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PubMed1984

The probable origin of an anemone cell tumor: metastatic transitional cell carcinoma producing HCG.

A neoplasm of unknown origin in cervical and axillary lymph nodes was diagnosed as anemone cell tumor by ultrastructural examination. Three years after the initial diagnosis of anemone cell tumor, a high-grade transitional cell carcinoma of the bladder was discovered. The results of immunoperoxidase staining of the cervical lymph node, axillary lymph node, and bladder tumors for keratin, carcinoembryonic antigen, and human chorionic gonadotropin (HCG) strongly suggest that the anemone cell tumors in this case represent metastases of bladder carcinoma cells capable of producing HCG.

Axilla↗
PubMed1999

Characterization of outer arm dynein in sea anemone, Anthopleura midori.

Outer arm dynein was purified from sperm flagella of a sea anemone, Anthopleura midori, and its biochemical and biophysical properties were characterized. The dynein, obtained at a 20S ATPase peak by sucrose density gradient centrifugation, consisted of two heavy chains, three intermediate chains, and seven light chains. The specific ATPase activity of dynein was 1.3 micromol Pi/mg/min. Four polypeptides (296, 296, 225, and 206 kDa) were formed by UV cleavage at 365 nm of dynein in the presence of vanadate and ATP. In addition, negatively stained images of dynein molecules and the hook-shaped image of the outer arm of the flagella indicated that sea anemone outer arm dynein is two-headed. In contrast to protist dyneins, which are three-headed, outer arm dyneins of flagella and cilia in multicellular animals are two-headed molecules corresponding to the two heavy chains. Phylogenetic considerations were made concerning the diversity of outer arm dyneins.

Animals↗
PubMed1997

Ultrastructure of neurons and synapses in the tentacle epidermis of the sea anemone Calliactis parasitica.

The anatomical organization of neutrons and synaptic pathways in tentacles of sea anemones is poorly understood. Transmission electron microscopy of serial thin sections was carried out on various regions of tentacles of the sea anemone Calliactis parasitica in order to locate and characterize typical epidermal neutrons and synapses. Both surface-oriented sensory cells with ciliary cones and basally located ganglion cells lacking a cilium have Golgi-derived granular or faintly cored vesicles. Similar vesicles are present at synaptic loci on some ganglion and muscle cells. The synaptic contacts on the longitudinal muscle cells are generally en passant rather than terminal. They vary from single neuromuscular synapses to pairs of neurites innervating the same muscle cell or one neurite innervating two or more muscle cells. Both two-way and one-way interneuronal synapses with vesicles aligned at paired synaptic membranes with dense material in a 14-20-nm-wide cleft are present in the epidermal nerve plexus. The vesicles average from 50 to 80 nm in diameter and vary from electron lucent to faintly cored. The results of this study demonstrate the presence of a complex system of epidermal neuronal pathways with specific synaptic loci in this modern representative of a first-evolved nervous system.

Animals↗
PubMed1999

Ultrastructure of neuro-spirocyte synapses in the sea anemone Aiptasia pallida (Cnidaria, Anthozoa, Zoantharia).

Using transmission electron microscopy of serially sectioned tentacles from the sea anemone Aiptasia pallida, we located and characterized two types of neuro-spirocyte synapses. Clear vesicles were observed at 10 synapses and dense-cored vesicles at five synapses. The diameters of vesicles at each neuro-spirocyte synapse were averaged; clear vesicles ranged from 49-89 nm in diameter, whereas the dense-cored vesicles ranged from 97-120 nm in diameter. One sequential pair of synapses included a neuro-spirocyte synapse with clear vesicles (81 nm) and a neuro-neuronal synapse with dense-cored vesicles (168 nm). A second synapse on the same cell had dense-cored vesicles (103 nm). An Antho-RFamide-labeled ganglion cell and three different neurites were observed adjacent to spirocytes, but no neuro-spirocyte synapses were present. Many of the spirocytes also were immunoreactive to Antho-RFamide. The presence of sequential neuro-neuro-spirocyte synapses suggests that synaptic modulation may be involved in the neural control of spirocyst discharge. The occurrence of either dense-cored or clear vesicles at neuro-spirocyte synapses suggests that at least two types of neurotransmitter substances control the discharge of spirocysts in sea anemones.

