Credit: Zhang, Y.V., Aikin, T.J., Li, Z., and Montell, C., University of California, Santa Barbara
It’s a problem that parents know all too well: a child won’t eat because their oatmeal is too slimy or a slice of apple is too hard. Is the kid just being finicky? Or is there a biological basis for disliking food based on its texture? This image, showing the tongue (red) of a fruit fly (Drosophila melanogaster), provides some of the first evidence that biology could indeed play a role .
The image shows a newly discovered mechanosensory nerve cell (green), which is called md-L, short for multidendritic neuron in the labellum. When the fly extends its tongue to eat, the hair bristles (short red lines) on its surface bend in proportion to the consistency of the food. If a bristle is bent hard enough, the force is detected at its base by one of the arms of an md-L neuron. In response, the arm shoots off an electrical signal that’s relayed to the central part of the neuron and onward to the brain via the outgoing informational arm, or axon.
Cell biologists now possess an unprecedented set of laboratory tools to look inside living cells and study their inner workings. Many of these tools have only recently appeared, while others have deeper historical roots. Combining the best of the old with the best of the new, researchers now have the power to explore the biological underpinnings of life in ways never seen before.
That’s the story of this video from the lab of Roberto Weigert, an intramural researcher with NIH’s National Cancer Institute and National Institute of Dental and Craniofacial Research. Weigert is a cell biologist who specializes in intravital microscopy (IVM), an extremely high-resolution imaging tool that traces its origins to the 19th century. What’s unique about IVM is its phenomenal resolution can be used in living animals, allowing researchers to watch biological processes unfold in organs under real physiological conditions and in real time.
Seasons Greetings! What looks like a humble wreath actually represents an awe-inspiring gift to biomedical research: a new imaging technique that adds a dash of color to the formerly black-and-white world of electron microscopy (EM). Here the technique is used to visualize the uptake of cell-penetrating peptides (red) by the fluid-filled vesicles (green) of the endosome (gray), a cellular compartment involved in molecular transport. Without the use of color to draw sharp contrasts between the various structures, such details would not be readily visible.
This innovative technique has its origins in a wonderful holiday story. In December 2003, Roger Tsien, a world-renowned researcher at the University of California, San Diego (UCSD), decided to give himself a special present. With the lab phones still and email traffic slow for the holidays, Tsien decided to take advantage of the peace and quiet to spend two weeks alone at the research bench, pursuing an intriguing, yet seemingly wacky, idea. He wanted to find a way to deposit ions of a rare earth metal, called lanthanum, directly into cells as the vital first step in creating a new imaging technique designed to infuse EM with some much-needed color. After the holidays, when the lab returned to its usual hustle and bustle, Tsien handed off his project to Stephen Adams, a research scientist in his lab, thereby setting in motion a nearly 13-year quest to perfect the colorful new mode of EM.
This Fourth of July, many of you will spread out a blanket and enjoy an evening display of fireworks with their dramatic, colorful bursts. But here’s one pyrotechnic pattern that you’ve probably never seen. In this real-time video, researchers set off some fluorescent fireworks under their microscope lens while making an important basic discovery about how microtubules, the hollow filaments that act as the supportive skeleton of the cell, dynamically assemble during cell division.
The video starts with a few individual microtubule filaments (red) growing linearly at one end (green). Notice the green “comets” that quickly appear, followed by a red trail. Those are new microtubules branching off. This continuous branching is interesting because microtubules were generally thought to grow linearly in animal cells (although branching had been observed a few years earlier in fission yeast and plant cells). The researchers, led by Sabine Petry, now at Princeton University, Princeton, NJ, showed for the first time that not only do new microtubules branch during cell division, but they do so very rapidly, going from a few branches to hundreds in a matter of minutes .
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.