Opisthobranch Mollusc Research Articles

Ultrastructural and physiological studies on the longitudinal body wall muscle of Dolabella auricularia. II. Localization of intracellular calcium and its translocation during mechanical activity.

The localization of Ca-accumulating structures in the longitudinal body wall muscle (LBWM) of the opisthobranch mollusc Dolabella auricularia and their role in the contraction-relaxation cycle were studied by fixing the LBWM fibers at rest and during mechanical response to 400 mM K or to 10(-4)--10(-3) M acetylcholine in a 1% OsO4 solution containing 2% K pyroantimonate. In the resting fibers, electron-opaque pyroantimonate precipitate was mostly localized at the peripheral structures, i.e., along the inner surface of the plasma membrane, at the membrane of the surface tubules, and at the sarcoplasmic reticulum. In the fibers fixed during mechanical activity, the precipitate was diffusely distributed in the myoplasm in the form of numerous particles with corresponding decrease in the amount of the precipitate at the peripheral structures. Electron-probe X-ray microanalysis showed the presence of Ca in the precipitate, indicating that the precipitate may serve as a measure of Ca localization. These results are in accord with the view that, in the LBWM, the Ca stored in the peripheral structures is released into the myoplasm to activate the contractile mechanism.

Tridachione, a propionate-derived metabolite of the opisthobranch mollusc Tridachiella diomedea

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTridachione, a propionate-derived metabolite of the opisthobranch mollusc Tridachiella diomedeaChris Ireland, D. John Faulkner, Barbara A. Solheim, and Jon ClardyCite this: J. Am. Chem. Soc. 1978, 100, 3, 1002–1003Publication Date (Print):February 1, 1978Publication History Published online1 May 2002Published inissue 1 February 1978https://doi.org/10.1021/ja00471a074RIGHTS & PERMISSIONSArticle Views147Altmetric-Citations42LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (296 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Homology of the giant serotonergic neurons (metacerebral cells) in Aplysia and pulmonate molluscs

The properties of the giant cerebral serotonin-containing neurons of the opisthobranch mollusc Aplysia californica were studied and were compared to the existing data on the giant serotonin-containing neurons (metacerebral cells) of pulmonate molluscs. Among the properties examined were: axonal distribution, synaptic input and output, pharmacological responses, biophysical characteristics, and plasticity. With only minor exceptions, the properties of the serotonin-containing neurons of Aplysia and of pulmonate molluscs were remarkably similar, and it was concluded that these identified neurons are true homologues. The establishment of the homology of the metacerebral cells of Aplysia to the metacerebral cells of pulmonate molluscs extends the known distribution of these neurons to a second major subclass ( Opisthobranchiata) of molluscs. Since pulmonate and opisthobranch molluscs differ substantially in behavioral and anatomical features, the study of the metacerebral cells of these two groups may promote the understanding of the evolutionary adaptation of the nervous system to different environmental pressures.

Intraspecific and Ontogenetic Radular Variation in Opisthobranch Systematics (Mollusca: Gastropoda)

