Embryogenesis and Development

Watching a embryo develop from a single cell to complex organism is amazing for kids and senior scientist alike.  How can one not be interested in biology after observing early development under a microscope.  Time lapse microscopy with the QX5 is a great way to observe early development.  On this site, I show two movies of early cell divisions that begin after the fertilization of a frog (Xenopus laevis) egg and a sea urchin egg.  The early cell divisions are particularly dramatic with the frog egg since they are very large (a bit larger than 1 mm in diameter).  The sea urchin embryo becomes ciliated and swims away at the end of the video.  These were taken as “overnight” movies, with QX5 acquiring an image once every 2 minutes.  With the miXscope software, you can also “cycle” the lamp (turning it on only with it takes the image), which prevents excess illumination of the specimen and burnout of the lamp bulb.  For such an inexpensive microscope, the stage/focus was remarkably stable even when left unattended for many hours.

You also can look at later stages of development, such as the movie of Drosophila “gastrulation” made by Dr. Eric Weischaus (Nobel Laureate, Princeton University).  Here you can seen the dramatic movement of cells (at this stage, individual cells are too small to see) that causes an invagination that will give rise to the three embryonic germ layers: ectoderm, endoderm and mesoderm.   Here, side illumination with a fiber optic lamp was employed to produce better contrast to visualize the embryo.  You can learn more about gastrulation at http://www.gastrulation.org/.

Early developmental forms of different animals can be fun to explore with the QX5.  Below, you can find  “real time” 60x movies of a squid hatchling with its beautiful pigment markings, a fly larvae crawling across a dish, and the swimming pluteus stage of a sea urchin .

Another great system for kids and QX5 microscope for studying development is the zebra fish embryo.  Zebra fish are easy to obtain and fertilized eggs are easy to collect.  Kids can either make a long time lapse move or just check the development from eggs to fish by examining them everyday (easier).  It is very cool to observe the stage when the heart starts to beat.  I will add a video early zebra fish development at a latter date.  You can look at movies on YouTube for zebrafish development; however, the contrast will not be as good with QX5.

 

Movies:

Squid hatchling, 60X (10.3 MB movie)(476 KB version)

Gastrulation of a Drosophila (fruit fly) embryo (21.6 MB movie)(1.5 MB version)

Drosophila (fruit fly) larvae (2.2 MB movie)

Sea urchin pluteus, 200X, 1 frame/sec (540 KB movie)

Development of a sea urchin (early cell divisions after fertilization), 200x, 1 frame/2 min
Overnight movie, embryo swims away at the end. (1.3 MB movie)

Frog (Xenopus laevis) embryogenesis (early cell divisions), 60X, 1 frame/2 min (7.6 MB movie)(312 KB version)