPV isolates. The results showed remarkable differences between groups at the genome level., Competing Interests: The authors declare no conflict of interest, financial or otherwise., (© 2023 Bentham Science Publishers.)

The effect of a single one-hour exposure to three modes of hypobaric hypoxia (HBH) differed in the content of O 2 in inhaled air (FiO 2 -14%, 10%, 8%) in the development of mitochondrial-dependent adaptive processes in the myocardium was studied in vivo. The following parameters have been examined: (a) an urgent reaction of catalytic subunits of mitochondrial enzymes (NDUFV2, SDHA, Cyt b, COX2, ATP5A) in the myocardium as an indicator of the state of the respiratory chain electron transport function; (b) an urgent activation of signaling pathways dependent on GPR91, HIF-1α and VEGF, allowing us to assess their role in the formation of urgent mechanisms of adaptation to hypoxia in the myocardium; (c) changes in the ultrastructure of three subpopulations of myocardial mitochondria under these conditions. The studies were conducted on two rat phenotypes: rats with low resistance (LR) and high resistance (HR) to hypoxia. The adaptive and compensatory role of the mitochondrial complex II (MC II) in maintaining the electron transport and energy function of the myocardium in a wide range of reduced O 2 concentrations in the initial period of hypoxic exposure has been established. The features of urgent reciprocal regulatory interaction of NAD- and FAD-dependent oxidation pathways in myocardial mitochondria under these conditions have been revealed. The data indicating the participation of GPR91, HIF-1a and VEGF in this process have been obtained. The ultrastructure of the mitochondrial subpopulations in the myocardium of LR and HR rats differed in normoxic conditions and reacted differently to hypoxia of varying severity. The parameters studied together are highly informative indicators of the quality of cardiac activity and metabolic biomarkers of urgent adaptation in various hypoxic conditions., Competing Interests: The authors declare no conflict of interest.

The negative effect of hypogravity on the human organism is manifested to a greater extent after the astronauts return to the conditions of habitual gravity. In this work, to elucidate the causes underlying atypical nystagmus, arising after the flight, we studied structural changes in the motoneurons of the trochlear nerve after a 7-day readaptation of mice to the conditions of Earth's gravity. It is known, that motoneurons of the trochlear nerve innervate the muscle that controls the movement of the eyes in the vertical direction. We showed that the number of axodendritic synapses and some other morphological parameters of motoneurons changed by microgravity can return to their original state in 7 days. However, according to some parameters, motoneurons retain a "memory" of the action of microgravity and do not completely restore the structure. The volume of the soma, the shape of the nuclei, the number and orientation of dendrites do not return to pre-flight parameters. The number of dendrites after 7 days of adaptation remained increased, and the proportion of dendrites in the ventrolateral direction became 2.5 times greater than in motoneurons after space flight. The increased number of mitochondria after space flight became even more significant after readaptation. Microgravity-induced plastic changes retain to some extent "memory traces" after readaptation to Earth's gravity. It can be assumed that the restoration of the function of the trochlear nuclei (overcoming nystagmus) is carried out not only by reversible restoration of the structure of neurons, but partially using those mechanisms that are formed in weightlessness., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Dithiocarbamates and derivatives (including disulfiram, DSF) are currently investigated as antineoplastic agents. We have revealed earlier the ability of hydroxocobalamin (vitamin В 12b ) combined with diethyldithiocarbamate (DDC) to catalyze the formation of highly cytotoxic oxidized derivatives of DSF (DSFoxy, sulfones and sulfoxides)., Methods: Electron and fluorescent confocal microscopy, molecular biology and conventional biochemical techniques were used to study the morphological and functional responses of MCF-7 human breast cancer cells to treatment with DDC and B 12b alone or in combination., Results: DDC induces unfolded protein response in MCF-7 cells. The combined use of DDC and B 12b causes MCF-7 cell death. Electron microscopy revealed the separation of ER and nuclear membranes, leading to the formation of both cytoplasmic and perinuclear vacuoles, with many fibers inside. The process of vacuolization coincided with the appearance of ER stress markers, a marked damage to mitochondria, a significant inhibition of 20S proteasome, and actin depolimerization at later stages. Specific inhibitors of apoptosis, necroptosis, autophagy, and ferroptosis did not prevent cell death. A short- time (6-h) exposure to DSFoxy caused a significant increase in the number of entotic cells., Conclusions: These observations indicate that MCF-7 cells treated with a mixture of DDC and B 12b die by the mechanism of paraptosis. A short- time exposure to DSFoxy caused, along with paraptosis, a significant activation of the entosis and its final stage, lysosomal cell death., General Significance: The results obtained open up opportunities for the development of new approaches to induce non-apoptotic death of cancer cells by dithiocarbamates., (Copyright © 2022. Published by Elsevier B.V.)

