(n.) A kernel; hence, a central mass or point about which matter is gathered, or to which accretion is made; the central or material portion; -- used both literally and figuratively.
(n.) The body or the head of a comet.
(n.) An incipient ovule of soft cellular tissue.
(n.) A whole seed, as contained within the seed coats.
(n.) A body, usually spheroidal, in a cell or a protozoan, distinguished from the surrounding protoplasm by a difference in refrangibility and in behavior towards chemical reagents. It is more or less protoplasmic, and consists of a clear fluid (achromatin) through which extends a network of fibers (chromatin) in which may be suspended a second rounded body, the nucleolus (see Nucleoplasm). See Cell division, under Division.
(n.) The tip, or earliest part, of a univalve or bivalve shell.
(n.) The central part around which additional growths are added, as of an operculum.
(n.) A visceral mass, containing the stomach and other organs, in Tunicata and some mollusks.
Example Sentences:
(1) Microionophoretically applied excitatory amino acids induced firing of extracellularly recorded single units in a tissue slice preparation of the mouse cochlear nucleus, and the similarly applied antagonist 2-amino-5-phosphonovalerate (2APV) was demonstrated to be a selective N-methyl-D-aspartate (NMDA) receptor antagonist.
(2) The present results provide no evidence for a clear morphological substrate for electrotonic transmission in the somatic efferent portion of the primate oculomotor nucleus.
(3) In the caudal spinal trigeminal nucleus (Vc), the collaterals of one half of the periodontium afferent fibers terminated mainly in lamina V at the rostral and middle levels of Vc.
(4) It is concluded that in the mouse model the ability of buspirone to reduce the aversive response to a brightly illuminated area may reflect an anxiolytic action, that the dorsal raphe nucleus may be an important locus of action, and that the effects of buspirone may reflect an interaction at 5-hydroxytryptamine receptors.
(5) hypoglossal nucleus), whereas in other areas the angiotensinogen gene was expressed only in a certain population of glial cells.
(6) Local application of 8-OH-DPAT (0-5 micrograms) into the median raphe nucleus, facilitated male rat sexual behavior, as evidenced by a decrease in number of intromissions preceding ejaculation and in time to ejaculation.
(7) In addition, lightly immunostained cells were distinguished in the caudal portion of the hypothalamic arcuate nucleus, area of tuber cinereum, retrochiasmatic area, and rostral portion of the paraventricular thalamic nucleus after colchicine treatment.
(8) Arising of the nucleus from a polyheteronomous nucleoid of proeukaryotes.
(9) It is possible that the IgE that linked abnormally with the propofol had specific binding sites for the phenyl nucleus and the isopropyl groups, which are present in propofol and many other drugs.
(10) We conclude that neuronal activities in the region of the retrofacial nucleus are important both in the integration of stimuli from the central chemoreceptors and in defining the discharge patterns of respiratory neurons.
(11) A 68 year-old man with a history of right thalamic hemorrhage demonstrated radiologically in the pulvinar and posterior portion of the dorsomedian nucleus developed a clinical picture of severe physical sequelae associated with major affective, behavioral and psychic disorders.
(12) While the heaviest anterogradely labeled ascending projections were observed to the contralateral ventral posterolateral nucleus of the thalamus, pars oralis (VPLo), efferent projections were also observed to the contralateral ventrolateral thalamic nucleus (VLc) and central lateral (CL) nucleus of the thalamic intralaminar complex, magnocellular (and to a lesser extent parvicellular) red nucleus, nucleus of Darkschewitsch, zona incerta, nucleus of the posterior commissure, lateral intermediate layer and deep layer of the superior colliculus, dorsolateral periaqueductal gray, contralateral nucleus reticularis tegmenti pontis and basilar pontine nuclei (especially dorsal and peduncular), and dorsal (DAO) and medial (MAO) accessory olivary nuclei, ipsilateral lateral (external) cuneate nucleus (LCN) and lateral reticular nucleus (LRN), and to a lesser extent the caudal medial vestibular nucleus (MVN) and caudal nucleus prepositus hypoglossi (NPH), and dorsal medullary raphe.
(13) In contrast to this, adrenalectomy decreased ANP levels markedly in the organum vasculosum laminae terminalis and preoptic periventricular nucleus, which are reportedly involved in the central regulation of salt and water homeostasis.
(14) The shape of the nucleus changes from ovoid to a distinctive, radially splayed lobulated structure.
