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The ultrastructure of Symbiodinium microadriaticum in vitro and in the type host Condylactis and Casseopeia is described and contrasted with previous observations on symbionts from Anemonia sulcata and the Pacific Tridacnidae. Its type description is emended with new electron microscopic observations and with a list of alternate hosts, including their distributions.

The cnidae situated in the acontial filaments of the sea-anemone, Diadumene luciae , were found to respond by eversion of the stinging threads to potassium or ammonium ions in the external medium, to electric current and to mechanical contact of certain solid matter, such as food objects, human hair or skin, cholesterol, etc. All of these agents proved to be without effect on the cnidae which had been isolated from the acontium. The above-mentioned responses of the cnidae in situ were prevented reversibly by ordinary kinds of anaesthetics. Such situations were largely in accord with those which had already been reported for the cnidae in the tentacles of Anemonia sulcata . The important finding obtained in the present study was that the presence of chloride ions in the external medium was a necessary factor for establishing the explosion responses of cnidae in situ , and that the stimulating agents could produce only “misfiring” extrusion of cnida bodies, when they were made to act in a medium which was poor in chloride content. These facts have led the writer to propose a hypothesis concerning the mechanism of cnida excitation, in which essential roles are ascribed to the external chloride ions as well as to the thin surface protoplasmic layer of acontium which covers the distal ends of of cnidae in situ .

A toxin of low molecular weight was isolated from tentacles of the sea anemone Anemonia sulcata P. Partially purified toxin was obtained by precipitation with ammonium sulphate, ion exchange chromatography on DEAE cellulose and chromatography on Sephadex G-50. The molecular weight of a partially purified toxin, probably a basic protein was approximately 6000 as determined by gel filtration. Disc electrophoresis of the partially purified toxin revealed four proteins. Heating for 15 min at 90°C inactivated the toxin. The toxic activity remained unchanged over 12 months when stored in frozen solution at −26°C. The ld 100 is 6 mg of the toxin per kg (rat) by i.v. injection. The toxin showed a cardiotropic action on the rat heart. When injected i.v. the toxin caused cardiac arrhythmia and fall of the arterial blood pressure.

1. The nature of the stimulus which causes discharge of the cnidae (nematocysts and spirocysts) in the tentacles of Anemonia sulcata has been studied. 2. The cnidoblasts behave as independent effectors. Contact with solid food or electric stimuli cause only local discharge. Repetitive electric stimulation at various frequencies causes spread of excitation far down the nerve net of the tentacle but the cnida discharge remains localized under the stimulating electrode. There is no physiological evidence for any connexion ofcnidoblasts with the nervous system. 3. The stimulus to the cnidoblast is primarily due to direct mechanical contact. Discharge is easily effected by solid food. It can also be effected by inert solids provided the mechanical stimulus is sufficiently intense. 4. The normal stimulus to the cnidoblast is not a directly chemical one. Most food solutions and solutions of food derivatives do not cause a discharge. Some strong food solutions cause a few scattered cnidae to discharge. This differs from the intense local discharge to solid food. 5. Immersion in solutions of certain surface-active substances, such as the lower fatty acids, bile salts and saponin, causes an immediate general discharge of all the cnidae. This differs from the normal discharge to solid food. 6. Although natural food solutions do not normally cause a discharge, the cnidae are easily discharged by contact when they are present. That is, food solutions sensitize the cnidoblasts to mechanical stimuli. 7. The sensitizing substance is not protein. But it is strongly adsorbed on to protein. It cannot be extracted with ethyl ether. But it can be extracted with ethyl alcohol or acetone. Alcohol extracts of food are very active in sensitizing the cnidoblasts to mechanical disturbance. 8. Water insoluble foods can sensitize cnidoblasts with which they come in contact. Sensitization by contact is almost instantaneous. It is suggested that normally sensitization is due to some surface active lipoid directly transferred to the cnidoblast by contact.