This study was the first comprehensive investigation of the dependence of mitochondrial enzyme response (catalytic subunits of mitochondrial complexes (MC) I-V, including NDUFV2, SDHA, Cyt b, COX1 and ATP5A) and mitochondrial ultrastructure in the rat cerebral cortex (CC) on the severity and duration of in vivo hypoxic exposures. The role of individual animal's resistance to hypoxia was also studied. The respiratory chain (RC) was shown to respond to changes in environmental [O 2 ] as follows: (a) differential reaction of mitochondrial enzymes, which depends on the severity of the hypoxic exposure and which indicates changes in the content and catalytic properties of mitochondrial enzymes, both during acute and multiple exposures; and (b) ultrastructural changes in mitochondria, which reflect various degrees of mitochondrial energization. Within a specific range of reduced O 2 concentrations, activation of the MC II is a compensatory response supporting the RC electron transport function. In this process, MC I develops new kinetic properties, and its function recovers in hypoxia by reprograming the RC substrate site. Therefore, the mitochondrial RC performs as an in vivo molecular oxygen sensor. Substantial differences between responses of rats with high and low resistance to hypoxia were determined.

During spaceflight and immediately after it, adaptive neuroplastic changes occur in the sensorimotor structures of the central nervous system, which are associated with changes of mainly vestibular and visual signals. It is known that the movement of the eyeball in the vertical direction is carried out by muscles that are innervated by the trochlear nerve (CN IV) and the oculomotor nerve (CN III). To elucidate the cellular processes underlying the atypical vertical nystagmus that occurs under microgravity conditions, it seems necessary to study the state of these nuclei in animals in more detail after prolonged space flights. We carried out a qualitative and quantitative light-optical and ultrastructural analysis of the nuclei of the trochlear nerve in mice after a 30-day flight on the Bion-M1 biosatellite. As a result, it was shown that the dendrites of motoneurons in the nucleus of the trochlear nerve significantly reorganized their geometry and orientation under microgravity conditions. The number of dendritic branches was increased, possibly in order to amplify the reduced signal flow. To ensure such plastic changes, the number and size of mitochondria in the soma of motoneurons and in axons coming from the vestibular structures increased. Thus, the main role in the adaptation of the trochlear nucleus to microgravity conditions, apparently, belongs to the dendrites of motoneurons, which rearrange their structure and function to enhance the flow of sensory information. These results complement our knowledge of the causes of atypical nystagmus in microgravity., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Using the methods of electrophysiology and immunohistochemistry, the effect of the transforming factor beta-1(TGF-β1), an anti-inflammatory cytokine, on the long-term post-tetanic potentiation (LTP) in CA1 field hippocampal slices and the distribution of the GluR1 subunit of the AMPA receptor has been studied. It was shown that TGF-β1 at a concentration of 10 ng/ml did not significantly affect the initial stage of LTP and substantially changed the distribution of synaptic AMPA receptors in response to tetanic stimulation. Twenty five minutes after the tetanization, the main pool of AMPA receptors (90%) was due to the postsynaptic density (PSD). By contrast, LTP in the presence of TGF-β1 was accompanied by less pronounced changes in the distribution of AMPA receptors. Their localization in both pre- and postsynaptic regions remained nearly the same as that in the control. It may be suggested that the normal distribution of AMPA receptors in spinous synapses promotes the stabilization of potentiated synapses, thereby retaining LTP for longer terms., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Drug-induced steatosis (DIS) and drug-induced steatohepatitis (DISH) are two of several types of drug-induced liver injury (DILI). They can be caused by various drugs and may present as acute, potentially lethal disorders or as chronic slowly progressive liver injury. Despite the fact that they are distinct disorders, the slow progressive forms of DIS and DISH are often confused with or misdiagnosed as non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis (NASH), which are much more common and, by definition, not caused by drugs. Currently the only way to identify DIS is via imaging studies or a liver biopsy, while DISH can be identified only through liver biopsy. In addition, diagnosis of either DIS or DISH requires an exhaustive clinical evaluation and comprehensive causality assessment to rule out other possible causes and determine the association with the suspected drug. Furthermore, it is difficult, using existing methods, to monitor the progression of DIS and DISH and to determine the underlying mechanism. Therefore, there is a great unmet need for non-invasive biomarkers that will be able to identify the development of DIS or DISH during drug development and to monitor for progression or regression of the disorder during treatment or following drug discontinuation. Recent developments in the fields of NAFLD and NASH have introduced several novel biomarkers that show promise for the diagnosis, monitoring, and severity assessment of these common diseases. Given the significant overlap in possible underlying mechanisms and histological pattern between NAFLD/NASH and DIS/DISH, these postulated NAFLD and NASH biomarkers may have a potential application to DIS and DISH. This article reviews the existing medical literature and other publically available information pertaining to novel serum biomarkers for NAFLD and NASH, and explores the concurrent identification of these biomarkers for DIS and DISH.