Bertsch, H. (Galeta MaI'ine Laboraton], Sm.ithsonian Tropical Research. Institute, Canal Zone) 1976. Intraspeciiio and ontogenetic radular variation in opisthobranch system.atics (Mollusca: Gastropoda), Syst. Zool. 25:117-122,-New species of opisthobranch mollusks often have been erected on numerical differences of the radular teeth, Regression analyses of radular counts of Discodoris ecelinae (comprising also the synonymized species, D, hedgpethi) indicate intraspecific variation is ontogenetic. Predictions are given regarding the occurrence of this phenomenon among opisthobranchs, and suggestions are made for the use of radular characteristics in opisthobranch systematics. [Mollusca; Gastropoda; Discodoris; radula.] Many older taxonomic groups have turned out to be little more than size categories (Ghiselin, 1971). In particular, species of opisthobranch mollusks have often been differentiated based on size differences of the radulae or other parts of the anatomy, only later to be synonymized because researchers collect intermediate forms. Certain opisthobranch species have a wide range of radular variation in the number of rows of teeth, and the number of teeth per half-row. However, except for the anaspidean Phyllaplysia taylori Dall, 1900 (see Beeman, 1963) and phanerobranch nudibranchs of the genus Triopha Bergh, 1880 (Ferreira, in press), it has not been statistically proven with regression analyses that these variations do indeed indicate merely differences in size, not in taxa. The knowledge that such intraspecific variations occur should be applied to opisthobranch taxonomy in order to replace typological thinking with modern systematics (Mayr, 1969). This paper examines intraspecific radular variations between specimens of a cryptobranch dorid nudibranch as a growth sequence, and comments on the structural ontogeny of its radular teeth. 1Donner Laboratory and (mailing address:) Department of Zoology, University of California, Berkeley, California 94720. INTRASPECIFIC VABlATION Discodoris evelinae Marcus, 1955, was characterized as having 35 rows of teeth, and more than 77 teeth per half-row. Later, Discodoris hedgpethi Marcus, 1959, was described as a separate species because its radular formula was 26 rows of teeth and 44 teeth per half-row. With additional collections of specimens, animals with an intermediate number of teeth were found, and the radular difference became less. Eventually the two were synonymized (Marcus, 1971). Published records list the radular formula as 22-50 rows of teeth, with 40-80 teeth per half-row (Meyer, in press). Examination of 15 specimens of Discodoris evelinae that I collected from the Caribbean coast of Panama (July 29-September 1, 1974) reveals an even greater range of variation. The combined radular formula of these specimens is 16-35 rows, with maxima of 25-69 teeth per half-row. Some of these were smaller specimens than had previously been examined by other workers. A combined radular formula, although it prevents critical analysis, suggests that the number of tooth rows and individual teeth is dependent on the size of the specimen. This relationship can be demonstrated by using the data from each animal separately. FOl.U· size parameters were measured or counted: total length of living animal,

The effects of food deprivation on agonistic behavior in an opisthobranch mollusc, Hermissenda crassicornis

Behavioral observations of the encounters occurring among Hermissenda which had been deprived of food for 1–3 days demonstrated the following: 1. Although deprivation resulted in an increase of locomotor activity, there was not a corresponding increase in the number of encounters occurring. 2. Deprivation greatly increased the proportion of agonistic encounters. 3. As the deprivation period increased from 1 to 3 days, the proportion of agonistic encounters involving biting increased while the proportion of agonistic encounters without biting decreased. The overall proportion of agonistic encounters of both types appeared unchanged by the length of the deprivation.

Cyclopoid Copepods Associated With Opisthobranch Mollusks in New Caledonia

Trois Copepodes cyclopoides associes aux mollusques opisthobranches et jusqu'a present connus uniquement de Madagascar existent en Nouvelle-Caledonie, sur les memes hotes. Ce sont Anthessius dolabellae sur Dolabella auricularia ( = D. scapula), Doridicola audens sur Platydoris scabra, et Metaxymolgus commodus sur Hexabranchus flammulatus (= H. orbicularis et H. marginatus). Quelques details de l'anatomie externe sont decrits.

Distributed neuronal oscillators and efference copy in the feeding system of Pleurobranchaea.

