chicken
Snapshots of Life: Imperfect but Beautiful Intruder
Posted on by Dr. Francis Collins
Credit: Boon Chong Goh, Beckman Institute, University of Illinois at Urbana-Champaign
The striking image you see above is an example of what can happen when scientists combine something old with something new. In this case, a researcher took the Rous sarcoma virus (RSV)—a virus that’s been studied for more than century because of its ability to cause cancer in chickens and the insights it provided on human oncogenes [1, 2]—and used modern computational tools to generate a model of its atomic structure.
Here you see an immature RSV particle that’s just budded from an infected chicken cell and entered the avian bloodstream. A lattice of proteins (red) held together by short peptides (green) cover the outer shell of the immature virus, shielding other proteins (blue) that make up an inner shell.
Snapshots of Life: Green Eggs and Heart Valves
Posted on by Dr. Francis Collins
Credit: Jessica Ryvlin, Stephanie Lindsey, and Jonathan Butcher, Cornell University, Ithaca, NY
What might appear in this picture to be an exotic, green glow worm served up on a collard leaf actually comes from something we all know well: an egg. It’s a 3-day-old chicken embryo that’s been carefully removed from its shell, placed in a special nutrient-rich bath to keep it alive, and then photographed through a customized stereo microscope. In the middle of the image, just above the blood vessels branching upward, you can see the outline of a transparent, developing eye. Directly to the left is the embryonic heart, which at this early stage is just a looped tube not yet with valves or pumping chambers.
Developing chicks are one of the most user-friendly models for studying normal and abnormal heart development. Human and chick hearts have a lot in common structurally, with four chambers and four valves pumping two circulations of blood in parallel. Unlike mammalian embryos tucked away in the womb, researchers have free range to study the chick heart in or out of the egg as it develops from a simple looped tube to a four-chambered organ.
Jonathan Butcher and his NIH-supported research group at Cornell University, Ithaca, NY, snapped this photo, a winner in the Federation of American Societies for Experimental Biology’s 2015 BioArt competition, to monitor differences in blood flow through the developing chick heart. You can get a sense of these differences by the varying intensities of green fluorescence in the blood vessels. The Butcher lab is interested in understanding how the force of the blood flow triggers the switching on and off of genes responsible for making functional heart valves. Although the four valves aren’t yet visible in this image, they will soon elongate into flap-like structures that open and close to begin regulating the normal flow of blood through the heart.
Snapshots of Life: The Biological Basis of Hearing
Posted on by Dr. Francis Collins
Credit: Peter Barr-Gillespie and Kateri Spinelli, Oregon Health & Science University, Portland
Did you know that chickens have ears? Well, here’s the evidence—you’re looking at a micrograph of sensory hair cells that make up the inner ear of Gallus gallus domesticus, otherwise known as the domestic chicken. Protruding from each hair cell is a tall bundle of stiff appendages, called stereocilia, that capture vibrations and enable the chicken to hear everything from grain being poured into a feeder to the footsteps of a wily fox. The flatter area is occupied by supporting cells, which have recently been shown to have the capacity to regenerate damaged or destroyed hair cells.
Peter Barr-Gillespie and Kateri Spinelli of Oregon Health & Science University, Portland used a scanning electron microscope to capture this image—one of the winners of the Federation of American Societies for Experimental Biology’s 2014 BioArt competition—while studying how these cells convert sound waves into brain waves. It is generally known that sound waves cause the stereocilia on each hair cell to oscillate in concert. These vibrating stereocilia trigger electrical changes in the hair cells, which then send signals to the brain. Barr-Gillespie’s group focuses on the actual molecules that build the stereocilia and translate the vibrations into brain signals.
