Chris Palmer

About Chris Palmer

Chris, a former neuroscientist, enjoys communicating about new research discoveries and trends in science through articles, videos, and infographics.

Interview With a Scientist: Thomas O’Halloran, Metal Maestro

Inside our bodies is a surprising amount of metal. Not enough to set off the scanners at the airport or make us rich, but enough to fill each of our cells with billions of metal ions, including calcium, iron, copper and zinc. These ions facilitate critical biological functions.

However, too much of any metal can be toxic, while too little can cause disease. Our cells carefully monitor and control their metal content using a whole series of proteins that bind, sense and transport metal ions.

Keeping tabs on why and how metals flow into and out of our cells is a passion of Thomas O’Halloran Exit icon, professor of chemistry and molecular biosciences at Northwestern University in Illinois. For the past three decades, O’Halloran has investigated how fluctuations in the amount of metal ions inside cells influence gene expression, cell growth and other vital functions. Using a variety of approaches, he has uncovered new types of proteins that bind metal ions and investigated the role that imbalances in these ions play in a number of disease-related physiological processes.

One recent focus of his studies has been how zinc regulates oocyte (egg cell) maturation and fertilization. Ultimately, his work could help us better understand infertility, cancer and certain bacterial infections.

There’s an “Ome” for That

In the 13 years since the sequencing of the human genome, the list of “omes” has proliferated. Drop us a comment with your favorite ome—we may feature it in a follow-up post next month.Have you ever collected coins, cards, toy trains, stuffed animals? Did you feel the need to complete the set? If so, then you may be a completist. A completist will go to great lengths to acquire a complete set of something.

Scientists can also be completists who are inspired to identify and catalog every object in a particular field to further our understanding of it. For example, a comprehensive parts list of the human body—and of other organisms that are important in biomedical research—could aid in the development of novel treatments for diseases in the same way that a parts list for a car enables auto mechanics to build or repair a vehicle.

More than 15 years ago, scientists figured out how to catalog every gene in the human body. In the years since, rapid advances in technology and computational tools have allowed researchers to begin to categorize numerous aspects of the biological world. There’s actually a special way to name these collections: Add “ome” to the end of the class of objects being compiled. So, the complete set of genes in the body is called the “genome,” and the complete set of proteins is called the “proteome.”

Below are three -omes that NIH-funded scientists work with to understand human health.

Genome

Illustration of the entire outer shell of the bacteriophage MS2. Credit: Wikimedia Commons, Naranson.

The genome is the original -ome. In 1976, Belgium scientists identified all 3,569 DNA bases—the As, Cs, Gs and Ts that make up DNA’s code—in the genes of bacteriophage MS2, immortalizing this bacteria-infecting virus as possessing the first fully sequenced genome.

Over the next two decades, a small handful of additional genomes from other microorganisms followed. The first animal genome was completed in 1998. Just 5 years later, scientists identified all 3.2 billion DNA bases in the human genome, representing the work of more than 1,000 researchers from six countries over a period of 13 years. Continue reading

Our Complicated Relationship With Viruses

Illustration of Influenza Virus H1N1. Swine Flu.
Nearly 10 percent of the human genome is derived from the genes of viruses. Credit: Stock image.

When viruses infect us, they can embed small chunks of their genetic material in our DNA. Although infrequent, the incorporation of this material into the human genome has been occurring for millions of years. As a result of this ongoing process, viral genetic material comprises nearly 10 percent of the modern human genome. Over time, the vast majority of viral invaders populating our genome have mutated to the point that they no longer lead to active infections. But they are not entirely dormant.

Sometimes, these stowaway sequences of viral genes, called “endogenous retroviruses” (ERVs), can contribute to the onset of diseases such as cancer. They can also make their hosts susceptible to infections from other viruses. However, scientists have identified numerous cases of viral hitchhikers bestowing crucial benefits to their human hosts—from protection against disease to shaping important aspects of human evolution, such as the ability to digest starch.

Protecting Against Disease

Geneticists Cedric Feschotte Exit icon, Edward Chuong Exit icon and Nels Elde Exit icon at the University of Utah have discovered that ERVs lodged in the human genome can jump start the immune system.

For a virus to successfully make copies of itself inside a host cell, it needs molecular tools similar to the ones its host normally uses to translate genes into proteins. As a result, viruses have tools meticulously shaped by evolution to commandeer the protein-producing machinery of human cells. Continue reading

Metals in Medicine

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 huebnerite, 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

Fluorescent imaging of copper in white fat cells from mice.

Fluorescent imaging of copper in white fat cells from mice. The left panel shows fat cells with normal levels of copper, and the right panel shows fat cells deficient in copper. Credit: Lakshmi Krishnamoorthy and Joseph Cotruvo Jr., University of California, Berkeley.

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

Exploring the Evolution of Spider Venom to Improve Human Health

Brown recluse

Female brown recluse spider. Credit Matt Bertone, North Carolina State University.

This Halloween, you’re not likely to see many trick-or-treaters dressed as spiders. Google Trends pegs “Spider” as the 87th most searched-for Halloween costume, right between “Hippie” and “The Renaissance.” But don’t let your guard down. Spiders are everywhere.