Anemonia sulcata resorbierte und akkumulierte tritiummarkierte l-Aminosauren aus Meerwasser, welche diesem in naturlicher Konzentration zugesetzt worden waren (70–700 nMol/l). Die Aufnahme erfolgte nahezu ausschlieslich ektodermal; der uberwiegende Teil der aufgenommenen und dann eingebauten Aminosauren befand sich auch nach langerer Inkubation im Ektoderm. Diese Tatsache ist auf unterschiedliche cytologische Differenzierungen von Ento- und Ektoderm zuruckzufuhren. Elektronenmikroskopische Aufnahmen zeigen, das nur das Ektoderm resorbierende Strukturen (Mikrovilli) besitzt. Die Aufnahmeraten waren (von naturlichen Konzentrationen ausgehend) fur die untersuchten Aminosauren verschieden hoch (2–10 μg/g Frischgewicht/h). Die aufgenommene Menge war von der Ausenkonzentration abhangig. Die Konzentrationen, unterhalb denen nur noch eine sehr geringe Aufnahme registriert werden konnte, schwankten fur die einzelnen Aminosauren zwischen 10 und 100 nMol/l. Eine Gruppe von Aminosauren (Phe, Lys, Leu, His, Pro) wurde vorwiegend in den Synthesestoffwechsel eingeschleust, eine andere (Gly und Ser) wurde uberwiegend oxydativen Prozessen zugefuhrt. Der Gehalt an freien Aminosauren von Tentakelgewebe wurde bestimmt. Die Konzentration von Glycin z.B. ist im Gewebe 107mal hoher als im Medium, aus dem noch resorbiert wird. Die Aufnahme erfolgt daher mit groster Wahrscheinlichkeit aktiv. Formale Berechnungen zeigen, das den Tieren durch die Aufnahme geloster organischer Verbindungen ein Energiegewinn erwachst; dieser liegt uber dem Energieverbrauch, der dem Sauerstoffverbrauch aquivalent ist.

1. 1. The Anemonia sulcata toxin ATX II is cardiotoxic and neurotoxic, and—at a high dose level—even lethal for the mouse, neurotoxic, but non-lethal for the frog, and has no adverse influence whatever on the Planaria and Tetrahymena; it even stimulates the growth of the Tetrahymena at a low dose level. 2. 2. It also induces imprinting in the Tetrahymena, as judged from the altered response of the latter to ATX II on re-exposure. 3. 3. No similar imprinting effect was demonstrable in mice.

Investigations have been carried out on the carotenoids in Anemonia sulcata (Pennant) and Actinia equina (L.) (Coelenterata: Anthozoa) from the Adriatic Sea. The presence of the carotenoids was determined by means of columnar and thin-layer chromatography. The following carotenoids were found: Anemonia sulcata: β-carotene, lutein-like (epoxy and free) and astaxanthin; Actinia equina: α-carotene, β-carotene, actinioerythrin, lutein-like (?) and astaxanthin (ester and free).

The photo synthetic pigments of the zooxanthellae found in the endodermal tissues of Anemonia sulcata have been identified by column chromatography and spectrophotometry analysis. They appear to be identical with those found among free-living species of Dinophyceae as well as the zooxanthellae of Pacific Madreporaria and Tridacnidae, and confirm the taxonomic relationship which tills symbiont has in common with these organisms.

The sea anemone Anemonia sulcata is the clinically most important Actinaria in the Adriatic Sea. Between 1965 and 1980, 55 patients stung by this cnidarian were seen at the Pula Medical Center in Istria, Yugoslavia. The majority of injuries were inflicted upon the upper extremities, chest, or abdomen. Pain and the appearance of small blanched papules surrounded by slightly reddened and edematous bases were the usually initiating manifestations. Linear lesions were sometimes seen. Vesicles, sometimes filled with serous fluid, localized discoloration, and the formation of bullae sometimes followed. Somnolence, dizziness, nausea, vomiting, muscle aches, and lid edema were reported in some cases. The treatment of these injuries in the northern Adriatic Sea and elsewhere is discussed.

