Football image credit: Stock image. The colored contoured lines show the periodic stops in the growth of a bacterial colony. Credit: Süel Lab, UCSD.
What do these images of football fans and bacterial cells have in common? By following simple rules, each individual allows the group to accomplish tasks none of them could do alone—a stadium wave that ripples through the crowd or a cell colony that rebounds after antibiotic treatment.
These collective behaviors are just a few examples of what scientists call emergent phenomena. While the reasons for the emergence of such behavior in groups of birds, fish, ants and other creatures is well understood, they’ve been less clear in bacteria. Two independent research teams have now identified some of the rules bacterial cells follow to enable the colony to persist. Continue reading “The Simple Rules Bacteria Follow to Survive”
Last month, we shared some facts about the microbes that inhabit us. Here’s another: From head to toe, our skin bacteria coexist with chemicals in hygiene products, fibers from clothes and proteins shed by dead or dying skin cells.
Visualizations can give scientists unprecedented views of complex biological processes. Here’s a look at two new ones that shed light on how HIV enters host cells.
Animation of HIV’s Entry Into Host Cells
This video animation of HIV’s entry into a human immune cell is the first one released in Janet Iwasa’s current project to visualize the virus’ life cycle. As they’re completed, the animations will be posted at http://scienceofhiv.org .
We previously introduced you to Janet Iwasa, a molecular animator who’s visualized complex biological processes such as cells ingesting materials and proteins being transported across a cell membrane. She has now released several animations from her current project of visualizing HIV’s life cycle . The one featured here shows the virus’ entry into a human immune cell.
In this composite image of mitochondria in a cell, the left panel shows a conventional optical microscopy image, the middle panel shows a three-dimensional (3-D) STORM image with color indicating depth, and the right panel shows a cross-section of the 3-D STORM image. Credit: Xiaowei Zhuang laboratory, Howard Hughes Medical Institute, Harvard University. View larger image.
Much as a photographer brings distant objects into focus with a telephoto lens, scientists can now see previously indistinct cellular components as small as a few billionths of a meter (nanometers). By overcoming some of the limitations of conventional optical microscopy, a set of techniques known as super-resolution fluorescence microscopy has changed once-blurry images of the nanoworld into well-resolved portraits of cellular architecture, with details never seen before in biology. Reflecting its importance, super-resolution microscopy was recognized with the 2014 Nobel Prize in chemistry.
Using the new techniques, scientists can observe processes in living cells across space and time and study the movements, interactions and roles of individual molecules. For instance, they can identify and track the proteins that allow a virus to invade a cell or those that enable tumor cells to migrate to distant parts of the body in metastatic cancer. The ability to analyze individual molecules, rather than collections of molecules, allows scientists to answer longstanding questions about cellular mechanisms and behavior, such as how cells move along a surface or how certain proteins interact with DNA to regulate gene activity. Continue reading “Field Focus: Bringing Biology Into Sharper View with New Microscopy Techniques”
Modular microfluidics system. Credit: University of Southern California Viterbi School of Engineering.
Like snapping Lego blocks together to build a fanciful space station, scientists have developed a new way to assemble a microfluidics system, a sophisticated laboratory tool for manipulating small volumes of fluids.
Microfluidics systems are used by scientists to perform tasks as diverse as DNA analysis, microbe detection and disease diagnosis. Traditionally, they have been slow and expensive to produce, as each individual “lab on a chip” had to be built from scratch in a special facility.
Now, researchers including Noah Malmstadt of the University of Southern California have harnessed 3-D printing technology to create a faster, cheaper, easier-to-use system . The team first identified the smallest functional pieces of a microfluidics system. Each of these pieces performs one simple task like detecting the size of fluid droplets or mixing two fluids together. After 3-D printing individual components, the team showed that they could be snapped together by hand into a working system in a matter of hours. The individual pieces can be pulled apart and re-assembled as needed before use in an actual experiment, which was impossible with the traditional microfluidics systems.
The researchers have created eight block-like components so far. They hope to start an online community where scientists will share designs for additional components in an open-source database, helping to speed further development of the technology.
This work was funded in part by NIH under grant R01GM093279.
Stem cells grown on a soft surface begin to transform into neurons. Credit: Kiessling Lab, University of Wisconsin-Madison.