Animals↗
PubMed2001

Neuroglandular synapses in the pharynx of the sea anemone Aiptasia pallida (Cnidaria, Anthozoa).

Scanning and transmission electron microscopy of the pharynx of the sea anemone Aiptasia pallida revealed a heavily ciliated epidermis and two types of gland cells not known previously to be innervated. By tracing serial cross sections of the pharynx, we located and characterized two types of neuroglandular synapses (i.e., those having clear vesicles and those with dense-cored vesicles). The diameters of the vesicles at each synapse were averaged; clear vesicles ranged from 70 to 103 nm in diameter and were observed at synapses to both mucous and zymogenic gland cells. Dense-cored vesicles ranged from 53 to 85 nm in diameter and were observed at synapses to two mucous gland cells. One mucous gland cell had three neuroglandular synapses, one with clear vesicles and two with dense-cored vesicles. The occurrence of either clear or dense-cored vesicles at neuroglandular synapses suggests that at least two types of neurotransmitter substances control the secretion of mucus in the sea anemone pharynx. To date, only clear vesicles have been observed at a neurozymogenic gland cell synapse in the pharynx. No evidence of immunoreactivity to phenylethanolamine-N-methyl transferase was observed at neuroglandular synapses, suggesting that adrenaline is not a transmitter in the pharynx of A. pallida.

Animals↗
PubMed1995

Chemoreceptor-mediated polymerization and depolymerization of actin in hair bundles of sea anemones.

Hair bundles located on tentacles of sea anemones are morphodynamic mechanoreceptors employed to regulate discharge of nematocysts into swimming prey. Activation of chemoreceptors for N-acetylated sugars is known to induce anemone hair bundles to elongate while shifting discharge to lower frequencies matching those produced by calmly swimming prey. In the continued presence of N-acetylated sugars, activation of proline receptors is known to induce hair bundles to shorten while shifting nematocyst discharge to higher frequencies presumed to correspond to movements produced by wounded, struggling prey. In the present study, N-acetylneuraminic acid (NANA) causes stereocilia to become more intensely fluorescent in confocal optical sections of phalloidin-stained specimens, suggesting that receptors for N-acetylated sugars initiate processes to increase the density of F-actin within stereocilia. Computer analysis of electron micrographs is consistent with this interpretation for large diameter stereocilia but not for small diameter stereocilia. In the continued presence of NANA, proline causes fluorescence intensity of phalloidin to decrease to or below control levels. DNaseI uniformly stains large diameter stereocilia, suggesting that these stereocilia contain a pool of G-actin. Fluorescence intensity of DNaseI in stereocilia is significantly less bright in specimens exposed to NANA alone than in specimens exposed to proline in the continued presence of NANA. It appears that whereas activated receptors for NANA induce G-actin to polymerize in large diameter stereocilia, activated receptors for proline induce F-actin to depolymerize, restoring G-actin pools.

Actins↗
PubMed2002

Ultrastructural evidence for two-cell and three-cell neural pathways in the tentacle epidermis of the sea anemone Aiptasia pallida.

Sensory and ganglion cells in the tentacle epidermis of the sea anemone Aiptasia pallida were traced in serial transmission electron micrographs to their synaptic contacts on other cells. Sensory cell synapses were found on spirocytes, muscle cells, and ganglion cells. Ganglion cells, in turn, synapsed on sensory cells, spirocytes, muscle cells, and other neurons and formed en passant axo-axonal synapses. Axonal synapses on nematocytes and gland cells were not traced to their cells of origin, i.e., identified sensory or ganglion cells. Direct synaptic contacts of sensory cells with spirocytes and sensory cells with muscle cells suggest a local two-cell pathway for spirocyst discharge and muscle cell contraction, whereas interjection of a ganglion cell between the sensory and effector cells creates a local three-cell pathway. The network of ganglion cells and their processes allows for a through-conduction system that is interconnected by chemical synapses. Although the sea anemone nervous system is more complex than that of Hydra, it has similar two-cell and three-cell effector pathways that may function in local responses to tentacle contact with food.