Viviparity evolved in bacteria, plants, ˃141 vertebrate lineages (ichthyosaurs, lizards, fishes, mammals, and others), and in 11 of 44 insect orders. Live-birth cockroaches preserved with brood sac (3D recovered two times optically) included Diploptera vladimir, Diploptera savba, Diploptera gemini spp.n., D. sp.1-2, and Stegoblatta irmgardgroehni from Green River, Colorado; Quilchena, Republic; McAbee, Canada; and Baltic amber, Russia (49, 54, and 45 Ma). They evolved from rare and newly evolved Blaberidae; they radiated circumtropically, later expanded into SE Asia, and have now spread to Hawaii and the SE USA. Association of autapomorphic characters that allow for passive and active protections from parasitic insects (unique wing origami pleating identical with its egg case-attacking wasp) suggest a response to high parasitic loads. Synchronized with global reorganization of the biota, morphotype destabilization in roaches lasted approximately 11-22 Ma, including both the adaptation of novel characters and the reduction of others. Thus, while viviparity can be disadvantageous, in association with new Bauplans and/or behaviors, it can contribute to the evolution of taxa with viviparous representatives that are slightly selectively preferred.

Motor neuron and synapse ultrastructure in the somatic area of oculomotor nerve nuclei (cranial nerve III nuclei) was studied in C57 Black/6 mice. It was shown that that axodendritic and axosomatic synapses were characterized by rounded subjunctional bodies, located at the postsynaptic side of the synaptic contact at some distance from postsynaptic density. At the site of the subjunctional densities, the synaptic gap was expanded to 30 µm. In the same synapse, the synaptic gap could be reduced twice or more. Axosomatic and axodendritic synapses occured on spines. On the soma and dendrites of motoneurons, en passant type of synapses were found. No gap junctions were observed.

Insect cell lines have been initiated since the 1930s and were used to replicate insect baculoviruses as well as arboviruses. Since the latter group of viruses cause serious diseased in man and equines, efforts were expended to characterize the viruses in the new cell lines in attempts to understand the replication cycle at the cellular and molecular levels. Soon it was realized that insect baculoviruses have a potential as viable alternatives to chemicals in the control of agricultural and forest insect pests. The cell lines provided excellent tools to understand the molecular biology of baculoviruses before wide-scale use in the field. During these investigastions, it came to light that baculoviruses can be exploited as vectors for the expression of exogenous proteins and vaccines. The amenability of the virus to genetic modifications and the increasing numbers of permissive cell lines opened new avenues in protein expression. However, not all baculoviruses were able to replicate in cell lines. Indeed, there are no cell lines permissive to viruses belonging to the genera Gammabaculvirus and Deltabaculovirus. Some entomopoxviruses have been replicated in a few cell lines and this paper reports the replication of an entomopoxvirus from the spruce budworm in a homologous cell line., (Copyright © 2013 International Atomic Energy Agency. Published by Elsevier Inc. All rights reserved.)

Using immunogold labeling, excitatory serotoninergic synapses of both chemical and mixed types, were found on the ventral dendrite (VD) of goldfish Mauthner neuron (MN).They are characterized by the presence of several mitochondria in the bouton and by an obligatory desmosome-like contact (DLC) besides the active zone (AZ). Their AZs were commonly found to make contact with the unlabeled chemical crested synapses, which, in turn, directly interacted with VD. These synapses were practically devoid of mitochondria and had no DLCs, thus allowing to identify them as the inhibitory ones. This "two-level" organization of excitatory serotoninergic and inhibitory synapses appears to be related to the reciprocal mechanism of the regulation of MN functional activity by visual input.

Viability, histology and ultrastructure of normal cells and cells of different degrees of malignancy after interaction with dopamine as well as the ability of these cells and isolated G-actin in model experiments to stain by Falck technique were studied. It is shown that dopamine, virtually having no effect on the viability of the "normal" non-tumorigenic transformed cells, noticeably reduces cell viability of slightly tumorigenic cells, causes a significant reduction in viability of attachable cancerous cells and a very significant decrease in cell viability of cancerous cells growing in suspension. The intensity of fluorescence of the cytosole in cells treated with dopamine, has been very high and varied in different cultures, and that of isolated actin directly depended on its concentration. Common to all cell morphological feature of damage from the action of dopamine and the putative substrate of fluorescence was actodopamine filaments network strands (identified on the structure and size), which appears in the cytosole loci, where they were absent in control. The data show that dopamine can be used as an oncotherapeutic remedy and diagnostic tool interacting with G-actin as a cellular target.

