Snapshots of Life: Neurons in a New Light

Mouse Midbrain

Credit: Michael Shribak, Marine Biological Laboratory, Woods Hole, MA

Birds do it, bees do it, and even educated fleas do it. No, not fall in love, as the late Ella Fitzgerald so famously sang. Birds and insects can see polarized light—that is, light waves transmitted in a single directional plane—in ways that provides them with a far more colorful and detailed view of the world than is possible with the human eye.

Still, thanks to innovations in microscope technology, scientists have been able to tap into the power of polarized light vision to explore the inner workings of many complex biological systems, including the brain. In this image, researchers used a recently developed polarized light microscope to trace the spatial orientation of neurons in a thin section of the mouse midbrain. Neurons that stretch horizontally appear green, while those oriented at a 45-degree angle are pinkish-red and those at 225 degrees are purplish-blue. What’s amazing is that these colors don’t involve staining or tagging the cells with fluorescent markers: the colors are generated strictly from the light interacting with the physical orientation of each neuron.

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Cool Videos: Looking Inside Living Cells

celldancevideoCell 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.

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Merry Microscopy and a Happy New Technique!

Color EM WreathSeasons 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.

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Cool Videos: Fireworks under a Microscope

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 [1].

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