Cool Video: How a Microtubule Builds and Deconstructs

A microtubule, part of the cell’s skeleton, builds and deconstructs. Credit: Eva Nogales lab, University of California, Berkeley.

In this animation, tubulin proteins snap into place like Lego blocks to build a microtubule, part of the cell’s skeleton. When construction ends, this long hollow cylinder falls to pieces from its top end. The breakdown is critical for many basic biological processes, including cell division, when rapidly shortening microtubules pull chromosomes into each daughter cell.

Until recently, scientists didn’t know exactly what drove microtubules to fall apart. A research team led by Eva Nogales of the Lawrence Berkeley National Laboratory and the University of California, Berkeley, now has an explanation.

Using high-powered microscopy, the scientists peered into the structure of a microtubule and found how a chemical reaction puts the stacking tubulin proteins under intense strain. The only thing keeping the proteins from springing apart is the pressure from the addition of more tubulin. So when assembly stops, the microtubule deconstructs.

The team also learned that Taxol, a common cancer drug, relieves this tension and allows microtubules to remain intact indefinitely. With microtubules frozen in place, a cancer cell cannot divide and eventually dies.

Because of this research, scientists now better understand both the success behind a common cancer drug and the molecular basis underlying the workings of microtubules.

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An Insider’s Look at Life: Magnified, an Airport Exhibit of Stunning Microscopy Images

Bubonic plague bacteria on part of the digestive system in a rat flea
What looks like pollen on petals is actually bubonic plague bacteria on the digestive spines of a flea, viewed through a powerful microscope. Credit: B. Joseph Hinnebusch, Elizabeth Fischer and Austin Athman, NIH’s National Institute of Allergy and Infectious Diseases.

Science. Art. Airports. I’ve never used those three words together before. But I’ve been doing it a lot lately while working on Life: Magnified, an exhibit of 46 striking scientific images created by scientists around the country using state-of-the-art microscopes.

The show is at Washington Dulles International Airport, where more than a million travelers will see it over its 6-month run. As our director said in a recent post on another NIGMS blog, “What a great way to share the complexity and beauty of biomedical science with such a large public audience!”

We’ve also set up an online gallery, where the colorful images can be viewed and freely downloaded for research, educational and news media purposes.

The project itself was quite an adventure. When we asked scientists to send us images, our fears of not getting enough attractive, high-resolution options were drowned by a deluge of more than 600 submissions. Then we worried how to sort through them all and make final selections. Doing so required several rounds of online viewing, various ranking systems and a panel of experts. Then the images were printed as large, digital negatives on transparency film.

Artist's rendition of a network diagram. Credit: Allison Kudla, Institute for Systems Biology.
The midnight installation of Life: Magnified involved five people (that’s me in pink), a ladder and lots of rags and glass cleaner. Credit: Woody Machalek.

Dulles is a pretty busy place, so we set up the exhibit when it was quietest—the middle of the night (10 p.m. to 1:30 a.m., to be exact). We swapped out images from the previous photography exhibit and installed the Life: Magnified ones in LED lightboxes mounted in the airport’s Gateway Gallery. It was an eerie and exhilarating feeling to be in a noiseless, nearly empty airport without heavy bags and a long walk to a departure gate.

Less than 12 hours later, I was surprised to receive an e-mail from someone who had passed through the exhibit and sent a few photos. He called the images “stunning.” Similar sentiments were expressed by Science Exit icon, NBC News online Exit icon, The Atlantic Exit icon, The Washington Post Exit icon, National Geographic Exit icon and other publications.

Now I’m being asked about next steps, including whether the exhibit will travel. We’re investigating a variety of options. For now, I hope you’re able to see the exhibit in person. If not, take a look at the images online and see which ones you enjoy most.

Cool Image: Researching Regeneration in a Model Organism

The isolated feeding tube of a flatworm.

The feeding tube, or pharynx, of a planarian worm with cilia shown in red and muscle fibers shown in green. Credit: Carrie Adler/Stowers Institute for Medical Research.

