confocal microscope
Snapshots of Life: Making Sense of Smell
Posted on by Dr. Francis Collins
Credit: Jeremy McIntyre, University of Florida College of Medicine, Gainesville
You’ve probably learned the hard way about how the grocery list can go out the window when you go shopping on an empty stomach. Part of the reason is that our sense of smell intensifies when we’re hungry, making the aroma of freshly baked cookies, fried chicken, and other tempting goodies even more noticeable. And this beautiful micrograph helps to provide a biological explanation for this phenomenon.
The image, which looks like something that Van Gogh might have painted, shows a thick mesh of neurons in a small cross section of a mouse’s olfactory bulb, a structure located in the forebrain of all vertebrates (including humans!) that processes input about odors detected by the nose. Here, you see specialized neurons called mitral cells (red) that can receive signals from the hypothalamus, a brain region known for its role in hunger and energy balance. Also fluorescently labeled are receptors that detect acetylcholine signals from the brain (green) and the nuclei of all cells in the olfactory bulb (blue).
Snapshots of Life: Coming Face to Face with Development
Posted on by Dr. Francis Collins
Credit: Oscar Ruiz and George Eisenhoffer, University of Texas MD Anderson Cancer Center, Houston
Zebrafish (Danio rerio) is a favorite model for studying development, in part because its transparent embryos make it possible to produce an ever-growing array of amazingly informative images. For one recent example, check out this Federation of American Societies for Experimental Biology’s 2016 BioArt winner, which shows the developing face of a 6-day-old zebrafish larva.
Yes, those downturned “lips” are indeed cells that will go on to become the fish’s mouth. But all is not quite what it appears: the two dark circles that look like eyes are actually developing nostrils. Both the nostrils and mouth express high levels of F-actin (green), a structural protein that helps orchestrate cell movement. Meanwhile, the two bulging areas on either side of the fish’s head, which are destined to become eyes and skin, express keratin (red).
Oscar Ruiz, who works in the lab of George Eisenhoffer at The University of Texas MD Anderson Cancer Center, Houston, used a confocal microscope to create this image. What was most innovative about his work was not the microscope itself, but how he prepared the sample for imaging. With traditional methods, researchers can only image the faces of zebrafish larvae from the side or the bottom. However, the Eisenhoffer lab has devised a new method of preparing fish larvae that makes it possible to image their faces head-on. This has enabled the team to visualize facial development at much higher resolution than was previously possible.
Creative Minds: New Piece in the Crohn’s Disease Puzzle?
Posted on by Dr. Francis Collins
Gwendalyn Randolph
Back in the early 1930s, Burrill Crohn, a gastroenterologist in New York, decided to examine intestinal tissue biopsies from some of his patients who were suffering from severe bowel problems. It turns out that 14 showed signs of severe inflammation and structural damage in the lower part of the small intestine. As Crohn later wrote a medical colleague, “I have discovered, I believe, a new intestinal disease …” [1]
More than eight decades later, the precise cause of this disorder, which is now called Crohn’s disease, remains a mystery. Researchers have uncovered numerous genes, microbes, immunologic abnormalities, and other factors that likely contribute to the condition, estimated to affect hundreds of thousands of Americans and many more worldwide [2]. But none of these discoveries alone appears sufficient to trigger the uncontrolled inflammation and pathology of Crohn’s disease.
Other critical pieces of the Crohn’s puzzle remain to be found, and Gwendalyn Randolph thinks she might have her eyes on one of them. Randolph, an immunologist at Washington University, St. Louis, suspects that Crohn’s disease and other related conditions, collectively called inflammatory bowel disease (IBD), stems from changes in vessels that carry nutrients, immune cells, and possibly microbial components away from the intestinal wall. To pursue this promising lead, Rudolph has received a 2015 NIH Director’s Pioneer Award.
Snapshots of Life: Development in Exquisite Detail
Posted on by Dr. Francis Collins
Credit: Shachi Bhatt and Paul Trainor, Stowers Institute for Medical Research, Kansas City, MO
If you’ve ever tried to take photos of wiggly kids, you know that it usually takes several attempts before you get the perfect shot. It’s often the same for biomedical researchers when taking images with microscopes because there are so many variables—from sample preparation to instrument calibration—to take into account. Still, there are always exceptions where everything comes together just right, and you are looking at one of them! On her first try at using a confocal microscope to image this cross-section of a mouse embryo’s torso, postdoc Shachi Bhatt captured a gem of an image that sheds new light on mammalian development.
Bhatt, who works in the NIH-supported lab of Paul Trainor at the Stowers Institute for Medical Research, Kansas City, MO, produced this micrograph as part of a quest to understand the striking parallels seen between the development of the nervous system and the vascular system in mammals. Fluorescent markers were used to label proteins uniquely expressed in each type of tissue: reddish-orange delineates developing nerve cells; gray highlights developing blood vessels; and yellow shows where the nerve cells and blood vessels overlap.