We have studied the mechanism of action of the toxins isolated from Anemonia sulcata which were purified by G. Wunderer. We have shown that Toxin II is mainly cardiotoxic on rats, however, it displays neurotoxic effects. Furthermore, Toxins I and II release acetylcholine from isolated guinea pig ileum. We point out the analogy with scorpion venom action.

Poisonings caused by bites and stings of venomous animals have not lost their importance from most ancient times until today. Rather, one could say that they in some respects have become even more important due to some moments as: the interesting results of biochemical, pharmacological and immunological researches of their venoms, so as possibilities of their use in treatment and in preparation of drugs; the importation of venomous animals in loads of goods from countries with warm climate into countries where they normally would not be found; the increasing number of fanciers who keep in their terraria often very dangerous animals; the interest of most armies of the world for venomous animals and poisonings due to them. However, the author stressed the increasing importance of venomous stings and bites from the point of view of modern tourism. The epidemiological and clinical features of poisoning by some animals in tourists are described: so for instance the consequences of bites and stings of spiders, gad flies, scolopendras, scorpions, coelenterates and fishes.

In isolated guinea-pig papillary muscle ATX II prolonged the action potential duration to a lesser extent at high extracellular Ca++-concentrations. This is interpreted as an interference of Ca++ with ATX II-binding sites.

One-dimensional and two-dimensional photochemically induced dynamic nuclear polarisation (photo-CIDNP) nuclear magnetic resonance spectra have been recorded for the sea-anemone polypeptide cardiac stimulants anthopleurin-A and Anemonia sulcata toxins I and II. In anthopleurin-A and toxin II, all three Trp residues are accessible to the flavin dye, although Trp-23 in anthopleurin-A shows a weaker photo-CIDNP response than Trp-33 and Trp-45. Tyr-25 in anthopleurin-A also shows a strong response. In toxin I, Trp-23, Trp-33 and Tyr-45 (which replaces Trp in this molecule) are accessible to the dye. The pH dependences of the photo-CIDNP spectra of all three polypeptides have been examined. The response of Trp-33 increases significantly with pH. The two His residues of anthopleurin-A and toxin II display a response in their imidazole forms, but not their imidazolium forms. The surface accessibilities of Trp-23 and Trp-33 are discussed in relation to the interaction of these polypeptides with the Na+ channel.

Circular dichroism spectra and surface activities are reported for toxins II and III isolated from Anemonia sulcata. Toxin II is highly surface active and as a result possesses a synergistic effect with phospholipase A2. In complete contrast, toxin III lacks detectable surface activity. The presence of sodium dodecyl sulfate (2.5 mg · ml−1) failed to trigger large conformation changes in both toxins II and III. From a comparison of the sequences of toxins II and III it is suggested that the hydrophobic region 17–27 is responsible for the surface activity of toxin II.

In isolated papillary muscle of the guinea pig electrical and mechanical activity were recorded at a stimulation rate of 1/s. After a long period of rest (10 min) the contraction amplitude showed a monotonous adaptation to pre-rest controls whereas the time course of the changes in action potential duration (a.p.d.) was biphasic, i.e. after a rapid prolongation, a transient maximum was reached, which was followed by a much slower shortening in a.p.d. to control values.

