Xenopus laevis tadpoles and toads were killed at several ages. The structure of the nuclei of the germinal cells has been observed by light and electron microscopes. We distinguish 11 successive stages in nucleolar structure: (1) a single, essentially granular nucleolus in the oogonium (10 /tm diameter), (2) a reticulated nucleolus in the leptotene oocyte, (3) fragmentation of this nucleolus in...

mice are ideal models for icsi experiments because of the ease of culturing eggs/embryos in vitro and the availability of ample genetic information. unfortunately, it has been extremely difficult. in this study we improved the mouse icsi method by using a new holding pipette that was made of two pipettes such that one pipette was pulled and heat merged into the other one. the outer pipette had ...

abstract reproductive biology of female shemaya (alburnus chalcoides) studied with examination of histology, egg diameter and value of sex steroid hormones during spawning phase in the anzali wetland from march 2013 to jun 2014. finally 42 numbers of female fish were examined. the result of sex steroid hormones showed the rate of testosterone hormone in gravid fish was 7.93±1.18 ng/ml; but in r...

Mice are ideal models for ICSI experiments because of the ease of culturing eggs/embryos in vitro and the availability of ample genetic information. Unfortunately, it has been extremely difficult. In this study we improved the mouse ICSI method by using a new holding pipette that was made of two pipettes such that one pipette was pulled and heat merged into the other one. The outer pipette ...

developing a culture system for preantral follicles has important biotechnological implications due to the potential to produce a large number of oocytes for embryo production and transfer. to accomplish this goal, the present study was aimed to culture preantral follicles in the presence of different media, sera and fsh concentrations. six-week-old preantral follicles (95 ± 5 µm) were cultured...

Wild-caught blacklip (Haliotis rubra) and greenlip (H. laevigata) abalone were held from spent condition at 12oC, 14oC, 16oC or 18oC and routinely sampled to examine gonad development. Descriptors of gross structure included the Visual Gonad Index (VGI) and the Modified Gonad Bulk Index (MGBI). Oocyte Diameter Ratio (ODR) and oocyte volume (based on an ellipsoid) were used as descriptors of ova...

Mouse oocytes were placed in Hepes-T6 containing 7.5 μg/ml cytochalasin B and 5μg/ml Hoechst prior to enucleation, and enucleation was performed on oocytes using the manipulator. The oocyte held in place by gentle suction of a holding pipette (oocyte diameter approx.70 μm). The metaphase spindle (arrow) is aspirated into an enucleation pipette (1).

In the present study, various developmental stages of Liza aurata oocyte, especially IV and V stages have been described. On the basis of histological investigations, oocyte development in L. aurata comprises immature (I), the early maturing (II), the late maturing (III), mature (IV), ripe (V), and spent (VI) stages. In the stages I and II, nucleus occupied large volume of oocyte. Vacuolization...