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The Faculty of Computer Systems and Technology at Technical University – Sofia undertook analyses and experiments on the use of Artificial Intelligence methods in the field of Information Security. In the course of the study a Cyber Defence related to the classification consisting of three phases has been proposed: Operative Cyber Intelligence, Tactical Cyber Intelligence and Incident Handling. It has been found that there is no universal Artificial Intelligence method effective for all phases mentioned above and for all applications. In each case, a set of criteria should be developed to select (and then experiment) an appropriate method (or combination of methods). A selection of methods for the first two stages of Cyber Defence was described in previous work. In the present paper are considered some of the considerations related to effective use of appropriate methods for the Incident Handling phase.

Abstract Background A number of epidemiological studies have established a link between insulin resistance and the prevalence of depression. The occurrence of depression was found to precede the onset of diabetes and was hypothesized to be associated with inherited inter-related insufficiency of the peripheral and central insulin receptors. Recently, dicholine succinate, a sensitizer of the neuronal insulin receptor, was shown to stimulate insulin-dependent H2O2 production of the mitochondrial respiratory chain leading to an enhancement of insulin receptor autophosphorylation in neurons. As such, this mechanism can be a novel target for the elevation of insulin signaling. Results Administration of DS (25 mg/kg/day, intraperitoneal) in CD1 mice for 7 days prior to the onset of stress procedure, diminished manifestations of anhedonia defined in a sucrose test and behavioral despair in the forced swim test. Treatment with dicholine succinate reduced the anxiety scores of stressed mice in the dark/light box paradigm, precluded stress-induced decreases of long-term contextual memory in the step-down avoidance test and hippocampal gene expression of IGF2. Conclusions Our data suggest that dicholine succinate has an antidepressant-like effect, which might be mediated via the up-regulation of hippocampal expression of IGF2, and implicate the neuronal insulin receptor in the pathogenesis of stress-induced depressive syndrome.

The Drosophila abnormal spindle ( asp ) gene was discovered about 40 years ago and shown to be required for both mitotic and meiotic cell division. Subsequent studies showed that asp is highly conserved and that mutations in its human ortholog ASPM ( Abnormal Spindle-like Microcephaly-associated ; or MCPH5 ) are the most common cause of autosomal recessive primary microcephaly. This finding greatly stimulated research on ASPM and its fly and mouse ( Aspm ) orthologs. The three Asp orthologous proteins bind the microtubules (MTs) minus ends during cell division and also function in interphase nuclei. Investigations on different cell types showed that Asp/Aspm/ASPM depletion disrupts one or more of the following mitotic processes: aster formation, spindle pole focusing, centrosome-spindle coupling, spindle orientation, metaphase-to-anaphase progression, chromosome segregation, and cytokinesis. In addition, ASPM physically interacts with components of the DNA repair and replication machineries and is required for the maintenance of chromosomal DNA stability. We propose the working hypothesis that the asp / Aspm / ASPM genes play the same conserved functions in Drosophila , mouse, and human cells. Human microcephaly is a genetically heterogeneous disorder caused by mutations in 30 different genes that play a variety of functions required for cell division and chromosomal DNA integrity. Our hypothesis postulates that ASPM recapitulates the functions of most human microcephaly genes and provides a justification for why ASPM is the most frequently mutated gene in autosomal recessive primary microcephaly., Competing Interests: The authors declare no conflict of interest.

Centrosome-containing cells assemble their spindles exploiting three main classes of microtubules (MTs): MTs nucleated by the centrosomes, MTs generated near the chromosomes/kinetochores, and MTs nucleated within the spindle by the augmin-dependent pathway. Mammalian and Drosophila cells lacking the centrosomes generate MTs at kinetochores and eventually form functional bipolar spindles. However, the mechanisms underlying kinetochore-driven MT formation are poorly understood. One of the ways to elucidate these mechanisms is the analysis of spindle reassembly following MT depolymerization. Here, we used an RNA interference (RNAi)-based reverse genetics approach to dissect the process of kinetochore-driven MT regrowth (KDMTR) after colcemid-induced MT depolymerization. This MT depolymerization procedure allows a clear assessment of KDMTR, as colcemid disrupts centrosome-driven MT regrowth but not KDMTR. We examined KDMTR in normal Drosophila S2 cells and in S2 cells subjected to RNAi against conserved genes involved in mitotic spindle assembly: mast / orbit / chb ( CLASP1 ), mei-38 ( TPX2 ), mars ( HURP ), dgt6 ( HAUS6 ), Eb1 ( MAPRE1/EB1 ), Patronin ( CAMSAP2 ), asp ( ASPM ), and Klp10A ( KIF2A ). RNAi-mediated depletion of Mast/Orbit, Mei-38, Mars, Dgt6, and Eb1 caused a significant delay in KDMTR, while loss of Patronin had a milder negative effect on this process. In contrast, Asp or Klp10A deficiency increased the rate of KDMTR. These results coupled with the analysis of GFP-tagged proteins (Mast/Orbit, Mei-38, Mars, Eb1, Patronin, and Asp) localization during KDMTR suggested a model for kinetochore-dependent spindle reassembly. We propose that kinetochores capture the plus ends of MTs nucleated in their vicinity and that these MTs elongate at kinetochores through the action of Mast/Orbit. The Asp protein binds the MT minus ends since the beginning of KDMTR, preventing excessive and disorganized MT regrowth. Mei-38, Mars, Dgt6, Eb1, and Patronin positively regulate polymerization, bundling, and stabilization of regrowing MTs until a bipolar spindle is reformed.

