Powerful Antibiotics Found in Dirt

Dirt

Caption: Researchers found a new class of antibiotics in a collection of about 2,000 soil samples.
Credit: Sean Brady, The Rockefeller University, New York

Many of us think of soil as lifeless dirt. But, in fact, soil is teeming with a rich array of life: microbial life. And some of those tiny, dirt-dwelling microorganisms—bacteria that produce antibiotic compounds that are highly toxic to other bacteria—may provide us with valuable leads for developing the new drugs we so urgently need to fight antibiotic-resistant infections.

Recently, NIH-funded researchers discovered a new class of antibiotics, called malacidins, by analyzing the DNA of the bacteria living in more than 2,000 soil samples, including many sent by citizen scientists living all across the United States [1]. While more work is needed before malacidins can be tried in humans, the compounds successfully killed several types of multidrug-resistant bacteria in laboratory tests. Most impressive was the ability of malacadins to wipe out methicillin-resistant Staphylococcus aureus (MRSA) skin infections in rats. Often referred to as a “super bug,” MRSA threatens the lives of tens of thousands of Americans each year [2].

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Snapshots of Life: The Brain’s Microscopic Green Trash Bins

Zebrafish brain

Credit: Marina Venero Galanternik, Daniel Castranova, Tuyet Nguyen, and Brant M. Weinstein, NICHD, NIH

There are trash bins in our homes, on our streets, and even as a popular icon on our desktop computers. And as this colorful image shows, trash bins of the cellular variety are also important in the brain.

This image—a winner in the Federation of American Societies for Experimental Biology’s 2017 BioArt competition—shows the brain of an adult zebrafish, a popular organism for studying how the brain works. It captures dense networks of blood vessels (red) lining the outer surface of the brain. Next to many of these vessels sit previously little-studied cells called fluorescent granular perithelial cells (yellowish green). Researchers now believe these cells, often shortened to FGPs, act much like trash receptacles that continuously take in and store waste products to keep the brain tidy and functioning well.

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KRAS Targeted Cancer Strategy Shows Early Promise

KRAS in active and inactive states

Caption: Mutant KRAS protein (white) keeps switch (red/pink) open in active state for GTP (arrow). After treatment with ARS-1620 (blue), switch is trapped in inactive GDP-bound state.
Credit: Adapted from Cell. 2018 Jan 25;172(3):578-589.

Of the more than 1.7 million Americans expected to be diagnosed with cancer this year, nearly one-third will have tumors that contain at least one mutation in the RAS family of genes [1]. That includes 95 percent of pancreatic cancers and 45 percent of colon cancers. These mutations result in the production of defective proteins that can drive cancer’s uncontrolled growth, as well as make cancers resistant to therapies. As you might expect, RAS has emerged as a major potential target for fighting cancer. Unfortunately, it is a target that’s proven very difficult to “hit” despite nearly three decades of work by researchers in both the private and public sectors, leading NIH’s National Cancer Institute to begin The RAS Initiative in 2013. This important effort has made advances with RAS that have translational potential.

Recently, I was excited to hear of progress in targeting a specific mutant form of KRAS, which is a protein encoded by a RAS gene involved in many lung cancers and some pancreatic and colorectal cancers. The new study, carried out by a pharmaceutical research team in mouse models of human cancer, is the first to show that it is possible to shrink a tumor in a living creature by directly inhibiting mutant KRAS protein [2].

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Creative Minds: Building Better Computational Models of Common Disease

Hilary Finucane

Hilary Finucane

Not so long ago, Hilary Finucane was a talented young mathematician about to complete a master’s degree in theoretical computer science. As much as she enjoyed exploring pure mathematics, Finucane had begun having second thoughts about her career choice. She wanted to use her gift for numbers in a way that would have more real-world impact.

The solution to her dilemma was, literally, standing right by her side. Her husband Yakir Reshef, also a mathematician, was developing a new algorithm at the Broad Institute of MIT and Harvard, Cambridge, MA, to improve detection of unexpected associations in large data sets. So, Finucane helped the Broad team with modeling biomedical topics ranging from the gut microbiome to global health. That work led to her co-authoring a paper in the journal Science [1], providing a strong start to what’s shaping up to be a rewarding career in computational biology.

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Sequencing Human Genome with Pocket-Sized “Nanopore” Device

MinION sequencing device

Caption: MinION sequencing device plugged into a laptop/Oxford Nanopore Technologies

It’s hard to believe, but it’s been almost 15 years since we successfully completed the Human Genome Project, ahead of schedule and under budget. I was proud to stand with my international colleagues in a celebration at the Library of Congress on April 14, 2003 (which happens to be my birthday), to announce that we had stitched together the very first reference sequence of the human genome at a total cost of about $400 million. As remarkable as that achievement was, it was just the beginning of our ongoing effort to understand the human genome, and to use that understanding to improve human health.

That first reference human genome was sequenced using automated machines that were the size of small phone booths.  Since then, breathtaking progress has been made in developing innovative technologies that have made DNA sequencing far easier, faster, and more affordable. Now, a report in Nature Biotechnology highlights the latest advance: the sequencing and assembly of a human genome using a pocket-sized device [1]. It was generated using several “nanopore” devices that can be purchased online with a “starter kit” for just $1,000. In fact, this new genome sequence—completed in a matter of weeks—includes some notoriously hard-to-sequence stretches of DNA, filling several key gaps in our original reference genome.

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