(1) The fertilization reaction of echinoderm eggs (Lytechinus pictus, a sea urchin, and Dendraster excentricus, a sand dollar) was followed with intracellular electrodes.
(2) I describe the anatomy and fine structure of the echinoderm ovary, with emphasis on both the cellular relationships of the germ line cells to the somatic cells of the inner epithelium, and on the neuromuscular systems.
(3) In echinoderms, which stop at interphase, no such a factor has so far been found.
(4) In frogs and mammals, the oocytes are arrested at the second metaphase of meiosis whereas in echinoderms they are blocked later, at the pronucleus stage.
(5) An examination of Antp class homeo box genes in deuterostomes indicates that a chromosomal duplication has taken place in the evolutionary line leading to the vertebrates after the divergence of the echinoderms.
(6) Next, we present some features of the described processes for sugar and amino acid transport in the tubular portion of gastrointestinal tracts of three major invertebrate groups: echinoderms, molluscs, and arthropods.
(7) The emonctory structures, functions and stereotype and their component parts are studied in protists, spongia, coelenterata and coelomata: lower worms, annelids, their hyponeurian descendents (arthropods, molluses) and epineurian descedents echinoderms and protochordates (Stomochordata, Tunicata, Cephalochordata).
(8) The transition from the single creatine kinase locus, characteristic of certain echinoderms, to the two creatine kinase loci which are orthologous to those present in all vertebrates, occurred early in the chordate line.
(9) These features are characteristic of sea urchin (Echinoderm) spines which are composed of ornately formed calcite crystals covered by an epithelium.
(10) The echinoderms Asterias rubens and Solaster papposus (Class Asteroidea) metabolize injected [4(-14)C]cholest-5-en-3beta-ol to produce labelled 5alpha-cholestan-3beta-ol and 5alpha-cholest-7-en-3beta-ol.
(11) Echinoderm oocyte maturation is reviewed and a description of the ultrastructural, biochemical and molecular biological changes thought to occur during this process is presented.
(12) Another round of gene duplication, involving Wnt-3, -5, -7, and -10, occurred after the echinoderm lineage arose, on the ancestral lineage of jawed vertebrates.
(13) Changes in the distribution and organizational state of actin in the cortex of echinoderm eggs are believed to be important events following fertilization.
(14) Small numbers are present in algae, ferns, conifers, sponges, echinoderms, other marine animals, and arthropods.
(15) However, recent work which used colchicine to block microtubule assembly in the eggs of two other echinoderms, S. purpuratus and D. excentricus, has raised serious questions about the generality of this role for spindle microtubules.
(16) It would seem that these epitope regions have been strongly conserved since the epitope region is also present in the phosphoprotein of echinoderm teeth.
(17) Both species differences and species similarities in the agglutination were found in spermatozoa of the echinoderm, the sea urchin and the starfish.
(18) Furthermore, during meiotic maturation in these echinoderm and amphibian oocytes, this is followed by activation of many of the same protein-serine (threonine) kinases that are stimulated when quiescent mammalian somatic cells are prompted with mitogens to traverse from G0 to G1 phase.
(19) One of these fragments contains the active site and is identical at all sequenced residues with the corresponding region from the echinoderm sperm flagellar creatine kinase, and is 96% homologous with both chicken and rat B creatine kinase subunits.
(20) A significant feature of the early development of fertilized echinoderm and amphibian eggs and germinating seed embryos is the utilization of genetic information that has been previously transcribed during oogenesis and seed ripening.
Ossicle
Definition:
(n.) A little bone; as, the auditory ossicles in the tympanum of the ear.
(n.) One of numerous small calcareous structures forming the skeleton of certain echinoderms, as the starfishes.
Example Sentences:
(1) The second, the normal tubercle for insertion of the transverse ligament of the atlas, may look like a separate ossicle or a chip fracture.
(2) Each mastoid and epitympanum was extensively involved with chronically inflamed tissue which surrounded the ossicles and chorda tympani nerve.
(3) A case is presented in which an ossicle was evaluated acutely.
(4) A review of arthroscopic, radiographic, and clinical data of all patients undergoing ankle arthroscopy at our center provided the following diagnoses: talar dome osteochondral fractures, loose bodies, accessory ossicles, talar dome cyst with loose bodies, and chronic synovitis.
(5) Tomography of the petrous bones showed, in both cases, an upward tilt of the long axes of the bones including their auditory canals, generalized sclerosis of the petrous pyramids and enlargement of the ossicles.
(6) X-ray powder diagrams of normal ossicles were shown as a granular hydroxyapatite.
(7) There was a profound reduction in the ability of marrow to generate ossicles when transplanted under the kidney capsule as a result of the administration of either 224Ra or 239Pu, with only transient recoveries from the effects of 239Pu at 4 days and at 3 months after injection.
(8) The position, displacement and phase angle of the rotation axis of the ossicles was calculated based on the displacement and phase angle of the umbo, malleus head and lenticular process.
(9) Ossicular mobility was assessed by direct coupling of a piezoelectric ceramic vibrator to the ossicles during middle ear surgery.
(10) Increase in size of the auditory ossicles was stated to occur unevenly, every bone having certain periods of the most intensive growth.
(11) This restricted distribution of tenascin may be important in the morphogenesis of scleral papillae and scleral ossicles.
(12) Particular care should be taken with those who have both atlantoaxial instability and odontoid hypoplasia or accessory ossicles as they are at particular risk of spinal cord damage.
(13) The valve ossicle resembles that of Parechinus in its triangular valve shape and open blade form, contrasting with Echinus in these features.
(14) The ossicles were nearly always present but deformed.
(15) Two cases of ossicles in human menisci are added to the list of 18 previously reported cases.
(16) In the treatment of the various malformations of the external and middle ear (atresia of the bony canal, malformed ossicles, reduced volume of the middle ear in varying degrees, atypical course of the facial nerve), the indirect approach to the middle ear via the antrum appears to be the safest operative procedure for a tympanoplasty in cases of congenital atresia.
(17) The purpose of this study is to investigate the differences in the destruction of ossicles in chronic ear disease caused solely (monoinfection) by one of the most common three bacteria, namely Staphylococcus aureus, Pseudomonas aeruginosa or Proteus strain.
(18) We present four patients with meniscal ossicles associated with a longitudinal tear of the medial meniscus.
(19) They recorded an auditory gain in more than half the patients (early: PORP 97%, TORP 73%, piston 52%; plasty transplants of ossicles obtained from subjects who died accidentallyĕ For preserfic Council of the Ministry of Health, Czech Socialist Republic, recommended, based on the clinical tests, the manufacture of silastic prostheses of the middle ear.
(20) A hypothesis is developed to the effect that the movement of the ossicles, necessary for lubrification and nutrition of the hyaline cartilage, is maintained by the two middle-ear muscles.