Moonlighting proteins can perform one or more additional functions besides their primary role. It has been posited that a protein can acquire a moonlighting function through a gradual evolutionary process, which is favored when the primary and secondary functions are exerted in different cellular compartments. Transcription factors (TFs) and splicing factors (SFs) control processes that occur in interphase nuclei and are strongly reduced during cell division, and are therefore in a favorable situation to evolve moonlighting mitotic functions. However, recently published moonlighting protein databases, which comprise almost 400 proteins, do not include TFs and SFs with secondary mitotic functions. We searched the literature and found several TFs and SFs with bona fide moonlighting mitotic functions, namely they localize to specific mitotic structure(s), interact with proteins enriched in the same structure(s), and are required for proper morphology and functioning of the structure(s). In addition, we describe TFs and SFs that localize to mitotic structures but cannot be classified as moonlighting proteins due to insufficient data on their biochemical interactions and mitotic roles. Nevertheless, we hypothesize that most TFs and SFs with specific mitotic localizations have either minor or redundant moonlighting functions, or are evolving towards the acquisition of these functions.

Mammalian oviducts contain smooth muscles and inward-facing ciliated epithelium. Muscular contractions, not ciliary beating, propel oocytes through the oviduct towards the uterus. In crawling gastropods (unique models for studying the functioning of phasic smooth muscles), muscular contractions, propagating along the foot sole, play a principal role in determining the crawling rate. We have described the muscular mechanisms controlling the crawling rate and hypothesize here that the same mechanisms provide embryo transportation through the human fallopian tube. The data collected for gastropods were transferred to the human fallopian tube, using embryo speed and tube length (tonus) instead of crawling speed and sole length. Smooth muscle active states: tonic contraction/relaxation and rhythmic contractions (peristalsis) are involved in ovum transport. The ovum/embryo speed is linearly correlated with the tonus of the longitudinal and/or the circular muscles of the tube. Some known bioactive substances control muscular tonus and we suppose embryo speed through the contraction force of muscle cells involved in peristaltic waves. Other known substances facilitate peristalsis and we suppose that they have no effect on muscular tonus and increase dose-dependently embryo speed through the number of muscle cells recruited in peristaltic waves (at a constant wave frequency). This number depends on the physiological state of the woman. The combination of all possible effects and the ability of muscles to contract rhythmically determine the embryo speed and its implantation site. This hypothesis is the first description of the tubal muscular mechanisms that determine normal and any type of ectopic pregnancy at chronic disorders of tubal contractility. How to predict ectopic pregnancy? We have reason to assume that the intensity of rhythmic uterine contractions reflects that in the fallopian tube. It is known that uterine contractility significantly increases during the preovulatory phase and decreases during the mid-luteal phase. The hypothesis supposes that in women with increased risk of ectopic pregnancy, decreased uterine contractility during the preovulatory phase in comparison with the norm indicates a future tubal/abdominal gestation; increased uterine contractility during this phase and/or the mid-luteal phase as compared to the norm points to a future cervical pregnancy. The optimal methods for recording uterine activity are up to clinicians., (Copyright © 2019. Published by Elsevier Ltd.)

The Drosophila Nonspecific Lethal (NSL) complex is a major transcriptional regulator of housekeeping genes. It contains at least seven subunits that are conserved in the human KANSL complex: Nsl1/Wah (KANSL1), Dgt1/Nsl2 (KANSL2), Rcd1/Nsl3 (KANSL3), Rcd5 (MCRS1), MBD-R2 (PHF20), Wds (WDR5) and Mof (MOF/KAT8). Previous studies have shown that Dgt1, Rcd1 and Rcd5 are implicated in centrosome maintenance. Here, we analyzed the mitotic phenotypes caused by RNAi-mediated depletion of Rcd1, Rcd5, MBD-R2 or Wds in greater detail. Depletion of any of these proteins in Drosophila S2 cells led to defects in chromosome segregation. Consistent with these findings, Rcd1, Rcd5 and MBD-R2 RNAi cells showed reduced levels of both Cid/CENP-A and the kinetochore component Ndc80. In addition, RNAi against any of the four genes negatively affected centriole duplication. In Wds-depleted cells, the mitotic phenotypes were similar but milder than those observed in Rcd1-, Rcd5- or MBD-R2-deficient cells. RT-qPCR experiments and interrogation of published datasets revealed that transcription of many genes encoding centromere/kinetochore proteins (e.g., cid, Mis12 and Nnf1b), or involved in centriole duplication (e.g., Sas-6, Sas-4 and asl) is substantially reduced in Rcd1, Rcd5 and MBD-R2 RNAi cells, and to a lesser extent in wds RNAi cells. During mitosis, both Rcd1-GFP and Rcd5-GFP accumulate at the centrosomes and the telophase midbody, MBD-R2-GFP is enriched only at the chromosomes, while Wds-GFP accumulates at the centrosomes, the kinetochores, the midbody, and on a specific chromosome region. Collectively, our results suggest that the mitotic phenotypes caused by Rcd1, Rcd5, MBD-R2 or Wds depletion are primarily due to reduced transcription of genes involved in kinetochore assembly and centriole duplication. The differences in the subcellular localizations of the NSL components may reflect direct mitotic functions that are difficult to detect at the phenotypic level, because they are masked by the transcription-dependent deficiency of kinetochore and centriolar proteins., Competing Interests: The authors have declared that no competing interests exist.

