Fruitful findings have been produced from five out of sixty cells which were obtained from each 63 individual Aplisia caught at the Jeju coast. Spiking patterns of three out of five cells, such as relaxation oscillator, bursting within a short time of the inter-burst interval, chaotic bursting, period doubling sequences, bursting with long trains of action potentials separated by short silent periods, regular repeated beating or elliptic bursting, and silent states had been changed in order as the temperature was lowered to 10 degrees C from 32 degrees C. In the intervals of every about 40 minutes repeated ups and downs of temperature produced similar firing patterns at the allowable temperature ranges. The other two cells showed difference from these. The amplitudes of the action potentials of the two cells will not be highly decreased in 24 hours. Average spike frequencies, the inter-burst interval, peak to peak spike amplitude of action potentials, minimum potential values are compared and analyzed by using the computer programme. The spike frequencies according to temperature show the distribution of bell type, with maximal spike frequencies at intermediate temperatures and minimal ones at either end. The most common pattern consist of high spike frequency during falling and low one during rising temperatures.
Action Potentials ; Aplysia* ; Fires ; Fruit ; Hot Temperature* ; Relaxation

The sea hare is a marine mollusk in the family Aplysiidae that has long been consumed as food. Rarely, toxic hepatitis can occur after eating sea hare. We herein discuss four cases of toxic hepatitis due to sea hare ingestion and review the relevant literature.
Aplysia ; Drug-Induced Liver Injury* ; Eating* ; Hares* ; Humans ; Mollusca

The serotonergic system in vertebrates and invertebrates has been a focus for over 50 years and will likely continue in the future. Recently, genomic analysis and discovery of alternative splicing and differential expression in tissues have increased the knowledge of serotonin (5-HT) receptor types. Comparative studies can provide useful insights to the wide variety of mechanistic actions of 5-HT responsible for behaviors regulated or modified by 5-HT. To determine cellular responses and influences on neural systems as well as the efferent control of behaviors by the motor units, preparations amenable to detailed studies of synapses are beneficial as working models. The invertebrate neuromuscular junctions (NMJs) offer some unique advantages for such investigations; action of 5-HT at crustacean NMJs has been widely studied, and leech and Aplysia continue to be key organisms. However, there are few studies in insects likely due to the focus in modulation within the CNS and lack of evidence of substantial action of 5-HT at the Drosophila NMJs. There are only a few reports in gastropods and annelids as well as other invertebrates. In this review we highlight some of the key findings of 5-HT actions and receptor types associated at NMJs in a variety of invertebrate preparations in hopes that future studies will build on this knowledge base.
Alternative Splicing ; Aplysia ; Drosophila ; Gastropoda ; Insects ; Invertebrates ; Knowledge Bases ; Neuromuscular Junction ; Serotonin ; Synapses ; Synaptic Transmission ; Vertebrates

We performed experiments using Aplysia neurons to identify the mechanism underlying the changes in the firing patterns in response to temperature changes. When the temperature was gradually increased from 11degrees C to 31degrees C the firing patterns changed sequentially from the silent state to beating, doublets, beating-chaos, bursting-chaos, square-wave bursting, and bursting-oscillation patterns. When the temperature was decreased over the same temperature range, these sequential changes in the firing patterns reappeared in reverse order. To simulate this entire range of spiking patterns we modified nonlinear differential equations that Chay and Lee made using temperature-dependent scaling factors. To refine the equations, we also analyzed the spike pattern changes in the presence of potassium channel blockers. Based on the solutions of these equations and potassium channel blocker experiments, we found that, as temperature increases, the maximum value of the potassium channel relaxation time constant, taun(t) increases, but the maximum value of the probabilities of openings for activation of the potassium channels, n(t) decreases. Accordingly, the voltage-dependent potassium current is likely to play a leading role in the temperature-dependent changes in the firing patterns in Aplysia neurons.
Aplysia ; Computer Simulation ; Fires ; Neurons ; Potassium ; Potassium Channel Blockers ; Potassium Channels ; Relaxation

The α3* nAChRs, which are considered to be promising drug targets for problems such as pain, addiction, cardiovascular function, cognitive disorders etc., are found throughout the central and peripheral nervous system. The α-conotoxin (α-CTx) LvIA has been identified as the most selective inhibitor of α3β2 nAChRs known to date, and it can distinguish the α3β2 nAChR subtype from the α6/α3β2β3 and α3β4 nAChR subtypes. However, the mechanism of its selectivity towards α3β2, α6/α3β2β3, and α3β4 nAChRs remains elusive. Here we report the co-crystal structure of LvIA in complex with Aplysia californica acetylcholine binding protein (Ac-AChBP) at a resolution of 3.4 Å. Based on the structure of this complex, together with homology modeling based on other nAChR subtypes and binding affinity assays, we conclude that Asp-11 of LvIA plays an important role in the selectivity of LvIA towards α3β2 and α3/α6β2β3 nAChRs by making a salt bridge with Lys-155 of the rat α3 subunit. Asn-9 lies within a hydrophobic pocket that is formed by Met-36, Thr-59, and Phe-119 of the rat β2 subunit in the α3β2 nAChR model, revealing the reason for its more potent selectivity towards the α3β2 nAChR subtype. These results provide molecular insights that can be used to design ligands that selectively target α3β2 nAChRs, with significant implications for the design of new therapeutic α-CTxs.
Animals ; Aplysia ; Binding Sites ; Conotoxins ; chemistry ; Crystallography, X-Ray ; Humans ; Protein Structure, Quaternary ; Receptors, Nicotinic ; chemistry

