Damaged nuclei fallout from the cortex to interior planes (magenta, yellow) of a syncytial embryo. Image Credit: Brandt Warecki and Simon Titen

Live video imaging of the uterus tissue of the parasitic nematode Brugia pahangi. DNA is stained with Syto-11, a live-imaging nucleic acid stain. Each bundle of nuclei represents a single growing embryo, which will continue to divide and grow into mature microfilariae as they move along the uterus towards the anterior of the worm. Filarial nematodes give live birth to microfilariae. Image Credit: Laura Chappell

Live imaging of the uterine tissue of the parasitic nematode Brugia pahangi. DNA is stained with Syto-11. The small nuclei that take up the vast majority of this image are the nuclei of sperm heads. Sperm are stored in this organ and fertilize mature oocytes as they pass through. These mature oocytes and fertilized eggs can be seen as the larger nuclei floating among the sea of sperm. Image Credit: Laura Chappell

Live imaging of the uterine tissue of the parasitic nematode Brugia pahangi. DNA is stained with Syto-11. Here you can see the two different germline structures side-by-side. The germline of the parasitic nematode acts as an assembly line for the growing embryos, which mature as they move along the uterus towards the head of the worm (down in this image). The two uteri depicted in this image contain embryos at different stages in development, with larger, more developed embryos seen in the uterus on the right. Image Credit: Laura Chappell

The uterus-ovary junction of the germline tissue of a Brugia pahangi parasitic nematode. The long, thin section of tissue is the actin-rich ovary which deposits mature oocytes into the uterus. The larger uteran tissue acts as a storage compartment for sperm from previous mating events. As the mature oocytes pass through this section, they become fertilized by the stored sperm (here stained with PI and DAPI). Image Credit: Laura Chappell

6,000 cells in an instant: In cellularizing Drosophila embryos, actin is apically enriched above centrosome pairs. Actin is also enriched basally at the leading edge of the ingressing furrow (arrows). Microtubules (MT) emanate basally from apically localized centrosome pair.

Membrane addition drives cytokinesis: Live analysis of ingression of the contractile furrow during cytokinesis. Arrows highlight actin coated vesicles fusing with ingressing furrow.

Getting rid of the bad apples: In response to DNA damage, multicellular organisms have two options – repair the damage or eliminate the damaged nuclei. The pre-cellular Drosophila embryo relies extensively on the latter option. Damaged nuclei are released from the cortex into the interior of the embryo.

Wallpaper from house in the Haight: DNA, Actin, Microtubules.

The mystery of virgin birth solved: Accessory nuclei derived from the oocyte nucleus are packed with gamma tubulin, the catalyst for centriole formation eliminating the need for a sperm derived basal body/centriole.

Standing room only! Rapidly dividing nuclei during the late blastoderm divisions of the Drosophila embryo. Spindle fibers separate sister telophase nuclei.

A multi-plane time lapse series of microtubules and actin through a cortical nuclear cycle. Each column is a single time point with nine images at 1um intervals. Image Credit: Carol Koyama, Blake Riggs. GFP-moesin kindly supplied by Dan Kiehart.

In the crowded environment of the syncytial blastoderm embryo, astral microtubules maintain separation and even spacing of the nuclei.

Nuclear division without centrosomes: Spindle assembly with (left panels) and without (right panels) centrosomes.

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