Background: The calmodulin-regulated spectrin-associated proteins (CAMSAPs) belong to a conserved protein family, which includes members that bind the polymerizing mcrotubule (MT) minus ends and remain associated with the MT lattice formed by minus end polymerization. Only one of the three mammalian CAMSAPs, CAMSAP1, localizes to the mitotic spindle but its function is unclear. In Drosophila, there is only one CAMSAP, named Patronin. Previous work has shown that Patronin stabilizes the minus ends of non-mitotic MTs and is required for proper spindle elongation. However, the precise role of Patronin in mitotic spindle assembly is poorly understood., Results: Here we have explored the role of Patronin in Drosophila mitosis using S2 tissue culture cells as a model system. We show that Patronin associates with different types of MT bundles within the Drosophila mitotic spindle, and that it is required for their stability. Imaging of living cells expressing Patronin-GFP showed that Patronin displays a dynamic behavior. In prometaphase cells, Patronin accumulates on short segments of MT bundles located near the chromosomes. These Patronin "seeds" extend towards the cell poles and stop growing just before reaching the poles. Our data also suggest that Patronin localization is largely independent of proteins acting at the MT minus ends such as Asp and Klp10A., Conclusion: Our results suggest a working hypothesis about the mitotic role of Patronin. We propose that Patronin binds the minus ends within MT bundles, including those generated from the walls of preexisting MTs via the augmin-mediated pathway. This would help maintaining MT association within the mitotic bundles, thereby stabilizing the spindle structure. Our data also raise the intriguing possibility that the minus ends of bundled MTs can undergo a limited polymerization.

Background: Expression of the CNDP2 gene is frequently up- or down-regulated in different types of human cancers. However, how the product of this gene is involved in cell growth and proliferation is poorly understood. Moreover, our knowledge of the functions of the CNDP2 orthologs in well-established model organisms is scarce. In particular, the function of the D. melanogaster ortholog of CNDP2, encoded by the CG17337 gene (hereafter referred to as dCNDP2), is still unknown., Results: This study was aimed at developing a set of genetic and molecular tools to study the roles of dCNDP2. We generated a dCNDP2 null mutation (hereafter ∆dCNDP2) using CRISPR/Cas9-mediated homologous recombination (HR) and found that the ∆dCNDP2 mutants are homozygous viable, morphologically normal and fertile. We also generated transgenic fly lines expressing eGFP-tagged and non-tagged dCNDP2 protein, all under the control of the UAS promoter, as well as polyclonal antibodies specific to dCNDP2. Using these tools, we demonstrate that only one of the two predicted dCNDP2 isoforms is expressed throughout the different tissues tested. dCNDP2 was detected in both the cytoplasm and the nucleus, and was found to be associated with multiple sites in the salivary gland polytene chromosomes., Conclusions: The dCNDP2 gene is not essential for fly viability under standard laboratory conditions. The subcellular localization pattern of dCNDP2 suggests that this protein might have roles in both the cytoplasm and the nucleus. The genetic and molecular tools developed in this study will allow further functional characterization of the conserved CNDP2 protein using D. melanogaster as a model system.

Crawling gastropods are unique models for studying the functioning of smooth muscles and ciliated epithelia, since they cover the foot sole and are involved in locomotion, allowing for direct investigation. Two types of crawling are known: creeping by muscular waves in terrestrial gastropods such as Helix and сiliary gliding in aquatic gastropods such as Lymnaea. It was found that the smooth muscles that underlie the ciliated epithelium in Lymnaea are involved in gliding and contribute significantly to fast crawling. Thus, the locomotor apparatus is fundamentally the same in both snails and the difference between crawling reflects an adaptation to a habitat. The control of crawling speed is also the same. Tonic contraction, relaxation, and rhythmic contractions are involved in this control. During a locomotor episode, the sole length and crawling speed spontaneously change and directly correlate with each other via the contraction force of the muscle cells in the locomotory waves. Dopamine, unlike ergometrine, decreases the sole length and crawling speed. Serotonin stimulates, increases crawling and determines the number of muscle cells involved in the locomotory waves for each locomotor episode. This control (taking into account heterogeneity) apparently might exist in any other phasic smooth muscle, including vertebrates.