Distributed neuronal oscillators and efference copy in the feeding system of Pleurobranchaea.William J. Davis, Melody V. S. Siegler, and George J. MpitsosWilliam J. Davis, Melody V. S. Siegler, and George J. MpitsosPublished Online:01 Mar 1973https://doi.org/10.1152/jn.1973.36.2.258MoreSectionsPDF (4 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByCorollary discharge inhibition of wind-sensitive cercal giant interneurons in the singing field cricketStefan Schöneich and Berthold Hedwig1 January 2015 | Journal of Neurophysiology, Vol. 113, No. 1Amino Acid-induced Reflexes and Their Neural Pathways in an Opisthobranch Mollusc Pleurobranchaea japonicaZoological Science, Vol. 18, No. 4Cross-correlation analysis of cerebrobuccal connective activity during Aplysia feeding behaviourComparative Biochemistry and Physiology Part A: Physiology, Vol. 106, No. 3Amino acids and serotonin in Limax maximus after a tryptophan devoid dietComparative Biochemistry and Physiology Part A: Physiology, Vol. 101, No. 1Cerebral interneurons controlling fictive feeding in Limax maximusJournal of Comparative Physiology A, Vol. 166, No. 3Cerebral interneurons controlling fictive feeding in Limax maximusJournal of Comparative Physiology A, Vol. 166, No. 3Morphology and function of the identified neuron B3 in the buccal ganglia of Helix pomatiaComparative Biochemistry and Physiology Part A: Physiology, Vol. 97, No. 1Neuronal analysis of pharyngeal peristalsis in the gastropod Navanax in terms of identified motoneurons innervating identified muscle bands. I. Muscle band identifiabilityBrain Research, Vol. 502, No. 2Relationships between a neuronal buccal population and the peribuccal regions in Aplsia: An electrophysiological studyComparative Biochemistry and Physiology Part A: Physiology, Vol. 93, No. 4Control of feeding movements in the freshwater snail Planorbis corneusExperimental Brain Research, Vol. 70, No. 2Input-output relationships of identified buccal neurones involved in feeding control in AplysiaBehavioural Brain Research, Vol. 16, No. 1Motivation and learning: Neurophysiological mechanisms in a “model” systemLearning and Motivation, Vol. 15, No. 4The pharmacology of molluscan neuronsProgress in Neurobiology, Vol. 23, No. 1-2A review of diets in the Notaspidea (Mollusca: Opisthobranchia)25 June 2013 | Journal of the Malacological Society of Australia, Vol. 6, No. 3-4Synaptic organization of expansion motoneurons ofNavanax inermisBrain Research, Vol. 195, No. 2Neuronal pathways involved in transfer of information related to leg position learning in the cockroach, P. AmericanaPhysiology & Behavior, Vol. 24, No. 3Behavioural hierarchiesTrends in Neurosciences, Vol. 2Neuronal events underlying rhythmic behaviors in invertebratesComparative Biochemistry and Physiology Part A: Physiology, Vol. 57, No. 2Rhythmic excitatory inputs to the lobster stomatogastric ganglionBrain Research, Vol. 101, No. 3Measurement of licking response execution in the ratPhysiology & Behavior, Vol. 12, No. 5 More from this issue > Volume 36Issue 2March 1973Pages 258-74 https://doi.org/10.1152/jn.1973.36.2.258PubMed4350359History Published online 1 March 1973 Published in print 1 March 1973 Metrics

Incorporation of [3H]-Leucine into protein by animal tissues and by endosymbzotic chloroplasts in Elysia viridis montagu

1. 1. Light microscopic and electron microscopic autoradiography have been used to study the incorporation of tritiated leucine into protein by the sacoglossan opisthobranch mollusc, Elysia viridis and its endosymbiotic chloroplasts acquired from the seaweed, Codium fragile. 2. 2. Light microscopic autoradioagraphy showed that several animal tissues incorporated [ 3H]-leucine into protein. Among these were the “secretory zones” of the digestive diverticulum, the testes and the pedal mucus gland. It is suggested that uptake of the metabolite was via the general integument. 3. 3. Electron microscopic autoradiography showed that protein in the chloroplasts becomes labelled after a 3-hr incubation, and the silver grain density over the chloroplasts does not change during a 1–12 hr “cold chase”. The possible sources of this protein are considered and evidence suggests that it is synthesized within the chloroplasts. 4. 4. Thus these chloroplasts have some degree of biochemical autonomy outside the algal cells.

Differential block at high frequency of branches of a single axon innervating two muscles.

Differential block at high frequency of branches of a single axon innervating two muscles.

Electrophysiological properties of dendrites and somata in alligator Purkinje cells.

Electrophysiological properties of dendrites and somata in alligator Purkinje cells.

Electrical transmission among neurons in the buccal ganglion of a mollusc, Navanax inermis.