The present work identifies the decapod crustaceans that associate with Anemonia sulcata on the southwestern Atlantic coast of Portugal and characterises their host use pattern. It determines whether the anemone is monopolised by any species, resulting in the exclusion of conspecifics or other decapods and, under laboratory conditions, it evaluates the degree of association between each species and A. sulcata. From all sampled anemones, 79% harboured at least 1 decapod crustacean, with the majority displaying either one or two specimens (32 and 24%, respectively). The most abundant species were the shrimp Periclimenes sagittifer and the crab Inachus phalangium (representing 36 and 31% of collected specimens, respectively), which displayed lasting associations and were commonly recorded among the tentacles of the host. The species Eualus occultus, E. complex cranchii, Clibanarius erythropus, Maja brachydactyla, Pilumnus hirtellus and Polybius (Necora) puber displayed short-term associations, were mainly present on the substratum near the base, and avoided the tentacles of A. sulcata. Periclimenes sagittifer and I. phalangium were only recorded alone or in heterosexual pairs, appearing to efficiently defend their host against conspecifics. The majority of recorded species only seem to temporarily associate with A. sulcata, in order to seek protection from predators when other shelters are unavailable. El presente trabajo identifica los crustáceos decápodos que viven asociados a la anémona Anemonia sulcata en la costa atlántica sudoccidental de Portugal y caracteriza las pautas de utilización de la especie hospedadora. Verifica si la anémona es monopolizada por alguna especie, resultando en la exclusión de conespecíficos u otros decápodos, y evalúa en condiciones de laboratorio el grado de asociación entre cada especie y A. sulcata. A partir de todas las anémonas muestreadas, el 79% ospedó como mínimo una especie de crustáceo decápodo, la mayor parte de ellas con uno o dos individuos (32 y 24% respectivamente). Las especies más abundantes fueron el camarón carideo Periclimenes sagittifer y el cangrejo Inachus phalangium (representando respectivamente el 36% y 31% de los individuos recolectados). Estas especies mostraron asociaciones duraderas y fueron muestreadas comunmente entre los tentáculos del huesped. Las especies Eualus occultus, E. complejo cranchii, Clibanarius erythropus, Maja brachydactyla, Pilumnus hirtellus y Polybius (Necora) puber mostraron asociaciones no duraderas, y estuvieron principalmente presentes sobre el sustrato cerca de la base de la anémona, evitando los tentáculos. Periclimenes sagittifer e I. phalangium solamente se hallaron sólos o en pares heterosexuales, y mostraron defender eficientemente su huésped contra conespecíficos. La mayoría de especies halladas sólo parecen asociarse temporalmente con A. sulcata para buscar protección contra predadores cuando otros refugios no están disponibles.

International audience; We investigated the antibacterial activity of Anemonia sulcata (Cnidaria, Anthozoa) tentacle and body acidic extracts. Biochemical purification consisted of first step on solid phase Sep-Pak C8 column followed by several HPLC runs on C18 column using different conditions. Anti-Micrococcus lysodeikticus activity has been detected in 40 % acetonitrile fractions. The resulting purified molecule from tentacles had a molecular mass determined by MALDI-TOF mass spectrum of 4946,299 Da and has been completely sequenced. Its aa sequence revealed identity with the Neurotoxin 2 (ATX-II), a Na + channel blocking toxins. Consequently, ATX-II appeared to display a dual role as toxin and as antibacterial.

Soleus and extensor digitorum longus muscles were isolated from rats. The muscles were exposed to ATX-II, a toxin isolated from extracts of the sea-anemone Anemonia sulcata . The toxin caused a dose-dependent increase in the frequency of miniature endplate potentials in both types of muscle. The increase in frequency could be reversed by the application of tetrodotoxin (TTX), and could be prevented by prior exposure of the muscles to TTX. It is concluded that ATX-II causes a sodium-dependent depolarization of the nerve-terminal membrane.

A new sphingosine derivative was isolated from A.sulcata; 1H and 13C NMR spectra are described.

It was observed during the summer of 1920 that specimens of the Long legged Spider-crab, Stenorhynchus phalangium Penn., which happened to be in the crowded tanks of the Roscoff Laboratory, were always to be found in the neighbourhood of specimens of Anemonia sulcata Penn. (Anthea cereus Ellis). That this was not merely accidental was shown when crabs, removed to a distance of over three feet, returned time after time to an Anemonia, passing on the way anemones of various species, as well as all manner of objects which might conceivably afford shelter. Of fifteen healthy crabs of this species observed during the past three summers, every one showed this tendency in greater or less degree. At least two of these crabs were found clinging to anemones of this species on the shore, between tide marks; but the subsequent behaviour of crabs dredged from deeper water was in no way different.

OUR observations1 show that sponge species of distant taxonomic position, even if they belong to different classes such as Calcispongiae and Demospongiae, may form bispecific cell aggregates after dissociation.