Background: S2 cells are one of the most widely used Drosophila melanogaster cell lines. A series of studies has shown that they are particularly suitable for RNAi-based screens aimed at the dissection of cellular pathways, including those controlling cell shape and motility, cell metabolism, and host-pathogen interactions. In addition, RNAi in S2 cells has been successfully used to identify many new mitotic genes that are conserved in the higher eukaryotes, and for the analysis of several aspects of the mitotic process. However, no detailed and complete description of S2 cell mitosis at the ultrastructural level has been done. Here, we provide a detailed characterization of all phases of S2 cell mitosis visualized by transmission electron microscopy (TEM)., Results: We analyzed by TEM a random sample of 144 cells undergoing mitosis, focusing on intracellular membrane and microtubule (MT) behaviors. This unbiased approach provided a comprehensive ultrastructural view of the dividing cells, and allowed us to discover that S2 cells exhibit a previously uncharacterized behavior of intracellular membranes, involving the formation of a quadruple nuclear membrane in early prometaphase and its disassembly during late prometaphase. After nuclear envelope disassembly, the mitotic apparatus becomes encased by a discontinuous network of endoplasmic reticulum membranes, which associate with mitochondria, presumably to prevent their diffusion into the spindle area. We also observed a peculiar metaphase spindle organization. We found that kinetochores with attached k-fibers are almost invariably associated with lateral MT bundles that can be either interpolar bundles or k-fibers connected to a different kinetochore. This spindle organization is likely to favor chromosome alignment at metaphase and subsequent segregation during anaphase., Conclusions: We discovered several previously unknown features of membrane and MT organization during S2 cell mitosis. The genetic determinants of these mitotic features can now be investigated, for instance by using an RNAi-based approach, which is particularly easy and efficient in S2 cells.

The Drosophila S2 tissue culture cells are a widely used system for studies on mitosis. S2 cells are particularly sensitive to gene silencing by RNA interference (RNAi), allowing targeted inactivation of mitotic genes. S2 cells are also well suited for high-resolution light microscopy analysis of mitosis in fixed cells, and can be easily immunostained to detect mitotic components. In addition, S2 cells are amenable to transformation with plasmid encoding fluorescently tagged mitotic proteins, allowing in vivo analysis of their behavior throughout cell division. However, S2 cells have not been widely used for transmission electron microscopy (TEM) analysis, which provides ultrastructural details on the morphology of the mitotic apparatus that cannot be obtained with high-resolution confocal microscopy. Here, we describe a simple method for the ultrastructural analysis of mitosis in Drosophila S2 cells. •Our method, which involves fixation and sectioning of a cell pellet, provides excellent preservation of mitotic structures and allows analysis of a higher number of mitotic divisions per sample, compared to correlative light-electron microscopy.•Dividing cells are randomly oriented within the pellet and are sectioned along different planes, providing all-around information on the structure of the mitotic apparatus.

We analyzed the pattern of spindle microtubule (MT) regrowth after cold- or colcemid-induced MT depolymerization in Drosophila S2 cells. Cold-induced MT disassembly at low temperature (–2 °C) destroyed kinetochore-driven MT regrowth without affecting astral MT formation. Conversely, colcemid-induced MT depolymerization strongly impaired centrosome-dependent MT nucleation, allowing kinetochore-driven MT regrowth. Collectively, these results indicate that the kinetochore- and the centrosome-mediated MT assembly pathways exploit molecular mechanisms that are at least in part different.

A comprehensive examination and treatment of 49 students aged 20-25 years diagnosed chronic generalized catarrhal gingivitis (CGCG) were held. Depending on the methods of treatment were created into two groups of observation. The main group comprised 24 patients who along with dental sanitation and treatment of gingivitis took the course of salt treatment for 17 days, as opposed to control group. Hygienic researches and mineralthcrapy were held in a special room (23.6 m2). equipped with sylvite blocks with a total reaction surface 5 m2, salt filters with air ducts filled with wooden plates with mineral fragments. The study of the effectiveness of a comprehensive treatment of young patients with CGCG allowsto gel an information of the positive impact of salt therapyon the clinical condition of marginal periodontal tissues and indeces of oral cavity local immunity. The main curative factorsforming the internal environment of silvinite structures are multicomponent highly dispersed salt aerosol with a defined particle size and aeroionization. Natural salts complex consisting of chlorides of potassium, sodium and magnesium has an anti-inflammatory and immuno-modulating effects.

In this study, we evaluated the force of the cilium on the foot sole of a medium-sized pond snail Lymnaea stagnalis, crawling up in the anaerobic water. It was found that there are 1.3 x 10(9) cilia on the foot sole, their force is 1.47 x 10(-6) W, the force of one cilium is 1.1 x 10(-15) W and the force of single ciliary beat is 1.1 x 10(-16) W.

The sole of crawling gastropods is a unique model for studying the function of smooth muscles and ciliated epithelium. The gastropod snail Lymnaea stagnalis glides over the substratum without visible muscular contraction in its sole; consequently, the gliding was thought to be due to sole cilia. However, we have shown that the sole muscles in Lymnaea are phasic smooth muscles. They contribute extensively to gliding rate, which is directly correlated with the sole length (longitudinal sole muscle tonus) that varies widely during gliding. Here, we show that the linear relationship between gliding rate and sole length in Lymnaea may be modified. Serotonin increases gliding rate and has no effect on sole length. Dopamine contracts the sole and, consequently, slows the gliding rate, while ergometrine (a blocker of dopamine receptors) relaxes the sole and increases gliding rate. These influences on locomotion rate and sole length are similar to those obtained earlier for Helix lucorum, in which the substances changed the number and contraction force of muscle cells involved in peristaltic locomotory waves. Taken together, the data obtained here for Lymnaea and earlier for Helix describe the fundamental mechanisms for controlling phasic smooth muscles.

