The red spray pictured here may look like fireworks erupting across the night sky on July 4th, but it’s actually a rare glimpse of tiny protein strands called microtubules sprouting and growing from one another in a lab. Microtubules are the largest of the molecules that form a cell’s skeleton. When a cell divides, microtubules help ensure that each daughter cell has a complete set of genetic information from the parent. They also help organize the cell’s interior and even act as miniature highways for certain proteins to travel along.
As their name suggests, microtubules are hollow tubes made of building blocks called tubulins. Scientists know that a protein called XMAP215 adds tubulin proteins to the ends of microtubules to make them grow, but until recently, the way that a new microtubule starts forming remained a mystery.
Sabine Petry and her colleagues at Princeton University developed a new imaging method for watching microtubules as they develop and found an important clue to the mystery. They adapted a technique called total internal reflection fluorescence (TIRF) microscopy, which lit up only a tiny sliver of a sample from frog egg (Xenopus) tissue. This allowed the scientists to focus clearly on a few of the thousands of microtubules in a normal cell. They could then see what happened when they added certain proteins to the sample.
The outermost cells that line blood vessels, lungs, and other organs also act like guards, alert and ready to thwart pathogens, toxins, and other invaders that can do us harm. Called epithelial cells, they don’t just lie passively in place. Instead, they communicate with each other and organize their internal structures in a single direction, like a precisely drilled platoon of soldiers lining up together and facing the same way.
Lining up this way is crucial during early development, when tissues and organs are forming and settling into their final positions in the developing body. In fact, failure to line up in the correct way is linked to numerous birth defects. In the lungs, for instance, epithelial cells’ ability to synchronize with one another is important since these cells have special responsibilities such as carrying mucus up and out of lung tissue. When these cells can’t coordinate their functions, disease results.
Some lung epithelial cells are covered in many tiny, hair-like structures called cilia. All the cilia on lung epithelial cells must move uniformly in a tightly choreographed way to be effective in their mucus-clearing job. This is a unique example of a process called planar cell polarity (PCP) that occurs in cells throughout the body. Researchers are seeking to identify the signals cells use to implement PCP. Continue reading “CLAMP Helps Lung Cells Pull Together”
This sphere could be a prototype design for the 2018 World Cup official match soccer ball, but you won’t see it dribbled around any soccer fields. The image is actually an atomic-scale model of a virus that infects the Salmonella bacterium. Like a soccer ball, both are approximately spherical shapes created by a combination of hexagonal (six-sided) and pentagonal (five-sided) units. Wah Chiu, a biochemist at Baylor College of Medicine, and his colleagues used new computational methods to construct the model from more than 20,000 cryo-electron microscopy (cryo-EM) images. Cryo-EM is a sophisticated technique that uses electron beams for visualizing frozen samples of proteins and other biological specimens.
The researchers’ model, published in a recent issue of PNAS, shows the virus’ protein shell, or capsid, that encloses the virus’ genetic material. Each color shows capsid proteins having the same interactions with their neighbors. The fine resolution allowed researchers to identify the protein interactions essential to building a stable shell. They developed a new approach to checking the accuracy and reliability of the virus model and reporting what parts are the most certain. The approach could be used to evaluate other complex biological structures, potentially leading to better quality models and new avenues for drug design and development.
Our eyes are the gateway to countless brilliant sights. However, as evidenced by the images on this page, the eye itself can be breathtakingly exquisite as well. This May, as we celebrate Healthy Vision Month with the National Eye Institute, we hope sharing the beauty hidden in your eyes will inspire you to take the necessary steps to protect your vision, prevent vision loss and make the most of the vision you have remaining.
Visit NEI to learn more about caring for your eyes.
Happy Healthy Vision Month!
This heart-shaped image shows two mouse skin cancer cells connected to each other with actin, a protein that is part of the cellular skeleton. Researchers use mouse cells like these to tease out the molecular methods that cancer uses to invade new tissues in the body. It turns out that actin plays an essential role.
