(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.
Egg
Definition:
(n.) The oval or roundish body laid by domestic poultry and other birds, tortoises, etc. It consists of a yolk, usually surrounded by the "white" or albumen, and inclosed in a shell or strong membrane.
(n.) A simple cell, from the development of which the young of animals are formed; ovum; germ cell.
(n.) Anything resembling an egg in form.
(v. t.) To urge on; to instigate; to incite/
Example Sentences:
(1) Here we report that sperm from psr males fertilizes eggs, but that the paternal chromosomes are subsequently condensed into a chromatin mass before the first mitotic division of the egg and do not participate in further divisions.
(2) We similarly evaluated the ability of other phospholipids to form stable foam at various concentrations and ethanol volume fractions and found: bovine brain sphingomyelin greater than dipalmitoyl 3-sn-phosphatidylcholine greater than egg sphingomyelin greater than egg lecithin greater than phosphatidylglycerol.
(3) Whether hen's egg yolk can be used as a sperm motility stimulant in the treatment of such conditions as asthenospermia and oligospermia is subjected for further study.
(4) Increasing concentrations of cholesterol monotonically increase the dipole potential of egg phosphatidylcholine monolayers, from 415 mV with no cholesterol to 493 mV with equimolar cholesterol.
(5) The percentage of eggs clamped at values more negative than -65 mV, which responded at insemination by developing an If, decreased and dropped to 0 at -80 mV.
(6) Lead levels in contents and shells of eggs laid by hens dosed with all-lead shot were about twice those in eggs laid by hens dosed with lead-iron shot.
(7) Saturated acyl residues predominated in lysolecithin and unsaturated ones in acids released by hydrolysis of egg lecithin.
(8) By 30 min after insemination, the surface of the egg is relatively smooth.
(9) With both approaches, carbohydrate and fat had little influence whereas egg albumin had a significant inhibitory effect on the absorption of nonheme iron.
(10) Larvae from fresh water eggs, cultured in fresh water and 'normal' laboratory cultures reached 50% infectivity in 3-5 days, losing potential infectivity in 11-15 days post-hatching.
(11) Plakoglobin is present in the fertilized egg, increases in abundance by neurula stage, then declines at the tailbud and tadpole stages.
(12) Fertilization of golden hamster eggs was blocked both in vitro and in vivo by antibodies produced in rabbits against specific hamster ovarian antigens (HOA).
(13) Multiple spawnings of individual females were also observed during the spawning period affecting the relative fecundity of the eggs.
(14) The faeces of forty-two were examined microscopically for nematode eggs.
(15) In Experiment 1 (summer), hens regained body weight more rapidly, returned to production faster, and had larger egg weights (Weeks 1 to 4) when fed the 16 or 13% CP molt diets than when fed the 10% CP molt diet.
(16) The time of sperm penetration in the mouse eggs, however, was delayed for one-half to one hour when ejaculated sperm were used.
(17) Polypeptides of egg-borne Sendai virus (egg Sendai), which is biologically active on the basis of criteria of the infectivity for L cells and of hemolytic and cell fusion activities, were compared by polyacrylamide gel electrophoresis with those of L cell-borne (L Sendai) and HeLa cell-borne Sendai (HeLa Sendai) viruses, which are judged biologically inactive by the above criteria.
(18) The pattern of day to day variability in egg counts from individuals can be characterized by the linear relationship between the logarithms of the variances and means.
(19) Rhabdomeres are substantially smaller and visual pigment is nearly eliminated when Drosophila are carotenoid-deprived from egg to adult.
(20) In conclusion, the main finding of the present investigation, based on the development of ME fragments comprising 40-50% of the total egg volume, is that ascidian embryos are capable of regulative development.