Complex investigation and treatment has been realized on 127 patients aged from 27 to 45 years with chronic generalized periodontitis. Patients were divided into two groups. In the fist group (68 patients) complex treatment included course of balneopeloid therapy with irrigation of high mineralized natural water (sanatorium "Tumentransgas" chink №1-95, Ugorsk) followed by application of sapropel mud (the Pake lake). The second group (59 patients) received only conventional periodontal treatment. Positive effect of balneopeloid therapy was identified, which was reflected in stabilizations of pathological process in the periodontal tissues in 78% of patients, as well as changes in physical and chemical properties of the oral gluid. Also the number of periodontopahogenic germs of gingival pockets was decreased.

Prior behavioral and neurophysiological studies provide evidence that the nudibranch mollusk Tritonia orients to the earth's magnetic field. Earlier studies of electrophysiological responses in certain neurons of the brain to changing ambient magnetic fields suggest that although certain identified brain cells fire impulses when the ambient field is changed, these neuron somata and their central dentritic and axonal processes are themselves not primary magnetic receptors. Here, using semi-intact animal preparations from which the brain was removed, we recorded from peripheral nerve trunks. Using techniques to count spikes in individual nerves and separately also to identify, then count individual axonal spikes in extracellular records, we found both excitatory and inhibitory axonal responses elicited by changes in the direction of ambient earth strength magnetic fields. We found responses in nerves from many locations throughout the body and in axons innervating the body wall and rhinophores. Our results indicate that primary receptors for geomagnetism in Tritonia are not focally concentrated in any particular organ, but appear to be widely dispersed in the peripheral body tissues.

This study revises the mechanisms of ciliary locomotion and demonstrates muscular contribution to locomotion rate in Lymnaea stagnalis. L. stagnalis sticks to the substratum by the foot sole and moves smoothly with no visible contractions of the foot. A ciliated epithelium covering the sole is underlain by smooth muscle cells containing giant mitochondria. It is shown here that slow (basal) locomotor activity (measured as the flow rate of physiological saline over isolated sole) appears spontaneously or is induced by 10(-8)-10(-7) M 5-HT. 5-HT (10(-7)-10(-4) M) facilitates locomotor activity dose-dependently, and KCN (an inhibitor of mitochondrial respiration) decreases these effects to the basal level. 5-HT and KCN have no effect on the frequency of ciliary beat (stroboscopic measurements), and blockers of anaerobic glycolysis inhibit ciliary motility. Under anaerobic conditions locomotion of a snail is slow and insensitive to 5-HT in contrast to that in aerobic environments. It is concluded that glycolysis supplies energy to ciliated cells and respiration to sole muscle cells; 5-HT stimulates ciliary beating in an all-or-none fashion and muscular waves in a dose-dependent manner; cilia provide slow (basal) gliding, and locomotory rate up to 80% above the basal level is determined by muscular waves.

In awake cats sitting with the head restrained, scratching was evoked using stimulation of the ear. Cats scratched the shoulder area, consistently failing to reach the ear. Kinematics of the hind limb movements and the activity of ankle muscles, however, were similar to those reported earlier in unrestrained cats. The activity of single neurons in the hind limb representation of the motor cortex, including pyramidal tract neurons (PTNs), was examined. During the protraction stage of the scratch response, the activity in 35% of the neurons increased and in 50% decreased compared with rest. During the rhythmic stage, the motor cortex population activity was approximately two times higher compared with rest, because the activity of 53% of neurons increased and that of 33% decreased in this stage. The activity of 61% of neurons was modulated in the scratching rhythm. The average depth of frequency modulation was 12.1 +/- 5.3%, similar to that reported earlier for locomotion. The phases of activity of different neurons were approximately evenly distributed over the scratch cycle. There was no simple correlation between resting receptive field properties and the activity of neurons during the scratch response. We conclude that the motor cortex participates in both the protraction and the rhythmic stages of the scratch response.

We report here evidence that the pedal peptides (Peps) first discovered in mollusks may be neurotransmitters with a general role in control of molluscan somatic and visceral muscles. Using Tritonia peptide (TPep) antiserum we obtained morphological evidence for such a role in Helix aspersa. We localized 1,200-1,400 small and medium-sized (5-40 microm) TPep-IR neurons in the central nervous system of Helix and demonstrated the presence of these neurons in each ganglion. Many TPep-immunoreactive (IR) neurons were motoneurons that sent axons to almost all peripheral nerves. TPep-IR fibers innervated the foot, esophagus, hermaphroditic duct, optic tentacles, salivary gland, heart, and proximal and distal aorta. In peripheral tissues TPep-IR fiber ramifications were mostly associated with muscles and with ciliated epithelia. In addition, TPep-IR fibers were in the neuropil of the ganglia, the commissures, and the connectives, and they formed axosomatic terminals in the central nervous system. TPep-IR neurons were found in the esophagus and hermaphroditic duct and as sensory receptors in the bulb of the optic tentacles. These results from Helix, and those reported elsewhere from other mollusks, suggest a general involvement of TPep-like substances in control of muscle- and ciliary-driven motor activities, including perhaps their antecedent sensory and central axosomatic integrative activity., ((c) 2005 Wiley-Liss, Inc.)

