introduction: to evaluate the effect of electroactivation on fertilization and embryo development up to 8-cell stage, after intracytoplasmic injection of severely amorphous sperm. material and methods: oocytes (168) from 13 patients with severe- teratospermia undergoing icsi were divided into control (83) and electro activation (85) groups. in the latter group, oocytes were electrically activat...

The property of primordial germ cells (PGCs) in fragmented goldfish embryos was investigated. When 1- and 2- cell embryos were cut at several perpendicular levels at the animal-vegetal axis, cells expressing vas mRNA were observed in the resultant embryos derived from all kinds of animal fragments. Blastodisc fragments from the 1- to 2-cell stage developed to spherical embryos containing yolk b...

In flowering plants, pollen grains germinate to form pollen tubes that transport male gametes (sperm cells) to the egg cell in the embryo sac during sexual reproduction. Pollen tube biology is complex, presenting parallels with axon guidance and moving cell systems in animals. Pollen tube cells elongate on an active extracellular matrix in the style, ultimately guided by stylar and embryo sac s...

STUDY QUESTION Are there associations between early time-lapse parameters, expression of candidate embryo viability genes in cumulus cells and embryo quality on Day 5? SUMMARY ANSWER Early time-lapse parameters correlate to the expression levels of candidate embryo viability genes in cumulus cells but a combined analysis including both time-lapse and candidate gene expression did not identify...

A binary vector carrying two WUSCHEL-related homeobox (WOX) genes, WOX2 and WOX8, under the control of a chemical-inducible expression system, worked in transformation N. paniculata, recalcitrant species Nicotiana. The resulting transformants exhibited improved culture performance regeneration from leaf segments suspended cells. Multicellular masses generated freely cells showed specific cell d...

Postembryonic organ formation of plants is fueled with cells from the stem cell niches in the shoot and root meristems. During the last two decades many players that regulate stem cell maintenance have been identified. With these factors in hand, the mechanisms establishing stem cell niches during embryo development can be addressed. Here we discuss current models of how the shoot meristem stem...

Background: The aim of this study was to establish a cell-free sequential culture system that can support high levels of in vitro embryo development and blastocyst formation from bovine zygotes. To this end, this investigation was carried out to evaluate the effects of glucose, serum and EDTA on bovine zygote in vitro development. Materials and Methods: Bovine presumptive zygotes were derived f...

Mammalian oocyte maturation and early embryo development processes are Ca(2+)-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca(2+) and its dynamic changes in the processes of bovine oocytes maturation, in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) embryo development. During the germinal v...

Among spiral cleaving embryos (e.g. mollusks and annelids), it has long been known that one blastomere at the four-cell stage, the D cell, and its direct descendants play an important role in axial pattern formation. Various studies have suggested that the D quadrant acts as the organizer of the embryonic axes in annelids, although this has never been demonstrated directly. Here we show that D ...

BACKGROUND The orientation of the mitotic spindle influences the asymmetric distribution of cytoplasmic determinants and the positioning of the sibling cell, and therefore has important influences on cell-fate determination and patterning of the embryo. Both the establishment of an axis of polarity and the adjustment of this axis with respect to the coordinates of the embryo have to be controll...