Blastomeres


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Blastomeres

 

cells formed in the process of cleavage of the ovum in multicellular animals. Absence of growth is characteristic of blastomeres, in consequence of which they are diminished by half with each succeeding division (until the formation of the blastula). In the cleavage of holoblastic ova, large blastomeres (macromeres) and small blastomeres (micromeres) are formed with unequal distribution of nutritive substances.

References in periodicals archive ?
In most caridean shrimps, including Crangon crangon, Caridina laevis, Paratya compressa, and Synalpheus minus, radial cleavage is maintained only until the third cell division, when blastomeres rearrange, as shown in Figure 2 (Ishikawa, 1885; Weldon, 1887; Brooks and Herrick, 1891; Nair, 1949).
Division of the blastomere (BL), which is evidence of the fertilization of the oocyte after surgical extraction of follicles from a chicken.
For the second cleavage, the PL extruded from the large blastomere (data not shown).
In addition, this technology requires nuclei fixation which comes with at least two negative consequences: if isolated blastomere does not contain a nucleus or it is damaged during fixation, the lack of genetic material disables analysis, or if there are cytoplasmic residues after fixation, fluorescent signal evaluation will be inappropriate [14].
The pregnancy rates for direct cleavage in more than two blastomeres are described by Athayde Wirka et al.
Aneuploidies of the blastomeres were analyzed according to the depth of the heterozygous SNP alleles.
Soxbl is expressed in the animal hemisphere and the vegetal-anterior blastomeres; Gata.a might activate the expression of Soxb1 in the animal hemisphere, and combinatorial activity of [beta]-catenin and Macho-1/ Zic-r.a might repress the expression of Soxb1 in the vegetal-posterior blastomeres, although this possibility has not yet been experimentally tested.
However, due to the transparency of blastomeres, overlap between blastomeres, and the ambiguity of the images themselves, it is difficult to automatically analyze blastomeres using a single embryo image.
In fact, the Oct-4 is a protein of Pit-Oct-Unc family (5) which is characterized by exclusive expression in blastomeres, in the inner cell mass of the blastocyst, and in the germ cell lineage (6), (7).
Embryo evaluation criteria, A-grade: Embryos with even granulation and well-defined distinct outline, B grade: Embryo with intact but hazy outline having extruded cells and some degenerate blastomere, Degenerated: Embryos with degenerated blastomeres and not possible to determine the exact developmental stage,