Dividing cells need to coordinate the separation of chromosomes with the formation of a cleavage plane. There is evidence that microtubule bundles in the interzone region of the anaphase spindle somehow control both the location and the assembly of the cleavage furrow [1-3]. A microtubule motor that concentrates in the interzone, MKLP1, has previously been implicated in the assembly of both the...

OBJECTIVE To investigate whether early embryo cleavage kinetics were affected by type of culture media. METHODS In this prospective sibling-split study, 620 oocytes from 37 patients were randomly allocated into two groups: Cook group and Vitrolife group. Oocytes/embryos in Cook group, would be cultured with Cook sequential culture medium, while oocytes/embryos in Vitrolife group, would be cul...

Patterns of population biology and community structure can be studied by looking closely at the ontogeny reproductive reef-building organisms. This knowledge is particularly important for Caribbean octocorals, which seem to more resilient long-term environmental change than scleractinian corals provide some same ecological services. We monitored development black sea rod, Plexaura homomalla, a ...

Imaging studies, using both luminescent and fluorescent Ca(2+)-sensitive reporters, have revealed that during the first few meroblastic cleavages of the large embryos of teleosts, localized elevations of intracellular Ca(2+) accompany positioning, propagation, deepening and apposition of the cleavage furrows. Here, we will review the Ca(2+) transients reported during the cleavage period in thes...

Globular fossils showing palintomic cell cleavage in the Ediacaran Doushantuo Formation, China, are widely regarded as embryos of early metazoans, although metazoan synapomorphies, tissue differentiation, and associated juveniles or adults are lacking. We demonstrate using synchrotron-based x-ray tomographic microscopy that the fossils have features incompatible with multicellular metazoan embr...

We demonstrate the presence of centrioles in fertilized human oocytes at syngamy. Single or double centrioles within centrosomes were detected by transmission electron microscopy at one pole of the first cleavage spindle in normal and dispermic embryos (25-26 hr after insemination). Sperm centrioles were also closely associated with the male pronucleus (16-20 hr after insemination) in pronuclea...

The mechanisms regulating cell division during development of the mouse pre-implantation embryo are poorly understood. We have investigated whether bone morphogenetic protein (BMP) signaling is involved in controlling cell cycle during mouse pre-implantation development. We mapped and quantitated the dynamic activities of BMP signaling through high-resolution immunofluorescence imaging combined...

Imaging studies, using both luminescent and fluorescent Ca-sensitive reporters, have revealed that during the first few meroblastic cleavages of the large embryos of teleosts, localized elevations of intracellular Ca accompany positioning, propagation, deepening and apposition of the cleavage furrows. Here, we will review the Ca transients reported during the cleavage period in these embryos, w...

Cleavage is a period after fertilization, when a 1-cell embryo starts developing into a multicellular organism. Due to a series of mitotic divisions, the large volume of a fertilized egg is divided into numerous smaller, nucleated cells-blastomeres. Embryos of different phyla divide according to different patterns, but molecular mechanism of these early divisions remains surprisingly conserved....

The fate of F9, a surface antigen common to embryonal carcinoma cells and cleavage embryos, as well as to male germ line cells has been studied in post-implantation mouse embryos. The antigen is readily detected on the surface of 7-day and 8-day, but not on 9-day embryonic cells, using anti-F9 serum absorption experiments and indirect immunofluorescence staining. In addition, it is shown that a...