(15) Immunocytochemical analysis also suggested that bFGF immunoreactivity was present in the nucleus as well as the cytoplasm of astrocytes and CA2 neurons.
(16) The effect of Y-516 on the hyperactivity induced by dopamine injected bilaterally into the nucleus accumbens was compared with those of clocapramine (CCP), haloperidol (HPD) and chlorpromazine (CPZ).
(17) Moderately differentiated tumor revealed a wider range of nucleus size, less clustering (coefficient--3.59) and more hyperchromatic (70.1%) and "bare" (49.4%) nuclei and large nucleoli (22.2%).
(18) The majority of intensively stained and densely packed cells have been observed in tv nucleus.
(19) Following electrical stimulation of the hypothalamic paraventricular nucleus (PVN) area, 21% of the neurons were orthodromically excited, 6% were inhibited and 2.5% were antidromically activated.
(20) Proenkephalin A-related immunoreactive neuronal perikarya were detected in the central gray, reticular formation, nucleus raphes, trapezoid body, nucleus parabrachialis lateralis and medialis, nucleus spinalis nervi trigemini, nucleus dorsalis nervi vagi, and in the nucleus tractus solitarii.
Pronucleus
Definition:
(n.) One of the two bodies or nuclei (called male and female pronuclei) which unite to form the first segmentation nucleus of an impregnated ovum.
Example Sentences:
(1) In the triploids, the 40 female chromosomes present (mouse, n = 20) were derived from a single diploid pronucleus formed after the extrusion of a first polar body, and following the monospermic fertilization of primary oocytes.
(2) Both nucleate and anucleate fragments lose the capability of transforming sperm nucleus into fully formed pronucleus sometime between 3 and 5 h after activation.
(3) A series of transgenic mice was produced by microinjection of a segment of DNA, containing 460 base pairs of the phosphoenolpyruvate (P-enolpyruvate) carboxykinase promoter-regulatory region ligated to the bovine growth hormone structural gene, into the male pronucleus of fertilized mouse eggs.
(4) Retrievals in which one or more oocytes exhibited one pronucleus were compared with retrievals in which no one-pronuclear oocytes (control) were observed.
(5) Strengthening of lethal and cytogenetic effects was only observed in case when embryos were placed in the caffeine solution, prior to onset of the first DNA replication in the male pronucleus.
(6) During the course of the formation of the male pronucleus, the subacrosomal rod and tail become detached from the head and disintegrate.
(7) Following transvaginal sonographic oocyte retrieval in vitro fertilization is performed and the fertilized (pronucleus-stage) or embryos are transferred into the tube by laparoscopy.
(8) When the drug is removed 3 h after insemination, the meiotic spindle(s) is reconstructed, the second polar body(ies) is extruded, and a female pronucleus (or micronuclei) forms.
(9) Evaluation of data concerning DNA amounts, heterochromatin contents, distribution of breaks, repair capacities in two-break sites and oxygen concentrations in mature spermatozoa revealed no contradiction to the hypothesis that the greater sensitivity of Phryne cincta is mainly due to a high degree of spiralization of the paternal pronucleus chromosomes.
(10) This conditioned medium was alone able to affect sperm penetration and male pronucleus formation in cumulus oocytes, but it did not exert any influence on denuded oocytes.
(11) Sperm centrioles were also closely associated with the male pronucleus (16-20 hr after insemination) in pronuclear stage embryos.
(12) Microtubules of unknown origin are associated with the sperm pronucleus during its migration.
(13) Correction of polyspermy through pronucleus extraction in the absence of membrane relaxants was applied to 25 polyspermic human zygotes.
(14) On the other hand, in the fully mature oocytes, which were activated by sperm penetration, the sperm nucleus was transformed into the male pronucleus.
(15) From the nine eggs used in this experiment one egg developed a pronucleus and one egg developed to a four-cell stage.
(16) Mature sperm have neither detectable centrosomes nor detectable kinetochores, and shortly after sperm incorporation kinetochores become detectable in the decondensing male pronucleus.
(17) 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.
(18) This centrosome is attached to the centrosomal fossa, a bowl-shaped depression of the nuclear envelope of the male pronucleus.
(19) One per cent displayed a single pronucleus, and haploid chromosome complements were found in the corresponding cleaved embryos which were considered to be parthenotes.
(20) Studying the haploid portion of the male pronucleus using the hamster test reflects the process of meiosis.