“I grew up on a farm in Indiana and had the luxury of exploring and turning over rocks and being curious. Any feelings of being grossed out by spiders were rapidly replaced by my feelings of awe for how amazing and diverse these creatures are.”-- Greta Binford

More than 46,000 species of spiders creepy crawl across the globe, on every continent except Antarctica. Each species produces a venom composed of an average of 500 distinct toxins, putting the conservative estimate of unique venom compounds at more than 22 million. This staggering diversity of venoms, collectively referred to as the venome, has only begun to be explored. Continue reading

Interview With a Scientist: Laura Kiessling, Carbohydrate Scientist

The outside of every cell on Earth—from the cells in your body to single-celled microorganisms—is blanketed with a coat of carbohydrates, or sugar molecules, that extend from the cell surface, branching off and bending as they interface with the extra-cellular space. The specific patterns in which these carbohydrates are arranged serve as an ID code that help cells recognize each other. For example, human liver cells have one pattern, while human red blood cells another. Certain diseases can even alter the pattern of surface carbohydrates, which is one way the body can recognize damaged cells. On foreign cells, including invading bacteria such as Streptococcus pneumoniae, the carbohydrate coat is even more distinct.

Laura Kiessling Exit icon, a professor of chemistry at the University of Wisconsin, Madison, studies how carbohydrate coats are assembled and how cells use these coats to tell friend from foe. The implications of her research suggest strategies for targeting tumors, fighting diseases of inflammation and, as she discusses in this video, developing new classes of antibiotics.

The Science of Size: Rebecca Heald Explores Size Control in Amphibians

Rebecca Heald
Credit: Mark Hanson.
Rebecca Heald
Grew up in: Greenville, Pennsylvania
Studied at: Hamilton College, Rice University, Harvard Medical School
Job site: University of California, Berkeley
Favorite hobby: Cycling

A 50-pound frog isn’t some freak of nature or a creepy Halloween prank. It’s a thought experiment conceived by Rebecca Heald, a cell biologist at the University of California, Berkeley Exit icon, who is studying the factors that control size in animals.

Heald’s “50-pound frog project” speaks to the power of evolution and to scientists’ ability to modify the physical characteristics of an organism by altering its genome. The project also incorporates many of Heald’s fascinating discoveries studying amphibian eggs and embryos.

In amphibians, unlike in mammals, there are striking correlations among the size of the animals’ genomes (an organism’s complete set of genes) and several aspects of the animals’ size. For example, amphibians with large genomes tend to be bigger than those with smaller genomes. Larger genomes also correspond to larger cells and larger organelles (specialized cellular structures such as the nucleus). Heald has also demonstrated that these seemingly fixed parameters can be tweaked in the lab. Continue reading

Interview With a Scientist: Janet Iwasa, Molecular Animator

The world beneath our skin is full of movement. Hemoglobin in our blood grabs oxygen and delivers it throughout the body. Molecular motors in cells chug along tiny tubes, hauling cargo with them. Biological invaders like viruses enter our bodies, hijack our cells and reproduce wildly before bursting out to infect other cells.

To make sense of the subcutaneous world, Janet Iwasa, a molecular animator at the University of Utah, creates “visual hypotheses”—detailed animations that convey the latest thinking of how biological molecules interact.

“It’s really building the animated model that brings insights,” Iwasa told Biomedical Beat in 2014. “When you’re creating an animation, you’re really grappling with a lot of issues that don’t necessarily come up by any other means. In some cases, it might raise more questions, and make people go back and do some more experiments when they realize there might be something missing.”

Iwasa has collaborated with numerous scientists to develop animations of a range of biological processes and structures Exit icon. Recently, she’s undertaken an ambitious, multi-year project to animate HIV reproduction Exit icon.

Interview With a Slime Mold: Racing for New Knowledge

Dictyostelium discoideum
Credit: Wikimedia Commons, Usman Bashir.
Dictyostelium discoideum
Natural habitat: Deciduous forest soil and moist leaf litter
Favorite food: Bacteria
Top speed: 8 micrometers per minute

Like the athletes in Rio, the world’s most highly advanced microbial runners recently gathered in Charlestown, Massachusetts, to find out which ones could use chemical cues to most quickly navigate a maze-like microfluidic racecourse. The winners’ prize: credit for helping scientists learn more about how immune system cells navigate through the human body on their way to fight disease.

Credit: Daniel Irimia of Massachusetts General Hospital, and Monica Skoge and Albert Bae of the University of California, San Diego.

The finalists were a group of soil-dwelling slime molds called Dictyostelium that were genetically engineered by a pair of Dutch biochemists to detect minuscule chemical changes in the environment. The racers used their enhanced sense of “smell” to avoid getting lost on their way to the finish line.

While researchers have been racing the genetically souped-up microbes at annual events for a few years—another competition Exit icon is scheduled for October 26—scientists have been studying conventional Dictyostelium for decades to investigate other important basic life processes including early development, gene function, self/non-self recognition, cell-type regulation, chemical signaling and programmed cell death. Continue reading

A World Without Pain

In an immersive virtual reality environment called “Snow World,” burn patients distract themselves from their pain by tossing snow balls, building snowmen and interacting with penguins. Credit: Ari Hollander and Howard Rose, copyright Hunter Hoffman, UW, www.vrpain.com Exit icon.

You glide across an icy canyon where you meet smiling snowmen, waddling penguins and a glistening river that winds forever. You toss snowballs, hear them smash against igloos, then watch them explode in vibrant colors.

Back in the real world, a dentist digs around your mouth to remove an impacted tooth, a procedure that really, really hurts. Could experiencing a “virtual” world distract you from the pain? NIGMS grantees David Patterson Exit icon and Hunter Hoffman Exit icon show it can.

Patterson, a psychologist at the University of Washington (UW) in Seattle, and Hoffman, a UW cognitive psychologist, helped create the virtual reality program “Snow World” in an effort to reduce excessive pain experienced by burn patients. However, the researchers expect Snow World to help alleviate all kinds of pain, including pain experienced during dental procedures. Continue reading