(n.) A mollusk having a shell consisting of two lateral plates or valves joined together by an elastic ligament at the hinge, which is usually strengthened by prominences called teeth. The shell is closed by the contraction of two transverse muscles attached to the inner surface, as in the clam, -- or by one, as in the oyster. See Mollusca.
(n.) A pericarp in which the seed case opens or splits into two parts or valves.
(a.) Having two shells or valves which open and shut, as the oyster and certain seed vessels.
Example Sentences:
(1) Start your exploring at Bearreraig Bay, where, if you are lucky, you may find belemnites, ammonites and bivalves.
(2) To compare biochemical differences between bivalves with and without endosymbiotic chemoautotrophic bacteria, specimens of Solemya velum, a bivalve species known to contain bacterial endosymbionts, and the symbiont-free soft-shelled clam Mya arenaria, were collected from the same subtidal reducing sediments during October and November 1988.
(3) We have demonstrated that M. edulis, a marine bivalve mollusc, reacts to the vertebrate monokines interleukin-1, -6 and TNF.
(4) Total neutral and acidic glycosphingolipids were prepared from whole tissues of the sea-water bivalve, Meretrix lusoria, and the former preparation was further fractionated into subgroups by silicic acid column chromatography.
(5) The development of microparticulate food particles for marine suspension-feeders is discussed with respect to the difficulties of nutrient delivery in the aquatic environment and to feeding and digestion in crustacea and bivalve molluscs.
(6) Attempts to introduce infectious or foreign material into oysters and other bivalve mollusks usually involve force or trauma because of immediate, prolonged adduction of the tightly closing valves.
(7) This observation, together with the finding that the oyster shell has a strong affinity for virus, suggests that surface properties, rather than size, are the principal factors governing the accumulation of viruses by filter-feeding marine bivalves.
(8) Chromatin organization in the sperm of the bivalve mollusks results from the interaction between a discrete number of protamine-like proteins (PL) and DNA.
(9) There was the doll's house-sized two-pronged fork, and the bivalves themselves, pale and ivory against the silvered shell.
(10) Infectious pancreatic necrosis virus of fish, infectious bursal disease virus of chickens, Tellina virus and oyster virus of bivalve molluscs, and drosophila X virus of Drosophila melanogaster are naked icosahedral viruses with an electron microscopic diameter of 58 to 60 nm.
(11) The control measures consisted of the prohibition of the harvest and sale of all bivalve mollusks as well as a public warning to avoid the consumption of such shellfish.
(12) The ultrastructural morphology of peripheral neurons and associated structures in the bivalve mollusc.
(13) In 6 male baboons, the left kidney was bivalved and repaired using a fibrin adhesive (group A) or conventional suturing (group B).
(14) There are various types of photoproteins: the photoproteins of coelenterates, ctenophores and radiolarians require Ca2+ to trigger their luminescence; the photoproteins of the bivalve Pholas and of the scale worm appear to involve superoxide radicals and O2 in their light-emitting reactions; the photoprotein of euphausiid shrimps emits light only in the presence of a special fluorescent compound; the photoprotein of the millipede Luminodesmus, the only known example of terrestrial origin, requires ATP and Mg2+ to emit light.
(15) Most progress is being made in relation to lethal blood mutant neoplasms in Drosophila, leukaemias of farmed salmonids among the fishes, and among shellfish, the hemic sarcomas of bivalves.
(16) Distribution of MlOse4Cer and MlXOse5Cer in various bivalve and snail glycolipid extracts were screened in thin-layer immunobinding assays by using this purified specific antibody.
(17) In the haemolymph of the Tridacnid bivalve clams anti-galactans occur which do not have only glycosubstance precipitating and cell agglutinating properties, but also show mitogenic activity with respect to the blast transformation of human peripheral lymphocytes.
(18) The pericardial glands of three bivalve molluscs are composed of convoluted epithelium that appears as pouches on the auricles of Mytilus and as tubules in the connective tissue at the anterior-lateral sides of the pericardial cavity of Mercenaria and Anodonta.