If you think this image looks like the fluorescent outline of a brain, you’re on the right track. The green threads show neurons that have just formed from unspecialized cells called stem cells.
Researchers led by Laura Kiessling of the University of Wisconsin-Madison directed the stem cells to become neurons by changing the quality of the surface on which they grew. In experiments testing different gels used to grow stem cells in the lab, the scientists found that the stiffness of those gels influenced cell fate decisions.
When grown on a soft gel with a brain tissue-like surface, the stem cells began to transform into neurons. This happened without the addition of any of the proteins normally used to coax stem cells to specialize into different types of cells.
A better understanding of how stem cell fate is influenced by the mechanical properties of a surface could help researchers who are trying to harness the blank slate cells for tissue regeneration or other therapeutic uses.
This work also was funded by NIH’s National Institute of Biomedical Imaging and Bioengineering; National Heart, Lung, and Blood Institute; and National Institute of Neurological Disorders and Stroke.
Meet mitochondria: cellular compartments, or organelles, that are best known as the powerhouses that convert energy from the food we eat into energy that runs a range of biological processes.
As you can see in this close-up of mitochondria from a rat’s heart muscle cell, the organelles have an inner membrane that folds in many places (and that appears here as striations). This folding vastly increases the surface area for energy production. Nearly all our cells have mitochondria, but cells with higher energy demands have more. For instance, a skin cell has just a few hundred, while the cell pictured here has about 5,000.
Scientists are discovering there’s more to mitochondria than meets the eye, especially when it comes to understanding and treating disease.
Read more about mitochondria in this Inside Life Science article.
A healthy cell (green) that has ingested dying cells (purple). Credit: Toru Komatsu, University of Tokyo.
In this image, a healthy cell (green) has engulfed a number of dying cells (purple) just as a predator might ingest wounded or dying prey. A team of researchers is hoping to use this same strategy at the cellular level to help treat infection, neurodegenerative diseases or cancer.
Our bodies routinely use a process called phagocytosis to rid themselves of unhealthy cells. Takanari Inoue at Johns Hopkins University and collaborators at the University of Tokyo set out to investigate the molecular underpinnings of phagocytosis. Their goal was to endow laboratory-grown human cells with phagocytotic skills, namely the ability to recognize, swallow and digest dying cells. The scientists tried to do this by inserting into the cells two molecules known to play a role in phagocytosis.
The engineered cells accomplished the first two tasks—they recognized and surrounded dying cells. But they didn’t digest what they’d engulfed. Now the researchers are looking for a molecular trigger to get the engineered cells to complete this last task.
Eventually, the scientific team aims to build artificial cells that are programmed to target and destroy abnormal cells, such as those ravaged by bacteria, cancer or other diseases.
Learn more: Johns Hopkins News Release
How Cells Take Out the Trash Article from Inside Life Science
Cellular Suicide: An Essential Part of Life Article from Inside Life Science
In this image, the optic nerve (left) leaves the back of the retina (right). Where the retina meets the optic nerve, visual information begins its journey from the eye to the brain. Taking a closer look, axons (purple), which carry electrical and chemical messages, meet astrocytes (yellow), a type of brain cell. Recent research has found a new and surprising role for these astrocytes.
Biologists have long thought that all cells, including neurons, degrade and reuse pieces of their own mitochondria, the little powerhouses that provide energy to cells. Using cutting-edge imaging technology, researchers led by Mark Ellisman of the University of California, San Diego, and Nicholas Marsh-Armstrong of Johns Hopkins University have caught neurons in the mouse optic nerve in the act of passing some of their worn out mitochondria to neighboring astrocytes, which then did the dirty work of recycling.
The researchers also showed that neurons in other regions of the brain appear to outsource mitochondrial breakdown to astrocytes as well. They suggest that it will be important to confirm that this process occurs in other parts of the brain and to determine how possible defects in the outsourcing may contribute to or underlie neuronal dysfunction or neurodegenerative diseases.
This work also was funded by NIH’s National Eye Institute and National Institute on Drug Abuse.
University of California, San Diego News Release and Blog Posting
How Cells Take Out the Trash Article from Inside Life Science
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.
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.
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.