The effect of dopamine (DA) on the viability and morphology of cultured tumor THP-1 cells (human acute monocytic leukemia) was studied. DA in concentration of 10(-5) M had virtually no effect on the culture, while in concentration of 10(-4) M to 10(-3) M it stopped the growth and caused a sharp increase in cell death after 24 and 48 hours. Incubation with DA reduced the cell diameter, progressively increased their vacuolization and intensity of fluorescence after treatment by Falck method. Electron microscopical study has shown that cells exposed for 1 day to DA in the concentrations starting with 10(-4) M, demonstrated smoothing of their surface with the disappearance of microvilli and clasmatosis vesicles, actin filaments perforating the plasma membrane, the emergence of an increasingly dense network of filaments in the cytosole and karyoplasm and, finally, apoptotic cell death. It is suggested that the oncotherapeutic cellular target for DA is a cytosolic G-actin, which at a certain DA concentration, turns into filaments that damage the cells, break the cell cycle and cause cell death.

Hymenoptera is a very large and ancient insect order encompassing bees, wasps, ants and sawflies. Fossil records indicate that they existed over 200 million years ago and about 100 million years before the appearance of Lepidoptera. Sawflies have been major pests in many parts of the world and some have caused serious forest defoliation in North America. All baculoviruses isolated from sawflies are of the single nucleocapsids phenotype and appear to replicate in midgut cells only. This group of viruses has been shown to be excellent pest control agents and three have been registered in Canada and Britain for this purpose. Sawfly baculoviruses contain the smallest genome of all baculoviruses sequenced so far. Gene orders among sequenced sawfly baculoviruses are co-linear but this is not shared with the genomes of lepidopteran baculoviruses. One distinguishing feature among all sequenced sawfly viruses is the lack of a gene encoding a membrane fusion protein, which brought into question the role of the budded virus phenotype in Gammabaculovirus biology.

The complete genome of the Orgyia leucostigma nucleopolyhedrovirus (OrleNPV) isolated from the whitemarked tussock moth (Orgyia leucostigma, Lymantridae: Lepidoptera) was sequenced, analyzed, and compared to other baculovirus genomes. The size of the OrleNPV genome was 156,179 base pairs (bp) and had a G+C content of 39%. The genome encoded 135 putative open reading frames (ORFs), which occupied 79% of the entire genome sequence. Three inhibitor of apoptosis (ORFs 16, 43 and 63), and five baculovirus repeated ORFs (bro-a through bro-e) were interspersed in the OrleNPV genome. In addition to six direct repeat (drs), a common feature shared among most baculoviruses, OrleNPV genome contained three homologous regions (hrs) that are located in the latter half of the genome. The presence of an F-protein homologue and the results from phylogenetic analyses placed OrleNPV in the genus Alphabaculovirus, group II. Overall, OrleNPV appears to be most closely related to group II alphabaculoviruses Ectropis obliqua (EcobNPV), Apocheima cinerarium (ApciNPV), Euproctis pseudoconspersa (EupsNPV), and Clanis bilineata (ClbiNPV).

The purpose of the present investigation was to study the morpho-functional organization of a classical object of cytological research - cultured HEp-2 tumor cells, using dopamine as a penetrating agent, inducing the polymerization of cytosolic actin. It was demonstrated that dopamine introduced into the incubation medium reduced viability and caused morphological disturbances of cultured HEp-2 cells; these effects were proportional to dopamine concentrations (1.0 x 10(-4) M to 1.0 x 10(-3) M) and exposure duration (2 to 3 days). These cells, according to ultrastructural data, underwent fusion and lysis because of the appearance of actin filaments network in the loci of globular actin prevalence in control cells. Dopamine receptors had no effect on cytotoxic effect of dopamine. This was indicated by fluorescent microscopical evidence of dopamine penetration into experimental cells in the presence of haloperidol, as well as destruction of HEp-2 cells under the action of pyrimidinethione, similar to dopamine by characteristics, but lacking its own receptors. It is suggested that cytoplasmic target for dopamine is globular actin and that induced polymerization of this cytoskeletal protein caused injury to tumour cells.

The localization in the cell of the protein forming the ATP-dependent potassium-selective channels in the bilayer lipid membrane has been studied. The electron microscope investigation of rat liver and heart tissue sections after their incubation with Abs against this protein and the visualization of the protein with secondary Abs conjugated with colloid gold were carried out. Colloid gold particles were observed both in mitochondrial membranes and in membranes of endoplasmic and sarcoplasmic reticulum. In heart mitochondria, these particles were significantly greater than in liver mitochondria. The localization of the channel protein both in mitochondria and reticulum, as well as the structural similarity between the mitochondrial channel and the precursor of calreticulin suggest that the channel protein belongs to the family of calreticulins. The possible function of the protein as a channel subunit of the mitochondrial ATP-dependent potassium channel is discussed.

