To better understand the differences in cytoskeletal organization between in vivo (IVO) and in vitro (IVM) matured oocytes, we analyzed remodeling of the centrosome-microtubule complex in IVO and IVM mouse oocytes. Fluorescence imaging revealed dramatic differences in meiotic spindle assembly and organization between these two populations. Metaphase spindles at both meiosis I (M-I) and meiosis ...

To perform preimplantation genetic diagnosis for women carrying heteroplasmic mitochondrial DNA (mtDNA) mutations, it is necessary to ensure that the proportion of mutant mtDNA diagnosed in the biopsied cell gives an accurate indication of the mutant load in the remaining embryo. A heteroplasmic mouse model, carrying NZB and BALB mtDNA genotypes, was used to study the relative proportions of ea...

Formation scenarios for polar ring galaxies are studied through N-body simulations that are compared with existing observations. It is shown that polar rings are likely to be formed by tidal accretion of the polar material from a gas rich donor galaxy. The distribution of dark matter in polar ring galaxies is studied: dark halos seem to be flattened towards the polar rings.

The localization of maternal mRNAs during oogenesis plays a central role in axial specification in some insects. Here we describe a polar body-associated asymmetry in maternal transcript distribution in pre-blastoderm eggs of the beetle Tribolium castaneum. Since the position of the polar body marks the future dorsal side of the embryo, we have investigated whether this asymmetry in mRNA distri...

Fundamental interactions between particles, such as the Coulomb law, involve pairs of particles, and our understanding of the plethora of phenomena in condensed-matter physics rests on models involving effective two-body interactions. On the other hand, exotic quantum phases, such as topological phases or spin liquids, are often identified as ground states of hamiltonians with threeor more-body...

EGG maturation in Limnaea stagnalis has been described by Raven (1945, 1949). It exhibits some peculiarities, by which the Limnaea egg seemed to stand apart from all other animal eggs in which the maturation processes have been accurately studied so far. In the first place it appeared that the second maturation spindle arises by a direct and gradual transformation of the centrosphere at the inn...