The terrestrial snail Helix lucorum crawls using waves of muscular contraction (pedal waves) that spread along the sole of its foot. Crawling speed depends on wave generation frequency (step frequency) and the distance the snail moves forwards during each wave (step length). In a previous study, video recordings of a crawling snail showed that its sole length varied over a wide range and was directly correlated with mollusc speed. Speed depended on step length, which was directly related to sole length, rather than on step frequency, which remained rather constant. In the present study, the effects of dopamine, ergometrine (a blocker of dopamine receptors in molluscs) and serotonin injection on the linear relationship between sole length and locomotor speed in Helix lucorum were studied. In crawling snails, dopamine caused sole contraction, and locomotion slowed down or ceased. Ergometrine stimulated locomotion, which resembled rapid crawling with an extended sole, as observed under normal conditions. Serotonin stimulated locomotion and accelerated crawling significantly without causing changes in sole length. The acceleration of locomotion induced by serotonin injection was due to pedal wave (step) elongation. It is proposed that, during each locomotor episode, dopamine controls snail speed by regulating sole length, which determines the amplitude of contraction of the muscle cells involved in pedal waves and, as a result, step length; serotonin determines the basic step length and shifts the linear relationship between sole length and mollusc speed upwards along the axis of mollusc speed. The efficiency of the serotonergic system depends on the physiological state of the mollusc (e.g. that characteristic of summer or winter).

Both serotonin and the molluskan pedal neuropeptides (TPEPs) cause increased ciliary beating rate of cells of the foot epithelium of the nudibranch mollusk, Tritonia diomedea. Here we compared responses of the ciliated epithelium of the esophagus with that of the foot, and report fundamental differences. Serotonin reduces the ciliary transport rate of the esophagus. We find also that the serotonin driven inhibition of esophagus is blocked and the excitation of foot epithelium is reduced by the serotonin receptor blocker ketanserin. On the contrary, ergometrine completely blocked the serotonin effect in the esophagus, and does not block the serotonin effect in the foot. Neither the TPEP driven excitation of ciliated cells of the foot nor that of the esophagus is blocked by ketanserin and ergometrine. Clearly, serotonin and TPEP regulation of different ciliated epithelia involve different receptors. Thus, mechanisms of serotonin control of different ciliated epithelia in the same animal are apparently fundamentally different, and unlike responses in all previous reports, 5HT here inhibits a ciliated epihelium.

Under analysis are gastrointestinal complications (hemorrhage, perforation of the duodenum, acute pancreatitis) which were observed in 10 of 177 patients after aortocoronary bypass. Risk factors of these complications, their specific diagnosis, treatment and prophylactics are discussed.

Prior work in the nudibranch Tritonia diomedea indicated that certain identifiable pedal ganglion neurons (Pd5 and 6) innervating the foot synthesize three novel peptides (TPeps) that resemble Pedal peptide (Pep) identified in the sea hare Aplysia californica. We report here that when TPeps are applied directly to isolated ciliated patches of Tritonia diomedea foot epithelium, there is an increase in ciliary beating that normally drives locomotion. Exposure to TPeps also increases the ciliary beat frequency of cells isolated from the pedal epithelium, suggesting that the observed ciliomotor effects are direct and not mediated by intervening cells. Antibodies to TPep bind to specific cells of the brain and foot and to ciliated peripheral tissues in Tritonia diomedea and in the pulmonate gastropod Lymnaea stagnalis. We suggest, therefore, that TPeps may regulate the activity of ciliated cells responsible for pedal locomotion and other functions in gastropod molluscs.

A cluster of electrically interconnected neurosecretory cells (the 'white cells') involved in the control of reproductive behavior was identified in the right pleural ganglion of the marine mollusc, Clione limacina. Pleural ganglia also contain large neurons (PL1 and PL2) having no connections with each other and with the white cells. Most isolated white cells put into the simple unconditioned medium (50% L-15) adhered to the bottom of uncoated dishes and demonstrated neurite outgrowth for 7-10 days. If growing processes overlapped, the white cells formed electrical connections with each other, but they formed no connections with the PL1 and PL2 neurons. It is concluded that in the case which was under study cellular intrinsic properties were sufficient for the formation of 'correct' connections between neurones.

In pedal ganglia of mollusc Clione limacina the growth of axons was studied in motoneurons and interneurons after transections of the wing nerve or of the pedal comissure. Neurons were stained by Lucifer Yellow. In motoneurons, neurites grown both from the transected end of the axon and from the neuron soma spread to all nerve trunks of ipsi- and contralateral ganglia. After nerve transection in the whole mollusc, wing movements restored 10 days later. In interneurons, neurites branched within the pedal ganglion or spread into cerebral ganglia but they did not extend out peripheral nerve trunks. Thus, the patterns of neurite sprouting in moto- and interneurons are different.

