The separation of the blood cells of Styela rustica (Styelidae, Stolidobranchiae) in discontinuous Percoll gradient showed 4 fractions. The 4th and bottom most fraction contained 90-100% of morula cells. The protein composition of the morula cell fraction revealed on SDS-PAGE showed two major proteins with m.w. 47 and 26 kDa. These proteins were heavily positively charged. Polyclonal antiserums...

Background “Inside-Outside” hypothesis Cells located on the inside of the 16-cell morula differentiate into the inner cell mass (ICM) of the blastocyst while cells on the outside of the morula differentiate into the trophectoderm (TE) If a cell were moved to a different location in the morula, it would differentiate into a different kind of cell Hypothesis and corollary assumed that, for a time...

Background: Transgenic mice are being considered as invaluable tool in biological sciences towards comprehension of the cause of the genetic diseases. Manipulated embryonic stem (ES) cells are used to produce loss-of-function mutant mice. Microinjection of manipulated ES cells into blastocoel cavity, and morula fusion are the two main techniques in producing transgenic mice. So...

As a first step to understand preimplantation development, we performed global gene-expression profiling of morula and blastocyst using the NIA 15k mouse cDNA microarray. Gene expression levels were measured four times for blastocyst and five times for morula. Student's t-test at the 5% significance level identified 428 genes upregulated and 748 downregulated in blastocyst compared to morula. T...

The membrane potential in the blastomeres of dividing Triturus egg cells increases progressively from the first cleavage to the late morula stages. Both the animal and vegetal poles show the same increasing trend in potential; there is no significant potential difference between them. Upon first cell cleavage, the total resistance of the egg cell surface in contact with the exterior decreases t...

There were no significant differences in the distribution of embryos reaching to 2cells, 4cells, morula or blastocysts culturing on human endometrial stromal cells (Secretory or proliferative phases). The percent of morula in stage A (without fragmentation), stage B (<25% fragmentation), stage C (25-50% fragmentation) and stage D (>50% fragmentation) and did not showed significant differences b...

Embryos of certain inbred mouse strains, and their F1 hybrids, are able to develop from the 1-cell to blastocyst stage in simple chemically defined media containing lactate (L), pyruvate (P) and glucose (G). The individual roles of these substrates in supporting complete preimplantation development in vitro was examined with 1-cell F2 embryos from B6CBF1 hybrid mice. Embryos collected between 2...