What's the difference between blastomere and micromere?
Blastomere
Definition:
(n.) One of the segments first formed by the division of the ovum.
Example Sentences:
(1) Mouse embryos at the two-cell stage were separated into two individual blastomeres, and one blastomere was karyotyped at the second cleavage.
(2) Cleaved embryos with 'ideal' blastomere numbers (2, 4 or 8) showed a considerably higher metaphase frequency than others.
(3) Among the most conspicuous features found were the presence of very distinct desmosome-like structures between blastomeres, and the cytoplasmic cell organelles distribution in three areas referred as: a sub-cortical, a middle and a perinuclear bands.
(4) The procedure involves bisection of single-cell eggs in a medium containing cytochalasin; fusion of egg halves with single blastomeres, induced using Sendai virus or an electrofusion apparatus; and embedding in agar, followed by culture of the reconstituted embryos in the ligated oviducts of ewes in dioestrus.
(5) Lineage tracing techniques demonstrated that those cells in the ICM of early blastocysts which did possess filaments were almost exclusively the progeny of polar 16-cell blastomeres, suggesting that these filaments were directly inherited from outside cells at the 16- to 32-cell transition.
(6) Although the posterior-vegetal blastomeres (B4.1 pair) of the 8-cell embryo have long been believed to be the sole precursors of larval muscle, recent studies using horseradish peroxidase to mark cell lineages have shown that small numbers of muscle cells originate from the anterior-vegetal (A4.1) and posterior-animal (b4.2) blastomeres of this stage.
(7) Day 6 embryos were bisected and the resulting demiembryos were stained with Hoechst 33342 and cell counts were made by counting intact blastomere nuclei.
(8) Embryos developed at a normal rate after destruction of some blastomeres.
(9) The precise temporal and spatial coincidence of the patterns of polarization and the division cycles further suggests that a mechanistic link is maintained among cell division, blastomere polarization, and probably also a heritable component of the animal-vegetal axis.
(10) Each blastomere populated all three primary germ layers.
(11) The effect of destruction of some blastomeres on subsequent cleavage in vitro was investigated in the marsupial Antechinus stuartii.
(12) We conclude that, in general, analysing blastomeres is subject to less mis-diagnosis than polar body analysis, except in the case of dominant diseases which are caused by genes which lie extremely close to the centromere.
(13) The dexiotropic rotations of blastomeres were also observed during the division of the trypsinized zygotes with the tripolar mitotic apparatus.
(14) Primordial germ cells (PGCs), which formed in 78% of cases when the presumptive ventral half to the embryo was cultured, occurred in only 48% of cases when the two ventral vegetal blastomeres were cultured alone.
(15) Nematodes have been considered the chief paradigm for determinate and cell-autonomous development, but recent experiments on the early development of Caenorhabditis elegans suggest that most blastomeres of this nematode are, in fact, determined by interactions.
(16) A fluoresceinated lineage tracer was injected into individual blastomeres of eight-cell sea urchin (Strongylocentrotus purpuratus) embryos, and the location of the progeny of each blastomere was determined in the fully developed pluteus.
(17) Although blastocysts were well expanded, distinct signs of injury to the blastomeres were present, proceeding from loss of complete blastomeres to structural changes such as large lamellar structures, dilation of smooth endoplasmic reticulum and Golgi complexes, and clumping of mitochondria.
(18) The activity of HPRT, but not of APRT, was readily detectable in single 4-cell and 8-cell blastomeres.
(19) The nucleus-like structure was partitioned into blastomeres during cleavage through a process of nuclear fission, and was maintained in a group of extraordinarily large blastomeres until the blastula stage.
(20) To distinguish between these possibilities, we compared the fates of individual frog blastomeres between Li-treated embryos and normal embryos using lineage tracers.
Micromere
Definition:
(n.) One of the smaller cells, or blastomeres, resulting from the complete segmentation of a telolecithal ovum.
Example Sentences:
(1) In Strongylocentrotus droebachiensis, a micromere-specific protein of 133 K molecular weight (MW) was identified.
(2) The most extensively studied example is the specification of the mesodermal stem cell in Lymnaea and Patella, which occurs between 5th and 6th cleavage through an interaction between one macromere and a large number of micromeres.
(3) From the early beginning of the 32-cell stage, all four macromeres introdude far into the interior and tough the centrally radiating cells of the first quartet of micromeres.
(4) We suggest that the fibrillar meshwork is needed for macromere elongation toward the micromeres and that the basal lamina-like layer is involved in the determination process itself.
(5) Ilyanassa obsoleta larvae have two calcium carbonate-containing organs, shell and statocyst, which are derived from five micromere cells (2a, 2c, 2d, 3c, 3d).
(6) During the fifth cleavage interval in equally cleaving embryos, one of the vegetal macromeres makes exclusive contacts with the animal micromeres, and this macromere will give rise to the mesodermal precursor cell at the next division, thereby identifying the dorsal quadrant.
(7) 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.
(8) Caulobothrium longicolle (Linton, 1890) and Phyllobothrium gracile (Weld, 1855) (Cestoda: Tetraphyllidea, Phyllobothriidae) have the same embryonic development with the following characteristic data: --a small number of vitelline cells (2 or 3) pass with the zygote in the ootype;--a non operculate thin egg-shell;--the entire and equal zyhote cleavage following by unequal divisions leading to the formation of four blastomere types (Macromeres, secondary Macromere, Mesomeres and Micromeres);--the differentiation of two syncytial embryonic envelopes during the preoncospheral phase.
(9) To examine competence in this system we have exposed cultured sea urchin micromeres to an inducing medium containing horse serum for various periods of time and have identified a period when micromeres are competent to respond to serum and form spicules.
(10) In Arbacia punctulata, four high molecular weight (HMW) proteins are detected on the surface of isolated micromeres--but not on mesomere-macromere fractions.
(11) Quantitation of immunofluorescence and three-dimensional reconstruction techniques demonstrate that micromere centrosomes differ from macromere centrosomes in two respects: (1) micromere spindle poles contain less centrosomal material than macromere poles, and (2) micromere centrosomes undergo a specific filiform elongation during late anaphase and telophase.
(12) A complementary DNA (cDNA) library was generated from cytoplasmic polyadenylated RNA isolated from differentiated micromere cultures of Strongylocentrotus purpuratus.
(13) Lineages of the first quartet micromeres were followed using Lucifer Yellow dextran as a tracer.
(14) The role of unequal cleavage in echinoid micromere determination was investigated by equalizing the fourth and fifth cleavages with brief surfactant treatment.
(15) We show that in sea urchin embryos, the daughter cells of the small micromeres become part of the coelomic sacs, in contrast to the long-held view that these sacs are purely of macromere origin.
(16) A procedure is described for large-scale isolation of micromeres from 16-cell stage sea urchin embryos.
(17) A method was developed for isolating large quantities of micromeres from the 16-cell stage of the sea urchin, and measurements were made of their ability to incorporate C(14)-L-valine into protein as compared with that of a mixed suspension of micromeres, mesomeres, and macromeres.
(18) Using this method, we fractionated the three different blastomere types of the 16-cell sea urchin embryo, the micromeres, mesomeres, and macromeres, achieving 96, 94, and 96% mean purities, respectively.
(19) Spicule formation of micromere-derived cells was enhanced by anti-FAPS.
(20) pHPSMC mRNA was detected in micromeres in vitro after 48 h of culture, but it was not found in blastomeres immediately after isolation.