The marine mollusc Clione limacina swims by making rhythmic movements (with a frequency of 1-5 Hz) of its two wings. Filming demonstrated that the wings perform oscillatory movements in the frontal plane of the animal. During both the upward and downward movements of the wing, its posterior edge lagged behind the anterior one, i.e. the wing plane was inclined in relation to the longitudinal axis of an animal. As a result of this inclination, the wing oscillations in the frontal plane produce a force directed forwards. In restrained animals with the body cavity opened (a whole-animal preparation), the wing position, electrical activity in the wing nerve and activity of two identified efferent neurons (1A and 2A) were recorded during locomotory wing movements. There were two bursts of activity in the wing nerve during the locomotory cycle, the first one corresponding to the excitation of efferent neurons controlling the wing elevation, and the second one, to the excitation of efferent neurons controlling the lowering of the wing. Neurons 1A and 2A fired reciprocally at the beginning of the phase of elevating and lowering the wing, respectively. During excitation of one of the neurons, an IPSP appeared in its antagonist. A pair of isolated pedal ganglia of Clione was capable of generating the locomotory rhythm ("fictitious swimming"). In fictitious swimming, as in actual swimming, there were two bursts of activity in the wing nerve per locomotory cycle, and the 1A and 2A neurons fired reciprocally. Homologous neurons from the left and right ganglia fired inphase.(ABSTRACT TRUNCATED AT 250 WORDS)

The activity of C3-C4 propriospinal neurons was recorded during fictitious forelimb locomotion in immobilized decerebrated cats with the spinal cord transected at the lower thoracic level. The discharge frequency of most neurons was rhythmically modulated in relation to the cycle of fictitious stepping in spite of the absence of any rhythmic signals from the limb receptors. Thus, the intraspinal mechanisms present a powerful input to the C3-C4 propriospinal neurons.

(1) Pinna stimulation evoked rhythmic oscillations in the spinal cord of the decerebrate curarized cat ("fictitious" scratch reflex). The role of different spinal segments in generation of these oscillations was studied. For this purpose, destruction of the grey matter of one or of several spinal segments was performed. Besides, different numbers of caudal segments were disconnected from the rest of the cord by cooling the lateral surface of the cord. ENGs muscle nerves and activity of spinal neurons were recorded. (2) Different parts of the lumbosacral spinal cord, i.e. the L3 and L4 segments disconnected from the caudal part of the cord as well as the isolated L5 segment, are capable of generating rhythmic oscillations with a frequency (3-4 Hz) typical of the scratch reflex. (3) Rhythmic activity of the more caudal segments (L6-S1) usually appears only provided the rostral segments (L3-L5) generate rhythmic oscillations. However, when the dorsal surface of the L6-S1 segments is cooled, pinna stimulation evokes rhythmic activity in these segments earlier than in the L3-L5 segments. (4) The hypothesis is advanced that the L3-L5 segments are the "leading" ones, i.e., they determine the rhythm of activity in the whole spinal hindlimb centre.

(1) The activity of neurons of the ventral spinocerebellar tract (VSCT) during scratching was studied in thalamic and decapitate cats. The neurons were identified antidromically either by stimulation of the hindlimb area in the anterior lobe of the cerebellum (in thalamic cats) or by stimulation of the contralateral ventrolateral funiculus of the spinal cord (in decapitate cats). The scratch reflex was elicited by stimulation of either the pinna (in thalamic cats) or the cervical spinal cord (in decapitate cats). In most experiments, animals were immobilized and the activity of VSCT neurons was recorded during fictitious scratching. (2) During both actual and fictitious scratching, the discharge of VSCT neurons was rhythmically modulated in relation with the scratch cycle: neurons fired in bursts separated with periods of silence. Phases of activity of different neurons were unevenly distributed over the scratch cycle: most neurons fired within the limits of the flexor phase of the cycle. (3) The firing pattern of VSCT neurons during fictitious scratching was similar to that during actual scratching. Therefore, rhythmical burst firing of VSCT neurons is determined mainly by central mechanisms and not by a rhythmical sensory input. (4) The firing pattern of VSCT neurons in decapitate cats was similar to that in thalamic cats. Therefore, rhythmical burst firing of VSCT neurons is determined mainly by the central spinal mechanism and not by supraspinal motor centers. (5) The VSCT neurons which fired in long bursts during the greater part of the flexor phase were usually activated during the latent period of scratching, while those firing later in the cycle were usually either inhibited or not affected during this period. (6) The antidromic response in most VSCT neurons could be evoked from a large number of points in the hindlimb area of the cerebellar anterior lobe, both in the vermis and in the pars intermedia. Due to such extensive branching of axons, each point of the cortex receives signals from neurons firing in different phases of the cycle. But axons of VSCT neurons firing in long bursts during the greater part of the flexor phase terminate more extensively in the pars intermedia, while axons of neurons firing later in the cycle terminate more extensively in the vermis. (7) The functioning of the VSCT is essentially similar to that of the spino-reticulocerebellar pathway (SRCP). Both pathways convey messages about activity of the central spinal mechanism generating the motor output pattern of scratching, but the VSCT is active mainly in the flexor phase of the scratch cycle and the SRCP in the extensor one. A hypothesis is advanced that these pathways monitor activity of different groups of spinal interneurons.

Activity of propriospinal neurons from the ventral horn of segments L4 and L3 was recorded during fictitious scratch reflex in decerebrated cats. Neurons were identified by their antidromic response to stimulation of the ventral surface of the L7 segment. Most neurons were not active during scratching. This finding suggests that this group of neurons does not participate in the control of motoneurons during the activity of intrinsic spinal networks but rather participates in the transmission of supraspinal commands to motoneurons.