Animals↗
PubMed2000

Cloning of a novel G-protein-coupled receptor from the sea anemone nervous system.

We describe the cloning and analysis of genomic and cDNA copies of a gene from sea anemones that encodes a new member of the G-protein-coupled receptor family. The receptor shows similarity to previously described receptors for biogenic amines such as adrenaline, serotonin, and octopamine, as well as a variety of small molecule agonists and peptides, although we have been unable to determine which ligand is the natural agonist. Antibodies generated against the recombinant receptor protein identify a single protein with a molecular weight of 66 kDa in membrane preparations. Immunofluorescence studies using the same antibody have enabled localization of the receptor in the nervous system. Western blotting and RT-PCR analysis reveal that a homologue of this receptor is expressed in jellyfish and soft coral. We suggest that the receptor plays a role in neurotransmission in the sea anemone and other members of the phylum Cnidaria.

Amino Acid Sequence↗
PubMed2000

Genomic organization and splicing variants of a peptidylglycine alpha-hydroxylating monooxygenase from sea anemones.

Cnidarians are primitive animals that use neuropeptides as their transmitters. All the numerous cnidarian neuropeptides isolated, so far, have a carboxy-terminal amide group that is essential for their actions. This strongly suggests that alpha-amidating enzymes are essential for the functioning of primitive nervous systems. In mammals, peptide amidation is catalyzed by two enzymes, peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL) that act sequentially. These two activities are contained within one bifunctional enzyme, peptidylglycine alpha-amidating monooxygenase (PAM), which is coded for by a single gene. In a previous paper (F. Hauser et al., Biochem. Biophys. Res. Commun. 241, 509-512, 1997) we have cloned the first known cnidarian PHM from the sea anemone Calliactis parasitica. In the present paper we have determined the structure of its gene (CP1). CP1 is >12 kb in size and contains 15 exons and 14 introns. The last coding exon (exon 15) contains a stop codon, leaving no room for PAL and, thereby, for a bifunctional PAM enzyme as in mammals. Furthermore, we found a CP1 splicing variant (CP1-B) that contains exon-9 instead of exon-8, which was present in the previously characterized PHM cDNA (CP1-A). CP1-A and -B have 97% amino acid sequence identity, whereas both splicing variants have around 42% sequence identity with the PHM part of rat PAM. Essential amino acid residues for the catalytic activity and the 3D structure of PHM are conserved between CP1-A, -B and the PHM part of rat PAM. Furthermore, eight introns in CP1 occur in the same positions and have the same intron phasing as eight introns in the rat PAM gene, showing that the sea anemone PHM is not only structurally, but also evolutionarily related to the PHM part of rat PAM.

Alternative Splicing↗
PubMed1993

Sequential 1H-NMR assignments of neurotoxin III from the sea anemone Heteractis macrodactylus and structural comparison with related toxins.

The complete sequence-specific assignment of resonances in the 1H-NMR spectrum of the polypeptide neurotoxin III (Hm III) from the sea anemone Heteractis macrodactylus is described. Comparison of the chemical shifts and pattern of NOEs for Hm III with those for the related toxin Hp III from Heteractis paumotensis, which differs only in the substitution of Asn for Tyr at position 11, shows that the overall secondary and tertiary structures are conserved. The largest differences in chemical shift caused by the substitution at position 11 are observed for the NH resonances of Arg-13, Thr-14, Ala-15, Leu-17, and Cys-26. The C alpha H resonances influenced most are those of ASP-6, Gly-9, Leu-17, and Glu-42, while the most affected C beta H resonances are from Leu-17, Glu-28, and Lys-32. The absence of long-range NOEs to the aromatic ring of Tyr-11 as well as the lack of significant chemical shift effects on residues outside the loop comprising residues 7-16 confirm that this part of the loop makes no long-lived contacts with the rest of the molecule. The deviations from random coil shifts of Hm III are compared with those of the related anemone toxins Hp II, Hp III, and toxin I from Stichodactyla helianthus (Sh I). The similarity in deviations in chemical shift as a function of sequence position for these four toxins emphasizes the overall structural homology among these polypeptides.