Cells can move as a collective, or independently. Movement of an individual cell requires a series of carefully controlled steps. Among them, a cell must break contacts with its neighbor cells and change its connections to the proteins and fibers around it. In addition, it must sense and follow a chemical path through the tissue it lies in. To do this, a cell changes shape, molding its membrane into flaps or feet called protrusions reaching in the direction it is traveling. Actin, among a variety of other molecules, is involved in all of these steps, but especially the shape change, when it gathers inside the cell membrane to help form the protrusions. Continue reading “Actin’s Many Roles”
Bacteria use many methods to overcome threats in their environment. One of these ways is forming colonies called biofilms on surfaces of objects. Often appearing like the bubble-shaped fortress represented in this image, biofilms enable bacteria to withstand attacks, compete for space and survive fluctuations in nutrient supply. Bacteria aggregated within biofilms inside our bodies, for example, resist antibiotic therapy more effectively than free swimming cells, making infections difficult to treat. On the other hand, biofilms are also useful for making microbial fuel cells and for waste-water treatment. Learning how biofilms work, therefore, could provide essential tools in our ongoing battle against disease-causing agents and in our efforts to harness beneficial bacterial behaviors. Researchers are now using new imaging techniques to watch how biofilms grow, cell by cell, and to identify more effective ways of disrupting or fostering them.
Until now, poor imaging resolution meant that scientists could not see what individual bacteria in the films are up to as the biofilms grow. The issue is that bacteria are tiny, making imaging each cell, as well as the ability to distinguish each cell in the biofilm community, problematic. Continue reading “Cool Image: Inside a Biofilm Build-up”
As his Christmas gift to himself each year, the late biochemist Roger Tsien treated himself to two weeks of uninterrupted research in his lab. This image is a product of those annual sojourns. While it may look like a pine wreath dotted with crimson berries, it is in fact one of the world’s first color electron micrographs—and the method used to create it may dramatically advance cell imaging.
Electron microscopy (EM) is a time-honored technique for visualizing cell structures that uses beams of accelerated electrons to magnify objects up to 10 million times their actual size. Standard EM images are in grayscale and any color is added in with computer graphics programs after the image is made. With their new technique, Tsien, who received a Nobel Prize for his development of green fluorescent protein into a tool for visualizing details in living cells using light microscopes, and his colleagues have found a way to incorporate color labeling directly into EM. Continue reading “Cool Image: Adding Color to the Gray World of Electron Microscopy”
An exhibit called “Minerals in Medicine” opened at the NIH Clinical Center last month (see slideshow). The display features a fascinating overview of how dozens of minerals are used to create drugs and medical instruments useful in treating disease and maintaining health. The minerals ranged from commonplace ones like quartz, which is used to make medical instruments, to more exotic ones like hubnerite, a source of the metal tungsten, which is used in radiation shielding.
Inspired by this collection, which is co-sponsored by NIH and the Smithsonian Institution, we highlight here examples of “Metals in Medicine.”
Copper and Fat Metabolism
What does a metal like copper have to do with our ability to breakdown fat? Researchers explored this question by observing mice with Wilson’s disease—a rare, inherited condition that causes copper to accumulate in the liver, brain and other vital organs. The mice with the condition usually have larger deposits of fat compared to healthy mice. To confirm that fat metabolism is somehow compromised in these mice, the researchers treated them with a drug that induces the breakdown of fat. And indeed they found that less fat was metabolized in mice with the disease.
In an effort to investigate what role copper may be playing in fat metabolism, the researchers examined adipose tissue, or fat, cells under a microscope to track the metal’s interactions with various proteins in the cell. They discovered that copper inhibits an enzyme called PDE3. This enzyme usually prevents another enzyme called cAMP from helping to break down fat. The researchers concluded that copper actually promotes fat metabolism. This work shows that transition metal nutrients can play signaling roles, which has been previously thought to be restricted to alkali and alkaline earth metals like sodium, potassium and calcium.Continue reading “Metals in Medicine”
Science is beautiful.
For several years, we’ve used this blog to highlight pictures we think are cool, scientifically relevant and visually striking. The images were created by NIGMS-funded researchers in the process of doing their research. Many come from our Life: Magnified collection, which features dozens of stunning photos of life, close-up. We’ll continue to bring you interesting images and information here on Biomedical Beat, but if you can’t get enough of them, we have a new way to share our visual content with you: Instagram.
We’re pleased to announce the launch of our NIGMS Instagram account. We’ll highlight gorgeous images, and bring you the science behind them—straight from our mobile device to yours. Instagram lets us label our images with subject-specific hashtags. You can find our pictures by going on Instagram and searching for #NIGMS. If you’re already an Instagram user, you can follow us @NIGMS_NIH. You can even see our page using a web browser at https://www.instagram.com/nigms_nih/ . Let us know what you think!
Also, if you have any stunning images or videos that relate to scientific areas supported by NIGMS, please send them to us. They might end up on our Instagram feed!