Fertilization is one of the most important events in living organisms to generate a new life with a mixed genetic background. To achieve successful fertilization, sperm and eggs must undergo complex processes in a sequential order. Fertilization of marine invertebrate type has been studied for more than a hundred years. Ascidian sperm are attracted by chemoattractants from eggs and bind to the vitelline coat. Subsequently, sperm penetrate through the vitelline coat proteolytically and finally fuse with the egg plasma membrane. Here, we summarize the fertilization mechanisms of ascidians, particularly from sperm-egg interactions to sperm penetration of the egg coat. Since ascidians are hermaphrodites, inbreeding depression is a serious problem. To avoid self-fertilization, ascidians possess a self-incompatibility system. In this review, we also describe the molecular mechanisms of the self-incompatibility system in type A governed by three allelic gene pairs of and .
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http://dx.doi.org/10.3389/fcell.2021.827214 | DOI Listing |
Pol J Vet Sci
September 2024
Department of Clinics, Veterinary College and Research Institute, Tamil Nadu Veterinary and Animal Sciences University, Namakkal-637 001, India.
The aim of this study was to assess the in vitro penetration rate of antioxidant enriched frozen thawed Kangayam bull semen. For the current investigation, 5-7-year-old Kangayam bulls were used. The semen was collected twice per week and two ejaculates were collected each time.
View Article and Find Full Text PDFCommun Biol
December 2024
The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, 1088639, Japan.
One of the major age-related declines in female reproductive function is the reduced quantity and quality of oocytes. Here we demonstrate that structural changes in the zona pellucida (ZP) were associated with decreased fertilization rates from 34- to 38-week-old female mice, equivalent to the mid-reproductive of human females. In middle-aged mouse ovaries, the decline in the number of transzonal projections was accompanied by a decrease in cumulus cell-oocyte interactions, resulting in a deterioration of the oocyte quality.
View Article and Find Full Text PDFJ Reprod Dev
December 2024
Department of Integrated Applied Life Science, Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi, Yamanashi 400-0016, Japan.
Calcium release from the endoplasmic reticulum via sperm-derived phospholipase C zeta is crucial for oocyte activation during fertilization. Chloroquine (CQ) inhibits the increase in cytoplasmic calcium. This study investigated the effects of CQ on fertilization and oocyte activation.
View Article and Find Full Text PDFJ Transl Med
December 2024
Department of Biological Science, University of Tulsa, Tulsa, Oklahoma, USA.
Background: The mechanisms enabling sperm to locate unfertilized eggs within the fallopian tubes remain a subject of debate in reproductive biology. Previous studies using polytocous mammals observed a 1:1 sperm-egg ratio within the ampulla at the time of fertilization. From these observations, it is hypothesized that this mechanism could be linked to sperm-egg fusion, such that unfertilized eggs may attract sperm until fusion occurs, whereupon the attraction ceases.
View Article and Find Full Text PDFJ Exp Bot
November 2024
The School of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
In flowering plants, pollen grain must undergo a series of critical processes, including adhesion, hydration, and germination, which are dependent on the stigma, to develop a pollen tube. This pollen tube then penetrates the stigma to reach the internal tissues of pistil, facilitating the transport of non-motile sperm cells to the embryo sac for fertilization. However, the dry stigma, characterized by the absence of an exudate that typically envelops the wet stigma, functions as a multi-layered filter in adhesion, hydration, germination and penetration that permits the acceptance of compatible pollen or tubes while rejecting incompatible ones, thereby protecting the embryo sac from ineffective fertilization and maintaining species specificity.
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