Oh Yeah, Developmental Biology!

livasperiklis:

Divide and define: Clues to understanding how stem cells produce different kinds of cells

The apical tip of fruitfly testis containing germline stem cells and differentiating germ cells.…

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raptinawe:

This confocal micrograph shows stage V–VI oocytes (800–1000 micron diameter) of an African clawed frog (Xenopus laevis), a model organism used in cell and developmental biology research. Each oocyte is surrounded by thousands of follicle cells, shown in the image by staining DNA blue. Blood vessels, which provide oxygen to the oocyte and follicle cells, are shown in red. The ovary of each adult female Xenopus laevis contains up to 20 000 oocytes. Mature Xenopus laevis oocytes are approximately 1.2 mm in diameter, much larger than the eggs of many other species. (Photo by Vincent Pasque, University of Cambridge/Wellcome Images)

(via Up Close: 2012 Wellcome Image Awards)

scienceyoucanlove:

Transit-amplifying neuroblast lineages in the larval brain

Throughout embryonic and larval development, neural precursor cells called neuroblasts divide in a self-renewing manner and produce large numbers of small, differentiating daughter cells. These daughter cells eventually give rise to the neurons and glia of the central nervous system. It was previously thought that all neuroblast daughters are ganglion mother cells (GMCs) — cells that divide terminally to produce differentiated neurons or glia. We found that a distinct subpopulation of larval neuroblasts do not produce ganglion mother cells, but instead generate small, secondary neuroblasts. The secondary neuroblast acts as an intermediate precursor, dividing several times to give rise to multiple GMCs. Adding this transit-amplification step to the neuroblast lineage allows production of GMCs and neurons at a faster rate.

In these complementary images of a single larval brain lobe, primary neuroblasts appear as large circles outlined by phalloidin staining (left, green; right, blue). Primary neuroblasts of the classical lineages express the neural precursor marker Asense (red). An asensereporter (green, right, asense-Gal4 » CD8-GFP) is also expressed in the classical neuroblast and many of its progeny. By contrast, primary neuroblasts of the transit-amplifying lineages do not express Asense or the asense reporter. The asense reporter is not detectable in small secondary neuroblasts (right), even though they express Asense protein.

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blamoscience:

Technicolor Stickleback
This juvenile fish has developing bone stained red and developing cartilage stained blue.
Mark Currey, PLoS Genetics, doi:10.1371/image.pgen.v06.i02.g001