Background: The cause of fertilization failure in IVF is most often due to the absence of sperm penetration but the reason why fertilization does not occur when intracytoplasmic sperm injection (ICSI) is applied is not clear. However some intrinsic oocyte problems may also be responsible for fertilization failure. It has been reported that 13% of unfertilized oocytes after IVF show morphologica...

Sperm competition and female choice are fundamentally driven by gender differences in investment per offspring and are often manifested as differences in variance in reproductive success: males compete and have high variance; most females are mated and have low variance. In marine organisms that broadcast spawn, however, females may encounter either sperm limitation or sperm competition. I meas...

Recently, we have provided evidence for the involvement of a cytosolic tyrosine-phosphorylatable 70 kDa oocyte protein in Rhinella arenarum (Anura: Bufonidae) fertilization. The aim of the present work was to characterize its phosphorylation, determine the identity of this protein and establish its biological role during the fertilization process. Tyrosine phosphorylation of the 70 kDa protein ...

Outcrossing and self-fertilization are fundamental strategies of sexual reproduction, each with different evolutionary costs and benefits. Self-fertilization is thought to be an evolutionary "dead-end" strategy, beneficial in the short term but costly in the long term, resulting in self-fertilizing species that occupy only the tips of phylogenetic trees. Here, we use volvocine green algae to in...

With the introduction of intracytoplasmic sperm injection (ICSI), couples with severe male factor infertility have been able to achieve fertilization and clinical pregnancy rates comparable to other in vitro fertilization patients. However, despite the utilization of microsurgical sperm injection techniques, failure of fertilization still occurs in a few patients. How such fertilization failure...

Grassland managements can affect carbon (C) and nitrogen (N) storage in grassland ecosystems with consequent feedbacks to climate change. We investigated the impacts of compound fertilization and clipping on grass biomass, plant and soil (0-20 cm depth) C, N storage, plant and soil C: N ratios, soil microbial activity and diversity, and C, N sequestration rates in grassland in situ in the Natio...

Although varicocelectomy is generally believed to improve semen quality and the hamster egg penetration assay, these parameters do not correlate well with in vitro fertilization (IVF) success. The effect of varicocelectomy on IVF of human oocytes was examined on thirteen couples with normal female fertility, but severe oligozoospermia and the presence varicocele in the males with failure of fer...

An egg-that took weeks to months to make in the adult-can be extraordinarily transformed within minutes during its fertilization. This review will focus on the molecular biology of the specialized secretory vesicles of fertilization, the cortical granules. We will discuss their role in the fertilization process, their contents, how they are made, and the molecular mechanisms that regulate their...

This study aimed to evaluate the impact of a short insemination procedure on embryo development, assess the reliability of a fertilization check prior to the appearance of pronuclei and elucidate the role of rescue intracytoplasmic sperm injection (R-ICSI). Patients who had ≥9 eggs, were aged <38 years and had normal semen samples were included. The sibling eggs of each patient were divided int...

In order to discover the advantages and disadvantages of different fertilization regimes and identify the best management practice of fertilization in greenhouse fields, soil enzyme activities involved in carbon (C) transformations, soil chemical characteristics, and crop yields were monitored after long-term (20-year) fertilization regimes, including no fertilizer (CK), 300 kg N ha-1 and 600 k...