The opisthobranch mollusc, Navanax, is carnivorous and cannibalistic. Prey are swallowed whole by way of a sudden expansion of the pharynx. The buccal ganglion which controls this sucking action was isolated and bathed in seawater. Attention was focused upon 10 identifiable cells visible on the ganglion's rostral side. Two cells were observed simultaneously, and each was penetrated with two glass microelectrodes, one for polarizing the membrane and the other for recording membrane potential variations. The coupling coefficients for direct current flow and action potentials of several identified cells were tabulated. Attenuation was essentially independent of the direction of current flow, but depended upon the relative size of the directly and indirectly polarized cells. The attenuation of subthreshold sinusoidally varying voltages increased with frequency above about 1 Hz. The coupling coefficient for spikes was lower than for DC due to greater high frequency attenuation. There is considerable similarity in the spontaneous PSP's of all cells, which is not due to the electrical coupling but to input from a common source. The 10 cells were not chemically interconnected but some were electrically connected to interneurons which fed back chemically mediated PSP's. The feedback can be negative or positive depending upon the membrane potential of the postsynaptic cell. We conclude that electrical coupling among the 10 cells plays a minor role in sudden pharyngeal contractions but that the dual electrical-chemical coupling with interneurons may be important in this respect.

OBSERVATIONS ON THE TECTIBRANCH RINGICULA BUCCINEA (BROCCHI)

Ringicula buccinea is an opisthobranch mollusc with a comparatively large external shell which burrows in muddy sand using its foot and cephalic disc. The latter helps to exclude sand from the mantle cavity, is produced into an inhalant siphon dorsally and is fused with the foot laterally. The gill is reduced and the main pallial water current is an exhalant one. There is no exogyrous caecum.Glands open just within the lips and the buccal cavity contains paired jaws and a reduced buccal mass and radula. Into it open the small salivary glands. The oesophagus has neither glands nor crushing plates. The stomach is large with the oesophagus, intestine and liver ducts opening close together to a thin‐walled anterior chamber, whereas a larger posterior chamber has thick, muscular walls and a cuticularized epithelium. Interstitial copepods and Foraminifera are collected for food and crushed in the triturating region.The rectum and pallial genital oviduct lie in the floor of the mantle cavity. A single duct carries both sperm and ova to the mouth of the cavity a bursa copulatrix and receptaculum are associated with it. The penis is retracted into a sheath which opens on the head and is associated with a prostate gland.Discussion of these aspects of the animal's structure confirms its position as a primitive tectibranch which is specialized for burrowing and also shows affinities with the basommatophoran pulmonates.

Chemical properties of the extract of salivary gland in Dolabella.

A protein extract was isolated from the salivary gland of Dolabella scopola, a marine opisthobranch mollusc. The extract was a kind of glycoprotein or glycoprotein-like substance, which was consisted from fourteen kinds of amino acid and one sugar. It caused a increase of calcium level in rat serum on the intraveneous administration and a transitory decrease of the number of leucocytes in rabbit followed by its successive increase.

Observations on the opisthobranch mollusc Acteon tornatilis (L.).

SummaryActeon tornatilis is an opisthobranch mollusc which burrows in sand, using foot, labial and cephalic tentacles in the process. The last also help to exclude sand from the mantle cavity, which is extended into a caecum coiling alongside the visceral hump, presumably used for respiration but also for excretion. The main pallial water current is an exhalant one on the right.The mantle skirt carries, on the left, numerous repugnatorial glands with toxic secretions.Labial glands lie at the mouth and the buccal cavity contains jaws and a reduced buccal mass and radula. Into it open salivary glands the structure of which is like that of the pyramidellids. The oesophagus shows traces neither of glands nor of torsion whereas the stomach, though simplified, has resemblances to that of a prosobranch.The reproductive system is shown to be different from previous descriptions. Male and female ducts are separate from the lower end of the little hermaphrodite duct. The former passes to a prostate from which a vas deferens leads to a large uninvaginable penis; the latter has associated albumen and mucous glands and there is a receptaculum seminis to the duct of which a ventral channel leads from the female aperture in the mantle cavity.Discussion of these aspects of the animal's structure confirms its position as the most primitive of the opisthobranchs.