Amino Acid Sequence↗
PubMed1983

Evidence of dopa in the nerves of sea anemones.

An analysis of the presence of catechol-derivatives in the sea anemones Metridium senile and Tealia felina, made with the aid of high-pressure liquid chromatography (HPLC), established the presence of dopa, 5-OH-dopa, and 5-S-cysteinyldopa. In addition, 2-S-cysteinyldopa and 2.5-diSS-cysteinyldopa occurred in Metridium. Two unknown substances were found to be present in the tentacles of Metridium and in the tentacles of some specimens of Tealia. Neither catecholamines nor serotonin could be traced in detectable amounts. No dopa-decarboxylase could be demonstrated by the assay performed in this investigation. 6-OH-dopa, 6-OH-dopamine and reserpine had no effect on the formaldehyde-induced fluorescence of the subepithelial tentacular nerve net of Tealia. It is concluded that the tentacular nerve net of sea anemones contains dopa, but neither catecholamines nor serotonin. The localization of the other compounds is not yet established.

Animals↗
PubMed2006

Peptide toxins in sea anemones: structural and functional aspects.

Sea anemones are a rich source of two classes of peptide toxins, sodium channel toxins and potassium channel toxins, which have been or will be useful tools for studying the structure and function of specific ion channels. Most of the known sodium channel toxins delay channel inactivation by binding to the receptor site 3 and most of the known potassium channel toxins selectively inhibit Kv1 channels. The following peptide toxins are functionally unique among the known sodium or potassium channel toxins: APETx2, which inhibits acid-sensing ion channels in sensory neurons; BDS-I and II, which show selectivity for Kv3.4 channels and APETx1, which inhibits human ether-a-go-go-related gene potassium channels. In addition, structurally novel peptide toxins, such as an epidermal growth factor (EGF)-like toxin (gigantoxin I), have also been isolated from some sea anemones although their functions remain to be clarified.

Amino Acid Sequence↗
PubMed2000

Evidence for the presence of 1,2-cyclic acetal type sn-glycero-3-phosphoethanolamines in the sea anemone, Actiniogeton sp.

Five 1,2-cyclic acetal-type sn-glycero-3-phosphoethanolamines (CGPE) were isolated in a pure state from the sea anemone, Actiniogeton sp. (Coelenterata). Their structures, including the absolute configurations, have been determined on the basis of chemical and spectral data to be so-called Feulgen's acetalphosphatides, which have been regarded as artifacts derived from original plasmalogens. We examined whether these CGPE are intact constituents in the animal tissues and obtained reliable confirmation that CGPE are normally present in the sea anemone.

Animals↗
PubMed1991

Isolation of L-3-phenyllactyl-Phe-Lys-Ala-NH2 (Antho-KAamide), a novel neuropeptide from sea anemones.

We have isolated and sequenced the neuropeptide L-3-phenyllactyl-Phe-Lys-Ala-NH2 from the sea anemone Anthopleura elegantissima. This neuropeptide (named Antho-KAamide) has the unusual N-terminal L-3-phenyllactyl blocking group which has recently also been discovered in 2 other neuropeptides from sea anemones. We propose that the L-3-phenyllactyl residue renders Antho-KAamide resistant to nonspecific aminopeptidases, thereby increasing the stability of the neuropeptide after neuronal release. The existence of the L-3-phenyllactyl residue in 3 neuropeptides isolated so far suggests that this blocking group is more generally occurring.

Amino Acid Sequence↗
PubMed1988

Isolation of less than Glu-Ser-Leu-Arg-Trp-NH2, a novel neuropeptide from sea anemones.

