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Sample records for aplysia

  1. Developmental transcriptome of Aplysia californica'

    KAUST Repository

    Heyland, Andreas

    2010-12-06

    Genome-wide transcriptional changes in development provide important insight into mechanisms underlying growth, differentiation, and patterning. However, such large-scale developmental studies have been limited to a few representatives of Ecdysozoans and Chordates. Here, we characterize transcriptomes of embryonic, larval, and metamorphic development in the marine mollusc Aplysia californica and reveal novel molecular components associated with life history transitions. Specifically, we identify more than 20 signal peptides, putative hormones, and transcription factors in association with early development and metamorphic stages-many of which seem to be evolutionarily conserved elements of signal transduction pathways. We also characterize genes related to biomineralization-a critical process of molluscan development. In summary, our experiment provides the first large-scale survey of gene expression in mollusc development, and complements previous studies on the regulatory mechanisms underlying body plan patterning and the formation of larval and juvenile structures. This study serves as a resource for further functional annotation of transcripts and genes in Aplysia, specifically and molluscs in general. A comparison of the Aplysia developmental transcriptome with similar studies in the zebra fish Danio rerio, the fruit fly Drosophila melanogaster, the nematode Caenorhabditis elegans, and other studies on molluscs suggests an overall highly divergent pattern of gene regulatory mechanisms that are likely a consequence of the different developmental modes of these organisms. © 2010 Wiley-Liss, Inc., A Wiley Company.

  2. Neuronal Transcriptome of Aplysia: Neuronal Compartments and Circuitry

    OpenAIRE

    Moroz, Leonid L.; Edwards, John R.; Puthanveettil, Sathyanarayanan V.; Kohn, Andrea B.; Ha, Thomas; Heyland, Andreas; Knudsen, Bjarne; Sahni, Anuj; Yu, Fahong; Liu, Li; Jezzini, Sami; LOVELL, PETER; Iannucculli, William; Chen, Minchen; Nguyen, Tuan

    2006-01-01

    Molecular analyses of Aplysia, a well-established model organism for cellular and systems neural science, have been seriously handicapped by a lack of adequate genomic information. By sequencing cDNA libraries from the central nervous system (CNS), we have identified over 175,000 expressed sequence tags (ESTs), of which 19,814 are unique neuronal gene products and represent 50%–70% of the total Aplysia neuronal transcriptome. We have characterized the transcriptome at three levels: (1) the ce...

  3. Circadian modulation of complex learning in diurnal and nocturnal Aplysia

    OpenAIRE

    Lyons, Lisa C.; Rawashdeh, Oliver; Katzoff, Ayelet; Susswein, Abraham J.; Eskin, Arnold

    2005-01-01

    Understanding modulation of memory, as well as the mechanisms underlying memory formation, has become a key issue in neuroscience research. Previously, we found that the formation of long-term, but not short-term, memory for a nonassociative form of learning, sensitization, was modulated by the circadian clock in the diurnal Aplysia californica. To define the scope of circadian modulation of memory, we examined an associative operant learning paradigm, learning that food is inedible (LFI). Si...

  4. Branch-specific heterosynaptic facilitation in Aplysia siphon sensory cells

    OpenAIRE

    Clark, Gregory A.; Kandel, Eric R.

    1984-01-01

    Aplysia siphon sensory cells exhibit heterosynaptic facilitation of transmitter release during both sensitization and classical conditioning of the siphon withdrawal response. In the present study, we asked whether facilitation must invariably enhance transmission at all terminals of a neuron or whether facilitation can instead occur at one set of terminals without also occurring at other terminals of the same cell. To examine this question, we compared effects of local application of seroton...

  5. Functional Neuroanatomy of the Rhinophore of Aplysia punctata

    OpenAIRE

    Rössler Wolfgang; Wertz Adrian; Obermayer Malu; Bickmeyer Ulf

    2006-01-01

    Abstract Background For marine snails, olfaction represents a crucial sensory modality for long-distance reception, as auditory and visual information is limited. The posterior tentacle of Aplysia, the rhinophore, is a chemosensory organ and several behavioural studies showed that the rhinophores can detect pheromones, initiate orientation and locomotion toward food. However the functional neuroanatomy of the rhinophore is not yet clear. Here we apply serotonin-immunohistochemistry and fluore...

  6. Neurogenesis in Aplysia californica resembles nervous system formation in vertebrates

    International Nuclear Information System (INIS)

    The pattern of neurogenesis of the central nervous system of Aplysia californica was investigated by [3H]thymidine autoradiography. Large numbers of animals at a series of early developmental stages were labeled with [3H]thymidine for 24 or 48 hr and were subsequently sampled at specific intervals throughout the life cycle. I found that proliferative zones, consisting of columnar and placodal ectodermal cells, are established in regions of the body wall adjacent to underlying mesodermal cells. Mitosis in the proliferative zones generates a population of cells which leave the surface and migrate inward to join the nearby forming ganglia. Tracing specific [3H]thymidine-labeled cells from the body wall to a particular ganglion and within the ganglion over time suggests that the final genomic replication of the neuronal precursors occurs before the cells join the ganglion while glial cell precursors and differentiating glial cells continue to divide within the ganglion for some time. Ultrastructural examination of the morphological features of the few mitosing cells observed within the Aplysia central nervous system supports this interpretation. The pattern of neurogenesis in the Aplysia central nervous system resembles the proliferation of cells in the neural tube and the migration of neural crest and ectodermal placode cells in the vertebrate nervous system but differs from the pattern described for other invertebrates

  7. Effects of Hypergravity on Statocyst Development in Embryonic Aplysia californica

    Science.gov (United States)

    Pedrozo, Hugo A.; Wiederhold, Michael L.

    1994-01-01

    Aplysia californica is a marine gastropod mollusc with bilaterally paired statocysts as gravity-reccptor organs. Data from three experiments in which embryonic Aplysia californica were exposed to 2 x g arc discussed. The experimental groups were exposed to excess gravity until hatching (9-12 day), whereas control groups were maintained at normal gravity. Body diameter was measured before exposure to 2 x g. Statocyst, statolith and body diameter were each determined for samples of 20 embryos from each group on successive days. Exposure to excess gravity led to an increase in body size. Statocyst size was not affected by exposure to 2 x g. Statolith size decreased with treatment as indicated by smaller statolith-to-body ratios observed in the 2 x g group in all three experiments. Mean statolith diameter was significantly smaller for the 2 x g group in Experiment 1 but not in Experiments 2 and 3. Defective statocysts, characterized by very small or no statoliths, were found in the 2 x g group in Experiments 1 and 2.

  8. Phylogeny of the sea hares in the aplysia clade based on mitochondrial DNA sequence data

    Energy Technology Data Exchange (ETDEWEB)

    Medina, Monica; Collins, Timothy; Walsh, Patrick J.

    2004-02-20

    Sea hare species within the Aplysia clade are distributed worldwide. Their phylogenetic and biogeographic relationships are, however, still poorly known. New molecular evidence is presented from a portion of the mitochondrial cytochrome oxidase c subunit 1 gene (cox1) that improves our understanding of the phylogeny of the group. Based on these data a preliminary discussion of the present distribution of sea hares in a biogeographic context is put forward. Our findings are consistent with only some aspects of the current taxonomy and nomenclatural changes are proposed. The first, is the use of a rank free classification for the different Aplysia clades and subclades as opposed to previously used genus and subgenus affiliations. The second, is the suggestion that Aplysia brasiliana (Rang, 1828) is a junior synonym of Aplysia fasciata (Poiret, 1789). The third, is the elimination of Neaplysia since its only member is confirmed to be part of the large Varria clade.

  9. Non-Ocular Circadian Oscillators and Photoreceptors Modulate Long Term Memory Formation in Aplysia

    OpenAIRE

    Lyons, Lisa C.; Rawashdeh, Oliver; Eskin, Arnold

    2006-01-01

    In Aplysia californica, memory formation for long-term sensitization (LTS) and for a more complex type of associative learning, learning that food is inedible (LFI), is modulated by a circadian clock. For both types of learning, formation of long-term memory occurs during the day and significantly less during the night. Aplysia eyes contain a well-characterized circadian oscillator that is strongly coupled to the locomotor activity rhythm. Thus, the authors hypothesized that the ocular circad...

  10. Transcriptome analysis and identification of regulators for long-term plasticity in Aplysia kurodai

    OpenAIRE

    Lee, Yong-Seok; Choi, Sun-Lim; Kim, Tae-Hyung; LEE, Jin-A; Kim, Hyong Kyu; Kim, Hyoung; Jang, Deok-Jin; Jennifer J. Lee; Lee, Sunghoon; Sin, Gwang Sik; Kim, Chang-Bae; Suzuki, Yutaka; Sugano, Sumio; Kubo, Tai; Moroz, Leonid L.

    2008-01-01

    The marine mollusk Aplysia is a useful model organism for studying the cellular bases of behavior and plasticity. However, molecular studies of Aplysia have been limited by the lack of genomic information. Recently, a large scale characterization of neuronal transcripts was performed in A. californica. Here, we report the analysis of a parallel set of neuronal transcripts from a closely related species A. kurodai found in the northwestern Pacific. We collected 4,859 nonredundant sequences fro...

  11. Functional neuroanatomy of the rhinophore of Aplysia punctata

    Directory of Open Access Journals (Sweden)

    Rössler Wolfgang

    2006-04-01

    Full Text Available Abstract Background For marine snails, olfaction represents a crucial sensory modality for long-distance reception, as auditory and visual information is limited. The posterior tentacle of Aplysia, the rhinophore, is a chemosensory organ and several behavioural studies showed that the rhinophores can detect pheromones, initiate orientation and locomotion toward food. However the functional neuroanatomy of the rhinophore is not yet clear. Here we apply serotonin-immunohistochemistry and fluorescent markers in combination with confocal microscopy as well as optical recording techniques to elucidate the structure and function of the rhinophore of the sea slug Aplysia punctata. Results With anatomical techniques an overview of the neuroanatomical organization of the rhinophore is presented. Labelling with propidium iodide revealed one layer of cell nuclei in the sensory epithelium and densely packed cell nuclei beneath the groove of the rhinophore, which extends to about two third of the total length of the rhinophore. Serotonin immunoreactivity was found within the olfactory glomeruli underneath the epithelium as well as in the rhinophore ganglion. Retrograde tracing from the rhinophore ganglion with 4-(4-(dihexadecylaminostyryl-N-methylpyridinium iodide (DiA demonstrated the connection of glomeruli with the ganglion. Around 36 glomeruli (mean diameter 49 μm were counted in a single rhinophore. Fluorimetric measurements of intracellular Ca2+ levels using Fura-2 AM loading revealed Ca2+-responses within the rhinophore ganglion to stimulation with amino acids. Bath application of different amino acids revealed differential responses at different positions within the rhinophore ganglion. Conclusion Our neuroanatomical study revealed the number and position of glomeruli in the rhinophore and the rhinophore ganglion as processing stage of sensory information. Serotonin-immunoreactive processes were found extensively within the rhinophore, but was not

  12. Neurogenesis of cephalic sensory organs of Aplysia californica

    DEFF Research Database (Denmark)

    Wollesen, Tim; Wanninger, Andreas; Klussmann-Kolb, Annette

    2007-01-01

    The opisthobranch gastropod Aplysia californica serves as a model organism in experimental neurobiology because of its simple and well-known nervous system. However, its nervous periphery has been less intensely studied. We have reconstructed the ontogeny of the cephalic sensory organs (labial...... microscopy to analyze the ciliary distribution of these sensory epithelia. Labial tentacles and the lip develop during metamorphosis, whereas rhinophores appear significantly later, in stage 10 juveniles. Our study has revealed immunoreactivity against FMRFamides and serotonin in all major nerves. The common...... of conspicuous transient FMRFamide-like cell somata. We have further found two distinct populations of FMRFamide-positive cell somata located both subepidermally and in the inner regions of the cephalic sensory organs in juveniles. The latter population partly consists of sensory cells, suggesting an...

  13. Digestive Gland from Aplysia depilans Gmelin: Leads for Inflammation Treatment

    Directory of Open Access Journals (Sweden)

    Andreia P. Oliveira

    2015-08-01

    Full Text Available The exploitation of marine organisms for human nutritional and pharmaceutical purposes has revealed important chemical prototypes for the discovery of new drugs, stimulating compounds isolation and syntheses of new related compounds with biomedical application. Nowadays, it is well known that inflammatory processes are involved in many diseases and the interest in the search for marine natural products with anti-inflammatory potential has been increasing. The genus Aplysia belongs to the class Gastropoda, having a wide geographical distribution and including several species, commonly known as sea hares. Aplysia depilans Gmelin is usually found in the Mediterranean Sea and in the Atlantic Ocean, from West Africa to the French coast. In these marine organisms, most of the digestion and nutrient absorption occurs in the digestive gland. This work aimed to explore the chemical composition and bioactivity of the methanol extract from A. depilans digestive gland. Therefore, fatty acids and carotenoids were determined by GC-MS and HPLC-DAD, respectively. Twenty-two fatty acids and eight carotenoids were identified for the first time in this species. The A. depilans digestive gland revealed to be essentially composed by polyunsaturated fatty acids (PUFA and xanthophylls. Regarding the anti-inflammatory potential in RAW 264.7 cells stimulated with lipopolysaccharide, it was observed that this matrix has capacity to reduce nitric oxide (NO and L-citrulline levels, which suggests that its compounds may act by interference with inducible nitric oxide synthase. Taking into account the results obtained, A. depilans digestive gland may be a good source of nutraceuticals, due to their richness in health beneficial nutrients, such as carotenoids and long-chain PUFA.

  14. Aging in Sensory and Motor Neurons Results in Learning Failure in Aplysia californica.

    Science.gov (United States)

    Kempsell, Andrew T; Fieber, Lynne A

    2015-01-01

    The physiological and molecular mechanisms of age-related memory loss are complicated by the complexity of vertebrate nervous systems. This study takes advantage of a simple neural model to investigate nervous system aging, focusing on changes in learning and memory in the form of behavioral sensitization in vivo and synaptic facilitation in vitro. The effect of aging on the tail withdrawal reflex (TWR) was studied in Aplysia californica at maturity and late in the annual lifecycle. We found that short-term sensitization in TWR was absent in aged Aplysia. This implied that the neuronal machinery governing nonassociative learning was compromised during aging. Synaptic plasticity in the form of short-term facilitation between tail sensory and motor neurons decreased during aging whether the sensitizing stimulus was tail shock or the heterosynaptic modulator serotonin (5-HT). Together, these results suggest that the cellular mechanisms governing behavioral sensitization are compromised during aging, thereby nearly eliminating sensitization in aged Aplysia. PMID:25970633

  15. Aging in Sensory and Motor Neurons Results in Learning Failure in Aplysia californica.

    Directory of Open Access Journals (Sweden)

    Andrew T Kempsell

    Full Text Available The physiological and molecular mechanisms of age-related memory loss are complicated by the complexity of vertebrate nervous systems. This study takes advantage of a simple neural model to investigate nervous system aging, focusing on changes in learning and memory in the form of behavioral sensitization in vivo and synaptic facilitation in vitro. The effect of aging on the tail withdrawal reflex (TWR was studied in Aplysia californica at maturity and late in the annual lifecycle. We found that short-term sensitization in TWR was absent in aged Aplysia. This implied that the neuronal machinery governing nonassociative learning was compromised during aging. Synaptic plasticity in the form of short-term facilitation between tail sensory and motor neurons decreased during aging whether the sensitizing stimulus was tail shock or the heterosynaptic modulator serotonin (5-HT. Together, these results suggest that the cellular mechanisms governing behavioral sensitization are compromised during aging, thereby nearly eliminating sensitization in aged Aplysia.

  16. PKG-Mediated MAPK Signaling Is Necessary for Long-Term Operant Memory in "Aplysia"

    Science.gov (United States)

    Michel, Maximilian; Green, Charity L.; Eskin, Arnold; Lyons, Lisa C.

    2011-01-01

    Signaling pathways necessary for memory formation, such as the mitogen-activated protein kinase (MAPK) pathway, appear highly conserved across species and paradigms. Learning that food is inedible (LFI) represents a robust form of associative, operant learning that induces short- (STM) and long-term memory (LTM) in "Aplysia." We investigated the…

  17. Dishabituation in "Aplysia" Can Involve Either Reversal of Habituation or Superimposed Sensitization

    Science.gov (United States)

    Kandel, Eric R.; Hawkins, Robert D.; Cohen, Tracey E.

    2006-01-01

    Dishabituation has been thought to be due either to reversal of the process of habituation or to a second process equivalent to sensitization superimposed on habituation. One way to address this question is by testing whether dishabituation and sensitization can be dissociated. Previous studies using this approach in "Aplysia" have come to…

  18. Serotonin- and Training-Induced Dynamic Regulation of CREB2 in "Aplysia"

    Science.gov (United States)

    Liu, Rong-Yu; Shah, Shreyansh; Cleary, Leonard J.; Byrne, John H.

    2011-01-01

    Long-term memory and plasticity, including long-term synaptic facilitation (LTF) of the "Aplysia" sensorimotor synapse, depend on the activation of transcription factors that regulate genes necessary for synaptic plasticity. In the present study we found that treatment with 5-HT and behavioral training produce biphasic changes in the expression of…

  19. Occurrence of the alien sea hare Aplysia dactylomela Rang, 1828 (Opisthobranchia, Aplysiidae in Malta

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    P.J. SCHEMBRI

    2012-12-01

    Full Text Available The alien sea hare Aplysia dactylomela, which is already established in several localities in the centraland eastern Mediterranean, is recorded for the first time from Malta on the basis of a specimen photographedat Cirkewwa (northern Malta. It is hypothesised that the occurrence of this species in Malta isa recent event and may be due to range expansion of the species.

  20. Neurons controlling Aplysia feeding inhibit themselves by continuous NO production.

    Directory of Open Access Journals (Sweden)

    Nimrod Miller

    Full Text Available BACKGROUND: Neural activity can be affected by nitric oxide (NO produced by spiking neurons. Can neural activity also be affected by NO produced in neurons in the absence of spiking? METHODOLOGY/PRINCIPAL FINDINGS: Applying an NO scavenger to quiescent Aplysia buccal ganglia initiated fictive feeding, indicating that NO production at rest inhibits feeding. The inhibition is in part via effects on neurons B31/B32, neurons initiating food consumption. Applying NO scavengers or nitric oxide synthase (NOS blockers to B31/B32 neurons cultured in isolation caused inactive neurons to depolarize and fire, indicating that B31/B32 produce NO tonically without action potentials, and tonic NO production contributes to the B31/B32 resting potentials. Guanylyl cyclase blockers also caused depolarization and firing, indicating that the cGMP second messenger cascade, presumably activated by the tonic presence of NO, contributes to the B31/B32 resting potential. Blocking NO while voltage-clamping revealed an inward leak current, indicating that NO prevents this current from depolarizing the neuron. Blocking nitrergic transmission had no effect on a number of other cultured, isolated neurons. However, treatment with NO blockers did excite cerebral ganglion neuron C-PR, a command-like neuron initiating food-finding behavior, both in situ, and when the neuron was cultured in isolation, indicating that this neuron also inhibits itself by producing NO at rest. CONCLUSION/SIGNIFICANCE: Self-inhibitory, tonic NO production is a novel mechanism for the modulation of neural activity. Localization of this mechanism to critical neurons in different ganglia controlling different aspects of a behavior provides a mechanism by which a humeral signal affecting background NO production, such as the NO precursor L-arginine, could control multiple aspects of the behavior.

  1. Characterization of small RNAs in Aplysia reveals a role for miR-124 in constraining synaptic plasticity through CREB

    OpenAIRE

    Rajasethupathy, Priyamvada; Fiumara, Ferdinando; Sheridan, Robert; Betel, Doron; Puthanveettil, Sathyanarayanan V.; Russo, James J.; Sander, Chris; Tuschl, Thomas; Kandel, Eric

    2009-01-01

    Memory storage and memory-related synaptic plasticity relies on precise spatiotemporal regulation of gene expression. To explore the role of small regulatory RNAs in learning-related synaptic plasticity we carried out massive parallel sequencing to profile the small RNAs of Aplysia californica. We identified 170 distinct miRNAs, 13 of which were novel and specific to Aplysia. Nine miRNAs were brain-enriched, and several of these were rapidly down-regulated by transient exposure to serotonin, ...

  2. Identification of a serotonin receptor coupled to adenylyl cyclase involved in learning-related heterosynaptic facilitation in Aplysia

    OpenAIRE

    Lee, Yong-Seok; Choi, Sun-Lim; Lee, Seung-Hee; Kim, Hyoung; Park, Hyungju; Lee, Nuribalhae; Lee, Sue-Hyun; Chae, Yeon-Su; Jang, Deok-Jin; Kandel, Eric R.; Kaang, Bong-Kiun

    2009-01-01

    Serotonin (5-HT) plays a critical role in modulating synaptic plasticity in the marine mollusc Aplysia and in the mammalian nervous system. In Aplysia sensory neurons, 5-HT can activate several signal cascades, including PKA and PKC, presumably via distinct types of G protein-coupled receptors. However, the molecular identities of these receptors have not yet been identified. We here report the cloning and functional characterization of a 5-HT receptor that is positively coupled to adenylyl c...

  3. Using an Aplysia Two-Hybrid System to Examine the Interactions Between Transcription Factors Involved in Long-Term Facilitation in the Nervous System of Aplysia

    OpenAIRE

    Choi, Jung-Hwan; LEE, Jin-A; Yim, Seok-Won; Lim, Chae-Seok; Lee, Chi-Hoon; Lee, Young-Don; Bartsch, Dusan; Kandel, Eric R.; Kaang, Bong-Kiun

    2003-01-01

    Interactions between ApCREB1a, ApCREB2, and ApC/EBP have been studied using conventional methods such as the yeast two-hybrid system. However, it is unclear whether these memory-related transcription factors actually interact in the native environment in neurons. To clarify this question, we have developed an Aplysia two-hybrid system and found, consistent with previous studies that ApCREB2 interacts with ApCREB1a and ApC/EBP, and that ApC/EBP forms homodimers. We have also found that ApCREB1...

  4. Nonassociative and associative modification of head-waving produced by aversive tentacular stimuli in Aplysia.

    Science.gov (United States)

    Fitzgerald, K K; Takacs, C A; Carew, T J

    1997-01-01

    Head-waving, a spontaneously occurring exploratory and appetitive behavior of the marine mollusc Aplysia, provides an opportunity to examine mechanisms of learning expressed in a nonreflexive behavior. The present study explores nonassociative and associative forms of learned modification of head-waving produced using an aversive stimulus as reinforcement. Experiments on intact, freely behaving animals demonstrate that training with electric shock as an aversive unconditioned stimulus, delivered unilaterally to the anterior tentacles, produces a learned shift in head-waving behavior away from the side on which shock was applied. This behavioral change is a novel learned behavioral response that is influenced by the topographic location of an aversive stimulus. Furthermore, training with application of tentacle shock reinforcement, contingent upon the animal's head position, produces operant conditioning of head-waving. Thus, anterior tentacle shock is effective as an aversive reinforcer for both nonassociative and operant learning expressed in the head-waving behavior of Aplysia. PMID:10456104

  5. Characterization, localization and function of pertussis toxin-sensitive G proteins in the nervous systems of Aplysia and Loligo

    International Nuclear Information System (INIS)

    The author has characterized pertussis toxin-sensitive G proteins in the nervous systems of the gastropod mollusc Aplysia and the cephalopod Loligo using [32P]ADP-ribosylation and immunoblotting with G protein specific antisera. As in vertebrates, this class of G protein is associated with membranes and enriched in nervous tissue in Aplysia. Analysis of dissected Aplysia ganglia reveal that it is enriched in neuropil, a region containing most of the central nervous system synapses. Because both Aplysia and Loligo synaptosomes are enriched in pertussis toxin-sensitive G proteins, it is likely that they are found in synaptic terminals. Fractionation of Aplysia synaptosomes into membrane and vesicle fractions reveals that, although the majority of G protein is recovered in the plasma membrane fraction, a small proportion is recovered in the vesicle fraction. He shows that G proteins are on intracellular membranes by ADP-ribosylating extruded axoplasm with pertussis toxin. A plausible explanation for vesicular localization of G protein in axoplasm is that G proteins are transported to terminals on vesicles. He has shown, using ligature experiments with Aplysia connectives and temperature block experiments in the giant axon of Loligo, that G proteins move by anterograde fast axonal transport. Injection of pertussis toxin into the identified Aplysia neuron L10 blocks histamine-induced presynaptic inhibition of transmitter release. This suggests that pertussis toxin sensitive G proteins play a role in modulating transmitter release at synaptic terminals. In the giant synapse of Loligo, he presents preliminary data that demonstrates that the activation of G proteins in the presynaptic terminal results in decreased transmitter release

  6. Associative conditioning analog selectively increases cAMP levels of tail sensory neurons in Aplysia.

    OpenAIRE

    Ocorr, K A; Walters, E T; Byrne, J H

    1985-01-01

    Bilateral clusters of sensory neurons in the pleural ganglia of Aplysia contain cells involved in a defensive tail withdrawal reflex. These cells exhibit heterosynaptic facilitation in response to noxious skin stimulation that can be mimicked by the application of serotonin. Recently it has been shown that this facilitation can be selectively amplified by the application of a classical conditioning procedure to individual sensory neurons. We now report that an analog of this classical conditi...

  7. Aplysia synapse associated protein (APSAP): identification, characterization, and selective interactions with Shaker-type potassium channels

    OpenAIRE

    Reissner, Kathryn J.; Boyle, Heather D.; Ye, Xiaojing; Carew, Thomas J.

    2007-01-01

    The vertebrate post-synaptic density (PSD) is a region of high molecular complexity in which dynamic protein interactions modulate receptor localization and synaptic function. Members of the membrane-associated guanylate kinase (MAGUK) family of proteins represent a major structural and functional component of the vertebrate PSD. In order to investigate the expression and significance of orthologous PSD components associated with the Aplysia sensory neuron-motor neuron synapse, we have cloned...

  8. Transcriptional analysis of a whole-body form of long-term habituation in Aplysia californica

    OpenAIRE

    Holmes, Geraldine; Herdegen, Samantha; Schuon, Jonathan; Cyriac, Ashly; Lass, Jamie; Conte, Catherine; Calin-Jageman, Irina E.; Calin-Jageman, Robert J.

    2015-01-01

    Habituation is the simplest form of learning, but we know little about the transcriptional mechanisms that encode long-term habituation memory. A key obstacle is that habituation is relatively stimulus-specific and is thus encoded in small sets of neurons, providing poor signal/noise ratios for transcriptional analysis. To overcome this obstacle, we have developed a protocol for producing whole-body long-term habituation of the siphon-withdrawal reflex (SWR) of Aplysia californica. Specifical...

  9. A presynaptic role for FMRP during protein synthesis–dependent long-term plasticity in Aplysia

    OpenAIRE

    Till, Sally M.; Li, Hsiu-Ling; Miniaci, Maria Concetta; Kandel, Eric R.; Choi, Yun-Beom

    2011-01-01

    Loss of the Fragile X mental retardation protein (FMRP) is associated with presumed postsynaptic deficits in mouse models of Fragile X syndrome. However, the possible presynaptic roles of FMRP in learning-related plasticity have received little attention. As a result, the mechanisms whereby FMRP influences synaptic function remain poorly understood. To investigate the cellular locus of the effects of FMRP on synaptic plasticity, we cloned the Aplysia homolog of FMRP and find it to be highly e...

  10. A Single Aplysia Neurotrophin Mediates Synaptic Facilitation via Differentially Processed Isoforms

    OpenAIRE

    Stefan R. Kassabov; Yun-Beom Choi; Kevin A. Karl; Harshad D. Vishwasrao; Craig H. Bailey; Eric R. Kandel

    2013-01-01

    Neurotrophins control the development and adult plasticity of the vertebrate nervous system. Failure to identify invertebrate neurotrophin orthologs, however, has precluded studies in invertebrate models, limiting our understanding of fundamental aspects of neurotrophin biology and function. We identified a neurotrophin (ApNT) and Trk receptor (ApTrk) in the mollusk Aplysia and found that they play a central role in learning-related synaptic plasticity. Blocking ApTrk signaling impairs long-t...

  11. "Caged calcium" in Aplysia pacemaker neurons. Characterization of calcium-activated potassium and nonspecific cation currents

    OpenAIRE

    1989-01-01

    We have studied calcium-activated potassium current, IK(Ca), and calcium-activated nonspecific cation current, INS(Ca), in Aplysia bursting pacemaker neurons, using photolysis of a calcium chelator (nitr-5 or nitr-7) to release "caged calcium" intracellularly. A computer model of nitr photolysis, multiple buffer equilibration, and active calcium extrusion was developed to predict volume-average and front-surface calcium concentration transients. Changes in arsenazo III absorbance were used to...

  12. Measurement of nonuniform current densities and current kinetics in Aplysia neurons using a large patch method.

    OpenAIRE

    Johnson, J W; Thompson, S.

    1989-01-01

    A large patch electrode was used to measure local currents from the cell bodies of Aplysia neurons that were voltage-clamped by a two-microelectrode method. Patch currents recorded at the soma cap, antipodal to the origin of the axon, and whole-cell currents were recorded simultaneously and normalized to membrane capacitance. The patch electrode could be reused and moved to different locations which allowed currents from adjacent patches on a single cell to be compared. The results show that ...

  13. Biomineralization in the Sea Hare Aplysia punctata Initiated by Nano-Dolomite

    OpenAIRE

    Tonejc, Anđelka; Medaković, Davorin; Popović, Stanko; JAKLIN Andrej; Bijelić, Mirjana; Lončarek, Ivana

    2014-01-01

    X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM), environmental scanning electron microscopy (ESEM) and energy dispersive X-ray analysis (EDS) were used in study of starting biomineralization processes in embryos of the sea hare species Aplysia punctata. 10 days old embryos appeared amorphous according to XRD patterns. TEM of the same sample showed that first grains of nanocryst...

  14. mtDNA ribosomal gene phylogeny of sea hares in the genus Aplysia (Gastropoda, Opisthobranchia, Anaspidea): Implications for comparative neurobiology

    Energy Technology Data Exchange (ETDEWEB)

    Medina, Monica; Collins, Timothy M.; Walsh, Patrick J.