BHK-21 cells were incubated in a medium containing dopamine (DA) and then their catecholamine content evaluated by using the Falck cytochemical method. The significant intensification of cell fluorescence as compared to that one in control preparations was detected; this effect was proportional to DA concentration and exposure duration and was more pronounced in cells in suspension than in those attached to the substrate. Simultaneous ultrastructural investigation has shown that an increased intensity of the cytoplasm fluorescence correlated with the appearance of the dense network of fibrils that were morphologically identified as F-actin microfilaments. Prior blockade of dopaminergic receptors by haloperidol did not change the following DA effect both on the fluorescence intensity and cell ultrastructure. The data obtained suggest that DA chronically acting on the living cells was able to penetrate into the cytoplasm, causing actin polymerization and incorporating into the newly formed actin cytoskeleton. Structurally, this may be manifested by cytoskeleton and its derivative hypertrophy, that could have a substantial effect on general morphology of the cell.

The influence of dopamine on the haloperidol of BHK-21 cells being in suspension or attached to substrate was investigated. It was shown that the ultrastructural changes affected mainly the cellular loci enriched by the cytoskeleton actin such as intercellular desmosome-like contacts, microvilli and cortical layer or mesh just beneath the plasmatic membrane. The desmosome-like contacts were hypertrophied, their electron density was increased and fibrilar bridges appeared in specialized contacts. Many microvilli fused with each other and with plasma membrane of the neighboring cells, or, on the contrary, split up. Frequently, the membrane surface between microvilli and particularly their apical parts was seen to be pierced by thin thread, morphologically similar to actin filaments. The cytoplasmatic matrix onto ultrathin sections had blotched appearance and at the ultrastructural level was represented by numerous randomly oriented actin filaments. The effect of dopamine was more pronounced in the BHK-21 cells when being in suspension than in attached to the substrate ones, which presumably occurred due to known lesser differentiation of the cytoskeleton in the formers. Finally, it was established that the preliminary blockade of cellular D2 receptors with haloperidol neither affected the ultrastructure of BHK-21 cells nor prevented the following effect of dopamine. The data obtained suggest the direct interactions of dopamine with the actin cytoskeleton.

The interaction of dopamine (DA) with phospholipid membranes has been investigated. The membrane current in planar bilipid membrane (BLM) modified by amphotericin B in voltage clamp conditions under alternating polarity was shown to symmetrically increase 1.2 times when DA was added outside the BLM. This implies a uniform change of charge on each membrane surface and hence the diffusion of DA within the BLM and its exposure on the internal side. The appearance of single threads and bundles of filaments within the internal liposomal cavities was observed in the ultrastructure of suspended thin-walled liposomes filled with globular actin after the introduction of DA into external solution. This reshaped liposomes into rod-like, spindle-shaped or angular structures. Actin serves as a marker for DA due to its property to polymerize itself under the influence of DA. Thus, the structural reorganization of liposomes manifests the presence of DA inside them and the induction of actin polymerization.

The effects of pyrimidine derivative 3,4-dihydro-2(1H)-pyrimidinethione, (DPT) used as a test-system for detection of tumor growth, on the goldfish Mauthner neurons (MN) ultrastructure and function, as manifested in behavioral changes, were studied. The results of investigations demonstrated that an application of DPT on MN had the effects similar to those of dopamine application, as established earlier, causing the enhancement of MN resistance to fatigue stimulation, accompanied by an increase of the dimensions of the actin containing desmosome-like afferent admembranous synaptic contacts, and formation of the cytoplasmic bundles of actin stress-fibers. Similarity of morpho-functional changes of MN, induced by DPT, an artificial chemical substance, which has no receptors on the neuronal membrane, and by natural neurotransmitter dopamine, allows us to suggest possible trophic stabilizing and polymerizing effects of both substances on cytoskeletal actin due to their direct penetration into postsynaptic neuron.