Using a radioimmunoassay for the peptide sequence Arg-Phe-NH2, a peptide has been purified from acetic acid extracts of the sea anemone Anthopleura elegantissima. This peptide has the structure less than Glu-Ser-Leu-Arg-Trp-NH2. Using antisera to its carboxyterminal sequence Arg-Trp-NH2, the peptide was found to be exclusively localized in neurons of sea anemones, among them neurons associated with the sphincter muscle. This suggest that the peptide is a transmitter at neuromuscular junctions.

Animals↗
PubMed1975

Classical conditioning in the sea anemone, Cribrina xanthogrammica.

Earlier attempts to classically condition sea anemones have yielded inconclusive results. Using light as CS and shock as US, conditioning as distinguished from sensitization and pseudoconditioning was demonstrated in anemones. Procedural controls included substitution of light alone, shock alone, and random light and shock in place of paired light-shock trials. Responses measured were electrical output and folding of the oral disc. The conditioned response was distinguished from the unconditioned response to light and the unconditioned response to shock in terms of response latency of both electrical and behavioral measures.

Cnidaria↗
PubMed1982

Isolation and partial characterization of three lethal and hemolytic toxins from the sea anemone Actinia cari.

Three lethal and hemolytic toxins, caritoxin I, II and III were isolated from the sea anemone Actinia cari. Following controlled autolysis, tentacles were strained through a nylon sieve and thus a crude extract was obtained. The toxins were further purified by Sephadex G-75 gel chromatography. All three toxins which were eluted at the same peak, were separated by ion-exchange chromatography on CM-cellulose. Disc-PAGE revealed electrophoretic homogeneity of caritoxin II. Caritoxin I was obtained in pure form following rechromatography on CM-cellulose. Purified toxins were stable in the pH range 3 - 8. The preliminary determined molecular weight of the toxins was 20 - 25000 daltons. All three toxins are basic proteins. Isoelectric point of caritoxin I was determined as 10.7. The isolated toxins are lethal (LD 5o of caritoxin I is 22 microgram/kg mice, i.v.) and indicate high hemolytic activity with a pH optimum between 8 and 9. Sphingomyelin specifically and irreversibly inhibits the hemolytic activity of caritoxins as well as some other sea anemone cytolytic toxins.

Animals↗
PubMed1992

Actions of three structurally distinct sea anemone toxins on crustacean and insect sodium channels.

The membrane actions of three recently isolated polypeptide neurotoxins from the sea anemones Stichodactyla helianthus (toxin ShI), Condylactis gigantea (toxin CgII) and Calliactis parasitica (toxin CpI) were investigated on action potentials and voltage-clamp membrane currents of the giant axon of the crayfish Procambarus clarkii. The first two toxins were also tested on the cockroach (Periplaneta americana) giant axon. All three toxins were particularly lethal to crustaceans, moderately toxic to an insect (cockroach), and essentially non-toxic to a mammal (mouse). ShI and CgII were 50- to 100-fold more potent on crayfish than on cockroach axons; this difference in activity was correlated with the relative reversibility of their effects on these arthropod axons. The crustacean selectivity of these toxins is therefore due largely to their greater affinity for crustacean sodium channels. All three toxins prolonged crayfish giant axon action potentials by selectively slowing Na channel inactivation without greatly affecting activation. Before toxin treatment, inactivation was nearly exponential, with a time constant less than 1 msec. After treatment, the inactivation time course could be described as the sum of two exponentially decaying components, plus a large steady-state component. The major component possessed the slower (10-20 msec) time constant. The steady-state component increased with depolarization, causing the sodium channel steady-state inactivation curve to reach a minimum between -60 and -20 mV and then increase at more positive potentials. All three toxins shifted the peak sodium current-voltage relation to the left. This voltage shift was greater at 20 degrees C than at 10 degrees C. Maintained membrane depolarization during toxin wash-in delayed the appearance of modified Na channels. Also, prolonged depolarization of toxin-treated axons converted modified sodium channels back to normal ones. The toxins did not affect potassium and leakage currents. Our results indicate that the three crustacean-active sea anemone toxins share a common electrophysiological action on arthropod sodium channels, at least at the macroscopic level.

Action Potentials↗