    2000-08-10

    Sea hares within the genus Aplysia are important neurobiological model organisms, and as studies based on different Aplysia species appear in the literature, a phylogenetic framework has become essential. We present a phylogenetic hypothesis for this genus, based on portions of two mitochondrial genes (12S and 16S). In addition, we reconstruct the evolution of several behavioral characters of interest to neurobiologists in order to illustrate the potential benefits of a phylogeny for the genus Aplysia. These benefits include the determination of ancestral traits, the direction and timing of evolution of characters, prediction of the distribution of traits, and identification of cases of independent acquisition of traits within lineages. This last benefit may prove especially useful in understanding the linkage between behaviors and their underlying neurological basis.

  15. mtDNA ribosomal gene phylogeny of sea hares in the genus Aplysia (Gastropoda, Opisthobranchia, Anaspidea): implications for comparative neurobiology.

    Science.gov (United States)

    Medina, M; Collins, T M; Walsh, P J

    2001-01-01

    Sea hares within the genus Aplysia are important neurobiological model organisms; as more studies based on different Aplysia species are appearing in the literature, a phylogenetic framework has become essential. We present a phylogenetic hypothesis for this genus, based on portions of two mitochondrial genes (12S and 16S). In addition, we reconstruct the evolution of several behavioral characters of interest to neurobiologists to illustrate the potential benefits of a phylogeny for the genus Aplysia. These benefits include determination of ancestral traits, direction and timing of evolution of characters, prediction of the distribution of traits, and identification of cases of independent acquisition of traits within lineages. This last benefit may prove especially useful in understanding the linkage between behaviors and their underlying neurological bases. PMID:12116938

  16. Multiple Memory Processes Following Training That a Food Is Inedible in Aplysia

    OpenAIRE

    Botzer, Dina; Markovich, Silvia; Susswein, Abraham J.

    1998-01-01

    In many organisms, memory after training can be separated into a number of processes. We now report that separable memory processes are also initiated by a training procedure affecting Aplysia feeding behavior, a model system for examining the neural mechanisms underlying the regulation of a complex behavior. Four distinct memory process were identified: (1) a very short-term memory that declines within 15 min, (2) a short-term memory that persists for 0.5–1.0 hr, (3) an intermediate-term mem...

  17. In search of general mechanisms for long-lasting plasticity: Aplysia and the hippocampus.

    OpenAIRE

    Pittenger, Christopher; Kandel, Eric R.

    2003-01-01

    Long-term synaptic plasticity is thought to underlie many forms of long-lasting memory. Long-lasting plasticity has been most extensively studied in the marine snail Aplysia and in the mammalian hippocampus, where Bliss and Lømo first described long-term potentiation 30 years ago. The molecular mechanisms of plasticity in these two systems have proven to have many similarities. Here, we briefly describe some of these areas of overlap. We then summarize recent advances in our understanding of ...

  18. Calcium-Activated Proteases Are Critical for Refilling Depleted Vesicle Stores in Cultured Sensory-Motor Synapses of "Aplysia"

    Science.gov (United States)

    Khoutorsky, Arkady; Spira, Micha E.

    2005-01-01

    "Aplysia" motoneurons cocultured with a presynaptic sensory neuron exhibit homosynaptic depression when stimulated at low frequencies. A single bath application of serotonin (5HT) leads within seconds to facilitation of the depressed synapse. The facilitation is attributed to mobilization of neurotransmitter-containing vesicles from a feeding…

  19. PKA and PKC Are Required for Long-Term but Not Short-Term in Vivo Operant Memory in "Aplysia"

    Science.gov (United States)

    Michel, Maximilian; Green, Charity L.; Lyons, Lisa C.

    2011-01-01

    We investigated the involvement of PKA and PKC signaling in a negatively reinforced operant learning paradigm in "Aplysia", learning that food is inedible (LFI). In vivo injection of PKA or PKC inhibitors blocked long-term LFI memory formation. Moreover, a persistent phase of PKA activity, although not PKC activity, was necessary for long-term…

  20. Localization of Molecular Correlates of Memory Consolidation to Buccal Ganglia Mechanoafferent Neurons after Learning that Food Is Inedible in "Aplysia"

    Science.gov (United States)

    Levitan, David; Saada-Madar, Ravit; Teplinsky, Anastasiya; Susswein, Abraham J.

    2012-01-01

    Training paradigms affecting "Aplysia" withdrawal reflexes cause changes in gene expression leading to long-term memory formation in primary mechanoafferents that initiate withdrawal. Similar mechanoafferents are also found in the buccal ganglia that control feeding behavior, raising the possibility that these mechanoafferents are a locus of…

  1. Nitric Oxide and Histamine Signal Attempts to Swallow: A Component of Learning that Food Is Inedible in "Aplysia"

    Science.gov (United States)

    Katzoff, Ayelet; Miller, Nimrod; Susswein, Abraham J.

    2010-01-01

    Memory that food is inedible in "Aplysia" arises from training requiring three contingent events. Nitric oxide (NO) and histamine are released by a neuron responding to one of these events, attempts to swallow food. Since NO release during training is necessary for subsequent memory and NO substitutes for attempts to swallow, it was suggested that…

  2. Role of "Aplysia" Cell Adhesion Molecules during 5-HT-Induced Long-Term Functional and Structural Changes

    Science.gov (United States)

    Han, Jin-Hee; Lim, Chae-Seok; Lee, Yong-Seok; Kandel, Eric R.; Kaang, Bong-Kiun

    2004-01-01

    We previously reported that five repeated pulses of 5-HT lead to down-regulation of the TM-apCAM isoform at the surface of "Aplysia" sensory neurons (SNs). We here examined whether apCAM down-regulation is required for 5-HT-induced long-term facilitation. We also analyzed the role of the cytoplasmic and extracellular domains by overexpressing…

  3. Effects of Aversive Stimuli beyond Defensive Neural Circuits: Reduced Excitability in an Identified Neuron Critical for Feeding in "Aplysia"

    Science.gov (United States)

    Shields-Johnson, Maria E.; Hernandez, John S.; Torno, Cody; Adams, Katherine M.; Wainwright, Marcy L.; Mozzachiodi, Riccardo

    2013-01-01

    In "Aplysia," repeated trials of aversive stimuli produce long-term sensitization (LTS) of defensive reflexes and suppression of feeding. Whereas the cellular underpinnings of LTS have been characterized, the mechanisms of feeding suppression remained unknown. Here, we report that LTS training induced a long-term decrease in the excitability of…

  4. Possible Contributions of a Novel Form of Synaptic Plasticity in "Aplysia" to Reward, Memory, and Their Dysfunctions in Mammalian Brain

    Science.gov (United States)

    Hawkins, Robert D.

    2013-01-01

    Recent studies in "Aplysia" have identified a new variation of synaptic plasticity in which modulatory transmitters enhance spontaneous release of glutamate, which then acts on postsynaptic receptors to recruit mechanisms of intermediate- and long-term plasticity. In this review I suggest the hypothesis that similar plasticity occurs in…

  5. Characterization of glycolipids synthesized in an identified neuron of Aplysia californica

    International Nuclear Information System (INIS)

    Because radioactive precursors can be injected directly into the cell body or axon of R2, a giant, identified neuron of the Aplysia abdominal ganglion, it was possible to show that glycolipid is synthesized in the cell body, inserted into membranes along with glycoprotein, and then exported into the axon within organelles that are moved by fast axonal transport. After intrasomatic injection of N-[3H]-acetyl-D-galactosamine, five major 3H-glycolipids were identified using thin layer polysilicic acid glass fiber chromatography. At least two of the lipids are negatively charged. Analysis of 32P-labeled lipid from the abdominal ganglion revealed the presence of 2-aminoethylphosphonate, indicating that these polar substances are sphingophosphonoglycolipids. The major 3H-glycolipids synthesized in R2 are similar to a family of phospholipids isolated from the skin of A. kurodai. Since sialic acid is absent in Aplysia as in other invertebrates, these polar glycolipids may function like gangliosides in vertebrates. The polar 3H-glycolipids are synthesized and incorporated into intracytoplasmic membranes solely in the cell body. Direct injection of the labeled sugar into the axon revealed no local synthesis or exchange of glycolipid. Moreover, there was no indication for transfer from glial cells into axoplasm. Although the incorporation of N-[3H]-acetyl-D-galactosamine into glycolipid is not affected by anisomycin, an effective inhibitor of protein synthesis, the export into the axon of membranes containing the newly synthesized lipid is completely blocked by the drug

  6. Development of the Statocyst in Aplysia Californica. Part 1; Observations on Statoconial Development

    Science.gov (United States)

    Wiederhold, Michael L.; Sharma, Jyotsna S.; Driscoll, Brian P.; Harrison, Jeffrey L.

    1990-01-01

    The gravity receptor organs of gastropod molluscs, such as Aplysia californica, are bilateral paired statocysts, which contain dense statoconia within a fluid-filled cyst. Gravitational forces on the statoconia are sensed through their interaction with ciliated mechanoreceptor cells in the wall of the cyst. Larval Aplysia contain a single statolith within each statocyst; when the animals grow to a critical size, they begin producing multiple statoconia, a process that continues throughout life. The number of statoconia is highly correlated with animal weight but poorly correlated with age, indicating that stone production is related to total metabolism. The single statolith has an amorphous internal structure whereas the multiple statoconia have calcification deposited on concentric layers of membrane or matrix protein. The statolith appears to be produced within the cyst lumen but the multiple statoconia are produced within supporting cells between the receptor cells. Large adult animals have statoconia larger than those in early post-metamorphic animals which have just started producing multiple stones. The maximum statocyst diameter at which the receptor-cell cilia can suspend the statolith in the center of the cyst lumen is 45 micrometers; production of multiple stones begins when the cyst reaches this size. The mechanisms by which statoconia production is initiated and controlled are discussed.

  7. Localization of GABA-like immunoreactivity in the central nervous system of Aplysia californica.

    Science.gov (United States)

    Díaz-Ríos, M; Suess, E; Miller, M W

    1999-10-18

    Gamma-aminobutyric acid (GABA) is present in the central nervous system of Aplysia californica (Gastropoda, Opisthobranchia) where its role as a neurotransmitter is supported by pharmacological, biochemical, and anatomical investigations. In this study, the distribution of GABA-immunoreactive (GABAi) neurons and fiber systems in Aplysia was examined by using wholemount immunohistochemistry and nerve backfill methods. GABAi neurons were located in the buccal, cerebral, and pedal ganglia. Major commissural fiber systems were present in each of these ganglia, whereas more limited fiber systems were observed in the ganglionic connectives. Some of the interganglionic fibers were found to originate from two unpaired GABAi neurons, one in the buccal ganglion and one in the right pedal ganglion, each of which exhibited bilateral projections. No GABAi fibers were found in the nerves that innervate peripheral sensory, motor, or visceral organs. Although GABAi cells were not observed in the pleural or abdominal ganglia, these ganglia did receive limited projections of GABAi fibers originating from neurons in the pedal ganglia. The distribution of GABAi neurons suggests that this transmitter system may be primarily involved in coordinating certain bilateral central pattern generator (CPG) systems related to feeding and locomotion. In addition, the presence of specific interganglionic GABAi projections also suggests a role in the regulation or coordination of circuits that produce components of complex behaviors. PMID:10524338

  8. Transcriptional regulation of long-term memory in the marine snail Aplysia

    Directory of Open Access Journals (Sweden)

    Lee Yong-Seok

    2008-06-01

    Full Text Available Abstract Whereas the induction of short-term memory involves only covalent modifications of constitutively expressed preexisting proteins, the formation of long-term memory requires gene expression, new RNA, and new protein synthesis. On the cellular level, transcriptional regulation is thought to be the starting point for a series of molecular steps necessary for both the initiation and maintenance of long-term synaptic facilitation (LTF. The core molecular features of transcriptional regulation involved in the long-term process are evolutionally conserved in Aplysia, Drosophila, and mouse, and indicate that gene regulation by the cyclic AMP response element binding protein (CREB acting in conjunction with different combinations of transcriptional factors is critical for the expression of many forms of long-term memory. In the marine snail Aplysia, the molecular mechanisms that underlie the storage of long-term memory have been extensively studied in the monosynaptic connections between identified sensory neuron and motor neurons of the gill-withdrawal reflex. One tail shock or one pulse of serotonin (5-HT, a modulatory transmitter released by tail shocks, produces a transient facilitation mediated by the cAMP-dependent protein kinase leading to covalent modifications in the sensory neurons that results in an enhancement of transmitter release and a strengthening of synaptic connections lasting minutes. By contrast, repeated pulses of 5-hydroxytryptamine (5-HT induce a transcription- and translation-dependent long-term facilitation (LTF lasting more than 24 h and trigger the activation of a family of transcription factors in the presynaptic sensory neurons including ApCREB1, ApCREB2 and ApC/EBP. In addition, we have recently identified novel transcription factors that modulate the expression of ApC/EBP and also are critically involved in LTF. In this review, we examine the roles of these transcription factors during consolidation of LTF induced

  9. Parallel somatic and synaptic processing in the induction of intermediate-term and long-term synaptic facilitation in Aplysia

    OpenAIRE

    Sherff, Carolyn M.; Carew, Thomas J.

    2004-01-01

    The induction of different phases of memory depends on the amount and patterning of training, raising the question of whether specific training patterns engage different cellular mechanisms and whether these mechanisms operate in series or in parallel. We examined these questions by using a cellular model of memory formation: facilitation of the tail sensory neuron-motor neuron synapses by serotonin (5-hydroxytryptamine, 5-HT) in the CNS of Aplysia. We studied facilitation in two temporal dom...

  10. PKA and PKC are required for long-term but not short-term in vivo operant memory in Aplysia

    OpenAIRE

    Michel, Maximilian; Green, Charity L.; Lyons, Lisa C.

    2011-01-01

    We investigated the involvement of PKA and PKC signaling in a negatively reinforced operant learning paradigm in Aplysia, learning that food is inedible (LFI). In vivo injection of PKA or PKC inhibitors blocked long-term LFI memory formation. Moreover, a persistent phase of PKA activity, although not PKC activity, was necessary for long-term memory. Surprisingly, neither PKA nor PKC activity was required for associative short-term LFI memory. Additionally, PKA and PKC were not required for th...

  11. Long-term memory in Aplysia modulates the total number of varicosities of single identified sensory neurons.

    OpenAIRE

    Bailey, C H; Chen, M.

    1988-01-01

    The morphological consequences of long-term habituation and sensitization of the gill withdrawal reflex in Aplysia california were explored by examining the total number of presynaptic varicosities of single identified sensory neurons (a critical site of plasticity for the biochemical and biophysical changes that underlie both types of learning) in control and behaviorally trained animals. Sensory neurons from habituated animals had 35% fewer synaptic varicosities than did sensory neurons fro...

  12. Spontaneous transmitter release recruits postsynaptic mechanisms of long-term and intermediate-term facilitation in Aplysia

    OpenAIRE

    Jin, Iksung; Udo, Hiroshi; Joseph B. Rayman; Puthanveettil, Sathya; Kandel, Eric R.; Hawkins, Robert D.

    2012-01-01

    Whereas short-term (minutes) facilitation at Aplysia sensory–motor neuron synapses is presynaptic, long-term (days) facilitation involves synaptic growth, which requires both presynaptic and postsynaptic mechanisms. How are the postsynaptic mechanisms recruited, and when does that process begin? We have been investigating the possible role of spontaneous transmitter release from the presynaptic neuron. In the previous paper, we found that spontaneous release is critical for the induction of l...

  13. A Single Aplysia Neurotrophin Mediates Synaptic Facilitation via Differentially Processed Isoforms Secreted as Mature or Precursor Forms

    OpenAIRE

    Kassabov, Stefan R.; Choi, Yun-Beom; Karl, Kevin A; Vishwasrao, Harshad D.; Bailey, Craig H.; Kandel, Eric R.

    2013-01-01

    Neurotrophins control the development and adult plasticity of the vertebrate nervous system. Failure to identify invertebrate neurotrophin orthologs, however, has precluded studies in invertebrate models, limiting understanding of fundamental aspects of neurotrophin biology and function. We identified a neurotrophin (ApNT) and Trk receptor (ApTrk) in the mollusk Aplysia and find they play a central role in learning related synaptic plasticity. ApNT increases the magnitude and lowers the thres...

  14. Training with Inedible Food in "Aplysia" Causes Expression of C/EBP in the Buccal but Not Cerebral Ganglion

    Science.gov (United States)

    Levitan, David; Lyons, Lisa C.; Perelman, Alexander; Green, Charity L.; Motro, Benny; Eskin, Arnold; Susswein, Abraham J.

    2008-01-01

    Training with inedible food in "Aplysia" increased expression of the transcription factor C/EBP in the buccal ganglia, which primarily have a motor function, but not in the cerebral or pleural ganglia. C/EBP mRNA increased immediately after training, as well as 1-2 h later. The increased expression of C/EBP protein lagged the increase in mRNA.…

  15. Neurexin-Neuroligin Trans-Synaptic Interaction Mediates Learning-Related Synaptic Remodeling and Long-Term Facilitation in Aplysia

    OpenAIRE

    Choi, Yun-Beom; Li, Hsiu-Ling; Kassabov, Stefan R.; Jin, Iksung; Puthanveettil, Sathyanarayanan V.; Karl, Kevin A; Lu, Yang; Kim, Joung-Hun; Bailey, Craig H.; Kandel, Eric R.

    2011-01-01

    Neurexin and neuroligin, which undergo heterophilic interactions with each other at the synapse, are mutated in some patients with autism spectrum disorder, a set of disorders characterized by deficits in social and emotional learning. We have explored the role of neurexin and neuroligin at sensory-to-motor neuron synapses of the gill-withdrawal reflex in Aplysia that undergoes sensitization, a simple form of learned fear. We find that depleting neurexin in the presynaptic sensory neuron or n...

  16. Gastropod arginine kinases from Cellana grata and Aplysia kurodai. Isolation and cDNA-derived amino acid sequences.

    Science.gov (United States)

    Suzuki, T; Inoue, N; Higashi, T; Mizobuchi, R; Sugimura, N; Yokouchi, K; Furukohri, T

    2000-12-01

    Arginine kinase (AK) was isolated from the radular muscle of the gastropod molluscs Cellana grata (subclass Prosobranchia) and Aplysia kurodai (subclass Opisthobranchia), respectively, by ammonium sulfate fractionation, Sephadex G-75 gel filtration and DEAE-ion exchange chromatography. The denatured relative molecular mass values were estimated to be 40 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isolated enzyme from Aplysia gave a Km value of 0.6 mM for arginine and a Vmax value of 13 micromole Pi min(-1) mg protein(-1) for the forward reaction. These values are comparable to other molluscan AKs. The cDNAs encoding Cellana and Aplysia AKs were amplified by polymerase chain reaction, and the nucleotide sequences of 1,608 and 1,239 bp, respectively, were determined. The open reading frame for Cellana AK is 1044 nucleotides in length and encodes a protein with 347 amino acid residues, and that for A. kurodai is 1077 nucleotides and 354 residues. The cDNA-derived amino acid sequences were validated by chemical sequencing of internal lysyl endopeptidase peptides. The amino acid sequences of Cellana and Aplysia AKs showed the highest percent identity (66-73%) with those of the abalone Nordotis and turbanshell Battilus belonging to the same class Gastropoda. These AK sequences still have a strong homology (63-71%) with that of the chiton Liolophura (class Polyplacophora), which is believed to be one of the most primitive molluscs. On the other hand, these AK sequences are less homologous (55-57%) with that of the clam Pseudocardium (class Bivalvia), suggesting that the biological position of the class Polyplacophora should be reconsidered. PMID:11281267

  17. Huntingtin Is Critical Both Pre- and Postsynaptically for Long-Term Learning-Related Synaptic Plasticity in Aplysia

    Science.gov (United States)

    Choi, Yun-Beom; Kadakkuzha, Beena M.; Liu, Xin-An; Akhmedov, Komolitdin; Kandel, Eric R.; Puthanveettil, Sathyanarayanan V.

    2014-01-01

    Patients with Huntington’s disease exhibit memory and cognitive deficits many years before manifesting motor disturbances. Similarly, several studies have shown that deficits in long-term synaptic plasticity, a cellular basis of memory formation and storage, occur well before motor disturbances in the hippocampus of the transgenic mouse models of Huntington’s disease. The autosomal dominant inheritance pattern of Huntington’s disease suggests the importance of the mutant protein, huntingtin, in pathogenesis of Huntington’s disease, but wild type huntingtin also has been shown to be important for neuronal functions such as axonal transport. Yet, the role of wild type huntingtin in long-term synaptic plasticity has not been investigated in detail. We identified a huntingtin homolog in the marine snail Aplysia, and find that similar to the expression pattern in mammalian brain, huntingtin is widely expressed in neurons and glial cells. Importantly the expression of mRNAs of huntingtin is upregulated by repeated applications of serotonin, a modulatory transmitter released during learning in Aplysia. Furthermore, we find that huntingtin expression levels are critical, not only in presynaptic sensory neurons, but also in the postsynaptic motor neurons for serotonin-induced long-term facilitation at the sensory-to-motor neuron synapse of the Aplysia gill-withdrawal reflex. These results suggest a key role for huntingtin in long-term memory storage. PMID:25054562

  18. Operant conditioning of head-waving in Aplysia. II. Contingent modification of electromyographic activity in identified muscles.

    Science.gov (United States)

    Cook, D G; Carew, T J

    1989-09-01

    Aplysia can readily exhibit operant conditioning of their head-waving response when bright light is used as aversive reinforcement (Cook and Carew, 1986). In the first paper of this series (Cook and Carew, 1989a), we showed that the electromyographic (EMG) activity of a discrete band of neck muscles, the lateral columellar muscles (LCMs) of Aplysia is significantly correlated with the component of head-waving (the horizontal component) that is modified during operant conditioning. In the present paper, we asked whether the EMG activity of the LCMs themselves could also be contingently modified, using the same procedures that produce operant conditioning of the behavioral response. Differential EMG from the LCMs was recorded in freely behaving animals with chronically implanted muscle cuff electrodes. Animals receiving aversive reinforcement (bright light) that was contingent upon specific patterns of LCM activity readily learned to alter their differential EMG output. Like operant conditioning of the head-waving response, this operant modification of LCM activity was rapidly acquired and was specific to the contingencies of reinforcement. These results show that a restricted group of muscles, the LCMs, exhibit the essential features of the head-waving system observed at the behavioral level: (1) their activity is significantly correlated with head-waving behavior, and (2) the LCMs are capable of operant modification of their output. Thus, this restricted response system provides a useful preparation for examining the neural mechanisms of operant conditioning of head-waving in Aplysia. PMID:2795155

  19. Complete DNA sequence of the mitochondrial genome of the sea-slug, Aplysia californica: conservation of the gene order in Euthyneura.

    Science.gov (United States)

    Knudsen, Bjarne; Kohn, Andrea B; Nahir, Ben; McFadden, Catherine S; Moroz, Leonid L

    2006-02-01

    We have sequenced and characterized the complete mitochondrial genome of the sea slug, Aplysia californica, an important model organism in experimental biology and a representative of Anaspidea (Opisthobranchia, Gastropoda). The mitochondrial genome of Aplysia is in the small end of the observed sizes of animal mitochondrial genomes (14,117 bp, NCBI Accession No. NC_005827). The Aplysia genome, like most other mitochondrial genomes, encodes genes for 2 ribosomal subunit RNAs (small and large rRNAs), 22 tRNAs, and 13 protein subunits (cytochrome c oxidase subunits 1-3, cytochrome b apoenzyme, ATP synthase subunits 6 and 8, and NADH dehydrogenase subunits 1-6 and 4L). The gene order is virtually identical between opisthobranchs and pulmonates, with the majority of differences arising from tRNA translocations. In contrast, the gene order from representatives of basal gastropods and other molluscan classes is significantly different from opisthobranchs and pulmonates. The Aplysia genome was compared to all other published molluscan mitochondrial genomes and phylogenetic analyses were carried out using a concatenated protein alignment. Phylogenetic analyses using maximum likelihood based analyses of the well aligned regions of the protein sequences support both monophyly of Euthyneura (a group including both the pulmonates and opisthobranchs) and Opisthobranchia (as a more derived group). The Aplysia mitochondrial genome sequenced here will serve as an important platform in both comparative and neurobiological studies using this model organism. PMID:16230032

  20. Correlation of 125I-LSD autoradiographic labeling with serotonin voltage clamp responses in Aplysia neurons

    Energy Technology Data Exchange (ETDEWEB)

    Evans, M.L.; Kadan, M.J.; Hartig, P.R.; Carpenter, D.O. (New York State Department of Health, State University of New York, Albany (USA))

    1991-05-01

    Autoradiographic receptor binding studies using 125I-LSD (2-(125I)lysergic acid diethyamide) revealed intense labelling on the soma of a symmetrically located pair of cells in the abdominal ganglion of Aplysia californica. This binding was blocked by micromolar concentrations of serotonin and lower concentrations of the serotonergic antagonists, cyproheptadine and mianserin. Electrophysiological investigation of responses to serotonin of neurons in the left upper quadrant, where one of the labeled neurons is located, revealed a range of serotonin responses. Cells L3 and L6 have a K+ conductance increase in response to serotonin that is not blocked by cyproheptadine or mianserin. Cells L2 and L4 have a biphasic response to serotonin: a Na+ conductance increase, which can be blocked by cyproheptadine and mianserin, followed by a voltage dependent Ca2+ conductance which is blocked by Co2+ but not the serotonergic antagonists. Cell L1, and its symmetrical pair, R1, have in addition to the Na+ and Ca2+ responses observed in L2 and L4, a Cl- conductance increase blocked by LSD, cyproheptadine and mianserin. LSD had little effect on the other responses. The authors conclude that the symmetrically located cells L1 and R1 have a Cl- channel linked to a cyproheptadine- and mianserin-sensitive serotonin receptor that is selectively labelled by 125I-LSD. This receptor has many properties in common with the mammalian serotonin 1C receptor.

  1. A Single Aplysia Neurotrophin Mediates Synaptic Facilitation via Differentially Processed Isoforms

    Directory of Open Access Journals (Sweden)

    Stefan R. Kassabov

    2013-04-01

    Full Text Available Neurotrophins control the development and adult plasticity of the vertebrate nervous system. Failure to identify invertebrate neurotrophin orthologs, however, has precluded studies in invertebrate models, limiting our understanding of fundamental aspects of neurotrophin biology and function. We identified a neurotrophin (ApNT and Trk receptor (ApTrk in the mollusk Aplysia and found that they play a central role in learning-related synaptic plasticity. Blocking ApTrk signaling impairs long-term facilitation, whereas augmenting ApNT expression enhances it and induces the growth of new synaptic varicosities at the monosynaptic connection between sensory and motor neurons of the gill-withdrawal reflex. Unlike vertebrate neurotrophins, ApNT has multiple coding exons and exerts distinct synaptic effects through differentially processed and secreted splice isoforms. Our findings demonstrate the existence of bona fide neurotrophin signaling in invertebrates and reveal a posttranscriptional mechanism that regulates neurotrophin processing and the release of proneurotrophins and mature neurotrophins that differentially modulate synaptic plasticity.

  2. New ultrastructural aspects of the spermatozoon of Aplysia depilans (Gastropoda, Opisthobranchia).

    Science.gov (United States)

    Vita, P; Corral, L; Azevedo, C

    2001-01-01

    The spermatozoon of the sea hare Aplysia depilans was studied under scanning (SEM) and transmission electron microscopy (TEM). Previous descriptions of this sperm and related species, both from light and electron microscopy, were inconsistent with each other. These descriptions include A. depilans, A. punctata, A. fasciata, A. kurodai and Bursatella leachiplei. Several detailed micrographs provide a new ultrastructural model and reveal new aspects such as the presence of acrosome and the absence of a glycogen piece, therefore the modified dense ring is the terminal structure. Results also show that previous models are incorrect in many aspects. The spermatozoon is a long slender uniflagellated cell with a complex helical structure and a length of approximately 165 microm. Observed in SEM the spermatozoon has an undifferentiated head and tail. The nucleus is cord-shaped and helically intertwined with the axoneme/mitochondrial derivative complex. The mitochondrial derivative has only one glycogen helix. Glycogen presence was demonstrated by Thiéry's method. Typical heterobranchia spermatozoa features are recognised. From bibliographic analysis, a high degree of similarity was found with the sperm of Pleurobranchea maculata (Notaspidea). PMID:11686398

  3. Cytochemical localisation of lysosomal enzymes and acidic mucopolysaccharides in the salivary glands of Aplysia depilans (Opisthobranchia).

    Science.gov (United States)

    Lobo-da-Cunha, A

    2002-04-01

    Three types of secretory cells were reported in the salivary glands of Aplysia depilans: granular cells, vacuolated cells and mucocytes. To improve the characterisation of these cells, cytochemical methods for the detection of lysosomal enzymes and acidic mucopolysaccharides were applied. In granular cells, acid phosphatase and arylsulphatase were present in small lysosomes and in some secretory granules. The secretory granules could have received these enzymes after fusion with the small lysosomes that were frequently found very close to them. These cells were not stained with colloidal iron because they do not contain acidic mucopolysaccharides. In vacuolated cells, acid phosphatase and arylsulphatase were detected in lysosomes but not in the secretory vacuoles. Colloidal iron staining revealed the presence of acidic mucopolysaccharides in the vacuoles and in the Golgi apparatus of these cells. In mucocytes, lysosomes were very rare, but the secretion of these cells was very rich in acidic mucopolysaccharides. The filamentous network within the secretory vesicles was completely covered with iron particles, but practically no particles were observed over the granular masses attached to the membrane of the vesicles. Iron particles were also found in the trans-face cisternae of the U-shaped Golgi stacks, but were not seen in the cis-face cisternae or in the rough endoplasmic reticulum. PMID:12117284

  4. Light and electron microscopy studies of the oesophagus and crop epithelium in Aplysia depilans (Mollusca, Opisthobranchia).

