What's the difference between aster and ester?

Aster


Definition:

  • (n.) A genus of herbs with compound white or bluish flowers; starwort; Michaelmas daisy.
  • (n.) A plant of the genus Callistephus. Many varieties (called China asters, German asters, etc.) are cultivated for their handsome compound flowers.

Example Sentences:

  • (1) Microscopic examinations of eggs stained with aceto-orcein or the DNA fluorochrome bisbenzimide and direct observations on isolated sperm aster complexes show that halothane induces polyspermy (multiple sperm entry) when present at fertilization.
  • (2) Second, the bulk of the vegetally located myoplasm moves with the sperm aster towards the future posterior pole, but interestingly about 20% remains behind at the anterior side of the embryo.
  • (3) The CTR2611 antigen is present in the center of each of these asters.
  • (4) Cytoplasmic asters were observed at all doses tested.
  • (5) RNase alters the in vitro assembly of spindle asters in homogenates of meiotically dividing surf clam (Spisula solidissima) oocytes.
  • (6) ASTER is an integration of the ACQUIRE (AQUatic toxicity Information REtrieval system) and QSAR (Quantitative Structure Activity Relationships) systems.
  • (7) The data indicate that meiotic spindle assembly is dependent on ongoing protein synthesis in the cumulus-enclosed hamster oocyte; in contrast, chromatin condensation and aster formation are not as sensitive to protein synthesis inhibitors during meiotic resumption.
  • (8) The eggs of the surf clam Spisula solidissima were artificially activated, homogenized at various times in cold 0.5 M MES buffer, 1mM EGTA at pH 6.5, and microtubule polymerization was induced by raising the temperature to 28 degrees C. In homogenates of unactivated eggs few microtubules form and no asters are observed.
  • (9) 101:289-316) used computer simulations to show that long-range signals from the asters, varying inversely as various powers of distance, produce summed effects that are minima at the equator of spherical cells.
  • (10) Microinjection of SPN-3 antibody into taxol-treated mitotic PtK2 cells causes disruption of the asters as judged by tubulin staining of the same cells.
  • (11) Furthermore, numerous cytoplasmic asters become visible in the cytoplasm.
  • (12) This is accompanied by the apparent shortening of the microtubules running between the asters.
  • (13) Mesomere-mesomeres (which divide equally) and macromere-micromeres (which divide unequally) are compared in terms of their asters (both mitotic and so-called interphase asters), spindle apparatus, and contractile ring.
  • (14) Within 15 min after incubation in D2O, numerous fine centrosomal foci are detected, and they organize a connected network of numerous asters which fill the entire egg.
  • (15) In the normal two-celled embryos of various pulmonate molluscs, the orientation of spindles characteristic of metaanaphase is being frequently established gradually, in the process of transition from pro- to metaphase accompained by the growth of spindle and asters.
  • (16) Colcemid-treated prometaphase cells lysed into polymerization-competent tubulin develop large asters in the region of the centrioles and short tubules at kinetochores, making it unlikely that all microtubule formation in lysed cell preparations is dependent on tubulin addition to short tubule fragments.
  • (17) They located in euchromatin regions of thymus lymphocytes, with a characteristic aster-like immunofluorescence pattern, and on the border of condensed chromatin areas by deposition of immunogold particles in ultrathin sections of thymus.
  • (18) We conclude first, that centrioles contain RNA which is required for initiation of aster formation, and second, that the centriole activity or ability to assemble a mitotic aster is separable from the basal body activity, or ability to serve directly as a template for microtubule growth.
  • (19) When injected into fertilized eggs at streak stage, the tubulin was quickly incorporated into each central region of growing asters.
  • (20) The asters then divide to form a transient tetrapolar figure.

Ester


Definition:

  • (n.) An ethereal salt, or compound ether, consisting of an organic radical united with the residue of any oxygen acid, organic or inorganic; thus the natural fats are esters of glycerin and the fatty acids, oleic, etc.