IN an earlier report1, it was concluded from evidence obtained by pharmacological tests and paper chromatography that 5-hydroxytryptamine was a constituent of the sea-anemones, Metridium senile and Calliactis parasitica. More 5-hydroxytryptamine-like material was obtainable from Metridium tentacles, with their nematocysts, than from body wall which is relatively free of nematocysts. This led to the suggestion that 5-hydroxytryptamine might be a pain-producing factor in these stinging organelles. An independent study2 of material released on discharge of isolated Metridium nematocysts yielded two hydroxyindoles tentatively identified by chromatography as 5-hydroxytryptophan and bufotenine. The identification of 5-hydroxytryptamine in Calliactis has now been made quite certain3,4. However, the very large amount found in the coelenteric organ of this species and the relatively small amount in tentacles, coupled with the finding of little 5-hydroxytryptamine in Metridium and Anemonia sulcata, led Mathias, Koss and Schachter3,4 to conclude that it is unlikely that 5-hydroxytryptamine is associated with nematocysts. Further evidence is now available that this conclusion may not be fully warranted.

THERE has in the past been considerable discussion concerning the nature of the stimulus which causes the nematocysts of Cœlenterates to discharge, In some cases, it is quite clear that the mechanical stimulus to the cnidoblast causes an, explosion of the enclosed nematocyst. But for the majority of nematocysts, discharge only takes place in the presence of food, and it has been suggested that the stimulus is essentially a chemical one. During a long series of experiments on the feeding of Anemonia sulcata, interesting evidence has been obtained as to the mode of excitation of nematocysts. In agreement with Parker and Van Alstyne1, I find the cnidoblasts of the tentacles of Anemonia are independent effectors. They respond, however, selectively to food. If touched by a clean glass rod, no discharge is normally obtained. If touched with a piece of human skin, there is copious discharge. The discharge, however, only takes place where there has been mechanical contact. Strong food solutions sometimes seem to cause spontaneous discharge of a few nematocysts. But it is easy to show that this is of no direct significance in the normal reaction. As a direct chemical stimulus, food is far less effective than certain surface-active substances such as bile salts (0.1 per cent), which produce a complete spontaneous discharge of the nematocysts. This action is, however, quite different from the normal response. Cotton wool soaked in dilute bile salts does not adhere to the tentacles ; the nematocysts being discharged, by the diffusing bile salt before contact is made. On the other hand, cotton wool soaked in food solution causes extensive discharge of nematocysts into the mass on contact. This is true even though the food solution employed is far below the concentration for spontaneous discharge. Clean cotton wool, soaked in sea water as a control, produces no discharge.

THE feeding mechanisms of coelenterates were the subject of much interest at the turn of the century, and were investigated by such notable biologists as Loeb1, Jennings2 and Parker3. Renewed consideration has been given to these problems in the past few decades largely through the work of Pantin4, who used the sea anemone, Anemonia sulcata, and more recently through the experiments of Loomis5. The latter, who showed that small amounts of the tripeptide reduced glutathione activated feeding in the fresh-water Hydra littoralis, directed attention toward the chemical activation of feeding6,7. But the question of mechanical stimulation of feeding, although demonstrated in some sea anemones by earlier workers2,8, has been neglected in recent years. In this communication, I describe some observations which show that the feeding response of the sea anemone Epiactis prolifera can be repeatedly activated by remarkably slight mechanical stimulation with inert objects.

ALTHOUGH much work has been carried out on the biochemistry and mechanism of discharge of cnidae in the phylum Cnidaria, the past decade in particular has shown a swing towards research on the actual stimulus for discharge, which, along with other aspects of nematocyst researches, has been reviewed by Picken and Skaer1. Pantin2 made a great advance in our understanding of this problem, working on cnidae in isolated tentacles of Anemonia sulcata. He concluded that the cnidae behave as independent effectors, a fact which must be established if a hypothesis based on external environmental stimuli is to be postulated without involving the nervous system.