    Science.gov (United States)

    Lobo-da-Cunha, Alexandre; Batista-Pinto, Carla

    2005-12-01

    The oesophagus and crop epithelium of Aplysia depilans consist in a single layer of columnar cells with apical microvilli, and some of them also possess cilia. Cell membrane invaginations, small vesicles, multivesicular bodies and many dense lysosomes were observed in the apical region of the cytoplasm. In most cells, a very large lipid droplet was observed above the nucleus and a smaller one was frequently found below the nucleus; glycogen granules are also present. Considering these ultrastructural features, it seems that these cells collect nutritive substances from the lumen by endocytosis, digest them in the apical lysosomes and store the resulting products. The cell bodies of mucus secreting flask-shaped cells are subepithelial in the oesophagus and intraepithelial in the crop. Histochemistry methods showed that the secretion stored in these cells contains acidic polysaccharides. Secretory vesicles with thin electron-dense filaments scattered in an electron-lucent background fill most of these cells, and the basal nucleus is surrounded by dilated rough endoplasmic reticulum cisternae containing small tubular structures. Considering the relatively low number of secretory cells, mucus production cannot be high. Moreover, since protein secreting cells were not observed in either oesophagus or crop, extracellular digestion in the lumen of these anterior segments of the digestive tract most probably depend on the enzymes secreted by the salivary and digestive glands. PMID:16260017

  5. Stomach of Aplysia depilans (Mollusca, Opisthobranchia): a histochemical, ultrastructural, and cytochemical study.

    Science.gov (United States)

    Lobo-da-Cunha, Alexandre; Batista-Pinto, Carla

    2003-06-01

    We report the results of a morphological, histochemical, and cytochemical characterization of the Aplysia depilans stomach, an organ little studied in opisthobranchs. Very thin ciliated cells with microvilli on their apical surfaces are predominant in the epithelium lining the lumen of the stomach. Many lysosomes with a strong arylsulphatase activity were present in the apical regions of these cells that could also contain some lipid droplets and glycogen. Small peroxisomes were observed, usually around lipid droplets or mitochondria. Bottle-shaped secretory cells are very common in this epithelium and produce a secretion rich in proteins and acidic mucopolysaccharides. Most of the cytoplasm of these mucus-producing cells was filled with a very high number of granules and the nucleus is dislocated to the basal region. Cisternae of rough endoplasmic reticulum were abundant around the nucleus and several Golgi stacks were also present in this area. In spite of the variation in the electron density of the granules, only one type of secretory cell seems to be present in the stomach epithelium, since granules with very different electron densities were frequently found in the same cell. A few neurons were also found in the stomach epithelium of this species. Fibrocytes, muscle cells, nerves, and amebocytes were observed in the connective tissue of the stomach wall. PMID:12655617

  6. The digestive cells of the hepatopancreas in Aplysia depilans (Mollusca, Opisthobranchia): ultrastructural and cytochemical study.

    Science.gov (United States)

    Lobo-da-Cunha, A

    2000-02-01

    Digestive cells are the most abundant cell type in the digestive diverticula of Aplysia depilans. These are tall columnar or club shaped cells, covered with microvilli on their apical surface. A large number of endocytic vesicles containing electron-dense substances can be found in the apical zone, but the presence of many heterolysosomes of large diameter is the main feature of these cells. Glycogen particles and some lipid droplets were also observed. Peroxisomes with a circular or oval profile were common, but crystalline nucleoids were not detected in them, although a dense spot in the matrix was observed in a few cases. These organelles were strongly stained after cytochemical detection of catalase activity. The Golgi stacks are formed by 4 or 5 cisternae, with dilated zones containing electron dense material. Arylsulphatase activity was detected in the Golgi stacks and also in lysosomes. Cells almost entirely occupied by a very large vacuole containing a residual dense mass seem to be digestive cells in advanced stages of maturation. The observation of semithin and ultrathin sections indicates that these very large vacuoles are the result of a fusion among the smaller lysosomes. Some images suggest that the content of these large vacuoles is extruded into the lumen of the digestive diverticula. PMID:10798317

  7. MicroRNA-22 Gates Long-Term Heterosynaptic Plasticity in Aplysia through Presynaptic Regulation of CPEB and Downstream Targets

    OpenAIRE

    Ferdinando Fiumara; Priyamvada Rajasethupathy; Igor Antonov; Stylianos Kosmidis; Sossin, Wayne S.; Kandel, Eric R.

    2015-01-01

    The maintenance phase of memory-related long-term facilitation (LTF) of synapses between sensory and motor neurons of the gill-withdrawal reflex of Aplysia depends on a serotonin (5-HT)-triggered presynaptic upregulation of CPEB, a functional prion that regulates local protein synthesis at the synapse. The mechanisms whereby serotonin regulates CPEB levels in presynaptic sensory neurons are not known. Here, we describe a sensory neuron-specific microRNA 22 (miR-22) that has multiple binding s...

  8. The Tail-Elicited Tail Withdrawal Reflex of "Aplysia" Is Mediated Centrally at Tail Sensory-Motor Synapses and Exhibits Sensitization across Multiple Temporal Domains

    Science.gov (United States)

    Philips, Gary T.; Sherff, Carolyn M.; Menges, Steven A.; Carew, Thomas J.

    2011-01-01

    The defensive withdrawal reflexes of "Aplysia californica" have provided powerful behavioral systems for studying the cellular and molecular basis of memory formation. Among these reflexes the (T-TWR) has been especially useful. In vitro studies examining the monosynaptic circuit for the T-TWR, the tail sensory-motor (SN-MN) synapses, have…

  9. Implication of dopaminergic modulation in operant reward learning and the induction of compulsive-like feeding behavior in Aplysia.

    Science.gov (United States)

    Bédécarrats, Alexis; Cornet, Charles; Simmers, John; Nargeot, Romuald

    2013-06-01

    Feeding in Aplysia provides an amenable model system for analyzing the neuronal substrates of motivated behavior and its adaptability by associative reward learning and neuromodulation. Among such learning processes, appetitive operant conditioning that leads to a compulsive-like expression of feeding actions is known to be associated with changes in the membrane properties and electrical coupling of essential action-initiating B63 neurons in the buccal central pattern generator (CPG). Moreover, the food-reward signal for this learning is conveyed in the esophageal nerve (En), an input nerve rich in dopamine-containing fibers. Here, to investigate whether dopamine (DA) is involved in this learning-induced plasticity, we used an in vitro analog of operant conditioning in which electrical stimulation of En substituted the contingent reinforcement of biting movements in vivo. Our data indicate that contingent En stimulation does, indeed, replicate the operant learning-induced changes in CPG output and the underlying membrane and synaptic properties of B63. Significantly, moreover, this network and cellular plasticity was blocked when the input nerve was stimulated in the presence of the DA receptor antagonist cis-flupenthixol. These results therefore suggest that En-derived dopaminergic modulation of CPG circuitry contributes to the operant reward-dependent emergence of a compulsive-like expression of Aplysia's feeding behavior. PMID:23685764

  10. Age-related deficits in synaptic plasticity rescued by activating PKA or PKC in sensory neurons of Aplysia californica

    Directory of Open Access Journals (Sweden)

    Andrew T Kempsell

    2015-09-01

    Full Text Available Brain aging is associated with declines in synaptic function that contribute to memory loss, including reduced postsynaptic response to neurotransmitters and decreased neuronal excitability. To understand how aging affects memory in a simple neural circuit, we studied neuronal proxies of memory for sensitization in mature versus advanced age Aplysia. Glutamate- (L-Glu- evoked excitatory currents were facilitated by the neuromodulator serotonin (5-HT in sensory neurons (SN isolated from mature but not aged animals. Activation of PKA and PKC signaling rescued facilitation of L-Glu currents in aged SN. Similarly, PKA and PKC activators restored increased excitability in aged tail SN. These results suggest that altered synaptic plasticity during aging involves defects in second messenger systems

  11. Regeneration of Aplysia Bag Cell Neurons is Synergistically Enhanced by Substrate-Bound Hemolymph Proteins and Laminin

    Science.gov (United States)

    Hyland, Callen; Dufrense, Eric R.; Forscher, Paul

    2014-04-01

    We have investigated Aplysia hemolymph as a source of endogenous factors to promote regeneration of bag cell neurons. We describe a novel synergistic effect between substrate-bound hemolymph proteins and laminin. This combination increased outgrowth and branching relative to either laminin or hemolymph alone. Notably, the addition of hemolymph to laminin substrates accelerated growth cone migration rate over ten-fold. Our results indicate that the active factor is either a high molecular weight protein or protein complex and is not the respiratory protein hemocyanin. Substrate-bound factor(s) from central nervous system-conditioned media also had a synergistic effect with laminin, suggesting a possible cooperation between humoral proteins and nervous system extracellular matrix. Further molecular characterization of active factors and their cellular targets is warranted on account of the magnitude of the effects reported here and their potential relevance for nervous system repair.

  12. Evaluation of cellular mechanisms for modulation of calcium transients using a mathematical model of fura-2 Ca2+ imaging in Aplysia sensory neurons.

    Science.gov (United States)

    Blumenfeld, H; Zablow, L; Sabatini, B

    1992-10-01

    A theoretical model of [Ca++]i diffusion, buffering, and extrusion was developed for Aplysia sensory neurons, and integrated with the measured optical transfer function of our fura-2 microscopic recording system, in order to fully simulate fura-2 video or photomultiplier tube measurements of [Ca++]i. This allowed an analysis of the spatial and temporal distortions introduced during each step of fura-2 measurements of [Ca++]i in cells. In addition, the model was used to evaluate the plausibility of several possible mechanisms for modulating [Ca++]i transients evoked by action potentials. The results of the model support prior experimental work (Blumenfeld, Spira, Kandel, and Siegelbaum, 1990. Neuron. 5: 487-499), suggesting that 5-HT and FMRFamide modulate action potential-induced [Ca++]i transients in Aplysia sensory neurons through changes in Ca++ influx, and not through changes in [Ca++]i homeostasis or release from internal stores. PMID:1420931

  13. Long-Term Habituation of the Gill-Withdrawal Reflex in Aplysia Requires Gene Transcription, Calcineurin and L-Type Voltage-Gated Calcium Channels

    OpenAIRE

    Esdin, Joseph; Pearce, Kaycey; David L Glanzman

    2010-01-01

    Although habituation is possibly the simplest form of learning, we still do not fully understand the neurobiological basis of habituation in any organism. To advance the goal of a comprehensive understanding of habituation, we have studied long-term habituation (LTH) of the gill-withdrawal reflex (GWR) in the marine snail Aplysia californica. Previously, we showed that habituation of the GWR in a reduced preparation lasts for up to 12 h, and depends on protein synthesis, as well as activation...

  14. Monosynaptic connections made by the sensory neurons of the gill- and siphon-withdrawal reflex in Aplysia participate in the storage of long-term memory for sensitization

    OpenAIRE

    Frost, William N.; Castellucci, Vincent F.; Hawkins, Robert D.; Kandel, Eric R.

    1985-01-01

    We have found that in the gill- and siphon- withdrawal reflex of Aplysia, the memory for short-term sensitization grades smoothly into long-term memory with increased amounts of sensitization training. One cellular locus for the storage of the memory underlying short-term sensitization is the set of monosynaptic connections between the siphon sensory cells and the gill and siphon motor neurons. We have now also found that these same monosynaptic connections participate in the storage of the m...

  15. Facilitatory transmitters and cAMP can modulate accommodation as well as transmitter release in Aplysia sensory neurons: Evidence for parallel processing in a single cell

    OpenAIRE

    Klein, Marc; Hochner, Binyamin; Kandel, Eric R.

    1986-01-01

    Presynaptic facilitation of transmission from sensory to motor neurons contributes significantly to behavioral sensitization of defensive withdrawal reflexes in Aplysia. Presynaptic facilitation is associated with a decrease in the serotonin-sensitive K+ conductance. This decrease broadens the presynaptic action potential. In addition, the procedures that cause facilitation—stimulation of the connective (the pathway from the tail and head), application of modulatory transmitters, or injection...

  16. Dscam Mediates Trans-Synaptic Interactions for Remodeling of Glutamate Receptors in Aplysia During De Novo and Learning-Related Synapse Formation

    OpenAIRE

    Li, Hsiu-Ling; Huang, Ben S.; Vishwasrao, Harshad; Sutedja, Nadia; Chen, Wei; Jin, Iksung; Hawkins, Robert D.; Bailey, Craig H.; Kandel, Eric R.

    2009-01-01

    Trans-synaptic interactions between neurons are essential during both developmental and learning-related synaptic growth. We have used Aplysia neuronal cultures to examine the contribution of trans-synaptic signals in both types of synapse formation. We find that during de novo synaptogenesis, specific presynaptic innervation is required for the clustering of postsynaptic AMPA-like but not NMDA-like receptors. We further find that the cell adhesion molecule Dscam is involved in these trans-sy...

  17. Action-potential duration and the modulation of transmitter release from the sensory neurons of Aplysia in presynaptic facilitation and behavioral sensitization

    OpenAIRE

    Hochner, Binyamin; Klein, Marc; Schacher, Samuel; Kandel, Eric R.

    1986-01-01

    Presynaptic facilitation of transmitter release from Aplysia sensory neurons is an important contributor to behavioral sensitization of the gill and siphon withdrawal reflex. The enhanced release is accompanied by reduction of the serotonin-sensitive S current in the sensory neurons and a consequent increase in duration of the presynaptic action potential (ranging from 10% to 30%). We find that changes of similar magnitude in the duration of depolarizing voltage-clamp steps in sensory neurons...

  18. Identifying Discriminating Features of Motor Patterns for Different Behaviors: Distinguishing Biting, Swallowing and Rejection in Aplysia californica from in vivo recordings

    OpenAIRE

    Miranda J Cullins

    2012-01-01

    Changes in timing and duration of muscle activation create multiple behaviors. In cats, forward versus backward walking is due to changing motor unit activation order (Buford and Smith 1990). Sensory feedback shapes the length of the stance phase during locomotion in cats (Hiebert et al. 1996). Motor patterns for turtle hind limb during swimming and scratching have both shared and distinct elements (Stein 2005). Aplysia californica, which generates different feeding behaviors using the sa...

  19. Stages in axon formation: observations of growth of Aplysia axons in culture using video-enhanced contrast-differential interference contrast microscopy

    OpenAIRE

    1986-01-01

    The regenerative growth in culture of the axons of two giant identified neurons from the central nervous system of Aplysia californica was observed using video-enhanced contrast-differential interference contrast microscopy. This technique allowed the visualization in living cells of the membranous organelles of the growth cone. Elongation of axonal branches always occurred through the same sequence of events: A flat organelle-free veil protruded from the front of the growth cone, gradually f...

  20. Cloning of the non-neuronal intermediate filament protein of the gastropod Aplysia californica; identification of an amino acid residue essential for the IFA epitope.

    Science.gov (United States)

    Riemer, D; Dodemont, H; Weber, K

    1991-12-01

    We describe the isolation and characterization of a full-length cDNA corresponding to the larger non-neuronal (nn) intermediate filament (IF) protein of the gastropod Aplysia californica. Comparison of the sequences of the nn-IF proteins from Aplysia californica and Helix aspersa shows a strong evolutionary drift. At a 72% sequence identity level, the IF proteins of Opisthobranchia and Pulmonata show a larger distance than vimentins from Xenopus and mammals. The sequence comparison of the two snail proteins provides an important step in understanding the epitope of the monoclonal antibody IFA mapped by previous studies to the consensus sequence at the carboxy-terminal end of the rod domain of IF proteins. We identify for the first time in a naturally occurring IF protein a single amino acid exchange which leads to the loss of the epitope. The consensus sequence YRKLLEGEE present in IFA-positive proteins such as the Helix IF protein is changed in the IFA-negative Aplysia protein only by the conservative substitution of the arginine (R) by a lysine (K). Thus, the IFA epitope is not a necessity of IF structure, and its presence or absence on different IF proteins reflects only small changes in an otherwise conserved consensus sequence. Consequently, lack of IFA reactivity does not exclude the presence of IF. This result predicts that IF are much more universally expressed in lower eukaryotes than currently expected from immunological results with the monoclonal antibody IFA. PMID:1724961

  1. Change in excitability of a putative decision-making neuron in Aplysia serves as a mechanism in the decision not feed following food satiation

    Science.gov (United States)

    Dickinson, Kathy J.; Wainwright, Marcy L.; Mozzachiodi, Riccardo

    2014-01-01

    Although decision making is a ubiquitous function, the understanding of its underlying mechanisms remains limited, particularly at the single-cell level. In this study, we used the decision not to feed that follows satiation in the marine mollusk Aplysia to examine the role of putative decision-making neuron B51 in this process. B51 is a neuron in the feeding neural circuit that exhibits decision-making characteristics in vitro, which bias the circuit toward producing the motor programs responsible for biting behavior. Once satiated, Aplysia decided not to bite for a prolonged period of time (≥ 24 h) when presented with a food stimulus that normally elicits feeding in non-satiated animals. Twenty-four hours after satiation, suppressed feeding was accompanied by a significant decrease of B51 excitability compared to the control group of unfed animals. No differences were measured in B51 resting membrane properties or synaptic input to B51 between the satiated and control groups. When B51 properties were measured at a time point in which feeding had recovered from the suppressive effects of satiation (i.e., 96 h after satiation), no difference in B51 excitability was observed between satiated and control groups. These findings indicate that B51 excitability changes in a manner that is coherent with the modifications in biting resulting from food satiation, thus implicating this neuron as a site of plasticity underlying the decision not to bite following food satiation in Aplysia. PMID:25527117

  2. MicroRNA-22 Gates Long-Term Heterosynaptic Plasticity in Aplysia through Presynaptic Regulation of CPEB and Downstream Targets.

    Science.gov (United States)

    Fiumara, Ferdinando; Rajasethupathy, Priyamvada; Antonov, Igor; Kosmidis, Stylianos; Sossin, Wayne S; Kandel, Eric R

    2015-06-30

    The maintenance phase of memory-related long-term facilitation (LTF) of synapses between sensory and motor neurons of the gill-withdrawal reflex of Aplysia depends on a serotonin (5-HT)-triggered presynaptic upregulation of CPEB, a functional prion that regulates local protein synthesis at the synapse. The mechanisms whereby serotonin regulates CPEB levels in presynaptic sensory neurons are not known. Here, we describe a sensory neuron-specific microRNA 22 (miR-22) that has multiple binding sites on the mRNA of CPEB and inhibits it in the basal state. Serotonin triggers MAPK/Erk-dependent downregulation of miR-22, thereby upregulating the expression of CPEB, which in turn regulates, through functional CPE elements, the presynaptic expression of atypical PKC (aPKC), another candidate regulator of memory maintenance. Our findings support a model in which the neurotransmitter-triggered downregulation of miR-22 coordinates the regulation of genes contributing synergistically to the long-term maintenance of memory-related synaptic plasticity. PMID:26095361

  3. MicroRNA-22 Gates Long-Term Heterosynaptic Plasticity in Aplysia through Presynaptic Regulation of CPEB and Downstream Targets

    Directory of Open Access Journals (Sweden)

    Ferdinando Fiumara

    2015-06-01

    Full Text Available The maintenance phase of memory-related long-term facilitation (LTF of synapses between sensory and motor neurons of the gill-withdrawal reflex of Aplysia depends on a serotonin (5-HT-triggered presynaptic upregulation of CPEB, a functional prion that regulates local protein synthesis at the synapse. The mechanisms whereby serotonin regulates CPEB levels in presynaptic sensory neurons are not known. Here, we describe a sensory neuron-specific microRNA 22 (miR-22 that has multiple binding sites on the mRNA of CPEB and inhibits it in the basal state. Serotonin triggers MAPK/Erk-dependent downregulation of miR-22, thereby upregulating the expression of CPEB, which in turn regulates, through functional CPE elements, the presynaptic expression of atypical PKC (aPKC, another candidate regulator of memory maintenance. Our findings support a model in which the neurotransmitter-triggered downregulation of miR-22 coordinates the regulation of genes contributing synergistically to the long-term maintenance of memory-related synaptic plasticity.

  4. Taste-mediated behavioral and electrophysiological responses by the predatory fish Ariopsis felis to deterrent pigments from Aplysia californica ink.

    Science.gov (United States)

    Nusnbaum, Matthew; Aggio, Juan F; Derby, Charles D

    2012-04-01

    Chemical defenses are used by many organisms to avoid predation, and these defenses may function by stimulating predators' chemosensory systems. Our study examined detection mechanisms for components of defensive ink of sea hares, Aplysia californica, by predatory sea catfish, Ariopsis felis. Behavioral analyses show aplysioviolin and phycoerythrobilin are detected intra-orally and by barbels and are deterrent at concentrations as low as 0.1% full strength. We performed electrophysiological recordings from the facial-trigeminal nerve complex innervating the maxillary barbel and tested aplysioviolin, phycoerythrobilin, amino acids, and bile salts in cross-adaptation experiments. Amino acids and bile salts are known stimulatory compounds for teleost taste systems. Our results show aplysioviolin and phycoerythrobilin are equally stimulatory and completely cross-adapt to each other's responses. Adaptation to aplysioviolin or phycoerythrobilin reduced but did not eliminate responses to amino acids or bile salts. Adaptation to amino acids or bile salts incompletely reduced responses to aplysioviolin or phycoerythrobilin. The fact that cross-adaptations with aplysioviolin and phycoerythrobilin were not completely reciprocal indicates there are amino acid and bile salt sensitive fibers insensitive to aplysioviolin and phycoerythrobilin. These results indicate two gustatory pathways for aplysioviolin and phycoerythrobilin: one independent of amino acids and bile salts and another shared with some amino acids. PMID:22200975

  5. Transforming growth factor β recruits persistent MAPK signaling to regulate long-term memory consolidation in Aplysia californica.

    Science.gov (United States)

    Shobe, Justin; Philips, Gary T; Carew, Thomas J

    2016-05-01

    In this study, we explore the mechanistic relationship between growth factor signaling and kinase activity that supports the protein synthesis-dependent phase of long-term memory (LTM) consolidation for sensitization ofAplysia Specifically, we examine LTM for tail shock-induced sensitization of the tail-elicited siphon withdrawal (T-SW) reflex, a form of memory that requires both (i) extracellular signal-regulated kinase (ERK1/2; MAPK) activity within identified sensory neurons (SNs) that mediate the T-SW and (ii) the activation of transforming growth factor β (TGFβ) signaling. We now report that repeated tail shocks that induce intermediate-term (ITM) and LTM for sensitization, also induce a sustained post-training phase of MAPK activity in SNs (lasting at least 1 h). We identified two mechanistically distinct phases of post-training MAPK: (i) an immediate phase that does not require ongoing protein synthesis or TGFβ signaling, and (ii) a sustained phase that requires both protein synthesis and extracellular TGFβ signaling. We find that LTM consolidation requires sustained MAPK, and is disrupted by inhibitors of protein synthesis and TGFβ signaling during the consolidation window. These results provide strong evidence that TGFβ signaling sustains MAPK activity as an essential mechanistic step for LTM consolidation. PMID:27084925

  6. A Single Aplysia Neurotrophin Mediates Synaptic Facilitation via Differentially Processed Isoforms Secreted as Mature or Precursor Forms

    Science.gov (United States)

    Kassabov, Stefan R.; Choi, Yun-Beom; Karl, Kevin A.; Vishwasrao, Harshad D.; Bailey, Craig H.; Kandel, Eric R.

    2014-01-01

    Summary Neurotrophins control the development and adult plasticity of the vertebrate nervous system. Failure to identify invertebrate neurotrophin orthologs, however, has precluded studies in invertebrate models, limiting understanding of fundamental aspects of neurotrophin biology and function. We identified a neurotrophin (ApNT) and Trk receptor (ApTrk) in the mollusk Aplysia and find they play a central role in learning related synaptic plasticity. ApNT increases the magnitude and lowers the threshold for induction of long-term facilitation and initiates the growth of new synaptic varicosities at the monosynaptic connection between sensory and motor neurons of the gill-withdrawal reflex. Unlike vertebrate neurotrophins, ApNT has multiple coding exons and exerts distinct synaptic effects through differentially processed and secreted splice isoforms. Our findings demonstrate the existence of bona-fide neurotrophin signaling in invertebrates and reveal a novel, post-transcriptional mechanism, regulating neurotrophin processing and the release of pro- and mature neurotrophins which differentially modulate synaptic plasticity. PMID:23562154

  7. Differential effects of ionizing radiation on the circadian oscillator and other functions in the eye of Aplysia

    International Nuclear Information System (INIS)

    Ionizing radiation has been used to selectively separate the circadian oscillator function of the eye of Aplysia from some of its other functions-synchronous compound action potential (CAP) generation, the light response, synaptic transmission between photoreceptors and output neurons, and the bursting pacemaker mechanism. Doses of 4-krad (50 kV peak) x-rays have a minimal effect on the circadian rhythm of CAP frequency, measured from the optic nerve, whereas irradiation with a 40-krad dose abolishes the rhythm without affecting any of the four other functions of this eye. We estimate a 50% survival of the oscillator function at doses of about 6 krad. The results, including those from selective irradiation of the anterior or posterior poles of the eye, suggest that there are a number of circadian oscillators in the eye-most of them in the posterior portion near the optic nerve. An approximate target size has been obtained from target theory, approx. =108 A3, which is somewhat larger than the target size for viral infectivity function, as one example. However, this approximate target size and the fact that recovery or repair can occur in vivo suggest that the oscillator may involve nucleic acid molecules

  8. Release properties of individual presynaptic boutons expressed during homosynaptic depression and heterosynaptic facilitation of the Aplysia sensorimotor synapse

    Directory of Open Access Journals (Sweden)

    Guy eMalkinson

    2013-09-01

    Full Text Available Much of what we know about the mechanisms underlying Homosynaptic Depression (HSD and heterosynaptic facilitation is based on intracellular recordings of integrated postsynaptic potentials. This methodological approach views the presynaptic apparatus as a single compartment rather than taking a more realistic representation reflecting the fact that it is made up of tens to hundreds of individual and independent Presynaptic Release Boutons (PRBs. Using cultured Aplysia sensorimotor synapses, we reexamined HSD and its dishabituation by imaging the release properties of individual PRBs. We find that the PRB population is heterogeneous and can be clustered into three groups: approximately 25% of the PRBs consistently release neurotransmitter throughout the entire habituation paradigm (35 stimuli, 0.05Hz and have a relatively high quantal content, 36% of the PRBs display intermittent failures only after the tenth stimulation, and 39% are low quantal-content PRBs that exhibit intermittent release failures from the onset of the habituation paradigm. 5HT-induced synaptic dishabituation by a single 5HT application was generated by the enhanced recovery of the quantal content of the habituated PRBs and did not involve the recruitment of new release boutons. The characterization of the PRB population as heterogeneous in terms of its temporal pattern of release-probability and quantal content provides new insights into the mechanisms underlying HSD and its dishabituation.

  9. Toxic, antimicrobial and hemagglutinating activities of the purple fluid of the sea hare Aplysia dactylomela Rang, 1828

    Directory of Open Access Journals (Sweden)

    Melo V.M.M.

    1998-01-01

    Full Text Available The antimicrobial, hemagglutinating and toxic activities of the purple fluid of the sea hare Aplysia dactylomela are described. Intact or dialyzed purple fluid inhibited the growth of species of Gram-positive and Gram-negative bacteria and the action was not bactericidal but bacteriostatic. The active factor or factors were heat labile and sensitive to extreme pH values. The fluid preferentially agglutinated rabbit erythrocytes and, to a lesser extent, human blood cells, and this activity was inhibited by the glycoprotein fetuin, a fact suggesting the presence of a lectin. The fluid was also toxic to brine shrimp nauplii (LD50 141.25 µg protein/ml and to mice injected intraperitoneally (LD50 201.8 ± 8.6 mg protein/kg, in a dose-dependent fashion. These toxic activities were abolished when the fluid was heated. Taken together, the data suggest that the activities of the purple fluid are due primarily to substance(s of a protein nature which may be involved in the chemical defense mechanism of this sea hare.

  10. Aplysia cell adhesion molecule and a novel protein kinase C activity in the postsynaptic neuron are required for presynaptic growth and initial formation of specific synapses

    OpenAIRE

    Hu, Jiang-Yuan; Chen, Yang; Bougie, Joanna K; Sossin, Wayne S.; Schacher, Samuel

    2010-01-01

    To explore the role of both Aplysia cell adhesion molecule (ApCAM) and activity of specific protein kinase C (PKC) isoforms in the initial formation of sensory neuron synapses with specific postsynaptic targets (L7 but not L11), we examined presynaptic growth, initial synapse formation, and the expression of the presynaptic neuropeptide sensorin following cell-specific reduction of ApCAM or of a novel PKC activity. Synapse formation between sensory neurons and L7 begins by 3 h after plating a...

  11. Several Days of CPEB-Dependent Local Protein Synthesis Are Required to Stabilize Synaptic Growth for Persistence of Long-Term Facilitation in Aplysia

    OpenAIRE

    Miniaci, Maria Concetta; Kim, Joung-Hun; Puthenveettil, Sathyanarayanan; Si, Kausik; Zhu, Huixiang; Kandel, Eric R.; Bailey, Craig H.

    2008-01-01

    The time course of the requirement for local protein synthesis in the stabilization of learning-related synaptic growth and the persistence of long-term memory was examined using Aplysia bifurcated sensory neuron-motor neuron cultures. We find that following repeated pulses of serotonin (5-HT) the local perfusion of emetine, an inhibitor of protein synthesis, or a TAT-AS oligonucleotide directed against ApCPEB blocks long-term facilitation (LTF) at either 24 hr or 48 hr and leads to a selecti...

  12. Repeated pulses of serotonin required for long-term facilitation activate mitogen-activated protein kinase in sensory neurons of Aplysia

    OpenAIRE

    Michael, Dan; Martin, Kelsey C.; Seger, Rony; Ning, Ming-Ming; Baston, Rene; Kandel, Eric R.

    1998-01-01

    Long-term facilitation of the connections between the sensory and motor neurons of the gill-withdrawal reflex in Aplysia requires five repeated pulses of serotonin (5-HT). The repeated pulses of 5-HT initiate a cascade of gene activation that leads ultimately to the growth of new synaptic connections. Several genes in this process have been identified, including the transcriptional regulators apCREB-1, apCREB-2, apC/EBP, and the cell adhesion molecule apCAM, which is thought to be involved in...

