What's the difference between isomerism and metamerism?

Isomerism


Definition:

  • (n.) The state, quality, or relation, of two or more isomeric substances.

Example Sentences:

  • (1) Structure assignment of the isomeric immonium ions 5 and 6, generated via FAB from N-isobutyl glycine and N-methyl valine, can be achieved by their collision induced dissociation characteristics.
  • (2) This is interpreted to mean that the release of fructose from the central complex is faster than the isomerization of the E-NADH complex.
  • (3) The optical and oxygen binding properties of the reconstituted myoglobins containing two isomeric monoformyl-monovinylhemins were found to be different.
  • (4) Line broadening detected in several of the high-field nuclear magnetic resonance spectra was attributed to cis-trans isomerization.
  • (5) Two new isomeric delta-lactones 2 and 3 have been isolated from the marine fungus Helicascus kanaloanus (ATCC 18591).
  • (6) Two isomeric hydrolysis products of this compound with only three 3(R)-hydroxymyristic acid moieties attached to the disaccharide-1-phosphate were also identified.
  • (7) Studies on the metabolism of nicotine by rabbit liver microsomal fractions in the presence of 0.01 M sodium cyanide have led to the characterization of two isomeric cyanonicotine compounds.
  • (8) Kinetic methods are outlined for the distinction between two pathways of substrate binding, which include an isomerization either of the free enzyme or of the enzyme-substrate complex.
  • (9) In the case of H101S, a mutant protein with measurable isomerizing activity, substrate binding with novel fluorescent properties was observed, possibly the bound pyranose form of xylose under steady-state conditions.
  • (10) There were consistent isomeric preferences for the R(-) configuration of both DA analogs in stimulating adenylate cyclase (D-1 sites) and in competing for high affinity binding of 3H-spiroperidol (D-2 sites) and of 3H-ADTN (DA agonist binding sites) in striatal tissue, with lesser isomeric differences in the limbic tissue.
  • (11) Oligosaccharides 3 and 4 and oligosaccharides 5 and 6 were isolated as unresolved isomeric mixtures in fractions B3a and B4a, respectively.
  • (12) Subsequent fractionation of the original compound into its two isomeric forms resulted in the identification of the isomer primarily responsible for this convulsive activity.
  • (13) However, the 1500 K simulation produced higher energy structures, even after minimization; in addition, this highest temperature run had many cis-trans peptide isomerizations.
  • (14) From model compound data, it is shown that the expected rate for isomerism is in satisfactory agreement with the rates actually observed for protein folding.
  • (15) Re-analysis of PCP and PCP-Na samples with high PCDD contents on a high-resolution glass capillary column showed the presence of 3 hexa- and the 2 heptachlorodibenzo-p-dioxins with nearly constant isomeric ratios.
  • (16) Such a genomic structure does not appear to have been reported amongst the herpesviruses--all the genomes that do not isomerize either have repeat structures only at the termini, or if present internally, have only direct repeats.
  • (17) The isomeric N,N-dimethyl-4,5-diphenyl-1H-pyrazole-1-propanamine was completely inactive in the primary antidepressant screens.
  • (18) Correspondingly, in the case of the histidine-peptides examined only mixtures of the cyclic isomeric compounds were isolated and structurally characterized by 1H-NMR analysis.
  • (19) In contrast to the biphasic unfolding of the wild-type nuclease, the unfolding of the mutant is represented by a single-phase reaction, indicating that the biphasic unfolding for the wild-type protein is caused by cis-trans isomerization about the prolyl peptide bond in the native state.
  • (20) In order to prepare a completely light-stable rhodopsin, we have synthesized an analog, II, of 11-cis retinal in which isomerization at the C11-C12 cis-double bond is blocked by formation of a cyclohexene ring from the C10 to C13-methyl.

Metamerism


Definition:

  • (n.) The symmetry of a metameric structure; serial symmetry; the state of being made up of metameres.
  • (n.) The state or quality of being metameric; also, the relation or condition of metameric compounds.

Example Sentences:

  • (1) This is especially evident on the ventral surface of the metamerically arranged axial muscles.
  • (2) The sloppy paired locus is involved in the establishment of the metameric body plan of the Drosophila embryo.
  • (3) In Haemopis embryos labeling of both nerve fibers and cell bodies with the antibody appears as expected for a metameric animal in a rostrocaudal temporal gradient from about day 5-6.
  • (4) These six metameres also are responsible for the existence of the pronephros.
  • (5) In each metamere, the area of cell migration takes place near the caudal border of the somite and, from one somite to the other, the number of migrating cells increases in a cephalo-caudal direction.
  • (6) The differences in levels between males and females and between anatomical regions during imaginal life suggest, in this species of cockroach, the physiological importance of the metameric organization in metabolic pathways or functional aspects of biogenic amines.
  • (7) Prior to dorsal closure, expression of the Drosophila gene is observed in non-neuronal tissues, especially in the mesectoderm and presumptive epidermis, both in a metameric pattern.
  • (8) Moreover, such a causative role of cell lineage is suggested by cases where homologous cell types characteristic of a symmetrical and longitudinally metameric body plan arise via homologous cell lineages.
  • (9) The case is characterized by successful counteracting the main clinical manifestations of Raynaud's phenomenon by the local metameric application of cerebrolysin (neuromeric, scleromeric puncturing) employed by the authors for the first time for the disease treatment.
  • (10) In mild contusion of the first-second segments the leading clinical symptoms in the acute period were pareses of the arms and paralyses of hands with retained reflexes and insignificant impairments of sensitivity in fingers, i.e., the level of clinical manifestations did not correspond with the conventional segmento-metameric innervation.
  • (11) A second group of patients had SAs that remained unchanged despite AVM changes (six of seven of these were in patients with metameric angiomatosis).
  • (12) The larval development of P. porosa is characterized by its passing in the cavity of the external cyst, by the complete separation of anlages of the body of the larva and cercomere at the metamere stage and by the intensive growth of the cercomere after the invagination of the larva.
  • (13) Life forms of plants are divided into thirteen types corresponding to the nature of their basic metameres.
  • (14) The invagination process of the metamere is described.
  • (15) This metameric migration pattern is thought to be caused by molecular differences between the rostral and caudal portions of the somite.
  • (16) Identification of specific neuronal populations and their projections in the developing hindbrain reveals a segmental organization in which pairs of metameric epithelial units cooperate to generate the repeating sequence of cranial branchiomotor nerves.
  • (17) In all three organisms, the pattern of engrailed expression at the segmented germ band stage is similar, and the parasegments are the first metameres to form.
  • (18) When neural crest cells were ablated surgically prior to their emigration from the neural tube, the pattern of T-cadherin immunoreactivity was unchanged compared to unoperated embryos, suggesting that the metameric T-cadherin distribution occurs independent of neural crest cell signals.
  • (19) Each nerve is in relation with a column of motoneurons whose both the metameric extension and the exact topography in the anterior horn have been defined.
  • (20) It allows to accurately reach the desired metameric level, avoiding massive sympathetic blockade, and providing a steady hemodynamic condition.

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