Example Sentences:

  • (1) These effects are similar to those reported for AVP and phorbol esters, activators of protein kinase C. Forskolin and isoproterenol, which induce cAMP accumulation, activated extractable topoisomerase II (maximum 5-15 min after treatment), but not topoisomerase I. Permeable cyclic nucleotide analogs dBcAMP and 8BrcGMP selectively activated extractable topoisomerase II and topoisomerase I activities, respectively.
  • (2) Preincubation of human neutrophils with recombinant tumor necrosis factor alpha has previously been shown by us to enhance superoxide production of neutrophils in response to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine, and the phorbol ester, phorbol myristate acetate.
  • (3) Tumor promoting phorbol esters (1-1000 nM) could also inhibit PGE2 stimulated cAMP production dose dependently.
  • (4) These products were identified to be epimers of 5,12(S)-dihydroxy-eicosatetraenoic acid methyl ester (5,12(S)-diHETE-Me) and epimers of 11,12-diHETE-Me.
  • (5) Benzyloxycarbonylarginine p-nitrophenyl ester and other activated esters of N-a-sustituted arginine salts may be useful reagents for introduction of trypsin-labile protecting groups into peptide fragments for purpose of polypeptide semi-synthesis.
  • (6) The immunodetectable PKC level in hypothyroid liver was elevated 7.7-fold, whereas the phorbol-ester binding capacity and the immunodetectable alpha-PKC level were increased 2.4- and 2.6-fold, respectively.
  • (7) The presence of a previously unreported dipeptide transport mechanism within blood leukocytes and the selective enrichment of the granule enzyme, DPPI, within cytotoxic effector cells of lymphoid or myeloid lineage appear to afford a unique mechanism for the targeting of immunotherapeutic reagents composed of simple dipeptide esters or amides.
  • (8) Incubation of membrane with DL-Hcys alone (5 X 10(-5) M), the combination of both Ad (5 X 10(-5)) and DL-Hcys (5 X 10(-5)), or S-adenosyl-L-homocysteine (SAH) (1 X 10(-6)) strongly decreased the methyl ester formation.
  • (9) To this purpose, the formation of DHT has been measured in rat glial cell cultures after different time of exposure to TPA, 4 alpha-Ph, an active and an inactive phorbol ester respectively, and 8-Br-cAMP.
  • (10) Insulin incubation of plasma membranes pretreated with protease inhibitors (leupeptin, phenylmethylsulfonylfluoride) or with exogenous trypsin, but not chymotrypsin substrates (esters of arginine and tyrosine) yields an inactive supernatant on PDH.
  • (11) Lymphocyte stimulation by phorbol ester for a short time induces c-fos and c-myc expression, but has no effect on [3H]thymidine incorporation.
  • (12) The cryptoxanthin esters varied from 5 to 10% of the total carotenoids in Valencia orange juice concentrates and from 10 to 15% of the total carotenoids in Navel orange juice concentrates.
  • (13) Early in the regression process, cholesterol esters are reduced at least partly by hydrolysis to yield cholesterol, some of which may crystallize and inhibit rapid regression.
  • (14) The kinetics of the luminescent signal with the different luciferin esters varied significantly, indicating possible differences in the rates of uptake, breakdown and enzyme inhibition.
  • (15) In comparison to rat pancreas, [D-Phe6]BN-(6-13)ethyl ester, Ac-GRP-(20-26)ethyl ester, [D-Phe6,Cpa14, psi 13-14]BN-(6-14), [Leu14, psi 13-14]BN, and [Leu14, psi 9,10]BN had a 10,000-, 2,940-, 1,425-, 122-, and 4-fold, respectively, weaker affinity for BN receptors.
  • (16) Enzymatic lability does not, however, play as important a role as lipophilicity in the corneal and conjunctival penetration of cycloalkyl and aryl ester prodrugs.
  • (17) To determine whether the triadimefon-induced hyperactivity is due to an action on CNS catecholaminergic systems, we evaluated the effects of combined treatment of triadimefon with either the tyrosine hydroxylase inhibitor d,l-alpha-methyl-p-tyrosine methyl ester HCl (alpha MPT) or the amine depletor reserpine.
  • (18) Growth of C. albicans in the presence of AGE affected the yeast lipid in a number of ways: the total lipid content was decreased; garlic-grown yeasts had a higher level of phosphatidylserines and a lower level of phosphatidylcholines; in addition to free sterols and sterol esters, C. albicans accumulated esterified steryl glycosides; the concentration of palmitic acid (16:0) and oleic acid (18:1) increased and that of linoleic acid (18:2) and linolenic acid (18:3) decreased.
  • (19) In comparison with native counterparts, the in vitro-formed LDL2 and HDL + VHDL were characterized by lower levels of triglyceride and cholesterol ester and higher levels of free cholesterol and lipid phosphorus.
  • (20) Several histidine derivatives are not susceptible to the enzyme but do inhibit the enzyme activity competitively; the most effective inhibitors are L-histidine methyl ester (Ki = 3.66 mM) and beta-imidazole lactic acid (Ki = 3.84 mM).