  13. Molecular Cloning, Expression Pattern, and Immunocytochemical Localization of a Gonadotropin-Releasing Hormone-like Molecule in the Gastropod Mollusk, Aplysia californica

    OpenAIRE

    Zhang, Lihong; Tello, Javier A; Zhang, Weimin; Tsai, Pei-San

    2007-01-01

    Successful reproduction in vertebrates depends upon the actions of gonadotropin-releasing hormone (GnRH). Despite the wide presence of GnRH in Phylum Chordata, GnRH has not been isolated in protostomes other than the common octopus. To provide information on the evolution of this critical hormone, we isolated the full-length cDNA of a GnRH-like molecule from the central nervous system of a gastropod mollusk, the sea hare Aplysia californica. The open reading frame of this cDNA encodes a prote...

  14. Myogenesis in Aplysia californica (Cooper, 1863) (Mollusca, Gastropoda, Opisthobranchia) with special focus on muscular remodeling during metamorphosis.

    Science.gov (United States)

    Wollesen, Tim; Wanninger, Andreas; Klussmann-Kolb, Annette

    2008-07-01

    To date only few comparative approaches tried to reconstruct the ontogeny of the musculature in invertebrates. This may be due to the difficulties involved in reconstructing three dimensionally arranged muscle systems by means of classical histological techniques combined with light or transmission electron microscopy. Within the scope of the present study we investigated the myogenesis of premetamorphic, metamorphic, and juvenile developmental stages of the anaspidean opisthobranch Aplysia californica using fluorescence F-actin-labeling in conjunction with modern confocal laser scanning microscopy. We categorized muscles with respect to their differentiation and degeneration and found three true larval muscles that differentiate during the embryonic and veliger phase and degenerate during or slightly after metamorphosis. These are the larval retractor, the accessory larval retractor, and the metapodial retractor muscle. While the pedal retractor muscle, some transversal mantle fibers and major portions of the cephalopedal musculature are continued and elaborated during juvenile and adult life, the buccal musculature and the anterior retractor muscle constitute juvenile/adult muscles which differentiate during or after metamorphosis. The metapodial retractor muscle has never been reported for any other gastropod taxon. Our findings indicate that the late veliger larva of A. californica shares some common traits with veligers of other gastropods, such as a larval retractor muscle. However, the postmetamorphic stages exhibit only few congruencies with other gastropod taxa investigated to date, which is probably due to common larval but different adult life styles within gastropods. Accordingly, this study provides further evidence for morphological plasticity in gastropod myogenesis and stresses the importance of ontogenetic approaches to understand adult conditions and life history patterns. PMID:18157859

  15. Ultrastructural and cytochemical aspects of the basophilic cells in the hepatopancreas ofAplysia depilans(Mollusca, Opisthobranchia).

    Science.gov (United States)

    Lobo-da-Cunha, A

    1999-02-01

    The basophilic cells ofAplysia depilanshave a pyramidal shape and a large nucleus usually located near the center or in the basal half of the cell. The nucleus possesses several clumps of condensed chromatin and a prominent nucleolus. The great profusion of rough endoplasmic reticulum cisterns in a major feature of these cells. Secretion granules are accumulated in the apical zone, and arylsulphatase was detected in some of them. In some basophilic cells a very substantial part of the cell volume was occupied by clear vacuoles, some of them reaching 9 mum. However, in other cells only a few vacuoles were observed. Probably the cells with just a few vacuoles are still young, and after a progressive accumulation, the vacuoles become abundant in old cells. The presence of a dark nucleus in the cells with a large number of vacuoles suggests that they are in a final stage of their life. Arylsulphatase was detected in the vacuoles and also in small secondary lysosomes containing substances in digestion. Bundles of tubules with 50 nm in diameter were found within some cisterns of rough endoplasmic reticulum. A cell fraction enriched in mannitol oxidase, extracted from the hepatopancreas of a terrestrial slug, consisted in very similar tubular structures. Using a histochemical method, mannitol oxidase was detected in the basophilic cells ofA. depilans, and it may be associated with the tubular structures of the endoplasmic reticulum. This is the first report of mannitol oxidase in opisthobranch molluscs. Almost spherical peroxisomes with a small nucleoid were abundant in these cells. The nucleoids presented a rectangular section, but a crystalline structure was not evident. The peroxisomes were stained after the cytochemical detection of catalase activity. PMID:18627851

  16. Activity changes in jaw motor neurons induced by egg-laying hormone contribute to the feeding suppression during egg-laying behavior in Aplysia kurodai.

    Science.gov (United States)

    Narusuye, Kenji; Hamaguchi, Aya; Nagahama, Tatsumi

    2013-01-01

    Egg-laying behavior in Aplysia is accompanied by behavioral changes such as feeding suppression. We investigated the effects of the egg-laying hormone (ELH) on food intake, the activity patterns of jaw muscles, and the activity of buccal neurons (multi-action neuron [MA1] and jaw-closing motor neuron [JC2]), which are elements of the feeding neural circuits controlling jaw movements in Aplysia kurodai. Injection of ELH into the body cavity inhibited the intake of seaweed. After ELH application, the rhythmic activity of jaw muscles that was induced by preferred taste stimulation elicited fewer ingestion-like responses and increased the number of rejection-like responses. ELH applied to the buccal ganglia increased the firing activity of JC2 during spontaneous rhythmic responses and during the rhythmic feeding-like responses that were evoked by electrical stimulation of the esophageal nerves. In the 2 types of rhythmic responses, the Dn (normalized value of the delay time of JC2 firing onset) decreased after ELH application as compared with the control. Furthermore, ELH decreased the size of MA1-induced inhibitory postsynaptic currents in JC2. These results suggest that ELH changes the buccal motor program from ingestion to rejection on the basis of our previous results, and may contribute to a decrease in food intake during egg laying. PMID:23501243

  17. How to produce a chemical defense: structural elucidation and anatomical distribution of aplysioviolin and phycoerythrobilin in the sea hare Aplysia californica.

    Science.gov (United States)

    Kamio, Michiya; Nguyen, Linh; Yaldiz, Seymanur; Derby, Charles D

    2010-05-01

    We previously used bioassay-guided fractionation to identify phycoerythrobilin (1) and its monomethyl ester, aplysioviolin (2), as components in the ink secretion of a marine gastropod, the sea hare Aplysia californica, that act as chemical deterrents against predatory blue crabs. This was the first report of 1 as a natural product. Compound 2 was previously reported as a natural product from three species of Aplysia (A. fasciata, A. dactylomela, and A. parvula), but the reported structure and composition of stereoisomers of 2 are different among these species. Sea hares are thought to produce 2 from phycoerythrin, a photosynthetic pigment in their red-algal diet composed of a phycobiliprotein covalently linked to the chromophore 1, by cleavage of the covalent bond and methylation of 1, but neither the sequence nor the anatomical location of the cleavage and methylation is known. In this study, we clarify the structure of 1 and 2 in ink secretion of A. californica, and describe the distribution of 1 and 2 in the tissues of sea hares. We conclude that cleavage of the covalent bond in phycoerythrin occurs first, forming 1 in the digestive gland, followed by methylation of 1 to yield 2 in the ink gland. PMID:20491075

  18. A novel function for serotonin-mediated short-term facilitation in Aplysia: Conversion of a transient, cell-wide homosynaptic Hebbian plasticity into a persistent, protein synthesis-independent synapse-specific enhancement

    OpenAIRE

    Bailey, Craig H.; Giustetto, Maurizio; Zhu, Hiuxiang; Chen, Mary; Kandel, Eric R.

    2000-01-01

    Studies of sensitization and classical conditioning of the gill-withdrawal reflex in Aplysia have shown that the synaptic connections between identified glutamatergic sensory neurons and motor neurons can be enhanced in one of two ways: by a heterosynaptic (modulatory input-dependent) mechanism that gives rise with repetition to long-term facilitation and by a homosynaptic (activity-dependent) mechanism that gives rise with repetition to a facilitation that is part...

  19. In vitro Charakterisierung der tumor-lytischen Wirkung des Aplysia punctata ink toxins (APIT) auf humane Tumorzellen und Etablierung eines Xenotransplantat-Modells als Basis für in vivo Analysen von APIT

    OpenAIRE

    Brink, Nicola

    2010-01-01

    In vitro characterization of Aplysia punctata ink toxin (APIT) for its anti-cancer efficacy against human cancer cell lines and establishment of xenograft models for in vivo analyzing of APIT The increasing number of patients suffering from different forms of cancer remains a major health problem in industrialized countries. Although commonly used as standard treatment options, surgery, radiation and classical chemotherapy often result in severe adverse reactions, or are even unsuccessful...

  20. Evidence for the involvement of carbonic anhydrase and urease in calcium carbonate formation in the gravity-sensing organ of Aplysia californica

    Science.gov (United States)

    Pedrozo, H. A.; Schwartz, Z.; Dean, D. D.; Harrison, J. L.; Campbell, J. W.; Wiederhold, M. L.; Boyan, B. D.

    1997-01-01

    To better understand the mechanisms that could modulate the formation of otoconia, calcium carbonate granules in the inner ear of vertebrate species, we examined statoconia formation in the gravity-sensing organ, the statocyst, of the gastropod mollusk Aplysia californica using an in vitro organ culture model. We determined the type of calcium carbonate present in the statoconia and investigated the role of carbonic anhydrase (CA) and urease in regulating statocyst pH as well as the role of protein synthesis and urease in statoconia production and homeostasis in vitro. The type of mineral present in statoconia was found to be aragonitic calcium carbonate. When the CA inhibitor, acetazolamide (AZ), was added to cultures of statocysts, the pH initially (30 min) increased and then decreased. The urease inhibitor, acetohydroxamic acid (AHA), decreased statocyst pH. Simultaneous addition of AZ and AHA caused a decrease in pH. Inhibition of urease activity also reduced total statoconia number, but had no effect on statoconia volume. Inhibition of protein synthesis reduced statoconia production and increased statoconia volume. In a previous study, inhibition of CA was shown to decrease statoconia production. Taken together, these data show that urease and CA play a role in regulating statocyst pH and the formation and maintenance of statoconia. CA produces carbonate ion for calcium carbonate formation and urease neutralizes the acid formed due to CA action, by production of ammonia.

  1. Comprehensive enzymatic analysis of the amylolytic system in the digestive fluid of the sea hare, Aplysia kurodai: Unique properties of two α-amylases and two α-glucosidases

    OpenAIRE

    Akihiko Tsuji; Nami Nishiyama; Miki Ohshima; Saori Maniwa; Shuji Kuwamura; Masataka Shiraishi; Keizo Yuasa

    2014-01-01

    Sea lettuce (Ulva pertusa) is a nuisance species of green algae that is found all over the world. East-Asian species of the marine gastropod, the sea hare Aplysia kurodai, shows a clear feeding preference for sea lettuce. Compared with cellulose, sea lettuce contains a higher amount of starch as a storage polysaccharide. However, the entire amylolytic system in the digestive fluid of A. kurodai has not been studied in detail. We purified α-amylases and α-glucosidases from the digestive fluid ...

  2. Evaluation of the cholinomimetic actions of trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana (Gastropoda, Opisthobranchia).

    Science.gov (United States)

    Kerchove, C M; Markus, R P; Freitas, J C; Costa-Lotufo, L V

    2002-04-01

    Trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana, negatively modulates vagal response, indicating a probable ability to inhibit cholinergic responses. In the present study, the pharmacological profile of trimethylsulfonium was characterized on muscarinic and nicotinic acetylcholine receptors. In rat jejunum the contractile response induced by trimethylsulfonium (pD2 = 2.46 +/- 0.12 and maximal response = 2.14 +/- 0.32 g) was not antagonized competitively by atropine. The maximal response (Emax) to trimethylsulfonium was diminished in the presence of increasing doses of atropine (P<0.05), suggesting that trimethylsulfonium-induced contraction was not related to muscarinic stimulation, but might be caused by acetylcholine release due to presynaptic stimulation. Trimethylsulfonium displaced [3H]-quinuclidinyl benzilate from rat cortex membranes with a low affinity (Ki = 0.5 mM). Furthermore, it caused contraction of frog rectus abdominis muscles (pD2 = 2.70 +/- 0.06 and Emax = 4.16 +/- 0.9 g), which was competitively antagonized by d-tubocurarine (1, 3 or 10 microM) with a pA2 of 5.79, suggesting a positive interaction with nicotinic receptors. In fact, trimethylsulfonium displaced [3H]-nicotine from rat diaphragm muscle membranes with a Ki of 27.1 microM. These results suggest that trimethylsulfonium acts as an agonist on nicotinic receptors, and thus contracts frog skeletal rectus abdominis muscle and rat jejunum smooth muscle via stimulation of postjunctional and neuronal prejunctional nicotinic cholinoreceptors, respectively. PMID:11960200

  3. Evaluation of the cholinomimetic actions of trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana (Gastropoda, Opisthobranchia

    Directory of Open Access Journals (Sweden)

    C.M. Kerchove

    2002-04-01

    Full Text Available Trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana, negatively modulates vagal response, indicating a probable ability to inhibit cholinergic responses. In the present study, the pharmacological profile of trimethylsulfonium was characterized on muscarinic and nicotinic acetylcholine receptors. In rat jejunum the contractile response induced by trimethylsulfonium (pD2 = 2.46 ± 0.12 and maximal response = 2.14 ± 0.32 g was not antagonized competitively by atropine. The maximal response (Emax to trimethylsulfonium was diminished in the presence of increasing doses of atropine (P<0.05, suggesting that trimethylsulfonium-induced contraction was not related to muscarinic stimulation, but might be caused by acetylcholine release due to presynaptic stimulation. Trimethylsulfonium displaced [³H]-quinuclidinyl benzilate from rat cortex membranes with a low affinity (Ki = 0.5 mM. Furthermore, it caused contraction of frog rectus abdominis muscles (pD2 = 2.70 ± 0.06 and Emax = 4.16 ± 0.9 g, which was competitively antagonized by d-tubocurarine (1, 3 or 10 µM with a pA2 of 5.79, suggesting a positive interaction with nicotinic receptors. In fact, trimethylsulfonium displaced [³H]-nicotine from rat diaphragm muscle membranes with a Ki of 27.1 µM. These results suggest that trimethylsulfonium acts as an agonist on nicotinic receptors, and thus contracts frog skeletal rectus abdominis muscle and rat jejunum smooth muscle via stimulation of postjunctional and neuronal prejunctional nicotinic cholinoreceptors, respectively.

  4. Comprehensive enzymatic analysis of the amylolytic system in the digestive fluid of the sea hare, Aplysia kurodai: Unique properties of two α-amylases and two α-glucosidases

    Directory of Open Access Journals (Sweden)

    Akihiko Tsuji

    2014-01-01

    Full Text Available Sea lettuce (Ulva pertusa is a nuisance species of green algae that is found all over the world. East-Asian species of the marine gastropod, the sea hare Aplysia kurodai, shows a clear feeding preference for sea lettuce. Compared with cellulose, sea lettuce contains a higher amount of starch as a storage polysaccharide. However, the entire amylolytic system in the digestive fluid of A. kurodai has not been studied in detail. We purified α-amylases and α-glucosidases from the digestive fluid of A. kurodai and investigated the synergistic action of these enzymes on sea lettuce. A. kurodai contain two α-amylases (59 and 80 kDa and two α-glucosidases (74 and 86 kDa. The 59-kDa α-amylase, but not the 80-kDa α-amylase, was markedly activated by Ca2+ or Cl−. Both α-amylases degraded starch and maltoheptaose, producing maltotriose, maltose, and glucose. Glucose production from starch was higher with 80-kDa α-amylase than with 59-kDa α-amylase. Kinetic analysis indicated that 74-kDa α-glucosidase prefers short α-1,4-linked oligosaccharide, whereas 86-kDa α-glucosidase prefers large α-1,6 and α-1,4-linked polysaccharides such as glycogen. When sea lettuce was used as a substrate, a 2-fold greater amount of glucose was released by treatment with 59-kDa α-amylase and 74-kDa α-glucosidase than by treatment with 45-kDa cellulase and 210-kDa β-glucosidase of A. kurodai. Unlike mammals, sea hares efficiently digest sea lettuce to glucose by a combination of two α-amylases and two α-glucosidases in the digestive fluids without membrane-bound maltase–glucoamylase and sucrase–isomaltase complexes.

  5. Mechanisms of action of escapin, a bactericidal agent in the ink secretion of the sea hare Aplysia californica: rapid and long-lasting DNA condensation and involvement of the OxyR-regulated oxidative stress pathway.

    Science.gov (United States)

    Ko, Ko-Chun; Tai, Phang C; Derby, Charles D

    2012-04-01

    The marine snail Aplysia californica produces escapin, an L-amino acid oxidase, in its defensive ink. Escapin uses L-lysine to produce diverse products called escapin intermediate products of L-lysine (EIP-K), including α-amino-ε-caproic acid, Δ¹-piperidine-2-carboxylic acid, and Δ²-piperidine-2-carboxylic acid. EIP-K and H₂O₂ together, but neither alone, is a powerful bactericide. Here, we report bactericidal mechanisms of escapin products on Escherichia coli. We show that EIP-K and H₂O₂ together cause rapid and long-lasting DNA condensation: 2-min treatment causes significant DNA condensation and killing, and 10-min treatment causes maximal effect, lasting at least 70 h. We isolated two mutants resistant to EIP-K plus H₂O₂, both having a single missense mutation in the oxidation regulatory gene, oxyR. A complementation assay showed that the mutated gene, oxyR(A233V), renders resistance to EIP-K plus H₂O₂, and a gene dosage effect leads to reduction of resistance for strains carrying wild-type oxyR. Temperature stress with EIP-K does not produce the bactericidal effect, suggesting the effect is due to a specific response to oxidative stress. The null mutant for any single DNA-binding protein--Dps, H-NS, Hup, Him, or MukB--was not resistant to EIP-K plus H₂O₂, suggesting that no single DNA-binding protein is necessary to mediate this bactericidal effect, but allowing for the possibility that EIP-K plus H₂O₂ could function through a combination of DNA-binding proteins. The bactericidal effect of EIP-K plus H₂O₂ was eliminated by the ferrous ion chelator 1,10-phenanthroline, and it was reduced by the hydroxyl radical scavenger thiourea, suggesting hydroxyl radicals mediate the effects of EIP-K plus H₂O₂. PMID:22232273

  6. Habituation in the Tail Withdrawal Reflex Circuit is Impaired During Aging in Aplysia californica

    OpenAIRE

    Kempsell, Andrew T; Fieber, Lynne A.

    2016-01-01

    The relevance of putative contributors to age-related memory loss are poorly understood. The tail withdrawal circuit of the sea hare, a straightforward neural model, was used to investigate the aging characteristics of rudimentary learning. The simplicity of this neuronal circuit permits attribution of declines in the function of specific neurons to aging declines. Memory was impaired in advanced age animals compared to their performance at the peak of sexual maturity, with habituation traini...

  7. A Presynaptic Role for FMRP during Protein Synthesis-Dependent Long-Term Plasticity in "Aplysia"

    Science.gov (United States)

    Till, Sally M.; Li, Hsiu-Ling; Miniaci, Maria Concetta; Kandel, Eric R.; Choi, Yun-Beom

    2011-01-01

    Loss of the Fragile X mental retardation protein (FMRP) is associated with presumed postsynaptic deficits in mouse models of Fragile X syndrome. However, the possible presynaptic roles of FMRP in learning-related plasticity have received little attention. As a result, the mechanisms whereby FMRP influences synaptic function remain poorly…

  8. Transcriptional Analysis of a Whole-Body Form of Long-Term Habituation in "Aplysia Californica"

    Science.gov (United States)

    Holmes, Geraldine; Herdegen, Samantha; Schuon, Jonathan; Cyriac, Ashly; Lass, Jamie; Conte, Catherine; Calin-Jageman, Irina E.; Calin-Jageman, Robert J.

    2015-01-01

    Habituation is the simplest form of learning, but we know little about the transcriptional mechanisms that encode long-term habituation memory. A key obstacle is that habituation is relatively stimulus-specific and is thus encoded in small sets of neurons, providing poor signal/noise ratios for transcriptional analysis. To overcome this obstacle,…

  9. Reexamination of the gill withdrawal reflex of Aplysia californica Cooper (Gastropoda; Opisthobranchia).

    Science.gov (United States)

    Leonard, J L; Edstrom, J; Lukowiak, K

    1989-06-01

    The gill withdrawal reflex (GWR), an important model system for neural mechanisms of learning, varies in form and amplitude within as well as between preparations and is therefore a heterogeneous collection of action patterns, not a reflex. At least 4 action patterns occur in response to mechanical stimulation of the siphon. It is often impossible to categorize a particular movement unambiguously. All may occur spontaneously. Gill movements may be described as combinations of 10 actions; 4 involving vein movements are described here. All actions and action patterns can occur in preparations lacking the central nervous system. Some vein movements may generate considerable force without markedly altering gill area. It is suggested that this explains why some early studies failed to identify the important role of the peripheral nervous system in the GWR. Studies based on the assumption that the GWR involves a single type of movement controlled by cells of the parietovisceral ganglion require reevaluation. PMID:2544202

  10. Taxonomy Icon Data: Kuroda's sea hare [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available .png Aplysia_kurodai_S.png Aplysia_kurodai_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Aplysia+k...urodai&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Aplysia+kurodai&t=NL http://biosciencedbc.jp/taxonomy..._icon/icon.cgi?i=Aplysia+kurodai&t=S http://biosciencedbc.jp/taxonomy_icon/i...con.cgi?i=Aplysia+kurodai&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=14 ...

  11. Da Aplysia à constituição: evolução de conceitos na análise do comportamento From Aplysia to the constitution: evolution of concepts in behavior analysis

    Directory of Open Access Journals (Sweden)

    João Claudio Todorov

    2004-01-01

    Full Text Available Objetivou-se apresentar a evolução de conceitos na análise do comportamento, especialmente nos trabalhos de Skinner, desde a definição do conceito de operante, de contingência de reforço, até os processos de seleção por conseqüências, seguindo o desenvolvimento de uma linguagem teórica que abarca desde o comportamento de moluscos até o texto da Constituição, enquanto metacontingência. Os trabalhos iniciais de Skinner usavam a linguagem desenvolvida por Pavlov no estudo de reflexos condicionados para abranger todo o comportamento. De sua dissertação de doutorado até os trabalhos publicados nos anos 1980, Skinner evoluiu e com ele toda a análise do comportamento, que hoje usa a mesma linguagem mais sofisticada para abordar temas complexos como práticas culturais e a sobrevivência de culturas.This work presents the evolution of concepts in behavior analysis, especially in the writings of Skinner, from the definition of operant behavior and reinforcement contingency to processes of selection by consequences, following the development of a conceptual language that covers both the behavior of molluscs and the metacontingencies included in the constitution of a country. Skinner's first papers used the terminology developed by Pavlov in his studies of conditioned reflexes to deal with behavior in general. From Skinner's doctoral dissertation to the papers published in the 80's there was an evolution, followed by the field of behavior analysis, which today uses the same, sophisticated language to deal with complex issues like cultural practices and the survival of cultures.

  12. From Aplysia to the constitution: evolution of concepts in behavior analysis / Da Aplysia à constituição: evolução de conceitos na análise do comportamento

    Directory of Open Access Journals (Sweden)

    João Claudio Todorov

    2004-01-01

    Full Text Available This work presents the evolution of concepts in behavior analysis, especially in the writings of Skinner, from the definition of operant behavior and reinforcement contingency to processes of selection by consequences, following the development of a conceptual language that covers both the behavior of molluscs and the metacontingencies included in the constitution of a country. Skinner's first papers used the terminology developed by Pavlov in his studies of conditioned reflexes to deal with behavior in general. From Skinner's doctoral dissertation to the papers published in the 80's there was an evolution, followed by the field of behavior analysis, which today uses the same, sophisticated language to deal with complex issues like cultural practices and the survival of cultures.

  13. MOLECULAR-BIOLOGY OF CLOSTRIDIAL TOXINS - EXPRESSION OF MESSENGER-RNAS ENCODING TETANUS AND BOTULINUM NEUROTOXINS IN APLYSIA NEURONS

    NARCIS (Netherlands)

    MOCHIDA, S; POULAIN, B; EISEL, U; BINZ, T; KURAZONO, H; NIEMANN, H; TAUC, L

    1990-01-01

    mRNAs encoding the light chain of tetanus and botulinum neurotoxins were transcribed, in vitro, from the cloned and specifically truncated genes of Clostridium tetani and Clostridium botulinum, respectively, and injected into presynaptic identified cholinergic neurons of the buccal ganglia of Aplysi

  14. Spontaneous transmitter release is critical for the induction of long-term and intermediate-term facilitation in Aplysia

    OpenAIRE

    Jin, Iksung; Puthanveettil, Sathya; Udo, Hiroshi; Karl, Kevin; Kandel, Eric R.; Hawkins, Robert D.

    2012-01-01

    Long-term plasticity can differ from short-term in recruiting the growth of new synaptic connections, a process that requires the participation of both the presynaptic and postsynaptic components of the synapse. How does information about synaptic plasticity spread from its site of origin to recruit the other component? The answer to this question is not known in most systems. We have investigated the possible role of spontaneous transmitter release as such a transsynaptic signal. Until recen...

  15. Myogenesis in Aplysia californica (Cooper, 1863) (Mollusca, Gastropoda, Opisthobranchia) with special focus on muscular remodeling during metamorphosis

    DEFF Research Database (Denmark)

    Wollesen, Tim; Wanninger, Andreas; Klussmann-Kolb, Annette

    2008-01-01

    postmetamorphic stages exhibit only few congruencies with other gastropod taxa investigated to date, which is probably due to common larval but different adult life styles within gastropods. Accordingly, this study provides further evidence for morphological plasticity in gastropod myogenesis and stresses the...

  16. Structural studies of the 'Aplysia Brasiliana' and 'Dermochelis Coriacea' myoglobins by optical and electron paramagnetic resonance techniques

    International Nuclear Information System (INIS)

    The myoglobins of 'Applysia Brasiliana' (MbApB) and of the sea turtle 'Dermochelis Coriacea' (MbT) are studied with special attention devoted to the acid-alkalyne transition (AAT), the interaction with transition metals and temperature induced conformational changes in order to characterize structural differences in these proteins. The AAT of MbApB has a pK = 7.2 obtained from the EPR spectra of Fe3+ at g (perpendicular) = 5.83 and a pK = 7.5 obtained from optical absorption (lambda = 590 nm). The EPR Spectrum of Fe3+ at alkalyne pH shows a rhombic distortion of the ion crystal field which is in agreement with the absence in this protein of the distal histidine residue. The ESR lines associated with the low spin configuration are considerably broadened. This effect can be explained by fluctuations on the heme position relative to the symmetry axis. MbApB forms complexes with both Cu2+ and Mn2+ only one binding site is obtained for both metals in the protein. This site probably has common ligands for mN2+ and Cu2+ as the binding is competitive, suggesting also the at the Cu2+ complex is more stable than the Mn2+ one (K sub(A) sup(M) sub(n2+)) = (11,5 + - 0,8).103M-1. (Author)

  17. DIETARY NITROGEN AVAILABILITY IN MACROALGAE AFFECTS GROWTH OF THE SEA HARE APLYSIA CALIFORNICA (OPISTHOBRANCHIA:ANASPIDEA). (R830414)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  18. Arrangement of radial actin bundles in the growth cone of Aplysia bag cell neurons shows the immediate past history of filopodial behavior

    OpenAIRE

    Katoh, Kaoru; Hammar, Katherine; Peter J S Smith; Oldenbourg, Rudolf

    1999-01-01

    Filopodia that protrude forward from the lamellipodium, located at the leading edge of a neuronal growth cone, are needed to guide the extension of a nerve cell. At the core of each filopodium an actin bundle forms and grows into the lamellipodium. By using kymographs of time-lapse polarized light images we examined the relationship between the behavior of the filopodia, the actin bundles immediately proximal to the filopodia, and the shapes and composition of actin bundles in the whole lamel...

  19. Sequencing of proteins from two-dimensional gels by using in situ digestion and transfer of peptides to polyvinylidene difluoride membranes: application to proteins associated with sensitization in Aplysia.

    OpenAIRE

    Kennedy, T. E.; Gawinowicz, M A; Barzilai, A; Kandel, E R; Sweatt, J D

    1988-01-01

    We have developed a method for obtaining partial internal amino acid sequence data from proteins isolated directly from preparative two-dimensional polyacrylamide gels. Proteins from a crude cell homogenate are separated using preparative two-dimensional polyacrylamide gel electrophoresis. Then, the gel is stained with Coomassie blue and the protein spots of interest are cut out. The in situ protein is digested with Staphylococcus aureus V8 protease in a second polyacrylamide gel and the pept...

  20. Enhancement of synchronization in a hybrid neural circuit by spike timing dependent plasticity

    OpenAIRE

    Nowotny, Thomas; Zhigulin, Valentin P.; Selverston, Allan I; Abarbanel, Henry D.I.; Rabinovich, Mikhail I.

    2003-01-01

    Synchronization of neural activity is fundamental for many functions of the brain. We demonstrate that spike-timing dependent plasticity (STDP) enhances synchronization (entrainment) in a hybrid circuit composed of a spike generator, a dynamic clamp emulating an excitatory plastic synapse, and a chemically isolated neuron from the Aplysia abdominal ganglion. Fixed-phase entrainment of the Aplysia neuron to the spike generator is possible for a much wider range of frequency ratios and is more ...

  1. Dicty_cDB: Contig-U10198-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 0.28 EF042304_1( EF042304 |pid:none) Aplysia californica NRAG7 protein ... 39 0....042305_1( EF042305 |pid:none) Aplysia californica NRAG8 protein ... 34 9.0 CP0007...e) Taterapox virus strain Dahomey 19... 40 0.13 AM920436_216( AM920436 |pid:none) Penicillium chrysogenum Wiscon....9 AC130601_15( AC130601 |pid:none) Oryza sativa (japonica cultivar-g... 35 6.9 ( O14686 ) RecName: Full=Histone-lys... str. ATCC 27815, comp... 38 0.018 18 ( AP009180 ) Candidatus Carsonella ruddii PV DNA, complete gen... 42 0

  2. Exploration of the molecular architecture of the orthosteric binding site in the α4β2 nicotinic acetylcholine receptor with analogs of 3-(dimethylamino)butyl dimethylcarbamate (DMABC) and 1-(pyridin-3-yl)-1,4-diazepane

    DEFF Research Database (Denmark)

    Bach, Tinna Brøbech; Jensen, Anders A.; Petersen, Jette G.;

    2015-01-01

    the α4-β2 nAChR interface and by surface plasmon resonance biosensor analysis of binding of the compounds to acetylcholine-binding proteins, where they exhibit preference for Lymnaea stagnalis ACh binding protein (Ls-AChBP) over the Aplysia california ACh binding protein (Ac-AChBP). These results...

