Search results for "Gamete"
showing 4 items of 24 documents
Time-Lapse Dynamics of the Mouse Oocyte Chromatin Organisation during Meiotic Resumption
2014
In the mammalian oocyte, distinct patterns of centromeres and pericentromeric heterochromatin localisation correlate with the gamete’s developmental competence. Mouse antral oocytes display two main types of chromatin organisation: SN oocytes, with a ring of Hoechst-positive chromatin surrounding the nucleolus, and NSN oocytes lacking this ring. When matured to MII and fertilised, only SN oocytes develop beyond the 2-cell, and reach full term. To give detailed information on the dynamics of the SN or NSN chromatin during meiosis resumption, we performed a 9 hr time-lapse observation. The main significant differences recorded are: (1) reduction of the nuclear area only in SN oocytes; (2) ~17…
Ploidy manipulation for genetic improvement in some Mediterranean fruit crops
2017
Plant breeding is focused on selection of new genotypes with improved traits. Conventional methods based on hybridization and those based on biotechnology (somatic hybridization, genetic transformation, ploidy manipulation, etc.) are used to create novel genetic variations. Biotechnology provides powerful tools for plant breeding, for instance, haploid technology allows achievement of homozygous lines from heterozygous parents in one step, which reduces significantly the time required by conventional methods. Concerning woody species, characterized by self-incompatibility, long juvenile period and high degree of heterozygosity, this technique is the only way to get homozygous lines. Haploid…
Effects of Sulfamethoxazole on Fertilization and Embryo Development in the Arbacia lixula Sea Urchin
2022
To date, drugs released into the aquatic environment are a real problem, and among antibiotics, sulfamethoxazole is the one most widely found in wastewater; thus, the evaluation of its toxicity on marine organisms is very important. This study, for the first time, investigates the in vitro effects of 4 concentrations of sulfamethoxazole (0.05 mg/L, 0.5 mg/L, 5 mg/L, 50 mg/L) on the fertilization and development of the sea urchin Arbacia lixula. The gametes were exposed to drugs in three different stages: simultaneously with, prior to, and post-fertilization. The results show a significant reduction in the percentage of fertilized oocytes at the highest drug concentrations. Moreover, an incr…
Bisphenol A Effects on the Growing Mouse Oocyte Are Influenced by Diet1
2009
Growing evidence suggests that exposure to bisphenol A (BPA) has the ability to disrupt several different stages of oocyte development. To date, most attention has focused on the effects of BPA on the periovulatory oocyte, and considerable variation is evident in the results of these studies. In our own laboratory, variation in the results of BPA studies conducted at different times appeared to correlate with changes in mill dates of animal feed. This observation, coupled with reports by others that dietary estrogens in feed are a confounding variable in studies of endocrine-disrupting chemicals, prompted us to evaluate the effect of diet on the results of BPA studies of the periovulatory o…