The cytoplasmic polyadenylation element (CPE)-binding protein (CPEB) binds to CPE containing mRNAs on their 3' untranslated regions (3'UTRs). This RNA binding protein comes out many important tasks, especially in learning and memory, by modifying the translational efficiency of target mRNAs via poly (A) tailing. Overexpressed CPEB has been reported to induce the formation of stress granules (SGs), a sort of RNA granule in mammalian cell lines. RNA granule is considered to be a potentially important factor in learning and memory. However, there is no study about RNA granule in Aplysia. To examine whether an Aplysia CPEB, ApCPEB1, forms RNA granules, we overexpressed ApCPEB1-EGFP in Aplysia sensory neurons. Consistent with the localization of mammalian CPEB, overexpressed ApCPEB1 formed granular structures, and was colocalized with RNAs and another RNA binding protein, ApCPEB, showing that ApCPEB1 positive granules are RNA-protein complexes. In addition, ApCPEB1 has a high turnover rate in RNA granules which were mobile structures. Thus, our results indicate that overexpressed ApCPEB1 is incorporated into RNA granule which is a dynamic structure in Aplysia sensory neuron. We propose that ApCPEB1 granule might modulate translation, as other RNA granules do, and furthermore, influence memory.
Animals ; Aplysia/genetics/*metabolism ; Fluorescence Recovery After Photobleaching ; RNA/genetics/metabolism ; Sensory Receptor Cells/*metabolism ; mRNA Cleavage and Polyadenylation Factors/genetics/metabolism/*physiology

Seafood is one of the common causes of food allergies to adults. The sea hare Aplysia kurodai is a marine mollusk which belongs to invertebrate gastropod that has been consumed as a food in Korea. Cases of acute toxic hepatitis after ingestion of sea hares have been reported, but few cases of allergic reactions to sea hare have been reported in the literature. A 33-year-old man was referred to our Emergency Department due to urticaria and periorbital/perioral swelling after eating sea hares. Approximately 10 years ago, he experienced similar allergic reactions to it. Skin prick and intradermal tests showed strong positive responses to crude sea hare allergen extract. He was diagnosed with food allergy to sea hares. We herein report the first case of sea hare allergy after ingestion.
Adult ; Angioedema* ; Aplysia ; Drug-Induced Liver Injury ; Eating* ; Emergency Service, Hospital ; Food Hypersensitivity ; Gastropoda ; Hares* ; Humans ; Hypersensitivity ; Intradermal Tests ; Invertebrates ; Korea ; Mollusca ; Seafood ; Skin ; Urticaria*

OBJECTIVETo apply conidia of Pyricularia Oryzae to the screening of antimitotic constituents from marine animal sea hare.

METHODTo extract and fractionate active portions from sea hare through detecting deformation of mycelia germinated from conidia of P. Oryzae P-2b, in comparison with the cytotoxic test results in vitro.

RESULTTwo active portions, of which IC50 against P388 and HL-60 was 23.4, 18.6 and 19.4, 12.5 micrograms.ml-1, respectively, were screened from this animal.

CONCLUSIONThis bioassay method was efficiently applied to the primary screening of antimitotic portions from marine animals for the first time. Being convenient, speedy and cheap, the screening model is suitable for the bioassay of active constituents from marine life.

Animals ; Antineoplastic Agents ; isolation & purification ; pharmacology ; Aplysia ; chemistry ; HL-60 Cells ; drug effects ; Humans ; Leukemia P388 ; pathology ; Materia Medica ; isolation & purification ; pharmacology ; Mice ; Mitosis ; drug effects ; Mitosporic Fungi ; physiology ; Tumor Cells, Cultured ; drug effects

Phosphodiesterases (PDEs) play a key role in the regulation of cyclic adenosine monophosphate (cAMP), which in turn mediates various cellular functions including learning and memory. We previously cloned and characterized three PDE4 isoforms (ApPDE4) from Aplysia kurodai. Using reverse transcription polymerase chain reaction (RT-PCR), we found that ApPDE4 isoforms are primarily expressed in the central nervous system. However, the detailed distribution of ApPDE4 mRNA in Aplysia individual ganglions was not evident. In this study, to determine the distribution of ApPDE4 mRNAs in Aplysia ganglions, we performed in situ hybridization (ISH) using a probe targeting ApPDE4, including the PDE catalytic domain. Interestingly, we found the strongest ISH-positive signals in the symmetrical bag cell clusters of the abdominal ganglion. The R2, R14, L7, L2 and L11 neurons in the abdominal ganglion, LP1 neuron in pleural ganglion, and metacerebral (MCC) neurons were ISH-positive. Mechanosensory neurons of the sensory cluster were also stained on the ventral aspect of the right and left pleural ganglia. Taken together, we found the detailed distribution of ApPDE4 mRNA in Aplysia ganglion and support their roles in serotonin (5-HT)-induced synaptic facilitation of Aplysia mechanosensory neurons.
Adenosine Monophosphate ; Aplysia* ; Catalytic Domain ; Central Nervous System ; Clone Cells ; Cyclic Nucleotide Phosphodiesterases, Type 4* ; Ganglia ; Ganglion Cysts ; In Situ Hybridization* ; Learning ; Memory ; Neurons ; Phosphoric Diester Hydrolases ; Polymerase Chain Reaction ; Protein Isoforms ; Reverse Transcription ; RNA, Messenger ; Serotonin