  3. Isoform Specificity of Protein Kinase Cs in Synaptic Plasticity

    Science.gov (United States)

    Sossin, Wayne S.

    2007-01-01

    Protein kinase Cs (PKCs) are implicated in many forms of synaptic plasticity. However, the specific isoform(s) of PKC that underlie(s) these events are often not known. We have used "Aplysia" as a model system in order to investigate the isoform specificity of PKC actions due to the presence of fewer isoforms and a large number of documented…

  4. Chemical composition of inks of diverse marine molluscs suggests convergent chemical defenses.

    Science.gov (United States)

    Derby, Charles D; Kicklighter, Cynthia E; Johnson, P M; Zhang, Xu

    2007-05-01

    Some marine molluscs, notably sea hares, cuttlefish, squid, and octopus, release ink when attacked by predators. The sea hare Aplysia californica releases secretions from the ink gland and opaline gland that protect individuals from injury or death from predatory spiny lobsters through a combination of mechanisms that include chemical deterrence, sensory disruption, and phagomimicry. The latter two mechanisms are facilitated by millimolar concentrations of free amino acids (FAA) in sea hare ink and opaline, which stimulate the chemosensory systems of predators, ultimately leading to escape by sea hares. We hypothesize that other inking molluscs use sensory disruption and/or phagomimicry as a chemical defense. To investigate this, we examined concentrations of 21 FAA and ammonium in the defensive secretions of nine species of inking molluscs: three sea hares (Aplysia californica, Aplysia dactylomela, Aplysia juliana) and six cephalopods (cuttlefish: Sepia officinalis; squid: Loligo pealei, Lolliguncula brevis, Dosidicus gigas; octopus: Octopus vulgaris, Octopus bimaculoides). We found millimolar levels of total FAA and ammonium in these secretions, and the FAA in highest concentration were taurine, aspartic acid, glutamic acid, alanine, and lysine. Crustaceans and fish, which are major predators of these molluscs, have specific receptor systems for these FAA. Our chemical analysis supports the hypothesis that inking molluscs have the potential to use sensory disruption and/or phagomimicry as a chemical defense. PMID:17393278

  5. Chronically Increased G[subscript s][alpha] Signaling Disrupts Associative and Spatial Learning

    Science.gov (United States)

    Bourtchouladze, Rusiko; Patterson, Susan L.; Kelly, Michele P.; Kreibich, Arati; Kandel, Eric R.; Abel, Ted

    2006-01-01

    The cAMP/PKA pathway plays a critical role in learning and memory systems in animals ranging from mice to "Drosophila" to "Aplysia." Studies of olfactory learning in "Drosophila" suggest that altered expression of either positive or negative regulators of the cAMP/PKA signaling pathway beyond a certain optimum range may be deleterious. Here we…

  6. Molecular Biology of Learning: Modulation of Transmitter Release.

    Science.gov (United States)

    Kandel, Eric R.; Schwartz, James H.

    1982-01-01

    Describes how a behavioral system in Aplysia (marine snail) can be used to examine mechanisms of several forms of learning at different levels of analysis: behavioral, cell-physiological, ultrastructural, and molecular. Focusing on short-term sensitization, suggests how molecular mechanisms can be extended to explain long-term memory and classical…

  7. Activity-Dependent Calpain Activation Plays a Critical Role in Synaptic Facilitation and Post-Tetanic Potentiation

    Science.gov (United States)

    Khoutorsky, Arkady; Spira, Micha E.

    2009-01-01

    Synaptic facilitation and post-tetanic potentiation (PTP) are believed to necessitate active regeneration of the release machinery and supply of synaptic vesicles to a ready-releasable site. The prevailing hypothesis assumes that synapsins play pivotal roles in these processes. Using a cholinergic synapse formed between cultured "Aplysia" neurons…

  8. Differential Role of Inhibition in Habituation of Two Independent Afferent Pathways to a Common Motor Output

    Science.gov (United States)

    Bristol, Adam S.; Carew, Thomas J.

    2005-01-01

    Many studies of the neural mechanisms of learning have focused on habituation, a simple form of learning in which a response decrements with repeated stimulation. In the siphon-elicited siphon withdrawal reflex (S-SWR) of the marine mollusk "Aplysia," the prevailing view is that homosynaptic depression of primary sensory afferents underlies…

  9. Proximate composition of marine invertebrates from tropical coastal waters, with emphasis on the relationship between nitrogen and protein contents

    OpenAIRE

    Graciela S Diniz; Elisabete Barbarino; João Oiano-Neto; Sidney Pacheco; Sergio O. Lourenço

    2014-01-01

    The chemical profiles of Desmapsamma anchorata, Hymeniacidon heliophila (Porifera), Bunodosoma caissarum, Renilla muelleri (Cnidaria), Aplysia brasiliana, Eledone massyae, Isognomon bicolor (Mollusca), Echinaster brasiliensis, Echinometra lucunter, Holothuria grisea, Lytechinus variegatus (Echinodermata), and Phallusia nigra (Chordata) were determined. Hydrosoluble protein was the most abundant class of substances for all species, except for the ascidian Phallusia nigra, in which the carbohyd...

  10. Dicty_cDB: Contig-U15013-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available es promelas Whole (... 46 3.6 1 ( CK324443 ) ACA_CNS_N-9-D12.G Aplysia californica cDNA ampl...if... 46 3.6 1 ( FF075622 ) G1045P325RJ4.T0 Aplysia californica Pooled Normal... 46 3.6 1 ( AY394...817_257( CP000817 |pid:none) Lysinibacillus sphaericus C3-41,... 44 0.014 CP000712_1756( CP000712 |pid:none) Pseudomona...ibacter turnerae T7901, ... 38 0.77 CP000817_3160( CP000817 |pid:none) Lysinibacillus s...4 2.4 2 ( AC020698 ) Homo sapiens BAC clone RP11-45F23 from 4, complet... 36 2.9 5 ( BW158625 ) Ciona in

  11. Do Different Neurons Age Differently? Direct Genome-Wide Analysis of Aging in Single Identified Cholinergic Neurons

    OpenAIRE

    Moroz, Leonid L.; Kohn, Andrea B.

    2010-01-01

    Aplysia californica is a powerful experimental system to study the entire scope of genomic and epigenomic regulation at the resolution of single functionally characterized neurons and is an emerging model in the neurobiology of aging. First, we have identified and cloned a number of evolutionarily conserved genes that are age-related, including components of apoptosis and chromatin remodeling. Second, we performed gene expression profiling of different identified cholinergic neurons between y...

  12. Carbachol can be released at a cholinergic ganglionic synapse as a false transmitter.

    OpenAIRE

    Baux, G; Tauc, L

    1983-01-01

    Carbachol was injected into a presynaptic cholinergic neuron in the buccal ganglion of Aplysia and the quantal aspects of the Cl- -dependent postsynaptic response to a prolonged stimulation were analyzed by a statistical fluctuation method. The calculated amplitude of the miniature postsynaptic current was increased with respect to control. Statistical fluctuation analysis was also used to analyze the postsynaptic response obtained during ionophoretic application of acetylcholine and carbacho...

  13. Synapse- and Stimulus-Specific Local Translation During Long-Term Neuronal Plasticity

    OpenAIRE

    Wang, Dan Ohtan; Kim, Sang Mok; Zhao, Yali; Hwang, Hongik; Miura, Satoru K.; Sossin, Wayne S.; Martin, Kelsey C.

    2009-01-01

    Long-term memory and synaptic plasticity require changes in gene expression and yet can occur in a synapse-specific manner. mRNA localization and regulated translation at synapses are thus critical for establishing synapse specificity. Using live cell microscopy of photoconvertible fluorescent protein translational reporters, we directly visualized local translation at synapses during long-term facilitation of Aplysia sensory-motor synapses. Translation of the reporter required multiple appli...

  14. Presynaptic transmitter content controls the number of quanta released at a neuro-neuronal cholinergic synapse.

    OpenAIRE

    Poulain, B; Baux, G; Tauc, L

    1986-01-01

    In the buccal ganglion of Aplysia the overloading of the cholinergic presynaptic neuron by exogenous acetylcholine (AcCho) led to an enhancement of the postsynaptic response. The deprivation of choline in the presynaptic neuron by extra- and/or intracellularly applied choline oxidase to prevent AcCho synthesis resulted in a decrease of the postsynaptic response. In both cases, the size of the calculated miniature postsynaptic current (i.e., the size of the quantum) remained unchanged. It was ...

  15. Spatial Regulation of Gene Expression in Neurons During Synapse Formation and Synaptic Plasticity

    OpenAIRE

    Kim, Sangmok

    2013-01-01

    mRNA localization and regulated translation allow individual neurons to locally regulate the proteome of each of their many subcellular compartments. To investigate the spatial regulation of gene expression during synaptic plasticity, we used a translational reporter system to demonstrate synapse- and stimulus-specific translation during long-term facilitation of Aplysia sensory-motor synapse. These studies revealed a role for a retrograde signal from the postsynaptic motor neuron in regulati...

  16. Opposite actions of nitric oxide on cholinergic synapses: which pathways?

    OpenAIRE

    Mothet, J P; Fossier, P; Tauc, L; Baux, G

    1996-01-01

    Nitric oxide (NO) produced opposite effects on acetylcholine (ACh) release in identified neuroneuronal Aplysia synapses depending on the excitatory or the inhibitory nature of the synapse. Extracellular application of the NO donor, SIN-1, depressed the inhibitory postsynaptic currents (IPSCs) and enhanced the excitatory postsynaptic currents (EPSCs) evoked by presynaptic action potentials (1/60 Hz). Application of a membrane-permeant cGMP analog mimicked the effect of SIN-1 suggesting the par...

  17. Protein phosphatase dependent circadian regulation of intermediate-term associative memory

    OpenAIRE

    Michel, Maximilian; Gardner, Jacob S.; Green, Charity L.; Organ, Chelsea L.; Lyons, Lisa C.

    2013-01-01

    The endogenous circadian clock is a principal factor modulating memory across species. Determining the processes through which the circadian clock modulates memory formation is a key issue in understanding and identifying mechanisms to improve memory. We used the marine mollusk Aplysia californica to investigate circadian modulation of intermediate-term memory (ITM) and the mechanisms through which the circadian clock phase specifically suppresses memory using the operant learning paradigm, l...

  18. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    OpenAIRE

    Chang Young Lee; Yi Fan; Rubakhin, Stanislav S.; Sook Yoon; Sweedler, Jonathan V.

    2016-01-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia...

  19. Chemical Neurostimulation Using Pulse Code Modulation (PCM) Microfluidic Chips

    OpenAIRE

    Azizi, Farouk; Lu, Hui; Chiel, Hillel J.; Mastrangelo, Carlos H

    2010-01-01

    We report the implementation of a chemical neurostimulation technique using microfluidic devices. The microfluidic chip in this research is used for the in vitro study of the nervous system of Aplysia californica under localized chemical stimulation. The polydimethylsiloxane (PDMS) device is a one-bit pulse code modulator that digitally controls the concentration of the non-hydrolysable cholinergic agonist carbachol injected directly above a ganglion. The chip was successful in repeatedly and...

  20. Differential role of inhibition in habituation of two independent afferent pathways to a common motor output

    OpenAIRE

    Bristol, Adam S.; Carew, Thomas J.

    2005-01-01

    Many studies of the neural mechanisms of learning have focused on habituation, a simple form of learning in which a response decrements with repeated stimulation. In the siphon-elicited siphon withdrawal reflex (S-SWR) of the marine mollusk Aplysia, the prevailing view is that homosynaptic depression of primary sensory afferents underlies short-term habituation. Here we examined whether this mechanism is also utilized in habituation of the tail-elicited siphon withdrawal reflex (T-SWR), which...

  1. Chronically increased Gsα signaling disrupts associative and spatial learning

    OpenAIRE

    Bourtchouladze, Rusiko; Patterson, Susan L.; Kelly, Michele P.; Kreibich, Arati; Kandel, Eric R.; Abel, Ted

    2006-01-01

    The cAMP/PKA pathway plays a critical role in learning and memory systems in animals ranging from mice to Drosophila to Aplysia. Studies of olfactory learning in Drosophila suggest that altered expression of either positive or negative regulators of the cAMP/PKA signaling pathway beyond a certain optimum range may be deleterious. Here we provide genetic evidence of the behavioral and physiological effects of increased signaling through the cAMP/PKA pathway in mice. We have generated transgeni...

  2. CREB-binding protein controls response to cocaine by acetylating histones at the fosB promoter in the mouse striatum

    OpenAIRE

    Levine, Amir A.; Guan, Zhonghui; Barco, Angel; Xu, Shiqin; Kandel, Eric R.; Schwartz, James H.

    2005-01-01

    Remodeling chromatin is essential for cAMP-regulated gene expression, necessary not only for development but also for memory storage and other enduring mental states. Histone acetylation and deacetylation mediate long-lasting forms of synaptic plasticity in Aplysia as well as cognition in mice. Here, we show that histone acetylation by the cAMP-response element binding protein (CREB)-binding protein (CBP) mediates sensitivity to cocaine by regulating expression of the fosB gene and its splice...

  3. The CPEB3 Protein Is a Functional Prion that Interacts with the Actin Cytoskeleton

    OpenAIRE

    Joseph S. Stephan; Luana Fioriti; Nayan Lamba; Luca Colnaghi; Kevin Karl; Irina L. Derkatch; Eric R. Kandel

    2015-01-01

    The mouse cytoplasmic polyadenylation element-binding protein 3 (CPEB3) is a translational regulator implicated in long-term memory maintenance. Invertebrate orthologs of CPEB3 in Aplysia and Drosophila are functional prions that are physiologically active in the aggregated state. To determine if this principle applies to the mammalian CPEB3, we expressed it in yeast and found that it forms heritable aggregates that are the hallmark of known prions. In addition, we confirm in the mouse the im...

  4. A strategy to capture and characterize the synaptic transcriptome

    OpenAIRE

    Puthanveettil, Sathyanarayanan V.; Antonov, Igor; Kalachikov, Sergey; Rajasethupathy, Priyamvada; Choi, Yun-Beom; Kohn, Andrea B.; Citarella, Mathew; Yu, Fahong; Karl, Kevin A.; Kinet, Maxime; Morozova, Irina; Russo, James J.; Ju, Jingyue; Moroz, Leonid L.; Kandel, Eric R.

    2013-01-01

    Here we describe a strategy designed to identify RNAs that are actively transported to synapses during learning. Our approach is based on the characterization of RNA transport complexes carried by molecular motor kinesin. Using this strategy in Aplysia, we have identified 5,657 unique sequences consisting of both coding and noncoding RNAs from the CNS. Several of these RNAs have key roles in the maintenance of synaptic function and growth. One of these RNAs, myosin heavy chain, is critical in...

  5. A New Component in Long-Term Synaptic Plasticity: Upregulation of Kinesin in the Pre- and Postsynaptic Neurons of the Gill-Withdrawal Reflex

    OpenAIRE

    Puthanveettil, Sathyanarayanan V.; Monje, Francisco J.; Miniaci, Maria Concetta; Choi, Yun-Beom; Karl, Kevin A.; Khandros, Eugene; Gawinowicz, Mary Ann; Sheetz, Michael P; Kandel, Eric R.

    2008-01-01

    To explore how gene products, required for the initiation of synaptic growth, move from the cell body of the sensory neurons to its presynaptic terminals, and from the cell body of the motor neuron to its postsynaptic dendritic spines, we have searched for anterograde transport machinery in both the sensory and motor neurons of the gill-withdrawal reflex of Aplysia. We found that the induction of long-term facilitation (LTF) by repeated applications of serotonin, a modulatory transmitter rele...

  6. Laminar stream of detergents for subcellular neurite damage in a microfluidic device: a simple tool for the study of neuroregeneration

    Science.gov (United States)

    Lee, Chang Young; Romanova, Elena V.; Sweedler, Jonathan V.

    2013-06-01

    Objective. The regeneration and repair of damaged neuronal networks is a difficult process to study in vivo, leading to the development of multiple in vitro models and techniques for studying nerve injury. Here we describe an approach for generating a well-defined subcellular neurite injury in a microfluidic device. Approach. A defined laminar stream of sodium dodecyl sulfate (SDS) was used to damage selected portions of neurites of individual neurons. The somata and neurites unaffected by the SDS stream remained viable, thereby enabling the study of neuronal regeneration. Main results. By using well-characterized neurons from Aplysia californica cultured in vitro, we demonstrate that our approach is useful in creating neurite damage, investigating neurotrophic factors, and monitoring somata migration during regeneration. Supplementing the culture medium with acetylcholinesterase (AChE) or Aplysia hemolymph facilitated the regeneration of the peptidergic Aplysia neurons within 72 h, with longer (p < 0.05) and more branched (p < 0.05) neurites than in the control medium. After the neurons were transected, their somata migrated; intriguingly, for the control cultures, the migration direction was always away from the injury site (7/7). In the supplemented cultures, the number decreased to 6/8 in AChE and 4/8 in hemolymph, with reduced migration distances in both cases. Significance. The SDS transection approach is simple and inexpensive, yet provides flexibility in studying neuroregeneration, particularly when it is important to make sure there are no retrograde signals from the distal segments affecting regeneration. Neurons are known to not only be under tension but also balanced in terms of force, and the balance is obviously disrupted by transection. Our experimental platform, verified with Aplysia, can be extended to mammalian systems, and help us gain insight into the role that neurotrophic factors and mechanical tension play during neuronal regeneration.

  7. High Frequency Stimulation Selectively Blocks Different Types of Fibers in Frog Sciatic Nerve

    OpenAIRE

    Joseph, Laveeta; Butera, Robert J

    2011-01-01

    Conduction block using high frequency alternating current (HFAC) stimulation has been shown to reversibly block conduction through various nerves. However, unlike simulations and experiments on myelinated fibers, prior experimental work in our lab on the sea-slug, Aplysia, found a nonmonotonic relationship between frequency and blocking thresholds in the unmyelinated fibers. To resolve this discrepancy, we investigated the effect of HFAC waveforms on the compound action potential of the sciat...

  8. Cycle-to-cycle variability as an optimal behavioral strategy

    OpenAIRE

    Brezina, Vladimir; Proekt, Alex; Weiss, Klaudiusz R.

    2006-01-01

    Aplysia feeding behavior is highly variable from cycle to cycle. In some cycles, when the variability causes a mismatch between the animal's movements and the requirements of the feeding task, the variability makes the behavior unsuccessful. We propose that the behavior is variable nevertheless because the variability serves a higher-order functional purpose. When the animal is faced with a new and only imperfectly known feeding task in each cycle, the variability implements a trial-and-error...

  9. Reaction sequence and molecular mass of a Cl(-)-translocating P-type ATPase.

    OpenAIRE

    Gerencser, G A; Zelezna, B

    1993-01-01

    The basolateral membranes of Aplysia californica foregut absorptive cells contain both Cl(-)-stimulated ATPase and ATP-dependent Cl- transport activities, and each was inhibited by orthovanadate. Both of these orthovanadate-sensitive activities were reconstituted into proteoliposomes. The reaction sequence kinetics were determined by [gamma-32P]ATP-induced phosphorylation of the reconstituted Cl- pump. Rapid phosphorylation and dephosphorylation kinetics of acyl phosphate bonding were confirm...

  10. In vitro antibacterial, alpha-amylase inhibition potential of three nudibranchs extracts from South East coast of India

    Institute of Scientific and Technical Information of China (English)

    Giji Sadhasivam; Arumugam Muthuvel; Wanjale Mrunal Vitthal; Abirami Pachaiyappan; Mohan Kumar; Balasubramanian Thangavel

    2013-01-01

    Objective: To study the antibacterial and antiamylase properties of methanol and acetone extracts of nudibranchs including Bursatella leachii (B. leachii), Kalinga ornata (K. ornata),Aplysia sp. Methods: Crude methanol and acetone extracts of sea slugs were tested for inhibition of fish bacterial pathogens' growth through disc diffusion method. The activity was measured based on the formation of inhibition zone around the disc impregnated with crude extracts. The α-amylase inhibitory effect was also measured calorimetrically. The chemical fingerprinting of the extract was recorded with HPTLC and GC-MS. Results: The solvent extracts of all the three sea slugs showed antibacterial property. The maximum zone of inhibition (>15-20 mm) was recorded for methanol and acetone extracts of K.ornata. The methanol extract of Aplysia sp. exhibited 93% inhibition against α-amylase, following by B. leachii (methanol) 70.6% and K. ornata (methanol) 49.03% inhibition respectively. The acetone extracts didn' t show any notable inhibition. The presence of free amino acids like lysine, aspartic acid, glutamic acid, arginine etc., terpenoids and pigents were confirmed through HPTLC analysis. The presence of siloxanes and propanoic acid were also revealed through GC-MS. Conclusions: This study suggests that further scrutinisation of the B. leachii, K. ornata and Aplysia sp. will pave the way for development of antibacterial and α-amylase inhibitory agent for therapeutic application.

  11. In vitro antibacterial, alpha-amylase inhibition potential of three nudibranchs extracts from South East coast of India

    Directory of Open Access Journals (Sweden)

    Giji Sadhasivam

    2013-10-01

    Full Text Available Objective: To study the antibacterial and antiamylase properties of methanol and acetone extracts of nudibranchs including Bursatella leachii (B. leachii, Kalinga ornata (K. ornata, Aplysia sp. Methods: Crude methanol and acetone extracts of sea slugs were tested for inhibition of fish bacterial pathogens' growth through disc diffusion method. The activity was measured based on the formation of inhibition zone around the disc impregnated with crude extracts. The α-amylase inhibitory effect was also measured calorimetrically. The chemical fingerprinting of the extract was recorded with HPTLC and GC-MS. Results: The solvent extracts of all the three sea slugs showed antibacterial property. The maximum zone of inhibition (>15-20 mm was recorded for methanol and acetone extracts of K. ornata. The methanol extract of Aplysia sp. exhibited 93% inhibition against α-amylase, following by B. leachii (methanol 70.6% and K. ornata (methanol 49.03% inhibition respectively. The acetone extracts didn' t show any notable inhibition. The presence of free amino acids like lysine, aspartic acid, glutamic acid, arginine etc., terpenoids and pigents were confirmed through HPTLC analysis. The presence of siloxanes and propanoic acid were also revealed through GC-MS. Conclusions: This study suggests that further scrutinisation of the B. leachii, K. ornata and Aplysia sp. will pave the way for development of antibacterial and α-amylase inhibitory agent for therapeutic application.

  12. Dicty_cDB: Contig-U15937-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available qyylkihynqfih*fqtqyqlknililiihy lnhyklhyhtiyiy*llqnnglihlql**d*lifmklvkvlifqnqlililvvviititi iiiiimvf*liiif...liihy lnhyklhyhtiyiy*llqnnglihlql**d*lifmklvkvlifqnqlililvvviititi iiiiimvf*liiif...27652 ) 1095454031086 Global-Ocean-Sampling_GS-26-01-01-1... 48 1.2 1 ( GD213327 ) G1045P382FC12.T1 Aplysia califo...T 9215, complete g... 48 1.2 1 ( AC220074 ) Heliconius erato clone BBAM-12K4, WORKING DRAFT S... 40 1.2 5 ( AC007991 ) Homo sa...iva Japonica Group genomic DNA, chromoso... 42 2.6 3 ( AC193804 ) Heliconius erato clone BBAM-38A20,

  13. Dicty_cDB: Contig-U04328-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 5 0.006 AY952205_1( AY952205 |pid:none) Aplysia californica beta-catenin m... 40 0.21 AY539935_1( AY539935 |...nln*smsryryve*yr*keyrtkis*wyn*ykk*ne*nfcnafik cysykrrlfiinamw*rirgilyneisssvnngfksrrlf*in...ete ... 42 0.013 18 ( EF710654 ) Glyptapanteles indiensis clone BAC 10J2, compl.... 46 0.39 5 ( AC116982 ) Dictyostelium discoideum chromosome 2 map 3622643... 34 0.40 12 ( CR925677 ) Ehrlichia rumina...WORKING DRAFT... 34 1.2 9 ( AY689436 ) Deerpox virus W-848-83, complete genome. 38 1.4 10 ( BA000021 ) Wigglesworthia glossin

  14. Infrared neural stimulation (INS) inhibits electrically evoked neural responses in the deaf white cat

    Science.gov (United States)

    Richter, Claus-Peter; Rajguru, Suhrud M.; Robinson, Alan; Young, Hunter K.

    2014-03-01

    Infrared neural stimulation (INS) has been used in the past to evoke neural activity from hearing and partially deaf animals. All the responses were excitatory. In Aplysia californica, Duke and coworkers demonstrated that INS also inhibits neural responses [1], which similar observations were made in the vestibular system [2, 3]. In deaf white cats that have cochleae with largely reduced spiral ganglion neuron counts and a significant degeneration of the organ of Corti, no cochlear compound action potentials could be observed during INS alone. However, the combined electrical and optical stimulation demonstrated inhibitory responses during irradiation with infrared light.

  15. Synthetic Efforts for Stereo Structure Determination of Cytotoxic Marine Natural Product Pericosines as Metabolites of Periconia sp. from Sea Hare

    Directory of Open Access Journals (Sweden)

    Masao Arimoto

    2008-03-01

    Full Text Available Pericosines are unique C7 cyclohexenoid metabolites of Periconia byssoides OUPS-N133 fungus that was originally isolated from the sea hare, Aplysia kurodai. Pericosines show significant in vitro cytotoxicity against P388 lymphocytic leukemia cells. Pericosine A, in particular, shows the most potent activity and significant in vivo antitumor activity against P388 cells. Thus, pericosines are promising candidates for seed compounds of anticancer drugs. However, before the total syntheses of pericosines were accomplished, their stereo structures could not be determined by spectral analyses because they have multifunctionalized cyclohexenoid structures with torsional strain. In this review, synthetic efforts for pericosines in this decade are surveyed.

  16. A brief retraining regulates the persistence and lability of a long-term memory

    OpenAIRE

    Levitan, David; Twitto, Rachel; Levy, Roi; Lyons, Lisa C.; Susswein, Abraham J.

    2010-01-01

    An experience extending the persistence of a memory after training Aplysia californica with inedible food also allows a consolidated memory to become sensitive to consolidation blockers. Long-term (24 h) memory is initiated by 5 min of training and is dependent on protein synthesis during the first few hours after training. By contrast, a more persistent (48 h) memory is dependent on a longer training session and on a later round of protein synthesis. When presented 24 h after training, a 3-m...

  17. 細胞外電位と細胞内電位の微分波形との関係

    OpenAIRE

    猪股, 孝四郎; 太田, 勲; 倉橋, 昌司; イノマタ, コウシロウ; オオタ, イサオ; クラハシ, マサシ; Koshiro, INOMATA; Isao, OOTA; Masashi, KURAHASHI

    2005-01-01

    Intracellular and extracellular potentials from one cell that spontaneously discharged in the Aplysia abdominal ganglion (R10, 11, 12, L10, 12, 13) were recorded simultaneously and summarized as follows: 1. The amplitude of intracellular action potential was 50-70mV and the amplitude of extracellular potential was about 0.3mV. 2. The pattern of extracellular action potential was similar to the differential pattern of intracellular action potential. 3. In the time course, there was a time lag ...

  18. Axonal transport of eukaryotic translation elongation factor 1α mRNA couples transcription in the nucleus to long-term facilitation at the synapse

    OpenAIRE

    Giustetto, Maurizio; Hegde, Ashok N.; Si, Kausik; Casadio, Andrea; Inokuchi, Kaoru; Pei, Wanzheng; Kandel, Eric R.; Schwartz, James H.

    2003-01-01

    Long-term synaptic plasticity requires both gene expression in the nucleus and local protein synthesis at synapses. The effector proteins that link molecular events in the cell body with local maintenance of synaptic strength are not known. We now show that treatment with serotonin (5-HT) that produces long-term facilitation induces the Aplysia eukaryotic translation elongation factor 1α (Ap-eEF1A) as a late gene that might serve this coupling function in sensory neurons. Although the transla...

  19. Neuralized1 Activates CPEB3: A Novel Function of Ubiquitination in Synaptic Plasticity and Memory Storage

    OpenAIRE

    Pavlopoulos, Elias; Trifilieff, Pierre; Chevaleyre, Vivien; Fioriti, Luana; Zairis, Sakellarios; Pagano, Andrew; Malleret, Gaël; Kandel, Eric R.

    2011-01-01

    The cytoplasmic polyadenylation element-binding protein 3 (CPEB3), a regulator of local protein synthesis, is the mouse homologue of ApCPEB, a functional prion protein in Aplysia. Here, we provide evidence that CPEB3 is activated by Neuralized1, an E3 ubiquitin ligase. In hippocampal cultures, CPEB3 activated by Neuralized1-mediated ubiquitination leads both to the growth of new dendritic spines and to an increase of the GluA1 and GluA2 subunits of AMPA receptors, two CPEB3 targets essential ...

  20. A strategy to capture and characterize the synaptic transcriptome

    Science.gov (United States)

    Puthanveettil, Sathyanarayanan V.; Antonov, Igor; Kalachikov, Sergey; Rajasethupathy, Priyamvada; Choi, Yun-Beom; Kohn, Andrea B.; Citarella, Mathew; Yu, Fahong; Karl, Kevin A.; Kinet, Maxime; Morozova, Irina; Russo, James J.; Ju, Jingyue; Moroz, Leonid L.; Kandel, Eric R.