The aim of this work was to study the effect of dopamine, 20-hydroxyecdysone and chlorpromazine, drugs changing the conductance of gap junctions (GJs), on the ultrastructure of goldfish Mauthner neurons mixed synapses. It was shown that desmosome-like contacts (DLCs) were the presumable targets for dopamine, that increased the electrotonic conductance of mixed synapses. Their hypertrophy, as well as an increase in the number of bridges in their clefts suggests that neuronal actin is involved in the mechanism of dopamine-induced increase of electrotonic conductance. This assumption is further supported by the transformation of extracted monomeric muscular actin into polymeric actin in the presence of dopamine. On the contrary, GJs were shown to be damaged by dopamine treatment. Ecdysone, which is also known to increase the conductance of GJs, changed their structure, increasing their number in the zone of apposition and reducing the profile length, but practically not affecting the DLC structure. It also does not interact with isolated actin in vitro. Therefore, the mechanism of ecdysone action is mainly associated with GJ function. Chlorpromazine, which reduces the conductance of GJs, was shown to damage, partially or completely, DLC admembranous fibrillar material, thus preventing actin polymerization, as shown by in vitro experiments, but had no effect on GJs. Therefore, the mechanism of its action, appears to be based on the changes in the state of neuronal actin.

Using the pyroantimonate method, the distribution of calcium ions in Mauthner cell mixed synapses was studied following their treatment with substances changing gap junction (GJ) synapse electrotonic conductivity. Ecdyson, the drug known to increase GJ conductivity, induced the appearance of calcium pyroantimonate precipitates covering the whole postsynaptic area of GJs, making them highly asymmetric. Formation of precipitate grains was also observed in the cleft of desmosome-like contacts (DLCs). Chlorpromazine, substance that decreases GJ conductivity, induced the formation of precipitates in GJ cleft and on both pre- and postsynaptic sides of their surfaces. No precipitates were seen in DLC cleft. These results show that ecdyson acts as a substance selectively increasing the GJ conductivity with no effect on DLC function. Chlorpromazine has dual effect, by blocking the communication through both GJ and DLC. Thus, using chemicals that change GJ permeability, the possibility of their interaction with actin-containing structures which also participate in the electrotonic signal transfer, should be taken into consideration.

A review. The data concerning the structural changes that accompany long-term potentiation (LTP) of synaptic transmission are analyzed. A bulk of morphological studies is aimed at searching for quantitative and qualitative structural LTP signs and elucidating the involvement of cytoskeleton in their formation. The role of cytoskeletal protein actin in synaptic structural and functional modification is discussed. On the basis of experimental evidence obtained by the authors a proposal is made that actin is involved into the LTP not only as a contractile protein but as a cable which strengthen the electrotonic properties of the synapses.

Using electron microscopic morphometry, the effect of long-term potentiation on the structure of transverse fibrillar bridges localized in a cleft of desmosome-like contacts in mixed synapses of goldfish Mauthner neurons, was studied. The number of bridges was shown to increase with the augmentation of the potentiation level of electrotonic conductivity. In contrast to control (incubation), the structure of bridges was also changed after potentiation. The paired bridges appeared that could have an arrangement within the cleft different from that one in control. On the basis of the present results in conjunction with earlier findings, the possible actin nature of these bridges was suggested. The bridge seems to represent a channel containing actin, arranged in a pattern similar to that one in nanotubules or plasmodesmas, what can, possibly, explain the stability of bridge structure observed after application of [symbol: see text] D and other extrinsic damaging factors.

The effect of highly specific and selective actin-polymerizing and labelling agent, phalloidin, on electrotonic conductivity and structure of the mixed synapses of goldfish Mauthner neurons (MN) was studied. It was shown that the paired subthreshold electrostimulation of afferent input against a background of phalloidin application resulted in the average 80% increase of the amplitude of MN response to the second stimulus. In control group it increased by only 10% and was observed only after suprathreshold stimulation, while subthreshold stimuli were ineffective. We interpret these data as the manifestation of increased conductivity of the mixed synapses, induced by actin polymerization. At the ultrastructural level, phalloidin application at MN and their mixed synapses increased the size and number of actin-containing desmosome-like junctions, as well as the number of fibrillar bridges crossing their cleft. Using the phalloidin-colloid gold marker, the actin nature of these bridges was demonstrated. Interdependent morpho-functional changes found in the mixed synapses, provide the indication of actin involvement in the conduction of electrotonic signal through the mixed synapse. The bridges crossing the cleft of desmosome-like junction could be the structural substrate of this process.

The aim of this investigation was to study the structure of giant myelinated club-shaped terminals (afferent mixed synapses) of goldfish Mauthner (M-) cells in different functional states and to demonstrate calcium ion localization in them using modified pyroantimonate method. It was shown that in intact preparations calcium pyroantimonate precipitate was detected neither in gap junctions (GJ) nor in desmosome-like junctions (DLJ). The fibrillar bridges within DLJ cleft were not contrasted. After natural stimulation, which elaborated a long-term adaptation of M-cells, electron dense precipitate was found in GJ, lining all the cleft. Simultaneously fine granules and aggregates of precipitate appeared in DLJ gap and were intensely deposited over the bridges. It is known that the increase of calcium ion concentration up to and above the level demonstrable by pyroantimonate method blocks the electrotonic coupling and that filamentous actin is able to conduct electrotonic signal as a cationic current. Therefore calcium pyroantimonate staining of DLJ bridges, which were earlier shown to contain actin, indicates the association of calcium ions with filamentous actin, i.e. the functioning of bridges as transsynaptic electrotonic shunts at a moment of fixation. The data obtained allow to make a conclusion that DLJ in mixed synapses have not only a known adhesive function, but also a communicative one. The latter is manifested in extreme conditions, thus permitting synapse to maintain or change their conductivity in accordance with environmental demands.

