In animal fertilization, multiple sperms typically arrive at an egg cell to "win the race" for fertilization. However, in flowering plants, only one of many pollen tubes, conveying plant sperm cells, usually arrives at each ovule that harbors an egg cell. Plant fertilization has thus been thought to depend on the fertility of a single pollen tube. Here we report a fertilization recovery phenome...

Meiotic chromosomes in an oocyte are not only a maternal genome carrier but also provide a positional signal to induce cortical polarization and define asymmetric meiotic division of the oocyte, resulting in polar body extrusion and haploidization of the maternal genome. The meiotic chromosomes play dual function in determination of meiosis: 1) organizing a bipolar spindle formation and 2) indu...

Although conventional cryopreservation is a proven method for long-term, safe storage of genetic material, protocols used by the zebrafish community are not standardized and yield inconsistent results, thereby putting the security of many genotypes in individual laboratories and stock centers at risk. An important challenge for a successful zebrafish sperm cryopreservation program is the large ...

Among most animals with internal fertilization, females store sperm in specific regions of their reproductive tract for later use. Sperm storage enables prolonged fertility, physical and temporal separation of mating from fertilization and, when females mate with multiple males, opportunities for differential use of the various males' sperm. Thus, stored sperm move within the female reproductiv...

The clinical potential for fertilization was examined by using the human sperm-hamster oocyte assay system after microinjection of round (RS), elongating (ES) or elongated (EtedS) spermatids retrieved from obstructive and non-obstructive azoospermic patients. Freshly isolated, in-vitro cultured and cryopreserved spermatids were utilized. For each category of microinjected spermatids, we demonst...

We studied the effects of soil temperature (8 °C and 15 °C) on barley growth, barley phosphorus (P) uptake and soil P solubility. Barley was grown in a pot experiment in two soils with different P fertilization histories for 22 years. The availability of P was estimated by using 33P-labeled fertilizer and calculating L-values. After cultivation for 22 years at ambient soil temperature without P...

Cell-cell communication and interaction is critical during fertilization and triggers free cytosolic calcium ([Ca2+]cyto) as a key signal for egg activation and a polyspermy block in animal oocytes. Fertilization in flowering plants is more complex, involving interaction of a pollen tube with egg adjoining synergid cells, culminating in release of two sperm cells and their fusion with the egg a...

Many researchers hypothesize that plant richness declines at high soil fertility (and high productivity) due to light limitation. We tested this hypothesis in an old-field by independently manipulating fertilization and light levels via shade cloth (decreased light), vegetation tie-backs (increased light) and vegetation clipping (increased light). Droughts occurred during two of the four years ...

The aim of this study was to investigate whether the sperm chromatin structure assay (SCSA) results after swim-up are related to fertilization rates, embryo quality and pregnancy rates following in vitro fertilization (IVF). A total of 223 couples undergoing IVF in our hospital from October 2008 to September 2009 were included in this study. Data on the IVF process and sperm chromatin structure...