(19) Four biotypes and five antigenic types of bacteria, pathogenic for the larvae of five species of bivalve mollusks, were isolated and described in some detail.
(20) Laboratory toxicity tests performed on the bivalve Cerastoderma edule submitted to sublethal concentrations of paper mill effluent revealed significant decreases of adenylate energy charge (AEC), and changes in the total adenylate pool were observed in a 24-hr period even for the lowest concentration of pollutant tested.
Radula
Definition:
(n.) The chitinous ribbon bearing the teeth of mollusks; -- called also lingual ribbon, and tongue. See Odontophore.
Example Sentences:
(1) Amongst heart, rectum and radula protractor muscles of Pila globosa, the heart showed a negative inotropic and negative chronotropic response while the rectum and radula protractor showed a positive tonotropic response to exogenously applied acetycholine (ACh).
(2) In the Aplysia accessory radula contractor muscle, prolonged exposure to serotonin or to the peptide transmitter small cardioactive peptide B, both of which produce large increases in intracellular cAMP, does not decrease regulatory subunits.
(3) We also obtained evidence that suggests that enough SCP is released under physiological conditions to modulate neuromuscular activity in the accessory radula closer.
(4) Most of the currently known FMRFamide-related peptides (FaRPs) of molluscs were tested in a radioimmunoassay (RIA) and in the two standard bioassays for FMRFamide: the radula protractor muscle of the whelk Busycon contrarium, and the isolated heart of the clam Mercenaria mercenaria.
(5) The cycle of radula movements consisted of three phases: quiescence (Q), protraction (P) and retraction (R).
(6) The SO makes reciprocal excitatory synapses with the N1 interneurons that drive the protraction of the radula.
(7) Acetone extract of the ganglia of Fusinus ferrugineus was applied to C-18 cartridges, and the flowthrough and retained materials were bioassayed on the radula retractor muscle of the animal.
(8) Movements of the radula and the hooks (which the Clione inserts into the body of its prey) as well as the electroneurogram of the radular nerve were recorded.
(9) The present results show that FMRFamide- and CARP-like peptides are involved in the regulation of the contraction of radula muscles and the heart beat.
(10) The siliceous radulae were examined histologically.
(11) The accessory radula closer (ARC) buccal muscles have been used to study this phenomenon, and it has been shown that changes in ARC muscle contraction are partially due to activity of a serotonergic neuron that modulates this muscle, by both a direct action and an action on two ARC motor neurons (B15 and B16).
(12) Corresponding to each radula movement was a burst of activity in the radular nerve, consisting of the protractor and the retractor components.
(13) In the radula muscles, FMRFamide-related peptides were suggested to act on presynaptic sites to enhance their contraction elicited by nerve stimulation, possibly by increasing the release of a main transmitter.
(14) Several peaks of FMRFamide-like bioactivity (Busycon radula protractor muscle assay) were detected with a linear gradient of 5 to 30% acetonitrile.
(15) The radula of snails is formed at the posterior end of the radular gland or pocket, and degraded at the same rate at its anterior end.
(16) In previous studies, we demonstrated that B15, one of the two cholinergic motor neurons of the accessory radula closer muscle of Aplysia, synthesizes two peptides, small cardioactive peptides A and B (SCPA and SCPB), that, when exogenously applied, increase the size and relaxation rate of muscle contractions elicited by motor neuron stimulation.
(17) The accessory radula closer (ARC) buccal muscle motor neuron B16 is buccalin-immunoreactive and it synthesizes a peptide with chromatographic properties identical to those of buccalin.
(18) Low concentrations (10(-9)-10(-8) M) of this substance not only excite the isolated clam heart, but also produce tonic contractions of the isolated radula protractor muscle of the whelk, Busycon contrarium.
(19) Nerve fibres containing vesicles with electron dense neurosecretory material (deduced from the diameter of 200--250 nm) are attached to this sheath or penetrate into it; they may be involved in the regulation of production and degradation processes during radula replacement.
(20) The MCCs potentiate contractions of a muscle utilized in biting, the accessory radula closer (ARCM), when contractions are elicited by stimulation of either of the two cholinergic motor neurons B15 or B16 that innervate the muscle.