3-D structures were obtained at rotatory cultivation of CH immortalyzed human fibroblasts attached to glass microcarrier beads. The morphology of cells from these cultures was studied by scanning electron microscopy. A number of structural alterations in fibrillar filopodia of CH cells were revealed as compared with cells grown in stationary monolayer cultures, namely, smaller length, uneven caliber, the presence of curvatures, and disturbed branching pattern. Filopodia displayed unusual formations: protuberance-like and "mammoth's tusk"-like off-shoots, foamy spreadings in distal segments, and spiral windings of filopodia. The susceptibility of CH cells morphology to mechanical environment makes them a promising model for gravitational biology studies.

Comparative ultrastructural investigation of the desmosome-like contacts at chemical and mixed afferent synapses of the goldfish Mauthner neurons was carried out. It was revealed that these contacts at mixed synapses differed from those at chemical ones by thin transverse fibrillar bridges which cross the gap and connect two adjoining membranes of the junction. We suppose that these crossbridges together with gap junctional connexons may serve as a substrate for electronic coupling at mixed synapses demonstrated earlier.

By methods of qualitative and quantitative electronmicroscopy the ultrastructure of mixed synapses of the goldfish Mauthner cell (MC) and their ability to strengthen electrotonic transmission after application of cytochalasin D, a highly specific inhibitor of actin polymerization. On the background of cytochalasin action tetranization of afferent rootlets of acoustic nerve, terminated with mixed synapses on the MC lateral dendrite, failed to induce any long-term potentiation of electronic coupling. On the contrary, a long-term depression of electrotonic transmission was evoked in this case. On the ultrastructureal level such a depression of synaptic conductivity was seen to correlate with a decrease in the number and total length per synaptic apposition of the desmosome-like contacts, known as actin-containing structures, as compared with unstimulated control preparations. In addition, experimental preparations were characterized with unusual quantity of asymmetric desmosome-like contacts, hemidesmosome, whose number during a long-term depression became 4 fold higher than in the control synapses. The data obtained support our recent suggestion on the role of filamentous actin in induction and long-term maintenance of enhanced electrotonic conductivity at mixed synapses.

Ultrastructural synaptic features of long-term potentiation (double increase of amplitude) of electrotonic responses of the goldfish Mauthner neurons (MN) in conditions of prolonged in vitro incubation of medulla oblongata fragments were studied. Potentiation was induced by tetanization of the 8th nerve posterior roots, axonal terminals of which end on distal segments of MN lateral dendrite as piniform mixed synapses and increase their electrotonic conductivity. It was established that potentiated synapses vary from control ones in 1) greater length of synaptic contact; 20 greater (30% higher) ratio of desmosome like structures (DLS); 3) greater area of the DLS individual and total sections (two-fold increase); 4) two-fold decrease of total active zone square. Gap junction (GJ) parameters did not change. Taking an account of the proven actin origin of DLS, reports on actin filaments electron conductivity, close localization of DLS and GJ in the synaptic contact and correlative increase of synapse electric conductivity and DLS parameters. DLS contribution to electrotonic transmission is suggested, direct or mediated by actin interaction with nearby localized GJ connexons.

Hippocampal slices treated with cyclooxygenase inhibitor indomethacin for three min during the sectioning (45 min) or aspirin (0.5 min) in long term (up to 5 days) preservation in periodic nocturnal hypothermia were studied morphofunctionally using light microscopy and electrophysiological registration of induced population responses of area CAI to stimulation of Schaffers collaterals. Structural disorders were revealed in control slices as early as the third hour of incubation and they were destroyed following the first hypothermal challenge (24 hrs following preparation). The structure in slices treated with blockers remained more stable as compared to control ones and the activity was registered until d 3 (aspirin) and 5 (indomethacin). Morphological changes were not immediately, followed by electric activity decline. On the whole it may be suggested that essential viability increase occurred due to destructive processes inhibition mediated by short living cyclooxygenase metabolites.

The state of filament actin in Mauthner neuron (MN) of gold-fish adapted to long-term natural stimulation was investigated after introduction of actin-depolymerizing cytochalasin D. Cytochalasin was demonstrated to cause almost complete disappearance of long actin bundles that were characteristic for the cytoplasm of adapted fish and were absent from MN of intact fish. Polymeric actin supporting the cytoskeleton integrity was suggested to be involved in mechanisms underlying the increase of MN resistance extreme loads.

