Eggs of the sea urchin, Arbacia punctulata, treated with 3% urethane for 30 sec followed by 0.3% urethane and inseminated are polyspermic and fail to undergo a typical cortical reaction. Upon insemination the vitelline layer of urethane-treated eggs either does not separate or is raised only a short distance from the oolemma. 1-6 min after insemination, almost all of the cortical granules remai...

When mating type plus and minus gametes of Chlamydomonas are mixed, they agglutinate with each other via their flagella, fuse, then initiate the zygote formation program which includes synthesis of the zygote cell wall, fusion of nuclei and chloroplasts, and the digestion of chloroplast DNA from the minus parent. The mRNAs from gamete and zygote cells was isolated and hybridized to cDNA-macroar...

With fertilization, the paternal and maternal contributions to the zygote are not equal. The oocyte and spermatozoon are equipped with complementary arsenals of cellular structures and molecules necessary for the creation of a developmentally competent embryo. We show that the nucleolus is exclusively of maternal origin. The maternal nucleolus is not necessary for oocyte maturation; however, it...

During embryonic pattern formation, the main body axes are established and cells of different developmental fates are specified from a single-cell zygote. Despite the fundamental importance of this process, in plants, the underlying mechanisms are largely unknown. We show that expression dynamics of novel WOX (WUSCHEL related homeobox) gene family members reveal early embryonic patterning event...

The objective of the present study was to investigate the effects of three different culture media on the development of canine somatic cell nuclear transfer (SCNT) embryos. Canine cloned embryos were cultured in modified synthetic oviductal fluid (mSOF), porcine zygote medium-3 (PZM-3), or G1/G2 sequential media. Our results showed that the G1/G2 media yielded significantly higher morula and b...

HE appearance of recombinant cell types in Escherichia coli K-12 has been shown to depend on a sequexe of consecutive steps: ( 1 ) an effective contact between two cells of opposite mating types; (2) a transfer of a portion of the genetic material from the donor cell to the recipient cell; ( 3 ) an integration of the genetic information from both parental strains ixto a recombinant cell with th...

This multicenter cohort study on embryo assessment and outcome data from 11,744 IVF/ICSI cycles with 104,830 oocytes and 42,074 embryos, presents the effect of women's age on oocyte, zygote, embryo morphology and cleavage parameters, as well as cycle outcome measures corrected for confounding factors as center, partner's age and referral diagnosis. Cycle outcome data confirmed the well-known ef...