    2013-01-01

    Here we describe a strategy designed to identify RNAs that are actively transported to synapses during learning. Our approach is based on the characterization of RNA transport complexes carried by molecular motor kinesin. Using this strategy in Aplysia, we have identified 5,657 unique sequences consisting of both coding and noncoding RNAs from the CNS. Several of these RNAs have key roles in the maintenance of synaptic function and growth. One of these RNAs, myosin heavy chain, is critical in presynaptic sensory neurons for the establishment of long-term facilitation, but not for its persistence. PMID:23589870

  1. Dicty_cDB: Contig-U01095-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available re E Sequences producing significant alignments: (bits) Value N ( C25564 ) Dictyostelium discoideum slug cDN...,291 total letters Score E Sequences producing significant alignments: (bits) Val...OR373w. 48 0.74 1 ( X62147 ) S.cerevisiae nud1 gene. 48 0.74 1 ( CU928472 ) S.lycopersicum DNA sequence from....74 1 ( GH262396 ) EST_eluc_evq_1006426 elucevq mixed_tissue Esox lu... 48 0.74 1 ( GD205442 ) G1045P347RB11.T1 Aplysia californica...0,864 total letters Searching..................................................done Score E Sequences producing significa

  2. Single Memristor Logic Gates: From NOT to a Full Adder

    OpenAIRE

    Gale, Ella

    2015-01-01

    Memristors have been suggested as a novel route to neuromorphic computing based on the similarity between them and neurons (specifically synapses and ion pumps). The d.c. action of the memristor is a current spike which imparts a short-term memory to the device. Here it is demonstrated that this short-term memory works exactly like habituation (e.g. in \\emph{Aplysia}). We elucidate the physical rules, based on energy conservation, governing the interaction of these current spikes: summation, ...

  3. PKA-activated ApAF–ApC/EBP heterodimer is a key downstream effector of ApCREB and is necessary and sufficient for the consolidation of long-term facilitation

    OpenAIRE

    LEE, Jin-A; Lee, Sue-Hyun; Lee, Changhoon; Chang, Deok-Jin; Lee, Yong; Kim, Hyoung; Cheang, Ye-Hwang; Ko, Hyoung-Gon; Lee, Yong-Seok; Jun, Heejung; Bartsch, Dusan; Kandel, Eric R.; Kaang, Bong-Kiun

    2006-01-01

    Long-term memory requires transcriptional regulation by a combination of positive and negative transcription factors. Aplysia activating factor (ApAF) is known to be a positive transcription factor that forms heterodimers with ApC/EBP and ApCREB2. How these heterodimers are regulated and how they participate in the consolidation of long-term facilitation (LTF) has not, however, been characterized. We found that the functional activation of ApAF required phosphorylation of ApAF by PKA on Ser-2...

  4. Acid phosphatase localization in neurons of Bulla gouldiana (Gastropoda: Opisthobranchia.

    Science.gov (United States)

    Robles, L J; Fisher, S K

    1975-01-01

    The organization of the ganglia and the ultrastructure of the neurons of Bulla gouldiana are similar to those described for other molluscs. Acid phosphatase positive reactions were found in the large pigmented granules, small dense bodies, multivesicular bodies, and Golgi lamellae and associated vesicles. The small dense bodies and multivesicular bodies may be stages in the formation of the larger pigmented granules which are interpreted as lysosomes. Comparison is made between the pigmented granules in Bulla and the lipofuscin bodies of vertebrate neurons. The possible involvement of these pigmented granules in the hyperpolarization of Bulla and Aplysia neurons to light is discussed. PMID:1122539

  5. A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

    Science.gov (United States)

    Lee, Chang Young; Fan, Yi; Rubakhin, Stanislav S.; Yoon, Sook; Sweedler, Jonathan V.

    2016-06-01

    The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns.

  6. Biogeographical homogeneity in the eastern Mediterranean Sea - I: the opisthobranchs (Mollusca: Gastropoda from Lebanon

    Directory of Open Access Journals (Sweden)

    F. CROCETTA

    2013-07-01

    Full Text Available A reviewed knowledge of the opisthobranch species from Lebanon (eastern Mediterranean Sea, based on literature records (scattered throughout various papers published over a period of more than 150 years and recently collected material (1999-2002 within the CEDRE framework and other samples, is presented, yielding a total number of 35 taxa recorded from the Lebanese shores identified to species level. Special emphasis has mainly been given to the alien species, for which scattered notes are also given. The known opisthobranch biota is composed of 22 native (~ 63%, 12 alien (~ 34% and one cryptogenic (~ 3% taxa. Eleven of these (Berthella aurantiaca, B. ocellata, Aplysia fasciata, Felimare picta, Felimida britoi, F. luteorosea, F. purpurea, Phyllidia flava, Dendrodoris grandiflora, D. limbata and Aeolidiella alderi constitute new records for the Lebanese fauna, whilst the examined material of a further seven species (Elysia grandifolia, Pleurobranchus forskalii, Aplysia dactylomela, Bursatella leachii, Syphonota geographica, Goniobranchus annulatus, Flabellina rubrolineata anecdotally cited from Lebanon on the basis of the samples here studied, is here first explained. One additional taxon belonging to the genus Haminoea has been identified to genus level only. Despite the searching effort poning the basis of the material analyzed here, data reported clearly suggest that strong investments are still needed for a better understanding of the eastern Mediterranean opisthobranch fauna.

  7. Dicty_cDB: Contig-U13264-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ... 92 8e-18 DQ119137_1( DQ119137 |pid:none) Aplysia californica nonmuscle myos... 92 ..... 46 1.4 1 ( AC074279 ) Homo sapiens chromosome 3 clone RP11-373L21, WORK... 46 1.4 1 ( AC205032 ) Zea mays chromosome 8 clon...44 5.5 1 ( AC013447 ) Homo sapiens BAC clone RP11-543D5 from 1, complet... 44 5.5 1 ( AC146184 ) Pan troglodytes chromosome 7 clon...e) Arabidopsis thaliana chromosome 1 ... 114 3e-24 AF233886_1( AF233886 |pid:none) Vallisneria natans unconventiona... tabacum Ntmy175 mRNA for... 109 6e-23 CP001323_780( CP001323 |pid:none) Micromona

  8. Dicty_cDB: Contig-U11274-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available .. 48 0.33 3 ( AE002145 ) Ureaplasma parvum serovar 3 str. ATCC 700970 sect... 34 0.48 4 ( AC024947 ) Homo sapiens chromoso...002442 Global-Ocean-Sampling_GS-30-02-01-1... 38 2.4 2 ( FF060991 ) G1045P39RB18.T0 Aplysia californica Pool...275 ;A33219;PC2220;A35443) ankyrin 1, erythrocyte splice... 55 3e-06 CP000529_1934( CP000529 |pid:none) Polaromonas nap...20431_368( AM920431 |pid:none) Penicillium chrysogenum Wisconsi... 55 4e-06 CP001391_88( CP001391 |pid:none)...ma mansoni genome sequen... 52 3e-05 AM920435_347( AM920435 |pid:none) Penicillium chrysogenum Wiscon

  9. Dicty_cDB: Contig-U15944-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available iens c... 47 3e-04 FJ666398_1( FJ666398 |pid:none) Aplysia californica CaM kina... AK292722 |pid:none) Homo sapiens cDNA FLJ76963 complet... 46 7e-04 JC5974( JC5974 )aurora-related kinase 1 ...M920435_108( AM920435 |pid:none) Penicillium chrysogenum Wisconsi... 46 0.001 (Q9FMP5) RecName: Full=Calcium-dependent protein kina...tchensis clone WS02713_O07... 46 0.001 AF506518_1( AF506518 |pid:none) Glycine max receptor-like kina...ne) Kluyveromyces lactis strain NRRL... 45 0.001 (Q54CY9) RecName: Full=Probable myosin light chain kina

  10. Dicty_cDB: SFG127 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available tus tryptophan... 260 1e-68 DQ479389_1( DQ479389 |pid:none) Aplysia californica t...0336.1 Schistosoma mansoni tyrosine hydroxylase (TH) mRNA, complete cds. 42 0.12 2 AP003800 |AP003800.3 Oryza sativa (jap...SF (Link to library) SFG127 (Link to dictyBase) - - - Contig-U13888-1 SFG127Z (Link to Original si... dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U13888-1 Original site URL http://dict...ycdb.biol.tsukuba.ac.jp/CSM/SF/SFG1-B/SFG127Q.Seq.d/ Representative seq. ID SFG127Z (Link to Original si

  11. Dicty_cDB: Contig-U15087-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ic cl... 42 0.35 2 ( AF286894 ) Plasmodium falciparum clone CS016 microsatellite ... 36 0.36 2 ( FF076674 ) G1045P319FB3.T0 Aplysi...telium discoideum slug cDNA, clone SLI670. 40 0.71 2 ( M98854 ) Aplysia californi...ca neuropeptide Y mRNA, complete cds. 46 0.74 2 ( AM688401 ) Entamoeba terrapinae GSS, clone terra265f09.p1k... *** SEQUENCING IN PROGRESS... 40 0.57 2 ( AM676480 ) Entamoeba terrapinae GSS, clone terra120c05.p1k. 38 0....yfrkksk*rk*iifirkcntnrgfisncikf ik*isksfk*in*srisinre***q*ynkwrlir*slnsne**stksikrffkytsn*rw *cfrkif**cfifnn

  12. Dicty_cDB: VHE283 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ) Homo sapiens KIAA0068 mRNA, partial cds. 119 3e-25 AY687629_1( AY687629 |pid:none) Aplysia...ppppplechhph Frame B: lckdfqkessrtivw*yanhigiig*eittfr*egmgylnig**isvglrdhscfgpntf plqrvygtfckygqrd*sgqsswskgtiai...543.1 BB160009B10C07.5 Bee Brain Normalized Library, BB16 Apis mellifera cDNA clone BB160009B10C07 5', mRNA sequen...grv*yssnhidgfedsl*ldlkststigle if*tkq*snhfsnl*l*tcr*iqlyqrgenrfgsidrhdqiigfiddee*nitstnts*d hssrvar...irA) mRNA, complete cds. 1203 0.0 1 EK381364 |EK381364.1 1095469462626 Global-Ocean-Sampling_GS-31-01-01-1P3-1P8KB marine metagen

  13. Dicty_cDB: Contig-U13457-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available s; 5,674,871 total letters Score E Sequences producing significant alignment...nicola strain ... 150 4e-44 D83379_1( D83379 |pid:none) Hemicentrotus pulcherrimus mRNA for re... 159 4e-44 ( P07278 ) RecName: Full...57 2e-09 CP000613_484( CP000613 |pid:none) Rhodospirillum centenum SW, comp... 66...2( CP001193 |pid:none) Rhizobium leguminosarum bv. trif... 50 2e-04 AE005673_1405( AE005673 |pid:none) Caulobacter crescent...=cAMP-dependent protein kinase type II reg... 150 7e-38 AY387673_1( AY387673 |pid:none) Aplysia californica

  14. AcEST: BP911823 [AcEST

    Lifescience Database Archive (English)

    Full Text Available |A4JLF9_BURVG Putative uncharacterized protein OS=Burkh... 33 9.9 tr|Q9NJS6|Q9NJS6_APLKU Octopamine... receptor OS=Aplysia kurodai PE... 33 9.9 tr|Q9NHF3|Q9NHF3_APLCA Octopamine receptor OS=Ap...icant alignments: (bits) Value sp|A4SHP4|OTC_AERS4 Ornithine carbamoyltransferase OS=Aeromonas ... 33 1.2 sp|Q6CQB5|ERFB_KLULA Palmi...C9|B1T6C9_9BURK Putative uncharacterized protein OS=Burkholderia ambifaria MEX-5 GN=BamMEX5DRAFT_3345 PE=3 S...toyltransferase ERF2 OS=Kluyveromyces ... 31 3.4 sp|Q10095|YAOG_SCHPO Uncharacterized protein

  15. Development of a high specific activity radioligand, 125I-LSD, and its application to the study of serotonin receptors

    International Nuclear Information System (INIS)

    125I-Labeled receptor ligands can be synthesized with specific activities exceeding 2000 Ci/mmol, making them nearly 70-fold more sensitive in receptor site assays than (mono) tritiated ligands. We have synthesized and characterized 125I-lysergic acid diethylamide (125I-LSD), the first radioiodinated ligand for serotonin receptor studies. The introduction of 125I at the 2 position of LSD increased both the affinity and selectivity of this compound for serotonin 5-HT2 receptors in rat cortex. The high specific activity of 125I-LSD and its high ratio of specific to nonspecific binding make this ligand especially useful for autoradiographic studies of serotonin receptor distribution. We have found that 125I-LSD binds with high affinity to a class of serotonin receptors in the CNS of the marine mollusk Aplysia californica

  16. Dicty_cDB: Contig-U09708-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ricolum subsp. capricolum ATCC 2734... 38 0.012 18 ( BX950229 ) Methanococcus maripal...totagmin-1; AltName: Full=Synaptotag... 44 0.013 AK227322_1( AK227322 |pid:none) Arabidopsis thaliana...K164153_1( AK164153 |pid:none) Mus musculus adult male hippocampu... 43 0.022 (Q9R0N5) RecName: Full=Synap...lo... 40 0.24 EF469241_1( EF469241 |pid:none) Cyclorana alboguttata synaptotagmi... 40 0.24 PC6300( PC6300 ) synap...totagmin-7; AltName: Full=Synaptotag... 38 0.91 U03125_1( U03125 |pid:none) Aplysia californica synap

  17. Eric Kandel: the future of memory.

    Science.gov (United States)

    Kandel, Erik

    2005-04-01

    Watching ice floes glide by on the Hudson River from Eric Kandel's office, one gets a sense of placid reflection tempered by constant action-an apt analogy for Kandel's ability to calmly manage several ongoing projects and commitments at once. In addition to his well-lauded, ongoing research at Columbia University Medical Center's New York State Psychiatric Institute, Kandel has written several books on neurobiology, behavior, and memory. In addition to being a Nobel Laureate Scientist, he is well-known as an editor of the seminal textbook Principles of Neural Science. He and his colleagues are in the midst of working on a new edition of Principles, and he is working on a scientific autobiography. MI sat down with Dr. Kandel and discussed with him a range of topics including childhood and early career influences, intramural research at the NIH, the HHMI, ethical considerations of altering memory and, of course, Aplysia. PMID:15821153

  18. Dicty_cDB: Contig-U04734-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 084 letters) Database: CSM 6905 sequences; 5,674,871 total letters Score E Sequences producing significa...l letters Searching..................................................done Score E Sequences producing significa...romosome 8, D8S0760i, ... 40 1.6 2 ( DJ461309 ) Method for analysing genome using microsatellite ... 40 1.6 2 ( CU570894 ) Zebrafis...e *** SEQUENCING IN PROGRESS... 36 1.7 6 ( AC202225 ) Acyrthosiphon pisum BAC VMRC38-10-A7 (Benaroya R... 36...3 ( BZ496226 ) BONNW19TR BO_1.6_2_KB_tot Brassica oleracea genom... 42 2.5 2 ( GD205352 ) G1045P347FD16.T1 Aplysia californica

  19. Photobacterium swingsii sp. nov., isolated from marine organisms.

    Science.gov (United States)

    Gomez-Gil, Bruno; Roque, Ana; Rotllant, Guiomar; Peinado, Lauro; Romalde, Jesus L; Doce, Alejandra; Cabanillas-Beltrán, Hector; Chimetto, Luciane A; Thompson, Fabiano L

    2011-02-01

    Six Gram-negative coccobacilli were isolated from Pacific oysters (Crassostrea gigas) from Mexico and haemolymph of spider crabs (Maja brachydactyla) from Spain. All of the isolates grew as small green colonies on thiosulphate-citrate-bile salts-sucrose (TCBS) agar and were facultatively anaerobic, oxidase-positive and sensitive to the vibriostatic agent O/129. Repetitive palindromic PCR analysis revealed a high degree of genomic homogeneity among the isolates. Several phenotypic traits differentiated the isolates from the type strains of species of the genus Photobacterium. DNA-DNA relatedness between two representative isolates and their closest phylogenetic neighbours by 16S rRNA gene sequence similarity, Photobacterium aplysiae CAIM 14(T) and Photobacterium frigidiphilum CAIM 20(T), was 44.01-53.85 %. We propose a novel species of the genus Photobacterium to accommodate the six isolates, with the name Photobacterium swingsii sp. nov. The type strain is CAIM 1393(T) (=CECT 7576(T)). PMID:20228205

  20. It's not what it looks like: molecular data fails to substantiate morphological differences in two sea hares (Mollusca, Heterobranchia, Aplysiidae) from southern Brazil

    Science.gov (United States)

    Saad, Luiza de Oliveira; Cunha, Carlo Magenta; Colpo, Karine Delevati; Valdés, Ángel

    2014-12-01

    Species of sea hares have been recognized traditionally based on morphological traits, mainly the radula, external coloration, and reproductive anatomy. However, recent studies have shown substantial color variation in some sea slug species. Molecular data have been successfully used to differentiate morphologically similar species of "opisthobranchs" and resolve questions on the taxonomic value of color. The objective of this paper is to use molecular data in an attempt to elucidate whether specimens of Aplysia brasiliana with distinct colorations and morphologies are actually the same species. To this end, DNA from 14 specimens of A. brasiliana was extracted, including five specimens identified as a distinct morphotype from typical A. brasiliana. Although the two morphotypes have consistent differences in their external morphology and radula, the molecular data confirmed that there are no significant genetic differences between them. This is another example of the need to re-evaluate taxonomic decisions based on morphology in light of molecular evidence.

  1. Dicty_cDB: Contig-U15819-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ... 52 0.12 1 ( AC034257 ) Arabidopsis thaliana chromosome I BAC F11A6 genom... 52 0.12 1 ( AC022492 ) Genomic sequence for...( AP008216 ) Oryza sativa (japonica cultivar-group) genomic DN... 50 0.47 1 ( AK228969 ) Arabidopsis thaliana mRNA for... myos... 411 e-113 CP001323_780( CP001323 |pid:none) Micromonas sp. RCC299 chromosome.....m... 377 e-103 CP001325_574( CP001325 |pid:none) Micromonas sp. RCC299 chromosome... 379 e-103 (Q99MZ6) RecN...137_1( DQ119137 |pid:none) Aplysia californica nonmuscle myos... 340 2e-91 AF319457_1( AF319457 |pid:none) Petroselinum cr

  2. Dicty_cDB: Contig-U15350-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available S1-acp-j-12-0-UI.s1 UI-S-GS1 Euprymna scolo... 96 8e-29 5 ( EH114005 ) RPL-P6-A9 Fifth instar salivary gland...) G1045P393FA2.T1 Aplysia californica Pooled Normal... 98 2e-25 2 ( CO206291 ) WS00910.B21_L22 IS-B-N-A-10 P...9 3e-31 1 ( FC650540 ) CAXW11402.fwd CAXW Lottia gigantea from female go... 100 3e-31 4 ( FC7... 5e-31 4 ( FC713741 ) CAXY8504.fwd CAXY Lottia gigantea from male gonad... 100 5e-31 4 ( FE234214 ) CAPG2700...248775 Cryptosporidium muris (strain RN66)... 96 3e-24 3 ( FD390140 ) 1106162213440

  3. New Mediterranean Biodiversity Records (June 2012

    Directory of Open Access Journals (Sweden)

    A. NICOLAIDOU

    2012-12-01

    Full Text Available The present work reports on the extended distribution of nineteen species in the Mediterranean. These are: Upeneus pori(Fish:Turkey, Bursatella leachii (Mollusca, Opisthobranchia: eastern coast of Spain, Sparisoma cretense (Fish: Ionian coastof Greece, Pseudobryopsis myura (Chlorophyta: Turkey, Aplysia dactylomela (Mollusca, Opisthobranchia: Karpathos island,and Kyklades Archipelago, Greece, Asparagopsis armata and Botryocladia madagascariensis (Rhodophyta: South Peloponnesos,Greece, Oxynotus centrina (Fish: Greece, Caulerpa racemosa var. cylindracea (Chlorophyta , Stypopodium schimperi(Phaeophyta Siganus luridus and Stephanolepis diaspros (Fish Percnon gibbesi (Decapoda, Brachyura (Kyklades Archipelago,Greece, Cerithium scabridum (Mollusca, Prosobranchia: Anavissos: Greece and Cerithium renovatum (Mollusca, Prosobranchia:N. Κriti, Cassiopea andromeda (Scyphomedusa: Rhodos Island, Greece, Abra tenuis (Mollusca Bivalvia: VouliagmeniLake, Greece Lagocephalus lagocephalus (Fish: Calabrian coast, Italy and Plocamopherus ocellatus (Mollusca, Opisthobranchia:İskenderun Bay, Turkey.

  4. Dicty_cDB: Contig-U15821-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available brary Danio re... 48 1.2 1 ( BG515879 ) dad20f01.x1 Wellcome CRC pCS107 tropicalis St10-1... 48 1.2 1 ( BG515006 ) dad...1 ( DC174601 ) Xenopus (Silurana) tropicalis NBRP cDNA clone: st... 48 1.2 1 ( AM596959 ) Paracentrotus livid...AA28AD01.g1 Xenopus tropicalis xthr plasmid l... 48 1.2 1 ( CN105687 ) EC2CAA28AD01.b1 Xenopus tropicalis xthr plasmid... 2 ( BM163498 ) EST566021 PyBS Plasmodium yoelii yoelii cDNA clon... 46 0.55 2 ( GD202904 ) G1045P356RN13.T1 Aplysia californica...ap 215673-... 32 1.1 11 ( CR761837 ) Xenopus tropicalis finished cDNA, clone TGas012o17. 48 1.2 1 ( G41485 )

  5. Changing gears from chemical adhesion of cells to flat substrata toward engulfment of micro-protrusions by active mechanisms

    Science.gov (United States)

    Hai, Aviad; Kamber, Dotan; Malkinson, Guy; Erez, Hadas; Mazurski, Noa; Shappir, Joseph; Spira, Micha E.

    2009-12-01

    Microelectrode arrays increasingly serve to extracellularly record in parallel electrical activity from many excitable cells without inflicting damage to the cells by insertion of microelectrodes. Nevertheless, apart from rare cases they suffer from a low signal to noise ratio. The limiting factor for effective electrical coupling is the low seal resistance formed between the plasma membrane and the electronic device. Using transmission electron microscope analysis we recently reported that cultured Aplysia neurons engulf protruding micron size gold spines forming tight apposition which significantly improves the electrical coupling in comparison with flat electrodes (Hai et al 2009 Spine-shaped gold protrusions improve the adherence and electrical coupling of neurons with the surface of micro-electronic devices J. R. Soc. Interface 6 1153-65). However, the use of a transmission electron microscope to measure the extracellular cleft formed between the plasma membrane and the gold-spine surface may be inaccurate as chemical fixation may generate structural artifacts. Using live confocal microscope imaging we report here that cultured Aplysia neurons engulf protruding spine-shaped gold structures functionalized by an RGD-based peptide and to a significantly lesser extent by poly-l-lysine. The cytoskeletal elements actin and associated protein cortactin are shown to organize around the stalks of the engulfed gold spines in the form of rings. Neurons grown on the gold-spine matrix display varying growth patterns but maintain normal electrophysiological properties and form functioning synapses. It is concluded that the matrices of functionalized gold spines provide an improved substrate for the assembly of neuro-electronic hybrids.

  6. The significance of dynamical architecture for adaptive responses to mechanical loads during rhythmic behavior.

    Science.gov (United States)

    Shaw, Kendrick M; Lyttle, David N; Gill, Jeffrey P; Cullins, Miranda J; McManus, Jeffrey M; Lu, Hui; Thomas, Peter J; Chiel, Hillel J

    2015-02-01

    Many behaviors require reliably generating sequences of motor activity while adapting the activity to incoming sensory information. This process has often been conceptually explained as either fully dependent on sensory input (a chain reflex) or fully independent of sensory input (an idealized central pattern generator, or CPG), although the consensus of the field is that most neural pattern generators lie somewhere between these two extremes. Many mathematical models of neural pattern generators use limit cycles to generate the sequence of behaviors, but other models, such as a heteroclinic channel (an attracting chain of saddle points), have been suggested. To explore the range of intermediate behaviors between CPGs and chain reflexes, in this paper we describe a nominal model of swallowing in Aplysia californica. Depending upon the value of a single parameter, the model can transition from a generic limit cycle regime to a heteroclinic regime (where the trajectory slows as it passes near saddle points). We then study the behavior of the system in these two regimes and compare the behavior of the models with behavior recorded in the animal in vivo and in vitro. We show that while both pattern generators can generate similar behavior, the stable heteroclinic channel can better respond to changes in sensory input induced by load, and that the response matches the changes seen when a load is added in vivo. We then show that the underlying stable heteroclinic channel architecture exhibits dramatic slowing of activity when sensory and endogenous input is reduced, and show that similar slowing with removal of proprioception is seen in vitro. Finally, we show that the distributions of burst lengths seen in vivo are better matched by the distribution expected from a system operating in the heteroclinic regime than that expected from a generic limit cycle. These observations suggest that generic limit cycle models may fail to capture key aspects of Aplysia feeding

  7. Proximate composition of marine invertebrates from tropical coastal waters, with emphasis on the relationship between nitrogen and protein contents

    Directory of Open Access Journals (Sweden)

    Graciela S Diniz

    2014-05-01

    Full Text Available The chemical profiles of Desmapsamma anchorata, Hymeniacidon heliophila (Porifera, Bunodosoma caissarum, Renilla muelleri (Cnidaria, Aplysia brasiliana, Eledone massyae, Isognomon bicolor (Mollusca, Echinaster brasiliensis, Echinometra lucunter, Holothuria grisea, Lytechinus variegatus (Echinodermata, and Phallusia nigra (Chordata were determined. Hydrosoluble protein was the most abundant class of substances for all species, except for the ascidian Phallusia nigra, in which the carbohydrate content was higher. The percentages of hydrosoluble protein (dry weight, dw varied widely among the invertebrates, ranging from 5.88% (R. muelleri to 47.6% (Eledone massyae of the dw .The carbohydrate content fluctuated from 1.3% (R. muelleri to 18.4% (Aplysia brasiliana of the dw. For most of the species, lipid was the second most abundant class of substances, varying from 2.8% (R. muelleri to 25.3% (Echinaster brasiliensis of the dw. Wide variations were also found for the invertebrates nitrogen content, with the lowest value recorded in the cnidarian R. muelleri (2.02% of the dw and the highest in the molluscan E. massyae (12.7% of the dw. The phosphorus content of the dw varyed from 0.24% (R. muelleri to 1.16% (E. massyae. The amino acid composition varied largely among the species, but for most of the species glycine, arginine, glutamic acid, and aspartic acid were the most abundant amino acids, with histidine and tyrosine among the less abundant amino acids. The actual content of total protein in the samples was calculated by the sum of amino acid residues, establishing dw values that fluctuated from 11.1% (R. muelleri to 66.7% (E. massyae. The proteinaceous nitrogen content was high in all species, with an average value of 97.3% of the total nitrogen. From data of total amino acid residues and total nitrogen, specific nitrogen-to-protein conversion factors were calculated for each species. The nitrogen-to-protein conversion factors ranged from 5.10 to

  8. The rates of protein synthesis and degradation account for the differential response of neurons to spaced and massed training protocols.

    Directory of Open Access Journals (Sweden)

    Faisal Naqib

    2011-12-01

    Full Text Available The sensory-motor neuron synapse of Aplysia is an excellent model system for investigating the biochemical changes underlying memory formation. In this system, training that is separated by rest periods (spaced training leads to persistent changes in synaptic strength that depend on biochemical pathways that are different from those that occur when the training lacks rest periods (massed training. Recently, we have shown that in isolated sensory neurons, applications of serotonin, the neurotransmitter implicated in inducing these synaptic changes during memory formation, lead to desensitization of the PKC Apl II response, in a manner that depends on the method of application (spaced versus massed. Here, we develop a mathematical model of this response in order to gain insight into how neurons sense these different training protocols. The model was developed incrementally, and each component was experimentally validated, leading to two novel findings: First, the increased desensitization due to PKA-mediated heterologous desensitization is coupled to a faster recovery than the homologous desensitization that occurs in the absence of PKA activity. Second, the model suggests that increased spacing leads to greater desensitization due to the short half-life of a hypothetical protein, whose production prevents homologous desensitization. Thus, we predict that the effects of differential spacing are largely driven by the rates of production and degradation of proteins. This prediction suggests a powerful mechanism by which information about time is incorporated into neuronal processing.

  9. Molecular characterization and analysis of a putative 5-HT receptor involved in reproduction process of the pearl oyster Pinctada fucata.

    Science.gov (United States)

    Wang, Qi; He, Maoxian

    2014-08-01

    5-HT (5-hydroxytryptamine; serotonin) has been linked to a variety of biological roles including gonad maturation and sequential spawning in bivalve molluscs. To gain a better understanding of the effects of 5-HT on developmental regulation in the pearl oyster Pinctada fucata, the isolation, cloning, and expression of the 5-HT receptor was investigated in this study. A full-length cDNA (2541 bp) encoding a putative 5-HT receptor (5-HTpf) of 471 amino acids was isolated from the ovary of the pearl oyster. It shared 71% and 51% homology, respectively, with the Crassostrea gigas 5-HT receptor and the Aplysia californica 5-HT1ap. The 5-HTpf sequence possessed the typical characteristics of seven transmembrane domains and a long third inner loop. Phylogenetic analysis also indicated that 5-HTpf was classified into the 5-HT1 subtype together with other invertebrate 5-HT1 receptors. Quantitative RT-PCR showed that 5-HTpf is widely expressed in all tissues tested, is involved in the gametogenesis cycle, embryonic and larval development stages, and expression is induced by E2 in ovarian tissues. These results suggest that 5-HTpf is involved in the reproductive process, specifically in the induction of oocyte maturation and spawning of P. fucata. PMID:24852353

  10. Atomic interactions of neonicotinoid agonists with AChBP: Molecular recognition of the distinctive electronegative pharmacophore

    Energy Technology Data Exchange (ETDEWEB)

    Talley, Todd T.; Harel, Michal; Hibbs, Ryan E.; Radi, Zoran; Tomizawa, Motohiro; Casida, John E.; Taylor, Palmer (UCB); (UCSD)

    2008-07-28

    Acetylcholine-binding proteins (AChBPs) from mollusks are suitable structural and functional surrogates of the nicotinic acetylcholine receptors when combined with transmembrane spans of the nicotinic receptor. These proteins assemble as a pentamer with identical ACh binding sites at the subunit interfaces and show ligand specificities resembling those of the nicotinic receptor for agonists and antagonists. A subset of ligands, termed the neonicotinoids, exhibit specificity for insect nicotinic receptors and selective toxicity as insecticides. AChBPs are of neither mammalian nor insect origin and exhibit a distinctive pattern of selectivity for the neonicotinoid ligands. We define here the binding orientation and determinants of differential molecular recognition for the neonicotinoids and classical nicotinoids by estimates of kinetic and equilibrium binding parameters and crystallographic analysis. Neonicotinoid complex formation is rapid and accompanied by quenching of the AChBP tryptophan fluorescence. Comparisons of the neonicotinoids imidacloprid and thiacloprid in the binding site from Aplysia californica AChBP at 2.48 and 1.94 {angstrom} in resolution reveal a single conformation of the bound ligands with four of the five sites occupied in the pentameric crystal structure. The neonicotinoid electronegative pharmacophore is nestled in an inverted direction compared with the nicotinoid cationic functionality at the subunit interfacial binding pocket. Characteristic of several agonists, loop C largely envelops the ligand, positioning aromatic side chains to interact optimally with conjugated and hydrophobic regions of the neonicotinoid. This template defines the association of interacting amino acids and their energetic contributions to the distinctive interactions of neonicotinoids.

