(1) Because ctenophore and all other known metazoan mtDNA is circular, the shared occurrence of linear mtDNA in three of the four cnidarian classes suggests a basal position for the Anthozoa within the phylum.
(2) Cloning of three Antennapedia-related sequences from cnidarians provides evidence of ancient roles for homeobox genes early in metazoan evolution.
(3) Cnidocytes, the stinging cells of cnidarians, discharge nematocysts in response to physical contact accompanied by the stimulation of specific chemoreceptors.
(4) It is suggested that they may also be present as predominant components in nematocysts of other cnidarian species and thus might represent a class of compounds which is characteristic for a whole phylum of the animal kingdom.
(5) The principal sources of these agents are bacteria, higher fungi, cnidarians (coelenterates) and the venoms of snakes, insects and other arthropods.
(6) The presence of cholecystokinin (CCK), originally isolated from porcine small intestine, has been reported in a diversity of invertebrates ranging, from cnidarians to protochordates, but so far, not in echinoderms.
(7) Cnidarians arose from a protist ancestry different from the second group, the Bilateria.
(8) In these trees, cnidarians (Radiata) seemed to have evolved independently from the Bilateria, which is in contradiction with the general evolutionary view.
(9) It is present in all cnidarians and can be isolated without enzyme treatment.
(10) The ganglion has been compared to the nervous systems in cnidarians, some spiralians, and especially other hemichordates, echinoderms, and chordates; it is found to be of primitive rather than degenerate nature.
(11) We report the nucleotide sequence of eveC, a cnidarian eve-class homeobox; this is the first homeobox to be identified in any diploblastic organism, and is only the second eve-class in an invertebrate.
(12) We previously characterized annexin XII from the freshwater cnidarian Hydra vulgaris (Schlaepfer, D. D., D. A. Fisher, M. E. Brandt, H. R. Bode, J. Jones, and H. T. Haigler.
(13) This report describes the cloning and sequencing of both cDNA and genomic clones of GFP from the cnidarian, Aequorea victoria.
(14) Eggs from all of the animals considered are covered by complex vitelline envelopes except those of cnidarians.
(15) The application of molecular techniques to cnidarians can provide important insights into developmental processes and phylogenetic relationships both within the phylum Cnidaria and among the eumetazoa.
(16) A new system is described for the study of ECM-tissue interactions, using the ECM (called mesogloea) of various cnidarians and isolated striated muscle and endodermal tissue of jellyfish.
(17) gamma-Glutamyltransferase activity was studied in extracts of the cnidarian Hydra attenuata.
(18) The results show that: polyps under normal conditions have similar regeneration patterns, regardless of individual variability; and ATxII, a neurotoxin of cnidarian origin, produces a statistically significant increase in the Tentacle Regeneration Index.
(19) In the context of earlier observations in cnidarians, these cytological features suggest a sensory as well as a modulatory function for 5-HT in Renilla koellikeri.
(20) Specifically, sperm eggs from cnidarians, echinoderms, decapod crustaceans, ascidians, lampreys, bony fishes, and amphibians are discussed.
Nematocyst
Definition:
(n.) A lasso cell, or thread cell. See Lasso cell, under Lasso.
Example Sentences:
(1) Nematocyst capsules and everted threads from both species contained levels of glycine and proline-hydroxyproline characteristic of vertebrate collagens.
(2) Purified nematocyst capsules and threads are rich in hydroxyproline, and dissolved by disulfide reducing agents.
(3) Investigation on important medusae and the chemistry of their nematocyst venoms have been expanding.
(4) They are considered to be the principal toxins injected by C. fleckeri during nematocyst discharge and appear to be different from the C. fleckeri toxins described by other workers.
(5) A new cytolysin has been isolated from the nematocysts of the jellyfish, Rhizostoma pulmo, and named rhizolysin.
(6) A comparison of methods for preparing a jellyfish nematocyst suspension from sea nettle (Chrysaora quinquecirrha) fishing tentacles at the beachside was conducted.
(7) Evidence obtained from the osmotic behavior of nematocysts, as well as data from in vitro exchange of their cations, are consistent with a physicochemical model in which the internal osmotic pressure of nematocysts and thus their ability to discharge is governed by the cationic composition of the content and the salt concentrations in the environment.
(8) Cnidocytes, the stinging cells of cnidarians, discharge nematocysts in response to physical contact accompanied by the stimulation of specific chemoreceptors.
(9) In the tentacles, neurons with long processes contacted up to five different batteries of nematocysts.
(10) It is suggested that they may also be present as predominant components in nematocysts of other cnidarian species and thus might represent a class of compounds which is characteristic for a whole phylum of the animal kingdom.
(11) Electrophoretic characterization of nematocyst extracts allows resolution of small proline-rich polypeptides that correspond in size to the cloned sequences.
(12) The major protein component present in the capsule and thread of a sea anemone nematocyst consists of monomers of a collagen-like protein linked by disulfide bonds.
(13) First-aid measures designed to prevent additional nematocyst rupture are species-specific.
(14) One such defective strain, called nem-4, contains virtually no stenoteles, one of the four types of nematocysts present in hydra, in its tentacles.
(15) The CSMs become predisposed to initiate nematocyst discharge into static (i.e., nonvibrating) test probes in the presence of submicromolar free and conjugated N-acetylated sugars, a process referred to as sensitization.
(16) It is suggested that the high concentration of calcium in the nematocysts accounts for their staining by cobalt and morin.
(17) Crude extract prepared from isolated and purified nematocysts (stenoteles, desmonemes, isorhizas) of Hydra attenuata Pall.
(18) Contrary to some previous reports in the literature, it has been found that spirocysts normally discharge by eversion, as do nematocysts.
(19) Unlike most nematocysts, undischarged spirocyst threads bear hollow tubules rather than spines.
(20) The toxins are labile when released from nematocysts and they lose all myotoxic activity within 3 days at 5 degrees C. They can also be isolated chromatographically from crude extracts of the contents of mixed nematocysts of C. fleckeri.