This paper gives evidence suggesting that one of the two chloroplasts contributed to the zygote of Ulva mutabilis is rapidly destroyed. Chloroplasts in an advanced stage of disintegration can be seen only 4 min after copulation. Radioactive labelling of gametes prior to copulation shows that the disintegrating chloroplast is supplied through the + (plus) gamete, while the chloroplast from the —...

Asymmetric division of zygote is critical for pattern formation during early embryogenesis in plants and animals. It requires integration of the intrinsic and extrinsic cues prior to and/or after fertilization. How these cues are translated into developmental signals is poorly understood. Here through genetic screen for mutations affecting early embryogenesis, we identified an Arabidopsis mutan...

Nuclear-mitochondrial incompatibilities may be responsible for the development failure reported in embryos and fetuses produced by interspecies somatic cell nuclear transfer (iSCNT). Herein we performed xenooplasmic transfer (XOT) by introducing 10 to 15% of buffalo ooplasm into bovine zygotes to assess its effect on the persistence of buffalo mitochondrial DNA (mtDNA). Blastocyst rates were no...

Introgression is the movement of genes or gene flow from one species into the gene pool. wide hybridisation breaks the species barrier for gene transfer and makes it possible to transfer the genome of one species to other, which results alteration in genotypes and phenotypes of the progeny. The main objective of wide hybridisation is to transfer desirable genes, to create genetic variability wh...

Fertilization and zygote development are obligate features of the malaria parasite life cycle and occur during parasite transmission to mosquitoes. The surface protein PFS48/45 is expressed by male and female gametes of Plasmodium falciparum and PFS48/45 antibodies prevent zygote development and transmission. Here, gene disruption was used to show that Pfs48/45 and the ortholog Pbs48/45 from a ...

BACKGROUND: The aim was to study zygote evaluation based on pronuclear morphology under the German embryo protection law, according to which only a maximum of three zygotes are allowed to be cultured for embryo transfer. METHODS: In this prospective multicentre study, a total of 512 treatment cycles was performed at 10 centres, between November 1999 and October 2000. Zygotes were classified int...

BACKGROUND It is known that repeated failure of assisted reproduction treatment (ART) can be due to a paternal effect. This study was undertaken to analyse the possible relationship between ART failure and sperm DNA fragmentation. METHODS Zygote morphology and the percentage of spermatozoa with fragmented DNA (assessed by TUNEL) were compared in two groups using donor oocytes for ICSI attempt...

After fertilization, the sperm and oocyte genomes undergo extensive epigenetic reprogramming to form a totipotent zygote. The dynamic epigenetic changes during early embryo development primarily involve DNA methylation and demethylation. We have previously identified Gse (gonad-specific expression gene) to be expressed specifically in germ cells and early embryos. Its encoded protein GSE is pre...

The sexual cycle of the unicellular Chlamydomonas reinhardtii culminates in the formation of diploid zygotes that differentiate into dormant spores that eventually undergo meiosis. Mating between gametes induces rapid cell wall shedding via the enzyme g-lysin; cell fusion is followed by heterodimerization of sex-specific homeobox transcription factors, GSM1 and GSP1, and initiation of zygote-sp...

The aim of this study is to describe the ultrastructural changes of the egg apparatus associated with fertilisation of the natural tetraploid Trifolium pratense. The pollen tube enters one of the synergids through the filliform apparatus from the micropyle. Before the entry of the pollen tube into the embryo sac, one of the synergids begins to degenerate, as indicated by increased electron dens...