  11. Secondary Ion Mass Spectrometry Imaging of Molecular Distributions in Cultured Neurons and Their Processes: Comparative Analysis of Sample Preparation

    Science.gov (United States)

    Tucker, Kevin R.; Li, Zhen; Rubakhin, Stanislav S.; Sweedler, Jonathan V.

    2012-11-01

    Neurons often exhibit a complex chemical distribution and topography; therefore, sample preparation protocols that preserve structures ranging from relatively large cell somata to small neurites and growth cones are important factors in secondary ion mass spectrometry (SIMS) imaging studies. Here, SIMS was used to investigate the subcellular localization of lipids and lipophilic species in neurons from Aplysia californica. Using individual neurons cultured on silicon wafers, we compared and optimized several SIMS sampling approaches. After an initial step to remove the high salt culturing media, formaldehyde, paraformaldehyde, and glycerol, and various combinations thereof, were tested for their ability to achieve cell stabilization during and after the removal of extracellular media. These treatments improved the preservation of cellular morphology as visualized with SIMS imaging. For analytes >250 Da, coating the cell surface with a 3.2 nm-thick gold layer increased the ion intensity; multiple analytes previously not observed or observed at low abundance were detected, including intact cholesterol and vitamin E molecular ions. However, once a sample was coated, many of the lower molecular mass (cultured neurons over a broad mass range with enhanced image contrast.

  12. The CPEB3 Protein Is a Functional Prion that Interacts with the Actin Cytoskeleton

    Directory of Open Access Journals (Sweden)

    Joseph S. Stephan

    2015-06-01

    Full Text Available The mouse cytoplasmic polyadenylation element-binding protein 3 (CPEB3 is a translational regulator implicated in long-term memory maintenance. Invertebrate orthologs of CPEB3 in Aplysia and Drosophila are functional prions that are physiologically active in the aggregated state. To determine if this principle applies to the mammalian CPEB3, we expressed it in yeast and found that it forms heritable aggregates that are the hallmark of known prions. In addition, we confirm in the mouse the importance of CPEB3’s prion formation for CPEB3 function. Interestingly, deletion analysis of the CPEB3 prion domain uncovered a tripartite organization: two aggregation-promoting domains surround a regulatory module that affects interaction with the actin cytoskeleton. In all, our data provide direct evidence that CPEB3 is a functional prion in the mammalian brain and underline the potential importance of an actin/CPEB3 feedback loop for the synaptic plasticity underlying the persistence of long-term memory.

  13. Fast and slow activation kinetics of voltage-gated sodium channels in molluscan neurons.

    Science.gov (United States)

    Gilly, W F; Gillette, R; McFarlane, M

    1997-05-01

    Whole cell patch-clamp recordings of Na current (I(Na)) were made under identical experimental conditions from isolated neurons from cephalopod (Loligo, Octopus) and gastropod (Aplysia, Pleurobranchaea, Doriopsilla) species to compare properties of activation gating. Voltage dependence of peak Na conductance (gNa) is very similar in all cases, but activation kinetics in the gastropod neurons studied are markedly slower. Kinetic differences are very pronounced only over the voltage range spanned by the gNa-voltage relation. At positive and negative extremes of voltage, activation and deactivation kinetics of I(Na) are practically indistinguishable in all species studied. Voltage-dependent rate constants underlying activation of the slow type of Na channel found in gastropods thus appear to be much more voltage dependent than are the equivalent rates in the universally fast type of channel that predominates in cephalopods. Voltage dependence of inactivation kinetics shows a similar pattern and is representative of activation kinetics for the two types of Na channels. Neurons with fast Na channels can thus make much more rapid adjustments in the number of open Na channels at physiologically relevant voltages than would be possible with only slow Na channels. This capability appears to be an adaptation that is highly evolved in cephalopods, which are well known for their high-speed swimming behaviors. Similarities in slow and fast Na channel subtypes in molluscan and mammalian neurons are discussed. PMID:9163364

  14. Functional expression of soluble forms of human CD38 in Escherichia coli and Pichia pastoris.

    Science.gov (United States)

    Fryxell, K B; O'Donoghue, K; Graeff, R M; Lee, H C; Branton, W D

    1995-06-01

    Cyclic adenosine diphosphate (ADP)-ribose (cADPR), a metabolite of nicotinamide adenine dinucleotide (NAD+), mobilizes calcium from intracellular stores in many cells. The synthesis of cADPR from NAD+ and its subsequent hydrolysis to ADPR is catalyzed by an ADP-ribosyl cyclase and a cADPR hydrolase, respectively. The ADP-ribosyl cyclase cloned from the ovotestis of the marine invertebrate Aplysia californica has amino acid sequence homology to the human lymphocyte surface antigen CD38. CD38 has been shown to catalyze both the formation and the hydrolysis of cADPR. In this study, we produced soluble, enzymatically active CD38 using recombinant expression techniques in bacteria and yeast. We engineered a gene coding for a soluble form of CD38 by excision of the region of the gene coding for the N-terminal amino acids representing the putative membrane spanning sequence and short putative intracellular sequence. For expression in bacteria (Escherichia coli), this construct was cloned into the pFlag-1 plasmid which allows induced, periplasmic expression and relatively simple purification of the soluble CD38. For expression in yeast (Pichia pastoris) the CD38 sequence was further modified to eliminate four putative N-linked glycosylation sites and the resulting construct was expressed as a secreted protein. Both systems produce soluble enzymes of approximately 30 kDa and both recombinant enzymes display similar cyclase and hydrolase activities. PMID:7663169

  15. Lesions of Copper Toxicosis in Captive Marine Invertebrates With Comparisons to Normal Histology.

    Science.gov (United States)

    LaDouceur, E E B; Wynne, J; Garner, M M; Nyaoke, A; Keel, M K

    2016-05-01

    Despite increasing concern for coral reef ecosystem health within the last decade, there is scant literature concerning the histopathology of diseases affecting the major constituents of coral reef ecosystems, particularly marine invertebrates. This study describes histologic findings in 6 species of marine invertebrates (California sea hare [Aplysia californica], purple sea urchin [Strongylocentrotus purpuratus], sunburst anemone [Anthopleura sola], knobby star [Pisaster giganteus], bat star [Asterina miniata], and brittle star [Ophiopteris papillosa]) with spontaneous copper toxicosis, 4 purple sea urchins with experimentally induced copper toxicosis, and 1 unexposed control of each species listed. The primary lesions in the California sea hare with copper toxicosis were branchial and nephridial necrosis. Affected echinoderms shared several histologic lesions, including epidermal necrosis and ulceration and increased numbers of coelomocytes within the water-vascular system. The sunburst anemone with copper toxicosis had necrosis of both epidermis and gastrodermis, as well as expulsion of zooxanthellae from the gastrodermis. In addition to the lesions attributed to copper toxicosis, our results describe normal microscopic features of these animals that may be useful for histopathologic assessment of marine invertebrates. PMID:26459519

  16. In Vitro Studies of Neuronal Networks and Synaptic Plasticity in Invertebrates and in Mammals Using Multielectrode Arrays

    Directory of Open Access Journals (Sweden)

    Paolo Massobrio

    2015-01-01

    Full Text Available Brain functions are strictly dependent on neural connections formed during development and modified during life. The cellular and molecular mechanisms underlying synaptogenesis and plastic changes involved in learning and memory have been analyzed in detail in simple animals such as invertebrates and in circuits of mammalian brains mainly by intracellular recordings of neuronal activity. In the last decades, the evolution of techniques such as microelectrode arrays (MEAs that allow simultaneous, long-lasting, noninvasive, extracellular recordings from a large number of neurons has proven very useful to study long-term processes in neuronal networks in vivo and in vitro. In this work, we start off by briefly reviewing the microelectrode array technology and the optimization of the coupling between neurons and microtransducers to detect subthreshold synaptic signals. Then, we report MEA studies of circuit formation and activity in invertebrate models such as Lymnaea, Aplysia, and Helix. In the following sections, we analyze plasticity and connectivity in cultures of mammalian dissociated neurons, focusing on spontaneous activity and electrical stimulation. We conclude by discussing plasticity in closed-loop experiments.

  17. PKC in motorneurons underlies self-learning, a form of motor learning in Drosophila

    Science.gov (United States)

    Colomb, Julien

    2016-01-01

    Tethering a fly for stationary flight allows for exquisite control of its sensory input, such as visual or olfactory stimuli or a punishing infrared laser beam. A torque meter measures the turning attempts of the tethered fly around its vertical body axis. By punishing, say, left turning attempts (in a homogeneous environment), one can train a fly to restrict its behaviour to right turning attempts. It was recently discovered that this form of operant conditioning (called operant self-learning), may constitute a form of motor learning in Drosophila. Previous work had shown that Protein Kinase C (PKC) and the transcription factor dFoxP were specifically involved in self-learning, but not in other forms of learning. These molecules are specifically involved in various forms of motor learning in other animals, such as compulsive biting in Aplysia, song-learning in birds, procedural learning in mice or language acquisition in humans. Here we describe our efforts to decipher which PKC gene is involved in self-learning in Drosophila. We also provide evidence that motorneurons may be one part of the neuronal network modified during self-learning experiments. The collected evidence is reminiscent of one of the simplest, clinically relevant forms of motor learning in humans, operant reflex conditioning, which also relies on motorneuron plasticity.

  18. In Vitro Studies of Neuronal Networks and Synaptic Plasticity in Invertebrates and in Mammals Using Multielectrode Arrays

    Science.gov (United States)

    Tessadori, Jacopo; Ghirardi, Mirella

    2015-01-01

    Brain functions are strictly dependent on neural connections formed during development and modified during life. The cellular and molecular mechanisms underlying synaptogenesis and plastic changes involved in learning and memory have been analyzed in detail in simple animals such as invertebrates and in circuits of mammalian brains mainly by intracellular recordings of neuronal activity. In the last decades, the evolution of techniques such as microelectrode arrays (MEAs) that allow simultaneous, long-lasting, noninvasive, extracellular recordings from a large number of neurons has proven very useful to study long-term processes in neuronal networks in vivo and in vitro. In this work, we start off by briefly reviewing the microelectrode array technology and the optimization of the coupling between neurons and microtransducers to detect subthreshold synaptic signals. Then, we report MEA studies of circuit formation and activity in invertebrate models such as Lymnaea, Aplysia, and Helix. In the following sections, we analyze plasticity and connectivity in cultures of mammalian dissociated neurons, focusing on spontaneous activity and electrical stimulation. We conclude by discussing plasticity in closed-loop experiments. PMID:25866681

  19. Secondary Ion Mass Spectrometry Imaging of Molecular Distributions in Cultured Neurons and Their Processes: Comparative Analysis of Sample Preparation

    Science.gov (United States)

    Tucker, Kevin R.; Li, Zhen; Rubakhin, Stanislav S.; Sweedler, Jonathan V.

    2012-11-01

    Neurons often exhibit a complex chemical distribution and topography; therefore, sample preparation protocols that preserve structures ranging from relatively large cell somata to small neurites and growth cones are important factors in secondary ion mass spectrometry (SIMS) imaging studies. Here, SIMS was used to investigate the subcellular localization of lipids and lipophilic species in neurons from Aplysia californica. Using individual neurons cultured on silicon wafers, we compared and optimized several SIMS sampling approaches. After an initial step to remove the high salt culturing media, formaldehyde, paraformaldehyde, and glycerol, and various combinations thereof, were tested for their ability to achieve cell stabilization during and after the removal of extracellular media. These treatments improved the preservation of cellular morphology as visualized with SIMS imaging. For analytes >250 Da, coating the cell surface with a 3.2 nm-thick gold layer increased the ion intensity; multiple analytes previously not observed or observed at low abundance were detected, including intact cholesterol and vitamin E molecular ions. However, once a sample was coated, many of the lower molecular mass (stabilization with glycerol and 4 % paraformaldehyde. The sample preparation methods described here enhance SIMS imaging of processes of individual cultured neurons over a broad mass range with enhanced image contrast.

  20. Serotonin-like immunoreactivity in the central and peripheral nervous systems of the interstitial acochlidean Asperspina sp. (Opisthobranchia).

    Science.gov (United States)

    Hochberg, Rick

    2007-08-01

    Species of Acochlidea are common members of the marine interstitial environment and defined in part by their minuscule size and highly divergent morphology relative to other benthic opisthobranchs. Despite these differences, acochlideans such as species of Asperspina display many plesiomorphic characteristics, including an unfused condition of their neural ganglia. To gain insight into the distribution of specific neural subsets within acochlidean ganglia, a species of Asperspina was studied by using anti-serotonin immunohistochemistry and epifluorescence and confocal laser scanning microscopy. Results reveal similarities between Asperspina and larger opisthobranchs in the general distribution of serotonergic perikarya in the central nervous system. Specifically, the arrangement of perikarya into regional clusters within the cerebral and pedal ganglia and the absence of immunoreactive perikarya in the pleural ganglia are similar to the model species of Aplysia californica, Pleurobranchaea californica, and Tritonia diomedea. Moreover, serotonergic innervation of the rhinophores in all opisthobranchs, including Asperspina sp., originates from the cerebral ganglion instead of directly from the rhinophoral ganglion. Serotonergic innervation of the body wall, including the epithelium, muscles, and pedal sole, appears to arise exclusively from pedal and accessory ganglia. These observations indicate a general conservation of serotonin-like immunoreactivity in the central and peripheral nervous systems of acochlidean and other benthic opisthobranchs. PMID:17679719

  1. Functional neuroanatomy of the rhinophore of Archidoris pseudoargus

    Science.gov (United States)

    Wertz, Adrian; Rössler, Wolfgang; Obermayer, Malu; Bickmeyer, Ulf

    2007-06-01

    For sea slugs, chemosensory information represents an important sensory modality, because optical and acoustical information are limited. In the present study, we focussed on the neuroanatomy of the rhinophores and processing of olfactory stimuli in the rhinophore ganglion of Archidoris pseudoargus, belonging to the order of Nudibranchia in the subclass of Opisthobranchia. Histological techniques, fluorescent markers, and immunohistochemistry were used to analyse neuroanatomical features of the rhinophore. A large ganglion and a prominent central lymphatic channel are surrounded by longitudinal muscles. Many serotonin-immunoreactive (IR) processes were found around the centre and between the ganglion and the highly folded lobes of the rhinophore, but serotonin-IR cell bodies were absent inside the rhinophore. In contrast to the conditions recently found in Aplysia punctata, we found no evidence for the presence of olfactory glomeruli within the rhinophore. Using calcium-imaging techniques with Fura II as a calcium indicator, we found differential calcium responses in various regions within the ganglion to stimulation of the rhinophore with different amino acids. The lack of glomeruli in the rhinophores induces functional questions about processing of chemical information in the rhinophore.

  2. PKC in motorneurons underlies self-learning, a form of motor learning in Drosophila.

    Science.gov (United States)

    Colomb, Julien; Brembs, Björn

    2016-01-01

    Tethering a fly for stationary flight allows for exquisite control of its sensory input, such as visual or olfactory stimuli or a punishing infrared laser beam. A torque meter measures the turning attempts of the tethered fly around its vertical body axis. By punishing, say, left turning attempts (in a homogeneous environment), one can train a fly to restrict its behaviour to right turning attempts. It was recently discovered that this form of operant conditioning (called operant self-learning), may constitute a form of motor learning in Drosophila. Previous work had shown that Protein Kinase C (PKC) and the transcription factor dFoxP were specifically involved in self-learning, but not in other forms of learning. These molecules are specifically involved in various forms of motor learning in other animals, such as compulsive biting in Aplysia, song-learning in birds, procedural learning in mice or language acquisition in humans. Here we describe our efforts to decipher which PKC gene is involved in self-learning in Drosophila. We also provide evidence that motorneurons may be one part of the neuronal network modified during self-learning experiments. The collected evidence is reminiscent of one of the simplest, clinically relevant forms of motor learning in humans, operant reflex conditioning, which also relies on motorneuron plasticity. PMID:27168980

  3. New Invertebrate Vectors of Okadaic Acid from the North Atlantic Waters--Portugal (Azores and Madeira) and Morocco.

    Science.gov (United States)

    Silva, Marisa; Rodriguez, Inés; Barreiro, Aldo; Kaufmann, Manfred; Isabel Neto, Ana; Hassouani, Meryem; Sabour, Brahim; Alfonso, Amparo; Botana, Luis M; Vasconcelos, Vitor

    2015-12-01

    Okadaic acid and its analogues are potent phosphatase inhibitors that cause Diarrheic Shellfish Poisoning (DSP) through the ingestion of contaminated shellfish by humans. This group of toxins is transmitted worldwide but the number of poisoning incidents has declined over the last 20 years due to legislation and monitoring programs that were implemented for bivalves. In the summer of 2012 and 2013, we collected a total of 101 samples of 22 different species that were made up of benthic and subtidal organisms such echinoderms, crustaceans, bivalves and gastropods from Madeira, São Miguel Island (Azores archipelago) and the northwestern coast of Morocco. The samples were analyzed by UPLC-MS/MS. Our main objective was to detect new vectors for these biotoxins. We can report nine new vectors for these toxins in the North Atlantic: Astropecten aranciacus, Arbacia lixula, Echinaster sepositus, Holothuria sanctori, Ophidiaster ophidianus, Onchidella celtica, Aplysia depilans, Patella spp., and Stramonita haemostoma. Differences in toxin contents among the species were found. Even though low concentrations were detected, the levels of toxins that were present, especially in edible species, indicate the importance of these types of studies. Routine monitoring should be extended to comprise a wider number of vectors other than for bivalves of okadaic acid and its analogues. PMID:26670254

  4. New Invertebrate Vectors of Okadaic Acid from the North Atlantic Waters—Portugal (Azores and Madeira and Morocco

    Directory of Open Access Journals (Sweden)

    Marisa Silva

    2015-12-01

    Full Text Available Okadaic acid and its analogues are potent phosphatase inhibitors that cause Diarrheic Shellfish Poisoning (DSP through the ingestion of contaminated shellfish by humans. This group of toxins is transmitted worldwide but the number of poisoning incidents has declined over the last 20 years due to legislation and monitoring programs that were implemented for bivalves. In the summer of 2012 and 2013, we collected a total of 101 samples of 22 different species that were made up of benthic and subtidal organisms such echinoderms, crustaceans, bivalves and gastropods from Madeira, São Miguel Island (Azores archipelago and the northwestern coast of Morocco. The samples were analyzed by UPLC-MS/MS. Our main objective was to detect new vectors for these biotoxins. We can report nine new vectors for these toxins in the North Atlantic: Astropecten aranciacus, Arbacia lixula, Echinaster sepositus, Holothuria sanctori, Ophidiaster ophidianus, Onchidella celtica, Aplysia depilans, Patella spp., and Stramonita haemostoma. Differences in toxin contents among the species were found. Even though low concentrations were detected, the levels of toxins that were present, especially in edible species, indicate the importance of these types of studies. Routine monitoring should be extended to comprise a wider number of vectors other than for bivalves of okadaic acid and its analogues.

  5. Sea urchin coelomocytes are resistant to a variety of DNA damaging agents

    International Nuclear Information System (INIS)

    Increasing anthropogenic activities are creating environmental pressures that threaten marine ecosystems. Effective environmental health assessment requires the development of rapid, sensitive, and cost-effective tools to predict negative impacts at the individual and ecosystem levels. To this end, a number of biological assays using a variety of cells and organisms measuring different end points have been developed for biomonitoring programs. The sea urchin fertilization/development test has been useful for evaluating environmental toxicology and it has been proposed that sea urchin coelomocytes represent a novel cellular biosensor of environmental stress. In this study we investigated the sensitivity of coelomocytes from the sea urchin Lytechinus variegatus to a variety of DNA-damaging agents including ultraviolet (UV) radiation, hydrogen peroxide (H2O2), methylmethane sulfonate (MMS) and benzo[a]pyrene (BaP). LD50 values determined for coelomocytes after 24 h of exposure to these DNA damaging agents indicated a high level of resistance to all treatments. Significant increases in the formation of apurinic/apyrimidinic (AP or abasic) sites in DNA were only detected using high doses of H2O2, MMS and UV radiation. Comparison of sea urchin coelomocytes with hemocytes from the gastropod mollusk Aplysia dactylomela and the decapod crustacean Panulirus argus indicated that sensitivity to different DNA damaging agents varies between species. The high level of resistance to genotoxic agents suggests that DNA damage may not be an informative end point for environmental health assessment using sea urchin coelomocytes however, natural resistance to DNA damaging agents may have implications for the occurrence of neoplastic disease in these animals.

  6. Sea urchin coelomocytes are resistant to a variety of DNA damaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Loram, Jeannette; Raudonis, Renee; Chapman, Jecar; Lortie, Mae [Bermuda Institute of Ocean Sciences, St. George' s, Bermuda, GE 01 (Bermuda); Bodnar, Andrea, E-mail: andrea.bodnar@bios.edu [Bermuda Institute of Ocean Sciences, St. George' s, Bermuda, GE 01 (Bermuda)

    2012-11-15

    Increasing anthropogenic activities are creating environmental pressures that threaten marine ecosystems. Effective environmental health assessment requires the development of rapid, sensitive, and cost-effective tools to predict negative impacts at the individual and ecosystem levels. To this end, a number of biological assays using a variety of cells and organisms measuring different end points have been developed for biomonitoring programs. The sea urchin fertilization/development test has been useful for evaluating environmental toxicology and it has been proposed that sea urchin coelomocytes represent a novel cellular biosensor of environmental stress. In this study we investigated the sensitivity of coelomocytes from the sea urchin Lytechinus variegatus to a variety of DNA-damaging agents including ultraviolet (UV) radiation, hydrogen peroxide (H{sub 2}O{sub 2}), methylmethane sulfonate (MMS) and benzo[a]pyrene (BaP). LD{sub 50} values determined for coelomocytes after 24 h of exposure to these DNA damaging agents indicated a high level of resistance to all treatments. Significant increases in the formation of apurinic/apyrimidinic (AP or abasic) sites in DNA were only detected using high doses of H{sub 2}O{sub 2}, MMS and UV radiation. Comparison of sea urchin coelomocytes with hemocytes from the gastropod mollusk Aplysia dactylomela and the decapod crustacean Panulirus argus indicated that sensitivity to different DNA damaging agents varies between species. The high level of resistance to genotoxic agents suggests that DNA damage may not be an informative end point for environmental health assessment using sea urchin coelomocytes however, natural resistance to DNA damaging agents may have implications for the occurrence of neoplastic disease in these animals.

  7. Spike-adding in parabolic bursters: The role of folded-saddle canards

    Science.gov (United States)

    Desroches, Mathieu; Krupa, Martin; Rodrigues, Serafim

    2016-09-01

    The present work develops a new approach to studying parabolic bursting, and also proposes a novel four-dimensional canonical and polynomial-based parabolic burster. In addition to this new polynomial system, we also consider the conductance-based model of the Aplysia R15 neuron known as the Plant model, and a reduction of this prototypical biophysical parabolic burster to three variables, including one phase variable, namely the Baer-Rinzel-Carillo (BRC) phase model. Revisiting these models from the perspective of slow-fast dynamics reveals that the number of spikes per burst may vary upon parameter changes, however the spike-adding process occurs in an explosive fashion that involves special solutions called canards. This spike-adding canard explosion phenomenon is analysed by using tools from geometric singular perturbation theory in tandem with numerical bifurcation techniques. We find that the bifurcation structure persists across all considered systems, that is, spikes within the burst are incremented via the crossing of an excitability threshold given by a particular type of canard orbit, namely the true canard of a folded-saddle singularity. However there can be a difference in the spike-adding transitions in parameter space from one case to another, according to whether the process is continuous or discontinuous, which depends upon the geometry of the folded-saddle canard. Using these findings, we construct a new polynomial approximation of the Plant model, which retains all the key elements for parabolic bursting, including the spike-adding transitions mediated by folded-saddle canards. Finally, we briefly investigate the presence of spike-adding via canards in planar phase models of parabolic bursting, namely the theta model by Ermentrout and Kopell.

  8. New Mediterranean Biodiversity Records (October, 2014

    Directory of Open Access Journals (Sweden)

    S. KATSANEVAKIS

    2014-09-01

    Full Text Available The Collective Article ‘New Mediterranean Biodiversity Records’ of the Mediterranean Marine Science journal offers the means to publish biodiversity records in the Mediterranean Sea. The current article is divided in two parts, for records of alien and native species respectively. The new records of alien species include: the red alga Asparagopsis taxiformis (Crete and Lakonicos Gulf (Greece; the red alga Grateloupia turuturu (along the Israeli Mediterranean shore; the mantis shrimp Clorida albolitura (Gulf of Antalya, Turkey; the mud crab Dyspanopeus sayi (Mar Piccolo of Taranto, Ionian Sea; the blue crab Callinectes sapidus (Chios Island, Greece; the isopod Paracerceis sculpta (northern Aegean Sea, Greece; the sea urchin Diadema setosum (Gökova Bay, Turkey; the molluscs Smaragdia souverbiana, Murex forskoehlii, Fusinus verrucosus, Circenita callipyga, and Aplysia dactylomela (Syria; the cephalaspidean mollusc Haminoea cyanomarginata (Baia di Puolo, Massa Lubrense, Campania, southern Italy; the topmouth gudgeon Pseudorasbora parva (Civitavecchia, Tyrrhenian Sea; the fangtooth moray Enchelycore anatine (Plemmirio marine reserve, Sicily; the silver-cheeked toadfish Lagocephalus sceleratus (Saros Bay, Turkey; and Ibiza channel, Spain; the Indo-Pacific ascidian Herdmania momusin Kastelorizo Island (Greece; and the foraminiferal Clavulina multicam erata (Saronikos Gulf, Greece. The record of L. sceleratus in Spain consists the deepest (350-400m depth record of the species in the Mediterranean Sea. The new records of native species include: first record of the ctenophore Cestum veneris in Turkish marine waters; the presence of Holothuria tubulosa and Holothuria polii in the Bay of Igoumenitsa (Greece; the first recorded sighting of the bull ray Pteromylaeus bovinus in Maltese waters; and a new record of the fish Lobotes surinamensis from Maliakos Gulf. 

  9. Radiochemical assay for ACh: modifications for sub-picomole measurements

    International Nuclear Information System (INIS)

    Details are given of modifications which have been made to a radiochemical technique for the determination of picomole levels of ACH (Goldberg, A., and McCaman, R., 1973, J. Neurochem., vol. 20, 1; Goldberg, A., and McCaman, R., 1974, in Choline and Acetylcholine: Handbook of Chemical Assay Methods, ed. Hanin, I., Raven Press, New York). The procedure involved the conversion of ACh to choline-32PO4 in the presence of AT32P and the enzymes, acetylcholinesterase and choline kinase. A substantial increase in sensitivity (from 2.5 to 0.04 pmol) has been achieved by increasing the specific activity of the [γ-32P]ATP and decreasing the reagent blank. The number of manipulative steps has been reduced. The ion exchange columns, prepared in Pasteur pipettes, could be reused indefinitely. Assays could be carried out with 8 to 500 μg wet weight of tissue. Values for ACh determined by the technique were proportional to tissue over a 500-fold range, from approximately 0.1 to 50 μg protein. The increased sensitivity was demonstrated by comparison of the results for the ACh content of individual soma determined by both procedures. The modified assay procedure gave 125,000 cpm in an assay for ACh in single Aplysia neurons, showing that considerably smaller cells than these could be assayed for ACh. Only a fraction of the cell extract is needed to obtain reliable measurements, and the remainder of the extract can then be used in other assays. (U.K.)

  10. [Nobel prize in physiology of medicine for year 2000 for research of signal transduction in the nervous system].