This rainbow-hued image shows the isolated feeding tube, or pharynx, of a tiny freshwater flatworm called a planarian, with the hairlike cilia in red and muscle fibers in green. Scientists use these wondrous worms, which have an almost infinite capacity to regrow all organs, as a simple model system for studying regeneration. A research team led by Alejandro Sánchez Alvarado of the Stowers Institute for Medical Research exploited a method known as selective chemical amputation to remove the pharynx easily and reliably. This allowed the team to conduct a large-scale genetic analysis of how stem cells in a planaria fragment realize what’s missing and then restore it. The researchers initially identified about 350 genes that were activated as a result of amputation. They then suppressed those genes one by one and observed the worms until they pinpointed one gene in particular—a master regulator called FoxA—whose absence completely blocked pharynx regeneration. Scientists believe that researching regeneration in flatworms first is a good way to gain knowledge that could one day be applied to promoting regeneration in mammals.

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Cool Image: Lighting up Brain Cells

Neurons activated with red or blue light.

Neurons activated with red or blue light using algae-derived opsins. Credit: Yasunobu Murata/McGovern Institute for Brain Research at MIT.

The nerve cells, or neurons, lit up in blue and red in this image of mouse brain tissue are expressing algae-derived, light-sensitive proteins called opsins. To control neurons with light, scientists engineer the cells to produce particular opsins, most of which respond to light in the blue-green range. Then they shine light on the cell to activate it. Now, a team of researchers led by Ed Boyden of the Massachusetts Institute of Technology and Gane Ka-Shu Wong of the University of Alberta has discovered an opsin that responds to red light preferentially, enabling them to manipulate two groups of neurons simultaneously with different colors of light and get a more comprehensive look at how those two sets of brain cells interact. Other opsins have shown potential for vision restoration in animal studies, and, because red light causes less damage to tissue than blue-green light, this new opsin might eventually be used for such treatments in humans.

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Cool Image: Denying Microbial Moochers

V. cholerae and V. cholerae

Productive V. cholerae (yellow) and exploitive V. cholerae (red). Credit: Carey Nadell, Princeton University.

What looks like an abstract oil painting is actually an image of several cholera-causing V. cholerae bacterial communities. These communities, called biofilms, include productive and exploitive microbial members. The industrious bacteria (yellow) tend to thrive in denser biofilms (top) while moochers (red) thrive in weaker biofilms (bottom). In an effort to understand this phenomenon, Princeton University researchers led by Bonnie Bassler Exit icon discovered two ways the freeloaders are denied food. They found that some V. cholerae cover themselves with a thick coating to prevent nutritious carbon- and nitrogen-containing molecules from drifting over to the scroungers. In addition, the natural flow of fluids over biofilms can wash away any leftovers. Encouraging such bacterial fairness could boost the efficient breakdown of organic materials into useful products, such as biofuels. On the other hand, counteracting it could lead to better treatment of illnesses, like cholera, by starving the most productive bacteria and thereby weakening the infection.

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Cool Image: Visualizing Viral Activity

Viral RNA (red) in an RSV-infected cell. Credit: Eric Alonas and Philip Santangelo, Georgia Institute of Technology and Emory University.

Viral RNA (red) in an RSV-infected cell. Credit: Eric Alonas and Philip Santangelo, Georgia Institute of Technology and Emory University.

What looks like a colorful pattern produced as light enters a kaleidoscope is an image of a cell infected with respiratory syncytial virus (RSV) illuminated by a new imaging technology. Although relatively harmless in most children, RSV can lead to bronchitis and pneumonia in others. Philip Santangelo Exit icon of the Georgia Institute of Technology and Emory University, along with colleagues nationwide, used multiply-labeled tetravalent RNA imaging probes (MTRIPS) to observe the entry, assembly and replication of RSV inside a living cell. Once introduced into RSV-plagued cells, the MTRIPS latched onto the viral RNA (in the image, red) without altering the level of infectivity. This led to fluorescent RSV viral particles that let the researchers track the viral RNA in host cells and better understand what the virus was doing. The knowledge gained from this new technique might aid in the development of RSV antiviral drugs and possibly a vaccine. Scientists could also one day use the imaging approach to study other RNA viruses, such as the flu and Ebola.

