background: the effect of temperature and humidity on the maturation of toxocara cati eggs in an in vitro system was investigated. methods: suspensions of toxocara cati eggs, with 5% formalin/saline or 2.5% formalin/ringer were prepared and maintained at 37 °c under 40% humidity or at 25 °c under 98% humidity for 3 weeks for egg development. results: the suspension sample mixed by 2.5% formalin...

Previous studies (Nomura et al. (1991) Dev. Biol. 143, 289-296 (1993) Dev. Biol. 159, 288-297) determined the time of DNA replication period (S phase) in starfish eggs fertilized either during or after oocyte maturation. Here proliferating cell nuclear antigen (PCNA) localized within nuclei of starfish eggs was detected with an anti-PCNA human antiserum. Using a confocal laser scanning microsco...

In an attempt to examine genomic function of the oocyte nucleus during meiotic maturation, the effects of X-irradiation on the oocyte of the frog (Rana pipiens) were studied. When oocytes were irradiated with 6000-36000 R before initiation of maturation, the ovulated eggs frequently failed to be fertilized and the jelly surrounding the unfertilizable eggs was always damaged. However, the egg it...

The universal signal for egg activation at fertilization is a rise in cytoplasmic Ca(2+) with defined spatial and temporal kinetics. Mammalian and amphibian eggs acquire the ability to produce such Ca(2+) signals during a maturation period that precedes fertilization and encompasses resumption of meiosis and progression to metaphase II. In Xenopus, immature oocytes produce fast, saltatory Ca(2+...

In an attempt to examine genomic function of the oocyte nucleus during meiotic maturation, the effects of X-irradiation on the oocyte of the frog (Rana pipiens) were studied. When oocytes were irradiated with 6000-36000 R before initiation of maturation, the ovulated eggs frequently failed to be fertilized and the jelly surrounding the unfertilizable eggs was always damaged. However, the egg it...

Background This study aimed to investigate whether Artificial Seminiferous Tubules (AST) coated with testicular extra cellular matrix (ECM) support maturation of spermatogenic cells from immature testes. MaterialsAndMethods Medical grade tubes coated with testicular ECM were used. Testes from immature mice were loaded in the concentration of 10000- 20000/ml. Tubes were then immersed in germ cel...

Ca(2+) is the universal signal for egg activation at fertilization in all sexually reproducing species. The Ca(2+) signal at fertilization is necessary for egg activation and exhibits specialized spatial and temporal dynamics. Eggs acquire the ability to produce the fertilization-specific Ca(2+) signal during oocyte maturation. However, the mechanisms regulating Ca(2+) signaling differentiation...

For development to proceed normally, animal eggs must undergo a maturation process that ultimately depends on phosphorylations of key regulatory proteins. To analyze the kinases that mediate these phosphorylations, eggs of marine nemertean worms have been treated with pharmacological modulators of intracellular signaling pathways and subsequently probed with immunoblots employing phospho-specif...

Regulation of animal oocyte maturation is hypothesized to involve heterotrimeric G-proteins. It is difficult to test this hypothesis though without knowing what G-proteins are present in these cells and where are they localized. We set out to test the hypothesis that G-proteins regulate maturation in the sea urchin oocyte by identifying resident G-proteins in oocytes and eggs, and then investig...