    Science.gov (United States)

    Gispen, W H

    2000-11-11

    The three Nobel laureates Arvid Carlsson, Paul Greengard and Eric Kandel have made pioneering discoveries concerning slow synaptic transmission between neurons. As common theme, for which the Nobel Prize in Physiology or Medicine for 2000 is given, the Nobel Assembly chose 'signal transduction in the nervous system'. The work of Carlsson led to the discovery of dopamine as transmitter in the brain and opened the way for the development of the levodopa therapy of patients suffering from Parkinson's disease. His later work concentrated on the dopamine hypothesis of schizophrenia and the rationale for the mechanism of action of antipsychotics. Greengard pioneered the field of receptor-mediated phosphorylation and dephosphorylation of brain proteins. He was the first to describe the cyclic-AMP-dependent protein kinase in the brain and the activation of this kinase following dopamine receptor activation. A substrate enriched in cells that bear dopamine receptors is 'dopamine- and cyclic-AMP-regulated phosphoprotein' (DARPP-32). Phosphorylation by the cyclic-AMP-dependent kinase influences its protein phosphatase inhibiting capacity and, as such, DARPP-32 is an important 'feed-forward activator' in the dopamine signal transduction cascade. Kandel received the prize for his contributions to our understanding of the neural substrate of learning and memory. Most of his work was carried out in the sea slug Aplysia in which he was able to relate three psychologically defined forms of learning--habituation, sensitisation, and classical conditioning--to subcellular processes and intercellular signalling. Kandel is known all over the world for his eminent textbook Principles of Neural Science which inspired generations of young neuroscientists. It seems that it is not so much the signal transduction that joins these laureates but their outstanding conceptual approach to, in fact, three different themes of the neurosciences during the second part of the last century. PMID

  11. Interview with eric R. Kandel: from memory, free will, and the problem with Freud to fortunate decisions.

    Science.gov (United States)

    Kandel, Eric R

    2008-01-01

    Eric R. Kandel shared the Nobel Prize for Physiology or Medicine with Arvid Carlsson and Paul Greengard in 2000 for their discoveries concerning signal transduction in the nervous system. Eric Kandel was rewarded for his discoveries of molecular mechanisms underlying learning and memory. He is a Howard Hughes Medical Institute Senior Investigator at Columbia Universities Center for Neurobiology and Behavior. In this interview given at Hertie Foundation's Neuroforum 2008 on April 18, 2008 in Frankfurt, Germany, Nobel Prize Laureate Eric R. Kandel takes us on an enlighting journey ranging from memory, free will, the problem with Freud , to scientific challenges and the rise of European science. Starting with short- and long-term memory basics, underlying molecular mechanisms, and events affecting the formation of long-term memory, Eric Kandel then shares his thoughts on the issue of free will and makes a strong case for its existence. In addition to his outstanding scientific career, Eric Kandel developed an interest in business and today serves as scientific advisor at Memory Pharmaceuticals. Eric Kandel then talks about the use and abuse of drugs in children and the merging of scientific disciplines. In one of the most intriguing parts of the interview, Kandel shares his thoughts on Freud, Freud's mistakes, and the unique situation that the generations following Freud did not develop Freud's work further. The interview then turns to more scientific aspects and Eric Kandel talks about his confidence and courage during the initial phases of his scientific career, studying learning and memory, and employing a strictly reductionistic approach, best characterized by his simple model organism Aplysia. Eric Kandel then describes one of the most challenging phases in his scientific career when adult neurogenesis was discovered in the hippocampus, a structure so integral to Kandel's work. The final parts of the interview cover today's absence of epic battles and

  12. From Polyplacophora to Cephalopoda: comparative analysis of nitric oxide signalling in mollusca.

    Science.gov (United States)

    Moroz, L L; Gillette, R

    1995-01-01

    The distribution of putative nitric oxide synthase (NOS)-containing cells has been analysed using NADPH-d histochemistry in the CNS and peripheral tissues in more than 2D ecologically and systematically different molluscan genera representing 3 main classes of the phylum MOLLUSCA: Polyplacophora (Lepidopleurus, Lepidozona, Katharina), Gastropoda (Littorina, Lymnaea, Aplexa, Physa, Planorbarius, Planorbis, Helisoma, Biomphalaria, Helix, Limax, Cepaea, Bulla, Aplysia, Phyllaplysia, Philine, Pleurobranchea, Tritonia, Armina, Flabellina, Cadlina) and Cephalopoda (Octopus, Sepia, Rossia, Loligo). Several species were used for more detailed immunohistochemical, biochemical, biophysical and physiological studies to further assay of NOS activity and to analyse functional roles of nitric oxide (NO) in these animals. The main conclusions of our comparative analysis and literature survey can be summarised as following: (i) There is strong evidence for the presence of NO-dependent signalling pathways in different molluscan species. (ii) We hypothesise that a general tendency in the evolution of NADPH-d-reactive cells in Mollusca is a migration of nitrergic function from periphery to the CNS. Also, different isoforms of NOS appear to be present in any one species. (iii) One of the main functional targets of NO signalling is the feeding system. However, there are obvious differences between predators (many labelled central motoneurons) and herbivorous species (many labelled peripheral putative sensory cells) as well as between land/freshwater and marine animals. Nevertheless, in all species tested NO-activated feeding-like motor patterns in the buccal ganglia. Additional functional and cellular targets for NO in molluscs are also considered. We briefly review neuromodulatory mechanisms of NO action and we consider molluscs as useful model systems for investigations of the roles of NO. PMID:8853687

  13. Computational exploration of a protein receptor binding space with student proposed peptide ligands.

    Science.gov (United States)

    King, Matthew D; Phillips, Paul; Turner, Matthew W; Katz, Michael; Lew, Sarah; Bradburn, Sarah; Andersen, Tim; McDougal, Owen M

    2016-01-01

    Computational molecular docking is a fast and effective in silico method for the analysis of binding between a protein receptor model and a ligand. The visualization and manipulation of protein to ligand binding in three-dimensional space represents a powerful tool in the biochemistry curriculum to enhance student learning. The DockoMatic tutorial described herein provides a framework by which instructors can guide students through a drug screening exercise. Using receptor models derived from readily available protein crystal structures, docking programs have the ability to predict ligand binding properties, such as preferential binding orientations and binding affinities. The use of computational studies can significantly enhance complimentary wet chemical experimentation by providing insight into the important molecular interactions within the system of interest, as well as guide the design of new candidate ligands based on observed binding motifs and energetics. In this laboratory tutorial, the graphical user interface, DockoMatic, facilitates docking job submissions to the docking engine, AutoDock 4.2. The purpose of this exercise is to successfully dock a 17-amino acid peptide, α-conotoxin TxIA, to the acetylcholine binding protein from Aplysia californica-AChBP to determine the most stable binding configuration. Each student will then propose two specific amino acid substitutions of α-conotoxin TxIA to enhance peptide binding affinity, create the mutant in DockoMatic, and perform docking calculations to compare their results with the class. Students will also compare intermolecular forces, binding energy, and geometric orientation of their prepared analog to their initial α-conotoxin TxIA docking results. PMID:26537635

  14. Deep mRNA sequencing of the Tritonia diomedea brain transcriptome provides access to gene homologues for neuronal excitability, synaptic transmission and peptidergic signalling.

    Directory of Open Access Journals (Sweden)

    Adriano Senatore

    Full Text Available The sea slug Tritonia diomedea (Mollusca, Gastropoda, Nudibranchia, has a simple and highly accessible nervous system, making it useful for studying neuronal and synaptic mechanisms underlying behavior. Although many important contributions have been made using Tritonia, until now, a lack of genetic information has impeded exploration at the molecular level.We performed Illumina sequencing of central nervous system mRNAs from Tritonia, generating 133.1 million 100 base pair, paired-end reads. De novo reconstruction of the RNA-Seq data yielded a total of 185,546 contigs, which partitioned into 123,154 non-redundant gene clusters (unigenes. BLAST comparison with RefSeq and Swiss-Prot protein databases, as well as mRNA data from other invertebrates (gastropod molluscs: Aplysia californica, Lymnaea stagnalis and Biomphalaria glabrata; cnidarian: Nematostella vectensis revealed that up to 76,292 unigenes in the Tritonia transcriptome have putative homologues in other databases, 18,246 of which are below a more stringent E-value cut-off of 1x10-6. In silico prediction of secreted proteins from the Tritonia transcriptome shotgun assembly (TSA produced a database of 579 unique sequences of secreted proteins, which also exhibited markedly higher expression levels compared to other genes in the TSA.Our efforts greatly expand the availability of gene sequences available for Tritonia diomedea. We were able to extract full length protein sequences for most queried genes, including those involved in electrical excitability, synaptic vesicle release and neurotransmission, thus confirming that the transcriptome will serve as a useful tool for probing the molecular correlates of behavior in this species. We also generated a neurosecretome database that will serve as a useful tool for probing peptidergic signalling systems in the Tritonia brain.

  15. Distribution and evolution of the serine/aspartate racemase family in invertebrates.

    Science.gov (United States)

    Uda, Kouji; Abe, Keita; Dehara, Yoko; Mizobata, Kiriko; Sogawa, Natsumi; Akagi, Yuki; Saigan, Mai; Radkov, Atanas D; Moe, Luke A

    2016-02-01

    Free D-amino acids have been found in various invertebrate phyla, while amino acid racemase genes have been identified in few species. The purpose of this study is to elucidate the distribution, function, and evolution of amino acid racemases in invertebrate animals. We searched the GenBank databases, and found 11 homologous serine racemase genes from eight species in eight different invertebrate phyla. The cloned genes were identified based on their maximum activity as Acropora millepora (Cnidaria) serine racemase (SerR) and aspartate racemase (AspR), Caenorhabditis elegans (Nematoda) SerR, Capitella teleta (Annelida) SerR, Crassostrea gigas (Mollusca) SerR and AspR, Dugesia japonica (Platyhelminthes) SerR, Milnesium tardigradum (Tardigrada) SerR, Penaeus monodon (Arthropoda) SerR and AspR and Strongylocentrotus purpuratus (Echinodermata) AspR. We found that Acropora, Aplysia, Capitella, Crassostrea and Penaeus had two amino acid racemase paralogous genes and these paralogous genes have evolved independently by gene duplication at their recent ancestral species. The transcriptome analyses using available SRA data and enzyme kinetic data suggested that these paralogous genes are expressed in different tissues and have different functions in vivo. Phylogenetic analyses clearly indicated that animal SerR and AspR are not separated by their particular racemase functions and form a serine/aspartate racemase family cluster. Our results revealed that SerR and AspR are more widely distributed among invertebrates than previously known. Moreover, we propose that the triple serine loop motif at amino acid positions 150-152 may be responsible for the large aspartate racemase activity and the AspR evolution from SerR. PMID:26352274

  16. Vibrational dynamics of thiocyanate and selenocyanate bound to horse heart myoglobin

    Science.gov (United States)

    Maj, Michał; Oh, Younjun; Park, Kwanghee; Lee, Jooyong; Kwak, Kyung-Won; Cho, Minhaeng

    2014-06-01

    The structure and vibrational dynamics of SCN- and SeCN-bound myoglobin have been investigated using polarization-controlled IR pump-probe measurements and quantum chemistry calculations. The complexes are found to be in low and high spin states, with the dominant contribution from the latter. In addition, the Mb:SCN high spin complex exhibits a doublet feature in the thiocyanate stretch IR absorption spectra, indicating two distinct molecular conformations around the heme pocket. The binding mode of the high spin complexes was assigned to occur through the nitrogen atom, contrary to the binding through the sulfur atom that was observed in myoglobin derived from Aplysia Limacina. The vibrational energy relaxation process has been found to occur substantially faster than those of free SCN- and SeCN- ions and neutral SCN- and SeCN-derivatized molecules reported previously. This supports the N-bound configurations of MbNCS and MbNCSe, because S- and Se-bound configurations are expected to have significantly long lifetimes due to the insulation effect by heavy bridge atom like S and Se in such IR probes. Nonetheless, even though their lifetimes are much shorter than those of corresponding free ions in water, the vibrational lifetimes determined for MbNCS and MbNCSe are still fairly long compared to those of azide and cyanide myoglobin systems studied before. Thus, thiocyanate and selenocyanate can be good local probes of local electrostatic environment in the heme pocket. The globin dependence on binding mode and vibrational dynamics is also discussed.

  17. Neuromolecular Imaging Shows Temporal Synchrony Patterns between Serotonin and Movement within Neuronal Motor Circuits in the Brain

    Directory of Open Access Journals (Sweden)

    Patricia A. Broderick

    2013-06-01

    Full Text Available The present discourse links the electrical and chemical properties of the brain with neurotransmitters and movement behaviors to further elucidate strategies to diagnose and treat brain disease. Neuromolecular imaging (NMI, based on electrochemical principles, is used to detect serotonin in nerve terminals (dorsal and ventral striata and somatodendrites (ventral tegmentum of reward/motor mesocorticolimbic and nigrostriatal brain circuits. Neuronal release of serotonin is detected at the same time and in the same animal, freely moving and unrestrained, while open-field behaviors are monitored via infrared photobeams. The purpose is to emphasize the unique ability of NMI and the BRODERICK PROBE® biosensors to empirically image a pattern of temporal synchrony, previously reported, for example, in Aplysia using central pattern generators (CPGs, serotonin and cerebral peptide-2. Temporal synchrony is reviewed within the context of the literature on central pattern generators, neurotransmitters and movement disorders. Specifically, temporal synchrony data are derived from studies on psychostimulant behavior with and without cocaine while at the same time and continuously, serotonin release in motor neurons within basal ganglia, is detected. The results show that temporal synchrony between the neurotransmitter, serotonin and natural movement occurs when the brain is NOT injured via, e.g., trauma, addictive drugs or psychiatric illness. In striking contrast, in the case of serotonin and cocaine-induced psychostimulant behavior, a different form of synchrony and also asynchrony can occur. Thus, the known dysfunctional movement behavior produced by cocaine may well be related to the loss of temporal synchrony, the loss of the ability to match serotonin in brain with motor activity. The empirical study of temporal synchrony patterns in humans and animals may be more relevant to the dynamics of motor circuits and movement behaviors than are studies of

  18. New Mediterranean Biodiversity Records (December 2012

    Directory of Open Access Journals (Sweden)

    M. THESSALOU-LEGAKI

    2013-01-01

    Full Text Available This paper presents records extending or confirming the distribution of Mediterranean species. Three alien algae are included, namely Codium taylorii reported for the first time from the Aegean and Turkey (Izmir Gulf, Caulerpa racemosa var. cylindracea (Karpathos and Chalki Isl., Aegean Sea and Ganonema farinosum (Karpathos Isl., Aegean Sea. As far as animals are concerned, Litarachna divergens (Acari: Hydrachnidia was recorded (Side, Eastern Mediterranean and represents a new amendment at genus level for Turkish fauna. Other invertebrates include alien species such as the crabs Dyspanopeus sayi (Lago Fusaro, SW Italy, Percnon gibbesi (Larnaca, Cyprus; Karpathos and Chalki Isl., Aegean Sea and Callinectes sapidus (Voda estuary, NW Greece, the nudibranch Aplysia dactylomela (Boka Kotorska Bay, Montenegro, the gastropod Conomurex persicus (Karpathos and ChalkiIsl., Aegean Sea and the bryozoan Electra tenella (Livorno harbour and Messina Straits area. The alien fish Siganus luridus, Siganus rivulatus, Fistularia commersonii, Sphyraena chrysotaenia and Sargocentron rubrum are also reported from the islands of Karpathos and Chalki, and Pteragogus pelycus from Heraklion Bay, Crete. In addition, new localities for four rare Mediterranean inhabitants are given: the cephalopod Thysanoteuthis rhombus (NW Sardinia and the fish: Lampris guttatus (Calabria, S Italy, Petromyzon marinus (Gokova Bay and Remora australis (Saronikos Gulf, while the opisthobranch gastropod Cerberilla bernadettae is reported for the first time from the E Mediterranean (Cyprus. Finally, three species of the Aegean ascidiofauna are recorded for the first time: Lissoclinum perforatum, Ciona roulei and Ecteinascidia turbinata. Furthermore, it was established that Phallusia nigra has extended its distributional range to the north of the Aegean Sea.

  19. Bioactive molecules from sea hares.

    Science.gov (United States)

    Kamiya, H; Sakai, R; Jimbo, M

    2006-01-01

    Sea hares, belonging to the order Opisthobranchia, subclass Gastropoda, are mollusks that have attracted many researchers who are interested in the chemical defense mechanisms of these soft and "shell-less" snails. Numbers of small molecules of dietary origin have been isolated from sea hares and some have ecologically relevant activities, such as fish deterrent activity or toxicity. Recently, however, greater attention has been paid to biomedically interesting sea hare isolates such as dolastatins, a series of antitumor peptide/macrolides isolated from Dolabella auricularia. Another series of bioactive peptide/macrolides, as represented by aplyronines, have been isolated from sea hares in Japanese waters. Although earlier studies indicated the potent antitumor activity of aplyronines, their clinical development has never been conducted because of the minute amount of compound available from the natural source. Recent synthetic studies, however, have made it possible to prepare these compounds and analogs for a structure-activity relationship study, and started to uncover their unique action mechanism towards their putative targets, microfilaments. Here, recent findings of small antitumor molecules isolated from Japanese sea hares are reviewed. Sea hares are also known to produce cytotoxic and antimicrobial proteins. In contrast to the small molecules of dietary origin, proteins are the genetic products of sea hares and they are likely to have some primary physiological functions in addition to ecological roles in the sea hare. Based on the biochemical properties and phylogenetic analysis of these proteins, we propose that they belong to one family of molecule, the "Aplysianin A family," although their molecular weights are apparently divided into two groups. Interestingly, the active principles in Aplysia species and Dolabella auricularia were shown to be L-amino acid oxidase (LAAO), a flavin enzyme that oxidizes an alpha-amino group of the substrate with

  20. Vibrational dynamics of thiocyanate and selenocyanate bound to horse heart myoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Maj, Michał; Oh, Younjun; Park, Kwanghee; Lee, Jooyong; Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of); Kwak, Kyung-Won [Department of Chemistry, Chung-Ang University, Seoul 156-756, SouthKorea (Korea, Republic of)

    2014-06-21

    The structure and vibrational dynamics of SCN- and SeCN-bound myoglobin have been investigated using polarization-controlled IR pump-probe measurements and quantum chemistry calculations. The complexes are found to be in low and high spin states, with the dominant contribution from the latter. In addition, the Mb:SCN high spin complex exhibits a doublet feature in the thiocyanate stretch IR absorption spectra, indicating two distinct molecular conformations around the heme pocket. The binding mode of the high spin complexes was assigned to occur through the nitrogen atom, contrary to the binding through the sulfur atom that was observed in myoglobin derived from Aplysia Limacina. The vibrational energy relaxation process has been found to occur substantially faster than those of free SCN{sup −} and SeCN{sup −} ions and neutral SCN- and SeCN-derivatized molecules reported previously. This supports the N-bound configurations of MbNCS and MbNCSe, because S- and Se-bound configurations are expected to have significantly long lifetimes due to the insulation effect by heavy bridge atom like S and Se in such IR probes. Nonetheless, even though their lifetimes are much shorter than those of corresponding free ions in water, the vibrational lifetimes determined for MbNCS and MbNCSe are still fairly long compared to those of azide and cyanide myoglobin systems studied before. Thus, thiocyanate and selenocyanate can be good local probes of local electrostatic environment in the heme pocket. The globin dependence on binding mode and vibrational dynamics is also discussed.

  1. Physiological, Molecular and Genetic Mechanisms of Long-Term Habituation

    Energy Technology Data Exchange (ETDEWEB)

    Calin-Jageman, Robert J

    2009-09-12

    Work funded on this grant has explored the mechanisms of long-term habituation, a ubiquitous form of learning that plays a key role in basic cognitive functioning. Specifically, behavioral, physiological, and molecular mechanisms of habituation have been explored using a simple model system, the tail-elicited siphon-withdrawal reflex (T-SWR) in the marine mollusk Aplysia californica. Substantial progress has been made on the first and third aims, providing some fundamental insights into the mechanisms by which memories are stored. We have characterized the physiological correlates of short- and long-term habituation. We found that short-term habituation is accompanied by a robust sensory adaptation, whereas long-term habituation is accompanied by alterations in sensory and interneuron synaptic efficacy. Thus, our data indicates memories can be shifted between different sites in a neural network as they are consolidated from short to long term. At the molecular level, we have accomplished microarray analysis comparing gene expression in both habituated and control ganglia. We have identified a network of putatively regulated transcripts that seems particularly targeted towards synaptic changes (e.g. SNAP25, calmodulin) . We are now beginning additional work to confirm regulation of these transcripts and build a more detailed understanding of the cascade of molecular events leading to the permanent storage of long-term memories. On the third aim, we have fostered a nascent neuroscience program via a variety of successful initiatives. We have funded over 11 undergraduate neuroscience scholars, several of whom have been recognized at national and regional levels for their research. We have also conducted a pioneering summer research program for community college students which is helping enhance access of underrepresented groups to life science careers. Despite minimal progress on the second aim, this project has provided a) novel insight into the network mechanisms by

  2. Comparative Analysis and Distribution of Omega-3 lcPUFA Biosynthesis Genes in Marine Molluscs

    Science.gov (United States)

    Surm, Joachim M.; Prentis, Peter J.; Pavasovic, Ana

    2015-01-01

    Recent research has identified marine molluscs as an excellent source of omega-3 long-chain polyunsaturated fatty acids (lcPUFAs), based on their potential for endogenous synthesis of lcPUFAs. In this study we generated a representative list of fatty acyl desaturase (Fad) and elongation of very long-chain fatty acid (Elovl) genes from major orders of Phylum Mollusca, through the interrogation of transcriptome and genome sequences, and various publicly available databases. We have identified novel and uncharacterised Fad and Elovl sequences in the following species: Anadara trapezia, Nerita albicilla, Nerita melanotragus, Crassostrea gigas, Lottia gigantea, Aplysia californica, Loligo pealeii and Chlamys farreri. Based on alignments of translated protein sequences of Fad and Elovl genes, the haeme binding motif and histidine boxes of Fad proteins, and the histidine box and seventeen important amino acids in Elovl proteins, were highly conserved. Phylogenetic analysis of aligned reference sequences was used to reconstruct the evolutionary relationships for Fad and Elovl genes separately. Multiple, well resolved clades for both the Fad and Elovl sequences were observed, suggesting that repeated rounds of gene duplication best explain the distribution of Fad and Elovl proteins across the major orders of molluscs. For Elovl sequences, one clade contained the functionally characterised Elovl5 proteins, while another clade contained proteins hypothesised to have Elovl4 function. Additional well resolved clades consisted only of uncharacterised Elovl sequences. One clade from the Fad phylogeny contained only uncharacterised proteins, while the other clade contained functionally characterised delta-5 desaturase proteins. The discovery of an uncharacterised Fad clade is particularly interesting as these divergent proteins may have novel functions. Overall, this paper presents a number of novel Fad and Elovl genes suggesting that many mollusc groups possess most of the

  3. [Memory: clinico-pathologic data].

    Science.gov (United States)

    Duyckaerts, C; Suarez, S; Hauw, J J

    1998-01-01

    Synaptic modifications are probably the basis of the memory processes that take place in the central nervous system. They have been studied in Aplysia or in hippocampal slices. How these minute alterations of the synaptic strength are integrated in larger neural systems is still poorly understood. In man, hippocampal lesions, when bilateral, cause a deficit in anterograde episodic memory. The loss of previously acquired memories (retrograde amnesia) is limited. Procedural memory is spared. Young patients with hippocampal lesions remain able to learn how to read or to write (abilities that belong to semantic memories). Recordings obtained with intracerebral electrodes have shown that some neurons of the hippocampus act as "place cells". They fire when the animal is in a specific place of the experimental maze, an observation that suggests that the hippocampus acts as a map that may also be viewed as a context indicator (a "cognitive map"). Computer models have been devised to test the hypothesis that the hippocampus recorded the map of the activated synapses at a particular moment in time. This pattern of activity could secondarily be transferred to the isocortex during a process known as consolidation. The frontal lobe plays a role in attention, which greatly influences the memory process. It also plays a role in the various strategies that are used to recall a memory and in the analysis of the quality of the recall (metamemory). An asymmetry has been shown by the PET-scan: the left frontal lobe is activated during acquisition, and the right one during recall. The ability to integrate one's own memories in one's own history and consciousness (self-awareness or "autonoesis") also depends on the activity of the prefrontal region. The loss of acquired memories (retrograde amnesia) is most often observed in cases of large lesions of the anterior part of the temporal lobe. Partial amnesias are difficult to separate from possibly localized deficits of a cognitive

  4. A critical period for gravitational effects on otolith formation

    Science.gov (United States)

    Wiederhold, M.; Harrison, J.

    Gravity and linear acceleration are sensed in fish by the saccule, utricle (as in mammals) and lagena, each with a solid otolith. Previous experiments in which eggs or larvae of a marine mollusk ( plysia) or fish larvae were raised on aA centrifuge, demonstrated that the size of the otolith or statoconia (in Aplysia) were reduced, in a graded manner, as the gfield was increased, suggesting that some- control mechanism was acting to normalize the weight of the mass. Pre-mated adult female swordtail fish (Xiphophorus helleri) were flown in the CEBAS aquarium system on space shuttle missions STS 89 and STS-90 (Neurolab). Developing- larvae were removed from the adult ovaries after shuttle landing. Otolith sizes were compared between ground- and flight -reared larvae of similar sizes. For later-stage swordtail larvae, with spine lengths from 3 to 6 mm from STS-90 (16 days), the growth of the otolith with increasing spine length was significantly greater in the flight - reared fish for all three otoliths, from the saccule (saggita), utricle (lapillus) and lagena (astericus). However, juvenile fish, 1 cm long at launch, showed no significant difference in otolith size between flight - and ground-reared animals. In very early stage larvae from STS-89 (9 days), with spine length of 1.5 to 3.5 mm, the utricular and saccular otoliths were actually larger in the ground-reared larvae. Thus, it appears that late-stage fish embryos reared in space do produce larger-than - normal otoliths, apparently in an attempt to c mpensate for the reduced weight ofo the test mass in space. However, the results from very early-stage larvae and juvenile fish suggest that there is a fairly short critical period during which altered gravity can affect the size of the test mass. Recent studies on the development of the inner ear of the zebrafish (Danio raria) may explain the critical period for gravitational effects on otolith growth. By 16 hours after zebrafish fertilization (at 28.5 o

  5. Construction of a medicinal leech transcriptome database and its application to the identification of leech homologs of neural and innate immune genes

    Directory of Open Access Journals (Sweden)

    Wincker Patrick

    2010-06-01

    evolutionarily conserved sequences, representing all known pathways involved in these important functions. Conclusions The sequences obtained for Hirudo transcripts represent the first major database of genes expressed in this important model system. Comparison of translated open reading frames (ORFs with the other openly available leech datasets, the genome and transcriptome of Helobdella robusta, shows an average identity at the amino acid level of 58% in matched sequences. Interestingly, comparison with other available Lophotrochozoans shows similar high levels of amino acid identity, where sequences match, for example, 64% with Capitella capitata (a polychaete and 56% with Aplysia californica (a mollusk, as well as 58% with Schistosoma mansoni (a platyhelminth. Phylogenetic comparisons of putative Hirudo innate immune response genes present within the Hirudo transcriptome database herein described show a strong resemblance to the corresponding mammalian genes, indicating that this important physiological response may have older origins than what has been previously proposed.

  6. ENZYME KINETICS OF APLYSIN METABOLISM IN RAT LIVER MICROSOMES%海兔素在大鼠肝微粒体中的酶促反应动力学研究

    Institute of Scientific and Technical Information of China (English)

    丰暖; 梁惠; 马爱国; 张辉珍

    2015-01-01

    Objective To establish a HPLC method for the determination of aplysin in rat liver microsome, and study the enzyme kinetics of aplysin metabolism in rat liver microsome, as well as the effect of CYP3A inhibitor ketoconazole. Methods A HPLC method was developed for the determination of aplysin. Aplysin was incubated in rat liver microsome for 30 min. The effects of different incubation times and liver microsomal protein concentrations on alysin metabolism were observed. Lineweave-Burk graphic method was used to calculate the enzyme kinetic parameters. Ketoconazole (0.5, 2, 5, 10, 20, 40 mg/L) was used to inhibit the metabolism of aplysin in vitro. Results The linear range of aplysia standard curve was 0.5-100 mg/L. The intra- and inter-day RSDs were less than 3.18%. The recovery rate was 96.19%-97.83%, and a good stability at room temperature for 24 h or at -200C for a week was confirmed. The best incubation conditions for aplysin metabolism in rat liver microsome were 30 min for incubation time and 1 mg/mL for protein concentration. The enzyme kinetic parameters were as follows: Km 19.72 mg/L, Vmax 0.35 mg/min/g protein, CLint 17.75 ml/(min·g) protein. Ketoconazole was inhibitory to the metabolism of aplysin in vitro. Conclusion The established HPLC method is fast, simple, specific and sensitive and applicable in the study of the enzyme kinetics of aplysin metabolism in rat liver microsome. CYP3A may be involved in the metabolism of aplysin.%目的建立测定大鼠肝微粒体孵育液中海兔素含量的高效液相色谱法(HPLC),研究海兔素在大鼠肝微粒体中代谢的酶动力学以及CYP3A特异性抑制剂酮康唑对其代谢反应的影响。方法考察不同孵育时间、肝微粒体蛋白浓度、海兔素浓度对代谢反应的影响,并采用双倒数作图法计算海兔素的酶促反应动力学参数;观察不同浓度酮康唑(0.5,2,5,10,20,40 mg/L)对海兔素体外代谢的影响。结果海兔素的

  7. EDITORIAL: Special issue on optical neural engineering: advances in optical stimulation technology Special issue on optical neural engineering: advances in optical stimulation technology

    Science.gov (United States)

    Shoham, Shy; Deisseroth, Karl

    2010-08-01

    and Chalazonitis N 1961 Excitatiory and inhibitory processes initiated by light and infra-red radiations in single identifiable nerve cells Nervous Inhibition ed. E Florey (New York: Pergamon) pP 194-231 [5] Fork R L 1971 Laser stimulation of nerve cells in Aplysia Science 171 907-8 [6] Allegre G, Avrillier S and Albe-Fessard D 1994 Stimulation in the rat of a nerve fiber bundle by a short UV pulse from an excimer laser Neurosci. Lett. 180 261-4 [7] Hirase H, Nikolenko V, Goldberg J H and Yuste R 2002 Multiphoton stimulation of neurons J. Neurobiol. 51 237-47 [8] Callaway E M and Yuste R 2002 Stimulating neurons with light Curr. Opin. Neurobiol. 12 587-92 [9] Ellis-Davies G C 2007 Caged compounds: photorelease technology for control of cellular chemistry and physiology Nat. Methods 4 619-28 [10] Shoham S, O'Connor D H, Sarkisov D V and Wang S S 2005 Rapid neurotransmitter uncaging in spatially defined patterns Nat. Methods 2 837-43 [11] Nikolenko V, Poskanzer K E and Yuste R 2007 Two-photon photostimulation and imaging of neural circuits Nat. Methods 4 943-50 [12] Lutz C, Otis T S, DeSars V, Charpak S, DiGregorio D A and Emiliani V 2008 Holographic photolysis of caged neurotransmitters Nat. Methods 5 821-7 [13] Nikolenko V, Watson B O, Araya R, Woodruff A, Peterka D S and Yuste R 2008 SLM microscopy: scanless two-photon imaging and photostimulation with spatial light modulators Front. Neural Circuits 2 5 [14] Zahid M, Velez-Fort M, Papagiakoumou E, Ventalon C, Angulo M C and Emiliani V Holographic photolysis for multiple cell stimulation in mouse hippocampal slices PLoS One 5 e9431 [15] Boyden E S, Zhang F, Bamberg E, Nagel G and Deisseroth K 2005 Millisecond-timescale, genetically targeted optical control of neural activity Nat. Neurosci. 8 1263-8 [16] Zhang F, Aravanis A M, Adamantidis A, de Lecea L and Deisseroth K 2007 Circuit-breakers: optical technologies for probing neural signals and systems Nat. Rev. Neurosci. 8 577-81 [17] Gradinaru V, Zhang F, Ramakrishnan