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Cool Images: Holiday Season Cells

Yeast cells deficient in zinc and the Tsa1 protein have protein tangles. Credit: Colin MacDiarmid and David Eide, University of Wisconsin-Madison.

Yeast cells deficient in zinc and the Tsa1 protein have protein tangles. Credit: Colin MacDiarmid and David Eide, University of Wisconsin-Madison.

Just in time for the holidays, we’ve wrapped up a few red and green cellular images from basic research studies. In this snapshot, we see a group of yeast cells that are deficient in zinc, a metal that plays a key role in creating and maintaining protein shape. The cells also lack a protein called Tsa1, which normally keeps proteins from sticking together. Green areas highlight protein tangles caused by the double deficiency. Red outlines the cells. Protein clumping plays a role in many human diseases, including Parkinson’s and Alzheimer’s, so knowledge of why it happens—and what prevents it in healthy cells—could aid the development of treatments.

See more festive images!

Cool Image: Tick Tock, Master Clock

Master clock in mouse brain with the nuclei of the clock cells shown in blue and the VIP molecule shown in green. Credit: Cristina Mazuski in the lab of Erik Herzog, Washington University in St. Louis.

Master clock in mouse brain with the nuclei of the clock cells shown in blue and the VIP molecule shown in green. Credit: Cristina Mazuski in the lab of Erik Herzog, Washington University in St. Louis.

Our biological clocks play a large part in influencing our sleep patterns, hormone levels, body temperature and appetite. A small molecule called VIP, shown in green, enables time-keeping neurons in the brain’s central clock to coordinate daily rhythms. New research shows that, at least in mice, higher doses of the molecule can cause neurons to get out of synch. By desynchronizing mouse neurons with an extra burst of VIP, Erik Herzog Exit icon of Washington University in St. Louis found that the cells could better adapt to abrupt changes in light (day)-dark (night) cycles. The finding could one day lead to a method to reduce jet lag recovery times and help shift workers better adjust to schedule changes.

Learn more:

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Circadian Rhythms Fact Sheet
Tick Tock: New Clues About Biological Clocks and Health Article from Inside Life Science
A Light on Life’s Rhythms Article from Findings Magazine

Healing Wounds, Growing Hair

Wound healing in process. Credit: Yaron Fuchs and Samara Brown in the lab of Hermann Steller, Rockefeller University.

Credit: Yaron Fuchs and Samara Brown in the lab of Hermann Steller, Rockefeller University.

Whether injured by a scrape, minor burn or knife wound, skin goes through the same steps to heal itself. Regrowing hair over new skin is one of the final steps. All the hair you can see on your body is non-living, made up of “dead” cells and protein. It sprouts from living cells in the skin called hair follicle stem cells, shown here in red and orange. For more pictures of hair follicle stem cells—and many other stunning scientific images and videos—go to the NIGMS Image and Video Gallery.

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Cool Video: How Bee Venom Toxin Kills Cells

Credit: Huey Huang, Rice University.

Credit: Huey Huang, Rice University.

A new video, starring the toxin in bee venom, might help scientists design new drugs to combat bacterial infections. The video, by Rice University biophysicist Huey Huang Exit icon, condenses 6.5 minutes into less than a minute to show how the toxin, called melittin, destroys an animal or bacterial cell.

What looks like a red balloon is an artificial cell filled with red dye. Melittin molecules are colored green and float on the cell’s surface like twigs on a pond. As melittin accumulates on the cell’s membrane, the membrane expands to accommodate it. In the video, the membrane stretches into a column on the left.

When melittin levels reach a critical threshold, countless pinhole leaks burst open in the membrane. The cell’s vital fluids—red dye in the video—leak out through these pores. Within minutes, the cell collapses.

Many organisms use such a pore-forming technique to kill attacking bacterial cells. This research reveals molecular-level details of the strategy, bringing pharmaceutical scientists a step closer to harnessing it in the design of new antibiotics.

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