The heart of the pteropodial mollusc Clione limacina is innervated by the median nerve arising from the left abdominal ganglion. Five neurons sending axons to the heart have been identified in the Clione central nervous system with retrograde cobalt or Lucifer yellow staining. Neuron H1 located in the left pedal ganglion evoked heart excitation. Three neurons H2-H4 located in the medial part of the left abdominal ganglion caused heart inhibition. Neuron H5 located in the caudal part of the left abdominal ganglion did not affect the heart. The activity of the efferent heart neurons was found to be related to the operation of the locomotor rhythm generator. Spontaneous or reflex suppression of the locomotor rhythm generation was accompanied by inhibition of neuron H1 and excitation of neurons H2-H4. Such behavior of the efferent heart neurons ensures a positive correlation between heart and locomotor activities in Clione limacina.

The isolated pedal ganglia of the pteropodial mollusc Clione limacina generate the locomotor activity. In 30% of the pedal ganglion preparations, the locomotor rhythm was not regular, i. e. the locomotor generator worked in "bursts". These "locomotor bursts" were caused by spontaneous activations of command neurons located in the pedal ganglia. Single neurons were extracted from such preparations with an intracellular microelectrode and then their somas were put into the initial place between the ganglion cells. 25% of the isolated neurons (9 out of 35) renewed the "locomotor bursts"-related changes in the activity after the insertion into the ganglion. Neurons, originally excited during "bursts", continued to be excited after isolation, while inhibited neurons continued to be inhibited. It follows, therefore, that the command neurons can act on the target cells in the absence of morphological synapses.

In previous work carried out on the isolated pedal ganglia of the pteropod mollusc Clione limacina we described the activity of a neuronal element (type 12 neuron) and looked into its role in the locomotor rhythm generation (Arshavasky et al. 1985d). As we learned subsequently, the activity was recorded from the neuron axon passing in the pedal ganglia, while the neuron soma was located in the pleural ganglia and consequently was cut off in the course of pedal ganglia isolation. It thus became necessary to reinvestigate the properties of this neuron and its role in locomotory rhythm generation by using less reduced preparation of the central nervous system. The following results were obtained. (1) Each pleural ganglion contains only one neuron of this type, this cell is thus to be considered as the identified neuron. The neuron's axon reaches into the pedal ganglion via the pleuro-pedal connective. Then the axon divides into two branches terminating in the lateral regions of both pedal ganglia. The neurons 12 from the left and right pleural ganglia have no direct connections with one another; their synchronous operation in the locomotor cycle is determined by common inputs. (2) The electrical properties of an intact neuron 12 and one without a soma are about the same. In either case the neuron generates "plateau" potentials, i.e., it may persist for a long time in the depolarized state. Plateau potentials can be induced by a depolarizing current pulse or by an EPSP, and terminated by hyperpolarizing current or by an IPSP. The neuron input resistance drops about twofold during generation of the plateau potential.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurons whose excitation affected the locomotory rhythm were recorded in the isolated pedal ganglia of the marine mollusc Clione limacina. Some of these neurons generated "plateau" potentials, i.e. they remained depolarized for a long period after termination of the initial depolarizing current. A role of the command neurons in the motor behaviour of Clione is discussed.

(1) Signals transmitted to the cerebellum by the spino-reticulocerebellar pathway (SRCP) during scratching were studied. For this purpose, the activity of neurons of the lateral reticular nucleus (LRN), which are the last-order neurons of the SRCP, was recorded during scratching in thalamic cats. Scratching was evoked by stimulation of the pinna. LRN neurons were identified antidromically by stimulation of the hindlimb area in the cerebellar anterior lobe. In most experiments, animals were immobilized with Flaxedil, and stimulation of the pinna resulted in fictitious scratching, i.e., in periodical reciprocal activity of flexor and extensor motoneurons typical of actual scratching. (2) During both actual and fictitious scratching, the discharge frequency of LRN neurons was rhythmically modulated in relation with the scratch cycle. Most LRN neurons fired in short high-frequency bursts of spikes which coincided (completely or partly) with the extensor phase of the cycle. In this respect the SRCP differs from the ventral spinocerebellar tract (VSCT) which is maximally active in the flexor phase of the cycle. (3) The firing pattern of LRN neurons during fictitious scratching was similar to that during actual scratching. Therefore, the rhythmical burst firing of LRN neurons is determined mainly by the central mechanisms and not by the rhythmical sensory input. (4) Rhythmical modulation of LRN neurons disappeared after transection of the ipsilateral lateral funiculus of the spinal cord in which spinoreticular fibers are located. On the other hand, considerable reduction of rhythmical activity in descending brainstem-spinal pathways after contralateral hemisection of the spinal cord did not affect the discharge pattern of LRN neurons. These two facts indicate that the SRCP conveys mainly messages about activity of the central spinal mechanisms, and that influences of supraspinal motor centers.on LRN neurons and on spinoreticular neurons are of minor importance. (5) Axonal terminations of LRN neurons are distributed rather evenly over the hindlimb area in the anterior lobe of the cerebellum. Therefore, messages about the events, which happen within the spinal cord in the vicinity of the extensor phase of the cycle, arrive at every point of the hindlimb area.