(n.) The indirect division of cells in which, prior to division of the cell protoplasm, complicated changes take place in the nucleus, attended with movement of the nuclear fibrils; -- opposed to karyostenosis. The nucleus becomes enlarged and convoluted, and finally the threads are separated into two groups which ultimately become disconnected and constitute the daughter nuclei. Called also mitosis. See Cell development, under Cell.
Example Sentences:
(1) These results indicate a hierarchy of requirements for high pHi during early development of sea urchin embryos, with protein synthesis, karyokinesis, and cytokinesis showing, respectively, increasing requirements for an elevated pHi.
(2) Since we found that PMA-mediated formation of binuclearity was not the effect of cell fusions, it was assumed that the inhibition of cytokinesis preceded by karyokinesis was responsible for binuclearity.
(3) Plant cytokinesis in a particular orientation and location can be viewed as having several component stages, often beginning with the establishment of division polarity before karyokinesis occurs.
(4) We have found that nocodazole reversibly inhibits nuclear migration and can be used to induce karyokinesis before the completion of nuclear migration, resulting in spindles that are displaced toward the hypothecal end of the cell.
(5) Double nucleated cells occur in hypertrophying cells by karyokinesis without subsequent cytokinesis, perhaps in response to the intense protein synthetic demands of normal growth.
(6) The spindle had a broad polar region and did not commence karyokinesis in the first maturation division.
(7) With respect to karyokinesis, mitotic apparatus (MA) structure often was altered when the PI cycle was blocked, and anaphase was blocked when the PI cycle was blocked.
(8) These concentrations of cytochalasin B blocked cytokinesis but not karyokinesis with the result that cells became multinucleate after mitoses.
(9) Despite the ability for karyokinesis, it is concluded that astrocytes do undergo changes with ageing.
(10) These calmodulin-binding proteins may be involved in regulating microtubule organization and depolymerization during karyokinesis.
(11) The spleen was swollen, and the corpuscles and karyokinesis of the cell decreased.
(12) Chromosomes finally entered one blastomere, although they did not participate in the following karyokinesis.
(13) Karyokinesis proceeds to completion under a low pHi, but is retarded, while cytokinesis is always impaired.
(14) We conclude that the mechanism of giant cell DNA amplification involves multiple rounds of DNA replication in the absence of both karyokinesis and cytokinesis, and that sister chromatids, but not homologous chromosomes, remain closely associated during this process.
(15) Similar changes are visible in the contralateral testis which also demonstrates the evolution of multinucleate spermatids by karyokinesis without cytokinesis.
(16) During karyokinesis the nucleolus remained present and divided to form polar masses.
(17) Apparently, the parasite had genetically altered a metabolic pathway necessary for both the initiation of DNA replication and karyokinesis.
(18) Our results would also suggest that activation of gene expression is simply related to neither cell number nor time spent in culture since fertilization, but may be related to continuing karyokinesis.
(19) It starts with synthesis of the new MP a few minutes upon karyokinesis has been completed.
(20) The same dichotomy between the levels of the two decarboxylases was observed for meningiomas, in which ODC levels were higher in atypical forms (with karyokinesis) then in typical forms (without karyokinesis).
Mitosis
Definition:
(n.) See Karyokinesis.
Example Sentences:
(1) MAF-G activity was inhibited by mitomycin C and colchicine, which inhibit DNA synthesis and mitosis, respectively, but not by 2-deoxy-D-glucose, an inhibitor of glucose metabolism.
(2) With the stimulated liver being irradiated, the number of cells synthetizing DNA and entering into mitosis was seen reduced almost twice, whereas DNA synthesis and entering into mitosis were delayed, resp., by 4 and 6 hours.
(3) The distribution of cells at the stage of DNA synthesis and mitosis in all the parietal peritoneum speaks of the absence of special proliferation zones.
(4) Isoproterenol [IC 50 approximately 1 X 10(-9) M], prostaglandins, dibutyryl cyclic AMP [IC 50 approximately 2 X 10(-5) M], papaverine, theophylline and 5' AMP were inhibitory in the assay, whereas dibutyryl cyclic GMP and the cholinergic stimulator carbamylcholine either stimulated or had no effect on mitosis.
(5) Despite severe defects in the 1st or 2nd meiotic spindles in all mutants, no effect on mitosis was observed.
(6) Since transcription does not take place during mitosis, the amount of protooncogene products is rapidly decreased (they are extremely unstable).
(7) The role played by macrophages in two effects of lipopolysaccharide (LPS) on the immune system of the mouse-substitution for helper T cells and induction of B-cell mitosis-has been investigated.
(8) The results obtained allow to conclude that heterophasic condition of the fused cells is one of the causes of pathological mitosis of polykaryons and of their death.
(9) The effect of intracerebroventricular injection of the mitosis inhibitor colchicine on expression of mRNA for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 was studied in the rat brain with in situ hybridization.
(10) The major events of mitosis have traditionally been considered to represent two distinct pathways and have been studied by two separate groups of workers.
(11) The V79 cells were treated for 30 min and in general, loss of a stainable spindle could be demonstrated at slightly higher concentrations than c-mitosis.
(12) However, unlike animal cell calmodulin, endosperm calmodulin appears to associate with kinetochore microtubules throughout mitosis, which suggests a specialized role for higher plant calmodulin in the regulation of kinetochore microtubule dynamics.
(13) This finding is directly opposed to that in rat skin where mitosis is stimulated.
(14) The restriction enzymes were introduced by electroporation into exponentially growing cells during the second replication cycle in bromodeoxyuridine, and SCEs were analyzed at mitosis.
(15) The absence of these mRNAs in mitosis and their disappearance at 4 hr and later in meiosis suggest that the rec7 and rec8 gene products may be involved primarily in the early steps of meiotic recombination in S. pombe.
(16) The distribution of bone marrow cells within the cell cycle was determined by flow microfluorometry and 7 hours after treatment with vincristine consisted of 69% in G1, 21% in S, and 9% in mitosis.
(17) In contrast, in HeLa, a human epithelial cell, keratin-containing IFB appear to dissemble as cells enter mitosis (Franke, W. W., E. Schmid, C. Grund, and B. Geiger, 1982, Cell, 30:103-113).
(18) After administration of vinblastine, a drug blocking mitosis in metaphasis, the percentage of lymphoblasts decreases whereas the percentage of X cells increases.
(19) The ultrastructure study, done before the 19th week ("pretumor" phase) confirms some previous observations (increase in the zone of mitosis, secretory changes, mutation producing effects).
(20) Still, they gave valuable information in relation to environmental screening; thus, the finding of c-mitosis may indicate risks of aneuploidy.