Snapshots of Life: A Flare for the Dramatic

lipid-covered water drop

Credit: Valentin Romanov, University of Utah, Salt Lake City

Oil and water may not mix, but under the right conditions—like those in the photo above—it can sure produce some interesting science that resembles art. You’re looking at a water droplet suspended in an emulsion of olive oil (black and purple) and lipids, molecules that serve as the building blocks of cell membranes. Each lipid has been tagged with a red fluorescent marker, and what look like red and yellow flames are the markers reacting to a beam of UV light. Their glow shows the lipids sticking to the surface of the water droplet, which will soon engulf the droplet to form a single lipid bilayer, which can later be transformed into a lipid bilayer that closely resembles a cell membrane. Scientists use these bubbles, called liposomes, as artificial cells for a variety of research purposes.

In this case, the purpose is structural biology studies. Valentin Romanov, the graduate student at the University of Utah, Salt Lake City, who snapped the image, creates liposomes to study proteins that help cells multiply. By encapsulating and letting the proteins interact with lipids in the artificial cell membrane, Romanov and his colleagues in the NIH-supported labs of Bruce Gale at the University of Utah and Adam Frost at the University of California, San Francisco, can freeze and capture their changing 3D structures at various points in the cell division process with high-resolution imaging techniques. These snapshots will help the researchers to understand in finer detail how the proteins work and perhaps to design drugs to manipulate their functions.

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Out of Africa: DNA Analysis Points to a Single Major Exodus

View of Africa from space

Credit: NASA

If you go back far enough, the ancestors of all people trace to Africa. That much is clear. We are all Africans. But there’s been considerable room for debate about exactly when and how many times modern humans made their way out of Africa to take up residence in distant locations throughout the world. It’s also unclear what evolutionary or other factors might have driven our human ancestors to set off on such a perilous and uncertain journey (or journeys) in the first place.

By analyzing 787 newly sequenced complete human genomes representing more than 280 diverse and understudied populations, three new studies—two of which received NIH funding—now help to fill in some of those missing pages of our evolutionary history. The genomic evidence suggests that the earliest human inhabitants of Eurasia came from Africa and began to diverge genetically at least 50,000 years ago. While the new studies differ somewhat in their conclusions, the findings also lend support to the notion that our modern human ancestors dispersed out of Africa primarily in a single migratory event. If an earlier and ultimately failed voyage occurred, it left little trace in the genomes of people alive today.

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Creative Minds: Making a Miniature Colon in the Lab

Gut on a Chip

Caption: Top down view of gut tissue monolayer grown on an engineered scaffold, which guides the cells into organized crypts structures similar to the conformation of crypts in the human colon. Areas between the circles represent the flat lumenal surface.
Credit: Nancy Allbritton, University of North Carolina, Chapel Hill

When Nancy Allbritton was a child in Marksville, LA, she designed and built her own rabbit hutches. She also once took apart an old TV set to investigate the cathode ray tube inside before turning the wooden frame that housed the TV into a bookcase, which, by the way, she still has. Allbritton’s natural curiosity for how things work later inspired her to earn advanced degrees in medicine, medical engineering, and medical physics, while also honing her skills in cell biology and analytical chemistry.

Now, Allbritton applies her wide-ranging research background to design cutting-edge technologies in her lab at the University of North Carolina, Chapel Hill. In one of her boldest challenges yet, supported by a 2015 NIH Director’s Transformative Research Award, Allbritton and a multidisciplinary team of collaborators have set out to engineer a functional model of a large intestine, or colon, on a microfabricated chip about the size of a dime.

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Of Mice and Men: Study Pinpoints Genes Essential for Life

Many people probably think of mice as unwanted household pests. But over more than a century, mice have proven to be incredibly valuable in medical research. One of many examples is how studies in mice are now helping researchers understand how mammalian genomes work, including the human genome. Scientists have spent decades inactivating, or “knocking out,” individual genes in laboratory mice to learn which tissues or organs are affected when a specific gene is out of order, providing valuable clues about its function.

More than a decade ago, NIH initiated a project called KOMP—the Knockout Mouse Project [1]. The goal was to use homologous recombination (exchange of similar or identical DNA) in embryonic stem cells from a standard mouse strain to knock out all of the mouse protein-coding genes. That work has led to wide availability of such cell lines to investigators with interest in specific genes, saving time and money. But it’s one thing to have a cell line with the gene knocked out, it’s even more interesting (and challenging) to determine the phenotype, or observable characteristics, of each knockout. To speed up that process in a scientifically rigorous and systematic manner, NIH and other research funding agencies teamed to launch an international research consortium to turn those embryonic stem cells into mice, and ultimately to catalogue the functions of the roughly 20,000 genes that mice and humans share. The consortium has just released an analysis of the phenotypes of the first 1,751 new lines of unique “knockout mice” with much more to come in the months ahead. This initial work confirms that about a third of all protein-coding genes are essential for live birth, helping to fill in a major gap in our understanding of the genome.

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Feed a Virus, Starve a Bacterium?

Woman eating hot soup in bed


Yes, the season of colds and flu is coming. You’ve probably heard the old saying “feed a cold and starve a fever.” But is that sound advice? According to new evidence from mouse studies, there really may be a scientific basis for “feeding” diseases like colds and flu that are caused by viruses, as well as for “starving” certain fever-inducing conditions caused by bacteria.

In the latest work, an NIH-funded research team found that providing nutrition to mice infected with the influenza virus significantly improved their survival. In contrast, the exact opposite proved true in mice infected with Listeria, a fever-inducing bacterium. When researchers forced Listeria-infected mice to consume even a small amount of food, they all died.

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