The ultrastructure of hippocampal neurons in mice subjected to heat treatment for 40 min at 42 degrees C was studied. Such a treatment has been shown to result in significant changes in the structure of pyramidal neurons. An increased chromatin condensation in the nuclei was found in addition to deep invagination of their envelopes and reduction or fragmentation of the reticulum cisterns. These changes were accompanied by mitochondrial swelling and increased number of clathrine vesicles around the Golgi complex. The heat exposure followed by feeding on vitamins and beta-carotin appeared to diminish chromatin condensation and kept the cisterns invariable.

Ultrastructure of Mauthner neurons (MN) was studied in fragments of myelencephalon incubated for 0.5-1.5 hours obtained from immature gold fish. Incubation terms increase along with destruction extent and reorganization of cytoplasmic organelles and nucleus with structure of MN afferent synaptic apparatus less disturbed. Specialized synaptic contacts-active zones, cleft contacts and desmosome-like structure are well retained. The data obtained indicate MN viability during the incubation terms studied, which allows to use surviving grafts with MN as a model for studying ultrastructural bases of certain functional changes of neurons and other neurobiological problems.

A tissue culture was obtained from the sensorimotor cortex of rat embryos after keeping pregnant animals under immobilization-cold stress. The functional state of culture was determined by RNA synthesis intensity. On analysing the tissue morphology, much attention was paid to the pattern of cytoskeleton (microtubules and microfilaments) of neuronal processes. For both periods of cultivation (7 and 14 days), the levels of RNA synthesis in culture of stressed animals were weaker than in the control one by 44 and 34%, resp. After 2 weeks of incubation the density of microtubules, i.e. the number of microtubules per process width, was reduced by 26% in profiles of dendrites. No changes in the number of microfilaments were detected. Besides, destruction of the neuron cytoplasm, redistribution of microtubules within dendrites, and reduction in the number of synaptic endings were noticed. All these alterations seem to be caused by lowering the capability of neurons to form their processes.

Potentiated hippocampal synapses were found to be characterized by specific changes of the cytoskeleton in the postsynaptic spine. Aggregated bundles of actin filaments in the potentiated spines were revealed by decoration with myosin subfragment-1.

The ultrastructural changes in the cytoskeleton of the goldfish Mauthner cells (M-cells) at various functional states induced by intracerebral microinjections of biologically active substances were studied. Under the action of kainic acid, a structural analog of the excitatory neurotransmitter of glutamate, the density of the cytoplasmic matrix increased. Cytotoxin II from the cobra toxin, which blocks acetylcholine transmission, had an opposite effect upon the M-cell cytoskeleton. Simultaneously, in some areas of the neural cytoplasm strands of an electron-dense material of various shapes appeared. They had an unique structure which did not resemble any known cytoskeleton element. The molecular composition of the strands is unknown, but similar strands appeared after injections of phalloidin or cytochalasin B, both disturbing the microfilamental component of the cytoskeleton. Decoration with myosin subfragment-1 revealed actin in intact M-cells which was organized as crossing loose filaments and bundles of parallel fibers. The morphology of the fiber bundles resembles the helical part of the strands appearing after the treatment with phalloidin, cytochalasin B, or cytotoxin II. It is suggested that the cytoplasmic matrix of M-cells is a dynamic system which responds to the functional changes by thickening or loosening of its cytoskeletal elements or by formation of new structures.

Hippocampi of the guinea pig and ground squirrel were used to examine the neuronal structure of CA1 and CA3 field in surviving slices incubated in warm chamber to rehabilitate the functional activity; then the slices were subjected to a prolonged cooling under zero temperatures. It was shown that the structure of the guinea pig hippocampal slices, first of all of the neuronal cytoskeleton, was disturbed at 1.5 h warm incubation. A further 1 h cooling in a refrigerator resulted in a significant swelling of synapses, dendrites and their organelles. In 24 h the structure was severely damaged. It was determined for the first time that the ground squirrel hippocampal slices revealed in the same conditions a high tolerance to both warming and long-term cooling. Even after 5 days in a refrigerator the neurons and dendrites could be clearly seen in slices, nearly intact ultrastructure of their cytoskeleton, synapses and organelles was preserved. A correlation was found between the structural integrity and the functional activity of hippocampal slices. It was suggested that the cytoskeleton may play a crucial role in maintaining the neuronal structure under conditions of both heating and cooling of the hippocampal slices. These data are useful to further elaborating appropriate methods for prolonging the term of incubation and to neurobiological investigation of surviving brain slices.